Control Component and Method for Preparing Multilayer Optical Gradient Structure

Abstract

A control component and method for preparing a multi-layer optical gradient structure, the method comprising: providing a substrate, the substrate including one or more grating structure regions; providing at least two target source materials disposed above the substrate; providing a control component and placing the control component between the target source materials and the substrate and in contact with the surface of the substrate; forming at least two material layers on any region of the grating structure region by adjusting the positions of the target source materials relative to a first through-hole and a second through-hole, and the thickness of each material layer gradually decreases along a target direction, the target direction being the direction from the first through-hole used to form the material layer to the second through-hole used to form the material layer. To achieve precise control of the continuous change in the thickness of the multi-layer optical gradient structure.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly 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, the diffractive optical waveguide has a large eye movement range, a small volume, and good mass production performance. In order to achieve uniform field of view, uniform color, and efficient optical transmission effects, the industry is constantly striving to improve the design and manufacturing process of diffractive optical waveguides. Especially during the manufacturing process, how to efficiently produce diffractive optical waveguides has become a research hotspot.

[0003] At the same time, how to optimize the display appearance of these structures while ensuring the diffraction efficiency of the diffractive optical waveguide remains an issue that needs to be continuously addressed. Summary of the Invention

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

[0005] To solve the above technical problem, an embodiment of the present invention provides a control component for preparing a multi-layer optical gradient structure. The control component includes: a first control board and a second control board with a preset spacing; the first control board includes at least two first through holes, the second control board includes at least one second through hole, and the centerlines of at least two of the first through holes and at least one of the second through holes do not coincide; the control component is used to deposit and form the multi-layer optical gradient structure in the second through hole, and the multi-layer optical gradient structure includes at least two material layers with gradually increasing or decreasing thickness, and the material sequentially passes through the first through hole and the second through hole when depositing to form the material layer.

[0006] Optionally, the material layer is used to form a turning grating and / or an outcoupling grating of a diffractive 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 second through hole has opposite first and second sides along the direction of the second control board surface, 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.

[0008] Optionally, the refractive indices of adjacent two material layers are different.

[0009] Optionally, the second control board includes two second through-holes. One of the second through-holes corresponds to the turning grating structure region, and the other second through-hole corresponds to the coupling-out grating structure region. The material layers corresponding to the turning grating structure and the coupling-out grating structure are simultaneously formed in the two second through-holes respectively.

[0010] Correspondingly, the technical solution of the present invention further provides a method for preparing a multi-layer optical gradient structure, including: providing a substrate, the substrate including one or more grating structure regions; providing at least two target source materials and disposing them above the substrate; providing a control component and placing the control component between the target source materials and the substrate and in contact with the surface of the substrate; forming at least two material layers with gradually increasing or decreasing thicknesses on any region of the grating structure region by adjusting the positions of the target source materials relative to the first through-hole and the second through-hole.

[0011] Optionally, the relative positions of the target source materials with respect to the first through-hole and the second through-hole satisfy a preset condition, and the preset condition includes:

[0012]

[0013]

[0014]

[0015]

[0016] wherein, 、 respectively represent the left boundary critical coordinate values in the active range of the target source material; 、 respectively represent the right boundary critical coordinate values in the active range of the target source material; is the distance between the first control board and the substrate; is the distance from the center of the target source material to the surface of the substrate; is the left boundary critical coordinate value in the axis in the first through-hole region, is the right boundary critical coordinate value in the axis in the first through-hole region; is the left boundary critical coordinate value in the axis in the first through-hole region, is the right boundary critical coordinate value in the axis in the first through-hole region; is the left boundary critical coordinate value in the axis in the second through-hole region, is the left boundary critical coordinate value in the axis in the second through-hole region; is the critical coordinate value on the right side of the y-axis in the second through-hole area of the y-axis, is the critical coordinate value on the right side of the y-axis in the second through-hole area.

[0017] Optionally, a grating structure is provided in the grating structure area on the surface of the substrate, and the material layer is formed on the surface of the grating structure away from the substrate; or, a grating structure is provided in the grating structure area of the substrate, the surface of the grating structure in the substrate is flat, and at least two material layers with gradually increasing or decreasing thicknesses are formed in the grating structure area to form a multi-layer optical gradient grating structure on the material layer.

[0018] Correspondingly, the technical solution of the present invention also provides a method for preparing a multi-layer optical gradient structure, including: providing a substrate, the substrate including a grating structure area; providing at least two target source materials and disposing them above the substrate; providing a control component and placing it between the target source materials and the substrate and in contact with the surface of the substrate; forming a first material layer with gradually increasing or decreasing thickness on the grating structure area, and forming a first grating structure based on the material layer, forming a second material layer with gradually increasing or decreasing thickness on the surface of the first grating structure, and forming a second grating structure based on the material layer, and continuing to form a material layer on the second grating structure until the multi-layer optical gradient structure is obtained.

[0019] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0020] The control component in this technical solution includes a first control board and a second control board, thereby constructing an optical gradient structure in the second through-hole area of the second control board. This optical gradient structure includes at least two layers of materials, the thickness of each layer can gradually increase or decrease, forming a stacked optical structure, and the refractive index of each layer of material is different. By controlling the control component, the thickness change of these multi-layers of 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 desired 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. Second, this design can also optimize the appearance of the optical gradient structure. Since the thickness changes continuously, the problem of sudden thickness change is avoided, which not only improves the dimensional accuracy of the structure but also enhances the visual effect.

[0021] Method for forming an optical gradient structure of the technical solution of the present invention. By disposing the above control component between the target source material and the substrate, the second window through-hole corresponds to the grating structure region of the optical gradient structure region, and the first window through-hole corresponds to the target source material. By controlling the relative positions of the target source material, the first window through-hole, and the second window through-hole and the sputtering process, at least two material layers with sequentially increasing or decreasing thicknesses can be formed on any region of the grating structure region, and the refractive indices of adjacent two layers of materials are different. It can precisely control the display appearance of the optical gradient structure. In particular, it is not easy to appear abrupt stripes between different optical gradient structure regions (grating structure regions), so that the thicknesses of different optical gradient structure regions (grating structure regions) are 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 diffractive optical waveguide is formed, thereby forming a grating structure with continuously gradient depth, different grating structures having different depths, and the gradient trends of multiple material layers being opposite, thereby realizing the deposition of materials with different refractive indices. On the one hand, this method enables the diffraction efficiency of the prepared grating structure at different positions to be modulated. Based on the requirements of the diffraction efficiency, the refractive index of the deposited material and the refractive indices at different positions are selected, so that the grating structure has the selected refractive index at different positions, such as the continuously gradient diffraction efficiency as defined, thereby improving the display uniformity of the diffractive optical waveguide and improving the display effect of the waveguide; on the other hand, based on the obtained diffractive optical waveguide, different grating structures have continuously gradient depths at different positions, which is different from the existing partition structure in terms of display appearance, so as to achieve a smooth transition of grating regions with different diffraction efficiencies, thereby preventing visual differences caused by abrupt thickness changes at different positions and obtaining a better visual appearance effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 and Figure 2 FIG. is a schematic structural diagram of a control component for preparing a multi-layer optical gradient structure in an embodiment of the present invention;

[0023] Figures 3 to 12 FIG. is a schematic structural diagram of the process for preparing a multi-layer optical gradient structure in an embodiment of the present invention;

[0024] Figure 13 and Figure 14 FIG. is a schematic structural diagram of a control component for preparing a multi-layer optical gradient structure in another embodiment of the present invention;

[0025] Figure 15 and Figure 16 FIG. is a schematic structural diagram of the process for preparing a multi-layer optical gradient structure in another embodiment of the present invention;

[0026] Figures 17 to 19It is a schematic structural diagram of a control component for preparing a multi-layer optical gradient structure in another embodiment of the present invention;

[0027] Figure 20 and Figure 21 It is a schematic structural diagram of the preparation process of a multi-layer optical gradient structure in another embodiment of the present invention. Detailed implementation manners

[0028] As described in the background art, how to optimize the optical gradient structure while ensuring the diffraction efficiency of the optical gradient structure to achieve a highly continuous change is a problem that needs to be continuously solved.

[0029] Specifically, in the field of micro-nano optical gradient structure design, in some cases, for specific optical elements that need to regulate performance parameters by thickness change, precisely achieving a continuous gradient of thickness is a technical challenge. The thickness change of such structures is usually at the level of dozens of nanometers, which is particularly crucial for nano-scale fine control because it directly relates to the functional realization of optical elements and how to form a micro-nano structure with a continuous thickness change. For example, in diffraction optical waveguide technology, the depth gradient modulation of the grating structure is crucial for adjusting the diffraction efficiency distribution.

[0030] In addition, when forming an optical gradient structure with a continuous thickness change, it is easy to form mutation stripes during the thickness gradient between different gradient regions. The mutation stripe is the position where the thickness of the optical gradient structure mutates, and this mutation stripe will affect the appearance of the product formed by the optical gradient structure and is not easily acceptable to consumers visually. Therefore, it is necessary to improve the generation of mutation stripes and precisely control the continuous thickness change of the optical gradient structure. Further, for example, in the grating structure of a diffraction optical waveguide, it is necessary to achieve continuous gradient modulation of the grating depth to modulate the visibility of the grating structure in the diffraction optical waveguide.

[0031] To solve the above problems, embodiments of the present invention provide a control component and method for preparing a multi-layer optical gradient structure. By disposing the above deposition assisting structure between the target source material and the substrate, the second window through-hole corresponds to the grating structure region of the optical gradient structure region, and the first window through-hole corresponds to the target source material. By controlling the relative positions of the target source material, the first window through-hole, and the second window through-hole and the sputtering process, at least two material layers with sequentially increasing or decreasing thicknesses can be formed on any region of the grating structure region, and the display appearance of the optical gradient structure can be precisely controlled. In particular, there are no sudden change stripes easily appearing between different optical gradient structure regions (grating structure regions), so that the thicknesses of different optical gradient structure regions (grating structure regions) are 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 continuously gradient depth, and different grating structures have different depths.

[0032] To make the above objects, features, and beneficial effects of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given with reference to the accompanying drawings.

[0033] Figure 1 and Figure 2 are schematic structural diagrams of a control component for preparing a multi-layer optical gradient structure in an embodiment of the present invention.

[0034] Please refer to Figure 1 and Figure 2 , Figure 1 is Figure 2 a top view of Figure 2 is Figure 1 a schematic structural diagram along the section line BB1 direction. The control component for preparing a multi-layer optical gradient structure includes: a first control board 101 and a second control board 102 with a preset spacing; the first control board 101 includes at least two first through-holes, the second control board 102 includes 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 coincide;

[0035] The control component is used to deposit and form an optical gradient structure in the second through-hole 105. The optical gradient structure includes at least two material layers with sequentially increasing or decreasing thicknesses, and the material passes through the first through-hole and the second through-hole 105 in sequence when depositing to form the material layer.

[0036] 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 regions where the material layers are to be formed.

[0037] In this embodiment, the number of the first through holes is two; the number of the second through holes 105 is one.

[0038] In other embodiments, the number of the first through holes is three or more than three, and the number of the second through holes is two or more than two.

[0039] In other embodiments, when the second control board includes two second through holes, one of the second through holes corresponds to the turning grating structure region, and the other second through hole corresponds to the coupling-out grating structure region. The material layers corresponding to the turning grating structure and the coupling-out grating structure are simultaneously formed in the two second through holes respectively.

[0040] In this embodiment, the two first through holes are respectively marked as 1041 and 1042. The two first through holes marked as 1041 and 1042 are arranged in a row or a column. The projection range of each first through hole on the second control board 102 partially overlaps with the projection range of the second through hole 105 on the second control board 102. That is, the second through hole 105 is arranged at the 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.

[0041] In this embodiment, the apertures and areas of the two first through holes may be the same or different.

[0042] In this embodiment, the two first through holes marked as 1041 and 1042 respectively have center lines L11 and L12. The distance between the center line L2 of the second through hole 105 and the center line L11 is the same as the distance between the center line L2 of the second through hole 105 and the center line L12.

[0043] In this embodiment, the control component further includes: a connecting portion 103. 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 by the connecting portion 103 to form an integrated structure, and the second control board 102 is bonded to the substrate.

[0044] In other embodiments, the control component may not include the connecting portion. The first control board and the second control board are respectively independently formed on the substrate, and the second control board contacts the substrate.

[0045] The embodiments of the above two connection methods of the control component are all within the protection scope of the present invention. As long as it does not depart from the purpose required to be protected by the present invention, that is, to achieve a material layer with continuously varying thickness, there is no limitation on the connection method of the control component.

[0046] In this embodiment, the projection range of the first through-hole on the second control board 102 partially overlaps with the range of the second through-hole 105, and there is an overlapping area between the projection range of the first through-hole on the second control board 102 and the range of the second through-hole 105.

[0047] In other embodiments, the projection range of the first through-hole on the second control board does not overlap with the range of the second through-hole.

[0048] The centerlines of at least two of the first through-holes and at least one of the second through-holes 105 do not coincide, including: the centerlines of each of the first through-holes and each of the second through-holes 105 do not coincide; or, the overall centerline of at least two first through-holes does not coincide with the overall centerline of at least one second through-hole 105.

[0049] In this embodiment, the centerline of the first through-hole does not coincide with the centerline L2 of the second through-hole 105, that is, the centerline of any one of the first through-holes does not coincide with the centerline L2 of any one of the second through-holes 105. To precisely control the process of forming a material layer with a continuously varying thickness in the second through-hole 105.

[0050] 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 change in the second through-hole 105.

[0051] The parallel arrangement of the first control board 101 and the second control board 102 can reduce the risk of interference between the control component and the material source or the machine chamber, and facilitate debugging the thickness change trend of the material formed in the second through-hole 105.

[0052] The shape of the first through-hole includes a circle, an ellipse, a rectangle, a trapezoid or a polygon, and the number of side lengths of the polygon is greater than or equal to 5.

[0053] In this embodiment, the shape of the first through-hole includes a circle.

[0054] The shape of the second through-hole 105 includes a rectangle, a trapezoid or a polygon, and the number of side lengths of the polygon is greater than or equal to 5.

[0055] 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.

[0056] In another embodiment, the shape of the first through-hole is different from the shape of the second through-hole 105.

[0057] The material of the control component includes metal or metal alloy. The metal alloy includes stainless steel and iron-nickel alloy. The metal includes iron, aluminum or titanium.

[0058] The control component includes a first control board and a second control board, and an optical gradient structure is constructed within the second through-hole area of the second control board. This optical gradient structure includes at least two layers of materials, and the thickness of each layer can gradually increase or decrease. The refractive indices of adjacent layers of materials are different, forming a stacked optical structure. By controlling the control component, the thickness change of these multi-layer materials in different regions can be precisely controlled, thereby creating an optical gradient structure with a gradually changing thickness to achieve the desired 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. Second, this design can also optimize the appearance of the optical gradient structure. Since the thickness changes continuously, the problem of sudden thickness change is avoided, which not only improves the dimensional accuracy of the structure but also enhances the visual effect.

[0059] Figures 3 to 12 It is a schematic structural diagram of the preparation process of the multi-layer optical gradient structure in an embodiment of the present invention.

[0060] Please refer to Figure 3 and Figure 4 , Figure 3 is Figure 4 the top view of Figure 4 is Figure 3 the schematic cross-sectional structure of . A substrate 200 is provided, and the substrate 200 includes one or more grating structure regions 201.

[0061] The grating structure region 201 is the region for forming the subsequent material layer.

[0062] As Figure 3 shown, Figure 3 a single grating structure region 201 is shown, and a continuous region 20 is shown. The continuous region 20 includes two or more grating structure regions 201. Figure 3 In Figure 3 the continuous region 20 shows three different grating structure regions 201. The different grating structure regions 201 shown in the figure are only examples and do not constitute limitations on the structure and position of the grating structure region 201. For example, multiple grating structure regions 201 are independently separated, or divided into regions, or have other structural shapes, etc., which all belong to the grating structure region pointed out by the present invention.

[0063] The material of the substrate 200 includes inorganic materials or semiconductor materials. The inorganic materials include quartz, and the semiconductor materials include silicon, silicon carbide, titanium oxide, lithium niobate, germanium, gallium arsenide, etc.

[0064] Next, at least two target source materials are provided and disposed above the substrate 200; a control component as Figure 1 and Figure 2 described is provided, and the control component is disposed between the target source materials and the substrate 200, and the second control board 102 is adjacent to the substrate 200; at least two material layers with gradually increasing or decreasing thickness are formed on any region of the grating structure region by adjusting the positions of the target source materials relative to the first through-hole and the second through-hole 105.

[0065] In this embodiment, two material layers are formed on the grating structure region 201. For the process of forming two material layers, please refer to Figure 5 and Figure 6 .

[0066] Please continue to refer to Figure 2 , there is a first spacing H' between the first control board 101 and the second control board 102. The first through-hole has a first aperture diameter R1, and the second through-hole 105 has a second aperture diameter R2.

[0067] The first aperture diameter R1 is the maximum size of the first through-hole, and the second aperture diameter R2 is the maximum size of the second through-hole 105.

[0068] In this embodiment, the range of the first aperture diameter R1 is 6 mm to 10 mm.

[0069] In this embodiment, the range of the second aperture diameter R2 is 10 mm to 50 mm.

[0070] In this embodiment, the range of the first spacing H' is 25 mm to 35 mm.

[0071] In this embodiment, the first control board 101 has a first thickness d1, and the range of the first thickness d1 is 2 microns to 500 microns.

[0072] In this embodiment, the second control board 102 has a second thickness d2, and the range of the second thickness d2 is 2 microns to 500 microns.

[0073] 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.

[0074] In this embodiment, the second control board 102 is adjacent to the substrate 200, including: the second control board 102 is disposed on the substrate 200 and in contact with the substrate 200.

[0075] In other embodiments, the second control board is adjacent to the substrate, including: there is a spacing between the second control board and the substrate, and the second control board is not in direct contact with the substrate.

[0076] In this embodiment, the surface of the target source material is disposed 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.

[0077] Please refer to Figure 3 Continue to refer to 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.

[0078] 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 203 formed on the surface of the substrate 200.

[0079] The material of the material layer 203 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, aluminum oxide; the metal material includes one or a combination of more of copper, aluminum, tungsten, cobalt, nickel, and tantalum.

[0080] In this embodiment, it includes a first target source material 2021 and a second target source material 2022.

[0081] 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.

[0082] 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

[0083] Please refer to Figure 5 , using Figure 1 and Figure 2 the control components described above, by setting the relative positions of the first target source material 2021, the first through hole, and the second through hole 105, a first layer of material layer 2031 is formed in the second through hole 105 on the substrate 200.

[0084] 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. The thickness change trend of the first material layer 2031 is that 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 on the left side of the first material layer 2031 is large and the thickness on the right side is small.

[0085] Please refer to Figure 6 , and adopt Figure 1 and Figure 2 the control component described above. By setting the relative positions of the second target material 2022, the first through hole and the second through hole 105, a second material layer 2032 is formed on the first material layer 2031.

[0086] 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. The thickness change trend of the first material layer 2031 is that 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 first material layer 2031 gradually decreases, that is, the thickness on the right side of the first material layer 2031 is large and the thickness on the left side is small.

[0087] In this embodiment, the continuous thickness change trends of the first material layer 2031 and the second material layer 2032 are opposite. The continuous thickness change trends of the first material layer 2031 and the second material layer 2032 can cancel each other out, 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.

[0088] In other embodiments, the continuous thickness change trends of the first material layer and the second material layer can be the same.

[0089] In this embodiment, along the direction of the surface of the second control board 102, the second through hole 105 has opposite first and second sides, 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 (the first material layer 2031 and the second material layer 2032) with opposite thickness gradient trends are respectively formed.

[0090] 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.

[0091] 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.

[0092] When the first target source material 2021 and the second target source material 2022 are made of the same material, the refractive indexes of the first material layer 2031 and the second material layer 2032 are different by adjusting the process parameters during the formation of the material layers.

[0093] The specific process of adjusting the thickness of the material layer 203 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 Figure 9 , Figure 7 Schematic diagram of establishing a coordinate system based on the material layer 203. Figure 8 A schematic diagram of establishing a coordinate system for each structure based on the material layer 203, Figure 9 Schematic diagram of the coordinates of the relative positions of the target source material 202 , the first through hole and the second through hole 105 .

[0094] Please refer to Figure 7 , with the intersection of the thickest position of the material layer 203 and the substrate 200 as the coordinate origin O, a coordinate system (x, y) is established, where the horizontal coordinate x of the coordinate system (x, y) is the distance of the material layer 203 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 203 in a direction perpendicular to the surface of the substrate 200.

[0095] Please refer to Figure 8 , T(x,y) is the thickness of the material layer 203 at a certain position, and is a point in the target source material 202 , m(x, y) is any 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 .

[0096] In this embodiment, the height H between the first control board 101 and the substrate 200 is H′+d2, where 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.

[0097] 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 .

[0098] In other embodiments, the second control board is not in direct contact with the substrate, and the height H between the first control board and the substrate is H = H'+ d2 + the distance between the second control board and the substrate.

[0099] Please refer to Figure 9 , which is a point in the target source material 202. At both ends of the target source material 202, the point has the left and right critical coordinates for movement in the target source material 202 as , ; m(x, y) is an arbitrary point in the first through hole, and the critical coordinates for the movement of the point m(x, y) in the first through hole area are m(x1, y1) and m(x2, y2).

[0100] Please refer to Figure 10 , Figure 10 which is a schematic diagram based on Figure 9 . is a point in the target source material 202. At both ends of the target source material 202, the point has the left and right critical coordinates for movement in the target source material 202 as , ; m(x, y) is an arbitrary point in the first through hole, and the critical coordinates for the movement of the point m(x, y) in the first through hole area are m(x1, y1) and m(x2, y2); the critical coordinates for the movement in the second through hole 105 area are u(x1, y1) and u(x2, y2).

[0101] By adjusting the relative positions of the center line 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 with respect to the first through hole and the second through hole 105 are made to satisfy preset conditions, and the preset conditions include:

[0102]

[0103]

[0104]

[0105]

[0106] Among them, , respectively represent the left boundary critical coordinate values in the movement range of the target source material 202; , respectively represent the right boundary critical coordinate values in the movement range of the target source material 202; H is the distance between the first control board 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; is the left critical coordinate value on the x-axis in the first through-hole region, is the right critical coordinate value on the x-axis in the first through-hole region; is the left critical coordinate value on the y-axis in the first through-hole region, is the right critical coordinate value on the y-axis in the first through-hole region; is the left critical coordinate value on the x-axis in the second through-hole 105 region, is the left critical coordinate value on the y-axis in the second through-hole 105 region; is the right critical coordinate value on the x-axis in the second through-hole 105 region, is the right critical coordinate value on the y-axis in the second through-hole 105 region.

[0107] In the above formula, the relative positions of the target source material 202, the first through-hole, and the second through-hole 105 satisfy a preset condition, which can ensure that a material layer 203 with a continuously changing thickness is formed in the second through-hole 105.

[0108] In the direction from the center line of the first through-hole to the center line L2 of the second through-hole 105, the thickness of the material layer 203 gradually decreases. Specifically, in the direction from the center line of the first through-hole to the center line L2 of the second through-hole 105, the thickness of the material layer 203 in the second through-hole 105 continuously changes from 15 nanometers to 400 nanometers.

[0109] Please refer to Figure 11 , a patterned mask layer 210 is formed on the second material layer 2032.

[0110] Please refer to Figure 12 , using the patterned mask layer 210 as a mask to etch the second material layer 2032 and the first material layer 2031, an optical gradient structure is formed on the substrate 200, and 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 indices of the second optical layer 2062 on the first optical layer 2061 are different. In this embodiment, the required structure is formed by one etching, and the preparation process is simple and efficient.

[0111] Of course, in the embodiment of Figure 12 , only two optical layers are shown. In some other embodiments, such as in combination with Figure 16 , Figure 21 etc., there may also be three, four, or even more optical layers to form at least two optical layers with different refractive indices; in this regard, Figure 12 the embodiment of

[0112] 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 a material layer. The optical gradient structure has two optical layers with different refractive indices, and an optical gradient structure with a continuously varying thickness in multiple layers 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 this structure can also improve the display appearance of the optical gradient structure. By designing a continuous thickness gradient, the thickness mutation at different positions can be prevented, and such a design improves the dimensional accuracy and visual effect of the optical gradient structure.

[0113] In the forming method, by arranging the above control component between the target source material and the substrate, the second through-hole corresponds to the grating structure region, and the first through-hole corresponds to the target source material. By controlling the relative positions of the target source material, the first through-hole, and the second through-hole and the sputtering process, at least two material layers with sequentially increasing or decreasing thicknesses can be formed on any region of the grating structure region, and the display appearance of the optical gradient structure can be precisely controlled. In particular, there are no sudden change stripes easily appearing between different grating structure regions, and the thicknesses of different grating structure regions are continuously varying, thereby improving the display appearance of the formed optical gradient structure and modulating the diffraction efficiency of the optical gradient structure at different positions. Further, based on this method, a grating structure in a diffractive optical waveguide is formed, thereby forming a grating structure with a continuously varying depth. Different grating structures have different depths, and the gradient trends of multiple material layers are opposite, and the refractive indices of adjacent two layers of materials are different, thereby realizing the deposition of materials with different refractive indices. On the one hand, this method enables the diffraction efficiency of the prepared grating structure to be modulated at different positions. Based on the requirements of the diffraction efficiency, the refractive index of the deposited material and the refractive indices at different positions are selected, so that the grating structure has the selected refractive index at different positions, such as the continuously varying diffraction efficiency as defined, thereby improving the display uniformity of the diffractive optical waveguide and improving the display effect of the waveguide. On the other hand, based on the obtained diffractive optical waveguide, different grating structures have a continuously varying depth at different positions, which is different from the existing partition structure in terms of display appearance, so as to achieve a smooth transition of grating regions with different diffraction efficiencies, thereby preventing visual differences caused by thickness mutations at different positions and obtaining a better appearance effect visually.

[0114] Figure 13 and Figure 14 is a schematic structural diagram of a control component for preparing a multi-layer optical gradient structure in another embodiment of the present invention.

[0115] Please refer to Figure 13 and Figure 14 , Figure 13 is Figure 14Top view, Figure 14 is Figure 13 Schematic structural diagram along the direction of section line CC1, Figure 13 and Figure 14 The control component in Figure 1 and Figure 2 The difference between the control components in is that the number of the first through-holes is 3.

[0116] In this embodiment, the three first through-holes are respectively marked as 1041, 1042 and 1043, and the three first through-holes marked as 1041, 1042 and 1043 are arranged in an isosceles triangle or an equilateral triangle.

[0117] In this embodiment, the number of the second through-hole 105 is 1.

[0118] In other embodiments, the number of the second through-holes is two or more than two.

[0119] In other embodiments, when the second control board includes two second through-holes, one of the second through-holes corresponds to the turning grating structure region, and the other second through-hole corresponds to the coupling-out grating structure region, and the material layers corresponding to the turning grating structure and the coupling-out grating structure are simultaneously formed in the two second through-holes respectively.

[0120] In this embodiment, the projection range of each first through-hole on the second control board 102 partially overlaps with the projection range of the second through-hole 105 on the second control board 102. That is, the second through-hole 105 is arranged at the position of 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 a part of the second through-hole 105.

[0121] In other embodiments, the projection range of each first through-hole on the second control board does not overlap with the projection range of the second through-hole on the second control board.

[0122] In this embodiment, the apertures and areas of the three first through-holes can be the same or different.

[0123] Figure 15 and Figure 16 is a schematic structural diagram of the preparation process of a multi-layer optical gradient structure in another embodiment of the present invention.

[0124] In this embodiment, the optical gradient structure material layer includes three material layers with continuously changing thicknesses. The continuous change of the material layer thickness includes: gradually increasing thickness or gradually decreasing thickness.

[0125] In this embodiment, the continuous change trends of the thicknesses of adjacent two material layers are opposite.

[0126] In other embodiments, the continuous change trends of the thicknesses of adjacent two material layers can be the same.

[0127] Please refer to Figure 15 , and use Figure 13 and Figure 14 The control components in to form an optically graded structure material layer on the substrate 200. The optically graded 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.

[0128] For the formation process of the optically graded structure material layer, please refer to Figure 5 and to Figure 10 The process steps described therein will not be elaborated here.

[0129] In this embodiment, the continuous change trends of the thicknesses of adjacent two material layers are opposite. That is, the continuous change trends of the thicknesses of the first material layer 2031 and the second material layer 2032 are opposite, and the continuous change trends of the thicknesses of the second material layer 2032 and the third material layer 2033 are opposite. The continuous change trends of the thicknesses of the first material layer 2031 and the second material layer 2032 can cancel each other out, and the thickness change trend of the optically graded structure material layer is the same as the thickness change trend of the third material layer 2033.

[0130] In other embodiments, the continuous change trends of the thicknesses of two adjacent first material layers 2031, second material layers 2032 and third material layers 2033 can be the same.

[0131] In this embodiment, the refractive indices of adjacent two material layers are different. That is, the refractive indices of the materials of the first material layer 2031 and the second material layer 2032 are different, and the refractive indices of the materials of the second material layer 2032 and the third material layer 2033 are different.

[0132] 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, by adjusting the process parameters during the formation of the material layer, the refractive indices of the materials of the first material layer 2031 and the second material layer 2032 are made different.

[0133] The materials of the second material layer 2032 and the third material layer 2033 can be the same or different. When the materials of the second material layer 2032 and the third material layer 2033 are the same, by adjusting the process parameters during the formation of the material layer, the refractive indices of the second material layer 2032 and the third material layer 2033 are made different.

[0134] Please refer to Figure 16 , etch 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. 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 indices of adjacent two optical layers are different.

[0135] 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 please refer to Figure 11 and Figure 12 for the description, which will not be elaborated here.

[0136] 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 a material layer. The optical gradient structure has three optical layers with different refractive indices, and an optical gradient structure with a continuously varying thickness of multiple layers 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 this structure can also improve the display appearance of the optical gradient structure. By the design of continuously varying thickness, the thickness mutation at different positions can be prevented, and such a design improves the dimensional accuracy and visual effect of the optical gradient structure.

[0137] Figures 17 to 19 is a schematic structural diagram of a control component for preparing a multi-layer optical gradient structure in another embodiment of the present invention.

[0138] Please refer to Figures 17 to 19 , Figure 17 is Figure 18 and Figure 19 a top view of Figure 18 is Figure 17 a schematic structural diagram in the direction of the section line DD1, Figure 19 is Figure 17 a schematic structural diagram in the direction of the section line EE1, Figures 17 to 19 The difference between the control component in Figure 1 and Figure 2 is that the number of the first through-holes is 4.

[0139] In this embodiment, the four first through-holes are respectively 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.

[0140] In this embodiment, the number of the second through-holes 105 is one.

[0141] In other embodiments, the number of the second through-holes is two or more.

[0142] In other embodiments, when the second control board includes two second through-holes, one of the second through-holes corresponds to the turning grating structure region, and the other second through-hole corresponds to the coupling-out grating structure region. The material layers corresponding to the turning grating structure and the coupling-out grating structure are simultaneously formed in the two second through-holes respectively.

[0143] In this embodiment, the projection range of each first through-hole on the second control board 102 partially overlaps with the projection range of the second through-hole 105 on the second control board 102. That is, the second through-hole 105 is arranged at the center of the rectangle formed by the four first through-holes marked as 1041, 1042, 1043, and 1044 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.

[0144] In other embodiments, the projection range of each first through-hole on the second control board does not overlap with the projection range of the second through-hole on the second control board.

[0145] In this embodiment, the apertures and areas of the four first through-holes can be the same or different.

[0146] Figure 20 and Figure 21 is a schematic structural diagram of the preparation process of a multi-layer optical gradient structure in another embodiment of the present invention.

[0147] In this embodiment, the optical gradient structure material layer includes four material layers with continuously changing thicknesses. The thickness of the material layer changes continuously, including: gradually increasing in thickness, or gradually decreasing in thickness.

[0148] In this embodiment, the continuous change trends of the thicknesses of adjacent two material layers are opposite.

[0149] In other embodiments, the continuous change trends of the thicknesses of adjacent two material layers can be the same.

[0150] Please refer to Figure 20 , and use the control component in Figures 17 to 19 to form an optically graded structure material layer on the substrate 200. The optically graded structure material layer includes a first layer material layer 2031, a second layer material layer 2032 located on the first layer material layer 2031, a third layer material layer 2033 located on the second layer material layer 2032, and a fourth layer material layer 2034 located on the third layer material layer 2033.

[0151] For the formation process of the optically graded structure material layer, please refer to Figure 5 and from Figure 10 for the process steps, which will not be elaborated here.

[0152] In this embodiment, the thickness continuous change trends of adjacent two-layer material layers are opposite. That is, the thickness continuous change trends of the first layer material layer 2031 and the second layer material layer 2032 are opposite, the thickness continuous change trends of the second layer material layer 2032 and the third layer material layer 2033 are opposite, and the thickness continuous change trends of the third layer material layer 2033 and the fourth layer material layer 2034 are opposite. The thickness continuous change trends of the first layer material layer 2031 and the second layer material layer 2032 can cancel each other out, and the thickness continuous change trends of the third layer material layer 2033 and the fourth layer material layer 2034 can cancel each other out. The thickness of the optically graded structure material layer is uniform.

[0153] In other embodiments of the present invention, the thickness continuous change trends of adjacent two of the first layer material layer 2031, the second layer material layer 2032, the third layer material layer 2033, and the fourth layer material layer 2034 can be the same.

[0154] In this embodiment, the refractive indices of adjacent two-layer material layers are different. That is, the refractive indices of the materials of the first layer material layer 2031 and the second layer material layer 2032 are different, the refractive indices of the materials of the second layer material layer 2032 and the third layer material layer 2033 are different, and the refractive indices of the materials of the third layer material layer 2033 and the fourth layer material layer 2034 are different.

[0155] The materials of the first layer material layer 2031 and the second layer material layer 2032 can be the same or different. When the materials of the first layer material layer 2031 and the second layer material layer 2032 are the same, by adjusting the process parameters during the formation of the material layer, the refractive indices of the materials of the first layer material layer 2031 and the second layer material layer 2032 are made different.

[0156] The materials of the second material layer 2032 and the third material layer 2033 can 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 indices of the second material layer 2032 and the third material layer 2033 are made different by adjusting the process parameters during the formation of the material layer.

[0157] 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 indices of the third material layer 2033 and the fourth material layer 2034 are made different by adjusting the process parameters during the formation of the material layer.

[0158] Please refer to Figure 21 , etch 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. The optical gradient structure includes 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 indices of adjacent two optical layers are different.

[0159] 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 please refer to Figure 19 and Figure 20 for the description, which will not be elaborated here.

[0160] 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 the material layer. The optical gradient structure has four optical layers with different refractive indices, and an optical gradient structure with a continuously changing thickness of multiple layers 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 this structure can also improve the display appearance of the optical gradient structure. By the design of continuously changing thickness, the thickness mutation at different positions can be prevented, and such a design improves the dimensional accuracy and visual effect of the optical gradient structure.

[0161] In another embodiment, a grating structure is provided within the grating structure region on the surface of the substrate. A plurality of the grating structures are discrete on the substrate, and the heights of the plurality of the grating structures are the same. A plurality of material layers are located on the sidewall surfaces and the top surfaces of the grating structures. Along the arrangement direction of the plurality of the grating structures, the thicknesses of the material layers located on the sidewall surfaces and the top surfaces of the grating structures gradually increase or gradually decrease.

[0162] In another embodiment, a grating structure is provided within the grating structure region of the substrate. The substrate and the grating structure within the substrate have a flat surface, that is, the tops of the plurality of the grating structures are flush with the top of the substrate. A plurality of material layers are located on the sidewall surfaces and the top surfaces of the grating structures. Along the arrangement direction of the plurality of the grating structures, the thicknesses of the material layers located on the sidewall surfaces and the top surfaces of the grating structures gradually increase or gradually decrease.

[0163] In another embodiment, a method for fabricating a multi-layer optical gradient structure includes: forming a first layer of material layers with sequentially increasing or decreasing thicknesses on the grating structure region; etching the first layer of material layers to form a first layer of grating structures based on the first layer of material layers; forming a second layer of material layers with sequentially increasing or decreasing thicknesses on the surface of the first layer of grating structures; etching the second layer of material layers and forming a second layer of grating structures based on the second layer of material layers, and continuing to form material layers on the second layer of grating structures; 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 grating structures can be controlled, and there is a large degree of design freedom.

[0164] 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 should be subject to the scope defined by the claims.

Claims

1. A method for preparing a multilayer optical gradient structure, characterized in that: include: providing a substrate comprising one or more grating structure regions; providing at least two target source materials, disposed above the substrate; A control assembly is provided and placed between the target source material and the substrate and in contact with the surface of the substrate, the control assembly comprising: a first control plate and a second control plate with a preset spacing; the first control plate comprising at least two first through holes, the second control plate comprising at least one second through hole, the center lines of at least two first through holes and at least one second through hole not overlapping, and the projection range of the first through hole onto the second control plate partially overlapping the range of the second through hole; the control assembly is configured to deposit the multilayer optical gradient structure in the second through hole, the multilayer optical gradient structure comprising at least two material layers with opposite thickness variation trends, the materials sequentially passing through the first through hole and the second through hole when depositing to form the material layers; Forming two material layers with opposite thickness gradient trends on any region 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; The relative position of the target source material with respect to the first through hole and the second through hole satisfies a preset condition, wherein the preset condition includes: ， in, 、 They represent the critical coordinate values of the left boundary of the target source material's active range; 、 They represent the critical coordinate values of the right boundary of the target source material's active range; is the distance between the first control board and the base plate; is the distance from the center of the target material to the substrate surface; In the first through hole region The left critical coordinate value of the axis, In the first through hole region The right critical coordinate value of the axis; In the first through hole region The left critical coordinate value of the axis, In the first through hole region The right critical coordinate value of the axis; In the second through hole area The left critical coordinate value of the axis, In the second through hole area The left critical coordinate value of the axis; In the second through hole area The right critical coordinate value of the axis, In the second through hole area The right critical coordinate value of the axis.

2. The method for preparing a multilayer optical gradient structure according to claim 1, wherein: 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 with successively increasing or decreasing thicknesses are formed in the grating structure region to form a multi-layer optical gradient grating structure on the material layer.

3. The method for preparing a multilayer optical gradient structure according to claim 1, wherein: 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.

4. The method for preparing a multilayer optical gradient structure according to claim 1, wherein: 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. 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.

5. The method for preparing a multilayer optical gradient structure according to claim 4, wherein: The refractive indices of two adjacent material layers are different.

6. The method for preparing a multilayer optical gradient structure according to claim 3, wherein: The second control plate includes two second through holes, one of which corresponds to the turning grating structure area, and the other second through hole corresponds to the outcoupling grating structure area, and the material layers corresponding to the turning grating structure and the outcoupling grating structure are formed simultaneously in the two second through holes.

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