Cover plate and manufacturing method thereof, diffraction waveguide device and near-to-eye display equipment

Abstract

The invention provides a cover plate and a manufacturing method thereof, a diffraction waveguide device and near-to-eye display equipment. The cover plate comprises a lens and a plurality of light absorbers distributed in the lens at intervals; the lens is used for receiving natural light, the natural light comprises first light and second light, the incident angle of the first light is larger than a critical angle, the incident angle of the second light is smaller than the critical angle, and the critical angle is 45-75 degrees; the distribution of the light absorbers enables the first light to be blocked and not to penetrate through the lens and the second light to penetrate through the lens. According to the cover plate provided by the invention, the plurality of light absorbers are distributed in the middle of the lens at intervals to form the cover plate, when the lens receives the natural light of the external environment, the first light with the incident angle larger than the critical angle can be blocked by the light absorbers and cannot be emitted out of the lens, and the second light with the incident angle smaller than the critical angle can be emitted out of the lens; therefore, the rainbow lines can be eliminated or weakened when the use experience of augmented reality is realized.

Description

Technical Field

[0001] The present application relates to the technical field of electronic equipment, and specifically to a cover plate and a manufacturing method thereof, a diffraction waveguide device, and a near-eye display device. Background Art

[0002] Augmented reality is a technology that integrates virtual information with the real world, and near-eye display devices are a key link in augmented reality technology. Near-eye display devices allow users to see the real world while seeing virtual images constructed by computers. However, based on the fact that the external ambient light is light of different wavelengths, when it is coupled into the human eye through the waveguide, light of different wavelengths will enter the human eye at different angles, so linear or halo-shaped color images, i.e. rainbow patterns, 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 of the invention

[0003] The present application aims to provide a cover plate and a method for manufacturing the same, a diffraction waveguide device, and a near-eye display device, so as to solve the technical problem in the related art that rainbow patterns interfere with the vision in near-eye display devices.

[0004] On one hand, an embodiment of the present application provides a cover plate, which includes a lens and a plurality of light absorbers spaced apart in the lens; wherein the lens is configured to receive natural light, the natural light includes a first light ray and a second light ray, the incident angle of the first light ray is greater than a critical angle, the incident angle of the second light ray is less than the critical angle, and the critical angle is 45°-75°; the distribution of the light absorbers is such that the first light ray is blocked from passing through the lens, while the second light ray can pass through the lens.

[0005] On the other hand, an embodiment of the present application provides a diffraction waveguide device, which includes a waveguide plate and a cover plate arranged on the waveguide plate; wherein the cover plate includes a lens arranged on the waveguide plate, and a plurality of light absorbers spaced apart in the lens; the lens is configured to receive natural light, the natural light includes a first light ray and a second light ray, the incident angle of the first light ray is greater than a critical angle, the incident angle of the second light ray is less than the critical angle, and the critical angle is 45°-75°; the distribution of the light absorbers is such that the first light ray is blocked from passing through the lens, while the second light ray can pass through the lens.

[0006] On the other hand, an embodiment of the present application further provides a near-eye display device, the near-eye display device includes a frame and a diffraction waveguide device, the diffraction waveguide device is assembled on the frame; the diffraction waveguide device includes a waveguide plate and a cover plate arranged on the waveguide plate; wherein the cover plate includes a lens arranged on the waveguide plate, and a plurality of light absorbers distributed at intervals in the lens; the lens is configured to receive natural light, the natural light includes a first light ray and a second light ray, the incident angle of the first light ray is greater than a critical angle, and the incident angle of the second light ray is less than the critical angle, and the critical angle is 45°-75°; the distribution of the light absorbers is such that the first light ray is blocked from passing through the lens, and the second light ray can pass through the lens.

[0007] On the other hand, an embodiment of the present application further provides a method for manufacturing a cover plate, the manufacturing method comprising: providing a lens, and forming a plurality of grooves arranged at intervals on the lens; filling the grooves with light-absorbing material to form a light-absorbing body; wherein the lens is configured to receive natural light, the natural light comprises a first light ray and a second light ray, the incident angle of the first light ray is greater than a critical angle, the incident angle of the second light ray is less than the critical angle, and the critical angle is 45°-75°; the distribution of the light-absorbing body is such that the first light ray is blocked from passing through the lens, while the second light ray can pass through the lens.

[0008] The cover plate and its manufacturing method, diffraction waveguide device, and near-eye display device provided in the embodiments of the present application form a cover plate by distributing a number of light absorbers at intervals in the lens. When the lens receives natural light from the external environment, the first light with an incident angle greater than the critical angle can be blocked by the light absorber and cannot be emitted from the lens, while the second light with an incident angle less than the critical angle can be emitted from the lens, thereby eliminating or reducing rainbow lines when realizing the use experience of augmented reality, preventing the rainbow lines from blocking the line of sight and eye fatigue caused by long-term use, and significantly improving the user experience. In addition, the present application adopts the cover plate made by filling the groove on the lens with light absorbers, so that the overall thickness of the diffraction waveguide device is relatively thin, thereby making the diffraction waveguide device thinner. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of 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.

[0010] Figure 1 is a schematic structural diagram of a near-eye display device provided in an embodiment of the present application;

[0011] Figure 2 is another structural schematic diagram of a near-eye display device provided in an embodiment of the present application;

[0012] Figure 3 is another structural schematic diagram of a near-eye display device provided in an embodiment of the present application;

[0013] Figure 4 is a schematic diagram of the cross-sectional structure of the diffraction waveguide device provided in an embodiment of the present application when assembled with a frame;

[0014] Figure 5 is a schematic diagram of the cross-sectional structure of a diffraction waveguide device provided in an embodiment of the present application;

[0015] Figure 6 is another schematic cross-sectional structure diagram of the diffraction waveguide device provided in an embodiment of the present application;

[0016] Figure 7 is a schematic structural diagram of a diffraction waveguide device in some embodiments of the present application;

[0017] Figure 8 yes Figure 7 A schematic diagram of the top view of the cover plate in the embodiment;

[0018] Fig. 9 is a schematic flow chart of a method for manufacturing a cover plate in some embodiments of the present application;

[0019] Fig.10 It is a schematic flow chart of a method for manufacturing a diffraction waveguide device in some embodiments of the present application. DETAILED DESCRIPTION

[0020] The present application is further described in detail below in conjunction with the accompanying drawings and examples. It is particularly noted that the following examples are only used to illustrate the present application, but are not intended to limit the scope of the present application. Similarly, the following examples are only some embodiments of the present application rather than all embodiments, and all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0021] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations 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 herein may be combined with other embodiments.

[0022] The present application describes a near-eye display device and a head-mounted device. The near-eye display device and the head-mounted device can be an augmented reality or virtual reality device, such as augmented reality or virtual reality glasses. Of course, in addition to augmented reality or virtual reality, the near-eye display device and the head-mounted device may also have other functions such as lighting and video recording, which are not described one by one here. The following is a detailed description of the near-eye display device and the head-mounted device as augmented reality or virtual reality glasses. In the example of augmented reality or virtual reality glasses, the near-eye display device and the head-mounted device may be configured to transfer data to an external processing device and receive data from an external processing device via a signal connection, and the signal connection may be a wired connection, a wireless connection, or a combination thereof. However, in other cases, the near-eye display device and the head-mounted device can be used as independent devices, that is, data processing is performed on the near-eye display device and the head-mounted device itself. The signal connection can be configured to carry any kind of data, such as image data (e.g., still images and / or full motion video, including 2D and 3D images), audio, multimedia, voice and / or any other type of data. The external processing device may be, for example, a game console, a personal computer, a tablet computer, a smart phone, or other type of processing device. The signal connection may be, for example, a universal serial bus (USB) connection, a Wi-Fi connection, a Bluetooth or Bluetooth Low Energy (BLE) connection, an Ethernet connection, a cable connection, a DSL connection, a cellular connection (e.g., 3G, LTE / 4G, or 5G), etc., or a combination thereof. Additionally, the external processing device may communicate with one or more other external processing devices via a network, which may be or include, for example, a local area network (LAN), a wide area network (WAN), an intranet, a metropolitan area network (MAN), the global Internet, or a combination thereof.

[0023] Among them, diffraction waveguide devices, optical machine modules, sensors, processors, etc. can be installed in near-eye display devices and head-mounted devices. In the example of augmented reality or virtual reality glasses, the diffraction waveguide device is designed to, for example, realize the function of virtual reality glasses by projecting light into the user's eyes, for example, by projecting light into the user's eyes and overlaying images on the user's view of their real-world environment to realize the function of augmented reality glasses. The near-eye display device and the head-mounted device may also include a natural light sensor, and may also include an electronic circuit system to control at least some of the above components and perform associated data processing functions. The electronic circuit system may include, for example, one or more processors and one or more memories.

[0024] See also Figure 1 to Figure 2 , Figure 1 is a schematic structural diagram of a near-eye display device 10 provided in an embodiment of the present application, Figure 2 It is another structural schematic diagram of the near-eye display device 10 provided in an embodiment of the present application.

[0025] The near-eye display device 10 provided in the embodiment of the present application can be used to realize the function of a virtual reality or augmented reality environment. The near-eye display device 10 may include a device body 100 and a diffractive waveguide device 300 mounted on the device body 100. The diffractive waveguide device 300 can present a virtual reality or augmented reality environment under the control of the device body 100.

[0026] Specifically, the diffractive waveguide device 300 can display images for the user under the control of the device body 100. The user can observe real-world objects through the diffractive waveguide device 300, and at the same time, overlay computer-generated content on the real-world objects by presenting computer-generated images on the diffractive waveguide device 300.

[0027] The device body 100 may be provided with an optical machine module 101, and the optical machine module 101 is arranged opposite to the diffraction waveguide device 300. The diffraction waveguide device 300 can present a virtual reality or augmented reality environment under the control of the optical machine module 101. Specifically, the optical machine module 101 can emit light to illuminate the diffraction waveguide device 300, and the diffraction waveguide device 300 can transmit the light emitted by the optical machine module 101 to the user's eyes for imaging, thereby realizing the virtual reality or augmented reality environment function of the near-eye display device 10. Of course, in addition to the optical machine module 101, the device body 100 can also be installed with functional modules such as batteries, sensors and speakers to realize other functions of the near-eye display device 10. Among them, the specific structure and implementation principle of the optical machine module 101 can refer to the existing technology and will not be repeated here.

[0028] like Figure 1 As shown, the device body 100 may include a frame 110 and an external part 120. The frame 110 may be provided on one side of the external part 120, and the frame 110 may be used to install the diffraction waveguide device 300. The external part 120 may be detachably connected to the frame 110. For example, the external part 120 and the frame 110 may be magnetically connected via a magnet. In this way, when the external part 120 is hung at a specified position, the diffraction waveguide device 300 may be arranged opposite to the user's eyes. For example, when the external part 120 is hung on the user's ear, the user can conveniently use the near-eye display device 10.

[0029] like Figure 2As shown, the device body 100 may include a frame 110 and a wearing piece 130. The wearing piece 130 may be disposed on one side of the frame 110, and the frame 110 may be used to install the diffraction waveguide device 300. The wearing piece 130 may be detachably connected to the frame 110. For example, the wearing piece 130 and the frame 110 may be magnetically connected via a magnet. In this way, when the wearing piece 130 is worn on the user's head, the diffraction waveguide device 300 may be disposed opposite to the user's eyes, and the wearing piece 130 may be located on the user's head, so that the user can use the near-eye display device 10.

[0030] Among them, the optical machine module 101 can be located at the end where the external component 120 or the wearable component 130 is connected to the frame 110, and is arranged opposite to the diffraction waveguide device 300 on the frame 110.

[0031] Understandably, Figure 1 , a usage scenario in which the near-eye display device 10 is a plug-in device is illustrated, and a diffraction waveguide device 300 corresponding to the left eye or the right eye is mounted on the frame 110 . Figure 2 , a use scenario in which the near-eye display device 10 is a head-mounted device is illustrated, and a diffraction waveguide device 300 corresponding to the left eye and / or the right eye is mounted on the frame 110. When the near-eye display device 10 is a smart pair of glasses, the wearing piece 130 may be a temple. When the near-eye display device 10 is a smart helmet, the wearing piece 130 may be a helmet.

[0032] Of course, in other usage scenarios, the near-eye display device 10 can also be designed into other desired shape structures. For example, the near-eye display device 10 can also include portable consumer electronic devices (e.g., portable electronic devices such as smart helmets, augmented reality or virtual reality glasses, or other wearable devices), overhead displays in cockpits, vehicles, etc., and display-based devices (projectors, televisions, etc.). Devices such as these near-eye display devices 10 may include a diffraction waveguide device 300 and other optical components, and the device configuration in which virtual reality and / or augmented reality content is provided to a user with a head-mounted display is described as an example in this article. However, this is merely illustrative. Any suitable device can be used to provide virtual reality and / or augmented reality content to a user.

[0033] The near-eye display device 10 can be used to provide computer-generated content overlaid on real-world content to the user. The real-world content can be directly viewed by the user through the diffractive waveguide device 300, and the computer-generated content can be transmitted to the diffractive waveguide device 300 through the optical-mechanical module 101 for the user to view.

[0034] All directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0035] See also Figure 3 , Figure 3 1 is another structural diagram of the near-eye display device 10 provided in an embodiment of the present application. The near-eye display device 10 may be augmented reality or virtual reality glasses, or other wearable devices.

[0036] The near-eye display device 10 may include a device body 200 and a diffractive waveguide device 300, and the device body 200 may include a frame 210 and a clamp 220. The frame 210 may be used to install the diffractive waveguide device 300. The optical machine module 101 may be located at the end where the clamp 220 is connected to the frame 210, and is arranged opposite to the diffractive waveguide device 300 on the frame 210. The clamp 220 is detachably connected to the frame 210.

[0037] For example, the clamp 220 and the frame 210 can be connected by magnets. In this way, when the clamp 220 is worn on the user's head, the diffraction waveguide device 300 can be arranged opposite to the user's eyes, and the clamp 220 can be located on the side of the user's ear, so that the user can use the near-eye display device 10.

[0038] The frame 210 may be formed by connecting two frames 110 in the aforementioned embodiment, so that two diffraction waveguide devices 300 can be installed on the frame 210 at the same time. Clamps 220 may be provided on opposite sides of the frame 210, and the frame 210 and / or the clamps 220 may also be provided with installation spaces for installing functional modules required for the near-eye display device 10. The optical machine module 101 may be arranged in the installation space of the frame 210 or the clamps 220. The diffraction waveguide device 300 may be arranged on the frame 210, and the diffraction waveguide device 300 may be arranged opposite to the optical machine module 101 on the clamps 220, and may present a virtual reality or augmented reality environment under the control of the optical machine module 101.

[0039] It can be understood that when the near-eye display device 10 is a smart glasses, the frame 210 can be a frame, and the clamping member 220 can be a temple. For the specific structure and connection method of the frame and the temple, reference can be made to the prior art. The connection method of the diffraction waveguide device 300 and the frame 210 is the same or similar to the connection method of the diffraction waveguide device 300 and the frame 110 in the aforementioned embodiment, and will not be repeated here. It should be noted that the frame 210 and the frame 110 are terms used only to distinguish between an integrated near-eye display device 10 and an external near-eye display device 10. The two can be the same or similar in structure, and in some embodiments, the frame can also be referred to as a frame, and the frame can also be referred to as a frame.

[0040] It should be noted that the terms "installation", "connection" and the like in the embodiments of the present application should be understood in a broad sense unless otherwise clearly specified and limited. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or the internal connection of two components. For those skilled in the art, the specific meanings of the above terms in this article can be understood according to specific circumstances.

[0041] See also Figure 4 , Figure 4 1 is a schematic diagram of the cross-sectional structure of the diffractive waveguide device 300 and the frame 110 provided in the embodiment of the present application when they are assembled. The frame 110 can be used to assemble the diffractive waveguide device 300.

[0042] The frame 110 may be surrounded to form an installation space 102 for installing the diffraction waveguide device 300, and the shape of the installation space 102 may be adapted to the diffraction waveguide device 300. The diffraction waveguide device 300 may have a first surface 301 and a second surface 302 arranged opposite to each other, and a third surface 303 connecting the first surface 301 and the second surface 302. The first surface 301 and the second surface 302 may be two surfaces arranged opposite to each other in the thickness direction of the diffraction waveguide device 300. Specifically, when the user wears the diffraction waveguide device 300 in front of the eyes, the first surface 301 may be a side of the diffraction waveguide device 300 facing the user's eyes, and the second surface 302 may be a side of the diffraction waveguide device 300 facing away from the user's eyes. Optionally, the first surface 301 and the second surface 302 may be surfaces perpendicular to the thickness direction of the diffraction waveguide device 300, respectively. Furthermore, the first surface 301 and / or the third surface 303 of the diffractive waveguide device 300 may be connected and fixed to the frame 110 by bonding, clamping, welding or screwing.

[0043] In one embodiment, the frame 110 may be provided in an annular structure, and its annular hollow area is configured to form the above-mentioned installation space 102. The first surface 301 and / or the third surface 303 of the diffractive waveguide device 300 may be connected and fixed to the annular inner wall of the frame 110 by bonding, clamping, welding or screwing.

[0044] like Figure 4 As shown, the frame 110 may include a frame body portion 111 and a bearing portion 112 connected in a bent manner. The frame body portion 111 may be configured to enclose the installation space 102 for installing the diffraction waveguide device 300, and the shape of the installation space 102 may be adapted to the diffraction waveguide device 300. The bearing portion 112 may be disposed in the installation space 102, and the bearing portion 112 may be disposed in a ring shape, which may be used to support the diffraction waveguide device 300, so as to fix the diffraction waveguide device 300 in the installation space 102.

[0045] Optionally, the frame portion 111 may be provided in an annular structure, and its annular hollow area is configured to form the above-mentioned installation space 102. The bearing portion 112 may be connected to the annular inner wall of the frame portion 111.

[0046] The first surface 301 of the diffractive waveguide device 300 can be fixedly connected to the carrier portion 112 through the colloid 103. Of course, in other embodiments, the colloid 103 can also be provided between the third surface 303 of the diffractive waveguide device 300 and the frame portion 111 to connect the diffractive waveguide device 300 and the frame portion 111. The colloid 103 can be an optical glue, a UV curable glue or other colloids.

[0047] Optionally, the connection method between the frame 110 and the diffractive waveguide device 300 is not limited to that in the aforementioned embodiment. For example, the frame 110 may also be designed as a split type, so that the frame 110 is split into two parts, and the diffractive waveguide device 300 is clamped in the middle and assembled by screw locking or adhesive fixing. Figure 4 The content is merely a schematic illustration of the connection between the frame 110 and the diffraction waveguide device 300 and is not intended to be limiting.

[0048] Furthermore, the bearing portion 112 of the frame 110 may be arranged to form an optical channel 104 communicating with the installation space 102. When the diffraction waveguide device 300 is disposed in the installation space 102, the first surface 301 of the diffraction waveguide device 300 may be disposed opposite to the optical channel 104. As described above, the optical module 101 may emit light to irradiate the diffraction waveguide device 300, and the diffraction waveguide device 300 may transmit the light emitted by the optical module 101 to the user's eyes through the optical channel 104 for imaging; or, external natural light may irradiate the diffraction waveguide device 300, and the diffraction waveguide device 300 may transmit the external natural light to the user's eyes through the optical channel 104.

[0049] See also Figure 5 , Figure 5 It is a schematic diagram of the cross-sectional structure of the diffraction waveguide device 300 provided in an embodiment of the present application.

[0050] The diffractive waveguide device 300 may include a lens 310 and a waveguide sheet 320 which are stacked, and the lens 310 is configured to receive external natural light. When the user wears the diffractive waveguide device 300 in front of the eye, the waveguide sheet 320 may be the side of the diffractive waveguide device 300 facing the user's eye, and the lens 310 may be the side of the diffractive waveguide device 300 facing away from the user's eye, so as to protect the waveguide sheet 320.

[0051] Optionally, one surface of the diffraction waveguide device 300 (the surface of the waveguide plate 320 facing away from the lens 310) can be a first surface 301, and the other surface of the diffraction waveguide device 300 (the surface of the lens 310 facing away from the waveguide plate 320) can be a second surface 302.

[0052] Furthermore, the waveguide 320 can not only present the natural light passing through the lens 310 to the user's eyes for viewing, but also transmit the light emitted from the optical module 101 to the user's eyes. Specifically, natural light can enter the human eye through the lens 310 and the waveguide 320 in sequence, and the light from the optical module 101 can be guided to the waveguide 320, and the waveguide 320 can guide the light to the user's eyes. In this way, the user can see the real world content and the superimposed image at the same time, thereby realizing the superposition of the virtual image and the real environment. The waveguide 320 can be connected and fixed to the frame 110 by bonding, clamping, welding or screwing.

[0053] In one embodiment, the diffraction waveguide device 300 may further include a grating structure 330 disposed on the surface of the waveguide plate 320, and the grating structure 330 may include an out-coupling grating 331 and an in-coupling grating 332. The in-coupling grating 332 is configured to couple light into the waveguide plate 320, and the out-coupling grating 331 is configured to receive light after total reflection from the waveguide plate 320, and couple the light out of the waveguide plate 320 after two-dimensional pupil expansion. Further, the grating structure 330 may be disposed on a surface of the waveguide plate 320 that is away from the lens 310.

[0054] It can be understood that in general scenarios, the waveguide plate 320, the out-coupling grating 331 and the in-coupling grating 332 can be collectively referred to as a waveguide component, that is, the waveguide plate 320, the out-coupling grating 331 and the in-coupling grating 332 can be an integrated structure.

[0055] Specifically, when the diffraction waveguide device 300 is in use, the light of the display image generated by the image source 350 enters the waveguide plate 320 through the coupling-in grating 225, and is emitted to the coupling-out grating 331 after total reflection by the waveguide plate 320, and then is emitted to the human eye 360 ​​after coupling out of the coupling-out grating 331. Among them, the image source 350 is a device that generates the original image. The image source 350 can be the optical machine module 101 in the aforementioned embodiment, but is not limited thereto, for example, it can also be a Micro-LED display screen, etc. The light guide plate 320 can also be called an optical waveguide substrate, a dielectric optical waveguide substrate, or a waveguide substrate plate, which is a medium for guiding the propagation of light therein. Generally, the waveguide plate 320 is a guiding structure for transmitting light (optical frequency electromagnetic waves) composed of an optically transparent medium (such as quartz glass). When the light is transmitted in the waveguide plate 320, it will be totally reflected in the waveguide plate 320, so that the light is confined to propagate in the waveguide plate 320.

[0056] It can be understood that total reflection means that there is no loss or leakage in the transmission process of light. "Total reflection" is required so that the light is reflected back and forth in the waveguide in a wave shape and does not transmit out. Total reflection needs to meet two conditions: (1) The transmission medium, that is, the waveguide substrate, needs to have a higher refractive index than the surrounding medium; (2) The incident angle of light entering the waveguide substrate needs to be greater than the critical angle.

[0057] See also Figure 6 , Figure 6 is another cross-sectional structural diagram of the diffraction waveguide device 300 provided in an embodiment of the present application. Figure 6 Example and Figure 5 The only difference in the embodiment is that the grating structure 330 can be disposed on a surface of the waveguide plate 320 close to the lens 310. Therefore, other identical or similar features will not be described in detail.

[0058] like Figure 5 and Figure 6As shown, when the external ambient light is incident on the diffraction waveguide device 300 and reaches the outcoupling grating, if the incident angle of the external ambient light incident on the diffraction waveguide device 300 is higher than a certain critical angle θ, the diffraction angle after the outcoupling grating is lower than the total reflection angle, and the ambient light will be coupled out and enter the human eye. Since the ambient light is a mixture of light of different colors, and the wavelengths of light of different colors are different, the diffraction angles are different. Therefore, 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 color images, i.e., rainbow patterns, which will seriously interfere with the normal vision of the human eye, and long-term wearing will easily cause visual fatigue. Among them, the above critical angle θ is generally affected by factors such as the refractive index of the waveguide itself, the grating period, and the grating refractive index, that is, the above critical angle θ of different diffraction waveguide devices 300 is different. Optionally, the critical angle θ can be 45°-75°. For example, the critical angle θ can be 45°, 50°, 55°, 60°, 65° or 70°, etc.

[0059] Furthermore, the external ambient light may include a first light ray X1 having an incident angle greater than a critical angle θ and a second light ray X2 having an incident angle less than the critical angle θ. When the first light ray X1 is coupled into the human eye through the outcoupling grating, light of different colors will enter the human eye at different angles, so that a linear or halo-shaped color image, i.e., a rainbow pattern, will be perceived, and the second light ray X2 may pass through the diffraction waveguide device 300 and reach the human eye.

[0060] Based on this, the present application further improves the above-mentioned embodiment to improve the technical problem of the above-mentioned rainbow pattern.

[0061] See also Figure 7 , Figure 7 Schematic diagram of the structure of the diffraction waveguide device 300 in some embodiments of the present application.

[0062] The diffraction waveguide device 300 may include a waveguide plate 320 and a cover plate 323 disposed on the waveguide plate 320. The cover plate 323 may be configured to receive and filter natural light so that part of the natural light received by the cover plate 323 can reach and pass through the waveguide plate 320, that is, the cover plate 323 may change its own light transmittance so that part of the natural light can pass through the cover plate 323.

[0063] Specifically, the cover plate 323 can block the ambient natural light with an incident angle higher than the critical angle, i.e., the first light X1, from reaching the waveguide plate 320, i.e., the large-angle natural light from the external environment, i.e., the first light X1, is absorbed and filtered by the cover plate 323, thereby eliminating the above-mentioned rainbow pattern. The angle of the ambient natural light refers to the angle between the ambient natural light and the normal line of the waveguide plate 320 plane.

[0064] Furthermore, the cover plate 323 can be attached to the waveguide sheet 320 by frame bonding, so that there is an escape space between the cover plate 323 and the waveguide sheet 320 to escape the grating structure 330. Of course, in other embodiments, the cover plate 323 can be fixedly assembled with the waveguide sheet 320 by bonding, clamping or other methods.

[0065] In one embodiment, the cover plate 323 may include a lens 311 disposed on the waveguide sheet 320 and a plurality of light absorbers 312 spaced apart in the lens 311. The lens 311 may be made of transparent resin, glass or other transparent materials. The lens 311 is disposed on the waveguide sheet 320 to be configured to receive natural light from the external environment. The light absorber 312 may be made of black ink or other light absorbing materials. For example, the light absorber 312 may be a black rod. The light absorbers 312 are spaced apart in the lens 311. The distribution of the light absorbers 312 blocks part of the natural light received by the lens 311 and cannot pass through the lens 311, while another part of the natural light received by the lens 311 can pass through the lens 311, thereby eliminating the above-mentioned rainbow pattern, thereby improving the user experience.

[0066] Specifically, the natural light may include a first light ray X1 and a second light ray X2, and the incident angle of the first light ray X1 is greater than the critical angle θ, and the incident angle of the second light ray X2 is less than the critical angle θ, that is, the first light ray X1 is natural light with a relatively large incident angle, and the second light ray X2 is natural light with a relatively small incident angle. The distribution of the light absorber 312 is such that the first light ray X1 is blocked from passing through the lens 311, and the second light ray X2 can pass through the lens 311. Optionally, the critical angle θ may be 45°-75°. For example, the critical angle θ may be 45°, 50°, 55°, 60°, 65° or 70°, etc.

[0067] Optionally, the lens 311 has a light incident surface 3111 and a light emitting surface 3112 that are arranged opposite to each other. The light incident surface 3111 is a side surface of the lens 311 that is away from the waveguide plate 320, so as to be configured to receive natural light from the external environment. The light emitting surface 3112 is a side surface of the lens 311 that is close to the waveguide plate 320, so that part of the natural light passing through the lens 311 can reach the waveguide plate 320 through the light emitting surface 3112. Further, there is a gap j1 between at least part of two adjacent light absorbers 312, and the natural light received by the light incident surface 3111 can partially pass through the gap j1 and be emitted from the light emitting surface 3112. That is, part of the natural light received by the light incident surface 3111 can be absorbed by the light absorber 312, and the other part can reach the light emitting surface 3112 through the gap j1 and be emitted. The first light X1 can reach the light absorber 312 through the light incident surface 3411 but is blocked by the light absorber 312 and cannot be emitted from the light emitting surface 3112 . The second light X2 can be emitted through the gap j1 and reach and pass through the lens 311 .

[0068] like Figure 7 As shown, the light incident surface 3111 and the light emitting surface 3112 define the thickness h1 of the lens 311. The light absorber 312 has a first end surface 3121 and a second end surface 3122 that are arranged opposite to each other in the thickness direction of the lens 311. The first end surface 3121 and the second end surface 3122 define the height h2 of the light absorber 312, that is, the light absorber 312 is arranged vertically along the thickness direction of the lens 311. Wherein, h1≥h2. In other words, in the direction of the normal extension of the plane of the waveguide plate 320, the lens 311 has a thickness h1, and the light absorber 312 has a height h2. Wherein, the thickness h1 of the lens 311 can be 10-200 microns, for example, 50 microns, 100 microns or 150 microns, etc. The height h2 of the light absorber 312 can be 10-200 microns, for example, 30 microns, 80 microns or 130 microns, etc. Furthermore, the thickness h1 of the lens 311 is greater than or equal to the height h2 of the light absorber 312, and the difference between the thickness h1 of the lens 311 and the height h2 of the light absorber 312 is less than or equal to 20 microns, that is, thickness h1-height h2≤20 microns.

[0069] As mentioned above, a plurality of substrates 312 are spaced apart and distributed in the lens 311. Among them, the first end surface 3121 and the second end surface 3122 can be located between the light incident surface 3111 and the light emitting surface 3112. Optionally, the first end surface 3121 is located on the side of the second end surface 3122 close to the light incident surface 3111, and the second end surface 3122 is located on the side of the first end surface 3121 close to the light emitting surface 3112. Optionally, the first end surface 3121 is not protruded from the light incident surface 3111, and the second end surface 3122 is not protruded from the light emitting surface 3112. Of course, in some embodiments, the first end surface 3121 can be coplanar with the light incident surface 3111, and / or the second end surface 3122 can be coplanar with the light emitting surface 3112.

[0070] Optionally, the light absorber 312 may be a rod, a column or other structures, and the light absorber 312 has a diameter w1. The diameter w1 of the light absorber 312 may be less than or equal to 200 microns. Optionally, the diameter w1 of the light absorber 312 is 10-200 microns, for example, 20 microns, 40 microns or 120 microns.

[0071] The diameter direction of the light absorber 312 may intersect or be perpendicular to the length direction of the light absorber 312. In other words, the diameter direction of the light absorber 312 may intersect or be perpendicular to the normal direction perpendicular to the plane of the waveguide plate 320, that is, the normal direction perpendicular to the plane of the waveguide plate 320 may be the length direction of the light absorber 312. Further, the ratio of the height h2 of the light absorber 312 to the diameter w1 of the light absorber 312 may be in the range of 0.1 to 20, for example, the ratio of h2 / w1 may be 0.5, 1, 2, 3, 4, 5, 10, or 15, etc.

[0072] Combined with reference Figure 8 , Figure 8 yes Figure 7 A schematic diagram of the top view of the cover plate 323 in the embodiment. There may be a plurality of light absorbers 312, which are arranged in the lens 311 in an irregular distribution manner.

[0073] There is a gap j1 between at least two adjacent light absorbers 312, so that part of the natural light can pass through the gap j1 and penetrate the lens 311. Further, the gap j1 can be 10-200 microns, for example, 50 microns, 100 microns or 150 microns.

[0074] It can be understood that the light absorber 312 can be used to absorb natural light to change the light transmittance of the lens 311, and further adjust the light transmittance of natural light passing through the lens 311. The light absorbers 312 are randomly distributed in the lens 311, so that part of the natural light can pass through the lens 311, and another part of the natural light is absorbed by the light absorber 312 and cannot pass through the lens 311. At the same time, the light absorbers 312 are randomly distributed in the lens 311, which can prevent strong diffraction of light between the light absorbers 312, and further prevent the human eye from having a ghosting phenomenon when observing the external environment. Figure 7 and Figure 8 As shown, the second light X2 (i.e., natural light with a smaller incident angle) can enter the human eye through the gap j1; the first light X1 (i.e., natural light with a larger incident angle) is absorbed by the light absorber 312 and cannot enter the diffraction grating, that is, the lens 311 can filter natural light with a larger incident angle. As can be seen from the above, this can eliminate rainbow patterns and improve the user experience.

[0075] In one embodiment, the heights h2 of the plurality of light absorbers 312 may be different, that is, the heights h2 may be randomly distributed, and / or the diameters w1 of the plurality of light absorbers 312 may be different, that is, the diameters w1 may be randomly distributed. As mentioned above, the light absorbers 312 are randomly distributed in the lens 311, that is, the gaps j1 may be randomly distributed.

[0076] The random degree k of the light absorber 312 in the lens 311 is defined as a comprehensive function of the random degree of the diameter w1 and the random degree of the gap j1. The random degree k is preferably greater than or equal to 10%, so as to achieve the above technical effect. It is worth mentioning that if the light absorber 312 is arranged regularly, that is, the random degree k = 0, it will have strong diffraction, and this diffraction will cause the diffraction waveguide device to be applied to the near-eye display device. When the human eye observes the external environment, there will be ghosting. For example, when wearing a near-eye display device to observe a lamp tube, there will be multiple ghost images of lamp tubes, affecting the user experience.

[0077] In one embodiment, the lens 311 may have a plurality of grooves 3113 disposed at intervals, and the plurality of grooves 3113 are configured to accommodate the light absorbers 312. The plurality of grooves 3113 are disposed in one-to-one correspondence with the plurality of light absorbers 312, that is, each groove 3113 is configured to accommodate the light absorber 312 corresponding thereto.

[0078] Furthermore, the notch of the groove 3113 may be connected to the light incident surface 3111 or the light emitting surface 3112 of the lens 311. Specifically, the groove 3113 may be formed by being recessed from the light incident surface 3111 of the lens 311 toward the direction close to the light emitting surface 3112; or, the groove 3113 may be formed by being recessed from the light emitting surface 3112 of the lens 311 toward the direction close to the light incident surface 3111. The light absorber 312 does not protrude from the notch of the groove 3113.

[0079] Optionally, the material of the light absorber 312 may be light absorbing ink, such as black ink, etc., and may be filled in the groove 3113 to form the light absorber 312. Based on this, the shape of the light absorber 312 is adapted to the shape of the groove 3113.

[0080] As can be understood from the above embodiments, the depth of the groove 3113 is substantially consistent with the length of the light absorber 312, that is, the thickness of the lens 311 can be greater than the depth of the groove 3113. Preferably, the difference between the thickness of the lens 311 and the depth of the groove 3113 is less than or equal to 20 microns. The width of the groove 3113 is substantially consistent with the width of the light absorber 312, that is, the ratio of the depth of the groove 3113 to the width of the groove 3113 can be in the range of 0.1 to 20, for example, 0.5, 1, 2, 3, 4, 5, 10, or 15.

[0081] The depth direction of the groove 3113 intersects or is perpendicular to the width direction of the groove 3113. In other words, the width direction of the groove 3113 may intersect or be perpendicular to the normal direction perpendicular to the plane of the waveguide plate 320, that is, the normal direction perpendicular to the plane of the waveguide plate 320 may be the depth direction of the groove 3113.

[0082] Similarly, the grooves 3113 can be randomly distributed in the lens 311 to accommodate the above-mentioned light absorbers 312, so that the light absorbers 312 can be randomly distributed in the lens 311, thereby avoiding strong diffraction of light between the light absorbers 312, thereby avoiding the occurrence of ghosting when the human eye observes the external environment. Optionally, the depths of several grooves 3113 can be different, that is, the depths of the grooves 3113 can be randomly distributed, and / or the widths of several grooves 3113 can be different, that is, the widths of the grooves 3113 can be randomly distributed. In combination with the foregoing, the gaps between at least some adjacent two grooves 3113 can be randomly distributed.

[0083] The randomness k of the grooves 3113 in the lens 311 is defined as a comprehensive function of the randomness of the width of the grooves 3113 and the randomness of the gap between two adjacent grooves 3113. The randomness k is preferably greater than or equal to 10%, so that the above technical effects can be achieved. It is worth mentioning that if the grooves 3113 are arranged regularly, so that the light absorbers 312 are also arranged regularly, that is, the randomness k = 0, there will be strong diffraction, and this diffraction will cause the diffraction waveguide device to be applied to the near-eye display device. When the human eye observes the external environment, there will be ghosting. For example, when wearing a near-eye display device to observe the lamp tube, there will be multiple lamp ghosts, affecting the user experience.

[0084] It should be noted that the terms "first", "second", and "third" in this application are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", and "third" may explicitly or implicitly include at least one of the features.

[0085] See also Fig. 9 , Fig. 9 is a flow chart of a method for making a cover plate in some embodiments of the present application. The method can be used to make Figure 7 The cover plate in the embodiment. The manufacturing method may include the following steps:

[0086] Step S1301: provide a lens, and form a plurality of grooves arranged at intervals on the lens.

[0087] The lens may be made of transparent resin, glass or other transparent materials, and the groove may be formed on the lens by a graphic processing process or a mechanical processing process. For example, the groove may be formed on the lens by dry etching or wet etching.

[0088] Step S1302, fill the above groove with light absorbing material, and solidify it to obtain a cover plate with light absorbing body. The light absorbing material can be black light absorbing ink or other color light absorbing ink or other light absorbing materials. The lens is configured to receive natural light, and the natural light includes a first light and a second light, and the incident angle of the first light is greater than the incident angle of the second light; the distribution of the light absorbing body makes the first light blocked from passing through the lens, and the second light can pass through the lens. Please refer to the above embodiment for details.

[0089] The light absorbing body is obtained by injecting liquid light absorbing ink into the above-mentioned groove and filling the groove, and then curing the ink. For example, the light absorbing ink can be black UV curing ink, and after the UV curing ink is injected into the groove, it can be cured by UV light. For another example, the light absorbing ink can be black water-based ink or alcohol-soluble ink, and after the UV curing ink is injected into the groove, it can be cured by baking or natural air drying.

[0090] It is understandable that the above embodiment only illustrates the method for manufacturing the cover plate, but is not limited thereto. When the cover plate is applied to the above diffraction waveguide device, the above manufacturing method can be adaptively adjusted.

[0091] See also Fig.10 , Fig.10 1 is a flow chart of a method for manufacturing a diffractive waveguide device in some embodiments of the present application. In this embodiment, the light absorber may be black ink or other ink that can absorb light.

[0092] Furthermore, the method for manufacturing the diffractive waveguide device may include the following steps:

[0093] Step S1401: provide a waveguide plate and a cover plate.

[0094] Step S1402: place a cover plate on one side of the waveguide plate to obtain a diffraction waveguide device.

[0095] It can be understood that the technical features not fully described in this embodiment can be referred to the aforementioned embodiments, so they will not be repeated here.

[0096] The cover plate and its manufacturing method, diffraction waveguide device, and near-eye display device provided in the embodiments of the present application form a cover plate by distributing a number of light absorbers at intervals in the lens. When the lens receives natural light from the external environment, the first light with a larger incident angle can be blocked by the light absorber and cannot be emitted from the lens, while the second light with a smaller incident angle can be emitted from the lens, thereby eliminating or reducing rainbow lines when realizing the use experience of augmented reality, preventing the rainbow lines from blocking the line of sight and eye fatigue caused by long-term use, and significantly improving the user experience. In addition, the present application adopts the cover plate made by filling the groove on the lens with light absorbers, so that the overall thickness of the diffraction waveguide device is relatively thin, thereby making the diffraction waveguide device thinner.

[0097] It should be noted that the terms "including" and "having" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusions. 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 may optionally include steps or units not listed, or may optionally include other steps or components inherent to these processes, methods, products or devices.

[0098] The above descriptions are only some embodiments of the present application, and do not limit the protection scope of the present application. Any equivalent device or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A cover plate for use in a diffractive waveguide device, characterized in that: The cover plate comprises: A lens, and a plurality of light absorbers spaced apart in the lens; The lens is configured to receive natural light, the natural light includes a first light ray and a second light ray, the incident angle of the first light ray is greater than a critical angle, the incident angle of the second light ray is less than the critical angle, and the critical angle is 45°-75°; The distribution of the light absorber makes the first light be blocked from passing through the lens, while the second light can pass through the lens.

2. The cover plate according to claim 1, characterized in that: The lens has a plurality of grooves arranged at intervals, and the plurality of grooves are configured to accommodate the light absorber; Among them, a plurality of the light absorbers are arranged in one-to-one correspondence with a plurality of the grooves.

3. The cover plate according to claim 2, characterized in that: The lens has a light incident surface and a light emitting surface that are arranged opposite to each other, and the notch of the groove is connected to the light incident surface or the light emitting surface; Wherein, the light absorber is filled in the groove.

4. The cover plate according to claim 3, characterized in that: The lens is made of glass; the light absorbing body is made of light absorbing ink.

5. The cover plate according to claim 3, characterized in that: The thickness of the lens is defined between the light incident surface and the light emitting surface, and the thickness of the lens is greater than the depth of the groove; Wherein, the difference between the thickness of the lens and the depth of the groove is less than or equal to 20 microns.

6. The cover plate according to claim 5, characterized in that: The thickness of the lens is 10-200 microns; the depth of the groove is 10-200 microns.

7. The cover plate according to claim 3, characterized in that: The ratio of the depth of the groove to the width of the groove is in the range of 0.1 to 20; wherein the width direction of the groove intersects or is perpendicular to the depth direction of the groove, and the width of the groove is less than or equal to 200 micrometers.

8. The cover plate according to claim 3, characterized in that: The grooves are randomly distributed on the lens, and the randomness of the grooves is greater than or equal to 10%; the randomness of the grooves is a comprehensive function of the randomness of the width of the grooves and the randomness of the gap between two adjacent grooves.

9. A diffraction waveguide device, characterized in that: The diffractive waveguide device comprises: A waveguide sheet and a cover plate arranged on the waveguide sheet; The cover plate includes a lens disposed on the waveguide plate, and a plurality of light absorbers spaced apart in the lens; the lens is configured to receive natural light, the natural light includes a first light ray and a second light ray, the incident angle of the first light ray is greater than a critical angle, the incident angle of the second light ray is less than the critical angle, and the critical angle is 45°-75°; The distribution of the light absorber makes the first light be blocked from passing through the lens, while the second light can pass through the lens.

10. A near-eye display device, characterized in that: The near-eye display device comprises: A frame and a diffraction waveguide device, wherein the diffraction waveguide device is mounted on the frame; the diffraction waveguide device comprises a waveguide plate and a cover plate disposed on the waveguide plate; The cover plate includes a lens disposed on the waveguide plate, and a plurality of light absorbers spaced apart in the lens; the lens is configured to receive natural light, the natural light includes a first light ray and a second light ray, the incident angle of the first light ray is greater than a critical angle, the incident angle of the second light ray is less than the critical angle, and the critical angle is 45°-75°; The distribution of the light absorber makes the first light be blocked from passing through the lens, while the second light can pass through the lens.

11. A method for manufacturing a cover plate, characterized in that: The production method comprises: Providing a lens, and forming a plurality of grooves arranged at intervals on the lens; Filling the groove with a light absorbing material to form a light absorber; The lens is configured to receive natural light, the natural light includes a first light ray and a second light ray, the incident angle of the first light ray is greater than a critical angle, the incident angle of the second light ray is less than the critical angle, and the critical angle is 45°-75°; The distribution of the light absorber makes the first light be blocked from passing through the lens, while the second light can pass through the lens.

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