Waveguide module and augmented reality device

Abstract

The application provides a waveguide module and an augmented reality device. The waveguide module comprises an optical waveguide configured to transmit an optical signal incident on the optical waveguide, the optical waveguide comprising an out-coupling grating having an effective window region with a center point; and a protective cover plate stacked and spaced apart from the optical waveguide and configured to protect the optical waveguide, the protective cover plate having a first surface facing away from the optical waveguide, the first surface having a normal line, and the direction of ambient light incident on the first surface from the side of the protective cover plate facing away from the optical waveguide and away from the normal line to the side of the center point being a preset direction, the protective cover plate being configured to adjust the propagation direction of ambient light incident on the protective cover plate from the preset direction to reduce the incident angle of ambient light in the preset direction on the out-coupling grating. The waveguide module can effectively improve the rainbow phenomenon of the waveguide module, better avoid the serious interference of the rainbow with the normal line of sight of the human eye, and reduce visual fatigue caused by long-term wearing.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of augmented reality technology, in particular to a waveguide module and an augmented reality device. BACKGROUND

[0002] Augmented reality (AR) technology can combine virtual and reality, and has been more and more widely applied. Light waveguide is an essential element of augmented reality device, and the out-coupling grating of light waveguide is used to deflect the light in the light waveguide by a certain angle, so that the light enters the human eye. When the ambient light is incident on the out-coupling grating, if the incident angle of the ambient light is higher than a certain critical angle, the diffraction angle of the ambient light passing through the out-coupling grating is lower than the total reflection angle, and the ambient light will be coupled out into the human eye. Since the ambient light is mixed by light of different colors, the wavelengths of light of different colors are different, and the diffraction angles are different, therefore, when the ambient light passes through the out-coupling grating and enters the human eye, light of different colors will enter the human eye at different angles, and therefore a linear or halo color image, i.e. rainbow stripe, will be felt, which will seriously interfere with the normal vision of the human eye, and long-term wearing will easily cause visual fatigue. SUMMARY

[0003] In view of the above problems, the embodiments of the present application provide a waveguide module which can effectively improve the rainbow stripe phenomenon of the waveguide module, and better avoid the serious interference of the rainbow stripe with the normal vision of the human eye, and long-term wearing will not easily cause visual fatigue.

[0004] In a first aspect, the present application provides a waveguide module, comprising:

[0005] a light waveguide, the light waveguide being used for transmitting an optical signal incident on the light waveguide, the light waveguide comprising an out-coupling grating, the out-coupling grating having an effective window region, the effective window region having a center point; and

[0006] a protective cover plate, the protective cover plate being stacked and spaced apart from the light waveguide and being used for protecting the light waveguide, the protective cover plate having a first surface facing away from the light waveguide, the first surface having a normal line, the direction of ambient light incident on the first surface from the side of the protective cover plate facing away from the light waveguide and away from the center point side of the normal line being a preset direction, the protective cover plate being used for adjusting the propagation direction of ambient light incident on the protective cover plate from the preset direction, so as to reduce the incident angle of the ambient light of the preset direction incident on the out-coupling grating.

[0007] In a second aspect, the present application provides an augmented reality device, comprising:

[0008] a projection light machine, the projection light machine being used for projecting an optical signal, the optical signal comprising image information;

[0009] The waveguide module in the first aspect of the present application is used for transmitting the optical signal, and the protective cover plate is farther away from the projection light machine than the optical waveguide; and

[0010] A processor is electrically connected with the projection light machine, and is used for controlling the projection light machine to project the optical signal.

[0011] The waveguide module in the embodiment of the present application comprises a protective cover plate, which can adjust the propagation direction of ambient light incident to the protective cover plate from the preset direction, so as to reduce the incident angle of the ambient light in the preset direction to the out-coupling grating, so that the ambient light with a larger incident angle has a smaller angle after passing through the protective cover plate, so that the proportion of ambient light greater than the critical angle in the ambient light incident to the out-coupling grating is greatly reduced, and the proportion of ambient light coupled out by the out-coupling grating into the human eye is also greatly reduced, so that the rainbow phenomenon of the waveguide module can be greatly weakened, and the normal line of sight of the human eye can be better avoided from being seriously disturbed by the rainbow, and visual fatigue can be avoided from being easily caused by long-term wearing. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0013] Figure 1 For the case that the thicknesses of the protective cover plates are equal, the propagation direction of ambient light is shown.

[0014] Figure 2 is a top view structural schematic diagram of the waveguide module of an embodiment of the present application.

[0015] Figure 3 is a sectional view structural schematic diagram of the waveguide module of an embodiment of the present application along Figure 2 the A-A direction.

[0016] Figure 4 is an enlarged view of the dashed box I. Figure 3

[0017] Figure 5 is a top view structural schematic diagram of the optical waveguide of an embodiment of the present application.

[0018] Figure 6 is a light path schematic diagram of ambient light in the second direction incident to the protective cover plate.

[0019] Figure 7 is a top view structural schematic diagram of the optical waveguide of another embodiment of the present application. ​

[0020] Figure 8 is a schematic view of a waveguide module along the direction B-B in Figure 5 FIG. 2 is a schematic view of a partial cross-sectional structure of the waveguide module along the direction B-B in

[0021] Figure 9 is a schematic view of a waveguide module along the direction B-B in

[0022] Figure 10 is a schematic view of a waveguide module along the direction C-C in Figure 9 FIG. 6 is a schematic view of a partial cross-sectional structure of the waveguide module along the direction C-C in

[0023] Figure 11 is a schematic view of a waveguide module along the direction C-C in Figure 10 FIG. 8 is a schematic view of a partial cross-sectional structure of the waveguide module along the direction C-C in

[0024] Figure 12 is a schematic view of a waveguide module along the direction C-C in Figure 9 FIG. 10 is a schematic view of a partial cross-sectional structure of the waveguide module along the direction C-C in

[0025] Figure 13 is a schematic view of a waveguide module along the direction C-C in Figure 9 FIG. 12 is a schematic view of a partial cross-sectional structure of the waveguide module along the direction C-C in

[0026] Figure 14 is a schematic view of a waveguide module along the direction C-C in

[0027] Figure 15 is a schematic view of a waveguide module along the direction C-C in Figure 14 FIG. 18 is a schematic view of a waveguide module along the direction C-C in

[0028] Figure 16 is a schematic view of a waveguide module along the direction C-C in

[0029] Figure 17 is a schematic view of a waveguide module along the direction C-C in Figure 16 FIG. 24 is a schematic view of a waveguide module along the direction C-C in

[0030] Figure 18 is a schematic view of a waveguide module along the direction C-C in

[0031] Figure 19 is a schematic view of a waveguide module along the direction C-C in Figure 18 FIG. 30 is a schematic view of a waveguide module along the direction D-D in

[0032] Figure 20 is a schematic view of a waveguide module along the direction C-C in

[0033] BRIEF DESCRIPTION OF THE DRAWINGS

[0034] 10a-optical waveguide, 13a-out-coupling grating, 20a-protection cover, 100-waveguide module, 10-optical waveguide, 11-light conducting layer, 12-in-coupling grating, 13-out-coupling grating, 131-effective window area, O-center point, 132-middle axis, 14-turning grating, 20-protection cover, 21-body part, 211-second surface, 212-fourth surface, 22-light adjusting part, 221-first surface, 222-third surface, 223-groove, 30-protection layer, 40-first adhesive, 50-second adhesive, 20b-glass substrate, 10b-photoresist layer, 11b-uneven structure, 23-substrate layer, 24-light adjusting layer, 10c-texture mold, 11c-texture structure, 24c-photo-curing adhesive layer, 400-augmented reality device, 410-projection light machine, 411-display, 413-lens, 420-carrier, 430-wearing part, 431-first wearing subpart, 433-second wearing subpart, 440-processor, 460-memory. DETAILED DESCRIPTION

[0035] In order to make the personnel in the technical field better understand the scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0036] The terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product or device.

[0037] The technical scheme in the embodiments of the present application will be described below in combination with the drawings.

[0038] It should be noted that, for the sake of illustration, in the embodiments of the present application, the same reference signs represent the same parts, and for the sake of brevity, detailed description of the same parts is omitted in different embodiments.

[0039] The metaverse is based on extended reality technology to provide immersive experience, based on digital twin technology to generate a mirror image of the real world, based on blockchain technology to build an economic system, to closely integrate the virtual world and the real world in the economic system, social system, identity system, and allow each user to produce content and edit the world. Among them, the extended reality technology (XR) is the basis of the metaverse, including virtual reality technology (VR), AR and mixed reality technology (MixedReality, MR) and other technologies.

[0040] Augmented reality is a technology that provides users with an enhanced perception of reality by superimposing computer-generated images into real-world images input into the human eye. It has been increasingly widely used. Optical waveguide is a medium device that guides the propagation of light waves, and is an essential element of augmented reality devices. Optical waveguide includes geometric optical waveguide and diffractive optical waveguide. Compared with geometric optical waveguide, the grating of diffractive optical waveguide has higher flexibility in design and production, higher mass production and yield, and therefore is more widely used. For example, the diffractive optical waveguide scheme of AR glasses is a mainstream technical scheme because its optical lens is light and thin, its appearance is closer to traditional glasses, and it is easier to produce. Diffractive optical waveguide can be further divided into surface relief grating and volume holographic grating.

[0041] The out-coupling grating of the optical waveguide is used to deflect the light in the optical waveguide by a certain angle so that the light enters the human eye. Figure 1 To protect the cover plate 20a, the propagation direction of the ambient light is shown in the figure. Please refer to Figure 1 , the surface of the optical waveguide 10a is usually provided with a protective cover plate 20a. When the protective cover plate 20a is a cover plate with equal thickness, when the ambient light is incident on the protective cover plate 20a at an incident angle of θ1, the protective cover plate 20a cannot change the propagation direction of the light, therefore, after the ambient light is emitted through the protective cover plate 20a, it will also be incident on the out-coupling grating 13a at an angle of θ1. When the ambient light is incident on the out-coupling grating 13a, if the incident angle of the ambient light is higher than a certain critical angle, the diffraction angle of the ambient light through the out-coupling grating 13a is lower than the total reflection angle, and the ambient light will be coupled out into the human eye. Since the ambient light is a mixture of different colors of light, the wavelengths of different colors of light are different, and the diffraction angles are different, therefore, when the ambient light is coupled into the human eye through the out-coupling grating 13a, different colors of light will enter the human eye at different angles, and therefore a linear or halo color image, i.e. rainbow stripes, will be perceived, which will seriously interfere with the normal line of sight of the human eye, and long-term wearing will easily cause visual fatigue and damage the wearer's glasses.

[0042] The "critical angle" of the present application refers to a critical angle at which, when ambient light is incident to the out-coupling grating, the diffraction angle of the ambient light passing through the out-coupling grating is lower than the total reflection angle of the ambient light in the optical waveguide, after the incident angle is higher than the critical angle. That is, the critical angle of the ambient light incident to the out-coupling grating reaches the critical angle of generating rainbow stripes. The critical angle is related to the total reflection angle of the optical fiber in the optical waveguide, the period of the out-coupling grating, and the refractive index of the optical waveguide.

[0043] Figure 2 FIG. 1 is a top view of a waveguide module 100 according to an embodiment of the present application. Figure 3 FIG. 2 is a sectional view of the waveguide module 100 along direction A-A in FIG. 1. Figure 2 FIG. 3 is an enlarged view of the dashed box I in FIG. 2. Figure 4 FIG. 4 is a top view of an optical waveguide 10 according to an embodiment of the present application. Figure 3 FIG. 5 is an enlarged view of the dashed box I in FIG. 4. Figure 5 FIG. 6 is a sectional view of the optical waveguide 10 along direction A-A in FIG. 4.

[0044] FIG. 7 is a sectional view of the optical waveguide 10 along direction B-B in FIG. 4. Figures 2 to 5 According to an embodiment of the present application, a waveguide module 100 is provided, which includes an optical waveguide 10 and a protective cover plate 20. The optical waveguide 10 is configured to transmit an optical signal incident to the optical waveguide 10. The optical waveguide 10 includes an out-coupling grating 13 configured to couple the optical signal incident to the optical waveguide 10 out of the optical waveguide 10 to be coupled into an eye. The out-coupling grating 13 has an effective eyebox 131 with a center point O. The protective cover plate 20 is stacked and spaced apart from the optical waveguide 10 and configured to protect the optical waveguide 10. The protective cover plate 20 has a first surface 221 facing away from the optical waveguide 10. The first surface 221 has a normal line. A direction of ambient light incident to the first surface 221 from a side of the protective cover plate 20 facing away from the optical waveguide 10 and away from the center point O is a preset direction. The protective cover plate 20 is configured to adjust a propagation direction of the ambient light incident to the protective cover plate 20 from the preset direction (e.g., the ambient light P in FIG. 6) to reduce an incident angle of the ambient light incident to the out-coupling grating 13 from the preset direction. It can be understood that the protective cover plate 20 is also configured to protect the optical waveguide 10 to improve the drop resistance and scratch resistance of the optical waveguide 10. Figure 3

[0045] The waveguide module 100 according to an embodiment of the present application can be applied to an augmented reality device. The augmented reality device according to an embodiment of the present application can be, but is not limited to, an augmented reality glasses, an augmented reality helmet, an augmented reality mask, and the like near-eye display systems.

[0046] It should be noted that the normal line of the first surface 221 refers to a straight line perpendicular to the first surface 221.

[0047] ​The term "Eye Box" in this application refers to a cone-shaped area between the near-eye display optical module (such as waveguide module 100) and the eyeball, which is also the area where the displayed content is clearest. "Central axis 132 perpendicular to the effective viewing window area 131" refers to an axis passing through the center of the Eye Box and perpendicular to the plane where the coupling grating 13 is located or the plane where the effective viewing window area 131 is located.

[0048] It should be noted that when the waveguide module 100 is in use, ambient light enters the protective cover 20 from the side facing away from the optical waveguide 10. After refraction by the protective cover 20, it passes through the protective cover 20 and finally enters the optical waveguide 10. Understandably, when the waveguide module 100 is in use, the protective cover 20 acts as an outer protective lens for the waveguide module 100, and the protective cover 20 is further away from the wearer than the optical waveguide 10.

[0049] Please see Figure 4 In this scheme, the incident surface of the protective cover 20 is inclined (i.e., the first surface 221 is inclined). Using the normal to the protective cover 20 to illustrate the light path, the incident angle of the ambient light in the preset direction on the protective cover 20 is α. Figure 1 Compared to the case where the cover plate thickness is equal, the incident angle of the ambient light in the preset direction is still θ1 (with the vertical normal as a reference, i.e., with the normal of the coupling grating 13 as a reference), which makes it easy to compare the two cover plates under the same ambient light incidence. Figure 4 The sloping cover plate and Figure 1 The change in the refraction of ambient light by the surface of the cover plate 20. After the ambient light in the preset direction is refracted by the protective cover plate 20 and incident on the coupling grating 13, the angle between the ambient light in the preset direction and the axis perpendicular to the coupling grating 13 is θ2, then θ1 is greater than θ2.

[0050] Understandably, θ1 is shown for easy reference and represents the incident angle (i.e. the angle between the light ray and the normal to the plane where the coupling grating 13 is located) of the ambient light in the preset direction when no protective cover is provided or the protective cover is of equal thickness. α represents the incident angle of the ambient light in the same direction on the cover 20 of this solution. θ2 is the incident angle of the ambient light in the preset direction after its propagation direction is changed by the protective cover 20 of the inclined surface of this application and then it is incident on the coupling grating 13.

[0051] The waveguide module 100 of the embodiment of the present application comprises a protective cover plate 20, which can adjust the propagation direction of ambient light incident to the protective cover plate 20 from the preset direction, so as to reduce the incident angle of the ambient light of the preset direction incident to the out-coupling grating 13, so that the ambient light with a larger incident angle has a smaller angle of incidence to the out-coupling grating 13 after passing through the protective cover plate 20, so that the proportion of ambient light greater than the critical angle incident to the out-coupling grating 13 is greatly reduced, and the proportion of ambient light coupled out of the out-coupling grating 13 into the human eye is also greatly reduced, so that the rainbow phenomenon of the relief diffraction waveguide module 100 can be greatly weakened, and the rainbow phenomenon can be better avoided to seriously interfere with the normal line of sight of the human eye, and visual fatigue is easy to occur after long-term wearing.

[0052] It should be noted that after the ambient light is incident to the out-coupling grating 13, the ambient light with an incident angle less than the critical angle will propagate in the optical waveguide 10 and finally propagate to the edge of the optical waveguide 10, which is absorbed by the black ink of the edge of the optical waveguide 10 and does not affect the display of the optical waveguide 10.

[0053] Figure 6 is a schematic diagram of the light path of ambient light of the second direction incident to the protective cover plate. Please refer to Figure 6 , for the convenience of description and division, the ambient light of the preset direction is also referred to as ambient light of the first direction, and the direction of ambient light incident to the first surface 221 from the side of the protective cover plate 20 away from the optical waveguide 10 and from the side of the normal close to the center point is the second direction (for example Figure 6 ambient light Q in the center). The protective cover plate 20 is also used for adjusting the propagation direction of ambient light incident to the protective cover plate 20 from the second direction, for increasing the incident angle of ambient light incident to the protective cover plate 20 from the second direction, so that the ambient light incident from the second direction is offset towards the direction away from (or far from) the center point O when incident to the optical waveguide 10, and then the ambient light incident from the second direction is increased, and the light rays incident to the out-coupling grating 13 are reduced, so that the rainbow phenomenon of the waveguide module 100 can be better weakened.

[0054] It can be understood that compared with the direction in which the thickness of the protective cover plate is equal, the protective cover plate 20 adopting the present scheme can offset the ambient light incident from the second direction towards the direction away from the center point, so that more ambient light of the second direction is offset out of the area of the out-coupling grating 13, the probability of ambient light of the second direction incident to the out-coupling grating 13 is reduced, and the proportion of ambient light coupled out of the out-coupling grating 13 into the human eye is reduced, so that the rainbow phenomenon of the diffraction waveguide module 100 can be greatly weakened.

[0055] Please refer again to Figure 5The light waveguide 10 further comprises a light transmission layer 11 and an in-coupling grating 12, which is arranged on the surface of the light transmission layer 11 facing the protective cover plate 20. The light transmission layer 11 is configured to transmit the optical signal entering the light transmission layer 11. The in-coupling grating 12 is configured to couple the optical signal into the light transmission layer 11. The out-coupling grating 13 is configured to couple the optical signal transmitted by the light transmission layer 11 out of the light waveguide 10.

[0056] It can be understood that the in-coupling grating 12 can deflect the optical signal (i.e. light ray) incident by the projection light machine of the augmented reality device by a certain angle by using the grating diffraction effect, so as to meet the total reflection condition in the light transmission layer 11, so that the optical signal continuously undergoes total reflection in the light transmission layer 11, thereby realizing the transmission of the optical signal. When the optical signal is transmitted to the out-coupling grating 13, the out-coupling grating 13 deflects the optical signal by a certain angle again to couple the optical signal out of the light waveguide 10, so that the light ray enters the eye of the wearer.

[0057] Optionally, the in-coupling grating 12 can be, but is not limited to, one of a binary grating, an inclined grating, a blazed grating, a two-dimensional grating, etc. The out-coupling grating 13 can be, but is not limited to, one of a binary grating, an inclined grating, a blazed grating, a two-dimensional grating, etc. The types of the in-coupling grating 12 and the out-coupling grating 13 can be the same or different.

[0058] Figure 7 is a top view structural schematic diagram of the light waveguide 10 according to another embodiment of the present application. Please refer to Figure 7 In some other embodiments, the light waveguide 10 further comprises a turning grating 14 configured to expand the pupil of the image information in the optical signal. The turning grating 14, the in-coupling grating 12 and the out-coupling grating 13 are respectively arranged on the surface of the light transmission layer 11 away from the protective cover plate 20. When the light waveguide 10 further comprises the turning grating 14, the optical signal coupled into the light transmission layer 11 by the in-coupling grating 12 first undergoes pupil expansion by the turning grating 14, and then is coupled out of the light waveguide 10 by the out-coupling grating 13. Optionally, the turning grating 14 can be, but is not limited to, one of a binary grating, an inclined grating, a blazed grating, a two-dimensional grating, etc. The types of the turning grating 14, the in-coupling grating 12 and the out-coupling grating 13 can be the same or different.

[0059] Please refer to Figure 5 and Figure 8In some embodiments, the out-coupling grating 13 further has a center point O and a middle axis 132 perpendicular to the effective window area 131, the protective cover plate 20 comprises a body part 21 and a light adjusting part 22, the body part 21 is stacked and spaced apart from the light waveguide 10, the light adjusting part 22 is arranged on the side of the body part 21 away from the light waveguide 10 and surrounds the outer periphery of the middle axis 132, the light adjusting part 22 has a first surface 221, the body part 21 has a second surface 211 facing the light waveguide 10, the second surface 211 is a plane, the distance from the first surface 221 to the second surface 211 gradually increases from the position close to the middle axis 132 to the position away from the middle axis 132, so as to adjust the propagation direction of the ambient light incident on the protective cover plate 20 from the preset direction (i.e. the first direction), so as to reduce the incident angle of the ambient light from the preset direction to the out-coupling grating 13; at the same time, it is also used for making the ambient light incident from the second direction deviate towards the direction away from the center point O after passing through the protective cover plate 20 and then being incident on the light waveguide 10, so as to increase the light rays of the ambient light incident from the second direction and deviated out of the area of the out-coupling grating 13 and reduce the light rays incident on the out-coupling grating 13, so as to better weaken the rainbow stripe phenomenon of the waveguide module 100.

[0060] Optionally, the light adjusting part 22 is rotationally symmetrical about the middle axis 132.

[0061] Understandably, the thickness of the protective cover plate 20 is not uniform, and the thickness of the light adjusting part 22 gradually increases from the position close to the middle axis 132 to the position away from the middle axis 132 along the stacking direction of the light waveguide 10 and the protective cover plate 20.

[0062] Understandably, when the number of the light adjusting part 22 is one, the thickness of the light adjusting part 22 gradually increases from the position of the middle axis 132 to the position away from the middle axis 132. In other words, the thickness of the protective cover plate 20 at the position of the middle axis 132 is thin, and the thickness of the periphery gradually increases.

[0063] In some embodiments, the body part 21 and the light adjusting part 22 can be an integral structure. In other words, the body part 21 and the light adjusting part 22 are two different parts of the same component. In other words, the body part 21 and the light adjusting part 22 have the same material or raw material composition, for example, the body part 21 and the light adjusting part 22 are both glass materials or both resin materials. In other embodiments, the body part 21 and the light adjusting part 22 are two connected components, and the body part 21 and the light adjusting part 22 have different material compositions, for example, the body part 21 is a glass material and the light adjusting part 22 is a resin material.

[0064] In the embodiment, when the ambient light of the preset direction is incident on the protective cover plate 20, the ambient light of the preset direction is first refracted by the first surface 221 for the first time, and then is refracted by the first surface 221 for the second time. Since the distance from the first surface 221 to the second surface 211 of the light adjusting part 22 gradually increases from the position close to the central axis 132 to the direction away from the central axis 132, the angle of the ambient light emitted by the protective cover plate 20 and incident on the out-coupling grating 13 is greatly reduced, the proportion of the ambient light greater than the critical angle incident on the out-coupling grating 13 is greatly reduced, and the proportion of the ambient light coupled out of the out-coupling grating 13 into the human eye is also greatly reduced, so that the rainbow phenomenon of the waveguide module 100 can be greatly weakened, the normal line of sight of the human eye is better avoided from being seriously disturbed by the rainbow, and visual fatigue is easy to occur after long-term wearing. When the ambient light of the second direction is incident on the protective cover plate 20, the ambient light of the second direction is first refracted by the first surface 221 for the first time, and then is refracted by the first surface 221 for the second time. Since the distance from the first surface 221 to the second surface 211 of the light adjusting part 22 gradually increases from the position close to the central axis 132 to the direction away from the central axis 132, after the ambient light of the second direction is incident on the protective cover plate 20, the ambient light of the second direction is incident on the light waveguide 10 and is offset to the direction away from the center point O, so that the light rays of the ambient light of the second direction offset out of the region of the out-coupling grating 13 are increased, and the light rays incident on the out-coupling grating 13 are reduced, so that the rainbow phenomenon of the waveguide module 100 can be better weakened.

[0065] Please refer to Figure 9 and Figure 10 In some other embodiments, the number of the light adjusting parts 22 is multiple, and the multiple light adjusting parts 22 are arranged around the outer periphery of the central axis 132, and are sequentially arranged from the central axis 132 to the direction away from the central axis 132 along the extension plane of the body part 21.

[0066] The term “multiple” in the present application refers to at least two or greater than or equal to two.

[0067] The number of the light adjusting parts 22 in the embodiment can be, but is not limited to, two, three, four, five, six, seven, eight, etc. The more the number of the light adjusting parts 22 is, the more conducive to the thinning of the protective cover plate 20, but the more the number of the light adjusting parts 22 is, the more the processing cost of the protective cover plate 20 is increased.

[0068] Optionally, the multiple light adjusting parts 22 are coaxially arranged. Desirably, the light adjusting part 22 closest to the central axis 132 is a circular structure with a conical groove, and the remaining light adjusting parts 22 are annular structures. The multiple light adjusting parts 22 are like a ring, one is sleeved on the outer periphery of the other, and are sequentially arranged from the central axis 132 to the direction away from the central axis 132.

[0069] Optionally, the plurality of light adjusting portions 22 are arranged in sequence in close proximity. Understandably, there is no gap between any two adjacent light adjusting portions 22, and the minimum gap between any two adjacent light adjusting portions 22 is zero.

[0070] When the number of light adjusting portions 22 is only one, the thickness of the position of the protective cover plate 20 away from the central axis 132 (i.e. closer to the edge) is thicker, which not only affects the appearance effect of the protective cover plate 20, but also greatly increases the weight of the protective cover plate 20, and long-term wearing will bring discomfort to the wearer of the augmented reality device with the waveguide module 100. In the embodiment of the present application, according to the differential principle similar to the Fresnel lens, the first surface 221 is differentiated and reorganized, and a plurality of light adjusting portions 22 are used instead of one light adjusting portion 22, which not only can maintain the function of adjusting the propagation direction of ambient light by the light adjusting portion 22, but also can greatly reduce the thickness of the protective cover plate 20, which is beneficial to the lightness and thinness of the waveguide module 100.

[0071] Optionally, the light adjusting portion 22 further has a third surface 222 connected to the bending of the first surface 221, and the third surface 222 is perpendicular to the second surface 211.

[0072] Understandably, the third surface 222 is perpendicular to the second surface 211, and the first surface 221 is arranged obliquely to the second surface 211, so that the first surface 221 of one of the two adjacent light adjusting portions 22 and the third surface 222 of the other are enclosed to form a groove 223. The plurality of grooves 223 are arranged around the outer periphery of the central axis 132, and along the extension plane of the body portion 21, the plurality of grooves 223 are arranged in sequence from the central axis 132 to the direction away from the central axis 132.

[0073] Optionally, the plurality of grooves 223 are coaxially arranged. Understandably, the groove 223 is an annular structure, and the plurality of grooves 223 are arranged like a ring, one on the outer periphery of the other, and arranged in sequence from the central axis 132 to the direction away from the central axis 132.

[0074] In the embodiment, when the angle between the third surface 222 and the second surface 211 is not 90°, it is easy to cause image distortion of the image displayed by the waveguide module 100, therefore, the third surface 222 is perpendicular to the second surface 211, which can better prevent the image distortion of the image displayed by the waveguide module 100.

[0075] Please refer to Figure 11Optionally, along the stacking direction of the body portion 21 and the light adjusting portion 22, the height h of the light adjusting portion 22 ranges from 0.76 μm to 300 μm. In other words, along the direction parallel to the central axis 132, the height h of the light adjusting portion 22 ranges from 0.76 μm to 300 μm. In yet another way, along the direction parallel to the central axis 132, the depth of the groove 223 ranges from 0.76 μm to 300 μm. Specifically, along the stacking direction of the body portion 21 and the light adjusting portion 22, the height h of the light adjusting portion 22 can be, but is not limited to, 0.76 μm, 0.8 μm, 0.9 μm, 1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, etc. The wavelength of visible light ranges from 380 nm to 760 nm. When the height h of the light adjusting portion 22 is lower than 760 nm (i.e. 0.76 μm), part of the visible light in the ambient light can directly pass through the light adjusting portion 22, and no obvious refraction phenomenon occurs, so that the propagation direction of the ambient light passing through the protective cover plate 20 cannot be changed. When the height h of the light adjusting portion 22 is greater than 300 μm, the protective cover plate 20 can obviously see stripes, which affects the appearance effect of the protective cover plate 20.

[0076] In the embodiments of the present application, when a numerical range a to b is involved, if not specifically indicated, it means that the numerical value can be any numerical value between a and b, including the end point value a and the end point value b.

[0077] Further, along the stacking direction of the body portion 21 and the light adjusting portion 22, the height h of the light adjusting portion 22 ranges from 1 μm to 80 μm. When the height of the light adjusting portion 22 is in this range, the propagation direction of the ambient light can be changed, and the light adjusting portion 22 is not visible to the naked eye, so that the protective cover plate 20 has a better appearance effect.

[0078] Optionally, the width w of the light adjusting portion 22 in the direction perpendicular to the central axis 132 is in the range of 7.6 μm≤w≤300 μm. In other words, the line width w of the light adjusting portion 22 is in the range of 7.6 μm≤w≤300 μm. Specifically, the width w of the light adjusting portion 22 in the direction perpendicular to the central axis 132 can be, but is not limited to, 7.6 μm, 8.5 μm, 10 μm, 15 μm, 20 μm, 50 μm, 80 μm, 100 μm, 120 μm, 130 μm, 150 μm, 180 μm, 200 μm, 220 μm, 250 μm, 280 μm, 300 μm, etc. When the width of the light adjusting portion 22 is less than 7.6 μm, the width of the light adjusting portion 22 is less than 10 times the wavelength of visible light, which causes the light adjusting portion 22 to have a diffraction grating effect, resulting in colored fringes of the ambient light refracted after passing through the light adjusting portion 22, which can be clearly seen by the protective cover plate 20, affecting the appearance of the waveguide module 100. When the width w of the light adjusting portion 22 is too large, the thickness of the protective cover plate 20 is large, which is not conducive to the thinness of the waveguide module 100. When the width w of the light adjusting portion 22 in the direction perpendicular to the central axis 132 is in the range of 7.6 μm≤w≤300 μm, the colored fringes of the protective cover plate 20 can be avoided, and the protective cover plate 20 can be made thinner, and the rainbow phenomenon of the waveguide module 100 can be reduced, avoiding the rainbow phenomenon interfering with the normal vision of the human eye, and long-term wearing can cause visual fatigue, so that the waveguide module 100 has better display effect.

[0079] Further, the width w of the light adjusting portion 22 in the direction perpendicular to the central axis 132 is in the range of 8 μm≤w≤80 μm. In this way, the colored fringes of the protective cover plate 20 can be prevented, and the protective cover plate 20 can be made thinner, improving the comfort of the wearer of the augmented reality device having the waveguide module 100.

[0080] Further, the values of h and w are near the small end point value, which can achieve excellent appearance effect, but the manufacturing cost can be high. For example, h is near 0.76 μm (e.g., 1 μm≤h≤80 μm), and w is near 7.6 μm (e.g., 8 μm≤w≤80 μm). The values of h and w are near the large end point value, which can ensure good appearance effect, but the manufacturing cost is lower. For example, h is near 300 μm (e.g., 200 μm≤h≤300 μm), and w is near 300 μm (e.g., 200 μm≤h≤300 μm).

[0081] Optionally, the first surface 221 is conical or frustoconical, and an angle θ between the first surface 221 and the second surface 211 ranges from 10° to 80°.

[0082] It can be understood that the first surface 221 is in the shape of a side surface of a cone or a side surface of a frustum. The first surface 221 of the light adjusting portion 22 closest to the central axis 132 is conical, and the first surface 221 of the light adjusting portion 22 other than the portion closest to the central axis 132 (i.e., the remaining light adjusting portions 22) is frustoconical.

[0083] Specifically, the angle θ between the first surface 221 and the second surface 211 can be, but is not limited to, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, or the like. If the angle θ between the first surface 221 and the second surface 211 is too large or too small, the protective cover plate 20 has a too small adjustment range for the propagation direction of the ambient light incident on the protective cover plate 20, and the improvement of the rainbow phenomenon is not significant. When the angle θ between the first surface 221 and the second surface 211 is between 10° and 80°, the incident angle of the ambient light incident on the out-coupling grating 13 can be greatly reduced, and the rainbow phenomenon of the waveguide module 100 can be better improved.

[0084] Please refer to Figure 12 Optionally, the projections of the plurality of light adjusting portions 22 on the second surface 211 at least cover the projections of the out-coupling grating 13 on the second surface 211, and the projections of the plurality of light adjusting portions 22 on the second surface 211 are staggered with the projections of the in-coupling grating 12 on the second surface 211. In other words, the light adjusting portion 22 is not arranged on the portion of the protective cover plate 20 stacked with the in-coupling grating 12, and the light adjusting portion 22 is arranged only on the portion of the protective cover plate 20 other than the portion stacked with the in-coupling grating 12. In this embodiment, the light adjusting portion 22 is arranged on the area of the protective cover plate 20 other than the portion stacked with the in-coupling grating 12, so that the rainbow phenomenon caused by the ambient light incident on the out-coupling grating 13 from each direction on the side of the protective cover plate 20 away from the light waveguide 10 can be better improved.

[0085] In a specific embodiment, the light adjusting portion 22 is arranged on the portion of the protective cover plate 20 other than the portion stacked with the in-coupling grating 12.

[0086] In some embodiments, the body portion 21 further has a fourth surface 212 facing away from the second surface 211, and the fourth surface 212 is flush with the end of the light conditioning portion 22 facing away from the body portion 21. In other words, the fourth surface 212 is in the same plane as the end of the light conditioning portion 22 facing away from the body portion 21. It can be appreciated that the orthographic projection of the in-coupling grating 12 falls within the range of the fourth surface 212. The end of the light conditioning portion 22 being flush with the fourth surface 212 can simplify the manufacturing process of the protective cover plate 20, and can further reduce the probability of the end of the light conditioning portion 22 facing away from the body portion 21 being scratched, thereby improving the service life of the protective cover plate 20.

[0087] Optionally, the protective cover plate 20 can be light-transmissive or semi-light-transmissive (e.g., black, brown, gray, etc.). Optionally, the material of the protective cover plate 20 can be at least one of a glass material or a resin material. The resin material can be, but is not limited to, at least one of polymethyl methacrylate, polycarbonate, etc.

[0088] Optionally, the thickness of the protective cover plate 20 can be 0.3 mm to 1 mm; specifically, can be, but is not limited to, 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, etc. If the protective cover plate 20 is too thin, it cannot provide sufficient protection for the optical waveguide 10; if the protective cover plate 20 is too thick, it increases the thickness of the waveguide module 100, which is not conducive to the light and thin of the waveguide module 100.

[0089] Please refer to Figure 13 In some embodiments, the waveguide module 100 of the embodiments of the present application further comprises a protective layer 30, which is stacked and spaced apart from the side of the optical waveguide 10 facing away from the protective cover plate 20, for protecting the optical waveguide 10. It can be appreciated that the protective cover plate 20, the optical waveguide 10, and the protective layer 30 are sequentially stacked and spaced apart. By providing the protective layer 30, the surface of the optical waveguide 10 facing the wearer can also be protected, which can better prevent the optical waveguide 10 from being scratched, improve the drop resistance of the optical waveguide 10, and improve the service life of the waveguide module 100.

[0090] Optionally, the thickness of the protective layer 30 is uniform, and the protective layer 30 cannot change the incident angle of the ambient light incident to the out-coupling grating 13. It can be appreciated that the surface of the protective layer 30 facing the optical waveguide 10 is parallel to the surface of the protective layer 30 facing away from the optical waveguide 10.

[0091] Optionally, the protective layer 30 can be light-transmissive or semi-light-transmissive (e.g., black, brown, gray, etc.). Optionally, the material of the protective layer 30 can be at least one of a glass material or a resin material. The resin material can be, but is not limited to, at least one of polymethyl methacrylate, polycarbonate, etc.

[0092] Optionally, the thickness of the protective layer 30 can be 0.3mm to 1mm; specifically, but not limited to, 0.3mm, 0.5mm, 0.8mm, 1mm, etc. If the protective layer 30 is too thin, it cannot provide sufficient protection for the optical waveguide 10; if the protective layer 30 is too thick, it increases the thickness of the waveguide module 100, which is not conducive to the lightness and thinness of the waveguide module 100.

[0093] In some embodiments, the waveguide module 100 further comprises a first adhesive 40 and a second adhesive 50; the first adhesive 40 is arranged between the optical waveguide 10 and the protective cover plate 20, and surrounds the outer periphery of the optical waveguide 10, for bonding the protective cover plate 20 to the optical waveguide 10, and spacing the optical waveguide 10 and the protective cover plate 20 apart; the second adhesive 50 is arranged between the optical waveguide 10 and the protective layer 30, and surrounds the outer periphery of the optical waveguide 10, for bonding the protective layer 30 to the optical waveguide 10, and spacing the optical waveguide 10 and the protective layer 30 apart.

[0094] Optionally, the first adhesive 40 and the second adhesive 50 are both middle frame structures or ring structures; optionally, the first adhesive 40 can be, but is not limited to, a glue frame, optical glue (O, i.e. CA glue), etc.; the second adhesive 50 can be, but is not limited to, a glue frame, optical glue (O, i.e. CA glue), etc.

[0095] Please refer to Figure 14 and Figure 15 The embodiments of the present application also provide a preparation method of the protective cover plate 20, which comprises:

[0096] S201, providing a glass substrate 20b;

[0097] Optionally, the glass substrate 20b can be, but is not limited to, at least one of quartz glass, silicate glass, soda-lime glass, fluoride glass, high-temperature glass, high-pressure resistant glass, ultraviolet-resistant glass, explosion-proof glass, etc.

[0098] S202, coating a photoresist layer 10b on the glass substrate 20b, and forming a concave-convex structure 11b on the side of the photoresist layer 10b away from the glass substrate 20b; and

[0099] Optionally, the photoresist layer 10b is formed by coating a photoresist solution on the glass substrate 20b, and the concave-convex structure 11b is made on the photoresist layer 10b by using a semiconductor process such as photolithography, wherein the concave-convex structure 11b is the same as the texture pattern composed of a plurality of light adjusting portions 22.

[0100] S203, dry etching the glass substrate 20b with the photoresist layer 10b to form the light adjustment portion 22 on the surface of the glass substrate 20b to obtain the protective cover plate 20.

[0101] Optionally, the photoresist layer 10b and the glass substrate 20b are etched by dry etching process such as plasma etching process to etch the light adjustment portion 22 on the surface of the glass substrate 20b to obtain the protective cover plate 20. The protective cover plate 20 includes the body portion 21 and the light adjustment portion 22. The body portion 21 is stacked and spaced apart from the optical waveguide 10. The light adjustment portion 22 is disposed on the side of the body portion 21 away from the light adjustment portion 22 and surrounds the outer periphery of the central axis 132. The body portion 21 has a second surface 211 facing the optical waveguide 10. The second surface 211 is a plane. The light adjustment portion 22 has a first surface 221 away from the second surface 211. The distance between the first surface 221 and the second surface 211 gradually increases from the position close to the central axis 132 to the position away from the central axis 132, so as to adjust the propagation direction of the ambient light incident on the protective cover plate 20, and reduce the incident angle of the ambient light incident on the out-coupling grating 13.

[0102] It can be understood that in the embodiment, the body portion 21 and the light adjustment portion 22 of the protective cover plate 20 are integrated structures and are both made of glass.

[0103] For detailed description of other aspects of the protective cover plate 20, please refer to the description of the corresponding part of the above embodiment, which will not be repeated here.

[0104] For detailed description of other aspects of the protective cover plate 20, please refer to the description of the corresponding part of the above embodiment, which will not be repeated here. Figure 16 Figure 17 The embodiment of the present application also provides a preparation method of the protective cover plate 20. The preparation method includes:

[0105] S301, providing a texture mold 10c having a texture structure 11c;

[0106] Optionally, a silicon-based wafer or a glass-based wafer is used, and an exposure etching process (i.e. a semiconductor process) is used to prepare the texture structure 11c on the surface of the silicon-based wafer or the glass-based wafer to obtain the texture mold 10c.

[0107] In other embodiments, the texture mold 10c can also be a sub-mold. That is, a master mold is first prepared by using an exposure development process, and then the texture structure 11c is transferred to the sub-mold by using the master mold through a texture transfer process. Finally, the sub-mold is used as a mold for subsequent nano-imprinting or UV transfer.

[0108] S302, providing a substrate layer 23; ​

[0109] Optionally, the substrate layer 23 can be, but is not limited to, at least one of polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), polycarbonate (PC). In other embodiments, the substrate layer 23 can also be a glass substrate.

[0110] S303, forming a light-cured glue layer 24c on the substrate layer 23;

[0111] Optionally, after coating the surface of the substrate layer 23 with light-cured glue, such as ultraviolet light-cured glue (UV glue), and removing the solvent, the light-cured glue layer 24c is formed.

[0112] Optionally, the light-cured glue includes polyurethane acrylate oligomer, photoinitiator, solvent, and auxiliary agent, etc.

[0113] S304, stacking the texture mold 10c on the surface of the light-cured glue layer 24c away from the substrate layer 23, and making the texture structure 11c of the texture mold 10c face the light-cured glue layer 24c; and

[0114] Optionally, the texture mold 10c is stacked on the light-cured glue layer 24c and is embossed, and a texture pattern complementary to the texture structure 11c is embossed on the light-cured glue layer 24c.

[0115] S305, light-curing the light-cured glue layer 24c to form a light adjustment layer 24, and removing the texture mold 10c to obtain a protective cover plate 20, the protective cover plate 20 comprising a substrate layer 23 and a light adjustment layer 24 stacked, the light adjustment layer 24 comprising at least one light adjustment part 22, the at least one light adjustment part 22 being complementary to the structure of the texture structure 11c; the part of the light adjustment layer 24 except the light adjustment part 22 forms a body part 21 with the substrate layer 23.

[0116] Optionally, at least one of ultraviolet light, such as mercury lamp, LED, etc. is used to irradiate the light-cured glue layer 24c, so that the light-cured glue layer 24c undergoes crosslinking reaction and thus solidifies to form the light adjustment layer 24.

[0117] The at least one light adjustment part 22 is complementary to the structure of the texture structure 11c, which can be understood that when the light adjustment layer 24 is arranged in combination with the texture mold 10c, the protruding part of the at least one light adjustment part 22 fills the recessed part of the texture structure 11c, and the recessed part between the at least one light adjustment part 22 fills the recessed part of the texture structure 11c.

[0118] Compared with the protective cover plate 20 prepared by using a photolithography process, the protective cover plate 20 prepared by using the nanoimprint or UV transfer process can improve the production efficiency of the protective cover plate 20 and reduce the production cost of the protective cover plate 20.

[0119] For details of other aspects of the protective cover plate 20, refer to the description of the corresponding part of the above embodiment, which is not repeated here.

[0120] For details of other aspects of the protective cover plate 20, refer to the description of the corresponding part of the above embodiment, which is not repeated here. Figures 18 to 20 The embodiment of the present application also provides an augmented reality device 400, which comprises a projection light machine 410, the waveguide module 100 of the above embodiment of the present application, and a processor 440. The projection light machine 410 is used for projecting a light signal, and the light signal comprises image information. The waveguide module 100 is used for transmitting the light signal. The processor 440 is electrically connected with the projection light machine 410, and is used for controlling the projection light machine 410 to project the light signal, so as to display the image information.

[0121] The augmented reality device 400 of the embodiment of the present application can be, but is not limited to, an augmented reality glasses, an augmented reality helmet, an augmented reality mask, and the like near-eye display system. In the drawings of the present application, the augmented reality device 400 is taken as an example of augmented reality glasses, which should not be understood as a limitation of the augmented reality device 400 of the present application, nor should it be understood as a limitation of the waveguide module 100 of the present application.

[0122] For details of other aspects of the protective cover plate 20, refer to the description of the corresponding part of the above embodiment, which is not repeated here.

[0123] Optionally, the projection light machine 410 comprises a display 411 and a lens 413. The display 411 is electrically connected with the processor 440, and is used for emitting a light signal with image information under the control of the processor 440. The lens 413 is arranged on the display side of the display 411, and is used for modulating the light signal, so that the light rays (light signal) with different field angles of view emitted by the same pixel point on the display 411 are modulated by the lens 413 in the form of parallel light, so as to project the image information in the light signal at an infinite position, so that the naked eye can watch it. The waveguide module 100 is arranged on the side of the lens 413 away from the display 411, and is used for transmitting the light signal modulated by the lens 413.

[0124] In an embodiment, the coupling-in grating 12 and the coupling-out grating 13 of the optical waveguide 10 are arranged away from the projection light machine 410. In another embodiment, the coupling-in grating 12 and the coupling-out grating 13 of the optical waveguide 10 are arranged to face the projection light machine 410.

[0125] In some embodiments, the waveguide module 100 can also expand the pupil of the image information in the light signal emitted by the lens 413 in one or two dimensions to increase the range of the eyebox, thereby accommodating a larger population.

[0126] Optionally, the processor 440 includes one or more general processors that, can be any type of devices capable of processing electronic instructions including CPUs, microprocessors, microcontrollers, host processors, controllers, and ASICs, and so forth. The processor 440 is configured to execute various types of digital storage instructions, such as software or firmware programs, stored in memory that can enable the computing device to provide a wide variety of services.

[0127] Optionally, the augmented reality device 400 according to the embodiments of the present application further includes a memory 460. The memory 460 is electrically connected with the processor 440, and is configured to store program codes required for the processor 440 to run, program codes required for the display 411 to control, and image information emitted by the display 411, and so forth.

[0128] Optionally, the memory 460 can include a volatile memory such as a random access memory (RAM); the memory 460 can also include a non-volatile memory such as a read-only memory (ROM), a flash memory (FM), a hard disk drive (HDD), or a solid-state drive (SSD). The memory 460 can also include a combination of the above-mentioned types of memories.

[0129] In some embodiments, the augmented reality device 400 further includes a carrier 420 for carrying the waveguide module 100, the optical waveguide 10, the protective cover plate 20, and the protective layer 30 are assembled as a whole with the carrier 420.

[0130] Optionally, the carrier 420 can be, but is not limited to, a frame of an augmented reality glasses, a helmet body of an augmented reality helmet, a mask body of an augmented reality mask, and so forth. Optionally, the waveguide module 100 can be disposed on the carrier 420 through an adhesive or a fastening part, and so forth.

[0131] In some embodiments, when the augmented reality device 400 is an augmented reality glasses, the augmented reality device 400 of the embodiments of the present application further comprises a wearing part 430. The wearing part 430 is rotatably connected with the carrying part 420, and the wearing part 430 is used to clamp a wearer (such as a human head, or a head prosthesis, etc.).

[0132] Optionally, the wearing part 430 comprises a first wearing subpart 431 and a second wearing subpart 433. The first wearing subpart 431 is rotatably connected with one end of the carrying part 420, and the second wearing subpart 433 is rotatably connected with the other end of the carrying part 420 away from the first wearing subpart 431. The first wearing subpart 431 and the second wearing subpart 433 are used to clamp the augmented reality device 400 to the wearer. Optionally, the first wearing subpart 431 and the second wearing subpart 433 are also used to set the projection light machine 410. Optionally, the first wearing subpart 431 and the second wearing subpart 433 can be, but are not limited to, the legs of the augmented reality device 400 (AR glasses).

[0133] In the present application, the phrase "embodiment" or "implementation" means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment that is not mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments. In addition, it should be understood that the features, structures or characteristics described in the embodiments of the present application can be combined with each other without contradiction, to form another embodiment of the technical solution of the present application without departing from the spirit and scope of the present application.

[0134] Finally, it should be pointed out that the above implementations are only used to illustrate the technical solutions of the present application and not to limit. Although the present application has been described in detail with reference to the above preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A waveguide module, characterized by, The application relates to a light guide and a protective cover plate. The light guide is used for transmitting an optical signal entering the light guide, and comprises a light transmission layer and a coupling-out grating arranged on a surface of the light transmission layer, wherein the coupling-out grating has an effective window area with a center point. The protective cover plate is arranged in a stack with the light guide and is used for protecting the light guide, and has a first surface facing away from the light guide, wherein the first surface has a normal line, the direction of ambient light incident on the first surface from a side of the protective cover plate facing away from the light guide and deviating from the normal line and the center point is a preset direction, the coupling-out grating further has a central axis passing through the center point and being perpendicular to the effective window area, the protective cover plate comprises a body part and a light adjusting part, the body part is arranged in a stack with the light guide and is spaced apart from the light guide, the light adjusting part is arranged on a side of the body part facing away from the light guide and surrounds an outer periphery of the central axis, the light adjusting part has the first surface, the body part has a second surface facing the light guide, the second surface is a plane, the distance between the first surface and the second surface gradually increases from a position close to the central axis to a position far away from the central axis, and the protective cover plate is used for adjusting the propagation direction of ambient light incident on the protective cover plate from the preset direction, so as to reduce the incident angle of the ambient light from the preset direction and incident on the coupling-out grating. The light adjusting part further has a third surface connected to the first surface by bending, and the third surface is perpendicular to the second surface.

2. The waveguide module of claim 1, wherein, The number of the light adjusting parts is multiple, and the multiple light adjusting parts are arranged around the outer periphery of the central axis.

3. The waveguide module of claim 2, wherein, In the stacking direction of the body part and the light adjusting part, the height h of the light adjusting part ranges from 0.76 microns to 300 microns, and in the direction perpendicular to the central axis, the width w of the light adjusting part ranges from 7.6 microns to 300 microns.

4. The waveguide module of claim 2 or 3, wherein, The h ranges from 1 micron to 80 microns, and the w ranges from 8 microns to 80 microns, or the h ranges from 200 microns to 300 microns, and the w ranges from 200 microns to 300 microns.

5. The waveguide module of claim 4, wherein, The first surface is conical or circular truncated conical, and the angle theta between the first surface and the second surface ranges from 10 degrees to 80 degrees.

6. The waveguide module of claim 2 or 3, wherein, The light guide further comprises a coupling-in grating arranged on a surface of the light transmission layer facing the protective cover plate and spaced apart from the coupling-out grating.

7. The waveguide module of claim 2, wherein, The orthographic projection of the multiple light adjusting parts on the second surface at least covers the orthographic projection of the coupling-out grating on the second surface, and the orthographic projection of the multiple light adjusting parts on the second surface is arranged away from the orthographic projection of the coupling-in grating on the second surface. ​ 8. The waveguide module of claim 2, wherein, The body part further has a fourth surface facing away from the second surface, the fourth surface being flush with an end of the light adjusting part facing away from the body part.

9. The waveguide module of any of claims 1-3, 5, 7-8, wherein, The waveguide module further comprises a protective layer, which is stacked and spaced apart from the light waveguide on a side facing away from the protective cover plate, for protecting the light waveguide.

10. An augmented reality device, characterized by Comprise: A projection light machine, the projection light machine is used for projecting light signal, the light signal includes image information; The waveguide module of any one of claims 1-9, the waveguide module is used for transmitting the light signal, the protective cover plate is farther away from the projection light machine compared with the light waveguide; And A processor, the processor is electrically connected with the projection light machine, for controlling the projection light machine to project the light signal.

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