Diffractive optical waveguide apparatus, ar display system, and design method for in-coupling grating

Abstract

A diffractive optical waveguide apparatus (100), comprising an optical engine (10), a polarization beam-splitting assembly (20) and a waveguide (30), wherein the optical engine (10) is configured to emit unpolarized light (L); the waveguide (30) comprises in-coupling gratings (31), which comprise a first in-coupling grating (311) and a second in-coupling grating (312); the polarization beam-splitting assembly (20) is arranged downstream of an optical path of the optical engine (10), and is arranged upstream of optical paths of the in-coupling gratings (31); the polarization beam-splitting assembly (20) is configured to modulate the unpolarized light (L) emitted by the optical engine (10) into first polarized light (L1) and second polarized light (L2), and is configured to couple the first polarized light (L1) into the first in-coupling grating (311) and couple the second polarized light (L2) into the second in-coupling grating (312); the optical engine (10), the polarization beam-splitting assembly (20) and the first in-coupling grating (311) form a first optical path for the first polarized light (L1); and the optical engine (10), the polarization beam-splitting assembly (20) and the second in-coupling grating (312) form a second optical path for the second polarized light (L2), the polarization states of the first polarized light (L1) and the second polarized light (L2) being identical or different, and the first polarized light (L1) and the second polarized light (L2) each being either S-polarized light or P-polarized light. The diffractive optical waveguide apparatus (100) can realize optical path outputs with identical polarization states by means of different optical paths, and can also realize optical path outputs with different polarization states by means of different optical paths, thereby achieving enhanced performance.

Description

Diffraction optical waveguide device, AR display system, and design method of coupling grating Technical Field

[0001] The present disclosure generally relates to the field of optics, and more particularly to a design method for a diffractive optical waveguide device, an AR display system, and an in-coupling grating. Background Art

[0002] With the advancement of science and technology, augmented reality (AR), a highly intelligent and portable display technology, is gradually becoming accessible to the public. Its key feature is the overlaying of virtual images onto real scenes, allowing users to simultaneously view the virtual images and the real scene. These characteristics have led to the technology's increasing application in industries such as security, education, healthcare, military, industry, and entertainment.

[0003] Diffractive waveguides are commonly used in AR display systems, but some current diffractive waveguides offer suboptimal performance. For example, they cannot achieve dual-path output for incident light with the same polarization state, cannot achieve split-path output for incident light with different polarization states, require internal polarization separation of the incident light, or require multiple optical engines. These devices are often too small to be miniaturized, hindering overall device miniaturization and resulting in high power consumption. Therefore, optimizing the structure of diffractive waveguides to achieve superior performance remains a key technical challenge in this field.

[0004] The contents of the background technology section are merely the technologies known to the inventors and do not necessarily represent the existing technologies in this field. Summary of the Invention

[0005] In response to one or more problems existing in the prior art, the present disclosure provides a diffraction optical waveguide device that can achieve optical path output of the same polarization state through different optical paths, and can also achieve optical path output of different polarization states through different optical paths, with better performance.

[0006] The diffraction light waveguide device includes an optical machine, a polarization beam splitting component and a waveguide:

[0007] wherein the optical engine is configured to emit non-polarized light;

[0008] The waveguide includes an incoupling grating, and the incoupling grating includes a first incoupling grating and a second incoupling grating;

[0009] The polarization splitting component is arranged downstream of the optical path of the optical machine and upstream of the optical path of the coupling grating; the polarization splitting component is configured to modulate the non-polarized light emitted by the optical machine into a first polarized light and a second polarized light; and is configured to couple the first polarized light into the first coupling grating, and couple the second polarized light into the second coupling grating;

[0010] The optical engine, the polarization beam splitting component and the first coupling-in grating form a first optical path for the first polarized light;

[0011] The optical engine, the polarization beam splitting component and the second coupling-in grating form a second optical path for the second polarized light;

[0012] Wherein, the polarization states of the first polarized light and the second polarized light are the same or different;

[0013] The first polarized light and the second polarized light are either S polarized light or P polarized light respectively.

[0014] Optionally, the first polarized light and the second polarized light are both P-polarized light; or the first polarized light and the second polarized light are both S-polarized light.

[0015] Optionally, the polarization splitting component includes an optical path deflector, a polarization beam splitter and a polarization rotator, wherein

[0016] The optical path deflector is configured to deflect the non-polarized light incident thereon;

[0017] The polarization beam splitter is configured to perform polarization separation on the unpolarized light incident thereon;

[0018] The polarization rotator is configured to rotate the polarization state of polarized light incident thereon.

[0019] Optionally, the optical path deflector includes a prism; the polarization beam splitter includes a beam splitting surface embedded in the prism;

[0020] The beam splitting surface is configured to reflect or transmit a portion of the non-polarized light incident thereon to form S-polarized light, and is configured to transmit or reflect another portion of the non-polarized light incident thereon to form P-polarized light;

[0021] The polarization rotator is configured to modulate the S-polarized light into P-polarized light; or modulate the P-polarized light into S-polarized light.

[0022] Optionally, the polarizer is arranged outside the prism and downstream of the optical path of the S-polarized light; the P-polarized light modulated by the polarizer is the first polarized light, and the P-polarized light transmitted through the splitting surface is the second polarized light.

[0023] Optionally, the polarizer is arranged outside the prism and downstream of the optical path of the P-polarized light, the S-polarized light reflected by the splitting surface is totally reflected on the surface of the prism and then emitted as the first polarized light, and the S-polarized light modulated by the polarizer is the second polarized light; the directions of the first polarized light and the second polarized light are parallel to the direction of the unpolarized light.

[0024] Optionally, the polarizer is arranged inside the prism and downstream of the optical path of the P-polarized light; the S-polarized light reflected by the splitting surface is the first polarized light; the S-polarized light modulated by the polarizer and then emitted after total reflection on the surface of the prism is the second polarized light; the directions of the first polarized light and the second polarized light are perpendicular to the direction of the unpolarized light.

[0025] Optionally, the deflector includes a half-wave plate, and the half-wave plate is attached to the surface of the prism.

[0026] Optionally, the first polarized light is S-polarized light, and the second polarized light is P-polarized light.

[0027] Optionally, the polarization splitting component includes an optical path deflector and a polarization beam splitter; the optical path deflector includes a prism; the polarization beam splitter includes a splitting surface embedded in the prism; the splitting surface is configured to reflect or transmit a portion of the non-polarized light incident thereon to form S-polarized light, and is configured to transmit or reflect another portion of the non-polarized light incident thereon to form P-polarized light.

[0028] Optionally, the S-polarized light reflected by the beam splitting surface and then emitted after total reflection on the surface of the prism is the first polarized light; and the P-polarized light transmitted through the beam splitting surface is the second polarized light.

[0029] Optionally, the first coupling grating and the second coupling grating are arranged side by side on the same side of the waveguide; and grating parameters of the first coupling grating and the second coupling grating are respectively determined by optical parameters of the first polarized light and the second polarized light incident thereon.

[0030] Optionally, the optical parameters include one or more of diffraction angle, polarization state, comprehensive coupling efficiency and non-uniformity.

[0031] Optionally, the grating parameters include one or more of grating type, grating period, grating tilt angle, duty cycle and grating depth; wherein the grating type includes any one of a transmissive rectangular grating, a transmissive slanted grating and a reflective blazed grating.

[0032] Optionally, the polarization states of the first polarized light and the second polarized light are the same, and at least some of the grating parameters of the first coupling grating and the second coupling grating are the same; or the polarization states of the first polarized light and the second polarized light are different, and at least some of the grating parameters of the first coupling grating and the second coupling grating are different.

[0033] Optionally, the waveguide further includes a decoupling grating, which is disposed on the waveguide, and the decoupling grating is configured to couple the first polarized light propagating in the waveguide into the waveguide via the first coupling-in grating and couple the second polarized light propagating in the waveguide out of the waveguide; and couple the second polarized light propagating in the waveguide into the waveguide via the second coupling-in grating and couple the second polarized light propagating in the waveguide out of the waveguide.

[0034] Optionally, a turning grating is further included, wherein the turning grating is arranged on the waveguide and is located in the optical path between the coupling-in grating and the coupling-out grating; the turning grating is configured to deflect and / or expand the pupil of the first polarized light incident on the turning grating via the first coupling-in grating; and / or the turning grating is configured to deflect and / or expand the pupil of the second polarized light incident on the turning grating via the second coupling-in grating.

[0035] Optionally, along the optical path direction of the first polarized light and the second polarized light, the size of the turning grating increases.

[0036] Optionally, the optical engine includes a light source, and the light source includes any one or more of LCOS, DLP and MicroLED.

[0037] The present disclosure also provides another diffraction light waveguide device, comprising an optical engine, a polarization beam splitting component, and a waveguide;

[0038] wherein the optical engine is configured to emit a first non-polarized light;

[0039] The waveguide includes an incoupling grating, and the incoupling grating includes a first incoupling grating and a second incoupling grating;

[0040] The polarization splitting component is arranged downstream of the optical path of the optical machine and upstream of the optical path of the coupling grating; the polarization splitting component is configured to modulate the first non-polarized light emitted by the optical machine into a first polarized light and a second non-polarized light; and is configured to couple the first polarized light into the first coupling grating, and couple the second non-polarized light into the second coupling grating;

[0041] The optical engine, the polarization beam splitting component and the first coupling-in grating form a first optical path for the first polarized light;

[0042] The optical engine, the polarization beam splitting component and the second coupling-in grating form a second optical path for the second unpolarized light;

[0043] Wherein, the first polarized light is any one of S polarized light and P polarized light.

[0044] Optionally, the polarization splitting component includes an optical path deflector and a polarization beam splitter; the optical path deflector includes a prism; the polarization beam splitter includes a splitting surface embedded in the prism; the splitting surface is configured to reflect or transmit a portion of the first non-polarized light incident thereon to form S-polarized light, and the S-polarized light is the first polarized light, and is configured to transmit or reflect another portion of the first non-polarized light incident thereon to form P-polarized light, and the P-polarized light is modulated by the prism surface to form the second non-polarized light.

[0045] The present disclosure also provides an AR display system, comprising a diffraction light waveguide device as described above; and / or another diffraction light waveguide device as described above.

[0046] Optionally, the AR display system includes any one of a one-dimensional single-lens monocular display system, a one-dimensional single-lens binocular display system, and a two-dimensional single-lens binocular system.

[0047] The present disclosure also provides a method for designing an incoupling grating, comprising:

[0048] Based on different incident lights, parameter scanning is performed on the coupling grating to obtain output characteristic curves that vary with diffraction angles for the different incident lights;

[0049] Determining, based on the output characteristic curves for different incident lights, optimized values ​​of the output characteristics for different incident lights and optimized values ​​of the grating parameters corresponding to the optimized values ​​of the output characteristics; and

[0050] Designing the first coupling grating and / or the second coupling grating as described above according to the optimized values ​​of the grating parameters;

[0051] The different incident lights include unpolarized light, S-polarized light and P-polarized light.

[0052] Optionally, the grating parameters of the coupled-in grating include one or more of grating type, grating period, grating tilt angle, duty cycle and grating depth; the grating type includes any one of a transmissive rectangular grating, a transmissive slanted grating and a reflective blazed grating.

[0053] Optionally, the output characteristics include comprehensive coupling efficiency and non-uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the present disclosure and do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0055] FIG. 1 a shows a schematic diagram of a diffractive light waveguide device according to some embodiments of the present disclosure.

[0056] FIG1 b shows a schematic diagram of S-polarized light according to some embodiments of the present disclosure.

[0057] FIG. 1 c shows a schematic diagram of P-polarized light according to some embodiments of the present disclosure.

[0058] FIG2 shows a schematic diagram of a diffractive optical waveguide device according to some preferred embodiments of the present disclosure.

[0059] FIG3 shows a schematic diagram of a diffraction optical waveguide device according to some other preferred embodiments of the present disclosure.

[0060] FIG4 shows a schematic diagram of a diffraction light waveguide device according to some other preferred embodiments of the present disclosure.

[0061] FIG5 shows a schematic diagram of a diffraction light waveguide device according to some other preferred embodiments of the present disclosure.

[0062] FIG6 shows a schematic diagram of a diffractive light waveguide device according to some embodiments of the present disclosure.

[0063] FIG7 shows a schematic diagram of a transmissive rectangular grating according to some embodiments of the present disclosure.

[0064] FIG8 shows a schematic diagram of a transmissive slanted grating according to some embodiments of the present disclosure.

[0065] FIG9 shows a schematic diagram of an AR display system according to some embodiments of the present disclosure.

[0066] FIG10 shows a schematic diagram of an AR display system according to some other embodiments of the present disclosure.

[0067] FIG11 shows a schematic diagram of an AR display system according to some other embodiments of the present disclosure.

[0068] FIG12 shows a flow chart of a method for designing an incoupling grating according to some embodiments of the present disclosure.

[0069] 13a to 13c are schematic diagrams showing output characteristic curves varying with diffraction angles obtained by performing parameter scanning on the coupling grating based on different incident lights according to some embodiments of the present disclosure.

[0070] 14a to 14f are schematic diagrams showing output characteristic curves varying with diffraction angles obtained by performing parameter scanning on the coupling-in grating based on different incident lights according to other embodiments of the present disclosure.

[0071] 15a to 15f are schematic diagrams showing output characteristic curves varying with diffraction angles obtained by performing parameter scanning on the coupling-in grating based on different incident lights according to some other embodiments of the present disclosure.

[0072] FIG16 is a schematic diagram showing light incident on a waveguide and transmitted through an in-coupling grating according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0073] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present disclosure. Therefore, the drawings and description are to be considered as illustrative in nature and not restrictive.

[0074] In the description of the present disclosure, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," "clockwise," "counterclockwise," and the like, indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely for the purpose of facilitating the description of the present disclosure and simplifying the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present disclosure. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of the described features. In the description of the present disclosure, "plurality" means two or more, unless otherwise expressly and specifically defined.

[0075] In the description of this disclosure, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood broadly. For example, they can refer to fixed, removable, or integral connections; mechanical, electrical, or intercommunication connections; direct or indirect connections through an intermediary; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this disclosure based on specific circumstances.

[0076] In this disclosure, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact via another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or diagonally above the second feature, or may simply mean that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or diagonally below the second feature, or may simply mean that the first feature is at a lower level than the second feature.

[0077] The disclosure below provides many different embodiments or examples for realizing different structures of the present disclosure. In order to simplify the disclosure of the present disclosure, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present disclosure. In addition, the present disclosure may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present disclosure provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0078] The preferred embodiments of the present disclosure are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0079] The present disclosure provides a diffraction light waveguide device. Figure 1a shows a schematic diagram of a diffraction light waveguide device 100 according to some embodiments of the present disclosure. As shown in Figure 1a, the diffraction light waveguide device 100 includes an optical engine 10, a polarization splitting component 20 and a waveguide 30. The optical engine 10 is configured to emit non-polarized light L. The waveguide 30 includes a coupled-in grating 31, and the coupled-in grating 31 includes a first coupled-in grating 311 and a second coupled-in grating 312. The polarization splitting component 20 is arranged downstream of the optical path of the optical engine 10 and upstream of the optical path of the coupled-in grating 31. The polarization splitting component 20 is configured to modulate the non-polarized light L emitted by the optical engine 10 into a first polarized light L1 and a second polarized light L2; and is configured to couple the first polarized light L1 into the first coupled-in grating 311 and couple the second polarized light L2 into the second coupled-in grating 312. The optical engine 10, the polarization splitter component 20 and the first coupling-in grating 311 form a first optical path for the first polarized light L1. The optical engine 10, the polarization splitter component 20 and the second coupling-in grating 312 form a second optical path for the second polarized light L2. The polarization states of the first polarized light L1 and the second polarized light L2 are the same or different. The first polarized light L1 and the second polarized light L2 are respectively any one of S polarized light and P polarized light. In other words, the first polarized light L1 and the second polarized light L2 can both be P polarized light. The first polarized light L1 and the second polarized light L2 can also both be S polarized light. Alternatively, one of the first polarized light L1 and the second polarized light L2 is P polarized light and the other is S polarized light. The diffraction light waveguide device disclosed in the present invention, through the synergistic effect of the optical engine, the polarization splitter component and the waveguide, can achieve optical path output of the same polarization state through different optical paths, and can also achieve optical path output of different polarization states through different optical paths, and has better performance. In other words, the diffraction optical waveguide device disclosed in the present invention can achieve dual-path output of S-polarized light, dual-path output of P-polarized light, and split-path output of S-polarized light and P-polarized light through different optical paths.

[0080] An unpolarized light beam can be decomposed into S-polarized light and P-polarized light. As shown in Figure 1b, when the polarization direction of the incident light beam is perpendicular to the paper surface (parallel to the direction of the grid lines), the incident light beam is S-polarized light (TE wave or S wave). As shown in Figure 1c, when the polarization direction of the incident light beam is parallel to the paper surface (perpendicular to the direction of the grid lines), the incident light beam is P-polarized light (TM wave or P wave).

[0081] As shown in FIG1 a , the optical engine 10 includes a light source 101 , which can emit unpolarized light L. In some embodiments, the light source 101 can include any one or more of LCOS, DLP, and MicroLED.

[0082] In some embodiments, the polarization beam splitting assembly 20 may include an optical path deflector, a polarization beam splitter, and a polarization rotator. The optical path deflector is configured to deflect non-polarized light incident thereon. The polarization beam splitter is configured to perform polarization separation on the non-polarized light incident thereon. The polarization rotator is configured to rotate the polarization state of polarized light incident thereon.

[0083] Some specific structures of the diffraction optical waveguide device disclosed in the present invention are introduced below.

[0084] FIG2 shows a schematic diagram of a diffraction light waveguide device 200 according to some preferred embodiments of the present disclosure. As shown in FIG2 , the diffraction light waveguide device 200 includes an optical engine 10, a polarization beam splitter component 20, and a waveguide 30. The polarization beam splitter component 20 includes an optical path deflector 21, a polarization beam splitter 22, and a polarizer 23. The optical path deflector 21 can be a prism, for example, the parallelogram prism 211 and the right-angled triangle prism 212 shown in the figure. The polarization beam splitter 22 can be a beam splitter surface (beam splitter film) embedded in the prism. The beam splitter surface is configured to reflect or transmit (reflection is shown in the figure) a portion of the non-polarized light L incident thereon to form S-polarized light, and is configured to transmit or reflect (transmission is shown in the figure) another portion of the non-polarized light L incident thereon to form P-polarized light. The optical path deflector 21 and the polarization beam splitter 22 can be combined to form a polarization beam splitter prism (PBS). Specifically, the optical path deflector 21 can adopt a parallelogram prism 211 and a right-angled triangular prism 212, and the relative inclined surfaces of the parallelogram prism 211 and the right-angled triangular prism 212 can be attached or coated with a spectroscopic film and then glued together to form a PBS. The polarizer 23 can be arranged outside the prism and downstream of the optical path of the S-polarized light. As shown in Figure 2, the polarizer 23 can adopt a half-wave plate (half-wave plate), and the half-wave plate can be attached to the surface of the prism 21, that is, it can be attached to the light-emitting surface e1 of the parallelogram prism 211. In addition, the polarizer 23 can also adopt a similar device such as a metasurface polarizer that can realize polarization state rotation. The polarizer 23 is configured to modulate S-polarized light into P-polarized light. As shown in Figure 2, after the S-polarized light reflected by the beam splitter is totally reflected on surface e3 of the parallelogram prism 211, it is modulated by the polarizer 23 to form the P-polarized light L1, which is the first polarized light. The P-polarized light transmitted by the beam splitter is then emitted from the light-emitting surface e2 of the prism 212 to form the second polarized light L2. In other words, both the first polarized light L1 and the second polarized light L2 are P-polarized. The directions of the first polarized light L1 and the second polarized light L2 can be parallel to the direction of the unpolarized light L. Using the diffractive optical waveguide device 200, dual P-polarized light paths can be output via different optical paths.

[0085] FIG3 shows a schematic diagram of a diffraction light waveguide device 300 according to other preferred embodiments of the present disclosure. The structure of the diffraction light waveguide device 300 is substantially the same as that of the diffraction light waveguide device 200. The difference between the two is that, as shown in FIG3 , in the diffraction light waveguide device 300, the polarizer 23 can be disposed downstream of the optical path of the P-polarized light. In other words, the polarizer 23 can be attached to the light-emitting surface e2 of the right-angled triangular prism 212. The polarizer 23 is configured to modulate the P-polarized light into S-polarized light. The S-polarized light modulated by the polarizer 23 is the second polarized light L2. The S-polarized light reflected by the beam splitting surface is totally reflected on the surface of the prism 211, and the S-polarized light emitted is the first polarized light L1. In other words, the first polarized light L1 and the second polarized light L2 are both S-polarized light. The directions of the first polarized light L1 and the second polarized light L2 can be parallel to the direction of the unpolarized light L. The diffraction light waveguide device 300 can output two paths of S-polarized light through different optical paths.

[0086] In other embodiments, the polarization beam splitting assembly 20 may include an optical path deflector and a polarization beam splitter, but not a polarization rotator. The optical path deflector is configured to deflect unpolarized light incident thereon. The polarization beam splitter is configured to polarize and separate unpolarized light incident thereon. These are described in detail below.

[0087] FIG4 shows a schematic diagram of a diffraction light waveguide device 400 according to some other preferred embodiments of the present disclosure. As shown in FIG4 , in the diffraction light waveguide device 400, the polarizer 23 can be arranged inside the prism 21 and downstream of the optical path of the P-polarized light. The S-polarized light reflected by the beam splitter surface and emitted from the prism 211 is the first polarized light L1. The S-polarized light modulated by the polarizer 23 is totally reflected on the surface e4 of the prism 212 and then emitted as the S-polarized light is the second polarized light L2. In other words, the first polarized light L1 and the second polarized light L2 are both S-polarized light. The directions of the first polarized light L1 and the second polarized light L2 can be perpendicular to the direction of the unpolarized light L. Through the diffraction light waveguide device 400, dual-path S-polarized light can also be output through different optical paths.

[0088] FIG5 shows a schematic diagram of a diffraction light waveguide device 500 according to some other preferred embodiments of the present disclosure. As shown in FIG5 , the diffraction light waveguide device 500 includes an optical engine 10, a polarization beam splitting component 20, and a waveguide 30. The polarization beam splitting component 20 includes an optical path deflector 21 and a polarization beam splitter 22. The optical path deflector 21 can be a prism, for example, the parallelogram prism 211 and the right-angled triangular prism 212 shown in the figure. The polarization beam splitter 22 includes a beam splitting surface embedded in the prism. The beam splitting surface is configured to reflect or transmit (reflection is shown in the figure) a portion of the non-polarized light L incident thereon to form S-polarized light, and is configured to transmit or reflect (transmission is shown in the figure) another portion of the non-polarized light L incident thereon to form P-polarized light. The S-polarized light reflected by the beam splitting surface 22 is totally reflected on the surface of the prism 211, and the S-polarized light emitted is the first polarized light L1. The P-polarized light transmitted through the beam splitter 22 and then emitted from the prism 212 is the second polarized light L2. In other words, the first polarized light L1 is S-polarized light, and the second polarized light L2 is P-polarized light. The directions of the first polarized light L1 and the second polarized light L2 can be parallel to the direction of the unpolarized light L. The diffractive optical waveguide device 500 can output a single path of S-polarized light and a single path of P-polarized light via different optical paths.

[0089] The embodiments of Figures 1a to 5 introduce the diffraction light waveguide devices 100 to 500 of some embodiments of the present disclosure. The diffraction light waveguide devices 100 to 500 can achieve dual-path S-polarized light output through different optical paths, or achieve dual-path P-polarized light output through different optical paths, or achieve split-path output of S-polarized light and P-polarized light through different optical paths.

[0090] The present disclosure also provides a diffraction light waveguide device 600. FIG6 shows a schematic diagram of a diffraction light waveguide device 600 according to some embodiments of the present disclosure. As shown in FIG6 , the diffraction light waveguide device 600 includes an optical engine 10, a polarization splitter component 20, and a waveguide 30. The optical engine 10 is configured to emit a first non-polarized light Light1. The waveguide 30 includes a coupling grating 31, and the coupling grating 31 includes a first coupling grating 311 and a second coupling grating 312. The polarization splitter component 20 is arranged downstream of the optical path of the optical engine 10 and upstream of the optical path of the coupling grating 31. The polarization splitter component 20 is configured to modulate the first non-polarized light Light1 emitted by the optical engine 10 into a first polarized light L1 and a second non-polarized light Light2; and is configured to couple the first polarized light Light1 into the first coupling grating 311, and couple the second non-polarized light Light2 into the second coupling grating 312. The optical engine 10, the polarization splitting component 20 and the first coupling grating 311 form a first optical path for the first polarized light Light1. The optical engine 10, the polarization splitting component 20 and the second coupling grating 312 form a second optical path for the second non-polarized light Light2. The first polarized light L1 is any one of S-polarized light and P-polarized light. The polarization splitting component 20 includes an optical path deflector 21 and a polarization beam splitter 22. The optical path deflector 21 includes a prism, and the prism can be a parallelogram prism 211 and a right-angle triangle prism 212. The polarization beam splitter 22 includes a splitting surface embedded in the prism. The splitter surface is configured to reflect or transmit a portion of the first non-polarized light Light1 incident thereon to form S-polarized light (reflection is shown in the figure), and the light emitted by the S-polarized light after passing through the prism 211 is the first polarized light L1, and is configured to transmit or reflect another portion of the first non-polarized light Light1 incident thereon (transmission is shown in the figure) to form P-polarized light, and the P-polarized light is modulated by the surface e4 of the prism 212 and depolarized to form the second non-polarized light Light2. In other words, in this embodiment, the first polarized light L1 is S-polarized light, and the second non-polarized light Light2 is a mixture of S-polarized light and P-polarized light. It should be noted that, although not shown in the figure, the first polarized light L1 can also be P-polarized light. In actual applications, the setting method of the splitter surface can be flexibly set according to actual conditions.

[0091] In some embodiments, the light-emitting surface of the optical path deflector 21 can be coated with an anti-reflection film. As shown in FIG2 , the light-emitting surface e1 of the parallelogram prism 211 and the light-emitting surface e2 of the right-angled triangular prism 212 can be coated with an anti-reflection film, respectively. This can increase light transmittance, reduce light reflectivity, reduce light loss, reduce optical crosstalk, improve light utilization, and enhance optical path quality. It is understood that in the embodiments of FIG3 to FIG6 , the light-emitting surface of the optical path deflector 21 can be coated with an anti-reflection film, which will not be further described here.

[0092] 1a to 6 , the first coupling grating 311 and the second coupling grating 312 can be arranged side by side on the same side of the waveguide 30. The grating parameters of the first coupling grating 311 and the second coupling grating 312 can be determined by the optical parameters of the first polarized light L1 and the second polarized light L2 incident thereon, respectively.

[0093] The grating parameters include one or more of a grating type, a grating period, a grating inclination angle, a duty cycle, and a grating depth. The grating type includes any one of a transmission rectangular grating, a transmission helical grating, and a reflective blazed grating.

[0094] The optical parameters include one or more of a diffraction angle, a polarization state, a comprehensive coupling efficiency, and non-uniformity.

[0095] In some embodiments, the polarization states of the first polarized light L1 and the second polarized light L2 are the same, and at least some grating parameters of the first coupling-in grating 311 and the second coupling-in grating 312 are the same.

[0096] For example, referring to the diffraction optical waveguide device 200 shown in FIG2 , the polarization states of the first polarized light L1 and the second polarized light L2 are the same, both being P-polarized light. The grating type of the first coupling grating 311 and the second coupling grating 312 can both be transmissive rectangular gratings. As exemplarily shown in FIG7 , the grating tilt angles of both can be 90°. Optionally, the grating periods of the first coupling grating 311 and the second coupling grating 312 can be the same, for example, the grating period Period can be 390 nm. Optionally, the grating depths of the first coupling grating 311 and the second coupling grating 312 can be the same, for example, the grating depth Depth can be 300 nm (0.3 μm). Optionally, the grating refractive index n1 of the first coupling grating 311 and the second coupling grating 312 can be 1.9, the refractive index n2 of the substrate of the waveguide 30 of both can be 1.7, and the thickness of the substrate of the waveguide 30 can be 0.5 mm.

[0097] For another example, referring to the diffraction waveguide devices 300 and 400 shown in FIG3 and FIG4 , the polarization states of the first polarized light L1 and the second polarized light L2 are both S-polarized. The grating type of the first coupling grating 311 and the second coupling grating 312 can both be transmissive slanted gratings. As shown in FIG8 , the grating tilt angle θ of each can be 60°, for example. Optionally, the grating period of the first coupling grating 311 and the second coupling grating 312 can be the same, for example, the grating period Period can be 390 nm. Optionally, the grating depth of the first coupling grating 311 and the second coupling grating 312 can be the same, for example, the grating depth Depth can be 300 nm (0.3 μm). Optionally, the grating refractive index n1 of the first coupling grating 311 and the second coupling grating 312 can be 1.9, the refractive index n2 of the substrate of the waveguide 30 of each coupling grating can be 1.7, and the thickness of the substrate of the waveguide 30 can be 0.5 mm.

[0098] Optionally, the polarization states of the first polarized light L1 and the second polarized light L2 are the same, and the first coupling-in grating 311 and the second coupling-in grating 312 may adopt grating structures with completely identical grating parameters.

[0099] In some embodiments, the polarization states of the first polarized light L1 and the second polarized light L2 are different, and at least some of the grating parameters of the first coupling-in grating 311 and the second coupling-in grating 312 are different. For example, referring to the diffractive optical waveguide device 500 shown in FIG5 , the first polarized light L1 is S-polarized light, and the second polarized light L2 is P-polarized light. For the diffractive optical waveguide device 500, the grating types of the first coupling-in grating 311 and the second coupling-in grating 312 can be different. For example, the first coupling-in grating 311 can be a transmissive slanted grating as shown in FIG8 , and the second coupling-in grating 312 can be a transmissive rectangular grating as shown in FIG7 .

[0100] Optionally, the polarization states of the first polarized light L1 and the second polarized light L2 are different, and the first coupling grating 311 and the second coupling grating 312 may also adopt grating structures with completely different grating parameters, which can be flexibly set according to actual conditions.

[0101] It should be noted that the polarization states of the first polarized light L1 and the second polarized light L2 are the same or different, the first coupling grating 311 and the second coupling grating 312 can have the same grating period and grating line orientation, and should be arranged along the line grating or close to the line grating, and avoid being arranged along the direction of the light beam propagation path.

[0102] In some embodiments, the diffraction optical waveguide device may further include a coupled-out grating. As shown in FIG1a , the coupled-out grating 32 may be provided on the waveguide 30, and the coupled-out grating 32 is configured to couple the first polarized light L1 via the first coupled-in grating 311 into the optical coupled-out waveguide 30 for propagation in the waveguide 30; and to couple the second polarized light L2 via the second coupled-in grating 312 into the optical coupled-out waveguide 30 for propagation in the waveguide 30. Similarly, a coupled-out grating may be provided in the embodiments of FIG2 to FIG6 . It should be noted that in the embodiment of FIG1a , the coupled-out grating 32 and the coupled-in grating 31 are provided on the same side of the waveguide 30. Although not shown in the figure, the coupled-out grating 32 and the coupled-in grating 31 may be provided on both sides of the waveguide 30. These are all within the scope of protection of the present disclosure and are determined according to actual circumstances.

[0103] In some embodiments, the diffraction waveguide device may further include a fold / turn grating. As shown in Figures 9 and 10, the fold / turn grating 33 may be disposed on the waveguide 30 and located in the optical path between the coupling-in grating 31 and the coupling-out grating 32. In some embodiments, as shown in Figures 1a to 6, 9, and 10, the fold / turn grating 33 is configured to deflect and / or expand the pupil of the first polarized light L1 incident on the fold / turn grating 33 via the first coupling-in grating 311; and / or the fold / turn grating 33 is configured to deflect and / or expand the pupil of the second polarized light L2 incident on the fold / turn grating 33 via the second coupling-in grating 312. The size of the fold / turn grating 33 increases along the optical path of the first polarized light L1 and the second polarized light L2, so that the light incident thereon can be further deflected and / or expanded.

[0104] The present disclosure further provides an AR display system, which includes the diffraction light waveguide devices 100 to 500 described above; and / or the AR display system includes the diffraction light waveguide device 600 described above.

[0105] Figure 9 shows a schematic diagram of an AR display system 700 according to some embodiments of the present disclosure. As shown in Figure 9, the AR display system 700 can be a one-dimensional monocular monocular display system. By using a monocular and a turning grating, one-dimensional monocular deflection and / or pupil expansion can be achieved while reducing the size of the entire AR display system, resulting in better imaging quality and reduced power consumption.

[0106] Figure 10 shows a schematic diagram of an AR display system 800 according to other embodiments of the present disclosure. As shown in Figure 10, the AR display system 800 can be a one-dimensional monocular binocular display system. By using a monocular and a turning grating, one-dimensional binocular deflection and / or pupil expansion can be achieved while reducing the size of the entire AR display system, resulting in better imaging quality and reduced power consumption.

[0107] Figure 11 shows a schematic diagram of an AR display system 900 according to further embodiments of the present disclosure. As shown in Figure 11, the AR display system 900 can be a two-dimensional monocular binocular system. By using a monocular and a turning grating, two-dimensional binocular deflection and / or pupil expansion can be achieved while reducing the size of the entire AR display system, resulting in better imaging quality and reduced power consumption.

[0108] The present disclosure also provides a method for designing an in-coupling grating. Figure 12 shows a flow chart of a method 1000 for designing an in-coupling grating according to some embodiments of the present disclosure. As shown in Figure 12, the design method 1000 includes steps S1100 to S1300.

[0109] In step S1100, based on different incident lights, the coupling grating is parameter-scanned to obtain output characteristic curves that vary with the diffraction angle for different incident lights. Different incident lights include unpolarized light, S-polarized light, and P-polarized light. The grating parameters of the coupling grating may include one or more of the grating type, grating period, grating tilt angle, duty cycle, and grating depth. The grating type includes any one of a transmissive rectangular grating, a transmissive slanted grating, and a reflective blazed grating. The output characteristics may include comprehensive coupling efficiency and non-uniformity. In step S1200, based on the output characteristic curves for different incident lights, the optimized values ​​of the output characteristics for different incident lights and the optimized values ​​of the grating parameters corresponding to the optimized values ​​of the output characteristics are determined. In step S1300, based on the optimized values ​​of the grating parameters, the first coupling grating 311 and / or the second coupling grating 312 as described above are designed.

[0110] Figures 13a to 13c are schematic diagrams showing output characteristic curves that vary with diffraction angle, obtained by performing parameter scanning on the coupling grating based on unpolarized light, S-polarized light, and P-polarized light, respectively, according to some embodiments of the present disclosure. Table 1 shows the optimized values ​​and output characteristics of the grating corresponding to different incident light in the embodiments of Figures 13a to 13c. The diffraction angle variation range is, for example, Fov_x: -10° to 10°, and Fov_y: -9°. The coupling grating is, for example, a transmissive bevel grating. The tilt angle, duty cycle, and depth of the transmissive bevel grating can be subjected to three-dimensional parameter scanning to obtain the output characteristic curves shown in Figures 13a to 13c.

[0111] Table 1

[0112] As shown in Figure 13a and Table 1, based on the output characteristic curve for unpolarized light, the optimized output characteristics for unpolarized light can be determined: as shown at point A in the figure, the combined coupling efficiency is 26.3% and the non-uniformity is 26.7%. The optimized output characteristics correspond to the optimized parameters of the transmissive skew grating: a tilt angle of 68°, a grating duty cycle of 0.46, and a grating depth of 445 nm. Based on these optimized grating parameters, a first coupling grating 311 and / or a second coupling grating 312, similar to the exemplary embodiment shown in Figure 8, can be designed and applied to the diffractive optical waveguide devices 100-600 of Figures 1a to 6. Similarly, as shown in Figure 13b and Table 1, based on the output characteristic curve for S-polarized light, the optimized output characteristics for S-polarized light can be determined: as shown at point B in the figure, the combined coupling efficiency is 29.9% and the non-uniformity is 33.5%. The optimized values ​​of the transmission slanted grating parameters corresponding to the optimized output characteristics are: a tilt angle of 66°, a grating duty cycle of 0.46, and a grating depth of 460 nm. Based on the optimized values ​​of the grating parameters, a first coupling grating 311 and / or a second coupling grating 312, similar to the exemplary embodiment shown in FIG8 , can also be designed and applied to the diffractive optical waveguide devices 100-600 of FIG1 a through FIG6 .

[0113] Similarly, as shown in Figure 13c and Table 1, based on the output characteristic curve for P-polarized light, the optimized output characteristics for P-polarized light can be determined: as shown at point C in the figure, the combined coupling efficiency is 27.0% and the non-uniformity is 40.2%. The optimized output characteristics correspond to the optimized parameters of the transmissive skew grating: a tilt angle of 64°, a grating duty cycle of 0.38, and a grating depth of 315 nm. Based on these optimized grating parameters, a first coupling grating 311 and / or a second coupling grating 312, similar to the exemplary embodiment shown in Figure 8, can also be designed and applied to the diffractive optical waveguide devices 100-600 of Figures 1a to 6.

[0114] Figures 14a to 14f are schematic diagrams showing output characteristic curves that vary with diffraction angle, obtained by performing parameter scans on the coupling grating based on unpolarized light, S-polarized light, and P-polarized light, respectively, according to other embodiments of the present disclosure. Table 2 shows the optimized values ​​and output characteristics of the grating corresponding to different incident light in the embodiments of Figures 14a to 14f. The diffraction angle variation range is, for example, Fov_x: -10° to 10°, and Fov_y: -9°. The coupling grating is, for example, a transmissive rectangular grating. The duty cycle and depth of the transmissive rectangular grating can be subjected to a three-dimensional parameter scan to obtain the output characteristic curves shown in Figures 14a to 14f.

[0115] Table 2

[0116] As shown in Figures 14a and 14b and Table 2, based on the output characteristic curves for unpolarized light, the optimized output characteristics for unpolarized light can be determined: as shown at point D in the figure, the overall coupling efficiency is 14.3%, and as shown at point E in the figure, the non-uniformity is 32.1%. The optimized output characteristics correspond to the optimized parameters of the transmissive rectangular grating: a duty cycle of 0.38 and a grating depth of 200 nm. Based on these optimized grating parameters, a first coupling grating 311 and / or a second coupling grating 312, similar to the exemplary embodiment shown in Figure 7, can be designed and applied to the diffractive optical waveguide devices 100-600 of Figures 1a to 6.

[0117] Similarly, as shown in Figures 14c and 14d and Table 2, based on the output characteristic curves for S-polarized light, the optimized output characteristics for S-polarized light can be determined: as shown at point F in the figure, the overall coupling efficiency is 16.8%, and as shown at point G in the figure, the non-uniformity is 33.7%. The optimized output characteristics correspond to the optimized parameters of the transmissive rectangular grating: a grating duty cycle of 0.68 and a grating depth of 380 nm. Based on these optimized grating parameters, a first coupling grating 311 and / or a second coupling grating 312, similar to those exemplarily shown in Figure 7, can also be designed and applied to the diffractive optical waveguide devices 100-600 of Figures 1a to 6.

[0118] Similarly, as shown in Figures 14e and 14f and Table 2, based on the output characteristic curves for P-polarized light, the optimized output characteristics for P-polarized light can be determined: as shown by point H in the figure, the overall coupling efficiency is 19.7%, and as shown by point I in the figure, the non-uniformity is 54.5%. The optimized output characteristics correspond to the optimized parameters of the transmissive rectangular grating: a duty cycle of 0.34 and a grating depth of 200 nm. Based on these optimized grating parameters, a first coupling grating 311 and / or a second coupling grating 312, similar to those exemplarily shown in Figure 7, can also be designed and applied to the diffractive optical waveguide devices 100-600 of Figures 1a to 6.

[0119] Figures 15a to 15f are schematic diagrams of output characteristic curves obtained by performing parameter scanning on the coupling grating based on non-polarized light, S-polarized light, and P-polarized light according to some other embodiments of the present disclosure, respectively. The diffraction angle variation range is, for example, Fov_x: -10° to 10°, and Fov_y: -9°. The coupling grating is, for example, a transmissive rectangular grating. The duty cycle and depth of the transmissive rectangular grating can be subjected to a three-dimensional parameter scan to obtain the output characteristic curves shown in Figures 15a to 15f. The output characteristics may include +1-order efficiency and non-uniformity. As shown in Figures 15a and 15b, based on the output characteristic curves of non-polarized light, the optimized values ​​of the +1-order efficiency and the optimized values ​​of the non-uniformity of the non-polarized light can be determined, as well as the optimized values ​​of the grating parameters corresponding to the optimized values ​​of the +1-order efficiency and the optimized values ​​of the non-uniformity. Similarly, as shown in Figures 15c and 15d, based on the output characteristic curves for S-polarized light, the optimized values ​​of the output characteristics for S-polarized light and the optimized values ​​of the grating parameters corresponding to the optimized values ​​can be determined. Similarly, as shown in Figures 15e and 15f, based on the output characteristic curves for P-polarized light, the optimized values ​​of the output characteristics for P-polarized light and the optimized values ​​of the grating parameters corresponding to the optimized values ​​can be determined. Based on the optimized values ​​of the grating parameters determined in the embodiments of Figures 14a to 14f, a first coupling grating 311 and / or a second coupling grating 312 similar to the exemplary embodiment shown in Figure 7 can be designed, which can be applied to the diffractive optical waveguide devices 100 to 600 of Figures 1a to 6.

[0120] Different grating structures are suitable for incident light with different polarization states. In practical applications, the appropriate grating structure can be selected according to different requirements to obtain better output characteristics.

[0121] For example, referring to Figures 13a to 13c and Table 1, a transmissive slanted grating similar to that shown in Figure 8 is more suitable for S-polarized light, and can achieve a higher overall coupling efficiency while taking into account lower non-uniformity. It is particularly suitable for the first coupling grating 311 and the second coupling grating 312 of the diffraction light waveguide device in the embodiments of Figures 3 and 4, and the first coupling grating 311 in Figures 5 and 6. The comprehensive coupling efficiency of S-polarized light coupled into the first coupling grating 311 and / or the second coupling grating 312 is higher and the uniformity is better. The efficiency and uniformity of the light coupled into the waveguide through the first coupling grating 311 and / or the second coupling grating 312 are higher, and the uniformity is better. When used in an AR display system, it can achieve better imaging effects.

[0122] As another example, referring to Figures 14a to 15f and Table 2, a transmissive rectangular grating similar to that shown in Figure 7 is more suitable for P-polarized light, and can achieve a higher overall coupling efficiency while taking into account lower non-uniformity. It is particularly suitable for the first coupling grating 311 and the second coupling grating 312 of the diffraction optical waveguide device in the embodiment of Figure 2, and the second coupling grating 312 in the embodiment of Figure 5, so that the comprehensive coupling efficiency of P-polarized light coupled into the first coupling grating 311 and / or the second coupling grating 312 is higher and the uniformity is better.

[0123] In some embodiments, different grating structure parameters can be selected based on the different polarization states of the incident light to achieve the maximum overall coupling efficiency. For example, for S-polarized light, a transmissive slanted grating with a grating tilt angle of 66°, a duty cycle of 0.46, and a depth of 460 nm can be selected, as shown in Table 1, to achieve a maximum overall coupling efficiency of 29.9%. Alternatively, a transmissive rectangular grating with a duty cycle of 0.68 and a depth of 380 nm can be selected, as shown in Table 2, to achieve a maximum overall coupling efficiency of 16.8%. Alternatively, by comparing Tables 1 and 2, a transmissive slanted grating with a grating tilt angle of 66°, a duty cycle of 0.46, and a depth of 460 nm, corresponding to the highest overall coupling efficiency of 29.9%, can be selected. The first and second coupling gratings can be designed so that both the first and second polarized light are coupled into the waveguide at maximum coupling efficiency, respectively, through the first and second coupling gratings. This allows both polarized light to achieve maximum coupling efficiency through the same diffraction waveguide device. The case of P-polarized light is similar to that of S-polarized light and will not be further described here. For unpolarized light, a transmissive slanted grating with a tilt angle of 68°, a duty cycle of 0.46, and a depth of 445 nm, as shown in Table 1, can be selected to achieve a maximum combined coupling efficiency of 26.3%.

[0124] In some embodiments, different grating structure parameters can be selected based on the different polarization states of the incident light to achieve the lowest non-uniformity. For example, for P-polarized light, a transmissive slanted grating with a grating tilt angle of 64°, a duty cycle of 0.38, and a depth of 315 nm, as shown in Table 1, can be selected to achieve a minimum non-uniformity of 40.2%.

[0125] In some embodiments, the comprehensive coupling efficiency and non-uniformity can be combined to select appropriate grating structure parameters. In practical applications, the selection can be flexibly based on the needs.

[0126] It should be noted that the embodiments of Figures 13a to 15f are introduced using the transmission type slanted tooth grating and the transmission type rectangular grating as examples. The situations of the reflective blazed grating are similar and will not be described in detail here.

[0127] The following uses a transmissive rectangular grating as an example to explain how to calculate the comprehensive outcoupling efficiency for different incident light sources. It's understood that the situation is similar for transmissive slanted gratings and reflective blazed gratings. As shown in Figure 16 , after light enters waveguide 30 through coupling-in gratings 311 / 312 and undergoes a single total internal reflection, it is incident on the coupling-in grating again. At this point, some of the energy is diffracted in other directions, while only some is reflected. The comprehensive outcoupling efficiency is the average of the outcoupling efficiencies calculated from light incident at different positions on the coupling-in grating and transmitted through the waveguide.

[0128] For unpolarized light, it can be considered that the P-polarized light component and the S-polarized light component each account for half. Assuming that the zero-order reflectivities of the P-polarized light and the S-polarized light are Rp and Rs respectively, and the number of times the light beam is coupled into the grating and reflected is n, the comprehensive coupling efficiency E n The calculation process is as follows: E0=(E p +E s ) / 2; E1=E0*(R p +R s ) / 2; … E n =E n-1 *(R p +R s ) / 2.

[0129] For P-polarized light, it can be assumed that there is no S-polarized light component, and the comprehensive coupling efficiency E n The calculation process is as follows: E0=E p ; E1=E0*(R p / 2); … E n =E n-1 *(R p / 2).

[0130] For S-polarized light, it can be assumed that there is no P-polarized light component, and the comprehensive outcoupling efficiency E n The calculation process is as follows: E0=E s ; E1=E0*(R s / 2); … E n =E n-1 *(R s / 2).

[0131] It is understandable that the number of times n that a light beam incident from different positions is reflected by the diffraction grating may vary.

[0132] In summary, the design method of the diffraction optical waveguide device, AR display system, and coupling grating disclosed in the present invention has been introduced.

[0133] The diffraction optical waveguide device disclosed herein can achieve dual-path output of incident light with the same polarization state, as well as branched output of incident light with different polarization states, through the synergistic effect of a single optical engine, a polarization splitter component, and a waveguide. It can also reduce the size, cost, and power consumption of the diffraction optical waveguide device and have better performance.

[0134] The AR display system disclosed herein uses the above-mentioned diffraction light waveguide device, and can realize one-dimensional monocular display, one-dimensional binocular display, and two-dimensional binocular display through a single optical machine, thereby achieving better imaging effects.

[0135] The design method disclosed herein can determine the output characteristics of different incident lights based on the output characteristic curves of different incident lights, and can determine the optimized values ​​of the output characteristics of different incident lights and the optimized values ​​of the corresponding grating parameters. This allows for the design of different grating structures, and the selection of appropriate grating structures based on different requirements to achieve more optimal output characteristics. By designing the first coupling grating and the second coupling grating using the design method disclosed herein, both the first polarized light and the second polarized light can be coupled into the waveguide via the first coupling grating and the second coupling grating, respectively, with maximum coupling efficiency. This allows both polarized lights, or one polarized light and one unpolarized light, to achieve maximum coupling efficiency and / or minimized non-uniformity and / or maximum +1st-order diffraction efficiency through the same diffraction waveguide device.

[0136] It should be noted that the specific numerical values ​​of the grating parameters involved in the present disclosure are shown for illustrative purposes only and do not constitute a limitation to the present disclosure. In practical applications, they can be flexibly adjusted according to actual conditions, and all of these are within the scope of protection of the present disclosure.

[0137] It should be noted that this specification provides method operation steps as described in the embodiments or schematic diagrams, but more or fewer operation steps may be included based on routine or non-creative work. The order of steps listed in the embodiments is only one way of executing the steps among many steps and does not represent the only execution order. When a system or device product is actually executed, the method can be executed sequentially or in parallel according to the embodiment or flowchart.

[0138] Finally, it should be noted that the above description is merely a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features therein. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure.

Claims

1. A diffraction optical waveguide device, comprising an optical engine, a polarization beam splitter component, and a waveguide: in, The optical engine is configured to emit unpolarized light; The waveguide includes an incoupling grating, and the incoupling grating includes a first incoupling grating and a second incoupling grating; The polarization splitting component is arranged downstream of the optical path of the optical machine and upstream of the optical path of the coupling grating; the polarization splitting component is configured to modulate the non-polarized light emitted by the optical machine into a first polarized light and a second polarized light; and is configured to couple the first polarized light into the first coupling grating, and couple the second polarized light into the second coupling grating; The optical engine, the polarization beam splitting component and the first coupling-in grating form a first optical path for the first polarized light; The optical engine, the polarization beam splitting component and the second coupling-in grating form a second optical path for the second polarized light; Wherein, the polarization states of the first polarized light and the second polarized light are the same or different; The first polarized light and the second polarized light are either S polarized light or P polarized light respectively. 2 . The diffraction light waveguide device according to claim 1 , wherein the first polarized light and the second polarized light are both P-polarized light; or the first polarized light and the second polarized light are both S-polarized light.

3. The diffraction optical waveguide device according to claim 2, wherein the polarization beam splitting component comprises an optical path deflector, a polarization beam splitter and a polarization rotator, wherein The optical path deflector is configured to deflect the non-polarized light incident thereon; The polarization beam splitter is configured to perform polarization separation on the unpolarized light incident thereon; The polarization rotator is configured to rotate the polarization state of polarized light incident thereon.

4. The diffraction optical waveguide device according to claim 3, wherein the optical path deflector comprises a prism; and the polarization beam splitter comprises a beam splitting surface embedded in the prism; The beam splitting surface is configured to reflect or transmit a portion of the non-polarized light incident thereon to form S-polarized light, and is configured to transmit or reflect another portion of the non-polarized light incident thereon to form P-polarized light; The polarization rotator is configured to modulate the S-polarized light into P-polarized light; or modulate the P-polarized light into S-polarized light.

5. The diffraction light waveguide device according to claim 4, wherein the polarizer is arranged outside the prism and downstream of the optical path of the S-polarized light; the P-polarized light modulated by the polarizer is the first polarized light, and the P-polarized light transmitted through the splitting surface is the second polarized light.

6. The diffraction light waveguide device according to claim 4 , wherein the polarizer is arranged outside the prism and downstream of the optical path of the P-polarized light, the S-polarized light reflected by the beam splitter surface is totally reflected on the surface of the prism and then emitted as the first polarized light, and the S-polarized light modulated by the polarizer is the second polarized light; and the directions of the first polarized light and the second polarized light are parallel to the direction of the unpolarized light.

7. The diffraction light waveguide device according to claim 4, wherein the polarizer is arranged inside the prism and downstream of the optical path of the P-polarized light; the S-polarized light reflected by the beam splitter is the first polarized light; the S-polarized light modulated by the polarizer and then emitted after total reflection on the surface of the prism is the second polarized light; the directions of the first polarized light and the second polarized light are perpendicular to the direction of the unpolarized light.

8. The diffraction waveguide device according to any one of claims 3 to 7, wherein the polarizer comprises a half-wave plate, and the half-wave plate is attached to the surface of the prism. 9 . The diffraction light waveguide device according to claim 1 , wherein the first polarized light is S-polarized light, and the second polarized light is P-polarized light.

10. The diffraction light waveguide device according to claim 9, wherein the polarization splitting component comprises an optical path deflector and a polarization beam splitter; the optical path deflector comprises a prism; the polarization beam splitter comprises a splitting surface embedded in the prism; the splitting surface is configured to reflect or transmit a portion of the non-polarized light incident thereon to form S-polarized light, and is configured to transmit or reflect another portion of the non-polarized light incident thereon to form P-polarized light.

11. The diffraction light waveguide device according to claim 10, wherein the S-polarized light reflected by the beam splitting surface and then emitted after total reflection on the surface of the prism is the first polarized light; and the P-polarized light transmitted through the beam splitting surface is the second polarized light.

12. The diffraction optical waveguide device according to claim 1 , 2 or 9 , wherein the first coupling grating and the second coupling grating are arranged side by side on the same side of the waveguide; and grating parameters of the first coupling grating and the second coupling grating are respectively determined by optical parameters of the first polarized light and the second polarized light incident thereon.

13. The diffractive optical waveguide device according to claim 12, wherein the optical parameters include one or more of diffraction angle, polarization state, comprehensive coupling efficiency and non-uniformity.

14. The diffractive optical waveguide device according to claim 12, wherein the grating parameters include one or more of a grating type, a grating period, a grating tilt angle, a duty cycle, and a grating depth; wherein the grating type includes any one of a transmissive rectangular grating, a transmissive slanted grating, and a reflective blazed grating.

15. The diffraction light waveguide device according to claim 13 , wherein the polarization states of the first polarized light and the second polarized light are the same, and at least some grating parameters of the first coupling grating and the second coupling grating are the same; or the polarization states of the first polarized light and the second polarized light are different, and at least some grating parameters of the first coupling grating and the second coupling grating are different.

16. The diffraction light waveguide device according to claim 12, wherein the waveguide further comprises an outcoupling grating, the outcoupling grating being disposed on the waveguide, the outcoupling grating being configured to couple the first polarized light propagating in the waveguide coupled into the waveguide via the first incoupling grating out of the waveguide; and to couple the second polarized light propagating in the waveguide coupled into the waveguide via the second incoupling grating out of the waveguide.

17. The diffraction optical waveguide device according to claim 16, further comprising a turning grating, wherein the turning grating is arranged on the waveguide and is located in the optical path between the coupling-in grating and the coupling-out grating; the turning grating is configured to deflect and / or expand the pupil of the first polarized light incident on the turning grating via the first coupling-in grating; and / or the turning grating is configured to deflect and / or expand the pupil of the second polarized light incident on the turning grating via the second coupling-in grating.

18. The diffraction light waveguide device according to claim 17, wherein a size of the turning grating increases along the optical path direction of the first polarized light and the second polarized light.

19. The diffractive light guide device according to any one of claims 1 to 3, wherein the optical engine comprises a light source, and the light source comprises any one or more of LCOS, DLP and MicroLED.

20. A diffraction optical waveguide device comprising an optical engine, a polarization beam splitting component, and a waveguide; in, The optical engine is configured to emit a first non-polarized light; The waveguide includes an incoupling grating, and the incoupling grating includes a first incoupling grating and a second incoupling grating; The polarization splitting component is arranged downstream of the optical path of the optical machine and upstream of the optical path of the coupling grating; the polarization splitting component is configured to modulate the first non-polarized light emitted by the optical machine into a first polarized light and a second non-polarized light; and is configured to couple the first polarized light into the first coupling grating, and couple the second non-polarized light into the second coupling grating; The optical engine, the polarization beam splitting component and the first coupling-in grating form a first optical path for the first polarized light; The optical engine, the polarization beam splitting component and the second coupling-in grating form a second optical path for the second unpolarized light; Wherein, the first polarized light is any one of S polarized light and P polarized light.

21. The diffraction light waveguide device according to claim 20, wherein the polarization splitting component comprises an optical path deflector and a polarization beam splitter; the optical path deflector comprises a prism; the polarization beam splitter comprises a splitting surface embedded in the prism; the splitting surface is configured to reflect or transmit a portion of the first non-polarized light incident thereon to form S-polarized light, wherein the S-polarized light is the first polarized light, and is configured to transmit or reflect another portion of the first non-polarized light incident thereon to form P-polarized light, wherein the P-polarized light is modulated by the prism surface to form the second non-polarized light.

22. An AR display system, comprising the diffractive light waveguide device according to any one of claims 1 to 19; and / or the diffractive light waveguide device according to claim 20 or 21.

23. The AR display system according to claim 22, wherein the AR display system comprises any one of a one-dimensional monocular display system, a one-dimensional monocular binocular display system, and a two-dimensional monocular binocular system.

24. A method for designing an incoupling grating, comprising: Based on different incident lights, parameter scanning is performed on the coupling grating to obtain output characteristic curves that vary with diffraction angles for the different incident lights; Determining, based on the output characteristic curves for different incident lights, optimized values of the output characteristics for different incident lights and optimized values of the grating parameters corresponding to the optimized values of the output characteristics; and According to the optimized values of the grating parameters, designing the first coupling grating and / or the second coupling grating according to any one of claims 1 to 19; and / or Designing the first coupling-in grating and / or the second coupling-in grating according to claim 20 or 21; The different incident lights include unpolarized light, S-polarized light and P-polarized light.

25. The design method according to claim 24, wherein the grating parameters of the coupled-in grating include one or more of grating type, grating period, grating tilt angle, duty cycle and grating depth; wherein the grating type includes any one of a transmissive rectangular grating, a transmissive slanted grating and a reflective blazed grating.

26. The design method according to claim 24 or 25, wherein the output characteristics include comprehensive coupling efficiency and non-uniformity.

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