阅读说明：本技术 一种光波导及近眼显示系统 (Optical waveguide and near-to-eye display system ) 是由 宋强 郭晓明 黄浩 马国斌 于 2020-07-14 设计创作，主要内容包括：本发明实施例涉及光学技术领域,特别涉及一种光波导及近眼显示系统。本发明实施例中提供的光波导包括波导基底、耦入区域、耦出区域和回光区域：耦入区域、耦出区域以及回光区域设置在所述波导基底上,耦入区域用于耦入带有图像信息的光束,耦出区域用于耦出所述带有图像信息的光束,回光区域用于反向回传所述带有图像信息的光束至所述耦出区域；所述耦出区域包括至少三侧边缘,所述耦出区域的至少一侧边缘设置有所述回光区域,当图像光束传播到耦出区域边缘时,由于回光区域的作用,部分图像光束会反向传播回到耦出区域,再经耦出区域耦出至人眼,从而提高二维扩展衍射光波导的能量利用率。(The embodiment of the invention relates to the technical field of optics, in particular to an optical waveguide and a near-to-eye display system. The optical waveguide provided in the embodiment of the present invention includes a waveguide substrate, a coupling-in region, a coupling-out region, and a light return region: the light-in area, the light-out area and the light-returning area are arranged on the waveguide substrate, the light-in area is used for coupling in the light beam with the image information, the light-out area is used for coupling out the light beam with the image information, and the light-returning area is used for returning the light beam with the image information to the light-out area in a reverse direction; the coupling-out area comprises at least three side edges, the light return area is arranged on at least one side edge of the coupling-out area, and when the image light beams are transmitted to the edge of the coupling-out area, partial image light beams can reversely transmit back to the coupling-out area under the action of the light return area and then are coupled out to human eyes through the coupling-out area, so that the energy utilization rate of the two-dimensional expanded diffraction light waveguide is improved.)

1. An optical waveguide comprising a waveguide substrate, a coupling-in region, a coupling-out region and a light return region:

the coupling-in area, the coupling-out area and the light returning area are arranged on the waveguide substrate, the coupling-in area is used for coupling in the light beam with the image information, the coupling-out area is used for coupling out the light beam with the image information, and the light returning area is used for returning the light beam with the image information to the coupling-out area;

the light coupling-out region comprises at least three side edges, and at least one side edge of the light coupling-out region is provided with the light return region.

2. The optical waveguide of claim 1, wherein at least three edges of the coupling-out region, except for an edge facing the coupling-in region, are provided with the light return regions.

3. The optical waveguide of claim 1, wherein a first side edge of at least three side edges of the coupling-out region faces away from the coupling-in region, the first side edge being provided with the light return region.

4. The optical waveguide of claim 3, wherein the first side edge has adjacent second and third side edges, the second and/or third side edges also being provided with the light return region.

5. The optical waveguide of any of claims 2-4, wherein the light return region is disposed adjacent to an edge of the coupling-out region.

6. The optical waveguide of any of claims 2-4, wherein a gap exists between the edge of the coupling-out region and the light return region.

7. The optical waveguide of claim 1, wherein the width of the light returning region is D, the thickness of the waveguide substrate is D, the maximum total reflection angle of the light beam when propagating through the waveguide substrate by total reflection is θ, and the relationship between the three is: d > 2D tan θ.

8. The optical waveguide of claim 1, wherein the surface of the light return region is coated.

9. The optical waveguide of claim 1, wherein the coupling-in region has one of a mirror, a prism, a free-form surface structure, a grating structure, a super-surface structure, a volume hologram structure, or a resonant grating structure, and the coupling-out region and the light returning region have one of a two-dimensional grating structure, a super-surface structure, a volume hologram structure, or a resonant grating structure.

10. A near-eye display system, comprising: a micro-projector, and an optical waveguide according to any of claims 1-9.

Technical Field

The embodiment of the invention relates to the technical field of optics, in particular to an optical waveguide and a near-to-eye display system.

Background

Currently, in AR (Augmented Reality) devices, the relief grating waveguide technology is gaining wide attention. Due to the convenience of nanoimprint, and compared with other waveguide schemes, the embossed grating waveguide scheme has the advantages of large field of view and large eye movement range, and the embossed grating waveguide scheme is increasingly widely researched.

The existing embossed grating waveguide scheme mainly includes a waveguide scheme based on a one-dimensional grating and a waveguide scheme based on a two-dimensional grating, wherein the two-dimensional grating waveguide scheme includes an optical waveguide substrate, and an incoupling grating and an outcoupling grating which are arranged on the optical waveguide substrate, an image light beam emitted by an image light source is coupled into the optical waveguide substrate through diffraction of the incoupling grating and is propagated in the optical waveguide substrate in a total reflection manner, and the outcoupling grating is used for diffracting and coupling out the image light in the optical waveguide substrate for a user to watch. However, when the image light beam propagates to the edge of the coupled-out grating region, the partial image light beam is not completely coupled out due to the absence of the function of the coupled-out grating, and the energy utilization rate is not good, so that the energy utilization rate of the two-dimensional expanded diffraction optical waveguide is very urgent to improve.

Disclosure of Invention

In view of the foregoing drawbacks of the prior art, an object of the embodiments of the present invention is to provide a two-dimensional extended diffractive optical waveguide and a near-eye display system capable of improving energy utilization.

The purpose of the embodiment of the invention is realized by the following technical scheme:

in order to solve the above technical problem, in a first aspect, an embodiment of the present invention provides an optical waveguide, including a waveguide substrate, a coupling-in region, a coupling-out region, and a light returning region:

the coupling-in area, the coupling-out area and the light returning area are arranged on the waveguide substrate, the coupling-in area is used for coupling in the light beam with the image information, the coupling-out area is used for coupling out the light beam with the image information, and the light returning area is used for returning the light beam with the image information to the coupling-out area;

the light coupling-out region comprises at least three side edges, and at least one side edge of the light coupling-out region is provided with the light return region.

In some embodiments, the light return regions are disposed on at least three side edges of the coupling-out region except for an edge facing the coupling-in region.

In some embodiments, of at least three side edges of the coupling-out region, a first side edge faces away from the coupling-in region, and the first side edge is provided with the light return region.

In some embodiments, the first side edge has adjacent second and third side edges, the second and/or third side edges also being provided with the light return area.

In some embodiments, the light returning area is disposed at an edge of the coupling-out area.

In some embodiments, there is a gap between the edge of the coupling-out region and the light return region.

In some embodiments, the width of the light returning region is D, the thickness of the waveguide substrate is D, and the maximum total reflection angle of the light beam when propagating through the waveguide substrate by total reflection is θ, where the three satisfy the following relationship: d > 2D tan θ.

In some embodiments, the surface of the light return area is provided with a coating layer.

In some embodiments, the structure of the coupling-in region is one of a mirror, a prism, a free-form surface structure, a grating structure, a super-surface structure, a volume hologram structure, or a resonant grating structure, and the light return region and the coupling-out region are one of a two-dimensional grating structure, a super-surface structure, a volume hologram structure, or a resonant grating structure.

In order to solve the above technical problem, in a second aspect, an embodiment of the present invention provides a near-eye display system, including: a micro-projector light engine, and an optical waveguide as described above in relation to the first aspect.

Compared with the prior art, the invention has the beneficial effects that: in contrast to the state of the art, an embodiment of the present invention provides an optical waveguide applied to a near-eye display system, the optical waveguide including a waveguide substrate, a coupling-in region, a coupling-out region, and a light return region: the light-in area, the light-out area and the light-returning area are arranged on the waveguide substrate, the light-in area is used for coupling in the light beam with the image information, the light-out area is used for coupling out the light beam with the image information, and the light-returning area is used for returning the light beam with the image information to the light-out area in a reverse direction; the coupling-out area comprises at least three side edges, the light return area is arranged on at least one side edge of the coupling-out area, and when the image light beams are transmitted to the edge of the coupling-out area, partial image light beams can reversely transmit back to the coupling-out area under the action of the light return area and then are coupled out to human eyes through the coupling-out area, so that the energy utilization rate of the two-dimensional expanded diffraction light waveguide is improved.

Drawings

One or more embodiments are illustrated by the accompanying figures in the drawings that correspond thereto and are not to be construed as limiting the embodiments, wherein elements/modules and steps having the same reference numerals are represented by like elements/modules and steps, unless otherwise specified, and the drawings are not to scale.

Fig. 1 is a schematic structural diagram of a near-eye display system according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of an optical waveguide according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of an optical waveguide according to a second embodiment of the present invention;

fig. 4 is a schematic structural diagram of an optical waveguide according to a third embodiment of the present invention;

fig. 5 is a schematic structural diagram of an optical waveguide according to a fourth embodiment of the present invention;

fig. 6 is a schematic structural diagram of an optical waveguide according to a fifth embodiment of the present invention;

fig. 7 is a schematic structural diagram of a light return region of an optical waveguide according to an embodiment of the present invention;

fig. 8 is an enlarged schematic view of the structure of fig. 7.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

In order to facilitate an understanding of the present application, the present application is described in more detail below with reference to the accompanying drawings and specific embodiments. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Furthermore, the terms "upper", "lower", "left", "right", and the like, as used herein, indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

It should be noted that, if not conflicted, the various features of the embodiments of the invention may be combined with each other within the scope of protection of the present application. In addition, although the functional blocks are divided in the device diagram, in some cases, the blocks may be divided differently from those in the device. Further, the terms "first," "second," and the like, as used herein, do not limit the data and the execution order, but merely distinguish the same items or similar items having substantially the same functions and actions.

The optical waveguide and near-eye display system of the present invention are specifically described and illustrated below.

In a first aspect, the present invention provides an optical waveguide, referring to fig. 1, the optical waveguide includes a waveguide substrate 4, a coupling-in region 1, a coupling-out region 2, and a light returning region 3: an incoupling area 1, an outcoupling area 2 and a light returning area 3 are arranged on the waveguide substrate 4, the incoupling area 1 is used for incoupling the light beam with image information, the outcoupling area 2 is used for outcoupling the light beam with image information, and the light returning area 3 is used for returning the light beam with image information back to the outcoupling area 2.

The light returning area 3 can be arranged on the surface of the waveguide substrate 4 or inside the waveguide substrate, and can also reversely return the light beam with the image information to the coupling-out area 2.

The structure of the coupling-in area 1 is one of a reflector, a prism, a free-form surface structure, a grating structure, a super-surface structure, a volume holographic structure or a resonance grating structure, and the structures of the coupling-out area 2 and the light returning area 3 are one of a two-dimensional grating structure, a super-surface structure, a volume holographic structure or a resonance grating structure.

Referring to fig. 2, the coupling-out region 2 includes at least three side edges, and a light-returning region 3 is disposed at least one side edge of the coupling-out region 2. In practical applications, the shape of the coupling-in area 1 is not limited to the circular shape shown in the figure, and may be a polygon or an irregular shape; meanwhile, the shape of the coupling-out area 2 is not limited to the polygon shown in the figure, and may be other polygons or irregular shapes, and the shape of the coupling-in area 1 and the shape of the coupling-out area 2 may be set according to actual needs, and need not be limited by the embodiment of the present invention.

In some embodiments, referring to fig. 3, at least three side edges of the coupling-out area 2 are provided with the light return area 3 at other edges of the coupling-out area 2 except the edge facing the coupling-in area 1. In practical applications, in order to reduce the processing cost and the processing difficulty, the light return region 3 may not be disposed near the edge of the coupling-in region 1.

In other embodiments, referring to fig. 2 again, a first side edge of the at least three side edges of the coupling-out region 2 faces away from the coupling-in region 1, and the first side edge is provided with a light-returning region 3. In practical applications, the light beam with image information can propagate in the waveguide substrate 4 by total reflection, and when the light beam propagates to the edge of the coupling-out region 2, especially at the edge far from the coupling-in region 1, i.e. at the first side edge, the light beam is not completely coupled out due to the effect of the coupling-out region 2, and part of the light beam is not utilized, so as to further reduce the processing cost and the processing difficulty, for at least three side edges of the coupling-out region 2, the light return region 3 can be arranged only at the edge far from the coupling-in region 1, i.e. the light return region 3 can be arranged only at the first side edge.

In some embodiments, referring to fig. 4, the first side edge of the coupling-out area 2 has a second side edge and a third side edge which are adjacent to each other, and the second side edge and/or the third side edge is also provided with the light return area 3. In order to further improve the energy utilization rate, besides the light return region 3 is arranged at the edge far from the coupling-in region 1, the light return region 3 can be arranged at both the left side edge and the right side edge of the coupling-out region 2, the light return region 3 is in a semi-surrounding structure or a T-shaped structure, and in other embodiments, the light return region 3 can be arranged at only the left side edge or the right side edge of the coupling-out region 2 on the basis of the light return region 3 arranged at the edge far from the coupling-in region 1.

In some embodiments, referring to fig. 5 and fig. 6, the light returning area 3 may be disposed at the edge of the coupling-out area 2, and in other embodiments, referring to fig. 2 to fig. 4, a gap may exist between the light returning area 3 and the edge of the coupling-out area 2.

In some embodiments, the width of the light returning region 3 is D, the thickness of the waveguide substrate 4 is D, and the maximum total reflection angle of the light beam when propagating through the waveguide substrate 4 by total reflection is θ, the relationship between the three is: d > 2D tan θ.

In some embodiments, the surface of the light returning area 3 is provided with a coating layer, and the coating layer is made of a material with a high refractive index.

Referring to fig. 7 and 8, in some embodiments, the light returning area 3 is a two-dimensional cylinder structure, the diameter of the cylinder is 200nm, the height of the cylinder is 100nm, and a titanium dioxide film with a thickness of 80nm is coated on the cylinder. The grating period of the light return area 3 is consistent with that of the coupling-out area 2, and the grating direction of the light return area 3 is consistent with that of the coupling-out area 2.

In practical applications, the grating structure, size, period, and direction of the light returning area 3 can be set according to practical requirements, and need not be limited by the embodiments of the present invention.

In a second aspect, an embodiment of the present invention provides a near-eye display system, referring to fig. 1, including: the micro-projector 5 and the optical waveguide according to any of the above embodiments, please refer to the above embodiments for details of the optical waveguide, which are not described herein again, wherein an image source in the micro-projector 5 may be one of LCOS, DMD, OLED, and MEMS.

In the embodiment of the present invention, the light emitted from the micro-projector 5 is coupled into the waveguide substrate 4 through the coupling-in region 1, the light coupled into the waveguide substrate 4 is propagated through total reflection in the waveguide substrate 4, when the light is propagated to the coupling-out region 2, a part of the light is coupled out of the waveguide substrate 4 through the coupling-out region 2 and propagated to the human eye 6 for imaging, and another part of the light reaches the edge of the coupling-out region 2 and enters the light returning region 3, and the light returning region 3 makes the light entering the light returning region 3 propagate back to the coupling-out region 2 and is coupled out again to the human eye 6 under the action of the coupling-out region 2, so as to improve the energy utilization rate.

The optical waveguide and the near-eye display system provided in the embodiment of the present invention, wherein the optical waveguide includes a waveguide substrate, a coupling-in region, a coupling-out region, and a light return region: the light-in area, the light-out area and the light-returning area are arranged on the waveguide substrate, the light-in area is used for coupling in the light beam with the image information, the light-out area is used for coupling out the light beam with the image information, and the light-returning area is used for returning the light beam with the image information to the light-out area in a reverse direction; the coupling-out area comprises at least three side edges, the light return area is arranged on at least one side edge of the coupling-out area, and when the image light beams are transmitted to the edge of the coupling-out area, partial image light beams can reversely transmit back to the coupling-out area under the action of the light return area and then are coupled out to human eyes through the coupling-out area, so that the energy utilization rate of the two-dimensional expanded diffraction light waveguide is improved.

It should be noted that the above-described device embodiments are merely illustrative, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.