A light guide device and an optical display device

Abstract

This application provides a light guide device and an optical display device; wherein, the light guide device includes a photochromic film layer, a grating layer, a waveguide layer, and a protective layer stacked from the world side to the human eye side; the grating layer includes an insertion grating and an exit grating, wherein the exit grating is disposed on the world side surface of the waveguide layer and located between the waveguide layer and the photochromic film layer; an optical filling layer is formed between the grating layer and the photochromic film layer, and the optical filling layer at least covers the exit grating, and the refractive index of the optical filling layer is... n 1 is lower than the refractive index of the grating layer n 2, and 0.2≤ n 2- n 1≤0.5; The protective layer is located on the optomechanical side of the waveguide layer and is used to isolate the external optomechanical system from the waveguide layer.

Description

Technical Field

[0001] This application relates to the field of near-eye optical display technology, and more specifically, to a light guide device and an optical display device. Background Technology

[0002] In the field of AR (Augmented Reality), diffractive waveguide technology has become a key means to achieve lightweight and portable terminal displays, and is widely used in various AR devices. To meet users' demands for device portability, resin materials, due to their advantages of being lightweight, highly malleable, and having low processing costs, are widely used as substrates and protective materials for fabricating optical waveguides. However, despite the excellent performance of resin materials in terms of lightweighting, traditional resin waveguide architectures have revealed a series of problems that urgently need to be solved in applications.

[0003] Firstly, traditional resin waveguide architectures face significant challenges in protecting the grating layer. Because resin is inherently soft, and the protective layer is often bonded to the grating layer using a frame-mount method, this design makes the protective layer highly susceptible to deformation during daily use and cleaning. Once deformed, the grating may be crushed or damaged, negatively impacting the display quality and lifespan of the device.

[0004] Secondly, controlling the air gap between the resin protective layer and the resin waveguide layer is also a technical challenge. This gap is typically small, making it difficult to precisely control the surface quality of the resin protective layer. To prevent the resin protective layer from contacting the grating layer due to deformation, traditional architectures often require increasing the thickness of the resin protective layer. However, this approach contradicts the original intention of lightweight design, as it not only increases the overall weight of the device but may also affect its portability and user experience.

[0005] More importantly, traditional resin waveguide architectures have significant shortcomings in optical performance. Particularly in key indicators such as the invisibility of rainbow patterns, gratings, and color uniformity, traditional architectures struggle to meet the requirements of high-end applications and professional fields. These issues not only affect the display effects and visual experience of AR devices but also limit their wider adoption in broader markets and application scenarios. Summary of the Invention

[0006] The purpose of this application is to provide a new technical solution for light guide devices and optical display equipment.

[0007] In a first aspect, this application provides a light guiding device, which includes a photochromic film layer, a grating layer, a waveguide layer and a protective layer stacked together from the world side to the human eye side;

[0008] The grating layer includes an input grating and an output grating, wherein the output grating is disposed on the world side surface of the waveguide layer and located between the waveguide layer and the color-changing film layer;

[0009] An optical filling layer is formed between the grating layer and the photochromic film layer, and the optical filling layer at least covers the coupling grating, wherein the refractive index of the optical filling layer is... n 1 is lower than the refractive index of the grating layer n 2, and 0.2≤ n 2- n 1≤0.5;

[0010] The protective layer is located on the optomechanical side of the waveguide layer and is used to isolate the external optomechanical components from the waveguide layer.

[0011] Optionally, the grating layer further includes a bend grating, which is located on the same side of the waveguide layer as the coupling grating, and the optical filling layer also covers the bend grating.

[0012] Optionally, the refractive index of the grating layer n 2 and the refractive index of the waveguide layer n 3. Satisfy: | n 2- n 3|≤0.5.

[0013] Optionally, the coupling grating adopts a reflective coupling structure, which is disposed on the world side surface of the waveguide layer and located between the color-changing film layer and the waveguide layer, and a reflective coating layer is covered on the surface of the coupling grating.

[0014] Optionally, the height of the optical filling layer is lower than the grating height of the coupled grating.

[0015] Optionally, the reflective coating layer is a single-layer metal film, a combination of multiple dielectric films and metal films, or a multiple dielectric film.

[0016] Optionally, the coupling grating is a transmission coupling structure, disposed on the human eye side surface of the waveguide layer, and is located on two opposite surfaces of the waveguide layer, respectively, to directly transmit and couple the outgoing light of the optomechanism into the waveguide layer, wherein the optomechanism and the human eye are located on the same side of the waveguide layer.

[0017] Optionally, the color-changing sheet layer has a curved structure, and its curved structure is adapted to the contour of the grating layer to provide curved support for the grating layer;

[0018] The edge region of the color-changing film layer is fixedly connected to the edge region of the waveguide layer to form a closed optical cavity structure.

[0019] Optionally, the color-changing film layer includes:

[0020] A substrate layer composed of electrochromic or photochromic materials; or,

[0021] A resin or glass substrate, the surface of which is coated with a photosensitive material layer.

[0022] Optionally, the optical filling layer is formed on the surface of the waveguide layer near the photochromic film layer by spin coating.

[0023] Optionally, the thickness T of the protective layer is 0.05mm ≤ T ≤ 0.5mm.

[0024] Secondly, this application provides an optical display device, the optical display device comprising:

[0025] Optical mechanism; and

[0026] The light guide device as described in the first aspect;

[0027] The optical engine is located on one side of the protective layer of the light guide device.

[0028] The beneficial effects of this application are as follows:

[0029] The light guide device provided in this application optimizes optical performance by introducing a low-refractive-index optical filling layer between the grating layer and the color-changing film layer. The refractive index of this optical filling layer is lower than that of the grating layer, and the difference in refractive index between the two is controlled between 0.2 and 0.5. This design effectively reduces the occurrence of rainbow patterns, improves the invisibility of the grating, and enhances the color uniformity of the displayed image, thereby improving the optical performance of the light guide device and providing users with a clearer and more realistic visual experience.

[0030] In terms of grating protection, an optical filler layer covers the coupling grating, providing additional protection for the grating layer. During use, this effectively enhances the grating's abrasion resistance, significantly reducing the risk of damage to the grating layer due to wiping operations, extending the grating layer's lifespan, and ensuring the stability of the light guide device's performance.

[0031] In terms of structural layout and lightweight design, the light guide device features a layered arrangement of a photochromic film, a grating layer, a waveguide layer, and a protective layer, stacked sequentially from the world side to the human eye side. This compact stacked structure lays the foundation for a lighter AR optical display device. Notably, the protective layer is positioned on the optomechanical side of the waveguide layer, and its function has shifted. It primarily isolates the external optomechanical system from the waveguide layer, rather than serving as a traditional protective grating layer. This change in functional focus reduces the precision requirements for the protective layer's shape. Consequently, the protective layer's thickness can be further reduced, simplifying the manufacturing process, lowering production costs, and reducing the overall weight of the light guide device. This design strongly supports the design of lighter and more portable AR devices, significantly improving user comfort and convenience when using AR optical display devices.

[0032] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0033] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0034] Figure 1 This is a schematic diagram of a traditional resin waveguide architecture;

[0035] Figure 2 This is one of the structural schematic diagrams of the light guide device provided in the embodiments of this application;

[0036] Figure 3 A second schematic diagram of the structure of the light guide device provided in the embodiments of this application (excluding the color-changing film layer and the protective layer).

[0037] Figure 4 The third schematic diagram of the structure of the light guide device provided in the embodiment of this application (excluding the color-changing film layer and the protective layer).

[0038] Figure 5 The fourth schematic diagram of the structure of the light guide device provided in the embodiments of this application (excluding the color-changing film layer and the protective layer).

[0039] Figure 6 Fifth schematic diagram of the structure of the light guide device provided in the embodiments of this application (excluding the color-changing film layer and the protective layer).

[0040] Figure 7 This is the sixth schematic diagram of the structure of the light guide device provided in the embodiments of this application;

[0041] Figure 8 Seventh schematic diagram of the structure of the light guide device provided in the embodiments of this application (excluding the color-changing film layer and the protective layer).

[0042] Figure 9 Eighth schematic diagram of the structure of the light guide device provided in the embodiments of this application (excluding the color-changing film layer and the protective layer).

[0043] Figure 10 The ninth schematic diagram of the structure of the light guide device provided in the embodiments of this application (excluding the color-changing film layer and the protective layer).

[0044] Explanation of reference numerals in the attached figures:

[0045] 1. Color-changing film;

[0046] 2. Grating layer; 21. Coupled-in grating; 22. Coupled-out grating; 23. Turning grating;

[0047] 3. Waveguide layer; 4. Protective layer; 5. Optical filling layer; 51. Protruding structure; 6. Reflective coating layer;

[0048] A. Optical mechanism; 01. Human eye. Detailed Implementation

[0049] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0050] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0051] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0052] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0053] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0054] The light guide device, its fabrication method, and the optical display device provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0055] According to one embodiment of this application, a light guide device is provided, see [link to relevant documentation]. Figure 2 and Figure 7The light guiding device comprises, from the world side to the human eye side, a photochromic layer 1, a grating layer 2, a waveguide layer 3, and a protective layer 4, stacked sequentially. The grating layer 2 includes an insertion grating 21 and an exit grating 22, wherein the exit grating 22 is disposed on the world-side surface of the waveguide layer 3 and located between the waveguide layer 3 and the photochromic layer 1. An optical filling layer 5 is formed between the grating layer 2 and the photochromic layer 1, and the optical filling layer 5 at least covers the exit grating 22. The refractive index of the optical filling layer 5 is... n 1. The refractive index is lower than that of the grating layer 2 n 2, 0.2≤ n 2- n 1≤0.5; The protective layer 4 is located on the optomechanical side of the waveguide layer 3 and is used to isolate the external optomechanical A from the waveguide layer 3.

[0056] The light guide devices provided in this application, such as diffractive waveguide devices, can be widely used in the augmented reality (AR) field as key optical display components in various AR optical display devices. These light guide devices, with their optimized architecture design and material selection, effectively solve problems such as deformation, surface shape control, and poor optical performance inherent in traditional resin waveguide architectures, providing a lighter and higher-performance near-eye display solution for AR optical display devices. Specifically, the light guide devices provided in this application can be applied to smart wearable devices such as AR glasses and AR helmets. With their superior optical performance and lightweight design, they bring users a clear and comfortable visual experience, powerfully promoting the expansion and application of AR display technology in multiple fields.

[0057] See Figure 1 Traditional resin waveguide architectures typically employ a protective layer 4 (cover) to protect the grating layer 2 on the waveguide layer 3 via a frame-mount method. Here, the protective layer 4 is a resin protective layer. However, this architecture has revealed several problems in practical applications:

[0058] (1) Deformation risk: The resin material is soft, and the various functional gratings (such as the input grating, output grating, etc.) are framed with the protective layer 4, with air filling in between. During the cleaning process, the protective layer 4 is very prone to deformation, which may crush the grating layer 2 and seriously affect the performance of the device.

[0059] (2) The surface shape of the protective layer 4 is difficult to control: The air gap between the protective layer 4 and the waveguide layer 3 (also made of resin) is extremely small, only about 100 μm. In addition, the softness of the resin material makes it difficult to accurately control the surface shape quality of the protective layer 4. In order to prevent the protective layer 4 from contacting the grating layer 2 due to deformation, its thickness usually needs to be increased, which undoubtedly increases the overall weight and volume of the device.

[0060] (3) Poor optical performance: This simple resin waveguide architecture has poor optical performance, especially in terms of rainbow control, grating invisibility and color uniformity.

[0061] To address the problems of traditional resin waveguide architectures, this application proposes a novel waveguide architecture. This architecture effectively solves core issues such as the difficulty in controlling the deformation and surface shape of the protective layer, as well as the poor optical performance of the light guide device. It not only significantly improves the overall performance of the light guide device but also enhances its reliability, providing a higher-quality and more efficient display solution for applications such as AR optical display devices. The structural and performance advantages of the light guide device provided in this application will be described in detail below.

[0062] The light guide device provided in this embodiment includes a color-changing sheet layer 1, see [link to embodiment]. Figure 2 and Figure 7 The color-changing layer 1 is located on the outermost side of the light guide device, facing the world. Its functions include adjusting or filtering ambient light. This design not only helps optimize the visual experience but also automatically adjusts according to changes in ambient light, creating a more comfortable viewing environment for users.

[0063] As the outermost structure of the light guide device, the color-changing layer 1 is adjacent to the underlying grating layer 2. Its adjustment or filtering effect on ambient light affects the incident conditions of light on the grating layer 2, thereby indirectly affecting the visibility of the grating. At the same time, by adjusting the ambient light, the color-changing layer 1 can also improve the color uniformity of the light guide device, making the entire light guide device more consistent in displaying colors.

[0064] The light guide device provided in this embodiment includes a grating layer 2, see [link]. Figure 2 and Figure 7 The grating layer 2 is designed with, for example, an input grating 21 and an output grating 22. Each functional grating plays a key role in the transmission and coupling of light.

[0065] The coupling grating 21 is responsible for coupling external light into the waveguide layer 3. The coupling grating 22 couples light out of the waveguide layer 3.

[0066] In the structural layout of the light guide device, the coupling grating 22 is disposed between the photochromic layer 1 and the waveguide layer 3. This layout optimizes the light transmission path, improves the efficiency of light coupling, and ensures the overall performance of the light guide device.

[0067] Optionally, the grating layer 2 may further include a deflection grating 23. The deflection grating 23 is used to change the propagation direction of light within the waveguide layer 3 to achieve a more flexible optical path design.

[0068] It should be noted that the transition grating 23 can be selectively configured as needed. That is, the light guide device provided in this application embodiment may only have the input grating 21 and the output grating 22 configured, or it may have the input grating 21, the output grating 22 and the transition grating 23 configured simultaneously.

[0069] The refractive index of the grating layer 2 n 2 is one of the key parameters affecting the optical performance of light guide devices. To further optimize optical performance, this application specifically designs an optical filling layer 5 with a specific refractive index (the refractive index of the optical filling layer 5 is...). n 1) and it is placed between the grating layer 2 and the photochromic layer 1. The optical filling layer 5 must at least cover the coupling grating 22, which can serve to bond the grating layer 2 and the photochromic layer 1, and also optimize the overall optical performance through its specific refractive index characteristics. Of course, when the grating layer 2 is provided with a transition grating 23, the optical filling layer 5 also covers the transition grating 23.

[0070] Specifically, the refractive index of the optical filling layer 5 n 1 is designed to have a lower refractive index than grating layer 2. n 2. Furthermore, the refractive index difference between the two is controlled within the range of 0.2 to 0.5. This design helps to reduce rainbow effects and improve the color uniformity of displayed images, thereby providing users with a clearer and more comfortable visual experience.

[0071] Optionally, the refractive index difference between the optical filling layer 5 and the grating layer 2 can be set to 0.2, 0.3, 0.4 or 0.5, which can be adjusted according to different optical requirements and design goals in practical applications.

[0072] In this application, a preferred optical parameter design is that the refractive index of the optical filling layer 5 is... n 1. The refractive index is lower than that of the grating layer 2 n 2, and 0.2≤ n 2- n 1≤0.4. This design helps to better reduce rainbow effects and improve the color uniformity of displayed images.

[0073] It should be noted that the refractive index of the grating layer 2 is... n 2. The grating layer 2 includes a coupling-in grating 21 and a coupling-out grating 22, and optionally includes a transition grating 23. The refractive index of the coupling-in grating 21, the coupling-out grating 22, and the transition grating 23 is... n 2.

[0074] The light guiding device provided in this embodiment includes a waveguide layer 3, see [link]. Figure 2 and Figure 7The waveguide layer 3, for example, can be made of resin material and is located between the grating layer 2 and the protective layer 4, serving as the main channel for light propagation within the light guide device. The grating layer 2 is disposed on the waveguide layer 3, where the coupling grating 21 is responsible for coupling external light into the waveguide layer 3. As the core carrier for light propagation, the waveguide layer 3 efficiently receives light from the coupling grating 21 and, through the modulation effect of the output grating 22, transmits the light to the human eye O1, achieving a clear visual display effect. This design optimizes the light transmission path and improves the overall performance and reliability of the light guide device.

[0075] The light guide device provided in this embodiment includes a protective layer 4, see [link]. Figure 2 and Figure 7 The protective layer 4 is located on the optomechanical side of the waveguide layer 3 (the side where the optomechanical A is located, which is on the same side as the human eye 01). Its main function is to isolate the external optomechanical A from the waveguide layer 3, protecting the waveguide layer 3 from damage by the external environment. Compared to traditional resin waveguide architectures, the protective layer 4 in this application is optimized in design. Its primary function is to protect the waveguide layer 3, without needing to fully cover and protect the grating layer 2. This targeted design adjustment allows for a further reduction in the thickness of the protective layer 4, not only lowering material costs but also significantly reducing the overall weight of the light guide device, providing strong support for lightweight and portable product design.

[0076] Optionally, the protective layer 4 is made of resin material, that is, the protective layer 4 of the light guide device provided in the embodiments of this application is a resin protective layer, which is beneficial to achieving the lightweight of the light guide device.

[0077] When both the protective layer 4 and the waveguide layer 3 are made of resin material, the light guide device provided in this embodiment is a resin waveguide device. Its performance is superior to that of traditional resin waveguide architectures.

[0078] Of course, the material of the protective layer 4 in the light guide device provided in this application embodiment includes, but is not limited to, resin material.

[0079] The light guide device provided in this application introduces a low-refractive-index optical filling layer 5 between the grating layer 2 and the photochromic layer 1. The refractive index of this filling layer is lower than that of the grating layer 2, with the difference controlled between 0.2 and 0.5. This effectively reduces rainbow patterns, improves the invisibility of the grating, and significantly improves color uniformity, thus comprehensively enhancing the optical performance of the light guide device. Simultaneously, the optical filling layer 5 covers the coupling grating 22, providing an additional protective layer for the coupling grating 22 in the grating layer 2, enhancing the grating's abrasion resistance and reducing the risk of damage to the grating layer due to wiping. In terms of structural layout, the light guide device of this application sequentially stacks the photochromic layer 1, grating layer 2, waveguide layer 3, and protective layer 4 from the world side to the human eye side. This compact stacked structure helps to achieve a lighter AR optical display device. Specifically, the protective layer 4 is located on the optomechanical side of the waveguide layer 3. Its main function is to isolate the external optomechanical system A from the waveguide layer 3, rather than to fully protect the grating layer 2. This reduces the requirements for the surface accuracy of the protective layer 4 (e.g., a resin protective layer). This design allows for a further reduction in the thickness of the protective layer 4, simplifies the manufacturing process, and significantly reduces the overall weight of the light guide device. This provides strong support for the design of lighter and more portable AR optical display devices, while also improving the user experience.

[0080] In some examples of this application, the grating layer 2 further includes a transition grating 23, which is located on the same side of the waveguide layer 3 as the coupling grating 22, and the optical filling layer 5 also covers the transition grating 23.

[0081] The grating layer 2 may further include a deflection grating 23. The deflection grating 23 is used to change the propagation direction of light within the waveguide layer 3 to achieve a more flexible optical path design.

[0082] In this application, the angular grating 23 can be selectively configured as needed.

[0083] In other words, the light guide device provided in this application embodiment may only have an input grating 21 and an output grating 22, or it may have an input grating 21, an output grating 22 and a turning grating 23 simultaneously.

[0084] When the grating layer 2 includes a transition grating 23, the transition grating 23 can be located on the same side of the waveguide layer 3 as the coupling grating 22, so that the optical filling layer 5 can cover the transition grating 23 while covering the coupling grating 22.

[0085] In some examples of this application, the refractive index of the grating layer 2 is... n 2 and the refractive index of the waveguide layer 3 n 3. Satisfy: | n 2-n 3|≤0.5.

[0086] In the example provided in this application, key optical design parameters for the grating layer 2 and the waveguide layer 3 are given, namely, the absolute value of the difference in their refractive indices must be less than or equal to 0.5. This optical parameter plays a crucial role in optimizing the overall performance of the light guide device, as specifically shown below.

[0087] The optical design parameters in this example can improve the color uniformity of the displayed image. Specifically, when the refractive index difference between the grating layer 2 and the waveguide layer 3 is small (specifically less than or equal to 0.5), the reflection and refraction of light at the interface between the two are significantly reduced. This reduction in interface effect effectively decreases color distortion and unevenness caused by multiple reflections and refractions of light. As a result, light can maintain more consistent color characteristics when propagating within the waveguide layer 3, thereby significantly improving the overall color uniformity of the light guide device.

[0088] The optical design parameters in this example can appropriately enhance the invisibility of the grating. The invisibility of the grating is closely related to its scattering and diffraction effects on light. When the refractive index difference between the grating layer 2 and the waveguide layer 3 is less than or equal to 0.5, the scattering and diffraction effects of the grating on light are significantly reduced. This makes the grating more difficult to perceive by the human eye, thereby improving the visual effect of the light guide device and effectively reducing visual interference caused by the visibility of the grating.

[0089] The optical parameters in this example can also reduce the probability of rainbow effects. Rainbow effects are generally caused by multiple reflections and refractions of light within the waveguide layer, resulting in the spatial separation of light of different wavelengths. By controlling the refractive index difference between the grating layer 2 and the waveguide layer 3 to within 0.5, the number of reflections and refractions of light at their interface can be effectively reduced. This design adjustment significantly reduces the likelihood of rainbow effects, further improving the display quality of the light guide device.

[0090] Furthermore, considering the poor temperature resistance of the grating material, this application uses a low-refractive-index adhesive to cover at least a portion of the grating area via spin coating. When the refractive index difference between the grating layer 2 and the waveguide layer 3 is small, the requirement for the refractive index of the adhesive is relatively relaxed. However, it is still necessary to ensure that the refractive index of the adhesive is lower than that of the grating layer 2, and the difference between the two should preferably be maintained between 0.2 and 0.5. This design not only simplifies the manufacturing process and improves production efficiency, but also effectively reduces performance fluctuations caused by minor errors in the manufacturing process.

[0091] Optionally, the refractive index of the grating layer 2 n 2 and the refractive index of the waveguide layer 3 nThe differences between 3 are 0.05, 0.08, 0.1, 0.2, 0.3, 0.4, 0.5, etc.

[0092] In this application, a preferred optical parameter design is that the refractive index of the grating layer 2 is... n 2 and the refractive index of the waveguide layer 3 n 3. Satisfy: | n 2- n 3|≤0.1. Optimizing this parameter can achieve better optical display effects.

[0093] See some examples in this application. Figure 2 The coupling grating 21 adopts a reflective coupling structure, which is disposed on the world side surface of the waveguide layer 3 and located between the color-changing film layer 1 and the waveguide layer 3, and a reflective coating layer 6 is covered on the surface of the coupling grating 21.

[0094] See the example provided in this application. Figure 2 The coupling grating 21 employs a reflective coupling structure, which is disposed on the world-side surface of the waveguide layer 3 and located between the photochromic layer 1 and the waveguide layer 3. Furthermore, to enhance its reflective performance, a reflective coating layer 6 is applied to the surface of the coupling grating 21. The following is an optimized description of this design.

[0095] The reflective coupling structure design endows the coupling grating 21 with unique optical characteristics, enabling it to efficiently couple external light emitted from the external optomechanical A into the waveguide layer 3 for total internal reflection propagation through a highly efficient reflection mechanism. Compared to traditional transmissive or other coupling methods, this reflective design significantly improves the utilization rate of light energy because it can more effectively capture and guide light into the waveguide layer 3 for transmission, thereby greatly improving the coupling efficiency of light.

[0096] The introduction of the reflective coating layer 6 further modulates the optical performance of the coupling grating 21. By improving key optical parameters such as reflectivity and reducing scattering and absorption, the reflective coating layer 6 significantly optimizes the coupling characteristics of the coupling grating 21, allowing light to experience less energy loss before entering the waveguide layer 3, thereby further improving the overall coupling efficiency of the light. Therefore, this design not only enhances the transmission efficiency of light but also ensures the stability and consistency of light during transmission.

[0097] In the example provided in this application, a reflective coupling structure is combined with a reflective coating layer 6 to construct a highly efficient and stable light coupling system. This system can significantly improve the coupling efficiency of light from the external environment to the waveguide layer 3, thereby optimizing the overall brightness and clarity of the light guide device. The coverage of the reflective coating layer 6 not only enhances the optical performance of the coupling grating 21, but also reduces potential light loss and interference during transmission, bringing a more superior overall performance to the light guide device.

[0098] Furthermore, combined with the intelligent adjustment or filtering function of the color-changing film layer 1 for ambient light, and the meticulously optimized design of the coupling grating 21 and the reflective coating layer 6, the entire light guide device exhibits excellent environmental adaptability. Whether under strong direct light or in low light conditions, this light guide device provides stable and clear visual effects, fully meeting the diverse usage needs of users in different scenarios.

[0099] See some examples in this application. Figures 2 to 4 The height of the optical filling layer 5 is lower than the grating height of the coupling grating 21.

[0100] The optical filling layer 5 covers the grating layer 2, creating a protective barrier for the coupling grating 22 and / or the transition grating 23 regions. This design enhances the abrasion resistance of these critical areas, ensuring that the grating structure is protected from substantial damage during routine use or cleaning and maintenance, even if subjected to minor wiping or touching, thereby effectively extending the overall lifespan of the light guide device.

[0101] Furthermore, to ensure efficient and lossless coupling of light into the waveguide layer 3 at the coupling grating 21, the height of the optical filling layer 5 in this example is controlled to be lower than the height of the coupling grating 21. This design avoids potential interference of the optical filling layer 5 with the light coupling process, ensuring smooth and efficient light transmission.

[0102] However, when addressing the needs of specific application scenarios, if more comprehensive protection is required for the coupling grating 21, the optical filling layer 5 can be flexibly extended to cover this area, as detailed in [reference needed]. Figure 5 This design flexibility allows the protection range of the optical filling layer 5 to be customized according to actual needs, meeting diverse application scenarios.

[0103] exist Figure 3 and Figure 4In the structure shown, the height of the optical filling layer 5 is lower than that of the reflective coating layer 6 on the coupling grating 21. This design aims to ensure that the optical performance of the coupling grating 21 is not affected in any way, while providing it with the necessary protection, thus ensuring the overall performance and stability of the light guide device.

[0104] In this application, the optical filling layer 5 is coated using low-temperature processing methods such as spin coating or inkjet printing. These methods are not only simple to operate and easy to control, but also help to simplify the manufacturing process and improve production efficiency, laying the foundation for the large-scale production and widespread application of light guide devices.

[0105] See some examples in this application. Figures 3 to 5 The reflective coating layer 6 is a single-layer metal film, a combination of multiple dielectric films and metal films, or a multiple dielectric film.

[0106] Single-layer metal film: This film, through its high reflectivity, effectively reduces light transmission in the coupling grating 21 region, ensuring that more light can be successfully coupled into the waveguide layer 3. Its advantages lie in its simple structure, convenient fabrication, and relatively low cost, providing an economical and efficient reflection solution for light guide devices.

[0107] Combinations of multilayer dielectric and metallic films: This combination creates more complex and sophisticated optical structures. By adjusting the thickness and refractive index of each layer, precise control over specific wavelengths of light can be achieved, including but not limited to increasing reflectivity and reducing scattering and absorption. Compared to single-layer metallic films, this combination offers greater freedom in optical control, allowing designs to be customized for different application needs, thereby achieving superior optical performance.

[0108] Multilayer dielectric film: By precisely controlling the refractive index and thickness of each layer, a multilayer dielectric film can form a thin film structure with specific optical properties. In the region of the coupling grating 21, this film design can effectively optimize the coupling efficiency of light while reducing scattering and absorption, providing clear and uniform light output for the light guide device.

[0109] The reflective coating layer 6 in this application example is designed to enhance the reflectivity of light in the region of the coupling grating 21 while reducing transmission and scattering phenomena. This ensures that more light can be efficiently coupled into the waveguide layer 3, improving the overall brightness of the light guide device. By flexibly adjusting the structure and material of the reflective coating layer 6, the design can achieve precise control of specific wavelengths of light, further reducing scattering and absorption, and improving the color uniformity and clarity of the light guide device. Furthermore, both the metal film and the multilayer dielectric film exhibit good stability and durability, ensuring that the reflective coating layer 6 maintains stable optical performance during long-term use, thereby improving the reliability and lifespan of the light guide device.

[0110] See some examples in this application. Figure 7 The coupling grating 21 is a transmission coupling structure, which is disposed on the human eye side surface of the waveguide layer 3. It and the output grating 22 are respectively located on two opposite surfaces of the waveguide layer 3, and are used to directly transmit and couple the emitted light of the optomechanism A into the waveguide layer 3. The optomechanism A and the human eye O1 are located on the same side of the waveguide layer 3.

[0111] See the example provided in this application. Figure 7 The coupling grating 21 adopts a transmissive coupling structure design and is disposed on the eye-side surface of the waveguide layer 3. This structure is characterized in that it and the output grating 22 are located on opposite surfaces of the waveguide layer 3. Specifically, this transmissive coupling structure design can directly transmit and couple the emitted light from the optomechanism A into the waveguide layer 3, and the optomechanism A and the eye 01 are located on the same side of the waveguide layer 3. This layout greatly optimizes the light transmission efficiency.

[0112] The explanation of this example is as follows: The design feature of the transmissive coupling structure is that it can directly and efficiently transmit the light emitted by the optomechanical A into the waveguide layer 3 using the coupling grating 21, effectively reducing light loss at the coupling interface and thus significantly improving the coupling efficiency. This efficient coupling mechanism plays a decisive role in improving the overall brightness and clarity of the light guide device because it ensures that more light can enter the waveguide layer 3 and be transmitted without loss.

[0113] Crucially, the example presented in this application innovatively eliminates the coating process for the coupling grating 21 found in traditional architectures. This adjustment effectively avoids the risk of waveguide layer 3 deformation that may be caused by the poor temperature resistance of the resin waveguide material.

[0114] Although previous low-temperature coating techniques have reduced the thermal impact on resin waveguides to some extent, the extreme thermal sensitivity of resin materials means that even low-temperature coating operations still pose a potential risk of inducing waveguide deformation. Therefore, this application omits the coating step of the coupling grating 21, significantly simplifying the manufacturing process, reducing production costs, and substantially improving product yield and long-term reliability. This innovative architecture opens new avenues for the application of resin waveguides in precision optics fields such as AR, providing a more stable, efficient, and economical optical solution.

[0115] See some examples in this application. Figure 2 and Figure 7The color-changing film layer 1 has a curved surface structure, and its curved surface structure is adapted to the contour of the grating layer 2 to provide curved surface support for the grating layer 2; wherein, the edge region of the color-changing film layer 1 is fixedly connected to the edge region of the waveguide layer 3 to form a closed optical cavity structure.

[0116] Combination Figure 2 and Figure 7 The photochromic layer 1 is designed with a curved surface structure, which is adapted to the contour of the grating layer 2, thereby providing a stable and fitting curved surface support for the grating layer 2. Furthermore, the edge region of the photochromic layer 1 and the edge region of the waveguide layer 3 are fixedly connected by an optical filling layer 5 or other adhesive layers, together forming a closed and stable optical cavity structure.

[0117] The following is a more in-depth explanation of this example:

[0118] First, the curved structure design of the color-changing film layer 1 not only provides a solid curved support foundation for the grating layer 2, but this support also plays a crucial role in reducing deformation and potential damage to the grating layer 2 during long-term use. As a key component for light coupling and transmission, the reduction of deformation of the grating layer 2 directly affects the optical performance stability and lifespan of the light guide device.

[0119] Secondly, the edge region of the photochromic layer 1 can be fixedly connected to the edge region of the waveguide layer 3 through the optical filling layer 5. This design significantly enhances the overall strength of the entire waveguide structure. The optical filling layer 5 not only has excellent bonding performance, but also effectively disperses and mitigates the impact of external stress on the waveguide structure, thereby greatly reducing the risk of structural damage caused by external forces and improving the durability and long-term reliability of the waveguide structure.

[0120] Furthermore, the curved surface structure of the color-changing sheet layer 1 designed in this application provides a new approach to solving a series of problems in the prior art. In conventional technologies, controlling the air gap between the protective layer 4 and the waveguide layer 3 often faces many challenges, and the surface quality of the protective layer 4 is also difficult to fully guarantee. The color-changing sheet layer 1 design of this application can overcome these problems.

[0121] Specifically, the curved color-changing sheet layer 1 not only possesses excellent color-changing capabilities, automatically adjusting its transmittance according to ambient light or user needs, providing a more comfortable and intelligent user experience for light guide devices, but more importantly, it also provides stable curved support for the grating layer 2, helping to maintain the flatness and long-term stability of the grating layer 2 and reducing the risk of deformation caused by external forces or internal stress.

[0122] In existing technologies, a relatively thick protective layer is typically required to ensure that the protective layer 4 does not come into contact with the grating layer 2 due to surface deformation. However, this not only increases material costs and manufacturing difficulty but may also adversely affect the optical performance of the light guide device. In this application, since the curved structure of the photochromic layer 1 provides a stable support, the thickness requirement for the protective layer 4 can be significantly reduced. This means that a thinner protective layer 4 can be used to achieve the same protective effect while maintaining the stability of the waveguide structure and excellent optical performance.

[0123] Furthermore, the introduction of the curved photochromic layer 1 also positively impacts the air gap between the protective layer 4 and the waveguide layer 3. Since the curved photochromic layer 1 provides a stable supporting foundation, reducing the risk of deformation of the protective layer 4, the size and distribution of the air gap can be controlled more precisely. This precise control helps optimize the optical performance of the light guide device, reduce scattering and absorption losses, and improve light transmission efficiency and clarity.

[0124] It is worth mentioning that the curved surface structure design of the color-changing film layer 1 also has a certain degree of scalability. It can be customized according to the needs of different light guide devices, such as adjusting parameters like the surface curvature, to meet diverse application scenarios and user requirements. This flexibility and customizability give the color-changing film layer 1 broad application prospects and development potential in the field of light guide devices.

[0125] In some examples of this application, the color-changing sheet layer 1 includes: a substrate layer made of electrochromic material or photochromic material; or, a resin or glass substrate with a photosensitive material layer coated on its surface.

[0126] In the example provided in this application, the color-changing film layer 1 has diverse material compositions, specifically covering the following two main types:

[0127] Firstly, a matrix layer composed directly of electrochromic or photochromic materials is used. These materials possess unique color-changing properties and can undergo changes in optical properties under specific external stimuli.

[0128] Secondly, resin or glass is used as the substrate, and a layer of photosensitive material is coated on its surface. This composite structure combines the stability of the substrate material with the color-changing function of the photosensitive material, providing more design possibilities for the color-changing film layer 1.

[0129] Electrochromic materials, as a type of smart material, are characterized by their ability to precisely and reversibly change their optical properties under the influence of external stimuli such as an electric field, encompassing multiple key optical parameters including transmittance, reflectance, and color. In this example, when the electrochromic material is selected as the main component of the color-changing layer 1, it endows the light guide device with light-modulating capabilities. By controlling the intensity and direction of the electric field applied to the electrochromic material, users can dynamically adjust the light transmittance of the color-changing layer 1 in real time, thereby achieving control over the transmission or reflection of light. This controllability not only helps optimize the display effect of the light guide device under different ambient light conditions but also effectively improves the user's visual comfort and user experience.

[0130] In addition to electrochromic materials, this application also considers the application of other transparent or translucent materials with color-changing functions, such as photochromic materials. Photochromic materials can undergo a reversible color-changing reaction under illumination of specific wavelengths of light. These materials each have their own characteristics, providing a rich selection and flexibility for the design of the color-changing layer 1. The most suitable color-changing material can be flexibly selected according to specific application scenarios and needs to achieve the best light adjustment effect.

[0131] It is worth mentioning that, in another example of this application, the photochromic layer 1 adopts a composite structure combining a resin or glass substrate with a photosensitive material layer. Resin substrates are favored for their lightweight, ease of processing, and low cost, while glass substrates are known for their high light transmittance, high hardness, and excellent chemical stability. By coating a photosensitive material layer on the substrate surface, the photochromic layer 1 not only retains the original advantages of the substrate material but also gains the ability to dynamically respond to light. When external lighting conditions change, the photosensitive material layer can quickly sense and react, adjusting the overall light transmittance of the photochromic layer 1 by changing its own optical properties.

[0132] In this application, the core function of the color-changing layer 1 is to provide dynamic adjustment capability for light. This function enables the light guide device to adjust its optical performance in real time according to the actual ambient light conditions or the specific usage needs of the user, thereby achieving a more comfortable and efficient display effect.

[0133] For example, in strong light environments, the color-changing film layer 1 can reduce light transmittance, minimizing interference from external light on the display effect of the light guide device; while in low light environments, it can increase light transmittance, improving the brightness and clarity of the display. This dynamic adjustment capability not only improves the adaptability and practicality of the light guide device but also brings users a higher quality and more personalized visual experience.

[0134] See some examples in this application. Figure 6 and Figure 10 The optical filling layer 5 is formed on the surface of the waveguide layer 3 near the photochromic layer 1 by spin coating.

[0135] See the example provided in this application. Figure 6 and Figure 10 The optical filler layer 5 is uniformly formed on the surface of the waveguide layer 3 near the photochromic layer 1 via a spin-coating process. The optical filler layer 5 is, for example, a low-refractive-index adhesive. Specifically, this spin-coating process controls the rotation speed and adhesive supply to ensure the adhesive is distributed uniformly and controllably on the surface of the waveguide layer 3, thereby forming a thin film with precise thickness and good uniformity. This process not only ensures the uniformity and consistency of the optical filler layer 5 but also lays the foundation for subsequent optical performance optimization.

[0136] Unlike traditional design concepts that require an absolutely smooth surface for the optical filler layer, this application proposes a novel design approach that allows specific protrusion structures 51 to exist on the surface of the optical filler layer 5. These protrusion structures 51 mainly originate from the natural flow and curing characteristics of the adhesive during spin coating, or they may be intentionally introduced through specially designed process steps. Regardless of their origin, these protrusion structures 51 play an important role in optimizing optical performance.

[0137] Specifically, the protrusions 51 on the surface of the optical filling layer 5 significantly increase the scattering effect of light on its surface. When light is incident on these protrusions, it undergoes multi-directional scattering, thereby distributing the light more evenly across the various parts of the waveguide layer 3. This uniform scattering helps improve the coupling efficiency of light, meaning more light can be effectively guided into the waveguide layer 3 and propagated along a predetermined path; at the same time, it can also significantly improve the uniformity of light, avoiding the problem of excessively strong or weak light in local areas, thus comprehensively improving the overall optical performance.

[0138] Furthermore, the design concept of allowing the presence of protrusion structures 51 on the surface of the optical filling layer 5 also brings significant advantages in manufacturing processes. In traditional processes, obtaining a smooth optical filling layer surface often requires additional smoothing or polishing steps, which not only increases manufacturing costs but also extends the production cycle. The design in this application avoids this process, simplifying the manufacturing process, reducing manufacturing costs and time, and improving production efficiency by accepting and utilizing the presence of the protrusion structures 51.

[0139] In some examples of this application, the thickness T of the protective layer 4 is 0.05mm ≤ T ≤ 0.5mm.

[0140] In the example provided in this application, the thickness T of the protective layer 4 is specified to be in the range of 0.05 mm to 0.5 mm. This thickness range is designed based on a comprehensive consideration of the overall performance, durability, and lightweight requirements of the light guide device.

[0141] Thinner protective layers (close to 0.05mm, such as 0.05mm~0.1mm) help achieve the goal of lightweight light guide devices, reduce overall weight, and improve wearing comfort, especially suitable for portable devices such as AR glasses.

[0142] A thicker protective layer (close to 0.5mm, such as 0.45mm~0.5mm) further enhances the durability of the light guide device, better resisting potential damage such as scratches and impacts during daily use, and extending the product's lifespan.

[0143] Therefore, the thickness range design in this application example satisfies the dual requirements of light guide devices for lightweight and durability, while also ensuring the feasibility of the manufacturing process and the stability of product performance.

[0144] Optionally, the thickness T of the protective layer 4 can be 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, or 0.5mm.

[0145] It is worth mentioning that the protective layer 4 is located on the optomechanical side of the waveguide layer 3, and its function has changed. It primarily serves to isolate the external optomechanical system A from the waveguide layer 3, rather than acting as a traditional protective grating layer. This change in functional focus reduces the requirements for the surface precision of the protective layer 4. Consequently, the thickness of the protective layer 4 can be further reduced, simplifying the manufacturing process, lowering production costs, and reducing the overall weight of the light guide device. This design provides strong support for the design of lighter and more portable AR devices, greatly improving user comfort and convenience when using AR optical display devices.

[0146] See some examples in this application. Figure 3 and Figure 4 ,as well as Figure 8 and Figure 9 The coupled grating 21 can be a tilted grating, a blazed grating, or a straight-tooth grating.

[0147] According to another embodiment of this application, an optical display device is provided, see [link to relevant documentation]. Figure 2 and Figure 7 The optical display device includes an optical engine A and a light guide device as described above.

[0148] The optical display devices provided in the embodiments of this application are, for example, near-eye optical display devices, such as AR smart glasses or AR smart helmets.

[0149] The specific implementation of the optical display device in this application can refer to the various embodiments of the light guide device described above. Therefore, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0150] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0151] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A light guide device, characterized in that, From the world side to the human eye side, it includes a layered photochromic film layer (1), a grating layer (2), a waveguide layer (3), and a protective layer (4). The grating layer (2) includes an input grating (21) and an output grating (22), wherein the output grating (22) is disposed on the world side surface of the waveguide layer (3) and located between the waveguide layer (3) and the color-changing film layer (1); An optical filling layer (5) is formed between the grating layer (2) and the photochromic layer (1), and the optical filling layer (5) at least covers the coupling grating (22), and the refractive index of the optical filling layer (5) is... n 1 is lower than the refractive index of the grating layer (2). n 2, and 0.2≤ n 2- n 1≤0.5; The protective layer (4) is located on the optomechanical side of the waveguide layer (3) and is used to isolate the external optomechanical system (A) from the waveguide layer (3). The refractive index of the grating layer (2) n 2 and the refractive index of the waveguide layer (3) n 3. Satisfy: | n 2- n 3|≤0.1; The grating layer (2) also includes a transition grating (23), which is located on the same side of the waveguide layer (3) as the coupling grating (22), and the optical filling layer (5) also covers the transition grating (23). The color-changing film layer (1) has a curved structure, and its curved structure is adapted to the contour of the grating layer (2) to provide curved support for the grating layer (2); The thickness T of the protective layer (4) is 0.05mm≤T≤0.5mm.

2. The light guide device according to claim 1, characterized in that, The coupling grating (21) adopts a reflective coupling structure, which is disposed on the world side surface of the waveguide layer (3) and located between the color-changing film layer (1) and the waveguide layer (3), and a reflective coating layer (6) is covered on the surface of the coupling grating (21).

3. The light guide device according to claim 2, characterized in that, The height of the optical filling layer (5) is lower than the grating height of the coupled grating (21).

4. The light guide device according to claim 2, characterized in that, The reflective coating layer (6) is a single-layer metal film, a combination of a multilayer dielectric film and a metal film, or a multilayer dielectric film.

5. The light guide device according to claim 1, characterized in that, The coupling grating (21) is a transmission coupling structure and is disposed on the human eye side surface of the waveguide layer (3). It and the output grating (22) are respectively located on two opposite surfaces of the waveguide layer (3) and are used to directly transmit and couple the outgoing light of the optomechanism (A) into the waveguide layer (3). The optomechanism (A) and the human eye (01) are located on the same side of the waveguide layer (3).

6. The light guide device according to claim 1, characterized in that, The edge region of the color-changing film layer (1) is fixedly connected to the edge region of the waveguide layer (3) to form a closed optical cavity structure.

7. The light guide device according to claim 1, characterized in that, The color-changing film layer (1) includes: A substrate layer composed of electrochromic or photochromic materials; or, A resin or glass substrate, the surface of which is coated with a photosensitive material layer.

8. The light guide device according to claim 1, characterized in that, The optical filling layer (5) is formed on the surface of the waveguide layer (3) near the color-changing film layer (1) by spin coating.

9. An optical display device, characterized in that, include: Optical mechanism (A); and The light guide device as described in any one of claims 1-8; The optical engine (A) is located on one side of the protective layer (4) of the light guide device.

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