Light guide device and optical display apparatus

Abstract

The embodiment of the invention provides a light guide device and optical display equipment. The light guide device comprises a waveguide layer, a protective layer and at least one multifunctional film layer, the waveguide layer is provided with a first surface facing the protective layer, and the first surface is provided with a grating structure; the protective layer and the waveguide layer are arranged oppositely and at an interval; the multifunctional film layer is arranged between the waveguide layer and the protective layer; wherein the multifunctional film layer is arranged on the first surface of the waveguide layer, and / or the surface, facing the waveguide layer, of the protective layer; the multifunctional film layer comprises a film layer A and a film layer B covering the film layer A, and the film layer B and the film layer A meet a preset refractive index relation so as to form an anti-reflection structure on the surface of the light guide device.

Description

Technical Field

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

[0002] Diffractive waveguides, especially resin waveguides, are core optical components for image transmission and coupling in current near-eye display devices. Traditional waveguide architectures typically combine the waveguide layer and protective layer using a frame-mount method. However, this optical architecture suffers from two significant technical drawbacks: First, the optical performance of this optical architecture is not ideal. Its overall transmittance is low, and due to the existence of multiple interfaces with significant differences in refractive index between the waveguide layer, air gap, and protective layer, strong Fresnel reflections are induced. This not only causes light energy loss but also creates severe background glare behind the light guide device, significantly reducing the contrast, sharpness, and visual comfort of the image display.

[0003] Secondly, it suffers from serious deficiencies in mechanical durability, particularly in its resistance to wiping. During routine cleaning and maintenance, especially during necessary pressing and wiping, the protective layer is prone to deformation, leading to direct contact and friction between it and the precision micro / nano grating structure on the waveguide layer surface. This direct physical contact easily causes irreversible mechanical damage such as scratches and abrasions to the grating, directly affecting optical performance and reducing product yield.

[0004] Therefore, there is an urgent need in this field for a novel waveguide architecture that can effectively optimize its optical performance, achieve high transmittance and low glare, significantly improve the mechanical durability of the device, and fundamentally solve the problem of wiping damage. Summary of the Invention

[0005] The purpose of this application is to provide a new technical solution for a light guide device and an optical display device, which aims to solve at least one of the following problems: light energy loss and insufficient transmittance caused by interface reflection, the resulting background glare interfering with the imaging quality, and grating damage caused by contact friction during wiping.

[0006] In a first aspect, embodiments of this application provide a light guide device, the light guide device comprising: A waveguide layer having a first surface facing the protective layer, on which a grating structure is provided; A protective layer, disposed opposite to and spaced apart from the waveguide layer; and, At least one multifunctional film layer is disposed between the waveguide layer and the protective layer; The multifunctional film layer is disposed on the first surface of the waveguide layer, and / or the protective layer faces the surface of the waveguide layer; The multifunctional film layer includes film layer A and film layer B covering it. Film layer B and film layer A satisfy a preset refractive index relationship to form an anti-reflection and anti-reflection structure on the surface of the light guide device.

[0007] Optionally, film layer A is a dielectric film layer, film layer B is an anti-fingerprint AF film layer, and the refractive index of the anti-fingerprint AF film layer is less than the refractive index of the dielectric film layer in direct contact with it.

[0008] Optionally, the refractive index of the anti-fingerprint AF film is less than or equal to 1.4.

[0009] Optionally, the multifunctional film layer is configured such that the surface reflectivity of the light guide device is ≤2% and the transmittance is ≥98% in the visible light band.

[0010] Optionally, the protective layer has a support pillar layer on the surface facing the waveguide layer, the support pillar layer comprising a plurality of discretely distributed micron-sized pillars; The multifunctional film layer disposed on the protective layer covers the support column layer and the adjacent area. The support column layer and the multifunctional film layer covering it together form a rub-resistant structure to prevent damage caused by friction between the protective layer and the grating structure due to wiping and pressing.

[0011] Optionally, the refractive index n of the micrometer-scale column p With respect to the refractive index n of the protective layer cover Satisfying the relation: |n p –n cover |≤0.3.

[0012] Optionally, the cross-sectional diameter of the micron-sized column is less than 2 μm and its height is less than 20 μm.

[0013] Optionally, the dielectric film layer is a single-layer structure, and its refractive index is less than that of the substrate to which it is attached, wherein the substrate is the grating structure or the protective layer.

[0014] Optionally, the dielectric film layer is a multilayer structure, comprising at least one high refractive index layer and at least one low refractive index layer alternately stacked, and the difference in refractive index between the high refractive index layer and the low refractive index layer is not less than 0.3; Wherein, the refractive index of the low refractive index layer is less than the refractive index of the substrate to which it is attached, and the substrate is the grating structure or the protective layer.

[0015] Optionally, the dielectric film layers of the multilayer structure disposed on the waveguide layer are arranged in the order of low refractive index layer followed by high refractive index layer from the grating structure outward; The dielectric film layers disposed on the protective layer are arranged in the following order from the protective layer outward: first a high refractive index layer, then a low refractive index layer.

[0016] Optionally, the anti-fingerprint AF film layer comprises at least one of a fluoropolymer, a siloxane polymer, or a nano-silica composite.

[0017] Optionally, the surface morphology of the multifunctional film layer on the waveguide layer is conformal to the grating structure or is planar; The multifunctional membrane layer on the protective layer covers the support column layer and forms a plane.

[0018] Secondly, embodiments of this application provide an optical display device, the optical display device comprising: An image source is configured to provide image light; and, As described in the first aspect, the light guide device is configured to receive and conduct the image light provided by the image source and couple the image light into the user's field of view.

[0019] The beneficial effects of this application are as follows: The light guide device provided in this application embodiment constitutes a highly efficient anti-reflection and anti-reflection structure by setting a multifunctional film layer on the corresponding surface of the waveguide layer and / or protective layer. This multifunctional film layer covers the stacked structure of film layer A through film layer B and satisfies the optical relationship that the refractive index of film layer B is less than that of film layer A. This anti-reflection and anti-reflection structure effectively suppresses Fresnel reflection at multiple interfaces such as the surface of the waveguide layer, the surface of the protective layer, and the air gaps between them by establishing an optimized refractive index gradient transition at key optical interfaces. This minimizes the light energy reflection loss caused by the abrupt change in refractive index, thereby significantly improving the overall optical transmittance of the device and eliminating background glare interference.

[0020] 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

[0021] 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.

[0022] Figure 1 This is a schematic diagram of the structure of a traditional light guide device; Figure 2 A schematic diagram of the optical path that generates glare in traditional light guide devices; Figure 3 This is one of the structural schematic diagrams of the light guide device according to an embodiment of this application; Figure 4 This is a second schematic diagram of the structure of the light guide device according to an embodiment of this application; Figure 5 This is the third schematic diagram of the structure of the light guide device according to an embodiment of this application; Figure 6 This is the fourth schematic diagram of the structure of the light guide device according to an embodiment of this application; Figure 7 The reflectivity distribution characteristics of traditional light guide devices under different incident angles; Figure 8 The transmittance distribution characteristics of traditional light guide devices under different incident angles; Figure 9 The reflectance spectrum curve of a traditional light guide device when incident in the visible light band. Figure 10 This is the transmittance spectrum curve of a traditional light guide device when incident in the visible light band. Figure 11 The reflectivity distribution characteristics of the light guide device in the embodiments of this application under different incident angles; Figure 12 The transmittance distribution characteristics of the light guide device in the embodiments of this application under different incident angles; Figure 13 This is the reflectance spectrum curve of the light guide device according to the embodiment of this application when incident in the visible light band; Figure 14 This is the transmittance spectrum curve of the light guide device in the embodiment of this application when incident in the visible light band.

[0023] Explanation of reference numerals in the attached figures: 1. Waveguide layer; 11. First surface; 12. Second surface; 13. Grating structure; 2. Protective layer; 21. Micrometer-scale columnar structure; 3. Multifunctional film layer; 31. Dielectric film layer; 32. Anti-fingerprint AF film layer; 4. First antireflective membrane; 5. Second antireflective membrane. Detailed Implementation

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] The light guide device and optical display device provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0030] According to one embodiment of this application, a light guide device is provided, see [link to relevant documentation]. Figure 3 and Figure 4 The light guide device includes a waveguide layer 1, a protective layer 2, and at least one multifunctional film layer 3. The waveguide layer 1 has a first surface 11 facing the protective layer 2, and a grating structure 13 is disposed on the first surface 11. The protective layer 2 is disposed opposite to and spaced apart from the waveguide layer 1. The at least one multifunctional film layer 3 is disposed between the waveguide layer 1 and the protective layer 2; wherein the multifunctional film layer 3 is disposed on the first surface of the waveguide layer 1 and / or the surface of the protective layer 2 facing the waveguide layer 1; the multifunctional film layer 3 includes a film layer A and a film layer B covering it, the film layer B and the film layer A satisfying a preset refractive index relationship to form an anti-reflection and anti-reflection structure on the surface of the light guide device.

[0031] This application relates to a diffractive waveguide device, designed to provide high-performance optical solutions for optical display devices such as AR smart glasses and HUDs. This device innovatively integrates at least one of the multifunctional film layers 3 between the waveguide layer 1 and the protective layer 2, solving a series of problems inherent in traditional waveguide architectures, such as high glare interference, insufficient image transmittance, and easy wear of the grating structure. Thus, while ensuring the device's thinness and lightness, it significantly improves the visual clarity and long-term durability of the final product.

[0032] The light guiding device provided in this application embodiment has an optical architecture mainly based on the synergistic combination of waveguide layer 1, protective layer 2, and at least one multifunctional film layer 3. The functions of each component and their synergistic working mechanism will be described in detail below.

[0033] The waveguide layer 1 serves as the main light-guiding component of the entire light-guiding device. (See also...) Figures 3 to 6The first surface 11 of the waveguide layer 1 integrates grating structures 13 with different functions. Based on the requirements of the light propagation path, these grating structures 13 can be divided into three functional regions: a coupling grating responsible for coupling external image light into the waveguide layer 1, a deflection grating controlling the direction of light propagation within the waveguide layer 1, and an output grating ultimately transmitting image information to the human eye's field of view. Through precise diffraction design, these grating structures 13 can efficiently couple image light emitted from an image source (such as an optical engine) into the waveguide layer 1, propagate it within the waveguide layer 1 via total internal reflection, and ultimately guide it precisely to the human eye, thereby achieving the fusion display of virtual images and real scenes.

[0034] It should be understood that the folding grating is an optional structure, and its configuration depends on the specific optical path design requirements.

[0035] The protective layer 2 is set opposite to the waveguide layer 1 by frame bonding. The protective layer 2 has two functions: firstly, it acts as a mechanical protective barrier to isolate foreign objects and prevent wiping, touching and other operations from directly damaging the underlying grating structure 13; secondly, it is made of a high light transmittance material to ensure that it provides physical protection without sacrificing any optical transmittance performance of the device.

[0036] The multifunctional film layer 3 is disposed on the first surface 11 of the waveguide layer 1 and / or the surface of the protective layer 2 facing the waveguide layer 1, and may include film layer A and film layer B covering it. By making film layer B and film layer A satisfy a specific refractive index relationship, a highly efficient anti-reflection and anti-reflection structure is constructed on the surface of the light guide device. The anti-reflection and anti-reflection structure can significantly improve the optical performance of the light guide device, specifically by effectively controlling the surface reflectivity to below 2% in the visible light band, for example, 450nm~700nm, while increasing the transmittance to above 98%, thereby greatly suppressing background glare and achieving excellent optical display effects.

[0037] See Figure 1 This demonstrates a traditional frame-mounted light guide device structure. This optical architecture has a significant drawback: see [link / reference needed] Figure 2 Multiple optical interfaces between waveguide layer 1 and protective layer 2 will cause significant Fresnel reflection, which not only causes overall transmittance loss, but also creates severe background glare behind the light guide device.

[0038] The light guide device provided in this application provides a systematic solution to the key technical defects of traditional waveguide architectures: (1) Solving the problem of low optical transmittance: In traditional architectures, the high refractive index difference interface between the waveguide layer, air gap, and protective layer will produce significant Fresnel reflection loss, resulting in insufficient energy of incident light. This application effectively reduces interface reflection and significantly improves the overall optical efficiency of the light guide device through an innovative anti-reflection and anti-reflection structure.

[0039] (2) Suppressing interface reflection glare: In traditional waveguide architectures, interface reflections in non-imaging optical path areas can generate strong background stray light and glare, which seriously interfere with the display of the main image information. The solution proposed in this application can effectively suppress such stray light and significantly improve the contrast, clarity and visual comfort of the displayed image.

[0040] In summary, the light guide device provided in this application, by setting the multifunctional film layer 3 on the corresponding surfaces of the waveguide layer 1 and / or the protective layer 2, wherein the multifunctional film layer 3 covers the film layer A through the film layer B in a stacked structure, and satisfies the optical relationship that the refractive index of the film layer B is less than that of the film layer A, constitutes a highly efficient anti-reflection and anti-reflection structure. This anti-reflection and anti-reflection structure effectively suppresses Fresnel reflections at multiple interfaces, including the waveguide layer surface, the protective layer surface, and the air gaps between them, by establishing an optimized refractive index gradient transition at key optical interfaces. This minimizes the light energy reflection loss originally caused by abrupt changes in refractive index, thereby significantly improving the overall optical transmittance of the device and eliminating background glare interference.

[0041] See some examples in this application. Figures 3 to 6 The film layer A is a dielectric film layer 31, the film layer B is an anti-fingerprint AF film layer 32, and the refractive index of the anti-fingerprint AF film layer 32 is less than the refractive index of the dielectric film layer 31 that is in direct contact with it.

[0042] In this example provided in this application, film layer A is specifically a dielectric film layer 31, and film layer B is specifically an anti-fingerprint AF film layer 32, wherein the refractive index of the anti-fingerprint AF film layer 32 is less than the refractive index of the dielectric film layer 31 in direct contact with it. Through this specific refractive index relationship design, the two film layers together constitute a highly efficient anti-reflection and anti-reflection structure, which can effectively control the surface reflectivity of the light guide device to below 2% in the visible light band (e.g., 450nm~700nm), while increasing the transmittance to over 98%, thereby significantly improving the problems of low transmittance and severe glare caused by interface reflection in traditional light guide architectures.

[0043] This design, based on the principle of optical interference, utilizes the stacked combination of dielectric film layer 31 and anti-fingerprint AF film layer 32 to form an optimized refractive index gradient, achieving a wide-band, high-efficiency anti-reflection effect. Furthermore, the anti-fingerprint AF film layer 32, while providing excellent optical performance, also offers surface protection: its material itself is resistant to fingerprint contamination and has an extremely low coefficient of friction. Even when in contact with the grating structure 13 during wiping, it effectively reduces friction, preventing damage to the grating and significantly improving the device's practicality and durability.

[0044] In some examples of this application, the refractive index of the anti-fingerprint AF film 32 is less than or equal to 1.4.

[0045] In the example provided in this application, the refractive index of the anti-fingerprint AF film 32 is optimized to be less than or equal to 1.4. This design, by employing a low-refractive-index anti-fingerprint AF film 32, creates a certain refractive index difference between it and the adjacent dielectric film 31, thereby establishing a more optimized refractive index gradient at the optical interface and enhancing the anti-reflection capability of the multifunctional film 3. This design significantly improves the transmittance in the visible light band and effectively suppresses reflection, providing key technical support for solving the problem of low optical efficiency in traditional waveguide architectures.

[0046] In a specific example of this application, the refractive index of the anti-fingerprint AF film layer 32 may be selected as 1.3. Those skilled in the art will understand that other values ​​that meet the requirements may also be used for the refractive index, such as 1.2, 1.35 or 1.4, all of which are within the protection scope of this application.

[0047] In some examples of this application, the multifunctional film layer 3 is configured such that the surface reflectivity of the light guide device is ≤2% and the transmittance is ≥98% in the visible light band.

[0048] Based on the excellent performance of the multifunctional film layer 3 in achieving a reflectivity of ≤2% and a transmittance of ≥98% in the visible light band, the embodiments of this application bring the following beneficial effects: By controlling reflectivity to an extremely low level and achieving high transmittance, the light extraction efficiency of the image source is significantly improved, resulting in a brighter and more energy-efficient display. Furthermore, it effectively suppresses background glare and stray light caused by interface reflections, significantly improving display contrast and visual comfort. This optical performance signifies a fundamental solution to the low transmittance and high glare problems caused by multi-interface Fresnel reflections between the waveguide layer and the protective layer in traditional waveguide architectures. Simultaneously, while achieving this optical breakthrough, this multifunctional film layer 3 has a compact structure that does not require alteration to the main waveguide architecture, providing crucial technical support for the thinning and high-performance of optical display devices.

[0049] See some examples in this application. Figures 3 to 6 The protective layer 2 has a support pillar layer on its surface facing the waveguide layer 1. The support pillar layer includes a plurality of discretely distributed micron-sized pillars 21. The multifunctional film layer 3 disposed on the protective layer 2 covers the support pillar layer and the adjacent area. The support pillar layer and the multifunctional film layer 3 covering it together form a rub-resistant structure to prevent damage caused by friction between the protective layer 2 and the grating structure 13 due to wiping and pressing.

[0050] The protective layer 2 is positioned opposite and spaced apart from the waveguide layer 1 via a frame-attach method. A support pillar layer is integrated on the surface of the protective layer 2 facing the waveguide layer 1. (See [reference]) Figures 3 to 6 The supporting pillar layer and the protective layer 2 together form a composite structure that combines protection and support functions. Through this composite structure design, the protective layer 2 not only provides basic physical protection for the light guide device, effectively isolating foreign objects and resisting daily contact, but more importantly, the supporting pillar layer on its surface can maintain a stable physical gap during wiping and pressing, thereby preventing the protective layer 2 from deforming as a whole and pressing against the grating structure 13 on the waveguide layer 1, fundamentally avoiding grating damage caused by contact friction.

[0051] The multifunctional film layer 3 is one of the core structures for achieving the abrasion resistance performance of this application. It is continuously applied to the protective layer 2 and the surface of the support pillar layer thereon. The outermost layer of the multifunctional film layer 3 is an anti-fingerprint AF film layer 32, which has a smooth surface and a low coefficient of friction, effectively dispersing and resisting frictional stress during the wiping process, thereby protecting the underlying grating structure 13. The anti-fingerprint AF film layer 32, covering the top of the micron-sized pillars 21, directly bears the wiping contact, and together with the support pillar layer, it constitutes a reliable abrasion-resistant structure. At the same time, the multifunctional film layer 3, through its optimized film system design, also has anti-reflection and anti-reflection functions, ensuring that the light guide device maintains excellent optical performance while providing mechanical protection. Through the above integrated design, this application achieves an organic combination of mechanical protection and optical performance, significantly improving the practicality and long-term reliability of the light guide device.

[0052] In some examples of this application, the refractive index n of the micrometer-scale pillar 21 p The refractive index n of the protective layer 2 cover Satisfying the relation: |n p –n cover |≤0.3.

[0053] In this application, both the protective layer 2 and the supporting column layer are made of high-transmittance materials and meet the refractive index matching requirement, i.e., |n p –n cover|≤0.3. This optical parameter design ensures the continuity of optical performance as light passes through the composite structure, enabling the light guide device to maintain excellent imaging quality while achieving mechanical protection.

[0054] In this example design of the application, the refractive index n of the micrometer-scale column 21 is... p The refractive index n of the protective layer 2 cover To satisfy |n p –n cover The optical parameter design, based on the relationship of |≤0.3, is grounded in optical matching considerations. By controlling the refractive index of the support pillar layer to be close to that of the protective layer 2, the reflection and scattering effects of light at the interface between the protective layer and the support pillar can be reduced. If the refractive index difference between the two is too large, significant Fresnel reflection and light scattering will occur at each micron-level pillar interface. These stray lights will interfere with the normal imaging optical path, leading to problems such as decreased contrast and background glare in the light guide device. This application, through the above-mentioned refractive index matching design, maximizes the purity and optical efficiency of the optical path while introducing a mechanical support structure, ensuring high imaging quality of the light guide device.

[0055] In some examples of this application, the cross-sectional diameter of the micron-sized column 21 is less than 2 μm and its height is less than 20 μm.

[0056] In the example provided in this application, the micron-sized pillars 21 in the support pillar layer are designed with a diameter of less than 2 μm and a height of less than 20 μm. This size parameter can establish a stable and small physical gap between the waveguide layer 1 and the protective layer 2, which not only ensures that the two layers can remain effectively separated during wiping to avoid direct contact damage, but also minimizes the interference of the support structure on light propagation.

[0057] In this application, the refractive index n of the micron-sized column 21 is... p The refractive index n of the protective layer 2 cover Need to satisfy |n p –n cover The matching requirement of |≤0.3 is designed to make the optical properties at the interface between the support column layer and the protective layer more consistent, effectively eliminating stray light and interface reflection caused by abrupt changes in refractive index.

[0058] Through comprehensive optimization of the above-mentioned structural dimensions and optical parameters, this application achieves reliable mechanical protection while fully ensuring the excellent optical performance of the light guide device.

[0059] In some examples of this application, the dielectric film layer 31 is a single-layer structure, and its refractive index is less than that of the substrate to which it is attached, the substrate being the grating structure 13 or the protective layer 2.

[0060] In this example provided in this application, the dielectric film layer 31 adopts a single-layer structure design, and its refractive index is configured to be lower than that of the substrate to which it is attached (i.e., the grating structure 13 or the protective layer 2). This design effectively mitigates Fresnel reflections that would normally occur at the substrate-air interface due to a sharp change in refractive index by establishing an optimized refractive index transition between the single-layer dielectric film layer 31 and the substrate. Even under simplified structural conditions, this design can still significantly improve the optical transmittance of the light guide device and effectively suppress background glare, achieving a good anti-reflection and anti-reflection effect.

[0061] Furthermore, the single-layer dielectric film 31 not only significantly simplifies the coating process, improves manufacturing efficiency, and reduces industrialization costs, but also helps maintain the thin and light characteristics of the light guide device. This single-layer dielectric film 31, combined with the lower refractive index anti-fingerprint AF film 32, can construct a composite film structure with a smooth refractive index gradient and excellent optical performance, ensuring both optical performance and process feasibility and economy.

[0062] See a specific example in this application. Figure 4 The light guiding device has the multifunctional film layer 3 disposed on the opposing surfaces of the protective layer 2 and the waveguide layer 1. Specifically, in the multifunctional film layer 3 disposed on the protective layer 2, its dielectric film layer 31 adopts a single-layer structure, and the refractive index of the dielectric film layer 31 is set to be both less than the refractive index of the protective layer 2 to which it is attached and greater than the refractive index of the anti-fingerprint AF film layer 32 directly covering its surface.

[0063] See a specific example in this application. Figure 5 and Figure 6 The light guiding device has the multifunctional film layer 3 disposed on the opposing surfaces of the waveguide layer 1 and the protective layer 2. Specifically, in the multifunctional film layer 3 disposed on the first surface 11 of the waveguide layer 1, the dielectric film layer 31 adopts a single-layer structure. The refractive index of the dielectric film layer 31 is set to be both less than the refractive index of the grating structure 13 of the waveguide layer 1 to which it is attached and greater than the refractive index of the anti-fingerprint AF film layer 32 directly covering its surface. Correspondingly, in the multifunctional film layer 3 disposed on the surface of the protective layer 2 facing the waveguide layer 1, the dielectric film layer 31 also adopts a single-layer structure. The refractive index of the dielectric film layer 31 is set to be both less than the refractive index of the protective layer 2 to which it is attached and greater than the refractive index of the anti-fingerprint AF film layer 32 directly covering its surface.

[0064] See Figure 5 and Figure 6Through this symmetrical film design with refractive index gradient characteristics, a complete refractive index transition structure is formed at the optical interface between the waveguide layer 1 and the protective layer, which not only significantly improves the anti-reflection and anti-reflection effect, but also maintains the simplicity of the structure and the feasibility of the process.

[0065] For a specific example in this application, please refer to [link / reference]. Figure 5 and Figure 6 Each of the multifunctional film layers 3 is composed of a dielectric film layer 31 with a refractive index of 1.5 and an anti-fingerprint AF film layer 32 with a refractive index of 1.3, stacked sequentially. Through the optimized design of this dual-layer film structure, optical performance of reflectivity <4.3% and transmittance >95.7% can be achieved in the visible light band, such as 450mm~700nm, which is a significant improvement over the traditional structure.

[0066] It should be noted that the structure of the multifunctional film layer 3 can be simplified according to actual needs. In another embodiment, see... Figure 3 The multifunctional film layer 3 can also consist of only one anti-fingerprint AF film layer 32. For example, when the multifunctional film layer 3 consists of only a single anti-fingerprint AF film layer 32 with a refractive index of 1.3, this simplified structure can achieve optical improvement effects of reflectivity <6% and transmittance >94% in the visible light band, providing flexible options for application scenarios with different performance requirements.

[0067] In some examples of this application, the dielectric film layer 31 is a multilayer structure, which includes at least one high refractive index layer and at least one low refractive index layer alternately stacked, and the difference in refractive index between the high refractive index layer and the low refractive index layer is not less than 0.3; wherein, the refractive index of the low refractive index layer is less than the refractive index of the substrate to which it is attached, and the substrate is the grating structure 13 or the protective layer 2.

[0068] In this example provided in this application, the dielectric film layer 31 employs a more complex multilayer structure design, consisting of alternating layers of at least one high-refractive-index layer and at least one low-refractive-index layer, wherein the refractive index difference between the high- and low-refractive-index layers is controlled within a range of not less than 0.3. This design significantly enhances the optical interference effect within the film system by establishing sufficient refractive index contrast, thereby achieving superior antireflection performance in the visible light band.

[0069] The multilayer structure design in this example offers several technical advantages: First, based on the optical interference effect of the multilayer film system, it can maintain stable low reflectivity characteristics over a wider wavelength range and incident angle, keeping the reflectivity of the light guide device stable below 2%; second, by establishing an optimized refractive index gradient transition, reflection fluctuations at different wavelengths and incident angles are effectively suppressed, ensuring the consistency of optical performance; in addition, the multilayer structure design provides greater controllability, allowing for precise control of the number, thickness, and material combination of the dielectric film 31 to meet specific optical performance requirements.

[0070] In a specific example of this application, the multifunctional film layer 3 employs a four-layer alternating stacked structure as the dielectric film layer 31, and is covered with an anti-fingerprint AF film layer 32 on the outermost layer. The low refractive index layer (refractive index 1.5) and the high refractive index layer (refractive index 2.0) are arranged alternately with a refractive index difference of 0.5. This film structure achieves excellent optical performance in the visible light band (e.g., 450nm~700nm) with a reflectivity of <4% and a transmittance of >96%, balancing the anti-reflection effect with the fabrication complexity.

[0071] In another specific example of this application, the multifunctional film layer 3 employs a six-layer alternating stacked structure as the dielectric film layer 31, and is covered with an anti-fingerprint AF film layer 32 on the outermost layer. The low refractive index layer (refractive index 1.5) and the high refractive index layer (refractive index 2.0) are arranged alternately with a refractive index difference of 0.5. This film structure utilizes the significant refractive index difference to enhance the optical interference effect, achieving excellent optical performance of reflectivity <2% and transmittance >98% in the visible light band (e.g., 450nm~700nm), providing crucial optical assurance for high-performance applications such as AR displays.

[0072] It should be noted that to achieve a wider operating bandwidth, a multi-layered dielectric film structure can be used. With the increase in the number of dielectric film layers, the optical interference effect is further enhanced, effectively broadening the response bandwidth of the light guide device in terms of wavelength and angle, providing reliable optical protection for high-performance applications such as AR displays. At the same time, through reasonable structural design, even with a multi-layered film system, the light guide device can maintain its thin and light characteristics, achieving a balance between optical performance and practicality.

[0073] In some examples of this application, the dielectric film layers 31 of the multilayer structure disposed on the waveguide layer 1 are arranged in the order of low refractive index layer first and high refractive index layer outward from the grating structure 13; the dielectric film layers 31 disposed on the protective layer 2 are arranged in the order of high refractive index layer first and low refractive index layer outward from the protective layer 2.

[0074] In this example of the application, differentiated multilayer dielectric film stacking sequence designs were adopted for the different optical substrate characteristics of the waveguide layer 1 and the protective layer 2, resulting in more optimized optical performance: For the multilayer dielectric film layer 31 disposed on the waveguide layer 1, it is stacked outward from the grating structure 13 in the order of low refractive index layer first and then high refractive index layer. This design fully considers the characteristic that the grating structure 13 usually has a high refractive index. By stacking from the low refractive index, the abrupt change in refractive index between the high refractive index grating substrate and the film layer is effectively mitigated, and a smoother optical transition is established.

[0075] For the multilayer dielectric film layer 31 disposed on the protective layer 2, it is stacked outward from the protective layer 2 and the support pillar layer in the order of high refractive index layer followed by low refractive index layer. This design better matches the relatively low refractive index characteristics of the protective layer 2, and achieves optimal optical matching from the protective layer to the film system by stacking from the high refractive index.

[0076] This differentiated stacking sequence design is based on the strict principle of optical impedance matching, constructing optimal refractive index transition paths for substrates with different refractive index characteristics, thereby maximizing the anti-reflection effect. Through this designed film structure, the multifunctional film layer 3 disposed on the waveguide layer 1 and the protective layer 2 can work together to construct a complete optical optimization system, achieving unified high performance in a multilayer optical structure and significantly improving the optical efficiency of the light guide device.

[0077] In a specific example of this application, the light guiding device has a multifunctional film layer 3 disposed on the first surface 11 of the waveguide layer 1 and the surface of the protective layer 2 facing the waveguide layer. The multifunctional film layer 3 located on the surface of the waveguide layer 1 adopts a six-layer alternating stacked structure as the dielectric film layer 31, and its stacking order from the grating structure 13 outward is as follows: low refractive index layer (1.5), high refractive index layer (2.0), low refractive index layer, high refractive index layer, low refractive index layer, high refractive index layer, and the outermost layer is covered with an anti-fingerprint AF film layer 32, forming a low-high-low-high-low-high-AF film system structure.

[0078] Correspondingly, the multifunctional film layer 3 located on the surface of the protective layer 2 also adopts a six-layer alternating stacked structure, but its stacking order from the protective layer 2 outward is as follows: high refractive index layer (2.0), low refractive index layer (1.5), high refractive index layer, low refractive index layer, high refractive index layer, low refractive index layer, and the outermost layer is covered with an anti-fingerprint AF film layer 32, forming a high-low-high-low-high-low-AF film system structure.

[0079] This symmetrical design with reversed stacking order achieves optimal anti-reflection performance by establishing optimal refractive index transition paths at two key optical interfaces, while maximizing the overall optical system performance.

[0080] See Figures 7 to 10 The paper showcases the optical performance of traditional light guide devices. Figure 7 and Figure 8 The reflectivity and transmittance distribution characteristics of the device under different incident angles are presented respectively. Figure 9 and Figure 10 This reflects the reflectance and transmittance spectral curves when incident in the visible light band. Test data shows that for traditional architectures using a grating structure with a refractive index of 1.7 and a waveguide layer with a refractive index of 1.5, without any multifunctional films, their optical performance has significant limitations: such as... Figures 7 to 10 As shown, the reflectivity remains above 7.5% throughout the entire operating band, while the corresponding transmittance is below 92.5%.

[0081] See Figures 11 to 14 The optical performance of the light guide device provided by the specific example above (i.e., the dielectric film layer 31 in both waveguide layer 1 and protective layer 2 is a six-layer alternating stacked structure) is shown. Figure 11 and Figure 12 The reflectivity and transmittance distribution characteristics of the light guide device of this application under different incident angles are presented respectively. Figure 13 and Figure 14 This reflects the reflectance and transmittance spectral curves when incident in the visible light band. Test results show that: Figure 11 and Figure 13 As shown, the reflectivity of the light guide device in this application is consistently controlled below 2% across the entire operating wavelength range and at different incident angles; simultaneously, as Figure 12 and Figure 13 As shown, the transmittance under the corresponding conditions remains above 98%. This data verifies that by introducing a multifunctional film structure, this application reduces the device reflectivity from >7.5% to ≤2% of the traditional structure and increases the transmittance from <92.5% to ≥98%, achieving a breakthrough improvement in optical performance.

[0082] It should be noted that the light guiding device described in this application can adopt a dual-sided configuration scheme in which multifunctional film layers 3 are respectively set on the protective layer 2 and the waveguide layer 1. This design achieves optical optimization effects that are difficult to achieve with a single film layer through the synergistic effect of the two film layers. Specifically, by simultaneously setting the multifunctional film layer 3 on the first surface 11 of the waveguide layer 1 and the inner surface of the protective layer 2, a complete optical interface optimization system is constructed, which can systematically eliminate multiple interface reflections in the waveguide-protective layer gap from the structural level.

[0083] Compared to solutions with functional layers on only one side, this dual-sided collaborative configuration exhibits significant advantages in the following aspects: First, it can more thoroughly suppress Fresnel reflections at various optical interfaces, minimizing reflectivity across the entire range; second, through the coordinated design of the two film systems, a more complete optical impedance transition can be established, ensuring that the transmission efficiency of light in the waveguide layer 1-protective layer 2 combined structure is maximized. This innovative design fundamentally solves the problems of insufficient transmittance and glare caused by interface reflections in traditional architectures, providing a reliable solution for high-performance optical display devices.

[0084] In some examples of this application, the anti-fingerprint AF film 32 comprises at least one of a fluoropolymer, a siloxane polymer, or a nano-silica composite.

[0085] The selection of these specific materials has dual technical advantages: First, their inherent low surface energy characteristics provide the film with durable anti-fingerprint and anti-fouling capabilities; at the same time, the low refractive index characteristics of these materials (typically ≤1.4) enable them to form an ideal refractive index match with the dielectric film 31, jointly constructing an efficient anti-reflection structure, achieving surface protection while ensuring excellent optical performance.

[0086] See some examples in this application. Figure 5 and Figure 6 The surface morphology of the multifunctional film layer 3 on the waveguide layer 1 is conformal to or planar with the grating structure 13; the multifunctional film layer 3 on the protective layer 2 covers the support column layer and forms a plane.

[0087] In the example provided in this application, the multifunctional film layer 3 on the waveguide layer 1 can adopt two different surface morphologies according to process requirements: conformal coverage with the grating structure 13, or forming a flat surface. Conformal coverage can maintain the integrity of the original grating contour and ensure the consistency of optical performance; while planarization can significantly simplify subsequent process steps, reduce fabrication difficulty and production cost, and provide flexible process options for different application scenarios.

[0088] Meanwhile, the multifunctional film layer 3 on the protective layer 2 completely covers the support pillar layer and adjacent areas, creating a stable spacing structure between the waveguide layer 1 and the protective layer 2. This planar design not only ensures the consistency of the optical interface and reduces light scattering caused by surface undulations, but also provides a uniform force-bearing plane for the wiping process, further enhancing the device's wiping resistance and optical stability.

[0089] In summary, the light guide device provided in this application systematically solves the three core problems of traditional waveguide architecture: improving light energy utilization, optimizing image quality, and enhancing mechanical durability, thus providing a reliable technical guarantee for realizing high-performance optical displays.

[0090] According to another embodiment of this application, an optical display device is provided, the optical display device including an image source and a light guide device as described in the first aspect, wherein the image source is configured to provide image light, and the light guide device is configured to receive and conduct the image light provided by the image source and couple the image light into the user's field of view.

[0091] The specific implementation of the optical display device in this application can refer to the various embodiments of the light guide device described above. Therefore, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0092] 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.

[0093] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A light guide device, characterized in that, include: The waveguide layer (1) has a first surface (11) facing the protective layer (2), and a grating structure (13) is provided on the first surface (11). A protective layer (2) is disposed opposite to and spaced apart from the waveguide layer (1); and, At least one multifunctional film layer (3) is disposed between the waveguide layer (1) and the protective layer (2); The multifunctional film layer (3) is disposed on the first surface of the waveguide layer (1), and / or the protective layer (2) is disposed on the surface of the waveguide layer (1); The multifunctional film layer (3) includes film layer A and film layer B covering it. Film layer B and film layer A satisfy a preset refractive index relationship to form an anti-reflection and anti-reflection structure on the surface of the light guide device.

2. The light guide device according to claim 1, characterized in that, The film layer A is a dielectric film layer (31), the film layer B is an anti-fingerprint AF film layer (32), and the refractive index of the anti-fingerprint AF film layer (32) is less than the refractive index of the dielectric film layer (31) that is in direct contact with it.

3. The light guide device according to claim 2, characterized in that, The refractive index of the anti-fingerprint AF film (32) is less than or equal to 1.

4.

4. The light guide device according to claim 2, characterized in that, The multifunctional film layer (3) is configured such that the surface reflectivity of the light guide device is ≤2% and the transmittance is ≥98% in the visible light band.

5. The light guide device according to any one of claims 2-4, characterized in that, The protective layer (2) has a support pillar layer on the surface facing the waveguide layer (1), and the support pillar layer includes a plurality of discretely distributed micron-sized pillars (21). The multifunctional film layer (3) disposed on the protective layer (2) covers the support column layer and the adjacent area. The support column layer and the multifunctional film layer (3) covering it together form a rub-resistant structure to prevent damage caused by friction between the protective layer (2) and the grating structure (13) due to wiping and pressing.

6. The light guide device according to claim 5, characterized in that, The refractive index n of the micron-sized column (21) p The refractive index n of the protective layer (2) cover Satisfying the relation: |n p –n cover |≤0.

3.

7. The light guide device according to claim 5, characterized in that, The cross-sectional diameter of the micron-sized column (21) is less than 2 μm and its height is less than 20 μm.

8. The light guide device according to claim 5, characterized in that, The dielectric film layer (31) is a single-layer structure, and its refractive index is less than that of the substrate to which it is attached. The substrate is the grating structure (13) or the protective layer (2).

9. The light guide device according to claim 5, characterized in that, The dielectric film layer (31) is a multilayer structure, which includes at least one high refractive index layer and at least one low refractive index layer alternately stacked, and the difference in refractive index between the high refractive index layer and the low refractive index layer is not less than 0.

3. Wherein, the refractive index of the low refractive index layer is less than the refractive index of the substrate to which it is attached, and the substrate is the grating structure (13) or the protective layer (2).

10. The light guide device according to claim 9, characterized in that, The dielectric film layer (31) of the multilayer structure disposed on the waveguide layer (1) is arranged in the order of low refractive index layer followed by high refractive index layer from the grating structure (13) outward; The dielectric film layer (31) disposed on the protective layer (2) is arranged in the order of high refractive index layer first and low refractive index layer from the protective layer (2) outward.

11. The light guide device according to claim 2, characterized in that, The anti-fingerprint AF film (32) comprises at least one of a fluoropolymer, a siloxane polymer, or a nano silica composite.

12. The light guide device according to claim 1, characterized in that, The surface morphology of the multifunctional film layer (3) on the waveguide layer (1) is conformal to or planar with the grating structure (13); The multifunctional membrane layer (3) on the protective layer (2) covers the support column layer and forms a plane.

13. An optical display device, characterized in that, include: The image source is configured to provide image light; as well as, The light guide device as claimed in any one of claims 1 to 12 is configured to receive and conduct the image light provided by the image source and couple the image light into the user's field of view.

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