Nanoimprint master, optical waveguide and method of manufacturing the same

Abstract

The present invention provides a nanoimprint master, an optical waveguide, and a method for manufacturing the same. The nanoimprint master includes a lattice structure region, a non-lattice structure region surrounding the lattice structure region, and a depressed structure. The depressed structure is disposed in the non-lattice structure region adjacent to the lattice structure region, and extends along the circumferential direction of the lattice structure region so as to surround the lattice structure region.

Description

[Technical Field]

[0001] <Cross-reference to related patent applications> This application claims priority from a Chinese patent application filed on August 31, 2023, bearing application number 202311118170.5 and entitled "Nanoimprint master, optical waveguide and manufacturing method thereof," the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to the technical field of nanoimprinting, and more particularly to a nanoimprint master, an optical waveguide, and a method for manufacturing the same. [Background technology]

[0003] Nanoimprinting is a new micro- and nano-fabrication technology that transfers micro- and nano-image structures onto a corresponding substrate via a template. It overcomes the feature size reduction problems inherent in traditional photolithography, enabling feature sizes to reach the nanometer scale, offering the advantages of high resolution and low cost. With the development and sophistication of the AR / VR industry, the nanoimprinting process for optical waveguide products has gradually become industrialized. However, there are still some process challenges associated with the fabrication of optical waveguide products using nanoimprinting. The edges of the lattice structure area of ​​nanoimprinted products have a large height difference between the lattice structure area and the non-lattice structure area, which prevents the subplate from fitting snugly to the substrate, resulting in defects such as poor edge alignment of the lattice structure area and uneven adhesive residue. This significantly impacts the performance of optical waveguide displays.

[0004] Each embodiment of the present invention provides a nanoimprint master, an optical waveguide, and a method for manufacturing the same.

[0005] In one aspect, the present invention provides a nanoimprint master, the nanoimprint master including a lattice structure region, a non-lattice structure region surrounding the lattice structure region, and a depressed structure, the depressed structure being disposed in the non-lattice structure region adjacent to the lattice structure region, and the depressed structure extending along the circumferential direction of the lattice structure region so as to surround the lattice structure region.

[0006] The distance between the inner edge of the sunken structure and the outer edge of the lattice structure region is 0.01 μm to 1000 μm.

[0007] The processing width of the recessed structure is 0.01 μm or more.

[0008] The recessed structure has a processing depth of 0.01 μm to 100 μm.

[0009] The recessed structure includes a single annular groove recessed from the surface of the non-lattice structure region.

[0010] The groove depth of the annular groove is equal to the theoretical depth ΔH of the recessed structure.

[0011] The theoretical depth of the recessed structure satisfies ΔH=H1*(1-L / P), where H1 is the lattice height of the lattice structure region, L is the lattice line width of the lattice structure region, and P is the lattice period of the lattice structure region.

[0012] The recessed structure includes a plurality of annular grooves recessed from the surface of the non-lattice structure region and connected to each other, and the groove depths of the annular grooves decrease sequentially from the inside to the outside, forming stepped grooves.

[0013] The difference between the groove depths of two adjacent annular grooves is equal to the allowable depth of the sub-plate, and the allowable depth Δh of the sub-plate is determined by the material and thickness of the sub-plate.

[0014] The number N of the annular grooves satisfies the relationship N=ROUNDUP(ΔH / Δh), where ROUNDUP is the ceiling function, ΔH is the theoretical depth of the recessed structure, and Δh is the allowable depth of the sub-plate.

[0015] In a second aspect, the present invention provides an optical waveguide, which includes a waveguide substrate and a coupling grating, and the coupling grating is formed on the waveguide substrate by nanoimprinting using any of the nanoimprint masters described above.

[0016] In a third aspect, the present invention provides a method for manufacturing a nanoimprint master, which includes step S100 of calculating a theoretical depth ΔH of a recessed structure ΔH=H1*(1-L / P) based on the grating height H1, grating line width L, and grating period P of a grating structure region, step S200 of calculating an allowable depth Δh of the sub-plate based on the material and thickness of the sub-plate, step S300 of comparing the allowable depth Δh of the sub-plate with the theoretical depth ΔH of the recessed structure, step S400 of not installing a recessed structure at a position adjacent to the grating structure region in the non-grating structure region if Δh≧ΔH, or etching the position adjacent to the grating structure region in the non-grating structure region to form a single annular groove, where the groove depth of the annular groove is equal to the theoretical depth of the recessed structure, and step S500 of installing a recessed structure at a position adjacent to the grating structure region in the non-grating structure region if Δh<ΔH.

[0017] Step S500 includes sub-step S510 of rounding down ΔH / Δh to obtain a number N of annular grooves in the sunken structure, where N is a positive integer greater than 1; and sub-step S520 of etching the non-lattice structure region at a position adjacent to the lattice structure region to form N annular grooves.

[0018] Step S500 includes the following substeps: substep S510': adjusting the material and thickness of the sub-plate to improve the allowable depth of the sub-plate to obtain an improved allowable depth Δh' of the sub-plate; substep S520': if Δh'≧ΔH, not providing the recessed structure at a position adjacent to the lattice structure region in the non-lattice structure region, or etching the position adjacent to the lattice structure region in the non-lattice structure region to form a single annular groove, where the groove depth of the annular groove is equal to the theoretical depth of the recessed structure; substep S530': if Δh'<ΔH, rounding down ΔH / Δh' to obtain the number N of annular grooves of the recessed structure, where N is a positive integer; and substep S540': etching the position adjacent to the lattice structure region in the non-lattice structure region to form N annular grooves.

[0019] When N=1, the groove depth of the annular groove is equal to the theoretical depth of the sinking structure; when N≧2, the multiple annular grooves are connected, the groove depths of the multiple annular grooves decrease sequentially from the inside to the outside, and the difference in groove depth between two adjacent annular grooves is equal to the allowable depth of the sub-plate.

[0020] In a fourth aspect, the present invention provides a method for manufacturing an optical waveguide, the method comprising the steps of: manufacturing a nanoimprint master by any of the nanoimprint master manufacturing methods described above; imprinting a subplate substrate using the nanoimprint master and curing the substrate to form a nanoimprint subplate; and imprinting a waveguide substrate using the nanoimprint subplate and curing the substrate to form an optical waveguide.

[0021] The details of one or more embodiments of the invention are set forth in the drawings and description that follow to make other features, objects and advantages of the invention more concise and easy to understand. [Brief explanation of the drawings]

[0022] In order to more clearly describe the embodiments of the present invention or the technical solutions in the prior art, the drawings necessary for describing the embodiments or the prior art are briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present invention, and those skilled in the art can obtain other drawings based on the disclosed drawings without any creative efforts.

[0023] [Figure 1] 1A and 1B illustrate the structure of a nanoimprint master according to one embodiment of the present invention. [Figure 2] 1A and 1B show a first example of a nanoimprint master according to the above embodiment of the present invention; [Figure 3] FIG. 3 shows an enlarged view of a local area S of the nanoimprint master of FIG. 2. [Figure 4] FIG. 2 shows a second example of a nanoimprint master according to the above embodiment of the present invention. [Figure 5] 1 is a flowchart of a method for manufacturing a nanoimprint master according to one embodiment of the present invention. [Figure 6] FIG. 10 is a diagram showing a first example of step S500 in the method for manufacturing a nanoimprint master according to the embodiment of the present invention. [Figure 7] FIG. 10 is a diagram showing a second example of step S500 in the method for manufacturing a nanoimprint master according to the embodiment of the present invention. [Figure 8] 1A and 1B are diagrams showing the structure of an optical waveguide according to one embodiment of the present invention; [Figure 9] 1 is a flowchart of a method for manufacturing an optical waveguide according to an embodiment of the present invention. [Figure 10] 5A to 5C are diagrams illustrating an example of a method for manufacturing an optical waveguide according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] The following clearly and completely describes the technical solutions of the embodiments of the present invention in combination with the drawings of the embodiments of the present invention, but it is obvious that the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0025] Those skilled in the art will understand that in the content of the present disclosure, orientations and positional relationships indicated by terms such as "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," etc. are based on the orientations and positional relationships shown in the drawings, and are used only to facilitate and simplify the description of the present invention, and do not indicate or imply that the designated devices or elements must have a particular orientation or be constructed or operated in a particular orientation, and therefore the above terms should not be construed as limitations on the present invention.

[0026] In the present invention, the term "one" in the claims and the description of the specification shall be understood as "one or more." That is, in one embodiment, the quantity of an element may be one, and in another embodiment, the quantity of an element may be more than one. Unless the disclosure of the present invention explicitly indicates that the quantity of an element is only one, otherwise, the term "one" cannot be understood as unique or singular, and cannot be understood as limiting the quantity.

[0027] Furthermore, in the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or the quantity of the technical features shown. In the description of the present invention, unless otherwise specified or limited, "connected" and "coupled" should be understood in a broad sense, for example, they may be fixedly connected, detachably connected, integrally connected, mechanically connected, or electrically connected, and may be directly connected or indirectly connected via a medium. Those skilled in the art should understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0028] In describing the present invention, terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" mean that the specific features, structures, or materials described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In the specification of the present invention, schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, or materials described can be combined in any appropriate manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described herein, as long as they are not mutually inconsistent.

[0029] In analyzing the nanoimprinting process, the applicant discovered that the main reasons for defects such as defective edges of the lattice structure region and uneven residual adhesive are as follows: When the subplate imprints the product, the height difference between the top of the lattice in the lattice structure region and the top of the adhesive in the non-lattice structure region is large, and the adhesive layer of the product is thin. This prevents the subplate from fitting tightly to the substrate around the lattice structure region, resulting in defective edges and the formation of a ring-shaped defect zone. This has a significant impact on the appearance of the product and the performance of the optical display. During the nanoimprinting and fitting process, the subplate at the edge of the lattice structure region is recessed and deformed, preventing the adhesive at the edge of the lattice structure region from being completely filled, resulting in the defect of uneven residual adhesive, which further affects the performance of the optical display.

[0030] To solve this problem, the present invention uniquely provides a nanoimprint master, an optical waveguide, and a method for manufacturing the same, which can solve the problems of poor edge of the grating structure region and uneven residual adhesive in the nanoimprint process, thereby improving the performance of optical displays and improving the appearance of products.

[0031] 1 to 4 of the accompanying drawings, one embodiment of the present invention provides a nanoimprint master 10. The nanoimprint master 10 includes a lattice structure region 11, a non-lattice structure region 12 located around the lattice structure region 11, and a depressed structure 13. The depressed structure 13 is located at a position adjacent to the lattice structure region 11 in the non-lattice structure region 12, and extends along the circumferential direction of the lattice structure region 11 so as to surround the lattice structure region 11.

[0032] More specifically, as shown in FIGS. 2 and 4, the nanoimprint master 10 of the present invention may have one or more lattice structure regions 11. In this case, the nanoimprint master 10 needs to have a corresponding number of recessed structures 13, and the recessed structures 13 surround the lattice structure regions 11 one-to-one. For example, the nanoimprint master 10 may include a coupling-in lattice structure region 111 and a coupling-out lattice structure region 112 spaced apart. In this case, the nanoimprint master 10 needs to undergo a recession process around the coupling-in lattice structure region 111 and the coupling-out lattice structure region 112, respectively, to obtain a coupling-in recessed structure 131 surrounding the coupling-in lattice structure region 111 and a coupling-out recessed structure 132 surrounding the coupling-out lattice structure region 112, thereby ensuring that both the coupling-in lattice and the coupling-out lattice created by imprint transfer are free from problems such as defective edges and uneven residual adhesive.

[0033] In addition, since a sunken structure 13 surrounding the lattice structure region 11 is provided in the non-lattice structure region 12 of the nanoimprint master 10 at a position adjacent to the lattice structure region 11, the difference in height between the top of the grating imprinted by the nanoimprint master 10 and the top of the adhesive layer in the non-lattice structure region is reduced. This reduces or eliminates defects such as poor edges in the lattice structure region and uneven residual adhesive caused by an excessively large difference in height.

[0034] 3, in order to protect the lattice structure in the lattice structure region 11, the distance A between the inner edge of the recessed structure 13 and the outer edge of the lattice structure region 11 is 0.01 μm to 1000 μm. It can be understood that the distance A mentioned in the present invention can be adjusted according to factors such as the filling characteristics of the material of the sub-plate and the thickness of the sub-plate, which will not be described again in the present invention.

[0035] 3, in order to avoid the problem of poor annular shape caused by the processing width B of the recessed structure 13 being too small, the processing width B of the recessed structure 13 may be 0.01 μm or more. It can be understood that the processing width B mentioned in the present invention is related to the rigidity of the material of the sub-plate, and the higher the rigidity of the material of the sub-plate, the larger the required processing width B.

[0036] Furthermore, the processing width B of the sinking structure 13 may be equal to or less than the width of the non-lattice structure region 12, i.e., the sinking structure 13 can at most cover the entire non-lattice structure region 12. The processing width B of the sinking structure 13 is usually 30 cm or less.

[0037] To ensure that the sub-plate adheres tightly to the imprint substrate (eg, a waveguide substrate), the recessed structure 13 may have a processing depth between 0.01 μm and 100 μm.

[0038] It is worth noting that, as shown in Figure 3, the processing depth of the recessed structure 13 can be set by the theoretical depth ΔH of the recessed structure 13, which can be calculated by the lattice height H1 of the actual product, the thickness of the residual adhesive H2, and the imprint thickness H3 of the non-lattice structure area, and the following relationship is satisfied: ΔH = H1 + H2 - H3, H1 * L + P * H2 = H3 * P, where L is the lattice line width of the lattice structure area 11, and P is the lattice period of the lattice structure area 11.

[0039] From the analysis, it can be seen that the theoretical depth ΔH of the subsidence structure 13 satisfies the relationship ΔH=H1*(1-L / P), where H1 is the lattice height of the lattice structure region 11, L is the lattice line width of the lattice structure region 11, and P is the lattice period of the lattice structure region 11.

[0040] It can be seen that the sum of the lattice height of the lattice structure region and the thickness of the residual adhesive region in an actual product is greater than the imprint thickness of the non-lattice structure region. In the present invention, the difference between the sum of the lattice height of the lattice structure region and the thickness of the residual adhesive region and the imprint thickness of the non-lattice structure region is defined as the theoretical depth ΔH of the recessed structure 13. The theoretical depth ΔH of the recessed structure 13 and the allowable depth Δh of the subplate determine whether a ring defect occurs, and the allowable depth Δh of the subplate is determined by the material / quality of the subplate. If the allowable depth Δh of the subplate is equal to or greater than the theoretical depth ΔH of the recessed structure 13, a ring defect will not occur even without the recessed structure. If the allowable depth Δh of the subplate is less than the theoretical depth ΔH of the recessed structure 13, a recessed structure is required to prevent a ring defect.

[0041] In addition, to further improve the problem of uneven residual adhesive, even if the allowable depth Δh of the sub-plate is greater than or equal to the theoretical depth ΔH of the sinking structure 13, the nanoimprint master 10 of the present invention may still have the sinking structure 13 installed.

[0042] For example, in the first embodiment of the present invention, as shown in Figures 2 and 3, the recessed structure 13 may include a single annular groove 130 recessed from the surface of the non-lattice structure area 12 so as to surround the lattice structure area 11, thereby creating a buffer between the height of the top of the imprinted lattice and the height of the top of the adhesive layer in the non-lattice structure area, thereby avoiding defects caused by the subplate not contacting the imprinted substrate due to an excessively large height difference, such as problems such as uneven residual adhesive at the edge of the lattice structure area.

[0043] 3, the groove depth of the annular groove 130 may be equal to the theoretical depth ΔH of the sinking structure 13. It is understood that in other examples of the present invention, the groove depth of the annular groove 130 may be greater than the theoretical depth ΔH, as long as it does not exceed the allowable depth Δh of the sub-plate.

[0044] If the allowable depth Δh of the sub-plate is smaller than the theoretical depth ΔH of the recessed structure 13, and the recessed structure 13 includes only a single annular groove, the groove depth of this annular groove will be greater than the allowable depth Δh of the sub-plate, and the problem of annular defects will still occur. Therefore, in a second embodiment of the present invention, as shown in Figure 4, the recessed structure 13 may include multiple annular grooves 130 recessed from the surface of the non-lattice structure region 12 and connected to each other. The groove depths of the multiple annular grooves 130 decrease sequentially from the inside to the outside, forming stepped grooves, which helps to solve the problem of annular defects caused by excessively deep groove depths.

[0045] As shown in FIG. 4, the difference in groove depth between two adjacent annular grooves 130 may be equal to the allowable depth Δh of the sub-plate, which can prevent the defect problem of annular defects caused by the difference in groove depth between two adjacent annular grooves 130 being greater than the allowable depth Δh of the sub-plate.

[0046] The number N of the annular grooves 130 satisfies the relationship N = ROUNDUP (ΔH / Δh), where ROUNDUP is the ceiling function, ΔH is the theoretical depth of the recessed structure, and Δh is the allowable depth of the sub-plate. Thus, the number N referred to in the present invention is a positive integer greater than 1. For example, when ΔH / Δh = 1.2, N = 2, and when ΔH / Δh = 2.5, N = 3, ensuring that the difference in groove depth between two adjacent annular grooves 130 is less than the allowable depth Δh of the sub-plate.

[0047] In summary, the sunken structure 13 referred to in the present invention may be, but is not limited to, one or more annular grooves 130 formed in the non-lattice structure region 12 by etching. The annular shape referred to in the present invention is not limited to a circular ring, but may be a rectangular ring or other type of ring structure as long as it matches the shape of the lattice structure region 11, which will not be described in detail in the present invention.

[0048] In a second aspect, one embodiment of the present invention further provides a method for manufacturing a nanoimprint master, as shown in Figure 5. The method for manufacturing a nanoimprint master includes the following steps:

[0049] Step S100: Based on the grid height H1, grid line width L and grid period P of the grid structure area, calculate the theoretical depth ΔH=H1*(1−L / P) of the subsidence structure.

[0050] Step S200: The allowable depth Δh of the sub-plate is calculated based on the material and thickness of the sub-plate.

[0051] Step S300: The allowable depth Δh of the subplate is compared with the theoretical depth ΔH of the subsidence structure.

[0052] Step S400: If Δh≧ΔH, do not install a recessed structure at the position adjacent to the lattice structure region in the non-lattice structure region, or etch the position adjacent to the lattice structure region in the non-lattice structure region to form a single annular groove, where the groove depth of the annular groove is equal to the theoretical depth of the recessed structure.

[0053] Step S500: If Δh<ΔH, a subsidence structure is installed in a non-lattice structure region at a position adjacent to the lattice structure region.

[0054] In step S400, if Δh≧ΔH, it is possible to provide no sinking structure or to provide a single annular groove, both of which can avoid the problem of defective annular shape.

[0055] In the first example of the present invention, as shown in FIG. 6, step S500 includes the following substeps:

[0056] Substep S510: Round up ΔH / Δh to obtain the number N of annular grooves of the subsidence structure, where N is a positive integer greater than 1.

[0057] Substep S520: Etching is performed in the non-lattice structure region at a position adjacent to the lattice structure region to form N interconnected annular grooves, where the groove depths of the N annular grooves decrease sequentially from the inside to the outside, and the difference in groove depth between two adjacent annular grooves is equal to the allowable depth of the sub-plate.

[0058] The allowable depth Δh of the sub-plate is determined by the material and thickness of the sub-plate. Therefore, in the present invention, the allowable depth of the sub-plate can be improved by adjusting the material (e.g., adhesive type) and / or thickness of the sub-plate, resulting in an allowable improved depth Δh' of the sub-plate that is greater than the allowable depth Δh. If the allowable improved depth Δh' of the sub-plate is greater than the theoretical depth ΔH of the subsidence structure, then the subsidence structure is not required, or a single annular groove can be provided to solve the annular defect problem. If the allowable improved depth Δh' of the sub-plate is still smaller than the theoretical depth ΔH of the subsidence structure, then multiple annular grooves must be provided to form a stepped groove to solve the annular defect problem.

[0059] For example, in the second embodiment of the present invention, as shown in FIG. 7, step S500 includes the following substeps:

[0060] Sub-step S510': Adjust the material of the sub-plate and the thickness of the sub-plate to improve the allowable depth of the sub-plate, and obtain the allowable improved depth Δh' of the sub-plate.

[0061] Substep S520': If Δh'≧ΔH, then either no recessed structure is provided in the non-lattice structure region adjacent to the lattice structure region, or the non-lattice structure region adjacent to the lattice structure region is etched to form a single annular groove, where the groove depth of the annular groove is equal to the theoretical depth of the recessed structure.

[0062] Substep S530': If Δh'<ΔH, round up ΔH / Δh' to obtain the number N of annular grooves of the sinking structure, where N is a positive integer greater than 1.

[0063] Substep S540': Etching is performed in the non-lattice structure region at a position adjacent to the lattice structure region to form N interconnected annular grooves, where the groove depths of the N annular grooves decrease sequentially from the inside to the outside, and the difference in groove depth between two adjacent annular grooves is equal to the allowable depth of the sub-plate.

[0064] Thirdly, as shown in Figure 8, one embodiment of the present invention further provides an optical waveguide 20. The optical waveguide 20 includes a waveguide substrate 21 and a coupling grating 22. The coupling grating 22 is formed on the waveguide substrate 21 by nanoimprinting using the nanoimprint master 10, so that the grating teeth at the edge of the coupling grating 22 have a better repair effect, reducing or eliminating the problems of edge defects and uneven residual adhesive.

[0065] 8, the coupling grating 22 includes a coupling-in grating 221 and a coupling-out grating 222 spaced apart on the waveguide substrate 21, and the coupling-in grating 221 and the coupling-out grating 222 correspond to the coupling-in grating structure region 112 and the coupling-out grating structure region 112 of the nanoimprint master 10, respectively. It can be understood that the coupling grating 22 referred to in the present invention may also be a pupil expansion grating (not shown) located in the optical path between the coupling-in grating 221 and the coupling-out grating 222. Thus, the nanoimprint master 10 is also provided with a pupil expansion grating structure region corresponding to the pupil expansion grating, which will not be described in detail in the present invention.

[0066] In a fourth aspect, an embodiment of the present invention further provides a method for manufacturing an optical waveguide, as shown in Figure 9. The method for manufacturing an optical waveguide includes the following steps:

[0067] A nanoimprint master 10 is manufactured by the nanoimprint master manufacturing method.

[0068] The nanoimprint master 10 is used to imprint a subplate substrate 300, which after curing forms a nanoimprint subplate 30.

[0069] The waveguide substrate 21 is imprinted using the nanoimprint subplate 30, and after curing, the optical waveguide 20 is formed.

[0070] 10, the subplate substrate 300 referred to in the present invention is composed of a subplate base 31 and a subplate adhesive 32 applied to the surface of the subplate base 31. The nanoimprint master 10 imprints the subplate adhesive 32 on the subplate substrate 300, and after the subplate adhesive 32 is cured, a nanoimprint subplate 30 can be obtained.

[0071] 10, the waveguide substrate 21 referred to in the present invention is composed of a waveguide base 211 and a waveguide adhesive 212 applied to the surface of the waveguide base 211 before curing. The nanoimprint subplate 30 imprints the waveguide adhesive 212 on the waveguide substrate 21, and after the waveguide adhesive 212 is cured, the optical waveguide 20 can be obtained.

[0072] For the sake of simplicity, we will not describe all possible combinations of the technical features of the above embodiments, but as long as there is no contradiction in the combination of these technical features, they can be combined. All possible combinations should be used and are considered to be within the scope of this manual.

[0073] The above embodiments only represent some embodiments of the present invention, and although the descriptions thereof are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make some modifications and improvements without departing from the concept of the present invention, all of which fall within the protection scope of the present invention.

[0074] The technical features of the above-described embodiments can be combined in any manner. For the sake of brevity, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as the combinations of these technical features are not contradictory, they should all be considered to be within the scope of the present specification.

[0075] The above-mentioned embodiments only represent some embodiments of the present invention, and although the description is relatively specific and detailed, it should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make some variations and modifications without departing from the spirit and scope of the present invention, and they all belong to the protection scope of the present invention. [Explanation of symbols]

[0076] 10 Nanoimprint Master 11 Lattice structure region 111 Coupling-in lattice structure domain 112 Coupling-out lattice structure domain 12 Non-lattice structure region 13 Subsidence structure 130 Annular groove 131 Coupling-in subsidence structure 132 Coupling-out subsidence structure 20 Optical waveguide 21 Waveguide substrate 211 Waveguide Base 212 Waveguide Adhesive 22 Coupling lattice 221 Coupling-in lattice 222 Coupling-out lattice 30 Nanoimprint Subplate 300 Subplate board 31 Subplate base 32 Subplate adhesive

Claims

1. The nanoimprint master includes a lattice structure region, a non-lattice structure region located around the lattice structure region, and a sunken structure, wherein the sunken structure is positioned adjacent to the lattice structure region in the non-lattice structure region, and the sunken structure extends along the circumferential direction of the lattice structure region so as to surround the lattice structure region.

2. The nanoimprint master according to claim 1 , wherein the distance between the inner edge of the recessed structure and the outer edge of the lattice structure region is 0.01 μm to 1000 μm.

3. The nanoimprint master according to claim 1 , wherein the recessed structure has a processing width of 0.01 μm or more.

4. 2. The nanoimprint master according to claim 1, wherein the recessed structure has a processing depth of 0.01 μm to 100 μm.

5. A nanoimprint master according to any one of claims 1 to 4, characterized in that the recessed structure comprises a single annular groove recessed from the surface of the non-grating structure region.

6. The nanoimprint master of claim 5 , wherein the groove depth of the annular groove is equal to the theoretical depth ΔH of the recessed structure.

7. The theoretical depth of the sinking structure ΔH=H １ * (1-L / P) is satisfied, where H １ 7. The nanoimprint master according to claim 6, wherein: is a grating height of the grating structure region; L is a grating line width of the grating structure region; and P is a grating period of the grating structure region.

8. The nanoimprint master of any one of claims 1 to 4, characterized in that the sunken structure includes a plurality of annular grooves recessed from the surface of the non-lattice structure region and connected to each other, and the groove depths of the plurality of annular grooves decrease sequentially from the inside to the outside, forming stepped grooves.

9. The nanoimprint master of claim 8, characterized in that the difference in groove depth between two adjacent annular grooves is equal to the allowable depth of the subplate, and the allowable depth Δh of the subplate is determined by the material and thickness of the subplate.

10. 9. The nanoimprint master of claim 8, wherein the number N of the annular grooves satisfies the relationship N=ROUNDUP(ΔH / Δh), where ROUNDUP is a ceiling function, ΔH is the theoretical depth of the recessed structure, and Δh is the allowable depth of the sub-plate.

11. The optical waveguide includes a waveguide substrate and a coupling grating, and the coupling grating is formed on the waveguide substrate by nanoimprinting using the nanoimprint master according to any one of claims 1 to 10.

12. Lattice height H of the lattice structure region １ , the theoretical depth of the recessed structure ΔH=H １ Step S100 of calculating *(1-L / P); Step S200: determining the allowable depth Δh of the sub-plate based on the material and thickness of the sub-plate; Step S300: comparing the allowable depth Δh of the sub-plate with the theoretical depth ΔH of the sinking structure; If Δh≧ΔH, do not install a recessed structure at a position adjacent to the lattice structure region in the non-lattice structure region, or etch the position adjacent to the lattice structure region in the non-lattice structure region to form a single annular groove, where the groove depth of the annular groove is equal to the theoretical depth of the recessed structure; If Δh<ΔH, step S500: installing a sinking structure in the non-lattice structure region at a position adjacent to the lattice structure region; A method for producing a nanoimprint master, comprising:

13. Step S500 sub-step S510, rounding up ΔH / Δh to obtain the number N of annular grooves of the sinking structure, where N is a positive integer greater than 1; a sub-step S520 of etching a portion of the non-lattice structure region adjacent to the lattice structure region to form N annular grooves that are connected to each other, wherein the groove depths of the N annular grooves decrease sequentially from the inside to the outside, and the difference in groove depth between two adjacent annular grooves is equal to the allowable depth of the sub-plate; The method for producing a nanoimprint master according to claim 12, comprising:

14. Step S500 a sub-step S510' of adjusting the material of the sub-plate and the thickness of the sub-plate to improve the allowable depth of the sub-plate, thereby obtaining an allowable improved depth Δh' of the sub-plate; If Δh′≧ΔH, then either the recessed structure is not provided in the non-lattice structure region at a position adjacent to the lattice structure region, or the non-lattice structure region at a position adjacent to the lattice structure region is etched to form a single annular groove, wherein the groove depth of the annular groove is equal to the theoretical depth of the recessed structure; and if Δh′<ΔH, round up ΔH / Δh′ to obtain the number N of annular grooves of the sunken structure, where N is a positive integer greater than 1; a sub-step S540′ of etching a portion of the non-lattice structure region adjacent to the lattice structure region to form N annular grooves that are connected to each other, wherein the groove depths of the N annular grooves decrease sequentially from the inside to the outside, and the difference in groove depth between two adjacent annular grooves is equal to the allowable depth of the sub-plate; The method for producing a nanoimprint master according to claim 12, comprising:

15. a step of manufacturing a nanoimprint master by the method for manufacturing a nanoimprint master according to any one of claims 12 to 14; imprinting a sub-plate substrate using the nanoimprint master and curing the substrate to form a nanoimprint sub-plate; using the nanoimprint subplate to imprint a waveguide substrate, and then hardening the substrate to form an optical waveguide; A method for manufacturing an optical waveguide, comprising:

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