Grating structure and preparation method thereof, display device

Abstract

A grating structure, a preparation method thereof, and a display device. The preparation method of the grating structure comprises: forming a plurality of first protruding structures (2) arranged along a first direction (X) (S101); forming a first adhesive material (3) covering the plurality of first protruding structures (2), and forming a grating structure comprising a plurality of second protruding structures (7) by using the protruding structures comprising the first protruding structures (2) and the first adhesive material (3) (S102); wherein the surface of the first adhesive material (3) away from the first protruding structures (2) is a flat surface, the protruding structures comprising the first protruding structures (2) and the first adhesive material (3) correspond one-to-one to the second protruding structures (7), the shape of the second protruding structures (7) in the cross section along the first direction (X) is a triangle, and the second protruding structures (7) have at least one inclined flat surface.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to grating structures and their fabrication methods, and display devices. Background Technology

[0002] Augmented Reality (AR) glasses are predicted to become humanity's "third screen," possessing a very broad development prospect. Surface relief grating (SRG) diffractive waveguide solutions are considered the most promising mainstream AR waveguide lens fabrication solution due to their ease of mass production and excellent performance. Two-dimensional gratings for SRG AR waveguide sheets mainly include rectangular gratings, tilted gratings, and blazed gratings. Blazed gratings have attracted widespread attention due to their excellent diffraction efficiency.

[0003] Currently, the main methods for preparing blazed grating templates include diamond machining, wet etching, and electron beam writing. Diamond machining is limited by the size of the cutting tools, and the tools are prone to wear during the machining process, affecting the machining accuracy. Wet etching for preparing blazed gratings is limited by the crystal orientation of the material, making it impossible to flexibly select the grating angle. Electron beam writing requires the use of gradient exposure technology, and the grating's bevel is wavy, affecting waveguide efficiency. Summary of the Invention

[0004] This disclosure provides a method for fabricating a grating structure, the method comprising:

[0005] Multiple first protrusion structures are formed along a first direction;

[0006] A first adhesive material is formed to cover at least a plurality of first protrusion structures, and a grating structure including a plurality of second protrusion structures is formed using the protrusion structures including the first protrusion structures and the first adhesive material; wherein, the surface of the first adhesive material facing away from the first protrusion structures is a flat surface; the protrusion structures including the first protrusion structures and the first adhesive material correspond one-to-one with the second protrusion structures, the shape of the cross section of the second protrusion structure along the first direction is triangular, and the second protrusion structure has at least one inclined flat surface.

[0007] In some embodiments, a plurality of first protrusion structures arranged along a first direction are formed, including:

[0008] A first substrate is provided, and a plurality of first protrusion structures arranged along a first direction are formed on the first substrate;

[0009] Forming a first adhesive material that covers at least a plurality of first protrusion structures and using the protrusion structures including the first protrusion structures and the first adhesive material to form a grating structure including a plurality of second protrusion structures, including:

[0010] A first adhesive material is formed to cover the first protruding structure, and the first adhesive material is cured to form a plurality of protruding structures including the first protruding structure and the first adhesive material, thereby obtaining a first template; wherein, the shape of the cross section of the protruding structure along the first direction is triangular, and the protruding structure has at least one inclined flat surface;

[0011] A second adhesive material is provided, and a first template is used as an imprinting template. An imprinting process is used to form a second protrusion structure that corresponds one-to-one with the protrusion structure. The second protrusion structure is then transferred onto a second substrate to obtain a grating structure.

[0012] In some embodiments, using a first template as an imprinting template and employing an imprinting process to form a second protruding structure in the second adhesive material that corresponds one-to-one with the protruding structure includes:

[0013] A template adhesive is applied to the side of the first adhesive material away from the first protrusion structure. The first template is used as an imprinting template, and an imprinting process is used to form a second template from the template adhesive material. The second template includes a first groove that is complementary to the protrusion structure. The first groove has a triangular cross-section along the first direction and has at least one inclined flat surface.

[0014] A second adhesive material is coated on one side of the second template with the first groove, and the second template is used as an imprinting template to form a second protrusion structure that is complementary to and corresponds to the first groove.

[0015] In some embodiments, a plurality of first protrusion structures arranged along a first direction are formed on a first substrate, including:

[0016] Multiple first protrusion structures are fabricated on a first substrate using an electron beam direct writing process. The cross-sectional shape of the first protrusion structure is a shape composed of multiple rectangles arranged closely in sequence. In the direction perpendicular to the first substrate, the thickness of the multiple rectangles is not completely equal. The multiple rectangles include: the thickest first rectangle and the thinnest second rectangle that is not adjacent to the first rectangle on one side. The thickness of the first rectangle, the rectangle between the first rectangle and the second rectangle, and the second rectangle decreases sequentially.

[0017] In some embodiments, a plurality of first protrusion structures arranged along a first direction are formed on a first substrate, including:

[0018] A first protrusion structure comprising multiple strip-shaped structures is fabricated on a first substrate using an electron beam direct writing process. The multiple strip-shaped structures are spaced apart along a first direction, and the cross-sectional shape of the strip-shaped structures is rectangular. In the direction perpendicular to the first substrate, the thickness of the multiple strip-shaped structures is not completely equal. The multiple strip-shaped structures include: a first strip-shaped structure with the thickest thickness and a second strip-shaped structure with the thinnest thickness that is not adjacent to the first strip-shaped structure on one side. The thickness of the first strip-shaped structure, the strip-shaped structure between the first and second strip-shaped structures, and the second strip-shaped structure decreases sequentially.

[0019] In some embodiments, a plurality of first protrusion structures arranged along a first direction are formed, including:

[0020] A first substrate is provided, and a plurality of third protrusion structures arranged along a first direction are formed on the first substrate to obtain a third template;

[0021] Using a third template and an imprinting process, the third adhesive material forms a first protrusion structure that corresponds one-to-one with the third protrusion structure, and the first protrusion structure is transferred onto the second substrate.

[0022] Forming a first adhesive material that covers at least a plurality of first protrusion structures and using the protrusion structures including the first protrusion structures and the first adhesive material to form a grating structure including a plurality of second protrusion structures, including:

[0023] A first adhesive material is coated on the side of the first protrusion structure away from the second substrate, and the first adhesive material is cured to form a second protrusion structure including the first adhesive material and the first protrusion structure, thereby obtaining a grating structure.

[0024] In some embodiments, a third template is used to employ an imprinting process to form a first protrusion structure corresponding one-to-one with the third protrusion structure using a third adhesive material, and the first protrusion structure is transferred onto a second substrate, including:

[0025] A template adhesive is applied to one side of the third protrusion structure, and the third template is used as an imprinting template. An imprinting process is used to form a fourth template from the template adhesive. The fourth template includes a second groove that is complementary to and corresponds to the third protrusion structure.

[0026] A third adhesive material is coated on one side of the fourth template with the second groove, and the fourth template is used as an imprinting template. An imprinting process is used to make the third adhesive material form a first protrusion structure that is complementary to and corresponds to the second groove, and the first protrusion structure is transferred onto the second substrate.

[0027] In some embodiments, a plurality of third protrusion structures arranged along a first direction are formed on a first substrate, including:

[0028] Multiple third protrusion structures are fabricated on a first substrate using an electron beam direct writing process. The cross-sectional shape of the third protrusion structure is a shape composed of multiple rectangles arranged closely in sequence. In the direction perpendicular to the first substrate, the thickness of the multiple rectangles is not completely equal. The multiple rectangles include: the thickest first rectangle and the thinnest second rectangle which is not adjacent to the first rectangle on one side. The thickness of the first rectangle, the rectangle between the first and second rectangles, and the second rectangle decreases sequentially.

[0029] In some embodiments, a plurality of third protrusion structures arranged along a first direction are formed on a first substrate, including:

[0030] A third protrusion structure comprising multiple strip-shaped structures is fabricated on a first substrate using an electron beam direct writing process. The multiple strip-shaped structures are spaced apart along a first direction, and the cross-sectional shape of the strip-shaped structures in the first direction is rectangular. In the direction perpendicular to the first substrate, the thicknesses of the multiple strip-shaped structures are not completely equal. The multiple strip-shaped structures include: a first strip-shaped structure with the thickest thickness and a second strip-shaped structure with the thinnest thickness that is not adjacent to the first strip-shaped structure on one side. The thicknesses of the first strip-shaped structure, the strip-shaped structure between the first and second strip-shaped structures, and the second strip-shaped structure decrease sequentially.

[0031] In some embodiments, the distance between two adjacent strip structures is greater than or equal to 30 nanometers and less than or equal to 200 nanometers.

[0032] In some embodiments, the period of the grating structure is greater than or equal to 300 nanometers and less than or equal to 600 nanometers.

[0033] In some embodiments, the maximum thickness of the second protrusion structure is greater than or equal to 300 nanometers and less than or equal to 600 nanometers.

[0034] This disclosure provides a grating structure, which is prepared using the grating structure preparation method provided in this disclosure.

[0035] The grating structure includes: a plurality of second protrusion structures arranged along a first direction; the cross-section of the second protrusion structure along the first direction is triangular, and the second protrusion structure has at least one inclined flat surface.

[0036] This disclosure provides a display device, which includes:

[0037] Display panel;

[0038] The light transmission layer is located on the light-emitting side of the display panel;

[0039] The grating structure provided in this embodiment is located on the side of the light transmission layer facing the display panel.

[0040] In some embodiments, the grating structure is a coupling grating of a display device; and / or,

[0041] The grating structure is a coupled grating for the display device; the display device also includes a reflective layer located on the side of the grating structure opposite to the light transmission layer. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 A schematic flowchart illustrating a method for fabricating a grating structure according to an embodiment of this disclosure;

[0044] Figure 2 A schematic flowchart illustrating another method for fabricating a grating structure provided in this embodiment of the present disclosure;

[0045] Figure 3 A schematic flowchart illustrating another method for fabricating a grating structure according to an embodiment of this disclosure;

[0046] Figure 4 A schematic flowchart illustrating another method for fabricating a grating structure according to an embodiment of this disclosure;

[0047] Figure 5 A schematic flowchart illustrating another method for fabricating a grating structure according to an embodiment of this disclosure;

[0048] Figure 6 This is a schematic diagram of a grating structure provided in an embodiment of the present disclosure;

[0049] Figure 7 This is a schematic diagram of another grating structure provided in an embodiment of the present disclosure;

[0050] Figure 8 This is a schematic diagram of another grating structure provided in an embodiment of the present disclosure;

[0051] Figure 9 T1 order diffraction efficiency results for grating structure 01 and grating structure 02 provided in the embodiments of this disclosure;

[0052] Figure 10 This is a schematic diagram of the structure of a display device provided in an embodiment of the present disclosure;

[0053] Figure 11 This is a schematic diagram of another display device provided in an embodiment of the present disclosure;

[0054] Figures 12a-12c This is a schematic diagram of an arrangement of coupling-in gratings and coupling-out gratings provided in an embodiment of this disclosure. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Furthermore, the embodiments and features in the embodiments of this disclosure can be combined with each other without conflict. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0056] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that an element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0057] It should be noted that the dimensions and shapes of the figures in the accompanying drawings do not reflect actual proportions and are intended only to illustrate the content of this disclosure. Furthermore, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0058] This disclosure provides a method for fabricating a grating structure, such as... Figure 1 As shown, it includes:

[0059] S101, forming a plurality of first protrusion structures arranged along a first direction;

[0060] S102. A first adhesive material is formed that covers at least a plurality of first protrusion structures, and a grating structure including a plurality of second protrusion structures is formed using the protrusion structures including the first protrusion structures and the first adhesive material; wherein, the surface of the first adhesive material facing away from the first protrusion structure is a flat surface, including a one-to-one correspondence between the protrusion structures of the first protrusion structure and the first adhesive material and the second protrusion structures, the shape of the cross section of the second protrusion structure along the first direction is triangular, and the second protrusion structure has at least one inclined flat surface.

[0061] It should be noted that the grating structure includes multiple second protrusions, each with a triangular cross-section along the first direction. The cross-section of the grating structure including these second protrusions is serrated. When the grating cross-section is serrated, the light energy of the grating is concentrated in a predetermined direction, i.e., at a certain spectral level. The spectral intensity is maximum when detected from this direction; this phenomenon is called blaze, and the grating is called a blazed grating. Therefore, the grating structure fabricated using the method provided in this embodiment is a blazed grating.

[0062] It should be noted that, in actual implementation, the outline of the first protrusion structure is roughly triangular, that is, the outline of the first protrusion structure has a sloping surface. Due to factors such as manufacturing process, the sloping surface corresponding to the first protrusion structure is prone to unevenness. Directly using the first protrusion structure to form the grating structure can easily affect the waveguide efficiency of the grating structure.

[0063] The method for fabricating a grating structure provided in this disclosure involves covering a first protruding structure with a first adhesive material. Even if the inclined surface of the first protruding structure is uneven, the fluidity of the first adhesive material ensures that the surface of the first adhesive material facing away from the first protruding structure becomes flat. This results in a flat surface for the protruding structure formed by the first adhesive material and the first protruding structure. When a second protruding structure is formed using the protruding structure composed of the first protruding structure and the first adhesive material, the inclined surface of the second protruding structure becomes flat, thereby avoiding any impact on the waveguide efficiency of the grating structure.

[0064] In some embodiments, the shape of the cross section of the protrusion structure composed of the first protrusion structure and the first adhesive material along the first direction is triangular.

[0065] In some embodiments, the triangle formed by the cross-section of the protruding structure composed of the first protruding structure and the first adhesive material along the first direction is substantially congruent to the triangle formed by the cross-section of the second protruding structure along the first direction. It should be noted that "substantially congruent" means that the triangle formed by the cross-section of the protruding structure composed of the first protruding structure and the first adhesive material along the first direction is congruent to the triangle formed by the cross-section of the second protruding structure along the first direction, or that the dimensional difference between the triangle formed by the cross-section of the protruding structure composed of the first protruding structure and the first adhesive material along the first direction and the triangle formed by the cross-section of the second protruding structure along the first direction is considered congruent if it satisfies the requirements of manufacturing tolerances.

[0066] In some embodiments, such as Figure 2 , Figure 3 As shown, in step S101, a plurality of first protrusion structures arranged along a first direction are formed, including:

[0067] S1011. A first substrate 1 is provided, and a plurality of first protrusion structures 2 arranged along a first direction X are formed on the first substrate 1;

[0068] Step S102 involves forming a first adhesive material that covers at least a plurality of first protrusion structures and forming a grating structure using the protrusion structures formed by the first protrusion structures and the first adhesive material, including:

[0069] S1021. A first adhesive material 3 covering the first protruding structure 2 is formed, and the first adhesive material 3 is cured to form a plurality of protruding structures including the first protruding structure 2 and the first adhesive material 3, thereby obtaining a first template 5. For ease of distinction, the plurality of protruding structures including the first protruding structure 2 and the first adhesive material 3 formed in this step are named the fourth protruding structure 4, wherein the shape of the fourth protruding structure 4 along the first direction X section is triangular, and the fourth protruding structure 4 has at least one inclined flat surface.

[0070] S1022. Provide a second adhesive material 6, and use the first template 5 as an imprinting template. Use an imprinting process to form a second protrusion structure 7 that corresponds one-to-one with the fourth protrusion structure 4 on the second adhesive material 6, and transfer the second protrusion structure 7 onto the second substrate 12 to obtain a grating structure.

[0071] In some embodiments, such as Figure 2 , Figure 3 As shown, step S1022 uses the first template as an imprinting template and employs an imprinting process to form a second protrusion structure in the second adhesive material that corresponds one-to-one with the fourth protrusion structure, including:

[0072] S1022-1. A template adhesive 8 is coated on the side of the first adhesive 3 away from the first protrusion structure 2, and the first template 5 is used as an imprinting template. An imprinting process is used to form a second template 9 from the template adhesive 8. The second template 9 includes a first groove 10 that is complementary to the fourth protrusion structure 4. The shape of the first groove 10 in the cross section along the first direction X is triangular, and the first groove 10 has at least one inclined flat surface.

[0073] S1022-2, A second adhesive material 6 is coated on one side of the second template 9 with the first groove 10, and the second template 9 is used as an imprinting template to perform an imprinting process so that the second adhesive material 6 forms a second protrusion structure 7 that is complementary to and corresponds to the first groove 10.

[0074] In some embodiments, the refractive index of the second adhesive material is equal to the refractive index of the second substrate.

[0075] In a practical implementation, the second substrate is, for example, a glass substrate. The refractive index of the second adhesive material is equal to the refractive index of the glass substrate.

[0076] In some embodiments, such as Figure 2As shown, step S1011 involves fabricating a plurality of first protrusion structures arranged along a first direction on the first substrate, including:

[0077] Multiple first protrusion structures 2 are fabricated on a first substrate 1 using an electron beam direct writing process. The cross-sectional shape of the first protrusion structure 2 is a shape composed of multiple rectangles arranged in close succession. In the direction Y perpendicular to the first substrate, the thickness h of the multiple rectangles is not completely equal. The multiple rectangles include: the thickest first rectangle 25 and the thinnest second rectangle 26 which is not adjacent to the first rectangle 25 on one side. The thickness of the first rectangle 25, the rectangle between the first rectangle 25 and the second rectangle 26, and the second rectangle 26 decreases sequentially.

[0078] It should be noted that, Figure 2 The thickness of the first rectangle 25 is only shown in the diagram.

[0079] like Figure 2 As shown, the cross-sectional shape of the first protrusion is approximately triangular. That is, the outline of the first protrusion has a sloping surface. Due to manufacturing factors, the sloping surface of the first protrusion is prone to unevenness, such as steps. Therefore, the cross-sectional shape of the first protrusion is composed of multiple rectangles arranged closely together. That is, as... Figure 2 As shown, the hypotenuse of the cross-section of the first protrusion is not straight but serrated, and the hypotenuse of the triangle with an angle greater than 0 and less than 90 degrees with the first direction is serrated. That is, the inclined surface of the first protrusion is a non-flat surface of the step surface. When the first adhesive material covers the inclined surface of the first protrusion, due to the fluidity of the first adhesive material, the first adhesive material can fill the step surface, thereby forming a flat inclined surface on the side of the first adhesive material away from the first protrusion.

[0080] Alternatively, in some embodiments, such as Figure 3 As shown, step S1011 involves fabricating a plurality of first protrusion structures arranged along a first direction on the first substrate, including:

[0081] A first protrusion structure 2 comprising multiple strip structures 11 is fabricated on a first substrate 1 using an electron beam direct writing process. The multiple strip structures 11 are arranged at intervals along a first direction X, and the cross-sectional shape of each strip structure 11 is rectangular. In the direction Y perpendicular to the first substrate, the thickness h' of the multiple strip structures 11 is not completely equal. The multiple strip structures 11 include: a first strip structure 27 with the thickest thickness and a second strip structure 28 with the thinnest thickness that is not adjacent to the first strip structure 27 on one side. The thickness of the strip structure 11 between the first strip structure 27 and the second strip structure 28 and the second strip structure 28 decreases sequentially.

[0082] It should be noted that, Figure 3The thickness of the first strip structure 27 is only shown in the diagram.

[0083] In some embodiments, the width of the plurality of strip structures is the same in the first direction.

[0084] The first protruding structure includes multiple strip-shaped structures, which are equivalent to the first protruding structure including a grating. The thickness of the strip-shaped structures is not exactly the same. The grating included in the first protruding structure serves as a frame, and the outline of the frame is approximately triangular. When the first adhesive material covers the multiple strip-shaped structures, due to the fluidity of the first adhesive material and the close distance between adjacent strip-shaped structures, the first adhesive material can fill the gaps between the strip-shaped structures, so that the multiple strip-shaped structures are connected by the first adhesive material, and a beveled surface with a flat surface is formed on the side of the strip-shaped structure where the thickness varies.

[0085] In some embodiments, the sum of the distance between two adjacent strip structures in the first direction and the width of the strip structure is greater than or equal to 30 nanometers and less than or equal to 200 nanometers. That is, the period of the grating included in the first protrusion structure is greater than or equal to 30 nanometers and less than or equal to 200 nanometers.

[0086] In some embodiments, the thickness difference between two adjacent strip structures perpendicular to the first direction is greater than or equal to 30 nanometers and less than or equal to 600 nanometers.

[0087] It should be noted that, Figure 2 , Figure 3 An example is given of fabricating a grating structure with a second protrusion using a protrusion structure comprising a first protrusion and a first adhesive material as a template. In practice, other methods can also be used to obtain the grating structure using a protrusion structure comprising a first protrusion and a first adhesive material.

[0088] In some embodiments, such as Figure 4 , Figure 5 As shown, step S101 forms a plurality of first protrusion structures arranged along a first direction, including:

[0089] S1011. Provide a first substrate 1, and fabricate a plurality of third protrusion structures 13 arranged along the first direction X on the first substrate 1 to obtain a third template 14.

[0090] S1012. Using the third template 14, an imprinting process is used to form a first protrusion structure 2 on the third adhesive material 15 that corresponds one-to-one with the third protrusion structure 13, and the first protrusion structure 2 is transferred onto the second substrate 12.

[0091] Step S102 involves forming a first adhesive material that at least covers a plurality of first protrusion structures and using the protrusion structures including the first protrusion structures and the first adhesive material to form a grating structure including a plurality of second protrusion structures, including:

[0092] S1021. A first adhesive material 3 is coated on the side of the first protrusion structure 2 away from the second substrate 12, and the first adhesive material 3 is cured to form a protrusion structure including the first adhesive material 3 and the first protrusion structure 2 as the second protrusion structure 7, thereby obtaining a grating structure.

[0093] In some embodiments, the refractive index of the third adhesive material is equal to the refractive index of the second substrate.

[0094] In some embodiments, the second substrate is a glass substrate. The refractive index of the corresponding third adhesive material is equal to that of the glass substrate.

[0095] In some embodiments, the first adhesive material and the third adhesive material are made of the same material. Alternatively, the first adhesive material and the third adhesive material are made of different materials, but have the same refractive index. Alternatively, the first adhesive material and the third adhesive material are made of different materials, and the refractive index of the first adhesive material is greater than that of the third adhesive material.

[0096] In some embodiments, such as Figure 4 , Figure 5 As shown, step S1012 utilizes a third template and an imprinting process to form a first protrusion structure corresponding one-to-one with the third protrusion structure using the third adhesive material, and transfers the first protrusion structure onto the second substrate, including:

[0097] S1012-1. A template adhesive 8 is coated on one side of the third protrusion structure 13, and the third template 14 is used as an imprinting template. An imprinting process is used to form a fourth template 16 from the template adhesive 8. The fourth template 16 includes a second groove 17 that is complementary to and corresponds to the third protrusion structure 13.

[0098] S1012-2. A third adhesive material 15 is coated on the side of the fourth template 16 with the second groove 17, and the fourth template 16 is used as an imprinting template. An imprinting process is used to form a first protrusion structure 2 of the third adhesive material 15 that is complementary to the second groove 17, and the first protrusion structure 2 is transferred onto the second substrate 12.

[0099] In some embodiments, such as Figure 4 As shown, step S1012 involves fabricating a plurality of third protrusion structures arranged along a first direction on the first substrate, including:

[0100] Multiple third protrusion structures 13 with approximately triangular cross-sections are fabricated on the first substrate 1 using an electron beam direct writing process. The cross-sectional shape of the third protrusion structure 13 is composed of multiple rectangles arranged closely in sequence. In the direction Y perpendicular to the first substrate, the thickness h of the multiple rectangles is not completely equal. The multiple rectangles include: the thickest first rectangle 25 and the thinnest second rectangle 26 which is not adjacent to the first rectangle 25 on one side. The thickness of the first rectangle 25, the rectangle between the first rectangle 25 and the second rectangle 26, and the second rectangle 26 decreases sequentially.

[0101] It should be noted that, Figure 4 The thickness of the first rectangle 25 is only shown in the diagram.

[0102] like Figure 4 As shown, the cross-sectional shape of the third protrusion is roughly triangular. That is, the outline of the third protrusion has a sloping surface. Due to manufacturing factors, the sloping surface of the third protrusion is prone to unevenness, such as steps. Therefore, the cross-sectional shape of the third protrusion is composed of multiple rectangles arranged closely together. That is, as... Figure 4 As shown, the hypotenuse of the third protrusion structure 13 is not straight but serrated, and the hypotenuse of the triangle with an angle greater than 0 and less than 90 degrees with the first direction is a serrated edge, that is, the inclined surface of the third protrusion structure 13 is a non-flat surface of the step surface.

[0103] Correspondingly, the second groove 17, complementary to the third protrusion structure 13, has a roughly triangular cross-section along the first direction X, and the hypotenuse of the triangle is not straight but serrated. Similarly, the first protrusion structure 2, complementary to the second groove 17, has a roughly triangular cross-section along the first direction X, and the hypotenuse of the triangle is not straight but serrated. That is, the inclined surface of the first protrusion structure is a non-flat surface of a stepped surface. Figure 4 As shown, the cross-sectional shape of the first protrusion structure 2 is composed of multiple rectangles arranged closely in sequence. In the direction Y perpendicular to the second substrate, the thicknesses of the multiple rectangles are not completely equal. The multiple rectangles include: the thickest first rectangle 25 and the thinnest second rectangle 26, which is not adjacent to the first rectangle 25 on one side. The thicknesses of the first rectangle 25, the rectangle between the first rectangle 25 and the second rectangle 26, and the second rectangle 26 decrease sequentially. When the first adhesive material covers the inclined surface of the first protrusion structure, due to the fluidity of the first adhesive material, it can fill the plateau step surface, thereby forming a flat inclined surface on the side of the first adhesive material away from the first protrusion structure.

[0104] Alternatively, in some embodiments, such as Figure 5 As shown, step S1012 involves fabricating a plurality of third protrusion structures arranged along a first direction on the first substrate, including:

[0105] A third protrusion structure 13 comprising multiple strip structures 11 is fabricated on a first substrate 1 using an electron beam direct writing process. The multiple strip structures 11 are arranged at intervals along a first direction X, and the cross-sectional shape of each strip structure 11 is rectangular. In the direction Y perpendicular to the first substrate, the thicknesses of the multiple strip structures 11 are not completely equal. The multiple strip structures 11 include: a first strip structure 27 with the thickest thickness and a second strip structure 28 with the thinnest thickness that is not adjacent to the first strip structure 27 on one side. The thicknesses of the strip structures 11 between the first strip structure 27 and the second strip structure 28 and the second strip structure 28 decrease sequentially.

[0106] It should be noted that, Figure 5 The thickness of the first strip structure 27 is only shown in the diagram.

[0107] In some embodiments, the width of the plurality of strip structures is the same in the first direction.

[0108] It should be noted that the third protrusion structure comprises multiple strip-shaped structures, which is equivalent to the first protrusion structure comprising a grating. The thickness of these strip-shaped structures is not entirely uniform; that is, the grating included in the third protrusion structure acts as a frame, and the outline of the frame is approximately triangular. Correspondingly, as... Figure 5 As shown, the second groove 17, complementary to the third protrusion structure 13, includes a plurality of strip-shaped sub-grooves 18. The first protrusion structure 2, complementary to the second groove 17, also includes a plurality of strip-shaped structures 11. The plurality of strip-shaped structures 11 are spaced apart along the first direction X. The cross-sectional shape of each strip-shaped structure 11 is rectangular. In the direction Y perpendicular to the second substrate, the thickness of the plurality of strip-shaped structures 11 is not completely equal. The plurality of strip-shaped structures 11 includes: the thickest first strip-shaped structure 27 and the thinnest second strip-shaped structure 28 which is not adjacent to the first strip-shaped structure 27 on one side, the strip-shaped structure 11 between the first strip-shaped structure 27 and the second strip-shaped structure 28, and the second strip-shaped structure 28. When the first adhesive material covers the plurality of strip-shaped structures of the first protrusion structure, due to the fluidity of the first adhesive material and the close distance between adjacent strip-shaped structures, the first adhesive material can fill the gaps between the strip-shaped structures, so that the plurality of strip-shaped structures are connected by the first adhesive material, and a sloped surface with a flat surface is formed on the side of the strip-shaped structure with a thickness variation.

[0109] In some embodiments, the sum of the distance between two adjacent strip structures in the first direction and the width of the strip structure is greater than or equal to 30 nanometers (nm) and less than or equal to 200 nm. That is, the period of the grating included in the first protrusion structure is greater than or equal to 30 nm and less than or equal to 200 nm.

[0110] In some embodiments, the thickness difference between two adjacent strip structures perpendicular to the first direction is greater than or equal to 30 nm and less than or equal to 600 nm.

[0111] It should be noted that, Figures 2-5 Taking the example of a second protruding structure with a right-angled triangle cross-section and its right-angled side perpendicular to the first direction, the following explanation is provided: the second protruding structure has one inclined surface. In practice, the second protruding structure can have two inclined surfaces, and its cross-section can be either a right-angled triangle or a non-right-angled triangle. When the cross-section is a right-angled triangle, all the right-angled sides of the triangle form an angle with the first direction.

[0112] Based on the same inventive concept, this disclosure also provides a grating structure, which is prepared by the grating structure preparation method provided in this disclosure.

[0113] like Figure 6 , Figure 7 As shown, the grating structure includes: a plurality of second protrusion structures 7 arranged along the first direction X; the shape of the cross section of the second protrusion structure 7 along the first direction X is triangular, and the second protrusion structure 7 has at least one inclined flat surface.

[0114] In some embodiments, such as Figure 6 , Figure 7 , Figure 8 As shown, the grating structure also includes a second substrate 12.

[0115] In some embodiments, such as Figure 6 As shown, the second protrusion structure 7 includes a second adhesive material 6 located on one side of the second substrate 12.

[0116] In some embodiments, such as Figure 7 , Figure 8 As shown, the second protrusion structure 7 includes: a first protrusion structure 2 located on one side of the second substrate 12 and a first adhesive material 3 covering the first protrusion structure 2 on the side of the first protrusion structure 2 away from the second substrate 12.

[0117] In specific implementation, the first protrusion structure includes the third adhesive material, that is, the second protrusion structure includes the third adhesive material and the first adhesive material.

[0118] In some embodiments, such as Figure 7 As shown, the cross-sectional shape of the first protrusion structure 2 along the first direction X is approximately triangular. Figure 7 In the first protrusion structure 2, the hypotenuse of the cross section along the first direction X is sawtooth-shaped.

[0119] Alternatively, in some embodiments, such as Figure 8As shown, the first protrusion structure 2 includes a plurality of strip structures 11 arranged at intervals along the first direction X; the thickness of each strip structure 11 is the same in different regions, but the thickness of the plurality of strip structures 11 is not completely equal in the direction Y perpendicular to the second substrate. The plurality of strip structures 11 include: the thickest first strip structure 27 and the thinnest second strip structure 28 which is not adjacent to the first strip structure 27 on one side. The thickness of the strip structure 11 between the first strip structure 27 and the second strip structure 28 and the second strip structure 28 decreases sequentially.

[0120] In some embodiments, the sum of the distance between two adjacent strip structures in the first direction and the width of the strip structure is greater than or equal to 30 nm and less than or equal to 200 nm.

[0121] In some embodiments, the period of the grating structure is greater than or equal to 300 nm and less than or equal to 600 nm.

[0122] In some embodiments, the maximum thickness of the second protrusion structure is greater than or equal to 300 nm and less than or equal to 600 nm.

[0123] Next, the simulation results of the grating structure provided in the embodiments of this disclosure will be introduced. The second protrusion structure of the grating structure 01 includes a first adhesive material and a third adhesive material, and the grating structure 01 is, for example, with... Figure 7 The grating structure shown is similar, that is, the third adhesive material 15 forms the first protrusion structure 2, and the first adhesive material covers the first protrusion structure 2; the second protrusion structure of the grating structure 02 includes the second adhesive material, and the grating structure 02 is, for example, similar to... Figure 6 The grating structures shown are similar, with the second protrusion structure 7 including the second adhesive material 6. The relevant parameters of grating structures 01 and 02 are as follows: the refractive index of the first adhesive material is 1.9, and the refractive indices of the second and third adhesive materials are 1.7; the period of both grating structures 01 and 02 is 415 nm; the maximum thickness of both grating structures 01 and 02 is 400 nm; the duty cycle of both grating structures 01 and 02 is 0.8; and the maximum width of the second protrusion structure of both grating structures 01 and 02 in the first direction is 80 nm. The cross-section of the first protrusion structure of grating structure 01 consists of three closely arranged rectangles with thicknesses of 280 nm, 160 nm, and 80 nm, respectively. The diffraction efficiency of grating structures 01 and 02 is simulated, and the T1 order diffraction efficiency of grating structures 01 and 02 is as follows: Figure 9 As shown. From Figure 9As can be seen, when the second protrusion structure includes two adhesive materials with different refractive indices, the T1-order diffraction of the blazed grating is optimized by the difference in refractive indices of the two adhesive materials, thereby improving the diffraction efficiency. When the grating structure is applied to AR display products, it can increase the efficiency of the optical waveguide grating of the AR display product, and ultimately improve the overall light efficiency of the AR display product.

[0124] This disclosure provides a display device, such as... Figure 10 , Figure 11 As shown, the display device includes:

[0125] Display panel 19;

[0126] The light transmission layer 20 is located on the light-emitting side of the display panel 19;

[0127] The grating structure 21 provided in this embodiment is located on the side of the light transmission layer 20 facing the display panel 19.

[0128] In some embodiments, such as Figure 10 , Figure 11 As shown, the display device includes an input grating 22 and an output grating 23; both the input grating 22 and the output grating 23 are located on the side of the light transmission layer 20 facing the display panel 19.

[0129] In some embodiments, such as Figure 10 , Figure 11 As shown, the coupled grating 22 is the grating structure 21 provided in the embodiments of this disclosure.

[0130] It should be noted that, as Figure 10 As shown, the output grating 23 is a strip grating. When only the input grating 22 is the grating structure 21 provided in this embodiment, when the user uses the display device, the human eye and the display panel are on the same side, that is, on the side of the input grating 22 and the output grating 23 away from the light transmission layer 20.

[0131] In some embodiments, such as Figure 11 As shown, the coupling grating 23 is the grating structure 21 provided in the embodiments of this disclosure;

[0132] The display device also includes a reflective layer 24 located on the side of the grating structure 21 opposite to the light transmission layer 20.

[0133] It should be noted that, as Figure 11 As shown, when the output grating 23 is the grating structure 21 provided in the embodiments of this disclosure, when the user uses the display device, the human eye is located on the side of the light transmission layer 20 away from the output grating 23.

[0134] It should be noted that, Figure 11 In this embodiment, the coupled grating 22 is also the grating structure 21 provided in this disclosure.

[0135] In some embodiments, the reflective layer is made of materials such as aluminum or titanium dioxide.

[0136] The following example uses a grating structure provided at least in the embodiments of this disclosure, such as... Figures 12a-12c The arrangement of the input and output gratings is illustrated below. Figure 12a , Figure 12b In this context, the coupling grating 23 is a one-dimensional grating, for example, the coupling grating 23 is a strip grating, including multiple strip structures 29 with rectangular cross sections; Figure 12a In the coupling grating 22, the arrangement direction of the plurality of second protrusion structures 7 is the same as the arrangement direction of the plurality of strip structures 29 included in the coupling grating 23. The plurality of second protrusion structures 7 included in the coupling grating 22 and the plurality of strip structures 29 included in the coupling grating 23 are both arranged along the first direction X. Figure 12b In the coupling grating 22, the arrangement direction of the plurality of second protrusion structures 7 intersects with the arrangement direction of the plurality of strip structures 29 included in the coupling grating 23. The plurality of second protrusion structures 7 included in the coupling grating 22 are arranged along the first direction X, and the plurality of strip structures 29 included in the coupling grating 23 are arranged along the second direction Y'. Figure 12b In the first direction X, the second direction Y' is perpendicular to the second direction; of course, the coupling grating can also be the grating structure provided in the embodiments of this disclosure, and the arrangement of the multiple second protrusion structures is the same as the arrangement of the multiple strip structures, which will not be described again here. Figure 12c The output grating 23 is a two-dimensional grating, including multiple grating substructures 30 arranged in an array along the first direction X and the second direction Y'. The input grating 22 includes multiple second protrusion structures 7 arranged along the first direction X.

[0137] The display device provided in this disclosure is any product or component with display function, such as a television or monitor. Other essential components of this display device are understood by those skilled in the art and will not be described in detail here, nor should they be construed as limiting this disclosure. Implementation of this display device can refer to the embodiments of the grating structure described above; repeated details will not be repeated.

[0138] In summary, the grating structure, its fabrication method, and display device provided in this disclosure cover the first protruding structure with a first adhesive material. Even if the inclined surface of the first protruding structure is uneven, the fluidity of the first adhesive material ensures that the surface of the first adhesive material facing away from the first protruding structure becomes flat, thus making the surface of the protruding structure composed of the first adhesive material and the first protruding structure flat. When a second protruding structure is formed using the protruding structure composed of the first protruding structure and the first adhesive material, the inclined surface of the second protruding structure becomes flat, thereby avoiding any impact on the waveguide efficiency of the grating structure.

[0139] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0140] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. A method for fabricating a grating structure, wherein, The method includes: Multiple first protrusion structures are formed along a first direction; A first adhesive material is formed to at least cover the plurality of first protruding structures, and a grating structure including a plurality of second protruding structures is formed using the protruding structures including the first protruding structures and the first adhesive material; wherein, the surface of the first adhesive material facing away from the first protruding structure is a flat surface; the protruding structures including the first protruding structures and the first adhesive material correspond one-to-one with the second protruding structures, the shape of the cross section of the second protruding structure along the first direction is triangular, and the second protruding structure has at least one inclined flat surface.

2. The method according to claim 1, wherein, Forming multiple first protrusion structures arranged along a first direction, including: A first substrate is provided, and a plurality of the first protrusion structures arranged along the first direction are formed on the first substrate; Forming a first adhesive material that at least covers the plurality of first protrusion structures and using the protrusion structure including the first protrusion structures and the first adhesive material to form a grating structure including a plurality of second protrusion structures, including: A first adhesive material is formed to cover the first protruding structure, and the first adhesive material is cured to form a plurality of the protruding structures including the first protruding structure and the first adhesive material, thereby obtaining a first template; wherein, the shape of the cross section of the protruding structure along the first direction is triangular, and the protruding structure has at least one inclined flat surface; A second adhesive material is provided, and the first template is used as an imprinting template. An imprinting process is used to form a second protrusion structure that corresponds one-to-one with the protrusion structure. The second protrusion structure is then transferred onto a second substrate to obtain the grating structure.

3. The method according to claim 2, wherein, Using the first template as an imprinting template, an imprinting process is employed to form a second protruding structure in the second adhesive material that corresponds one-to-one with the protruding structure, including: A template adhesive is applied to the side of the first adhesive material away from the first protrusion structure. The first template is used as an imprinting template, and an imprinting process is used to form a second template from the template adhesive material. The second template includes a first groove that is complementary to the protrusion structure. The first groove has a triangular cross-section along the first direction and has at least one inclined flat surface. The second adhesive material is coated on the side of the second template with the first groove, and the second template is used as an imprinting template. An imprinting process is used to make the second adhesive material form a second protrusion structure that is complementary to and corresponds to the first groove.

4. The method according to claim 2 or 3, wherein, A plurality of the first protrusion structures arranged along the first direction are fabricated on the first substrate, including: Multiple first protrusion structures are fabricated on the first substrate using an electron beam direct writing process; wherein the cross-sectional shape of the first protrusion structure is a shape composed of multiple rectangles arranged closely in sequence; in the direction perpendicular to the first substrate, the thickness of the multiple rectangles is not completely equal, and the multiple rectangles include: the thickest first rectangle and the thinnest second rectangle on one side of the first rectangle that is not adjacent to the first rectangle, and the thickness of the first rectangle, the rectangle between the first rectangle and the second rectangle, and the second rectangle decreases sequentially.

5. The method according to claim 2, wherein, A plurality of the first protrusion structures arranged along the first direction are fabricated on the first substrate, including: The first protrusion structure, comprising multiple strip-shaped structures, is fabricated on the first substrate using an electron beam direct writing process. The multiple strip-shaped structures are spaced apart along the first direction, and each strip-shaped structure has a rectangular cross-sectional shape. In the direction perpendicular to the first substrate, the thicknesses of the multiple strip-shaped structures are not entirely equal. Each multiple strip-shaped structure includes: a first strip-shaped structure with the thickest thickness and a second strip-shaped structure with the thinnest thickness that is not adjacent to the first strip-shaped structure on one side. The thicknesses of the first strip-shaped structure, the rectangle between the first and second strip-shaped structures, and the second strip-shaped structure decrease sequentially.

6. The method according to claim 1, wherein, Forming a plurality of first protrusion structures arranged along a first direction, including: A first substrate is provided, and a plurality of third protrusion structures arranged along the first direction are formed on the first substrate to obtain a third template; Using the third template, an imprinting process is employed to form a first protrusion structure in the third adhesive material that corresponds one-to-one with the third protrusion structure, and the first protrusion structure is transferred onto the second substrate; Forming a first adhesive material that at least covers the plurality of first protrusion structures and using the protrusion structures including the first protrusion structures and the first adhesive material to form a grating structure including a plurality of second protrusion structures, including: The first adhesive material is coated on the side of the first protrusion structure away from the second substrate, and the first adhesive material is cured to form a second protrusion structure including the first adhesive material and the first protrusion structure, thereby obtaining the grating structure.

7. The method according to claim 6, wherein, Using the third template, an imprinting process is employed to form a first protrusion structure in the third adhesive material that corresponds one-to-one with the third protrusion structure, and the first protrusion structure is transferred onto the second substrate, including: A template adhesive is applied to one side of the third protruding structure, and the third template is used as an imprinting template. An imprinting process is used to form a fourth template from the template adhesive. The fourth template includes a second groove that is complementary to and corresponds to the third protruding structure. The third adhesive material is coated on the side of the fourth template with the second groove, and the fourth template is used as an imprinting template. An imprinting process is used to form the third adhesive material into the first protrusion structure that is complementary to the second groove, and the first protrusion structure is transferred onto the second substrate.

8. The method according to claim 6 or 7, wherein, A plurality of third protrusion structures arranged along the first direction are fabricated on a first substrate, including: Multiple third protrusion structures are fabricated on the first substrate using an electron beam direct writing process; wherein the cross-sectional shape of the third protrusion structure is a shape composed of multiple rectangles arranged closely in sequence; in the direction perpendicular to the first substrate, the thickness of the multiple rectangles is not completely equal, and the multiple rectangles include: a first rectangle with the thickest thickness and a second rectangle with the thinnest thickness that is not adjacent to the first rectangle on one side, and the thickness of the first rectangle, the rectangle between the first rectangle and the second rectangle, and the second rectangle decreases sequentially.

9. The method according to claim 6, wherein, A plurality of third protrusion structures arranged along the first direction are fabricated on a first substrate, including: The third protrusion structure, comprising multiple strip-shaped structures, is fabricated on the first substrate using an electron beam direct writing process. The multiple strip-shaped structures are spaced apart along the first direction, and the cross-sectional shape of each strip-shaped structure in the first direction is rectangular. In the direction perpendicular to the first substrate, the thicknesses of the multiple strip-shaped structures are not entirely equal. Each multiple strip-shaped structure includes: a first strip-shaped structure with the thickest thickness and a second strip-shaped structure with the thinnest thickness that is not adjacent to the first strip-shaped structure on one side. The thicknesses of the first strip-shaped structure, the strip-shaped structures between the first and second strip-shaped structures, and the second strip-shaped structure decrease sequentially.

10. The method according to claim 5 or 9, wherein, The sum of the distance between two adjacent strip structures in the first direction and the width of the strip structure in the first direction is greater than or equal to 30 nanometers and less than or equal to 200 nanometers.

11. The method according to any one of claims 1-3, 5-7, and 9, wherein, The period of the grating structure is greater than or equal to 300 nanometers and less than or equal to 600 nanometers.

12. The method according to any one of claims 1-3, 5-7, and 9, wherein, The maximum thickness of the second protrusion structure is greater than or equal to 300 nanometers and less than or equal to 600 nanometers.

13. A grating structure, wherein, The grating structure is prepared by the method according to any one of claims 1 to 12; The grating structure includes: a plurality of second protrusion structures arranged along a first direction; the cross-section of the second protrusion structure along the first direction is triangular, and the second protrusion structure has at least one inclined flat surface.

14. A display device, wherein, The display device includes: Display panel; The light transmission layer is located on the light-emitting side of the display panel. The grating structure according to claim 13 is located on the side of the light transmission layer facing the display panel.

15. The display device according to claim 14, wherein, The grating structure is the coupling grating of the display device; and / or, The grating structure is the coupling grating of the display device; The display device further includes a reflective layer located on the side of the grating structure opposite to the light transmission layer.

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