CN217007745U

CN217007745U - Waveguide substrate and augmented reality display device

Info

Publication number: CN217007745U
Application number: CN202220707805.XU
Authority: CN
Inventors: 蒋光平; 林浩翔; 萧俊龙
Original assignee: Chongqing Kangjia Photoelectric Technology Research Institute Co Ltd
Current assignee: Chongqing Kangjia Photoelectric Technology Research Institute Co Ltd
Priority date: 2022-03-28
Filing date: 2022-03-28
Publication date: 2022-07-19
Anticipated expiration: 2032-03-28

Abstract

The present application relates to a waveguide substrate including opposing first and second surfaces, and a reflective wall connected between the first and second surfaces. The light incoming region and the light outgoing region are arranged at two opposite ends of the first surface in a row along the length direction of the waveguide substrate, the second surface is provided with a reflection region opposite to the light incoming region, and the reflection region is used for reflecting part of light rays emitted from the light incoming region to the first surface and transmitting the light rays to the light outgoing region through reflection between the first surface and the second surface to be emitted. The reflecting wall is an arc surface and is positioned on one side close to the light incident area, and is used for reflecting the other part of light incident from the light incident area to the reflecting area, then at least partially reflecting the other part of light to the first surface by the reflecting area, and transmitting the light to the light emergent area through reflection between the first surface and the second surface to be emitted. Through this application waveguide substrate, can increase visual field angle and luminance. The application also provides an augmented reality display device.

Description

Waveguide substrate and augmented reality display device

Technical Field

The present application relates to the field of display technologies, and in particular, to a waveguide substrate and an augmented reality display device having the same.

Background

Augmented Reality display (AR) is a technology for superimposing virtual image information and real world information on each other, that is, superimposing a virtual image on the real world while visualizing the real world, so as to complement the real world information and the virtual image information with each other. The augmented reality display device generally utilizes a waveguide substrate to realize transmission of virtual image information, namely, the waveguide substrate utilizes a total reflection principle to realize transmission of light, and then combines a grating arranged on the surface of the waveguide substrate to realize directional incidence, directional turning and directional emergent of the light by utilizing a Bragg diffraction principle through the grating, so that the virtual image information is transmitted to human eyes, and a user can see a virtual image.

When the waveguide substrate transmits light, the bragg diffraction principle and the waveguide substrate total reflection principle are limited, and part of the light cannot be transmitted in the waveguide substrate, so that the part of the light cannot be utilized. Thereby making the augmented reality display device likely to have insufficient field brightness and small field angle.

SUMMERY OF THE UTILITY MODEL

In view of the above-mentioned shortcomings of the prior art, an object of the present application is to provide a waveguide substrate capable of increasing a viewing angle and brightness, and an augmented reality display device having the waveguide substrate.

The application provides a waveguide substrate, which comprises a light inlet area and a light outlet area, and is used for transmitting light rays emitted from the light inlet area to the light outlet area and then emitting the light rays. The light incident region and the light emergent region are arranged at two opposite ends of the first surface along the length direction of the waveguide substrate, the second surface is provided with a reflection region opposite to the light incident region, and the reflection region is used for reflecting part of light rays incident from the light incident region to the first surface and transmitting the light rays to the light emergent region through reflection between the first surface and the second surface to be emitted.

The reflecting wall is an arc surface and is positioned on one side close to the light entering area, and is used for reflecting the other part of light incident from the light entering area to the reflecting area, at least partially reflecting the other part of light to the first surface by the reflecting area, and transmitting the light to the light emitting area for emission through reflection between the first surface and the second surface.

In this embodiment, by providing the light incident region and the light exiting region at the two ends of the first surface in the length direction of the waveguide substrate, light can be made to enter between the first surface and the second surface from the light incident region, and part of the light can be made to be reflected and transmitted between the first surface and the second surface and be emitted from the light exiting region. The reflecting region is arranged at the position, opposite to the light entering region, of the second surface, so that part of light entering the light entering region is reflected by the reflecting region and then emitted onto the first surface, and is transmitted to the light emitting region through reflection between the first surface and the second surface and then emitted.

Furthermore, by arranging the reflecting wall between the first surface and the second surface, a part of light rays emitted from the light incident region to the reflecting wall can be reflected to the reflecting region, and then at least part of the light rays are reflected to the first surface by the reflecting region and transmitted to the light emergent region through reflection between the first surface and the second surface.

Through the cooperation of reflection wall and reflecting region, can will penetrate to the at least part of partial light on the reflection wall and transmit to going out the light zone to guarantee that the light from different visual angles is at least partly all can transmit in the waveguide substrate, and then improve the utilization ratio of penetrating into light from going into the light zone, increase augmented reality display device's visual field angle and luminance.

Optionally, the light entering region is provided with a first grating, and the first grating is a transmission grating and is used for diffracting light entering the light entering region.

In this embodiment, by providing the first grating in the light incident region and setting the first grating as a transmissive grating, light entering the light incident region can be diffracted, so that the light can be directed into the first surface and the second surface of the waveguide substrate.

Optionally, the reflection region is provided with a second grating, and the second grating is a reflective grating and is configured to reflect the light emitted to the reflection region to the first surface.

In this embodiment, by disposing the second grating in the reflection region and setting the second grating as a reflective grating, the light incident on the reflection region can be at least partially reflected onto the first surface to be transmitted between the first surface and the second surface in a total reflection manner.

Optionally, the waveguide substrate further includes a third grating, the third grating is disposed on the second surface and is disposed opposite to the light exit region, and the third grating is a reflective grating and is configured to reflect light to the light exit region to exit.

In this embodiment, the third grating is disposed on the second surface opposite to the light exit region, and the third grating is a reflective grating, so that the light can be reflected to the light exit region to be emitted, and the light emitted to the third grating is recombined to be emitted from the light exit region at the same angle according to the angle of light emitted from the light entrance region.

Optionally, the grating constants d of the first grating, the second grating, and the third grating are the same.

In this embodiment, a first angle is formed between the light emitted from the light emitting area and the normal of the light emitting area, a second angle is formed between a portion of the light diffracted from the first grating to the second surface and the normal of the second surface, a third angle is formed between the light reflected from the second grating to the first surface and the normal of the first surface, the second angle and the third angle can be made equal by setting the grating constants d of the first grating, the second grating and the third grating to be the same, and the first angle and the incident angle of the light from the light entering area are the same.

Optionally, the radian of the arc surface of the reflecting wall satisfies the condition: sin theta₂＝2λ/d+sinθ₁. Wherein λ is the wavelength of the light emitted from the light incident region to the reflective wall, θ 1 is the angle between the light emitted from the light incident region to the reflective wall and the normal of the light incident region, and θ 2 is the angle between the light reflected from the reflective wall to the reflective region and the normal of the reflective region.

In the present embodiment, the condition is satisfied by setting the radian of the arc surface of the reflecting wall: sin theta₂＝2λ/d+sinθ₁To be able toThe third angle which can ensure that the part of the light reflected to the second grating from the reflecting wall is transmitted to the first surface after being reflected by the second grating is equal to the second angle.

Optionally, the length S of the second grating satisfies the condition:

wherein, there is interval distance H between light entering region and the reflection region.

In the present embodiment, the condition is satisfied by setting the length S of the second grating

The second angle between the part of light diffracted from the first grating to the second surface and the normal of the second surface can be prevented from changing, namely, the second grating is prevented from influencing the transmission angle of the part of light diffracted from the first grating to the second surface, and the efficiency of light transmission is further ensured.

Optionally, the first surface and the second surface are parallel and extend along the length of the waveguide substrate.

The application also provides an augmented reality display device, which comprises a micro-display and the waveguide substrate in any one of the embodiments, wherein the micro-display is arranged relative to the light incident region and used for emitting light to the light incident region.

In this embodiment, by arranging the microdisplay and arranging the microdisplay opposite to the light-incident region, light emitted by the microdisplay and carrying virtual image information can be emitted to the light-incident region.

Optionally, the augmented reality display device further comprises a collimator lens disposed between the microdisplay and the waveguide substrate for converting light rays emitted from the microdisplay into parallel light rays.

In this embodiment, through setting up the collimating mirror to locate the collimating mirror between microdisplay and waveguide substrate, can change the light that emits from the microdisplay into parallel light, and then can improve the light homogeneity that gets into the waveguide substrate, improve the display effect of augmented reality display device virtual image after the transmission.

Drawings

Fig. 1 is a schematic view of a working scene of an augmented reality display device according to the present application;

FIG. 2 is a schematic side view diagram of an augmented reality display device according to an embodiment of the present disclosure;

FIG. 3 is a schematic view of a waveguide substrate according to the present application;

FIG. 4 is a schematic diagram of the transmission process of 0 th order diffracted light rays of the embodiment shown in FIG. 3 in the waveguide substrate of the present application;

FIG. 5 is a schematic diagram illustrating a transmission process of light rays in the waveguide substrate of the present application when the first included angle is 0 degrees;

FIG. 6 is a schematic view of an embodiment of light propagating in a waveguide substrate of the present application;

fig. 7 is a schematic structural diagram of a conventional waveguide substrate at a side view angle.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

The following description of the various embodiments refers to the accompanying drawings, which are included to illustrate specific embodiments that can be implemented by the application. The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" as used herein includes both direct and indirect connections (couplings), unless otherwise specified. Directional phrases used in this application, such as, for example, "upper," "lower," "front," "rear," "left," "right," "inner," "outer," "side," and the like, refer only to the orientation of the appended drawings and are, therefore, used herein for better and clearer illustration and understanding of the application and are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the application.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; may be a mechanical connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art. It should be noted that the terms "first", "second", and the like in the description and claims of the present application and in the drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "comprises," "comprising," "includes," "including," or "including," when used in this application, specify the presence of stated features, operations, elements, and/or the like, but do not limit one or more other features, operations, elements, and/or the like. Furthermore, the terms "comprises" or "comprising" indicate the presence of the respective features, numbers, steps, operations, elements, components or combinations thereof disclosed in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, components or combinations thereof, and are intended to cover non-exclusive inclusions.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

Referring to fig. 1, fig. 1 is a schematic view of a working scene of an augmented reality display device 1 according to the present application. The augmented reality display device 1 includes a waveguide substrate 10 and a microdisplay 20, and as shown in fig. 1, the microdisplay 20 is located on one side of the waveguide substrate 10 and is disposed opposite to a light incident region 111 of the waveguide substrate 10.

The microdisplay 20 is used for loading virtual image information and emits the light G with the virtual image information to the light incident region 111 of the waveguide substrate 10, so that the waveguide substrate 10 can emit the light G with the virtual image information from the light emergent region 112 of the waveguide substrate 10 and transmit the light to the human eye E, thereby enabling the user to see the virtual image information loaded by the microdisplay 20.

The micro display 20 may be a Liquid Crystal On Silicon (LCOS) chip, a Digital micro mirror Device (Digital micro mirror Device), an organic electroluminescent Device, or a scanning image display Device.

An embodiment please refer to fig. 2, and fig. 2 is a schematic structural diagram of an augmented reality display device 1 at a side view angle in this embodiment. As shown in fig. 2, the augmented reality display device 1 further includes a collimator lens 30, and the collimator lens 30 is disposed between the microdisplay 20 and the waveguide substrate 10, and is used for converting light L emitted from the microdisplay 20 into parallel light La.

In this embodiment, by providing the collimating mirror 30 and disposing the collimating mirror 30 between the microdisplay 20 and the waveguide substrate 10, the light L emitted from the microdisplay 20 can be converted into the parallel light La, so that the uniformity of the light L entering the waveguide substrate 10 can be improved, and the display effect of the virtual image of the augmented reality display device 1 after transmission is improved.

Referring to fig. 3, fig. 3 is a schematic structural diagram of a side view of a waveguide substrate 10 according to the present application. The waveguide substrate 10 of the present application includes opposing first and

second surfaces

11 and 12, and a reflective wall 13 connected between the first and

second surfaces

11 and 12. In the embodiment shown in fig. 3, the first surface 11 and the second surface 12 are parallel to each other and extend in the first direction 001. Here, the first direction 001 is a longitudinal direction of the waveguide substrate 10. In other embodiments of the present application, the first surface 11 and the second surface 12 may also be arcs of the same curvature.

The material of the waveguide substrate 10 may be an inorganic material or an organic material having optical transparency, and the material of the waveguide substrate 10 also has a high refractive index so that the difference between the refractive index of the waveguide substrate 10 and the refractive index of the medium (e.g., air) around the waveguide substrate is increased, thereby achieving better light transmission.

Further, as shown in fig. 3, the first surface 11 includes a light incident region 111 and a light exiting region 112, the light incident region 111 and the light exiting region 112 are arranged at two opposite ends of the first surface 11 along a first direction 001, and the light L is incident from the light incident region 111 and is output to the light exiting region 112 through transmission. In the embodiment shown in fig. 3, the light L is incident on the light incident region at a first included angle θ 1 and exits from the light exiting region 112 at a first angle μ 1.

The first angle θ 1 is an angle between the incident direction of the light L and the normal of the light incident region 111, and the first angle μ 1 is an angle between the light L emitted from the light emitting region 112 and the normal of the light emitting region 112.

The second surface 12 includes a reflective region 121, and the reflective region 121 is disposed opposite to the light incident region 111, and is configured to reflect a portion of the light L incident from the light incident region 111 to the first surface 11 at a third angle μ 3 (see fig. 4), and transmit the light L to the light exit region 112 along the first direction 001 in a form of total reflection between the first surface 11 and the second surface 12 to exit at the first angle μ 1.

The reflecting wall 13 is a cambered surface and is located on a side close to the light incident region 111 and far away from the light emergent region 112. The reflective wall 13 is used for reflecting another part of the light L incident from the light incident region 111 onto the reflective region 121 at a second included angle θ 2 (see fig. 4), and then the reflective region 121 reflects at least a part of the another part of the light L onto the first surface 11, and transmits the light L to the light exit region 112 in a total reflection manner between the first surface 11 and the second surface 12 to exit at a first angle μ 1.

The second included angle θ 2 is an included angle between a direction of the other part of the light L emitted from the reflective wall 13 to the reflective area 121 and a normal of the reflective area 121.

In the embodiment of the present application, the reflecting wall 13 satisfies the condition:

sinθ₂＝2λ/d+sinθ₁。

where λ is the wavelength of the light L incident on the reflective wall 13 from the light incident region 111.

The waveguide substrate 10 of the present application further includes a first grating 14, a second grating 15, and a third grating 16. The first Grating 14, the second Grating 15, and the third Grating 16 may be at least one of Volume Grating (Volume Grating), Holographic Grating (Holographic Grating), or Surface Relief Grating (Surface Relief Grating).

Specifically, as shown in fig. 3, the first grating 14 is disposed in the light incident region 111, and is a transmissive grating having a first grating constant d 1. The first grating 14 is for diffracting the light L incident on the light incident region 111. Wherein, a second angle μ 2 is formed between a part of the light L diffracted from the first grating 14 to the second surface 12 and the normal of the second surface 12.

By providing the first grating 14 in the light incident region 111 and setting the first grating 14 as a transmissive grating, the light L entering the light incident region 111 can be diffracted so that the light L can be directed into the first surface 11 and the second surface 12 of the waveguide substrate.

The second grating 15 is disposed in the reflective region 121 and is opposite to the first grating 14. The second grating 15 is a reflective grating having a second grating constant d 2. The second grating 15 is used for reflecting at least part of the light L incident on the reflection region 121 to the first surface 11.

By arranging the second grating 15 in the reflection region 121 and setting the second grating 15 as a reflective grating, the light L incident on the reflection region 121 can be at least partially reflected onto the first surface 11 to be transmitted between the first surface 11 and the second surface 12 by total reflection.

The third grating 16 is disposed on the second surface 12 and is opposite to the light exit area 112. The third grating 16 is a reflective grating having a third grating constant d 3. The third grating 16 is used for reflecting the light L to the light emergent area 112 for emitting.

By providing the third grating 16 in the region of the second surface 12 facing the light exit region 112 and making the third grating 16 a reflective grating, the light L can be reflected to the light exit region 112 and emitted, and the light L emitted to the third grating 16 can be recombined to be emitted from the light exit region 112 at the same angle according to the angle of incidence from the light entrance region 111, i.e. the first angle μ 1 is the same as the first included angle θ 1.

In the embodiment of the present application, the first grating constant d1, the second grating constant d2, and the third grating constant d3 are equal.

Specifically, in the embodiment shown in fig. 3, when the light L is incident on the first grating 14 at the first included angle θ 1, the light L is diffracted by the first grating 14 into diffracted lights of different diffraction orders, including-1 order diffracted light (not shown), 0 order diffracted light L0 (see fig. 4), and +1 order diffracted light L + 1.

The light energy of the light L with different diffraction orders is different, the light energy carried by the 0 th order diffracted light L0 is the strongest, and is greater than the light energy of the +1 st order diffracted light L +1 and greater than the light energy of the-1 st order diffracted light L-1.

When the light L is diffracted into the waveguide substrate 10 of the present application, different diffraction angles exist for diffracted light of different diffraction orders. The diffraction angle of the +1 st order diffracted light L +1 satisfies the total reflection condition of the waveguide substrate 10, that is, the diffraction angle of the +1 st order diffracted light L +1 incident on the second surface 12 of the waveguide substrate 10 is greater than the total reflection critical angle of the waveguide substrate 10, and then the +1 st order diffracted light L +1 will be transmitted in the waveguide substrate 10 in a total reflection manner.

Further, as shown in fig. 3, the +1 order diffracted light L +1 is incident on the second surface 12 at a second angle μ 2, and is totally reflected between the first surface 11 and the second surface 12 along the first direction 001 several times, that is, the +1 order diffracted light L +1 is transmitted along the first direction 001 at the second angle μ 2.

When the +1 order diffracted light L +1 is transmitted to the third grating 16, it exits from the light exit area 112 through the third grating 16 at the first angle μ 1. Since the first grating constant d1 of the first grating 14 is equal to the third grating constant d3 of the third grating 16, the third grating 16 is a reflective grating. Therefore, the first angle μ 1 at which the +1 order diffracted light L +1 exits from the light exit region 112 through the third grating 16 is the same as the first included angle θ 1 at which the light entrance region 111 enters. That is, by making the first angle μ 1 equal to the first included angle θ 1, lossless transmission of the light L can be achieved, thereby enabling the user to see the virtual image loaded by the microdisplay 20.

In one embodiment, as shown in fig. 3, the length S of the second grating 15 satisfies the condition:

where H is the separation distance between the light incident region 111 and the reflective region 121.

That is, in the present embodiment, the condition is satisfied by setting the length S of the second grating 15

Can avoid on light L shines second grating 15 through +1 st order diffraction light L +1 behind the first grating 14 diffraction, and then avoid +1 st order diffraction light L + 1's total reflection angle to change. That is, the second angle μ 2 at which the +1 st order diffracted light L +1 is prevented from being incident on the second surface 12 is changed.

Further, by preventing the +1 st order diffracted light L +1 from being emitted to the second grating 15 after the light L is diffracted by the first grating 14, the efficiency of transmitting the light L in the waveguide substrate 10 can be ensured, and the display effect of the virtual image of the microdisplay 20 on the human eye E after being transmitted through the waveguide substrate 10 can be ensured.

Further, referring to fig. 4, fig. 4 is a schematic diagram illustrating a transmission process of 0 th order diffracted light L0 of the light L in the embodiment shown in fig. 3 in the waveguide substrate 10 of the present application. The light L is emitted to the first grating 14 at the first included angle θ 1, and the 0-order diffracted light L0 is continuously emitted to the reflective wall 13 at the first included angle θ 1 and is reflected to the reflective region 121 at the second included angle θ 2, i.e. the 0-order diffracted light L0 is reflected to the second grating 15 at the second included angle θ 2.

When the 0 th order diffracted light L0 is incident on the second grating 15, it is reflected by the second grating 15. Specifically, as shown in fig. 4, the 0 th order diffracted light L0 incident on the second grating 15 is further reflected as +1 st order diffracted light L +1a and is incident on the first surface 11 at a third angle μ 3.

Since the radian of the arc surface of the reflecting wall 13 satisfies the condition: sin theta₂＝2λ/d+sinθ₁And the first grating constant d1 of the first grating 14 is equal to the second grating constant d2 of the second grating 15. Therefore, the third angle μ 3 of the +1 st order diffracted light L +1a is equal to the second angle μ 2 of the +1 st order diffracted light L + 1.

Further, the light L reflected by the reflective wall 13 is incident on the second grating 15, and the +1 st order diffracted light L +1a reflected by the second grating 15 is transmitted between the first surface 11 and the second surface 12 at the second angle μ 2 to the third grating 16 in a form of total reflection, and is emitted from the light emitting region 112 at the first angle μ 1. Since the first grating constant d1 and the third grating constant d3 are equal, the first angle μ 1 and the first included angle θ 1 are equal, and the lossless transmission of the light L at the viewing angle shown in fig. 3 can be realized.

That is, by making the radian of the arc surface of the reflecting wall 13 satisfy the condition: sin theta₂＝2λ/d+sinθ₁After the 0-order diffracted light L0 is set on the second grating 15 from the reflective wall 13, the third angle μ 3 at which the reflected + 1-order diffracted light L +1a is incident on the first surface 11 is equal to the second angle μ 2 at which the + 1-order diffracted light L +1 is incident on the second surface 12, so as to ensure that the transmission efficiency of the light L is improved, and ensure that the virtual image of the microdisplay 20 is transmitted to the human eye E.

Further, in the present embodiment, by the cooperation of the reflective wall 13 and the second grating 15, the 0 th order diffracted light L0 with the strongest light energy in the light L can be further diffracted into the +1 st order diffracted light L +1a, and the +1 st order diffracted light L +1a is transmitted between the first surface 11 and the second surface 12 at the same total reflection angle as the +1 st order diffracted light L + 1. With the effective rate that improves light L transmission in this application waveguide substrate 10, and light L's utilization ratio, and then can improve human eye E and see the visual field luminance of virtual image through this application augmented reality display device 1, improved user's use and experienced the sense.

Further, by providing the reflecting wall 13, the viewing angle range in which the light L can be transmitted in the waveguide substrate 10 can be increased. In other words, the range of the first included angle θ 1 can be increased, and the field of view of the augmented reality display device 1 of the present application can be enlarged.

Referring to fig. 5, fig. 5 is a schematic view illustrating a transmission process of a light L in the waveguide substrate 10 when a first included angle θ 1 is 0 degree. When the first included angle θ 1 is 0 degree, the light L perpendicularly irradiates the first grating 14 along the normal direction of the light incident region 111.

As shown in fig. 5, when the light L is vertically incident on the first grating 14, the light L is diffracted into diffracted lights of different diffraction orders through the first grating 14, including-1 order diffracted light (not shown), 0 order diffracted light L0 and +1 order diffracted light L + 1.

The +1 st order diffracted light L +1 is emitted onto the second surface 12 at the second angle μ 2a, and is totally reflected between the first surface 11 and the second surface 12 at the second angle μ 2a along the first direction 001 several times, that is, the +1 st order diffracted light L +1 is transmitted onto the third grating 16 at the second angle μ 2a along the first direction 001, and is reflected by the third grating 16 to be emitted from the light emitting area 112 at the first angle μ 1a to the human eye E. The first angle μ 1a is equal to the first included angle θ 1, that is, the light L is emitted from the light-emitting area 112 perpendicularly.

As shown in fig. 5, the 0 th order diffracted light L0 will be incident perpendicularly on the second grating 15, and further reflected as +1 st order diffracted light L +1a on the second grating 15, and will be incident on the first surface 11 at a third angle μ 3 a. And further transmitted between the first surface 11 and the second surface 12 at a third angle μ 3a along the first direction 001 to the third grating 16, and exits from the light exit region 112 at a first angle μ 1 a.

Referring to fig. 6, fig. 6 is a schematic view illustrating a transmission process of a light L in the waveguide substrate 10 when a first included angle θ 1 is θ 1 b. As shown in fig. 6, the incident angle of the light L incident on the light incident region 111 is θ 1 b. That is, the light L is incident on the first grating 14 at the first included angle θ 1b, and is diffracted into-1 st-order diffracted light (not shown), 0 th-order diffracted light L0 and +1 st-order diffracted light L +1 by the first grating 14.

The +1 order diffracted light L +1 is emitted onto the second surface 12 at a second angle μ 2b, transmitted between the first surface 11 and the second surface 12 along the first direction 001 at the second angle μ 2b to the third grating 16, and reflected by the third grating 16 to be emitted from the light exit area 112 at the first angle μ 1b to the human eye E. Wherein the first angle μ 1b is equal to the first included angle θ 1 b.

The 0 th order diffracted light L0 continues to be incident on the second grating 15 at the first angle θ 1b, is further reflected by the second grating 15 as +1 st order diffracted light L +1a, and is incident on the first surface 11 at the third angle μ 3 b. And is totally reflected between the first surface 11 and the second surface 12 at a third angle μ 3b along the first direction 001 to the third grating 16, and exits from the light exit area 112 at a first angle μ 1 b.

Referring to fig. 7, fig. 7 is a schematic structural view of a conventional waveguide substrate 3 at a side view angle. As shown in fig. 7, a first grating 32 is provided in a light entrance region 31 of a conventional waveguide substrate 3, and a second grating 34 is provided at a position facing a light exit region 33. The first grating 32 is a transmissive grating, and the second grating 34 is a reflective grating. Further, the conventional waveguide substrate 3 has a side wall 35 close to the light-entrance region 31 and distant from the light-exit region 33, and as shown in fig. 7, the side wall 35 is a flat surface. When the 0 th order diffracted light L0 of the light L is incident on the side wall 35, the light is directly transmitted from the side wall 35 into the conventional waveguide substrate 3 and cannot be transmitted through the conventional waveguide substrate 3.

Due to the limitation of the waveguide structure and the grating structure, the conventional waveguide substrate 3 can only perform total reflection transmission on + 1-order diffracted light, and the 0-order diffracted light L0 with the strongest light energy is directly transmitted from the conventional waveguide substrate 3, so that the 0-order diffracted light L0 with the strongest light energy cannot be utilized. Thereby resulting in a low utilization of the light L and thus a low field brightness of the existing augmented reality display device. Moreover, light rays emitted by the micro-display at certain viewing angles cannot be transmitted in the existing waveguide substrate 3, so that the existing augmented reality display device is small in viewing field angle and low in user experience.

In the waveguide substrate 10 of the present invention, the light incident region 111 and the light exiting region 112 are respectively disposed at two ends of the first surface 11 along the length direction of the waveguide substrate 10, the first grating 14 is disposed in the light incident region 111, and the third grating 16 is disposed at a position corresponding to the light exiting region 112 on the second surface 12. And further, the light L is incident from the light incident region 111, diffracted into 0-order diffracted light L0 and + 1-order diffracted light L +1 by the first grating 14, and the + 1-order diffracted light L +1 is totally reflected between the first surface 11 and the second surface 12 at the second angle μ 2 in the first direction 001, and transmitted to the third grating 16, and the light L transmitted at the third grating 16 is recombined to be emitted from the light emitting region 112 at the same angle according to the incident angle from the light incident region 111, i.e., the first angle μ 1 is the same as the first included angle θ 1.

Further, the waveguide substrate 10 of the present application is configured such that the reflective region 121 is disposed on the second surface 12 at a position opposite to the light incident region 111, and the second grating 15 is disposed in the reflective region 121. And the 0 th order diffracted light L0 diffracted by the first grating 14 is incident on the second grating 15, and is diffracted for the second time by the second grating 15, so that the 0 th order diffracted light L0 is further reflected as +1 st order diffracted light L +1a, and is incident on the first surface 11 at a third angle μ 3, and is transmitted to the third grating 16 between the first surface 11 and the second surface 12 at the third angle μ 3 in a form of total reflection, and is emitted from the light emitting area 112.

Further, the first grating constant d1, the second grating constant d2, and the third grating constant d3 are set to be equal. And then the second angle μ 2 between the +1 st order diffracted light L +1a and the +1 st order diffracted light L +1 reflected from the second grating 15 ensures the efficiency of the transmission of the light L in the waveguide substrate 10 and the display effect of transmitting the virtual image of the microdisplay 20 to the human eye E.

Further, by disposing the reflective wall 13 between the first surface 11 and the second surface 12, a portion of the light L emitted from the micro-display 20 at different angles through the light incident region 111 and incident on the reflective wall 13 can be reflected onto the reflective region 121, and then the portion of the light L is at least partially reflected onto the first surface 11 by the reflective region 121 and transmitted to the light exiting region 112 through the first surface 11 and the second surface 12 in a total reflection manner.

That is, the waveguide substrate 10 of the present application can transmit at least part of the partial light L emitted to the reflective wall to the light emitting region 112 through the matching of the reflective wall 13 and the reflective region 121, so as to ensure that at least part of the light L from different viewing angles can be transmitted in the waveguide substrate 10, thereby improving the utilization rate of the light L emitted from the light incident region 111, and increasing the viewing angle and the brightness of the augmented reality display device 1 of the present application.

The augmented reality display device 1 of the present application employs the waveguide substrate 10 of the present application, and thus has all the advantageous technical effects that the waveguide substrate 10 of the present application may have. In addition, by using the waveguide substrate 10 of the present invention, the field brightness and the field angle of the augmented reality display device 1 of the present invention can be improved.

It is to be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit ly indicating a number of technical features being indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the embodiments of the present application, "a plurality" means two or more unless specifically defined otherwise.

In the description herein, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example" or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

It should be understood that the application of the present application is not limited to the above examples, and that modifications or changes may be made by those skilled in the art based on the above description, and all such modifications and changes are intended to fall within the scope of the appended claims. It will be understood by those skilled in the art that all or part of the above-described embodiments may be implemented and equivalents may be made thereto without departing from the scope of the utility model as defined by the appended claims.

Claims

1. A waveguide substrate, comprising a light inlet region and a light outlet region, for transmitting light entering from the light inlet region to the light outlet region, and a reflective wall connected between the first surface and the second surface, wherein the light inlet region and the light outlet region are arranged at two opposite ends of the first surface along the length direction of the waveguide substrate, the second surface is provided with a reflective region opposite to the light inlet region, and the reflective region is used for reflecting part of light entering from the light inlet region to the first surface and transmitting the part of light to the light outlet region via reflection between the first surface and the second surface;

the reflecting wall is an arc surface and is positioned on one side close to the light incident area, and is used for reflecting another part of light incident from the light incident area to the reflecting area, then the reflecting area reflects at least part of the other part of light to the first surface, and the other part of light is transmitted to the light emergent area to be emitted through reflection between the first surface and the second surface.

2. The waveguide substrate of claim 1, wherein the light incident area is provided with a first grating, and the first grating is a transmissive grating and is configured to diffract light entering the light incident area.

3. The waveguide substrate according to claim 2, wherein the reflective region is provided with a second grating, and the second grating is a reflective grating and is configured to reflect the light incident on the reflective region to the first surface.

4. The waveguide substrate according to claim 3, further comprising a third grating disposed on the second surface and opposite to the light emergent region, wherein the third grating is a reflective grating and configured to reflect light to the light emergent region for emission.

5. The waveguide substrate according to claim 4, wherein the grating constants d of the first, second, and third gratings are the same.

6. The waveguide substrate of claim 5, wherein the reflective walls areThe radian of the cambered surface meets the condition: sin theta₂＝2λ/d+sinθ₁；

Wherein λ is a wavelength of light irradiated from the light incident region onto the reflecting wall, and θ₁Is the angle between the light ray irradiated from the light incident region to the reflecting wall and the normal of the light incident region₂Is the included angle between the light reflected to the reflecting area from the reflecting wall and the normal of the reflecting area.

7. The waveguide substrate according to claim 6, wherein the length L of the second grating satisfies the condition:

wherein, a spacing distance H is arranged between the light incoming region and the reflection region.

8. The waveguide substrate of any one of claims 1-6, wherein the first surface and the second surface are parallel and extend along a length of the waveguide substrate.

9. An augmented reality display device comprising a microdisplay disposed relative to the light-incident region for emitting light into the light-incident region, and the waveguide substrate of any one of claims 1-8.

10. The device of claim 9, further comprising a collimating mirror disposed between the microdisplay and the waveguide substrate for converting light rays emitted from the microdisplay into parallel light rays.