Grating preparation method, grating structure and optical waveguide
By filling material in the grating tooth gaps of the optical waveguide and etching to form a highly graded grating, the problem of poor brightness uniformity of the optical waveguide is solved and more stable and uniform optical performance is achieved.
Patent Information
- Application Number
- CN202411623203.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-14
- Publication Date
- 2025-01-21
AI Technical Summary
Existing optical waveguides lead to poor brightness uniformity during height modulation, and there is a problem of sudden brightness changes.
A filling layer is formed by filling the gaps between the grating teeth with material, and the grating teeth and the filling layer in the grating area are simultaneously etched downward at a preset etching selectivity ratio to form a grating with a bottom-aligned height gradient.
It significantly improves the uniformity of the brightness of the optical wave guide, and improves the stability of the grating through the supporting effect of the fill layer to avoid collapse.
Smart Images
Figure CN119335636A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure generally relates to the field of optical waveguide grating technology, and more specifically, to a grating preparation method, a grating structure, and an optical waveguide. Background Art
[0002] As an important component of AR display devices, optical waveguides are mainly used to transmit images or information from displays to the user's eyes. In order to meet the needs of AR display, optical waveguides are constantly improved to improve optical performance. Among them, parameter modulation has a particularly important impact on the performance of optical waveguides, and height modulation is a more prominent parameter among the many influencing factors in parameter modulation. By performing height modulation on different partitions of the optical waveguide, the performance of the optical waveguide can be significantly improved. At present, most practices of height modulation are to divide the coupling region, turning region, and coupling region of the optical waveguide into multiple sub-regions, and perform partition etching on the height of different sub-regions. However, this height modulation will cause a significant height difference in the grating height of different sub-regions. Although such a height difference can improve the optical performance to a certain extent, it will bring about problems such as brightness mutation, resulting in poor brightness uniformity of the optical waveguide.
[0003] In view of this, there is an urgent need to provide a grating preparation method, a grating structure and an optical waveguide, so as to improve the brightness uniformity of the optical waveguide. Summary of the invention
[0004] In order to at least solve one or more of the technical problems mentioned above, the present disclosure proposes a grating preparation method, a grating structure and an optical waveguide in the following aspects.
[0005] In the first aspect, an optical film layer is coated on the surface of a substrate, and the optical film layer is etched to form grating teeth; a material is filled into the gaps between the grating teeth to form a filling layer, wherein the filling material and the grating teeth are different materials; and the grating teeth and the filling layer in the grating area are synchronously etched downward at a preset etching selection ratio to form a bottom-aligned height-gradient grating.
[0006] In some embodiments, coating an optical film layer on the surface of a substrate and etching the optical film layer so that the optical film layer forms grating teeth includes: coating a layer of the optical film layer on the surface of the substrate; forming etching masks arranged at intervals on the surface of the optical film layer; and etching the optical film layer so that the optical film layer forms the grating teeth.
[0007] In some embodiments, the etching mask arranged at intervals on the surface of the optical film layer includes: coating photoresist water or nanoimprint glue on the surface of the optical film layer; and using photolithography technology or nanoimprint technology to form a photoresist pattern arranged at intervals on the surface of the optical film layer to serve as the etching mask.
[0008] In some embodiments, before filling the gaps between the grating teeth with a material to form a filling layer, the method further comprises: removing the etching mask on the surface of the optical film layer.
[0009] In some embodiments, filling the gaps between the grating teeth with material to form the filling layer comprises: filling the gaps between the grating teeth with material; and removing excess filling material exceeding the height of the grating teeth to form the filling layer.
[0010] In some embodiments, before synchronously etching the grating teeth and the filling layer in the grating region with a preset etching selectivity to form a bottom-aligned height gradient grating, the method further includes: forming a grating pattern on the surface of the grating teeth in the grating region of the substrate, and forming an etching mask on the surface of the non-grating region of the substrate, wherein the non-grating region is located around the grating region.
[0011] In some embodiments, after synchronously etching downward the grating teeth and the filling layer in the grating area with a preset etching selectivity to form a bottom-aligned height-gradient grating, the method further comprises: removing the etching mask in the non-grating area.
[0012] In some embodiments, after removing the etching mask on the surface of the non-grating area, the method further comprises: removing the optical film layer in the non-grating area.
[0013] In some embodiments, after synchronously etching the grating teeth and the filling layer in the grating area with a preset etching selectivity to form a bottom-aligned height-gradient grating, the method further includes: removing the filling layer to form a bottom-aligned height-gradient grating.
[0014] In some embodiments, the grating teeth are in the shape of straight teeth or helical teeth.
[0015] In some embodiments, the preset etching ratio is in the range of [0.8, 1.2].
[0016] In a second aspect, the present disclosure provides a grating structure, comprising: a substrate; a grating arranged on the substrate; and a filling layer arranged in the grating gap, wherein the filling layer and the grating are made of different materials, the heights of the grating and the filling layer show a gradual increase or decrease, and the bottoms of the grating and the filling layer are aligned.
[0017] In a third aspect, the present disclosure provides an optical waveguide, comprising a grating prepared by the grating preparation method of the first aspect and any embodiment thereof, or comprising the grating structure described in the second aspect.
[0018] Through a grating preparation method as provided above, the disclosed embodiment first fills the gap between the grating teeth with material to form a filling layer, and then simultaneously etches the grating teeth and the filling layer in the grating area downward with a preset etching selection ratio, thereby finally forming a bottom-aligned height gradient grating including the filling layer. Through such step operations, the disclosed solution can significantly improve the brightness uniformity of the optical waveguide including the grating. Furthermore, the filling layer also supports the grating, thereby improving the stability of the grating and making it less likely to collapse. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] By reading the detailed description below with reference to the accompanying drawings, the above and other purposes, features and advantages of the exemplary embodiments of the present disclosure will become readily understood. In the accompanying drawings, several embodiments of the present disclosure are illustrated in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:
[0020] Figure 1 is a flow chart of a grating preparation method according to some embodiments of the present disclosure;
[0021] Figure 2 is a flow chart of a grating preparation method according to some embodiments of the present disclosure;
[0022] Figure 3 is a flow chart of a grating preparation method according to some embodiments of the present disclosure;
[0023] Figure 4 is a flow chart of a grating preparation method according to some embodiments of the present disclosure;
[0024] Figure 5 is a schematic diagram of the structure of the grating structure of some embodiments of the present disclosure;
[0025] Figure 6 Yes Execution Figure 1 Schematic diagram of the grating structure obtained after the corresponding steps;
[0026] Figure 7 Yes Execution Figure 2 Schematic diagram of the grating structure obtained after the corresponding steps;
[0027] Figure 8 Yes Execution Figure 3 Schematic diagram of the grating structure obtained after the corresponding steps;
[0028] Fig. 9 Yes Execution Figure 4 Schematic diagram of the grating structure obtained after the corresponding steps in . DETAILED DESCRIPTION
[0029] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.
[0030] It should be understood that the terms "include" and "comprising" used in the specification and claims of the present disclosure indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.
[0031] It should also be understood that the terms used in this disclosure are only for the purpose of describing specific embodiments and are not intended to limit the disclosure. As used in this disclosure and claims, the singular forms of "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" used in this disclosure and claims refers to any combination of one or more of the associated listed items and all possible combinations, including these combinations.
[0032] As used in this specification and claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.
[0033] The specific implementation of the present disclosure is described in detail below with reference to the accompanying drawings.
[0034] See also Figure 1 and Figure 6 , Figure 1 is a flow chart of a grating preparation method 10 according to some embodiments of the present disclosure, Figure 6 Yes Execution Figure 1 Schematic diagram of the grating structure obtained after the corresponding steps in .
[0035] like Figure 1 and Figure 6As shown, at step S101, method 10 coats an optical film layer on the surface of the substrate and etches the optical film layer so that the optical film layer forms grating teeth. In the disclosed embodiment, since the grating teeth can be used for grating preparation, the optical film layer material can be selected from one or more materials such as TiO2, SiN, SiO2, amorphous silicon A-Si, Al2O3, etc. Further, the substrate can be selected from materials with good optical properties such as glass, Si, Al2O3, Si3N4, etc.
[0036] In some embodiments, the substrate and the optical film layer discussed above can be made of different materials or the same material. For example, the substrate can be made of SiO2 (glass) and the optical film layer can be made of TiO2. Alternatively, both the substrate and the optical film layer can be made of SiO2.
[0037] In some embodiments, the height and width of the grating teeth may be consistent. Or both the height and width of the grating teeth may be inconsistent. In other embodiments, the grating teeth may also be duty cycle modulated, and their width is affected by the duty cycle. In view of this, the scheme disclosed in the present invention does not specifically limit the height and width of the grating teeth, and those skilled in the art may select appropriate height and width based on the disclosure and teachings of the present invention. Further, in some embodiments, the shape of the grating teeth in the foregoing text may be straight teeth or helical teeth.
[0038] The process then proceeds to step S102. At step S102, the method 20 fills the gaps between the grating teeth with material to form a filling layer, wherein the filling layer and the grating teeth are made of different materials. In the disclosed embodiment, the filling layer can support the grating teeth so that the grating teeth are not easy to collapse, thereby significantly improving the stability of the grating teeth.
[0039] In some embodiments, the filling material may be one or more of TiO2, SiN, SiO2, A-Si, Al2O3 and the like. Furthermore, one or more of CVD (Chemical Vapor Deposition), ALD (Atomic Layer Deposition), and PVD (Physical Vapor Deposition) techniques may be used to fill the gaps between the grating teeth with the aforementioned filling material. In other embodiments, the filling material may also be a spin-coated organic material.
[0040] In some embodiments, the height of the filling layer is equal to the height of the grating teeth. Based on this, at step S102, after method 20 fills the gaps of the grating teeth with material, it can further remove excess filling material that exceeds the height of the grating teeth to form a filling layer with a height equal to the height of the grating teeth, and expose the surfaces of the grating teeth and the filling layer, so as to facilitate subsequent etching thereof while keeping the surface of the substrate flat. As an example, etching technology or chemical mechanical polishing process can be used to remove excess filling material that exceeds the height of the grating teeth. For example, wet etching technology can be used to remove excess filling material that exceeds the height of the grating teeth.
[0041] Finally, at step S103, the method 10 synchronously etches the grating teeth and the filling layer in the grating region downward with a preset etching selection ratio to form a bottom-aligned height gradient grating. In the disclosed embodiment, the grating teeth and the filling layer in the grating region are etched to finally form a bottom-aligned height gradient grating including the filling layer, while the non-grating region is not processed, so that the prepared grating is formed into a wedge-shaped structure with a concave middle and convex sides. Specifically, the concave part in the middle is the grating region, including the grating teeth and the filling layer, and the convex parts on both sides are the non-grating region.
[0042] In some other embodiments, the entire grating teeth and filling layer region on the substrate can be used as the grating region. In view of this, after the grating teeth and filling in the grating region are synchronously etched downward with a preset etching selection ratio, a grating with a bottom-aligned height gradient and a trapezoidal structure including a filling layer can be directly formed.
[0043] In the context of the present disclosure, the etching selectivity ratio mentioned above refers to the ratio of the etching rate of the grating teeth to the etching rate of the filling layer under the same etching conditions. The height of the grating prepared by the method of the embodiment of the present disclosure shows a gradual increase or decrease from the first direction to the second direction, and the grating tooth gap has a filling layer, which can significantly improve the brightness uniformity of the optical waveguide. In addition, the filling layer can also support the grating, provide a guarantee for the reliability of the grating, and make the grating less likely to collapse, thereby improving the preparation success rate and service life of the grating. It should be noted that the embodiment of the present disclosure does not specifically limit the first direction and the second direction. As an example, the first direction can be left, the second direction is right, or the first direction is right and the second direction is left. Furthermore, the embodiment of the present disclosure simultaneously etches the grating teeth and the filling layer, and can also make the etched surfaces of the grating teeth and the filling layer have the same shape, the two only differ in height, and greatly save etching time.
[0044] In some embodiments, the preset etching ratio can be set in the range of [0.8, 1.2], which is not specifically limited in the embodiments disclosed herein.
[0045] Combination of the above Figure 1 and Figure 6The grating preparation method 10 of some embodiments of the present disclosure is generally described. In the embodiments of the present disclosure, a filling layer is formed by first filling a material in the gap between the grating teeth. Then, the grating teeth and the filling layer in the grating area are simultaneously etched downward with a preset etching selection ratio, and finally a bottom-aligned height gradient grating including the filling layer is formed. The optical waveguide composed of the grating prepared according to such step operation can significantly improve the brightness uniformity. At the same time, the filling layer also supports the grating, which can improve the stability of the grating and make it less likely to collapse. However, it should be understood by those skilled in the art that Figure 1 The methods shown are exemplary rather than limiting, and those skilled in the art can make adjustments as needed.
[0046] Next, we will combine Figure 2 and Figure 7 Multiple embodiments and variations of the grating preparation method 10 of some embodiments of the present disclosure are further described.
[0047] See also Figure 2 and Figure 7 , Figure 2 is a flow chart of a grating preparation method 20 according to some embodiments of the present disclosure, Figure 7 Yes Execution Figure 2 Schematic diagram of the grating structure obtained after the corresponding steps in FIG. Figure 2 and Figure 7 As shown, first at step S201, method 20 plates an optical film layer on the surface of the substrate. Then, step S202 is performed, and at this step S202, method 20 forms an etching mask arranged at intervals on the surface of the optical film layer. Further, the process proceeds to step S203. At step S203, method 20 etches the optical film layer so that the optical film layer forms grating teeth. In the embodiment disclosed in the present invention, etching masks arranged at intervals are formed on the surface of the optical film layer to protect the optical film layer under the etching mask from being etched and from being damaged during the etching process of the optical film layer. Therefore, after executing step S203, the portion of the optical film layer where the etching mask is not formed is etched from top to bottom, and the portion where the etching mask is formed is retained, so that the optical film layer forms grating teeth with gaps.
[0048] In some embodiments, the aforementioned etching mask can be formed on the optical film layer by using photolithography technology or nanoimprint technology. Then, at step S202, method 20 can first apply photoresist glue or nanoimprint glue on the surface of the optical film layer. Then, photolithography technology or nanoimprint technology is used to form a periodically spaced photoresist pattern on the surface of the optical film layer as an etching mask. Specifically, photolithography technology is to form a photoresist pattern by exposing the surface of the optical film layer, while nanoimprint technology is to form a photoresist pattern by imprinting a mold printed with a photoresist pattern on the surface of the optical film layer.
[0049] The process then reaches step S204. At step S204, method 20 removes the etching mask on the surface of the optical film layer. The process then runs to step S205 and step S206 in sequence. At step S205, method 20 fills the gap between the grating teeth with material to form a filling layer, wherein the filling layer and the grating teeth are different materials. At step S206, method 20 synchronously etches downward the grating teeth and the filling layer in the grating area with a preset etching selectivity to form a bottom-aligned height gradient grating. The above steps S205 and S206 are the same or similar to steps S102 and S103 in method 10 described above. Those skilled in the art may refer to the corresponding specific implementation methods, which will not be elaborated here.
[0050] Combination of the above Figure 2 and Figure 7 The grating preparation method 20 of some embodiments of the present disclosure is generally described. The present disclosure embodiment forms an etching mask arranged at intervals on the surface of the optical film layer. Then the optical film layer is etched to form grating teeth with gaps on the optical film layer for grating preparation. However, it should be understood by those skilled in the art that Figure 2 The methods shown are exemplary rather than limiting, and those skilled in the art can make adjustments as needed.
[0051] For example, in some embodiments, after executing step S203, the method 20 may directly skip step S204, that is, the etching mask on the surface of the optical film layer is not removed, and step S205 is directly executed to fill the gaps between the grating teeth with materials to form a filling layer. After executing step S205, step S204 is executed again, and finally step S206 is executed.
[0052] Next, we will combine Figure 3 and Figure 8 The present disclosure further describes a plurality of embodiments and variations of the grating preparation method 20. However, those skilled in the art should know that the grating preparation method described below is also applicable to the method 10 described above.
[0053] See also Figure 3 and Figure 8 , Figure 3 is a flow chart of a grating preparation method 30 according to some embodiments of the present disclosure, Figure 8 Yes Execution Figure 3 Schematic diagram of the grating structure obtained after the corresponding steps in FIG. Figure 3As shown, at step S301, method 30 plates an optical film layer on the surface of the substrate. Then at step S302, method 30 forms an etching mask arranged at intervals on the surface of the optical film layer. At step S303, method 30 etches the optical film layer so that the optical film layer forms grating teeth. After the grating teeth are formed, the process runs to step S304. At this step S304, method 30 removes the etching mask on the surface of the optical film layer. Then step S305 is further performed. At step S305, method 30 fills the gap between the grating teeth with material to form a filling layer, wherein the filling layer and the grating teeth are different materials. It should be noted that steps S301 to S305 are the same or similar to the corresponding steps in method 30 described above, and will not be repeated here.
[0054] Then the process continues to run step S306. At step S306, the method 30 forms a grating pattern on the surface of the grating teeth in the grating area, and forms an etching mask on the surface of the non-grating area, wherein the non-grating area is located around the grating area. It can be understood that the grating area includes grating teeth and a filling layer, so after the grating pattern is formed on the surface of the grating teeth, the grating teeth and the filling layer can be accurately identified, and then the grating teeth and the filling layer are etched at corresponding etching rates respectively.
[0055] In some embodiments, photoresist or nanoimprint glue can be coated on the surface of the substrate, and then a grating pattern can be formed on the surface of the grating teeth in the grating area using photolithography or nanoimprint technology, and then the photoresist or nanoimprint glue on the surface of the filling layer can be removed, and the photoresist or nanoimprint glue on the surface of the non-grating area can be retained as an etching mask. The embodiments disclosed herein do not specifically limit this.
[0056] In some embodiments, the width of the non-grating area can be set to be greater than the width of the grating teeth, or can be set to be consistent with the width of the grating teeth. The disclosed embodiments do not specifically limit this, and those skilled in the art can modify it as needed.
[0057] Finally, the process reaches step S307. At step S307, the method 30 synchronously etches the grating teeth and the filling layer in the grating region downward with a preset etching selectivity to form a bottom-aligned grating with a gradient height. In the disclosed embodiment, the etching mask formed on the surface of the non-grating region can have a certain thickness so that the height of the non-grating region is greater than the height of the grating region. Based on this, when etching the grating region, the etching mask can protect the non-grating region from being affected by the etching process of the grating region, and can prevent the etching waste of the grating region from splashing.
[0058] In some embodiments, after executing step S307, the process may further execute step S308. In step S308, method 30 removes the etching mask of the non-grating area.
[0059] Combination of the above Figure 3 and Figure 8 The grating preparation method 30 of some embodiments of the present disclosure is generally described. In the embodiments of the present disclosure, a grating pattern is formed on the surface of the grating teeth in the grating area, and an etching mask is formed on the surface of the non-grating area of the substrate. According to such step operation, when the grating area is etched, the etching mask can protect the non-grating area from being affected by the etching process of the grating area, and at the same time avoid the splashing of the etching waste in the grating area. However, it should be understood by those skilled in the art that Figure 3 The methods shown are exemplary rather than limiting, and those skilled in the art can make adjustments as needed.
[0060] Next, continue to combine Figure 4 and Fig. 9 Multiple embodiments and variations of the grating preparation method 30 of some embodiments of the present disclosure are further described, which are also applicable to the method 10 and the method 20 described above.
[0061] See also Figure 4 and Fig. 9 , Figure 4 is a flow chart of a grating preparation method 40 according to some embodiments of the present disclosure, Fig. 9 Yes Execution Figure 4 Schematic diagram of the grating structure obtained after the corresponding steps in FIG. Figure 4 and Fig. 9 As shown, the process first executes steps S401 to S408 in sequence, and these steps are the same or similar to steps S301 to S308 in the aforementioned method 30, and are not repeated here.
[0062] In some embodiments, after executing step S408, step S409 may be further executed. At step S409, method 40 removes the optical film layer in the non-grating area. Step S409 may be selectively executed, and the disclosed embodiment does not specifically limit this. In other embodiments, no non-grating area is provided, and step S409 may be omitted.
[0063] In some embodiments, after executing step S408 or step S409, step S410 may be further executed. At step S410, method 40 removes the filling layer to form a bottom-aligned height gradient grating. It is understood that the grating prepared after step S410 does not include a filling layer. Similarly, the filling layer may be etched by a wet process to achieve the purpose of removing the filling layer.
[0064] Combination of the above Figure 4 and Fig. 9The grating preparation method 40 of some embodiments of the present disclosure is generally described. After forming a bottom-aligned height gradient grating including a filling layer, the present disclosure embodiment removes the etching mask and the optical film layer in the non-grating area, and / or removes the filling layer, thereby forming a bottom-aligned height gradient grating without a filling layer. The brightness uniformity of the optical waveguide formed by the grating can still be improved. However, it should be understood by those skilled in the art that Figure 4 The methods shown are exemplary rather than limiting, and those skilled in the art can make adjustments as needed.
[0065] For example, in some embodiments, at step S402, method 40 can form an etching mask with spaced arrangement and the same width on the surface of the optical film layer. Furthermore, after executing step S403, grating teeth with spaced arrangement and the same width can be obtained. Thereafter, when executing step S406, method 40 can directly form a grating pattern on the grating tooth surface of the substrate. It can be understood that in this scenario, grating patterns are formed on the grating tooth surfaces. In other words, all grating teeth on the substrate can be used for grating preparation, that is, there is no non-grating area. Therefore, in step S407, method 20 synchronously etches downward the grating teeth and the filling layer with a preset etching selectivity. Furthermore, after executing step S407, the grating that originally required executing step S409 to obtain can be directly obtained.
[0066] See also Figure 5 , Figure 5 Schematic diagram of the structure of the grating structure 50 of some embodiments of the present disclosure. Figure 5 As shown in Figure (a), the grating structure 50 may include a substrate 501, a grating 502 disposed on the substrate 501, and a filling layer 503 disposed between the gratings. In some embodiments, the filling layer 503 and the grating 502 are made of different materials, the heights of the grating 502 and the filling layer 503 are gradually increased or decreased, and the bottoms of the grating 502 and the filling layer 503 are aligned. In the disclosed embodiment, the grating structure 50 is set to have a gradual height change, and the filling layer 503 is disposed between the gratings 502, which can achieve the effect of improving the brightness uniformity of the optical waveguide including the grating structure 50. In addition, the filling layer 503 can also support the grating 502, so that the grating structure maintains stability and is not easy to collapse.
[0067] In some embodiments, the grating 502 and the filling layer 503 on the substrate 501 are combined to form a trapezoidal structure whose height gradually increases or decreases from the first direction to the second direction. It should be noted that the first direction and the second direction are not specifically limited in the disclosed embodiments. As an example, the first direction can be left and the second direction can be right, or the first direction can be right and the second direction can be left.
[0068] In some embodiments, the grating 502 may or may not be aligned with the bottom of the filling layer 503, as long as the height of the grating 502 and the upper surface of the filling layer 503 gradually increases or decreases. The disclosed embodiments do not make specific limitations on this, and technicians in this field can make choices based on their needs.
[0069] In some embodiments, Figure 5 As shown in the middle (b), the grating structure 50 may be a wedge-shaped structure with a depression in the middle and protrusions on both sides, wherein the depression in the middle is the grating region, including the grating 502 and the filling layer 503, and the protrusions around the grating region are the non-grating region. At this time, the grating 502 and the filling layer 503 in the grating region are combined to form a trapezoidal structure whose height gradually increases or decreases from the first direction to the second direction.
[0070] In some embodiments, Figure 5 As shown in (c), the grating structure 50 may only include a substrate 501 and gratings 502 arranged at intervals on the substrate, wherein the height of the gratings is gradually increased or decreased, which can still achieve the effect of improving the brightness uniformity of the optical waveguide containing the gratings 502.
[0071] In some embodiments, the grating structure 50 may be manufactured using any of the embodiments of the grating manufacturing method described above.
[0072] In some embodiments of the present disclosure, an optical waveguide is also provided, which includes a grating obtained by any of the grating preparation methods described above or includes any of the grating structures described above.
[0073] Furthermore, the optical waveguide may also include an in-coupling grating, a turning grating, and an out-coupling grating. At least one of the in-coupling grating, the turning grating, and the out-coupling grating may be a grating prepared by any of the grating preparation methods described above or include any of the grating structures described above. According to such a setting, the bottoms of the gratings in the optical waveguide can be aligned and the heights can be gradually changed, so as to significantly improve the brightness uniformity of the optical waveguide, and there is no need to divide the height regions of the gratings during preparation, thereby reducing the preparation complexity of the optical waveguide.
[0074] Although multiple embodiments of the present disclosure have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art may think of many changes, modifications, and alternatives without departing from the thought and spirit of the present disclosure. It should be understood that in the process of practicing the present disclosure, various alternatives to the embodiments of the present disclosure described herein may be adopted. The attached claims are intended to define the scope of protection of the present disclosure, and therefore cover equivalents or alternatives within the scope of these claims.
Claims
1. A grating preparation method, characterized in that: include: Plating an optical film layer on the surface of the substrate, and etching the optical film layer so that the optical film layer forms grating teeth; Filling material into the gaps between the grating teeth to form a filling layer, wherein the filling material and the grating teeth are different materials; as well as The grating teeth and the filling layer in the grating area are synchronously etched downward with a preset etching selection ratio to form a bottom-aligned height-gradient grating.
2. The method according to claim 1, characterized in that: The step of coating an optical film layer on the surface of the substrate and etching the optical film layer so as to form grating teeth on the optical film layer comprises: Coating a layer of the optical film layer on the surface of the substrate; Forming etching masks arranged at intervals on the surface of the optical film layer; and The optical film layer is etched so that the optical film layer forms the grating teeth.
3. The method according to claim 2, characterized in that The etching masks arranged at intervals on the surface of the optical film layer include: Coating photoresist glue or nanoimprint glue on the surface of the optical film layer; and A photoresist pattern arranged at intervals is formed on the surface of the optical film layer by using photolithography technology or nanoimprint technology to serve as the etching mask.
4. The method according to claim 2, characterized in that: Before filling the gaps between the grating teeth with a material to form a filling layer, the method further comprises: The etching mask on the surface of the optical film layer is removed.
5. The method according to claim 1, characterized in that Filling the gaps between the grating teeth with material to form a filling layer comprises: filling the gaps between the grating teeth with material; and The excess filling material exceeding the height of the grating teeth is removed to form the filling layer.
6. The method according to claim 1, characterized in that Before synchronously etching downward the grating teeth and the filling layer in the grating region with a preset etching selection ratio to form a bottom-aligned height-gradient grating, the method further comprises: A grating pattern is formed on the surface of the grating teeth in the grating area, and an etching mask is formed on the surface of the non-grating area, wherein the non-grating area is located around the grating area.
7. The method according to claim 6, characterized in that After synchronously etching downward the grating teeth and the filling layer in the grating region with a preset etching selection ratio to form a bottom-aligned height-gradient grating, the method further comprises: The etching mask on the surface of the non-grating area is removed.
8. The method according to claim 7, characterized in that After removing the etching mask on the surface of the non-grating area, the method further comprises: The optical film layer in the non-grating area is removed.
9. The method according to any one of claims 1 to 8, characterized in that: After synchronously etching downward the grating teeth and the filling layer in the grating region with a preset etching selection ratio to form a bottom-aligned height-gradient grating, the method further comprises: The filling layer is removed to form a bottom-aligned height-gradient grating.
10. The method according to claim 1, characterized in that The grating teeth are in the shape of straight teeth or helical teeth.
11. The method according to claim 1, characterized in that: The preset etching ratio is in the range of [0.8, 1.2].
12. A grating structure, characterized in that: include: substrate; A grating disposed on the substrate; as well as A filling layer is arranged in the gap between the gratings, wherein the filling layer and the gratings are made of different materials, the heights of the gratings and the filling layer are gradually increased or decreased, and the bottoms of the gratings and the filling layer are aligned.
13. An optical waveguide, characterized in that: The grating comprises a grating obtained by the grating preparation method according to any one of claims 1 to 11 or comprises the grating structure according to claim 12.