Polarization grating device and liquid crystal display

Abstract

A polarization grating device and a liquid crystal display are provided. The polarization grating device includes a lens assembly (31), a polarization grating assembly (32), and a phase control assembly (33), which are stacked in sequence. The lens assembly (31) includes a first substrate (311) and a plurality of lenses (312) fixed on the same surface of the first substrate (311). The lens assembly (312) is configured to receive a backlight (L1), and each lens (312) is configured to guide a portion of the backlight (L1) to the polarization grating assembly (32); the polarization grating assembly (32) is configured to convert the backlight (L1) into left-handed circularly polarized light (L11) and right-handed circularly polarized light (L12) and output the converted light; the phase control assembly (33) is configured to receive the left-handed circularly polarized light (L11) and right-handed circularly polarized light (L12), and is configured to convert the left-handed circularly polarized light (L11) and right-handed circularly polarized light (L12) into a light source light (L2) and output the converted light.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Chinese Patent Application No. 202210062307.9, entitled "Polarizing Diffraction Grating Device and Liquid Crystal Display," filed on January 19, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present invention relates to the field of display technology, and in particular to a polarization grating device and a liquid crystal display in which the polarization grating device is used. Conventional Technology [Background technology]

[0003] A conventional liquid crystal display includes a backlight module and a display module, and the display module is configured to display an image based on the backlight emitted by the backlight module. Only a portion of the backlight with a target polarization direction can be used to display an image. Therefore, the liquid crystal display typically further includes a polarizing film located between the backlight module and the display module. The polarizing film is configured to transmit the backlight with a target polarization direction and absorb the backlight with a non-target polarization direction. As a result, a partial loss of the backlight occurs, resulting in a low utilization rate of the backlight.

[0004] In the prior art, a polarization grating (PG) film is used to replace the aforementioned polarizing film in order to improve the utilization rate of the backlight. However, the existing PG film is difficult to apply when the backlight spectrum is wide or the backlight is divergent. Summary of the Invention [Means for solving the problem]

[0005] A first aspect of the present application provides a polarization grating device including a lens assembly, a polarization grating assembly, and a phase control assembly, which are stacked in series; the lens assembly includes a first substrate and a plurality of lenses fixed on a same surface of the first substrate, the lens assembly configured to receive backlight, each lens configured to direct a portion of the backlight to the polarization grating assembly; the polarization grating assembly is configured to convert the backlight into left-handed circularly polarized light and right-handed circularly polarized light for output; The phase control assembly is configured to receive the left-handed circularly polarized light and the right-handed circularly polarized light, and is configured to convert the left-handed circularly polarized light and the right-handed circularly polarized light into a source light and output the source light.

[0006] The polarization grating device may modulate at least a portion of the backlight into a target form of the source light, and when the polarization grating device is used in a corresponding device (e.g., a liquid crystal display or a radar), the light utilization efficiency of the backlight is improved.

[0007] In addition, the polarization grating device in this embodiment further includes a lens assembly. By using the focusing function of the lens assembly on the backlight, even if the divergence angle of the backlight is large (i.e., non-collimation), the backlight can be accurately guided to a specific area on the polarization grating assembly. This helps to reduce the light loss of the backlight and further improves the light utilization rate of the backlight.

[0008] In addition, the polarization grating device in this embodiment further includes a first substrate, which serves to improve the overall mechanical strength of the polarization grating device. The refractive index of each substrate is appropriately set, which can further improve the utilization rate of the backlight.

[0009] In some embodiments, each of the multiple lenses is configured to direct the backlight to a different region on the polarization grating assembly.

[0010] Since not all areas of the polarization grating assembly can convert the backlight, the backlight may be guided separately to each area on the polarization grating assembly that can convert the backlight by using multiple lenses, which helps to improve the light utilization rate of the backlight.

[0011] In some embodiments, each lens is strip-shaped, and the lenses are arranged parallel to one another in the first direction.

[0012] In some embodiments, the multiple lenses are arranged in a lens array comprising multiple rows and multiple columns.

[0013] In some embodiments, the polarization grating assembly includes a polarization grating layer that includes a plurality of liquid crystal molecules, at least some of the plurality of liquid crystal molecules having different polarization angles, such that the polarization grating layer is configured to convert and output the backlight as left-handed and right-handed circularly polarized light.

[0014] Natural light can be considered as a combination of two orthogonal circularly polarized lights. The natural backlight is first converted into left and right circularly polarized lights using the polarization grating layer, which can then be converted into linearly polarized source light through phase retardation.

[0015] In some embodiments, the polarization grating layer includes a plurality of polarization regions, each lens corresponding to one of the polarization regions, each lens configured to direct a portion of the backlight to the corresponding polarization region, and each polarization region configured to convert the received backlight into left-handed and right-handed circularly polarized light for output.

[0016] In some embodiments, the projection of each lens on the polarization grating layer at least partially overlaps a corresponding polarization region.

[0017] That is, a pair of lenses and polarizing regions corresponding to each other are in a spatially opposing relationship, whereby the lenses guide the backlight to the corresponding polarizing regions.

[0018] In some embodiments, the multiple polarizing regions include multiple first polarizing regions and multiple second polarizing regions, and the direction of left-handed circularly polarized light emitted from each first polarizing region is different from the direction of left-handed circularly polarized light emitted from each second polarizing region, and the direction of right-handed circularly polarized light emitted from each first polarizing region is different from the direction of right-handed circularly polarized light emitted from each second polarizing region.

[0019] In this way, the optical paths of left and right circularly polarized light are separated by using a first polarizing region and a second polarizing region, whereby phase retardation is then performed separately for the left and right circularly polarized light.

[0020] In some embodiments, the direction of left-handed circularly polarized light exiting each first polarization region is the same as the direction of right-handed circularly polarized light exiting each second polarization region, and the direction of right-handed circularly polarized light exiting each first polarization region is the same as the direction of left-handed circularly polarized light exiting each second polarization region.

[0021] In this way, the regions on the phase control assembly that are configured to receive left-handed and right-handed circularly polarized light separately are regularly distributed, thereby simplifying the manufacturing process, which also helps to avoid the case where the optical paths of the left-handed and right-handed circularly polarized light cross each other during their propagation.

[0022] In some embodiments, the deflection angle distribution law of the liquid crystal molecules in each of the first polarizing regions is different from the deflection angle distribution law of the liquid crystal molecules in each of the second polarizing regions.

[0023] In this way, left-handed circularly polarized light and right-handed circularly polarized light can be emitted separately from the first polarizing region and the second polarizing region.

[0024] In some embodiments, the polarization grating layer includes a plurality of polarizing sub-layers stacked in sequence, each polarizing sub-layer including a plurality of polarizing regions, each polarizing sub-layer configured to convert the backlight into left-handed circularly polarized light and right-handed circularly polarized light; The polarization angle distribution law of the liquid crystal molecules in each polarizing sub-layer is different.

[0025] The polarization grating layer is arranged in a multi-layer structure (including multiple polarizing sub-layers), which helps to improve the overall polarization state conversion efficiency of the backlight when the wavelength range of the backlight is large.

[0026] In some embodiments, the polarization grating layer includes a first polarizing sublayer, a second polarizing sublayer, and a third polarizing sublayer stacked in sequence; The first polarizing sub-layer is configured to convert the backlight within a red light wavelength range into left-handed and right-handed circularly polarized light for output; the second polarizing sub-layer is configured to convert the backlight within a green light wavelength range into left-handed and right-handed circularly polarized light for output; and the third polarizing sub-layer is configured to convert the backlight within a blue light wavelength range into left-handed and right-handed circularly polarized light for output.

[0027] The light source light is used to display an image. The modulation of the image is mainly performed by using three bands of light, namely red, green and blue. Therefore, when the first polarizing sub-layer, the second polarizing sub-layer and the third polarizing sub-layer act on the three bands of light, namely red, green and blue respectively, the image display is facilitated.

[0028] In some embodiments, the polarization grating layer and the plurality of lenses are located on two opposing surfaces of the first substrate, respectively.

[0029] In this way, the number of substrates is reduced and the overall thickness of the polarization grating device is reduced.

[0030] In some embodiments, the polarization grating assembly includes a second substrate and a third substrate, the polarization grating layer being positioned between the second substrate and the third substrate, and the second substrate being fixed to the first substrate such that the polarization grating layer is fixed and supported.

[0031] In this way, the polarization grating layer and the lens do not need to be separately disposed on different surfaces of the same substrate, which helps to simplify the manufacturing process.

[0032] In some embodiments, the phase control assembly comprises a phase control layer; The phase control layer is configured to perform a phase delay on the left-handed circularly polarized light or the right-handed circularly polarized light, convert the light into the source light, and output the light.

[0033] In some embodiments, the phase control layer is a wave plate.

[0034] The wave plate is a fixed pattern structure and the phase control layer is a wave plate, which helps to simplify the manufacturing process.

[0035] In some embodiments, the phase control layer is a liquid crystal layer comprising a plurality of liquid crystal molecules.

[0036] In some embodiments, the phase control layer includes a plurality of first phase control regions and a plurality of second phase control regions, each first phase control region configured to receive left-handed circularly polarized light and each second phase control region configured to receive right-handed circularly polarized light, and the first phase control regions and the second phase control regions configured to perform different phase delays on the received light.

[0037] In some embodiments, when the phase control layer is a liquid crystal layer, the polarization state of the source light emitted from each of the first phase control regions and each of the second phase control regions is adjustable.

[0038] In some embodiments, the phase control assembly further comprises the fourth substrate and the fifth substrate, the phase control layer being located between the fourth substrate and the fifth substrate; A drive circuit is arranged on a surface of the fourth substrate and / or the fifth substrate close to the phase control layer, and the drive circuit is configured to drive and deflect the multiple liquid crystal molecules in the phase control layer to change the polarization direction of at least a portion of the light source light.

[0039] When the diffraction grating device is used in a liquid crystal display, the image displayed by the liquid crystal display may have "bright areas" and "dark areas". Generally, when the light-dark contrast of the image is obvious, the contrast of the image is improved and the display effect is better. However, the liquid crystal display may have problems such as light leakage, which reduces the contrast of the displayed image. In this embodiment, the amount of source light incident from the phase control assembly to the liquid crystal display may be controlled to cooperate with the "bright areas" and "dark areas" of the image displayed by the liquid crystal display. For example, in the region of the phase control assembly corresponding to the "bright areas" of the image, the polarization direction of the source light is controlled to be parallel to the polarization direction of the lower polarizer in the liquid crystal display, so that more source light is transmitted to the liquid crystal display. In the region of the phase control assembly corresponding to the "dark areas" of the image, the polarization direction of the source light is controlled to be perpendicular to the polarization direction of the lower polarizer to prevent the source light from being transmitted to the liquid crystal display. Thus, the phase control layer is arranged as a liquid crystal layer, and the phase retardation performed by the phase control layer on the light is adjustable through the adjustment of the polarization of the liquid crystal molecules. This helps improve the contrast of images displayed by the LCD.

[0040] In some embodiments, the source light is linearly polarized.

[0041] When the polarization grating device is used in a liquid crystal display, it is conducive to transmitting the lower polarizer of the liquid crystal display, in this way, almost all the light source light (there may be light losses caused by other factors, not caused by different polarization directions) can be transmitted through the lower polarizer, thereby improving the light utilization efficiency of the backlight.

[0042] A second aspect of the present application is a liquid crystal display comprising: a backlight module configured to emit a backlight; a polarization grating device located in an optical path of the backlight, the polarization grating device being according to any one of the previous embodiments, and the source light being linearly polarized; a liquid crystal display panel located on an optical path of the light source light and configured to display an image by modulating the light source light based on an image signal, Provide a liquid crystal display.

[0043] In this liquid crystal display, at least a part of the backlight is modulated to linear polarization. When the polarization grating device is used in the liquid crystal display, it is conducive to transmitting the lower polarizer of the liquid crystal display. In this way, almost all the light source light (there may be light loss caused by other factors, not caused by different polarization directions) can be transmitted through the lower polarizer, thereby improving the light utilization rate of the backlight.

[0044] In addition, the polarization grating device of this embodiment further includes a lens assembly. By using the focusing function of the lens assembly on the backlight, even if the divergence angle of the backlight is large (i.e., non-collimation), the backlight can be accurately guided to a specific area on the polarization grating assembly. This helps to reduce the light loss of the backlight and further improves the light utilization rate of the backlight.

[0045] In addition, the polarization grating device of this embodiment further includes a first substrate. The first substrate serves to improve the overall mechanical strength of the polarization grating device. The refractive index of each substrate is set to be within the above range, which serves to further improve the utilization efficiency of the backlight.

[0046] In some embodiments, the liquid crystal display panel includes a lower polarizer, and a polarization direction of at least a portion of the source light is parallel to a polarization direction of the lower polarizer; The polarization direction of at least a portion of the source light is perpendicular to the polarization direction of the lower polarizer; or The polarization direction of at least a portion of the light source light and the polarization direction of the lower polarizing plate form an acute angle.

[0047] In this way, "dark areas" and "light areas" of the image can be matched, which helps to improve the contrast of the image.

[0048] In some embodiments, the phase control assembly further includes a fourth substrate and a fifth substrate, with a phase control layer located between the fourth substrate and the fifth substrate; A drive circuit is arranged on a surface of the fourth substrate and / or the fifth substrate close to the phase control layer, and the drive circuit is configured to drive the liquid crystal molecules in the phase control layer to deflect based on the image signal, thereby changing the polarization direction of at least a portion of the light source light emitted from the phase control layer.

[0049] In this way, the liquid crystal molecules can be driven to deflect based on the image signal, thereby matching the phase retardation to the "dark" and "light" areas of the image, which helps improve the contrast of the image. [Brief description of the drawings]

[0050] [Figure 1] 1 is a diagram showing the structure of a liquid crystal display according to a first embodiment of the present application.

[0051] [Diagram 2] FIG. 2 is a diagram showing the structure of the polarization grating device of FIG.

[0052] [Diagram 3] A diagram of the three-dimensional structure of the lens assembly in Figure 2.

[0053] [Figure 4A] FIG. 4 is a diagram of the process by which the lens assembly of FIG. 3 acts on the backlight.

[0054] [Figure 4B] This is a diagram of the backlight optical path in an existing case that does not have a lens assembly.

[0055] [Diagram 5] 3 is a diagram showing a planar structure of the polarization grating layer of FIG. 2.

[0056] [Figure 6] 6 is a diagram showing the deflection angle distribution of liquid crystal molecules in the first polarizing region and the second polarizing region of FIG. 5. FIG.

[0057] [Figure 7] 7 is a diagram illustrating a process in which each of the first polarizing regions and each of the second polarizing regions in FIG. 6 acts on a backlight.

[0058] [Figure 8] 3 is a diagram showing a planar structure of the phase control layer in FIG. 2.

[0059] [Figure 9] FIG. 2 is a diagram showing a cross-sectional structure of the liquid crystal display of FIG.

[0060] [Figure 10] FIG. 4 is a diagram showing a planar structure of a polarization grating layer according to a second embodiment of the present application.

[0061] [Figure 11]FIG. 4 is a diagram showing a cross-sectional structure of a liquid crystal display according to a second embodiment of the present application.

[0062] [Figure 12] FIG. 11 is a diagram showing the structure of a polarization grating layer according to a third embodiment of the present application.

[0063] [Figure 13] FIG. 11 is a diagram showing the structure of a phase control assembly according to embodiment 4 of the present application.

[0064] [Figure 14] FIG. 11 is a diagram showing a cross-sectional structure of a liquid crystal display according to a fourth embodiment of the present application.

[0065] Explanation of reference numbers of main components LCD display 1 LCD display panel 10 Lower polarizer 11 Array board 12 Liquid crystal layer 13 Color film substrate 14 Upper polarizer 15 Backlight Module 20 Polarization grating device 30 Lens Assembly 31 First substrate 311 Lens 312 Polarization Grating Assembly 32 Second substrate 321 Third board 322 Polarization grating layer 323, 423, 523 Polarizing Sublayers 5231, 5232 Effective area P0 Polarization area A, B, E, F, G, H liquid crystal molecule M Phase control assembly 33, 63 Fourth board 331, 631 Fifth board 332, 632 Drive circuit 6311, 6321 Phase control layer 333, 633 Phase control regions C, D, I, J, K Sub-control areas I1, I2, J1, J2, K1, K2 Backlight L1 Left circular polarization L11 Right circular polarization L12 Light source light L2 Image light L3 Pixel Areas P1, P2, P3 First Direction X Second Direction Y Third Direction Z DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0066] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings in the embodiments of the present application.

[0067] EMBODIMENT 1 Refer to FIG. 1. The liquid crystal display 1 in this embodiment of the present application is, for example, a television, a computer, a mobile phone, or a wearable product. In this embodiment, the liquid crystal display 1 includes a liquid crystal display panel 10, a backlight module 20, and a polarization grating device 30 located between the liquid crystal display panel 10 and the backlight module 20. The backlight module 20 is configured to emit a backlight L1. The polarization grating device 30 is located on the optical path of the backlight L1 and configured to modulate the polarization state of the backlight L1. The backlight emitted after being modulated by the polarization grating device 30 is defined as a source light L2. The liquid crystal display panel 10 is located on the optical path of the source light L2 and configured to modulate the source light L2 to emit an image light L3 from the side of the liquid crystal display panel 10 far from the polarization grating device 30. The image light L3 is used to display an image.

[0068] 2, in this embodiment, the polarization grating device 30 includes a lens assembly 31, a polarization grating assembly 32, and a phase control assembly 33, which are stacked in sequence. The backlight module 20 is located on the side of the lens assembly that is farther from the phase control assembly 33.

[0069] In this embodiment, only the backlight L1 incident on a specific region on the polarization grating assembly 32 can be effectively utilized, and the backlight L1 incident on a region other than the specific region on the polarization grating assembly 32 is lost. However, when the backlight L1 is emitted from the backlight module 20, the backlight L1 has a specific divergence angle. When the backlight L1 is emitted based on the optical path of the backlight L1, a part of the backlight L1 is lost. In this embodiment, the lens assembly 31 is located on the optical path of the backlight L1 and configured to collect the backlight L1 and guide the backlight L1 to a specific region on the polarization grating assembly 32. Therefore, in this embodiment, the utilization rate of the backlight L1 can be improved by using the lens assembly 31. This helps to avoid the loss of a part of the backlight L1 with a large divergence angle.

[0070] In this embodiment, the lens assembly 31 includes a first substrate 311 and a plurality of lenses 312 located on the same surface of the first substrate 311. In this embodiment, the first substrate 311 is made of glass. In another embodiment, the first substrate 311 may be made of another light-transmitting material. The first substrate 311 is configured to carry and fix a plurality of lenses 312. See FIG. 3. The lenses 312 have the same shape and size, each lens 312 is a generally elongated strip having a convex surface, and the plurality of lenses 312 are arranged parallel and closely spaced in a first direction X. Each lens 312 is configured to receive and focus a portion of the backlight L1 onto the polarization grating assembly 32, and each lens 312 is configured to focus the portion of the backlight L1 onto a different region on the polarization grating assembly 32.

[0071] In this embodiment, the radius of curvature of each lens 312 is 0.05 mm to 2.5 mm (including end values), and the refractive index is 1.4 to 1.7 (including end values). For example, the backlight L1 has a divergence angle of 20 degrees. As shown in FIG. 4A, when the backlight L1 passes through the lens assembly 31, the backlight L1 can be separately focused to an effective area P0 on the polarization grating assembly 32 for effective utilization. As shown in FIG. 4B, when the backlight L1 does not pass through the lens assembly 31, the backlight L1 is propagated in the original direction. A part of the backlight light L1 enters the effective area P0. Another part enters a position outside the effective area P0, causing a loss of the backlight. Therefore, the lens assembly 31 in this embodiment helps to improve the light utilization efficiency of the backlight L1.

[0072] 2. The polarization grating assembly 32 includes a second substrate 321, a third substrate 322, and a polarization grating layer 323 located between the second substrate 321 and the third substrate 322. In this embodiment, the second substrate 321 and the third substrate 322 are made of glass. In another embodiment, the second substrate 321 and the third substrate 322 may be made of another light-transmitting material. In this embodiment, the second substrate 321 and the third substrate 322 are configured to collectively support and fix the polarization grating layer 323.

[0073] In this embodiment, the thickness of the polarization grating layer 323 is 10 μm or less.

[0074] In this embodiment, the first substrate 311 and the second substrate 321 are fixed by an adhesive method. In another embodiment, the first substrate 311 and the second substrate 321 may be the same structure layer. That is, in another embodiment, the multiple lenses 312 and the polarization grating layer 323 are respectively located on two opposite surfaces of the same substrate. In this way, the overall thickness of the polarization grating device is reduced. However, in this embodiment, the first substrate 311 and the second substrate 321 are separated, which helps to simplify the manufacturing process of the polarization grating device.

[0075] Please refer to FIG. 5. The polarization grating layer 323 includes a plurality of first polarization regions A and a plurality of second polarization regions B. In this embodiment, the planar structure of the polarization grating layer 323 is rectangular. Each of the first polarization regions A and each of the second polarization regions B is a rectangular region. Each of the first polarization regions A and each of the second polarization regions B has the same size and shape. The plurality of first polarization regions A and the plurality of second polarization regions B are arranged alternately in parallel in the first direction X. In this embodiment, each lens 312 corresponds to only one first polarization region A or only one second polarization region B. In other words, the projection of each lens 312 on the polarization grating layer 323 at least partially overlaps with only one first polarization region A or only one second polarization region B. In this embodiment, the projection of each lens 312 on the polarization grating layer 323 at least partially overlaps with only one first polarization region A or only one second polarization region B. Each lens 312 is configured to direct a portion of the backlight L1 to a corresponding polarized region A or a corresponding second polarized region B.

[0076] Referring to FIG. 6, a plurality of liquid crystal molecules M are present in each of the first polarizing regions A, and a plurality of liquid crystal molecules M are also present in each of the first polarizing regions B. The main difference between the first polarizing region A and the second polarizing region B is that the deflection angle distribution rules of the liquid crystal molecules M in the regions are different. Due to the different deflection angle distribution rules of the liquid crystal molecules M, when the backlight L1 is incident on the polarization grating layer 323, the form of the light emitted from the first polarizing region A and the second polarizing region B is different.

[0077] For each first polarizing region A, the liquid crystal molecules M are arranged in a first direction X. When the deflection angle of the first liquid crystal molecule M in the first direction X is defined as 0°, the deflection angle of the last liquid crystal molecule M in the first direction X is 360°. There is a specific included angle between any two adjacently arranged first liquid crystal molecules M, and the included angle between any adjacently arranged liquid crystal molecules M is the same. In other words, for each first polarizing region A, the liquid crystal molecules M in the first polarizing region A are deflected separately at a specific angle in the counterclockwise direction in turn in the first direction X, so that there is a 360° included angle between the two liquid crystal molecules M that are furthest from each other in the first direction X.

[0078] For each second polarizing region B, a plurality of liquid crystal molecules M are aligned in a first direction X. The main difference from the first polarizing region A is that the plurality of liquid crystal molecules M are deflected in the first direction X in sequence at a specific angle in a clockwise direction, so that there is an included angle of 360° between the two liquid crystal molecules M that are furthest from each other in the first direction X. That is, the main difference between the first polarizing region A and the second polarizing region B is that the deflection angle distribution rules of the liquid crystal molecules M in these regions are different.

[0079] In this embodiment, the backlight L1 is natural light. Please refer to FIG. 7. When the backlight L1 enters the first polarization region A, the first polarization region A emits left circularly polarized light L11 and right circularly polarized light L12. A straight line l perpendicular to the first polarization region A is defined, and the left circularly polarized light L11 and the right circularly polarized light L12 form an included angle θ with the straight line l, and the left circularly polarized light L11 forms an included angle 2θ with the right circularly polarized light L12. In addition, when the backlight light L1 enters the second polarization region B, the second polarization region B also emits left circularly polarized light L11 and right circularly polarized light L12. The main difference between the function of the first polarization region A and the function of the second polarization region B in the backlight L1 is that the directional distribution of the left circularly polarized light L11 and the right circularly polarized light L12 emitted from the first polarization region A is the opposite to the directional distribution of the left circularly polarized light L11 and the right circularly polarized light L12 emitted from the second polarization region B. In other words, the direction of the left-handed circularly polarized light L11 emitted from the first polarization region A is the same as the direction of the right-handed circularly polarized light L12 emitted from the second polarization region B, and the direction of the right-handed circularly polarized light L12 emitted from the first polarization region A is the same as the direction of the left-handed circularly polarized light L11 emitted from the second polarization region B.

[0080] In this embodiment, the size of each polarizing region (A or B) in the first direction X is in the range of 100 μm to 500 μm (including the end values). One polarizing region includes at least two alignment cycles (the deflection angles of the liquid crystal molecules M from 0° to 360° are defined as one alignment cycle), and the size of each alignment cycle in the first direction X is at least 0.5 μm (including the end values).

[0081] Refer to FIG. 2. The phase control assembly 33 includes a fourth substrate 331, a fifth substrate 332, and a phase control layer 333 positioned between the fourth substrate 331 and the fifth substrate 332. In this embodiment, the fourth substrate 331 and the fifth substrate 332 are made of glass. In another embodiment, the fourth substrate 331 and the fifth substrate 332 may be made of another light-transmissive material. The fourth substrate 331 and the fifth substrate 332 are configured to carry and fix the phase control layer 333. In another embodiment, the fourth substrate 331 and the third substrate 322 may be the same material layer. When the fourth substrate 331 and the third substrate 322 are the same material layer, the thickness of the material layer should satisfy the requirements for the distance between the phase control layer 333 and the polarization diffraction grating layer 323.

[0082] In this embodiment, the thickness of the phase control layer 333 satisfies 0.1 mm < d < 10 mm (including the endpoint values). In this embodiment, when the refractive index of the first substrate is represented as n1, 1.3 ≤ n1 ≤ n2 ± 0.1 ≤ 1.8, 1.3 ≤ n2 ≤ n3 ± 0.1 ≤ 1.8, 1.3 ≤ n3 ≤ n4 ± 0.1 ≤ 1.8, 1.3 ≤ n4 ≤ n5 ± 0.1 ≤ 1.7.

[0083] Refer to FIG. 8. In this embodiment, the phase control layer 333 is a quarter-wave plate. The phase control layer 333 includes a plurality of first phase control regions C and a plurality of second phase control regions D. In this embodiment, the planar structure of the phase control layer 333 is rectangular. Each first phase control region C and each second phase control region D are rectangular regions. The first phase control region C and the second phase control region D have the same size and shape. The plurality of first phase control regions C and the plurality of second phase control regions D are arranged alternately in parallel in the first direction X. Each first phase control region C and each second phase control region D are configured to perform a phase delay on the received light.

[0084] Refer to FIG. 9. In this embodiment, each first phase control region C is configured to receive left circularly polarized light L11 and perform a 3 / 4 phase delay on the left circularly polarized light L11; each second phase control region D is configured to receive right circularly polarized light L12 and perform a 1 / 4 phase delay on the right circularly polarized light L12. After the left circularly polarized light L11 and the right circularly polarized light L12 are phase-modulated by the phase control layer 333, the left circularly polarized light L11 and the right circularly polarized light L12 are converted into linearly polarized light and output. That is, the light source light L2 is linearly polarized light. In this embodiment, the light source light L2 output from each first phase control region C and the light source light L2 output from each second phase control region D have the same polarization direction.

[0085] In this way, after the polarization state of the backlight L1 is adjusted by the polarization grating device 30, the backlight L1 is incident on the liquid crystal display panel 10 as the source light L2, and the polarization direction of the source light L2 meets the requirements of the liquid crystal display panel 10, so that the source light L2 can be entirely used by the liquid crystal display panel 10. This avoids the problem in the prior art that the polarization of the light does not meet the requirements of the liquid crystal display panel 10, so that some light is absorbed or reflected. Therefore, the polarization grating device 30 of the present embodiment helps to improve the utilization rate of the backlight L1.

[0086] The liquid crystal display panel 10 includes a lower polarizing plate 11, an array substrate 12, a liquid crystal layer 13, a color film substrate 14 and an upper polarizing plate 15, which are stacked in this order. The lower polarizing plate 11 is closer to the backlight module 20 than the upper polarizing plate 15. The polarization direction of the light source light L2 is parallel to that of the lower polarizing plate 11, that is, the light source light L2 passes through the lower polarizing plate 11 and is modulated by the liquid crystal display panel 10 into the image light L3.

[0087] The working process of the liquid crystal display 1 will be described below with reference to FIG.

[0088] The backlight module 20 emits backlight L1, which is natural light (unpolarized light). The lens assembly 31 receives the backlight L1, and each lens 312 in the lens assembly 31 is configured to focus and guide a portion of the backlight L1 to a corresponding region (the first polarization region A or the second polarization region B) in the polarization grating layer 323. Each of the first polarization region A and each of the second polarization regions B in the polarization grating layer 323 is configured to convert the received backlight L1 into left circularly polarized light L11 and right circularly polarized light L12 and output the converted light. The left circularly polarized light L11 output from the polarization grating layer 323 enters the first phase control region C in the phase control layer 333, and the right circularly polarized light L12 output from the polarization grating layer 323 enters the second phase control region D in the phase control layer 333. The first phase control region C and the second phase control region D are configured to perform different phase delays on the left circularly polarized light L11 and the right circularly polarized light L12, respectively, so that the light emitted from the phase control regions in the phase control layer 333 is linearly polarized light having the same polarization direction, that is, the light source light L2. In addition, the polarization direction of the light source light L2 is parallel to the polarization direction of the lower polarizer 11 of the liquid crystal display panel 10. Therefore, most of the light source light L2 can be transmitted through the lower polarizer 11. That is, the transmittance of the light source light L2 from the lower polarizer 11 is close to 100%. The light source light L2 transmitted through the liquid crystal display panel 10 enters the liquid crystal layer 13, and the array substrate 12 drives and deflects the liquid crystal of the liquid crystal layer 13 based on the image signal to modulate the light source light L2. The light source light L2 modulated by the liquid crystal layer 13 enters the color film substrate 14 and is filtered by the color film substrate 14. The light emitted from the color film substrate 14 is filtered by the upper polarizer 15 and then becomes image light L3. The image light L3 is emitted from the side of the liquid crystal display panel 10 that is farther from the backlight module 20. When the image light L3 enters a human eye, the user can observe an image from the side of the liquid crystal display panel 10 that is farther from the backlight module 20.

[0089] The liquid crystal display 1 of the present application includes a polarization grating device 30. The polarization grating device 30 modulates at least a part of the backlight L1 into linearly polarized light (i.e., the light source light L2) parallel to the polarization direction of the lower polarizer 11 of the liquid crystal display panel 10, so that almost all of the light source light L2 (there may be light loss caused by other factors, not caused by different polarization directions) can be transmitted through the lower polarizer 11, thereby improving the light utilization efficiency of the backlight L1. In addition, the polarization grating device 30 of this embodiment further includes a lens assembly 31. By using the converging function of the lens assembly 31 on the backlight L1, the backlight L1 can be accurately guided to a specific area on the polarization grating assembly 32 even when the divergence angle of the backlight L1 is large (i.e., non-collimation). This helps to reduce the light loss of the backlight L1 and further improve the light utilization efficiency of the backlight L1.

[0090] In addition, the polarization grating device 30 of this embodiment further includes a first substrate 311, a second substrate 321, a third substrate 322, a fourth substrate 331, and a fifth substrate 332. The above substrates help to improve the overall mechanical strength of the polarization grating device 30. The refractive index of each substrate can be set in the above range, which helps to further improve the light utilization efficiency of the backlight L1.

[0091] In another embodiment, the polarization grating device 30 in the present application may alternatively be used in a radar. When the polarization grating device 30 is used in a radar, the source light L2 is a polarized light, and the source light L2 has a smaller wavelength range, and is used to detect the distance between a target object in the environment and the radar, or to detect the three-dimensional structure of a target object in the environment.

[0092] EMBODIMENT 2 The difference between the liquid crystal display of this embodiment and the liquid crystal display of embodiment 1 is mainly that the polarizing grating layer of the liquid crystal display of this embodiment includes multiple (more than two) polarizing region types. The following mainly describes this difference.

[0093] Refer to FIG. 10. The polarization grating layer 423 in this embodiment includes four polarization region types. That is, the polarization grating layer 423 includes a plurality of first polarization regions E, a plurality of second polarization regions F, a plurality of third polarization regions G, and a plurality of fourth polarization regions H. The number of the first polarization regions E, the number of the second polarization regions F, the number of the third polarization regions G, and the number of the fourth polarization regions H are the same. Each polarization region is configured to receive a portion of the backlight L1, convert a portion of the backlight L1 into left circularly polarized light L11 and right circularly polarized light L12, and output the light.

[0094] In this embodiment, the differences between the first polarizing region E, the second polarizing region F, the third polarizing region G and the fourth polarizing region H are mainly in that the liquid crystal polarization direction distribution rules in the first polarizing region E, the second polarizing region F, the third polarizing region G and the fourth polarizing region H are different, and the directions of the left circularly polarized light L11 and the right circularly polarized light L12 emitted from the first polarizing region E, the second polarizing region F, the third polarizing region G and the fourth polarizing region H are different.

[0095] As shown in FIG. 10, in this embodiment, each of the first polarizing regions E, each of the second polarizing regions F, each of the third polarizing regions G, and each of the fourth polarizing regions H is a square of the same area. In the first direction X, the first polarizing regions E and the second polarizing regions F are alternately arranged, and one side of each of the first polarizing regions E and one side of each of the second polarizing regions F form an angle of 45° with respect to the first direction X. In the second direction Y perpendicular to the first direction X, the third polarizing region G and the fourth polarizing region H are alternately arranged, and one side of each of the third polarizing regions G and one side of each of the fourth polarizing regions H form an angle of 45° with respect to the first direction X. In this embodiment, the first polarizing region E, the second polarizing region F, the third polarizing region G, and the fourth polarizing region H that are adjacently arranged are joined to form a square.

[0096] 10 and 11. In this embodiment, the lenses 312 in the lens assembly 31 are arranged in one-to-one correspondence with the first polarization regions E, the second polarization regions F, the third polarization regions G, and the fourth polarization regions H in accordance with the arrangement of the polarization grating layer 423. In other words, the lenses 312 in the lens assembly 31 are arranged in an array including a plurality of rows and a plurality of columns, and the row direction and the column direction are each at an angle of 45° with the first direction X. The projection of each lens 312 in the lens assembly 31 onto the polarization grating layer 423 at least partially overlaps with only one polarization region.

[0097] In this embodiment, in accordance with the arrangement of the polarization regions in the polarization grating layer 423, the multiple phase control regions in the phase control layer 333 are also arranged in one-to-one correspondence with the multiple first polarization regions E, the multiple second polarization regions F, the multiple third polarization regions G, and the multiple fourth polarization regions H. That is, the left-handed circularly polarized light L11 or the right-handed circularly polarized light L12 emitted from the first polarization region E, the second polarization region F, the third polarization region G, and the fourth polarization region H arranged adjacently are focused on the same phase control region in the phase control layer 333.

[0098] In the first embodiment, since the polarization grating layer includes two types of polarization regions arranged alternately in the first direction X, the source light emitted from the polarization grating layer is mainly symmetric and uniform in the first direction X. However, in the present embodiment, the polarization grating layer 423 includes four types of polarization regions (E, F, G, H), so the source light L2 emitted from the polarization grating layer 423 is symmetric and uniform in both the first direction X and the second direction Y.

[0099] In another embodiment, the polarization grating layer can include another number of polarization region types, for example, can include three types of polarization regions. When the number of polarization region types changes, the number and arrangement method of the lenses and phase control regions change accordingly. The deflection angle distribution laws of the liquid crystal molecules in different types of polarization regions are different. Therefore, the liquid crystal display in this embodiment can realize all the beneficial effects of the liquid crystal display 1 in embodiment 1. On this basis, in the liquid crystal display of this embodiment, the polarization grating layer 423 includes multiple (more than two) polarization region types, which helps to improve the symmetry and uniformity of the light source light, thereby improving the effect of displaying an image by the liquid crystal display.

[0100] EMBODIMENT 3 The liquid crystal display of this embodiment differs from the liquid crystal display 1 of embodiment 1 mainly in that the polarization grating layer of the liquid crystal display of this embodiment has a multi-layer structure. This difference will be mainly described below.

[0101] Refer to FIG. 12. The polarization grating layer 523 in this embodiment includes a first polarization sub-layer 5231 and a second polarization sub-layer 5232 stacked in order. The first polarization sub-layer 5231 and the second polarization sub-layer 5232 can be configured to convert the backlight L1 into left-handed circularly polarized light L11 and right-handed circularly polarized light L12. In this embodiment, the wavelength of the backlight L1 is 380 nm to 780 nm (including end values). The thickness of each polarization sub-layer 5231 and the second polarization sub-layer 5232 is in the range of 1 μm to 5 μm (including end values), for example, the thickness is 1.833 μm. The total thickness of the polarization grating layer 323 is 10 μm or less.

[0102] The first polarizing sublayer 5231 and the second polarizing sublayer 5232 each include a plurality of liquid crystal molecules M. The plurality of liquid crystal molecules M in the first polarizing sublayer 5231 and the plurality of liquid crystal molecules M in the second polarizing sublayer 5232 each have a deflection angle distribution law. In this embodiment, the deflection angle distribution laws of the liquid crystal molecules M in the first polarizing sublayer 5231 and the second polarizing sublayer 5232 are different.

[0103] As shown in FIG. 12, a third direction Z perpendicular to the first direction X and the second direction Y is defined. The liquid crystal molecules M in the first polarizing sublayer 5231 and the second polarizing sublayer 5232 have a rotation tendency in the third direction Z, and the rotation tendencies of the liquid crystal molecules M in the first polarizing sublayer 5231 and the second polarizing sublayer 5232 in the third direction Z are opposite. That is, the liquid crystal molecules M in the first polarizing sublayer 5231 rotate counterclockwise in the third direction Z, and the liquid crystal molecules M in the second polarizing sublayer 5232 rotate clockwise in the third direction Z. In this embodiment, the maximum rotation angle of the liquid crystal molecules M in each of the first polarizing sublayer 5231 and the second polarizing sublayer 5232 in the third direction Z is 70°.

[0104] The thicknesses of the first polarizing sub-layer 5231 and the second polarizing sub-layer 5232, as well as the deflection angle distribution law of the liquid crystal molecules M, are set to make the overall polarization efficiency of the polarization grating layer 523 high for the backlight L1 with a wavelength of 380 nm to 780 nm. For the backlight L1 with a different wavelength range, the number and thickness of the polarizing sub-layers, as well as the deflection angle distribution law of the liquid crystal molecules can be adjusted to improve the polarization efficiency of the backlight L1.

[0105] In a modified embodiment, each polarizing sub-layer (the first polarizing sub-layer 5231 or the second polarizing sub-layer 5232) may include multiple polarizing region types as described in embodiment 2. In this way, the symmetry and uniformity of the light emitted from each polarizing sub-layer is improved, and the effect of displaying an image by the liquid crystal display panel is improved. In another embodiment, the polarizing grating layer 523 may include another number of polarizing sub-layers. Therefore, the liquid crystal display in this embodiment can realize all the beneficial effects of the liquid crystal display 1 in embodiment 1. On this basis, in the liquid crystal display in this embodiment, the polarizing grating layer 523 is arranged to be a multi-layer structure, which is helpful to improve the polarization state conversion efficiency of the backlight L1 when the wavelength range of the backlight L1 is large. Also, as described in embodiment 2, if each polarizing sub-layer includes multiple polarizing region types, the effect of displaying an image by the liquid crystal display panel is further improved.

[0106] EMBODIMENT 4 The difference between the liquid crystal display of this embodiment and the liquid crystal display 1 of embodiment 1 is mainly that the structure and function of the phase control assembly in the liquid crystal display of this embodiment are different from the structure and function of the phase control assembly 33 in embodiment 1. The following mainly describes this difference.

[0107] 13. In this embodiment, the phase control assembly 63 includes a fourth substrate 631, a fifth substrate 632, and a phase control layer 633 located between the fourth substrate 631 and the fifth substrate 632.

[0108] In this embodiment, the phase control layer 633 is a liquid crystal layer and includes a plurality of liquid crystal molecules. In this embodiment, the thickness of the phase control layer 633 is 0.1 mm or less. In this embodiment, the fourth substrate 631 and the fifth substrate 632 are respectively provided with driving circuits 6311 and 6321. The driving circuits 6311 and 6321 are configured to output driving signals to the phase control layer 633 based on an image signal to drive the liquid crystal molecules in the phase control layer 633 to deflect by a certain angle. Different deflection angles of the liquid crystal molecules result in different phase delays being performed on the light received by the phase control layer 633. In another embodiment, the driving circuits 6311 and 6321 may alternatively be located on only one of the fourth substrate 631 and the fifth substrate 632. This is not limited in the present application. That is, the phase control assembly 63 in this embodiment does not have a fixed structure as described in embodiment 1, and the deflection angle of the liquid crystal molecules in this embodiment is variable. Therefore, the phase control assembly 63 controls the light phase in an adjustable manner based on the image signal. The driving signal is a voltage signal. The voltage value of the driving signal can be changed, which changes the deflection angle of the liquid crystal molecules in the phase control layer 633, and changes the phase delay applied to the light by the phase control layer 633.

[0109] In this embodiment, the light source light L2 emitted from the phase control layer 633 is also linearly polarized. However, the driving signal may be changed so that different regions of the phase control layer 633 impart different phase delays to the light. In this way, the polarization directions of the light source light L2 emitted from different regions of the phase control layer 633 are different. When the polarization direction of the light source light L2 is parallel to the polarization direction of the lower polarizer, most of the light source light L2 is transmitted through the lower polarizer. When the polarization direction of the light source light L2 is perpendicular to the polarization direction of the lower polarizer, most of the light source light L2 is blocked by the lower polarizer and cannot enter the liquid crystal display panel. When there is another included angle between the polarization direction of the light source light L2 and the polarization direction of the lower polarizer, part of the light source light L2 may be transmitted from the lower polarizer to the liquid crystal display panel, and the amount of the light source light L2 that can be transmitted varies based on the included angle.

[0110] For a liquid crystal display panel, the image displayed on the liquid crystal display panel may have "bright areas" and "dark areas". Generally, when the light-dark contrast of the image is obvious, the contrast of the image is improved and the display effect is better. However, the liquid crystal display panel may have problems such as light leakage, which reduces the contrast of the displayed image. In this embodiment, the amount of the source light L2 incident on the liquid crystal display panel from the phase control assembly 63 may be controlled to cooperate with the "bright areas" and "dark areas" of the image displayed on the liquid crystal display panel. For example, in the area of ​​the phase control assembly 63 corresponding to the "bright areas" of the image, the polarization direction of the source light L2 is controlled to be parallel to the polarization direction of the lower polarizer, so that more of the source light L2 is transmitted to the liquid crystal display panel. In the area of ​​the phase control assembly 63 corresponding to the "dark areas" of the image, the polarization direction of the source light L2 is controlled to be perpendicular to the polarization direction of the lower polarizer 11, which prevents the source light L2 from being transmitted to the liquid crystal display panel 10.

[0111] The case shown in Fig. 14 is used as an example. The horizontal direction in Fig. 14 is defined as the polarization direction of the lower polarizer 11, and the dashed arrow in Fig. 14 represents the polarization direction of the source light L2 emitted from the phase control assembly 63. The image includes a first pixel region P1, a second pixel region P2, and a third pixel region P3, where the first pixel region P1 has the highest brightness and the third pixel region P3 has the lowest brightness. The phase control layer 633 includes a first phase control region I, a second phase control region J, and a third phase control region K corresponding to the pixel regions (P1, P2, P3).

[0112] The first phase control region I corresponds to the first pixel region P1. The polarization direction of the light source light L2 emitted from the first phase control region I is the same as the polarization direction of the lower polarizer 11, and most of the light source light L2 can pass through the lower polarizer 11 and enter the first pixel region P1. The second phase control region J corresponds to the second pixel region P2. The polarization direction of the light source light L2 emitted from the second phase control region J forms an acute angle with the polarization direction of the lower polarizer 11, and some of the light source light L2 can pass through the lower polarizer 11 and enter the second pixel region P2. The third phase control region K corresponds to the third pixel region P3. The polarization direction of the light source light L2 emitted from the third phase control region K is perpendicular to the polarization direction of the lower polarizer 11, and most of the light source light L2 is blocked by the lower polarizer 11 and cannot enter the third pixel region P3.

[0113] Specifically, in this embodiment, the first phase control region I includes a plurality of first sub-control regions I1 (only two are shown in FIG. 14) and a plurality of second sub-control regions I2 (only two are shown in FIG. 14). For the arrangement of the plurality of first sub-control regions I1 and the plurality of second sub-control regions I2, please refer to FIG. 7. Each first sub-control region I1 in the first phase control region I is configured to receive right-handed circularly polarized light L12 output from the polarization grating assembly 32 and perform 3 / 4 phase delay. Each second sub-control region I2 in the first phase control region I is configured to receive left-handed circularly polarized light L11 output from the polarization grating assembly 32 and perform 1 / 4 phase delay. In this way, the light source light L2 output from the first phase control region I is linearly polarized light having the same polarization direction as the lower polarizer 11.

[0114] The second phase control region J includes a plurality of first sub-control regions J1 (only two are shown in FIG. 14) and a plurality of second sub-control regions J2 (only two are shown in FIG. 14). For the arrangement of the plurality of first sub-control regions J1 and the plurality of second sub-control regions J2, please refer to FIG. 7. Each first sub-control region J1 in the second phase control region J is configured to receive the right circularly polarized light L12 outputted from the polarization grating assembly 32 and perform a 3 / 8 phase delay. Each second sub-control region J2 in the second phase control region J is configured to receive the left circularly polarized light L11 outputted from the polarization grating assembly 32 and perform a 5 / 8 phase delay. In this way, the light source light L2 outputted from the second phase control region J becomes linearly polarized light that forms an acute angle with the polarization direction of the lower polarizer 11.

[0115] The third phase control region K includes a plurality of first sub-control regions K1 (only two are shown in FIG. 14) and a plurality of second sub-control regions K2 (only two are shown in FIG. 14). For the arrangement of the plurality of first sub-control regions K1 and the plurality of second sub-control regions K2, please refer to FIG. 7. Each first sub-control region K1 in the third phase control region K is configured to receive left-handed circularly polarized light L11 output from the polarization grating assembly 32 and perform 3 / 4 phase delay. Each second sub-control region K2 in the third phase control region K is configured to receive right-handed circularly polarized light L12 output from the polarization grating 32 and perform 1 / 4 phase delay. In this way, the light source light L2 output from the third phase control region K becomes linearly polarized light perpendicular to the polarization direction of the lower polarizer 11.

[0116] The liquid crystal display in this embodiment can achieve all the beneficial effects described in embodiment 1. On this basis, in this embodiment, the phase retardation performed by the phase control layer 633 on the light is adjustable, which helps to improve the contrast of the image displayed by the liquid crystal display.

[0117] In addition, in the liquid crystal display of this embodiment, the polarization grating layer may be the one described in embodiment 2 or embodiment 3. This makes it possible to realize all of the beneficial effects described in embodiment 2 or embodiment 3.

[0118] Those skilled in the art should realize that the above implementations are merely used to illustrate the present invention, and are not intended to limit the present invention. Appropriate modifications and variations made to the above embodiments will fall within the scope of protection of the present invention as long as the modifications and variations fall within the essence and spirit of the present invention.

Claims

1. A polarization grating device having a lens assembly, a polarization grating assembly, and a phase control assembly, which are stacked in sequence, comprising: the lens assembly includes a first substrate and a plurality of lenses fixed on a same surface of the first substrate, the lens assembly configured to receive backlight, each lens configured to direct a portion of the backlight to the polarization grating assembly; the polarization grating assembly is configured to convert the backlight into left-handed and right-handed circularly polarized light and emit the light; the phase control assembly is configured to receive the left circularly polarized light and the right circularly polarized light, and to convert the left circularly polarized light and the right circularly polarized light into a source light and output the source light. Polarization grating device.

2. The polarization grating device of claim 1 , wherein each of the lenses is configured to direct the backlight to a different region of the polarization grating assembly.

3. 3. The polarization grating device of claim 1, wherein each lens is strip-shaped, and the lenses are arranged parallel to each other in a first direction.

4. The polarization grating device of claim 1 or 2, wherein the plurality of lenses are arranged in a lens array comprising a plurality of rows and a plurality of columns.

5. 5. The polarization grating device of claim 3, wherein the polarization grating assembly includes a polarization grating layer including a plurality of liquid crystal molecules, at least some of the liquid crystal molecules having different polarization angles, such that the polarization grating layer is configured to convert the backlight into the left-handed circularly polarized light and the right-handed circularly polarized light for output.

6. 6. The polarization grating device of claim 5, wherein the polarization grating layer includes a plurality of polarization regions, each lens corresponding to one of the polarization regions, each lens configured to direct a portion of the backlight to a corresponding polarization region, and each polarization region configured to convert the received backlight into the left-handed circularly polarized light and the right-handed circularly polarized light for output.

7. The polarization grating device of claim 6 , wherein the projection of each lens on the polarization grating layer at least partially overlaps the corresponding polarizing region.

8. 8. The polarization diffraction grating device of claim 6, wherein the plurality of polarization regions include a plurality of first polarization regions and a plurality of second polarization regions, the direction of left-handed circularly polarized light emitted from the plurality of first polarization regions is different from the direction of left-handed circularly polarized light emitted from the plurality of second polarization regions, and the direction of right-handed circularly polarized light emitted from the plurality of first polarization regions is different from the direction of right-handed circularly polarized light emitted from the plurality of second polarization regions.

9. 9. The polarization diffraction grating device according to claim 6, wherein the direction of the left circularly polarized light emitted from each first polarization region is the same as the direction of the right circularly polarized light emitted from each second polarization region, and the direction of the right circularly polarized light emitted from each first polarization region is the same as the direction of the left circularly polarized light emitted from each second polarization region.

10. 10. The polarization grating device according to claim 8, wherein a polarization angle distribution law of the liquid crystal molecules in each of the first polarization regions is different from a polarization angle distribution law of the liquid crystal molecules in each of the second polarization regions.

11. the polarization grating layer includes a plurality of polarizing sub-layers stacked in sequence, each polarizing sub-layer including a plurality of polarizing regions, each polarizing sub-layer configured to convert the backlight into the left-handed circularly polarized light and the right-handed circularly polarized light; The polarization angle distribution rules of the liquid crystal molecules in each polarizing sub-layer are different. A polarization grating device according to any one of claims 6 to 10.

12. 12. The polarization grating device of claim 5, wherein the polarization grating layer and the plurality of lenses are located on two opposing surfaces of the first substrate, respectively.

13. 12. The polarization grating device of claim 5, wherein the polarization grating assembly includes a second substrate and a third substrate, the polarization grating layer being located between the second substrate and the third substrate such that the polarization grating layer is fixed and supported, and the second substrate is fixed to the first substrate.

14. the phase control assembly includes a phase control layer; The polarization grating device according to claim 1 , wherein the phase control layer is configured to perform a phase delay on the left-handed circularly polarized light or the right-handed circularly polarized light, convert the light into the light source light, and output the light.

15. The polarization grating device of claim 14 , wherein the phase control layer is a wave plate.

16. The polarization grating device of claim 14 , wherein the phase control layer is a liquid crystal layer comprising a plurality of liquid crystal molecules.

17. 17. The polarization grating device of claim 14, wherein the phase control layer includes a plurality of first phase control regions and a plurality of second phase control regions, each of the first phase control regions being configured to receive the left circularly polarized light and each of the second phase control regions being configured to receive the right circularly polarized light, and the first phase control regions and the second phase control regions being configured to perform different phase delays on the received light.

18. 18. The polarization grating device according to claim 17, wherein when the phase control layer is the liquid crystal layer, the polarization state of the light source light emitted from each of the first phase control regions and each of the second phase control regions is adjustable.

19. the phase control assembly further includes a fourth substrate and a fifth substrate, the phase control layer being located between the fourth substrate and the fifth substrate; 20. The polarization grating device of claim 18, wherein a driving circuit is arranged on a surface of the fourth substrate and / or the fifth substrate close to the phase control layer, and the driving circuit is configured to drive and deflect the multiple liquid crystal molecules in the phase control layer to change the polarization direction of at least a portion of the light source light.

20. 20. The polarization grating device of claim 1, wherein the source light is linearly polarized and is used to display an image.

21. a backlight module configured to emit backlight; a polarization grating device located in an optical path of the backlight, the polarization grating device being the polarization grating device according to any one of claims 1 to 18, and the light source light being linearly polarized; a liquid crystal display panel located on an optical path of the light source light and configured to display an image by modulating the light source light based on an image signal. LCD display.

22. The liquid crystal display panel includes a lower polarizing plate, and the polarization direction of at least a part of the light from the light source is parallel to the polarization direction of the lower polarizing plate; The polarization direction of at least a portion of the light source light is perpendicular to the polarization direction of the lower polarizer; or The polarization direction of at least a part of the light from the light source and the polarization direction of the lower polarizing plate form an acute angle.

22. The liquid crystal display of claim 21.

23. the phase control assembly further includes a fourth substrate and a fifth substrate, with a phase control layer located between the fourth substrate and the fifth substrate; A driving circuit is disposed on a surface of the fourth substrate and / or the fifth substrate close to the phase control layer, and the driving circuit is configured to drive the liquid crystal molecules in the phase control layer to deflect the liquid crystal molecules based on the image signal, thereby changing the polarization direction of at least a portion of the light source light emitted from the phase control layer.

23. A liquid crystal display according to claim 21 or 22.

Images