Light guide device display apparatus and method of manufacturing the same, head-mounted display apparatus

Abstract

The embodiment of the present application provides a light guide device display device and a preparation method thereof, and a head-mounted display device; the light guide device display device comprises a light machine, a diffraction waveguide layer, a sealing layer, a reflective film and a total reflection maintaining layer; the diffraction waveguide layer is used for transmitting input light; the sealing layer is used for sealingly connecting the light machine and the diffraction waveguide layer; the reflective film is arranged between the sealing layer and the diffraction waveguide layer; the total reflection maintaining layer is arranged between the diffraction waveguide layer and the reflective film, and at least partially covers a total reflection propagation area of the diffraction waveguide layer; wherein the refractive index n0 of the total reflection maintaining layer is lower than the refractive index n1 of the sealing layer, the total reflection maintaining layer is configured to reconstruct, in the presence of the sealing layer, the optical condition of the total reflection critical angle θ c of the diffraction waveguide layer, and the total reflection maintaining layer comprises: a first interface combined with the diffraction waveguide layer, used for establishing the optical condition of the total reflection critical angle θ c ; and a second interface combined with the reflective film, used for controlling the reflection of light of a specific angle.

Description

Technical Field

[0001] This application relates to the field of optical display technology, and more specifically, to a light guide device display device and its preparation method, and a head-mounted display device. Background Technology

[0002] With the development of optical display technologies such as augmented reality (AR), the design of optical systems for head-mounted displays faces severe technical challenges. As a core component of the optical system, the performance of the light guide directly determines the imaging quality and user experience of the head-mounted display. However, existing coupling structures between the optomechanical system and the light guide suffer from significant optical efficiency losses. This is mainly due to the fact that, to ensure dust and moisture resistance, a sealing layer is required between the optomechanical system and the light guide in current technologies. However, the refractive index of the sealing material is approximately 1.4-1.5, higher than that of air. This increases the critical angle for total internal reflection at the interface between the light guide and the sealing layer. Light that would otherwise be totally internally reflected at the air interface will refract and leak due to the new critical angle. According to measured data, the optical efficiency loss of such structures can reach 30-40%, or even higher.

[0003] Among existing solutions to address light loss during light propagation in light guide devices, the direct compensation scheme using a reflective film is a novel design. This scheme is disclosed in patent application WO2025025623A1, entitled "Optical Display Module and Head-Mounted Device." Its core principle is to add a reflective film between the waveguide and the sealing layer. The aim is to reflect light lost due to improper sealing structure design (such as using high-refractive-index sealant to increase the critical angle of total internal reflection, causing some light to penetrate the light guide device), thus reducing light loss. However, this scheme has significant limitations: firstly, the reflective film's broad-band reflectivity is insufficient, failing to efficiently reflect all wavelengths of light, resulting in some wavelengths still being lost in application; secondly, the reflection process itself involves losses, reducing optical efficiency with each reflection. Essentially, this scheme does not address the core issue of the disruption of the total internal reflection condition. The critical angle of total internal reflection at the interface between the sealing layer and the light guide device remains variable, allowing light to easily penetrate the light guide device, and the reflective film cannot prevent light loss at its source. Therefore, although it alleviates the light loss problem to some extent, the loss in optical efficiency is still significant.

[0004] In addition, another existing technology addresses the light loss problem during light propagation in light guide devices. Referring to patent application number 202111034187.3, entitled "Display Module and Head-Mounted Device," this invention discloses a rigid seal between the optical waveguide and the host device. The side of the rigid seal closest to the optical waveguide is configured with a rough surface, creating a gap between the optical waveguide and the rigid seal. It can be seen that this solution still leaves a certain air gap between the optical waveguide and the host device, preventing a complete seal between them. Summary of the Invention

[0005] The purpose of this application is to provide a new technology solution for a light guide device display device and its preparation method, as well as a head-mounted display device.

[0006] In a first aspect, embodiments of this application provide a light guide device display device, the light guide device display device comprising:

[0007] An optical engine is used to provide incident light rays;

[0008] A diffraction waveguide layer for transmitting the incident light beam includes an input grating and an output grating. The input grating is disposed in a first region of the diffraction waveguide layer and configured to couple the incident light beam emitted by the optomechanism into the diffraction waveguide layer. The output grating is disposed in a second region of the diffraction waveguide layer and configured to couple the light beam propagating by total internal reflection within the diffraction waveguide layer outward.

[0009] A sealing layer is used to seal the connection between the optomechanical system and the diffraction waveguide layer.

[0010] A reflective film is disposed between the sealing layer and the diffraction waveguide layer;

[0011] A total reflection maintenance layer is disposed between the diffraction waveguide layer and the reflective film, and at least partially covers the total reflection propagation region of the diffraction waveguide layer;

[0012] The refractive index n0 of the total reflection maintaining layer is lower than the refractive index n1 of the sealing layer. The total reflection maintaining layer is configured to reconstruct the diffraction waveguide layer to satisfy the critical angle θ of total reflection in the presence of the sealing layer. c The optical conditions, and the total internal reflection maintaining layer comprises:

[0013] The first interface, which is combined with the diffraction waveguide layer, is used to establish the critical angle θ for total internal reflection. c Optical conditions; and

[0014] The second interface, combined with the reflective film, is used to control the reflection of light at a specific angle.

[0015] Optionally, when the incident light propagates in the diffraction waveguide layer:

[0016] For incident angle θ≥θ c The incident light rays are capable of total internal reflection at the first interface, with a FOV of ≥70%;

[0017] For the incident angle θ < θ c The incident light rays can penetrate the total reflection maintenance layer and be reflected back to the diffraction waveguide layer by the reflective film;

[0018] Where, θ c =arcsin(n0 / n2), where n2 is the refractive index of the diffraction waveguide layer, and n2 and n0 satisfy: n2-n0≥0.4.

[0019] Optionally, on the vertical projection plane of the total internal reflection propagation path of the diffraction waveguide layer, the projection of the reflective film falls completely within the projection range of the total internal reflection maintenance layer.

[0020] Optionally, the total reflection maintaining layer includes a low-refractive-index material layer, the refractive index of which is n0, and n0 is less than 1.3.

[0021] Optionally, the total reflection maintenance layer further includes:

[0022] A transparent connecting layer is disposed between the diffraction waveguide layer and the low-refractive-index material layer, and its refractive index is between that of the diffraction waveguide layer and the low-refractive-index material layer; and / or,

[0023] A transparent protective layer is disposed between the low-reflection material layer and the reflective film.

[0024] Optionally, the thickness of the total reflection maintenance layer is 1 μm to 100 μm.

[0025] Optionally, the reflective film is a single-layer metal film, a multilayer dielectric film, or a metal-dielectric composite film;

[0026] The reflective film has a reflectivity of ≥90% in the visible light band.

[0027] Optionally, the sealing layer is an optically transparent adhesive, and the sealing layer is disposed around the gap between the optomechanical system and the diffraction waveguide layer.

[0028] Optionally, the diffraction waveguide layer includes:

[0029] A coupling grating is disposed in the first region of the diffraction waveguide layer and configured to couple the incident light emitted by the optomechanical system into the diffraction waveguide layer.

[0030] A coupling grating is disposed in the second region of the diffraction waveguide layer and configured to couple out light rays propagating by total internal reflection within the diffraction waveguide layer;

[0031] The total internal reflection sustaining layer covers at least the light propagation path connecting the first region and the second region, and on the periphery of the coupling grating, the total internal reflection sustaining layer forms a total internal reflection sustaining region that at least partially surrounds the coupling grating.

[0032] Optionally, the diffraction waveguide layer further includes a folding grating located on the light propagation path between the input grating and the output grating.

[0033] Optionally, the light guide device display device further includes a protective layer, which is disposed on the side of the diffraction waveguide layer where the coupling grating and the coupling out grating are provided, and an air gap is formed between the protective layer and the diffraction waveguide layer.

[0034] Secondly, embodiments of this application provide a head-mounted display device, the head-mounted display device comprising:

[0035] The outer casing; and

[0036] The light guide device display device as described in the first aspect.

[0037] Thirdly, embodiments of this application provide a method for fabricating a light guide device display device, the method comprising:

[0038] A total reflection sustaining layer is formed on the diffraction waveguide layer, and the total reflection sustaining layer at least partially covers the total reflection propagation region of the diffraction waveguide layer;

[0039] A reflective film is formed on the total reflection maintenance layer, such that the total reflection maintenance layer is also located between the diffraction waveguide layer and the reflective film;

[0040] A sealing layer is formed on the reflective film, and the optomechanic is connected to the sealing layer to seal the connection between the optomechanic and the diffraction waveguide layer.

[0041] Wherein, the refractive index n0 of the total internal reflection maintaining layer is lower than the refractive index n1 of the sealing layer, and in the presence of the sealing layer, the total internal reflection maintaining layer reconstructs the diffraction waveguide layer to satisfy the critical angle θ of total internal reflection. c The optical conditions, and the total internal reflection sustaining layer includes: a first interface combined with the diffraction waveguide layer, for establishing the total internal reflection critical angle θ. c The optical conditions; and the second interface combined with the reflective film, for controlling the reflection of light at a specific angle.

[0042] Fourthly, embodiments of this application provide a sealing structure for a light guide device display device, the sealing structure comprising:

[0043] A total reflection sustaining layer is disposed on the diffraction waveguide layer and at least covers the total reflection propagation region of the diffraction waveguide layer;

[0044] A reflective film is disposed on the total reflection maintenance layer, such that the total reflection maintenance layer is also located between the diffraction waveguide layer and the reflective film;

[0045] A sealing layer is disposed on the reflective film and connected to the optomechanical system. The sealing layer is used to seal the connection between the optomechanical system and the diffraction waveguide layer.

[0046] Wherein, the refractive index n0 of the total internal reflection maintaining layer is lower than the refractive index n1 of the sealing layer, and in the presence of the sealing layer, the total internal reflection maintaining layer reconstructs the diffraction waveguide layer to satisfy the critical angle θ of total internal reflection. c The optical conditions, and the total internal reflection sustaining layer includes: a first interface combined with the diffraction waveguide layer, for establishing the total internal reflection critical angle θ. c The optical conditions; and the second interface combined with the reflective film, for controlling the reflection of light at a specific angle.

[0047] Optionally, the total reflection maintaining layer includes a low-refractive-index material layer, wherein the refractive index of the low-refractive-index material layer is less than 1.3, and the thickness of the total reflection maintaining layer is 1 μm to 100 μm.

[0048] The beneficial effects of this application are as follows:

[0049] The light guide device display device provided in this application embodiment introduces a total internal reflection maintenance layer between the diffraction waveguide layer and the reflective film. The refractive index n0 of the total internal reflection maintenance layer is lower than the refractive index n1 of the sealing layer. It is configured to reconstruct the diffraction waveguide layer 2 to satisfy the critical angle θ of total internal reflection in the presence of the sealing layer 3. c This design addresses the problem of total internal reflection being compromised by the presence of a sealing layer, significantly reducing refraction and leakage due to failure to meet total internal reflection conditions, and thus substantially improving optical efficiency. In this application, the total internal reflection maintenance layer and the reflective film work synergistically. The maintenance layer ensures that most light undergoes total internal reflection at its interface with the diffraction waveguide layer, reducing light penetration into the reflective film. For the few rays that penetrate the maintenance layer, the reflective film reflects them back to the diffraction waveguide layer. Since the maintenance layer significantly reduces the amount of light that needs to be reflected by the reflective film, it compensates to some extent for the insufficient broadband reflectivity of the reflective film, improving the overall structure's ability to reflect light of different wavelengths and further enhancing optical efficiency.

[0050] Because the light guide device of this application can effectively solve the problem of total internal reflection being disrupted, reduce optical efficiency loss, and minimize reflection loss, more light can be efficiently transmitted to the user's eyes. This will significantly improve the imaging quality of the head-mounted display device, making the image clearer and brighter. At the same time, the good imaging quality can bring users a more comfortable and realistic visual experience, meeting users' needs for high-quality head-mounted display devices.

[0051] 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

[0052] 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.

[0053] Figure 1 This is one of the structural schematic diagrams of the light guide device display device provided in the embodiments of this application;

[0054] Figure 2 This is a schematic diagram of the optical path of a light guide device display device provided in an embodiment of this application;

[0055] Figure 3 This is one of the top views of the light guide device display device provided in the embodiments of this application;

[0056] Figure 4 This is a second top view of the light guide device display device provided in the embodiments of this application;

[0057] Figure 5 This is the third top view of the light guide device display device provided in the embodiments of this application;

[0058] Figure 6 This is a second schematic diagram of the structure of the light guide device display device provided in the embodiments of this application;

[0059] Figure 7 This is the third schematic diagram of the structure of the light guide device display device provided in the embodiments of this application;

[0060] Figure 8 This is the fourth schematic diagram of the structure of the light guide device display device provided in the embodiments of this application;

[0061] Figure 9 This is one of the structural schematic diagrams of the total internal reflection maintenance layer of the light guide device display device provided in the embodiments of this application;

[0062] Figure 10 This is a second schematic diagram of the total internal reflection maintenance layer of the light guide device display device provided in the embodiments of this application;

[0063] Figure 11 This is the third schematic diagram of the total internal reflection maintenance layer of the light guide device display device provided in the embodiments of this application;

[0064] Figure 12 This is one of the K-space diagrams of the light guide device display device provided in the embodiments of this application;

[0065] Figure 13 This is the second K-space diagram of the light guide device display device provided in the embodiments of this application.

[0066] Explanation of reference numerals in the attached figures:

[0067] 1. Optomechanical; 2. Diffraction waveguide layer; 201. Coupled-in grating; 202. Coupled-out grating; 203. Turning grating; 3. Sealing layer; 4. Reflective film; 5. Total internal reflection maintenance layer; 501. Low-refractive-index material layer; 502. Transparent connecting layer; 503. Transparent protective layer; 6. Protective layer. Detailed Implementation

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] The light guide device display device and its preparation method, as well as the head-mounted display device provided in the embodiments of this application, will be described in detail below with reference to the accompanying drawings.

[0074] According to one embodiment of this application, a light guide device display device is provided, see [link to relevant documentation]. Figure 1The light-guiding device display includes: an optomechanical system 1, a diffractive waveguide layer 2, a sealing layer 3, a reflective film 4, and a total internal reflection maintenance layer 5. The optomechanical system 1 provides incident light. The diffractive waveguide layer 2 transmits the incident light and includes a coupling grating 201 and a coupling grating 202. The coupling grating 201 is disposed in a first region of the diffractive waveguide layer 2 and configured to couple the incident light emitted by the optomechanical system 1 into the diffractive waveguide layer 2; the coupling grating 202 is disposed in a second region of the diffractive waveguide layer 2 and configured to couple the light propagating within the diffractive waveguide layer 2 under total internal reflection outwards. The sealing layer 3 seals the optomechanical system 1 to the diffractive waveguide layer 2. The reflective film 4 is disposed between the sealing layer 3 and the diffractive waveguide layer 2. The total internal reflection maintenance layer 5 is disposed between the diffractive waveguide layer 2 and the reflective film 4, and at least partially covers the total internal reflection propagation region of the diffractive waveguide layer 2. The total reflection maintaining layer 5 has a refractive index n0 lower than the refractive index n1 of the sealing layer 3. The total reflection maintaining layer 5 is configured to reconstruct the diffraction waveguide layer 2 to satisfy the critical angle θ of total reflection in the presence of the sealing layer 3. c The optical conditions. Furthermore, the total internal reflection sustaining layer 5 includes a first interface that integrates with the diffraction waveguide layer 2, the first interface being used to establish the critical angle θ for total internal reflection. c The optical conditions. The total internal reflection maintaining layer 5 also includes a second interface combined with the reflective film 4, the second interface being used to control the reflection of light at a specific angle.

[0075] The light guide device display device provided in this application has broad application potential in the field of near-eye optical displays. Specifically, the light guide device display device provided in this application can be adapted to near-eye optical display devices such as augmented reality (AR) and virtual reality (VR), bringing excellent optical performance and display effects to these advanced display technologies.

[0076] The light guide device display device provided in this application embodiment includes an optomechanical system 1. The optomechanical system 1 is the light source of the entire light guide device display device, responsible for emitting light (i.e., incident light) for imaging display. This light will be coupled into the diffraction waveguide layer 2, and after propagation through total internal reflection, it will finally be coupled out for the user to view.

[0077] The light guide device display device provided in this application embodiment includes a diffraction waveguide layer 2. The diffraction waveguide layer 2 is one of the core components of the light guide device display device, and it is responsible for propagating the incident light emitted by the optomechanism 1 through total internal reflection. Specifically, through the internally set coupling grating 201, coupling output grating 202 (and possibly turning grating 203), the light is effectively coupled into, propagated, and coupled out of the diffraction waveguide layer 2.

[0078] The total internal reflection propagation region of the diffraction waveguide layer 2 has a critical angle θ0 for total internal reflection, the magnitude of which depends on the refractive index n of air. 空气 And the refractive index n2 of the diffraction waveguide layer 2. Specifically, θ0 needs to satisfy θ0≥arcsin(n 空气 The condition is / n2). Only when the incident angle θ of the incident light is greater than or equal to this critical angle θ0 can the light achieve total internal reflection transmission within the diffraction waveguide layer 2.

[0079] The light guide device display device provided in this application embodiment includes a total internal reflection sustaining layer 5. The total internal reflection sustaining layer 5 is disposed between the diffraction waveguide layer 2 and the reflective film 4. A certain refractive index difference (e.g., n2-n0≥0.4) is required between the refractive index n0 of the total internal reflection sustaining layer 5 and the refractive index n2 of the diffraction waveguide layer 2, and the refractive index n0 of the total internal reflection sustaining layer 5 should be as low as possible compared to the refractive index n2 of the diffraction waveguide layer 2. This refractive index configuration plays a crucial role: it ensures that when incident light propagates in the diffraction waveguide layer 2, the condition of total internal reflection is met as much as possible, thereby effectively confining the incident light to propagate within the diffraction waveguide layer 2 without directly penetrating it. Simultaneously, due to the low refractive index n0 of the total internal reflection sustaining layer 5, incident light is less prone to reflection loss at the interface between the diffraction waveguide layer 2 and the total internal reflection sustaining layer 5. This helps improve light utilization efficiency, ensuring that more light can propagate along the expected path, thereby improving the overall light efficiency of the light guide device display device.

[0080] The light guide device display device provided in this application includes a reflective film 4. The reflective film 4 is disposed between the total reflection maintaining layer 5 and the sealing layer 3. The reflective film 4 provided in this application has extremely high reflectivity; for example, its reflectivity for visible light can be as high as 90%, or even increased to 96% or 98%, thereby forming a highly efficient high-reflectivity zone. See also... Figure 2 This design enables the reflective film 4 to effectively reflect light that has penetrated the total reflection maintenance layer 5 back into the diffraction waveguide layer 2, which greatly improves the utilization rate and propagation efficiency of light and further optimizes the overall optical performance of the light guide device.

[0081] The light guide device display device provided in this application embodiment includes a sealing layer 3. See also... Figure 1 The sealing layer 3 is mainly used to seal the connection between the optomechanical system 1 and the diffraction waveguide layer 2, preventing dust, moisture, and other impurities from entering the gap between the optomechanical system 1 and the diffraction waveguide layer 2. This sealing structure not only protects the optical components inside the device but also ensures stable light propagation and the reliability of the device.

[0082] The design of the light guide device display device provided in this application faces two main challenges: first, how to achieve lossless reflection of incident light across a wide range of wavelengths and incident angles; and second, how to reduce the adverse effects of the sealing structure between the diffraction waveguide layer 2 and the optomechanical system 1 on optical performance. To address these issues, this application introduces a combination of the total internal reflection maintenance layer 5 and the reflective film 4.

[0083] First, to achieve lossless reflection of incident light across a wide range of wavelengths and incident angles, a total internal reflection maintenance layer 5 was designed. The refractive index of this layer 5 is precisely controlled to ensure that the light meets the conditions for total internal reflection at the interface between the diffraction waveguide layer 2 and the maintenance layer 5. Since total internal reflection is a lossless optical process, this design ensures that light does not lose energy due to reflection during propagation, thus achieving lossless reflection across a wide range of wavelengths and incident angles.

[0084] Secondly, to minimize the adverse effects of the sealing structure on optical performance, the dual functions of the total internal reflection maintenance layer 5 and the reflective film 4 are combined. The sealing layer 3 requires a high refractive index material to ensure a good seal, but this increases the critical angle for total internal reflection, causing some incident light at certain angles to easily refract and leak. However, by introducing the total internal reflection maintenance layer 5, an optical environment that satisfies the total internal reflection condition can be reconstructed for the diffraction waveguide layer 2 without altering the sealing layer 3. Even if some light penetrates the diffraction waveguide layer 2 due to the design of the sealing layer 3, the reflective film 4 can act as an additional safeguard, reflecting this light back into the diffraction waveguide layer 2. It is important to note that because the design of the total internal reflection maintenance layer 5 significantly reduces the amount of light that needs to be reflected by the reflective film 4, even if the reflective film 4 has insufficient reflectivity over a wide wavelength range, it will not significantly affect the overall optical performance of the system.

[0085] Figure 2 A schematic diagram of the optical path propagation of a light guide device display device according to an embodiment of this application is provided. (For reference only.) Figure 2 When the diffraction waveguide layer 2 is working normally, light rays a, b, and c can all undergo total internal reflection within it, thus achieving effective propagation of light.

[0086] However, when the optomechanical system 1 and the diffraction waveguide layer 2 are sealed together by the sealing layer 3, the refractive index n1 of the sealing layer 3 is typically greater than that of air, which reduces the range of angles that can support total internal reflection. Specifically, light rays that could normally propagate through total internal reflection within the diffraction waveguide layer 2 may penetrate the diffraction waveguide layer 2 and exit due to the presence of the sealing layer 3; for example, these rays may be rays b and c, resulting in light loss.

[0087] To address this issue, a total reflection maintenance layer 5 is introduced in this application, see [link to application]. Figure 2 The total internal reflection maintenance layer 5 ensures that the angle between light rays b and c (which might otherwise penetrate the diffraction waveguide layer 2 due to the sealing layer 3) still satisfies the total internal reflection condition. Therefore, this portion of the light does not penetrate the total internal reflection maintenance layer 5 but can continue to propagate efficiently within the diffraction waveguide layer 2. In this way, the embodiments of this application effectively reduce the light loss problem caused by the sealing layer 3 and improve the optical performance of the light guide device display.

[0088] Please continue reading Figure 2 Although the design of the total internal reflection maintenance layer 5 solves the problem that most light rays may penetrate the diffraction waveguide layer 2 due to the influence of the sealing layer 3, a small portion of light rays, such as those located between light rays a and b with relatively small incident angles, may not meet the total internal reflection condition of the total internal reflection maintenance layer 5 and will penetrate it. When these rays that have penetrated the total internal reflection maintenance layer 5 encounter the reflective film 4, the high reflectivity characteristics of the reflective film 4 (its reflectivity for visible light can reach over 90%, even as high as 96% or 98%) play a crucial role. The reflective film 4 can effectively reflect this portion of light back into the diffraction waveguide layer 2, thereby avoiding light loss. This design not only ensures efficient light propagation within the diffraction waveguide layer 2 but also further improves the optical efficiency of the entire light guide device display.

[0089] Therefore, through the synergistic effect of the total internal reflection maintenance layer 5 and the reflective film 4, the light guide device display device of this application embodiment solves the light loss problem caused by the sealing layer 3, and realizes efficient and lossless propagation of light within the diffraction waveguide layer 2.

[0090] This application introduces a total reflection maintenance layer 5 as an intermediate layer, which is located between the diffraction waveguide layer 2 and the reflective film 4, significantly improving the total reflection efficiency and optical performance, while solving the energy loss problem caused by sealing.

[0091] In this application, the optical engine 1, the diffraction waveguide layer 2, the sealing layer 3, the reflective film 4, and the total internal reflection maintenance layer 5, together constitute a complete light guide device display device. The sealing layer 3 seals and connects the optical engine 1 to the diffraction waveguide layer 2, solving the problem of dust and moisture intrusion, thereby protecting the optical components from external environmental damage. Simultaneously, the isolation design between the reflective film 4 and the total internal reflection maintenance layer 5 further prevents the sealing layer 3 from directly contacting the total internal reflection area of ​​the diffraction waveguide layer 2, ensuring efficient total internal reflection propagation of light within the diffraction waveguide layer 2. This, in turn, minimizes the adverse effects of the sealing structure on optical performance while maintaining airtightness.

[0092] The light guide device display device provided in this application embodiment can bring at least the following significant effects:

[0093] (1) The introduction of the total reflection maintenance layer 5, with its refractive index lower than that of the sealing layer 3, reconstructs the optical conditions that satisfy the critical angle of total reflection for the diffraction waveguide layer 2. This allows light that would otherwise be easily refracted and leaked due to the high refractive index of the sealing layer 3 to achieve total reflection at the interface between the total reflection maintenance layer 5 and the diffraction waveguide layer 2, thereby significantly reducing the refraction and leakage of light.

[0094] (2) The design of the total reflection maintenance layer 5 greatly reduces the amount of light that needs to be reflected by the reflective film, because most of the light has already achieved total reflection at the interface between the total reflection maintenance layer 5 and the diffraction waveguide layer 2. Therefore, even though the wide-band reflectivity of the reflective film 4 is limited, it can still improve the overall reflectivity of the light guide device for different wavelengths of light.

[0095] (3) The design of the total reflection maintenance layer 5 enables most of the light to propagate through total reflection within the diffraction waveguide layer 2, reducing the number of times the light comes into contact with the reflective film 4. This reduces the potential loss of optical efficiency during reflection and improves the overall optical performance of the light guide device.

[0096] (4) The synergistic effect of the total reflection maintenance layer 5 and the reflective film 4 not only solves the problem of light refraction and leakage, but also optimizes the light propagation path. By controlling the direction and angle of light propagation, more efficient and precise light transmission is achieved.

[0097] Furthermore, because the light guide device of this application can effectively reduce light loss and improve optical efficiency, it can significantly improve the imaging quality of head-mounted display devices. This can bring users a clearer, brighter, and more vibrant visual effect, enhancing the overall user experience.

[0098] See some examples in this application. Figure 2When the incident light propagates in the diffraction waveguide layer 2, the following two situations exist:

[0099] First case: For incident angle θ ≥ θ c The incident light rays are capable of total internal reflection at the first interface, with a FOV of ≥70%;

[0100] The second case: for incident angle θ < θ c The incident light rays can penetrate the total reflection maintenance layer 5 and be reflected back to the diffraction waveguide layer 2 by the reflective film 4;

[0101] Where, θ c =arcsin(n0 / n2), where n2 is the refractive index of the diffraction waveguide layer 2, and n2 and n0 satisfy: n2-n0≥0.4.

[0102] Regarding the first scenario, the details are as follows:

[0103] For incident angle θ≥θ c The incident light rays are designed to undergo total internal reflection at the first interface between the diffraction waveguide layer 2 and the total internal reflection maintenance layer 5. The key here is ensuring that the incident angle θ of this portion of the light rays is greater than or equal to a specific critical angle for total internal reflection θ. c The critical angle for total internal reflection θ c The value is calculated using arcsin(n0 / n2), where n2 is the refractive index of the diffraction waveguide layer 2 and n0 is the refractive index of the total internal reflection maintenance layer 5. Furthermore, by adjusting the refractive index n0 of the total internal reflection maintenance layer 5, efficient total internal reflection can be achieved, ensuring that this portion of the light propagates along the expected path within the diffraction waveguide layer 2.

[0104] It is worth noting that this design strategy covers ≥70% of the field of view (FOV), thus ensuring the excellent optical performance of the light guide device display device at most viewing angles.

[0105] Regarding the second scenario, the details are as follows:

[0106] For the incident angle θ < θ c Incident light rays, not meeting the conditions for total internal reflection at the first interface, will penetrate the total internal reflection maintenance layer 5. However, these rays are not lost. This application utilizes the high reflectivity of the reflective film 4 to reflect these penetrating rays back into the diffraction waveguide layer 2 after encountering the reflective film 4. This design not only effectively avoids light loss but also further improves the optical efficiency of the entire light guide device display. Even though this portion of light accounts for a relatively small proportion (<30% FOV), it still plays an indispensable role in the overall optical performance.

[0107] The light guide device display device in this application example achieves lossless reflection across a wide range of wavelengths and incident angles, and effectively reduces the adverse effects of the sealing layer 3 on optical performance. Specifically, the device not only ensures that most light rays (≥70% FOV) can propagate efficiently within the diffraction waveguide layer 2 through total internal reflection, but also effectively recovers light rays that might penetrate the total internal reflection maintenance layer 5 through the synergistic effect of the reflective film 4. This design not only improves light utilization efficiency but also significantly enhances the overall optical performance of the light guide device display device, providing a clearer and brighter display effect for applications such as head-mounted displays.

[0108] See some examples in this application. Figures 3 to 5 On the vertical projection plane of the total reflection propagation path of the diffraction waveguide layer 2, the projection of the reflective film 4 falls completely within the projection range of the total reflection maintenance layer 5.

[0109] In the examples of this application, the relative positional relationship between the reflective film 4 and the total internal reflection maintenance layer 5 in spatial arrangement is described. Specifically, on the vertical projection plane of the total internal reflection propagation path of the diffraction waveguide layer 2, the projection of the reflective film 4 falls completely within the projection range of the total internal reflection maintenance layer 5. In other words, when viewed from a plane perpendicular to the direction of light propagation, the reflective film 4 is completely covered by the total internal reflection maintenance layer 5. Alternatively, it can be said that the reflective film region between the sealing layer 3 and the total internal reflection propagation region of the diffraction waveguide layer 2 is entirely situated within the region where the total internal reflection maintenance layer 5 is located.

[0110] The layout design described above brings significant technical benefits, specifically:

[0111] Since the reflective film 4 is completely covered by the total internal reflection maintenance layer 5, it can reflect transmitted light without interfering with the normal function of the total internal reflection maintenance layer 5. This arrangement ensures that the total internal reflection propagation path of light within the diffraction waveguide layer 2 is protected to the greatest extent, reducing light loss and thus improving the optical performance of the entire light guide device display device.

[0112] Furthermore, this layout design is more intuitive and easier to implement during the manufacturing process. For example, the total reflection maintenance layer 5 can be deposited or coated first, and then the reflective film 4 can be placed on it without worrying that the reflective film 4 extends beyond the area of ​​the total reflection maintenance layer 5. This not only simplifies the manufacturing process but also improves manufacturing accuracy and consistency.

[0113] It is worth noting that in the total internal reflection propagation region, which is not a light path, the dimensional relationship between the reflective film 4 and the total internal reflection maintenance layer 5 is not subject to the above constraints. This means that in these regions, the reflective film 4 and the total internal reflection maintenance layer 5 can be arranged and adjusted according to actual needs without affecting the light propagation effect in the total internal reflection propagation region.

[0114] In summary, this application achieves efficient propagation and utilization of light in a light guide device display by precisely controlling the relative positional relationships among the sealing layer 3, the diffraction waveguide layer 2, the reflective film 4, and the total internal reflection maintenance layer 5. This design improves the optical performance of the light guide device display.

[0115] See some examples in this application. Figures 9 to 11 The total reflection maintaining layer 5 includes a low-refractive-index material layer 501, the refractive index of which is n0, and n0 is less than 1.3.

[0116] In this example of the application, the total internal reflection maintaining layer 5 is designed to include a low-refractive-index material layer 501, the refractive index n0 of which is designed to be less than 1.3. This design aims to further optimize the optical performance of the light guide device display by controlling the refractive index of the total internal reflection maintaining layer 5.

[0117] In the example provided in this application, this design, which uses a low-refractive-index material layer 501 as at least a portion of the total reflection maintenance layer 5, can bring the following significant technical effects, specifically:

[0118] When the refractive index n0 of the total internal reflection maintaining layer 5 is less than the refractive index n2 of the diffraction waveguide layer 2, and the difference between the two satisfies a certain condition (e.g., n2-n0≥0.4), the total internal reflection propagation condition of the incident light within the diffraction waveguide layer 2 can be maintained more effectively. The refractive index of the low-refractive-index material layer 501 is less than 1.3. Compared with some high-refractive-index diffraction waveguide materials (e.g., optical plastics, glass, etc. with refractive indices greater than 1.4 or higher), it can form a larger refractive index difference with the diffraction waveguide layer 2, thereby enhancing the total internal reflection effect and reducing light reflection loss at the interface.

[0119] In the total internal reflection maintenance layer 5, the use of the low-refractive-index material layer 501 not only improves light efficiency but also has a positive impact on the overall performance of the light guide device display. For example, a lower refractive index means that the material has better light transmittance, lower absorption loss, and less dispersion, all of which contribute to improving the final display effect and color reproduction of the light guide device display.

[0120] Furthermore, by employing a low-refractive-index material layer 501, greater flexibility is gained in selecting the material for the total internal reflection maintenance layer 5. Materials that meet refractive index requirements while also possessing good processability, stability, and cost-effectiveness can be selected, thereby further optimizing the manufacturing cost and performance of the light guide device.

[0121] In the design of the light guide device display device provided in this application embodiment, the selection of the refractive index of the total internal reflection maintaining layer 5 is crucial for maintaining the total internal reflection propagation of light. Theoretically, the lower the refractive index of the low-refractive-index material layer 501, the wider the range of total internal reflection wavelengths and angles it can maintain, which is beneficial to improving the optical performance of the light guide device display device. However, in practical applications, factors such as manufacturing difficulty and material feasibility also need to be considered.

[0122] After comprehensive evaluation, this application selected a material with a refractive index below 1.3 as the low-refractive-index material layer. This design ensures both effectiveness and process feasibility. To achieve this low refractive index, the low-refractive-index material layer 501 can, for example, use a polymer or organic compound as the substrate. By selecting suitable components, optimizing the molecular structure, introducing porous structures, and optimizing optical design, the refractive index of the material can be effectively reduced to below 1.3.

[0123] Specifically, selecting monomers or polymers with low refractive indices as the substrate is fundamental. Building upon this, the refractive index can be further influenced by adjusting the material's molecular structure, such as changing the length of the molecular chains and the degree of branching. Furthermore, introducing porous structures is also an effective method for reducing the refractive index; it can lower the overall refractive index by increasing the air content within the material. Finally, by optimizing the optical design, such as adjusting the thickness and shape of the material layers, precise control of light can be achieved, thereby improving the optical performance of the light guide device.

[0124] See some examples in this application. Figures 9 to 11 The total reflection maintaining layer 5 further includes: a transparent connecting layer 502 and / or a transparent protective layer 503; wherein, the transparent connecting layer 502 is disposed between the diffraction waveguide layer 2 and the low-refractive-index material layer 501, and its refractive index is between the diffraction waveguide layer 2 and the low-refractive-index material layer 501; the transparent protective layer 503 is disposed between the low-refractive-index material layer 501 and the reflective film 4.

[0125] In this example of the application, see Figures 9 to 11 The total reflection maintaining layer 5 includes not only the low-refractive-index material layer 501 in the above example, but may also optionally include a transparent connecting layer 502 and / or a transparent protective layer 503.

[0126] In one example, see Figure 9 The total internal reflection maintaining layer 5 includes a low-refractive-index material layer 501 and a transparent connecting layer 502 stacked together. In this example, the transparent connecting layer 502 is disposed between the diffractive waveguide layer 2 and the low-refractive-index material layer 501, and its refractive index is designed to be between the refractive indices of the diffractive waveguide layer 2 and the low-refractive-index material layer 501. For example, the refractive index of the low-refractive-index material layer 501 is less than 1.3, the refractive index of the diffractive waveguide layer 2 is 1.7 or 2.0, and the refractive index of the transparent connecting layer 502 is, for example, 1.4-1.5. This design aims to ensure that light maintains a smooth transition when passing through the interface of materials with different refractive indices, reducing reflection and scattering, thereby maintaining efficient total internal reflection propagation.

[0127] For example, the transparent bonding layer can be made of transparent OCA (Optically Clear Adhesive) adhesive. This not only ensures a tight bond between the low-refractive-index material layer 501 and the diffractive waveguide layer 2, but also guarantees the stability of optical performance.

[0128] In one example, see Figure 10 The total reflection maintaining layer 5 includes a low-refractive-index material layer 501 and a transparent protective layer 503 stacked together. In this example, the transparent protective layer 503 is disposed between the low-refractive-index material layer 501 and the reflective film 4, aiming to protect the low-refractive-index material layer 501 from corrosion by potentially harmful materials or components present in the reflective film 4. Simultaneously, it ensures a tight bond between the low-refractive-index material layer 501 and the reflective film 4, preventing unnecessary light loss at the interface.

[0129] For example, the transparent protective layer can be made of materials such as silicon oxide, which can form a dense protective film on the low-refractive material layer 501 by means of processes such as vapor deposition, and then the reflective film 4 is vapor deposited on it.

[0130] In one example, see Figure 11 The total internal reflection maintaining layer 5 includes a low-refractive-index material layer 501, a transparent connecting layer 502, and a transparent protective layer 503 stacked together; wherein the low-refractive-index material layer 501 is located between the transparent connecting layer 502 and the transparent protective layer 503. In the provided example, the total internal reflection maintaining layer 5 adopts a composite structure design, specifically including a low-refractive-index material layer 501, a transparent connecting layer 502, and a transparent protective layer 503 stacked together. This design organically combines three layer structures with different functions to form a total internal reflection maintaining layer with excellent optical performance and structural stability.

[0131] In this example, the low-refractive-index material layer 501, located between the transparent connecting layer 502 and the transparent protective layer 503, is the core component of the total internal reflection maintenance layer 5. Its refractive index is lower than that of the diffractive waveguide layer, which helps maintain total internal reflection propagation of light within the diffractive waveguide layer 2, reducing light leakage. By controlling the refractive index of the low-refractive-index material layer 501, the optical performance of the light guide device display can be further optimized. The transparent connecting layer 502, located between the diffractive waveguide layer 2 and the low-refractive-index material layer 501, serves as a physical connection and optical transition. Its refractive index is between that of the diffractive waveguide layer 2 and the low-refractive-index material layer 501, ensuring a smooth transition of light at the interface. The transparent connecting layer 502 can be made of transparent OCA adhesive or similar materials, possessing good processing performance and optical stability. The transparent protective layer 503 is located above the low-refractive-index material layer 501 and is in direct contact with the reflective film 4. Its main function is to protect the low-refractive-index material layer 501 from corrosion by any harmful materials or components that may be present in the reflective film 4. Simultaneously, the transparent protective layer 503 also ensures a tight bond between the low-refractive-index material layer 501 and the reflective film 4, preventing unnecessary light loss at the interface. The transparent protective layer 503 can be made of transparent materials such as silicon oxide and prepared using processes such as vapor deposition.

[0132] In some examples of this application, the thickness of the total reflection maintenance layer 5 is 1 μm to 100 μm.

[0133] In the example of this application, the thickness of the total internal reflection sustaining layer 5 is designed to be in the range of 1 micrometer to 100 micrometers. More preferably, the thickness range of the total internal reflection sustaining layer 5 can be further optimized to 1 micrometer to 50 micrometers. This design aims to balance the blocking effect of the total internal reflection sustaining layer 5 on evanescent waves with the loss of light in the non-total internal reflection region to achieve optimal optical performance. A detailed description follows.

[0134] Total internal reflection generates evanescent waves at the interface, and their amplitude decays exponentially with increasing distance from the interface. To effectively prevent evanescent waves from penetrating the total internal reflection maintenance layer 5 and avoid energy loss, the total internal reflection maintenance layer 5 needs to maintain a certain thickness. Since the penetration depth of evanescent waves typically does not exceed a few wavelengths, choosing a thickness greater than 1 micrometer for the total internal reflection maintenance layer 5 can effectively prevent energy loss caused by evanescent wave penetration.

[0135] At the same time, the total internal reflection maintaining layer 5 should not be too thick. If the thickness is too large, non-total internal reflection light may exit directly from the boundary after entering the total internal reflection maintaining layer 5, see [reference needed]. Figure 6This would cause unnecessary losses. Therefore, choosing a thickness of less than 100 micrometers (more preferably less than 50 micrometers) is more reasonable, as it helps to reduce light loss in the non-total reflection region and improve light utilization and propagation efficiency.

[0136] In the example of this application, this precise control over the thickness of the total reflection maintenance layer 5 brings about the following significant technical effects:

[0137] Optimized optical performance: By controlling the thickness of the total internal reflection sustaining layer 5, the penetration of evanescent waves is effectively prevented and energy loss is avoided, while light loss in the non-total internal reflection region is reduced. This helps improve the optical performance of the light guide device display, giving it higher light utilization and propagation efficiency.

[0138] Enhanced structural stability: An appropriate thickness of the total reflection maintenance layer 5 helps to enhance the stability of the structure, enabling the light guide device display device to maintain stable optical performance during long-term use.

[0139] In summary, by controlling the thickness of the total reflection maintenance layer 5, this application achieves effective blocking of evanescent waves and reduction of light loss, thereby improving the optical performance and structural stability of the light guide device display device.

[0140] In some examples of this application, the reflective film 4 is a single-layer metal film, a multilayer dielectric film, or a metal-dielectric composite film; the reflective film 4 has a reflectivity of ≥90% in the visible light band.

[0141] In the examples of this application, the reflective film 4 is designed with various material combinations and structural forms to meet different optical performance requirements. Specifically, the reflective film 4 can be a single-layer metal film, a multi-layer dielectric film, or a metal-dielectric composite film. These designs aim to achieve high reflectivity of the reflective film 4 in the visible light band, requiring a reflectivity ≥90%, in order to minimize light loss and improve the optical efficiency of the light guide device display equipment.

[0142] In one example, the reflective film 4 is a single-layer metal film, such as silver or aluminum, which is widely used due to its excellent optical reflectivity and good electrical conductivity. However, metal films are susceptible to oxidation and moisture corrosion, and therefore may require an additional protective layer (such as silicon oxide) to extend their service life.

[0143] In one example, the reflective film 4 is a multilayer dielectric film. By designing the thickness and refractive index of each dielectric layer, high reflectivity can be achieved within a specific wavelength and angle range. This design offers greater flexibility and adjustability, allowing for customized design based on actual needs.

[0144] In one example, the reflective film 4 is a metal-dielectric composite film: combining the advantages of metal films and multilayer dielectric films, the reflectivity can be further improved and the reflection band broadened through the alternating superposition of metal and dielectric. This design not only has excellent reflective performance, but also effectively resists oxidation and water vapor erosion, improving the durability of the reflective film.

[0145] High-reflectivity reflective films can minimize light loss and improve the optical efficiency of light guide device display equipment. Whether in the design of single-layer metal films, multi-layer dielectric films, or metal-dielectric composite films, a reflectivity of ≥90% can be achieved, providing stable and efficient optical support for optical display equipment. By adopting a combination design of metal and dielectric or adding a protective layer, oxidation and moisture erosion can be effectively resisted, extending the service life of the reflective film. This is of great significance for the long-term stable operation of light guide device display equipment. Furthermore, the diverse reflective film designs allow the light guide device display equipment of this application to adapt to different application scenarios and needs.

[0146] See some examples in this application. Figure 1 , Figure 7 and Figure 8 The sealing layer 3 is an optically transparent adhesive, and the sealing layer 3 is disposed around the gap between the optomechanical system 1 and the diffraction waveguide layer 2.

[0147] See Figure 1 The sealing layer 3, for example, is an optically transparent adhesive and is disposed around the gap between the optomechanical system 1 and the diffraction waveguide layer 2. This design aims to ensure that the sealing layer 3 effectively isolates and protects the internal components from external environmental influences without affecting the normal propagation of light.

[0148] Specifically, the optically transparent adhesive, used as the material of the sealing layer 3, possesses excellent light transmittance and adhesion properties. It can tightly adhere to the gap between the optomechanical system 1 and the diffraction waveguide layer 2, forming an effective sealing barrier to prevent external contaminants such as moisture and dust from entering the device, thereby protecting critical components such as the optomechanical system 1 and the diffraction waveguide layer 2 from damage. Simultaneously, due to the good light transmittance of the optically transparent adhesive itself, it does not significantly obstruct the propagation of light, thus ensuring the normal optical performance of the light guide device display.

[0149] Furthermore, in this application, by tightly adhering to the gap between the optomechanical system 1 and the diffraction waveguide layer 2, the optically transparent adhesive sealing layer effectively prevents external contaminants from entering the device, thereby reducing the equipment failure rate caused by contamination and improving the overall reliability of the device. The optically transparent adhesive itself has good light transmittance and will not significantly obstruct the propagation of light. Therefore, while ensuring the sealing effect, it also ensures the normal optical performance of the light guide device display, avoiding the problem of decreased optical performance due to improper selection of sealing layer materials. Using optically transparent adhesive as the sealing layer material simplifies the manufacturing process. Compared with traditional sealing methods, the optically transparent adhesive sealing layer does not require complex mechanical sealing structures or additional sealing treatment steps, reducing manufacturing costs and production cycle.

[0150] The design of the optically transparent adhesive sealing layer enables the light guide device display device of this application to better adapt to various complex application environments. It maintains stable performance and a long service life under conditions of high humidity, high dust, or other harsh conditions.

[0151] It should be noted that the technical solution of this application has a high degree of flexibility and adaptability. It is not only suitable for the arrangement where the optical axis of the optomechanical 1 is perpendicular to the plane where the diffraction waveguide layer 2 is located, see also... Figure 1 This technical solution can also be applied to scenarios where the optical axis of the optomechanical 1 is tilted relative to the plane of the diffraction waveguide layer 2, see [link to relevant documentation]. Figure 8 This application does not impose any restrictions on this type of layout.

[0152] See some examples in this application. Figures 3 to 5 The diffraction waveguide layer 2 includes the following elements:

[0153] A coupling grating 201 is disposed in the first region of the diffraction waveguide layer 2 and configured to couple the incident light emitted by the optomechanical 1 into the diffraction waveguide layer 2.

[0154] A coupling grating 202 is disposed in the second region of the diffraction waveguide layer 2 and configured to couple out light rays that propagate by total internal reflection within the diffraction waveguide layer 2.

[0155] The total reflection sustaining layer 5 covers at least the light propagation path connecting the first region and the second region, and around the coupling grating 201, the total reflection sustaining layer 5 also forms a total reflection sustaining region that at least partially surrounds the coupling grating 201.

[0156] See Figures 3 to 5The diffraction waveguide layer 2 includes key components such as the coupling grating 201 and the coupling grating 202, and works in conjunction with the total internal reflection maintenance layer 5. The synergistic effect of these components enables light to be efficiently coupled into, propagated, and coupled out of the diffraction waveguide layer 2, thereby realizing the display function of the light guide device display device.

[0157] The coupling grating 201 is disposed in the first region of the diffraction waveguide layer 2, and its main function is to couple the incident light emitted by the optomechanical system 1 into the diffraction waveguide layer 2. By designing the structural parameters of the coupling grating (such as grating pitch and depth), efficient light coupling can be achieved and light loss can be reduced.

[0158] The coupling grating 202 is disposed in the second region of the diffraction waveguide layer 2 and is configured to couple and output light rays propagating through total internal reflection. The design of the coupling grating 202 also needs to consider the matching of structural parameters with light propagation characteristics to ensure that the light rays can be coupled and output in a predetermined direction and angle to meet display requirements.

[0159] The total internal reflection sustaining layer 5 at least covers the optical propagation path connecting the coupling grating 201 and the output grating 202. Under the action of the total internal reflection sustaining layer 5, light can maintain total internal reflection propagation within the diffraction waveguide layer 2, reducing light leakage. Specifically, around the coupling grating 201, the total internal reflection sustaining layer 5 forms a total internal reflection sustaining region that at least partially surrounds the coupling grating. This design aims to further reduce light loss during the coupling process and improve light coupling efficiency.

[0160] In one example, see Figure 3 and Figure 4 The total internal reflection maintaining layer 5 is disposed around the periphery of the coupling grating 201, and the reflective film 4 is disposed within the region of the total internal reflection maintaining layer 5. Specifically, see [link to documentation]. Figure 3 The total reflection sustaining layer 5 has a circular ring structure. (See also...) Figure 4 The total reflection maintenance layer 5 has a square ring structure.

[0161] In one example, see Figure 5 The total reflection maintenance layer 5 partially surrounds the periphery of the coupling grating 201, forming a semi-circular ring structure, and the reflective film 4 is disposed in the region of the total reflection maintenance layer 5.

[0162] It should be noted that the most important aspect of the reflection maintenance layer 5 is that it is located on the total internal reflection optical path between the coupled-in grating 201 and the coupled-out grating 202, and its specific shape can be flexibly designed as needed.

[0163] In this application, by precisely designing the structural parameters of the coupling grating 201 and the total internal reflection maintenance layer 5, efficient coupling of light into the diffraction waveguide layer 2 is achieved. Simultaneously, the total internal reflection maintenance region formed around the coupling grating 201 by the total internal reflection maintenance layer 5 further reduces light loss during coupling, improving overall light coupling efficiency. The total internal reflection maintenance layer 5 at least covers the light propagation path connecting the coupling grating 201 and the output grating 202, ensuring that light can maintain total internal reflection propagation within the diffraction waveguide layer 2. This design reduces light leakage, improves light utilization, and enables the light guide device display device to have higher optical performance.

[0164] This diffractive waveguide layer design, featuring efficient light coupling and optimized light propagation paths, enables light guide devices for display applications to be widely used in various scenarios. Whether under high-brightness, high-resolution display requirements or in environments demanding long-term stable operation, it maintains excellent performance.

[0165] See some examples in this application. Figure 3 and Figure 5 The diffraction waveguide layer 2 further includes a folding grating 203, which is located on the light propagation path between the input grating 201 and the output grating 202.

[0166] See Figure 3 and Figure 5 In addition to the previously mentioned coupling grating 201 and coupling grating 202, the diffraction waveguide layer 2 also incorporates a transition grating 203. The transition grating 203 is located on the light propagation path between the coupling grating 201 and the coupling grating 202, and its function is to change the propagation direction of the light, enabling the light to propagate efficiently within the diffraction waveguide layer 2 along a predetermined path.

[0167] The deflection grating 203, as a component in the diffraction waveguide layer 2, primarily functions to deflect the direction of light. By designing the structural parameters of the deflection grating 203, such as the grating pitch and tilt angle, precise control over the direction of light propagation can be achieved. This design allows light to propagate more flexibly and efficiently within the diffraction waveguide layer, further enhancing the optical performance of the light guide device display.

[0168] When the coupled-out grating 202 is designed as a one-dimensional grating, see [reference needed]. Figure 3 and Figure 5A deflection grating 203 is added to the optical path between the coupling grating 201 and the output grating 202. This design allows light to first enter the diffraction waveguide layer 2 through the coupling grating 201 during propagation, then change its propagation direction under the action of the deflection grating 203, and finally be coupled out through the output grating 202. During this process, the total internal reflection maintenance layer 5 is located on the total internal reflection optical path between the coupling grating 201 and the deflection grating 203, ensuring that the light can maintain total internal reflection propagation and reducing light leakage.

[0169] However, the situation is different when the coupling grating 202 is designed as a two-dimensional grating. See also Figure 4 Because two-dimensional gratings have a more complex structure, enabling coupled output of light in multiple directions, the deflection grating 203 can be omitted. In this case, after light enters the diffraction waveguide layer 2 through the coupling grating 201, it will propagate directly along the total internal reflection path to the coupling grating 202 and be coupled out. The total internal reflection maintenance layer 5 still covers the critical light propagation path to ensure the total internal reflection propagation of light.

[0170] This design adjustment for different types of coupling gratings 202 not only optimizes the structure of the diffraction waveguide layer 2, but also improves the optical performance and flexibility of the light guide device display device.

[0171] See some examples in this application. Figure 1 The light guide device display device further includes a protective layer 6, which is disposed on the side of the diffraction waveguide layer 2 where the coupling grating 201 and the coupling grating 202 are located, and an air gap is formed between the protective layer 6 and the diffraction waveguide layer 2.

[0172] The light guide device display device provided in this application embodiment may include a protective layer 6 in addition to the previously mentioned key components. See also Figure 1 This design aims to further enhance the stability and durability of light guide device display devices, while optimizing their optical performance.

[0173] The main function of the protective layer 6 is to protect the main optical components on the diffraction waveguide layer 2 from damage caused by the external environment. It can be made of materials with high light transmittance and wear resistance, such as optical glass or high light transmittance plastics. The protective layer 6 not only effectively prevents the diffraction waveguide layer from physical damage such as scratches and impacts, but also reduces performance changes caused by environmental factors (such as humidity and temperature).

[0174] The air gap formed between the protective layer 6 and the diffraction waveguide layer 2 plays a crucial role. Air, as an excellent insulator and a low-refractive-index medium, effectively isolates the direct contact between the protective layer 6 and the diffraction waveguide layer, reducing light loss and performance degradation caused by material interface effects. Simultaneously, the presence of the air gap also helps maintain stable light propagation within the diffraction waveguide layer, improving the overall optical performance of the light guide device display.

[0175] See Figure 12 In this example, a beam propagation characteristic of a single green 30° (FOV) diffractive waveguide layer 2 is provided. This diffractive waveguide layer 2 uses a high-refractive-index material (refractive index 1.7) and is paired with a low-refractive-index low-refractive-index material layer 501 (as a total internal reflection maintenance layer 5, with a refractive index of 1.3). When light is coupled into the diffractive waveguide layer 2 through a coupling grating 201 on the diffractive waveguide layer 2, its propagation path is modulated. The specific description is as follows:

[0176] Total internal reflection region: Light rays in most of the field of view (FOV) region lie between the outer ring of the diffraction waveguide layer 2 and the corresponding dashed coil of the low-refractive material layer 501. In this region, light rays can maintain total internal reflection and propagate along the diffraction waveguide layer 2 without energy loss.

[0177] Transmission and Reflection Region: Only a small portion of the light in the FOV region lies between the inner circle of the diffraction waveguide layer 2 and the corresponding dotted circle of the low-refractive material layer 501. This portion of the light penetrates the total internal reflection maintenance layer 5, reaches the reflective film 4, and after being reflected by the reflective film 4, returns to the diffraction waveguide layer 2 to continue propagating.

[0178] This design enables precise control of the light propagation path, ensuring that light can propagate efficiently to the target area while reducing unnecessary energy loss.

[0179] See Figure 13 This example demonstrates the beam propagation characteristics of an RGB full-color 30° diffraction waveguide layer. The diffraction waveguide layer 2 is designed using a high-refractive-index material (refractive index 2.0), coupled with a low-refractive-index low-refractive-index material layer 501 (serving as a total internal reflection maintenance layer 5, with a refractive index of 1.3). A detailed description follows:

[0180] Total Internal Reflection Region: For most of the FOV region of green and red light, and part of the FOV region of blue light, the light rays are located between the outer ring of the diffraction waveguide layer 2 and the corresponding dashed coil of the low-refractive material layer 501. In this region, the light rays can also maintain a state of total internal reflection and propagate along the waveguide without energy loss.

[0181] Penetration and reflection areas: with Figure 12 Unlike the monochromatic waveguide shown, Figure 13 In the full-color waveguide, a portion of the blue light's field of view (FOV) lies between the inner circle of the diffraction waveguide layer 2 and the corresponding dotted coil of the low-refractive material layer 501. This portion of light also penetrates the total internal reflection maintenance layer 5, reaches the reflective film 4, and returns to the diffraction waveguide layer 2 after reflection.

[0182] It is worth noting that the design of a full-color waveguide is more complex because it needs to process red, green, and blue light simultaneously. However, by adjusting the parameters of key components such as the diffraction waveguide layer 2, the low-refractive-index material layer 501, and the reflective film 4, the full-color waveguide also achieves control over the light propagation path, ensuring that the light can propagate efficiently to the target area and present a rich color effect.

[0183] According to another embodiment of this application, a head-mounted display device is provided, the head-mounted display device including a housing and a light guide device as described above.

[0184] According to another embodiment of this application, a method for fabricating a light guide device display device is provided, see [link to relevant documentation]. Figure 1 The preparation method includes the following steps 100 to 300:

[0185] Step 100: Form a total reflection sustaining layer 5 on the diffraction waveguide layer 2, wherein the total reflection sustaining layer 5 at least partially covers the total reflection propagation region of the diffraction waveguide layer 2;

[0186] Step 200: Form a reflective film 4 on the total reflection maintenance layer 5, such that the total reflection maintenance layer 5 is still located between the diffraction waveguide layer 2 and the reflective film 4;

[0187] Step 300: Form a sealing layer 3 on the reflective film 4, and connect the optomechanical system 1 to the sealing layer 3 to seal the connection between the optomechanical system 1 and the diffraction waveguide layer 2.

[0188] Wherein, the refractive index n0 of the total reflection maintaining layer 5 is lower than the refractive index n1 of the sealing layer 3, and in the presence of the sealing layer 3, the total reflection maintaining layer 5 reconstructs the diffraction waveguide layer 2 to satisfy the critical angle θ of total reflection. c The optical conditions, and the total internal reflection sustaining layer 5 includes: a first interface combined with the diffraction waveguide layer 2, for establishing the total internal reflection critical angle θ. c The optical conditions; and the second interface combined with the reflective film 4, used to control the reflection of light at a specific angle.

[0189] Step 100 above involves forming a total reflection sustaining layer 5 on the diffraction waveguide layer 2. Specifically:

[0190] In the first key step of fabricating a light guide device display, a total reflection maintenance layer 5 needs to be formed on the surface of the diffraction waveguide layer 2. Thin film deposition techniques, such as electron beam evaporation, sputtering deposition, or chemical vapor deposition, can be used in this step.

[0191] The main function of the total internal reflection maintenance layer 5 is to ensure that incident light can maintain total internal reflection propagation within the diffraction waveguide layer 2, reducing the penetration of incident light through the diffraction waveguide layer 2, thereby reducing light loss and ultimately improving the optical performance of the light guide device display. Specifically, by controlling deposition parameters such as deposition rate, temperature, and atmosphere, a total internal reflection maintenance layer with excellent optical performance and stability can be obtained.

[0192] Step 200 above involves forming a reflective film 4 on the total reflection maintenance layer 5. Specifically:

[0193] After forming the total reflection maintenance layer 5, a reflective film 4 needs to be further formed on its surface. The main function of the reflective film 4 is to reflect light, ensuring that light can propagate and couple efficiently within the diffraction waveguide layer 2. This step can also use, for example, thin film deposition techniques, and control the deposition parameters to obtain the desired reflectivity and optical performance. The material selection for the reflective film 4 depends on the required spectral range and reflection performance requirements, and materials include metals (such as aluminum, silver, etc.) and multilayer dielectric films.

[0194] Step 300 above involves forming a sealing layer 3 on the reflective film 4 and connecting the optomechanical system 1 to the sealing layer 3 to seal the optomechanical system 1 and the diffraction waveguide layer 2 (the main purpose is to seal the gap between the optomechanical system 1 and the diffraction waveguide layer 2). Specifically:

[0195] After the reflective film 4 is deposited, the sealing layer 3 is coated onto the reflective film 4 and fixedly connected to the optomechanical system 1. The main function of the sealing layer 3 is to seal the gap between the optomechanical system 1 and the diffraction waveguide layer 2, preventing external moisture, dust, and other contaminants from entering the device and affecting its optical performance and stability. Simultaneously, the sealing layer 3 also needs to possess a certain degree of flexibility and adhesion to ensure a good sealing effect under different temperature and humidity conditions. This step typically involves using high-precision coating techniques and curing processes to ensure that the sealing layer adheres uniformly and firmly to the reflective film 4 and the optomechanical system 1.

[0196] In summary, the light guide device display device fabrication method of this application achieves precise fabrication and assembly of the total reflection maintenance layer 5, the reflective film 4, and the sealing layer 3 by precisely controlling the deposition parameters and process conditions of each step.

[0197] According to another embodiment of this application, a sealing structure for a light guide device display device is provided, see [link to relevant documentation]. Figure 1 and Figure 2 The sealing structure includes the following structural layers:

[0198] Total reflection maintenance layer 5 is disposed on the diffraction waveguide layer 2 and at least covers the total reflection propagation region of the diffraction waveguide layer 2; wherein, the total reflection maintenance layer 5 includes a low-refractive-index material layer 501, and the refractive index of the low-refractive-index material layer 501 is less than 1.3, and the thickness of the total reflection maintenance layer 5 is 1μm to 100μm;

[0199] A reflective film 4 is disposed on the total reflection maintenance layer 5, such that the total reflection maintenance layer 5 is also located between the diffraction waveguide layer 2 and the reflective film 4;

[0200] A sealing layer 3 is disposed on the reflective film 4 and connected to the optomechanical system 1. The sealing layer 3 is used to seal the connection between the optomechanical system 1 and the diffraction waveguide layer 2.

[0201] Wherein, the refractive index n0 of the total reflection maintaining layer 5 is lower than the refractive index n1 of the sealing layer 3, and in the presence of the sealing layer 3, the total reflection maintaining layer 5 reconstructs the diffraction waveguide layer 2 to satisfy the critical angle θ of total reflection. c The optical conditions, and the total internal reflection sustaining layer 5 includes: a first interface combined with the diffraction waveguide layer 2, for establishing the total internal reflection critical angle θ. c The optical conditions; and the second interface combined with the reflective film 4, for controlling the reflection of light at a specific angle.

[0202] The sealing structure provided in this application embodiment, by combining a multi-layer structure including a total reflection maintenance layer 5, a reflective film 4, and a sealing layer 3, achieves multiple functions such as efficient light guidance, reflection, and sealing protection. In practical applications, this sealing structure can be widely used in various optical display devices, such as AR / VR helmets and smart glasses, to provide users with a clearer, more detailed, and stable visual experience.

[0203] The specific implementation methods of the head-mounted display device, the light guide device display device, and the sealing structure for the light guide device display device in this application can be referred to the various embodiments of the light guide device display device described above. Therefore, they have at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0204] 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.

[0205] 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 display device, characterized in that, include: Optical mechanism (1), used to provide incident light; A diffraction waveguide layer (2) for transmitting the incident light beam includes a coupling grating (201) and a coupling grating (202). The coupling grating (201) is disposed in a first region of the diffraction waveguide layer (2) and configured to couple the incident light beam emitted by the optomechanical unit (1) into the diffraction waveguide layer (2). The coupling grating (202) is disposed in a second region of the diffraction waveguide layer (2) and configured to couple the light beam propagating by total internal reflection within the diffraction waveguide layer (2) outward. A sealing layer (3) is used to seal the connection between the optomechanical system (1) and the diffraction waveguide layer (2); A reflective film (4) is disposed between the sealing layer (3) and the diffraction waveguide layer (2); A total reflection maintenance layer (5) is disposed between the diffraction waveguide layer (2) and the reflective film (4), and at least partially covers the total reflection propagation region of the diffraction waveguide layer (2); The total reflection sustaining layer (5) has a refractive index n0 lower than that of the sealing layer (3). The total reflection sustaining layer (5) is configured to reconstruct the diffraction waveguide layer (2) to satisfy the critical angle θ of total reflection in the presence of the sealing layer (3). c The optical conditions, and the total internal reflection maintaining layer (5) includes: The first interface, which is combined with the diffraction waveguide layer (2), is used to establish the critical angle θ of total internal reflection. c Optical conditions; and The second interface, combined with the reflective film (4), is used to control the reflection of light at a specific angle.

2. The light guide device display device according to claim 1, characterized in that, When the incident light propagates in the diffraction waveguide layer (2): For incident angle θ≥θ c The incident light rays are capable of total internal reflection at the first interface, with a FOV of ≥70%; For the incident angle θ < θ c The incident light rays can penetrate the total reflection maintenance layer (5) and be reflected back to the diffraction waveguide layer (2) by the reflective film (4); Where, θ c =arcsin(n0 / n2), where n2 is the refractive index of the diffraction waveguide layer (2), and n2 and n0 satisfy: n2-n0≥0.

4.

3. The light guide device display device according to claim 1, characterized in that, On the vertical projection plane of the total reflection propagation path of the diffraction waveguide layer (2), the projection of the reflective film (4) falls completely within the projection range of the total reflection maintenance layer (5).

4. The light guide device display device according to claim 1 or 2, characterized in that, The total reflection maintenance layer (5) includes a low-refractive-index material layer (501) with a refractive index of n0, and n0 is less than 1.

3.

5. The light guide device display device according to claim 4, characterized in that, The total reflection maintenance layer (5) further includes: A transparent connecting layer (502) is disposed between the diffraction waveguide layer (2) and the low-refractive-index material layer (501), and its refractive index is between that of the diffraction waveguide layer (2) and the low-refractive-index material layer (501); and / or, A transparent protective layer (503) is disposed between the low-refractive material layer (501) and the reflective film (4).

6. The light guide device display device according to claim 1, characterized in that, The thickness of the total reflection maintenance layer (5) is 1 μm to 100 μm.

7. The light guide device display device according to claim 1, characterized in that, The reflective film (4) is a single-layer metal film, a multilayer dielectric film, or a metal-dielectric composite film; The reflective film (4) has a reflectivity of ≥90% in the visible light band.

8. The light guide device display device according to claim 1, characterized in that, The sealing layer (3) is an optically transparent adhesive, and the sealing layer (3) is disposed around the gap between the optomechanical unit (1) and the diffraction waveguide layer (2).

9. The light guide device display device according to claim 1, characterized in that, The total reflection sustaining layer (5) covers at least the light propagation path connecting the first region and the second region, and on the periphery of the coupling grating (201), the total reflection sustaining layer (5) forms a total reflection sustaining region that at least partially surrounds the coupling grating (201).

10. The light guide device display device according to claim 9, characterized in that, The diffraction waveguide layer (2) further includes a folding grating (203), which is located on the optical propagation path between the input grating (201) and the output grating (202).

11. The light guide device display device according to claim 9, characterized in that, The light guide device display device further includes a protective layer (6), which is disposed on the side of the diffraction waveguide layer (2) where the coupling grating (201) and the coupling grating (202) are provided, and an air gap is formed between the protective layer (6) and the diffraction waveguide layer (2).

12. A head-mounted display device, characterized in that, include: shell; and The light guide device display device as described in any one of claims 1-11.

13. A method for fabricating a light guide device display device, characterized in that, include: A total reflection sustaining layer (5) is formed on the diffraction waveguide layer (2), and the total reflection sustaining layer (5) at least partially covers the total reflection propagation region of the diffraction waveguide layer (2); A reflective film (4) is formed on the total reflection maintenance layer (5), such that the total reflection maintenance layer (5) is also located between the diffraction waveguide layer (2) and the reflective film (4); A sealing layer (3) is formed on the reflective film (4), and the optomechanical unit (1) is connected to the sealing layer (3) to seal the optomechanical unit (1) to the diffraction waveguide layer (2). The refractive index n0 of the total reflection sustaining layer (5) is lower than the refractive index n1 of the sealing layer (3). In the presence of the sealing layer (3), the total reflection sustaining layer (5) reconstructs the diffraction waveguide layer (2) to satisfy the critical angle θ of total reflection. c The optical conditions, and the total internal reflection sustaining layer (5) includes: a first interface combined with the diffraction waveguide layer (2), for establishing the total internal reflection critical angle θ c The optical conditions; and the second interface combined with the reflective film (4) for controlling the reflection of light at a specific angle.

14. A sealing structure for a light guide device display device, characterized in that, include: A total reflection maintenance layer (5) is disposed on the diffraction waveguide layer (2) and at least covers the total reflection propagation region of the diffraction waveguide layer (2); A reflective film (4) is disposed on the total reflection maintenance layer (5), such that the total reflection maintenance layer (5) is also located between the diffraction waveguide layer (2) and the reflective film (4); A sealing layer (3) is disposed on the reflective film (4) and connected to the optomechanical unit (1). The sealing layer (3) is used to seal the connection between the optomechanical unit (1) and the diffraction waveguide layer (2). The refractive index n0 of the total reflection sustaining layer (5) is lower than the refractive index n1 of the sealing layer (3). In the presence of the sealing layer (3), the total reflection sustaining layer (5) reconstructs the diffraction waveguide layer (2) to satisfy the critical angle θ of total reflection. c The optical conditions, and the total internal reflection sustaining layer (5) includes: a first interface combined with the diffraction waveguide layer (2), for establishing the total internal reflection critical angle θ c The optical conditions; and the second interface combined with the reflective film (4) for controlling the reflection of light at a specific angle.

15. The sealing structure according to claim 14, characterized in that, The total reflection maintenance layer (5) includes a low-refractive-index material layer (501), and the refractive index of the low-refractive-index material layer (501) is less than 1.

3. The thickness of the total reflection maintenance layer (5) is 1 μm to 100 μm.

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