阅读说明：本技术 波导衍射装置和显示眼镜 (Waveguide diffraction device and display glasses ) 是由 蒋厚强 邓家裕 朱以胜 于 2021-09-14 设计创作，主要内容包括：本申请涉及一种波导衍射装置和显示眼镜,波导衍射装置包括：衍射波导,包括入瞳区、第一扩瞳区、第二扩瞳区和出瞳区,第一扩瞳区位于入瞳区的水平侧,第二扩瞳区位于入瞳区的下侧,出瞳区位于第一扩瞳区和第二扩瞳区的光路重叠处；入瞳区设置有两个入瞳光栅,第一扩瞳区和第二扩瞳区均设置有扩瞳光栅,出瞳区设置有两个出瞳光栅；投影光机,用于发出波长不同的第一入射光和第二入射光,第一入射光入射第一入瞳光栅,经第一扩瞳光栅衍射,由第一出瞳光栅射出；第二入射光入射第二入瞳光栅,经第二扩瞳光栅衍射,由第二出瞳光栅射出；由两个出瞳光栅射出的两个出瞳光在出瞳区合束形成彩色图像。本申请单片波导即可实现彩色显示,且能够保证色彩的均匀性和出光亮度。(The present application relates to a waveguide diffraction device and display glasses, the waveguide diffraction device including: the diffraction waveguide comprises an entrance pupil area, a first expanded pupil area, a second expanded pupil area and an exit pupil area, wherein the first expanded pupil area is positioned on the horizontal side of the entrance pupil area, the second expanded pupil area is positioned on the lower side of the entrance pupil area, and the exit pupil area is positioned at the position where the light paths of the first expanded pupil area and the second expanded pupil area are overlapped; the entrance pupil area is provided with two entrance pupil gratings, the first and second pupil areas are provided with pupil gratings, and the exit pupil area is provided with two exit pupil gratings; the projection optical machine is used for emitting first incident light and second incident light with different wavelengths, the first incident light enters the first entrance pupil grating, is diffracted by the first pupil grating, and is emitted by the first exit pupil grating; the second incident light enters the second entrance pupil grating, is diffracted by the second pupil grating and is emitted by the second exit pupil grating; the two exit pupil lights emitted by the two exit pupil gratings are combined in the exit pupil area to form a color image. The single-chip waveguide can realize color display, and can ensure color uniformity and light-emitting brightness.)

1. A waveguide diffraction device, comprising:

the diffraction waveguide comprises an entrance pupil area, a first expanded pupil area, a second expanded pupil area and an exit pupil area, wherein the first expanded pupil area is positioned on the horizontal side of the entrance pupil area, the second expanded pupil area is positioned on the lower side of the entrance pupil area, and the exit pupil area is positioned at the position where the light paths of the first expanded pupil area and the second expanded pupil area are overlapped;

the entrance pupil area is provided with a first entrance pupil grating and a second entrance pupil grating, the first pupil area is provided with a first pupil expansion grating, the second pupil area is provided with a second pupil expansion grating, and the exit pupil area is provided with a first exit pupil grating and a second exit pupil grating;

the projection light machine is used for emitting first incident light and second incident light with different wavelengths, the first incident light enters the first entrance pupil grating, is diffracted by the first pupil grating, and is emitted by the first exit pupil grating; the second incident light enters the second entrance pupil grating, is diffracted by the second pupil grating and is emitted by the second exit pupil grating; and the first exit pupil light emitted by the first exit pupil grating and the second exit pupil light emitted by the second exit pupil grating are combined in the exit pupil area.

2. The waveguide diffraction device of claim 1, wherein the diffraction waveguide further comprises:

the first light filtering band is arranged between the first pupil expanding area and the entrance pupil area and/or between the first pupil expanding area and the exit pupil area;

and the second light filtering band is arranged between the second pupil expanding area and the entrance pupil area, and/or between the second pupil expanding area and the exit pupil area.

3. The waveguide diffraction device of claim 2, wherein the first incident light is blue light and green light and the second incident light is red light; the first filter band is used for cutting off red light and passing blue light and green light; the second filter band is used to cut off blue and green light and pass red light.

4. The waveguide diffraction device of claim 2, wherein the first filter band has a thickness of 1.5mm to 3mm and the second filter band has a thickness of 1.5mm to 3 mm.

5. The waveguide diffraction device according to claim 1, wherein the grating direction of the first entrance pupil grating is at an angle of 0 ° to the horizontal, and the grating direction of the second entrance pupil grating is at an angle of-90 ° to the horizontal; the included angle between the grating direction of the first pupil expansion grating and the horizontal direction is-135 degrees, and the included angle between the grating direction of the second pupil expansion grating and the horizontal direction is 45 degrees; the included angle between the grating direction of the first exit pupil grating and the horizontal direction is 90 degrees, and the included angle between the grating direction of the second exit pupil grating and the horizontal direction is 180 degrees.

6. The waveguide diffraction device according to claim 1, wherein the entrance pupil region is circular with a diameter of 2.5mm to 7mm, and the grating periods of the first and second entrance pupil gratings are both 300nm to 450 nm;

the first pupil expanding area and the second pupil expanding area are both quadrangles, the maximum width of each quadrangle is 5-10 times of the diameter of the entrance pupil area, the maximum height of each quadrangle is 2-4 times of the diameter of the entrance pupil area, and the height of each quadrangle is gradually increased from the area close to the entrance pupil to the area far away from the entrance pupil area; the grating periods of the first pupil expanding grating and the second pupil expanding grating are both 150 nm-300 nm;

the exit pupil area is rectangular, the length of the rectangle is 80% -90% of the maximum width of the first pupil expansion area, the width of the rectangle is 80% -90% of the maximum width of the second pupil expansion area, and the grating periods of the first exit pupil grating and the second exit pupil grating are 300 nm-450 nm.

7. The waveguide diffraction device of claim 6, wherein the exit pupil region has an aspect ratio of 16:9 or 4: 3.

8. The waveguide diffraction device of claim 1, wherein the projection optics comprise a red light optic, a green light optic and a blue light optic, each being a micro led projection optics, the green light optic and the blue light optic facing the first entrance pupil grating, the red light optic facing the second entrance pupil grating, the display panels of the three optics being in a same plane.

9. The waveguide diffraction device according to claim 1, wherein the projection optical engine is an LCOS projection optical engine, wherein the equivalent back focal plane of the first lens group coincides with the equivalent front focal plane of the second lens group, the LCOS screen is located at the focal plane coincidence position, and the equivalent front focal plane of the first lens group is provided with a red light source and a green blue light source; the exit pupil surface of the projection light machine is provided with a corner prism, a red light source and a green light and blue light source which reflect light to the entrance pupil area by utilizing the corner prism.

10. The waveguide diffraction device of claim 1, wherein the entrance pupil region comprises a first semi-circular entrance pupil region and a second semi-circular entrance pupil region, the first entrance pupil grating being disposed in the first semi-circular entrance pupil region, the second entrance pupil grating being disposed in the second semi-circular entrance pupil region; the intersection line of the first semicircular entrance pupil area and the second semicircular entrance pupil area forms an included angle of 135 degrees with the horizontal direction.

11. The waveguide diffraction device of claim 1, wherein the entrance pupil region comprises a first entrance pupil section, a second entrance pupil section, and a third entrance pupil section, the first entrance grating being formed in the first and second entrance pupil sections, and the second entrance grating being formed in the third entrance pupil section.

12. The waveguide diffraction device according to claim 10 or 11, wherein the light source distribution of the projection light engine corresponds to the distribution of the entrance pupil one by one.

13. Display glasses, characterized in that they comprise a waveguide diffraction device according to any one of claims 1 to 12.

14. The display eyewear of claim 13, wherein the display eyewear comprises two waveguide diffraction devices, wherein the center distance of the exit pupil region of the two waveguide diffraction devices is 60mm to 70 mm.

Technical Field

The application belongs to the technical field of display, and particularly relates to a waveguide diffraction device and display glasses.

Background

With the progress of imaging technology, people have higher and higher requirements on immersive experience, and in recent years, the development of VR/AR technology gradually meets the pursuit of people on visual experience. The head-mounted equipment can liberate both hands of people, reduce the dependence on the screen, and build better visual effect simultaneously. For head-mounted devices, near-eye display is the key to its technology, and imaging quality and thinness are major considerations. The near-to-eye display system generally consists of an image far-near light transmission system, and image pictures sent by an image source are transmitted to human eyes through an optical transmission system. Here, unlike the blocking of the external environment by the VR, the AR needs to have a certain transmittance so that the wearer can see the external environment while seeing the image.

For optical transmission systems, there are many schemes in the industry, such as free space optics, free form optics, and display light guides. The optical waveguide technology is obviously superior to other optical schemes due to the characteristics of a large eye box and the light and thin characteristics of the large eye box, and becomes a mainstream path of each large company.

Currently, most of the mainstream AR glasses use diffractive light waveguide technology, such as Microsoft's first and second generation HoloLens, Magic Leap AR glasses. Due to the low efficiency of light wave diffraction and the selectivity of the grating to the wavelength, the AR glasses mostly adopt 2-3 layers of waveguides to realize color display, each layer of waveguide transmits one color light, and the color light is finally combined at the exit pupil.

Disclosure of Invention

The application provides a waveguide diffraction device and display glasses, which are used for solving the problems that waveguide volume and weight are large and display transmittance is low during color display.

In order to solve the above technical problem, the present application provides a waveguide diffraction device, including: the diffraction waveguide comprises an entrance pupil area, a first expanded pupil area, a second expanded pupil area and an exit pupil area, wherein the first expanded pupil area is positioned on the horizontal side of the entrance pupil area, the second expanded pupil area is positioned on the lower side of the entrance pupil area, and the exit pupil area is positioned at the position where the light paths of the first expanded pupil area and the second expanded pupil area are overlapped; the entrance pupil area is provided with a first entrance pupil grating and a second entrance pupil grating, the first pupil area is provided with a first pupil expansion grating, the second pupil area is provided with a second pupil expansion grating, and the exit pupil area is provided with a first exit pupil grating and a second exit pupil grating; the projection light machine is used for emitting first incident light and second incident light with different wavelengths, the first incident light enters the first entrance pupil grating, is diffracted by the first pupil grating, and is emitted by the first exit pupil grating; the second incident light enters the second entrance pupil grating, is diffracted by the second pupil grating and is emitted by the second exit pupil grating; and the first exit pupil light emitted by the first exit pupil grating and the second exit pupil light emitted by the second exit pupil grating are combined in the exit pupil area.

In one embodiment, the diffractive waveguide further comprises: the first light filtering band is arranged between the first pupil expanding area and the entrance pupil area and/or between the first pupil expanding area and the exit pupil area; and the second light filtering band is arranged between the second pupil expanding area and the entrance pupil area, and/or between the second pupil expanding area and the exit pupil area.

In one embodiment, the first incident light is blue light and green light, and the second incident light is red light; the first filter band is used for cutting off red light and passing blue light and green light; the second filter band is used to cut off blue and green light and pass red light.

In one embodiment, the first filter band has a thickness of 1.5mm to 3mm and the second filter band has a thickness of 1.5mm to 3 mm.

In one embodiment, the angle between the grating direction of the first entrance pupil grating and the horizontal direction is 0 °, and the angle between the grating direction of the second entrance pupil grating and the horizontal direction is-90 °; the included angle between the grating direction of the first pupil expansion grating and the horizontal direction is-135 degrees, and the included angle between the grating direction of the second pupil expansion grating and the horizontal direction is 45 degrees; the included angle between the grating direction of the first exit pupil grating and the horizontal direction is 90 degrees, and the included angle between the grating direction of the second exit pupil grating and the horizontal direction is 180 degrees.

In one embodiment, the entrance pupil area is a circle with a diameter of 2.5mm to 7mm, and the grating periods of the first entrance pupil grating and the second entrance pupil grating are both 300nm to 450 nm; the first pupil expanding area and the second pupil expanding area are both quadrangles, the maximum width of each quadrangle is 5-10 times of the diameter of the entrance pupil area, the maximum height of each quadrangle is 2-4 times of the diameter of the entrance pupil area, and the height of each quadrangle is gradually increased from the area close to the entrance pupil to the area far away from the entrance pupil area; the grating periods of the first pupil expanding grating and the second pupil expanding grating are both 150 nm-300 nm; the exit pupil area is rectangular, the length of the rectangle is 80% -90% of the maximum width of the first pupil expansion area, the width of the rectangle is 80% -90% of the maximum width of the second pupil expansion area, and the grating periods of the first exit pupil grating and the second exit pupil grating are 300 nm-450 nm.

In one embodiment, the aspect ratio of the exit pupil region is 16:9 or 4: 3.

In one embodiment, the projection light machines include a red light machine, a green light machine and a blue light machine, which are Micro LED projection light machines, the green light machine and the blue light machine are aligned with the first entrance pupil grating, the red light machine is aligned with the second entrance pupil grating, and the display panels of the three light machines are on the same plane.

In one embodiment, the projection optical machine is an LCOS projection optical machine, wherein an equivalent rear focal surface of the first lens group coincides with an equivalent front focal surface of the second lens group, the LCOS screen is located at the position where the focal surfaces coincide, and the equivalent front focal surface of the first lens group is provided with a red light source and a green blue light source; the exit pupil surface of the projection light machine is provided with a corner prism, a red light source and a green light and blue light source which reflect light to the entrance pupil area by utilizing the corner prism.

In one embodiment, the entrance pupil region comprises a first semicircular entrance pupil region and a second semicircular entrance pupil region, the first entrance pupil grating is arranged in the first semicircular entrance pupil region, and the second entrance pupil grating is arranged in the second semicircular entrance pupil region; the intersection line of the first semicircular entrance pupil area and the second semicircular entrance pupil area forms an included angle of 135 degrees with the horizontal direction.

In one embodiment, the entrance pupil region includes a first entrance pupil section, a second entrance pupil section, and a third entrance pupil section, the first incident grating is formed in the first entrance pupil section and the second entrance pupil section, and the second incident grating is formed in the third entrance pupil section.

In one embodiment, the light source distribution of the projector is in one-to-one correspondence with the distribution of the entrance pupil area.

In order to solve the above technical problem, the present application provides a display glasses, which includes the above waveguide diffraction device.

In one embodiment, the display glasses include two waveguide diffraction devices, wherein the center distance of the exit pupil area of the two waveguide diffraction devices is 60mm to 70 mm.

Different from the prior art, this application waveguide diffraction device includes diffraction waveguide and projection ray apparatus, and wherein the projection ray apparatus beam splitting just exports the light of different wavelengths, and is formed with entrance pupil district, first pupil expanding district, second pupil expanding district and exit pupil district on the diffraction waveguide, provides two propagation path for the light of different wavelengths, and closes at the exit pupil district at last and restraint, then realizes the color display. The waveguide diffraction device is simple in structure, color display can be achieved through the single waveguide, and the transmittance is high.

Drawings

The above and other objects, features and advantages of exemplary embodiments of the present disclosure will become readily apparent from the following detailed description read in conjunction with the accompanying drawings. Several embodiments of the present disclosure are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar or corresponding parts and in which:

FIG. 1 is a schematic structural diagram of a first embodiment of a waveguide diffraction device according to the present application;

FIG. 2 is a schematic diagram of the structure of a diffractive waveguide in the waveguide diffraction apparatus of FIG. 1;

FIG. 3 is a schematic diagram of a projection optical engine in the waveguide diffraction device shown in FIG. 1;

FIG. 4 is a dimensional schematic of the diffractive waveguide of FIG. 2;

FIG. 5 is a schematic diagram of a pupil splitting optical path of the projection engine shown in FIG. 3;

FIG. 6 is a schematic diagram of the path of red light in the diffractive waveguide of FIG. 2;

figure 7 is a schematic view of another configuration of the entrance pupil region of the diffractive waveguide of figure 2;

FIG. 8 is a schematic structural diagram of a second embodiment of a waveguide diffraction device according to the present application;

FIG. 9 is a schematic diagram of a light engine of the waveguide diffraction device shown in FIG. 8;

FIG. 10 is a schematic structural diagram of an embodiment of eyewear shown in the present application.

Detailed Description

The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are some, but not all embodiments of the present disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.

The waveguide diffraction device adopts the single-chip waveguide as the substrate, utilizes the double-expanding pupil area to carry out color partition and the partition pupil characteristic of the projector to realize color display, simultaneously ensures color uniformity and light-emitting brightness, and improves the field angle. One pupil expanding area in the diffraction waveguide is responsible for the propagation of color light with the wavelength band of 635nm, and the other pupil expanding area is responsible for the propagation of color light with the wavelength bands of 470nm and 520nm, and finally the color light is combined in an exit pupil area to generate a color pattern. Diffraction gratings in two directions are arranged in an entrance pupil area of the waveguide sheet, and a pupil splitting optical machine is matched to enable image sources of different colors to fall on the gratings in different directions, so that color partitioning is achieved.

Referring specifically to fig. 1-3, the diffractive waveguide 100 can be disposed in a frame 200, and the frame 200 is used to constrain the waveguide sheet and protect it. The diffractive waveguide 100 includes an entrance pupil region 110, a first expanded pupil region 121, a second expanded pupil region 122 and an exit pupil region 130, wherein a first filter band 141 is disposed at the edge of the first expanded pupil region 121, and a second filter band 142 is disposed at the edge of the second expanded pupil region 122. The LCOS projector 300 is mounted to the left of the entrance pupil region 110 and couples the light beam into the diffractive waveguide 100 using a corner prism 340. Two entrance pupil gratings are arranged in the entrance pupil area 110, are divided by an angle of 45 degrees, and the grating direction of the upper right area is a horizontal direction, so that the light beams are deflected to the first pupil expanding area 121; the grating direction in the lower left region is vertical, deflecting the light beam towards the second pupil expanding region 122. The red light is projected to the lower left area of the entrance pupil area 110 by using the pupil splitting principle of the projector light machine 300, so that the red light is transmitted to the exit pupil area 130 through the second pupil expanding area 122; the green and blue light is projected to the upper right region of the entrance pupil region 110, propagates through the first pupil expanding region 121 to the exit pupil region 130, and is finally combined to form a color image.

Referring to fig. 4, the entrance pupil region 110 is located at the upper left corner of the diffractive waveguide 100, which may be located at the upper right corner of the diffractive waveguide. Here, the use of the left eye is taken as an example. Two directional diffraction gratings are arranged in the entrance pupil area 110 and are divided by an angle of 45 degrees, the upper right corner of the entrance pupil area 110 is a first entrance pupil grating, the grating direction is V11, the included angle θ 11 with the horizontal line is 0 degree, the grating period is d11, and the first entrance pupil area 121 is responsible for transmitting the color light of the blue light and the green light waveband; the lower left corner of the entrance pupil region 110 is a second entrance pupil grating, the grating direction is V12, the angle θ 12 between the horizontal line and the horizontal line is-90 °, the grating period is d12, and the second entrance pupil region 122 is responsible for transmitting the color light in the red wavelength band.

The first pupil expanding region 121 is located on the right side of the entrance pupil region 110, and is provided with a first pupil expanding grating, the grating direction is V21, the included angle θ 21 with the horizontal line is-135 °, the grating period is d21, and a first light filtering strip 141 is arranged on the periphery of the first pupil expanding region 121 and is responsible for filtering red light; the second pupil expanding region 122 is located below the entrance pupil region 110, and is provided with a second pupil expanding grating, the grating direction is V22, the included angle θ 22 between the grating direction and the horizontal line is 45 °, the grating period is d22, and a second light filtering band 142 is arranged on the periphery of the second pupil expanding region 122 and is responsible for filtering blue light and green light.

The exit pupil region 130 is located below the first pupil expanding region 121 and to the right of the second pupil expanding region 122, and is located within the optical path coverage of the two pupil expanding regions, i.e. the overlapping region of the two optical paths. A first exit pupil grating and a second exit pupil grating are arranged in the exit pupil region 130, the grating direction of the first exit pupil grating is V31, the included angle θ 31 between the first exit pupil grating and the horizontal line is 90 °, the grating period is d31, and the first exit pupil grating is responsible for coupling the blue light and the green light in the image source out of the waveguide; the second exit pupil grating has a grating direction V32, an angle θ 32 of 180 ° to the horizontal, and a grating period d32, and is responsible for coupling the red light in the image source out of the waveguide. The three color lights are combined in the exit pupil area to form a color image.

The diameter D of the entrance pupil area 110 is 2.5-7 mm, and the grating periods D11 and D12 of the first entrance pupil grating and the second entrance pupil grating are 300-450 nm.

The first pupil expanding region 121 is a quadrilateral with a maximum width W1 and a maximum height H1, wherein the maximum width W1 may be 5 to 10 times of the entrance pupil diameter D, the maximum height may be 2 to 4 times of the entrance pupil diameter D, the height of the side close to the entrance pupil region 110 is the lowest, the height of the side far away from the entrance pupil region 110 is the highest, and the grating period D21 of the first pupil expanding grating is 150 to 300 nm.

The second pupil expanding region 122 is a quadrilateral with a maximum width W2 and a maximum height H2, wherein the maximum width W2 may be 5 to 8 times of the entrance pupil diameter D, the maximum height may be 2 to 4 times of the entrance pupil diameter D, the height of the side close to the entrance pupil region 110 is the lowest, the height of the side far away from the entrance pupil region 110 is the highest, and the grating period D22 of the second pupil expanding grating is 150 to 300 nm.

The first light filtering band 141 is arranged at the outer edge of the first pupil expanding area 121, and the thickness TH1 is 1.5-3 mm; the second light filtering band 142 is arranged at the outer edge of the second pupil expanding area 122, and the thickness TH2 is 1.5-3 mm.

The exit pupil region 130 has a length L and a width W, the length L may be 80% to 90% of W1, the width W may be 80% to 90% of W2, and L: W is 16:9 or L: W is 4:3, the grating periods d31 and d32 of the first and second exit pupil gratings are in the range of 300 to 450 nm.

The projector 300 of the afocal system is disposed on the left side of the entrance pupil region 110, and deflects the light beam by the corner prism 340 and enters the entrance pupil region 110. The light source of the projector 300 is separately arranged, and the light source 301 is arranged at the lower left and is responsible for red light illumination; the light source 302 is arranged at the upper right and is responsible for the illumination of blue and green light. According to the 4f afocal system principle, the red light will enter the second entrance pupil grating and propagate through the second pupil expanding region 122 to the exit pupil region 130; the blue and green light will enter the first entrance pupil grating and propagate through the first pupil expanding region 121 to the exit pupil region 130. The three colors of light combine in the exit pupil region 130 to form a color image.

Referring to fig. 5, the projection light 300 includes a Polarization Beam Splitter (PBS)320 for splitting the light according to the polarization state of the light; and a Liquid Crystal On Silicon (LCOS)330 as a projection panel for reading in an image, and further including a first lens 311 and a second lens 312. The back focal plane of the first lens group 311 coincides with the front focal plane of the second lens group 312 to form an afocal system, wherein the exit pupil plane of the light source is located at the front focal plane of the first lens group 311, the LCOS is located at the coincidence position of the back focal plane of the first lens group and the front focal plane of the second lens group, and the exit pupil plane of the optical engine is located at the back focal plane of the second lens group. In the system, because the light source and the LCOS are respectively arranged at the front focal plane and the rear focal plane of the first lens group 311, each pixel on the LCOS can be uniformly illuminated, meanwhile, the LCOS is also arranged at the front focal plane of the second lens group 312, the second lens group can collimate and emit light to each pixel on the LCOS, and a beam waist is formed at the exit pupil plane, namely the rear focal plane of the second lens group, the energy density of the light spot is the largest at the position, the area is the smallest, and each point contains all information of the projected image, so as long as light passes through, complete image information can be projected no matter how the light is shielded, the shielding of the exit pupil only reduces the image brightness, and the image information cannot be shielded. Based on the characteristic, a plurality of aperture diaphragms can be arranged on the exit pupil surface, the original image can be divided into sub-images with the same number as the aperture diaphragms, each sub-image comprises complete information of the original image, and the sub-images are respectively coupled into different entrance pupil channels, so that the images can be transmitted towards different directions at the same time.

Meanwhile, if a plurality of non-overlapping sub-light sources are disposed on the front focal plane of the first lens assembly 311, each sub-light source is symmetrically imaged on the exit pupil plane of the system, i.e. the rear focal plane of the second lens assembly 312, the center of symmetry is the rear focal point of the first lens assembly, the center-to-center distance between the images is proportional to the center-to-center distance between the light emitting surfaces of the light sources, the magnification factor depends on the focal length of the second lens assembly, i.e. β ═ f _2/f _1, where β is the vertical axis magnification factor, f _2 is the equivalent focal length of the second lens assembly, and f _1 is the equivalent focal length of the first lens assembly. Similarly, the object image at the exit pupil plane is also the beam waist of the projection beam, and each image point carries the complete information of the LCOS image. Coupling each object image separately into a different entrance pupil channel also allows for simultaneous image transmission in different directions.

Referring to fig. 6, under the action of the pupil-splitting optical machine, the red light portion of the image source is coupled into the waveguide from the second entrance pupil grating. When the light beam contacts the grating, a diffraction phenomenon (let us assume that + 1 order light is transmitted downwards and-1 order light is transmitted upwards) is generated, and the + 1 order diffraction light is deflected to an exit pupil area through the second pupil expansion grating and is coupled out of the waveguide under the action of the exit pupil grating; and part of light of the-1 level light contacts the first entrance pupil grating when the light is transmitted, so that the light is deflected to the first expanded pupil area, and the crosstalk light can influence the uniformity of colors, so that filter bands are arranged between the first expanded pupil area and the entrance pupil area and between the first expanded pupil area and the exit pupil area, and the red light crosstalk is prevented from influencing the imaging quality. Similarly, light filtering bands aiming at blue light and green light are arranged between the second pupil expanding area and the entrance pupil area and between the second pupil expanding area and the exit pupil area, and the crosstalk of the chromatic light is also prevented.

The color partition and the optical machine pupil need to be matched for use, if the optical machine pupil is not adopted, all light beams are totally projected to the surface of the entrance pupil area, half energy can be totally lost due to wrong diffraction directions, and therefore the energy utilization rate can be reduced to 25%.

The present embodiment is a single-waveguide diffraction device for display glasses, i.e. AR glasses, and includes a diffraction waveguide plate 100 and an LCOS projector 300. The diffractive waveguide sheet includes an entrance pupil region 110, a first expanded pupil region 121, a second expanded pupil region 122, an exit pupil region 130, and first and second filter bands 141 and 142. The entrance pupil area is positioned at the upper left corner of the waveguide sheet, the first pupil expanding area is positioned at the right side of the entrance pupil area, the second pupil expanding area is positioned below the entrance pupil area, the exit pupil area is positioned below the first pupil expanding area and at the right side of the second pupil expanding area, and the overlapping area of the optical paths of the two pupil expanding areas. Wherein the first filter band surrounds the left side and below of the first expanded pupil zone and the second filter band surrounds the right side and above of the second expanded pupil zone.

The LCOS projection optical machine adopts an afocal system, the rear focal plane of the first lens group 311 coincides with the front focal plane of the second lens group 312, the light source plane is on the front focal plane of the first lens group, the LCOS screen is located at the coincidence position of the rear focal plane of the first lens group and the front focal plane of the second lens group, and the exit pupil plane is on the rear focal plane of the second lens group. In the light source plane, a first light source 301 and a second light source 302 are included, wherein the first light source is a separate red light source and the second light source is an integrated light source of green light and blue light. The projection optical machine is arranged on the left side of the entrance pupil area, and the exit pupil of the optical machine is provided with a corner prism for projecting image information to the entrance pupil area.

By utilizing the pupil splitting characteristic of an afocal system, green light and blue light project image information to a first entrance pupil grating of an entrance pupil area, and the first entrance pupil grating is first incident light; the first incident light is diffracted after contacting the first entrance pupil grating, and the diffracted light is coupled into the waveguide and propagates to the first pupil expanding area through total internal reflection, and the first pupil expanding area is first entrance pupil light; the first entrance pupil light is diffracted after contacting the first pupil expansion grating, and the diffracted light propagates towards the exit pupil area through total internal reflection, so that the first entrance pupil light is first pupil expansion light; the first pupil expanding light is diffracted after contacting the exit pupil grating, and the diffracted light is coupled out of the waveguide and propagates towards human eyes, and the first pupil expanding light is the first exit pupil light.

Meanwhile, the red light projects the image information to a second entrance pupil grating of the entrance pupil area, and the second entrance pupil grating is second incident light; the second incident light is diffracted after contacting the second entrance pupil grating, and the diffracted light is coupled into the waveguide and propagates to a second pupil expanding area through total internal reflection, which is second entrance pupil light; the second entrance pupil light is diffracted after contacting the second pupil expansion grating, and the diffracted light is propagated by total internal reflection towards the exit pupil area, and the diffracted light is the second pupil expansion light; the second pupil expanding light is diffracted after contacting the exit pupil grating, and the diffracted light is coupled out of the waveguide and propagates towards human eyes, and the second pupil expanding light is the second exit pupil light.

The first exit pupil light and the second exit pupil light are combined in the exit pupil area, and finally a color image is formed.

Because the entrance pupil grating is divided by an angle of 45 degrees, part of diffracted light of the first incident light can act with the second entrance pupil grating so as to enter the second pupil expanding area, and crosstalk is generated. Therefore, a first light filtering band is arranged between the first pupil expanding area and the entrance pupil area and between the first pupil expanding area and the exit pupil area to prevent the crosstalk of the red light; and second light filtering bands are arranged between the second pupil expanding area and the entrance pupil area and between the second pupil expanding area and the exit pupil area so as to prevent crosstalk of the green light and the blue light.

Alternatively, the entrance pupil area can be set as three subareas, corresponding to the light source positions of the projection light machine, and respectively responsible for the coupling of one color light, see fig. 7.

The invention utilizes the color subarea with double expanding pupils to divide the three primary color lights of the synthesized color image into two areas on the same waveguide slice, thereby improving the color uniformity; the color information of the image source is projected to different diffraction areas by utilizing the optical machine pupil division so as to improve the utilization rate of energy. The integral structure reduces the thickness and the weight of the waveguide sheet, so that the color fusion is more uniform, the energy conversion efficiency is improved, and the color crosstalk can be better inhibited by introducing the filter band.

The existing AR waveguide technology basically adopts the design of multiple waveguide sheets to realize color display of images, and different waveguide sheets are responsible for different color lights. The invention realizes the color display of images by utilizing a single diffraction waveguide, and sets double light paths on the same waveguide by utilizing the color partition and optical machine pupil division technology, wherein red light passes through one light path, green light and blue light pass through the other light path, and finally the beams are combined on the exit pupil surface to realize the color display. The thickness and the weight of the waveguide sheet are reduced, the color fusion is more uniform, the energy conversion efficiency is improved, and the color crosstalk can be better inhibited by introducing the filter band.

In this embodiment, an afocal system projection optical machine based on an LCOS panel is adopted, red light is projected to the second entrance pupil grating surface by using the pupil splitting characteristic of the projection optical machine, green light and blue light are projected to the first entrance pupil grating surface, so that the light energy utilization rate is improved, different colored lights are respectively projected to gratings in corresponding diffraction directions, and the light energy utilization rate is improved by 1 time compared with that before pupil splitting.

Please refer to fig. 8-9, which are related schematic diagrams of a second embodiment of a waveguide diffraction device according to the present application. Comprises a diffraction waveguide sheet 100 and a Micro LED optical machine 400. The diffractive waveguide sheet includes an entrance pupil region 110, a first expanded pupil region 121, a second expanded pupil region 122, an exit pupil region 130, and first and second filter bands 141 and 142. The entrance pupil area is positioned at the upper left corner of the waveguide sheet, the first pupil expanding area is positioned at the right side of the entrance pupil area, the second pupil expanding area is positioned below the entrance pupil area, the exit pupil area is positioned below the first pupil expanding area and at the right side of the second pupil expanding area, and the overlapping area of the optical paths of the two pupil expanding areas. Wherein the first filter band surrounds the left side and below of the first expanded pupil zone and the second filter band surrounds the right side and above of the second expanded pupil zone.

The projection light machine adopts Micro LED panel technology which is self-luminous technology, and no extra light source is needed, so the volume can be made very small. However, for technical reasons, the Micro LED can only display one color light, so the invention adopts a mode of connecting three Micro LED light machines in parallel to realize color display of images, as shown in fig. 9. The display panels of the three optical machines are on the same plane. The Micro LED light engine is arranged right opposite to the entrance pupil region, and the light engine is composed of a display panel 40X (X ═ 1,2,3) and a projection lens 41X (X ═ 1,2,3), wherein the display panel 401 is responsible for displaying red images and projecting image sources to the position of the second entrance pupil grating, and 402 and 403 are responsible for displaying green and blue images respectively and projecting image sources to the position of the first entrance pupil grating.

In the Micro LED optical machine, green light and blue light project image information to a first entrance pupil grating in an entrance pupil area, and the first entrance pupil grating is first incident light; the first incident light is diffracted after contacting the first entrance pupil grating, and the diffracted light is coupled into the waveguide and propagates to the first pupil expanding area through total internal reflection, and the first pupil expanding area is first entrance pupil light; the first entrance pupil light is diffracted after contacting the first pupil expansion grating, and the diffracted light propagates towards the exit pupil area through total internal reflection, so that the first entrance pupil light is first pupil expansion light; the first pupil expanding light is diffracted after contacting the exit pupil grating, and the diffracted light is coupled out of the waveguide and propagates towards human eyes, and the first pupil expanding light is the first exit pupil light.

Meanwhile, the red light projects the image information to a second entrance pupil grating of the entrance pupil area, and the second entrance pupil grating is second incident light; the second incident light is diffracted after contacting the second entrance pupil grating, and the diffracted light is coupled into the waveguide and propagates to a second pupil expanding area through total internal reflection, which is second entrance pupil light; the second entrance pupil light is diffracted after contacting the second pupil expansion grating, and the diffracted light is propagated by total internal reflection towards the exit pupil area, and the diffracted light is the second pupil expansion light; the second pupil expanding light is diffracted after contacting the exit pupil grating, and the diffracted light is coupled out of the waveguide and propagates towards human eyes, and the second pupil expanding light is the second exit pupil light.

The first exit pupil light and the second exit pupil light are combined in the exit pupil area, and finally a color image is formed.

Because the entrance pupil grating is divided by an angle of 45 degrees, part of diffracted light of the first incident light can act with the second entrance pupil grating so as to enter the second pupil expanding area, and crosstalk is generated. Therefore, a first light filtering band is arranged between the first pupil expanding area and the entrance pupil area and between the first pupil expanding area and the exit pupil area to prevent the crosstalk of the red light; and second light filtering bands are arranged between the second pupil expanding area and the entrance pupil area and between the second pupil expanding area and the exit pupil area so as to prevent crosstalk of the green light and the blue light.

Optionally, the entrance pupil area may be set as three subareas, which correspond to the light source positions of the projection light machine one by one and are respectively responsible for coupling of one color light.

In addition to the above beneficial effects, in this embodiment, color partitioning is realized by connecting three Micro LED optical machines in parallel, the red light Micro LEDs are projected onto the second entrance pupil grating surface, the green light Micro LEDs and the blue light Micro LEDs are projected onto the first entrance pupil grating surface, and different colored lights are respectively projected onto the gratings in the corresponding diffraction directions, so that the light energy utilization rate is increased by 1 time compared with that before pupil partitioning.

This application still provides a show glasses, is about to above-mentioned monolithic waveguide diffraction device be used for binocular display, sets up two waveguide pieces through the mirror image and in order to realize binocular display, and wherein the central distance in two exit pupil districts is between 60 ~ 70mm, for the interpupillary distance of people's eyes.

In the above description of the present specification, the terms "fixed," "mounted," "connected," or "connected," and the like, are to be construed broadly unless otherwise expressly specified or limited. For example, with the term "coupled", it can be fixedly coupled, detachably coupled, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship. Therefore, unless the specification explicitly defines otherwise, those skilled in the art can understand the specific meaning of the above terms in the present application according to specific circumstances.

From the above description of the present specification, those skilled in the art will also understand the terms used below, terms indicating orientation or positional relationship such as "upper", "lower", "front", "rear", "left", "right", "length", "width", "thickness", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", "central", "longitudinal", "transverse", "clockwise" or "counterclockwise" and the like are based on the orientation or positional relationship shown in the drawings of the present specification, it is used for convenience in explanation of the disclosure and for simplicity in description, and does not explicitly show or imply that the devices or elements involved must be in the particular orientation described, constructed and operated, therefore, the above terms of orientation or positional relationship should not be interpreted or construed as limiting the present application.

In addition, the terms "first" or "second", etc. used in this specification are used to refer to numbers or ordinal terms for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present specification, "a plurality" means at least two, for example, two, three or more, and the like, unless specifically defined otherwise.

While various embodiments of the present application have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous modifications, changes, and substitutions will occur to those skilled in the art without departing from the spirit and scope of the present application. It should be understood that various alternatives to the embodiments of the application described herein may be employed in practicing the application. The following claims are intended to define the scope of the application and, accordingly, to cover module compositions, equivalents, or alternatives falling within the scope of these claims.