Grating structure and preparation method thereof, waveguide structure, display panel, and display device

Abstract

Embodiments of the present application provide a grating structure, a preparation method thereof, a waveguide structure, a display panel and a display device. The grating structure comprises a substrate and a blazed grating arranged on one side of the substrate. The blazed grating comprises a plurality of grating substructures arranged in sequence and at intervals along a direction parallel to the substrate. The first-order diffraction efficiency of the blazed grating is at most improved by 4 times by setting parameters of the blazed grating. The parameters of the blazed grating include at least one of a period, a duty cycle, a material of the grating substructure, a height and an inclination angle. Embodiments of the present application can improve the diffraction efficiency of the grating.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular, the present application relates to a grating structure and a preparation method thereof, a waveguide structure, a display panel and a display device. BACKGROUND

[0002] With the vigorous development of technologies such as augmented reality (AR) and virtual reality (VR) brought about by the "meta-universe fever", AR and VR technologies have gradually attracted widespread attention, and these technologies are widely used in fields such as product advertising, mobile shopping, multi-screen interaction, location navigation and gaming.

[0003] The surface relief grating (SRG) diffractive optical waveguide scheme is considered to be the most promising mainstream AR optical waveguide lens preparation scheme in the future due to its easy mass production and excellent performance. However, the current SRG diffractive optical waveguide technology has problems such as low grating diffraction efficiency, which needs to be solved urgently. SUMMARY

[0004] The present application proposes a grating structure and a preparation method thereof, a waveguide structure, a display panel and a display device to improve the grating diffraction efficiency.

[0005] In a first aspect, the embodiments of the present application provide a grating structure, comprising:

[0006] a substrate;

[0007] a blazed grating disposed on one side of the substrate, the blazed grating comprising a plurality of grating substructures, the plurality of grating substructures being sequentially and spaced apart along a direction parallel to the substrate;

[0008] The parameters of the blazed grating are set so that the first-order diffraction efficiency of the blazed grating is at most improved by 4 times.

[0009] The parameters of the blazed grating include at least one of a period, a duty cycle, a material, a height and an inclination angle of the grating substructure.

[0010] Optionally, the grating structure further comprises a first film layer disposed on a side of the blazed grating away from the substrate;

[0011] The first film layer comprises a plurality of first sub-film layers, the plurality of first sub-film layers are one-to-one corresponding to the plurality of grating substructures, and the orthographic projection of the first sub-film layer on the substrate coincides with the orthographic projection of the grating substructure on the substrate.

[0012] The refractive index of the first sub-film layer is greater than or equal to the refractive index of the grating substructure.

[0013] The first sub-film layer has a first height along a direction perpendicular to the substrate.

[0014] Optionally, the grating structure further comprises a second film layer, the second film layer is arranged on a side of the first film layer away from the substrate.

[0015] The second film layer comprises a plurality of second sub-film layers, the plurality of second sub-film layers are arranged one-to-one corresponding to the plurality of grating sub-structures, and a projection of the second sub-film layer on the substrate coincides with a projection of the grating sub-structure on the substrate.

[0016] The refractive index of the second sub-film layer is smaller than the refractive index of the first sub-film layer.

[0017] The second sub-film layer has a second height along a direction perpendicular to the substrate.

[0018] Optionally, the first height is greater than or equal to 10 nm and less than or equal to 100 nm; and / or,

[0019] The second height is greater than or equal to 50 nm and less than or equal to 100 nm.

[0020] Optionally, the grating sub-structure has a bottom wall facing the substrate, a top wall facing away from the substrate, a first side wall, and a second side wall, the bottom wall is connected to the top wall through the first side wall, and the top wall is connected to the bottom wall through the second side wall.

[0021] A projection of the top wall on the substrate is located within a projection of the bottom wall on the substrate.

[0022] At least part of the first side wall is arranged at a right angle or an acute angle with a preset plane; and / or, at least part of the second side wall is arranged at an acute angle with the preset plane, and the preset plane is parallel to the substrate.

[0023] Optionally, the first side wall comprises a first wall segment, one end of the first wall segment is connected to the bottom wall, the other end of the first wall segment is connected to the top wall, the first wall segment has a first included angle with the preset plane, and the first included angle is a right angle or an acute angle; in a cross section perpendicular to the substrate, a cross-sectional shape of the first wall segment is linear, curved, or bent.

[0024] And / or,

[0025] The second side wall comprises a second wall segment, one end of the second wall segment is connected to the bottom wall, the other end of the second wall segment is connected to the top wall, the second wall segment has a second included angle with the preset plane, and the second included angle is an acute angle; in a cross section perpendicular to the substrate, a cross-sectional shape of the second wall segment is linear, curved, or bent.

[0026] Optionally, the first included angle is greater than or equal to 45° and less than or equal to 90°; and / or,

[0027] The second included angle is greater than or equal to 10° and less than or equal to 50°.

[0028] Optionally, the first side wall comprises a first wall segment and a third wall segment, one end of the first wall segment is connected with the top wall, and the other end of the first wall segment away from the top wall is connected with the bottom wall through the third wall segment; the first wall segment has a first included angle with the preset plane, and the first included angle is a right angle or an acute angle; in a cross section perpendicular to the substrate, the cross section shape of the first wall segment is linear, curved or bent; the third wall segment is perpendicular to the substrate.

[0029] and / or,

[0030] The second side wall comprises a second wall segment and a fourth wall segment, one end of the second wall segment is connected with the top wall, and the other end of the second wall segment away from the top wall is connected with the bottom wall through the fourth wall segment; the second wall segment has a second included angle with the preset plane, and the second included angle is an acute angle; in a cross section perpendicular to the substrate, the cross section shape of the second wall segment is linear, curved or bent; the fourth wall segment is perpendicular to the substrate.

[0031] Optionally, the grating structure further comprises a first film layer, the first film layer comprises a first sub-film layer, and the first sub-film layer has a first height in a direction perpendicular to the substrate.

[0032] The first height is greater than or equal to 50 nm and less than or equal to 100 nm.

[0033] Optionally, the period of the blazed grating is greater than or equal to 300 nm and less than or equal to 700 nm; or,

[0034] The duty cycle of the blazed grating is greater than or equal to 0.2 and less than or equal to 0.9; or,

[0035] The height of the grating sub-structure in a direction perpendicular to the substrate is greater than or equal to 220 nm and less than or equal to 580 nm.

[0036] In a second aspect, the embodiments of the present application provide a waveguide structure, comprising a waveguide medium layer, the waveguide medium layer having a first region and a second region; further comprising:

[0037] a coupling-in grating and a coupling-out grating; or,

[0038] a coupling-in grating, a coupling-out grating and a turning grating, the waveguide medium layer further having a third region;

[0039] Wherein:

[0040] The orthographic projection of the coupling-in grating on the waveguide medium layer is located in the first region;

[0041] The orthographic projection of the coupling-out grating on the waveguide medium layer is located in the second region;

[0042] The orthographic projection of the turning grating on the waveguide medium layer is located in the third region;

[0043] At least one of the in-coupling grating, the out-coupling grating, and the turning grating adopts the grating structure of the first aspect.

[0044] In a third aspect, an embodiment of the present application provides a display panel, comprising a substrate, and

[0045] The grating structure of the first aspect is arranged on one side of the substrate; or

[0046] The waveguide structure of the second aspect is arranged on one side of the substrate.

[0047] In a fourth aspect, an embodiment of the present application provides a display device, comprising the display panel of the third aspect.

[0048] In a fifth aspect, an embodiment of the present application provides a preparation method of a grating structure, comprising:

[0049] providing a substrate;

[0050] manufacturing a blazed grating on one side of the substrate, the blazed grating comprising a plurality of grating substructures, the plurality of grating substructures being arranged in sequence and at intervals along a direction parallel to the substrate;

[0051] by setting parameters of the blazed grating, a first-order diffraction efficiency of the blazed grating is at most improved by 4 times;

[0052] The parameters of the blazed grating comprise at least one of a period, a duty cycle, a material, a height, and an inclination angle of the grating substructure.

[0053] Optionally, the preparation method of the grating structure further comprises:

[0054] manufacturing a first film layer on a side of the blazed grating away from the substrate, the first film layer comprising a plurality of first sub-film layers, the plurality of first sub-film layers being arranged in one-to-one correspondence with the plurality of grating substructures, a normal projection of the first sub-film layer on the substrate coincides with a normal projection of the grating substructure on the substrate, and a refractive index of the first sub-film layer is greater than or equal to a refractive index of the grating substructure;

[0055] or

[0056] manufacturing a first film layer on a side of the blazed grating away from the substrate, the first film layer comprising a plurality of first sub-film layers, the plurality of first sub-film layers being arranged in one-to-one correspondence with the plurality of grating substructures, a normal projection of the first sub-film layer on the substrate coincides with a normal projection of the grating substructure on the substrate, and a refractive index of the first sub-film layer is greater than or equal to a refractive index of the grating substructure;

[0057] A second film layer is made on a side of the first film layer away from the substrate, and the second film layer includes a plurality of second sub-film layers, the plurality of second sub-film layers are arranged one by one corresponding to the plurality of grating sub-structures, and a normal projection of the second sub-film layer on the substrate coincides with a normal projection of the grating sub-structure on the substrate; a refractive index of the second sub-film layer is less than or equal to a refractive index of the first sub-film layer.

[0058] The technical scheme provided by the embodiments of the present application has the following beneficial technical effects:

[0059] In the embodiments of the present application, the plurality of grating sub-structures of the blazed grating are arranged in sequence and spaced apart along a direction parallel to the substrate, and by setting parameters (including at least one of a period, a duty cycle, a material of the grating sub-structure, a height, and an inclination angle) of the blazed grating, most of the light energy of the blazed grating is concentrated in a preset direction, i.e., concentrated on a certain preset spectral level, thereby realizing control of the light direction, and the intensity of the spectrum is maximum in the preset direction. By setting the parameters of the blazed grating, the embodiments of the present application can achieve the purpose of optimizing the diffraction efficiency and brightness uniformity of the blazed grating, increase the utilization rate of light, and enable the first-order diffraction efficiency of the blazed grating to be at most increased by 4 times.

[0060] Additional aspects and advantages of the present application will be made apparent from the following description, which, taken together with the accompanying drawings, describes and illustrates a few embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0061] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken together with the accompanying drawings, in which:

[0062] Figure 1 is a top view of a waveguide structure in the related art;

[0063] Figure 2 is Figure 1 is a diffraction efficiency curve of a rectangular grating;

[0064] Figure 3 is a flowchart of a preparation method of a grating structure provided by the embodiments of the present application;

[0065] Figures 4 to 7 is a structure schematic diagram of a grating structure provided by the first embodiment of the present application; Figure 7 is a structure schematic diagram of a grating structure provided by the first embodiment of the present application;

[0066] Figures 8 to 19 is a structure schematic diagram of a grating structure provided by the first embodiment of the present application; Figure 19 is a structure schematic diagram of a grating structure provided by the first embodiment of the present application;

[0067] Figures 4 to 7 、 Figure 20 Structure schematic diagrams of a grating structure in different processes in a preparation method of the grating structure provided in Embodiment Two of the present application, wherein, Figure 20 A structure schematic diagram of a grating structure provided in Embodiment Two of the present application;

[0068] Figures 21 to 24 Structure schematic diagrams of a grating structure in different processes in a preparation method of the grating structure provided in Embodiment Three of the present application, wherein, Figure 24 A structure schematic diagram of a grating structure provided in Embodiment Three of the present application;

[0069] Figure 25 A structure schematic diagram of a waveguide structure provided in the present application;

[0070] Figure 26 Another structure schematic diagram of a waveguide structure provided in the present application;

[0071] Figure 27 Still another structure schematic diagram of a waveguide structure provided in the present application;

[0072] Figure 28 A diffraction efficiency curve diagram of a grating structure provided in Embodiment One of the present application;

[0073] Figure 29 A diffraction efficiency curve diagram of a grating structure provided in Embodiment Two of the present application;

[0074] Figure 30 A diffraction efficiency curve diagram of a grating structure provided in Embodiment Three of the present application;

[0075] Figure 31 A structure schematic diagram of a display panel provided in the present application.

[0076] Reference signs:

[0077] 100-grating structure; 10-substrate; 20-blazed grating; 21-grating substructure; 22-bottom wall; 23-top wall; 24-first side wall; 25-second side wall; 26-first wall segment; 27-second wall segment; 28-third wall segment; 29-fourth wall segment; 30-first film layer; 31-first sub-film layer; 40-second film layer; 41-second sub-film layer; 51-optical resin film layer; 52-first glass substrate; 53-photolithography film layer; 54-main mold template; 55-soft mold template; 56-mother mold template; 57-hollow pattern; 58-third glass substrate; 59-mold template adhesive layer; 200-waveguide structure; 210-waveguide medium layer; 220-coupling-in grating; 230-coupling-out grating; 240-turning grating; 250-light emitting device or light propagating device. Detailed Implementation

[0078] The embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the embodiments described below with reference to the accompanying drawings are exemplary descriptions for explaining the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions of the embodiments of this application.

[0079] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this application means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude implementations of other features, information, data, steps, operations, elements, components, and / or combinations thereof supported by this art. It should be understood that when we say an element is “connected” or “coupled” to another element, the element may be directly connected or coupled to the other element, or it may mean that the element and the other element are connected through an intermediate element. Furthermore, “connected” or “coupled” as used herein may include wireless connection or wireless coupling. The term “and / or” as used herein means at least one of the items defined by the term; for example, “A and / or B” may be implemented as “A,” or as “B,” or as “A and B.”

[0080] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0081] First, let's introduce and explain several terms used in this application:

[0082] A grating is an optical device consisting of a large number of parallel slits of equal width and spacing. Commonly used gratings are made by etching numerous parallel lines on a glass plate. The lines are opaque, while the smooth areas between the lines allow light to pass through, essentially acting as slits.

[0083] Blazed grating: When a grating is etched with serrated grooves, the light energy of the grating is concentrated in a predetermined direction, i.e., a certain spectral level. The intensity of the spectrum is greatest when detected in this direction; this phenomenon is called blaze, and such a grating is called a blazed grating. In such a blazed grating, the groove surface that performs diffraction is a smooth plane, forming an angle with the grating surface, called the blaze angle.

[0084] Grating period: refers to the sum of the slit width and the width of the opaque portion between two adjacent slits along the direction parallel to the grating.

[0085] Duty cycle of grating: refers to the ratio of the slit width to the grating period.

[0086] Field of view (FOV): Field of view is also called field of view in optical engineering, and the size of the field of view determines the field of view of the optical instrument.

[0087] The related art will be described below Figure 1 and Figure 2 The related art will be described below

[0088] As Figure 1 shown, the display system based on the surface relief grating (SRG) diffractive optical waveguide scheme generally consists of a micro display, a collimating eyepiece group, a waveguide medium layer 210', an input coupling grating (i.e. a coupling-in grating) 220', a turning coupling grating (i.e. a turning grating, not shown in the figure), and an output coupling grating (i.e. a coupling-out grating) 230', wherein the coupling-in grating 220', the turning grating, and the coupling-out grating 230' are placed on the same transparent waveguide medium layer 210'. The basic principle of the display system is that the micro display outputs virtual image information, which is converted into collimated light by the collimating eyepiece group, changes the propagation direction of the light into the waveguide medium layer 210' through the coupling-in grating 220' placed on the waveguide medium layer 210', and the parallel light of each field of view satisfies the total reflection condition in the waveguide medium layer 210'. After the propagation in the waveguide medium layer 210', the light changes the propagation direction through the turning grating, and is finally output from the coupling-out grating 230', so that the light no longer satisfies the total reflection condition in the waveguide medium layer 210', and is emitted from the waveguide medium layer 210'. The light beam expands along the propagation direction and enters the observer's eye after being coupled out from the waveguide medium layer 210', achieving the purpose of pupil expansion.

[0089] It should be noted that the grating diffraction order includes 0th order, ±1st order, etc., and the energy of different orders is different. The grating of the SRG AR optical waveguide sheet mainly includes rectangular grating, inclined grating and blazed grating. As Figure 1 and Figure 2 shown, Figure 1 a top view of an augmented reality optical waveguide sheet using a coupling-in grating and a coupling-out grating in the related art is shown, which can only use -1st order light, resulting in a large amount of energy loss; Figure 2 a diffraction efficiency curve diagram of a rectangular grating in the related art under FOV of ±16° is shown, and Figure 2 the -1st order diffraction efficiency is calculated to be 16% (as Figure 2 shown, Figure 2 the ordinate represents the diffraction efficiency, and the abscissa represents the diffraction angle. Alternatively, the diffraction angle is the field of view; Figure 2The curve a is a corresponding relationship curve of a diffraction angle and a diffraction efficiency when the augmented reality light waveguide sheet is diffracted at a-1 order, the curve b is a corresponding relationship curve of the diffraction angle and the diffraction efficiency when the augmented reality light waveguide sheet is diffracted at 0 order, and the curve c is a corresponding relationship curve of the diffraction angle and the diffraction efficiency when the augmented reality light waveguide sheet is diffracted at +1 order.

[0090] Currently, problems of the SRG diffraction light waveguide technology mainly include a small field of view, a low grating diffraction efficiency, and poor brightness uniformity, and the like, which need to be solved and improved.

[0091] The grating structure, the preparation method thereof, the waveguide structure, the display panel, and the display device provided in the present application aim to solve at least one technical problem of the prior art.

[0092] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail below with specific embodiments. It should be pointed out that the following embodiments can be mutually referenced, borrowed or combined, and the same terms, similar features and similar implementation steps in different embodiments will not be described repeatedly.

[0093] The grating structure 100 provided in the present application embodiment has a structure as shown in Figure 6 、 Figure 7 、 Figures 18 to 20 、 Figure 23 and Figure 24 The grating structure 100 provided in the present application embodiment has a structure as shown in

[0094] In the present application embodiment, the substrate 10 supports the blazed grating 20. The plurality of grating substructures 21 of the blazed grating 20 are sequentially and spacedly arranged along a direction parallel to the substrate 10. By setting the parameters of the blazed grating 20 (including at least one of the period d, the duty cycle, the material of the grating substructure 21, the height h, and the inclination angle), most of the light energy of the blazed grating 20 is concentrated in a preset direction, i.e., in a certain preset spectral order, thereby achieving control of the light direction, and the intensity of the spectrum in the preset direction is the maximum. By setting the parameters of the blazed grating 20, the present application embodiment can achieve the purpose of optimizing the diffraction efficiency and the brightness uniformity of the blazed grating 20, and increase the utilization rate of light. Compared with the conventional grating, the first-order diffraction efficiency of the blazed grating 20 of the present application embodiment can be increased by at most 4 times.

[0095] It should be noted that in the embodiments of the present application, the first-order diffraction efficiency of the blazed grating 20 includes -1 order diffraction efficiency and +1 order diffraction efficiency.

[0096] Optionally, as shown in Figure 6 and Figure 23 In the embodiments of the present application, the grating substructure 21 has a bottom wall 22 facing the substrate 10, a top wall 23 facing away from the substrate 10, a first side wall 24 and a second side wall 25, the bottom wall 22 is connected to the top wall 23 through the first side wall 24, and the top wall 23 is connected to the bottom wall 22 through the second side wall 25; the orthographic projection of the top wall 23 on the substrate 10 is located within the orthographic projection of the bottom wall 22 on the substrate 10. Among them: at least part of the first side wall 24 is arranged at a right angle or an acute angle with the preset plane; at least part of the second side wall 25 is arranged at an acute angle with the preset plane, and the preset plane is parallel to the substrate 10.

[0097] In the embodiments of the present application, the bottom wall 22, the first side wall 24, the top wall 23, the second side wall 25, and the bottom wall 22 are sequentially connected, the orthographic projection of the top wall 23 on the substrate 10 is located within the orthographic projection of the bottom wall 22 on the substrate 10, and at least part of the first side wall 24 and / or at least part of the second side wall 25 are arranged to be inclined or curved or bent relative to the preset plane parallel to the substrate 10, in order to connect the bottom wall 22 and the top wall 23; Specifically, at least part of the first side wall 24 is arranged at a right angle or an acute angle with the preset plane; at least part of the second side wall 25 is arranged at an acute angle with the preset plane, and through this arrangement, the light energy can be more efficiently shifted and concentrated to the required diffraction order, achieving the purpose of optimizing the diffraction efficiency and brightness uniformity of the blazed grating 20, and increasing the utilization of light.

[0098] It should be noted that in the embodiments of the present application, the orthographic projection of the top wall 23 on the substrate 10 is located within the orthographic projection of the bottom wall 22 on the substrate 10 means that the orthographic projection of the bottom wall 22 on the substrate 10 can cover the orthographic projection of the top wall 23 on the substrate 10, and the area of the orthographic projection of the bottom wall 22 on the substrate 10 is greater than the area of the orthographic projection of the top wall 23 on the substrate 10.

[0099] It should be noted that "at least part of the first side wall 24" in the arrangement of at least part of the first side wall 24 at a right angle or an acute angle with the preset plane includes part of the first side wall 24 (such as Figure 23 In a specific embodiment as shown in Figure 6In another specific embodiment shown in the figure, the first side wall 24 comprises a first wall segment 26, wherein the first wall segment 26 is arranged at an acute angle with the preset plane. The "at least part of the second side wall 25" has similar meaning as "at least part of the first side wall 24", which will not be repeated here.

[0100] Of course, in some optional embodiments of the present application, only at least part of the first side wall 24 can be arranged at a right angle or an acute angle with the preset plane, or only at least part of the second side wall 25 can be arranged at an acute angle with the preset plane, and the preset plane is parallel to the substrate 10.

[0101] Optionally, in the embodiments of the present application, the material of the grating substructure 21 is an optical resin material.

[0102] Optionally, in the embodiments of the present application, the substrate 10 is a glass substrate, and specifically, the material of the substrate 10 is white glass.

[0103] In a specific embodiment (Embodiment I) of the present application, as shown in the figure, Figure 6 the first side wall 24 comprises a first wall segment 26, one end of the first wall segment 26 is connected with the bottom wall 22, the other end of the first wall segment 26 is connected with the top wall 23, the first wall segment 26 has a first included angle A1 with the preset plane, and the first included angle A1 is a right angle or an acute angle; in the cross section perpendicular to the substrate 10, the cross-sectional shape of the first wall segment 26 is linear, i.e., the first wall segment 26 is arranged obliquely relative to the substrate 10. Through this arrangement, the light energy can be more efficiently shifted and concentrated to the desired diffraction order, achieving the purpose of optimizing the diffraction efficiency and brightness uniformity of the blazed grating 20, and increasing the utilization of light.

[0104] Of course, in an optional embodiment of the present application, the cross-sectional shape of the first wall segment 26 in the cross section perpendicular to the substrate 10 can be curved or bent according to actual needs.

[0105] Optionally, as shown in the figure, Figure 6 in the embodiments of the present application, the first included angle A1 is greater than or equal to 45° and less than or equal to 90°.

[0106] When the first included angle A1 is less than 45°, the light energy concentration effect is reduced, and the diffraction efficiency and brightness uniformity of the blazed grating 20 are limited in the degree of improvement or optimization; when the first included angle A1 is greater than 90°, the processing difficulty and production cost will be increased.

[0107] The first included angle A1 is greater than or equal to 45° and less than or equal to 90°, so that the light energy can be effectively offset and concentrated to the required diffraction order, the diffraction efficiency and the brightness uniformity of the blazed grating 20 are improved or optimized, the utilization rate of light is increased, and the blazed grating 20 is easy to manufacture, has low processing difficulty and low production cost.

[0108] Optionally, as shown in Figure 6 In the embodiment of the present application, the second side wall 25 includes a second wall segment 27, one end of the second wall segment 27 is connected with the bottom wall 22, the other end of the second wall segment 27 is connected with the top wall 23, the second wall segment 27 has a second included angle A2 with the preset plane, and the second included angle A2 is an acute angle; in the cross section perpendicular to the substrate 10, the cross-sectional shape of the second wall segment 27 is linear, that is, the second wall segment 27 is inclined relative to the substrate 10. Through this setting mode, the light energy can be more efficiently offset and concentrated to the required diffraction order, the purpose of optimizing the diffraction efficiency and the brightness uniformity of the blazed grating 20 is achieved, and the utilization rate of light is increased.

[0109] Of course, in an optional embodiment of the present application, the cross-sectional shape of the second wall segment 27 in the cross section perpendicular to the substrate 10 can also be curved or bent according to actual needs.

[0110] Optionally, as shown in Figure 6 In the embodiment of the present application, the second included angle A2 is greater than or equal to 10° and less than or equal to 50°.

[0111] When the second included angle A2 is less than 10°, the light energy concentration effect is reduced, and the diffraction efficiency and the brightness uniformity of the blazed grating 20 are limited in improving or optimizing; when the second included angle A2 is greater than 50°, the processing difficulty and the production cost are increased.

[0112] The second included angle A2 is greater than or equal to 10° and less than or equal to 50°, so that the light energy can be effectively offset and concentrated to the required diffraction order, the diffraction efficiency and the brightness uniformity of the blazed grating 20 are improved or optimized, the utilization rate of light is increased, and the blazed grating 20 is easy to manufacture, has low processing difficulty and low production cost.

[0113] Optionally, as shown in Figure 6 , Figure 7 , Figures 18 to 20 In the embodiment of the present application, the cross-sectional shape of the grating substructure 21 in the cross section perpendicular to the substrate 10 is trapezoidal.

[0114] Optionally, as shown in Figure 6As shown in the embodiment of this application, the period d of the blazed grating 20 is greater than or equal to 300 nm and less than or equal to 700 nm. By setting the period d of the grating substructure 21, the grating structure can have a higher diffraction efficiency.

[0115] It should be noted that in this embodiment, the period d of the grating substructure 21 is the same as the period of the blazed grating 20, and its specific meaning is similar to that of the grating period mentioned above, so it will not be repeated here.

[0116] Optionally, in this embodiment, the duty cycle of the blazed grating 20 is greater than or equal to 0.2 and less than or equal to 0.9. By setting the duty cycle of the grating substructure 21, the grating structure can have higher diffraction efficiency.

[0117] Optionally, such as Figure 6 As shown in the embodiment of this application, the height h of the grating substructure 21 along the direction perpendicular to the substrate 10 is greater than or equal to 220 nm and less than or equal to 580 nm. By setting the height h of the grating substructure 21 along the direction perpendicular to the substrate 10, the grating structure can have higher diffraction efficiency.

[0118] It should be noted that, in the embodiments of this application, as long as the grating structure can satisfy at least one of the above settings for the first included angle A1, the second included angle A2, the period d, the duty cycle, and the height h, the purpose of improving the diffraction efficiency of the grating structure can be achieved.

[0119] Optionally, such as Figure 7 , Figure 19 , Figure 20 and Figure 24 As shown, the grating structure 100 of this embodiment further includes a first film layer 30, which is disposed on the side of the blazed grating 20 away from the substrate 10. The first film layer 30 includes a plurality of first sub-film layers 31, which are disposed one-to-one with a plurality of grating sub-structures 21. The orthographic projection of the first sub-film layer 31 on the substrate 10 coincides with the orthographic projection of the grating sub-structure 21 on the substrate 10. The refractive index of the first sub-film layer 31 is greater than or equal to the refractive index of the grating sub-structure 21. The first sub-film layer 31 has a first height along the direction perpendicular to the substrate 10.

[0120] In this embodiment, the first film layer 30 is a high refractive index film layer disposed on the side of the blazed grating 20 away from the substrate 10; by this arrangement, the grating structure can have higher diffraction efficiency without affecting the refractive index of the original grating structure.

[0121] Optionally, in this embodiment of the application, the first height is greater than or equal to 10 nm and less than or equal to 100 nm.

[0122] When the first height is less than 10 nm, the improvement degree of the diffraction efficiency of the grating structure by setting the first film layer 30 is reduced; when the first height is greater than 100 nm, the processing difficulty and production cost are increased, and the improvement degree of the diffraction efficiency of the grating structure is limited.

[0123] In the embodiment of the present application, the first height is greater than or equal to 10 nm and less than or equal to 100 nm, which not only effectively improves the diffraction efficiency of the grating structure and increases the utilization rate of light, but also is easy to manufacture, and has low processing difficulty and production cost.

[0124] Optionally, as shown in Figure 7 , Figure 19 , Figure 20 and Figure 24 , in the embodiment of the present application, the first sub-film layer 31 covers the top wall 23, the first side wall 24 and the second side wall 25 of the grating sub-structure 21, that is, covers the "upper base" and "waist" of the "ladder-shaped" grating sub-structure 21.

[0125] Specifically, as shown in Figure 6 and Figure 7 , in the embodiment of the present application, the material of the grating sub-structure 21 is an optical resin material, and optionally, the refractive index of the optical resin material is greater than or equal to 1.1 and less than or equal to 2.0, the period d of the blazed grating 20 is greater than or equal to 300 nm and less than or equal to 700 nm, the duty cycle of the blazed grating 20 is greater than or equal to 0.2 and less than or equal to 0.9, the height (which can be specifically the height h of the grating sub-structure 21) of the blazed grating 20 is greater than or equal to 220 nm and less than or equal to 580 nm, the first included angle A1 is greater than or equal to 45° and less than or equal to 90°, and the second included angle A2 is greater than or equal to 10° and less than or equal to 50°. The first film layer 30 is a high-refractive-index film layer, the material of the first sub-film layer 31 is titanium dioxide (TiO2), and optionally, the refractive index of the first sub-film layer 31 is greater than or equal to 2.0 and less than or equal to 4.0, and the first height is greater than or equal to 10 nm and less than or equal to 100 nm.

[0126] In the embodiment of the present application, the period, duty cycle, grating sub-structure material selection, height, grating inclination angle (including the first included angle A1 and the second included angle A2) of the blazed grating 20, whether to be coated (for example, not coated in Figure 6 , and coated with the first film layer 30 in Figure 7 ), and the optimization and design of the refractive index, height and other parameters of the first sub-film layer are optimized and designed, so as to obtain a new type of diffraction grating with high ±1 order diffraction efficiency, so that the grating structure has higher diffraction efficiency.

[0127] As shown in Figure 25 and Figure 28 , Figure 25The diagram shows a top view of a waveguide structure according to an embodiment of this application. After passing through the coupling grating, the ±1st order light can pass through the deflection grating and enter the output grating respectively, thus achieving full utilization of the light. Figure 28 The simulation curve of the diffraction efficiency of the grating structure in Embodiment 1 of this application is shown. Figure 28 Curve a in the diagram represents the relationship between diffraction angle and diffraction efficiency for the grating structure at -1st order diffraction; curve b represents the relationship between diffraction angle and diffraction efficiency for the grating structure at 0th order diffraction; and curve c represents the relationship between diffraction angle and diffraction efficiency for the grating structure at +1st order diffraction. Figure 28 The simulation curve of the diffraction efficiency shows that the +1st order ( Figure 28 The average diffraction efficiency of the c-curve (within FOV ±16°) is 30% (which can be verified by...). Figure 28 The average diffraction efficiency of the +1st order is obtained by averaging the diffraction efficiency, and the -1st order ( Figure 28 The average diffraction efficiency of the a-curve in this application is 41% at an FOV of ±16°. Compared with related technologies using rectangular gratings, the diffraction efficiency of the grating structure in this application embodiment is improved by 3 times.

[0128] In another specific embodiment of this application (Example 2), as follows: Figure 20 As shown, the difference from the above embodiment (Example 1) is that the grating structure 100 further includes a second film layer 40, which is disposed on the side of the first film layer 30 away from the substrate 10. The second film layer 40 includes a plurality of second sub-film layers 41, which are disposed one-to-one with a plurality of grating sub-structures 21. The orthographic projection of the second sub-film layer 41 on the substrate 10 coincides with the orthographic projection of the grating sub-structure 21 on the substrate 10. The refractive index of the second sub-film layer 41 is less than that of the first sub-film layer 31. The second sub-film layer 41 has a second height along the direction perpendicular to the substrate 10.

[0129] In this embodiment, the second film layer 40 is a low-refractive-index film layer disposed on the side of the first film layer 30 away from the substrate 10; a plurality of second sub-film layers 41 are disposed in a one-to-one correspondence with a plurality of grating sub-structures 21, and the orthographic projection of the second sub-film layer 41 on the substrate 10 coincides with the orthographic projection of the grating sub-structure 21 on the substrate 10. Along the direction perpendicular to the substrate 10, the second sub-film layer 41 has a second height. Through this arrangement, the grating structure can have a higher diffraction efficiency.

[0130] Optionally, in this embodiment of the application, the second height is greater than or equal to 50 nm and less than or equal to 100 nm.

[0131] When the second height is less than 50 nm, the improvement degree of the diffraction efficiency of the grating structure by setting the second film layer 40 is reduced; when the second height is greater than 100 nm, the processing difficulty and production cost are increased, and the improvement degree of the diffraction efficiency of the grating structure is limited.

[0132] In the embodiment of the present application, the second height is greater than or equal to 50 nm and less than or equal to 100 nm, which not only effectively improves the diffraction efficiency of the grating structure and increases the utilization rate of light, but also is easy to manufacture, and has low processing difficulty and production cost.

[0133] Specifically, as shown in Figure 20 In the embodiment of the present application, the material of the grating substructure 21 is an optical resin material, and the refractive index of the optical resin material is greater than or equal to 1.1 and less than or equal to 2.0. The period d of the blazed grating 20 is greater than or equal to 300 nm and less than or equal to 700 nm. The duty cycle of the blazed grating 20 is greater than or equal to 0.2 and less than or equal to 0.9. The height of the blazed grating 20 (which can be specifically the height h of the grating substructure 21) is greater than or equal to 220 nm and less than or equal to 580 nm. The first included angle A1 is greater than or equal to 45° and less than or equal to 90°. The second included angle A2 is greater than or equal to 10° and less than or equal to 50°. The first film layer 30 is a high-refractive-index film layer. The material of the first sub-film layer 31 is titanium dioxide (TiO2), and the refractive index is greater than or equal to 2.0 and less than or equal to 4.0. The first height is greater than or equal to 10 nm and less than or equal to 100 nm. The second film layer 40 is a low-refractive-index film layer. The material of the second sub-film layer 41 is an optical resin material. The refractive index of the second sub-film layer 41 is greater than or equal to 1.1 and less than or equal to 1.5. The second height is greater than or equal to 50 nm and less than or equal to 100 nm.

[0134] In the embodiment of the present application, the period, duty cycle, grating substructure material, height, grating included angle (including the first included angle A1 and the second included angle A2), whether to be coated, the refractive index and height of the first sub-film layer, the refractive index and height of the second sub-film layer, and other parameters of the blazed grating 20 are optimized and designed, so that a new type of diffraction grating with high ±1 order diffraction efficiency is obtained, and the grating structure has higher diffraction efficiency.

[0135] As shown in Figure 25 and Figure 29 As shown in Figure 25 The top view of the waveguide structure of the embodiment of the present application is shown. After the light passes through the in-coupling grating, ±1 order light can enter the out-coupling grating through the turning grating respectively, so that the light is fully utilized; Figure 29 The simulation curve of the diffraction efficiency of the grating structure of the second embodiment of the present application is shown Figure 29The curve a is a corresponding relationship curve of the diffraction angle and the diffraction efficiency when the grating structure is in-1 order diffraction, the curve b is a corresponding relationship curve of the diffraction angle and the diffraction efficiency when the grating structure is in 0 order diffraction, and the curve c is a corresponding relationship curve of the diffraction angle and the diffraction efficiency when the grating structure is in +1 order diffraction, and the diffraction efficiency of the grating structure is simulated by Figure 29 The simulation curve diagram of the diffraction efficiency of the grating structure shows that the average value of the +1 order diffraction efficiency is 27% when the FOV is ± 16°, and the average value of the-1 order diffraction efficiency is 44% when the FOV is ± 16°. Compared with the related art adopting the rectangular grating, the diffraction efficiency of the grating structure of the embodiment of the present application is improved by 3 times.

[0136] In another specific embodiment (Embodiment Three) of the present application, as shown in Figure 23 and Figure 24 The difference from the above specific embodiment (Embodiment One) is that the first side wall 24 includes a first wall segment 26 and a third wall segment 28, one end of the first wall segment 26 is connected with the top wall 23, and the other end of the first wall segment 26 away from the top wall 23 is connected with the bottom wall 22 through the third wall segment 28; the first wall segment 26 has a first included angle A1 with the preset plane, and the first included angle A1 is a right angle or an acute angle; in the cross section perpendicular to the substrate 10, the cross-sectional shape of the first wall segment 26 is linear, curved or bent; and the third wall segment 28 is perpendicular to the substrate 10.

[0137] Optionally, as shown in Figure 23 and Figure 24 In the embodiment of the present application, the second side wall 25 includes a second wall segment 27 and a fourth wall segment 29, one end of the second wall segment 27 is connected with the top wall 23, and the other end of the second wall segment 27 away from the top wall 23 is connected with the bottom wall 22 through the fourth wall segment 29; the second wall segment 27 has a second included angle A2 with the preset plane, and the second included angle A2 is an acute angle; in the cross section perpendicular to the substrate 10, the cross-sectional shape of the second wall segment 27 is linear, curved or bent; and the fourth wall segment 29 is perpendicular to the substrate 10.

[0138] Through this arrangement, not only can the light energy be more efficiently shifted and concentrated to the required diffraction order, achieving the purpose of optimizing the diffraction efficiency of the blazed grating 20 and increasing the utilization rate of light, but also better brightness uniformity can be achieved under the existing field of view angle.

[0139] Optionally, as shown in Figure 23 and Figure 24 In the embodiment of the present application, in the cross section perpendicular to the substrate 10, the cross-sectional shape of the grating substructure 21 is a trapezoidal upper part and a rectangular lower part, and the upper trapezoidal part is stacked on the lower rectangular part. Optionally, as shown in Figure 24As shown, in the embodiment of the present application, the first sub-film layer 31 covers the top wall 23, the first wall segment 26 and the second wall segment 27 of the grating sub-structure 21, that is, covers the "upper base" and "waist" of the "ladder-shaped" part of the upper portion of the grating sub-structure 21.

[0140] Optionally, in the embodiment of the present application, the first sub-film layer 31 of the first film layer 30 has a first height in the direction perpendicular to the substrate 10; the first height is greater than or equal to 50 nm and less than or equal to 100 nm.

[0141] When the first height is less than 50 nm, the degree of improvement of the diffraction efficiency of the grating structure by setting the first film layer 30 is reduced; when the first height is greater than 100 nm, the processing difficulty and production cost are increased, and the degree of improvement of the diffraction efficiency of the grating structure is limited.

[0142] In the embodiment of the present application, the first height is set to be greater than or equal to 50 nm and less than or equal to 100 nm, which not only can effectively improve the diffraction efficiency of the grating structure and increase the utilization rate of light, but also is easy to manufacture and has low processing difficulty and production cost.

[0143] Specifically, as shown in Figure 23 and Figure 24 In the embodiment of the present application, the material of the grating sub-structure 21 is an optical resin material, and optionally, the refractive index of the optical resin material is greater than or equal to 1.1 and less than or equal to 2.0, the period d of the blazed grating 20 is greater than or equal to 300 nm and less than or equal to 700 nm, the duty cycle of the blazed grating 20 is greater than or equal to 0.2 and less than or equal to 0.9, the height of the blazed grating 20 (which can be specifically the height h of the grating sub-structure 21) is greater than or equal to 220 nm and less than or equal to 580 nm, the first included angle A1 is greater than or equal to 45° and less than or equal to 90°, and the second included angle A2 is greater than or equal to 10° and less than or equal to 50°. The first film layer 30 is a high-refractive-index film layer, and the material of the first sub-film layer 31 is titanium dioxide (TiO2), and optionally, the refractive index of the first sub-film layer 31 is greater than or equal to 2.0 and less than or equal to 4.0, and the first height is greater than or equal to 50 nm and less than or equal to 100 nm.

[0144] In the embodiment of the present application, the period, duty cycle, material of the grating sub-structure, height, grating included angle (including the first included angle A1 and the second included angle A2) of the blazed grating 20, whether to be coated, and the optimization and design of the refractive index and height of the first sub-film layer are optimized and designed, so that a new type of diffraction grating with high ±1 order diffraction efficiency is obtained, and the grating structure has higher diffraction efficiency.

[0145] As shown in Figure 25 and Figure 30 , Figure 25A top view of the waveguide structure of the embodiment of the present application is shown. After passing through the in-coupling grating 220, the ±1 order light can enter the out-coupling grating 230 through the turning grating 240, so as to realize full utilization of light; Figure 30 A simulation curve diagram of the diffraction efficiency of the grating structure of the third embodiment of the present application is shown. Figure 30 The a curve is the corresponding relationship curve of the diffraction angle and the diffraction efficiency of the grating structure at the-1 order diffraction, the b curve is the corresponding relationship curve of the diffraction angle and the diffraction efficiency of the grating structure at the 0 order diffraction, and the c is the corresponding relationship curve of the diffraction angle and the diffraction efficiency of the grating structure at the +1 order diffraction. Through the simulation curve diagram of the diffraction efficiency of the grating structure, it can be known that the average of the +1 order diffraction efficiency under the FOV of ±16° is 41%, and the average of the-1 order diffraction efficiency under the FOV of ±16° is 36%. Compared with the related art adopting the rectangular grating, the diffraction efficiency of the grating structure of the present application is improved by 4 times. Figure 30

[0146] Of course, in an optional embodiment of the present application, the grating structure 100 can also include a second film layer 40 according to actual needs. The structure and arrangement of the second film layer 40 are similar to those of the second film layer 40 in the above embodiment (embodiment two), which will not be described here.

[0147] The technical scheme of the present application mainly aims at the problems of low diffraction efficiency and poor brightness uniformity in the application of the existing rectangular grating, and a new type of diffraction grating structure is designed and proposed. The design mainly aims at the grating structure to improve the diffraction efficiency and brightness uniformity of the grating. Optionally, the diffraction grating structure can be a diffraction nanometer grating structure.

[0148] Specifically, the grating height, period, duty cycle, material, flash grating angle, whether to be coated, film layer height and other parameters of the grating structure are designed to obtain a blazed grating, instead of a traditional rectangular grating, to achieve the purpose of optimizing the diffraction efficiency and brightness uniformity of the grating and increasing the utilization rate of light. The grating structure has excellent brightness uniformity and high diffraction efficiency, not only maintains the FOV value of the rectangular grating, but also greatly improves the diffraction efficiency, which is improved by about 4 times compared with the rectangular grating.

[0149] Based on the same inventive concept, the present application provides a preparation method of a grating structure. The flowchart of the method is shown in Figure 3 The method comprises the following steps.

[0150] S101, providing a substrate 10;

[0151] ​S102, a blazed grating 20 is made on one side of the substrate 10, the blazed grating 20 includes a plurality of grating substructures 21, the plurality of grating substructures 21 are sequentially and spaced apart along a direction parallel to the substrate 10; by setting parameters of the blazed grating 20, diffraction efficiency of the blazed grating 20 is at most improved by 4 times; wherein the parameters of the blazed grating 20 include at least one of a period d, a duty cycle, a material of the grating substructure 21, a height h, and an inclination angle.

[0152] In the embodiment of the present application, the substrate 10 has a supporting effect on the blazed grating 20. The plurality of grating substructures 21 of the blazed grating 20 are sequentially and spaced apart along a direction parallel to the substrate 10, by setting the parameters (including at least one of the period d, the duty cycle, the material of the grating substructure 21, the height h, and the inclination angle) of the blazed grating 20, most of the light energy of the blazed grating 20 is concentrated in a preset direction, i.e. concentrated in a certain preset spectral level, thereby realizing control of the light direction, and the intensity of the spectrum in the preset direction is the maximum. By setting the parameters of the blazed grating 20, the embodiment of the present application can achieve the purpose of optimizing the diffraction efficiency and the brightness uniformity of the blazed grating 20, and increase the utilization rate of light. Compared with the traditional grating, the first-order diffraction efficiency of the blazed grating 20 of the embodiment of the present application can be at most improved by 4 times.

[0153] Optionally, as shown in Figure 7 , Figure 19 , Figure 20 and Figure 24 , in an optional embodiment of the present application, the method for preparing the grating structure further includes:

[0154] A first film layer 30 is made on a side of the blazed grating 20 away from the substrate 10, the first film layer 30 includes a plurality of first sub-film layers 31, the plurality of first sub-film layers 31 are arranged one-to-one with the plurality of grating substructures 21, the first sub-film layer 31 is in a position of a normal projection on the substrate 10, and the normal projection of the grating substructure 21 on the substrate 10 is overlapped; the refractive index of the first sub-film layer 31 is greater than or equal to the refractive index of the grating substructure 21.

[0155] In a specific embodiment of the present application, as shown in Figures 4 to 7As shown, firstly, an optical resin film 51 is deposited on a substrate 10 (optionally, the material of the substrate 10 is glass) by spin coating or other methods; and optionally, a blazed grating 20 is prepared by electron beam gradient etching and development using EBL (Electron Beam Lithography). Optionally, the grating period d of the prepared blazed grating is greater than or equal to 300 nm and less than or equal to 700 nm, the grating duty cycle is greater than or equal to 0.2 and less than or equal to 0.9, the grating height h is greater than or equal to 220 nm and less than or equal to 580 nm, and the grating tilt angles are first angle A1 greater than or equal to 45° and less than or equal to 90°, and second angle A2 greater than or equal to 10° and less than or equal to 50°; then, optionally, the blazed grating is further processed by PECVD (Plasma Enhanced Chemical Dioxide). A high-refractive-index film layer, optionally made of TiO2, is deposited on the surface of the blazed grating 20 away from the glass substrate by means of methods such as vapor deposition (plasma-enhanced chemical vapor deposition) to form a first film layer 30. Optionally, the refractive index of the first film layer 30 is greater than or equal to 2.0 and less than or equal to 4.0, and the thickness of the first film layer 30 is greater than or equal to 10 nm and less than or equal to 100 nm. The grating structure formed corresponds to the grating structure of Embodiment 1 above.

[0156] pass Figure 28 The simulation curves of the diffraction efficiency show that the average diffraction efficiency of the +1st order is 30% at an FOV of ±16°, and the average diffraction efficiency of the -1st order is 41% at an FOV of ±16°. Compared with related technologies using rectangular gratings, the diffraction efficiency of the grating structure in this application embodiment is improved by 3 times.

[0157] In another specific embodiment of this application, such as Figures 8 to 19 As shown, firstly, a photoresist film layer 53 is optionally deposited on the first glass substrate 52 by spin coating or other methods, and a main template 54 is optionally prepared by EBL electron beam gradient etching and development. The structure and shape of the main template 54 are the same as those of the blazed grating 20 to be prepared in this application. Then, nanoimprinting is used to transfer the shape of the main template 54 to a soft template 55 (the soft template 55 includes a third glass substrate 58 and a template adhesive layer 59 disposed on the third glass substrate 58) to form a master template 56. The master template 56 has a hollow pattern 57, which is complementary to or interlocked with the shape of the blazed grating 20 in this embodiment. Then, by... Figure 17According to the nano-imprinting process steps, a layer of optical resin film 51 is deposited on the second glass substrate (i.e. substrate 10) by spin coating or the like, and the refractive index of the optical resin material is greater than or equal to 1.1 and less than or equal to 2.0. Then, the second glass substrate with the layer of optical resin film 51 is pressed against the master template 56 by nano-imprinting, so that the optical resin film 51 has a shape complementary to or interfitting with the hollow pattern 57 of the master template 56, to prepare the blazed grating 20.

[0158] The grating period d of the prepared blazed grating 20 is greater than or equal to 300 nm and less than or equal to 700 nm, the grating duty cycle is greater than or equal to 0.2 and less than or equal to 0.9, the grating height h is greater than or equal to 220 nm and less than or equal to 580 nm, the first included angle A1 of the grating inclination is greater than or equal to 45° and less than or equal to 90°, and the second included angle A2 is greater than or equal to 10° and less than or equal to 50°. Then, a layer of high-refractive-index film layer with an optional material of TiO2 or the like is deposited on the surface of the prepared blazed grating 20 away from the second glass substrate by PECVD or the like, to form the first film layer 30. The refractive index of the first film layer 30 is greater than or equal to 2.0 and less than or equal to 4.0, and the thickness of the first film layer 30 is greater than or equal to 10 nm and less than or equal to 100 nm. The grating structure formed corresponds to the grating structure of the above-mentioned embodiment one.

[0159] According to the simulation curve of the diffraction efficiency of the blazed grating structure of the embodiment of the application, Figure 28 The average of the +1 order diffraction efficiency is 30% when the FOV is ±16°, and the average of the -1 order diffraction efficiency is 41% when the FOV is ±16°. Compared with the related art using a rectangular grating, the diffraction efficiency of the grating structure of the embodiment of the application is improved by 3 times. The preparation process can achieve the purposes of rapidity, high efficiency and large-area integration, and has great significance for realizing mass production process.

[0160] In another specific embodiment of the application, as Figures 21 to 24As shown, firstly, an optical resin film layer 51 is deposited on a substrate 10 (optionally, the substrate 10 is a glass substrate, and optionally, the material of the glass substrate is white glass) by spin coating or other methods. Optionally, the refractive index of the optical resin material is greater than or equal to 1.1 and less than or equal to 2.0. Then, optionally, a blazed grating 20 is prepared by EBL exposure etching and development. Optionally, the grating period of the prepared blazed grating is greater than or equal to 300 nm and less than or equal to 700 nm, the grating duty cycle is greater than or equal to 0.2 and less than or equal to 0.9, and the grating height is greater than or equal to 220 nm and less than or equal to 700 nm. The first included angle A1 of the grating is greater than or equal to 45° and less than or equal to 90°, and the second included angle A2 is greater than or equal to 10° and less than or equal to 50°. Optionally, a high refractive index film layer, preferably made of TiO2, is deposited on the surface of the blazed grating away from the glass substrate by means of PECVD or the like to form a first film layer 30. Optionally, the refractive index of the first film layer 30 is greater than or equal to 2.0 and less than or equal to 4.0, and the thickness of the first film layer 30 is greater than or equal to 50 nm and less than or equal to 100 nm. The grating structure formed corresponds to the grating structure of Embodiment 3 above.

[0161] pass Figure 30 The simulation curves of the diffraction efficiency show that the average diffraction efficiency of the +1st order is 41% at an FOV of ±16°, and the average diffraction efficiency of the -1st order is 36% at an FOV of ±16°. Compared with related technologies using rectangular gratings, the diffraction efficiency of the grating structure in this application embodiment is improved by 4 times.

[0162] Optionally, such as Figures 4 to 7 as well as Figure 20 As shown, in one optional embodiment of this application, the method for fabricating the grating structure further includes:

[0163] A first film layer 30 is formed on the side of the blazed grating 20 away from the substrate 10. The first film layer 30 includes a plurality of first sub-film layers 31. The plurality of first sub-film layers 31 are arranged in a one-to-one correspondence with a plurality of grating substructures 21. The orthographic projection of the first sub-film layer 31 on the substrate 10 coincides with the orthographic projection of the grating substructure 21 on the substrate 10. The refractive index of the first sub-film layer 31 is greater than or equal to the refractive index of the grating substructure 21.

[0164] A second film layer 40 is formed on the side of the first film layer 30 away from the substrate 10. The second film layer 40 includes a plurality of second sub-film layers 41. The plurality of second sub-film layers 41 are arranged in a one-to-one correspondence with a plurality of grating sub-structures 21. The orthographic projection of the second sub-film layer 41 on the substrate 10 coincides with the orthographic projection of the grating sub-structure 21 on the substrate 10. The refractive index of the second sub-film layer 41 is less than or equal to the refractive index of the first sub-film layer 31.

[0165] In another specific embodiment of the present application, as shown in Figures 4 to 7 and Figure 20 first, a film layer of optical resin material is deposited on the glass substrate, optionally by spin coating or the like; and a blazed grating is prepared by EBL electron beam gradient exposure etching and development, optionally, the prepared blazed grating has a grating period greater than or equal to 300 nm and less than or equal to 700 nm, a grating duty cycle greater than or equal to 0.2 and less than or equal to 0.9, a grating height greater than or equal to 220 nm and less than or equal to 580 nm, a first included angle A1 of the grating inclination greater than or equal to 45° and less than or equal to 90°, and a second included angle A2 greater than or equal to 10° and less than or equal to 50°; then a high refractive index film layer, optionally of TiO2 or the like, is deposited on the surface of the blazed grating away from the glass substrate by PECVD or the like to form a first film layer, optionally, the refractive index of the first film layer is greater than or equal to 2.0 and less than or equal to 4.0, and the film layer thickness is greater than or equal to 10 nm and less than or equal to 100 nm; then, a low refractive index optical resin material is deposited on the surface of the first film layer away from the glass substrate by PECVD or the like to form a second film layer, optionally, the refractive index of the optical resin material is greater than or equal to 1.1 and less than or equal to 1.5, and the second film layer thickness is greater than or equal to 50 nm and less than or equal to 100 nm; the grating structure formed corresponds to the grating structure of Embodiment Two described above.

[0166] From the simulation curve of the diffraction efficiency of Figure 29 , it can be seen that the average of the +1 order diffraction efficiency under FOV of ±16° is 27%, and the average of the -1 order diffraction efficiency under FOV of ±16° is 44%, compared with the related art using a rectangular grating, the diffraction efficiency of the grating structure of the present application is improved by 3 times.

[0167] The present application not only provides a design method of a grating structure, mainly aiming at the design of a grating structure to achieve the purpose of improving the diffraction efficiency and brightness uniformity of the grating, but also provides a preparation method of the grating structure, and the preparation process of the grating structure has the advantages of simple preparation process and easy integration, and is expected to be used in the field of AR / VR display.

[0168] Based on the same inventive concept, the present application provides a waveguide structure, and a structure frame diagram of the waveguide structure 200 is as shown in Figures 25 to 27As shown, the waveguide structure includes a waveguide medium layer 210 having a first region and a second region; further includes: a coupling-in grating 220, a coupling-out grating 230 and a turning grating 240, the waveguide medium layer 210 further has a third region; wherein: the normal projection of the coupling-in grating 220 on the waveguide medium layer 210 is located in the first region; the normal projection of the coupling-out grating 230 on the waveguide medium layer 210 is located in the second region; and the normal projection of the turning grating 240 on the waveguide medium layer 210 is located in the third region. At least one of the coupling-in grating 220, the coupling-out grating 230 and the turning grating 240 adopts the grating structure as described above.

[0169] In the embodiments of the present application, the coupling-in grating 220, the coupling-out grating 230 and the turning grating 240 are all arranged on the waveguide medium layer 210, and the waveguide medium layer 210 supports the coupling-in grating 220, the coupling-out grating 230 and the turning grating 240. The coupling-in grating 220 is used to change the propagation direction of light so as to make the light enter the waveguide medium layer 210, the turning grating 240 is used to change the propagation direction of light so as to facilitate the propagation of light to the coupling-out grating 230, and the coupling-out grating 230 is used to change the propagation direction of light so as to make the light exit from the waveguide medium layer 210.

[0170] In the embodiments of the present application, the first region, the second region and the third region are arranged separately or at most partially overlap; the normal projection of the coupling-in grating 220 on the waveguide medium layer 210, the normal projection of the coupling-out grating 230 on the waveguide medium layer 210 and the normal projection of the turning grating 240 on the waveguide medium layer 210 are arranged separately or at most partially overlap. It should be noted that the structure of the waveguide structure of the embodiments of the present application and the propagation principle of light in the waveguide structure are similar to the prior art (such as the display system based on the surface relief grating diffraction waveguide scheme and the basic principle described above), and will not be described here.

[0171] In the embodiments of the present application, since at least one of the coupling-in grating 220, the coupling-out grating 230 and the turning grating 240 of the waveguide structure adopts the grating structure of the embodiments of the present application, the waveguide structure of the embodiments of the present application also has the above beneficial effects of the grating structure of the embodiments of the present application, and will not be described here.

[0172] In the embodiments of the present application, at least one of the coupling-in grating 220, the coupling-out grating 230 and the turning grating 240 of the waveguide structure adopts the grating structure as described above, and by optimizing the waveguide structure, designing appropriate coupling-in grating, coupling-out grating and turning grating, the utilization of ±1 order light is realized, and the diffraction efficiency is improved by nearly 4 times compared with the rectangular grating.

[0173] It should be noted that the grating structure in this application embodiment can not only serve as a coupling grating, possessing advantages such as high coupling diffraction efficiency and ease of fabrication and integration, but also as a coupling grating (for example, used in AR glasses as a coupling grating), exhibiting good FOV uniformity to achieve brightness uniformity in the coupling region. Of course, in some optional embodiments of this application, such as... Figure 26 and Figure 27 As shown, the coupling grating 230 can be a two-dimensional grating (such as...). Figure 26 As shown, the coupling grating 230 is a cylindrical grating; optionally, the coupling grating 230 is a circular grating. Figure 27 As shown, the coupling grating 230 adopts a diamond-shaped grating to increase the FOV effect.

[0174] Specifically, the waveguide structure can be an augmented reality optical waveguide sheet.

[0175] This application embodiment achieves higher diffraction efficiency by optimizing the design of the grating structure. Furthermore, it optimizes the design of the grating structure of the waveguide structure (such as the coupling grating, the folding grating, and the coupling grating) to achieve higher diffraction efficiency and better brightness uniformity.

[0176] In one optional embodiment of this application, the waveguide structure may include an input grating 220 and an output grating 230, but exclude the folding grating 240, depending on actual needs. The waveguide dielectric layer 210 may have a first region and a second region, but not a third region. Other structures and configurations in this embodiment, except for the folding grating 240 and the third region, may be the same as or similar to the waveguide structure in the above embodiments, and will not be described in detail here.

[0177] Based on the same inventive concept, this application provides a display panel, the structural framework of which is shown in the schematic diagram below. Figure 31 As shown ( Figure 31 The middle arrow indicates the direction of light propagation, including the substrate, and

[0178] The grating structure 100 described above is disposed on one side of the substrate; or the waveguide structure 200 described above is disposed on one side of the substrate.

[0179] In this embodiment, the display panel includes a grating structure 100 or a waveguide structure 200, which is mounted on one side of a substrate, and the substrate provides support for the grating structure 100 or the waveguide structure 200.

[0180] Optionally, such as Figure 31As shown, in the embodiment of the present application, the display panel includes a waveguide medium layer 210, a coupling-in grating 220, a coupling-out grating 230, and a light emitting device or a light propagating device 250. The coupling-in grating 220 and the coupling-out grating 230 are both arranged on the waveguide medium layer 210. The coupling-in grating 220 adopts the grating structure 100 of the embodiment of the present application, and the coupling-out grating 230 adopts a conventional grating structure (optionally, such as Figure 31 As shown, the coupling-out grating 230 adopts a rectangular grating; of course, in another alternative embodiment, the coupling-out grating 230 can also adopt the grating structure 100 of the embodiment of the present application). The light emitting device can emit light, and the light propagating device can propagate light. Optionally, the light emitting device can be a micro display, and the light propagating device can be a collimating ocular group, which can not only propagate light but also convert light into collimated light. It should be noted that the basic principle of the display panel in the embodiment of the present application is similar to that of the prior art (such as the basic principle of the display system based on the surface relief grating diffractive light waveguide scheme described above), which will not be described here. Figure 1

[0181] Specifically, the display panel can be a diffractive light waveguide AR system, or any one of an LCD (Liquid Crystal Display) display panel, an OLED (Organic Light Emitting Diode) display panel, a Micro LED (Micro Light Emitting Diode) display panel, and a Mini LED (Mini Light Emitting Diode) display panel.

[0182] It should be noted that since the display panel of the embodiment of the present application includes the grating structure or the waveguide structure of the embodiment of the present application, the display panel of the embodiment of the present application also has the above beneficial effects of the grating structure or the waveguide structure of the embodiment of the present application, which will not be described here.

[0183] Based on the same inventive concept, the embodiment of the present application provides a display device including the display panel described above.

[0184] Specifically, the display device can be an AR display device, such as AR glasses or an AR head-mounted device (for example, an AR helmet), etc.; or a light waveguide display device or other display device (for example, a spectrometer).

[0185] It should be noted that since the display device of the embodiment of the present application includes the display panel of the embodiment of the present application, the display device of the embodiment of the present application also has the above beneficial effects of the display panel of the embodiment of the present application, which will not be described here.

[0186] ​The application can achieve the following beneficial effects:

[0187] In the embodiments of the application, the plurality of grating substructures of the blazed grating are sequentially and spacedly arranged along a direction parallel to the substrate. By setting parameters (including at least one of period, duty cycle, material, height, and inclination angle of the grating substructure) of the blazed grating, most of the light energy of the blazed grating is concentrated in a preset direction, i.e., concentrated in a certain preset spectral level, thereby achieving control of the light direction, and the intensity of the spectrum is the largest in the preset direction. The embodiments of the application can achieve the purpose of optimizing the diffraction efficiency and brightness uniformity of the blazed grating by setting the parameters of the blazed grating, increase the utilization rate of light, and enable the first-order diffraction efficiency of the blazed grating to be at most increased by 4 times.

[0188] Those skilled in the art can understand that the steps, measures, and schemes in the various operations, methods, and processes discussed in the application can be alternated, changed, combined, or deleted. Further, other steps, measures, and schemes in the various operations, methods, and processes discussed in the application can also be alternated, changed, rearranged, decomposed, combined, or deleted. Further, the steps, measures, and schemes in the various operations, methods, and processes in the prior art can also be alternated, changed, rearranged, decomposed, combined, or deleted.

[0189] In the description of the application, the directions or positional relationships indicated by the words "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are exemplary directions or positional relationships shown based on the drawings, and are for the convenience of description or simplification of the description of the embodiments of the application, and do not indicate or imply that the devices or components indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0190] The terms "first", "second", are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the application, unless otherwise specified, the meaning of "plurality" is two or more.

[0191] In the description of the application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be directly connected, or indirectly connected through an intermediate medium; can be the communication inside two elements. Those skilled in the art can understand the specific meaning of the above terms in the application according to the specific circumstances.

[0192] In the description of the specification, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0193] It should be understood that, although each step in the flowchart of the accompanying drawings is displayed in sequence according to the indication of the arrow, the implementation order of the steps is not limited to the order indicated by the arrow. Unless otherwise specified herein, the steps in some implementation scenarios of the embodiments of the present application can be executed in other orders as required. Moreover, part or all of the steps in each flowchart can include multiple sub-steps or multiple stages based on the actual implementation scenario. Part or all of these sub-steps or stages can be executed at the same time or at different times. In the scenario where the execution time is different, the execution order of these sub-steps or stages can be flexibly configured according to the requirement, and the embodiments of the present application do not limit this.

[0194] The above only describes some embodiments of the present application. It should be pointed out that, for those skilled in the art, other similar implementation means based on the technical concept of the present application can be used without departing from the technical concept of the present application, and such implementation means also belong to the protection scope of the embodiments of the present application.

Claims

1. A grating structure, characterized by, The application relates to a substrate and a blazed grating arranged on one side of the substrate, wherein the blazed grating comprises a plurality of grating substructures arranged in sequence and at intervals along a direction parallel to the substrate. The blazed grating is set by parameters, so that the first-order diffraction efficiency of the blazed grating is at most increased by 4 times. The parameters of the blazed grating include at least one of a period, a duty cycle, a material of the grating substructure, a height, and an inclination angle. The grating substructure has a bottom wall facing the substrate, a top wall facing away from the substrate, a first side wall, and a second side wall, the bottom wall is connected to the top wall through the first side wall, and the top wall is connected to the bottom wall through the second side wall. The top wall is located in the projection of the bottom wall on the substrate. At least part of the first side wall is arranged at a right angle or an acute angle with a preset plane, and / or at least part of the second side wall is arranged at an acute angle with the preset plane, and the preset plane is parallel to the substrate. The first side wall comprises a first wall segment and a third wall segment, one end of the first wall segment is connected to the top wall, and the other end of the first wall segment away from the top wall is connected to the bottom wall through the third wall segment; the first wall segment has a first included angle with the preset plane, and the first included angle is a right angle or an acute angle; in a cross section perpendicular to the substrate, the cross section shape of the first wall segment is linear, curved, or bent; and the third wall segment is perpendicular to the substrate. The second side wall comprises a second wall segment and a fourth wall segment, one end of the second wall segment is connected to the top wall, and the other end of the second wall segment away from the top wall is connected to the bottom wall through the fourth wall segment; the second wall segment has a second included angle with the preset plane, and the second included angle is an acute angle; in a cross section perpendicular to the substrate, the cross section shape of the second wall segment is linear, curved, or bent; and the fourth wall segment is perpendicular to the substrate. The first included angle is greater than or equal to 45 degrees and less than or equal to 90 degrees. The second included angle is greater than or equal to 10 degrees and less than or equal to 50 degrees. The first film layer comprises a first sub-film layer, the first sub-film layer covers the top wall, the first wall segment, and the second wall segment of the grating substructure, the refractive index of the first sub-film layer is greater than or equal to the refractive index of the grating substructure, and the first sub-film layer has a first height in a direction perpendicular to the substrate, the first height is greater than or equal to 50 nm and less than or equal to 100 nm. The second film layer is arranged on the side of the first film layer away from the substrate, the second film layer comprises a plurality of second sub-film layers, the refractive index of the second sub-film layer is less than the refractive index of the first sub-film layer, and the second sub-film layer has a second height in a direction perpendicular to the substrate, the second height is greater than or equal to 50 nm and less than or equal to 100 nm. The first film layer is arranged on the side of the blazed grating away from the substrate. ​ 2. The grating structure of claim 1, wherein ​ The first film layer includes a plurality of first sub-film layers, the plurality of first sub-film layers are arranged one-to-one corresponding to the plurality of grating sub-structures, and a projection of the first sub-film layer on the substrate overlaps a projection of the grating sub-structure on the substrate.

3. The grating structure of claim 2, wherein, The plurality of second sub-film layers are arranged one-to-one corresponding to the plurality of grating sub-structures, and a projection of the second sub-film layer on the substrate overlaps a projection of the grating sub-structure on the substrate.

4. The grating structure of any one of claims 1 to 3, wherein, The period of the blazed grating is greater than or equal to 300 nm and less than or equal to 700 nm; or, The duty cycle of the blazed grating is greater than or equal to 0.2 and less than or equal to 0.9; or, The height of the grating sub-structure is greater than or equal to 220 nm and less than or equal to 580 nm along a direction perpendicular to the substrate.

5. A waveguide structure, characterized by The waveguide medium layer includes a first region and a second region; and further includes: The in-coupling grating and the out-coupling grating; or, The in-coupling grating, the out-coupling grating, and the turning grating, and the waveguide medium layer further includes a third region; Wherein: The projection of the in-coupling grating on the waveguide medium layer is located in the first region; The projection of the out-coupling grating on the waveguide medium layer is located in the second region; The projection of the turning grating on the waveguide medium layer is located in the third region; At least one of the in-coupling grating, the out-coupling grating, and the turning grating adopts the grating structure of any one of claims 1 to 4.

6. A display panel, characterized by, The substrate, and The grating structure of any one of claims 1 to 4 is arranged on one side of the substrate; or, The waveguide structure of claim 5 is arranged on one side of the substrate.

7. A display device, characterized by comprising: The display panel of claim 6.

8. A method of producing a grating structure as claimed in any one of claims 1-4, characterized in that The method includes: Providing a substrate; Manufacturing a blazed grating on one side of the substrate, the blazed grating including a plurality of grating sub-structures, and the plurality of grating sub-structures are arranged in sequence and spaced apart along a direction parallel to the substrate; By setting parameters of the blazed grating, a first-order diffraction efficiency of the blazed grating is at most improved by 4 times; The parameters of the blazed grating include at least one of a period, a duty cycle, a material of the grating sub-structure, a height, and an inclination angle.

9. The method of claim 8, wherein the method further comprises: Further including: Manufacturing a first film layer on a side of the blazed grating away from the substrate, the first film layer including a plurality of first sub-film layers, the plurality of first sub-film layers are arranged one-to-one corresponding to the plurality of grating sub-structures, a projection of the first sub-film layer on the substrate overlaps a projection of the grating sub-structure on the substrate, and a refractive index of the first sub-film layer is greater than or equal to a refractive index of the grating sub-structure; or, ​ A first film layer is made on a side of the blazed grating away from the substrate, the first film layer comprising a plurality of first sub-film layers, the plurality of first sub-film layers being arranged one-to-one corresponding to the plurality of grating sub-structures, a normal projection of the first sub-film layer on the substrate being coincident with a normal projection of the grating sub-structure on the substrate; a refractive index of the first sub-film layer being greater than or equal to a refractive index of the grating sub-structure; A second film layer is made on a side of the first film layer away from the substrate, the second film layer comprising a plurality of second sub-film layers, the plurality of second sub-film layers being arranged one-to-one corresponding to the plurality of grating sub-structures, a normal projection of the second sub-film layer on the substrate being coincident with a normal projection of the grating sub-structure on the substrate; a refractive index of the second sub-film layer being less than or equal to a refractive index of the first sub-film layer.

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