Cover plate and preparation method thereof, waveguide module and augmented reality equipment

Abstract

The invention provides a cover plate and a preparation method thereof, a waveguide module and augmented reality equipment. The cover plate provided by the embodiment of the invention comprises a body layer, wherein the body layer is provided with a preset surface; the light adjusting layer comprises a plurality of light adjusting parts, the light adjusting parts are randomly distributed on the preset surface, when the incident angle of light on the preset surface is smaller than a preset angle, the light adjusting layer has first light transmittance T1, and when the incident angle of light on the preset surface is larger than the preset angle, the light adjusting layer has second light transmittance T2. The dimming layer has a second light transmittance T2, the plurality of dimming parts are matched so that T1 is larger than or equal to 70% and T2 is smaller than or equal to 20%, and the preset angle ranges from 45 degrees to 75 degrees. When the cover plate is applied to the waveguide module, the rainbow pattern phenomenon of the waveguide module can be effectively improved, and the situation that the normal sight of human eyes is seriously interfered by the rainbow patterns, and visual fatigue is prone to being generated after long-term wearing is better avoided.

Description

Technical Field

[0001] The present application relates to the field of augmented reality technology, and in particular to a cover plate and a preparation method thereof, a waveguide module and an augmented reality device. Background Art

[0002] Augmented Reality (AR) technology can combine virtuality with reality and is now being used more and more widely. Optical waveguides are essential components of augmented reality devices. The outcoupling grating of the optical waveguide is used to deflect the light in the optical waveguide at a certain angle so that the light enters the human eye. When ambient light is incident on the outcoupling grating, if the incident angle of the ambient light is higher than a certain critical angle, the diffraction angle after the outcoupling grating is lower than the total reflection angle, and it will be coupled out into the human eye. Since the ambient light is a mixture of light of different colors, and the wavelengths and diffraction angles of different colors are different, when the ambient light is coupled into the human eye through the outcoupling grating, the light of different colors will enter the human eye at different angles, so the human eye will feel linear or halo-shaped color images, i.e. rainbow patterns, which will seriously interfere with the normal vision of the human eye and cause visual fatigue if worn for a long time. Summary of the invention

[0003] In response to the above problems, an embodiment of the present application provides a cover plate, which, when applied to a waveguide module, can effectively improve the rainbow pattern phenomenon of the waveguide module, and better avoid the rainbow pattern from seriously interfering with the normal vision of the human eye, which can easily cause visual fatigue due to long-term wearing.

[0004] In a first aspect, the present application provides a cover plate, comprising:

[0005] a body layer, the body layer having a predetermined surface; and

[0006] A dimming layer, wherein the dimming layer includes a plurality of dimming parts, wherein the plurality of dimming parts are randomly distributed on the preset surface, and when the incident angle of light on the preset surface is less than a preset angle, the dimming layer has a first transmittance T1, and when the incident angle of light on the preset surface is greater than a preset angle, the dimming layer has a second transmittance T2, and the plurality of dimming parts cooperate to make T1 ≥ 70% and T2 ≤ 20%, wherein the range of the preset angle is 45° to 75°.

[0007] In a second aspect, the present application provides a method for preparing a cover plate, comprising:

[0008] providing a body layer, the body layer having a predetermined surface; and

[0009] A dimming layer is formed on a preset surface of the main layer, the dimming layer includes a plurality of dimming parts, the plurality of dimming parts are randomly distributed on the preset surface, when the incident angle of light on the preset surface is less than a preset angle, the dimming layer has a first transmittance T1, when the incident angle of light on the preset surface is greater than a preset angle, the dimming layer has a second transmittance T2, the plurality of dimming parts cooperate to make T1 ≥ 70% and T2 ≤ 20%, wherein the preset angle ranges from 45° to 75°.

[0010] In a third aspect, the present application provides a waveguide module, comprising:

[0011] an optical waveguide, the optical waveguide being used to transmit an optical signal incident into the optical waveguide; and

[0012] The cover plate described in the first aspect of the present application is stacked and spaced apart from the optical waveguide, so as to protect the optical waveguide.

[0013] In a fourth aspect, the present application provides an augmented reality device, comprising:

[0014] A projection optical machine, the projection optical machine is used to project a light signal, the light signal includes image information;

[0015] The waveguide module according to the third aspect of the present application, wherein the waveguide module is used to transmit the optical signal, and the cover plate is further away from the projection optical machine than the optical waveguide; and

[0016] A processor is electrically connected to the projection optical machine and is used to control the projection optical machine to project the light signal.

[0017] The cover plate of the embodiment of the present application includes a main body layer and a dimming layer, wherein the dimming layer has a first transmittance T1 ≥ 70% for light with an incident angle less than a preset angle, and the dimming layer has a higher transmittance for light with a small angle. When applied to a waveguide module, the dimming layer can have sufficient transmittance to allow viewing of scenes or images in the real world through the cover plate without affecting the normal display effect of the waveguide module; in addition, the dimming layer has a transmittance T2 ≤ 20% for light with an incident angle greater than a preset angle. When applied to a waveguide module, the proportion of large-angle incident light passing through the cover plate to be incident on the outcoupling grating of the waveguide module can be reduced. In other words, the dimming layer can weaken or inhibit large-angle incident light from passing through the cover plate to be incident on the outcoupling grating, thereby better improving the rainbow pattern phenomenon caused by light with large angle incident, better reducing the impact of rainbow patterns on the user's line of sight, preventing the rainbow patterns from blocking the line of sight and preventing eye fatigue caused by long-term use, thereby improving user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 The optical path diagram of light passing through the cover plate and the optical waveguide and being coupled out by the optical waveguide into the human eye.

[0020] Figure 2 It is a schematic structural diagram of a cover plate according to an embodiment of the present application.

[0021] Figure 3 The cover edge of an embodiment of the present application Figure 2 Schematic diagram of the cross-sectional structure in the AA direction.

[0022] Figure 4 Schematic diagram of the light path of light incident on the cover plate of an embodiment of the present application.

[0023] Figure 5 yes Figure 3 Enlarged view of the dashed box I in the middle.

[0024] Figure 6 The cover edge of another embodiment of the present application Figure 2 Schematic diagram of the cross-sectional structure in the AA direction.

[0025] Figure 7 The cover edge of another embodiment of the present application Figure 2 Schematic diagram of the cross-sectional structure in the AA direction.

[0026] Figure 8 It is a schematic diagram of a process for preparing a cover plate according to an embodiment of the present application.

[0027] Fig. 9 1 is a schematic structural diagram of a process for preparing a cover plate according to an embodiment of the present application, wherein (a) is a plan view and (b) is a cross-sectional view.

[0028] Fig.10 It is a schematic diagram of a process for preparing a dimming layer according to an embodiment of the present application.

[0029] Fig.11 It is a schematic flow chart of a method for preparing a dimming layer according to another embodiment of the present application.

[0030] Fig.12 This application adopts Fig.11 A schematic structural diagram of a cover plate obtained by the method for preparing a dimming layer.

[0031] Fig.13It is a schematic diagram of the top view structure of a waveguide module according to an embodiment of the present application.

[0032] Fig.14 The waveguide module of one embodiment of the present application is Fig.13 Schematic diagram of the cross-sectional structure in the BB direction.

[0033] Fig.15 The waveguide module of one embodiment of the present application is Fig.13 Schematic diagram of the cross-sectional structure in the BB direction.

[0034] Fig.16 1 is a schematic diagram of a top view of the optical waveguide according to an embodiment of the present application.

[0035] Fig.17 The waveguide module of another embodiment of the present application is Fig.13 Schematic diagram of the cross-sectional structure in the BB direction.

[0036] Fig.18 The waveguide module of another embodiment of the present application is Fig.13 Schematic diagram of the cross-sectional structure in the BB direction.

[0037] Fig.19 It is a schematic diagram of the three-dimensional structure of an augmented reality device according to an embodiment of the present application.

[0038] Fig. 20 The augmented reality device of an embodiment of the present application is Fig.19 Schematic diagram of the cross-sectional structure in the CC direction.

[0039] Fig.21 It is a circuit block diagram of an augmented reality device according to an embodiment of the present application.

[0040] Description of reference numerals:

[0041] 100-cover plate, 10-main body layer, 11-preset surface, 30-dimming layer, 31-dimming part, 50-filling layer, 70-first anti-glare layer, 90-second anti-glare layer, 10b-anti-fingerprint layer, 11b-second through hole, 20b-mask plate, 21b-first through hole, 200-waveguide module, 210-optical waveguide, 211-light conduction layer, 212-coupling grating, 213-coupling grating, 214-turning grating, 230-protective lens, 250-first adhesive member, 270-second adhesive member, 300-augmented reality device, 310-projection optical machine, 311-display, 313-lens, 320-carrying member, 330-wearing member, 331-first wearing sub-member, 333-second wearing sub-member, 350-processor, 360-memory. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0044] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0045] It should be noted that, for the convenience of explanation, in the embodiments of the present application, the same figure marks represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments.

[0046] At present, the concept of the metaverse is becoming increasingly popular, and related industries are also beginning to develop rapidly. The metaverse provides an immersive experience based on extended reality technology, generates a mirror image of the real world based on digital twin technology, and builds an economic system based on blockchain technology. It closely integrates the virtual world with the real world in the economic system, social system, and identity system, and allows each user to produce content and edit the world. Among them, extended reality technology (XR) is the foundation of the metaverse, including virtual reality technology (VR), AR, and mixed reality technology (MR).

[0047] Augmented reality is a technology that provides users with enhanced perception of reality by superimposing computer-generated image input onto images in the real world and inputting them into the human eye. It is currently being used more and more widely. Optical waveguides are medium devices that guide light waves to propagate in them and are essential components of augmented reality devices. Optical waveguides can transmit light projected by micro-projectors to the front of the glasses, superimposing a virtual image on the real image in front of the human eye, that is, it has the function of augmented reality. Optical waveguides include geometric optical waveguides (also known as reflective array optical waveguides) and diffraction optical waveguides. Compared with geometric optical waveguides, the gratings of diffraction optical waveguides have higher flexibility in design and production, higher mass production and yield, and are therefore more widely used. For example, the diffraction optical waveguide solution for AR glasses is a mainstream technical solution because its optical lenses are thin and light, and its appearance is closer to traditional glasses. At the same time, the implementation method is more convenient and relatively easy to mass produce. Diffraction optical waveguides can be further divided into surface relief gratings and volume holographic gratings.

[0048] The outcoupling grating of the optical waveguide is used to deflect the light in the optical waveguide to a certain angle so that the light can enter the human eye. Figure 1 , when the ambient light (such as sunlight, lighting, ambient stray light, etc.) Figure 1 When the ambient light is incident on the out-coupling grating 213 of the optical waveguide 210 (as shown by the dotted arrow M), if the incident angle of the ambient light is higher than a certain critical angle, the diffraction angle after the out-coupling grating 213 is lower than the total reflection angle, and the ambient light will be coupled out by the out-coupling grating 213 and enter the human eye. Since the ambient light is a mixture of lights of different colors, and the wavelengths of lights of different colors are different, the diffraction angles are different. Therefore, when the ambient light is coupled out by the out-coupling grating 213 and enters the human eye, the lights of different colors will enter the human eye at different angles. Therefore, the wearer will feel a linear or halo-shaped color image, i.e., a rainbow pattern, which will seriously interfere with the normal vision of the human eye. Long-term wearing is prone to visual fatigue and damage to the wearer's eyes. Figure 1 As shown. It can be understood that the outcoupling grating 213 has an effective window. When ambient light is incident on the effective window of the augmented reality device (AR device), when the incident angle is greater than the critical angle, a bright line or bright band will be generated in the effective window of the augmented reality device. This phenomenon is called the rainbow pattern phenomenon. Rainbow patterns cannot be eradicated from the perspective of physical principles. That is, the optical waveguide has an outcoupling grating 213, and there are rainbow patterns caused by the outcoupling grating 213. The rainbow pattern phenomenon will cause the AR display device experience to deteriorate. At present, there is no better way in the industry to eliminate or suppress the diffraction optical waveguide rainbow pattern.

[0049] The "critical angle" in this application refers to the critical angle at which 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 when the incident angle is higher than the critical angle. That is, the critical angle at which the ambient light incident on the out-coupling grating produces rainbow patterns. The critical angle is related to the total reflection angle of the light in the optical waveguide, the period of the out-coupling grating, and the refractive index of the optical waveguide.

[0050] The improvement or suppression of rainbow patterns can be achieved through the grating design of the optical waveguide, which can suppress the diffraction efficiency of the grating for large-angle incident light (i.e. light with a large incident angle), thereby reducing the rainbow patterns. However, the illumination of outdoor sunlight is usually around 10 4 The unit is lux. To the human eye, reducing the rainbow pattern from tens of thousands of nits to 10,000 or 20,000 nits does not make any essential difference, so the effect of the grating on suppressing the rainbow pattern is very limited.

[0051] See also Figure 2 and Figure 3 The embodiment of the present application provides a cover plate 100, which includes a main body layer 10 and a dimming layer 30, wherein the main body layer 10 has a preset surface 11, and the dimming layer 30 includes a plurality of dimming parts 31, wherein the plurality of dimming parts 31 are randomly distributed on the preset surface 11, and when the incident angle of light on the preset surface 11 is less than a preset angle, the dimming layer 30 has a first transmittance T1, and when the incident angle of light on the preset surface 11 is greater than a preset angle, the dimming layer 30 has a second transmittance T2, and the plurality of dimming parts 31 cooperate to make T1 ≥ 70% and T2 ≤ 20%, wherein the preset angle ranges from 45° to 75°.

[0052] The cover plate 100 of the embodiment of the present application can be applied to an augmented reality device, used as an outer protective lens of an optical waveguide in a waveguide module of the augmented reality device, and used to improve (or weaken, or suppress) the rainbow pattern phenomenon of the optical waveguide. When the cover plate 100 is applied to the waveguide module, the cover plate 100 serves as an outer protective lens of the waveguide module, that is, the cover plate 100 is farther away from the human eye than the optical waveguide.

[0053] The “light” in the embodiment of the present application refers to light incident from the outside of the cover plate 100, such as visible light such as sunlight, lamplight, ambient stray light, etc.

[0054] In the embodiments of the present application, when a numerical value range from a to b is involved, unless otherwise specified, it means that the numerical value can be any numerical value between a and b, including the endpoint numerical value a and the endpoint numerical value b.

[0055] Optionally, the incident angle of the light on the preset surface 11 refers to the angle between the incident light and a normal line perpendicular to the preset surface 11 .

[0056] The plurality of dimming parts 31 are randomly distributed on the preset surface 11 . It can be understood that the plurality of dimming parts 31 are distributed on the preset surface 11 at intervals, and the plurality of dimming parts 31 are randomly distributed.

[0057] It can be understood that the random distribution of the multiple dimming parts 31 may include at least one of the random distribution of the gap between any two adjacent dimming parts 31 among the multiple dimming parts 31, the random distribution of the maximum width of the positive projection of the dimming part 31 on the preset surface 11, and the random distribution of the maximum height of the dimming part 31.

[0058] It can be understood that the main layer 10 is used to support the dimming layer 30 , and the dimming layer 30 can be formed on the surface of the main layer 10 .

[0059] Optionally, the first light transmittance T1 may be, but is not limited to, 70%, 73%, 75%, 78%, 80%, 83%, 85%, 88%, 90%, 92%, 94%, 96%, 98%, 99%, etc. The higher the first light transmittance, the higher the transmittance of incident light at a small angle (referring to light with an incident angle less than a preset angle). When the cover plate 100 is applied to a waveguide module, the scene of the real world can be better seen through the cover plate 100.

[0060] Furthermore, the first light transmittance T1 is ≥ 80%. Still further, the first light transmittance T1 is ≥ 90%.

[0061] Optionally, the second transmittance T2 may be, but is not limited to, 20%, 18%, 16%, 14%, 12%, 10%, 8%, 6%, 4%, 2%, 1%, 0%, etc. The lower the second transmittance, the lower the transmittance of incident light at a large angle (referring to light with an incident angle greater than a preset angle). When the cover plate 100 is applied to a waveguide module, it is possible to better reduce the large-angle incident angle from passing through the cover plate 100 and irradiating the outcoupling grating, thereby better improving or suppressing the generation of rainbow patterns.

[0062] Furthermore, the second light transmittance T2 is ≤10%. Still further, the second light transmittance T2 is ≤5%.

[0063] Optionally, the preset angle may be, but is not limited to, 45°, 48°, 50°, 52°, 55°, 58°, 60°, 62°, 65°, 68°, 70°, 72°, 75°, etc. The preset angle is related to the total reflection angle of the light in the optical waveguide, the period of the outcoupling grating, and the refractive index of the optical waveguide. The preset angle is related to the critical angle of rainbow pattern after the light is incident on the outcoupling grating. Optionally, the difference between the preset angle and the critical angle is less than 10° or less than 5°. The closer the preset angle is to the critical angle for generating rainbow pattern, the better the effect of eliminating or suppressing rainbow pattern by the cover plate 100. When the preset angle is equal to the critical angle for generating rainbow pattern, the proportion of light greater than the preset angle passing through the cover plate 100 is very small, thereby greatly reducing the generation of rainbow pattern.

[0064] The cover plate 100 of the embodiment of the present application includes a main body layer 10 and a dimming layer 30, wherein the dimming layer 30 has a first transmittance T1 ≥ 70% for light with an incident angle less than a preset angle, and the dimming layer 30 has a higher transmittance for incident light at a small angle. When applied to a waveguide module, the dimming layer 30 can have sufficient transmittance to allow viewing of scenes or images in the real world through the cover plate 100 without affecting the normal display effect of the waveguide module; in addition, the dimming layer 30 has a transmittance T2 ≤ 20% for light with an incident angle greater than a preset angle. When applied to a waveguide module, the proportion of large-angle incident light passing through the cover plate 100 to be incident on the outcoupling grating of the waveguide module can be reduced. In other words, the dimming layer 30 can weaken or inhibit large-angle incident light from passing through the cover plate 100 to be incident on the outcoupling grating, thereby better improving the rainbow pattern phenomenon generated by light with large-angle incident angle, better reducing the impact of rainbow patterns on the user's line of sight, preventing the rainbow patterns from blocking the line of sight and eye fatigue caused by long-term use, and improving the user experience.

[0065] Optionally, the body layer 10 is light-transmissive, and the light transmittance of the body layer 10 is greater than or equal to 80%. Further, the light transmittance of the body layer 10 is greater than or equal to 90%. Specifically, the light transmittance of the body layer 10 can be, but is not limited to, 80%, 82%, 85%, 88%, 90%, 92%, 95%, 98%, 99%, etc.

[0066] Optionally, the material of the body layer 10 may be at least one of glass material and resin material. The resin material may be but is not limited to at least one of polyethylene terephthalate (PET for short), polycarbonate (PC for short), and the like.

[0067] Optionally, the thickness of the body layer 10 may be 0.3 mm to 1 mm; specifically, it may be, but not limited to, 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, etc. If the body layer 10 is too thin, it will not provide sufficient protection for the optical waveguide; if the body layer 10 is too thick, the thickness of the waveguide module will be increased, which is not conducive to the thinness of the waveguide module.

[0068] Optionally, the dimming unit 31 has light absorbing properties or light absorbing effects. Optionally, the light absorbing material can be a dark material with light absorbing properties such as black or gray. Figure 4 As shown, when the cover plate 100 is applied to the waveguide module, the plurality of dimming parts 31 are arranged at intervals, and for light with an incident angle less than a preset angle (such as Figure 4 The dotted arrow P) passes through the dimming layer 30 and the main layer 10 from the gaps between the multiple dimming parts 31, and then passes through the cover plate 100 and is incident on the optical waveguide, so that the waveguide module can normally see the scene of the real world without affecting the original function of the waveguide module; for light with an incident angle greater than the preset angle (such as Figure 4 The dotted arrow Q) will be absorbed by the dimming unit 31 and will have difficulty passing through the dimming layer 30 to enter the outcoupling grating of the optical waveguide, thereby greatly reducing the proportion of the outcoupling grating of the optical waveguide that passes through the cover plate 100 at a large incident angle, and greatly improving the rainbow pattern phenomenon of the waveguide module. It can be understood that the cover plate 100 can filter out the incident light at a large angle, thereby eliminating the rainbow pattern phenomenon, improving the display effect of the waveguide module using the cover plate 100, and improving the user experience.

[0069] Optionally, the random distribution degree of the plurality of dimming units 31 is k, and the range of the random distribution degree k is: k≥10%.

[0070] It should be noted that the range of the random degree k of the random distribution of the multiple dimming parts 31 is: k≥10%, which can be: the random degree of the gap between any two adjacent dimming parts 31 among the multiple dimming parts 31 is greater than or equal to 10%, the random degree of the maximum width of the positive projection of the dimming part 31 on the preset surface 11 is greater than or equal to 10%, and the random degree of the maximum height of the dimming part 31 is greater than or equal to 10%. At least one of the above.

[0071] Specifically, the random degree k may be, but is not limited to, 10%, 12%, 15%, 17%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, etc. When the random degree k of the arrangement of the plurality of dimming parts 31 is too small, there is a strong diffraction, which may cause the human eye to produce double images when observing the real scene after the cover plate 100 is applied to the augmented reality device. For example, when wearing glasses with the cover plate 100 to observe the lamp tube, multiple lamp tube double images will appear, which seriously affects the user experience; the higher the random degree of the arrangement of the plurality of dimming parts 31 on the body layer 10, the smaller the diffraction phenomenon of the cover plate 100, and when the cover plate 100 is applied to the augmented reality device, the augmented reality device is less likely to produce double images.

[0072] The "randomness" of the embodiment of the present application is generated by calling the Rand function in Matlab software.

[0073] See also Figure 5 , optionally, the maximum height of each dimming section 31 is h, and the maximum width of the orthographic projection of the dimming section 31 on the preset surface 11 is d, wherein 0.1≤h / d≤20. It can be understood that the ratio between the maximum height of the dimming section 31 and the maximum width of the orthographic projection of the dimming section 31 on the preset surface 11 ranges from 0.1 to 20. Specifically, the ratio between the maximum height of the dimming section 31 and the maximum width of the orthographic projection of the dimming section 31 on the preset surface 11 can be, but is not limited to, 0.1, 0.3, 0.5, 0.7, 1, 1.5, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, etc. If the ratio of h / d is too small, the absorption effect on incident light at a large angle will be weak. When the cover plate 100 is applied to a waveguide module, it will not be conducive to improving the rainbow pattern phenomenon of the optical waveguide. If the ratio of h / d is too large, the difficulty of the preparation process of the dimming part 31 will be increased, and it will be difficult to maintain a straight state.

[0074] It should be noted that the maximum height h of each dimming section 31 refers to the vertical distance between the point on the dimming section 31 that is farthest from the preset surface 11 and the preset surface 11. The maximum width d of the orthographic projection of the dimming section 31 on the preset surface 11 refers to the distance between the two farthest points on the area surrounded by the orthographic projection of the dimming section 31 on the preset surface 11.

[0075] Furthermore, the range of the ratio between the maximum height h of the dimming part 31 and the maximum width d of the orthographic projection of the dimming part 31 on the preset surface 11 is: 1≤h / d≤5. When the range of h / d is 1 to 5, the multiple dimming parts 31 can cooperate to have a better absorption effect on incident light at a large angle. When the cover plate 100 is applied to a waveguide module, the rainbow pattern phenomenon of the optical waveguide can be better improved, and it is easier to prepare, which reduces the process difficulty of preparing the dimming part 31.

[0076] Optionally, the maximum width d of the orthographic projection of each dimming unit 31 on the preset surface 11 is in the range of 1um≤d≤200um. Specifically, the maximum width d of the orthographic projection of the dimming unit 31 on the preset surface 11 may be, but is not limited to, 1um, 3um, 5um, 7um, 10um, 20um, 25um, 30um, 35um, 40um, 45um, 50um, 55um, 60um, 70um, 80um, 90um, 100um, 120um, 140um, 160um, 180um, 200um, etc. If the maximum width d of the orthographic projection of the dimming part 31 on the preset surface 11 is too small, the absorption effect on incident light at a large angle (i.e., incident light greater than the preset angle) is weak. When the cover 100 is applied to a waveguide module, it is not conducive to improving the rainbow pattern phenomenon of the optical waveguide. If the maximum width d of the orthographic projection of the dimming part 31 on the preset surface 11 is too large, the dimming part 31 (i.e., a black spot) is easily visible on the appearance of the cover 100, affecting the visual effect of the appearance of the cover 100.

[0077] Furthermore, the maximum width d of the orthographic projection of the dimming part 31 on the preset surface 11 is in the range of 20um≤d≤100um. When the maximum width d of the orthographic projection of the dimming part 31 on the preset surface 11 is in the range of 20um to 100um, the cooperation of the multiple dimming parts 31 can have a better absorption effect on incident light at a large angle. When the cover plate 100 is applied to a waveguide module, the rainbow pattern phenomenon of the optical waveguide can be better improved. In addition, the dimming part 31 is not easy to be seen, and has a better appearance effect.

[0078] Optionally, the maximum widths d of the orthographic projections of the plurality of dimming parts 31 on the preset surface 11 are unequal, and the maximum widths d of the orthographic projections of the dimming parts 31 on the preset surface 11 are randomly distributed between 1 μm and 200 μm. The degree of random distribution of the maximum widths d of the orthographic projections of the dimming parts 31 on the preset surface 11 is greater than or equal to 10%.

[0079] Optionally, the maximum height h of the dimming unit 31 is in the range of 1um≤h≤200um. Specifically, the maximum height h of the dimming unit 31 may be, but is not limited to, 1um, 3um, 5um, 7um, 10um, 15um, 20um, 25um, 30um, 35um, 40um, 45um, 50um, 60um, 70um, 80um, 90um, 100um, 110um, 120um, 130um, 140um, 150um, 160um, 180um, 200um, etc. If the maximum height h of the dimming portion 31 is too short, the absorption effect on incident light at a large angle (i.e., incident light greater than a preset angle) is weak, and when the cover plate 100 is applied to a waveguide module, it is not conducive to improving the rainbow pattern phenomenon of the optical waveguide; if the maximum height h of the dimming portion 31 is too high, the dimming portion 31 (i.e., a black spot) is easily visible on the appearance of the cover plate 100, affecting the visual effect of the appearance of the cover plate 100, and making the cover plate 100 thicker, which is not conducive to the thinness of the cover plate 100.

[0080] Furthermore, the maximum height h of the dimming section 31 is in the range of 50um≤h≤150um. When the maximum height h of the dimming section 31 is in the range of 50um to 150um, the multiple dimming sections 31 can cooperate to have a better absorption effect on incident light at a large angle. When the cover plate 100 is applied to a waveguide module, the rainbow pattern phenomenon of the optical waveguide can be better improved. In addition, the dimming section 31 is not easy to be seen, which has a better appearance effect, and the cover plate 100 has a lighter weight and a thinner thickness.

[0081] Optionally, the maximum heights h of the plurality of dimming parts 31 are unequal, and the maximum heights h of the dimming parts 31 are randomly distributed between 1 μm and 200 μm. The degree of random distribution of the maximum heights h of the plurality of dimming parts 31 is greater than or equal to 10%.

[0082] Optionally, the range of the minimum gap s between any two adjacent dimming parts 31 is: 0.1um≤s≤1000um. In other words, the range of the minimum gap s between any two adjacent dimming parts 31 is: 0.1um≤s≤1mm. Specifically, the minimum gap s between any two adjacent dimming parts 31 can be, but is not limited to, 0.1um, 0.3um, 0.5um, 0.8um, 1um, 3um, 5um, 7um, 10um, 15um, 20um, 25um, 30um, 35um, 40um, 45um, 50um, 60um, 80um, 100um, 120um, 140um, 160um, 180um, 200um, 300um, 400um, 500um, 600um, 700um, 800um, 900um, 1000um, etc. If the minimum gap s between any two adjacent dimming parts 31 is too small, the light transmittance of this part will be seriously reduced, and even obvious black spots can be seen. When applied to a waveguide module, the effect of the waveguide module in viewing the real scene is affected; if the minimum gap s between any two adjacent dimming parts 31 is too large, the area between the adjacent dimming parts 31 is too large, and some areas do not have the function of filtering large-angle incident light. When applied to a waveguide module, rainbow patterns appear in some areas of the waveguide module, affecting the display effect of the waveguide module.

[0083] It can be understood that the minimum gap s between any two adjacent dimming parts 31 is not equal, and the minimum gap s between any two adjacent dimming parts 31 is randomly distributed between 0.1um and 1000μm. The random degree of random distribution of the minimum gap s between any two adjacent dimming parts 31 is greater than or equal to 10%.

[0084] In some embodiments, the color of the dimming unit 31 is black. The material of the dimming unit 31 is ink.

[0085] In other embodiments, the dimming unit 31 includes ink and magnetic particles, and the magnetic particles are dispersed in the ink. Magnetic particles are added to the dimming unit 31, so that the dimming unit 31 can be highly absorbed by applying a magnetic field, and a dimming unit 31 with a higher aspect ratio (i.e., a higher h / d) can be prepared, so that multiple dimming units 31 can cooperate to have a better absorption effect on incident light at a large angle. When the cover plate 100 is applied to a waveguide module, the rainbow pattern phenomenon of the optical waveguide can be better improved, and it is easier to prepare, reducing the process difficulty of preparing the dimming unit 31.

[0086] Optionally, the mass fraction w% of the magnetic particles in the dimming section 31 is in the range of 20%≤w%≤50%. Specifically, the mass fraction w% of the magnetic particles in the dimming section 31 may be, but is not limited to, 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc. If the content of the magnetic particles in the dimming section 31 is too little, it is difficult to increase the height of the dimming section 31 by applying a magnetic field; if the content of the magnetic particles in the dimming section 31 is too much, the solid content of the raw material for preparing the dimming section 31 is too high, which affects the fluidity of the raw material for preparing the dimming section 31, and thus it is difficult to increase the height of the dimming section 31.

[0087] Optionally, the particle size of the magnetic particles is nanometer-scale, and the particle size of the magnetic particles ranges from 5nm to 300nm. Optionally, the particle size of the magnetic particles can be, but is not limited to, 5nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 80nm, 100nm, 120nm, 140nm, 160nm, 180nm, 200nm, 220nm, 240nm, 260nm, 280nm, 300nm, etc. The smaller the particle size of the magnetic particles, the more magnetic particles can be dispersed in each dimming unit 31, which is more conducive to making the height of the dimming unit 31 higher and the smoothness of the surface of the dimming unit 31; if the particle size of the magnetic particles is too large and is closer to the size of the dimming unit 31, the shape of the dimming unit 31 is affected, and the appearance of the cover 100 is affected.

[0088] Optionally, the magnetic particles may be, but are not limited to, at least one of nano iron powder and nano magnetic powder.

[0089] Optionally, the shape of the dimming unit 31 may be at least one of a hemispherical shape, a hemispherical shape, a rectangular parallelepiped, a cube, a prism, and the like.

[0090] See also Figure 6 In some embodiments, the cover plate 100 further includes a filling layer 50, which fills the gaps between the plurality of dimming parts 31 and covers the surface of the dimming part 31 facing away from the main layer 10, and the filling layer 50 is light-transmissive.

[0091] It can be understood that the filling layer 50 covers the portion of the preset surface 11 exposed from the dimming layer 30 and the surface of the dimming unit 31 .

[0092] It can be understood that the plurality of dimming parts 31 are embedded in the filling layer 50 .

[0093] Since the dimming part 31 is a micron-level structure, it is easily worn or damaged during use, so that the filtering effect of the cover plate 100 on incident light greater than a preset angle is weakened or even disappears, so that the cover plate 100 is applied to the waveguide module, which affects the cover plate 100's suppression and improvement effect on the rainbow pattern of the waveguide module. In this embodiment, a filling layer 50 is provided on the surface of the dimming part 31, which can better prevent the dimming part 31 from being worn or damaged during use, so that the cover plate 100 has a longer service life and improves the stability and reliability of the dimming part 31.

[0094] Optionally, the thickness of the filling layer 50 is greater than or equal to the maximum height of the dimming unit 31 , which can better protect the dimming unit 31 and prevent the dimming unit 31 from being worn or damaged during use.

[0095] Optionally, the light transmittance T3 of the filling layer 50 is in the range of: T3 ≥ 80%. Further, the light transmittance T3 of the filling layer 50 is ≥ 90%. Specifically, the light transmittance T3 of the filling layer 50 may be, but is not limited to, 80%, 83%, 85%, 88%, 90%, 92%, 94%, 96%, 98%, 99%, etc. The higher the light transmittance of the filling layer 50, the higher the transmittance of the incident light with an incident angle less than a preset angle. When the cover plate 100 is applied to the waveguide module, the scene of the real world can be better seen through the cover plate 100.

[0096] Optionally, the light transmittance T3 of the filling layer 50 is equal to the light transmittance of the main layer 10, so that the filling layer 50 and the main layer 10 can be better integrated from a visual perspective and have a better appearance.

[0097] See also Figure 7 In some embodiments, the cover plate 100 further includes a first anti-glare layer 70 and a second anti-glare layer 90, wherein the first anti-glare layer 70 is disposed on the surface of the filling layer 50 away from the main body layer 10; and the second anti-glare layer 90 is disposed on the surface of the main body away from the dimming layer 30. The first anti-glare layer 70 and the second anti-glare layer 90 are used to prevent glare caused by reflection from the interface between the cover plate 100 and the air. In other words, the first anti-glare layer 70 and the second anti-glare layer 90 are used to prevent glare caused by surface reflection of the cover plate 100.

[0098] Optionally, the first anti-glare layer 70 may include but is not limited to at least one of magnesium fluoride, titanium oxide, lead sulfide, lead selenide, a ceramic infrared light infrared anti-reflection film, a vinyl silsesquioxane hybrid film, and the like.

[0099] Optionally, the second anti-glare layer 90 may include but is not limited to at least one of magnesium fluoride, titanium oxide, lead sulfide, lead selenide, a ceramic infrared light infrared anti-reflection film, a vinyl silsesquioxane hybrid film, and the like.

[0100] The cover plate 100 of the embodiment of the present application can be prepared by the method described in the following embodiments of the present application. In addition, it can also be prepared by other methods. The preparation method of the embodiment of the present application is only one or more preparation methods of the cover plate 100 of the present application and should not be understood as a limitation on the cover plate 100 provided by the embodiment of the present application.

[0101] See also Figure 8 and Fig. 9 The present embodiment also provides a method for preparing a cover plate 100, which includes:

[0102] S201, providing a body layer 10, wherein the body layer 10 has a preset surface 11; and

[0103] S202, forming a dimming layer 30 on the preset surface 11 of the main layer 10, the dimming layer 30 includes a plurality of dimming parts 31, the plurality of dimming parts 31 are randomly distributed on the preset surface 11, when the incident angle of light on the preset surface 11 is less than the preset angle, the dimming layer 30 has a first transmittance T1, when the incident angle of light on the preset surface 11 is greater than the preset angle, the dimming layer 30 has a second transmittance T2, the plurality of dimming parts 31 cooperate to make T1 ≥ 70% and T2 ≤ 20%, wherein the range of the preset angle is 45° to 75°.

[0104] For detailed descriptions of the main layer 10 , the dimming layer 30 , the dimming unit 31 , etc., please refer to the descriptions of the corresponding parts in the above embodiments, which will not be repeated here.

[0105] The cover plate 100 prepared by the preparation method of the cover plate 100 of the embodiment of the present application includes a main body layer 10 and a dimming layer 30, wherein the dimming layer 30 has a first transmittance T1 ≥ 70% for light with an incident angle less than a preset angle, and the dimming layer 30 has a higher transmittance for incident light at a small angle. When applied to a waveguide module, the dimming layer 30 can have sufficient transmittance to allow viewing of scenes or images in the real world through the cover plate 100 without affecting the normal display effect of the waveguide module; in addition, the dimming layer 30 has a transmittance T2 ≤ 20% for light with an incident angle greater than a preset angle. When applied to a waveguide module, the proportion of large-angle incident light passing through the cover plate 100 to be incident on the outcoupling grating of the waveguide module can be reduced. In other words, the dimming layer 30 can weaken or inhibit large-angle incident light from passing through the cover plate 100 to be incident on the outcoupling grating, thereby better improving the rainbow pattern phenomenon caused by large-angle incident light, and better avoiding the rainbow pattern from interfering with the normal vision of the human eye, which is prone to visual fatigue after long-term wearing.

[0106] Please also see Fig.10In some embodiments, the dimming layer 30 is formed on the predetermined surface 11 of the body layer 10, including:

[0107] S2021, forming an anti-fingerprint layer 10b on the predetermined surface 11 of the body layer 10;

[0108] Optionally, one or more materials with strong hydrophobicity such as perfluoropolyether and perfluoropolyether derivatives are coated with an anti-fingerprint layer 10 b on the predetermined surface 11 of the body layer 10 .

[0109] S2022, providing a mask plate 20b, and stacking the mask plate 20b on a surface of the anti-fingerprint layer 10b away from the main layer 10, wherein the mask plate 20b has a plurality of randomly distributed first through holes 21b;

[0110] Optionally, the method for preparing the mask plate 20b includes:

[0111] 1) designing a distribution drawing of a plurality of first through holes 21 b according to the random distribution of the dimming unit 31 ; and

[0112] 2) Providing a film material, and according to the distribution drawing, punching a plurality of first through holes 21b on the film material to obtain the mask plate 20b.

[0113] Optionally, according to the distribution drawing, a plurality of first through holes 21 b are punched on the film material by laser punching.

[0114] It should be noted that the random distribution of the plurality of first through holes 21 b may include at least one of a random distribution of the maximum widths of the first through holes 21 b and a random distribution of the intervals between any adjacent first through holes 21 b.

[0115] It can be understood that the mask plate 20b includes a plurality of randomly distributed first through holes 21b, so the portions of the anti-fingerprint layer 10b corresponding to the plurality of first through holes 21b are exposed. In other words, the portions of the anti-fingerprint layer 10b overlapping the plurality of first through holes 21b are exposed.

[0116] S2023, removing the portion of the anti-fingerprint layer 10b that overlaps with the plurality of first through holes 21b, so that a plurality of second through holes 11b that are randomly distributed are formed on the anti-fingerprint layer 10b, and removing the mask plate 20b;

[0117] Optionally, plasma bombardment is performed to remove the portion of the anti-fingerprint layer 10b exposed to the plurality of first through holes 21b, and to form a plurality of randomly distributed second through holes 11b on the anti-fingerprint layer 10b.

[0118] It can be understood that the orthographic projection of the first through hole 21 b on the preset surface 11 overlaps with the orthographic projection of the second through hole 11 b on the preset surface 11 .

[0119] S2024, coating a slurry on a surface of the anti-fingerprint layer 10 b away from the body layer 10 to form a plurality of randomly distributed droplets in the plurality of second through holes 11 b; and

[0120] Optionally, the slurry is a slurry composed of raw material components for forming the dimming unit 31. Optionally, the slurry includes a solvent, a resin, and carbon powder.

[0121] It can be understood that when the slurry is applied on the surface of the ink layer away from the body layer 10, the droplets will be distributed in the area without the anti-fingerprint layer 10b, that is, the area of ​​the second through hole 11b of the anti-fingerprint layer 10b. Because the surface energy of the body layer 10 exposed by the second through hole 11b is higher, and the surface energy outside the second through hole 11b of the anti-fingerprint layer 10b is lower, the slurry applied by scraping will converge to the area with high surface energy under the action of surface tension, so that the droplets are distributed on the surface of the body layer 10 without the anti-fingerprint layer 10b, that is, the position of the second through hole 11b of the anti-fingerprint layer 10b.

[0122] S2025 , solidifying the plurality of liquid droplets to form a dimming layer 30 , wherein the dimming layer 30 includes a plurality of dimming units 31 .

[0123] Optionally, the plurality of droplets are heated and solidified to form a dimming layer 30, wherein the dimming layer 30 includes a plurality of dimming parts 31. Cutting is performed to obtain a cover plate 100 of a target size.

[0124] In some embodiments, the dimming layer 30 can be formed by nanoimprinting, that is, a layer of glue is first applied, and then a nanoimprint mold is used to imprint on the glue to form a dimming part 31. However, the dimming layer 30 prepared by this method has a layer of base glue, and the base glue also has light absorption properties, which further reduces the overall light transmittance of the cover plate 100, that is, the light transmittance at small angles is also reduced. When applied to a waveguide module, it affects the display effect of the waveguide module. In addition, using the nanoimprint process, the nanoimprint mold needs to be prepared by electron beam exposure and etching process, which is very expensive and has a very long processing cycle, so the time cost and cost cost are very high. In actual production, dedicated nanoimprint equipment is required, and the production efficiency of the nanoimprint equipment is relatively slow. Therefore, if large-scale mass production is to be achieved, more nanoimprint equipment needs to be invested, and the equipment investment is huge.

[0125] Compared with the scheme of forming the dimming layer 30 by nanoimprinting, the dimming layer 30 is prepared by the method of this embodiment, and there is no problem of primer. When applied to the waveguide module, it will not affect the transmittance of incident light at a small angle, so that the display effect of the waveguide module is less affected, so that the waveguide module has a better display effect. In addition, compared with the scheme of nanoimprinting, the preparation of the scheme of this embodiment does not need to use processes such as electron beam exposure and etching to make nanoimprint molds, nor does it need to invest in more nanoimprinting equipment, so it can greatly reduce the production cost of the cover plate 100 and shorten the production cycle of the cover plate 100.

[0126] See also Fig.11 and Fig.12 In some other embodiments, the dimming layer 30 is formed on the predetermined surface 11 of the main layer 10, including:

[0127] S2021a, forming an anti-fingerprint layer 10b on the predetermined surface 11 of the body layer 10;

[0128] S2022a, providing a mask plate 20b, and stacking the mask plate 20b on a surface of the anti-fingerprint layer 10b away from the main layer 10, wherein the mask plate 20b has a plurality of randomly distributed first through holes 21b;

[0129] S2023a, removing the portion of the anti-fingerprint layer 10b that overlaps with the plurality of first through holes 21b, so that a plurality of second through holes 11b that are randomly distributed are formed on the anti-fingerprint layer 10b, and removing the mask plate 20b;

[0130] For a detailed description of S2021a to S2024a, please refer to the description of the corresponding parts of the above embodiments, which will not be repeated here.

[0131] S2024a, coating a slurry on a surface of the anti-fingerprint layer 10b away from the body layer 10 to form a plurality of randomly distributed droplets in the plurality of second through holes 11b, wherein the slurry is a magnetic slurry;

[0132] It is understandable that the slurry has magnetic properties or the property of being attracted by magnets. It is also understandable that the slurry is a magnetic fluid.

[0133] Optionally, the slurry includes solvent, resin, carbon powder and magnetic particles.

[0134] S2025a, applying a magnetic field to raise the height of the plurality of droplets; and

[0135] Optionally, the product is placed in a unidirectional magnetic field. At this time, the magnetic fluid or the liquid droplets will also be attracted by the magnetic field to elongate the droplets, so that the dimming part 31 obtained after curing can have a larger aspect ratio. When applied to a waveguide module, the rainbow pattern of the waveguide module can be better improved.

[0136] S2026a, solidifying the plurality of liquid droplets to form a dimming layer 30 , wherein the dimming layer 30 includes a plurality of dimming parts 31 .

[0137] The cover plate 100 prepared in this embodiment is as follows Fig.12 shown.

[0138] For a detailed description of S2026a, please refer to the description of the corresponding part of the above embodiment, which will not be repeated here.

[0139] Compared with the solution of using non-magnetic slurry to prepare the dimming part 31, the solution of using magnetic slurry to prepare the dimming part 31 in this embodiment can improve the aspect ratio of the obtained dimming part 31 (ie, the value of h / d), thereby improving the improvement effect of rainbow lines.

[0140] Optionally, when the cover plate 100 further includes a filling layer 50 , the method of the embodiment of the present application further includes: removing the anti-fingerprint layer 10 b , and forming the filling layer 50 on the surface of the body layer 10 having the plurality of dimming units 31 .

[0141] Optionally, when the cover plate 100 further includes a first anti-glare layer 70 and a second anti-glare layer 90 , the method of the embodiment of the present application further includes: forming the first anti-glare layer 70 on the surface of the filling layer 50 away from the main layer, and forming the second anti-glare layer 90 on the surface of the main layer 10 away from the filling layer 50 .

[0142] See also Figures 13 to 15 The embodiment of the present application further provides a waveguide module 200, which includes an optical waveguide 210 and the cover plate 100 described in the embodiment of the present application. The optical waveguide 210 is used to transmit the optical signal injected into the optical waveguide 210; the cover plate 100 is stacked and spaced apart from the optical waveguide 210 to protect the optical waveguide 210, so as to improve the drop resistance and scratch resistance of the optical waveguide 210.

[0143] The waveguide module 200 of the embodiment of the present application can be applied to an augmented reality device. The augmented reality device of the embodiment of the present application can be, but is not limited to, a near-eye display system such as augmented reality glasses, an augmented reality helmet, and an augmented reality mask.

[0144] It should be noted that the cover plate 100 in the embodiment of the present application serves as an outer protective lens or outer protective lens of the optical waveguide 210, and the cover plate 100 is farther away from the wearer than the optical waveguide 210. It can also be understood that the light is incident from the side of the cover plate 100 away from the optical waveguide 210.

[0145] Alternatively, if Fig.14 As shown, the dimming layer 30 is closer to the optical waveguide 210 than the main layer 10, or, as shown Fig.15 As shown, the dimming layer 30 is further away from the optical waveguide 210 than the main layer 10. In other words, the dimming layer 30 can be arranged on the side of the main layer 10 facing the optical waveguide 210, or can be arranged on the side of the base layer away from the optical waveguide 210. When the dimming layer 30 is arranged on the side of the main layer 10 facing the optical waveguide 210, the dimming layer 30 can be better prevented from being worn during use, and the service life of the cover plate 100 can be better improved.

[0146] For detailed description of other aspects such as the cover plate 100 and the dimming layer 30 , please refer to the description of the corresponding parts of the above embodiments, which will not be repeated here.

[0147] The optical waveguide 210 also includes a light conductive layer 211, a coupling-in grating 212 and a coupling-out grating 213. The coupling-in grating 212 and the coupling-out grating 213 are arranged at intervals on the surface of the light conductive layer 211 facing the cover plate 100; the coupling-in grating 212 is used to couple the optical signal into the light conductive layer 211; the light conductive layer 211 is used to transmit the optical signal entering the light conductive layer 211; the coupling-out grating 213 is used to couple the optical signal transmitted through the light conductive layer 211 out of the optical waveguide 210.

[0148] It can be understood that the coupling-in grating 212 can deflect the incident light signal (i.e., light) of the projection optical machine of the augmented reality device by a certain angle using the grating diffraction effect, thereby satisfying the total reflection condition in the light transmission layer 211, so that the light signal is continuously totally reflected in the light transmission layer 211, thereby realizing the transmission of the light signal. When the light signal is transmitted to the coupling-out grating 213, the coupling-out grating 213 again deflects the light signal by a certain angle to couple out the optical waveguide 210, forming an image that enters the wearer's eyes.

[0149] Optionally, the coupling-in grating 212 may be, but not limited to, one of a binary grating, a tilted grating, a blazed grating, a two-dimensional grating, etc. The coupling-out grating 213 may be, but not limited to, one of a binary grating, a tilted grating, a blazed grating, a two-dimensional grating, etc. The coupling-in grating 212 and the coupling-out grating 213 may be of the same type or different types.

[0150] See also Fig.16In some other embodiments, the optical waveguide 210 further includes a turning grating 214, and the turning grating 214 is used to expand the pupil of the image information in the optical signal. The turning grating 214, the coupling-in grating 212, and the coupling-out grating 213 are respectively arranged at intervals on the surface of the optical transmission layer 211 away from the cover plate 100. When the optical waveguide 210 further includes the turning grating 214, the optical signal coupled into the optical transmission layer 211 through the coupling-in grating 212 is firstly expanded through the turning grating 214, and then coupled out of the optical waveguide 210 through the coupling-out grating 213.

[0151] Optionally, the turning grating 214 may be, but is not limited to, one of a binary grating, a tilted grating, a blazed grating, a two-dimensional grating, etc. The turning grating 214, the coupling-in grating 212 and the coupling-out grating 213 may be of the same type or different types.

[0152] See also Fig.17 and Fig.18 In some embodiments, the waveguide module 200 of the embodiment of the present application further includes a protective lens 230, which is stacked and spaced apart on the side of the optical waveguide 210 away from the cover plate 100, for protecting the optical waveguide 210. It can be understood that the cover plate 100, the optical waveguide 210 and the protective lens 230 are stacked and spaced apart in sequence. By providing the protective lens 230, the surface of the optical waveguide 210 facing the wearer can also be protected, which can better prevent the optical waveguide 210 from being scratched, improve the drop resistance of the optical waveguide 210, and increase the life of the waveguide module 200.

[0153] Optionally, the thickness of the protective lens 230 is uniform, and the protective lens 230 cannot change the incident angle of the light incident on the outcoupling grating 213. It can be understood that the surface of the protective lens 230 facing the optical waveguide 210 is parallel to the surface of the protective lens 230 away from the optical waveguide 210.

[0154] Optionally, the protective lens 230 may be translucent or semi-translucent (e.g., ink, brown, gray, etc.). Optionally, the material of the protective lens 230 may be at least one of glass material and resin material. The resin material may be, but is not limited to, at least one of polymethyl methacrylate, polycarbonate, and other resins.

[0155] Optionally, the thickness of the protective lens 230 may be 0.3 mm to 1 mm; specifically, it may be, but not limited to, 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, etc. If the protective lens 230 is too thin, it will not provide sufficient protection for the optical waveguide 210; if the protective lens 230 is too thick, the thickness of the waveguide module 200 will be increased, which is not conducive to the thinness of the waveguide module 200.

[0156] In some embodiments, the waveguide module 200 further includes a first adhesive member 250 and a second adhesive member 270; the first adhesive member 250 is disposed between the optical waveguide 210 and the cover plate 100, and is disposed around the periphery of the optical waveguide 210, for bonding the cover plate 100 to the optical waveguide 210, and spacing the optical waveguide 210 and the cover plate 100, so that an air gap exists between the optical waveguide 210 and the cover plate 100; the second adhesive member 270 is disposed between the optical waveguide 210 and the protective lens 230, and is disposed around the periphery of the optical waveguide 210, for bonding the protective lens 230 to the optical waveguide 210, and spacing the optical waveguide 210 and the protective lens 230.

[0157] Optionally, the first adhesive member 250 and the second adhesive member 270 are both middle frame structures or ring structures. Optionally, the first adhesive member 250 can be, but not limited to, a plastic frame, optical adhesive (i.e., OCA adhesive), etc.; the second adhesive member 270 can be, but not limited to, a plastic frame, optical adhesive (i.e., OCA adhesive), etc. In other embodiments, the first adhesive member 250 and the second adhesive member 270 can also be polymer micro-pillars arranged at intervals.

[0158] See also Figures 19 to 21 The embodiment of the present application further provides an augmented reality device 300, which includes a projection optical machine 310, a waveguide module 200 of the above embodiment of the present application, and a processor 350. The projection optical machine 310 is used to project a light signal, and the light signal includes image information; the waveguide module 200 is used to transmit the light signal, and the cover plate 100 is farther away from the projection optical machine than the light waveguide 210; the processor 350 is electrically connected to the projection optical machine 310, and is used to control the projection optical machine 310 to project the light signal, thereby displaying image information.

[0159] The augmented reality device 300 of the embodiment of the present application may be, but is not limited to, a near-eye display system such as augmented reality glasses, an augmented reality helmet, an augmented reality mask, etc. In the drawings of the present application, the augmented reality device 300 is illustrated by taking augmented reality glasses as an example, which should not be understood as a limitation on the augmented reality device 300 of the present application, nor should it be understood as a limitation on the waveguide module 200 of the present application.

[0160] For a detailed description of the waveguide module 200 , please refer to the description of the corresponding part of the above embodiment, which will not be repeated here.

[0161] Optionally, the projection optical machine 310 includes a display 311 and a lens 313. The display 311 is electrically connected to the processor 350, and is used to emit a light signal with image information under the control of the processor 350; the lens 313 is arranged on the display surface side of the display 311, and is used to modulate the light signal, so that the light (light signal) of different viewing angles emitted from the same pixel point on the display 311 is modulated by the lens 313 and emitted in the form of parallel light, so that the image information in the light signal is at an infinite position so that it can be seen by the naked eye. The waveguide module 200 is arranged on the side of the lens 313 away from the display 311, and is used to transmit the light signal modulated by the lens 313.

[0162] In one embodiment, the coupling-in grating 212 and the coupling-out grating 213 of the optical waveguide 210 are disposed away from the projection optical engine 310. In another embodiment, the coupling-in grating 212 and the coupling-out grating 213 of the optical waveguide 210 are disposed toward the projection optical engine 310.

[0163] In some embodiments, the waveguide module 200 can also dilate the image information in the optical signal emitted by the lens 313 in one dimension or two dimensions to increase the range of the eye orbit, thereby accommodating more people.

[0164] Optionally, the processor 350 includes one or more general-purpose processors, wherein the general-purpose processor can be any type of device capable of processing electronic instructions, including a central processing unit (CPU), a microprocessor, a microcontroller, a main processor, a controller, and an ASIC, etc. The processor 350 is used to execute various types of digital storage instructions, such as software or firmware programs stored in a memory, which enables the computing device to provide a wide variety of services.

[0165] Optionally, the augmented reality device 300 of the embodiment of the present application further includes a memory 360. The memory 360 is electrically connected to the processor 350 and is used to store program codes required for the processor 350 to run, program codes required for controlling the display 311, image information emitted by the display 311, and the like.

[0166] Optionally, the memory 360 may include a volatile memory (Volatile Memory), such as a random access memory (Random Access Memory, RAM); the memory 360 may also include a non-volatile memory (NVM), such as a read-only memory (Read-Only Memory, ROM), a flash memory (Flash Memory, FM), a hard disk drive (Hard Disk Drive, HDD) or a solid-state drive (SSD). The memory 360 may also include a combination of the above-mentioned types of memory.

[0167] In some embodiments, the augmented reality device 300 further includes a carrier 320 for carrying the waveguide module 200 , and the optical waveguide 210 , the cover plate 100 , and the protective lens 230 are assembled into one body with the carrier 320 .

[0168] Optionally, the carrier 320 may be, but is not limited to, a frame of augmented reality glasses, a helmet body of an augmented reality helmet, a mask body of an augmented reality mask, etc. Optionally, the waveguide module 200 may be disposed on the carrier 320 by an adhesive or a fastening portion.

[0169] In some embodiments, when the augmented reality device 300 is an augmented reality glasses, the augmented reality device 300 of the embodiment of the present application further includes a wearing member 330. The wearing member 330 is rotatably connected to the bearing member 320, and the wearing member 330 is used to clamp the wearer (such as a human head, or a head prosthesis, etc.).

[0170] Optionally, the wearing component 330 includes a first wearing component 331 and a second wearing component 333, wherein the first wearing component 331 is rotatably connected to one end of the supporting component 320, and the second wearing component 333 is rotatably connected to the other end of the supporting component 320 away from the first wearing component 331. The first wearing component 331 cooperates with the second wearing component 333 to clamp the augmented reality device 300 to the wearer. Optionally, the first wearing component 331 and the second wearing component 333 are also used to set the projection light machine 310. Optionally, the first wearing component 331 and the second wearing component 333 can be, but are not limited to, the temples of the augmented reality device 300 (AR glasses).

[0171] Mentioning "embodiment" and "implementation method" in this application means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrases in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments. In addition, it should also be understood that the features, structures or characteristics described in the various embodiments of the present application can be arbitrarily combined to form another embodiment that does not deviate from the spirit and scope of the technical solution of the present application, provided that there is no contradiction between them.

[0172] Finally, it should be noted that the above implementation modes are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the above preferred implementation modes, a person of ordinary skill in the art should understand that the technical solution of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present application.

Claims

1. A cover plate, characterized in that: include: A body layer, wherein the body layer has a preset surface; as well as A dimming layer, wherein the dimming layer includes a plurality of dimming parts, wherein the plurality of dimming parts are randomly distributed on the preset surface, and when the incident angle of light on the preset surface is less than a preset angle, the dimming layer has a first transmittance T1, and when the incident angle of light on the preset surface is greater than a preset angle, the dimming layer has a second transmittance T2, and the plurality of dimming parts cooperate to make T1 ≥ 70% and T2 ≤ 20%, wherein the range of the preset angle is 45° to 75°.

2. The cover plate according to claim 1, characterized in that: The random distribution degree of the plurality of dimming units is k, and the range of the random distribution degree k is: k≥10%.

3. The cover plate according to claim 1, characterized in that: The maximum height of each dimming part is h, and the maximum width of the orthographic projection of the dimming part on the preset surface is d, wherein 0.1≤h / d≤20.

4. The cover plate according to claim 3, characterized in that: The range of the maximum width d of the orthographic projection of each dimming unit on the preset surface is: 1um≤d≤200um.

5. The cover plate according to claim 3, characterized in that: The maximum height h of each dimming unit is in the range of 1um≤h≤200um.

6. The cover plate according to claim 3, characterized in that: The range of the minimum gap s between any two adjacent dimming parts is: 0.1um≤s≤1000um.

7. The cover plate according to any one of claims 1 to 6, characterized in that: The dimming part includes ink and magnetic particles, the magnetic particles are dispersed in the ink, and the mass fraction w% of the magnetic particles in the dimming part is in the range of 20%≤w%≤50%.

8. The cover plate according to claim 7, characterized in that: The particle size of the magnetic particles ranges from 5 nm to 300 nm.

9. The cover plate according to any one of claims 1 to 6 and 8, characterized in that: The cover plate further includes a filling layer, which fills the gaps between the plurality of dimming parts and covers the surfaces of the dimming parts facing away from the main layer, and the filling layer is light-transmissive.

10. The cover plate according to claim 9, characterized in that: The cover plate further includes a first anti-glare layer and a second anti-glare layer. The first anti-glare layer is arranged on a surface of the filling layer away from the main body layer; the second anti-glare layer is arranged on a surface of the main body away from the dimming layer.

11. A method for preparing a cover plate, characterized in that: include: Providing a body layer, wherein the body layer has a predetermined surface; as well as A dimming layer is formed on a preset surface of the main layer, the dimming layer includes a plurality of dimming parts, the plurality of dimming parts are randomly distributed on the preset surface, when the incident angle of light on the preset surface is less than a preset angle, the dimming layer has a first transmittance T1, when the incident angle of light on the preset surface is greater than a preset angle, the dimming layer has a second transmittance T2, the plurality of dimming parts cooperate to make T1 ≥ 70% and T2 ≤ 20%, wherein the preset angle ranges from 45° to 75°.

12. The method for preparing a cover plate according to claim 11, characterized in that: The step of forming a dimming layer on a preset surface of the body layer comprises: forming an anti-fingerprint layer on the preset surface of the body layer; Providing a mask plate, and stacking the mask plate on a surface of the anti-fingerprint layer away from the main layer, wherein the mask plate has a plurality of randomly distributed first through holes; Removing a portion of the anti-fingerprint layer that overlaps with the plurality of first through holes, so that a plurality of second through holes that are randomly distributed are formed on the anti-fingerprint layer, and removing the mask plate; Coating a slurry on a surface of the anti-fingerprint layer facing away from the body layer to form a plurality of randomly distributed droplets in the plurality of second through holes; and The plurality of liquid droplets are solidified to form a dimming layer, wherein the dimming layer includes a plurality of dimming parts.

13. The method for preparing a cover plate according to claim 12, characterized in that: The slurry is a magnetic slurry. After forming a plurality of randomly distributed droplets in the plurality of second through holes and before solidifying the plurality of droplets to form a dimming layer, the method further includes: A magnetic field is applied to increase the height of the plurality of droplets.

14. A waveguide module, characterized in that: include: An optical waveguide, the optical waveguide being used to transmit an optical signal incident into the optical waveguide; as well as The cover plate according to any one of claims 1 to 10, wherein the cover plate and the optical waveguide are stacked and spaced apart to protect the optical waveguide.

15. An augmented reality device, characterized in that: include: A projection optical machine, the projection optical machine is used to project a light signal, the light signal includes image information; The waveguide module of claim 14, wherein the waveguide module is used to transmit the optical signal, and the cover plate is farther away from the projection optical machine than the optical waveguide; and A processor is electrically connected to the projection optical machine and is used to control the projection optical machine to project the light signal.

Images