Grating, grating preparation method, optical waveguide and near-to-eye display equipment

Abstract

The invention provides a grating, a grating preparation method, an optical waveguide and a near-to-eye display device. The grating comprises a substrate and a diffraction layer. The diffraction layer comprises at least two sub-layers, the sub-layers are stacked on the surface of the substrate, and the sub-layers are prepared from organic matter and / or halide. The grating has a good diffraction effect, the preparation process is simple, and the preparation efficiency and the finished product yield of the grating can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of diffraction gratings, and in particular to a grating, a grating preparation method, an optical waveguide and a near-eye display device. Background Art

[0002] In near-eye display devices, directional propagation of signal light is mostly achieved by setting up a diffraction optical waveguide; the core component of the diffraction optical waveguide is the diffraction grating, but in related technologies, in order to facilitate batch production of diffraction optical waveguides, the same material is used to manufacture surface relief gratings and holographic gratings, which limits the diffraction effect of the grating. In related technologies, surface relief gratings formed by stacking multiple materials can improve the diffraction effect to a certain extent, but such surface relief gratings are mostly prepared by stacking inorganic materials such as glass. Inorganic materials are relatively hard and can basically only be prepared by etching processes. The preparation process is relatively complex, the preparation efficiency is low, and the finished product yield is low. Summary of the invention

[0003] The present application provides a grating, a grating preparation method, an optical waveguide and a near-eye display device, aiming to improve the diffraction effect of the grating and reduce the complexity of grating preparation, so as to improve the preparation efficiency of the grating and the yield of the finished product.

[0004] In a first aspect, the present application provides a grating, the grating comprising:

[0005] substrate;

[0006] The diffraction layer comprises at least two sub-layers, the sub-layers are stacked and arranged on the surface of the substrate, and the sub-layers are made of organic matter and / or halide.

[0007] In a second aspect, the present application further provides a grating preparation method, the grating preparation method comprising:

[0008] providing a substrate;

[0009] Arranging a layer to be prepared on the surface of the substrate, wherein the layer to be prepared comprises at least two stacked sub-layers to be prepared, and the sub-layers to be prepared comprise organic matter and / or halide;

[0010] The layer to be prepared is subjected to an embossing process by an embossing process, and / or the layer to be prepared is subjected to an exposure process by a holographic exposure process to obtain a diffraction layer.

[0011] In a third aspect, the present application further provides an optical waveguide, comprising a waveguide substrate and a grating, wherein the grating is arranged on at least one surface of the waveguide substrate, and the grating is the grating as described in any one of claims 1-8.

[0012] In a fourth aspect, the present application also provides a near-eye display device, comprising the optical waveguide as claimed in claim 12.

[0013] The present application provides a grating, a grating preparation method, an optical waveguide and a near-eye display device. The present application provides a diffraction layer in the grating including at least two sublayers, and each sublayer is prepared from organic matter and / or halides. The grating obtained by stacking multiple sublayers can adjust the energy of an incident light beam and / or the diffraction direction of light based on different sublayers, thereby effectively improving the diffraction effect of the grating. The diffraction layer is prepared from organic matter and / or halides, which can reduce the complexity of the grating preparation process, thereby improving the preparation efficiency and product yield of the grating. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] 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.

[0015] Figure 1 A schematic diagram of a grating provided in an embodiment of the present application;

[0016] Figure 2 A schematic diagram of a grating provided in another embodiment of the present application;

[0017] Figure 3 A schematic diagram of a grating provided in yet another embodiment of the present application;

[0018] Figure 4 A schematic diagram of a grating provided in yet another embodiment of the present application;

[0019] Figure 5 A schematic diagram of a grating provided in another embodiment of the present application;

[0020] Figure 6 A schematic diagram of a two-dimensional grating dot matrix provided in an embodiment of the present application;

[0021] Figure 7 A flowchart of the steps of a grating preparation method provided in one embodiment of the present application;

[0022] Figure 8 A schematic diagram of an optical waveguide provided in one embodiment of the present application;

[0023] Fig. 9 A schematic diagram of a near-eye display device provided in accordance with an embodiment of the present invention.

[0024] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0026] 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 also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0027] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0028] Please refer to Figure 1 and Figure 2 , Figure 1 A schematic diagram of a grating 10 provided in an embodiment of the present application, Figure 2 A schematic diagram of a grating 10 provided in accordance with another embodiment of the present application.

[0029] like Figure 1 As shown, the grating 10 includes a substrate 11 and a diffraction layer 12. The substrate 11 is used to provide mechanical support and fixation for the diffraction layer 12, and the substrate 11 also needs to have certain optical properties, including but not limited to high light transmittance and a flat surface. Specifically, the base layer can be made of materials such as glass or quartz, which is not limited here.

[0030] The diffraction layer 12 includes at least two sublayers, and the multiple sublayers are stacked on the surface of the substrate 11 to diffract the incident light, wherein each sublayer is made of at least one of an organic substance and a halide. It should be noted that the diffraction layer 12 obtained by stacking multiple sublayers can effectively improve the diffraction effect of the grating 10, and the preparation of the sublayers by organic substances and / or halides can reduce the preparation complexity and difficulty of the diffraction layer 12, thereby improving the efficiency and cost-effectiveness of the preparation of the grating 10.

[0031] In the specific implementation process, Figure 1 As shown, the grating 10 is a surface relief grating, wherein the diffraction layer 12 in the surface relief grating includes a plurality of slits that are not parallel to the substrate 11; for example, Figure 2As shown, the grating 10 is a holographic grating, and the diffraction layer 12 in the holographic grating includes a holographic layer. The present application does not limit the type of the grating 10.

[0032] In some embodiments, at least two sublayers include a first sublayer 121 and a second sublayer 122, the first sublayer 121 is disposed on the surface of the substrate 11, and the second sublayer 122 is stacked on the surface of the first sublayer 121; the first sublayer 121 is prepared from the organic matter and / or the halide, and the second sublayer 122 is prepared from the organic matter and / or the halide.

[0033] In a specific implementation process, at least two sublayers include a first sublayer 121 and a second sublayer 122, the first sublayer 121 is arranged on the surface of the substrate 11, and the second sublayer 122 is arranged on the other side surface of the first sublayer 121 away from the substrate 11, so as to realize a stacked arrangement on the substrate 11, and the first sublayer 121 is made of organic matter or halide; the second sublayer 122 is also made of organic matter or halide. It should be noted that the first sublayer 121 and the second sublayer 122 can both be made of organic matter or halide; or the first sublayer 121 is made of organic matter, and the second sublayer 122 is made of halide; or the first sublayer 121 is made of halide, and the second sublayer 122 is made of organic matter, and this application does not limit it.

[0034] In some embodiments, the sub-layer includes at least one of an embossed adhesive layer, a resin coating layer, a liquid crystal layer, and a halide layer.

[0035] In a specific implementation process, the diffraction layer 12 includes at least two sublayers made of different materials, wherein the materials for preparing the sublayers include but are not limited to embossed glue, resin, liquid crystal material and halide material to prepare an embossed glue layer, a resin coating layer, a liquid crystal layer and a halide layer; for example, at least two sublayers include a first sublayer 121 and a second sublayer 122, the first sublayer 121 is a resin coating layer, and the second sublayer 122 is a liquid crystal layer, an embossed glue layer and a halide layer; and in the case where at least two sublayers include a first sublayer 121, a second sublayer 122 and a third sublayer, two of the sublayers can be prepared from the same material, and the sublayers prepared from different materials are arranged between the sublayers prepared from the same material, For example, the preparation material of the first sublayer 121 is the same as that of the third sublayer, while the second sublayer 122 and the first sublayer 121 are made of different materials; the first sublayer 121 is arranged on the surface of the substrate 11, the second sublayer 122 is arranged on the surface of the first sublayer 121, and the third sublayer is arranged on the surface of the second sublayer 122; in other embodiments, the first sublayer 121, the second sublayer 122 and the third sublayer are all made of different materials, for example, the first sublayer 121 is a resin coating layer, the second sublayer 122 is a liquid crystal layer, and the third sublayer is an embossed adhesive layer; the specific preparation material of each sublayer is not limited here, nor is the specific setting position of the sublayers prepared from various materials limited. It should be understood that the same sublayer is made of the same material to reduce the complexity of the preparation process.

[0036] In some embodiments, the embossed adhesive layer includes at least one of acrylate, epoxy resin and metal oxide; and / or the resin coating layer includes at least one of a glass cellulose coating layer, a fluorine polymer resin coating layer and a high-grade resin film layer; and / or the liquid crystal layer includes a disc-shaped liquid crystal and / or a rod-shaped liquid crystal; and / or the halide layer includes a metal halide and / or a non-metal halide.

[0037] Exemplarily, the materials for preparing the above-mentioned embossed adhesive layer include but are not limited to acrylates, epoxy resins and metal oxides; the materials for preparing the resin coating layer include but are not limited to glass cellulose coatings, fluorine polymer resin coatings and high-performance synthetic resins; the materials for preparing the liquid crystal layer include but are not limited to discotic liquid crystals and rod-shaped liquid crystals, wherein the discotic liquid crystals and rod-shaped liquid crystals can usually present a phase column or a cholesteric phase; the materials for preparing the halide layer include metal halides and non-metallic halides. It should be understood that when the diffraction layer 12 is prepared by using the above-mentioned materials, there is no need to prepare the diffraction layer 12 by an etching process, but the diffraction layer 12 is prepared by an embossing process and / or a holographic exposure process, thereby effectively avoiding the uncertainty and difficulty brought by the etching process, thereby reducing the complexity of the preparation, and further improving the preparation efficiency and the yield of the finished product.

[0038] In some embodiments, the sub-layers form a relief structure layer and / or a holographic layer.

[0039] Exemplarily, the sub-layer can form a relief structure layer, so that the diffraction layer 12 has multiple slits, and the direction of the slits is not parallel to the direction in which the substrate 11 is set, so that the cross-section of the relief structure layer can be one of a straight groove envelope, a bevel tooth envelope, a blazing envelope, a step envelope and a curved surface envelope.

[0040] Exemplarily, the sub-layers can also form a holographic layer, wherein the formed holographic layer can diffract incident light to obtain a holographic grating.

[0041] It should be noted that the above-mentioned relief structure layer or holographic layer can be separately arranged on the substrate 11 to obtain a surface relief grating or a holographic grating; and the relief structure layer and the holographic layer can also be arranged on the same substrate 11 so that the grating 10 includes the relief structure layer and the holographic layer.

[0042] In some embodiments, the first sublayer 121 forms the holographic layer, and the second sublayer 122 forms the relief structure layer or the holographic layer; or, the first sublayer 121 and the second sublayer 122 both form the relief structure layer, and the projection of the slit of the first sublayer 121 on the substrate 11 overlaps with the projection of the slit of the second sublayer 122 on the substrate 11.

[0043] Exemplarily, at least one sublayer includes a first sublayer 121 and a second sublayer 122 , and the first sublayer 121 is disposed on the surface of the substrate 11 , and the second sublayer 122 is disposed on the first sublayer 121 away from the surface of the substrate 11 .

[0044] See also Figure 3 , Figure 3 FIG. 1 is a schematic diagram of a grating 10 provided in another embodiment of the present application. Figure 3 As shown, the first sub-layer 121 is a holographic layer, and the second sub-layer 122 is a relief structure layer.

[0045] In other embodiments, the first sublayer 121 is a holographic layer, and the second sublayer 122 may also be a holographic layer; in yet other embodiments, if the first sublayer 121 is a relief structure layer, the second sublayer 122 is also a relief structure layer, and the slits of the relief structure layer in the first sublayer 121 and the slits of the relief structure layer in the second sublayer 122 are the same in size and position, that is, Figure 1 The grating 10 is shown.

[0046] In other embodiments, when at least one sublayer includes a first sublayer 121, a second sublayer 122, and a third sublayer, the first sublayer 121, the second sublayer 122, and the third sublayer are stacked in sequence on the substrate 11; if the first sublayer 121 is formed as a holographic layer, the second sublayer 122 is formed as a relief structure layer or a holographic layer, and if the second sublayer 122 is a holographic layer, the third sublayer is a relief structure layer or a holographic layer; and if the second sublayer 122 is a relief structure layer, the third sublayer is also a relief structure layer. It should be understood that if a sublayer is formed as a relief structure layer, the sublayer further away from the substrate 11 than the sublayer is formed as a relief structure layer; the present application does not limit the number of sublayers and the specific sublayers set as relief structure layers or holographic layers.

[0047] See also Figure 4 , Figure 4 A schematic diagram of a grating 10 provided in yet another embodiment of the present application.

[0048] In some embodiments, when at least one of the sub-layers forms a relief structure layer, the grating 10 further includes a filling layer 13, and the filling layer 13 is used to fill the slits in the relief structure layer.

[0049] Exemplarily, the refractive index of the filling layer 13 is lower than that of the sub-layer, and the filling layer 13 also has a low absorption property to avoid excessive loss of light energy of the incident light.

[0050] Please continue reading Figure 4 In some embodiments, the thickness of the filling layer 13 is equal to the thickness of the relief structure layer.

[0051] See also Figure 5 , Figure 5 A schematic diagram of a grating 10 provided in accordance with another embodiment of the present application.

[0052] like Figure 5 As shown, in some other embodiments, the thickness of the filling layer 13 is greater than the thickness of the relief structure layer.

[0053] Specifically, if the first sublayer 121 and the second sublayer 122 both form a relief structure layer, the thickness of the filling layer 13 is greater than or equal to the sum of the thicknesses of the first sublayer 121 and the second sublayer 122; and if the first sublayer 121 forms a holographic layer and the second sublayer 122 forms a relief structure layer, the thickness of the filling layer 13 is greater than or equal to the thickness of the second sublayer 122, wherein the thickness of the first sublayer 121 and the thickness of the second sublayer 122 may be the same or different, and this application does not limit this.

[0054] By providing the filling layer 13, the degree of freedom in designing the grating 10 can be increased, the grating 10 can be made less prone to deformation, and the thickness and / or shape fluctuation of the optical element provided on the surface of the relief structure layer can be reduced.

[0055] In some embodiments, the grating 10 includes sub-partitions, and the grating vectors of different sub-partitions are the same. When a relief structure layer is formed in the sub-layer, at least one of the morphology, groove depth and refractive index in different areas of the same sub-layer may be different; when a holographic layer is formed in the sub-layer, the inclination angle may also be different, and a relief structure layer and / or a holographic layer is formed in part of the same sub-layer, while the relief structure layer and the holographic layer may not be formed in the remaining part, and the remaining part may only be able to transmit light. The present application does not limit whether sub-partitions are included on the same sub-layer, and the specific settings of the sub-partitions.

[0056] In a specific implementation process, if the grating 10 is not provided with a filling layer 13, and each sublayer is a relief structure layer, the grating 10 is a surface relief grating, and the refractive index of each sublayer is between 1.2 and 3.0; and if each sublayer is a holographic layer, the grating 10 is a holographic grating, and the maximum difference between the high refractive index part and the low refractive index part is between 0.02 and 0.8; and the refractive index of each sublayer can be set according to actual conditions, for example, the grating 10 includes multiple sublayers, and the sublayer with the highest refractive index is set on the surface of the substrate 11; or the sublayer farthest from the substrate 11 is the sublayer with the highest refractive index; or the sublayer with the highest refractive index is set in the middle sublayer. The present application does not limit the refractive index of each sublayer and the refractive index relationship between the sublayers.

[0057] In a specific implementation process, the refractive index of the filling layer 13 is between 1.0 and 2.0.

[0058] By means of the grating 10 provided above, a plurality of sub-layers are stacked and arranged on the surface of the substrate 11, so that the energy and / or diffraction direction of the incident light beam can be re-modulated to achieve the purpose of less energy loss of the diffracted light beam, thereby improving the diffraction effect of the grating 10, and the diffraction layer 12 is prepared by organic matter and / or halide, which can reduce the complexity of the preparation process of the grating 10, so as to improve the preparation efficiency of the grating 10 and the yield rate of the finished product.

[0059] See also Figure 6 , Figure 6 A schematic diagram of a two-dimensional grating matrix provided in an embodiment of the present application.

[0060] In a specific implementation process, the grating 10 can be a one-dimensional grating, or a Figure 6The two-dimensional grating shown in the figure, wherein the line segments p1 and p2 in the figure are schematic line segments, p1 is used to indicate the direction of one grating period of the two-dimensional grating, and p2 is used to indicate the direction of another grating period of the two-dimensional grating. It should be noted that the dots in the figure are only schematic examples of microstructures, and the microstructures include but are not limited to regular shapes such as ellipses and squares, or irregular shapes, which are not limited in this application. Specifically, the period in each direction of the two-dimensional grating is between 100nm and 600nm, and the thickness of each sublayer in the diffraction layer 12 is between 10nm and 2um; the duty cycle is between 0.05 and 0.95, and the vector direction can be any angle between 0° and 360°. And when the grating 10 is a two-dimensional grating, the minimum angle between different grating periods can be 20° to 90°, and this application does not limit the number of directions of the grating period.

[0061] See also Figure 7 , Figure 7 A flowchart of the steps of a grating preparation method provided in one embodiment of the present application.

[0062] The present application also provides a grating preparation method, wherein the grating provided in any of the above embodiments can be prepared by the grating preparation method. Figure 7 As shown, the grating preparation method includes steps S101 to S103.

[0063] Step S101: providing a substrate.

[0064] Exemplarily, a substrate is provided, which is used to provide mechanical support and fixing points for other layers, wherein the substrate can be made of quartz or glass, and the substrate has good optical properties, including but not limited to high light transmittance and low light absorption.

[0065] Step S102 : arranging a layer to be prepared on the surface of the substrate, wherein the layer to be prepared includes at least two stacked sub-layers to be prepared, and the sub-layers to be prepared include organic matter and / or halides.

[0066] Exemplarily, a layer to be prepared is disposed on the surface of the substrate. Specifically, the layer to be prepared includes at least two stacked sub-layers to be prepared, and each sub-layer to be prepared is made of organic matter and / or halide.

[0067] Step S103: performing an embossing process on the layer to be prepared by an embossing process, and / or performing an exposure process on the layer to be prepared by a holographic exposure process, to obtain a diffraction layer.

[0068] Exemplarily, after completing the setting of the layer to be prepared, the layer to be prepared is subjected to embossing and / or holographic exposure processing to obtain a diffraction layer. It should be understood that the obtained diffraction layer includes at least two stacked sub-layers to enhance the diffraction effect of the grating, and in the preparation process of the grating, there is no need to utilize an etching process, which can reduce the complexity of the grating preparation process, thereby improving the grating preparation efficiency and the finished product yield.

[0069] In some embodiments, the sub-layer to be prepared is provided by coating and / or plating stacking.

[0070] In a specific implementation process, the first layer of the sublayer to be prepared is set on the surface of the substrate by coating or plating, and the second layer of the sublayer to be prepared is set on the surface of the first layer of the sublayer to be prepared away from the substrate by coating or plating, and so on, until the setting of all the sublayers to be prepared is completed. It should be noted that those skilled in the art can select the corresponding method to set the sublayers to be prepared according to the actual setting requirements. For example, in the process of setting a layer to be prepared, all the sublayers to be prepared are set by coating, or all the sublayers to be prepared are set by plating, or some of the sublayers to be prepared are set by coating, and the rest of the sublayers to be prepared are set by plating, and this application does not limit it.

[0071] In some embodiments, the coating includes at least one of the following: Czochralski method, flow coating, blade coating and spin coating; the coating includes at least one of the following: sputtering, evaporation, deposition and sol-gel.

[0072] Exemplarily, the layer to be prepared is coated or plated by the above-provided method, thereby completing the setting of the layer to be prepared. In the specific implementation process, before setting multiple sub-layers to be prepared, steps such as baking, vacuuming, and low-dose exposure pre-curing are also included; for example, after a layer of material of the sub-layer to be prepared is set by spin coating, the spin-coated sub-layer to be prepared is cured by one of baking, vacuuming, and low-dose exposure pre-curing. It should be understood that the curing methods of different sub-layers to be prepared may be different. For example, the curing method of the first sub-layer to be prepared is baking, and the curing method of the second sub-layer to be prepared may also be baking, or vacuuming, or low-dose exposure pre-curing, and this application does not limit it.

[0073] In some embodiments, at least one of the sub-layers to be prepared is embossed by a single embossing process to form a relief structure layer; and / or, at least one of the sub-layers to be prepared is exposed by a single holographic exposure process to form a holographic layer.

[0074] Illustratively, since the materials of the sub-layers to be prepared are organic substances that are softer than inorganic materials, or halides that are easier to handle, when preparing a relief structure, multiple sub-layers to be prepared can be embossed to form a relief structure layer without the need for multiple embossings; and when performing a holographic exposure process, multiple sub-layers to be prepared can also form a holographic layer through a single exposure without the need for multiple exposures, thereby simplifying the grating preparation process and improving the grating preparation efficiency.

[0075] See also Figure 8 , Figure 8 A schematic diagram of an optical waveguide provided in accordance with an embodiment of the present application.

[0076] The present application also provides an optical waveguide 100 , which includes a grating 10 and a waveguide substrate 20 . The grating 10 is disposed on at least one surface of the waveguide substrate 20 . The grating 10 may refer to any of the embodiments provided above.

[0077] In a specific implementation process, if the optical waveguide 100 is set on a near-eye display device, the optical waveguide 100 can directionally transmit the signal light emitted from the optical machine in the near-eye display device to the eyes of the user wearing the near-eye display device, wherein the optical waveguide 100 includes a waveguide substrate 20 and at least one grating 10, the grating 10 is used to couple the signal emitted by the optical machine into the waveguide substrate 20, so that the coupled light propagates in the waveguide substrate 20, and the grating 10 is also used to couple the light propagating in the waveguide substrate 20 to the human eye to achieve display; specifically, the grating 10 is on the waveguide substrate 20 It is configured as an in-coupling grating and an out-coupling grating, and the in-coupling grating and the out-coupling grating can be arranged on the same surface of the waveguide substrate 20, or respectively arranged on two opposite surfaces of the waveguide substrate 20, and the in-coupling grating and the out-coupling grating can both be arranged on the side of the waveguide substrate 20 close to the human eye; or both are arranged on the side away from the human eye; or the in-coupling grating is arranged on the side of the waveguide substrate 20 close to the human eye, and the out-coupling grating is arranged on the side away from the human eye; or the in-coupling grating is arranged on the side of the waveguide substrate 20 away from the human eye, and the out-coupling grating is arranged on the side close to the human eye, and the present application does not make any limitation.

[0078] In one embodiment, at least one first film layer is arranged between the grating 10 and the waveguide substrate 20; and / or at least one second film layer is arranged on the surface of the grating 10 away from the waveguide substrate 20, wherein the first film layer and the second film layer are both made of dielectric material or metal material, and the present application does not limit the setting position, material and number of the film layers.

[0079] See also Fig. 9 , Fig. 9 A schematic diagram of a near-eye display device provided in accordance with an embodiment of the present invention.

[0080] As shown in the figure, the present application also provides a near-eye display device, which includes at least an optical machine and an optical waveguide as provided in the above embodiment, wherein the optical waveguide can transmit the signal light emitted from the optical machine in a direction to the eyes of a user wearing the near-eye display device, so that the user can see the corresponding image, animated picture or video.

[0081] It should be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0082] It should also be understood that the term "and / or" used in the specification of this application 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 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.

[0083] The serial numbers of the embodiments of the present application are for description only and do not represent the advantages and disadvantages of the embodiments. The above description is only a specific implementation mode of the present application, but the protection scope of the present application 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 in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A grating, characterized in that: The grating comprises: substrate; The diffraction layer comprises at least two sub-layers, the sub-layers are stacked and arranged on the surface of the substrate, and the sub-layers are made of organic matter and / or halide.

2. The grating according to claim 1, characterized in that The sub-layer includes at least one of an embossed adhesive layer, a resin coating layer, a liquid crystal layer and a halide layer.

3. The grating according to claim 2, characterized in that The embossed adhesive layer comprises at least one of acrylate, epoxy resin and metal oxide; and / or The resin coating layer includes at least one of a glass cellulose coating layer, a fluorine polymer resin coating layer and a high-grade resin film layer; and / or The liquid crystal layer includes discotic liquid crystal and / or rod-shaped liquid crystal; and / or The halide layer includes metal halide and / or non-metal halide.

4. The grating according to claim 1, characterized in that The sub-layers form a relief structure layer and / or a holographic layer.

5. The grating according to any one of claims 1 to 4, characterized in that The at least two sublayers include a first sublayer and a second sublayer, the first sublayer is arranged on the surface of the substrate, and the second sublayer is stacked and arranged on the surface of the first sublayer; the first sublayer is prepared from the organic matter or the halide, and the second sublayer is prepared from the organic matter or the halide.

6. The grating according to claim 5, characterized in that The first sublayer forms the holographic layer, and the second sublayer forms the relief structure layer or the holographic layer; or, the first sublayer and the second sublayer both form the relief structure layer, and the projection of the slit of the first sublayer on the substrate overlaps with the projection of the slit of the second sublayer on the substrate.

7. The grating according to any one of claims 1 to 4, characterized in that In the case where at least one of the sub-layers forms a relief structure layer, the grating further comprises a filling layer, and the filling layer is used to fill the slits in the relief structure layer.

8. The grating according to claim 7, characterized in that The thickness of the filling layer is greater than or equal to the thickness of the relief structure layer.

9. A grating preparation method, characterized in that: The grating preparation method comprises: providing a substrate; Arranging a layer to be prepared on the surface of the substrate, wherein the layer to be prepared comprises at least two stacked sub-layers to be prepared, and the sub-layers to be prepared comprise organic matter and / or halide; The layer to be prepared is subjected to an embossing process by an embossing process, and / or the layer to be prepared is subjected to an exposure process by a holographic exposure process to obtain a diffraction layer.

10. The grating preparation method according to claim 9, characterized in that: The sub-layer to be prepared is arranged by coating and / or plating stack.

11. The grating preparation method according to claim 9, characterized in that: The coating includes at least one of the following: pulling method, flow coating, blade coating and spin coating; the coating includes at least one of the following: sputtering, evaporation, deposition and sol-gel.

12. The grating preparation method according to any one of claims 9 to 11, characterized in that: At least one of the sub-layers to be prepared is subjected to embossing treatment by a single embossing to form a relief structure layer; and / or at least one of the sub-layers to be prepared is subjected to exposure treatment by a single holographic exposure to form a holographic layer.

13. An optical waveguide, characterized in that: The optical waveguide comprises a waveguide substrate and a grating, wherein the grating is arranged on at least one surface of the waveguide substrate, and the grating is the grating according to any one of claims 1 to 8.

14. A near-eye display device, characterized in that: The near-eye display device comprises the optical waveguide of claim 13.

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