Liquid crystal grating, lamination method for liquid crystal grating, and three-dimensional display apparatus

Abstract

A liquid crystal grating and a lamination method therefor, and a three-dimensional display apparatus. The liquid crystal grating (100) comprises at least one liquid crystal grating unit (10), which comprises a liquid crystal cell (101) and a functional film layer (102) located on one side of the liquid crystal cell (101), wherein the functional film layer (102) comprises at least two functional sub-layers (1021) arranged in a stacked manner, and edges of the at least two functional sub-layers (1021) are at least partially flush with each other in a direction perpendicular to the plane where the functional film layer (102) is located.

Description

Liquid crystal gratings and their bonding methods, 3D display devices

[0001] This application claims priority to Chinese Patent Application No. 202410706140.4, filed with the Chinese Patent Office on May 31, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of display technology, such as a liquid crystal grating and a method for bonding liquid crystal gratings, and a three-dimensional display device. Background Technology

[0003] To meet the demand for stereoscopic displays in electronic devices, electronic devices with three-dimensional (3D) holographic display capabilities have become a major development direction in the display field. Electronic devices can achieve 3D holographic display functionality by integrating holographic display systems.

[0004] As an important component of 3D display devices, liquid crystal gratings typically include a linear gate electrode structure formed by high-density, short-period long indium tin oxide (ITO) traces. During the fabrication process of liquid crystal gratings, multiple bonding processes are usually required, which can generate stress on the gratings. This can easily lead to the problem of ITO trace breakage due to localized pressure. Since the liquid crystal at the breakage location cannot be driven normally, it becomes a visible line defect under backlight and polarizer, which in turn affects the performance of the 3D display device.

[0005] Summary of the Invention

[0006] This application provides a liquid crystal grating, a method for bonding the liquid crystal grating, and a three-dimensional display device, so as to reduce the number of bonding operations of the liquid crystal grating, reduce the probability of grid electrode breakage in the liquid crystal cell, and improve the stability and reliability of the liquid crystal grating.

[0007] In a first aspect, embodiments of this application provide a liquid crystal grating, including at least one liquid crystal grating unit, wherein the liquid crystal grating unit includes a liquid crystal cell and a functional film layer located on one side of the liquid crystal cell;

[0008] The functional membrane layer includes at least two functional sublayers stacked together, and at least a portion of the edges of the at least two functional sublayers are flush along a direction perpendicular to the plane in which the functional membrane layer is located.

[0009] Secondly, embodiments of this application also provide a method for bonding liquid crystal gratings, including:

[0010] It provides at least two functional sublayers and at least one liquid crystal cell;

[0011] The at least two functional sublayers are laminated together to form a functional film layer;

[0012] The functional film layer is attached to one side of the liquid crystal cell to form a liquid crystal grating unit of the liquid crystal grating.

[0013] Thirdly, embodiments of this application also provide a three-dimensional display device, including a backlight module, a spatial light modulator, a converging field lens, and a liquid crystal grating as described in any of the first aspects, stacked sequentially.

[0014] The backlight module is configured to provide the field-sequence collimated coherent backlight required for display.

[0015] The spatial light modulator is configured to modulate the phase and amplitude of the field-sequence collimated coherent backlight;

[0016] The converging field mirror is configured to converge the modulated field-sequence collimated coherent backlight onto the liquid crystal grating;

[0017] The liquid crystal grating is configured to transmit the left-eye and right-eye images from the three-dimensional optical image to the human eye. Attached Figure Description

[0018] Figure 1 is a schematic diagram of a liquid crystal grating;

[0019] Figure 2 is a schematic diagram of the structure of the first type of liquid crystal grating provided in the embodiment of this application;

[0020] Figure 3 is a schematic diagram of the structure of the second type of liquid crystal grating provided in the embodiment of this application;

[0021] Figure 4 is a schematic diagram of the structure of the third type of liquid crystal grating provided in the embodiment of this application;

[0022] Figure 5 is a schematic diagram of the structure of the fourth type of liquid crystal grating provided in the embodiment of this application;

[0023] Figure 6 is a schematic diagram of the structure of the fifth type of liquid crystal grating provided in the embodiment of this application;

[0024] Figure 7 is a schematic diagram of the sixth type of liquid crystal grating provided in the embodiments of this application;

[0025] Figure 8 is a structural schematic diagram of the seventh type of liquid crystal grating provided in the embodiments of this application;

[0026] Figure 9 is a schematic diagram of the structure of the eighth type of liquid crystal grating provided in the embodiment of this application;

[0027] Figure 10 is a schematic diagram of the structure of a liquid crystal cell in a liquid crystal grating provided in an embodiment of this application;

[0028] Figure 11 is a process flow diagram of the first liquid crystal grating bonding method provided in the embodiment of this application;

[0029] Figure 12 is a schematic diagram of the bonding process of the first liquid crystal grating bonding method provided in the embodiment of this application;

[0030] Figure 13 is a schematic diagram of the structure corresponding to the bonding process of the first half-wave plate and the second half-wave plate provided in the embodiment of this application;

[0031] Figure 14 is a schematic diagram of the bonding process of a liquid crystal grating bonding method;

[0032] Figure 15 is a process flow diagram of the second liquid crystal grating bonding method provided in the embodiment of this application;

[0033] Figure 16 is a schematic diagram of the bonding process of the second liquid crystal grating bonding method provided in the embodiment of this application;

[0034] Figure 17 is a process flow diagram of the third liquid crystal grating bonding method provided in the embodiments of this application;

[0035] Figure 18 is a schematic diagram of the bonding process of the third liquid crystal grating bonding method provided in the embodiments of this application;

[0036] Figure 19 is a process flow diagram of the fourth liquid crystal grating bonding method provided in the embodiments of this application;

[0037] Figure 20 is a schematic diagram of the bonding process of the fourth liquid crystal grating bonding method provided in the embodiments of this application;

[0038] Figure 21 is a schematic diagram of the structure of a three-dimensional display device provided in an embodiment of this application. Detailed Implementation

[0039] The present application will now be described in conjunction with the accompanying drawings and embodiments. The embodiments described herein are for the purpose of explaining the present application. For ease of description, only the parts of the structure relevant to the present application are shown in the drawings.

[0040] Figure 1 is a schematic diagram of a liquid crystal grating structure. As shown in Figure 1, the liquid crystal cell 101' is first bonded to one of the functional sublayers 1021' of the functional film layer 102', and then the bonded structure is bonded to another functional sublayer 1021'. Due to factors such as bonding process errors, it is impossible to guarantee that the edges of the functional sublayers 1021' in the functional film layer 102' are flush. Moreover, bonding a single liquid crystal grating unit requires at least two soft-to-hard bonding processes. When the liquid crystal grating includes three liquid crystal grating units, the number of soft-to-hard bonding processes is eight. The large number of bonding processes leads to the liquid crystal grating being subjected to multiple stresses during the bonding process, which can cause the gate electrode to break.

[0041] The solution in this application embodiment is to first bond the functional sublayer to form a functional film layer, and then bond the functional film layer to the liquid crystal cell. This reduces the number of bonding steps, thereby reducing the number of stresses generated during the bonding process of the liquid crystal grating, and preventing the gate electrode from breaking due to the liquid crystal grating being subjected to multiple stresses during the bonding process.

[0042] The embodiments of this application will now be described with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0043] Figure 2 is a schematic diagram of the structure of the first type of liquid crystal grating provided in the embodiment of this application. As shown in Figure 2, the liquid crystal grating 100 includes at least one liquid crystal grating unit 10. The liquid crystal grating unit 10 includes a liquid crystal cell 101 and a functional film layer 102 located on one side of the liquid crystal cell 101. The functional film layer 102 includes at least two functional sub-layers 1021 stacked together. Along the direction perpendicular to the plane where the functional film layer 102 is located, at least a portion of the edges of the at least two functional sub-layers 1021 are flush.

[0044] For example, functional sublayer 1021 can be understood as a half-wave plate. Functional film layer 102 includes at least two functional sublayers 1021 stacked together, that is, at least two functional sublayers 1021 are bonded together to form functional film layer 102. It is understood that the optical axis directions of at least two functional sublayers 1021 are different, so that incident light first enters the functional film layer 102 for polarization modulation, and the modulated light then enters the liquid crystal cell 101 to ensure that the modulated light matches the liquid crystal cell 101, thereby realizing the control of the light transmission direction by the liquid crystal grating 100.

[0045] For example, in this embodiment, at least a portion of the edges of at least two functional sub-layers 1021 are flush, which facilitates subsequent film fabrication, enhances edge impact resistance, and improves the reliability of the film edge. During the bonding process of the liquid crystal grating, at least two functional sub-layers 1021 are first bonded to form a functional film layer 102, and then the functional film layer 102 is bonded to the liquid crystal cell 101. This ensures that at least a portion of the edges of at least two functional sub-layers 1021 are flush, and bonding a single liquid crystal grating unit requires only one soft-to-hard bonding process, bonding the liquid crystal cell 101 to the functional film layer 102. For example, when the liquid crystal grating includes three liquid crystal grating units, the number of soft-to-hard bonding processes is three. Therefore, in this embodiment of the application, by first bonding the functional sublayer 1021 to form the functional film layer 102, and then bonding the functional film layer 102 to the liquid crystal cell 101, the number of bonding steps can be reduced, the bonding process of the liquid crystal grating can be simplified, the manufacturing difficulty can be reduced, and the number of stresses generated during the bonding process of the liquid crystal grating can be reduced, thus preventing the gate electrode from breaking due to the liquid crystal grating being subjected to multiple stresses during the bonding process.

[0046] The liquid crystal grating provided in this application embodiment has at least a portion of the edges of at least two functional sub-layers aligned along a direction perpendicular to the plane containing the functional film layer. This improves the reliability of the film layer edges, enhances edge impact resistance, reduces the probability of gate electrode breakage in the liquid crystal cell, and thus ensures the stability and reliability of the liquid crystal grating. Furthermore, it simplifies the manufacturing process and reduces fabrication difficulty. When bonding the liquid crystal grating, at least two functional sub-layers are first bonded to form the functional film layer, which is then bonded to the liquid crystal cell. This reduces the number of bonding operations on the liquid crystal grating, thereby reducing the stress generated during bonding and preventing gate electrode breakage due to repeated stress on the liquid crystal grating during bonding, thus contributing to the stability and reliability of the liquid crystal grating.

[0047] Optionally, referring to Figure 2, the functional film layer 102 is disposed on the light-incident side of the liquid crystal cell 101, where the arrows in the figure represent light rays, and the functional film layer 102 is configured to modulate the polarization state of the light rays incident on the liquid crystal cell 101.

[0048] For example, the functional film layer 102 is disposed on the light-incident side of the liquid crystal cell 101. That is, the incident light is first modulated by the functional film layer 102, and the modulated light is then incident on the liquid crystal cell 101. In other words, the incident light is modulated by the functional film layer 102 before being incident on the liquid crystal cell 101. This helps to ensure that the polarization state of the light modulated by the functional film layer 102 matches that of the liquid crystal cell 101, thereby realizing the control of the light transmission direction by the liquid crystal grating 100.

[0049] Figure 2 shows light incident from the light-incident side, which is on the side of the functional film layer 102 away from the liquid crystal cell 101, and is not shown in other figures.

[0050] Optionally, continuing to refer to Figure 2, at least two functional sublayers 1021 include a first half-wave plate 10211 and a second half-wave plate 10212, with the optical axis directions of the first half-wave plate 10211 and the second half-wave plate 10212 being different.

[0051] For example, the optical axis directions of the first half-wave plate 10211 and the second half-wave plate 10212 are different, which ensures that the light incident on the functional film layer 102 is modulated twice by polarization state. This helps to ensure that the polarization state of the light modulated by the functional film layer 102 matches the liquid crystal cell 101, thereby realizing the control of the light transmission direction by the liquid crystal grating 100.

[0052] For example, taking the direction perpendicular to the plane where the functional film layer 102 is located as 0 degrees (0°), the optical axis direction of the first half-wave plate 10211 can be 20°, and the optical axis direction of the second half-wave plate 10212 can be 60°. The first half-wave plate 10211 and the second half-wave plate 10212 can be first bonded together by a roll-to-roll process, and then the bonded film material is cut to form the functional film layer 102.

[0053] Optionally, referring to Figure 2, the liquid crystal grating 100 also includes a first adhesive layer 103, and the functional film layer 102 is attached to the light-incident side of the liquid crystal cell 101 through the first adhesive layer 103.

[0054] For example, the functional film layer 102 is attached to the light-incident side of the liquid crystal cell 101 by the first adhesive layer 103. That is, after the functional film layer 102 is prepared, it is attached to the light-incident side of the liquid crystal cell 101. In this way, the first adhesive layer 103 can fix the functional film layer 102 and the liquid crystal cell 101, and it is also beneficial to modulate the polarization state of the light incident on the liquid crystal cell 101 by the functional film layer 102.

[0055] For example, the material of the first adhesive layer 103 can be optical adhesive. The material of the first adhesive layer 103 in this embodiment can be set according to actual needs.

[0056] Optionally, referring to Figure 2, the liquid crystal grating 100 also includes a second adhesive layer 104, through which two adjacent functional sublayers 1021 are bonded together.

[0057] For example, two adjacent functional sublayers 1021 are bonded together by a second adhesive layer 104, and so on, after multiple functional sublayers 1021 are bonded together, a functional film layer 102 is formed.

[0058] For example, the material of the second adhesive layer 104 can be optical adhesive. In the embodiments of this application, the material of the second adhesive layer 104 can be set according to actual needs.

[0059] Optionally, referring to Figure 2, the functional film layer 102 is an integral structure, that is, multiple functional sublayers 1021 are bonded together to form a whole, i.e., the functional film layer 102 is an integral structure.

[0060] For example, in related technologies, the liquid crystal cell 101 is first bonded to one of the functional sublayers 1021 of the functional film layer 102, and then the bonded structure is bonded to another functional sublayer 1021. However, in the embodiments of this application, multiple functional sublayers 1021 are first bonded together to form a functional film layer 102, and then the functional film layer 102 is bonded to the liquid crystal cell 101. This reduces the number of bonding steps, thereby reducing the number of stresses generated during the bonding process of the liquid crystal grating, and preventing the gate electrode from breaking due to the liquid crystal grating being subjected to multiple stresses during the bonding process.

[0061] Optionally, Figure 3 is a schematic diagram of the structure of a second type of liquid crystal grating provided in the embodiment of this application. As shown in Figure 3, the liquid crystal grating 100 includes at least two stacked liquid crystal grating units 10, and the functional film layer 102 in each liquid crystal grating unit 10 is located on the light-incident side of the liquid crystal cell 101.

[0062] For example, the number of liquid crystal cells 101 corresponds to the number of functional film layers 102, that is, each liquid crystal cell 101 has a functional film layer 102 attached to its light-incident side. In other words, multiple functional film layers 102 can modulate the polarization state of the incident light multiple times, thereby ensuring the control of the light transmission direction by the liquid crystal grating.

[0063] For example, compared to the second liquid crystal grating unit 10-2, the first liquid crystal grating unit 10-1 is closer to the light incident side. Thus, the incident light first passes through the functional film layer 102 in the first liquid crystal grating unit 10-1 to adjust its polarization state before entering the liquid crystal cell 101 in the first liquid crystal grating unit 10-1. Then, it passes through the functional film layer 102 in the second liquid crystal grating unit 10-2 to adjust its polarization state before entering the liquid crystal cell 101 in the second liquid crystal grating unit 10-2. This enables the liquid crystal grating to control the direction of light transmission.

[0064] Optionally, continuing to refer to Figure 3, the edges of the functional sub-layers 1021 within the same liquid crystal grating unit 10 are aligned along a direction perpendicular to the plane where the functional film layer 102 is located.

[0065] For example, the edges of the functional sub-layers 1021 within the same liquid crystal grating unit 10 are aligned, that is, the upper edges of the functional sub-layers 1021 within the same liquid crystal grating unit 10 are located on the same horizontal line, and the lower edges are located on the same horizontal line.

[0066] The above embodiments can improve the reliability of the film edge, enhance the edge's resistance to impact, and reduce the probability of gate electrode breakage in the liquid crystal cell, thereby ensuring the stability and reliability of the liquid crystal grating; in addition, they can simplify the process and reduce the manufacturing difficulty.

[0067] Optionally, in this embodiment, the functional sub-layers 1021 in the liquid crystal grating unit 10 are first bonded to form a functional film layer 102, and then the functional film layer 102 is bonded to the liquid crystal cell 101. That is, at least two functional sub-layers 1021 in the first liquid crystal grating unit 10-1 are first bonded, and at least two functional sub-layers 1021 in the second liquid crystal grating unit 10-2 are bonded to form two functional film layers 102 respectively. Then, the two functional film layers 102 are bonded to the two liquid crystal cells 101 respectively to form the first liquid crystal grating unit. The first liquid crystal grating unit 10-1 and the second liquid crystal grating unit 10-2 are then bonded together to form a liquid crystal grating. This ensures that the edges of the functional sublayer 1021 in the first liquid crystal grating unit 10-1 and the functional sublayer 1021 in the second liquid crystal grating unit 10-2 are aligned. This reduces the number of bonding operations and simplifies the bonding process of the liquid crystal grating. It also reduces the probability of grid electrode breakage in the liquid crystal cell, thereby ensuring the stability and reliability of the liquid crystal grating (which will be discussed later).

[0068] Optionally, Figure 4 is a schematic diagram of the structure of the third type of liquid crystal grating provided in the embodiment of this application. As shown in Figure 4, along the direction perpendicular to the plane where the functional film layer 102 is located, the edges of the functional sub-layers 1021 in different liquid crystal grating units 10 are flush.

[0069] For example, the edges of the functional sub-layers 1021 in different liquid crystal grating units 10 are aligned, that is, the upper edges of all functional sub-layers 1021 in the liquid crystal grating are located on the same horizontal line, and the lower edges of all functional sub-layers 1021 are located on the same horizontal line.

[0070] For example, the edge of the functional sublayer 1021 in the first liquid crystal grating unit 10-1 is flush with the edge of the functional sublayer 1021 in the second liquid crystal grating unit 10-2. This reduces the probability of gate electrode breakage in the liquid crystal cell, thereby ensuring the stability and reliability of the liquid crystal grating. It also enables diverse designs for the liquid crystal grating. Furthermore, it improves the reliability of the film layer edges and enhances their resistance to impact.

[0071] In this embodiment, the edges of the functional sub-layers 1021 within different liquid crystal grating units 10 are aligned, that is, the edges of the functional film layers of different liquid crystal cells are aligned. In this way, for the liquid crystal cell sandwiched in the middle, the projection positions of the edges of the adjacent functional layers on both sides (one side is the functional film layer in its liquid crystal grating unit, and the other side is the functional film layer in another adjacent liquid crystal grating unit) are consistent. The stress positions of the edges on both sides are concentrated at the same position of the liquid crystal cell, and the compressive stress of the functional film layer edges on both sides of the liquid crystal cell can cancel each other out.

[0072] Optionally, continuing to refer to Figure 3, along the direction X from the light-incident side to the light-outceasing side of the liquid crystal grating, the projected areas of the functional film layers 102 in at least two liquid crystal grating units 10 on the plane where the liquid crystal cell 101 is located are different.

[0073] For example, the edges of the functional sub-layers 1021 within the same liquid crystal grating unit 10 are flush, while the edges of the functional sub-layers 1021 within different liquid crystal grating units 10 may not be flush.

[0074] For example, the projected area of ​​the functional film layer 102 in the first liquid crystal grating unit 10-1 on the plane where the liquid crystal cell 101 is located is smaller or larger than the projected area of ​​the functional film layer 102 in the second liquid crystal grating unit 10-2 on the plane where the liquid crystal cell 101 is located, thus enabling diversified designs of the liquid crystal grating.

[0075] This embodiment ensures that the aligned edges are only within a single liquid crystal grating unit, thus avoiding the alignment of the functional film layers of different liquid crystal cells. For a liquid crystal cell sandwiched in the middle, the projection positions of the edges of the adjacent functional layers on both sides (one side is the functional film layer within its liquid crystal grating unit, and the other side is the functional film layer within another adjacent liquid crystal grating unit) are consistent, and the stress positions of both edges are concentrated at the same location within the liquid crystal cell, preventing excessive stress differences between the edge areas exposed by the functional film layers and the areas covered by the functional film layers.

[0076] Optionally, Figure 5 is a schematic diagram of the structure of the fourth type of liquid crystal grating provided in the embodiment of this application, Figure 6 is a schematic diagram of the structure of the fifth type of liquid crystal grating provided in the embodiment of this application, Figure 7 is a schematic diagram of the structure of the sixth type of liquid crystal grating provided in the embodiment of this application, and Figure 8 is a schematic diagram of the structure of the seventh type of liquid crystal grating provided in the embodiment of this application. As shown in Figures 5-8, the liquid crystal grating 100 includes at least three stacked liquid crystal grating units 10. Along the direction from the light-incident side to the light-outceasing side of the liquid crystal grating (X direction as shown in the figure), the projected area of ​​the functional film layer 102 in different liquid crystal grating units 10 on the plane where the liquid crystal cell 101 is located increases sequentially, decreases sequentially, increases first and then decreases, or decreases first and then increases.

[0077] Referring again to Figures 5-8, taking a liquid crystal grating 100 comprising three stacked liquid crystal grating units 10 as an example, along the direction X from the light-incident side to the light-exit side, the liquid crystal grating 100 includes a first liquid crystal grating unit 10-1, a second liquid crystal grating unit 10-2, and a third liquid crystal grating unit 10-3. Each liquid crystal grating unit 10 includes a functional film layer 102 and a liquid crystal cell 101. Along the direction X from the light-incident side to the light-exit side, the functional film layers 102 are sequentially the first functional film layer 102-1, the second functional film layer 102-2, and the third functional film layer 102-3, and the liquid crystal cells 101 are sequentially the first liquid crystal cell 101-1, the second liquid crystal cell 101-2, and the third liquid crystal cell 101-3.

[0078] As a feasible implementation, continuing to refer to FIG5, along the direction X from the light-incident side to the light-outceasing side of the liquid crystal grating, the projected areas of the functional film layers 102 in different liquid crystal grating units 10 on the plane where the liquid crystal cell 101 is located increase sequentially. That is, the projected area of ​​the first functional film layer 102-1 on the plane where the first liquid crystal cell 101-1 is located is smaller than the projected area of ​​the second functional film layer 102-2 on the plane where the second liquid crystal cell 101-2 is located, and the projected area of ​​the second functional film layer 102-2 on the plane where the second liquid crystal cell 101-2 is located is smaller than the projected area of ​​the third functional film layer 102-3 on the plane where the third liquid crystal cell 101-3 is located.

[0079] As another feasible implementation, continuing to refer to FIG6, along the direction X from the light-incident side to the light-outceasing side of the liquid crystal grating, the projected areas of the functional film layers 102 in different liquid crystal grating units 10 on the plane where the liquid crystal cell 101 is located decrease sequentially. That is, the projected area of ​​the first functional film layer 102-1 on the plane where the first liquid crystal cell 101-1 is located is greater than the projected area of ​​the second functional film layer 102-2 on the plane where the second liquid crystal cell 101-2 is located, and the projected area of ​​the second functional film layer 102-2 on the plane where the second liquid crystal cell 101-2 is located is greater than the projected area of ​​the third functional film layer 102-3 on the plane where the third liquid crystal cell 101-3 is located.

[0080] As another feasible implementation, continuing to refer to FIG7, along the direction X from the light-incident side to the light-outceasing side of the liquid crystal grating, the projected area of ​​the functional film layer 102 in different liquid crystal grating units 10 on the plane where the liquid crystal cell 101 is located first increases and then decreases. That is, the projected area of ​​the first functional film layer 102-1 on the plane where the first liquid crystal cell 101-1 is located is smaller than the projected area of ​​the second functional film layer 102-2 on the plane where the second liquid crystal cell 101-2 is located, and is larger than the projected area of ​​the third functional film layer 102-3 on the plane where the third liquid crystal cell 101-3 is located.

[0081] As another feasible implementation, continuing to refer to FIG8, along the direction X from the light-incident side to the light-outceasing side of the liquid crystal grating, the projected area of ​​the functional film layer 102 in different liquid crystal grating units 10 on the plane where the liquid crystal cell 101 is located first decreases and then increases. That is, the projected area of ​​the first functional film layer 102-1 on the plane where the first liquid crystal cell 101-1 is located is greater than the projected area of ​​the second functional film layer 102-2 on the plane where the second liquid crystal cell 101-2 is located, and is smaller than the projected area of ​​the third functional film layer 102-3 on the plane where the third liquid crystal cell 101-3 is located. In this way, while reducing the probability of grid electrode breakage in the liquid crystal cell, diversified design of the liquid crystal grating can be achieved.

[0082] Optionally, referring to Figure 3, the liquid crystal grating 100 also includes a third adhesive layer 105, through which the functional film layer 102 is bonded to the liquid crystal cell 101 in the adjacent liquid crystal grating unit 10.

[0083] For example, the functional film layer 102 in the second liquid crystal grating unit 10-2 is bonded to the liquid crystal cell 101 in the first liquid crystal grating unit 10-1 by a third adhesive layer 105. Thus, the first liquid crystal grating unit 10-1 and the second liquid crystal grating unit 10-2 are bonded and fixed by the third adhesive layer 105 to form a liquid crystal grating 100.

[0084] For example, the material of the third adhesive layer 105 can be optical adhesive, and the material of the third adhesive layer 105 in this embodiment can be set according to actual needs.

[0085] Optionally, referring to Figures 3 and 4, in Figure 3, the projection of the third adhesive layer 105 onto the plane of the liquid crystal cell 101 is smaller than the projection of the adjacent functional film layer 102 onto the plane of the liquid crystal cell 101. In Figure 4, the projection of the third adhesive layer 105 onto the plane of the liquid crystal cell 101 is larger than the projection of the adjacent functional film layer 102 onto the plane of the liquid crystal cell 101.

[0086] For example, taking a liquid crystal grating 100 including a first liquid crystal grating unit 10-1 and a second liquid crystal grating unit 10-2 as an example, a first half-wave plate 10211 and a corresponding second half-wave plate 10212 are bonded together using a second adhesive layer 104 to form two functional film layers 102, namely, a first functional film layer 102-1 and a second functional film layer 102-2. Then, the first functional film layer 102-1 is bonded to the light-incident surface of the first liquid crystal cell 101-1, a third adhesive layer 105 is bonded to the light-emitting surface of the first liquid crystal cell 101-1, and the second functional film layer 102-2 is bonded to the light-incident surface of the second liquid crystal cell 101-2. Finally, the first liquid crystal grating unit 10-1 and the second liquid crystal grating unit 10-2 are bonded together using the third adhesive layer 105 to form the liquid crystal grating 100.

[0087] In some embodiments, after the third adhesive layer 105 is bonded to the light-emitting side surface of the first liquid crystal cell 101-1, the first liquid crystal grating unit 10-1 and the second functional film layer 102-2 in the second liquid crystal grating unit 10-2 are bonded through the third adhesive layer 105. Due to bonding process errors, the edge of the third adhesive layer 105 may not be flush with the edge of the adjacent functional film layer 102. That is, the projection of the third adhesive layer 105 on the plane of the liquid crystal cell 101 is greater than or less than the projection of the adjacent functional film layer 102 on the plane of the liquid crystal cell 101.

[0088] In other embodiments, the projection of the third adhesive layer 105 onto the plane of the liquid crystal cell 101 may be equal to the projection of the adjacent functional film layer 102 onto the plane of the liquid crystal cell 101.

[0089] Optionally, Figure 9 is a schematic diagram of the structure of the eighth type of liquid crystal grating provided in the embodiment of this application. As shown in Figure 9, the projection of the third adhesive layer 105 on the plane where the liquid crystal cell 101 is located coincides with the projection of the adjacent functional film layer 102 on the plane where the liquid crystal cell 101 is located.

[0090] For example, the projection of the third adhesive layer 105 onto the plane of the liquid crystal cell 101 is made to coincide with the projection of the adjacent functional film layer 102 onto the plane of the liquid crystal cell 101. This can improve the reliability of the film layer edge and enhance the edge's resistance to impact.

[0091] For example, the projection of the third adhesive layer 105 onto the plane of the liquid crystal cell 101 coincides with the projection of the adjacent functional film layer 102 onto the plane of the liquid crystal cell 101. In other words, the projection area of ​​the third adhesive layer 105 onto the plane of the liquid crystal cell 101 is equal to the projection area of ​​the adjacent functional film layer 102 onto the plane of the liquid crystal cell 101. That is, the first half-wave plate 10211 and the corresponding second half-wave plate 10212 are bonded together by the second adhesive layer 104 to form the first functional film layer 102-1. By bonding the third adhesive layer 105, the second first half-wave plate 10211, and the corresponding second half-wave plate 10212 together, the second functional film layer 102-2 can be formed. This ensures that the edge of the third adhesive layer 105 is flush with the edge of the second functional film layer 102-2. Then, the first functional film layer 102-1 is bonded to the light-incident surface of the first liquid crystal cell 101-1 to form the first liquid crystal grating unit 10-1. The second functional film layer 102-2 is bonded to the light-incident surface of the second liquid crystal cell 101-2 to form the second liquid crystal grating unit 10-2. Finally, the first liquid crystal grating unit 10-1 and the second liquid crystal grating unit 10-2 are bonded together with the third adhesive layer 105 to form the liquid crystal grating 100. In this way, the probability of grid electrode breakage in the liquid crystal cell can be reduced, and diversified designs of the liquid crystal grating can be achieved.

[0092] Optionally, Figure 10 is a schematic diagram of the structure of a liquid crystal cell in a liquid crystal grating provided in an embodiment of this application. As shown in Figure 10, the liquid crystal cell 101 includes a first substrate 1011, a second substrate 1012 disposed opposite to each other, and a liquid crystal layer 1013 located between the first substrate 1011 and the second substrate 1012; the liquid crystal grating includes at least two stacked liquid crystal grating units, in at least one liquid crystal grating unit the first substrate 1011 of the liquid crystal cell 101 is located on the light-incident side, and in at least one liquid crystal grating unit the first substrate 1011 of the liquid crystal cell 101 is located on the light-emitting side.

[0093] For example, the first substrate 1011 and the second substrate 1012 may be glass substrates for protecting the film structure within the liquid crystal cell 101. The liquid crystal layer 1013 between the first substrate 1011 and the second substrate 1012 includes liquid crystal molecules. A plurality of support structures 1014 are disposed between the first substrate 1011 and the second substrate 1012 to support the first substrate 1011 and the second substrate 1012, thereby forming the filling space of the liquid crystal layer 1013. For example, the shape of the support structure 1014 may be columnar or strip-shaped (e.g., a barrier wall). In this embodiment, the shape of the support structure 1014 is a frustum, and for example, the cross-sectional view of the support structure 1014 is an inverted trapezoid.

[0094] In some embodiments, as shown in FIG10, a driving electrode layer 1015 is provided between the first substrate 1011 and the second substrate 1012.

[0095] For example, the driving electrode layer 1015 includes multiple gate electrodes 10151, which can be independently set. The side of the second substrate 1012 near the support structure 1014 includes a common electrode layer 1016, which can be a common electrode set on the entire surface. There is a voltage difference between the common electrode and the gate electrode 10151. Thus, the longitudinal electric field formed by the common electrode and the gate electrode 10151 can drive the liquid crystal molecules in the liquid crystal layer 1013 to rotate, thereby refracting the light incident on the liquid crystal cell 101.

[0096] For example, since the driving electrode layer 1015 is located on the side close to the first substrate 1011, the first substrate 1011 of the liquid crystal cell 101 in at least one liquid crystal grating unit is located on the light-incident side, and the first substrate 1011 of the liquid crystal cell 101 in at least one liquid crystal grating unit is located on the light-emitting side. Taking the liquid crystal grating 100 including a first liquid crystal grating unit 10-1 and a second liquid crystal grating unit 10-2 as an example, the first substrate 1011 of the liquid crystal cell 101 in the first liquid crystal grating unit 10-1 is located on the light-incident side, and the first substrate 1011 of the liquid crystal cell 101 in the second liquid crystal grating unit 10-2 is located on the light-emitting side. In this way, the control of the light transmission direction by the liquid crystal grating can be realized.

[0097] For example, the first substrate 1011 may also include an auxiliary structure 1017, at least a portion of which is located between at least a portion of the gate electrode 10151 and the support structure 1014. That is, by setting the auxiliary structure 1017, the thickness of the inorganic layer between the support structure 1014 and the first substrate 1011 can be increased, thereby improving the compressive strength of the liquid crystal cell 101. Thus, during the fabrication or use of the liquid crystal grating, when the support structure 1014 is subjected to external pressure, the gate electrode 10151 will not break, which helps to ensure the stability of the liquid crystal grating.

[0098] In some embodiments, the gate electrode 10151 overlaps with at most one support structure 1014 in the direction from the first substrate 1011 to the second substrate 1012, thereby reducing the probability of the gate electrode 10151 breaking during the liquid crystal grating bonding process.

[0099] For example, the auxiliary structure 1017 may be at least one of an insulating layer and a driving electrode layer. In one feasible embodiment, the auxiliary structure 1017 may be an insulating layer, that is, the structure between the first substrate 1011 and the support structure 1014 is an "insulating layer-driving electrode layer-insulating layer". As another feasible embodiment, the auxiliary structure 1017 may be a driving electrode layer, that is, the structure between the first substrate 1011 and the support structure 1014 is an "insulating layer-driving electrode layer-insulating layer-driving electrode layer". As yet another feasible embodiment, the auxiliary structure 1017 may be an insulating layer and a driving electrode layer, that is, the structure between the first substrate 1011 and the support structure 1014 is an "insulating layer-driving electrode layer-insulating layer-driving electrode layer-insulating layer". This can improve the compressive strength of the liquid crystal grating, ensure the stability and reliability of the liquid crystal grating, and enable diversified designs of the liquid crystal grating.

[0100] For example, the side of the first substrate 1011 near the second substrate 1012 and the side of the second substrate 1012 near the first substrate 1011 may also include a dielectric layer. By providing a dielectric layer, the liquid crystal cell 101 can be protected from damage by the external environment, and the charge between the electrodes can be effectively isolated to prevent charge leakage and arcing, thus ensuring that the liquid crystal cell 101 can work normally.

[0101] For example, the side of the second substrate 1012 near the support structure 1014 includes a light-shielding layer 1018 and a common electrode layer 1016; the projection of the light-shielding layer 1018 onto the first substrate 1011 covers the projection of the support structure 1014 onto the first substrate 1011; the common electrode layer 1016 includes a common electrode disposed throughout the entire layer.

[0102] Exemplarily, the liquid crystal cell 101 further includes a first insulating layer 1019 located between the driving electrode layer 1015 and the first substrate 1011. The first insulating layer 1019 can be understood as a first passivation layer. The setting of the first insulating layer 1019 is beneficial to improving the uniformity of the driving electrode layer 1015 and avoiding defects in the driving electrode layer 1015. The auxiliary structure 1017 can be understood as a second passivation layer. That is, the structure between the first substrate 1011 and the support structure 1014 can be an "insulating layer - driving electrode layer - insulating layer" structure. In this way, by setting an insulating layer between the gate electrode 10151 and the support structure 1014 and an insulating layer between the first substrate 1011 and the gate electrode 10151, the thickness of the inorganic layer can be increased, the compressive resistance of the liquid crystal cell 101 can be improved, the support structure 1014 can be prevented from directly contacting the gate electrode 10151, and the gate electrode 10151 can be prevented from directly contacting the first substrate 1011. That is, insulating layers are provided on both the upper and lower sides of the gate electrode 10151, which can achieve a good buffering effect. Furthermore, when the support structure 1014 is subjected to external pressure, the support structure 1014 can be prevented from squeezing or rubbing the gate electrode 10151, thereby avoiding the problem that the gate electrode 10151 is broken and affecting the performance of the liquid crystal grating.

[0103] Optionally, continuing to refer to FIG. 3, the liquid crystal grating includes n liquid crystal grating units 10 bonded by n - 1 adhesive layers. The liquid crystal grating unit 10 includes a liquid crystal cell 101, a first half-wave plate 10211, and a second half-wave plate 10212 located on the incident light side of the liquid crystal cell 101. The order of the liquid crystal grating units 10 on the incident light side is 1, and the order of the liquid crystal grating units 10 on the outgoing light side is n, where n is an integer greater than or equal to 2. The first half-wave plate 10211 and the corresponding second half-wave plate 10212 are bonded to form n functional film layers 102. The i-th functional film layer 102 is bonded to the incident light side surface of the i-th liquid crystal cell 101, the i-th adhesive layer is bonded to the outgoing light side surface of the i-th liquid crystal cell 101, and the n-th functional film layer 102 is bonded to the incident light side surface of the n-th liquid crystal cell 101 to form n liquid crystal grating units 10. The n liquid crystal grating units 1 ten are bonded to form a liquid crystal grating 100. Here, i < n and i is a positive integer.

[0104] Referring again to Figure 3, the description will be based on an example where the liquid crystal grating 100 includes two liquid crystal grating units 10. For instance, i = 1, n = 2. The liquid crystal grating 100 includes two liquid crystal grating units 10 bonded together by a single adhesive layer, namely, a first liquid crystal grating unit 10-1 and a second liquid crystal grating unit 10-2. Each liquid crystal grating unit 10 includes a liquid crystal cell 101 and a first half-wave plate 10211 and a second half-wave plate 10212 located on the light-incident side of the liquid crystal cell 101. The order of the liquid crystal grating units 10 on the light-incident side is 1, and the order of the liquid crystal grating units 10 on the light-exit side is 2. The first functional film layer 10211 and the corresponding second half-wave film 10212 are bonded together to form two functional film layers 102. The first functional film layer 102 is bonded to the light-incident surface of the first liquid crystal cell 101, the first adhesive layer is bonded to the light-emitting surface of the first liquid crystal cell 101, and the second functional film layer 102 is bonded to the light-incident surface of the second liquid crystal cell 101 to form two liquid crystal grating units 10. The two liquid crystal grating units 10 are bonded together to form a liquid crystal grating 100. This reduces the number of times the liquid crystal grating is bonded, reduces the probability of grid electrode breakage in the liquid crystal cell, and improves the stability and reliability of the liquid crystal grating.

[0105] In summary, the liquid crystal grating provided in this application embodiment has at least two functional sub-layers with at least a portion of their edges flush along a direction perpendicular to the plane where the functional film layer is located. The at least two functional sub-layers are first bonded together to form a functional film layer, and then the functional film layer is bonded to the liquid crystal cell. This reduces the number of bonding times of the liquid crystal grating, thereby reducing the number of stresses generated during the bonding process of the liquid crystal grating. This prevents the gate electrode from breaking due to the liquid crystal grating being subjected to multiple stresses during the bonding process, thus helping to ensure the stability and reliability of the liquid crystal grating.

[0106] This application embodiment also provides a method for bonding a liquid crystal grating. Figure 11 is a process flow diagram of the first method for bonding a liquid crystal grating provided in this application embodiment, and Figure 12 is a structural schematic diagram corresponding to the bonding process of the first method for bonding a liquid crystal grating provided in this application embodiment. As shown in Figures 11 and 12, the liquid crystal grating includes at least one liquid crystal grating unit 10. The liquid crystal grating unit 10 includes a liquid crystal cell 101 and a functional film layer 102 located on one side of the liquid crystal cell 101. The functional film layer 102 includes at least two functional sub-layers 1021 stacked together. The method for bonding the liquid crystal grating includes:

[0107] S101 provides at least two functional sublayers and a liquid crystal cell.

[0108] For example, at least two functional sublayers 1021 include a first half-wave plate 10211 and a second half-wave plate 10212.

[0109] For example, the first half-wave plate 10211 and the second half-wave plate 10212 can be first bonded together using a roll-to-roll process, and then the bonded film material can be cut to form the functional film layer 102. Figure 13 is a structural schematic diagram of the bonding process of the first half-wave plate and the second half-wave plate provided in this embodiment of the application. As shown in Figure 13, step S1 corresponds to providing the first half-wave plate 10211 and the second half-wave plate 10212. For example, with the direction perpendicular to the plane where the functional film layer 102 is located as 0°, the optical axis direction of the first half-wave plate 10211 can be 20°, and the optical axis direction of the second half-wave plate 10212 can be 60°. Step S2 corresponds to bonding the first half-wave plate 10211 and the second half-wave plate 10212 together using a roll-to-roll process. For example, laser and optical adhesive are used to bond the first half-wave plate 10211 and the second half-wave plate 10212 together using a roll-to-roll process. Step S3 corresponds to cutting the laminated film material. For example, the laminated film material is cut along the cutting line M, so that the edges of the first half-wave plate 10211 and the second half-wave plate 10212 are flush, thereby improving the reliability of the film edge and enhancing the edge's resistance to impact when laminated to the liquid crystal cell. For example, the optical axis directions of the first half-wave plate 10211 and the second half-wave plate 10212 are different, ensuring that the light incident on the functional film layer 102 undergoes two polarization modulations. This helps ensure that the polarization state of the light modulated by the functional film layer 102 matches the liquid crystal cell, thereby enabling the liquid crystal grating to control the light transmission direction.

[0110] For example, continuing to refer to FIG10, the liquid crystal cell 101 may include a first substrate 1011, a second substrate 1012 and a liquid crystal layer 1013 located between the first substrate 1011 and the second substrate 1012.

[0111] Optionally, the first half-wave plate 10211 and the second half-wave plate 10212 are bonded together with optically clear adhesive (OCA).

[0112] Optionally, the laminated film can be cut using a laser.

[0113] Step S101 in Figure 12 is the structural schematic diagram corresponding to step S101 in Figure 11, that is, the structural schematic diagram corresponds one-to-one with the steps in the process flow diagram.

[0114] S102. At least two functional sublayers are bonded together to form a functional film layer.

[0115] For example, at least two functional sublayers 1021 are bonded together by a second adhesive layer 104 to form a functional film layer 102.

[0116] S103. The functional film layer is attached to one side of the liquid crystal cell to form a liquid crystal grating unit.

[0117] For example, the functional film layer 102 is bonded to one side of the liquid crystal cell 101 through the first adhesive layer 103 to form a liquid crystal grating unit 10.

[0118] Figure 14 is a schematic diagram of the bonding process of a liquid crystal grating bonding method. As shown in Figure 14, the liquid crystal cell 101' is first bonded to one of the functional sublayers 1021' in the functional film layer, and then the bonded structure is bonded to another functional sublayer 1021', thus forming a liquid crystal grating unit. Each thin dashed box in Figure 14 represents a soft-to-hard bonding process (functional film layer bonded to glass), and each thick dashed box represents a hard-to-soft bonding process (glass bonded to functional film layer). For example, when the liquid crystal grating includes three liquid crystal grating units, a total of 8 soft-to-hard bonding processes and 2 hard-to-soft bonding processes are required, resulting in a large number of bonding operations and a complex bonding process. However, the embodiments of this application directly bond the bonded functional film layer to the liquid crystal cell, thereby reducing at least one soft-to-hard bonding process in the bonding process of a single liquid crystal grating unit compared to related technologies. Furthermore, the bonding method provided in this application embodiment is advantageous for designing different sizes of the third adhesive layer when bonding multiple liquid crystal grating units. That is, in related technologies, the third adhesive layer can never be flush with the edge of its adjacent functional film layer. However, in this application embodiment, the projection of the third adhesive layer on the plane where the liquid crystal cell is located can coincide with the projection of the adjacent functional film layer on the plane where the liquid crystal cell is located. This can improve the reliability of the film layer edge and enhance the edge's resistance to collisions.

[0119] The liquid crystal grating bonding method provided in this application first bonds multiple functional sublayers together to form a functional film layer, and then bonds the functional film layer to the liquid crystal cell. Compared with related technologies that first bond the liquid crystal cell to one functional sublayer of the functional film layer, and then bond the bonded structure to another functional sublayer, this application reduces the number of bonding steps, thereby reducing the stress generated during the bonding process of the liquid crystal grating. This prevents the gate electrode from breaking due to repeated stress on the liquid crystal grating during bonding, thus ensuring the stability and reliability of the liquid crystal grating. It is understood that both soft-to-hard and hard-to-soft bonding processes can cause the gate electrode inside the liquid crystal cell to break under pressure, affecting the performance of the liquid crystal grating. This application significantly reduces the number of bonding steps, which greatly improves the yield of the liquid crystal grating.

[0120] Optionally, Figure 15 is a process flow diagram of the second liquid crystal grating bonding method provided in the embodiments of this application, and Figure 16 is a structural schematic diagram corresponding to the bonding process of the second liquid crystal grating bonding method provided in the embodiments of this application. Based on the above embodiments, Figures 15 and 16 illustrate the operation after the functional film layer is bonded to one side of the liquid crystal cell to form the liquid crystal grating unit, where the liquid crystal grating includes at least two liquid crystal grating units. As shown in Figures 15 and 16, the liquid crystal grating bonding method includes:

[0121] S201, providing at least two functional sublayers and at least one liquid crystal cell.

[0122] Taking a liquid crystal grating comprising two liquid crystal grating units 10 as an example, four functional sub-layers 1021 and two liquid crystal cells 101 are provided. The four functional sub-layers 1021 include two first half-wave plates 10211 and two second half-wave plates 10212.

[0123] S202. At least two functional sublayers are bonded together to form a functional film layer.

[0124] For example, two functional sub-layers 1021 are bonded together by a second adhesive layer 104 to form two functional film layers 102, namely a first functional film layer 102-1 and a second functional film layer 102-2.

[0125] S203. The functional film layer is attached to one side of the liquid crystal cell to form a liquid crystal grating unit.

[0126] For example, a first functional film layer 102-1 is bonded to one side of a first liquid crystal cell 101-1 via a first adhesive layer 103 to form a first liquid crystal grating unit 10-1. A second functional film layer 102-2 is bonded to one side of a second liquid crystal cell 101-2 via a first adhesive layer 103 to form a second liquid crystal grating unit 10-2.

[0127] S204. At least two liquid crystal grating units are sequentially stacked and bonded together to form a liquid crystal grating.

[0128] For example, the first liquid crystal grating unit 10-1 and the second liquid crystal grating unit 10-2 are bonded together by the third adhesive layer 105 to form a liquid crystal grating.

[0129] Referring again to Figure 10, the first substrate 1011 of the liquid crystal cell 101 in at least one liquid crystal grating unit 10 is located on the light-incident side, and the first substrate 1011 of the liquid crystal cell 101 in at least one liquid crystal grating unit 10 is located on the light-emitting side, thus ensuring that the liquid crystal grating works normally.

[0130] The liquid crystal grating bonding method provided in this application embodiment involves bonding multiple functional sublayers together to form a functional film layer when the liquid crystal grating includes multiple liquid crystal grating units. Then, the functional film layer is bonded to the liquid crystal cell to form a liquid crystal grating unit. Finally, the liquid crystal grating units are sequentially stacked and bonded to form the liquid crystal grating. This reduces the number of bonding steps, thereby reducing the stress generated during the bonding process of the liquid crystal grating. This prevents the gate electrode from breaking due to repeated stress on the liquid crystal grating during the bonding process, thus ensuring the stability and reliability of the liquid crystal grating.

[0131] Optionally, Figure 17 is a process flow diagram of the third liquid crystal grating bonding method provided in the embodiments of this application, and Figure 18 is a structural schematic diagram corresponding to the bonding process of the third liquid crystal grating bonding method provided in the embodiments of this application. Figures 17 and 18, based on the above embodiments, illustrate the technical solution of the liquid crystal grating including n liquid crystal grating units. As shown in Figures 17 and 18, the bonding method of the liquid crystal grating includes:

[0132] S301 provides n first half-wave plates, n second half-wave plates, n liquid crystal cells, and n-1 adhesive layers.

[0133] Taking a liquid crystal grating comprising three liquid crystal grating units as an example, i.e., n=3. For example, three first half-wave plates, three second half-wave plates, three liquid crystal cells, and two adhesive layers are provided, the adhesive layer being a third adhesive layer 105. The liquid crystal grating includes three liquid crystal grating units 10 bonded together by the two adhesive layers. Each liquid crystal grating unit 10 includes a liquid crystal cell 101 and a first half-wave plate 10211 and a second half-wave plate 10212 located on the light-incident side of the liquid crystal cell 101. The order of the liquid crystal grating units 10 on the light-incident side is 1, i.e., first liquid crystal grating unit 10-1, and the order of the liquid crystal grating units 10 on the light-exit side is 3, i.e., third liquid crystal grating unit 10-3.

[0134] S302. The first half-wave plate and the corresponding second half-wave plate are bonded together to form n functional film layers.

[0135] For example, the first half-wave plate 10211 and the corresponding second half-wave plate 10212 are bonded together by the second adhesive layer 104 to form three functional film layers 102, namely the first functional film layer 102-1, the second functional film layer 102-2 and the third functional film layer 102-3.

[0136] S303. The i-th functional film layer is bonded to the light-incident surface of the i-th liquid crystal cell, the i-th adhesive layer is bonded to the light-emitting surface of the i-th liquid crystal cell, and the n-th functional film layer is bonded to the light-incident surface of the n-th liquid crystal cell to form n liquid crystal grating units.

[0137] Exemplarily, when i = 1, the first functional film layer 102-1 is bonded to the light-incident side surface of the first liquid crystal cell 101-1, and the first third adhesive layer 105 is bonded to the light-exiting side surface of the first liquid crystal cell 101-1. When i = 2, the second functional film layer 102-2 is bonded to the light-incident side surface of the second liquid crystal cell 101-2, the second third adhesive layer 105 is bonded to the light-exiting side surface of the second liquid crystal cell 101-2, and the third functional film layer 102-3 is bonded to the light-incident side surface of the third liquid crystal cell 101-3, forming 3 liquid crystal grating units 10.

[0138] S304. Bond n liquid crystal grating units to form a liquid crystal grating.

[0139] Exemplarily, when i < n and i is a positive integer, bond the first liquid crystal grating unit 10-1, the second liquid crystal grating unit 10-2, and the third liquid crystal grating unit 10-3 through the third adhesive layer 105 to form a liquid crystal grating.

[0140] For the liquid crystal grating bonding method provided in the embodiments of the present application, when the liquid crystal grating includes n liquid crystal grating units, first bond multiple functional sub-layers to form n functional film layers, then bond the n functional film layers to n liquid crystal cells, bond the i-th functional film layer to the light-incident side surface of the i-th liquid crystal cell, the i-th adhesive layer to the light-exiting side surface of the i-th liquid crystal cell, and the n-th functional film layer to the light-incident side surface of the n-th liquid crystal cell to form n liquid crystal grating units, and finally stack and bond the liquid crystal grating units in sequence to form a liquid crystal grating. In this way, the number of bonding times can be reduced, and thus the number of stress times generated during the bonding process of the liquid crystal grating can be reduced, preventing the gate electrode from breaking due to the liquid crystal grating being stressed multiple times during the bonding process, and further ensuring the stability and reliability of the liquid crystal grating.

[0141] Optionally, FIG. 19 is a process flow chart of the fourth liquid crystal grating bonding method provided in the embodiments of the present application, and FIG. 20 is a schematic structural diagram corresponding to the bonding process of the fourth liquid crystal grating bonding method provided in the embodiments of the present application. As shown in FIGS. 19 and 20, the liquid crystal grating bonding method includes:

[0142] S401. Provide n first half-wave plates, n second half-wave plates, n liquid crystal cells, and n - 1 adhesive layers.

[0143] Taking the example that the liquid crystal grating includes three liquid crystal grating units, i.e., n = 3. Exemplarily, 3 first half-wave plates, 3 second half-wave plates, 3 liquid crystal cells, and 2 adhesive layers are provided, and the adhesive layer is the third adhesive layer 105. The liquid crystal grating includes 3 liquid crystal grating units bonded by 2 adhesive layers. Each liquid crystal grating unit 10 includes a liquid crystal cell 101 and a first half-wave plate 10211 and a second half-wave plate 10212 located on the incident light side of the liquid crystal cell 101. The order of the liquid crystal grating units 10 on the incident light side is 1, i.e., the first liquid crystal grating unit 10-1, and the order of the liquid crystal grating units 10 on the outgoing light side is 3, i.e., the third liquid crystal grating unit 10-3.

[0144] S402. Bond the first first half-wave plate and the corresponding second half-wave plate, and bond the j-th adhesive layer, the (j + 1)-th first half-wave plate and the corresponding second half-wave plate to form n functional film layers.

[0145] Exemplarily, bond the first half-wave plate 10211 and the corresponding second half-wave plate 10212 through the second adhesive layer 104 to form the first functional film layer 102-1. When j = 1, bond the first adhesive layer, the second first half-wave plate 10211 and the corresponding second half-wave plate 10212 to form the second functional film layer 102-2. When j = 2, bond the second adhesive layer, the third first half-wave plate 10211 and the corresponding second half-wave plate 10212 to form the third functional film layer 102-3. In this way, it can be ensured that the edge of the third adhesive layer 105 is flush with the edge of the adjacent functional film layer 102.

[0146] S403. Bond the first functional film layer to the incident light side surface of the first liquid crystal cell, and bond the k-th functional film layer to the incident light side surface of the k-th liquid crystal cell to form n liquid crystal grating units.

[0147] Exemplarily, bond the first functional film layer 102-1 to the incident light side surface of the first liquid crystal cell 101-1 to form the first liquid crystal grating unit 10-1, bond the second functional film layer 102-2 to the incident light side surface of the second liquid crystal cell 101-2 to form the second liquid crystal grating unit 10-2, and bond the third functional film layer 102-3 to the incident light side surface of the third liquid crystal cell 101-3 to form the third liquid crystal grating unit 10-3.

[0148] S404. Bond n liquid crystal grating units to form a liquid crystal grating.

[0149] Exemplarily, j < n, 1 < k ≤ n, and both j and k are positive integers. Bond the first liquid crystal grating unit 10-1, the second liquid crystal grating unit 10-2, and the third liquid crystal grating unit 10-3 through the third adhesive layer 105 to form a liquid crystal grating.

[0150] The liquid crystal grating bonding method provided in this application embodiment, when the liquid crystal grating includes n liquid crystal grating units, firstly, the first half-wave plate and the corresponding second half-wave plate are bonded together, and the j-th adhesive layer, the (j+1)-th first half-wave plate and the corresponding second half-wave plate are bonded together to form n functional film layers. Then, the first functional film layer is bonded to the light-incident surface of the first liquid crystal cell, and the k-th functional film layer is bonded to the light-incident surface of the k-th liquid crystal cell to form n liquid crystal grating units. Finally, the liquid crystal grating units are sequentially stacked and bonded to form the liquid crystal grating. This reduces the number of bonding steps, thereby reducing the number of stresses generated during the bonding process of the liquid crystal grating, preventing the gate electrode from breaking due to repeated stress on the liquid crystal grating during the bonding process, and thus ensuring the stability and reliability of the liquid crystal grating.

[0151] This application also provides a three-dimensional display device. Figure 21 is a structural schematic diagram of a three-dimensional display device provided in this application. As shown in Figure 21, the three-dimensional display device includes a backlight module 200, a spatial light modulator 300, a converging field lens 400, and a liquid crystal grating 100 in the above embodiment, which are stacked sequentially. The backlight module 200 is configured to provide field-sequence collimated coherent backlight required for display. The spatial light modulator 300 is configured to modulate the phase and amplitude of the field-sequence collimated coherent backlight. The converging field lens 400 is configured to converge the modulated field-sequence collimated coherent backlight onto the liquid crystal grating 100. The liquid crystal grating 100 is configured to transmit the left-eye image and the right-eye image in the three-dimensional optical image to the human eye.

[0152] For example, the field-sequential collimated coherent backlight provided by the backlight module 200 is modulated by the spatial light modulator 300 using at least one of the following: phase modulation and amplitude modulation. The modulated field-sequential collimated coherent backlight is then focused by the converging field lens 400 onto the viewing window at the human eye position, allowing the human eye to see the image displayed by the display device. In other words, the converging field lens 400 can direct the light modulated by the spatial light modulator 300 onto the liquid crystal grating 100, thereby forming a left-eye image and a right-eye image.

[0153] The three-dimensional display device provided in this application embodiment can reduce the number of times the liquid crystal grating is bonded, reduce the probability of grid electrode breakage in the liquid crystal cell, and improve the stability and reliability of the liquid crystal grating.

Claims

1. A liquid crystal grating comprising at least one liquid crystal grating unit, the liquid crystal grating unit comprising a liquid crystal cell and a functional film layer located on one side of the liquid crystal cell; the functional film layer comprising at least two functional sub-layers stacked together, at least part of the edges of the at least two functional sub-layers being flush in a direction perpendicular to the plane of the functional film layer.

2. The liquid crystal grating of claim 1, wherein, the functional film layer is located on the light-incoming side of the liquid crystal cell, and is configured to modulate the polarization state of light incident on the liquid crystal cell.

3. The liquid crystal grating of claim 2, wherein, the at least two functional sub-layers comprise a first half-wave plate and a second half-wave plate, the optical axis direction of the first half-wave plate being different from the optical axis direction of the second half-wave plate. 4.The liquid crystal grating of claim 1, further comprising a first adhesive layer, the functional film layer being attached to the light-incoming side of the liquid crystal cell via the first adhesive layer. 5.The liquid crystal grating of claim 1, further comprising a second adhesive layer, two adjacent functional sub-layers being attached via the second adhesive layer.

6. The liquid crystal grating of claim 1, wherein, the functional film layer is of an integrated structure.

7. The liquid crystal grating of claim 1, wherein, the liquid crystal grating comprises at least two liquid crystal grating units stacked together, the functional film layer in each of the liquid crystal grating units being located on the light-incoming side of the liquid crystal cell.

8. The liquid crystal grating of claim 7, wherein, the edges of the functional sub-layers in the same liquid crystal grating unit are flush in a direction perpendicular to the plane of the functional film layer.

9. The liquid crystal grating of claim 7, wherein, the edges of the functional sub-layers in different liquid crystal grating units are flush in a direction perpendicular to the plane of the functional film layer.

10. The liquid crystal grating of claim 8, wherein, the projection areas of the functional film layers in the at least two liquid crystal grating units on the plane of the liquid crystal cell are different in a direction from the light-incoming side to the light-outgoing side of the liquid crystal grating.

11. The liquid crystal grating of claim 8, wherein, the liquid crystal grating comprises at least three liquid crystal grating units stacked together, the projection areas of the functional film layers in the different liquid crystal grating units on the plane of the liquid crystal cell being sequentially increased, sequentially decreased, first increased and then decreased, or first decreased and then increased in a direction from the light-incoming side to the light-outgoing side of the liquid crystal grating. 12.The liquid crystal grating of claim 7, further comprising a third adhesive layer, the functional film layer being attached to the liquid crystal cell in the adjacent liquid crystal grating unit via the third adhesive layer.

13. The liquid crystal grating of claim 12, wherein, the projection of the third adhesive layer on the plane of the liquid crystal cell is larger or smaller than the projection of the adjacent functional film layer on the plane of the liquid crystal cell.

14. The liquid crystal grating of claim 12, wherein, the projection of the third adhesive layer on the plane of the liquid crystal cell coincides with the projection of the adjacent functional film layer on the plane of the liquid crystal cell.

15. The liquid crystal grating of claim 1, wherein, the liquid crystal cell comprises a first substrate, a second substrate and a liquid crystal layer located between the first substrate and the second substrate; the liquid crystal grating comprises at least two liquid crystal grating units stacked together, the first substrate of the liquid crystal cell in at least one of the liquid crystal grating units being located on the light-incoming side, and the first substrate of the liquid crystal cell in at least one of the liquid crystal grating units being located on the light-outgoing side.

16. The liquid crystal grating of claim 1, wherein, The liquid crystal grating comprises n liquid crystal grating units laminated by n-1 adhesive layers, each of the liquid crystal grating units comprises a liquid crystal cell and a first half-wave plate and a second half-wave plate located on the light-in side of the liquid crystal cell, wherein the order of the liquid crystal grating units on the light-in side is 1, the order of the liquid crystal grating units on the light-out side is n, and n is an integer greater than or equal to 2; The first half-wave plate and the corresponding second half-wave plate are laminated to form n functional film layers; The i-th functional film layer is laminated to the light-in side surface of the i-th liquid crystal cell, the i-th adhesive layer is laminated to the light-out side surface of the i-th liquid crystal cell, and the n-th functional film layer is laminated to the light-in side surface of the n-th liquid crystal cell to form n liquid crystal grating units; The n liquid crystal grating units are laminated to form the liquid crystal grating; Wherein, i < n, and i is a positive integer.

17. A lamination method of a liquid crystal grating, comprising: providing at least two functional sub-layers and at least one liquid crystal cell; stacking the at least two functional sub-layers to form a functional film layer; laminating the functional film layer to one side of the liquid crystal cell to form a liquid crystal grating unit of the liquid crystal grating.

18. The liquid crystal grating bonding method according to claim 17, wherein, The liquid crystal grating comprises at least two liquid crystal grating units, and after the functional film layer is laminated to one side of the liquid crystal cell to form the liquid crystal grating unit, the lamination method further comprises: stacking the at least two liquid crystal grating units in turn to form the liquid crystal grating.

19. The method of claim 17, wherein the liquid crystal grating is formed by applying a voltage to the liquid crystal grating. The at least two functional sub-layers comprise a first half-wave plate and a second half-wave plate, the first half-wave plate and the second half-wave plate are laminated by using a roll-to-roll process, and the optical axis direction of the first half-wave plate and the optical axis direction of the second half-wave plate are different.

20. The method of claim 17, wherein the liquid crystal grating is formed by applying a liquid crystal material to the substrate and applying a voltage to the liquid crystal material. The liquid crystal grating comprises n liquid crystal grating units laminated by n-1 adhesive layers, each of the liquid crystal grating units comprises a liquid crystal cell and a first half-wave plate and a second half-wave plate located on the light-in side of the liquid crystal cell, wherein the order of the liquid crystal grating units on the light-in side is 1, the order of the liquid crystal grating units on the light-out side is n, and n is an integer greater than or equal to 2; the lamination method of the liquid crystal grating comprises: providing n first half-wave plates, n second half-wave plates, n liquid crystal cells, and n-1 adhesive layers; laminating the first half-wave plate and the corresponding second half-wave plate to form n functional film layers; laminating the i-th functional film layer to the light-in side surface of the i-th liquid crystal cell, laminating the i-th adhesive layer to the light-out side surface of the i-th liquid crystal cell, and laminating the n-th functional film layer to the light-in side surface of the n-th liquid crystal cell to form n liquid crystal grating units; laminating the n liquid crystal grating units to form the liquid crystal grating; Wherein, i < n, and i is a positive integer.

21. The method of claim 17, wherein the liquid crystal grating is formed by applying a liquid crystal material to the substrate and applying a voltage to the liquid crystal material. The liquid crystal grating comprises n liquid crystal grating units adhered by n-1 adhesive layers, each of the liquid crystal grating units comprises a liquid crystal cell and a first half-wave plate and a second half-wave plate located at the light-in side of the liquid crystal cell, wherein the order of the liquid crystal grating units at the light-in side is 1, the order of the liquid crystal grating units at the light-out side is n, and n is an integer greater than or equal to 2; and the adhering method of the liquid crystal grating comprises: providing n first half-wave plates, n second half-wave plates, n liquid crystal cells and n-1 adhesive layers; adhering the first half-wave plate and the corresponding second half-wave plate, adhering the jth adhesive layer, the j+1th first half-wave plate and the corresponding second half-wave plate, to form n functional film layers; adhering the first functional film layer to the light-in side surface of the first liquid crystal cell, adhering the kth functional film layer to the light-in side surface of the kth liquid crystal cell, to form n liquid crystal grating units; adhering the n liquid crystal grating units to form the liquid crystal grating; wherein j < n, 1 < k ≤ n, and j and k are positive integers.

22. The liquid crystal grating bonding method according to claim 20 or 21, wherein, n = 2 or n = 3.

23. A three-dimensional display device comprising a backlight module, a spatial light modulator, a converging field lens and the liquid crystal grating according to any one of claims 1-16, which are sequentially stacked; the backlight module is configured to provide a field sequential collimating coherent backlight required for display; the spatial light modulator is configured to modulate the phase and amplitude of the field sequential collimating coherent backlight; the converging field lens is configured to converge the modulated field sequential collimating coherent backlight to the liquid crystal grating; the liquid crystal grating is configured to transmit left-eye pictures and right-eye pictures in a three-dimensional optical image to human eyes.

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