Control assembly and method for preparing multi-layer optical gradient structure

Abstract

The invention discloses a control assembly and method for preparing a multilayer optical gradient structure, and the method comprises the steps: providing a substrate which comprises one or more grating structure regions; providing at least two target source materials, and arranging the target source materials above the substrate; providing a control assembly, placing the control assembly between the target source material and the substrate, and attaching the control assembly to the surface of the substrate; at least two material layers are formed on any area of the grating structure area by adjusting the positions of the target source material relative to the first through hole and the second through hole, and the thickness of each material layer is gradually reduced in the target direction; the target direction is a direction in which a first through hole used for forming the material layer points to a second through hole used for forming the material layer. Therefore, the continuous thickness change of the multi-layer optical gradient structure can be accurately controlled.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a control component and method for preparing a multi-layer optical gradient structure. Background Art

[0002] As one of the important optical components in the field of augmented reality technology, diffractive waveguides have a large eye movement range, a compact size, and good mass production. In order to achieve uniform field of view, uniform color, and efficient optical transmission, the industry is constantly working to improve the design and manufacturing process of diffractive waveguides. In particular, how to efficiently produce diffractive waveguides during the manufacturing process has become a hot topic of research.

[0003] At the same time, how to optimize the display appearance of these structures while ensuring the diffraction efficiency of the diffractive optical waveguides remains a problem that needs to be solved continuously. Summary of the invention

[0004] The technical problem solved by the present invention is to provide a control component and method for preparing a multilayer optical gradient structure, which solves the technical problem of ensuring the diffraction efficiency of the optical gradient structure while optimizing the optical gradient structure to achieve highly continuous changes.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a control component for preparing a multilayer optical gradient structure, wherein the control component comprises: a first control plate and a second control plate with a preset spacing; the first control plate comprises at least two first through holes, the second control plate comprises at least one second through hole, and the center lines of at least two of the first through holes and at least one of the second through holes do not overlap; the control component is used to deposit the multilayer optical gradient structure in the second through hole, wherein the multilayer optical gradient structure comprises at least two material layers, and the thickness of each material layer gradually decreases along a target direction, and the target direction is the direction from the first through hole used to form the material layer to the second through hole used to form the material layer.

[0006] Optionally, the material layer is used to form a turning grating and / or an outcoupling grating of a diffraction optical waveguide, and the depth of the turning grating and / or the outcoupling grating gradually increases along the direction of light transmission.

[0007] Optionally, the multilayer optical gradient structure a Layer material thickness The calculation formula is defined as: in, For the a Layer Material The material density of the layer, a Take a positive integer, h is the distance from the center of the target source material to the substrate; For the deposition a Coordinates of multi-layer gradient deposition structures when layers of materials are deposited The thickness of H is the height between the first control board and the substrate, m x1 In the first through hole region x The left critical coordinate value of the axis, m x2 In the first through hole region x The right critical coordinate value of the axis; m y1 is the critical coordinate value on the left side of the y-axis in the first through-hole region, m y2 is the critical coordinate value on the right side of the y-axis in the first through hole area; a x , a y Respectively a The horizontal and vertical coordinate values ​​of any point in the layer from the coordinate center; For the a The integral of any point on the target source material outlet of the layer material layer along the center of the target source material; For the a The control component is used to control the deposition rate of the layer material layer; and the control component is arranged on the surface of the substrate when preparing the multi-layer optical gradient structure.

[0008] Optionally, the second through hole has a first side and a second side relative to each other along the surface of the second control board, and at least two of the first through holes are respectively located on the first side and the second side, and based on the first through holes on the first side and the first through holes on the second side, two material layers with opposite thickness gradient trends are formed respectively.

[0009] Optionally, the refractive indices of two adjacent material layers are different.

[0010] Optionally, the second control plate includes two second through holes, one of which corresponds to a turning grating structure region, and the other second through hole corresponds to a coupling-out grating structure region, and the material layers corresponding to the turning grating structure and the coupling-out grating structure are formed simultaneously in the two second through holes.

[0011] Correspondingly, the technical solution of the present invention also provides a method for preparing a multilayer optical gradient structure, comprising: providing a substrate, the substrate comprising one or more grating structure regions; providing at least two target source materials, arranged above the substrate; providing a control component, and placing the control component between the target source material and the substrate and placed in contact with the surface of the substrate; forming at least two material layers on any area of ​​the grating structure region by adjusting the position of the target source material relative to the first through hole and the second through hole, and the thickness of each material layer gradually decreases along a target direction, and the target direction is the direction in which the first through hole used to form the material layer points to the second through hole used to form the material layer.

[0012] Optionally, the relative position of the target source material with respect to the first through hole and the second through hole satisfies a preset condition, and the preset condition includes:

[0013] in, a x1 , a y1 They respectively represent the critical coordinate values ​​of the left boundary in the activity range of the target source material; a x2 , a y2 They respectively represent the critical coordinate values ​​of the right boundary of the target source material's activity range; H is the distance between the first control plate and the substrate; h is the distance from the center of the target source material to the substrate surface; m x1 is the critical coordinate value on the left side of the x-axis in the first through-hole region, m x2 In the first through hole region x The right critical coordinate value of the axis; m y1 is the critical coordinate value on the left side of the y-axis in the first through-hole region, m y2 is the critical coordinate value on the right side of the y-axis in the first through hole area; u x1 For the second through hole region x The left critical coordinate value of the axis, u y1 is the critical coordinate value on the left side of the y-axis in the second through-hole region; u x2 is the critical coordinate value on the right side of the y-axis in the second through-hole region, u y2is the critical coordinate value on the right side of the y-axis in the second through hole area.

[0014] Optionally, the grating structure region on the surface of the substrate has a grating structure, and the material layer is formed on the surface of the grating structure away from the substrate; or, the substrate has a grating structure in the grating structure region, the substrate and the grating structure surface in the substrate are flat, and the at least two material layers are formed in the grating structure region to form a multi-layer optical gradient grating structure on the grating structure region.

[0015] Correspondingly, the technical solution of the present invention also provides a method for preparing a multilayer optical gradient structure, comprising: providing a substrate, the substrate comprising a grating structure region; providing at least two target source materials, which are arranged above the substrate; providing a control component, and placing it between the target source material and the substrate and attached to the surface of the substrate; forming a first material layer on the grating structure region, and forming a first grating structure based on the first material layer, forming a second material layer on the surface of the first grating structure, and forming a second grating structure based on the second material layer, and continuing to form a third material layer on the second grating structure until the multilayer optical gradient structure is obtained.

[0016] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects: The control component in the technical solution includes a first control plate and a second control plate, so as to construct an optical gradient structure in the second through hole area in the second control plate. This optical gradient structure includes at least two layers of material, and the thickness of each material layer gradually decreases along the target direction, and the target direction is the direction in which the first through hole used to form the material layer points to the second through hole used to form the material layer, forming a stacked optical structure, and the refractive index of each layer of material is different. By controlling the control component, the thickness changes of these multilayer materials in different areas can be accurately controlled, thereby creating an optical gradient structure with gradually changing thickness and different refractive indices of adjacent layers to achieve the expected optical efficiency. First, it can adjust the diffraction efficiency of the optical gradient structure according to the needs of different positions, so as to improve the uniformity of the display and thus improve the overall display effect. Secondly, this design can also optimize the appearance of the optical gradient structure. Since the thickness changes continuously, the problem of sudden thickness changes is avoided, which not only improves the dimensional accuracy of the structure, but also improves the visual effect.

[0017] The method for forming an optical gradient structure of the technical solution of the present invention is to arrange the above-mentioned control component between the target source material and the substrate, the second through hole corresponds to the grating structure area of ​​the optical gradient structure area, the first through hole corresponds to the target source material, and the relative position and sputtering process of the target source material, the first through hole and the second through hole are controlled, so that at least two material layers can be formed on any area of ​​the grating structure area, and the refractive indexes of the two adjacent layers of materials are different, and the display appearance of the optical gradient structure can be accurately controlled, especially in different optical gradient structure areas. The grating structure area is not prone to sudden changes in stripes, so that the thickness of the grating structure area in different optical gradient structure areas is continuously gradient, thereby improving the display appearance of the formed optical gradient structure and modulating the diffraction efficiency of the optical gradient structure at different positions; and further, based on this method, a grating structure in a diffraction optical waveguide is formed to form a grating structure with a continuous gradient in depth, different grating structures have different depths, and the gradient trends of the multiple material layers are opposite, so as to achieve the deposition of materials with different refractive indices. On the one hand, the method modulates the diffraction efficiency of the prepared grating structure at different positions, and selects the refractive index of the deposited material and the refractive index at different positions based on the diffraction efficiency requirement, so that the grating structure has the selected refractive index at different positions, such as the defined continuously gradient diffraction efficiency, thereby improving the display uniformity of the diffraction optical waveguide and improving the display effect of the waveguide; on the other hand, based on the diffraction optical waveguide obtained in this way, different grating structures have continuously gradient depths at different positions, which is different from the existing partition structure in display appearance, so as to achieve a smooth transition of grating areas with different diffraction efficiencies, thereby preventing the visual difference caused by the sudden change of thickness at different positions, and visually obtaining a better appearance effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 and Figure 2 is a schematic structural diagram of a control component for preparing a multi-layer optical gradient structure in one embodiment of the present invention; Figures 3 to 12 is a structural schematic diagram of a process for preparing a multilayer optical gradient structure in an embodiment of the present invention; Fig.13 and Fig.14 is a schematic structural diagram of a control assembly for preparing a multi-layer optical gradient structure in another embodiment of the present invention; Fig.15 and Fig.16 is a structural schematic diagram of a process for preparing a multilayer optical gradient structure in another embodiment of the present invention; Figures 17 to 19 is a schematic structural diagram of a control assembly for preparing a multi-layer optical gradient structure in another embodiment of the present invention; Fig. 20 and Fig.21It is a structural schematic diagram of the preparation process of a multilayer optical gradient structure in another embodiment of the present invention. DETAILED DESCRIPTION

[0019] As described in the background art, how to optimize the optical gradient structure to achieve highly continuous changes while ensuring the diffraction efficiency of the optical gradient structure is a problem that needs to be solved continuously.

[0020] Specifically, in the field of micro-nano optical gradient structure design, in some cases, for specific optical elements that need to adjust performance parameters by thickness changes, it is a technical challenge to accurately achieve continuous gradient thickness. The thickness variation of such structures is usually at the level of tens of nanometers, which is particularly critical for fine control at the nanometer level because it is directly related to the functional realization of optical elements and how to form micro-nano structures with continuously changing thickness. For example, in diffraction optical waveguide technology, the depth gradient modulation of the grating structure is crucial to adjust the diffraction efficiency distribution.

[0021] In addition, when forming an optical gradient structure with a continuously changing thickness, it is easy to form abrupt stripes when the thickness changes gradually between different gradient areas. The abrupt stripes are the locations where the thickness of the optical gradient structure changes suddenly. The abrupt stripes will affect the appearance of the product formed by the optical gradient structure and are not easily accepted by consumers visually. Therefore, it is necessary to improve the generation of abrupt stripes and accurately control the continuous change of the thickness of the optical gradient structure. Further, for example, the grating structure in the diffraction optical waveguide needs to realize continuous gradual modulation of the grating depth to modulate the visibility of the grating structure in the diffraction optical waveguide.

[0022] In order to solve the above problems, an embodiment of the present invention provides a control component and method for preparing a multi-layer optical gradient structure, by arranging the above-mentioned deposition auxiliary structure between the target source material and the substrate, the second through hole corresponds to the grating structure area of ​​the optical gradient structure area, the first through hole corresponds to the target source material, and the relative position and sputtering process of the target source material, the first through hole and the second through hole are controlled, so that at least two material layers can be formed on any area of ​​the grating structure area, and the thickness of each material layer gradually decreases along the target direction, and the target direction is the direction in which the first through hole used to form the material layer points to the second through hole used to form the material layer, so that the display appearance of the optical gradient structure can be accurately controlled, especially in different optical gradient structure areas. The grating structure area thickness of the grating structure area is continuously gradient, so as to improve the display appearance of the formed optical gradient structure and modulate the diffraction efficiency of the optical gradient structure at different positions; and further, based on this method, a grating structure in a diffraction optical waveguide is formed to form a grating structure with a continuous gradient in depth, and different grating structures have different depths.

[0023] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0024] Figure 1 and Figure 2 It is a schematic diagram of the structure of a control component for preparing a multi-layer optical gradient structure in one embodiment of the present invention.

[0025] Please refer to Figure 1 and Figure 2 , Figure 1 for Figure 2 A top view of Figure 2 for Figure 1 A schematic structural diagram along the section line BB1, wherein the control assembly for preparing a multilayer optical gradient structure comprises: a first control plate 101 and a second control plate 102 having a preset spacing; the first control plate 101 comprises at least two first through holes, the second control plate 102 comprises at least one second through hole 105, and the center lines of at least two of the first through holes and at least one of the second through holes 105 do not overlap; The control component is used to deposit an optical gradient structure in the second through hole 105, and the optical gradient structure includes at least two material layers, and the thickness of each material layer gradually decreases along a target direction, and the target direction is the direction from the first through hole used to form the material layer to the second through hole 105 used to form the material layer. When depositing to form the material layer, the material passes through the first through hole and the second through hole 105 in sequence.

[0026] The number of the first through holes is greater than the number of the second through holes 105. The number and positions of the first through holes are set according to the number of material layers to be formed, and the number and positions of the second through holes are set according to the area where the material layer is to be formed.

[0027] In this embodiment, the number of the first through holes is 2; the number of the second through hole 105 is 1.

[0028] In other embodiments, the number of the first through holes is 3 or more, and the number of the second through holes is two or more.

[0029] In other embodiments, when the second control plate includes two second through holes, one of the second through holes corresponds to a turning grating structure region, and the other second through hole corresponds to a coupling-out grating structure region, and the material layers corresponding to the turning grating structure and the coupling-out grating structure are formed simultaneously in the two second through holes.

[0030] In this embodiment, the two first through holes are marked as 1041 and 1042, respectively, and the two first through holes marked as 1041 and 1042 are arranged in a row or a column, and the projection range of each first through hole projected on the second control board 102 partially overlaps with the projection range of the second through hole 105 projected on the second control board 102. That is, the second through hole 105 is arranged at a position between the two first through holes 1041 and 1042 to ensure that the projection of each first through hole on the second control board 102 can overlap with a part of the second through hole 105.

[0031] In this embodiment, the diameters and areas of the two first through holes may be the same or different.

[0032] In this embodiment, the two first through holes marked as 1041 and 1042 have first center lines L11 and L12 respectively, and the distances between the center line L2 of the second through hole 105 and the first center lines L11 and L12 are the same.

[0033] In this embodiment, the control component also includes: a connecting portion 103, wherein the connecting portion 103 connects the first control board 101 and the second control board 102, the first control board 101 and the second control board 102 are connected through the connecting portion 103 to form an integrated structure, and the second control board 102 is bonded to the substrate.

[0034] In other embodiments, the control assembly may not include the connecting portion, the first control board and the second control board are independently formed on a substrate, and the second control board is in contact with the substrate.

[0035] The above-mentioned two embodiments of the connection methods of the control components are all within the protection scope of the present invention. As long as they do not deviate from the purpose of the present invention, that is, to achieve a material layer with a continuously gradient thickness, no limitation is made on the connection method of the control components.

[0036] In this embodiment, the projection range of the first through hole projected onto the second control board 102 partially overlaps with the range of the second through hole 105 , and the projection range of the first through hole projected onto the second control board 102 overlaps with the range of the second through hole 105 .

[0037] In other embodiments, a projection range of the first through hole projected onto the second control plate does not overlap with a range of the second through hole.

[0038] The center lines of at least two of the first through holes and at least one of the second through holes 105 do not overlap, including: the center line of each of the first through holes and each of the second through holes 105 do not overlap; or, the center line of the entirety of at least two of the first through holes does not overlap with the center line of the entirety of at least one of the second through holes 105.

[0039] In this embodiment, the center line of the first through hole does not coincide with the center line L2 of the second through hole 105 , that is, the center line of any first through hole does not coincide with the center line L2 of any second through hole 105 , so as to accurately control the process of forming the material layer with continuous gradient thickness in the second through hole 105 .

[0040] In this embodiment, the first control board 101 and the second control board 102 are arranged in parallel to form a material layer with a preset thickness variation in the second through hole 105 .

[0041] The first control board 101 and the second control board 102 are arranged in parallel, which can reduce the risk of interference between the control component and the material source or the machine chamber, and facilitate the adjustment of the thickness variation trend of the material formed in the second through hole 105.

[0042] The shape of the first through hole includes circle, ellipse, rectangle, trapezoid or polygon, and the number of sides of the polygon is greater than or equal to 5.

[0043] In this embodiment, the shape of the first through hole includes a circle.

[0044] The second through hole 105 has a shape of a rectangle, a trapezoid or a polygon, and the number of sides of the polygon is greater than or equal to 5.

[0045] In one embodiment, the shape of the first through hole is the same as the shape of the second through hole 105. The shape of the first through hole and the shape of the second through hole 105 include a rectangle, a trapezoid or a polygon.

[0046] In another embodiment, the shape of the first through hole is different from the shape of the second through hole 105 .

[0047] The material of the control component includes metal or metal alloy, the metal alloy includes stainless steel and iron-nickel alloy, and the metal includes iron, aluminum or titanium.

[0048] The control component includes a first control plate and a second control plate, so as to construct an optical gradient structure in the second through hole area of ​​the second control plate. This optical gradient structure includes at least two layers of material, the thickness of each layer can be gradually increased or decreased, and the refractive index of the two adjacent layers of material is different, forming a stacked optical structure. By controlling the control component, the thickness changes of these multilayer materials in different areas can be accurately controlled, thereby creating an optical gradient structure with gradually changing thickness to achieve the expected optical efficiency. First, it can adjust the diffraction efficiency of the optical gradient structure according to the needs of different positions, which can improve the uniformity of the display and thus improve the overall display effect. Secondly, this design can also optimize the appearance of the optical gradient structure. Since the thickness changes continuously, the problem of sudden thickness changes is avoided, which not only improves the dimensional accuracy of the structure, but also improves the visual effect.

[0049] Figures 3 to 12 It is a structural schematic diagram of the preparation process of the multilayer optical gradient structure in an embodiment of the present invention.

[0050] Please refer to Figure 3 and Figure 4 , Figure 3 for Figure 4 A top view of Figure 4 for Figure 3 A cross-sectional structural schematic diagram is provided, providing a substrate 200, wherein the substrate 200 includes one or more grating structure regions 201.

[0051] The grating structure region 201 is a region where a material layer is subsequently formed.

[0052] like Figure 3 As shown, Figure 3 A single grating structure region 201 is schematically shown, and a continuous region 20 is schematically shown, wherein the continuous region 20 includes two or more grating structure regions 201, Figure 3 The continuous region 20 in the figure shows three different grating structure regions 201. The different grating structure regions 201 shown in the figure are only examples and do not constitute a limitation on the structure and position of the optical gradient structure. If multiple grating structure regions 201 are independently separated, or divided into regions, or have other structural shapes, etc., they all belong to the grating structure region indicated in the present invention. Figure 3 The various structural regions shown are for simple illustration only.

[0053] The material of the substrate 200 includes an inorganic material or a semiconductor material. The inorganic material includes quartz. The semiconductor material includes silicon, silicon carbide, titanium oxide, lithium niobate, germanium, gallium arsenide, etc.

[0054] Next, at least two target source materials are provided and arranged above the substrate 200; Figure 1 and Figure 2 The control component is arranged between the target source material and the substrate 200, and the second control board 102 is adjacent to the substrate 200; by adjusting the position of the target source material relative to the first through hole and the second through hole 105, at least two material layers with thickness increasing or decreasing successively are formed on any area of ​​the grating structure area.

[0055] In this embodiment, two material layers are formed on the grating structure region 201. The process of forming the two material layers can be found in Figure 5 and Figure 6 .

[0056] Please continue to refer to Figure 5 There is a first distance H' between the first control board 101 and the second control board 102, the first through hole has a first aperture R1, and the second through hole 105 has a second aperture R2.

[0057] The first aperture R1 is the maximum size of the first through hole, and the second aperture R2 is the maximum size of the second through hole 105 .

[0058] In this embodiment, the first aperture R1 ranges from 6 mm to 10 mm.

[0059] In this embodiment, the second aperture R2 ranges from 10 mm to 50 mm.

[0060] In this embodiment, the first spacing H' is in the range of 25 mm to 35 mm.

[0061] In this embodiment, the first control board 101 has a first thickness d1, and the first thickness d1 ranges from 2 micrometers to 500 micrometers.

[0062] In this embodiment, the second control plate 102 has a second thickness d2, and the second thickness d2 is in a range of 2 micrometers to 500 micrometers.

[0063] The second control board 102 is adjacent to the substrate 200 , the first through hole corresponds to the target source material 202 , and the second through hole 105 corresponds to the grating structure region 201 .

[0064] In this embodiment, the second control board 102 is adjacent to the substrate 200 , which includes: the second control board 102 is disposed on the substrate 200 and in contact with the substrate 200 .

[0065] In other embodiments, the second control board is adjacent to the substrate, including: there is a gap between the second control board and the substrate, and the second control board is not in direct contact with the substrate.

[0066] In this embodiment, the surface of the target source material is arranged opposite to the surface of the substrate 200. That is, the sputtering surface of the target source material is opposite to the surface of the substrate 200.

[0067] Please combine Figure 3 Continue to refer Figure 6 , the second through hole 105 corresponds to the grating structure region 201 , including: the second through hole 105 corresponds to a single grating structure region 201 .

[0068] The second through hole 105 corresponds to the grating structure region 201 , and the shape and area of ​​the second through hole 105 determine the shape and area of ​​the material layer formed on the surface of the substrate 200 .

[0069] The material of the material layer includes an inorganic dielectric material or a metal material. The inorganic dielectric material includes titanium oxide, niobium oxide, silicon carbide, silicon oxide, lithium niobate, silicon nitride, tantalum oxide, hafnium oxide, and aluminum oxide; the metal material includes a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, and tantalum.

[0070] In this embodiment, the target source material includes a first target source material 2021 and a second target source material 2022 .

[0071] The material of the first target source material 2021 includes titanium oxide, niobium oxide, silicon carbide, silicon oxide, lithium niobate, silicon nitride, tantalum oxide, hafnium oxide, aluminum oxide or titanium.

[0072] The material of the second target source material 2022 includes titanium oxide, niobium oxide, silicon carbide, silicon oxide, lithium niobate, silicon nitride, tantalum oxide, hafnium oxide, aluminum oxide or titanium.

[0073] Please refer to Figure 5 ,use Figure 1 and Figure 2 The control component forms a first material layer 2031 in the second through hole 105 on the substrate 200 by setting the relative positions of the first target source material 2021 , the first through hole and the second through hole 105 .

[0074] In this embodiment, the center line L11 of the first through hole 1041 is located on the left side of the center line L2 of the second through hole 105, and the thickness variation trend of the first material layer 2031 is as follows: along the direction from the center line L11 of the first through hole 1041 to the center line L2 of the second through hole 105, the thickness of the first material layer 2031 gradually decreases, that is, the thickness of the left side of the first material layer 2031 is large, and the thickness of the right side is small.

[0075] In this embodiment, the thickness of the first material layer 2031 gradually decreases along a target direction, where the target direction is the direction from the first through hole 1041 used to form the first material layer 2031 to the second through hole 105 used to form the first material layer 2031 .

[0076] Please refer to Figure 6 ,use Figure 1 and Figure 2 The control component forms the second material layer 2032 on the first material layer 2031 by setting the relative positions of the second target source material 2022 , the first through hole and the second through hole 105 .

[0077] In this embodiment, the center line L12 of the first through hole 1042 is located on the right side of the center line L2 of the second through hole 105, and the thickness variation trend of the second material layer 2032 is as follows: along the direction from the center line L12 of the first through hole 1042 to the center line L2 of the second through hole 105, the thickness of the second material layer 2032 gradually decreases, that is, the thickness of the second material layer 2032 is larger on the right side and smaller on the left side.

[0078] In this embodiment, the thickness of the second material layer 2032 gradually decreases along a target direction, where the target direction is the direction from the first through hole 1042 used to form the second material layer 2032 to the second through hole 105 used to form the second material layer 2032 .

[0079] In this embodiment, the continuous thickness variation trends of the first material layer 2031 and the second material layer 2032 are opposite. The continuous thickness variation trends of the first material layer 2031 and the second material layer 2032 can offset each other, and the thickness of the optical gradient structure material layer formed by the first material layer 2031 and the second material layer 2032 is uniform.

[0080] In other embodiments, the thickness continuous variation trends of the first material layer and the second material layer can be the same.

[0081] In this embodiment, the second through hole 105 has a first side and a second side relative to each other in the direction along the surface of the second control board 102, and at least two of the first through holes are respectively located on the first side and the second side. Based on the first through hole 1041 on the first side and the first through hole 1042 on the second side, two material layers (a first material layer 2031 and a second material layer 2032) with opposite thickness gradient trends are formed respectively.

[0082] In this embodiment, the refractive indexes of the materials of the first material layer 2031 and the second material layer 2032 are different. The materials of the first material layer 2031 and the second material layer 2032 can be the same or different.

[0083] In this embodiment, the materials of the first target source material 2021 and the second target source material 2022 can be the same or different.

[0084] When the materials of the first target source material 2021 and the second target source material 2022 are the same, the refractive indexes of the first material layer 2031 and the second material layer 2032 are different by adjusting the process parameters in the process of forming the material layers.

[0085] The specific process of adjusting the thickness of the material layer at each position on the grating structure region 201 by adjusting the size of the first spacing H' and the relative positions of the target source material 202, the second through hole 105 and the first through hole is shown in FIG. Figure 7 , Figure 8 and Fig. 9 , Figure 7 A schematic diagram of establishing a coordinate system based on material layers. Figure 8 A schematic diagram of establishing a coordinate system for each structure based on the material layer. Fig. 9 Schematic diagram of coordinates of the relative positions of the target source material 202 , the first through hole and the second through hole 105 .

[0086] Please refer to Figure 7 , taking the intersection of the thickest position of the material layer and the substrate 200 as the coordinate origin O, a coordinate system (x, y) is established, wherein the horizontal coordinate x of the coordinate system (x, y) is the distance of the material layer along the surface of the substrate 200 relative to the coordinate origin O, and the vertical coordinate y of the coordinate system (x, y) is the thickness of any point on the surface of the material layer in a direction perpendicular to the surface of the substrate 200.

[0087] Please refer to Figure 8 , T (x, y) is the thickness of the material layer at a certain position, a (x, y) is a point in the target source material 202, m (x, y) is an arbitrary point in the first through hole, H is the distance between the first control board 101 and the substrate 200, and h is the distance between the center of the target source material 202 and the substrate 200.

[0088] In this embodiment, the height H between the first control board 101 and the substrate 200 is H′+d2, H′ is a first distance between the first control board 101 and the second control board 102, and d2 is a second thickness of the second control board 102.

[0089] In this embodiment, the distance h from the center of the target source material 202 to the surface of the substrate 200 = H + d1 + the distance between the target source material and the first control plate 101 , where d1 is the first thickness of the first control plate 101 .

[0090] In other embodiments, the second control board is not in direct contact with the substrate, and a height H between the first control board and the substrate=H'+d2+a distance between the second control board and the substrate.

[0091] Please refer to Fig. 9 , a(x,y) is a point in the target source material 202, at both ends of the target source material 202, point a(x,y) The critical coordinates of the activity of the target source material 202 are a(x1,y1) , a(x2,y2) ; m(x,y) is any point in the first through hole, and the critical coordinates of the point m(x,y) in the first through hole area are m(x1,y1) and m(x2,y2).

[0092] according to Figure 7 , Figure 8 and Fig. 9 The coordinate system in the second through hole 105 is obtained. a Layer material thickness The calculation formula is defined as: in, is the material density of the a-th material layer, a is a positive integer, and h is the distance from the center of the target source material to the substrate; is the coordinate on the multilayer gradient deposition structure when depositing the a-th material layer The thickness at the point, H is the height between the first control plate and the substrate, m x1 is the critical coordinate value on the left side of the x-axis in the first through-hole region, m x2 m is the critical coordinate value on the right side of the x-axis in the first through hole region; y1 is the critical coordinate value on the left side of the y-axis in the first through-hole region, m y2 is the critical coordinate value on the right side of the y-axis in the first through hole area; x 、a y are the horizontal and vertical coordinate values ​​of any point in the a-th layer from the coordinate center respectively; is the integral of any point on the target source material outlet of the a-th material layer along the center of the target source material; is the deposition rate of the a-th material layer; the control component is arranged on the surface of the substrate when preparing the multi-layer optical gradient structure.

[0093] By adjusting the relative positions of the target source material 202, the center line of the first through hole and the center line L2 of the second through hole 105, the thickness of the a-th material layer in the second through hole 105 is controlled. And thickness variation trend.

[0094] Specifically, the thickness variation trend of the material layer is that the thickness of the material layer gradually decreases along the direction from the center line L1 of the first through hole to the center line L2 of the second through hole 105 . Figure 5 It is shown in the figure that the center line L11 of the first through hole is located on the left side of the center line L2 of the second through hole 105 , so the thickness variation trend of the material layer is: in the second through hole 105 , the thickness of the material layer gradually decreases from the left side to the right side.

[0095] The above formula is used to calculate the thickness T(x, y) of the material layer at different positions x, so as to determine the thickness variation of the material layer at different positions. The thickness T(x, y) of the material layer at different positions is calculated based on different technical requirements or gradient requirements of the grating depth.

[0096] Please refer to Fig.10 , Fig.10 For Fig. 9 Based on the schematic diagram, a(x, y) is a point in the target source material 202. At both ends of the target source material 202, the critical coordinates of the point a(x, y) in the target source material 202 are a(x1,y1) , a(x2,y2) ; m(x,y) is any point in the first through hole, the critical coordinates of point m(x,y) in the first through hole area are m(x1,y1) and m(x2,y2); the critical coordinates of point m(x,y) in the second through hole 105 area are u(x1,y1) and u(x2,y2).

[0097] By adjusting the relative positions of the target source material 202, the center line of the first through hole and the center line L2 of the second through hole 105, the relative positions of the target source material 202 relative to the first through hole and the second through hole 105 meet preset conditions, and the preset conditions include:

[0098] in, a x1 , a y1 They respectively represent the critical coordinate values ​​of the left boundary in the activity range of the target source material 202; a x2 , ay2 They respectively represent the critical coordinate values ​​of the right boundary of the active range of the target source material 202; H is the distance between the first control plate 101 and the substrate 200; h is the distance from the center of the target source material 202 to the surface of the substrate 200; m x1 is the critical coordinate value on the left side of the x-axis in the first through-hole region, m x2 m is the critical coordinate value on the right side of the x-axis in the first through hole region; y1 is the critical coordinate value on the left side of the y-axis in the first through-hole region, m y2 u is the critical coordinate value on the right side of the y-axis in the first through hole area; x1 is the critical coordinate value on the left side of the x-axis in the second through hole 105 region, u y1 u is the critical coordinate value on the left side of the y-axis in the second through hole 105 area; x2 is the critical coordinate value on the right side of the x-axis in the second through hole 105 area, u y2 is the critical coordinate value on the right side of the y-axis in the second through hole 105 area.

[0099] In the above formula, the relative positions of the target source material 202 , the first through hole, and the second through hole 105 meet the preset conditions, and can ensure that a material layer with a required continuously varying thickness is formed in the second through hole 105 .

[0100] The thickness of the material layer gradually decreases along the direction from the center line of the first through hole to the center line L2 of the second through hole 105. Specifically, the thickness of the material layer in the second through hole 105 continuously changes from 15 nanometers to 400 nanometers along the direction from the center line of the first through hole to the center line L2 of the second through hole 105.

[0101] Please refer to Fig.11 , a patterned mask layer 210 is formed on the second material layer 2032 .

[0102] Please refer to Fig.12 , the second material layer 2032 and the first material layer 2031 are etched using the patterned mask layer 210 as a mask to form an optical gradient structure on the substrate 200, wherein the optical gradient structure includes a first optical layer 2061 and a second optical layer 2062 located on the first optical layer 2061. The refractive index of the second optical layer 2062 on the first optical layer 2061 is different. In this embodiment, the required structure is formed by etching once, and the preparation process is simple and efficient.

[0103] Of course, in Fig.12 In the embodiment, only two optical layers are shown. In some other embodiments, such as the combination of Fig.16 , Fig.21etc., and may also include three, four, or even more optical layers to form at least two optical layers with different refractive indices; in this regard, Fig.12 The embodiments are not intended to limit the number of optical layers in the present invention.

[0104] In summary, by setting the relative positions of the target source material, the first through hole and the second through hole 105, an optical gradient structure is formed on the substrate 200 through two processes of forming material layers. The optical gradient structure has two optical layers with different refractive indices, and an optical gradient structure with a multi-layer thickness gradient can be prepared. On the one hand, based on this structural design, the diffraction efficiency modulation of the optical gradient structure at different positions can be realized to improve the display uniformity of the optical gradient structure at different positions and improve the display effect; on the other hand, the design of the structure can also improve the display appearance of the optical gradient structure. The design of continuous thickness gradient can prevent sudden changes in thickness at different positions. Such a design improves the dimensional accuracy and visual effect of the optical gradient structure.

[0105] The formation method, by arranging the above-mentioned control component between the target source material and the substrate, the second through hole corresponds to the grating structure area, the first through hole corresponds to the target source material, and controlling the relative positions of the target source material, the first through hole and the second through hole and the sputtering process, can form at least two material layers with thicknesses increasing or decreasing successively on any area of ​​the grating structure area, can accurately control the display appearance of the optical gradient structure, especially, it is not easy to have sudden stripes between different grating structure areas, so that the thickness of different grating structure areas is continuously gradient, thereby improving the display appearance of the formed optical gradient structure and modulating the diffraction efficiency of the optical gradient structure at different positions; and further, based on this method, a grating structure in a diffraction optical waveguide is formed, thereby forming a grating structure with a continuous gradient in depth, different grating structures have different depths, and the gradient trends of multiple material layers are opposite, and the refractive indices of two adjacent layers of materials are different, thereby realizing the deposition of materials with different refractive indices. On the one hand, the method modulates the diffraction efficiency of the prepared grating structure at different positions, and selects the refractive index of the deposited material and the refractive index at different positions based on the diffraction efficiency requirement, so that the grating structure has the selected refractive index at different positions, such as the defined continuously gradient diffraction efficiency, thereby improving the display uniformity of the diffraction optical waveguide and improving the display effect of the waveguide; on the other hand, based on the diffraction optical waveguide obtained in this way, different grating structures have continuously gradient depths at different positions, which is different from the existing partition structure in display appearance, so as to achieve a smooth transition of grating areas with different diffraction efficiencies, thereby preventing the visual difference caused by the sudden change of thickness at different positions, and visually obtaining a better appearance effect.

[0106] Fig.13 and Fig.14It is a schematic structural diagram of a control component for preparing a multilayer optical gradient structure in another embodiment of the present invention.

[0107] Please refer to Fig.13 and Fig.14 , Fig.13 for Fig.14 A top view of Fig.14 for Fig.13 Schematic diagram of the structure along the section line CC1, Fig.13 and Fig.14 The control components in Figure 1 and Figure 2 The difference between the control component and the control component is that the number of the first through holes is 3.

[0108] In this embodiment, the three first through holes are marked as 1041 , 1042 and 1043 respectively, and the three first through holes marked as 1041 , 1042 and 1043 are arranged in an isosceles triangle or an equilateral triangle.

[0109] In this embodiment, the number of the second through hole 105 is one.

[0110] In other embodiments, the number of the second through holes is two or more.

[0111] In other embodiments, when the second control plate includes two second through holes, one of the second through holes corresponds to a turning grating structure region, and the other second through hole corresponds to a coupling-out grating structure region, and the material layers corresponding to the turning grating structure and the coupling-out grating structure are formed simultaneously in the two second through holes.

[0112] In this embodiment, the projection range of each first through hole projected on the second control board 102 partially overlaps with the projection range of the second through hole 105 projected on the second control board 102. That is, the second through hole 105 is arranged at the center of the triangle formed by the three first through holes marked as 1041, 1042 and 1043, so as to ensure that the projection of each first through hole on the second control board 102 can overlap with part of the second through hole 105.

[0113] In other embodiments, a projection range of each first through hole projected onto the second control plate does not overlap with a projection range of the second through hole projected onto the second control plate.

[0114] In this embodiment, the diameters and areas of the three first through holes may be the same or different.

[0115] Fig.15 and Fig.16 It is a structural schematic diagram of the preparation process of a multilayer optical gradient structure in another embodiment of the present invention.

[0116] In this embodiment, the optical gradient structure material layer includes three material layers with continuously changing thicknesses. The continuously changing thicknesses of the material layers include: gradually increasing thicknesses, or gradually decreasing thicknesses.

[0117] In this embodiment, the thicknesses of two adjacent material layers have opposite continuous variation trends.

[0118] In other embodiments, the continuous thickness variation trends of two adjacent material layers may be the same.

[0119] Please refer to Fig.15 ,use Fig.13 and Fig.14 The control component in the optical gradient structure material layer is formed on the substrate 200 , and the optical gradient structure material layer includes a first material layer 2031 , a second material layer 2032 located on the first material layer 2031 , and a third material layer 2033 located on the second material layer 2032 .

[0120] The formation process of the optical gradient structure material layer can be found in Figure 5 Hezhi Fig.10 The process steps described in the above will not be repeated here.

[0121] In this embodiment, the thickness continuous change trends of two adjacent material layers are opposite. That is, the thickness continuous change trends of the first material layer 2031 and the second material layer 2032 are opposite, and the thickness continuous change trends of the second material layer 2032 and the third material layer 2033 are opposite. The thickness continuous change trends of the first material layer 2031 and the second material layer 2032 can offset each other, and the thickness change trend of the optical gradient structure material layer is the same as the thickness change trend of the third material layer 2033.

[0122] In other embodiments, the thickness continuous variation trends of two adjacent layers of the first material layer 2031 , the second material layer 2032 , and the third material layer 2033 may be the same.

[0123] In this embodiment, the refractive indexes of two adjacent material layers are different, that is, the refractive indexes of the first material layer 2031 and the second material layer 2032 are different, and the refractive indexes of the second material layer 2032 and the third material layer 2033 are different.

[0124] The materials of the first material layer 2031 and the second material layer 2032 can be the same or different. When the materials of the first material layer 2031 and the second material layer 2032 are the same, the refractive indexes of the materials of the first material layer 2031 and the second material layer 2032 are different by adjusting the process parameters in the process of forming the material layers.

[0125] The materials of the second material layer 2032 and the third material layer 2033 may be the same or different. When the materials of the second material layer 2032 and the third material layer 2033 are the same, the refractive index of the materials of the second material layer 2032 and the third material layer 2033 may be different by adjusting the process parameters in the process of forming the material layer.

[0126] Please refer to Fig.16 , the third material layer 2033, the second material layer 2032 and the first material layer 2031 are etched to form an optical gradient structure on the substrate 200, wherein the optical gradient structure includes a first optical layer 2061, a second optical layer 2062 located on the first optical layer 2061 and a third optical layer 2063 located on the second optical layer 2062. The refractive indexes of two adjacent optical layers are different.

[0127] The process of etching the third material layer 2033, the second material layer 2032 and the first material layer 2031 to form an optical gradient structure on the substrate 200 is described in detail in detail. Fig.11 and Fig.12 The description in will not be repeated here.

[0128] In summary, by setting the relative positions of the first through hole and the second through hole 105, an optical gradient structure is formed on the substrate 200 through three processes of forming material layers. The optical gradient structure has three optical layers with different refractive indices, and an optical gradient structure with a multi-layer thickness gradient can be prepared. On the one hand, based on this structural design, the diffraction efficiency modulation of the optical gradient structure at different positions can be realized to improve the display uniformity of the optical gradient structure at different positions and improve the display effect; on the other hand, the design of the structure can also improve the display appearance of the optical gradient structure. The design of continuous thickness gradient can prevent sudden changes in thickness at different positions. Such a design improves the dimensional accuracy and visual effect of the optical gradient structure.

[0129] Figures 17 to 19 It is a schematic structural diagram of a control component for preparing a multilayer optical gradient structure in another embodiment of the present invention.

[0130] Please refer to Figures 17 to 19 , Fig.17 for Fig.18 and Fig.19 A top view of Fig.18 for Fig.17 Schematic diagram of the structure along the section line DD1, Fig.19 for Fig.17 Schematic diagram of the structure along the section line EE1, Figures 17 to 19 The control components in Figure 1 and Figure 2The difference between the control component and the control component is that the number of the first through holes is 4.

[0131] In this embodiment, the four first through holes are marked as 1041, 1042, 1043 and 1044, and the four first through holes marked as 1041, 1042, 1043 and 1044 are arranged in an array of equal rows and columns. The four first through holes marked as 1041, 1042, 1043 and 1044 form a rectangular shape. Among them, the center lines of the first through holes marked as 1041, 1042, 1043 and 1044 are L11, L12, L13, L14 respectively.

[0132] In this embodiment, the number of the second through hole 105 is one.

[0133] In other embodiments, the number of the second through holes is two or more.

[0134] In other embodiments, when the second control plate includes two second through holes, one of the second through holes corresponds to a turning grating structure region, and the other second through hole corresponds to a coupling-out grating structure region, and the material layers corresponding to the turning grating structure and the coupling-out grating structure are formed simultaneously in the two second through holes.

[0135] In this embodiment, the projection range of each first through hole projected on the second control board 102 partially overlaps with the projection range of the second through hole 105 projected on the second control board 102. That is, the second through hole 105 is arranged at the center of the rectangle formed by four first through holes marked as 1041, 1042, 1043 and 1044, so as to ensure that the projection of each first through hole on the second control board 102 can overlap with part of the second through hole 105.

[0136] In other embodiments, a projection range of each first through hole projected onto the second control plate does not overlap with a projection range of the second through hole projected onto the second control plate.

[0137] In this embodiment, the diameters and areas of the four first through holes may be the same or different.

[0138] Fig. 20 and Fig.21 It is a structural schematic diagram of the preparation process of a multilayer optical gradient structure in another embodiment of the present invention.

[0139] In this embodiment, the optical gradient structure material layer includes four material layers with continuously changing thicknesses. The continuously changing thicknesses of the material layers include: gradually increasing thicknesses, or gradually decreasing thicknesses.

[0140] In this embodiment, the thicknesses of two adjacent material layers have opposite continuous variation trends.

[0141] In other embodiments, the continuous thickness variation trends of two adjacent material layers may be the same.

[0142] Please refer to Fig. 20 ,use Figures 17 to 19 The control component forms an optical gradient structure material layer on the substrate 200, and the optical gradient structure material layer includes a first material layer 2031, a second material layer 2032 located on the first material layer 2031, a third material layer 2033 located on the second material layer 2032, and a fourth material layer 2034 located on the third material layer 2033.

[0143] The formation process of the optical gradient structure material layer can be found in Figure 5 Hezhi Fig.10 The process steps in the above steps will not be described in detail here.

[0144] In this embodiment, the thickness continuous change trends of two adjacent material layers are opposite. That is, the thickness continuous change trends of the first material layer 2031 and the second material layer 2032 are opposite, the thickness continuous change trends of the second material layer 2032 and the third material layer 2033 are opposite, and the thickness continuous change trends of the third material layer 2033 and the fourth material layer 2034 are opposite. The thickness continuous change trends of the first material layer 2031 and the second material layer 2032 can offset each other, and the thickness continuous change trends of the third material layer 2033 and the fourth material layer 2034 can offset each other. The thickness of the optical gradient structure material layer is uniform.

[0145] In other embodiments, the continuous thickness variation trends of two adjacent first material layer 2031 , second material layer 2032 , third material layer 2033 and fourth material layer 2034 may be the same.

[0146] In this embodiment, the refractive indexes of two adjacent material layers are different, that is, the refractive indexes of the first material layer 2031 and the second material layer 2032 are different, the refractive indexes of the second material layer 2032 and the third material layer 2033 are different, and the refractive indexes of the third material layer 2033 and the fourth material layer 2034 are different.

[0147] The materials of the first material layer 2031 and the second material layer 2032 can be the same or different. When the materials of the first material layer 2031 and the second material layer 2032 are the same, the refractive indexes of the materials of the first material layer 2031 and the second material layer 2032 are different by adjusting the process parameters in the process of forming the material layers.

[0148] The materials of the second material layer 2032 and the third material layer 2033 may be the same or different. When the materials of the second material layer 2032 and the third material layer 2033 are the same, the refractive index of the materials of the second material layer 2032 and the third material layer 2033 may be different by adjusting the process parameters in the process of forming the material layer.

[0149] The materials of the third material layer 2033 and the fourth material layer 2034 can be the same or different. When the materials of the third material layer 2033 and the fourth material layer 2034 are the same, the refractive index of the third material layer 2033 and the fourth material layer 2034 can be different by adjusting the process parameters in the process of forming the material layer.

[0150] Please refer to Fig.21 , the fourth material layer 2034, the third material layer 2033, the second material layer 2032 and the first material layer 2031 are etched to form an optical gradient structure on the substrate 200, the optical gradient structure comprising a first optical layer 2061, a second optical layer 2062 located on the first optical layer 2061, a third optical layer 2063 located on the second optical layer 2062 and a fourth optical layer 2064 located on the third optical layer 2063. The refractive indexes of two adjacent optical layers are different.

[0151] The process of etching the fourth material layer 2034, the third material layer 2033, the second material layer 2032 and the first material layer 2031 to form an optical gradient structure on the substrate 200 is described in detail in detail. Fig.19 and Fig. 20 The description in will not be repeated here.

[0152] In summary, by setting the relative positions of the target source material, the first through hole and the second through hole 105, an optical gradient structure is formed on the substrate 200 through four processes of forming material layers. The optical gradient structure has four optical layers with different refractive indices, and an optical gradient structure with a multi-layer thickness gradient can be prepared. On the one hand, based on this structural design, the diffraction efficiency modulation of the optical gradient structure at different positions can be achieved to improve the display uniformity of the optical gradient structure at different positions and improve the display effect; on the other hand, the design of the structure can also improve the display appearance of the optical gradient structure. The design of continuous thickness gradient can prevent sudden changes in thickness at different positions. Such a design improves the dimensional accuracy and visual effect of the optical gradient structure.

[0153] In another embodiment, the grating structure region on the surface of the substrate has a grating structure, a plurality of the grating structures are separated on the substrate, and the heights of the plurality of the grating structures are the same. A plurality of the material layers are located on the sidewall surface and the top surface of the grating structure, and along the arrangement direction of the plurality of the grating structures, the thickness of the material layers located on the sidewall surface and the top surface of the grating structure gradually increases or gradually decreases.

[0154] In another embodiment, the grating structure region of the substrate has a grating structure, and the substrate and the grating structure surface in the substrate are flat, that is, the tops of the plurality of grating structures are flush with the top of the base. The plurality of material layers are located on the sidewall surface and the top surface of the grating structure, and along the arrangement direction of the plurality of grating structures, the thickness of the material layers located on the sidewall surface and the top surface of the grating structure gradually increases or decreases.

[0155] In another embodiment, a method for preparing a multi-layer optical gradient structure includes: forming a first material layer on the grating structure region; etching the first material layer, forming a first grating structure based on the first material layer; forming a second material layer on the surface of the first grating structure; etching the second material layer, and forming a second grating structure based on the second material layer, and continuing to form a third material layer on the second grating structure; repeating the above steps until the multi-layer optical gradient structure is obtained. In this way, the period, duty cycle, etc. of each layer of the grating structure can be controlled, with greater design freedom.

[0156] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A control component for preparing a multilayer optical gradient structure, characterized in that: The control component comprises: A first control plate and a second control plate having a preset spacing; the first control plate comprises at least two first through holes, the second control plate comprises at least one second through hole, and the center lines of at least two of the first through holes and at least one of the second through holes do not overlap; The control component is used to deposit the multi-layer optical gradient structure in the second through hole, and the multi-layer optical gradient structure includes at least two material layers, and the thickness of each material layer gradually decreases along the target direction, and the target direction is the direction from the first through hole used to form the material layer to the second through hole used to form the material layer.

2. The control component for preparing a multilayer optical gradient structure according to claim 1, characterized in that: The material layer is used to form a turning grating and / or an outcoupling grating of a diffraction optical waveguide, and the depth of the turning grating and / or the outcoupling grating gradually increases along the direction of light transmission.

3. A control component for preparing a multi-layer optical gradient structure according to claim 1 or 2, characterized in that: The multilayer optical gradient structure a Layer material thickness T(x,y,t a ) The calculation formula is defined as: in, For the a Layer Material The material density of the layer, a Take a positive integer, h is the distance from the center of the target source material to the substrate; T(x, y,t a ) For the deposition a Coordinates of multi-layer gradient deposition structures when layers of materials are deposited (x,y,t a ) The thickness at the point, H is the height between the first control plate and the substrate, m x1 is the critical coordinate value on the left side of the x-axis in the first through-hole region, m x2 m is the critical coordinate value on the right side of the x-axis in the first through hole region; y1 is the critical coordinate value on the left side of the y-axis in the first through-hole region, m y2 is the critical coordinate value on the right side of the y-axis in the first through hole area; a x、 a y Respectively a The horizontal and vertical coordinate values ​​of any point in the layer from the coordinate center; For the a The control component is used to control the deposition rate of the layer material layer; and the control component is arranged on the surface of the substrate when preparing the multi-layer optical gradient structure.

4. The control component for preparing a multi-layer optical gradient structure according to claim 3, characterized in that: The second through hole has a first side and a second side relative to each other in the direction along the surface of the second control board, and at least two of the first through holes are respectively located on the first side and the second side. Based on the first through holes on the first side and the first through holes on the second side, two material layers with opposite thickness gradient trends are respectively formed.

5. The control component for preparing a multi-layer optical gradient structure according to claim 4, characterized in that: The refractive indices of two adjacent material layers are different.

6. The control component for preparing a multi-layer optical gradient structure according to claim 2, characterized in that: The second control plate includes two second through holes, one of which corresponds to a turning grating structure region, and the other corresponds to an outcoupling grating structure region, and the material layers corresponding to the turning grating structure and the outcoupling grating structure are formed simultaneously in the two second through holes.

7. A method for preparing a multilayer optical gradient structure, characterized in that: include: providing a substrate, the substrate comprising one or more grating structure regions; Providing at least two target source materials, disposed above the substrate; Providing the control component according to any one of claims 1 to 6, and placing the control component between the target source material and the substrate and in contact with the surface of the substrate; By adjusting the position of the target source material relative to the first through hole and the second through hole, at least two material layers are formed on any area of ​​the grating structure area, and the thickness of each material layer gradually decreases along the target direction, and the target direction is the direction in which the first through hole used to form the material layer points to the second through hole used to form the material layer.

8. A method for preparing a multilayer optical gradient structure according to claim 7, characterized in that: The relative position of the target source material relative to the first through hole and the second through hole meets a preset condition, and the preset condition includes: ， in, a x1 , a y1 They respectively represent the critical coordinate values ​​of the left boundary in the activity range of the target source material; a x2 , a y2 They respectively represent the critical coordinate values ​​of the right boundary of the target source material's activity range; H is the distance between the first control plate and the substrate; h is the distance from the center of the target source material to the substrate surface; m x1 is the critical coordinate value on the left side of the x-axis in the first through-hole region, m x2 is the critical coordinate value on the right side of the x-axis in the first through hole region; m y1 is the critical coordinate value on the left side of the y-axis in the first through-hole region, m y2 is the critical coordinate value on the right side of the y-axis in the first through hole region; u x1 is the critical coordinate value on the left side of the x-axis in the second through-hole region, u y1 is the critical coordinate value on the left side of the y-axis in the second through-hole region; u x2 is the critical coordinate value on the right side of the x-axis in the second through-hole region, u y2 is the critical coordinate value on the right side of the y-axis in the second through hole area.

9. A method for preparing a multilayer optical gradient structure according to claim 7, characterized in that: The grating structure region on the surface of the substrate has a grating structure, and the material layer is formed on the surface of the grating structure away from the substrate; or, the substrate has a grating structure in the grating structure region, the surfaces of the substrate and the grating structure in the substrate are flat, and at least two layers of the material layer are formed in the grating structure region to form a multi-layer optical gradient grating structure on the grating structure region.

10. A method for preparing a multilayer optical gradient structure, characterized in that: include: providing a substrate, the substrate comprising a grating structure region; Providing at least two target source materials, disposed above the substrate; Providing the control assembly according to any one of claims 1 to 6, and placing it between the target source material and the substrate and in contact with the surface of the substrate; A first material layer is formed on the grating structure region, and a first grating structure is formed based on the first material layer. A second material layer is formed on the surface of the first grating structure, and a second grating structure is formed based on the second material layer. A third material layer is continuously formed on the second grating structure until the multi-layer optical gradient structure is obtained.

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