Method for manufacturing grating structure and optical waveguide, display device

Abstract

The application relates to a manufacturing method of a grating structure, an optical waveguide and a display device. The manufacturing method comprises the following steps: providing a first to-be-processed substrate, the first to-be-processed substrate comprising a grating structure arranged in a first region, a second region and a third region; forming a first insulating layer in the first region and the second region; the thickness of the first insulating layer in the second region is gradually reduced in a stepped manner; forming a second insulating layer on the side of the first insulating layer away from the first to-be-processed substrate; forming a photoresist layer on the side of the second insulating layer away from the first to-be-processed substrate; etching the photoresist layer, the second insulating layer, the first insulating layer and the first surface of the first to-be-processed substrate to obtain a first processed substrate; wherein the grating structure comprises a first sub-grating structure located in the first region, a second sub-grating structure located in the second region and a third sub-grating structure located in the third region; the depth of the recess of the second sub-grating structure gradually increases. The application can improve the optical performance.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a method for manufacturing a grating structure, an optical waveguide, and a display device. Background Technology

[0002] With the development of augmented reality technology, AR headsets, AR glasses, and automotive HUDs (head-up displays) are gradually being recognized as next-generation computing and display platforms, and more and more manufacturers are investing heavily in research and development. The key optical components of these display devices are the optical engine that generates the image and the light transmission module that transmits the image to the eyes. The light transmission module is the most critical part, directly affecting the size, image quality, and viewing comfort of these display devices. Currently, the mainstream light transmission module in the industry is represented by optical waveguide devices.

[0003] However, existing technologies suffer from insufficient light transmission performance and manufacturing difficulties in grating sections at different depths on optical waveguides. Summary of the Invention

[0004] Therefore, it is necessary to address the problems of insufficient light transmission performance and manufacturing difficulties in grating sections with different depths on optical waveguides in the existing technology, and to provide a method for manufacturing grating structures, as well as optical waveguides and display devices.

[0005] According to a first aspect of this application, a method for manufacturing a grating structure is provided, comprising:

[0006] A first substrate to be processed is provided. The first substrate to be processed includes a first surface, and the first surface includes a first region, a second region, and a third region disposed sequentially. The first substrate to be processed includes a grating structure disposed in the first region, the second region, and the third region. The grating structure includes a plurality of protrusions and a plurality of recesses. The protrusions and the recesses are alternately disposed in the direction from the first region to the third region.

[0007] A first insulating layer is formed in the first region and the second region; the thickness of the first insulating layer is the same at all locations in the first region; the thickness of the first insulating layer in the second region is a step shape with a gradually decreasing thickness, and the first insulating layer in the second region includes a first end near the first region and a second end near the third region, the thickness of the first end being greater than the thickness of the second end;

[0008] A second insulating layer is formed on the side of the first insulating layer away from the first substrate to be processed, and the second insulating layer covers the first insulating layer;

[0009] A photoresist layer is formed on the side of the second insulating layer away from the first substrate to be processed, and the photoresist layer covers the second insulating layer;

[0010] The photoresist layer, the second insulating layer, the first insulating layer, and the first surface of the first substrate to be processed are etched to obtain a first processed substrate; wherein, in the first processed substrate, the grating structure includes a first sub-grating structure located in the first region, a second sub-grating structure located in the second region, and a third sub-grating structure located in the third region; in the direction from the first region to the third region, the depth of the recess of the second sub-grating structure gradually increases.

[0011] In some embodiments, in the first substrate to be processed, the depth of the recess in the first region, the depth of the recess in the second region, and the depth of the recess in the third region are the same;

[0012] In the first processed substrate, the depth of the recess in the first region is less than or equal to the depth of the recess in the second region, and the depth of the recess in the second region is less than or equal to the depth of the recess in the third region.

[0013] In some embodiments, in the first processed substrate, the depth of each of the recesses in the first region is the same; the depth of each of the recesses in the third region is the same.

[0014] In some embodiments, the step of forming a first insulating layer in the first region and the second region includes:

[0015] Provide the first mask template;

[0016] The first mask is disposed on one side of the first surface;

[0017] The first insulating layer is formed in the first region and the second region by a vapor deposition process, and the first mask is moved so that the thickness of the first insulating layer in the second region is in a step shape with a gradually decreasing thickness, and the thickness of the first end is greater than the thickness of the second end.

[0018] In some embodiments, the step of forming a first insulating layer in the first region and the second region includes:

[0019] Provide multiple second mask templates of different widths;

[0020] The second mask template is disposed on one side of the first surface;

[0021] The first insulating layer is formed in the first region and the second region by a vapor deposition process. By setting the second mask with different widths, the thickness of the first insulating layer in the second region is gradually reduced in a step shape, and the thickness of the first end is greater than the thickness of the second end.

[0022] In some embodiments, the material of the first insulating layer includes silicon nitride, and the material of the second insulating layer includes silicon oxide.

[0023] In some embodiments, the step of etching the photoresist layer, the second insulating layer, the first insulating layer, and the first surface of the first substrate to be processed includes:

[0024] The photoresist layer, the second insulating layer, the first insulating layer, and the first surface of the first substrate to be processed are etched using CF4 and O2 gases.

[0025] In some embodiments, the step of etching the photoresist layer, the second insulating layer, the first insulating layer, and the first surface of the first substrate to be processed includes: etching the recess in the second region and the recess in the third region.

[0026] According to a second aspect of this application, based on the same concept, an optical waveguide is provided, which is manufactured using the manufacturing method of the grating structure described in any one of the above claims.

[0027] According to a third aspect of this application, based on the same concept, a display device is provided, the display device including the optical waveguide.

[0028] In this embodiment, firstly, a first substrate to be processed is provided. The first substrate includes a first surface, which includes a first region, a second region, and a third region sequentially disposed thereon. The first substrate includes a grating structure disposed in the first region, the second region, and the third region. The grating structure includes multiple protrusions and multiple recesses, which are alternately disposed in the direction from the first region to the third region. Next, a first insulating layer is formed in the first region and the second region. The thickness of the first insulating layer is the same at all locations in the first region. The thickness of the first insulating layer in the second region is a step shape with gradually decreasing thickness. The first insulating layer includes a first end near the first region and a second end near the third region. The thickness of the first end is... The thickness of the first insulating layer is greater than that of the second end; then, a second insulating layer is formed on the side of the first insulating layer away from the first substrate to be processed, and the second insulating layer covers the first insulating layer; then, a photoresist layer is formed on the side of the second insulating layer away from the first substrate to be processed, and the photoresist layer covers the second insulating layer; finally, the photoresist layer, the second insulating layer, the first insulating layer, and the first surface of the first substrate to be processed are etched to obtain a first processed substrate; wherein, in the first processed substrate, the grating structure includes a first sub-grating structure located in a first region, a second sub-grating structure located in a second region, and a third sub-grating structure located in a third region; in the direction from the first region to the third region, the depth of the recess of the second sub-grating structure gradually increases. In one aspect, the thickness of the first insulating layer is the same at each location in the first region; after the etching process, the depth of each recess in the first region in the first processed substrate is the same. In another aspect, a first insulating layer is formed in the first region and the second region; no first insulating layer is formed in the third region; after the etching process, the depth of each recess in the third region in the first processed substrate is the same, and the depth of the recess in the second region is less than or equal to the depth of the recess in the third region. Thirdly, the thickness of the first insulating layer is the same at all locations in the first region; the thickness of the first insulating layer in the second region is a step shape with a gradually decreasing thickness, and the first insulating layer includes a first end near the first region and a second end near the third region, with the thickness of the first end being greater than that of the second end; after the etching process, the depth of the recess in the second region of the substrate after the first treatment gradually changes, and the depth of the recess in the second sub-grating structure gradually increases.Combining the first, second, and third aspects mentioned above, multiple depressions of different depths and / or multiple protrusions of different heights are formed in the first, second, and third regions, forming a sub-grating structure with a gradient structure. This simplifies the manufacturing process of the grating structure with the gradient portion, and the sub-grating structure with the gradient portion transitions smoothly with other parts of the grating structure. This eliminates the difference (difference / step difference) in the depth of the depression / height of the protrusion between two adjacent grating portions and / or different grating portions (sub-grating structures). This ensures that the transmission performance of light is sufficient / unchanged when propagating between adjacent and / or different grating portions (sub-grating structures), eliminating or avoiding the absence of grating effect in grating-free areas, and eliminating or avoiding the difference in light propagation at different grating portions. At the same time, the above-mentioned waveguide manufacturing method has the effect of simple process, and a grating structure with a gradient portion can be formed without multiple etching steps. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments or exemplary embodiments of this application, the drawings used in the description of the embodiments or exemplary embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the cross-sectional structure of an optical waveguide for related technologies.

[0031] Figure 2 This is a schematic diagram illustrating the process steps of a method for manufacturing a grating structure according to an embodiment of this application.

[0032] Figure 3 This is a schematic diagram of the first intermediate process of a method for manufacturing a grating structure according to an embodiment of this application.

[0033] Figure 4 This is a schematic diagram of the second intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application.

[0034] Figure 5 This is a schematic diagram of the third intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application.

[0035] Figure 6 This is a schematic diagram of the fourth intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application.

[0036] Figure 7 This is a schematic diagram of the fifth intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application.

[0037] Figure 8 This is a schematic diagram of the sixth intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application.

[0038] Figure 9 This is a schematic diagram of the seventh intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application.

[0039] Figure 10 This is a schematic diagram of the eighth intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application.

[0040] Figure 11 This is a schematic diagram of the ninth intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application.

[0041] Figure 12 This is a partially enlarged schematic diagram of a grating structure provided in an embodiment of this application.

[0042] Figure 13 This is a schematic diagram comparing the verification results of an optical waveguide provided in this application embodiment with those of the prior art.

[0043] Reference numerals: Optical waveguide 1000; First substrate to be processed 100; First surface 10a; Second surface 10b; First region 101; Second region 102; Third region 103; Grating structure 10W; Protrusion W1; Recess W2; First insulating layer 20; First end 21; Second end 22; Second insulating layer 30; Photoresist layer 40; First processed substrate 200; First sub-grating structure 10W1; Second sub-grating structure 10W2; Third sub-grating structure 10W3; First insulating raw material 20Y; First direction X; Second direction Y; First depth d1; First mask 70; Second mask 80; First dashed coil XQ1; Second dashed coil XQ2. Detailed Implementation

[0044] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0045] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0046] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0047] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0048] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0049] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0050] In existing technologies, there are problems such as insufficient light transmission performance and manufacturing difficulties in grating regions with different depths on optical waveguides. Please refer to... Figure 1 , Figure 1 This is a schematic diagram of the cross-sectional structure of an optical waveguide, based on related technologies. Figure 1 In the optical waveguide, a grating structure 10W is included. The grating structure 10W comprises a first sub-grating structure 10W1, a second sub-grating structure 10W2, and a third sub-grating structure 10W3 arranged sequentially adjacent to each other. The first sub-grating structure 10W1, the second sub-grating structure 10W2, and the third sub-grating structure 10W3 include multiple recesses of different depths and / or multiple protrusions of different heights. Different grating structures need to be formed through multiple step-by-step etching processes. However, the alignment accuracy of multiple step-by-step etching is difficult to control, and it is impossible to form a grating structure with gradually varying recess depths, such as... Figure 1 As shown by the two first dashed circles XQ1, there is a grating-free region between two adjacent grating parts (with obvious boundary gaps), and there is a significant difference (difference / step difference) in the depth of the depression or the height of the protrusion between two adjacent grating parts. This results in insufficient transmission performance when light propagates between two adjacent grating parts. The insufficient transmission performance includes the absence of grating effect in the grating-free region and a significant difference in light propagation compared to the propagation in the grating parts on both sides. At the same time, it is difficult to manufacture high-precision optical waveguides (e.g., without boundary gaps) for different grating parts.

[0051] To address the aforementioned issues, this application provides a method for manufacturing a grating structure, as well as an optical waveguide and a display device.

[0052] Please see Figures 2 to 13 . Figure 2 This is a schematic diagram illustrating the process steps of a method for manufacturing a grating structure according to an embodiment of this application. Figure 3 This is a schematic diagram of the first intermediate process of a method for manufacturing a grating structure according to an embodiment of this application. Figure 4 This is a schematic diagram of the second intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application. Figure 5 This is a schematic diagram of the third intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application. Figure 6This is a schematic diagram of the fourth intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application. Figure 7 This is a schematic diagram of the fifth intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application. Figure 8 This is a schematic diagram of the sixth intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application. Figure 9 This is a schematic diagram of the seventh intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application. Figure 10 This is a schematic diagram of the eighth intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application. Figure 11 This is a schematic diagram of the ninth intermediate process of a method for manufacturing a grating structure provided in an embodiment of this application. Figure 12 This is a partially enlarged schematic diagram of a grating structure provided in an embodiment of this application. Figure 13 This is a schematic diagram comparing the verification results of an optical waveguide provided in this application embodiment with those of the prior art.

[0053] Firstly, such as Figure 2 As shown, this application provides a method for manufacturing a grating structure, which includes steps S100, S200, S300, S400, and S500.

[0054] Step S100: A first substrate to be processed is provided. The first substrate to be processed includes a first surface, and the first surface includes a first region, a second region, and a third region disposed sequentially. The first substrate to be processed includes a grating structure disposed in the first region, the second region, and the third region. The grating structure includes a plurality of protrusions and a plurality of recesses, and the protrusions and the recesses are alternately disposed in the direction from the first region to the third region.

[0055] For example, step S100, as follows Figure 3 As shown, a first substrate to be processed 100 is provided. The first substrate to be processed 100 includes a first surface 10a, and the first surface 10a includes a first region 101, a second region 102 and a third region 103 arranged sequentially. The first substrate to be processed 100 includes a grating structure 10W disposed in the first region 101, the second region 102 and the third region 103. The grating structure 10W includes a plurality of protrusions W1 and a plurality of recesses W2. The protrusions W1 and the recesses W2 are alternately arranged in the direction from the first region 101 to the third region 103.

[0056] For example, the direction from the first region 101 to the third region 103 is the first direction X, which is perpendicular to the thickness direction of the first substrate 100 to be processed.

[0057] For example, the thickness direction of the first substrate to be processed 100 / the thickness direction of the first processed substrate 200 is the second direction Y.

[0058] For example, the first substrate to be processed 100 is a substrate or waveguide substrate that has obtained the grating structure 10W through a single etching process. On the first substrate to be processed 100, each protrusion W1 has the same height in the second direction Y, and each recess W2 has the same depth in the second direction Y.

[0059] For example, the first substrate to be processed 100 includes a first surface 10a and a second surface 10b disposed opposite to each other.

[0060] Step S200: A first insulating layer is formed in the first region and the second region; the thickness of the first insulating layer is the same at all locations in the first region; the thickness of the first insulating layer in the second region is a step shape with gradually decreasing thickness, and the first insulating layer in the second region includes a first end near the first region and a second end near the third region, the thickness of the first end being greater than the thickness of the second end.

[0061] For example, such as Figures 4 to 6 As shown, a first insulating layer 20 is formed in a first region 101 and a second region 102; the thickness of the first insulating layer 20 is the same at all locations in the first region 101; the thickness of the first insulating layer 20 in the second region 102 is a step shape with gradually decreasing thickness; the first insulating layer 20 in the second region 102 includes a first end 21 near the first region 101 and a second end 22 near the third region 103, and the thickness of the first end 21 is greater than the thickness of the second end 22.

[0062] For example, the thickness of the first insulating layer 20 is the same at all locations in the first region 101; so that in the subsequent step S500, the depth of each recess W2 in the first region 101 in the first processed substrate 200 is the same.

[0063] For example, a first insulating layer 20 is formed in the first region 101 and the second region 102; no first insulating layer 20 is formed in the third region 103; so that in the subsequent step S500, the depth of each recess W2 in the third region 103 in the first processed substrate 200 is the same, and the depth of the recess W2 in the second region 102 is less than or equal to the depth of the recess W2 in the third region 103.

[0064] For example, the thickness of the first insulating layer 20 is the same at all locations in the first region 101; the thickness of the first insulating layer 20 in the second region 102 is a step shape with a gradually decreasing thickness. The first insulating layer 20 includes a first end 21 near the first region 101 and a second end 22 near the third region 103. The thickness of the first end 21 is greater than the thickness of the second end 22. This is so that in the subsequent step S500, the depth of the recess W2 in the second region 102 in the first processed substrate 200 gradually changes and the depth of the recess W2 in the second sub-grating structure 10W2 gradually increases.

[0065] In step S300, a second insulating layer is formed on the side of the first insulating layer away from the first substrate to be processed, and the second insulating layer covers the first insulating layer.

[0066] For example, such as Figure 7 As shown, a second insulating layer 30 is formed on the side of the first insulating layer 20 away from the first substrate 100 to be processed, and the second insulating layer 30 covers the first insulating layer 20.

[0067] For example, the second insulating layer 30 is made of a different material than the first insulating layer 20. For instance, the second insulating layer 30 is made of either silicon nitride or silicon oxide, while the first insulating layer 20 is made of either silicon nitride or silicon oxide.

[0068] For example, a second insulating layer 30 of silicon nitride material can be used by plasma-enhanced chemical vapor deposition (PECVD) to form an effective thickness gradient by non-ideal coverage of the multilayer structure boundary of the first insulating layer 20.

[0069] Step S400: A photoresist layer is formed on the side of the second insulating layer away from the first substrate to be processed, and the photoresist layer covers the second insulating layer.

[0070] For example, such as Figure 8 As shown, a photoresist layer 40 is formed on the side of the second insulating layer 30 away from the first substrate 100 to be processed, and the photoresist layer 40 covers the second insulating layer 30.

[0071] For example, the photoresist layer 40 serves to precisely define the positions of the first region 101, the second region 102, and the third region 103 through an exposure process. This allows for subsequent etching at different depths in the three regions by defining their positions.

[0072] For example, in the first region 101, the first insulating layer 20, the second insulating layer 30, and the photoresist layer 40 are sequentially stacked. In the second region 102, the first insulating layer 20, the second insulating layer 30, and the photoresist layer 40 are sequentially stacked. In the third region 103, the second insulating layer 30 and the photoresist layer 40 are sequentially stacked.

[0073] Step S500: Etch the photoresist layer, the second insulating layer, the first insulating layer, and the first surface of the first substrate to be processed to obtain a first processed substrate; wherein, in the first processed substrate, the grating structure includes a first sub-grating structure located in the first region, a second sub-grating structure located in the second region, and a third sub-grating structure located in the third region; in the direction from the first region to the third region, the depth of the recess of the second sub-grating structure gradually increases.

[0074] For example, such as Figures 9 to 11 As shown, the photoresist layer 40, the second insulating layer 30, the first insulating layer 20, and the first surface 10a of the first substrate to be processed 100 are etched to obtain the first processed substrate 200; wherein, in the first processed substrate 200, the grating structure 10W includes a first sub-grating structure 10W1 located in the first region 101, a second sub-grating structure 10W2 located in the second region 102, and a third sub-grating structure 10W3 located in the third region 103; in the direction from the first region 101 to the third region 103, the depth of the recess W2 of the second sub-grating structure 10W2 gradually increases.

[0075] For example, such as Figures 9 to 11 As shown, the photoresist layer 40, the second insulating layer 30, the first insulating layer 20 and the first surface 10a of the first substrate to be processed 100 are etched using the same etching process to obtain the first processed substrate 200.

[0076] For example, such as Figure 9 and Figure 10 As shown, in step S500, the photoresist layer 40 and the second insulating layer 30 are etched first; then the third region 103 and the first insulating layer 20 are etched, and after a portion of the first insulating layer 20 is etched, regions 9 and 103 are formed. Figure 10 The slope shown Figure 10 The second dashed coil XQ2 shown illustrates a ramp shape; then the third region 103 is etched, the second region 102 and the first region 101 are etched; finally, the first sub-grating structure 10W1 located in the first region 101, the second sub-grating structure 10W2 located in the second region 102 and the third sub-grating structure 10W3 located in the third region 103 are formed.

[0077] For example, in the etching process of step S500, the photoresist layer 40 and the second insulating layer 30 of equal thickness are penetrated first, and the third region 103, which does not have the first insulating layer 20, is etched first. Then, the slope shape of the first insulating layer 20 is preserved by utilizing the selectivity ratio of the second insulating layer 30 / first insulating layer 20 (e.g., silicon oxide / silicon nitride), and the slope shape is lengthened by CF4 / O2 etching gas. Then, when the etching gas penetrates the slope shape, the area of ​​the first surface 10a shielded by the first insulating layer 20 is etched later, and the area of ​​the first surface 10a not shielded by the first insulating layer 20 is etched earlier, converting the thickness of the slope shape of the first insulating layer 20 into the time for the first surface 10a or the recess W2 to be penetrated / etched. Finally, after the first insulating layer 20 is asynchronously / gradually penetrated / etched, the substrate of the first surface 10a is fully exposed. All the previous time differences are converted into the depth difference of the first surface 10a or the recess W2.

[0078] In this embodiment, firstly, a first substrate to be processed is provided. The first substrate includes a first surface, which includes a first region, a second region, and a third region sequentially disposed thereon. The first substrate includes a grating structure disposed in the first region, the second region, and the third region. The grating structure includes multiple protrusions and multiple recesses, which are alternately disposed in the direction from the first region to the third region. Next, a first insulating layer is formed in the first region and the second region. The thickness of the first insulating layer is the same at all locations in the first region. The thickness of the first insulating layer in the second region is a step shape with gradually decreasing thickness. The first insulating layer includes a first end near the first region and a second end near the third region. The thickness is greater than the thickness of the second end; then, a second insulating layer is formed on the side of the first insulating layer away from the first substrate to be processed, and the second insulating layer covers the first insulating layer; then, a photoresist layer is formed on the side of the second insulating layer away from the first substrate to be processed, and the photoresist layer covers the second insulating layer; finally, the photoresist layer, the second insulating layer, the first insulating layer, and the first surface of the first substrate to be processed are etched to obtain a first processed substrate; wherein, in the first processed substrate, the grating structure includes a first sub-grating structure located in a first region, a second sub-grating structure located in a second region, and a third sub-grating structure located in a third region; in the direction from the first region to the third region, the depth of the recess of the second sub-grating structure gradually increases. In a first aspect, the thickness of the first insulating layer 20 is the same at each location in the first region 101; after the etching process, the depth of each recess W2 in the first region 101 in the first processed substrate 200 is the same. Secondly, a first insulating layer 20 is formed in the first region 101 and the second region 102; no first insulating layer 20 is formed in the third region 103; after the etching process, the depth of each recess W2 in the third region 103 in the first processed substrate 200 is the same, and the depth of the recess W2 in the second region 102 is less than or equal to the depth of the recess W2 in the third region 103. Thirdly, the thickness of the first insulating layer 20 is the same at each location in the first region 101; the thickness of the first insulating layer 20 in the second region 102 is a step shape with a gradually decreasing thickness, the first insulating layer 20 includes a first end 21 near the first region 101 and a second end 22 near the third region 103, the thickness of the first end 21 is greater than the thickness of the second end 22; after the etching process, the depth of the recess W2 in the second region 102 in the first processed substrate 200 gradually changes, and the depth of the recess W2 in the second sub-grating structure 10W2 gradually increases.Combining the first, second, and third aspects mentioned above, multiple recesses W2 of different depths and / or multiple protrusions W1 of different heights are formed in the first region 101, the second region 102, and the third region 103, forming a sub-grating structure with a gradient structure. This simplifies the manufacturing process of the grating structure with the gradient portion, and the sub-grating structure with the gradient portion transitions smoothly with other parts of the grating structure. This eliminates the difference (difference / step difference) in the depth of the recess / height of the protrusion between two adjacent grating portions and / or different grating portions (sub-grating structures). This ensures that the transmission performance of light is sufficient / unchanged when propagating between adjacent and / or different grating portions (sub-grating structures), eliminating or avoiding the absence of grating effect in grating-free areas, and eliminating or avoiding the difference in light propagation at different grating portions. At the same time, the manufacturing method of the optical waveguide 1000 has the effect of simple process, and a grating structure with a gradient portion can be formed without multiple etching steps.

[0079] In some implementations, such as Figure 3 As shown, in the first substrate to be processed 100, the depth of the recess W2 in the first region 101, the depth of the recess W2 in the second region 102, and the depth of the recess W2 in the third region 103 are the same. Figure 11 and Figure 12 As shown, in the first processed substrate 200, the depth of the recess W2 in the first region 101 is less than or equal to the depth of the recess W2 in the second region 102, and the depth of the recess W2 in the second region 102 is less than or equal to the depth of the recess W2 in the third region 103.

[0080] For example, such as Figure 3 As shown, in the first substrate to be processed 100, the depth of the recess W2 in the first region 101, the depth of the recess W2 in the second region 102, and the depth of the recess W2 in the third region 103 are the same; in the first substrate to be processed 100, the depth of the recess W2 in the first sub-grating structure 10W1, the depth of the recess W2 in the second sub-grating structure 10W2, and the depth of the recess W2 in the third sub-grating structure 10W3 are the same.

[0081] For example, such as Figure 11 and Figure 12 As shown, in the first processed substrate 200, the depth of the recess W2 in the first region 101 is less than or equal to the minimum depth of the recess W2 in the second region 102, and the maximum depth of the recess W2 in the second region 102 is less than or equal to the depth of the recess W2 in the third region 103; in the first processed substrate 200, the depth of the recess W2 in the first sub-grating structure 10W1 is less than or equal to the minimum depth of the recess W2 in the second sub-grating structure 10W2, and the maximum depth of the recess W2 in the second sub-grating structure 10W2 is less than or equal to the depth of the recess W2 in the third sub-grating structure 10W3.

[0082] For example, such as Figure 11 and Figure 12 As shown, the second region 102 is a gradient sub-grating structure / sub-grating part, and the first sub-grating structure 10W1, the second sub-grating structure 10W2 and the third sub-grating structure 10W3 together form an overall gradient grating structure.

[0083] For example, such as Figure 12 As shown, it is easy to understand that the depth of the depression W2 refers to the depth of the depression W2 in the second direction Y. Figure 12 The depth of the depression W2 is shown as the first depth d1.

[0084] In some implementations, such as Figure 11 and Figure 12 As shown, in the first processed substrate 200, the depth of each recess W2 in the first region 101 is the same; the depth of each recess W2 in the third region 103 is the same.

[0085] For example, such as Figure 11 and Figure 12 As shown, in the first processed substrate 200, the depth of each recess W2 of the first sub-grating structure 10W1 is the same; the depth of each recess W2 of the third sub-grating structure 10W3 is the same; in the first processed substrate 200, the depth of each recess W2 of the first sub-grating structure 10W1 is the same; the depth of each recess W2 of the third sub-grating structure 10W3 is the same.

[0086] In some implementations, such as Figures 4 to 6 As shown, the step of forming the first insulating layer 20 in the first region 101 and the second region 102 (step S200) includes: step S201, providing a first mask 70; step S202, setting the first mask 70 on one side of the first surface 10a; step S203, forming the first insulating layer 20 in the first region 101 and the second region 102 by a vapor deposition process, and moving the first mask 70 so that the thickness of the first insulating layer 20 in the second region 102 is in a step shape with a gradually decreasing thickness, and the thickness of the first end 21 is greater than the thickness of the second end 22.

[0087] For example, such as Figures 4 to 6As shown, in some embodiments, when the first insulating layer 20 is formed in the first region 101 and the second region 102 during the vapor deposition process, the first mask 70 can be moved so that the edge of the orthographic projection of the first mask 70 on the first surface 10a gradually moves closer to the first region 101 in the second region 102, thereby forming different shielding states on the raw material (first insulating raw material 20Y) of the vapor deposition process. This results in the thickness of the first insulating layer 20 in the second region 102 being a step shape with gradually decreasing thickness, and the thickness of the first end 21 being greater than the thickness of the second end 22.

[0088] In some implementations, such as Figures 4 to 6 As shown, the step of forming the first insulating layer 20 in the first region 101 and the second region 102 (step S200) includes: step S2001, providing a plurality of second mask templates 80 with different widths; step S2002, setting the second mask templates 80 on one side of the first surface 10a; step S2003, forming the first insulating layer 20 in the first region 101 and the second region 102 by a vapor deposition process, and by setting the second mask templates 80 with different widths, the thickness of the first insulating layer 20 in the second region 102 is gradually decreasing in a step shape, and the thickness of the first end 21 is greater than the thickness of the second end 22.

[0089] For example, such as Figures 4 to 6 As shown, in some other embodiments, when the first insulating layer 20 is formed in the first region 101 and the second region 102, second mask templates 80 of different widths can be provided so that the edge of the orthographic projection of the second mask template 80 on the first surface 10a gradually approaches the first region 101 in the second region 102, thereby forming different shielding states on the raw material (first insulating raw material 20Y) of the vapor deposition process, so that the thickness of the first insulating layer 20 in the second region 102 is in a step shape with a gradual decrease, and the thickness of the first end 21 is greater than the thickness of the second end 22.

[0090] In some embodiments, the material of the first insulating layer 20 includes silicon nitride, and the material of the second insulating layer 30 includes silicon oxide.

[0091] In some embodiments, the step of etching the photoresist layer 40, the second insulating layer 30, the first insulating layer 20 and the first surface 10a of the first substrate to be processed 100 (step S500) includes: etching the photoresist layer 40, the second insulating layer 30, the first insulating layer 20 and the first surface 10a of the first substrate to be processed 100 by CF4 and O2 gas (tetrafluoromethane and oxygen).

[0092] For example, CF4 provides fluorine radicals to etch the second insulating layer 30, while the addition of O2 can accelerate the removal / etching of the photoresist layer 40 and the polymer, and adjust the lateral (in the direction parallel to the first surface 10a) erosion rate of the chemical reaction.

[0093] In some implementations, such as Figure 10 and Figure 11 As shown, the step of etching the photoresist layer 40, the second insulating layer 30, the first insulating layer 20 and the first surface 10a of the first substrate to be processed 100 (step S500) includes: etching the recess W2 of the second region 102 and the recess W2 of the third region 103.

[0094] For example, in step S500, the recess W2 of the third region 103 is first etched, and then the recess W2 of the second region 102 and the recess W2 of the third region 103 are etched simultaneously; so that in the first processed substrate 200, the depth of the recess W2 of the first region 101 is less than or equal to the depth of the recess W2 of the second region 102, and the depth of the recess W2 of the second region 102 is less than or equal to the depth of the recess W2 of the third region 103; so that the depth of the recess W2 of the second region 102 in the first processed substrate 200 gradually changes, and the depth of the recess W2 of the second sub-grating structure 10W2 gradually increases.

[0095] It should be noted that, according to the inventor's verification, it is possible to create a region with a length greater than 10mm in the first direction X and a depth of 10nm-100nm for the recessed W2.

[0096] It should be noted that, as Figure 13 As shown, the verification results of Samples 1, 2, and 3 of the embodiments of this application are compared with those of Comparative Example 1 of the prior art. The widths of the second region 102 in the first direction X of Samples 1, 2, and 3 are 2 mm, 5 mm, and 10 mm, respectively. The difference between the maximum and minimum depths of the depression W2 in the second region 102 of Samples 1, 2, and 3 is 10 nm. The light extraction efficiencies of Samples 1, 2, and 3 are 109.5 nit / lm, 110.2 nit / lm, and 108.5 nit / lm, respectively. The 9-point brightness uniformity of Samples 1, 2, and 3 are 57.1%, 59%, and 63.2%, respectively. Comparative Example 1 was manufactured using a prior art multiple etching process (e.g., ...). Figure 1 As shown), the difference between the maximum and minimum depths of the depression in Comparative Example 1 is 10 nm. The light extraction efficiency of Comparative Example 1 is 106.8 nit / lm, and the 9-point brightness uniformity of Comparative Example 1 is 57.2%. From... Figure 13 As can be seen, the embodiments of this application (such as sample 3) can effectively improve brightness uniformity and achieve excellent optical effects.

[0097] Secondly, based on the same application concept, such as Figure 11 As shown, this application also provides an optical waveguide 1000, which is manufactured using the manufacturing method of the grating structure described above.

[0098] Thirdly, based on the same concept, this application also provides a display device, which includes the optical waveguide 1000 of any one of the above.

[0099] For example, the display device includes a display module and an optical waveguide 1000. The display module is used to emit image light; the optical waveguide 1000 is used to receive image light. The optical waveguide in the display device can be any of the optical waveguide 1000 in the above embodiments, and the optical waveguide 1000 in the display device can have any one or any combination of the features in the above embodiments.

[0100] For example, the display module (i.e., the image source) can be a microdisplay, which provides display content to the device. The microdisplay can be a self-emissive active device, such as a micro-OLED (µOLED) or micro-LED (µLED), or it can be a liquid crystal display (including transmissive Liquid Crystal Display (LCD) and reflective Liquid Crystal on Silicon (LCOS), as well as digital micromirror arrays (DMD, the core of Digital Light Processing (DLP)) and linear beam scanners (LBS) that require external illumination. The type of image source is not limited to these. Optical components can transmit and / or modulate the image light.

[0101] For example, the display device can be augmented reality (AR) glasses, in-vehicle HUD displays, aerial holographic displays, etc., but is not limited to these.

[0102] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0103] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions 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 various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for manufacturing a grating structure, characterized in that, include: A first substrate to be processed is provided. The first substrate to be processed includes a first surface, and the first surface includes a first region, a second region, and a third region disposed sequentially. The first substrate to be processed includes a grating structure disposed in the first region, the second region, and the third region. The grating structure includes a plurality of protrusions and a plurality of recesses. The protrusions and the recesses are alternately disposed in the direction from the first region to the third region. A first insulating layer is formed in the first region and the second region; The thickness of the first insulating layer is the same at all locations in the first region; the thickness of the first insulating layer in the second region is a step shape with a gradually decreasing thickness, and the first insulating layer in the second region includes a first end near the first region and a second end near the third region, the thickness of the first end being greater than the thickness of the second end; A second insulating layer is formed on the side of the first insulating layer away from the first substrate to be processed, and the second insulating layer covers the first insulating layer; A photoresist layer is formed on the side of the second insulating layer away from the first substrate to be processed, and the photoresist layer covers the second insulating layer; The photoresist layer, the second insulating layer, the first insulating layer, and the first surface of the first substrate to be processed are etched to obtain a first processed substrate; wherein, in the first processed substrate, the grating structure includes a first sub-grating structure located in the first region, a second sub-grating structure located in the second region, and a third sub-grating structure located in the third region; in the direction from the first region to the third region, the depth of the recess of the second sub-grating structure gradually increases.

2. The method for manufacturing the grating structure according to claim 1, characterized in that, In the first substrate to be processed, the depth of the recess in the first region, the depth of the recess in the second region, and the depth of the recess in the third region are the same; In the first processed substrate, the depth of the recess in the first region is less than or equal to the depth of the recess in the second region, and the depth of the recess in the second region is less than or equal to the depth of the recess in the third region.

3. The method for manufacturing the grating structure according to claim 2, characterized in that, In the first processed substrate, the depth of each of the recesses in the first region is the same; the depth of each of the recesses in the third region is the same.

4. The method for manufacturing the grating structure according to claim 1, characterized in that, The step of forming a first insulating layer in the first region and the second region includes: Provide the first mask template; The first mask is disposed on one side of the first surface; The first insulating layer is formed in the first region and the second region by a vapor deposition process, and the first mask is moved so that the thickness of the first insulating layer in the second region is in a step shape with a gradually decreasing thickness, and the thickness of the first end is greater than the thickness of the second end.

5. The method for manufacturing the grating structure according to claim 1, characterized in that, The step of forming a first insulating layer in the first region and the second region includes: Provide multiple second mask templates of different widths; The second mask template is disposed on one side of the first surface; The first insulating layer is formed in the first region and the second region by a vapor deposition process. By setting the second mask with different widths, the thickness of the first insulating layer in the second region is gradually reduced in a step shape, and the thickness of the first end is greater than the thickness of the second end.

6. The method for manufacturing the grating structure according to claim 1, characterized in that, The first insulating layer is made of silicon nitride, and the second insulating layer is made of silicon oxide.

7. The method for manufacturing the grating structure according to claim 1, characterized in that, The step of etching the photoresist layer, the second insulating layer, the first insulating layer, and the first surface of the first substrate to be processed includes: The photoresist layer, the second insulating layer, the first insulating layer, and the first surface of the first substrate to be processed are etched using CF4 and O2 gases.

8. The method for manufacturing the grating structure according to claim 1, characterized in that, The step of etching the photoresist layer, the second insulating layer, the first insulating layer, and the first surface of the first substrate to be processed includes: etching the depression in the second region and the depression in the third region.

9. An optical waveguide, characterized in that, It is manufactured using the manufacturing method of the grating structure as described in any one of claims 1 to 8.

10. A display device, characterized in that, Including the optical waveguide as described in claim 9.

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