Optical waveguide structure and manufacturing method therefor, and head-mounted display device

Abstract

An optical waveguide structure and a manufacturing method therefor, and a head-mounted display device. The optical waveguide structure comprises: an optical waveguide substrate. The optical waveguide substrate comprises a grating region, and a grating structure in the grating region is composed of a cured imprint adhesive; and a non-grating region on the optical waveguide substrate other than the grating region is a glare suppression region, and the optical waveguide substrate in the glare suppression region is configured such that: a. there is no imprint adhesive on the surface, or b. there is an imprint adhesive on the surface, and a first glare suppression layer is further arranged on at least part of the imprint adhesive, the first glare suppression layer being used for reducing the reflectivity of the non-grating region of the optical waveguide structure.

Description

Optical waveguide structure and its fabrication method and head-mounted display device

[0001] This application claims priority to Chinese Patent Application No. 202411996681.1, filed with the Chinese Patent Office on December 31, 2024, entitled "Optical Waveguide Structure and Preparation Method Thereof and Head-Mounted Display Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optical waveguide technology, and in particular to an optical waveguide structure, its fabrication method, and a head-mounted display device. Background Technology

[0003] With the rapid development of Augmented Reality (AR) technology, diffractive waveguides, as core optical display devices in the AR field, play a crucial role. By precisely controlling the propagation path of light, diffractive waveguides enable the aerial projection of image information and the superposition of virtual images, providing users with an immersive visual experience.

[0004] In the manufacturing process of diffractive waveguides, nanoimprint lithography is widely used due to its high precision and efficiency. During nanoimprint lithography, to enhance the diffraction effect of the grating and improve the overall efficiency of the waveguide, an imprinting adhesive with a refractive index higher than the substrate material is typically chosen as the material constituting the grating. This leads to a significant increase in the surface reflectivity of the non-grating areas. However, during the use of AR devices, when external light shines on the non-grating areas, strong reflection occurs, resulting in a glare effect. In other words, the existing waveguide structure causes a glare effect during use.

[0005] The above content is only used to help understand the technical solution of this application and does not represent an admission that the above content is prior art. Summary of the Invention

[0006] The main objective of this application is to provide an optical waveguide structure, its fabrication method, and a head-mounted display device, aiming to solve the technical problem of glare effect caused by existing optical waveguide structures during use.

[0007] To achieve the above objectives, this application proposes an optical waveguide structure, which includes: an optical waveguide substrate;

[0008] The optical waveguide substrate includes a grating region, and the grating structure within the grating region is composed of cured imprinted adhesive;

[0009] The non-grating region on the optical waveguide substrate, excluding the grating region, is a glare suppression region. The optical waveguide substrate within the glare suppression region is configured as follows:

[0010] a. No embossing adhesive on the surface, or

[0011] b. The surface has an imprinting adhesive, and at least a portion of the imprinting adhesive is further provided with a first glare suppression layer, the first glare suppression layer being used to reduce the reflectivity of the non-grating region of the optical waveguide structure.

[0012] In one embodiment, when there is no imprinted adhesive on the surface of the optical waveguide substrate, the glare suppression region further includes a second glare suppression layer disposed on at least a portion of the optical waveguide substrate.

[0013] In one embodiment, the second glare suppression layer includes a second anti-reflection film layer on the optical waveguide substrate, wherein the refractive index of the second anti-reflection film layer is less than the refractive index of the optical waveguide substrate; or,

[0014] The second glare suppression layer includes at least two second anti-reflection film layers on the optical waveguide substrate, wherein the refractive index of the second anti-reflection film layer farthest from the optical waveguide substrate is less than or equal to the refractive index of the optical waveguide substrate.

[0015] In one embodiment, the thickness of the second antireflective coating is determined based on the geometry and refractive index of the optical waveguide substrate and the refractive index of the second antireflective coating.

[0016] In one embodiment, when an imprinted adhesive is present on the surface of the optical waveguide substrate within the glare suppression region, the first glare suppression layer includes a first antireflective film layer on the optical waveguide substrate, wherein the refractive index of the first antireflective film layer is less than the refractive index of the imprinted adhesive; or,

[0017] The first glare suppression layer includes at least two first antireflective film layers on the imprinting adhesive, wherein the refractive index of the first antireflective film layer furthest from the imprinting adhesive is less than or equal to the refractive index of the imprinting adhesive.

[0018] In one embodiment, the thickness of the first antireflective film is determined based on the geometry and refractive index of the optical waveguide substrate, the thickness and refractive index of the adhesive layer in the glare suppression region, and the refractive index of the first antireflective film.

[0019] Furthermore, to achieve the above objectives, this application also proposes a method for fabricating an optical waveguide structure, the method comprising:

[0020] Partitioning and homogenizing the grating region of the optical waveguide substrate with imprinted adhesive;

[0021] A master template for grating structure imprinting is provided. The master template for grating structure imprinting is used to imprint the imprinting adhesive on the optical waveguide substrate to form a grating structure within the grating region of the optical waveguide substrate.

[0022] The imprinted adhesive is cured, and the master template of the grating structure is demolded from the imprinted adhesive to obtain the optical waveguide structure.

[0023] In one embodiment, after the steps of curing the imprinted adhesive and demolding the master template of the grating structure imprint from the imprinted adhesive, the method includes:

[0024] A second glare suppression layer is deposited on the non-grating region of the optical waveguide substrate, excluding the grating region, wherein the second glare suppression layer is used to reduce the reflectivity of the non-grating region of the optical waveguide structure.

[0025] In one embodiment, the second glare suppression layer includes a second anti-reflection film layer on the optical waveguide substrate, wherein the refractive index of the second anti-reflection film layer is less than the refractive index of the optical waveguide substrate;

[0026] Alternatively, the second glare suppression layer includes at least two second anti-reflective film layers on the optical waveguide substrate, wherein the refractive index of the second anti-reflective film layer furthest from the optical waveguide substrate is less than or equal to the refractive index of the optical waveguide substrate.

[0027] In one embodiment, prior to the step of depositing a second glare suppression layer on the non-grating region of the optical waveguide substrate other than the grating region, the method includes:

[0028] Obtain the geometry and refractive index of the optical waveguide substrate;

[0029] Based on the geometry and refractive index of the optical waveguide substrate and the refractive index of the second antireflection film, a simulation model of the optical waveguide structure is constructed.

[0030] Based on the simulation model of the optical waveguide structure, the first optional thickness of the second antireflection film is simulated to obtain the theoretical reflectivity of the optical waveguide structure corresponding to the first optional thickness;

[0031] Based on the theoretical reflectivity, the thickness of the second antireflective film is selected from the first selectable thicknesses.

[0032] Furthermore, to achieve the above objectives, this application also proposes a method for fabricating an optical waveguide structure, the method comprising:

[0033] Spin coating and homogenization of imprinting adhesive onto an optical waveguide substrate;

[0034] A master template for grating structure imprinting is provided. The master template for grating structure imprinting is used to imprint the imprinting adhesive on the optical waveguide substrate to form a grating structure within the grating region of the optical waveguide substrate.

[0035] The embossing adhesive is cured after embossing, and the master template of the grating structure embossing is demolded from the embossing adhesive;

[0036] A first glare suppression layer is deposited on the non-grating region (excluding the grating region) of the optical waveguide substrate to obtain an optical waveguide structure, wherein the first glare suppression layer is used to reduce the reflectivity of the non-grating region of the optical waveguide structure.

[0037] In one embodiment, the first glare suppression layer includes a first anti-reflection film layer on the optical waveguide substrate, wherein the refractive index of the first anti-reflection film layer is less than the refractive index of the imprinting adhesive;

[0038] Alternatively, the first glare suppression layer includes at least two first antireflective film layers on the imprinting adhesive, wherein the refractive index of the first antireflective film layer furthest from the imprinting adhesive is less than or equal to the refractive index of the imprinting adhesive.

[0039] In one embodiment, prior to the step of depositing a first glare suppression layer on the non-grating region of the optical waveguide substrate other than the grating region, the method includes:

[0040] Obtain the geometry and refractive index of the optical waveguide substrate, as well as the thickness and refractive index of the imprinted adhesive layer in the non-grating region;

[0041] Based on the geometry and refractive index of the optical waveguide substrate, the thickness and refractive index of the imprinted adhesive layer, and the refractive index of the first antireflective film layer, a simulation model of the optical waveguide structure is constructed.

[0042] Based on the simulation model of the optical waveguide structure, the second optional thickness of the first anti-reflection film is simulated to obtain the theoretical reflectivity of the optical waveguide structure corresponding to the second optional thickness;

[0043] The thickness of the first antireflective film is selected from the second selectable thicknesses based on the theoretical reflectivity.

[0044] In addition, to achieve the above objectives, this application also proposes a head-mounted display device, which includes the optical waveguide structure described above.

[0045] One or more technical solutions proposed in this application have at least the following technical effects:

[0046] In this application, the optical waveguide structure includes: an optical waveguide substrate; a grating region on the optical waveguide substrate, wherein the grating structure within the grating region is composed of cured imprinted adhesive; and a non-grating region on the optical waveguide substrate other than the grating region, which is a glare suppression region. The optical waveguide substrate within the glare suppression region is configured such that: a. there is no imprinted adhesive on the surface, or b. there is imprinted adhesive on the surface, and at least a portion of the imprinted adhesive is further provided with a first glare suppression layer. This first glare suppression layer is used to reduce the reflectivity of the non-grating region of the optical waveguide structure. Therefore, this application, by treating the non-grating region on the optical waveguide substrate (excluding the grating region) with either no imprinted adhesive or by adding a first glare suppression layer, reduces the glare effect when external light shines on the non-grating region during the use of AR devices, thus suppressing the glare effect present in existing optical waveguide structures. Attached Figure Description

[0047] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0048] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 is a schematic diagram of the optical waveguide structure;

[0050] Figure 2 is a schematic diagram of an existing optical waveguide structure;

[0051] Figure 3 is a schematic diagram of the glare effect of existing optical waveguide structures;

[0052] Figure 4 is a schematic diagram of an optical waveguide structure provided in an embodiment of this application;

[0053] Figure 5 is a schematic diagram of a common existing original optical waveguide structure;

[0054] Figure 6 is a schematic diagram of the reflectivity results of the original optical waveguide structure;

[0055] Figure 7 is a schematic diagram of the reflectivity results of an optical waveguide structure provided in an embodiment of this application;

[0056] Figure 8 is a schematic diagram of another optical waveguide structure provided in an embodiment of this application;

[0057] Figure 9 is a schematic diagram of another optical waveguide structure provided in an embodiment of this application;

[0058] Figure 10 is a schematic diagram showing the relationship between the optional thickness of the single-layer second antireflective film layer and the theoretical reflectivity in the embodiments of this application;

[0059] Figure 11 is a schematic diagram showing the relationship between the optional thickness of the double-layer second antireflective film layer and the theoretical reflectivity in an embodiment of this application;

[0060] Figure 12 is a schematic diagram of another optical waveguide structure provided in an embodiment of this application;

[0061] Figure 13 is a schematic diagram of another optical waveguide structure provided in an embodiment of this application;

[0062] Figure 14 is a schematic diagram of the reflectivity results of another optical waveguide structure provided in an embodiment of this application;

[0063] Figure 15 is a schematic diagram of the reflectivity results of another optical waveguide structure provided in the embodiment of this application;

[0064] Figure 16 is a schematic diagram of another optical waveguide structure provided in an embodiment of this application;

[0065] Figure 17 is a schematic diagram of the reflectivity results of another optical waveguide structure provided in the embodiment of this application;

[0066] Figure 18 is a schematic flowchart of the first embodiment of the fabrication method of the optical waveguide structure of this application;

[0067] Figure 19 is a fabrication scenario diagram involving an embodiment of the fabrication method of the optical waveguide structure of this application;

[0068] Figure 20 is a fabrication scenario diagram involving another embodiment of the fabrication method of the optical waveguide structure of this application;

[0069] Figure 21 is a fabrication scenario diagram involving another embodiment of the fabrication method of the optical waveguide structure of this application;

[0070] Figure 22 is a schematic flowchart of the second embodiment of the fabrication method of the optical waveguide structure of this application;

[0071] Figure 23 is a fabrication scenario diagram involving another embodiment of the fabrication method of the optical waveguide structure of this application;

[0072] Figure 24 is a fabrication scenario diagram involving another embodiment of the fabrication method of the optical waveguide structure of this application;

[0073] Figure 25 is a fabrication scenario diagram involving another embodiment of the fabrication method of the optical waveguide structure of this application;

[0074] Figure 26 is a schematic diagram of the scenario in which the process parameters of the preparation method involved in the embodiments of this application are determined.

[0075] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0076] Embodiments of this disclosure will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this disclosure, and should not be construed as limiting this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

[0077] The terms "first" and "second" in this disclosure may explicitly or implicitly include one or more of the features. In the description of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0078] In the description of this disclosure, it should be understood that the terms "center," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0079] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure based on the specific circumstances.

[0080] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0081] The main solution of this application embodiment is: the optical waveguide substrate includes a grating region, and the grating structure within the grating region is composed of cured imprinting adhesive; the non-grating region on the optical waveguide substrate other than the grating region is a glare suppression region, and the glare suppression region includes an optical waveguide substrate without imprinting adhesive on its surface, or the optical waveguide substrate included in the glare suppression region is configured as: a. without imprinting adhesive on its surface, or b. with imprinting adhesive on its surface, and at least a portion of the imprinting adhesive is further provided with a first glare suppression layer, the first glare suppression layer being used to reduce the reflectivity of the non-grating region of the optical waveguide structure.

[0082] Nanoimprint lithography is widely used in the fabrication of diffractive waveguides due to its high precision and efficiency. Figure 1 shows a schematic diagram of the waveguide structure involved in this application. Depending on the design architecture, diffractive waveguides are mainly divided into two categories: one-dimensional (1D) structures and two-dimensional (2D) structures. Although they differ in construction and application scenarios, they share the common feature of containing grating and non-grating regions on their surface. The grating region is the key part of the diffractive waveguide for achieving light diffraction and guidance. Through specific micro / nano structure design, light is diffracted at a specific angle inside the waveguide and then guided to the user's eye. In contrast, the non-grating region mainly serves to support and protect the grating structure and maintain the overall structural integrity of the waveguide.

[0083] As shown in Figure 2, during the nanoimprinting process, to enhance the diffraction effect of the grating and improve the overall efficiency of the waveguide, an imprinting adhesive with a refractive index higher than that of the substrate material is typically chosen as the material constituting the grating. This leads to a significant increase in the surface reflectivity of the non-grating area. However, as shown in Figure 3, during the use of AR devices, when external light shines on the non-grating area, strong reflection occurs, resulting in a glare effect. In other words, the existing optical waveguide structure causes a glare effect during use.

[0084] This application provides a solution that reduces glare on non-grating areas (excluding the grating region) of the optical waveguide substrate by either removing the surface adhesive or adding a first glare suppression layer. This reduces the glare effect when external light shines on the non-grating areas during AR device use, thus suppressing the glare effect present in existing optical waveguide structures.

[0085] Based on this, as shown in Figure 4, this application provides an optical waveguide structure, which includes an optical waveguide substrate;

[0086] The optical waveguide substrate includes a grating region, and the grating structure within the grating region is composed of cured imprinted adhesive;

[0087] The non-grating region on the optical waveguide substrate, excluding the grating region, is a glare suppression region. The optical waveguide substrate within the glare suppression region is configured such that: a. there is no imprinted adhesive on the surface, or b. there is imprinted adhesive on the surface, and at least a portion of the imprinted adhesive is further provided with a first glare suppression layer. The first glare suppression layer is used to reduce the reflectivity of the non-grating region of the optical waveguide structure.

[0088] In this embodiment, the optical waveguide substrate is a matrix of an optical waveguide structure made of inorganic or polymeric transparent materials, such as silica, fused silica, borosilicate glass, polymethyl methacrylate, polystyrene, polycarbonate, poly(4-methylpentene-1), styrene-acrylonitrile copolymer, allyl diethylene glycol dicarbonate, etc. The grating structure within the grating region is composed of a cured imprinting adhesive with a specific structure, used to achieve light diffraction and guidance. The non-grating region refers to the area on the optical waveguide substrate other than the grating region. The imprinting adhesive is a thermosensitive or photosensitive cured adhesive with good light transmittance used in nanoimprinting processes.

[0089] In nanoimprinting, to enhance the diffraction effect of the grating structure and improve the overall efficiency of the optical waveguide, an imprinting adhesive with a refractive index higher than that of the substrate material is typically chosen as the material constituting the grating. Therefore, in this design, when an imprinting adhesive layer with a higher refractive index exists on the surface of the low-refractive-index optical waveguide substrate, according to Fresnel's equations, more light energy is reflected back to the original medium when incident from a low-refractive-index medium to a high-refractive-index medium, resulting in a significant increase in the surface reflectivity of the non-grating region. Therefore, in this embodiment, the non-grating region on the optical waveguide substrate, excluding the grating region, is treated as a glare suppression region to reduce the reflectivity of the non-grating region of the optical waveguide structure, thereby mitigating the glare effect when external light shines on the non-grating region and suppressing the glare effect occurring in the optical waveguide structure. As shown in Figure 4, as an example, since the significant increase in surface reflectivity in the non-grating region is caused by the imprinted adhesive layer with a higher refractive index, this embodiment can perform partitioned homogenization of the imprinted adhesive in the grating region of the optical waveguide substrate, that is, homogenize only the grating region of the optical waveguide substrate. This allows for imprinting and curing of the grating region of the optical waveguide substrate, resulting in an optical waveguide structure without imprinted adhesive in the non-grating region, thus avoiding the glare effect caused by the high refractive index of the imprinted adhesive layer. As another example, this embodiment can also perform spin-coating homogenization of the imprinted adhesive on the optical waveguide substrate, that is, uniformly applying the imprinted adhesive to the entire optical waveguide substrate. Then, the grating region of the optical waveguide substrate is imprinted and cured. At this time, an imprinted adhesive layer will also exist in the non-grating region of the optical waveguide substrate other than the grating region. A first glare suppression layer is deposited on the non-grating region of the optical waveguide substrate other than the grating region to obtain an optical waveguide structure, wherein the first glare suppression layer is used to reduce the reflectivity of the non-grating region of the optical waveguide structure. It is understandable that, due to the different structures of devices employing optical waveguide structures, ambient light may not be present in the entire non-grating area. Therefore, the first glare suppression layer deposited on the printing adhesive within the non-grating area may cover only a portion of the non-grating area or cover the entire non-grating area. The portion covered by the first glare suppression layer is the area on the printing adhesive within the non-grating area where ambient light is present.

[0090] Therefore, this embodiment can also reduce glare by adding a coating to change the refractive index of the optical waveguide substrate surface.

[0091] This embodiment also provides another optical waveguide structure, which can achieve the same purpose of suppressing glare effect based on the existing optical waveguide structure. The optical waveguide substrate in the glare suppression region is configured with an imprinted adhesive on its surface, and at least a portion of the imprinted adhesive is provided with a first glare suppression layer. The first glare suppression layer is used to reduce the reflectivity of the non-grating area of ​​the optical waveguide structure.

[0092] This embodiment can also reduce the reflectivity of the non-grating region by depositing a second glare suppression layer on the imprinted adhesive in the non-grating region of the optical waveguide substrate. In this embodiment, a first glare suppression layer can be deposited on the imprinted adhesive in the non-grating region of the optical waveguide substrate using methods such as physical vapor deposition or inkjet printing. This first glare suppression layer can consist of one or more first anti-reflective film layers. For example, the first glare suppression layer includes a first anti-reflective film layer on the optical waveguide substrate, where the refractive index of the first anti-reflective film layer is less than the refractive index of the imprinted adhesive. It is understood that the refractive index of the first anti-reflective film layer needs to be greater than the refractive index of air. Alternatively, the first glare suppression layer can also include at least two first anti-reflective film layers on the imprinted adhesive, where the refractive index of the second anti-reflective film layer furthest from the imprinted adhesive is less than or equal to the refractive index of the optical waveguide substrate.

[0093] Furthermore, this embodiment provides a specific example for illustration: As shown in Figure 5, this example provides a commonly available primitive optical waveguide structure, which includes an optical waveguide substrate with a refractive index of 1.58 and an imprinted adhesive with a refractive index of 1.7 and a thickness of 0.35 micrometers on the substrate. Referring to Figure 6, the horizontal axis of the left-hand graph in Figure 6 represents the incident angle, the vertical axis represents the wavelength, and the color depth represents the reflectivity. The right-hand graph in Figure 6 describes the average reflectivity of the solid surface at a perpendicular incident angle, with the horizontal axis representing the wavelength and the vertical axis representing the reflectivity. As shown in Figure 6, the reflectivity of this primitive waveguide structure is within the wavelength range of 400nm-800nm, and the reflectivity of ambient light with an incident angle of 0-60° can reach a maximum of about 10%, which will produce a relatively strong glare effect. Referring to Figure 7, Figure 7 is a test result diagram of the optical waveguide structure in this embodiment involving the glare suppression region, which includes an optical waveguide substrate without imprinted adhesive on its surface. In Figure 7, the horizontal axis of the left-hand chart represents the angle of incidence, the vertical axis represents the wavelength, and the color depth represents the reflectivity. The right-hand chart in Figure 7 describes the average reflectivity of the solid surface at a perpendicular angle of incidence; the horizontal axis of the right-hand chart represents the wavelength, and the vertical axis represents the reflectivity. As shown in Figure 7, in this embodiment, the glare suppression area includes an optical waveguide substrate without surface-pressed adhesive, reducing the overall reflectivity to approximately 5%. Compared to the original optical waveguide structure, where the maximum reflectivity of ambient light reaches approximately 10%, this embodiment represents a certain improvement.

[0094] In some embodiments, when there is no imprinted adhesive on the surface of the optical waveguide substrate within the glare suppression region, the glare suppression region further includes a second glare suppression layer disposed on at least a portion of the optical waveguide substrate.

[0095] It is understandable that, due to the different structures of devices employing optical waveguide structures, ambient light may not be present in the entire non-grating area. Therefore, the second glare suppression layer deposited on the optical waveguide substrate within the non-grating area may cover only a portion of the non-grating area or cover the entire non-grating area. The portion covered by the second glare suppression layer is the area within the non-grating area where ambient light is present.

[0096] For the glare suppression region including the optical waveguide substrate without surface imprinting adhesive, in order to further improve the glare effect in the non-grating region, this embodiment can further reduce the reflectivity of the non-grating region by depositing a second glare suppression layer on the non-grating region of the optical waveguide substrate. This embodiment can deposit the second glare suppression layer on the non-grating region of the optical waveguide substrate using methods such as physical vapor deposition or inkjet printing. The second glare suppression layer can consist of one or more second anti-reflective films. For example, the second glare suppression layer includes one second anti-reflective film on the optical waveguide substrate, where the refractive index of the second anti-reflective film is less than the refractive index of the optical waveguide substrate. It is understood that the refractive index of the second anti-reflective film needs to be greater than the refractive index of air; alternatively, the second glare suppression layer can also include at least two second anti-reflective films on the optical waveguide substrate, where the refractive index of the second anti-reflective film farthest from the optical waveguide substrate is less than or equal to the refractive index of the optical waveguide substrate.

[0097] In some embodiments, the second glare suppression layer includes a second anti-reflection film layer on the optical waveguide substrate, wherein the refractive index of the second anti-reflection film layer is less than the refractive index of the optical waveguide substrate; or,

[0098] The second glare suppression layer includes at least two second anti-reflection film layers on the optical waveguide substrate, wherein the refractive index of the second anti-reflection film layer farthest from the optical waveguide substrate is less than or equal to the refractive index of the optical waveguide substrate.

[0099] As shown in Figure 8, in this embodiment, the second glare suppression layer includes a second anti-reflection film layer on the optical waveguide substrate. The refractive index of the second anti-reflection film layer is less than that of the optical waveguide substrate. It can be understood that the refractive index of the second anti-reflection film layer needs to be greater than that of air. Thus, this second anti-reflection film layer serves as a transition between the refractive index of the optical waveguide substrate and air, reducing reflection caused by abrupt changes in refractive index.

[0100] As shown in Figure 9, in this embodiment, the second glare suppression layer may also include at least two second anti-reflective film layers on the optical waveguide substrate. The refractive index of the second anti-reflective film layer farthest from the optical waveguide substrate is less than or equal to the refractive index of the optical waveguide substrate. It is understood that only two second anti-reflective film layers are shown in Figure 9; in reality, the second glare suppression layer may include more first anti-reflective film layers. As an example, the at least two second anti-reflective film layers may be multiple coatings with alternating first and second refractive indices, wherein the first refractive index is greater than the second refractive index, and the second refractive index is less than or equal to the refractive index of the optical waveguide substrate. The multiple coatings with alternating first and second refractive indices utilize the interference effect; through the alternating arrangement of coatings with different refractive indices, some reflected light waves cancel each other out, thereby reducing reflectivity. As another example, at least two second antireflective coating layers can be multiple coatings with continuously decreasing refractive indices. The refractive index of the second antireflective coating layers gradually decreases from the second antireflective coating layer closest to the optical waveguide substrate to the second antireflective coating layer farthest from the optical waveguide substrate (i.e., in the direction from the optical waveguide substrate to air). Multiple coatings with continuously decreasing refractive indices can smoothly transition the refractive index difference between the optical waveguide substrate and air, reducing reflection at the interface and achieving the same effect of reducing reflectivity. It is understood that in this embodiment, the thickness of each second antireflective coating layer can be determined by simulating the refractive index and thickness of the optical waveguide substrate and the refractive index of the second antireflective coating layer, based on the refractive index of the selected coating material, to obtain the theoretical reflectivity corresponding to the optional thickness of the second antireflective coating layer. Then, a target thickness is selected from the optional thicknesses based on the theoretical reflectivity. Referring to Figures 10 and 11, Figure 10 illustrates the correspondence between the optional thickness and theoretical reflectivity of the second antireflective coating layer in a scenario where the second glare suppression layer includes a second antireflective coating layer on the optical waveguide substrate. Figure 11 illustrates the relationship between the selectable thickness and theoretical reflectivity of the second anti-reflective film layer in a scenario where the second glare suppression layer includes at least two second anti-reflective film layers on the optical waveguide substrate. In Figure 10, the horizontal axis represents the selectable thickness, and the vertical axis represents the theoretical reflectivity. In Figure 11, the horizontal and vertical axes represent the selectable thicknesses of the two second anti-reflective film layers, respectively, and the vertical axis represents the theoretical reflectivity. Therefore, in this embodiment, the selectable thickness with the lowest theoretical reflectivity can be selected as the target thickness.

[0101] In one embodiment, the thickness of the second antireflective coating is determined based on the geometry and refractive index of the optical waveguide substrate and the refractive index of the second antireflective coating.

[0102] Since the geometry and refractive index of the optical waveguide substrate, as well as the thickness and refractive index of the second anti-reflective coating, all affect the reflectivity, and the geometry and refractive index of the optical waveguide substrate and the refractive index of the second anti-reflective coating are relatively fixed parameters, this embodiment can determine the thickness of the second anti-reflective coating based on the geometry and refractive index of the optical waveguide substrate and the refractive index of the second anti-reflective coating. For example, this embodiment can obtain the geometry and refractive index of the optical waveguide substrate; construct an optical waveguide structure simulation model based on the geometry and refractive index of the optical waveguide substrate and the refractive index of the second anti-reflective coating; simulate a first selectable thickness of the second anti-reflective coating based on the optical waveguide structure simulation model to obtain the theoretical reflectivity of the optical waveguide structure corresponding to the first selectable thickness; and select the thickness of the second anti-reflective coating from the first selectable thicknesses based on the theoretical reflectivity. This allows obtaining the thickness of the second anti-reflective coating when the theoretical reflectivity is lowest, and then depositing a second glare suppression layer according to the thickness of the second anti-reflective coating helps to further reduce the reflectivity of the optical waveguide structure.

[0103] In one embodiment of this application, the optical waveguide structure includes: an optical waveguide substrate; a grating region on the optical waveguide substrate, wherein the grating structure within the grating region is composed of cured imprinted adhesive; and a non-grating region on the optical waveguide substrate other than the grating region, which is a glare suppression region. The optical waveguide substrate within the glare suppression region is configured such that: a. there is no imprinted adhesive on the surface, or b. there is imprinted adhesive on the surface, and at least a portion of the imprinted adhesive is further provided with a first glare suppression layer, which is used to reduce the reflectivity of the non-grating region of the optical waveguide structure. Therefore, this embodiment, by treating the non-grating region on the optical waveguide substrate (excluding the grating region) with either no imprinted adhesive or by adding a first glare suppression layer, reduces the glare effect when external light shines on the non-grating region during the use of the AR device, thus suppressing the glare effect present in existing optical waveguide structures.

[0104] As shown in Figure 12, this application embodiment also provides an optical waveguide structure. When there is imprinted adhesive on the surface of the optical waveguide substrate within the glare suppression region, the first glare suppression layer includes a first antireflective film layer on the optical waveguide substrate, wherein the refractive index of the first antireflective film layer is less than the refractive index of the imprinted adhesive; or,

[0105] The first glare suppression layer includes at least two first antireflective film layers on the imprinting adhesive, wherein the refractive index of the first antireflective film layer furthest from the imprinting adhesive is less than or equal to the refractive index of the imprinting adhesive.

[0106] As shown in Figure 13, in this embodiment, the first glare suppression layer includes a first anti-reflective film layer on the optical waveguide substrate. The refractive index of the first anti-reflective film layer is less than the refractive index of the imprinting adhesive. It can be understood that the refractive index of the first anti-reflective film layer needs to be greater than the refractive index of air. This first anti-reflective film layer serves as a transition between the refractive index of the imprinting adhesive and air, reducing reflection caused by abrupt changes in refractive index. As a specific example, this example still uses a common existing original optical waveguide structure, which includes an optical waveguide substrate with a refractive index of 1.58 and an imprinting adhesive with a refractive index of 1.7 and a thickness of 0.35 micrometers on the substrate. Referring to Figure 14, the horizontal axis of the left-hand graph in Figure 14 represents the incident angle, the vertical axis represents the wavelength, and the color depth represents the reflectivity. The right-hand graph in Figure 14 describes the average reflectivity of the solid surface at a perpendicular incident angle; the horizontal axis of the right-hand graph represents the wavelength, and the vertical axis represents the reflectivity. In this embodiment, a material with a lower refractive index than the printing adhesive is selected as the first anti-reflective coating layer. For example, SiO2 can be used. After simulation, when the target thickness of SiO2 is selected as 0.095 μm, the reflectivity can be reduced to 2.5%. Of course, to further improve the suppression of glare, a material with an even lower refractive index can be selected as the first anti-reflective coating layer. See Figure 15. In the graph on the left side of Figure 15, the horizontal axis is the incident angle, the vertical axis is the wavelength, and the color depth is the reflectivity. The graph on the right side of Figure 15 describes the average reflectivity of the solid surface at a vertical incident angle. The horizontal axis of the right graph is the wavelength, and the vertical axis is the reflectivity. In this embodiment, a material with a refractive index of 1.4 is selected as the first anti-reflective coating layer. Similarly, after simulation, a material with a refractive index of 1.4 and a target thickness of 0.1 μm is selected, which can achieve a reflectivity of 1%-2%. In this embodiment, when the first glare suppression layer includes a first anti-reflection film layer on the optical waveguide substrate, the reflectivity will decrease more significantly when the refractive index of this first anti-reflection film layer is lower than that of the imprinting adhesive, that is, the better the suppression of glare effect.

[0107] As shown in Figure 16, in this embodiment, the first glare suppression layer may also include at least two first antireflective film layers on the imprinting adhesive, and the refractive index of the second antireflective film layer furthest from the imprinting adhesive is less than or equal to the refractive index of the optical waveguide substrate. It is understood that only two second antireflective film layers are shown in Figure 16; in reality, the second glare suppression layer may include more first antireflective film layers. As an example, the at least two second antireflective film layers may be multiple coatings with alternating second and fourth refractive indices, wherein the second refractive index is greater than the fourth refractive index, and the fourth refractive index is less than or equal to the refractive index of the imprinting adhesive. The multiple coatings with alternating second and fourth refractive indices utilize the interference effect; through the alternating arrangement of coatings with different refractive indices, some reflected light waves cancel each other out, thereby reducing reflectivity. As another example, the at least two first antireflective film layers may be multiple coatings with continuously decreasing refractive indices. Multiple coatings with continuously decreasing refractive indices can smoothly transition the refractive index difference between the imprinting adhesive and air, reducing reflection at the interface, and similarly achieving the effect of reducing reflectivity. As a specific example, this example still uses a common existing original optical waveguide structure, which includes an optical waveguide substrate with a refractive index of 1.58 and an imprinted adhesive with a refractive index of 1.7 and a thickness of 0.35 micrometers on the substrate. Referring to Figure 17, the horizontal axis of the left graph in Figure 17 represents the incident angle, the vertical axis represents the wavelength, and the color depth represents the reflectivity. The right graph in Figure 17 describes the average reflectivity of the solid surface at a perpendicular incident angle, with the horizontal axis representing the wavelength and the vertical axis representing the reflectivity. In this embodiment, SiO2 and a material with a refractive index of 1.3 are selected as the first antireflective film layer. Similarly, after simulation, a material with a refractive index of 1.3 and a target thickness of 0.09 μm and a target thickness of 0.04 μm of SiO2 are selected. This embodiment can suppress the reflectivity of the main visible wavelength band to below 0.5%. Compared with a single-layer film structure, the multi-layer film structure has a better glare suppression effect.

[0108] In one embodiment, the thickness of the first antireflective film is determined based on the geometry and refractive index of the optical waveguide substrate, the thickness and refractive index of the adhesive layer in the glare suppression region, and the refractive index of the first antireflective film.

[0109] Similarly, the glare suppression region in this optical waveguide structure also contains imprinted adhesive. Since the reflectivity is affected by the different geometric shapes and refractive indices of the optical waveguide substrate, the adhesive layer thickness and refractive index within the glare suppression region, and the film thickness and refractive index of the first antireflective film, all these factors influence the reflectivity. Since the geometric shapes and refractive indices of the optical waveguide substrate, the adhesive layer thickness and refractive index within the glare suppression region, and the refractive index of the first antireflective film are relatively fixed parameters, this embodiment can determine the film thickness of the first antireflective film based on the geometric shapes and refractive indices of the optical waveguide substrate, the adhesive layer thickness and refractive index within the glare suppression region, and the refractive index of the first antireflective film. For example, this embodiment can obtain the geometry and refractive index of the optical waveguide substrate, as well as the thickness and refractive index of the adhesive layer in the glare suppression region; construct an optical waveguide structure simulation model based on the geometry and refractive index of the optical waveguide substrate, the thickness and refractive index of the adhesive layer in the glare suppression region, and the refractive index of the first anti-reflection film; simulate a second optional thickness of the first anti-reflection film based on the optical waveguide structure simulation model to obtain the theoretical reflectivity of the optical waveguide structure corresponding to the second optional thickness; select the film thickness of the first anti-reflection film from the second optional thickness based on the theoretical reflectivity. This allows obtaining the film thickness of the first anti-reflection film when the theoretical reflectivity is lowest, and then depositing the first glare suppression layer according to the film thickness of the first anti-reflection film helps to further reduce the reflectivity of the optical waveguide structure.

[0110] It is understood that in this embodiment, the thickness of each first antireflective film layer can be obtained by simulation based on the refractive index of the film material selected for the first antireflective film layer, the refractive index and thickness of the optical waveguide substrate and the imprint adhesive, and the refractive index of the first antireflective film layer. The theoretical reflectivity corresponding to the optional thickness of the first antireflective film layer is then obtained, and the target thickness of the first antireflective film layer is selected from the optional thicknesses based on the theoretical reflectivity.

[0111] In another embodiment of this application, the glare suppression region includes an optical waveguide substrate with imprinted adhesive on its surface, and a first glare suppression layer on the imprinted adhesive. Therefore, this embodiment does not require changing the existing spin-coating process; simply depositing the first glare suppression layer on the imprinted adhesive in the non-grating area after imprinting and curing effectively suppresses the glare effect. This embodiment effectively suppresses the glare effect of the optical waveguide structure while reducing process modification costs.

[0112] Referring to Figure 18, which is a flowchart of the first embodiment of the fabrication method of the optical waveguide structure of this application.

[0113] In this embodiment, the fabrication method of the optical waveguide structure includes steps S10 to S30:

[0114] Step S10: Partition and homogenize the adhesive in the grating region of the optical waveguide substrate.

[0115] Step S20: Provide a master template for grating structure imprinting, and use the master template for grating structure imprinting to imprint the imprinting adhesive on the optical waveguide substrate to form a grating structure within the grating region of the optical waveguide substrate.

[0116] Step S30: The imprinted adhesive is cured and the master template of the grating structure is demolded from the imprinted adhesive to obtain the optical waveguide structure.

[0117] It should be noted that the optical waveguide substrate is a matrix of an optical waveguide structure made of inorganic or polymeric light-transmitting materials, and the imprinting adhesive is a thermosensitive or photosensitive curing adhesive with good light transmittance used in the nanoimprinting process.

[0118] Additionally, it should be noted that the fabrication method of this embodiment is applicable to optical waveguide structures where the non-grating region is an optical waveguide substrate without surface imprinting adhesive.

[0119] As shown in Figure 19, in this embodiment, imprinting adhesive is uniformly sprayed onto the grating area of ​​the optical waveguide substrate using a printing nozzle, thereby achieving partitioned and uniform application of the imprinting adhesive to the grating area of ​​the optical waveguide substrate. Furthermore, in this embodiment, the imprinting adhesive in the grating area of ​​the optical waveguide substrate is imprinted onto a master template corresponding to the grating structure within the grating area, thus forming the grating within the grating area. The imprinted imprinting adhesive is then cured, and the master template imprinted with the grating structure is demolded from the imprinting adhesive to obtain the optical waveguide structure. Therefore, since the significant increase in surface reflectivity in the non-grating area is caused by the imprinting adhesive layer with a higher refractive index, this embodiment can perform partitioned and uniform application of the imprinting adhesive to the grating area of ​​the optical waveguide substrate, that is, uniform application is only performed on the grating area of ​​the optical waveguide substrate. Thus, the grating area of ​​the optical waveguide substrate is imprinted and cured, resulting in an optical waveguide structure without imprinting adhesive in the non-grating area. The glare suppression area includes an optical waveguide substrate without imprinting adhesive on its surface, thereby avoiding the glare effect caused by the high refractive index of the imprinting adhesive layer.

[0120] In some embodiments, after the steps of curing the imprinted adhesive and demolding the master template of the grating structure imprint from the imprinted adhesive in step S30, step 31 is included:

[0121] Step S31: A second glare suppression layer is deposited on the non-grating region other than the grating region on the optical waveguide substrate, wherein the second glare suppression layer is used to reduce the reflectivity of the non-grating region of the optical waveguide structure.

[0122] To further improve the suppression of glare, this embodiment involves imprinting and curing the grating region of the optical waveguide substrate, and then depositing a second glare suppression layer on the non-grating region of the optical waveguide substrate, excluding the grating region, to obtain an optical waveguide structure. The second glare suppression layer is used to reduce the reflectivity of the non-grating region of the optical waveguide structure. This embodiment can deposit the second glare suppression layer on the non-grating region of the optical waveguide substrate using methods such as physical vapor deposition or inkjet printing. The second glare suppression layer can consist of one or more second anti-reflective films. For example, the second glare suppression layer includes one second anti-reflective film on the optical waveguide substrate, where the refractive index of the second anti-reflective film is less than the refractive index of the optical waveguide substrate. It is understood that the refractive index of the second anti-reflective film needs to be greater than the refractive index of air. Alternatively, the second glare suppression layer may also include at least two second anti-reflective films on the optical waveguide substrate, where the refractive index of the second anti-reflective film farthest from the optical waveguide substrate is less than or equal to the refractive index of the optical waveguide substrate.

[0123] In some embodiments, the second glare suppression layer includes a second anti-reflection film layer on the optical waveguide substrate, wherein the refractive index of the second anti-reflection film layer is less than the refractive index of the optical waveguide substrate;

[0124] Alternatively, the second glare suppression layer includes at least two second anti-reflective film layers on the optical waveguide substrate, wherein the refractive index of the second anti-reflective film layer furthest from the optical waveguide substrate is less than or equal to the refractive index of the optical waveguide substrate.

[0125] In this embodiment, a second glare suppression layer can be deposited on the non-grating area of ​​the optical waveguide substrate using methods such as physical vapor deposition or inkjet printing. This glare suppression layer can consist of one or more second anti-reflective film layers. As shown in Figure 20, for example, the second glare suppression layer includes a second anti-reflective film layer on the optical waveguide substrate. The refractive index of the second anti-reflective film layer is less than the refractive index of the optical waveguide substrate. It can be understood that the refractive index of the second anti-reflective film layer needs to be greater than the refractive index of air. Thus, this second anti-reflective film layer acts as a refractive index transition between the optical waveguide substrate and air, reducing reflection caused by abrupt changes in refractive index.

[0126] As shown in Figure 21, the second glare suppression layer may also include at least two second antireflective coating layers on the optical waveguide substrate, wherein the refractive index of the second antireflective coating layer farthest from the optical waveguide substrate is less than or equal to the refractive index of the optical waveguide substrate. As an example, the at least two second antireflective coating layers may be multiple coatings with alternating first and second refractive indices, wherein the first refractive index is greater than the second refractive index, and the second refractive index is less than or equal to the refractive index of the optical waveguide substrate. The multiple coatings with alternating first and second refractive indices utilize the interference effect; through the alternating arrangement of coatings with different refractive indices, some reflected light waves cancel each other out, thereby reducing reflectivity. As another example, the at least two second antireflective coating layers may be multiple coatings with continuously decreasing refractive indices. Multiple coatings with continuously decreasing refractive indices can smoothly transition the refractive index difference between the optical waveguide substrate and air, reducing reflection at the interface, thus also achieving the effect of reducing reflectivity. It is understood that in this embodiment, the thickness of each second antireflective film layer can be obtained by simulation based on the refractive index of the film material selected for the second antireflective film layer, the refractive index and thickness of the optical waveguide substrate, and the refractive index of the second antireflective film layer, to obtain the theoretical reflectivity corresponding to the optional thickness of the second antireflective film layer, and then selecting the target thickness from the optional thickness based on the theoretical reflectivity.

[0127] In one embodiment, prior to the step of depositing a second glare suppression layer on the non-grating region of the optical waveguide substrate, excluding the grating region, the method includes:

[0128] Step S21: Obtain the geometry and refractive index of the optical waveguide substrate;

[0129] Step S22: Based on the geometry and refractive index of the optical waveguide substrate and the refractive index of the second anti-reflection film, construct a simulation model of the optical waveguide structure.

[0130] Step S23: Based on the simulation model of the optical waveguide structure, the first optional thickness of the second anti-reflection film is simulated to obtain the theoretical reflectivity of the optical waveguide structure corresponding to the first optional thickness;

[0131] Step S24: Select the thickness of the second antireflective film from the first selectable thicknesses based on the theoretical reflectivity.

[0132] Since the geometry and refractive index of the optical waveguide substrate, as well as the thickness and refractive index of the second anti-reflective coating, all affect the reflectivity, and the geometry and refractive index of the optical waveguide substrate and the refractive index of the second anti-reflective coating are relatively fixed parameters, this embodiment can determine the thickness of the second anti-reflective coating based on the geometry and refractive index of the optical waveguide substrate and the refractive index of the second anti-reflective coating. For example, this embodiment can obtain the geometry and refractive index of the optical waveguide substrate; construct an optical waveguide structure simulation model based on the geometry and refractive index of the optical waveguide substrate and the refractive index of the second anti-reflective coating; simulate a first selectable thickness of the second anti-reflective coating based on the optical waveguide structure simulation model to obtain the theoretical reflectivity of the optical waveguide structure corresponding to the first selectable thickness; and select the thickness of the second anti-reflective coating from the first selectable thicknesses based on the theoretical reflectivity. This allows obtaining the thickness of the second anti-reflective coating when the theoretical reflectivity is lowest, and then depositing the second glare suppression layer according to the thickness of the second anti-reflective coating. Therefore, this embodiment helps to further reduce the reflectivity of the optical waveguide structure by finely controlling the thickness of each second antireflection film layer in the second glare suppression layer.

[0133] In one embodiment of the preparation method of this application, the grating region of the optical waveguide substrate is imprinted with adhesive in a partitioned and homogenized manner, and then the grating region of the optical waveguide substrate is imprinted and cured to obtain an optical waveguide structure. Therefore, the optical waveguide structure prepared in this embodiment does not have high-refractive-index imprinted adhesive in the non-grating regions of the optical waveguide substrate other than the grating region, thereby reducing the reflectivity of the non-grating regions. This reduces the glare effect when external light shines on the non-grating regions during the use of AR devices, thus suppressing the glare effect of the optical waveguide structure.

[0134] Referring to Figure 22, which is a flowchart of the second embodiment of the method for fabricating the optical waveguide structure of this application.

[0135] In this embodiment, the fabrication method of the optical waveguide structure includes steps A10 to A40:

[0136] Step A10: Spin-coating the optical waveguide substrate with imprinting adhesive.

[0137] Step A20: Provide a master template for grating structure imprinting, and use the master template for grating structure imprinting to imprint the imprinting adhesive on the optical waveguide substrate to form a grating structure within the grating region of the optical waveguide substrate;

[0138] Step A30: Cure the imprinted adhesive and demold the master template of the grating structure imprint from the imprinted adhesive.

[0139] Step A40: A first glare suppression layer is deposited on the non-grating region other than the grating region on the optical waveguide substrate to obtain an optical waveguide structure, wherein the first glare suppression layer is used to reduce the reflectivity of the non-grating region of the optical waveguide structure.

[0140] It should be noted that the fabrication method of this embodiment is applicable to optical waveguide structures where the non-grating region is an optical waveguide substrate with imprinted adhesive on its surface.

[0141] As shown in Figure 23, in this embodiment, a spin coating operation is used to uniformly coat the optical waveguide substrate with imprinting adhesive, forming a uniform thin film of imprinting adhesive on the optical waveguide substrate. Then, in this embodiment, the imprinting adhesive within the grating region of the optical waveguide substrate is imprinted onto the grating region using a master template corresponding to the grating structure, thereby forming the grating within the grating region and performing a curing process. Because a spin coating method is used, an imprinting adhesive layer exists on the surface of the non-grating areas of the optical waveguide substrate.

[0142] As shown in Figure 24, in this embodiment, a first glare suppression layer can be deposited on the non-grating region (excluding the grating region) of the optical waveguide substrate to obtain an optical waveguide structure. The first glare suppression layer is used to reduce the reflectivity of the non-grating region of the optical waveguide structure. The first glare suppression layer includes a coating that reduces reflectivity. For example, the first glare suppression layer may include a first anti-reflection film layer on the optical waveguide substrate, where the refractive index of the first anti-reflection film layer is less than the refractive index of the imprinting adhesive. Alternatively, the first glare suppression layer may include at least two first anti-reflection film layers on the imprinting adhesive, where the refractive index of the first anti-reflection film layer furthest from the imprinting adhesive is less than or equal to the refractive index of the imprinting adhesive.

[0143] In one embodiment, the first glare suppression layer includes a first anti-reflection film layer on the optical waveguide substrate, wherein the refractive index of the first anti-reflection film layer is less than the refractive index of the imprinting adhesive;

[0144] Alternatively, the first glare suppression layer includes at least two first antireflective film layers on the imprinting adhesive, wherein the refractive index of the first antireflective film layer furthest from the imprinting adhesive is less than or equal to the refractive index of the imprinting adhesive.

[0145] In this embodiment, a second glare suppression layer can be deposited on the imprinted adhesive in the non-grating area of ​​the optical waveguide substrate using methods such as physical vapor deposition or inkjet printing. This first glare suppression layer can consist of one or more first anti-reflective film layers. As shown in Figure 24, exemplarily, the first glare suppression layer includes a first anti-reflective film layer on the optical waveguide substrate. The refractive index of the first anti-reflective film layer is less than the refractive index of the imprinted adhesive. It is understood that the refractive index of the first anti-reflective film layer needs to be greater than the refractive index of air. Thus, this first anti-reflective film layer serves as a refractive index transition between the optical waveguide substrate and air, reducing reflections caused by abrupt changes in refractive index.

[0146] As shown in Figure 25, the first glare suppression layer may also include at least two first antireflective film layers on the imprinting adhesive, wherein the refractive index of the first antireflective film layer furthest from the imprinting adhesive is less than or equal to the refractive index of the imprinting adhesive. It is understood that, due to the different materials of the multiple first antireflective film layers, the coating processes that may be used may also differ; therefore, multiple coating processes can be used alternately. As an example, the at least two second antireflective film layers may be multiple coating layers with alternating second and fourth refractive indices, wherein the second refractive index is greater than the fourth refractive index, and the fourth refractive index is less than or equal to the refractive index of the imprinting adhesive. The multiple coating layers with alternating second and fourth refractive indices utilize the interference effect; through the alternating arrangement of coating layers with different refractive indices, some reflected light waves cancel each other out, thereby reducing reflectivity. As another example, the at least two first antireflective film layers may be multiple coating layers with continuously decreasing refractive indices. Multiple coating layers with continuously decreasing refractive indices can smoothly transition the refractive index difference between the imprinting adhesive and air, reducing reflection at the interface, and similarly achieving the effect of reducing reflectivity. It is understood that in this embodiment, the thickness of each first antireflective film layer can be obtained by simulation based on the refractive index of the film material selected for the first antireflective film layer, the refractive index and thickness of the optical waveguide substrate and the imprint adhesive, and the refractive index of the first antireflective film layer. The theoretical reflectivity corresponding to the optional thickness of the first antireflective film layer is then obtained, and the target thickness of the first antireflective film layer is selected from the optional thicknesses based on the theoretical reflectivity.

[0147] In one embodiment, prior to the step A40 of depositing a first glare suppression layer on the non-grating region of the optical waveguide substrate other than the grating region, the method includes:

[0148] Step A41: Obtain the geometry and refractive index of the optical waveguide substrate, as well as the thickness and refractive index of the imprinted adhesive layer in the non-grating region;

[0149] Step A42: Based on the geometry and refractive index of the optical waveguide substrate, the thickness and refractive index of the imprinted adhesive layer, and the refractive index of the first antireflective film layer, construct a simulation model of the optical waveguide structure.

[0150] Step A43: Based on the optical waveguide structure simulation model, simulate the second optional thickness of the first anti-reflection film layer to obtain the theoretical reflectivity of the optical waveguide structure corresponding to the second optional thickness;

[0151] Step A44: Select the thickness of the first antireflective film from the second selectable thicknesses based on the theoretical reflectivity.

[0152] Similarly, the glare suppression region in this optical waveguide structure also contains imprinted adhesive. Since the reflectivity is affected by the different geometric shapes and refractive indices of the optical waveguide substrate, the adhesive layer thickness and refractive index within the glare suppression region, and the film thickness and refractive index of the first antireflective film, all these factors influence the reflectivity. Since the geometric shapes and refractive indices of the optical waveguide substrate, the adhesive layer thickness and refractive index within the glare suppression region, and the refractive index of the first antireflective film are relatively fixed parameters, this embodiment can determine the film thickness of the first antireflective film based on the geometric shapes and refractive indices of the optical waveguide substrate, the adhesive layer thickness and refractive index within the glare suppression region, and the refractive index of the first antireflective film. For example, this embodiment can obtain the geometry and refractive index of the optical waveguide substrate, as well as the thickness and refractive index of the adhesive layer in the glare suppression region; construct an optical waveguide structure simulation model based on the geometry and refractive index of the optical waveguide substrate, the thickness and refractive index of the adhesive layer in the glare suppression region, and the refractive index of the first anti-reflection film; simulate a second optional thickness of the first anti-reflection film based on the optical waveguide structure simulation model to obtain the theoretical reflectivity of the optical waveguide structure corresponding to the second optional thickness; select the film thickness of the first anti-reflection film from the second optional thickness based on the theoretical reflectivity. This allows obtaining the film thickness of the first anti-reflection film when the theoretical reflectivity is lowest, and then depositing the first glare suppression layer according to the film thickness of the first anti-reflection film. This embodiment also additionally considers the influence of the adhesive layer on the reflectivity layer, used for fine control of the film thickness of each first anti-reflection film in the first glare suppression layer, which helps to further reduce the reflectivity of the optical waveguide structure.

[0153] In another embodiment of the preparation method of this application, the grating region of the optical waveguide substrate is imprinted and cured by spin-coating an imprinting adhesive onto the substrate. A first glare suppression layer is then deposited on the non-grating region of the optical waveguide substrate, excluding the grating region, to obtain the optical waveguide structure. The first glare suppression layer is used to reduce the reflectivity of the non-grating region of the optical waveguide structure. Therefore, this embodiment does not require changing the existing spin-coating process; simply depositing the first glare suppression layer on the imprinted adhesive in the non-grating region after imprinting and curing effectively suppresses glare. This embodiment effectively suppresses the glare effect of the optical waveguide structure while reducing process modification costs.

[0154] As an optional embodiment of this application, referring to Figure 26, the selection of specific process parameters in the fabrication method of the optical waveguide structure in this embodiment can be determined in the following way. This embodiment can first simulate the reflectivity of the non-grating region of the original optical waveguide structure to be improved, obtaining the reflectivity of the non-grating region of the original optical waveguide structure. It is then determined whether the reflectivity is greater than a predetermined reflection threshold (e.g., 4%, 5%, 6%) to determine whether the original optical waveguide structure needs to suppress glare. A corresponding main improvement scheme is then selected (i.e., removing the non-grating region imprinting adhesive, single-layer film, multi-layer film, etc.). Next, a film material that meets the refractive index requirements for the coating is selected from the material library. Then, after simulation based on the refractive index and thickness of the optical waveguide substrate and the imprinting adhesive, as well as the refractive index of the film material, the theoretical reflectivity corresponding to the optional thickness of the film is obtained. Finally, the target thickness of the film is selected from the optional thicknesses based on the theoretical reflectivity. Furthermore, different coating processes are used for coating the film material, corresponding to different coating processes (e.g., inkjet printing, physical vapor deposition). The main improvement scheme, the materials and target thicknesses of each film layer, and the coating process used are taken as the specific process parameters in the fabrication method of the optical waveguide structure.

[0155] Furthermore, this application embodiment also provides a head-mounted display device, which includes the optical waveguide structure described above. For example, the head-mounted display device is a device requiring optical waveguide functionality, such as AR glasses or AR helmets.

[0156] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the optical waveguide structure and its fabrication method of this application. Any simple modifications based on this technical concept are within the protection scope of this application.

Claims

1. An optical waveguide structure, characterized in that, The optical waveguide structure includes: an optical waveguide substrate; The optical waveguide substrate includes a grating region, and the grating structure within the grating region is composed of cured imprinted adhesive; The non-grating region on the optical waveguide substrate, excluding the grating region, is a glare suppression region. The optical waveguide substrate within the glare suppression region is configured as follows: a. No embossing adhesive on the surface, or b. The surface has an imprinting adhesive, and at least a portion of the imprinting adhesive is further provided with a first glare suppression layer, the first glare suppression layer being used to reduce the reflectivity of the non-grating region of the optical waveguide structure.

2. The optical waveguide structure as described in claim 1, characterized in that, When there is no embossed adhesive on the surface of the optical waveguide substrate within the glare suppression region, the glare suppression region further includes a second glare suppression layer disposed on at least a portion of the optical waveguide substrate.

3. The optical waveguide structure as described in claim 2, characterized in that, The second glare suppression layer includes a second anti-reflection film layer on the optical waveguide substrate, wherein the refractive index of the second anti-reflection film layer is less than the refractive index of the optical waveguide substrate; or, The second glare suppression layer includes at least two second anti-reflection film layers on the optical waveguide substrate, wherein the refractive index of the second anti-reflection film layer farthest from the optical waveguide substrate is less than or equal to the refractive index of the optical waveguide substrate.

4. The optical waveguide structure as described in claim 3, characterized in that, The thickness of the second antireflective coating is determined based on the geometry and refractive index of the optical waveguide substrate and the refractive index of the second antireflective coating.

5. The optical waveguide structure as described in claim 1, characterized in that, When an imprinted adhesive is present on the surface of the optical waveguide substrate within the glare suppression region, the first glare suppression layer includes a first anti-reflection film layer on the optical waveguide substrate, wherein the refractive index of the first anti-reflection film layer is less than the refractive index of the imprinted adhesive; or, The first glare suppression layer includes at least two first antireflective film layers on the imprinting adhesive, wherein the refractive index of the first antireflective film layer furthest from the imprinting adhesive is less than or equal to the refractive index of the imprinting adhesive.

6. The optical waveguide structure as described in claim 5, characterized in that, The thickness of the first antireflective film is determined based on the geometry and refractive index of the optical waveguide substrate, the thickness and refractive index of the adhesive layer in the glare suppression area, and the refractive index of the first antireflective film.

7. A method for fabricating an optical waveguide structure, characterized in that, The method for fabricating the optical waveguide structure includes: Partitioning and homogenizing the grating region of the optical waveguide substrate with imprinted adhesive; A master template for grating structure imprinting is provided. The master template for grating structure imprinting is used to imprint the imprinting adhesive on the optical waveguide substrate to form a grating structure within the grating region of the optical waveguide substrate. The imprinted adhesive is cured, and the master template of the grating structure is demolded from the imprinted adhesive to obtain the optical waveguide structure.

8. The method for fabricating the optical waveguide structure as described in claim 7, characterized in that, After the steps of curing the imprinting adhesive and demolding the master template of the grating structure imprint from the imprinting adhesive, the process includes: A second glare suppression layer is deposited on the non-grating region of the optical waveguide substrate, excluding the grating region, wherein the second glare suppression layer is used to reduce the reflectivity of the non-grating region of the optical waveguide structure.

9. The method for fabricating the optical waveguide structure as described in claim 8, characterized in that, The second glare suppression layer includes a second anti-reflection film layer on the optical waveguide substrate, wherein the refractive index of the second anti-reflection film layer is less than the refractive index of the optical waveguide substrate; Alternatively, the second glare suppression layer includes at least two second anti-reflective film layers on the optical waveguide substrate, wherein the refractive index of the second anti-reflective film layer furthest from the optical waveguide substrate is less than or equal to the refractive index of the optical waveguide substrate.

10. The method for fabricating the optical waveguide structure as described in claim 9, characterized in that, Before the step of depositing a second glare suppression layer on the non-grating region of the optical waveguide substrate, excluding the grating region, the procedure includes: Obtain the geometry and refractive index of the optical waveguide substrate; Based on the geometry and refractive index of the optical waveguide substrate and the refractive index of the second antireflection film, a simulation model of the optical waveguide structure is constructed. Based on the simulation model of the optical waveguide structure, the first optional thickness of the second antireflection film is simulated to obtain the theoretical reflectivity of the optical waveguide structure corresponding to the first optional thickness; Based on the theoretical reflectivity, the thickness of the second antireflective film is selected from the first selectable thicknesses.

11. A method for fabricating an optical waveguide structure, characterized in that, The method for fabricating the optical waveguide structure includes: Spin coating and homogenization of imprinting adhesive onto an optical waveguide substrate; A master template for grating structure imprinting is provided. The master template for grating structure imprinting is used to imprint the imprinting adhesive on the optical waveguide substrate to form a grating structure within the grating region of the optical waveguide substrate. The embossing adhesive is cured after embossing, and the master template of the grating structure embossing is demolded from the embossing adhesive; A first glare suppression layer is deposited on the non-grating region (excluding the grating region) of the optical waveguide substrate to obtain an optical waveguide structure, wherein the first glare suppression layer is used to reduce the reflectivity of the non-grating region of the optical waveguide structure.

12. The method for fabricating the optical waveguide structure as described in claim 11, characterized in that, The first glare suppression layer includes a first anti-reflection film layer on the optical waveguide substrate, wherein the refractive index of the first anti-reflection film layer is less than the refractive index of the imprinting adhesive; Alternatively, the first glare suppression layer includes at least two first antireflective film layers on the imprinting adhesive, wherein the refractive index of the first antireflective film layer furthest from the imprinting adhesive is less than or equal to the refractive index of the imprinting adhesive.

13. The method for fabricating the optical waveguide structure as described in claim 12, characterized in that, Before the step of depositing the first glare suppression layer on the non-grating region (excluding the grating region) of the optical waveguide substrate, the following steps are included: Obtain the geometry and refractive index of the optical waveguide substrate, as well as the thickness and refractive index of the imprinted adhesive layer in the non-grating region; Based on the geometry and refractive index of the optical waveguide substrate, the thickness and refractive index of the imprinted adhesive layer, and the refractive index of the first antireflective film layer, a simulation model of the optical waveguide structure is constructed. Based on the simulation model of the optical waveguide structure, the second optional thickness of the first anti-reflection film is simulated to obtain the theoretical reflectivity of the optical waveguide structure corresponding to the second optional thickness; The thickness of the first antireflective film is selected from the second selectable thicknesses based on the theoretical reflectivity.

14. A head-mounted display device, characterized in that, The head-mounted display device includes an optical waveguide structure as described in any one of claims 1 to 6.

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