Preparation method of grating structure, grating structure and near-to-eye display device

Abstract

The embodiment of the invention provides a preparation method of a grating structure, the grating structure and a near-to-eye display device. The method comprises the steps that an isolation layer is formed on the surface of a grating layer, and the grating layer is provided with a to-be-thinned area; forming a mask layer on the surface, deviating from the grating layer, of the isolation layer, wherein the mask layer is provided with a pattern area; etching positions, corresponding to the pattern area, of the isolation layer and the area to be thinned; and removing the mask layer and the isolation layer. According to the technical scheme, reaction or dissolution between the mask layer and the grating layer is prevented, and damage to the structure of the grating layer is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of optical equipment, and in particular to a method for preparing a grating structure, a grating structure and a near-eye display device. Background Art

[0002] In augmented reality and virtual reality technologies, volume holographic gratings play a vital role. Part of the volume holographic gratings achieves different modulation effects on light waves by making the thickness of different positions different. In the related art, when preparing such a volume holographic grating, usually after forming the volume holographic grating, different areas of the volume holographic grating are etched. However, due to the influence of the material, there is a possibility of mutual reaction or dissolution between the etching mask and the volume holographic material, which not only greatly limits the optional materials of the mask, but also makes it difficult to optimize the preparation process on this basis, increasing the cost of optimization. Summary of the invention

[0003] The embodiments of the present invention provide a method for preparing a grating structure, a grating structure and a near-eye display device, which are intended to prevent a reaction or dissolution between a mask layer and a grating layer, thereby avoiding damage to the structure of the grating layer.

[0004] In a first aspect, an embodiment of the present invention provides a method for preparing a grating structure, comprising:

[0005] forming an isolation layer on a surface of a grating layer, wherein the grating layer has a region to be thinned;

[0006] forming a mask layer on a surface of the isolation layer away from the grating layer, wherein the mask layer has a pattern region;

[0007] Etching the isolation layer and the area to be thinned at positions corresponding to the pattern area;

[0008] The mask layer and the isolation layer are removed.

[0009] Optionally, the isolation layer includes at least one inorganic isolation layer.

[0010] Optionally, forming an isolation layer on the surface of the grating layer includes:

[0011] forming the isolation layer on the surface of the grating layer by a thin film deposition process; or

[0012] An isolation material is coated on the surface of the grating layer to form the isolation layer.

[0013] Optionally, the thickness of the pattern area is the same at all locations; or, the thickness of the pattern area is different at least at one location.

[0014] Optionally, etching the isolation layer and the position of the area to be thinned corresponding to the pattern area includes:

[0015] The mask layer, the isolation layer and the area to be thinned are etched at positions corresponding to the pattern area.

[0016] Optionally, etching the isolation layer and the position of the area to be thinned corresponding to the pattern area includes:

[0017] The isolation layer and the area to be thinned corresponding to the pattern area are etched by a plasma etching process.

[0018] Optionally, the area to be thinned includes at least a first sub-region and a second sub-region, and a maximum value of an etching depth of the first sub-region is different from a maximum value of an etching depth of the second sub-region.

[0019] Optionally, the preparation method comprises:

[0020] forming a first isolation layer on the surface of the grating layer;

[0021] forming a first mask layer on a surface of the first isolation layer away from the grating layer, wherein the first mask layer is provided with a first pattern region;

[0022] Etching the first isolation layer and the first sub-region at positions corresponding to the first pattern region;

[0023] removing the first mask layer and the first isolation layer;

[0024] forming a second isolation layer on the surface of the grating layer;

[0025] forming a second mask layer on a surface of the second isolation layer away from the grating layer, wherein the second mask layer is provided with a second pattern region;

[0026] Etching the second isolation layer and the second sub-region at positions corresponding to the second pattern region;

[0027] The second mask layer and the second isolation layer are removed.

[0028] In a second aspect, an embodiment of the present invention further provides a grating structure, wherein the grating structure is prepared by the grating structure preparation method described above.

[0029] In a third aspect, an embodiment of the present invention further provides a near-eye display device, comprising the grating structure as described above.

[0030] The embodiment of the present invention provides a method for preparing a grating structure, a grating structure and a near-eye display device, wherein an isolation layer is formed on the surface of a grating layer, and then a mask layer is formed on the surface of the isolation layer, and then the isolation layer and the grating layer are etched so that the area to be thinned corresponds to the position of the pattern area of ​​the mask layer, so that the thickness of the area to be thinned after etching is different from the thickness of the non-thinned area, so that after removing the mask layer and the isolation layer, a grating structure with different thicknesses at different positions can be obtained. In this process, the isolation layer can separate the mask layer and the grating layer, prevent the mask layer and the grating layer from reacting or dissolving each other, and avoid the structure of the grating layer from being damaged, so as to ensure the optical performance of the grating structure, and at the same time, it is beneficial to increase the optional range of the material of the mask layer, and it is beneficial to optimize the volume holographic preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic flow chart of a method for preparing a grating structure provided by an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of the structures of the steps in a method for preparing a grating structure provided by an embodiment of the present invention;

[0034] Figure 3 A schematic structural diagram of each step in another method for preparing a grating structure provided for implementing this embodiment. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0037] It should be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0038] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0039] Please refer to Figure 1 , an embodiment of the present invention provides a method for preparing a grating structure, including steps S11 to S14.

[0040] Step S11, forming an isolation layer on the surface of the grating layer, the grating layer having a to-be-thinned area 11.

[0041] For example, Figure 2 , Figure 3 As shown in FIG. 1 (A), the grating layer 10 is formed on a waveguide substrate 20. For example, the grating layer 10 can be formed on the waveguide substrate 20 by coating a grating material on the waveguide substrate 20. The waveguide substrate 20 can be a glass substrate or a resin substrate.

[0042] Exemplarily, a functional layer, such as a transmittance-enhancing layer, a hardening layer, an orientation layer, etc., may be disposed on the waveguide substrate 20, and the grating layer 10 may be formed on the functional layer.

[0043] Optionally, the grating layer 10 includes but is not limited to a liquid crystal polarizer grating layer, a liquid crystal polarization grating layer, a volume holographic grating layer, and the like.

[0044] For example, Figure 2 , Figure 3 As shown in FIG. 2(B) , an isolation layer 30 is formed on the surface of the grating layer 10 which is away from the waveguide substrate 20 .

[0045] Step S12: forming a mask layer on a surface of the isolation layer away from the grating layer, wherein the mask layer has a pattern region.

[0046] For example, Figure 2 , Figure 3 As shown in Figures (C) and (D) in FIG. 1 , a mask layer 40 is formed on the surface of the isolation layer 30 that is away from the grating layer 10. The shape of the pattern area 41 of the mask layer 40 can match the shape of the to-be-thinned area 11 of the grating layer 10 after thinning.

[0047] Exemplarily, the mask layer 40 includes but is not limited to a photoresist layer or a photosensitive resin layer such as a photoresist or an imprint glue.

[0048] Step S13, etching the isolation layer and the area to be thinned 11 at positions corresponding to the pattern area.

[0049] For example, Figure 2 , Figure 3 As shown in Figure (E), by etching the isolation layer 30 and the position corresponding to the area to be thinned 11 and the pattern area 41, the thickness of the area to be thinned 11 of the grating layer 10 is thinned, and the thickness of the area to be thinned 11 is different from the thickness of the area not to be thinned 11 to achieve different light diffraction efficiencies.

[0050] Step S14, removing the mask layer and the isolation layer.

[0051] For example, Figure 2 , Figure 3 As shown in FIG. (F) in FIG. 1 , the remaining mask layer 40 and the isolation layer 30 disposed on the grating layer 10 are removed. Specifically, the mask layer 40 and the isolation layer 30 are removed in sequence, or the mask layer 40 and the isolation layer 30 are acted on at the same time so that the mask layer 40 and the isolation layer 30 are removed at the same time, or the isolation layer 30 and the grating layer 10 are separated, and the mask layer 40 is removed from the grating layer 10 along with the isolation layer 30.

[0052] An isolation layer 30 is formed on the surface of the grating layer 10, a mask layer 40 is formed on the surface of the isolation layer 30, and then the isolation layer 30 and the position of the to-be-thinned area 11 of the grating layer 10 corresponding to the pattern area 41 of the mask layer 40 are etched to thin the thickness of the to-be-thinned area 11 of the grating layer 10, so that the thickness of the to-be-thinned area 11 of the grating layer 10 after processing is different from the thickness of the non-thinned area 12, and finally the mask layer 40 and the isolation layer 30 are removed to obtain a grating structure 10a with different thicknesses in different areas, so that different areas of the grating structure 10a have different light diffraction effects. The preparation method utilizes an isolation layer 30 to separate the mask layer 40 and the grating layer 10, so that the mask layer 40 and the grating layer 10 are spaced apart, thereby preventing the mask layer 40 and the grating layer 10 from reacting or dissolving with each other, avoiding the structure of the grating layer 10 from being affected, ensuring that the optical performance of the grating structure 10a is better, and at the same time increasing the optional range of the mask layer 40 material, so as to optimize the preparation process and preparation cost of the grating structure 10a.

[0053] In some embodiments, the isolation layer 30 includes at least one inorganic isolation layer 30. It can be understood that the grating layer 10 and the mask layer 40 are mostly made of organic materials. Since the properties of inorganic materials and organic materials are different, and the chemical stability of inorganic materials is relatively high, by making the isolation layer 30 include at least one inorganic isolation layer 30, the inorganic isolation layer 30 is in contact with the grating layer 10, which can effectively reduce the impact of the isolation layer 30 on the grating layer 10, and after etching the isolation layer 30 and the position corresponding to the area to be thinned 11 and the pattern area 41, the isolation layer 30 and the mask layer 40 can be more conveniently removed from the grating layer 10 to ensure the structural stability of the grating structure 10a.

[0054] Optionally, the inorganic isolation layer 30 may be made of materials such as chromium oxide and silicon dioxide.

[0055] In some embodiments, when the isolation layer 30 is formed on the surface of the grating layer 10, the method includes: forming the isolation layer 30 on the surface of the grating layer 10 by a thin film deposition process. It can be understood that the thin film deposition process can form an isolation layer 30 with a uniform thickness on the grating layer 10, and ensure that the grating layer 10 and the mask layer 40 are isolated. At the same time, when etching the isolation layer 30 and the position corresponding to the area to be thinned 11 and the pattern area 41, the influence of the thickness of the isolation layer 30 on the etching process can be reduced, so that the etching depth of the grating layer 10 can be accurately controlled, and when removing the isolation layer 30 from the grating layer 10, it is more convenient to select a suitable process and reduce the influence on the grating layer 10, so as to ensure the accuracy of the formed grating structure 10a and improve the optical performance of the grating structure 10a.

[0056] For example, Figure 2 As shown, the mask layer 40 is provided with a pattern area 41, and the position of the isolation layer 30 corresponding to the pattern area 41 is exposed. When the etching conditions acting on various parts of the isolation layer 30 are the same, the thickness of the isolation layer 30 is uniform, and the isolation layer 30 can be etched simultaneously at various parts, and then the areas to be thinned 11 of the grating layer 10 corresponding to the pattern area 41 are uniformly etched simultaneously, ensuring that the thickness of the areas to be thinned 11 of the grating layer 10 is uniform after etching, thereby ensuring the structural accuracy of the grating structure 10a.

[0057] For example, the isolation layer 30 may be formed by a thin film deposition process such as evaporation or sputtering. The evaporation and sputtering methods can not only make the thickness of the isolation layer 30 uniform, but also reduce the impact on the grating layer 10 during the formation of the isolation layer 30. In addition, it is also beneficial to remove the isolation layer 30 from the grating layer 10 after etching the area 11 to be thinned of the grating layer 10.

[0058] In some embodiments, when forming the isolation layer 30 on the surface of the grating layer 10, the method includes: coating the isolation material on the surface of the grating layer 10 to form the isolation layer 30. By coating, it is advantageous to form the isolation layer 30 with uniform thickness on the grating layer 10, thereby reducing the influence of the thickness of the isolation layer 30 on the subsequent etching process, accurately controlling the etching depth of the grating layer 10, ensuring the accuracy of the formed grating structure 10a, and improving the optical performance of the grating structure 10a.

[0059] like Figure 2 As shown, in some embodiments, the thickness of the pattern area 41 is the same at various locations, or the thickness of the pattern area is different at least at one location. It can be understood that the structure of the area to be thinned 11 of the grating layer 10 after etching and thinning matches the structure of the pattern area 41 of the mask layer 40, so that the thickness of the pattern area 41 is the same at various locations, which is conducive to making the thickness of the area to be thinned 11 after etching the same, and making the thickness of the pattern area 41 different at least at one location is conducive to making the thickness of the area to be thinned 11 after etching different at least at one location. The thickness of the pattern area 41 is relatively flexible and can be adjusted according to actual conditions to meet different preparation requirements.

[0060] Exemplarily, the thickness of the pattern region 41 is the thickness of the pattern region 41 along the direction from the isolation layer 30 to the grating layer 10. Figure 2 The Z direction is shown in FIG.

[0061] It can be understood that the thickness of the pattern area 41 is greater than or equal to 0.

[0062] For example, Figure 2 As shown in FIG. 1 (D), the thickness of the pattern region 41 is 0 at all locations, so that the thickness of the area to be thinned 11 after etching is the same at all locations.

[0063] For example, Figure 3 As shown in FIG. 1 (D), the thickness of each location of the pattern region 41 is greater than 0, and the thickness of the pattern region 41 is continuously modulated, so that the thickness of the area to be thinned 11 after etching is continuously modulated.

[0064] Exemplarily, the thickness of the pattern region 41 may also change in a step-wise manner, so that the thickness of the area to be thinned 11 after etching changes in a step-wise manner.

[0065] In some embodiments, etching the isolation layer 30 and the position of the area to be thinned 11 corresponding to the pattern area 41 includes etching the mask layer 40 , the isolation layer 30 and the position of the area to be thinned 11 corresponding to the pattern area 41 .

[0066] For example, Figure 3As shown, when the thickness of the pattern area 41 is greater than 0, the positions of the isolation layer 30 and the area to be thinned 11 corresponding to the pattern area 41 are covered by the mask layer 40. When etching the positions of the isolation layer 30 and the area to be thinned 11 corresponding to the pattern area 41, it is necessary to etch part of the mask layer 40 on the isolation layer 30 and the area to be thinned 11, and then etch the isolation layer 30 and the area to be thinned 11.

[0067] Specifically, when etching the positions of the mask layer 40, the isolation layer 30 and the area to be thinned 11 corresponding to the pattern area 41, the sum of the etching depths of the mask layer 40, the isolation layer 30 and the area to be thinned 11 is equal at any position corresponding to the pattern area 41. It can be understood that the sum of the etching depths of the mask layer 40, the isolation layer 30 and the area to be thinned 11 is equal, which is conducive to ensuring that the structure of the area to be thinned 11 after etching matches the structure of the initial pattern area 41 of the mask layer 40, and ensuring the structural accuracy of the grating layer 10 after etching and the optical performance of the grating structure 10a.

[0068] Exemplarily, the etching depth is the etching depth along the direction from the isolation layer 30 to the grating layer 10, for example Figure 2 The Z direction is shown in FIG.

[0069] For example, Figure 3 As shown in FIG. (D), the thickness of the pattern region 41 is continuously modulated. Figure 3 As shown in Figure (E), when the mask layer 40, the isolation layer 30 and the area to be thinned 11 are etched, the sum of the etching depths of the mask layer 40, the isolation layer 30 and the area to be thinned 11 at each location corresponding to the pattern area 41 is equal, and the area to be thinned 11 after etching forms a structure matching the initial structure of the pattern area 41 of the mask layer 40, and the thickness of the area to be thinned 11 is continuously modulated.

[0070] In some embodiments, a mask layer 40 is formed on a surface of the isolation layer 30 that is away from the grating layer 10, and the mask layer 40 is provided with a pattern region 41, including: coating a photoresist on a surface of the isolation layer 30 that is away from the grating layer 10, such as Figure 2 , Figure 3 As shown in FIG. (C), a pattern region 41 is formed on the photoresist by a photolithography process or a nanoimprint process to obtain a mask layer 40, such as Figure 2 , Figure 3 As shown in Figure (D) in FIG. It can be understood that the mask layer 40 obtained by the photolithography process or the nanoimprint process has a high precision in the pattern area 41. Accordingly, when the isolation layer 30 and the area to be thinned 11 of the grating layer 10 are etched through the pattern area 41, it is beneficial to improve the structural precision of the grating layer 10, obtain a high-precision grating structure 10a, and improve the optical performance of the grating structure 10a.

[0071] Exemplarily, the pattern region 41 may be formed on the photoresist by a grayscale photolithography process, so that the thickness of at least one portion of the pattern region 41 is different from that of other portions.

[0072] Exemplarily, multiple layers of photoresist may be coated on the surface of the isolation layer 30 , and the multiple layers of photoresist are processed layer by layer through a multi-layer photoresist process so that the multiple layers of photoresist form a pattern area 41 , and the thickness of at least one portion of the pattern area 41 is different from that of other portions.

[0073] In some embodiments, etching the positions of the isolation layer 30 and the area to be thinned 11 corresponding to the pattern area 41 includes: etching the positions of the isolation layer 30 and the area to be thinned 11 corresponding to the pattern area 41 by a plasma etching process. It can be understood that the plasma etching process can uniformly etch a variety of materials, improve the preparation efficiency of the grating structure 10a, and ensure the accuracy of the grating layer 10 after etching, ensuring that the optical performance of the grating structure 10a is better.

[0074] For example, Figure 2 As shown in Figure (D), when the thickness of the pattern area 41 is 0 at all locations, the position of the isolation layer 30 corresponding to the pattern area 41 is exposed. When plasma is used to etch the isolation layer 30 and the area to be thinned 11, the plasma can directly etch the isolation layer 30 and the area to be thinned 11 through the pattern area 41.

[0075] For example, Figure 3 As shown in Figure (D), when the thickness of the pattern area 41 is greater than 0, the position of the isolation layer 30 corresponding to the pattern area 41 is still covered by the mask layer 40. When plasma is used to etch the isolation layer 30 and the area to be thinned 11, the plasma can continue to etch the isolation layer 30 and the area to be thinned 11 after etching the mask layer 40.

[0076] It is understandable that when the thickness of at least one pattern region 41 is different, the thickness of the non-pattern region of the mask layer 40 is greater than the maximum etching depth of the grating layer 10 , so as to avoid the influence of plasma on the non-thinning region 12 of the grating layer 10 .

[0077] In an exemplary embodiment, a plasma etching process may be used to remove the mask layer 40 and the isolation layer 30. The mask layer 40 and the isolation layer 30 are etched by using plasma having an etching effect on the mask layer 40 and the isolation layer 30, so that the mask layer 40 and the isolation layer 30 are removed from the grating layer 10.

[0078] In another exemplary embodiment, a solvent that does not dissolve the grating layer 10 may be used to dissolve the isolation layer 30 , so that the mask layer 40 and the isolation layer 30 are separated from the grating layer 10 .

[0079] In some embodiments, the area to be thinned 11 includes at least a first sub-region and a second sub-region, and the maximum value of the etching depth of the first sub-region is different from the maximum value of the etching depth of the second sub-region. It can be understood that the maximum values ​​of the etching depths of the first sub-region and the second sub-region are different, so that the thicknesses of the first sub-region and the second sub-region after etching are different, and the first sub-region and the second sub-region have different light diffraction effects.

[0080] It is worth noting that the first sub-region and the second sub-region may be one or more. For example, when there are multiple first sub-regions, the multiple first sub-regions may be spaced apart from each other.

[0081] Specifically, the area to be thinned 11 includes at least a first sub-region and a second sub-region, and the area to be thinned 11 may also include a third sub-region, a fourth sub-region, and so on, and the area ranges between different sub-regions are different. For example, the first sub-region and the second sub-region may be two independent regions, or the first sub-region and the second sub-region may be two connected regions. The specific adjustment can be made according to the actual situation and is not limited here.

[0082] Exemplarily, in addition to the aforementioned method of making the thickness of the pattern area 41 of the mask layer 40 different at a point corresponding to the first sub-area and at a point corresponding to the second sub-area so that the thicknesses of the first sub-area and the second sub-area of ​​the area to be thinned 11 are different after etching, the first sub-area and the second sub-area can also be etched separately so that the thicknesses of the first sub-area and the second sub-area of ​​the area to be thinned 11 are different after etching.

[0083] Furthermore, the preparation method includes: forming a first isolation layer 30 on the surface of the grating layer 10, forming a first mask layer 40 on the surface of the first isolation layer 30 away from the grating layer 10, the first mask layer 40 is provided with a first groove, etching the first isolation layer 30 and the first sub-region corresponding to the first pattern region, and removing the first mask layer 40 and the first isolation layer 30; and after removing the first mask layer 40 and the first isolation layer 30, forming a second isolation layer 30 on the surface of the grating layer 10, forming a second mask layer 40 on the surface of the second isolation layer 30 away from the grating layer 10, the first mask layer 40 is provided with a second groove, etching the second isolation layer 30 and the second sub-region corresponding to the second pattern region, and removing the second mask layer 40 and the second isolation layer 30. It can be understood that after the etching of the first sub-region is completed, the first isolation layer 30 and the first mask layer 40 are removed, and then the second isolation layer 30 is re-set on the grating layer 10 to achieve etching of the second sub-region, reduce interference with etching preparation and etching work in different sub-regions, ensure the structural accuracy of the grating layer 10, and ensure the optical performance of the grating structure 10a.

[0084] Of course, in other embodiments, when the first sub-region and the second sub-region are independent of each other, different positions on the mask layer 40 on the surface of the grating layer 10 can have pattern regions 41 with different thicknesses. For example, different positions of the mask layer 40 form a third pattern region and a fourth pattern region, the thickness of the third pattern region is less than the thickness of the fourth pattern region, the first sub-region corresponds to the third pattern region, and the second sub-region corresponds to the fourth pattern region. The isolation layer 30, the first sub-region and the second sub-region are etched at the same time, so that the thicknesses of the first sub-region, the second sub-region and the non-thinning area 12 are different after etching.

[0085] The embodiment of the present invention further provides a grating structure, which can be prepared by the preparation method described above. It can be understood that the grating structure prepared by the preparation method described above is less affected by the mask layer during the preparation process, which is conducive to improving the optical performance of the grating structure, and the material range of the mask layer during the preparation process is wider, which is conducive to further optimizing the preparation cost of the grating structure.

[0086] An embodiment of the present invention provides a near-eye display device, and the near-eye display device includes the grating structure described above. The use of this grating structure is beneficial to enhancing the display performance of the near-eye display device, and in the preparation process of the grating structure, the material range of the mask layer is wider, which is beneficial to further optimize the preparation cost of the near-eye display device.

[0087] It should be understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, including these combinations. It should be noted that, in this article, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "including a..." does not exclude the presence of other identical elements in the process, method, article or system including the element.

[0088] The serial numbers of the embodiments of the present invention are only for description and do not represent the advantages and disadvantages of the embodiments. The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for preparing a grating structure, characterized in that: The following steps are involved: forming an isolation layer on a surface of a grating layer, wherein the grating layer has a region to be thinned; forming a mask layer on a surface of the isolation layer away from the grating layer, wherein the mask layer has a pattern region; Etching the isolation layer and the area to be thinned at positions corresponding to the pattern area; The mask layer and the isolation layer are removed.

2. The method for preparing a grating structure according to claim 1, characterized in that: The isolation layer includes at least one inorganic isolation layer.

3. The method for preparing a grating structure according to claim 1, characterized in that: The step of forming an isolation layer on the surface of the grating layer comprises: forming the isolation layer on the surface of the grating layer by a thin film deposition process; or An isolation material is coated on the surface of the grating layer to form the isolation layer.

4. The method for preparing a grating structure according to claim 1, characterized in that: The thickness of the pattern area is the same at all places; or the thickness of the pattern area is different at least at one place.

5. The method for preparing a grating structure according to claim 1, characterized in that: The etching of the isolation layer and the position of the area to be thinned corresponding to the pattern area includes: The mask layer, the isolation layer and the area to be thinned are etched at positions corresponding to the pattern area.

6. The method for preparing a grating structure according to any one of claims 1 to 5, characterized in that: The etching of the isolation layer and the position of the area to be thinned corresponding to the pattern area includes: The isolation layer and the area to be thinned corresponding to the pattern area are etched by a plasma etching process.

7. The method for preparing a grating structure according to any one of claims 1 to 5, characterized in that: The area to be thinned includes at least a first sub-region and a second sub-region, and the maximum value of the etching depth of the first sub-region is different from the maximum value of the etching depth of the second sub-region.

8. The method for preparing a grating structure according to claim 7, characterized in that: The preparation method comprises: forming a first isolation layer on the surface of the grating layer; forming a first mask layer on a surface of the first isolation layer away from the grating layer, wherein the first mask layer is provided with a first pattern region; Etching the first isolation layer and the first sub-region at positions corresponding to the first pattern region; removing the first mask layer and the first isolation layer; forming a second isolation layer on the surface of the grating layer; forming a second mask layer on a surface of the second isolation layer away from the grating layer, wherein the second mask layer is provided with a second pattern region; Etching the second isolation layer and the second sub-region at positions corresponding to the second pattern region; The second mask layer and the second isolation layer are removed.

9. A grating structure, characterized in that: The grating structure is prepared by the preparation method described in any one of claims 1 to 8.

10. A near-eye display device, characterized in that: Comprising the grating structure as claimed in claim 9.

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