Diffraction optical waveguide and near-to-eye display equipment

Abstract

The utility model discloses a diffraction optical waveguide and a near-to-eye display device. The diffraction optical waveguide comprises a first waveguide sheet and a second waveguide sheet which are stacked. The first waveguide sheet comprises a first coupling-out structure, a first coupling-in structure and a second coupling-out structure which are sequentially arranged in the first direction, and pupil expansion in the first direction is achieved. The second waveguide sheet comprises a second coupling-in structure, a third coupling-in structure, a third coupling-out structure and a fourth coupling-out structure, the second coupling-in structure corresponds to the first coupling-out structure, the third coupling-in structure corresponds to the second coupling-out structure, and the second coupling-in structure and the third coupling-out structure are sequentially arranged in the second direction; the third coupling-in structure and the fourth coupling-out structure are sequentially arranged in a second direction to realize pupil expansion in the second direction, and the first direction is orthogonal to the second direction; wherein light enters the first waveguide sheet from the first coupling-in structure, and the third coupling-out structure and the fourth coupling-out structure correspond to the left eye and the right eye of a human eye respectively.

Description

Technical Field

[0001] This application relates to the field of augmented reality, and more particularly to a diffractive waveguide and a near-eye display device. Background Technology

[0002] Augmented reality is a technology that blends the real world with virtual information. Augmented reality display systems typically include micro-projectors and optical displays. The micro-projectors provide virtual display content for the augmented reality display system, which is then projected onto the viewer's eyes through the optical displays. The optical displays are usually transparent optical components, so that users can also see the real world through the optical displays at the same time.

[0003] To further improve user acceptance of near-eye display devices, sustainable wearability is a crucial factor. Lightweight design and conventional form factor are the development directions for improving sustainable wearability. There is an urgent need for a near-eye display device that is both lightweight and has a conventional form factor. Utility Model Content

[0004] This application provides a diffractive waveguide and a near-eye display device, wherein the diffractive waveguide realizes binocular display through an optomechanical system, which can achieve lightweight design; moreover, by using a double-layer waveguide, pupil expansion in different directions is realized on the two waveguide sheets respectively, which can achieve greater design freedom in conventional eyeglasses, especially in scenarios with a large field of view, the effect is particularly obvious.

[0005] This application provides a diffractive optical waveguide, comprising:

[0006] The device includes a first waveguide sheet and a second waveguide sheet stacked together. The first waveguide sheet includes a first coupling-out structure, a first coupling-in structure, and a second coupling-out structure arranged sequentially along a first direction to achieve pupil expansion in the first direction. The second waveguide sheet includes a second coupling-in structure, a third coupling-in structure, a third coupling-out structure, and a fourth coupling-out structure. The second coupling-in structure corresponds to the first coupling-out structure, and the third coupling-in structure corresponds to the second coupling-out structure. The second coupling-in structure and the third coupling-out structure are arranged sequentially in a second direction, and the third coupling-in structure and the fourth coupling-out structure are arranged sequentially in the second direction to achieve pupil expansion in the second direction. The first direction is orthogonal to the second direction. Light enters the first waveguide sheet from the first coupling-in structure, and the third coupling-out structure and the fourth coupling-out structure correspond to the left and right eyes of the human eye, respectively.

[0007] In practice, light enters the first waveguide from the first coupling structure and is simultaneously transmitted in two opposite directions to the first coupling structure and the second coupling structure, respectively. After being coupled out of the first waveguide from the first coupling structure and the second coupling structure, light is incident on the second coupling structure and the third coupling structure, respectively. Light coupled into the second waveguide from the second coupling structure is coupled out from the third coupling structure, and light coupled into the second waveguide from the third coupling structure is coupled out from the fourth coupling structure.

[0008] In practice, the first waveguide sheet has a size slightly larger than the first coupling structure in the second direction, and a size slightly larger than the second coupling structure in the second direction, so as to constrain light propagation in the first waveguide sheet along the first direction by means of reflection.

[0009] In practice, the first waveguide sheet is a strip waveguide sheet and includes four surfaces parallel to the first direction. The four surfaces include a first surface and a second surface that are parallel to each other, as well as a third surface and a fourth surface that are parallel to each other. The first coupling structure, the first coupling structure, and the second coupling structure are disposed on the first surface and / or the second surface. A reflective film layer is disposed on the outer surface of the third surface and / or the fourth surface.

[0010] In practice, light rays are incident obliquely onto the first coupling structure, and after interacting with the third and fourth surfaces an even number of times, the light rays are coupled out of the first waveguide sheet from the first coupling structure and then incident onto the second coupling structure; or, after interacting with the third and fourth surfaces an even number of times, the light rays are coupled out of the first waveguide sheet from the second coupling structure and then incident onto the third coupling structure.

[0011] In practice, the first coupling-out structure, the first coupling-in structure, the second coupling-out structure, the second coupling-in structure, the third coupling-in structure, the third coupling-out structure, and the fourth coupling-out structure are all one-dimensional grating structures.

[0012] Implementably, the first coupling-out structure and the second coupling-out structure are mirror-symmetric about the first coupling-in structure; the second coupling-in structure and the third coupling-in structure are mirror-symmetric about the first coupling-in structure; and the third coupling-out structure and the fourth coupling-out structure are mirror-symmetric about the first coupling-in structure.

[0013] Implementably, the second coupling-in structure is adjacent to the third coupling-out structure; the third coupling-in structure is adjacent to the fourth coupling-out structure.

[0014] In practice, the first waveguide sheet includes a first part and a second part, with a gap between the first part and the second part; the first part is provided with a first coupling structure, a first coupling structure and a second coupling structure, and the region of the second part corresponding to the third coupling structure and the fourth coupling structure has refractive power.

[0015] This application also provides a near-eye display device, which includes a diffractive waveguide and an optomechanic as described in any of the preceding claims.

[0016] This application provides a diffractive waveguide and a near-eye display device. The diffractive waveguide includes a first waveguide sheet and a second waveguide sheet stacked together. The first waveguide sheet includes a first coupling structure, a first coupling structure, and a second coupling structure arranged sequentially along a first direction to achieve pupil expansion in the first direction. The second waveguide sheet includes a second coupling structure, a third coupling structure, a third coupling structure, and a fourth coupling structure. The second coupling structure corresponds to the first coupling structure, and the third coupling structure corresponds to the second coupling structure. The second coupling structure and the third coupling structure are arranged sequentially in a second direction, and the third coupling structure and the fourth coupling structure are arranged sequentially in a second direction to achieve pupil expansion in the second direction. Thus, two-dimensional pupil expansion is achieved through the two waveguide sheets, providing greater design freedom in conventional eyeglasses, especially in scenarios with a large field of view. Moreover, light enters the first waveguide sheet from the first coupling structure, and the third and fourth coupling structures correspond to the left and right eyes of the human eye, respectively. Binocular display is achieved through a single-optical-engine, which helps to reduce product weight. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the split structure of a diffractive waveguide provided in an embodiment of this application;

[0019] Figure 2 A schematic diagram of a split structure of another diffractive waveguide provided in an embodiment of this application;

[0020] Figure 3 This is a schematic diagram of another diffractive waveguide structure provided in an embodiment of this application;

[0021] Attached image labels:

[0022] 100: First waveguide plate;

[0023] 101: First coupling-in structure; 102: First coupling-out structure; 103: Second coupling-out structure;

[0024] 110: Part One; 120: Part Two;

[0025] 200: Second waveguide plate;

[0026] 201: Second coupling-in structure; 202: Second coupling-in structure; 203: Third coupling-out structure; 204: Fourth coupling-out structure. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] The technical solution of this application will be described in detail below with reference to specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0029] This application provides a diffractive optical waveguide, which includes a first waveguide sheet and a second waveguide sheet stacked together. The first waveguide sheet includes a first coupling-out structure, a first coupling-in structure, and a second coupling-out structure arranged sequentially along a first direction to achieve pupil expansion in the first direction. The second waveguide sheet includes a second coupling-in structure, a third coupling-in structure, a third coupling-out structure, and a fourth coupling-out structure. The second coupling-in structure corresponds to the first coupling-out structure, and the third coupling-in structure corresponds to the second coupling-out structure. The second coupling-in structure and the third coupling-out structure are arranged sequentially in a second direction, and the third coupling-in structure and the fourth coupling-out structure are arranged sequentially in a second direction to achieve pupil expansion in the second direction. The first direction and the second direction are orthogonal. Light enters the first waveguide sheet from the first coupling-in structure, and the third coupling-out structure and the fourth coupling-out structure correspond to the left and right eyes of the human eye, respectively.

[0030] For example, refer to Figure 1The figure illustrates a schematic diagram of the diffractive waveguide in one embodiment. The upper part of the figure shows the first waveguide sheet 100, including a first coupling-out structure 102, a first coupling-in structure 101, and a second coupling-out structure 103 arranged sequentially along a first direction. The lower part of the figure shows the second waveguide sheet 200, including a second coupling-in structure 201, a third coupling-in structure 202, a third coupling-out structure 203, and a fourth coupling-out structure 204. The second coupling-in structure 201 corresponds to the first coupling-out structure 102, and the third coupling-in structure 202 corresponds to the second coupling-out structure 103. The second coupling-in structure 201 and the third coupling-out structure 203 are arranged sequentially along a second direction, and the third coupling-in structure 202 and the fourth coupling-out structure 204 are arranged sequentially along a second direction. The first waveguide sheet 100 and the second waveguide sheet 200 can be stacked parallel to each other or at a certain angle.

[0031] In practice, light enters the first waveguide from the first coupling structure and is simultaneously transmitted to the first coupling structure and the second coupling structure in two opposite directions. After being coupled out of the first waveguide from the first coupling structure and the second coupling structure, light is incident on the second coupling structure and the third coupling structure, respectively. Light coupled into the second waveguide from the second coupling structure is coupled out from the third coupling structure, and light coupled into the second waveguide from the third coupling structure is coupled out from the fourth coupling structure.

[0032] For example, light enters the first waveguide 100 from the first coupling structure 101. A portion of the light travels to the left to the first coupling structure 102, then exits through the first coupling structure 102 and is incident on the corresponding second coupling structure 201; another portion travels to the right to the second coupling structure 103, then exits through the second coupling structure 103 and is incident on the corresponding third coupling structure 202, thus achieving pupil expansion in the first direction. Light entering the second waveguide 200 from the second coupling structure 201 travels to the third coupling structure 203, then exits through the third coupling structure 203 and is incident on the human eye; light entering the second waveguide 200 from the third coupling structure 202 travels to the fourth coupling structure 204, then exits through the fourth coupling structure 204 and is incident on the human eye, thus achieving pupil expansion in the second direction. That is, the light emitted from the optical engine is the incident light of the first waveguide 100, the light emitted from the first waveguide 100 is the incident light of the second waveguide 200, and the light emitted from the second waveguide 200 is the imaging light. In this way, on the one hand, binocular display can be achieved with a single optical engine, which can reduce the weight of an optical engine-related component and help to make the product lighter; on the other hand, the pupil expansion in different directions can be achieved by using two layers of waveguides, which provides greater design freedom in conventional glasses form, especially in large field-of-view scenarios.

[0033] In some embodiments, the size of the second coupling region is larger than the size of the first coupling region in order to better receive light emitted from the first coupling region. The size of the third coupling region is larger than the size of the second coupling region in order to better receive light emitted from the second coupling region.

[0034] In practice, the size of the first waveguide sheet in the second direction is slightly larger than the size of the first coupling structure in the second direction, and slightly larger than the size of the second coupling structure in the second direction, so as to constrain the propagation of light in the first waveguide sheet in the first direction by means of reflection.

[0035] In practice, the first waveguide sheet is a strip waveguide sheet and includes four surfaces parallel to the first direction. The four surfaces include a first surface and a second surface that are parallel to each other, as well as a third surface and a fourth surface that are parallel to each other. A first coupling structure, a first coupling structure, and a second coupling structure are disposed on the first surface and / or the second surface. A reflective film layer is disposed on the outer surface of the third surface and / or the fourth surface.

[0036] For example, the first waveguide sheet is a square strip waveguide. Along the first direction, the four faces of the square strip waveguide are: a first surface and a second surface that are parallel to each other, and a third surface and a fourth surface that are parallel to each other. All four surfaces are working surfaces. The first and second surfaces constrain the light rays to propagate along the first direction by total internal reflection, while the third and fourth surfaces reflect the light rays.

[0037] In practice, light rays are obliquely incident on the first coupling structure, and after interacting with the third and fourth surfaces an even number of times, the light rays are coupled out of the first waveguide sheet from the first coupling structure and then incident on the second coupling structure; or, after interacting with the third and fourth surfaces an even number of times, the light rays are coupled out of the first waveguide sheet from the second coupling structure and then incident on the third coupling structure.

[0038] It is understandable that when light undergoes an even number of reflections on the third and fourth surfaces and then interacts with the first / second coupling structure to be coupled out, the image of the emitted light is completely consistent with the image of the light emitted by the optomechanical system. However, when light undergoes an odd number of reflections on the third and fourth surfaces and then interacts with the first / second coupling structure, the image of the emitted light is a mirror image of the image of the light emitted by the optomechanical system. To avoid the problem of two contradictory image displays, it is necessary to effectively prevent the mirrored light from being coupled out of the first waveguide. In this application, the light is designed to be incident obliquely onto the first coupling structure. By coordinating the period and direction of the coupling and coupling structures, the light is controlled to interact with the third and fourth surfaces an even number of times before being coupled out of the first waveguide from the first coupling structure and then incident onto the second coupling structure. Alternatively, the light may interact with the third and fourth surfaces an even number of times before being coupled out of the first waveguide from the second coupling structure and then incident onto the third coupling structure, thereby ensuring that the direction of the light coupled out of the first waveguide is consistent.

[0039] In this application, each coupling-in structure and coupling-out structure can be a diffractive optical structure or a geometric optical structure.

[0040] In practice, the first output structure, the first input structure, the second output structure, the second input structure, the third input structure, the third output structure, and the fourth output structure are all one-dimensional grating structures.

[0041] In practice, the first and second coupling-out structures are mirror-symmetric about the first coupling-in structure; the second and third coupling-in structures are mirror-symmetric about the first coupling-in structure; and the third and fourth coupling-out structures are mirror-symmetric about the first coupling-in structure.

[0042] For example, refer to Figure 1 As can be seen, the first coupling-out structure 102 and the second coupling-out structure 103 are mirror-symmetric about the first coupling-in structure 101; the second coupling-in structure 201 and the third coupling-in structure 202 are mirror-symmetric about the first coupling-in structure 101; and the third coupling-out structure 203 and the fourth coupling-out structure 204 are mirror-symmetric about the first coupling-in structure.

[0043] In practice, the second coupling-in structure is adjacent to the third coupling-out structure; the third coupling-in structure is adjacent to the fourth coupling-out structure.

[0044] Specifically, in some embodiments, the coupling-in structure and coupling-out structure corresponding to a single eye on the second waveguide sheet can be simultaneously implemented using the same large-area grating structure. For example, refer to... Figure 2 The second coupling-in structure 201 and the third coupling-out structure 203 are implemented as the same grating structure; the third coupling-in structure 202 and the fourth coupling-out structure 204 are implemented as the same grating structure.

[0045] In practice, the first waveguide sheet includes a first part and a second part, with a gap between the first part and the second part; the first part is provided with a first coupling structure, a first coupling structure and a second coupling structure, and the regions of the second part corresponding to the third coupling structure and the fourth coupling structure have refractive power.

[0046] For details, please refer to Figure 2 and Figure 3 The first waveguide 100 includes a first portion 110 and a second portion 120, with a gap between the first portion 110 and the second portion 120. This gap can be an air gap or a dielectric gap. (Reference) Figure 3 As can be seen, the area corresponding to the second part 120 and the third and fourth coupling structures has refractive power. In this way, the light from the virtual image (red) and the light from the external environment (blue) both enter the human eye after passing through the part with refractive power, which can perform image correction and is suitable for users with refractive errors. The refractive power of the second part can be customized or adaptively adjusted.

[0047] This application also provides a near-eye display device, which includes a diffractive waveguide and an optomechanic as described in any of the foregoing embodiments.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A diffractive optical waveguide, characterized by, The diffractive waveguide includes: A first waveguide sheet and a second waveguide sheet are stacked. The first waveguide sheet includes a first coupling-out structure, a first coupling-in structure, and a second coupling-out structure arranged sequentially along a first direction to achieve pupil expansion in the first direction. The second waveguide sheet includes a second coupling-in structure, a third coupling-in structure, a third coupling-out structure, and a fourth coupling-out structure. The second coupling-in structure corresponds to the first coupling-out structure, and the third coupling-in structure corresponds to the second coupling-out structure. The second coupling-in structure and the third coupling-out structure are arranged sequentially in a second direction, and the third coupling-in structure and the fourth coupling-out structure are arranged sequentially in the second direction to achieve pupil expansion in the second direction. The first direction and the second direction are orthogonal. Light enters the first waveguide sheet from the first coupling-in structure, and the third coupling-out structure and the fourth coupling-out structure correspond to the left and right eyes of the human eye, respectively.

2. The diffractive optical waveguide of claim 1, wherein, Light enters the first waveguide from the first coupling structure and is simultaneously transmitted in two opposite directions to the first coupling structure and the second coupling structure, respectively. After being coupled out of the first waveguide from the first coupling structure and the second coupling structure, light is incident on the second coupling structure and the third coupling structure, respectively. Light coupled into the second waveguide from the second coupling structure is coupled out from the third coupling structure, and light coupled into the second waveguide from the third coupling structure is coupled out from the fourth coupling structure.

3. The diffractive optical waveguide of claim 1, wherein, The first waveguide sheet has a size slightly larger than the first coupling structure in the second direction, and also slightly larger than the second coupling structure in the second direction, so as to constrain light propagation in the first waveguide sheet along the first direction by means of reflection.

4. The diffractive optical waveguide of claim 3, wherein, The first waveguide sheet is a strip-shaped waveguide sheet and includes four surfaces parallel to the first direction. The four surfaces include a first surface and a second surface that are parallel to each other, as well as a third surface and a fourth surface that are parallel to each other. The first coupling structure, the first coupling structure, and the second coupling structure are disposed on the first surface and / or the second surface. A reflective film layer is disposed on the outer surface of the third surface and / or the fourth surface.

5. The diffractive optical waveguide of claim 4, wherein, Light rays are incident obliquely on the first coupling structure, and after interacting with the third and fourth surfaces an even number of times, the light rays are coupled out of the first waveguide sheet from the first coupling structure and then incident on the second coupling structure; or, after interacting with the third and fourth surfaces an even number of times, the light rays are coupled out of the first waveguide sheet from the second coupling structure and then incident on the third coupling structure.

6. The diffractive optical waveguide of claim 1, wherein, The first coupling-out structure, the first coupling-in structure, the second coupling-out structure, the second coupling-in structure, the third coupling-in structure, the third coupling-out structure, and the fourth coupling-out structure are all one-dimensional grating structures.

7. The diffractive optical waveguide of claim 1, wherein, The first coupling-out structure and the second coupling-out structure are mirror-symmetric about the first coupling-in structure; the second coupling-in structure and the third coupling-in structure are mirror-symmetric about the first coupling-in structure; the third coupling-out structure and the fourth coupling-out structure are mirror-symmetric about the first coupling-in structure.

8. The diffractive optical waveguide of claim 1, wherein, The second coupling-in structure is adjacent to the third coupling-out structure; the third coupling-in structure is adjacent to the fourth coupling-out structure.

9. The diffractive optical waveguide of claim 1, wherein, The first waveguide sheet includes a first part and a second part, with a gap between the first part and the second part; the first part is provided with a first coupling structure, a first coupling structure and a second coupling structure, and the area of ​​the second part corresponding to the third coupling structure and the fourth coupling structure has refractive power.

10. A near-eye display device, comprising: The near-eye display device includes a diffractive waveguide and an optomechanic as described in any one of claims 1-9.

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