Optical element based on a polymer structure incorporating an inorganic material
阅读说明:本技术 基于结合有无机材料的聚合物结构的光学元件 (Optical element based on a polymer structure incorporating an inorganic material ) 是由 M·M·韦斯特 C·佩罗兹 M·梅利 于 2018-12-28 设计创作,主要内容包括:本公开涉及显示系统,更具体地,涉及增强现实显示系统。在一个方面,一种制造光学元件的方法包括提供具有第一折射率并且在可见光谱中透明的衬底。该方法还包括在衬底上形成周期性重复的聚合物结构。该方法还包括将衬底暴露于金属前体,然后暴露于氧化前体。在压力和温度下执行暴露衬底,以使得包括金属前体的金属的无机材料被结合到周期性重复的聚合物结构中,从而形成被配置为衍射可见光的周期性重复的光学结构的图案。该光学结构具有大于第一折射率的第二折射率。(The present disclosure relates to display systems, and more particularly, to augmented reality display systems. In one aspect, a method of manufacturing an optical element includes providing a substrate having a first index of refraction and being transparent in the visible spectrum. The method also includes forming a periodically repeating polymer structure on the substrate. The method also includes exposing the substrate to a metal precursor followed by an oxidizing precursor. Exposing the substrate is performed under pressure and temperature such that an inorganic material comprising a metal of the metal precursor is incorporated into the periodically repeating polymer structure, thereby forming a pattern of periodically repeating optical structures configured to diffract visible light. The optical structure has a second refractive index that is greater than the first refractive index.)
1. A method of manufacturing an optical element, comprising:
providing a substrate having a first index of refraction and being transparent in the visible spectrum;
forming a periodically repeating polymer structure on the substrate; and
exposing the substrate to a metal precursor, and then to an oxidizing precursor,
wherein the exposing is performed under pressure and temperature such that an inorganic material comprising a metal of the metal precursor is incorporated into the periodically repeating polymer structure, thereby forming a pattern of periodically repeating optical structures configured to diffract visible light, the optical structures having a second refractive index that is greater than the first refractive index.
2. An optical element, comprising:
a substrate having a first index of refraction and being transparent in the visible spectrum; and
a pattern of periodically repeating optical structures formed on the substrate and configured to diffract visible light, the optical structures having a second refractive index greater than the first refractive index and comprising a polymer material having an inorganic material incorporated therein.
3. The optical element of claim 2, wherein the polymer material has a bulk refractive index that is less than the second refractive index, and the inorganic material has a bulk refractive index that is higher than the second refractive index.
4. The optical element of claim 2, wherein the second refractive index is greater than 1.7 and at least 0.2 greater than the first refractive index.
5. The optical element of claim 2, wherein the substrate has a refractive index greater than 1.5.
6. The optical element of claim 2, wherein the polymeric material comprises a photoresist.
7. The optical element of claim 2, wherein the inorganic material comprises a transition metal oxide.
8. The optical element of claim 7, wherein the inorganic material comprises a metal oxide.
9. The optical element of claim 7, wherein the metal oxide comprises an oxide selected from the group comprising: aluminum oxide, zinc oxide, zirconium oxide, hafnium oxide, and titanium oxide.
10. The optical element of claim 7, wherein the inorganic material is incorporated into a surface region of the optical structure and a core region of the optical structure has no inorganic material incorporated therein.
11. The optical element of claim 2, wherein adjacent ones of the periodically repeating optical structures are separated by a space, wherein a surface of the substrate in the space is free of the inorganic material disposed thereon.
12. An optical element according to claim 2, wherein adjacent ones of the periodically repeating optical structures are spaced apart, wherein a surface of the substrate in the spaces has formed thereon a layer of polymeric material having the inorganic material incorporated therein, the layer having a thickness less than a height of the optical structures.
13. The optical element of claim 12, wherein the entire thickness of the layer of polymeric material formed in the space is bonded to the inorganic material.
14. The optical element of claim 12, wherein the layer of polymeric material formed in the space has a partial thickness bonded to the inorganic material in the surface region and a partial thickness not bonded to the inorganic material.
15. The optical element of claim 2, wherein the substrate is configured such that visible light diffracted by the periodically repeating optical structure propagates under total internal reflection.
16. The optical element of claim 2, wherein the periodically repeating optical structures comprise a super-surface.
17. The optical element of claim 2, wherein the substrate is configured such that visible light is guided therein under total internal reflection and diffracted out of the substrate by the periodically repeating optical structure.
18. The optical element of claim 2, wherein the substrate is configured such that visible light is guided therein under total internal reflection and diffracted by the periodically repeating optical structure so as to alter a direction in which the light beam propagates within the substrate by total internal reflection.
19. An optical system, comprising:
an optical element comprising:
a substrate having a first refractive index and being transparent in the visible spectrum, an
A pattern of periodically repeating optical structures formed on the substrate and configured to diffract visible light, the optical structures having a second refractive index greater than the first refractive index and comprising a polymer material having an inorganic material incorporated therein,
wherein the periodically repeating optical structure comprises a nanobeam arranged as a super-surface comprising a plurality of repeating unit cells, each unit cell comprising:
a first set of nanobeams formed by one or more first nanobeams; and
a second set of nanobeams formed by one or more second nanobeams disposed adjacent to the one or more first nanobeams and spaced apart from each other at sub-wavelength intervals,
wherein the one or more first nanobeams and the plurality of second nanobeams are elongated in different orientation directions.
20. The optical system of claim 19, wherein the unit cell repeats with a period less than or equal to about 10nm to 1 μ ι η.
21. The optical system of claim 19, wherein the one or more first and second nanobeams are oriented at an angle relative to each other to induce a phase difference between the visible light diffracted by the one or more first nanobeams and the visible light diffracted by the second nanobeams.
22. The optical system of claim 19, wherein the one or more first and second nanobeams are oriented in an orientation direction that is rotated about 90 degrees relative to each other.
23. The optical system of claim 19, wherein the unit cell repeats with a period less than or equal to the wavelength, wherein the wavelength is within the visible spectrum.
24. The optical system of claim 19, wherein the one or more first and second nanobeams have a height less than the wavelength.
25. An optical system comprising a waveguide configured to propagate visible light, the optical system comprising:
a substrate having a first index of refraction and being transparent in the visible spectrum to enable light to be guided therein by total internal reflection; and
a pattern of periodically repeating optical structures formed on the substrate and configured to diffract visible light, the optical structures having a second refractive index greater than the first refractive index and comprising a polymer material having an inorganic material incorporated therein,
wherein the periodically repeating optical structure is arranged to diffract light at a diffraction angle relative to the direction of incident light and to cause the diffracted light to propagate under total internal reflection in the substrate, or to diffract light guided under total internal reflection within the substrate at a diffraction angle relative to the direction of light guided within the substrate.
26. The optical system of claim 25, wherein the polymer material has a bulk refractive index that is less than the second refractive index, and the inorganic material has a bulk refractive index that is higher than the second refractive index.
27. The optical system of claim 25, wherein the second refractive index is greater than 1.7 and at least 0.2 greater than the first refractive index.
28. The optical system of claim 25, wherein the diffraction angle exceeds 50 degrees.
29. The optical system of claim 25, further comprising a light source configured to emit light of the wavelength to the pattern of periodically repeating optical structures.
30. The optical system of claim 25, further comprising a spatial light modulator configured to modulate light from the light source and output the modulated light to the pattern of periodically repeating optical structures.
31. The optical system of claim 25, wherein the periodically repeating optical structures are arranged to diffract light at diffraction angles relative to the direction of incident light and to propagate the diffracted light under total internal reflection in the substrate.
32. The optical system of claim 25, wherein the periodically repeating optical structures are arranged to diffract light guided under total internal reflection within the substrate at diffraction angles relative to a direction of the light guided within the substrate.
33. The optical system of claim 32, wherein the periodically repeating optical structures are arranged to diffract light guided under total internal reflection within the substrate out of the substrate.
34. A head-mounted display device configured to project light to an eye of a user to display augmented reality image content, the head-mounted display device comprising:
a frame configured to be supported on a head of a user;
a display disposed on the frame, at least a portion of the display comprising:
one or more waveguides that are transparent and are disposed at a location in front of the user's eyes when the user wears the head mounted display device such that the transparent portion transmits light from a portion of the environment in front of the user to the user's eyes to provide a view of the portion of the environment in front of the user;
one or more light sources; and
at least one diffraction grating configured to couple light from the light source into or out of the one or more waveguides, the diffraction grating comprising:
a substrate having a first index of refraction and being transparent in the visible spectrum; and
a pattern of periodically repeating optical structures formed on a substrate and configured to diffract visible light, the optical structures having a second refractive index greater than the first refractive index and comprising a polymer material having an inorganic material incorporated therein.
35. The apparatus of claim 34, wherein the one or more light sources comprise a fiber optic scanning projector.
36. The apparatus of claim 34, the display configured to project light into a user's eye to present image content to the user on a plurality of depth planes.
37. A method of manufacturing an optical element, comprising:
providing a substrate transparent in the visible spectrum;
forming a periodically repeating polymer structure having a first refractive index on the substrate; and
exposing the substrate to a metal precursor, and then to an oxidizing precursor,
wherein the exposing is performed under pressure and temperature such that an inorganic material comprising a metal of the metal precursor is incorporated into the periodically repeating polymer structure, thereby increasing the refractive index of the periodically repeating polymer structure to form a pattern of periodically repeating optical structures configured to diffract visible light.
Technical Field
The present disclosure relates to display systems, and more particularly, to augmented reality systems.
Background
Modern computing and display technologies have facilitated the development of systems for so-called "virtual reality" or "augmented reality" experiences, in which digitally reproduced images, or portions thereof, are presented to a user in such a way that they appear real or can be perceived as real. Virtual reality or "VR" scenes typically involve the presentation of digital or virtual image information without transparency to other real-world visual inputs; augmented reality or "AR" scenes typically involve the presentation of digital or virtual image information as an augmentation to the visualization of the real world around the user. A mixed reality or "MR" scene is an AR scene and typically involves virtual objects that integrate into and respond to the natural world. For example, an MR scene may include AR image content that appears to be blocked by or otherwise perceived as interacting with objects in the real world.
Referring to fig. 1, an augmented
The systems and methods disclosed herein address various challenges associated with AR and VR technology.
Disclosure of Invention
In a first aspect, a method of manufacturing an optical element includes providing a substrate having a first index of refraction and being transparent in the visible spectrum. The method also includes forming a periodically repeating polymer structure on the substrate. The method also includes exposing the substrate to a metal precursor followed by an oxidizing precursor. Exposing the substrate is performed under pressure and temperature such that an inorganic material comprising a metal of the metal precursor is incorporated into the periodically repeating polymer structure, thereby forming a pattern of periodically repeating optical structures configured to diffract visible light. The optical structure has a second refractive index that is greater than the first refractive index.
In a second aspect, an optical element includes a substrate having a first index of refraction and being transparent in the visible spectrum. The optical element also includes a pattern of periodically repeating optical structures formed on the substrate and configured to diffract visible light. The optical structure has a second refractive index greater than the first refractive index and includes a polymer material having an inorganic material incorporated therein.
In a third aspect, an optical system includes an optical element. The optical element includes a substrate having a first index of refraction and being transparent in the visible spectrum. The optical element also includes a pattern of periodically repeating optical structures formed on the substrate and configured to diffract visible light. The optical structure has a second refractive index greater than the first refractive index and includes a polymer material having an inorganic material incorporated therein. The periodically repeating optical structure includes a nanobeam arranged as a super-surface. The super-surface includes a plurality of repeating unit cells, wherein each unit cell includes a first set of nanobeams formed by one or more first nanobeams and a second set of nanobeams formed by one or more second nanobeams disposed adjacent to the one or more first nanobeams and spaced apart from each other by a sub-wavelength interval. The one or more first nanobeams and the plurality of second nanobeams are elongated in different orientation directions.
In a fourth aspect, an optical system includes a waveguide configured to propagate visible light. The optical system includes a substrate having a first index of refraction and being transparent in the visible spectrum such that light can be guided therein by total internal reflection. The optical system also includes a pattern of periodically repeating optical structures formed on the substrate and configured to diffract visible light. The optical structure has a second refractive index greater than the first refractive index and includes a polymer material having an inorganic material incorporated therein. The periodically repeating optical structure is arranged to diffract light at a diffraction angle relative to a direction of incident light and to cause the diffracted light to propagate under total internal reflection in the substrate, or to diffract light guided under total internal reflection within the substrate at a diffraction angle relative to a direction of light guided within the substrate.
In a fifth aspect, a head-mounted display device is configured to project light to an eye of a user to display augmented reality image content. The head mounted display device includes a frame configured to be supported on a head of a user. The head-mounted display device also includes a display disposed on the frame, wherein at least a portion of the display includes one or more waveguides. The one or more waveguides are transparent and are arranged at a location in front of the user's eyes when the head mounted display device is worn by the user such that the transparent portion transmits light from a portion of the environment in front of the user to the user's eyes to provide a view of the portion of the environment in front of the user. The head-mounted display device also includes one or more light sources and at least one diffraction grating configured to couple light from the light sources into or out of the one or more waveguides. The at least one diffraction grating includes a substrate having a first index of refraction and being transparent in the visible spectrum. The at least one diffraction grating additionally includes a pattern of periodically repeating optical structures formed on the substrate and configured to diffract visible light. The optical structure has a second refractive index greater than the first refractive index and includes a polymer material having an inorganic material incorporated therein.
In a sixth aspect, a method of manufacturing an optical element includes: providing a substrate transparent in the visible spectrum; forming a periodically repeating polymer structure having a first refractive index on a substrate; and exposing the substrate to a metal precursor followed by an oxidizing precursor. The exposure is performed under pressure and temperature such that an inorganic material comprising a metal of the metal precursor is incorporated into the periodically repeating polymer structure, thereby increasing the refractive index of the periodically repeating polymer structure to form a pattern of periodically repeating optical structures configured to diffract visible light.
In a seventh aspect, a method of manufacturing an optical element includes: a substrate having a first refractive index and being transparent in the visible spectrum is provided, wherein the substrate has a periodically repeating polymer structure formed thereon. The method additionally includes exposing the substrate to a metal precursor, followed by exposure to an oxidizing precursor. Performing the exposure under pressure and temperature such that an inorganic material comprising a metal of the metal precursor is incorporated into the periodically repeating polymer structure, thereby forming a pattern of periodically repeating optical structures configured to diffract visible light, wherein the optical structures have a second refractive index greater than the first refractive index.
Drawings
Fig. 1 shows a view of Augmented Reality (AR) of a user through an AR device.
Fig. 2 shows an example of a wearable display system.
Fig. 3 illustrates a conventional display system for simulating a three-dimensional image of a user.
FIG. 4 illustrates aspects of a method for simulating a three-dimensional image using multiple depth planes.
Fig. 5A-5C illustrate the relationship between the radius of curvature and the radius of focus.
Fig. 6 shows an example of a waveguide stack for outputting image information to a user.
Fig. 7 shows an example of an outgoing light beam output by a waveguide.
Fig. 8 illustrates an example of a stacked waveguide assembly, wherein each depth plane includes an image formed using a plurality of different component colors.
Fig. 9A illustrates a cross-sectional side view of an example of a set of stacked waveguides, each including an incoupling optical element.
Fig. 9B illustrates a perspective view of an example of the plurality of stacked waveguides of fig. 9A.
Fig. 9C illustrates a top-down plan view of an example of the multiple stacked waveguides of fig. 9A and 9B.
Fig. 10 schematically illustrates a cross-sectional view of an optical element including a periodically repeating polymer-based optical structure having an inorganic material incorporated therein.
Fig. 11 schematically illustrates a method of manufacturing an optical element comprising a periodically repeating polymer-based optical structure having an inorganic material incorporated therein.
Fig. 12A-12C are cross-sectional views of intermediate structures at various stages of providing a periodically repeating base polymer structure using a photolithographic process.
Fig. 13A-13C are cross-sectional views of intermediate structures at various stages in the fabrication of a periodically repeating base polymer structure using a nanoimprint process.
Fig. 14A-14B are cross-sectional views of intermediate structures at various stages in the manufacture of an optical element that includes a periodically repeating polymer-based optical structure having an inorganic material incorporated therein.
Fig. 15A-15B are cross-sectional views of intermediate structures at various stages in the manufacture of an optical element that includes a periodically repeating polymer-based optical structure having an inorganic material incorporated therein.
Fig. 16A-16B are cross-sectional views of intermediate structures at various stages in the manufacture of an optical element that includes a periodically repeating polymer-based optical structure having an inorganic material incorporated therein.
17A-17H illustrate an optical element comprising a plurality of wave plate elements, wherein each wave plate element comprises a pattern of periodically repeating polymer-based optical structures having an inorganic material incorporated therein, illustrating changes in polarization vectors with respect to incident light that correspond to rotations of the wave plate elements at angles θ of 0, π/4, π/2, 3 π/4, π,5 π/4, 3 π/2, and 7 π/4, respectively, on the fast axis.
Figure 18A shows a cross-sectional side view of a diffraction grating having a 2-phase order geometric phase optical element formed from a polymer-based optical structure having an inorganic material incorporated therein.
Figure 18B shows a top view of the diffraction grating of figure 18A.
Figure 19 shows a top view of a diffraction grating having a 4-phase order geometric phase optical element formed from a polymer-based optical structure having an inorganic material incorporated therein.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
Optical systems, such as display systems, often utilize optical elements to control the propagation of light. In some applications, optical elements having reduced dimensions (e.g., thin structures) may be useful due to the need for compact optical systems. Such optical elements may include, for example, diffractive optical elements.
An example diffractive optical element is a diffraction grating for coupling light into a light guide, such as a waveguide. The light guide may have, for example, a diffraction grating disposed thereon or therein that is configured to couple light incident on the light guide (e.g., at normal incidence) into the light guide at an angle such that diffracted light is guided within the light guide by total internal reflection. Diffractive optical elements, such as diffraction gratings, may be included in or on the light guide to couple light guided within the light guide by total internal reflection out of the light guide. The diffractive optical element may also be used to manipulate (e.g., redirect and/or modify) light beams propagating by total internal reflection within the light guide. Methods for manufacturing diffractive optical elements such as those described herein may also be useful, which also provide increased confinement of light within the light guide and/or increased diffraction efficiency.
Such diffractive optical elements may include a pattern of periodically repeating optical structures formed on a substrate and configured to diffract visible light, wherein the optical structures have a refractive index greater than a refractive index of the substrate. The diffractive optical element is formed of a polymer material having an inorganic material incorporated therein. In some cases, the polymeric material may be used as a photoresist that is retained as the final optical structure and may significantly reduce manufacturing complexity. The incorporation of inorganic materials in optical structures potentially allows for versatile tuning of optical properties such as refractive index and mechanical properties such as stiffness. The inorganic materials may be bonded using atomic layer deposition, which may enable precise control of the amount and depth of bonding in the optical structure.
Another approach to providing compact optical elements includes the use of thin films, such as diffraction gratings based on a super surface (metasface) formed from thin film-based nanostructures. Compared to geometric optics, a meta-surface or meta-material surface offers the opportunity to achieve an almost flat, aberration-free optical device on a smaller scale. Without being limited by theory, in some embodiments, the super-surface includes a dense arrangement of surface structures that function as resonant optical antennas. The resonant nature of the light-surface structure interaction provides the ability to manipulate the optical wavefront. In some cases, the super-surface may allow for the use of thin, relatively planar elements formed by simple patterning processes to replace bulky or difficult to manufacture optical components. However, the fabrication of thin film-based optical elements may include patterning of metals or high index dielectric materials by photolithography or nanoimprinting, both of which are expensive and/or difficult to achieve for structures having small dimensions and/or complex shapes.
Advantageously, the polymer-based optical structure having inorganic materials incorporated therein may be configured as a super-surface for forming various optical elements including diffraction gratings. The super-surface may take the form of a grating formed of a plurality of repeating unit cells. Each unit cell may include two or more groups of nanobeams elongated in the cross direction: one or more first nanobeams elongated in a first direction and a plurality of second nanobeams elongated in a second direction different from the first direction.
Some diffractive optical elements, for example, including a super-surface formed by a polymer-based optical structure, may be used in wearable display systems to provide compact optical elements. Augmented reality systems may display virtual content to a user or viewer while still allowing the user to see the world around them. The content may be displayed on a head mounted display, which may be mounted on the head of a viewer. The head mounted display may be, for example, part of eyeglasses and projects image information to the user's eyes. Additionally, the display may also transmit light from the ambient environment to the user's eyes to allow viewing of the ambient environment.
Reference will now be made to the drawings, wherein like reference numerals refer to like parts throughout.
Example display System
Fig. 2 shows one example of a wearable display system 60. The display system 60 includes a display 70 and various mechanical and electronic modules and systems that support the functionality of the display 70. The display 70 may be coupled to a frame 80, the frame 80 being wearable by a display system user or viewer 90 and configured to position the display 70 in front of the eyes of the user 90. In some embodiments, the display 70 may be considered eyewear. In some embodiments, a speaker 100 is coupled to the frame 80 and configured to be positioned near an ear canal of the user 90 (in some embodiments, another speaker, not shown, may optionally be positioned near another ear canal of the user to provide stereo/shapeable sound control). The display system may also include one or more microphones 110 or other devices to detect sound. In some embodiments, the microphone is configured to allow a user to provide input or commands to the system 60 (e.g., select voice menu commands, natural language questions, etc.) and/or may allow audio communication with others (e.g., other users of similar display systems). The microphone may further be configured as a peripheral sensor to collect audio data (e.g., sounds from the user and/or the environment). In some embodiments, the display system may also include peripheral sensors 120a, which may be separate from the frame 80 and attached to the body of the user 90 (e.g., on the head, torso, limbs, etc. of the user 90). In some embodiments, the peripheral sensor 120a may be configured to acquire data characterizing a physiological state of the user 90. For example, the sensor 120a may be an electrode.
With continued reference to fig. 2, the display 70 is operatively coupled to a local data processing module 140 by a communication link 130 (e.g., by a wired or wireless connection), and the local data processing module 140 may be mounted in various configurations, such as fixedly attached to the frame 80, fixedly attached to a helmet or hat worn by the user, embedded in headphones, or otherwise removably attached to the user 90 (e.g., in a backpack configuration, in a strap-coupled configuration). Similarly, sensor 120a may be operatively coupled to local processor and data module 140 by a communication link 120b (e.g., a wired wire or wireless connection). The local processing and data module 140 may include a hardware processor as well as digital memory, such as non-volatile memory (e.g., flash memory or a hard drive), both of which may be used for processing, caching, and storage of auxiliary data. The data includes data a captured from sensors (which may be, for example, operatively coupled to the frame 80 or otherwise attached to the user 90) such as image capture devices (such as cameras), microphones, inertial measurement units, accelerometers, compasses, GPS units, radios, gyroscopes, and/or other sensors disclosed herein); and/or data b) acquired and/or processed using remote processing module 150 and/or remote data store 160 (including data relating to virtual content), which data b) may be used for delivery to display 70 after such processing or retrieval. The local processing and data module 140 may be operatively coupled to the remote processing module 150 and the remote data repository 160 by communication links 170, 180 (e.g., via wired or wireless communication links) such that these remote modules 150, 160 are operatively coupled to each other and available as resources to the local processing and data module 140. In some embodiments, the local processing and data module 140 may include one or more of an image capture device, a microphone, an inertial measurement unit, an accelerometer, a compass, a GPS unit, a radio, and/or a gyroscope. In some other embodiments, one or more of these sensors may be attached to the frame 80, or may be a stand-alone structure that communicates with the local processing and data module 140 through a wired or wireless communication path.
With continued reference to fig. 2, in some embodiments, the remote processing module 150 may include one or more processors configured to analyze and process data and/or image information. In some embodiments, the remote data repository 160 may include a digital data storage facility, which may be available through the internet or other network configuration in a "cloud" resource configuration. In some embodiments, the remote data repository 160 may include one or more remote servers that provide information, such as information used to generate augmented reality content, to the local processing and data module 140 and/or the remote processing module 150. In some embodiments, all data is stored and all computations are performed in local processing and data modules, allowing fully autonomous use from remote modules.
Referring now to fig. 3, by providing a slightly different presentation of the image to each eye of the viewer, it may be achieved that the image is perceived as "three-dimensional" or "3-D". Fig. 3 illustrates a conventional display system for simulating a three-dimensional image for a user. Two different images 190, 200 are output to the user, one for each
However, it can be appreciated that the human visual system is more complex and providing a true depth perception is more challenging. For example, many viewers of conventional "3-D" display systems find such systems uncomfortable or not at all feeling of depth. Without being limited by theory, it is believed that a viewer of an object may perceive the object as "three-dimensional" due to a combination of vergence and accommodation. Vergence movement of the two eyes relative to each other (i.e., rotation of the eyes such that the pupils move toward or away from each other to converge the line of sight of the eyes, thereby gazing at the object) is closely related to the focusing (or "accommodation") of the lenses and pupils of the eyes. Under normal circumstances, changing the focal length of the lens of the eye or adapting the eye to change the focus from one object to another object at different distances, in a relationship known as "accommodation-vergence reflex" and pupil dilation or constriction, will automatically result in a change in the matching of vergences to the same distance. Also, under normal conditions, changes in vergence will trigger adaptive matching changes in lens shape and pupil size. As described herein, many stereoscopic or "3-D" display systems display a scene to each eye using slightly different presentations (and thus slightly different images) so that the human visual system perceives three-dimensional perspective. However, such systems are uncomfortable for many viewers, since they simply provide different presentations of the scene, among other directions, but the eye views all image information in a single state of accommodation and violates the "accommodation-vergence reflection". A display system that provides a better match between accommodation and vergence may result in a more realistic and comfortable simulation of a three-dimensional image.
FIG. 4 illustrates aspects of a method for simulating a three-dimensional image using multiple depth planes. Referring to fig. 4, objects at different distances from the
The distance between an object and an
Without being limited by theory, it is believed that the human eye can typically interpret a limited number of depth planes to provide depth perception. Thus, by providing the eye with different presentations of the image corresponding to each of these limited number of depth planes, a highly reliable simulation of perceived depth may be achieved. The different presentations may be focused separately by the eyes of the viewer, helping to provide depth cues to the user based on eye accommodation required to focus different image features of a scene located on different depth planes and/or based on observing different image features on different depth planes located out of focus.
Fig. 6 shows an example of a waveguide stack for outputting image information to a user. The
With continued reference to fig. 6, the
In some embodiments, the
In some embodiments, the light injected into the
In some embodiments, the
The
With continued reference to fig. 6, the
With continued reference to fig. 6, as discussed herein, each
The
In some embodiments, two or more of the
With continued reference to fig. 6, the out-coupling
In some embodiments, the outcoupling
In some embodiments, one or more DOEs may be switched between an "on" state in which they actively diffract and an "off" state in which they do not significantly diffract. For example, a switchable DOE may comprise a polymer dispersed liquid crystal layer, wherein the droplets comprise a diffraction pattern in a host medium, the refractive index of the droplets may be switched to substantially match the refractive index of the host material (in which case the pattern DOEs not significantly diffract incident light), or the droplets may be switched to a refractive index that DOEs not match the refractive index of the host medium (in which case the pattern actively diffracts incident light).
In some embodiments, a camera component 630 (e.g., a digital camera, including visible and infrared light cameras) may be provided to capture images of the
Referring now to fig. 7, an example of an outgoing beam output by a waveguide is shown. One waveguide is shown, but it is understood that other waveguides in the waveguide assembly 260 (fig. 6) may function similarly, where the
In some embodiments, a full color image may be formed at each depth plane by overlaying an image of each of the component colors (e.g., three or more component colors). Fig. 8 illustrates an example of a stacked waveguide assembly, wherein each depth plane includes an image formed using a plurality of different component colors. The illustrated embodiment shows depth planes 240a-240f, although greater or lesser depths are also contemplated. Each depth plane may have three or more component color images associated therewith, including: a first image of a first color, G; a second image of a second color, R; and a third image of a third color, B. The different depth planes are represented in the figure by different numbers of diopters (dpt) behind the letters G, R and B. By way of example only, the numbers following each of these letters indicate the reciprocal of the diopter (1/m) or depth plane distance from the viewer, and each box in the figure represents a separate component color image. In some embodiments, the exact placement of the depth planes for the different component colors may vary to account for differences in the focusing of the eye on light of different wavelengths. For example, different component color images for a given depth plane may be disposed on the depth plane corresponding to different distances from the user. Such an arrangement may increase visual acuity and user comfort and/or may reduce color differences.
In some embodiments, light of each component color may be output by a single dedicated waveguide, and thus, each depth plane may have multiple waveguides associated therewith. In such embodiments, each box in the figure including the letter G, R or B may be understood to represent a separate waveguide, and three waveguides may be provided for each depth plane, with three component color images provided for each depth plane. Although the waveguides associated with each depth plane are shown adjacent to one another in this figure for ease of description, it will be understood that in a physical arrangement, the waveguides may all be arranged in a stack, one waveguide at each level. In some other embodiments, multiple component colors may be output by the same waveguide, such that, for example, each depth plane may provide only a single waveguide.
With continued reference to fig. 8, in some embodiments, G is green, R is red, and B is blue. In some other embodiments, other colors associated with other wavelengths of light may be used instead of, in addition to, or in addition to, one or more of red, green, or blue, including magenta and cyan.
It will be understood that in the present disclosure, reference to light of a given color will be understood to encompass light of one or more wavelengths within the range of wavelengths that the viewer perceives as having light of that given color. For example, red light may include light at one or more wavelengths in the range of about 620-780nm, green light may include light at one or more wavelengths in the range of about 492-577nm, and blue light may include light at one or more wavelengths in the range of about 435-493 nm.
In some embodiments, light source 530 (fig. 6) may be configured to emit light at one or more wavelengths outside the visual perception range of the viewer, such as infrared and/or ultraviolet wavelengths. In addition, the incoupling, outcoupling, and other light redirecting structures of the waveguide of
Referring now to fig. 9A, in some embodiments, light incident on the waveguide may need to be redirected to couple the light into the waveguide. The incoupling optical elements can be used to redirect and incouple light into their respective waveguides. Fig. 9A shows a cross-sectional side view of an example of a plurality or set 660 of stacked waveguides, each including an incoupling optical element. The waveguides may each be configured to output light of one or more different wavelengths, or light of one or more different wavelength ranges. It should be understood that the stack 660 may correspond to the stack 260 (fig. 6), and that example waveguides of the stack 660 may correspond to portions of the plurality of
Exemplary stacked waveguide group 660 includes waveguides 670, 680, and 690. Each waveguide includes associated incoupling optical elements (which may also be referred to as light input regions on the waveguide), such as incoupling optical element 700 disposed on a major surface (e.g., an upper major surface) of waveguide 670, incoupling optical element 710 disposed on a major surface (e.g., an upper major surface) of waveguide 680, and incoupling optical element 720 disposed on a major surface (e.g., an upper major surface) of waveguide 690. In some embodiments, one or more of the incoupling optical elements 700, 710, 720 may be disposed on the bottom major surface of the respective waveguide 670, 680, 690 (particularly where the one or more incoupling optical elements are reflective, deflecting optical elements). As an example, the incoupling optical elements 700, 710, 720 may be disposed on the upper major surface of their respective waveguide 670, 680, 690 (or on top of the next lower waveguide), particularly if the incoupling optical elements are transmissive, deflecting optical elements. In some embodiments, the incoupling optical elements 700, 710, 720 may be disposed in the bulk of the respective waveguides 670, 680, 690. In some embodiments, the incoupling optical elements 700, 710, 720 are wavelength selective, such that they selectively redirect light of one or more wavelengths while transmitting light of other wavelengths, as discussed herein. Although shown on one side or corner of their respective waveguides 670, 680, 690, it should be understood that in some embodiments, incoupling optical elements 700, 710, 720 may be disposed in other regions of their respective waveguides 670, 680, 690.
As illustrated, the incoupling optical elements 700, 710, 720 may be laterally offset from one another. In some embodiments, each incoupling optical element may be offset so that it receives light without passing through another incoupling optical element. For example, each incoupling optical element 700, 710, 720 may be configured to receive light from a different
Each waveguide also includes associated light distribution elements, such as light distribution element 730 disposed on a major surface (e.g., top major surface) of waveguide 670, light distribution element 740 disposed on a major surface (e.g., top major surface) of waveguide 680, and light distribution element 750 disposed on a major surface (e.g., top major surface) of waveguide 690. In some other embodiments, light distribution elements 730, 740, 750 may be disposed on the bottom major surface of associated waveguides 670, 680, 690, respectively. In some other embodiments, light distribution elements 730, 740, 750 may be provided on both the top and bottom major surfaces of associated waveguides 670, 680, 690, respectively; or light distribution elements 730, 740, 750 may be arranged on different ones of the top and bottom main surfaces, respectively, of different associated waveguides 670, 680, 690.
The waveguides 670, 680, 690 may be spaced apart and separated by layers of, for example, gas, liquid, and/or solid material. For example, as illustrated, layer 760a may separate waveguides 670 and 680; and layer 760b may separate waveguides 680 and 690. In some embodiments, layers 760a and 760b are formed of a low index material (i.e., a material having a lower index of refraction than the material forming the immediately adjacent one of waveguides 670, 680, 690). Preferably, the refractive index of the material forming layers 760a, 760b is 0.05 or more less, or 0.10 less, than the refractive index of the material forming waveguides 670, 680, 690. Advantageously, the lower index layers 760a, 760b may act as cladding layers that promote Total Internal Reflection (TIR) of light through the waveguides 670, 680, 690 (e.g., between the top and bottom major surfaces of each waveguide). In some embodiments, the layers 760a, 760b are formed of air. Although not shown, it will be understood that the top and bottom of the exemplary waveguide set 660 may include immediately adjacent cladding layers.
Preferably, the materials forming waveguides 670, 680, 690 are similar or the same, and the materials forming layers 760a, 760b are similar or the same, for ease of manufacturing and other considerations. In some embodiments, the materials forming waveguides 670, 680, 690 may be different between one or more waveguides, and/or the materials forming layers 760a, 760b may be different, while still maintaining the various refractive index relationships described above.
With continued reference to fig. 9A, light rays 770, 780, 790 are incident on waveguide set 660. It should be appreciated that the light rays 770, 780, 790 may be injected into the waveguides 670, 680, 690 by one or more
In some embodiments, the light rays 770, 780, 790 have different characteristics, e.g., different wavelengths or different wavelength ranges, which may correspond to different colors. The incoupling optical elements 700, 710, 720 each deflect incident light so that the light propagates through a respective one of the waveguides 670, 680, 690 by TIR. In some embodiments, the incoupling optical elements 700, 122, 720 each selectively deflect light of one or more particular wavelengths while transmitting other wavelengths to the underlying waveguide and associated incoupling optical elements.
For example, the incoupling optical element 700 may be configured to deflect light 770 having a first wavelength or wavelength range, while transmitting light 780 and 790 having different second and third wavelengths or wavelength ranges, respectively. The transmitted light 780 is then incident on and deflected by the incoupling optical elements 710, which incoupling optical elements 710 are configured to selectively deflect light of a second wavelength or wavelength range. The light 790 is deflected by the incoupling optical element 720, and the incoupling optical element 720 is configured to selectively deflect light of a third wavelength or wavelength range.
With continued reference to fig. 9A, deflected light rays 770, 780, 790 are deflected such that they propagate through respective waveguides 670, 680, 690; that is, the incoupling optical elements 700, 710, 720 of each waveguide deflect light into the corresponding waveguide 670, 680, 690 to couple the light into the corresponding waveguide. Light rays 770, 780, 790 are deflected at an angle that causes the light to propagate through the respective waveguides 670, 680, 690 by TIR. Light rays 770, 780, 790 propagate through the respective waveguide 670, 680, 690 by TIR until they are incident on the respective light distribution element 730, 740, 750 of the waveguide.
Referring now to fig. 9B, a perspective view of an example of the multiple stacked waveguides of fig. 9A is shown. As described above, the coupled-in light rays 770, 780, 790 are deflected by the coupled-in optical elements 700, 710, 720, respectively, and then propagate by TIR within the waveguides 670, 680, 690, respectively. Light rays 770, 780, 790 are then incident on light distribution elements 730, 740, 750, respectively. The light distribution elements 730, 740, 750 deflect the light rays 770, 780, 790 such that they propagate towards the out-coupling optical elements 800, 810, 820, respectively.
In some embodiments, the light distribution elements 730, 740, 750 are Orthogonal Pupil Expanders (OPE). In some embodiments, the OPE deflects or distributes light to the outcoupling optical elements 800, 810, 820, and in some embodiments, also increases the beam or spot size of the light as it propagates to the outcoupling optical elements. In some embodiments, the light distribution elements 730, 740, 750 may be omitted, and the incoupling optical elements 700, 710, 720 may be configured to deflect light directly into the outcoupling optical elements 800, 810, 820. For example, referring to fig. 9A, the light distribution elements 730, 740, 750 may be replaced by out-coupling optical elements 800, 810, 820, respectively. In some embodiments, the out-coupling optical elements 800, 810, 820 are Exit Pupils (EP) or Exit Pupil Expanders (EPE) that direct light into the viewer's eye 210 (fig. 7). It should be understood that the OPE may be configured to increase the size of the eye box in at least one axis, and the EPE may increase the eye box in an axis, e.g., orthogonal to the axis of the OPE. For example, each OPE may be configured to redirect a portion of incident (strike) OPE light to an EPE of the same waveguide while allowing the remainder of the light to continue propagating down the waveguide. After re-incidence of the OPE, another portion of the remaining light is redirected to the EPE, and the remaining portion of that portion continues to propagate further down the waveguide, and so on. Similarly, after incidence of the EPE, a portion of the incident light is directed out of the waveguide toward the user, and the remainder of the light continues to propagate through the waveguide until it again impinges the EP, at which point another portion of the incident light is directed out of the waveguide, and so on. Thus, each time a portion of the light is redirected by an OPE or EPE, a single beam of incoupled light can be "replicated" to form a field that clones the light beam, as shown in fig. 6. In some embodiments, the OPE and/or EPE may be configured to modify the size of the light beam.
Thus, referring to fig. 9A and 9B, in some embodiments, waveguide set 660 includes waveguides 670, 680, 690; coupling optical elements 700, 710, 720; light distribution elements (e.g. OPE)730, 740, 750; and an outcoupling optical element (e.g., EP)800, 810, 820 for each component color. The waveguides 670, 680, 690 may be stacked with an air gap/cladding between each waveguide. The incoupling optical elements 700, 710, 720 redirect or deflect incident light (with different incoupling optical elements receiving different wavelengths of light) into their waveguides. The light then propagates at an angle that will result in TIR within the respective waveguide 670, 680, 690. In the example shown, light 770 (e.g. blue light) is deflected by the first incoupling optical element 700 and then continues to be reflected along the waveguide to interact with the light distribution element (e.g. OPE)730 and then the outcoupling optical element (e.g. EP)800 in the manner described previously. Light rays 780 and 790 (e.g., green and red, respectively) will pass through waveguide 670 and light ray 780 is incident on and deflected by incoupling optical element 710. Light ray 780 then reflects via TIR along waveguide 680, proceeds to its light distribution element (e.g., OPE)740, and then proceeds to out-coupling optical element (e.g., EP) 810. Finally, light ray 790 (e.g., red light) passes through waveguide 690 to be incident on light incoupling optical element 720 of waveguide 690. The light incoupling optical element 720 deflects the light 790 such that the light propagates by TIR to the light distribution element (e.g., OPE)750 and then to the outcoupling optical element (e.g., EP) 820. The out-coupling optical element 820 then finally out-couples the light 790 to a viewer, who also receives the out-coupled light from the other waveguides 670, 680.
Fig. 9C illustrates a top-down plan view of an example of the multiple stacked waveguides of fig. 9A and 9B. As illustrated, the waveguides 670, 680, 690 together with each waveguide's associated light distribution element 730, 740, 750 and associated outcoupling optical element 800, 810, 820 may be vertically aligned. However, as discussed herein, the incoupling optical elements 700, 710, 720 are not vertically aligned; in contrast, the incoupling optical elements are preferably non-overlapping (e.g., laterally spaced apart, as seen in a top-down view). As discussed further herein, this non-overlapping spatial arrangement facilitates one-to-one injection of light from different sources into different waveguides, thereby allowing a particular light source to be uniquely coupled to a particular waveguide. In some embodiments, arrangements including non-overlapping spatially separated incoupling optical elements may be referred to as shifted pupil systems, and the incoupling optical elements within these arrangements may correspond to sub-pupils.
Optical element formed from polymer-based optical structure incorporating inorganic material
Display systems may employ various optical elements to control the propagation of light. However, in some cases, such as display systems including head-mounted display devices (e.g., display system 80 described above with reference to fig. 2), conventional optical elements may not be ideal or suitable due to their relatively heavy weight, large size, manufacturing challenges, and/or insufficient optical properties (e.g., diffraction angle and diffraction efficiency).
For example, as described above with reference to fig. 9A-9C, the display system may include optical elements (e.g., incoupling optical elements, light distribution elements, and outcoupling optical elements), which may include diffraction gratings. Furthermore, as described further above with reference to fig. 9A-9C, light coupled into a respective waveguide may propagate within the waveguide by Total Internal Reflection (TIR). To achieve TIR, it may be desirable for the diffraction grating to have a relatively high diffraction angle with respect to the surface normal. In addition, high diffraction efficiency may be desirable to increase light intensity and image brightness. However, providing a diffraction grating capable of achieving high diffraction angles and high diffraction efficiencies for visible light presents challenges. To meet these and other needs, examples of optical elements disclosed herein, such as diffraction gratings, may utilize optical elements formed from periodically repeating polymer-based optical structures having inorganic materials incorporated therein.
Fig. 10 illustrates a cross-sectional view of an optical element (e.g., a diffraction grating 1000) including a periodically repeating polymer-based optical structure having an inorganic material incorporated therein, in accordance with various embodiments. The diffraction grating 1000 includes a grating having a first index of refraction (n)1) And a
According to an embodiment, the
According to an embodiment, the
The pattern of periodically repeating
Still referring to FIG. 10, according to various embodiments, the
The particular polymer may be selected based on, among other factors, the deposition chemistry used to form the inorganic material to be incorporated into the base polymer material. For example, in various embodiments, the polymer chains of the base polymer units can include various functional groups, such as carbonyl groups, hydroxyl groups, and pyridyl groups, which are suitable for reaction with metal precursors that can be used to form inorganic materials, as will be described in further detail below. As an example, when the deposition chemistry includes Al (CH)3)3(TMA) as Metal precursor and H2O as an oxidizing precursor for Al formation2O3When so, PMMA may be included in the polymeric material such that the carbonyl groups of PMMA may react with TMA to form Al-OH species, and then with H in a hydrolysis reaction2Reaction of O to form Al2O3. Other examples are described in more detail below.
In various embodiments, the base polymer may be photosensitive or photoreactive. The base polymer may include or be used as a photoresist. In some embodiments, the photoresist may be a positive resist, wherein portions exposed to light become soluble in a photoresist developer, while unexposed portions remain insoluble in the photoresist developer. In some other embodiments, the photoresist may be a negative photoresist, wherein the portions of the photoresist exposed to light become insoluble to a photoresist developer, while the unexposed portions are dissolved by the photoresist developer.
In some embodiments, when included, the photoresist in the base polymer may be a photopolymerizable photoresist, which may include, for example, an allyl monomer configured to generate free radicals when exposed to light, which in turn initiates photopolymerization of the monomer to generate the polymer. When configured as a negative resist, the photopolymerizable photoresist may comprise, for example, methyl methacrylate. When included, in some other embodiments, the photoresist in the base polymer may be a photodecomposed photoresist configured to generate hydrophilic products under light. When configured as a positive resist, the photodecomposable photoresist can include, for example, azidoquinone (azidoquinone), such as N-Dimethylbenzoquinone (DQ). When included, in some other embodiments, the photoresist in the base polymer can be a photocrosslinked photoresist configured to crosslink chain-by-chain to create an insoluble network when exposed to light.
Still referring to FIG. 10, according to various embodiments, the inorganic material incorporated into the
As described herein, when the inorganic material includes an oxide, it may be stoichiometric or sub-stoichiometric. For example, the alumina may be a stoichiometric form of Al2O3AlO, which may also be in substoichiometric formxWherein x is less than 1.5 stoichiometric.Additionally, as described herein, oxides of metals may include other metals. For example, aluminum oxide may be included as aluminum hafnate (AlHfO)x) A part of (a). Thus, the material may comprise two different metals.
According to embodiments, the inorganic material may be selected based on its bulk refractive index. The refractive index of the inorganic material may be higher than the refractive index of the substrate. The refractive index of the inorganic material may be, for example, greater than 1.7, 2.0, 2.3, 2.6, 3.0, or have values within or may be outside of the ranges defined by these values. In some embodiments, the inorganic material may be a stoichiometric material selected based on its bulk refractive index. For example, the inorganic material can be stoichiometric aluminum oxide having a refractive index of 1.66, stoichiometric zinc oxide having a refractive index of 1.95, stoichiometric zirconium oxide having a refractive index of 1.95, stoichiometric hafnium oxide having a refractive index of 2.09, stoichiometric titanium oxide having a refractive index of 2.35, or combinations thereof, to name a few. In some other embodiments, the inorganic material may be a sub-stoichiometric inorganic material having a refractive index greater than the refractive index of the corresponding stoichiometric inorganic material. For example, by reducing the oxygen content, the refractive index of the metal oxide can be increased by 2%, 5%, 10%, 20%, or 30%, or any percentage within any range defined by these values. In some other embodiments, the inorganic material may be a mixture of inorganic materials having refractive indices between the refractive indices of the constituent inorganic materials. For example, the refractive index of the ternary metal oxide can be adjusted to be between that of the component binary metal oxide by adjusting the relative fractions.
In some embodiments, the
The base polymer material of the
According to embodiments, the
In some embodiments,
The diffraction grating 1000 has
However, as explained in detail below, other embodiments are possible. In other embodiments, adjacent ones of the periodically repeating
Method for manufacturing an optical element formed by a polymer-based optical structure in which an inorganic material is incorporated
In the following, a method of manufacturing a polymer-based optical element comprising a polymer-based optical structure, e.g. a diffraction grating 1000 (fig. 10), having inorganic material incorporated therein is described. Referring to fig. 11, a method 1100 includes providing 1104 a substrate having a first index of refraction and being transparent in the visible spectrum. The method also includes forming 1108 a periodically repeating base polymer structure on the substrate. The method also includes exposing 1112 the substrate to a metal precursor and then to an oxidizing precursor. Exposing the substrate is performed under pressure and temperature such that an inorganic material comprising a metal is incorporated into the periodically repeating base polymer structures, thereby forming a pattern of periodically repeating optical structures configured to diffract visible light, wherein the optical structures have a second refractive index that is greater than the first refractive index.
Referring to fig. 11, a substrate 1104 having a first index of refraction and being transparent in the visible spectrum is provided. This may include, for example, providing a
Still referring to fig. 11, a base polymer structure is formed 1108 that repeats periodically over the substrate. As described below, the polymer structure may be formed using a suitable process including, for example, a photolithographic process (fig. 12A-12C) or a nanoimprint process (fig. 13A-13C). In some embodiments, as described with respect to fig. 12A-12C, forming 1108 a periodically repeating optical structure on a substrate may be performed by depositing a suitable polymer material as described above with respect to fig. 10 and then patterning using a photolithography and etching process. In some other embodiments, as described with respect to fig. 13A-13C, forming 1108 a periodically repeating optical structure on a substrate can be performed by depositing a suitable polymer material as described above with respect to fig. 10 and then patterning using a nanoimprint technique.
12A-12C illustrate cross-sectional views of
In some embodiments, the
Depending on the design, the
Referring to
Exposure to light 1212 (e.g., coherent UV light or electron beam) causes a chemical change, e.g., a polymeric crosslink in the base polymer layer 1208 (e.g., comprising photoresist), which allows selectively removing exposed portions of the
Referring to the intermediate structure 1200C of fig. 12C, after selective removal, the resulting periodically repeating
Fig. 13A-13C show cross-sectional views of intermediate structures 1300A-1300C, respectively, at various stages of fabrication of a periodically repeating base polymer structure using a nanoimprint process. In the example shown, the method of forming intermediate structure 1300A is similar to the method of forming
Referring to the
Referring again to fig. 11, the method of making a polymer optical element incorporating an inorganic material further includes exposing 1112 the substrate to a metal precursor and then to an oxidizing precursor, wherein exposing the substrate is performed under pressure and temperature such that the inorganic material including the metal is incorporated into the periodically repeating base polymer structure, thereby forming a pattern of periodically repeating optical structures configured to diffract visible light, wherein the optical structures have a second refractive index greater than the first refractive index. In the following, with reference to fig. 14A-14B, 15A-15B, and 16A-16C, different ways of exposing the substrate to incorporate inorganic materials into the periodically repeating base polymer structure are described.
Fig. 14A shows an
Some of the process features used in Atomic Layer Deposition (ALD) can be used to incorporate inorganic materials into the periodically repeating base polymer structure 1204 (fig. 12A) to form the periodically repeating optical structure 1008 (fig. 12B). In some aspects, ALD may be considered to include a type of Chemical Vapor Deposition (CVD) process with self-limiting growth that is controlled by apportioning the chemical reaction into two separate half-reactions included in a growth cycle. For ALD toolsThe growth cycle of the process may include four phases: (1) for example, exposure of a first precursor of a metal precursor; (2) purging (purge) the reaction chamber; (3) exposure of a second precursor, such as an oxidizing precursor; (4) the reaction chamber was further purged. In a first stage of the ALD process, a first precursor reacts with sites on the substrate to form all or part of a molecular layer of the first precursor. In the second stage, for example, argon or N may be used2To reduce, prevent or minimize gas phase reactions that may occur between the remaining first precursor and the subsequently introduced second precursor, which may prevent layer-by-layer growth of molecules. In a third stage, a second precursor is introduced into the purged chamber to react with the molecular layer of the first precursor to produce a monolayer or sub-monolayer of the target material. The fourth stage includes purging/pumping out the residue of the second precursor in preparation for another growth cycle, and the process may be repeated until the desired thickness is reached.
As described above with respect to FIG. 10, the inorganic material incorporated into the
Advantageously, the use of an ALD process for bonding inorganic materials has many advantages. For example, since adsorption, chemisorption, or reaction of the precursors provides control over the amount of material deposited at the monolayer or submonolayer level, the film thickness or the amount of material deposited can be precisely controlled based on the number of reaction cycles. In addition, ALD may be a suitable method for depositing conformal thin films on three-dimensional surfaces because precursors in the vapor phase may reach surfaces that are difficult or inaccessible using other deposition techniques, such as Physical Vapor Deposition (PVD) or Plasma Enhanced Chemical Vapor Deposition (PECVD) depending on line of sight and/or aspect ratio. Furthermore, because adsorption, chemisorption, or reaction can occur at relatively low temperatures (e.g., less than 100 ℃), ALD may be suitable for deposition on structures or surfaces having limited thermal budgets or tolerances.
Thus, in a preferred embodiment, an inorganic material can be incorporated into the periodically repeating
Certain combinations of pressure, temperature, and time may be particularly suitable for forming the
Referring back to fig. 11, according to an embodiment, the exposing 1112 is performed at a pressure greater than atmospheric pressure. Without being bound by any theory, the higher pressure may enhance diffusion of the precursor prior to reacting to form the inorganic material and/or enhance diffusion of the inorganic material after formation. One or both of the total and partial pressures may be adjusted or optimized during exposure to the metal and/or the oxidizing precursor. In various instances, the total pressure during the exposure can be between about 10mTorr and about 100Torr, between about 50mTorr and about 50Torr, between about 100mTorr and about 10Torr, or any pressure within a range defined by these values or outside of these ranges, such as between about 800mTorr and about 5Torr or between 1Torr and 5 Torr. At total pressure, the partial pressure of the precursor can be 2%, 5%, 10%, 20%, 50% of the total pressure or any pressure within or outside the range defined by these values, such as an example of about 25 to 50 mTorr. The remaining partial pressure may be provided by one or more gases other than the precursorProviding, e.g. inert gases, e.g. argon and/or N2。
During the purging process, the total pressure may be maintained the same as or different from the total pressure during exposure to the precursor as described above.
Depending on the method, the exposing 1112 can include exposing the periodically repeating
During purging, the purging time may be equal to or longer than the exposure time to the precursor described above, for example longer than 2x, 5x or 10x or any time within the range defined by these values. The purge time may also be outside of these ranges. Thus, the sub-period t1、t2、t3And t4May have a combination of the above durations, e.g., t1、t31-100 seconds or any range described above and t2、t45-500 seconds or any of the ranges above, wherein the sub-period t1、t2、t3And t4Corresponding to the exposure of the substrate toA first exposure time for purging the metal precursor, a first purge time for purging the metal precursor, a second exposure time for exposing the substrate to the oxidizing precursor, and a second purge time for purging the oxidizing precursor.
Depending on the construction and/or method of manufacture, the exposing 1112 includes exposing the periodically repeating base polymer structure to one or both of a metal precursor and an oxidizing precursor at a temperature of less than about 100 degrees celsius. Relatively low temperatures may be employed to achieve the desired diffusion depth of the precursor and/or inorganic material, as increased pressure and longer exposure times may compensate for the lower temperatures. According to embodiments, the exposing may be performed at a temperature below 200 ℃, 150 ℃, 100 ℃, 80 ℃, 60 ℃,40 ℃ or 20 ℃ or at a temperature within any range defined by these values. Temperatures outside these ranges may be used, including temperatures above 100 ℃.
Exposing the substrate to the metal precursor may include exposing to a precursor comprising a transition metal, such as selected from the group consisting of aluminum, zinc, zirconium, hafnium, and titanium. For example, to incorporate transition metal oxides, including aluminum oxide, zinc oxide, zirconium oxide, hafnium oxide, titanium oxide, tantalum oxide, and combinations thereof, the metal precursors used in the first stage can include halides (i.e., metals bonded to F, Cl, Br, or I), alkyls, and alkoxides with the transition metal.
Depending on the desired structure and/or process, the metal halide precursor may include aluminum chloride or iodide, zinc chloride or iodide, zirconium chloride or iodide, hafnium chloride or iodide, titanium chloride or iodide, or tantalum chloride or iodide.
Depending on the desired structure and/or process, the metal precursor having oxygen bonded to the metal may include an alkoxide (M- (O-CR) n), such as hafnium tert-butoxide Hf (OC)4H9)4Wherein each alkoxy ligand is bonded to the metal atom through an O atom, and β -diketone complex (M ═ O (O))2C3R3)nFor example Zr (thd)4Wherein each diketone ligand is bonded to the metal by two metal-oxygen bonds (ligand "chelationA "metal center).
Depending on the desired structure and/or method, precursors having metal-bonded nitrogen can include metal alkylamides (M (NR)2)n) For example hafnium dimethylamide, Hf (N (CH)3)2)4And metal amidinates (M (N)2CR3)n)。
Organometallic precursors having metal atoms directly bonded to carbon may also be used. Such organometallic precursors may include: alkyl radical M (C)xHy)nFor example trimethylaluminum, Al (CH)3)3(ii) a Cyclopentadienyl, e.g. dicyclopentadienyl hafnium dimethyl, Hf (C)5H5)2(CH3)2(Mixed ligand precursor). Other precursors may be used.
Depending on the desired structure and/or method, exposing the substrate to the oxidizing precursor may include exposing to a composition comprising oxygen (O, O)2) Ozone (O)3) Water (H)2O), hydrogen peroxide (H)2O2) Nitrogen oxides (NO, N)2O), ammonia (NH)4) Or a combination thereof, according to an embodiment. Other precursors, such as other oxidizing precursors, may be used.
Combinations of different precursors can be used and can depend on which inorganic material is incorporated into the periodically repeating
In addition, as described above with respect to fig. 10, the polymer chain of the base polymer unit may include various functional groups, such as carbonyl groups, hydroxyl groups, and pyridyl groups, which are configured to react with a particular metal precursor to form an inorganic material. To provide aIllustrative examples when depositing the chemical species include forming Al2O3Al (CH)3)3(TMA) and H2O, PMMA may then be included in the polymeric base material such that the carbonyl groups of PMMA may react with TMA to form Al-OH species, which in turn react with H in a hydrolysis reaction2O reacts to form Al2O3Of the Al2O3Is incorporated into
Referring to fig. 14A and 14B, based on the foregoing, various parameters, including exposure time, purge time, total or partial pressure, and substrate temperature, may be selected to control diffusion of the precursor and/or inorganic material to form an
In addition, the diffusion of the precursor and/or inorganic material may be controlled such that the width, depth, or thickness (H) of the
However, the configuration is not so limited, and in some other configurations, substantially all of the volume of periodically repeating
As described above, the one or more exposure conditions affect the diffusion characteristics of the precursor and/or the inorganic material. Without being bound by any theory, in some embodiments, at least some of the precursors are diffused into the
However, the configuration is not limited thereto. Without being bound by any theory, in some other embodiments, at least a portion of the inorganic material diffuses into the
Still referring to fig. 14A and 14B, advantageously, the base polymer material forming the periodically repeating
According to some embodiments, the inorganic material is incorporated or infiltrated into the
In the foregoing, exemplary methods and apparatus are described in which inorganic materials are incorporated or infiltrated into the periodically repeating
According to various embodiments, the inorganic material is advantageously bonded by exposing the substrate to a metal precursor and an oxidizing precursor selectively relative to an exposed surface of the base polymer material of the exposed surface of the substrate. This is because, as described above, unlike the surface of the periodically repeating
In the illustrated embodiment of fig. 14A and 14B, when the periodically repeating
According to an alternative embodiment, a method of incorporating an inorganic material into a periodically repeating base polymer structure 1204 (fig. 15A, 16A) to form a periodically repeating optical structure 1008 (fig. 15B, 16A) is described with reference to
In some embodiments, as shown in fig. 15A, the layer of polymer material 1504 formed on the substrate surface in the
In some other embodiments, as shown in FIG. 16A,
Advantageously, incorporating inorganic materials into
Advantageously, incorporating inorganic materials into the
Although specific oxides and nitrides are disclosed herein as including inorganic materials, other materials are possible. In addition, oxides and nitrides may be formed by oxidation processes such as those described herein or by other types of oxidation processes. Other materials may also be formed by oxidation processes. Other types of processes may also be used.
Geometric phase-hyper-surface based optical element comprising polymer based optical structure incorporating inorganic material Piece
The super-surface may comprise surface structures capable of locally altering the polarization, phase and/or amplitude of light in reflection or transmission. The super-surface may include an array of sub-wavelength sized and/or sub-wavelength spaced phase-shifting elements, the pattern of which is configured to control the wavefront of the light such that various optical functions may be derived therefrom, including beam shaping, lensing, beam bending, and polarization splitting. Factors that may be used to manipulate the wavefront of light include the material, size, geometry, and orientation of the surface structure. By arranging surface structures with different scattering properties on the surface, a spatially varying super-surface can be generated, over which the optical wavefront can be substantially manipulated.
In conventional optical elements such as lenses and waveplates, the wavefront is controlled by the propagation phase in a medium much thicker than the wavelength. Unlike conventional optical elements, the meta-surface uses a sub-wavelength sized resonator as a phase shifting element to induce a phase change in light. Because the super-surface is formed of relatively thin and uniform thickness features, the super-surface can be patterned across the surface using thin film processing techniques such as semiconductor processing techniques and direct printing techniques such as nanoimprint techniques.
As discussed above, polymeric optical elements incorporating inorganic materials are relatively easy to manufacture while providing tunable refractive index and stiffness. As a result, polymeric optical elements incorporating inorganic materials are excellent candidates for use in super-surface based optical elements. In the following optical elements (e.g. diffraction gratings), a description is given of a super-surface based formed by a polymer based optical structure incorporating an inorganic material.
Without being bound by any theory, when a beam is incident along a closed period in the space of polarization states of light, it can acquire a dynamic phase from the accumulated path length as well as from the geometric phase. The dynamic phase obtained from the geometric phase is due to local variations in polarization. Some optical elements that are based on geometric phase to form the desired phase front may be referred to as Pancharatnam-Berry phase optical elements (PBOE). The PBOE may be formed of a waveplate element whose fast axis orientation depends on the spatial position of the waveplate element.
Without being limited by theory, by forming the metasurface with a half-wave plate formed from a geometric phase optical element (e.g., a PBOE whose fast axis orientation is formed according to a function θ (x, y)), the incident circularly polarized beam can be completely transformed to have a phase equal to φgAn inverted helical beam of geometric phase +/-2 θ (x, y). By combining wave-plate elementsThe local orientation of the fast axis is controlled between 0 and pi and phase pick-up/retardation can be achieved over the
In accordance with an embodiment, and with reference to FIGS. 17A-17H, a
Still referring to fig. 17A-17H, the incident beam may be described by
See bottom row of FIG. 17A, incident | LCP>Electric field of light beam at initial time t ═ t0Pointing upward on the positive y-axis as shown by
FIGS. 17B-17H show | LCP's when the fast axis of the wave plate is rotated by an angle θ of π/4, π/2, 3 π/4, π,5 π/4, 3 π/2 and 7 π/4, respectively>How the polarization vector of the light beam changes. Independent of the angle of rotation, | RCP is generated>And outputting the light beam. However, referring to FIG. 17A, the resulting phase delays of
Thus, as an illustrative example, after passing through eight half-wave plate elements that are equally spaced and have a constant angular difference of orientation between adjacent (e.g., Δ θ ═ π/8), the transmitted RCP wave exhibits a constant phase difference between adjacent wave platesBy using eight wave plate elements with fast axis orientations varying between 0 and pi, phase retardation/pickup can be achieved covering the entire 0-2 pi range. However, half-wave plates with high diffraction angles for visible light are producedPieces can be challenging. This is because, among other things, the diffraction angle depends on the length of the period of the periodically repeating wave plate element, and due to space limitations, it may be difficult to form a relatively large number of half-wave plate elements within a relatively short length of the period.
In fig. 17A-17H, the half-wave plate shown includes, for illustrative purposes, eight equally spaced adjacent half-wave plate elements having a constant orientation angle difference Δ θ between adjacent wave plates, wherein each wave plate element includes a pattern of periodically repeating polymer-based optical structures having inorganic materials incorporated therein. However, embodiments are not limited thereto, and in the following, embodiments of phase-retarded/picked-up diffraction gratings covering the whole 0-2 π range with a smaller number of waveplates, with relatively high diffraction angles and diffraction efficiencies, and uniformity of diffraction efficiency across relatively wide angles of incidence, may be realized.
Applications of meta-surfaces including PBOE include diffraction gratings, such as blazed gratings, focusing lenses, and axicons, among various other applications. As described herein, a blazed grating is capable of steering a light beam into several diffraction orders. Blazed gratings may be configured to achieve high grating efficiency at one or more diffraction orders (e.g., +1 and/or-1 diffraction orders), resulting in optical power concentrated at the desired diffraction order, while the remaining power at other orders (e.g., zeroth) is low. In this disclosure, various embodiments of a meta-surface comprising a PBOE configured as a diffraction grating are described. According to various embodiments, the diffraction grating has a combination of desired optical properties, including one or more of a high diffraction angle, a high diffraction efficiency, a wide range of acceptance angles, and a highly uniform diffraction efficiency over a range of acceptance angles. These desired optical properties may result from a combination of various inventive aspects, including the material, dimensions, and geometric configuration of the super-surface elements.
As described herein, visible light may include light having one or more wavelengths in various color ranges including red, green, or blue color ranges. As described herein, red light may include light at one or more wavelengths in the range of about 620-780nm, green light may include light at one or more wavelengths in the range of about 492-577nm, and blue light may include light at one or more wavelengths in the range of about 435-493 nm. Thus, visible light may include light at one or more wavelengths in the range of about 435nm-780 nm.
As described herein, parallel, nominally parallel, or substantially parallel features, e.g., as nanobeams, lines, line segments, or unit cells, refer to features having directions of elongation that differ by less than about 10%, less than about 5%, or less than about 3%. Additionally, a perpendicular, nominally perpendicular, or substantially perpendicular feature refers to a feature having an extension direction that deviates from 90 degrees in the extension direction by less than about 10%, less than about 5%, or less than about 3%.
As described herein, a structure configured to diffract light, such as a diffraction grating, may diffract light in a transmissive mode and/or a reflective mode. As described herein, a structure configured to diffract light in a transmission mode refers to a structure in which the intensity of diffracted light on the other side of the structure opposite to the light incident side is greater than the intensity of diffracted light on the same side of the structure as the light incident side, for example, at least 10% greater, 20% greater, or 30% greater. In contrast, a structure configured to diffract light in the reflection mode refers to a structure in which the intensity of diffracted light on the same side of the structure as the light incident side is greater than the intensity of diffracted light on the opposite side of the structure as the light incident side, for example, at least 10% greater, 20% greater, or 30% greater.
As described herein, a wire, also referred to as a light beam or a nanobeam, is an elongated structure having a volume. As described above, the line or nano-beam is formed of a polymer material in which an inorganic material is incorporated. It will be understood that the wire is not limited to any particular cross-sectional shape. In some embodiments, the cross-sectional shape is rectangular.
Figures 18A and 18B illustrate cross-sectional side and top views, respectively, of a diffraction grating 1800 including a super-surface with geometric phase optical elements, according to some embodiments. The diffraction grating 1800 comprises a 2-order geometric phase metasurface. The cross-sectional side view shown with reference to fig. 18A is a side view of the cross-section AA' shown in fig. 18B. The diffraction grating 1800 includes a substrate 1804 having a surface on which is formed a metasurface 1808 configured to diffract light having a wavelength in the visible spectrum. The super-surface 1808 includes one or more first lines or nano-beams 1812 having a first orientation and extending generally in a first lateral direction (e.g., the y-direction) and a plurality of second lines or nano-beams 1816 having a second orientation and extending generally in a second direction (e.g., the x-direction). As described above, the one or more first wires or nano-strands 1812 and the plurality of second wires or nano-strands are formed of a polymer material having an inorganic material incorporated therein. The first wires or nanobeams 1812 may be considered to form a first set of nanobeams, while the second wires or nanobeams 1816 may be considered to form a second set of nanobeams. One or more first lines 1812 and second lines 1816 are disposed adjacent to each other in the second direction, and the first lines 1812 and second lines 1816 are alternately repeated in the second direction with a period less than a wavelength of light configured to be diffracted by the super surface.
Preferably, the first lines 1812 all have the same width. In some embodiments, second strands 1816 are stacked laterally in the y-direction between adjacent pairs of one or more first strands 1812. Without being limited by theory, the one or more first lines 1812 and second lines 1816 are oriented at an angle relative to each other to preferably induce a phase difference between visible light diffracted by the one or more first lines 1812 and visible light diffracted by the second lines 1816, wherein the phase difference between visible light diffracted by the one or more first lines 1812 and visible light diffracted by the second lines 1816 is twice the angle.
In some embodiments, similar to the combination of waveplates shown above with reference to fig. 17A-17H, the phase difference caused by the relative orientation of one or more first lines 1812 with respect to second lines 1816 may vary between 0 and pi, and the phase pick-up/retardation may be implemented to cover the entire 0-2 pi range. In some embodiments, a phase pickup/delay of 2 π between one or more first lines 1812 and second lines 1816 may be achieved when one of the one or more first lines 1812 and second lines 1816 are rotated π relative to each other, e.g., rotated π perpendicularly to each other. That is, unlike fig. 18A-18H, according to some embodiments, phase pick-up/delay covering the entire 0-2 pi range may be achieved based on a 2-level geometric phase super-surface with lines oriented in only two different directions. Advantageously, unlike the combinations of wave plates shown in fig. 17A-17H, i.e., with reference to fig. 17A-17H, the footprint occupied by the illustrated meta-surface 1808 is more compact and has a period less than or equal to a wavelength in the visible spectrum, which in turn enables relatively higher diffraction angles θ of the diffracted beams 1838, 1842.
The first line 1812 and the second line 1816 are formed of an optically transmissive material. As described herein and throughout the specification, a "transmissive" or "transparent" structure (e.g., a transmissive substrate) may allow at least some, e.g., at least 20, 30, 50, 70, or 90%, of incident light to pass through. Thus, in some embodiments, the transparent substrate may be a glass, sapphire, or polymer substrate. A "reflective" structure, such as a reflective substrate, can reflect at least some, e.g., at least 20%, 30%, 50%, 70%, 90%, or more, of the incident light therefrom.
The one or more first lines 1812 and second lines 1816 may be described as protrusions, ridge folds, or nano-wires that protrude out of the page, extend along the page, and have a width. Additionally or alternatively, the separation regions between adjacent first lines 1812 and/or between adjacent second lines 1816 can be described as depressions, slots, recesses, or grooves recessed into the page and having spaces. In some embodiments, the first line 1812 and the second line 1816 are elongated rectangular structures having a substantially rectangular cross-sectional shape in the yz plane. However, other embodiments are possible in which the first and second lines 1812, 1816 have a cross-sectional shape that may take the shape of a circle, an ellipse, a triangle, a parallelogram, a rhombus, a trapezoid, a pentagon, or any suitable shape.
In the following, various configurations including dimensions and geometric arrangements of one or more first lines 1812 and second lines 1816 are described, the combined effect of which is to produce a grating based on a geometrically phased optical element having desired optical characteristics described herein, including one or more of a relatively high diffraction angle, a relatively high diffraction efficiency, a relatively wide acceptance angle range, and a relatively uniform efficiency over the acceptance angle range.
Still referring to fig. 18A and 18B, in operation, when an incident light beam 1830, e.g., visible light, is incident on the super-surface 1808 at an incident angle α measured with respect to a plane (e.g., the yz plane) that is perpendicular to the surface 1804S and that extends in a direction parallel to the first line 1812, the grating 1800 partially transmits the incident light as a transmitted light beam 1834 and partially diffracts the incident light as a diffracted incident light at a diffracted angle θ1Diffracted beam 1842 of +1 order and at diffraction angle θ2Diffracted light beam 1838 of the-1 st order diffracted, where the diffraction angle is measured relative to the same plane (e.g., the yz plane) used to measure α when one or both of diffracted light beams 1838 and 1842 exceed the critical angle θTIRAre diffracted so that upon total internal reflection in substrate 1804 configured as a waveguide, diffracted light beams 1838 and 1842 propagate under Total Internal Reflection (TIR) along the x-axis in their respective opposite directions until the light beams reach OPE/EPE 1846, which may correspond to light distribution elements 730, 740, 750 and coupling-out optical elements 800, 810, 820 (fig. 9B).
Without being bound by any theory, when the first line 1812 and the second line 1816 with sub-wavelength feature sizes support leaky mode resonance, they may confine light, resulting in phase retardation in the scattered light waves generated under TE and TM illumination. It has been found that the effectiveness of confining light in one or more of first lines 1812 and second lines 1816 may be due to a waveguide configured to act as a resonator, and the resulting diffraction efficiency may depend on, among other factors, the material refractive indices and sub-wavelength dimensions of first lines 1812 and second lines 1816.
Accordingly, in some embodiments, first lines 1812 and/or second lines 1816 are formed of a material having a relatively high index of refraction. Thus, as described above, according to embodiments, after bonding the inorganic material, the first line 1812 and/or the second line 1816 have a second refractive index greater than 1.7, 1.8, 1.9, 2.0, or 2.1 and at least 0.2, 0.4, 0.6, 0.8, or 1.0 greater than the first refractive index.
With continued reference to fig. 18A and 18B, in addition to being formed from the various materials described above, the one or more first and second lines 1812 and 1816 have a particular combination of dimensions to function as a subwavelength sized resonator that induces phase shifts of light.
In various embodiments, W of first line 1812nano1And W of the second line 1816nano2Each of which is less than the wavelength of light that the meta-surface 1808 is configured to diffract, and preferably less than the wavelength in the visible spectrum. In some embodiments, Wnano1And Wnano2Each in the range of 10nm to 1 μm, 10nm to 500nm, 10nm to 300nm, 10nm to 100nm, or 10nm to 50nm, for example 30 nm. According to some embodiments, each of the one or more first lines 1812 has the same width Wnano1. According to some embodiments, each of the second lines 1816 has the same width Wnano2. According to some embodiments, one or more first lines 1812 and second lines 1816 have the same width, i.e., Wnano1=Wnano2. However, in other embodiments, Wnano1And Wnano2May be substantially different. Further, in some embodiments, different ones of the one or more first lines 1812 and/or different ones of the second lines 1816 may have different widths.
According to some embodiments, immediately adjacent ones of the one or more first lines 1812 in the second direction are at a constant spacing s1And (4) separating. In addition, one of the one or more first lines 1812 and one of the second lines 1816 next to each other in the second direction are at a constant interval s2And (4) separating. According to some embodiments, s1And s2Smaller than the wavelength at which the meta-surface 1808 is configured to diffract. In addition, the first line 1812 and the second line 1816 have a height h, respectivelynano1And hnano2. The interval s can be selected1、s2And a height hnano1And hnano2As described herein, the desired range Δ α may be described by a range of angles that spans negative and positive values of α, outside of which, with respect to α, a desired range of angles of incidence α (Δ α), sometimes referred to as a range of acceptance angles or field of view (FOV), is obtainedThe diffraction efficiency at 0, which decreases by more than 10%, 25%, or more than 50%, or more than 75%, for example, where uniform diffracted light intensity is desired within Δ α, it is desirable to have Δ α such that the diffraction efficiency is relatively flat within Δ α referring again to FIG. 18A, incident light beam 1830 is incident on the super surface 1808 and the surface of waveguide 1804 at an angle α relative to the surface normal (e.g., the yz plane). according to some embodiments, Δ α is associated with the angular bandwidth for super surface 1808, as described above, such that light beam 1830 within Δ α is effectively diffracted by super surface 1808 at a diffraction angle θ relative to the surface normal (e.g., the yz plane). The method of making waveguide devices according to the embodiments of the present invention can be used in conjunction with any number of optical waveguides, such as described belowTIROr over thetaTIRWhen diffracted light propagates within substrate 1804 under Total Internal Reflection (TIR).
It has been found that Δ α may depend on the shadowing effect created by adjacent lines in one or more first lines 1812 in the second direction and adjacent lines in second lines 1816 in the first direction1/hnano1、s2/hnano1And/or s2/hnano1Is associated with the arctangent of. In various embodiments, the ratio s1/hnano1、s2/hnano1And/or s2/hnano1Is selected such that Δ α exceeds 20 degrees (e.g., +/-10 degrees), 30 degrees (e.g., +/-15 degrees), 40 degrees (e.g., +/-20 degrees), or 50 degrees (e.g., +/-25 degrees), or is within an angular range defined by any of these values1/hnano1、s2/hnano1And/or s2/hnano1Wherein, for example, s1And s2Each in the range of 10nm to 1 μm, 10nm to 300nm, 10nm to 100nm, or 10nm to 50nm, for example 30 nm. Of course, can be represented by the formula (I) wherein hnano1And hnano2With a correspondingly relatively low value to implement s1And s2Relatively low value of (a).
Advantageously, according to one of some embodimentsOr a relatively high index of refraction (n) of the material of the plurality of first lines 1812 and/or second lines 18162) Allowing for a relatively small thickness or height. Thus, in various embodiments, the first line 1812 and the second line 1816 have hnano1And hnano2According to some embodiments, depending on n1It may be in the range of 10nm to 1 μm, 10nm to 500nm, 10nm to 300nm, 10nm to 100nm or 10nm to 50nm, for example 107 nm. E.g. hnano1And hnano2At n2In the case of more than 3.3, it may be from 10nm to 450nm, in n1And may be 10nm to 1 μm in the case of 3.3 or less. As another example, the height of the first line 1812 and the second line 1816 may be 10nm to 450 nm.
According to various embodiments, s may be selected1And Wnano1Such that the pitch (p) of the one or more first lines 1812nano1) Is defined as s1And Wnano1And having W selected from the range of from 10nm to 1 μm, 10nm to 500nm, 10nm to 300nm, 10nm to 100nm, or 10nm to 50nmnano1And s selected from the range of 10nm to 1 μm, 10nm to 300nm, 10nm to 100nm, or 10nm to 50nm1Of the sum of, e.g. pnano1=95.5nm。
Of course, s can be implemented1And s2And h is a relatively small value, andnano1and hnano2With a relatively small value. Advantageously, use is made of a material having a relatively high refractive index n1S may be obtained by forming one or more first lines 1812 and/or second lines 1816 from the material of (c)1、s2、hnano1And hnano2Relatively small value of. This is because, as found by the inventors, hnano1And hnano2May be inversely proportional to the bulk refractive index of the material forming first line 1812 and second line 1816. Thus, for polymer-based optical structures having refractive indices as described above, in various embodiments, hnano1And hnano2May be in the range of 500nm to 1 μm, 300nm to 500nm, 100nm to 300nm and 10nm to 100nm, respectively. Thus, having a high bulk refractive index n through one or more first lines 1812 and second lines 18161Of (d) and corresponding dimension s1、s2、hnano1And hnano2Total grid pitch ΛaAnd may be correspondingly reduced, which in turn increases the diffraction angle theta, as described further below.
Preferably, hnano1And hnano2Substantially equal, which may be advantageous for manufacturing. However, the embodiment is not limited thereto, and hnano1And hnano2May be substantially different.
In various embodiments, first line 1812 and/or second line 1816 are defined by their bulk refractive index (n)2Bulk) higher than the refractive index n of the substrate 18041Forming the material of (1); i.e. n2Body>n1. In some embodiments, substrate 1804 may be configured as a waveguide, and may correspond to
Still referring to fig. 18A and 18B, the super surface 1808 can be described as forming a plurality of super surface unit cells 1820 that repeat at least in the x-direction. As described herein, a super surface unit cell 1820 can be defined as a footprint with a minimum repeat dimension in the x-direction that includes one or more first lines 1812 and second lines 1816. As an example, each unit cell 1820 spans a unit cell width 1820a measured from the left perpendicular side of the left line of the first line 1812 in one unit cell 1820 to the left perpendicular side of the left line of the first line 1812 in the immediately adjacent unit cell 1820, and in the illustrated embodiment, thereby including pairs of first lines 1812 and columns of second lines 1816 stacked in the y-direction.
As described herein, the lateral dimension of a super-surface unit cell 1820 or the period of the repeating units of the unit cell 1820 may be referred to herein as a unit cell pitch ΛaGrid pitch ΛaWave-crossing in the x-directionThe guide 1804 is repeated at least twice at regular intervals, in other words, the unit cell pitch ΛaCan be the distance between the same points of directly adjacent unit cells 1820 in various embodiments, ΛaMay be less than the wavelength at which grating 1800 is configured to diffract, and may be less than the wavelength or any wavelength in the range of about 435nm-780nm in some embodiments configured to diffract at least red light, ΛaMay be less than a wavelength (or any wavelength) in the range of about 620-780nm in some other embodiments configured to diffract at least green light ΛaMay be less than a wavelength (or any wavelength) in the range of about 492-577nm in some other embodiments configured to diffract at least blue light, ΛaMay be less than a wavelength (or any wavelength) in the range of about 435-493nm optionally Λ according to various embodimentsaCan be in the range of 10nm to 1 μm, including 10nm to 500nm or 300nm to 500nm it is understood that each of the super surfaces disclosed herein can be used to diffract light and can be part of a display system 250 (FIG. 6), and that the display system 1000 can be configured to direct light to a super surface having a narrow band of wavelengthsaA light source smaller than the display system is configured to be directed at a minimum wavelength of a wavelength band of the super-surface.
It has been found that in some embodiments, ΛaMay have a ratio of less than m λ/(sin α + n)2sin θ), where m is an integer (e.g., 1,2, 3 …) and α, n2And theta have values described elsewhere in the specification, respectively, α may be in the range delta α of over 40 degrees, n2May be in the range of 1-2 and theta may be in the range of 40-80 degrees.
In some embodiments, ΛaMay be substantially constant across a surface 1804S of the grating 1800 formed by a plurality of unit cells, however, embodiments are not so limited, and in some other embodiments, ΛaMay vary across surface 1804S.
Still referring to fig. 18B, in some embodiments, each of the second lines 1816 is at least two, three, four, or more shorter in length than each of the one or more first lines 1812A factor of two or more. However, embodiments are possible in which the second line 1816 is longer than one or more of the first lines 1812. According to various embodiments, the one or more first wires 1812 may have a length L in the range of 200 μm-5mm, 200 μm-1mm, or 1mm-5mm1. According to various embodiments, the second line 1816 may have a length L in the range of 100nm to 500nm, 100nm to 300nm, and 300nm to 500nm2. In some embodiments, the one or more first lines 1812 may have a length L1The length L of1Corresponding to the overall lateral dimension of the optical element formed by the super-surface, e.g. corresponding to the length of the incoupling or outcoupling optical element formed by the super-surface comprising the wires 1812. In some embodiments, the second line has a length L2The length L of2Is unit cell pitch ΛaFrom about 40% to about 60%, e.g. ΛaAbout 50% of the total. In some embodiments, L1Such that one or more first lines 1812 span a distance in the y-direction corresponding to five second lines 1816. However, it should be understood that, according to various embodiments, one or more first lines 1812 may span a distance in the y-direction corresponding to any suitable number of second lines 1816 greater than 1, e.g., greater than 10, greater than 20, greater than 50, or greater than 100, or in a range between 10, 20, and 100.
Still referring to fig. 18A and 18B, in some embodiments, each of the second lines 1816 has the same length such that the second lines 1816 extend in the x-direction and collectively terminate without crossing any of the one or more first lines 1812. However, embodiments are possible in which the second lines 1816 have different lengths.
Still referring to the embodiment shown in fig. 18A, the extending direction (y-direction) of the one or more first lines 1812 is substantially perpendicular to the extending direction (x-direction) of the second lines 1816. That is, when the direction of propagation of incident light is observed (i.e., into the page), the second lines 1816 are rotated by a rotation angle of π/2 with respect to the one or more first lines 1812. However, embodiments are not limited thereto, and when observing the propagation direction of incident light (i.e., into the page), the second line 1816 may extend in any direction rotated in the counterclockwise direction by an angle less than π/2. For example, the second line 1816 may be rotated relative to the one or more first lines 1812 in a manner similar to the rotation of the nanobeam of the waveplate shown in fig. 17B-17H relative to the waveplate shown in fig. 17A. For example, the second lines 1816 may be rotated by a rotation angle θ of π/4, π/2, 3 π/4, π,5 π/4, 3 π/2 and 7 π/4 with respect to one or more first lines 1812. Therefore, when | LCP>The beam, when incident on a super-surface 1808 having first and second lines 1812 and 1816, produces | RCP>The output beam, in which the final phase retardation of the polarization vectors corresponding to the TE and TM polarizations may have
Where θ is the change in rotation angle when the fast axis of the wave plate is rotated by a rotation angle θ. In particular, for the embodiment shown, a second line 1816 rotated θ ═ pi/2 relative to one or more first lines 1812 diffracts an incident light beam, e.g., | LCP>Light beam, thereby generating diffracted RCP>Light beam, wherein diffracted light beam is delayed by second line 1816Thus, as shown in the illustrated embodiment, after passing through a hyper-surface 1808 in which one or more first lines 1812 and second lines 1816 alternate in the x-direction with a constant angular difference of orientation Δ θ ═ π/2, the transmitted RCP waves exhibit a constant phase difference between adjacent ones of the one or more first lines 1812 and second lines 1816As a result, by varying the fast axis orientation between 0 and pi, phase pick-up/retardation can be achieved covering the entire 0-2 pi range, but with a more compact unit cell pitch and larger diffraction angles than the examples shown in fig. 17A-17H.Having geometric phase-based metasurfaces formed from polymer-based optical structures incorporating inorganic materials Grating display device
As disclosed herein, in the various embodiments described above, the perimeter having inorganic materials incorporated therein can be configured as a super surfaceIt is contemplated that the linear polymer-based optical structure may be implemented as an incoupling optical element (e.g., as one or more of incoupling optical elements 700, 710, 720 (fig. 9A)) to incouple incident light such that light propagates through substrate 1304 via total internal reflection, however, it is recognized that the super-surface 1808 may also be configured to deflect light incident thereon from within substrate 1804, that in some embodiments, the super-surface disclosed herein may be applied to form an outcoupling optical element, such as one or more of outcoupling
Figure 19 illustrates a top view of a
Unlike the diffraction grating 1800 described above with reference to fig. 18A and 18B, the
Unlike the diffraction grating 1800 described above with reference to fig. 18A and 18B, the
In some embodiments, the third lines 2514 have the same length and/or the
In some embodiments, adjacent ones of the third lines 2514 are spaced apart by a constant spacing in a first direction (e.g., the y-direction) and/or adjacent ones of the
In some embodiments, the third lines 2514 have the same width and/or the
In some embodiments, when the direction of propagation of incident light is observed (e.g., into the page), the third lines 2514 extend in a third direction that is rotated counterclockwise relative to the one or more
In some embodiments, similar to the combination of wave plates shown above with reference to fig. 17A-17H, the phase difference caused by the relative orientation of one or more of the
Display device based on a geometrically phased super-surface comprising a polymer based bonded inorganic material Optical structure
In various embodiments of a display system (e.g., with reference to fig. 9A and 9B), a set of waveguides 1200 may include periodic polymer-based optical structures having inorganic materials incorporated therein, which may be configured as in a transmission modeIn various embodiments, waveguide set 1200 includes waveguides 670, 680, 690 corresponding to each component color (R, G, B), which in turn form therein or thereon a respective one of incoupling optical elements 700, 710, 720, which may include or correspond to
It will be appreciated that a substrate 1804 configured as a waveguide having a super-surface formed thereon according to various embodiments may be used to form a display system, such as the system 250 (fig. 6) disclosed herein. For example, a super-surface may be used as an incoupling, light distribution and/or outcoupling optical element as described herein. In some embodiments, after the super-surface is fabricated, the waveguide 2000 may be optically coupled to a light pipe, such as a light pipe for injecting image information from a spatial light modulator into the waveguide. In some embodiments, the light pipe may be an optical fiber. Examples of light pipes include
Other examples
1. A method of manufacturing an optical element, comprising:
providing a substrate having a first index of refraction and being transparent in the visible spectrum;
forming a periodically repeating polymer structure on the substrate; and
exposing the substrate to a metal precursor, and then to an oxidizing precursor,
wherein the exposing is performed under pressure and temperature such that an inorganic material comprising a metal of the metal precursor is incorporated into the periodically repeating polymer structure, thereby forming a pattern of periodically repeating optical structures configured to diffract visible light, the optical structures having a second refractive index that is greater than the first refractive index.
2. The method of example 1, wherein exposing is performed at a pressure between about 100mTorr and about 10 Torr.
3. The method of example 1 or example 2, wherein the exposing is performed at a temperature of less than about 150 degrees celsius.
4. The method of any of the preceding examples, wherein forming the periodically repeating polymer structure comprises patterning by nanoimprinting.
5. The method of any preceding example, wherein forming the periodically repeating polymer structure comprises lithographic patterning.
6. The method of any of the preceding examples, wherein the periodically repeating polymer structures are formed from a material having a bulk refractive index that is less than the second refractive index, and the inorganic material has a bulk refractive index that is greater than the second refractive index.
7. The method of any of the preceding examples, wherein the second refractive index is greater than 1.7 and at least 0.2 greater than the first refractive index.
8. The method of any preceding example, wherein the substrate has a refractive index greater than 1.5.
9. The method of any of the preceding examples, wherein the periodically repeating polymer structure comprises a photoresist.
10. The method of any of the preceding examples, wherein exposing the substrate to the metal precursor comprises: exposure to a precursor comprising a transition metal selected from the group consisting of aluminum, zinc, zirconium, hafnium, and titanium.
11. The method of any of the preceding examples, wherein exposing the substrate to the metal precursor and the oxidizing precursor comprises: the exposure is conducted at a partial pressure of the respective precursor and for a duration sufficient to saturate the exposed surface of the periodically repeating polymeric structure with at least a monolayer of the inorganic material.
12. The method of any of the preceding examples, wherein exposing the substrate to one or both of the metal precursor and the oxidizing precursor comprises: the exposure was for a duration of more than 1 second.
13. The method of any of the preceding examples, wherein the inorganic material incorporated into the periodically repeating polymer structure comprises a metal oxide.
14. The method of example 13, wherein the metal oxide comprises a transition metal oxide.
15. The method of example 14, wherein the metal oxide comprises an oxide selected from the group consisting of: aluminum oxide, zinc oxide, zirconium oxide, hafnium oxide, and titanium oxide.
16. The method of any one of the preceding examples, wherein the exposing binds the inorganic material selectively through an exposed surface of the periodically repeating polymer structure relative to an exposed surface of the substrate.
17. The method of example 16, wherein forming the periodically repeating polymer structure comprises being separated by a space having a substrate surface on which no polymer layer is disposed, wherein exposing does not result in deposition of the inorganic material on the substrate surface in the space or bonding of the inorganic material through the substrate surface in the space.
18. The method of example 16, wherein forming the periodically repeating polymer structures comprises being separated by spaces having a substrate surface with a polymer layer disposed thereon, the polymer layer having a thickness less than a height of the periodically repeating polymer structures, wherein exposing incorporates the inorganic material into the polymer layer formed on the substrate surface in the spaces.
19. The method of example 18, wherein an entire thickness of the polymer layer formed on the substrate surface in the space is bonded with the inorganic material.
20. The method of example 18, wherein the polymer layer formed on the substrate surface in the space has a partial thickness bonded to the inorganic material and a partial thickness unbonded to the inorganic material.
21. An optical element, comprising:
a substrate having a first index of refraction and being transparent in the visible spectrum; and
a pattern of periodically repeating optical structures formed on the substrate and configured to diffract visible light, the optical structures having a second refractive index greater than the first refractive index and comprising a polymer material having an inorganic material incorporated therein.
22. The optical element of example 21, wherein the polymer material has a bulk refractive index less than the second refractive index and the inorganic material has a bulk refractive index higher than the second refractive index.
23. The optical element of example 21 or example 22, wherein the second refractive index is greater than 1.7 and at least 0.2 greater than the first refractive index.
24. An optical element according to any one of examples 21 to 23, wherein the substrate has a refractive index greater than 1.5.
25. An optical element according to any one of examples 21-24, wherein the polymeric material comprises a photoresist.
26. An optical element according to any one of examples 21-25, wherein the inorganic material comprises a transition metal oxide.
27. The optical element of example 26, wherein the inorganic material comprises a metal oxide.
28. The optical element of example 27, wherein the metal oxide comprises an oxide selected from the group consisting of: aluminum oxide, zinc oxide, zirconium oxide, hafnium oxide, and titanium oxide.
29. An optical element according to example 27, wherein the inorganic material is incorporated into a surface region of the optical structure and a core region of the optical structure has no inorganic material incorporated therein.
30. An optical element according to any one of examples 21-29, wherein adjacent ones of the periodically repeating optical structures are separated by a space, wherein a surface of the substrate in the space is free of the inorganic material disposed thereon.
31. An optical element according to any one of examples 21 to 30, adjacent ones of the periodically repeating optical structures being spaced apart, wherein a surface of the substrate in the spaces has formed thereon a layer of polymeric material having the inorganic material incorporated therein, the layer having a thickness less than a height of the optical structures.
32. The optical element of example 31, wherein an entire thickness of the layer of polymeric material formed in the space is bonded to the inorganic material.
33. The optical element of example 31, wherein the layer of polymer material formed in the space has a partial thickness bonded to the inorganic material at a surface region and a partial thickness not bonded to the inorganic material.
34. The optical element of any of examples 21-33, wherein the substrate is configured such that visible light diffracted by the periodically repeating optical structure propagates under total internal reflection.
35. An optical system, comprising:
an optical element comprising:
a substrate having a first refractive index and being transparent in the visible spectrum, an
A pattern of periodically repeating optical structures formed on the substrate and configured to diffract visible light, the optical structures having a second refractive index greater than the first refractive index and comprising a polymer material having an inorganic material incorporated therein,
wherein the periodically repeating optical structure comprises a nanobeam arranged as a super-surface comprising a plurality of repeating unit cells, each unit cell comprising:
a first set of nanobeams formed by one or more first nanobeams; and
a second set of nanobeams formed by one or more second nanobeams disposed adjacent to the one or more first nanobeams and spaced apart from each other at sub-wavelength intervals,
wherein the one or more first nanobeams and the plurality of second nanobeams are elongated in different orientation directions.
36. The optical system of example 35, wherein the unit cell repeats with a period less than or equal to about 10nm to 1 μ ι η.
37. The optical system of example 35 or example 36, wherein the one or more first and second nanobeams are oriented at an angle relative to each other to induce a phase difference between the visible light diffracted by the one or more first nanobeams and the visible light diffracted by the second nanobeams.
38. The optical system of any of examples 35-37, wherein the one or more first and second nanobeams are oriented in an orientation direction that is rotated about 90 degrees relative to each other.
39. The optical system of any of examples 35-38, wherein the unit cell repeats with a period less than or equal to the wavelength, wherein the wavelength is within the visible spectrum.
40. The optical system of any of examples 35-39, wherein the one or more first and second nanobeams have a height less than the wavelength.
41. An optical system comprising a waveguide configured to propagate visible light, the optical system comprising:
a substrate having a first index of refraction and being transparent in the visible spectrum to enable light to be guided therein by total internal reflection; and
a pattern of periodically repeating optical structures formed on the substrate and configured to diffract visible light, the optical structures having a second refractive index greater than the first refractive index and comprising a polymer material having an inorganic material incorporated therein,
wherein the periodically repeating optical structure is arranged to diffract light at a diffraction angle relative to the direction of incident light and to cause the diffracted light to propagate under total internal reflection in the substrate, or to diffract light guided under total internal reflection within the substrate at a diffraction angle relative to the direction of light guided within the substrate.
42. The optical system of example 41, wherein the polymer material has a bulk refractive index that is less than the second refractive index and the inorganic material has a bulk refractive index that is higher than the second refractive index.
43. The optical system of example 41 or example 42, wherein the second refractive index is greater than 1.7 and at least 0.2 greater than the first refractive index.
44. The optical system of any of examples 41-43, wherein the diffraction angle exceeds 50 degrees.
45. The optical system of any of examples 41-44, further comprising a light source configured to emit light of the wavelength to the pattern of periodically repeating optical structures.
46. The optical system of any of examples 41 to 45, further comprising a spatial light modulator configured to modulate light from the light source and output the modulated light to the pattern of periodically repeating optical structures.
47. A head-mounted display device configured to project light to an eye of a user to display augmented reality image content, the head-mounted display device comprising:
a frame configured to be supported on a head of a user;
a display disposed on the frame, at least a portion of the display comprising:
one or more waveguides that are transparent and are disposed at a location in front of the user's eyes when the user wears the head mounted display device such that the transparent portion transmits light from a portion of the environment in front of the user to the user's eyes to provide a view of the portion of the environment in front of the user;
one or more light sources; and
at least one diffraction grating configured to couple light from the light source into or out of the one or more waveguides, the diffraction grating comprising an optical element comprising:
a substrate having a first index of refraction and being transparent in the visible spectrum; and
a pattern of periodically repeating optical structures formed on a substrate and configured to diffract visible light, the optical structures having a second refractive index greater than the first refractive index and comprising a polymer material having an inorganic material incorporated therein.
48. The apparatus of example 47, wherein the one or more light sources comprise a fiber scanning projector.
49. The apparatus of example 47 or example 48, wherein the display is configured to project light into an eye of a user to present image content to the user on a plurality of depth planes.
50. The method of any of examples 1-20, wherein exposing is performed at a pressure of less than 10atm (atmospheric pressure).
51. The method of any of examples 1-20 and 50, wherein exposing is performed at a temperature greater than 25 degrees Celsius.
52. The method of any of examples 1-20 and 50-51, wherein exposing the substrate to one or both of the metal precursor and the oxidizing precursor comprises: the exposure is for a duration of about 1 second to about 1000 seconds.
53. The method of any of examples 1-20 and 50-52, wherein the inorganic material incorporated into the periodically repeating polymer structure comprises a metal nitride.
54. The optical element of any of examples 21-34, wherein the periodically repeating optical structure comprises a super-surface.
55. The optical element of any of examples 21-34 and 54, wherein the substrate is configured such that visible light is guided therein under total internal reflection and diffracted out of the substrate by the periodically repeating optical structure.
56. The optical element of any of examples 21-34 and 54-55, wherein the substrate is configured such that visible light is guided therein under total internal reflection and diffracted by the periodically repeating optical structure so as to alter a direction in which the light beam propagates within the substrate by total internal reflection.
57. The optical system of any of examples 41-46, wherein the periodically repeating optical structures are arranged to diffract light at a diffraction angle relative to a direction of incident light and to cause the diffracted light to propagate under total internal reflection in the substrate.
58. The optical system of any of examples 41-46 and 57, wherein the periodically repeating optical structures are arranged to diffract light guided under total internal reflection within the substrate at an angle of diffraction relative to a direction of the light guided within the substrate.
59. The optical system of example 58, wherein the periodically repeating optical structures are arranged to diffract light guided under total internal reflection within the substrate out of the substrate.
60. A method of manufacturing an optical element, comprising:
providing a substrate transparent in the visible spectrum;
forming a periodically repeating polymer structure having a first refractive index on the substrate; and
exposing the substrate to a metal precursor, and then to an oxidizing precursor,
wherein the exposing is performed under pressure and temperature such that an inorganic material comprising a metal of the metal precursor is incorporated into the periodically repeating polymer structure, thereby increasing the refractive index of the periodically repeating polymer structure to form a pattern of periodically repeating optical structures configured to diffract visible light.
61. The method of example 60, wherein exposing is performed at a pressure between about 100mTorr and about 10 Torr.
62. The method of example 60 or example 61, wherein the exposing is performed at a temperature of less than about 150 degrees celsius.
63. The method of any of examples 60-62, wherein forming the periodically repeating polymer structure comprises patterning by nanoimprinting.
64. The method of any of examples 60-63, wherein forming the periodically repeating polymer structure comprises lithographic patterning.
65. The method of any of examples 60-64, wherein the periodically repeating polymeric structures are formed from a material having a bulk refractive index that is less than a refractive index of the periodically repeating optical structures, and the inorganic material has a bulk refractive index that is greater than the refractive index of the periodically repeating optical structures.
66. The method of any of examples 60-65, wherein the periodically repeating optical structures have a refractive index greater than 1.7 and at least 0.2 greater than the refractive index of the periodically repeating polymer structures.
67. The method of any of examples 60-66, wherein the substrate has a refractive index greater than 1.5.
68. The method of any of examples 60-67, wherein the periodically repeating polymer structure comprises a photoresist.
69. The method of any of examples 60-68, wherein exposing the substrate to the metal precursor comprises: exposure to a precursor comprising a transition metal selected from the group consisting of aluminum, zinc, zirconium, hafnium, and titanium.
70. The method of any of examples 60-69, wherein exposing the substrate to the metal precursor and the oxidizing precursor comprises: the exposure is conducted at a partial pressure of the respective precursor and for a duration sufficient to saturate the exposed surface of the periodically repeating polymeric structure with at least a monolayer of the inorganic material.
71. The method of any of examples 60-70, wherein exposing the substrate to one or both of the metal precursor and the oxidizing precursor comprises: the exposure was for a duration of more than 1 second.
72. The method of any of examples 60-71, wherein the inorganic material incorporated into the periodically repeating polymer structure comprises a metal oxide.
73. The method of example 72, wherein the metal oxide comprises a transition metal oxide.
74. The method of example 73, wherein the metal oxide comprises an oxide selected from the group consisting of: aluminum oxide, zinc oxide, zirconium oxide, hafnium oxide, and titanium oxide.
75. The method of any of examples 60-74, wherein the exposing binds the inorganic material selectively through an exposed surface of the periodically repeating polymer structure relative to an exposed surface of the substrate.
76. The method of example 75, wherein forming the periodically repeating polymer structure comprises being separated by a space having a substrate surface on which no polymer layer is disposed, wherein exposing does not result in deposition of the inorganic material on the substrate surface in the space or bonding of the inorganic material through the substrate surface in the space.
77. The method of example 75, wherein forming the periodically repeating polymer structures comprises being separated by a space having a substrate surface with a polymer layer disposed thereon, the polymer layer having a thickness less than a height of the periodically repeating polymer structures, wherein exposing incorporates the inorganic material into the polymer layer formed on the substrate surface in the space.
78. The method of example 77, wherein an entire thickness of the polymer layer formed on the substrate surface in the space is bonded with the inorganic material.
79. The method of example 77, wherein the polymer layer formed on the substrate surface in the space has a partial thickness bonded to the inorganic material and a partial thickness unbonded to the inorganic material.
80. A method of manufacturing an optical element, comprising:
providing a substrate having a first refractive index and being transparent in the visible spectrum, wherein the substrate has formed thereon a periodically repeating polymer structure; and
exposing the substrate to a metal precursor, and then to an oxidizing precursor,
wherein the exposing is performed under pressure and temperature such that an inorganic material comprising a metal of the metal precursor is incorporated into the periodically repeating polymer structure, thereby forming a pattern of periodically repeating optical structures configured to diffract visible light, the optical structures having a second refractive index that is greater than the first refractive index.
81. The method of example 80, wherein exposing is performed at a pressure between about 100mTorr and about 10 Torr.
82. The method of example 80 or example 81, wherein the exposing is performed at a temperature of less than about 150 degrees celsius.
83. The method of any of examples 80-82, wherein forming the periodically repeating polymer structure comprises patterning by nanoimprinting.
84. The method of any of examples 80-83, wherein forming the periodically repeating polymer structure comprises lithographic patterning.
85. The method of any of examples 80-84, wherein the periodically repeating polymer structures are formed from a material having a bulk refractive index that is less than the second refractive index, and the inorganic material has a bulk refractive index that is greater than the second refractive index.
86. The method of any of examples 80-85, wherein the second refractive index is greater than 1.7 and at least 0.2 greater than the first refractive index.
87. The method of any of examples 80-86, wherein the substrate has a refractive index greater than 1.5.
88. The method of any of examples 80-87, wherein the periodically repeating polymer structure comprises a photoresist.
89. The method of any of examples 80-88, wherein exposing the substrate to the metal precursor comprises: exposure to a precursor comprising a transition metal selected from the group consisting of aluminum, zinc, zirconium, hafnium, and titanium.
90. The method of any of examples 80-89, wherein exposing the substrate to the metal precursor and the oxidizing precursor comprises: the exposure is conducted at a partial pressure of the respective precursor and for a duration sufficient to saturate the exposed surface of the periodically repeating polymeric structure with at least a monolayer of the inorganic material.
91. The method of any of examples 80-90, wherein exposing the substrate to one or both of the metal precursor and the oxidizing precursor comprises: the exposure was for a duration of more than 1 second.
92. The method of any of examples 80-91, wherein the inorganic material incorporated into the periodically repeating polymer structure comprises a metal oxide.
93. The method of example 92, wherein the metal oxide comprises a transition metal oxide.
94. The method of example 93, wherein the metal oxide comprises an oxide selected from the group comprising: aluminum oxide, zinc oxide, zirconium oxide, hafnium oxide, and titanium oxide.
95. The method of any of examples 80-94, wherein the exposing binds the inorganic material selectively through an exposed surface of the periodically repeating polymer structure relative to an exposed surface of the substrate.
96. The method of example 95, wherein forming the periodically repeating polymer structures comprises being separated by a space having a substrate surface on which no polymer layer is disposed, wherein exposing does not result in deposition of the inorganic material on the substrate surface in the space or bonding of the inorganic material through the substrate surface in the space.
97. The method of example 96, wherein forming the periodically repeating polymer structures comprises being separated by a space having a substrate surface with a polymer layer disposed thereon, the polymer layer having a thickness less than a height of the periodically repeating polymer structures, wherein exposing incorporates the inorganic material into the polymer layer formed on the substrate surface in the space.
98. The method of example 97, wherein an entire thickness of the polymer layer formed on the substrate surface in the space is bonded with the inorganic material.
99. The method of example 97, wherein the polymer layer formed on the substrate surface in the space has a partial thickness bonded to the inorganic material and a partial thickness unbonded to the inorganic material.
100. The method of any of examples 80-99, wherein exposing is performed at a pressure less than 10atm (atmospheric pressure).
101. The method of any of examples 80-100, wherein exposing is performed at a temperature greater than 25 degrees celsius.
102. The method of any of examples 80-101, wherein exposing the substrate to one or both of the metal precursor and the oxidizing precursor comprises: the exposure is for a duration of about 1 second to about 1000 seconds.
103. The method of any of examples 80-102, wherein the inorganic material incorporated into the periodically repeating polymer structure comprises a metal nitride.
104. The method of example 1, wherein exposing is performed at a pressure between about 100mTorr and about 10 Torr.
105. The method of example 2, wherein exposing is performed at a temperature of less than about 150 degrees celsius.
106. The method of example 1, wherein forming the periodically repeating polymer structure comprises patterning by nanoimprinting.
107. The method of example 1, wherein forming the periodically repeating polymer structure comprises lithographic patterning.
108. The method of example 1, wherein the periodically repeating polymer structures are formed of a material having a bulk refractive index that is less than the second refractive index, and the inorganic material has a bulk refractive index that is greater than the second refractive index.
109. The method of example 1, wherein the second refractive index is greater than 1.7 and at least 0.2 greater than the first refractive index.
110. The method of example 1, wherein the substrate has a refractive index greater than 1.5.
111. The method of example 1, wherein the periodically repeating polymer structure comprises a photoresist.
112. The method of example 1, wherein exposing the substrate to the metal precursor comprises: exposure to a precursor comprising a transition metal selected from the group consisting of aluminum, zinc, zirconium, hafnium, and titanium.
113. The method of example 1, wherein exposing the substrate to the metal precursor and the oxidizing precursor comprises: the exposure is conducted at a partial pressure of the respective precursor and for a duration sufficient to saturate the exposed surface of the periodically repeating polymeric structure with at least a monolayer of the inorganic material.
114. The method of example 1, wherein exposing the substrate to one or both of the metal precursor and the oxidizing precursor comprises: the exposure was for a duration of more than 1 second.
115. The method of example 1, wherein the inorganic material incorporated into the periodically repeating polymer structure comprises a metal oxide.
116. The method of example 13, wherein the metal oxide comprises a transition metal oxide.
117. The method of example 14, wherein the metal oxide comprises an oxide selected from the group consisting of: aluminum oxide, zinc oxide, zirconium oxide, hafnium oxide, and titanium oxide.
118. The method of example 1, wherein the exposing is selectively bonded to the inorganic material through the exposed surface of the periodically repeating polymer structure relative to the exposed surface of the substrate.
119. The method of example 16, wherein forming the periodically repeating polymer structure comprises being separated by a space having a substrate surface on which no polymer layer is disposed, wherein exposing does not result in deposition of the inorganic material on the substrate surface in the space or bonding of the inorganic material through the substrate surface in the space.
120. The method of example 16, wherein forming the periodically repeating polymer structures comprises being separated by spaces having a substrate surface with a polymer layer disposed thereon, the polymer layer having a thickness less than a height of the periodically repeating polymer structures, wherein exposing incorporates the inorganic material into the polymer layer formed on the substrate surface in the spaces.
121. The method of example 18, wherein an entire thickness of the polymer layer formed on the substrate surface in the space is bonded with the inorganic material.
122. The method of example 18, wherein the polymer layer formed on the substrate surface in the space has a partial thickness bonded to the inorganic material and a partial thickness unbonded to the inorganic material.
123. The method of example 80, wherein exposing is performed at a pressure between about 100mTorr and about 10 Torr.
124. The method of example 80, wherein exposing is performed at a temperature of less than about 150 degrees celsius.
125. The method of example 80, wherein forming the periodically repeating polymer structures comprises patterning by nanoimprinting.
126. The method of example 80, wherein forming the periodically repeating polymer structure comprises lithographic patterning.
127. The method of example 80, wherein the periodically repeating polymeric structures are formed from a material having a bulk refractive index that is less than a refractive index of the periodically repeating optical structures, and the inorganic material has a bulk refractive index that is greater than the refractive index of the periodically repeating optical structures.
128. The method of example 80, wherein the periodically repeating optical structures have a refractive index greater than 1.7 and at least 0.2 greater than the refractive index of the periodically repeating polymer structures.
129. The method of example 80, wherein the substrate has a refractive index greater than 1.5.
130. The method of example 80, wherein the periodically repeating polymer structure comprises a photoresist.
131. The method of example 80, wherein exposing the substrate to the metal precursor comprises: exposure to a precursor comprising a transition metal selected from the group consisting of aluminum, zinc, zirconium, hafnium, and titanium.
132. The method of example 80, wherein exposing the substrate to the metal precursor and the oxidizing precursor comprises: the exposure is conducted at a partial pressure of the respective precursor and for a duration sufficient to saturate the exposed surface of the periodically repeating polymeric structure with at least a monolayer of the inorganic material.
133. The method of example 80, wherein exposing the substrate to one or both of the metal precursor and the oxidizing precursor comprises: the exposure was for a duration of more than 1 second.
134. The method of example 80, wherein the inorganic material incorporated into the periodically repeating polymer structure comprises a metal oxide.
135. The method of example 134, wherein the metal oxide comprises a transition metal oxide.
136. The method of example 135, wherein the metal oxide comprises an oxide selected from the group comprising: aluminum oxide, zinc oxide, zirconium oxide, hafnium oxide, and titanium oxide.
137. The method of example 80, wherein exposing is selectively bonded to the inorganic material through the exposed surface of the periodically repeating polymer structure relative to the exposed surface of the substrate.
138. The method of example 137, wherein forming the periodically repeating polymer structure comprises being separated by a space having a substrate surface on which no polymer layer is disposed, wherein exposing does not result in deposition of the inorganic material on the substrate surface in the space or bonding of the inorganic material through the substrate surface in the space.
139. The method of example 137, wherein forming the periodically repeating polymer structures comprises being separated by a space having a substrate surface with a polymer layer disposed thereon, the polymer layer having a thickness less than a height of the periodically repeating polymer structures, wherein exposing incorporates the inorganic material into the polymer layer formed on the substrate surface in the space.
140. The method of example 139, wherein an entire thickness of the polymer layer formed on the substrate surface in the space is bonded with the inorganic material.
141. The method of example 139, wherein the polymer layer formed on the substrate surface in the space has a partial thickness bonded to the inorganic material and a partial thickness unbonded to the inorganic material.
142. The method of manufacturing an optical element of any of examples 1-20 and 50-53, wherein the method further comprises integrating the optical element as part of head mounted augmented reality glasses.
143. The method of manufacturing an optical element according to any one of examples 60-79, wherein the method further comprises integrating the optical element as part of head mounted augmented reality glasses.
144. The method of manufacturing an optical element of any of examples 80-103, wherein the method further comprises integrating the optical element as part of head mounted augmented reality glasses.
145. A head-mounted display device configured to project light to an eye of a user to display augmented reality image content, the head-mounted display device comprising:
a frame configured to be supported on a head of a user;
a display disposed on the frame, at least a portion of the display comprising:
one or more waveguides that are transparent and are disposed at a location in front of the user's eyes when the user wears the head mounted display device such that the transparent portion transmits light from a portion of the environment in front of the user to the user's eyes to provide a view of the portion of the environment in front of the user;
one or more light sources; and
the optical element of any of examples 21-34 and 54-56, wherein the one or more waveguides of the display comprise the substrate of the optical element, and wherein the optical element is configured to couple light from the one or more light sources into or out of the one or more waveguides.
146. A head-mounted display device configured to project light to an eye of a user to display augmented reality image content, the head-mounted display device comprising:
a frame configured to be supported on a head of a user;
a display disposed on the frame and having a display screen,
one or more light sources; and
the optical element of any of examples 21-34 and 54-56, wherein the optical element is configured to direct light originating from the one or more light sources into the eye of the user.
147. A head-mounted display device configured to project light to an eye of a user to display augmented reality image content, the head-mounted display device comprising:
a frame configured to be supported on a head of a user;
a display disposed on the frame and having a display screen,
one or more light sources; and
the optical element of any one of examples 35-40, wherein the optical element is configured to direct light originating from the one or more light sources into the eye of the user.
148. A head-mounted display device configured to project light to an eye of a user to display augmented reality image content, the head-mounted display device comprising:
a frame configured to be supported on a head of a user;
a display disposed on the frame and having a display screen,
one or more light sources; and
the optical element of any one of examples 41-46 and 57-59, wherein the optical element is configured to direct light originating from the one or more light sources into the eye of the user.
Various illustrative examples of the present invention are described herein. Reference is made to these examples in a non-limiting sense. These examples are provided to illustrate the broader application aspects of the present invention. Various changes may be made and equivalents may be substituted for elements thereof without departing from the true spirit and scope of the invention.
For example, while advantageously used with an AR display that provides images on multiple depth planes, the augmented reality content disclosed herein may also be displayed by a system that provides images on a single depth plane and/or with a virtual reality display. In some embodiments where multiplexed image information (e.g., different colors of light) is directed into the waveguide, multiple optical elements or super-surfaces may be provided on the waveguide, e.g., one optical element or super-surface active for each color of light. In some embodiments, the pitch or period and/or geometry of the protrusions forming the optical element or the super-surface may vary across its surface. Such an optical element or super-surface may function in redirecting light of different wavelengths, depending on the geometry and pitch at the location where the light is incident on the optical element or super-surface. In some other embodiments, the geometry and pitch of the optical element or the super-surface features are configured to vary such that even deflected rays with similar wavelengths propagate away from the optical element or the super-surface at different angles. It is also understood that a plurality of separate optical elements or super-surfaces may be disposed across the entire substrate surface, in some embodiments each of the optical elements or super-surfaces having the same geometry and pitch, or in some other embodiments at least some of the optical elements or super-surfaces having a different geometry and pitch than the other optical elements or super-surfaces.
Moreover, although advantageously applied to displays such as wearable displays, the optical element or super-surface may be applied to various other devices that require a compact, low-profile light redirecting element. For example, optical elements or super surfaces may be commonly applied to form light redirecting components of optical plates (e.g., glass plates), optical fibers, microscopes, sensors, watches, cameras, and image projection devices.
In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process action or steps, to the objective(s), spirit or scope of the present invention. Furthermore, as will be understood by those of skill in the art, each of the various modifications described and illustrated herein has discrete components and features which may be readily separated from or combined with any of the features of the other several embodiments without departing from the scope or spirit of the present invention. All such modifications are intended to be within the scope of the claims associated with this disclosure.
The invention includes methods that may be performed using the subject devices. The method may include the act of providing such a suitable device. Such provision may be performed by a user. In other words, the act of "providing" merely requires the user to obtain, access, approach, locate, set, activate, turn on, or otherwise provide the necessary means in the method. The methods described herein may be performed in any order of the described events that is logically possible, as well as in the order of the events that are described.
Exemplary aspects of the invention and details regarding material selection and fabrication have been set forth above. Additional details regarding the present invention can be found in conjunction with the above-referenced patents and publications and as generally known or understood by those skilled in the art. The same may hold true with respect to additional actions that are commonly or logically utilized with respect to aspects of the underlying method according to the invention.
For ease of description, various terms indicating relative positions of features are used herein. For example, various features may be described as being "on," "over," "to one side" of "upper" or "lower" other features. Other words of relative position may also be used. All such relative positional terms assume that the polymeric structure or system with the features integrally formed therewith is in a certain orientation as a point of reference for purposes of description, but it is to be understood that the structure may be positioned laterally, inverted or in any other orientation when in use.
In addition, while the invention has been described with reference to several examples that optionally incorporate various features, the invention is not limited to the described or indicated invention as contemplated for each variation of the invention. Various changes may be made to the invention described and equivalents may be substituted (whether included or not for the sake of brevity) without departing from the true spirit and scope of the invention. Further, where a range of values is provided, it is understood that each intervening value, to the extent that there is no such stated or intervening value, to the upper and lower limit of that range, and any other stated or intervening value in that stated range, is encompassed within the invention.
Additionally, it is contemplated that any optional feature of the described variations of the invention may be set forth and claimed independently or in combination with any one or more of the features described herein. Reference to a singular item includes a plural of the same item that may be present. More specifically, as used herein and in the appended claims, the singular forms "a," "an," "said," and "the" include plural referents unless the context clearly dictates otherwise. In other words, the use of the article "at least one" target item is permitted in the foregoing description as well as in the claims associated with this disclosure. It is further noted that such claims may be drafted to exclude any optional element. Thus, the statement herein is intended to serve as antecedent basis for use of such exclusive terminology as "solely," "only," and the like in connection with the claim element or use of a "negative" limitation.
The term "comprising" in the claims associated with this disclosure should be allowed to include any additional elements without using such exclusive terminology, regardless of whether a given number of elements or added features are recited in such claims, may be considered to change the nature of the elements recited in the claims. Except as specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood meaning as possible while maintaining claim validity.
The breadth of the present invention is not limited by the examples and/or subject specification provided, but is only limited by the scope of the claim language associated with this disclosure. Indeed, the novel apparatus, methods, and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the disclosure. For example, while blocks are presented in a given arrangement, alternative embodiments may perform similar functions in different components and/or circuit topologies, and some blocks may be deleted, moved, added, subdivided, combined, and/or modified. Each of these blocks may be implemented in a variety of different ways. Any suitable combination of the elements and acts of the various embodiments described above can be combined to provide further embodiments. The various features and processes described above may be implemented independently of one another or may be combined in various ways. All suitable combinations and subcombinations of the features of the disclosure are intended to be within the scope of the disclosure.
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