Light guide module and near-eye display device
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-10-23
- Publication Date
- 2026-08-13
Smart Images
Figure CN2025129595_13082026_PF_FP_ABST
Abstract
Description
Light guide module and near-eye display device
[0001] Cross-references to related applications
[0002] This application claims priority to Chinese Patent Application No. 202510131492.6, filed on February 5, 2025, the disclosure of which is incorporated herein by reference in its entirety. Technical Field
[0003] This application relates to a light guide module and a near-eye display device. Background Technology
[0004] With the continuous development of technology, augmented reality (AR) and virtual reality (VR) technologies are gradually entering various industries. Taking AR devices as an example, users can use near-eye display devices such as AR glasses to view augmented reality scenes. For example, near-eye display devices usually require the addition of optical lenses with corrective functions, such as nearsighted or farsighted lenses, to correct the user's vision and meet the viewing needs of users with vision correction requirements. However, this leads to an increase in the weight and size of the near-eye display device, which is not conducive to the user's wearing comfort. Summary of the Invention
[0005] One or more embodiments of this disclosure provide a light guide module and a near-eye display device.
[0006] This disclosure provides a light guide module, comprising: a waveguide sheet having an insertion region and an exit region; wherein the insertion region is used to couple imaging light projected by an optomechanism into the waveguide sheet; and the exit region is used to couple the imaging light out; a first cover plate connected to a first surface of the waveguide sheet facing the optomechanism; wherein the first cover plate at least covers the portion of the waveguide sheet located in the insertion region, and the first cover plate is offset from the portion of the waveguide sheet located in the exit region; and a corrective lens connected to the first surface of the waveguide sheet facing the optomechanism, and the corrective lens at least covers the portion of the waveguide sheet located in the exit region.
[0007] In one or more embodiments, the first cover plate is connected to the waveguide sheet via a first adhesive layer; wherein the first adhesive layer is disposed near the edge of the coupling region.
[0008] In one or more embodiments, the waveguide sheet further has a waveguide region for conducting image light coupled from the coupling region; the first adhesive layer is annular and has an avoidance notch located at the edge of the coupling region toward the waveguide region.
[0009] In one or more embodiments, along the thickness direction of the waveguide sheet, the thickness d1 of the first adhesive layer satisfies the following condition: 0.05mm≤d1≤0.4mm.
[0010] In one or more embodiments, the first adhesive layer has a first edge toward the coupling region and a second edge away from the coupling region; along the direction from the first edge toward the second edge, the width w1 of the first adhesive layer satisfies the following condition: 0.4mm≤w1≤2mm.
[0011] In one or more embodiments, the orthographic projection of the corrective lens on the first surface partially coincides with the orthographic projection of the first cover plate on the first surface; the thickness of the corrective lens is greater than the thickness of the first cover plate; the corrective lens is provided with a clearance portion for accommodating the first cover plate.
[0012] In one or more embodiments, the corrective lens is bonded to the waveguide sheet via a second adhesive layer, and the corrective lens is also bonded to the first cover plate via a third adhesive layer.
[0013] In one or more embodiments, the second adhesive layer is disposed near the edge of the waveguide sheet.
[0014] In one or more embodiments, the thickness d2 of the second adhesive layer satisfies the following condition: 0.05mm≤d2≤0.4mm.
[0015] In one or more embodiments, the thickness d3 of the third adhesive layer satisfies the following condition: 0.05mm≤d3≤0.4mm.
[0016] In one or more embodiments, the surface of the first cover plate is provided with a first anti-reflection layer; the reflectivity r1 of the first anti-reflection layer satisfies the following condition: r1≤0.5%.
[0017] In one or more embodiments, a second anti-reflection layer is provided on the side of the corrective lens facing the waveguide sheet; the reflectivity r2 of the second anti-reflection layer satisfies the following condition: r2≤0.5%.
[0018] In one or more embodiments, the thickness d4 of the first cover plate satisfies the following condition: 0.3mm≤d4≤1mm.
[0019] In one or more embodiments, the surface of the corrective lens facing the waveguide sheet is planar, and the surface of the corrective lens away from the waveguide sheet is concave or convex.
[0020] This disclosure provides a near-eye display device, including: an optical engine and a light guide module as described in any of the preceding claims. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in one or more embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are one or more embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:
[0022] Figure 1 is a schematic diagram of the structure of a near-eye display device provided in one or more embodiments of the present disclosure;
[0023] Figure 2 is a schematic diagram of the waveguide sheet provided in one or more embodiments of this disclosure;
[0024] Figure 3 is a schematic diagram of the waveguide sheet and the first adhesive layer provided in one or more embodiments of this disclosure;
[0025] Figure 4 is a schematic diagram of the waveguide sheet and the first cover plate provided in one or more embodiments of this disclosure;
[0026] Figure 5 is a structural schematic diagram of the waveguide sheet, the second adhesive layer, and the first cover plate provided in one or more embodiments of this disclosure; and
[0027] Figure 6 is a schematic diagram of the assembly of the waveguide sheet, the corrective lens and the first cover plate provided in one or more embodiments of this disclosure.
[0028] Explanation of reference numerals in the attached drawings: 10-Light guide module; 101-Waveguide sheet; 101a-Coupled-in region; 101b-Coupled-out region; 101c-Waveguide region; 101d-First surface; 102-First cover plate; 103-Corrective lens; 103a-Allowing portion; 104-Second cover plate; 105-First adhesive layer; 106-Second adhesive layer; 107-Third adhesive layer; 108-Fourth adhesive layer; 20-Optic mechanism. Detailed Implementation
[0029] Embodiments of this disclosure are described in detail below, with examples of embodiments illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this disclosure, and should not be construed as limiting this disclosure.
[0030] It should be understood that the steps described in the method embodiments of this disclosure may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this disclosure is not limited in this respect.
[0031] The term "comprising" and its variations as used in this disclosure are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "one or more embodiments" means "at least one or more embodiments". Relevant definitions for other terms will be given in the description below.
[0032] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are used only to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.
[0033] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".
[0034] One or more embodiments of this disclosure can be applied to application scenarios such as Virtual Reality (VR) and Augmented Reality (AR).
[0035] Virtual Reality (VR) is a technology for creating and experiencing virtual worlds. It computationally generates a virtual environment, which is a multi-source information (virtual reality mentioned in this disclosure includes at least visual perception, and may also include auditory perception, tactile perception, motion perception, and even taste perception, olfactory perception, etc.) that realizes the fusion of virtual environment, interactive three-dimensional dynamic visual scenes and simulation of entity behavior, immersing users in the simulated virtual reality environment, and enabling applications in various virtual environments such as maps, games, videos, education, medical care, simulation, collaborative training, sales, assisted manufacturing, maintenance and repair.
[0036] Augmented Reality (AR) is a technology that calculates the camera's pose parameters in the real world (or 3D world, the real world) in real time during image capture, and adds virtual elements to the captured images based on these parameters. Virtual elements include, but are not limited to, images, videos, and 3D models. The goal of AR technology is to overlay the virtual world onto the real world on a screen for interactive experiences.
[0037] Taking AR devices as an example, AR devices are terminals that realize augmented reality effects. To improve portability, AR devices can usually be provided in the form of near-eye displays such as glasses, head-mounted displays (HMDs), and contact lenses. Of course, the form of AR devices is not limited to these, and they can be further miniaturized or enlarged as needed.
[0038] For example, AR display technology based on optical waveguides requires transmitting the small-sized display image from the optical engine through an optical waveguide to the user's eye, allowing the user to observe the display. To better protect the waveguide, the waveguide sheet is typically equipped with front and rear cover plates, which can be made of resin or optical glass. The front and rear cover plates are bonded to the waveguide sheet using OCA (Optically Clear Adhesive) or LOCA (Liquid Optical Clear Adhesive). The imaging light from the optical engine passes through the first cover plate and illuminates the waveguide sheet. It is then diffracted by a coupling grating within the waveguide, resulting in total internal reflection within the waveguide. Finally, the totally reflected imaging light exits the waveguide through an output grating and illuminates the user's eye.
[0039] For users requiring vision correction, a corrective lens can be added between the waveguide sheet and the user's eye to achieve clear imaging. The corrective lens is typically fixed to the first cover plate via magnetic attraction, snap-fit, or adhesive, specifically on the front side of the first cover plate away from the waveguide sheet. With magnetic attraction and snap-fit methods, an air gap exists between the corrective lens and the first cover plate, compromising mechanical stability and airtightness. With adhesive methods, the lens is generally bonded to the first cover plate using a full-surface adhesive tape or frame adhesive, offering better mechanical stability and airtightness. However, the addition of a corrective lens increases the weight and size of the near-eye display device, negatively impacting user comfort.
[0040] To overcome the above problems, this embodiment provides a light guide module and a near-eye display device. The first cover plate covers the coupling area of the waveguide sheet and is arranged to avoid the coupling area of the waveguide sheet. The corrective lens covers the coupling area, thereby reducing the size and weight of the light guide module, which is conducive to the miniaturization and lightweighting of the near-eye display device, and takes into account the clear imaging needs of users who need vision correction as well as wearing comfort.
[0041] The technical solutions of this disclosure and how they solve the aforementioned technical problems will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of this disclosure will now be described with reference to the accompanying drawings.
[0042] Figure 1 is a cross-sectional schematic diagram along the thickness direction of the waveguide sheet of a near-eye display device provided in one or more embodiments of this disclosure. Referring to Figure 1, the near-eye display device provided in this embodiment includes an optical engine 20 and a light guide module 10. The light guide module 10 includes a waveguide sheet 101, a first cover plate 102, and a corrective lens 103.
[0043] The waveguide 101 has a coupling-in region 101a and a coupling-out region 101b; wherein, the coupling-in region 101a is used to couple the imaging light projected by the optomechanical 20 into the waveguide 101; and the coupling-out region 101b is used to couple the imaging light out. Specifically, a coupling grating is provided in the portion of the waveguide 101 located in the coupling-in region 101a, and a coupling-out grating is provided in the portion of the waveguide 101 located in the coupling-out region 101b.
[0044] In addition, the waveguide sheet 101 is provided with a waveguide region 101c. The portion of the waveguide sheet 101 located in the waveguide region 101c is provided with a waveguide structure. The waveguide structure is used to conduct imaging light coupled from the coupling region 101a to the coupling region 101b. The waveguide structure is made of waveguide material and may specifically include a waveguide substrate and a refractive layer, etc., to conduct image light.
[0045] An optical engine 20 is correspondingly disposed in the coupling region 101a of the waveguide 101. Generally, the optical engine 20 is located in front of the coupling region 101a. The optical engine 20 refers to the microdisplay optical engine 20, which is small in size and can be used as an image generation unit to generate brightness and images, and realize the emission of image light. Specifically, the optical engine 20 can be various types of display devices with light emission, image generation and image display functions, such as Micro-LED (micron-sized light-emitting diode), DLP (Digital Light Processing, i.e., the imaging technology used in projectors and rear projection TVs), LCOS (Liquid Crystal On Silicon, also known as silicon-based liquid crystal or single-crystal silicon reflective liquid crystal, i.e., the imaging technology used in reflective liquid crystal projectors and rear projection TVs), etc.
[0046] The optical engine 20 can be a monochrome optical engine 20, so that the image displayed by the image light coupled out through different coupling gratings in the waveguide 101 corresponds to different colors. In this case, the design and manufacturing process of the corresponding optical guiding system is relatively simple. The optical engine 20 can also be a color optical engine 20, in which the image light displayed by the same coupling grating in the waveguide 101 can include multiple colors. In this case, the design and manufacturing process of the corresponding optical guiding system is more complex.
[0047] The surface of the waveguide 101 facing the optomechanical system 20 is designated as the first surface 101d. If the side of the waveguide 101 facing the optomechanical system 20 is referred to as the front, then the first surface 101d can also be called the front surface of the waveguide 101. A first cover plate 102 is connected to the first surface 101d of the waveguide 101. The first cover plate 102 at least covers the portion of the waveguide 101 located in the coupling region 101a, and the first cover plate 102 is offset from the portion of the waveguide 101 located in the coupling region 101b.
[0048] Specifically, the orthographic projection of the coupling region 101a onto the first surface 101d lies within the orthographic projection of the first cover plate 102 onto the first surface 101d. In some examples, the orthographic projection of the first cover plate 102 onto the first surface 101d completely coincides with the orthographic projection of the coupling region 101a onto the first surface 101d; and the orthographic projection of the first cover plate 102 onto the first surface 101d is offset from the orthographic projection of the coupling region 101b onto the first surface 101d. In other examples, at least one edge of the orthographic projection of the first cover plate 102 onto the first surface 101d is located outside the corresponding edge of the orthographic projection of the coupling region 101b, where "outside" refers to a direction away from the center of the coupling region 101a.
[0049] Optionally, to reduce light reflection, a first anti-reflection layer (not shown in the figure) is provided on the surface of the first cover plate 102. The first anti-reflection layer at least covers the portion of the first cover plate 102 corresponding to the coupling region 101a, allowing more imaging light to be incident on the coupling region 101a. The first anti-reflection layer may be disposed on the surface of the first cover plate 102 facing away from the waveguide sheet 101, and / or the first anti-reflection layer may also be disposed on the surface of the first cover plate 102 facing the waveguide sheet 101.
[0050] The reflectivity r of the first antireflection layer satisfies the following condition: r1 ≤ 0.5%. For example, the reflectivity r1 of the first antireflection layer can be 0.5%, 0.45%, 0.4%, 0.35%, 0.3%, 0.25%, 0.2%, 0.15%, 0.1%, or 0.05%, or any two of the above.
[0051] Optionally, in order to balance the miniaturization and weight reduction of the light guide module 10 with the protective effect of the first cover plate 102, the thickness d4 of the first cover plate 102 satisfies the following condition: 0.3mm ≤ d4 ≤ 1mm. For example, the thickness d4 of the first cover plate 102 can be 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, or 1mm, or any two of the above thicknesses.
[0052] A corrective lens 103 is also connected to the first surface 101d of the waveguide 101 facing the optical engine 20. The corrective lens 103 is disposed at least covering the portion of the waveguide 101 located in the coupling region 101b. Specifically, the orthographic projection of the coupling region 101b on the first surface 101d lies within the orthographic projection of the corrective lens 103 on the first surface 101d. The corrective lens 103 is used to achieve vision correction to meet the needs of users with vision problems such as myopia, hyperopia, or astigmatism.
[0053] Optionally, the surface of the corrective lens 103 facing the waveguide plate 101 is flat, facilitating the connection between the corrective lens 103 and the waveguide plate 101. The surface of the corrective lens 103 facing away from the waveguide plate 101 is concave or convex, which can be set according to the user's vision correction needs. It can be understood that the power and other parameters of the corrective lens 103 can be set according to the user's vision condition.
[0054] The corrective lens 103 has a second anti-reflective layer (not shown in the figure) on the side facing the waveguide plate 101, allowing more imaging light to enter the corrective lens 103, thereby improving image quality. The reflectivity r2 of the second anti-reflective layer satisfies the following condition: r2 ≤ 0.5%. For example, the reflectivity r2 of the second anti-reflective layer can be 0.5%, 0.45%, 0.4%, 0.35%, 0.3%, 0.25%, 0.2%, 0.15%, 0.1%, or 0.05%, or any two of the above.
[0055] Additionally, the light guide module 10 may further include a second cover plate 104, which is connected to the second surface of the waveguide sheet 101. The second surface of the waveguide sheet 101 is the surface of the waveguide sheet 101 facing away from the optical engine 20, and the second surface and the first surface 101d are spaced apart along the thickness direction of the waveguide sheet 101. The material of the second cover plate 104 may be the same as or similar to that of the first cover plate 102. The thickness of the second cover plate 104 may be slightly greater than the thickness of the first cover plate 102, depending on actual needs. The second cover plate 104 can be connected to the waveguide sheet 101 via a fourth adhesive layer 108.
[0056] The light guide module 10 provided in this embodiment includes a waveguide 101, a first cover plate 102, and a corrective lens 103. The waveguide 101 has a coupling-in region 101a and a coupling-out region 101b. The coupling-in region 101a is used to couple the imaging light projected by the optical engine 20 into the waveguide 101; the coupling-out region 101b is used to couple the imaging light out. The first cover plate 102 is connected to the first surface 101d of the waveguide 101 facing the optical engine 20. The first cover plate 102 at least covers the waveguide 101 located in the coupling-in region 101a. The first cover plate 102 and the waveguide 101 located in the coupling region 101b are partially offset; the corrective lens 103 is connected to the first surface 101d of the waveguide 101 facing the optical engine 20, and the corrective lens 103 is arranged to at least cover the portion of the waveguide 101 located in the coupling region 101b. In this way, the volume and weight of the light guide module 10 can be reduced, which is conducive to the miniaturization and weight reduction of near-eye display devices, while taking into account the clear imaging needs of users who need vision correction and wearing comfort.
[0057] In one or more embodiments, the first cover plate 102 is connected to the waveguide sheet 101 via a first adhesive layer 105; wherein the first adhesive layer 105 is disposed near the edge of the coupling region 101a to minimize the influence of the first adhesive layer 105 on the imaging light.
[0058] Figure 2 is a schematic diagram of the front structure of a waveguide sheet provided in one or more embodiments of this disclosure. Referring to Figure 2, exemplarily, the coupling region 101a is disposed on one side near the waveguide sheet 101, or the coupling region 101a is disposed on two adjacent sides of the waveguide sheet 101. Referring to Figure 3, in order to reduce the influence of the first adhesive layer 105 on the imaging light, the first adhesive layer 105 is disposed at the edge of the coupling region 101a. The first adhesive layer 105 can be formed by dispensing or bonding. The specific material used for the first adhesive layer 105 can be selected according to actual needs. Referring to Figure 4, the first cover plate 102 is connected to the waveguide sheet 101 through the first adhesive layer 105; the position of the first cover plate 102 corresponds to the position of the coupling region 101a.
[0059] For example, the waveguide 101 is generally rectangular, and a coupling region 101a is formed near one of its apex corners. The coupling region 101a is generally rectangular. A first adhesive layer 105 is formed near the edge of the coupling region 101a by dispensing or bonding, thereby connecting the waveguide 101 to the first cover plate 102 through the first adhesive layer 105.
[0060] Optionally, the shape of the first cover plate 102 can be adapted to the shape of the coupling region 101a so that the first cover plate 102 covers the coupling region 101a. For example, when the coupling region 101a is rectangular, the first cover plate 102 is also rectangular; when the coupling region 101a is circular, the first cover plate 102 is also circular.
[0061] Optionally, as shown in Figure 3, the first adhesive layer 105 is annular, and its specific shape can be adapted to the shape of the coupling region 101a or the first cover plate 102; for example, the first adhesive layer 105 can be circular or rectangular. The first adhesive layer 105 is provided with an avoidance notch, which is located at the edge of the coupling region 101a facing the waveguide region 101c, so as to prevent the first adhesive layer 105 from interfering with the transmission of imaging light.
[0062] For example, the coupling region 101a is rectangular, one of the long edges of the coupling region 101a is part of the edge of the waveguide sheet 101, and one of the wide edges of the coupling region 101a is part of the edge of the waveguide sheet 101. A first adhesive layer 105 is provided at the aforementioned edge of the coupling region 101a; at least part of the edge of the coupling region 101a adjacent to the waveguide region 101c is not provided with the first adhesive layer 105.
[0063] In this case, the portion of the edge of the coupling region 101a adjacent to the waveguide region 101c that does not have the first adhesive layer 105 forms an avoidance gap; for example, the entire edge of the coupling region 101a adjacent to the waveguide region 101c does not have the first adhesive layer 105; or, for another example, a portion of the edge of the coupling region 101a adjacent to the waveguide region 101c does not have the first adhesive layer 105, while another portion has the first adhesive layer 105, in order to improve the connection reliability between the first cover plate 102 and the waveguide sheet 101.
[0064] In some examples, to balance miniaturization of the light guide module 10 and the reliability of the connection between the first cover plate 102 and the waveguide sheet 101, the thickness d1 of the first adhesive layer 105 along the thickness direction of the waveguide sheet 101 (the up-down direction in FIG. 1) satisfies the following condition: 0.05mm ≤ d1 ≤ 0.4mm. For example, the thickness d1 of the first adhesive layer 105 can be 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, or 0.4mm, or any two of the above.
[0065] In some examples, as shown in Figure 3, to balance the miniaturization of the light guide module 10 and the reliability of the connection between the first cover plate 102 and the waveguide sheet 101, the first adhesive layer 105 has a first edge facing the coupling region 101a and a second edge away from the coupling region 101a. Along the direction from the first edge to the second edge, the first adhesive layer 105 has a preset width; or, in other words, the shortest straight-line distance between the first edge and the corresponding second edge of the first adhesive layer 105 is the width of the first adhesive layer 105. The width w1 of the first adhesive layer 105 satisfies the following condition: 0.4mm ≤ w1 ≤ 2mm.
[0066] For example, the width w1 of the first adhesive layer 105 can be 0.4 mm, 0.8 mm, 1.2 mm, 1.6 mm, or 2.0 mm, or any two of these values. The width of the first adhesive layer 105 refers to the width of the first adhesive layer 105 near one of the edges of the coupling region 101a. The widths of the first adhesive layers 105 near different edges of the coupling region 101a can be the same or different.
[0067] Referring again to Figure 1, in one or more embodiments, the orthographic projection of the corrective lens 103 onto the first surface 101d partially coincides with the orthographic projection of the first cover plate 102 onto the first surface 101d. For example, a portion of the corrective lens 103 extends above the coupling region 101a; or, a portion of the first cover plate 102 extends above the waveguide region 101c, and a portion of the corrective lens 103 also extends above the waveguide region 101c.
[0068] The thickness of the corrective lens 103 is greater than the thickness of the first cover plate 102. The corrective lens 103 is provided with a clearance portion 103a, which is used to accommodate the first cover plate 102. Since the thickness of the corrective lens 103 is usually greater than the thickness of the first cover plate 102, the portion of the corrective lens 103 corresponding to the first cover plate 102 can be made with an ultra-precision cutting process to form the clearance portion 103a. The clearance portion 103a can be groove-shaped, and the shape of the space defined by the clearance portion 103a is consistent with the shape of the corresponding portion of the first cover plate 102. The length of the space defined by the clearance portion 103a is adapted to the size of the corresponding portion of the first cover plate 102. For example, the depth of the space defined by the clearance portion 103a is slightly greater than the sum of the thickness of the first cover plate 102 and the thickness of the first adhesive layer 105. Adhesive can be filled between the wall of the clearance portion 103a and the first cover plate 102.
[0069] Of course, in other embodiments, the orthographic projection of the corrective lens 103 on the first surface 101d and the orthographic projection of the first cover plate 102 on the first surface 101d may not coincide, and the orthographic projections of the corrective lens 103 and the first cover plate 102 on the first surface 101d can completely cover the first surface 101d of the waveguide sheet 101. The side of the corrective lens 103 and the side of the first cover plate 102 can be bonded and fixed using adhesive. The thickness of the corrective lens 103 and the thickness of the first cover plate 102 can be set according to actual needs.
[0070] Referring to Figures 1, 5, and 6, in one or more embodiments, the corrective lens 103 is bonded to the waveguide sheet 101 via a second adhesive layer 106. For example, the second adhesive layer 106 can be formed near the edge of the waveguide sheet 101 by dispensing or bonding, thereby connecting the corrective lens 103 and the waveguide sheet 101 through the second adhesive layer 106. During the formation of the second adhesive layer 106, the location of the first cover plate 102 must be avoided.
[0071] In some examples, to balance miniaturization of the light guide module 10 and the reliability of the connection between the corrective lens 103 and the waveguide sheet 101, the thickness d2 of the second adhesive layer 106 along the thickness direction of the waveguide sheet 101 satisfies the following condition: 0.05mm ≤ d2 ≤ 0.4mm. For example, the thickness d2 of the second adhesive layer 106 can be 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, or 0.4mm, or any two of the above.
[0072] Optionally, the thickness of the second adhesive layer 106 can be slightly greater than the thickness of the first adhesive layer 105, in order to balance the miniaturization and weight reduction of the light guide module 10, as well as the connection reliability between the corrective lens 103 and the waveguide sheet 101. For example, the thickness of the first adhesive layer 105 can be 0.1mm, 0.15mm, or 0.2mm, and the thickness of the second adhesive layer 106 can be 0.25mm, 0.3mm, 0.35mm, or 0.4mm.
[0073] In some examples, as shown in Figure 5, to balance miniaturization of the light guide module 10 and the reliability of the connection between the corrective lens 103 and the waveguide 101, the second adhesive layer 106 has a third edge facing the center of the waveguide 101 and a fourth edge facing away from the center of the waveguide 101. Along the direction from the third edge to the fourth edge, the second adhesive layer 106 has a preset width; in other words, the minimum straight-line distance between the third edge and the fourth edge is the width of the second adhesive layer 106. The width w2 of the second adhesive layer 106 satisfies the following condition: 0.4mm ≤ w2 ≤ 2mm. For example, the width w2 of the second adhesive layer 106 can be 0.4mm, 0.8mm, 1.2mm, 1.6mm, or 2.0mm, or any two of these values. The width of the second adhesive layer 106 refers to the width of the second adhesive layer 106 closest to one edge of the waveguide 101. The width of the first adhesive layer 105 near different edges of the waveguide 101 can be the same or different.
[0074] Optionally, the width of the second adhesive layer 106 may be slightly larger than the width of the first adhesive layer 105, in order to balance the miniaturization and weight reduction of the light guide module 10, as well as the connection reliability between the corrective lens 103 and the waveguide sheet 101.
[0075] Referring to Figure 1, in one or more embodiments, the corrective lens 103 is also bonded to the first cover plate 102 via a third adhesive layer 107. For example, the third adhesive layer 107 may be formed in the area near the edge of the first cover plate 102 by dispensing or bonding, thereby connecting the corrective lens 103 and the first cover plate 102 via the third adhesive layer 107.
[0076] In some examples, to balance miniaturization of the light guide module 10 and the reliability of the connection between the corrective lens 103 and the first cover plate 102, the thickness d3 of the third adhesive layer 107 along the thickness direction of the waveguide sheet 101 satisfies the following condition: 0.05mm ≤ d3 ≤ 0.4mm. For example, the thickness d3 of the third adhesive layer 107 can be 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, or 0.4mm, or any two of the above.
[0077] Optionally, the thickness of the third adhesive layer 107 can be greater than or equal to the thickness of the first adhesive layer 105, in order to balance the miniaturization and weight reduction of the light guide module 10, as well as the reliability of the connection between the corrective lens 103 and the first cover plate 102. For example, the thickness of the third adhesive layer 107 can be equal to the thickness of the second adhesive layer 106, or the thickness of the third adhesive layer 107 can be greater than the thickness of the first adhesive layer 105 but less than the thickness of the first adhesive layer 105. It is understood that the thicknesses of the first adhesive layer 105, the second adhesive layer 106, and the third adhesive layer 107 can be set according to actual needs.
[0078] In some examples, to balance miniaturization of the light guide module 10 and reliable connection between the corrective lens 103 and the first cover plate 102, the third adhesive layer 107 has a fifth edge facing the center of the first cover plate 102 and a sixth edge facing away from the center of the first cover plate 102. Along the direction from the fifth edge to the sixth edge, the width w3 of the third adhesive layer 107 satisfies the following condition: 0.4mm ≤ w3 ≤ 2mm. For example, the width w3 of the third adhesive layer 107 can be 0.4mm, 0.8mm, 1.2mm, 1.6mm, or 2.0mm, or any two of these values. The width of the third adhesive layer 107 refers to the width of the third adhesive layer 107 closest to one edge of the first cover plate 102. The widths of the third adhesive layer 107 closest to different edges of the first cover plate 102 can be the same or different.
[0079] Optionally, the width of the third adhesive layer 107 can be slightly larger than the width of the first adhesive layer 105, in order to balance the miniaturization and weight reduction of the light guide module 10, as well as the reliability of the connection between the corrective lens 103 and the first cover plate 102. It is understood that the widths of the first adhesive layer 105, the second adhesive layer 106, and the third adhesive layer 107 can be set according to actual needs.
[0080] In this example, the depth of the space defined by the clearance portion 103a of the corrective lens 103 can be determined based on the thickness of the first cover plate 102, the thickness of the first adhesive layer 105, the thickness of the second adhesive layer 106, and the thickness of the third adhesive layer 107. For example, when the thickness of the first adhesive layer 105 is equal to the thickness of the second adhesive layer 106, the depth of the space defined by the clearance portion 103a can be the sum of the thickness of the first cover plate 102 and the thickness of the third adhesive layer 107.
[0081] The fabrication process of the light guide module 10 in this embodiment is as follows: As shown in Figure 2, take the waveguide sheet 101; as shown in Figure 3, apply adhesive or OCA adhesive to a portion of the edge of the coupling region 101a of the waveguide sheet 101 to form a first adhesive layer 105. The width of the first adhesive layer 105 is between 0.4-2 mm, and the thickness is between 0.05-0.4 mm; referring to Figure 4, attach the first cover plate 102 so that the first cover plate 102 is connected to the waveguide sheet 101 through the first adhesive layer 105; the correction lens is then attached to the first cover plate 102. The overlapping area is designed with ultra-precision cutting to create a clearance section 103a. Referring to Figure 5, the area not covered by the first cover plate 102 is coated with adhesive or OCA adhesive to form a second adhesive layer 106, and a third adhesive layer 107 is formed on the first cover plate 102 by adhesive or OCA adhesive. Referring to Figure 6, the corrective lens 103 is attached, so that the corrective lens 103 is connected to the waveguide sheet 101 through the second adhesive layer 106, and the corrective lens 103 is connected to the first cover plate 102 through the third adhesive layer 107. The surface of the first cover plate 102 is processed with an anti-reflective layer, with a surface reflectivity of less than or equal to 0.5%. The side of the corrective lens 103 closest to the waveguide sheet 101 is flat and also processed with an anti-reflective layer, with a surface reflectivity of less than or equal to 0.5%.
[0082] In this embodiment, the imaging light emitted by the optomechanical system 20 is transmitted through the first cover plate 102 and illuminates the coupling region 101a of the waveguide 101. The coupling grating of the coupling region 101a diffracts the imaging light and illuminates the waveguide 101 for total internal reflection. The totally internally reflected imaging light passes through the deflection grating of the waveguide 101's conduction region and the coupling grating of the coupling region 101b and exits from the waveguide 101. The exited imaging light passes through the corrective lens 103 and directly illuminates the user's eye. This embodiment uses a composite bonding process of the corrective lens 103 and the first cover plate 102 to replace the first cover plate 102 in areas other than the coupling region 101a. This saves the thickness of the first cover plate 102 and the corresponding adhesive layer, thereby reducing the size and weight of the light guide module 10. This overcomes the problem that the size and weight of the light guide module 10, which is compatible with refractive power, increases due to the need to install the corrective lens 103.
[0083] This embodiment also provides a light guide module 10. The structure, function and implementation of the light guide module 10 can be the same as or similar to the light guide module 10 in any of the foregoing embodiments. This embodiment will not repeat the details here.
[0084] In the description of this embodiment, it should be understood that the terms "thickness", "width", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.
[0085] In this disclosure, unless otherwise explicitly specified or limited in the embodiments, the terms "installation," "connection," "joining," and "fixing," etc., appearing in the embodiments should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral part; it can also be a mechanical connection, an electrical connection, etc. Of course, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication between two components, or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure based on the specific implementation.
[0086] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0087] In the accompanying drawings, the size of constituent elements, the thickness of layers, or areas may sometimes be exaggerated for clarity. Therefore, any implementation of this disclosure is not necessarily limited to the dimensions shown in the drawings, and the shapes and sizes of the components in the drawings do not reflect true proportions. Furthermore, the drawings schematically illustrate ideal examples, and any implementation of this disclosure is not limited to the shapes or values shown in the drawings.
[0088] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.
Claims
1. A light guide module, comprising: A waveguide sheet having an insertion region and an exit region; wherein the insertion region is used to couple imaging light projected by an optomechanical system into the waveguide sheet; and the exit region is used to couple the imaging light out. A first cover plate is connected to a first surface of the waveguide sheet facing the optomechanism; wherein the first cover plate covers at least the portion of the waveguide sheet located in the coupling region, and the first cover plate is offset from the portion of the waveguide sheet located in the coupling region. A corrective lens is attached to a first surface of the waveguide facing the optomechanism, and the corrective lens is disposed at least covering a portion of the waveguide located in the coupling region.
2. The light guide module according to claim 1, wherein, The first cover plate is connected to the waveguide sheet via a first adhesive layer; wherein the first adhesive layer is disposed near the edge of the coupling region.
3. The light guide module according to claim 2, wherein, The waveguide sheet also has a waveguide region for conducting image light coupled in from the coupling region; The first adhesive layer is annular and has a clearance notch located at the edge of the coupling region toward the waveguide region.
4. The light guide module according to claim 2 or 3, wherein, Along the thickness direction of the waveguide sheet, the thickness d1 of the first adhesive layer satisfies the following condition: 0.05mm≤d1≤0.4mm.
5. The light guide module according to any one of claims 2-4, wherein, The first adhesive layer has a first edge facing the coupling region and a second edge facing away from the coupling region; along the direction from the first edge to the second edge, the width w1 of the first adhesive layer satisfies the following condition: 0.4mm≤w1≤2mm.
6. The light guide module according to any one of claims 1-5, wherein, The orthographic projection of the corrective lens on the first surface partially overlaps with the orthographic projection of the first cover plate on the first surface. The thickness of the corrective lens is greater than the thickness of the first cover plate, and the corrective lens is provided with a clearance portion for accommodating the first cover plate.
7. The light guide module according to claim 6, wherein, The corrective lens is bonded to the waveguide sheet via a second adhesive layer, and the corrective lens is also bonded to the first cover plate via a third adhesive layer.
8. The light guide module according to claim 7, wherein, The second adhesive layer is disposed near the edge of the waveguide sheet.
9. The light guide module according to claim 7 or 8, wherein, The thickness d2 of the second adhesive layer satisfies the following condition: 0.05mm≤d2≤0.4mm; And / or, The thickness d3 of the third adhesive layer satisfies the following condition: 0.05mm≤d3≤0.4mm.
10. The light guide module according to any one of claims 1-9, wherein, The surface of the first cover plate is provided with a first anti-reflection layer; the reflectivity r1 of the first anti-reflection layer satisfies the following condition: r1≤0.5％； And / or, A second anti-reflection layer is provided on the side of the corrective lens facing the waveguide sheet; the reflectivity r2 of the second anti-reflection layer satisfies the following condition: r2≤0.5％。 11. The light guide module according to any one of claims 1-10, wherein, The thickness d4 of the first cover plate satisfies the following condition: 0.3mm≤d4≤1mm.
12. The light guide module according to any one of claims 1-11, wherein, The surface of the corrective lens facing the waveguide sheet is flat, and the surface of the corrective lens away from the waveguide sheet is concave or convex.
13. A near-eye display device, comprising: Optical engine and light guide module as described in any one of claims 1 to 12.