Liquid crystal plane photonic device, preparation method thereof and display device

Abstract

The invention provides a liquid crystal plane photonic device, a preparation method thereof and a display device. The liquid crystal planar photonic device is configured to form diffraction light rays under the irradiation of incident light rays, the diffraction light rays converge to form at least one observation area, and all the observation areas jointly form an observation window of the liquid crystal planar photonic device; the liquid crystal planar photonic device is provided with a flat pixelated polarization grating array; the preparation method comprises the following steps: acquiring first position distribution of each observation area; acquiring second position distribution of each pixelated polarization grating in the pixelated polarization grating array; coding each pixelated polarization grating according to the first position distribution and the second position distribution to obtain a corresponding target grating pattern; and forming a pixelated polarization grating array on the substrate according to the second position distribution and each target grating pattern. According to the preparation method, multi-view image hybrid coding display with higher precision can be realized, and the diffraction efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a liquid crystal planar photonic device, its fabrication method, and a display apparatus. Background Technology

[0002] Vision is a crucial source of information for humans to understand and change the world; over 80% of the information humans acquire is through their eyes. Traditional screen display technology can only record the amplitude information of an image, while light, in addition to amplitude information, also has phase information. 3D displays can provide observers with depth information of images, allowing them to see the occlusion relationships of objects within the image. Furthermore, glasses-free 3D displays enable observers to view 3D images and videos without any auxiliary equipment, offering immense application value in fields such as medicine, education, gaming, military, and aviation.

[0003] Free-form stereoscopic 3D display technology is one of the fastest-growing technologies in glasses-free 3D display. It represents the 3D light field information of an object by projecting multiple two-dimensional parallax images onto a narrow viewing area, forming approximately continuous parallax changes. It features dynamic, color, and large-format characteristics. In free-form stereoscopic display technology, the field-of-view modulation plate plays a crucial role. One type of technology uses a periodically structured field-of-view modulation plate, creating a periodic arrangement of viewing areas within the observation region. However, this geometric optical field-of-view modulation method has limited beam modulation capability, making it difficult to achieve a large viewing angle and prone to crosstalk, ghosting, and eye strain. A second type is based on diffraction optics, adjusting the light emission direction pixel-by-pixel to achieve a vector light field display with a converging viewing angle. This method uses diffraction elements such as gratings to modulate the field of view. While diffraction elements have strong beam control capabilities, due to their inherent characteristics, their diffraction efficiency is generally low, resulting in severe dispersion. Summary of the Invention

[0004] Based on this, the present invention aims to provide an improved planar liquid crystal photonic device and its fabrication method, as well as a display device, to solve at least one of the above-mentioned problems.

[0005] In a first aspect, this application provides a method for fabricating a planar liquid crystal photonic device, wherein the planar liquid crystal photonic device is configured to form diffracted light under the illumination of incident light, the diffracted light converges to form at least one observation area, and each of the observation areas together forms an observation window of the planar liquid crystal photonic device; and the planar liquid crystal photonic device has a flat pixelated polarization grating array.

[0006] The method includes:

[0007] Obtain the first location distribution of each of the observation areas;

[0008] Obtain the second position distribution of each pixelated polarization grating in the pixelated polarization grating array;

[0009] Each pixelated polarization grating is encoded according to the first position distribution and the second position distribution to obtain the corresponding target grating pattern;

[0010] The pixelated polarization grating array is formed on the substrate according to the second position distribution and each of the target grating patterns.

[0011] The above-mentioned method for fabricating planar photonic devices of liquid crystal is based on dual-beam polarization interference exposure. By determining the second position distribution of each pixelated polarization grating and the target grating pattern, the coordinates (x, y), period Λ, and orientation of the pixelated polarization grating are realized. The continuous modulation of four parameters enables higher precision multi-view image hybrid encoding display. At the same time, the above method is beneficial to improve the diffraction efficiency of the liquid crystal planar photonic device, avoid light energy loss, and solve the problem of backlight heat dissipation. In addition, the device obtained according to this preparation method has a flattened pixelated polarization grating array, which is easier to store and transport than relief grating, and easier to fit with the display screen.

[0012] In one embodiment, encoding each pixelated polarization grating according to the first position distribution and the second position distribution to obtain a corresponding target grating pattern includes: obtaining the refractive index of the fabrication material of the pixelated polarization grating; obtaining the incident angle of the incident light on each pixelated polarization grating and the wavelength of the corresponding diffracted light; and determining the period and orientation of the nanograting in each pixelated polarization grating according to the first position distribution, the second position distribution, the incident angle, the wavelength, and the refractive index.

[0013] In one embodiment, at least one pixelated polarization grating has a red sub-pixel polarization grating, a green sub-pixel polarization grating, and a blue sub-pixel polarization grating. After the incident light is incident on the pixelated polarization grating, it forms red polarized diffracted light, green polarized diffracted light, and blue polarized diffracted light, which converge to the same observation area.

[0014] In one embodiment, the observation window has one or more of a point-like observation area, a line-like observation area, and a surface-like observation area.

[0015] In one embodiment, at least two pixelated polarization gratings have a red sub-pixel polarization grating, a green sub-pixel polarization grating, and a blue sub-pixel polarization grating. After the incident light is incident on the at least two pixelated polarization gratings, it forms red polarized diffracted light, green polarized diffracted light, and blue polarized diffracted light, respectively, and converges to at least two observation areas of different shapes.

[0016] In one embodiment, the images in at least two observation areas are displayed at different resolutions.

[0017] In one embodiment, the image display resolution in the central observation area is greater than the image display resolution in the edge observation area.

[0018] In one embodiment, at least one pixelated polarization grating has a red sub-pixel polarization grating, a green sub-pixel polarization grating, and a blue sub-pixel polarization grating. After the incident light is incident on the pixelated polarization grating, it forms red polarized diffracted light, green polarized diffracted light, and blue polarized diffracted light, which converge to one of the at least two observation regions.

[0019] In one embodiment, forming the pixelated polarization grating array on the substrate according to the second position distribution and each of the target grating patterns includes: coating a photo-alignment material on the target surface of the substrate; performing dual-beam polarization interference exposure on the photo-alignment material according to the second position distribution and each of the target grating patterns to form a patterned photo-alignment material; and forming the pixelated polarization grating array on the target surface using the patterned photo-alignment material and a liquid crystal polymer.

[0020] In one embodiment, forming the pixelated polarization grating array on the target surface using the patterned light alignment material and the liquid crystal polymer includes: coating the patterned light alignment material and the target surface with the liquid crystal polymer and curing it to form an initial pixelated polarization grating array; if the thickness of the initial pixelated polarization grating array does not meet the half-wave condition, then continuing to coat the liquid crystal polymer and cure it to form an optimized pixelated polarization grating array, until the thickness of the optimized pixelated polarization grating array meets the half-wave condition, thus obtaining the pixelated polarization grating array.

[0021] In one embodiment, after forming the pixelated polarization grating array on the target surface, the method further includes: disposing a cover plate on the side of the pixelated polarization grating array away from the substrate; wherein the cover plate is configured to cooperate with the substrate to modulate the birefringence of the liquid crystal polymer by applying a voltage, so that the pixelated polarization grating array satisfies the half-wave condition.

[0022] Secondly, this application provides a liquid crystal planar photonic device, which is fabricated based on the method described above.

[0023] The aforementioned planar liquid crystal photonic device can achieve higher precision multi-view image mixing and encoding display, while also having higher diffraction efficiency, which helps to avoid light energy loss and solve the problem of backlight heat dissipation. In addition, the aforementioned planar liquid crystal photonic device has a flattened pixelated polarization grating array, which is easier to store and transport than embossed gratings, and also easier to fit with the display screen.

[0024] Thirdly, this application provides a display device including a liquid crystal planar photonic device as described above.

[0025] The aforementioned display device facilitates a wide viewing area, reduces crosstalk and ghosting, improves chromatic aberration, and thus enhances the user's visual experience. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of a liquid crystal planar photonic device according to an embodiment of this application;

[0028] Figure 2 This is a schematic diagram of the observation area of ​​a liquid crystal planar photonic device according to an embodiment of this application;

[0029] Figure 3 This is a flowchart illustrating the steps of a method for fabricating a liquid crystal planar photonic device according to an embodiment of this application;

[0030] Figure 4 This is a diffraction diagram of a liquid crystal planar photonic device according to an embodiment of this application;

[0031] Figure 5 This is a schematic diagram of the composition of a three-dimensional laser printing system according to an embodiment of this application;

[0032] Figure 6 This is a schematic diagram illustrating the display effect of a liquid crystal planar photonic device according to an embodiment of this application;

[0033] Figure 7 This is a schematic diagram illustrating the display effect of a liquid crystal planar photonic device according to another embodiment of this application;

[0034] Figure 8 This is a schematic diagram illustrating the display effect of a liquid crystal planar photonic device according to another embodiment of this application;

[0035] Figure 9This is a schematic diagram illustrating the display effect of a liquid crystal planar photonic device according to another embodiment of this application;

[0036] Figure 10 This is a schematic diagram illustrating the display effect of a liquid crystal planar photonic device according to another embodiment of this application;

[0037] Figure 11 This is a schematic diagram of the fabrication process of a liquid crystal planar photonic device according to an embodiment of this application;

[0038] Figure 12 This is an exemplary schematic diagram of two-beam polarization interference. Detailed Implementation

[0039] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0040] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0043] The technical solution disclosed in this application is based on two-beam polarization interference.

[0044] In two-beam polarization interference, the reference and object beams have the same amplitude but orthogonal polarization states (vertical and horizontal polarization, left-handed and right-handed polarization). The phase difference between the two beams causes different polarization states at different positions in the interference field, thus converting the phase information of the object beam into polarization information. This phase information can be recorded by a recording medium, such as a photoaligning agent coated on a substrate. Figure 12 , Figure 12 This is an exemplary schematic diagram of two-beam polarization interference. The following is a brief explanation of two-beam polarization interference.

[0045] like Figure 12 As shown, E1 and E2 are right-handed and left-handed circularly polarized lights, respectively, with wavelength λ0. The wave vector of E1 lies in the plane, making an angle θ with the z-axis, while the wave vector of E2 is parallel to the z-axis. The two beams intersect at point O. E1 and E2 have equal amplitudes. If only the complex amplitude is considered, the expressions for E1 and E2 can be given as follows:

[0046]

[0047] Where k1 and k2 are the wave vectors of light waves E1 and E2, The polarized light field formed by polarization interference at point O is: E1 + E2 = x(icosθe) iδ -i)+y(e iδ +1), where, The phase difference between E1 and E2 is θ. When θ is small, cosθ≈1, so the polarized light field can be rewritten as: It can be seen that at point O, a linearly polarized light field is formed, and the direction of linear polarization is related to δ.

[0048] Based on this, a four-parameter three-dimensional color polarization pattern (i.e., a liquid crystal planar photonic device) with continuously variable spatial frequency and orientation of a polarization grating can be obtained. All image information is recorded in the (x,y) plane, consisting of a series of polarization diffraction pixels corresponding to the coordinate positions. Each polarization diffraction pixel is filled by a set of pixelated polarization gratings with a specific period Λ (or spatial frequency) and orientation α. ​​Therefore, this series of polarization diffraction pixels can also be called a pixelated polarization grating array. The diffracted light emitted from the polarization diffraction pixels enters the designated coordinate position on the plane of the observation window, which is located at a certain distance from the plane where the polarization diffraction pixels are located. The spatial frequency and orientation of the pixelated polarization grating can be determined by the incident direction of the illumination light, the direction of the diffracted light, and the wavelength of the diffracted light, combined with the grating equation. The incident direction of the illumination light can be set according to the usage conditions. The direction of the diffracted light is determined by the plane coordinates of the pixelated polarization grating and the light incident position coordinates in the observation window. The wavelength of the diffracted light is determined by the color of the image information corresponding to the polarization diffraction pixel. The observation window is a slit-shaped window parallel to the direction of the line connecting the observer's eyes. This slit-shaped window contains several observation areas, and each observation area corresponds to an observation angle of the three-dimensional image.

[0049] This application provides a method for fabricating a planar photonic device based on a liquid crystal. This method is based on dual-beam polarization interference exposure. By determining the second position distribution of each pixelated polarization grating and the target grating pattern, the coordinates (x, y), period Λ, and orientation of the pixelated polarization grating are determined. The continuous modulation of four parameters enables higher precision multi-view image hybrid encoding display. At the same time, the above method is beneficial to improve the diffraction efficiency of the liquid crystal planar photonic device, avoid light energy loss, and solve the problem of backlight heat dissipation. In addition, the device obtained according to this preparation method has a flattened pixelated polarization grating array, which is easier to store and transport than relief grating, and easier to fit with the display screen.

[0050] Some embodiments of this application will be described below with reference to the accompanying drawings. It should be noted that the following description is for illustrative purposes only and is not intended to limit the scope of protection of this application.

[0051] like Figure 1 and Figure 2 As shown, this application provides a liquid crystal planar photonic device 100, including a substrate 110 and a pixelated polarization grating array 120 formed on the target surface of the substrate 110. The pixelated polarization grating array 120 can form multiple diffracted rays under the illumination of incident light, and each diffracted ray can converge to form four observation areas P1, P2, P3, and P4. Each observation area together forms the observation window 130 of the liquid crystal planar photonic device.

[0052] For example, such as Figure 3As shown, the liquid crystal planar photonic device 100 can be fabricated by the following method:

[0053] S100, Obtain the first position distribution of each observation area.

[0054] S200: Obtain the second position distribution of each pixelated polarization grating in the pixelated polarization grating array.

[0055] Optionally, taking observation area P1 as an example, converging rays emitted from pixelated polarization gratings p11, p12, p13, and p14 converge to observation area P1. Each observation area P1, P2, P3, and P4 has a preset first position distribution, and each pixelated polarization grating has a preset second position distribution. The position coordinates of each observation area can be determined based on the first position distribution, and the position coordinates of each pixelated polarization grating can be determined based on the second position distribution.

[0056] S300: Encode each pixelated polarization grating according to the first position distribution and the second position distribution to obtain the corresponding target grating pattern.

[0057] Optionally, encoding each pixelated polarization grating mainly involves determining the period and orientation of the nanogratings within each pixelated polarization grating. For example... Figure 4 As shown, the derivation process of the period and orientation of the nanograting is as follows:

[0058] With the center of the phase panel as the origin, assuming that the incident light C is parallel light, it is incident at an angle θ on the pixelated polarization grating A at coordinates (x,y,0). The incident position coordinates of the light source are (0,-z1tanθ,z1). The diffracted light converges to point B (x0,y0,z) in the observation area.

[0059] in, Through a series of derivations, we can obtain:

[0060]

[0061] Therefore, step S300 may include:

[0062] S310. Obtain the refractive index n of the material used to fabricate the pixelated polarization grating;

[0063] S320. Obtain the incident angle θ of the incident light rays incident on each pixelated polarization grating and the wavelength λ of the corresponding diffracted light rays;

[0064] S330. Determine the period Λ and orientation of the pixelated polarization grating based on the first position distribution, the second position distribution, the incident angle θ of the incident light, the wavelength λ of the diffracted light, and the refractive index n.

[0065] S400: Based on the second position distribution and each target grating pattern, a pixelated polarization grating array is formed on the substrate.

[0066] For example, such as Figure 11 As shown, step S400 may include:

[0067] S410, Coating a photo-alignment material onto the target surface of the substrate 110;

[0068] S420. Based on the second position distribution and the target grating pattern, the optical alignment material is subjected to dual-beam polarization interference exposure to form a patterned optical alignment material.

[0069] S430: A pixelated polarization grating array is formed on the target surface using patterned light-aligning materials and liquid crystal polymers.

[0070] For example, substrate 110 can be a basic component used in the field of flat panel displays, such as a glass substrate. The glass substrate has two surfaces arranged opposite each other, and a photo-alignment material can be coated on one of the surfaces (referred to as the target surface in this application). The coating can be achieved by brushing, roller coating, spraying, spin coating, etc. For example, the photo-alignment material can be coated on the target surface by spin coating, and then dried to remove the solvent.

[0071] For example, the molecular structure of photo-aligned materials can undergo chemical reactions (photoisomerization, photodecomposition, photocrosslinking) under linearly polarized light irradiation to achieve directional alignment. Due to intermolecular interactions, this directionally aligned photosensitive material structure can anchor molecules in liquid crystal polymers, thereby achieving the orientation purpose. Therefore, liquid crystal polymers are used as materials for fabricating pixelated polarization gratings, where the refractive index n is the refractive index of the liquid crystal polymer.

[0072] Optionally, the photo-alignment material can include azo compounds, such as the azo dye SD1. For the azo dye SD1, its molecule can be viewed as a cylindrically symmetrical rod-shaped structure, with its absorbing oscillator parallel to the long axis of the molecule. When the polarization direction of the incident ultraviolet light makes an angle >90° with the long axis of the SD1 molecule, SD1 will absorb part of the energy of the polarized ultraviolet light along its long axis and change to a cis configuration. This continues until the angle equals 90°, at which point the molecule no longer absorbs the energy of the polarized light and exists in a stable trans conformation. The long axis orientation of the azo molecule can further anchor the liquid crystal or liquid crystal polymer molecules, causing them to align in an ordered manner along a designed direction.

[0073] For example, exposure can be achieved using a 3D laser printing system or a 3D laser printing method. For instance, a substrate can be placed in a 3D laser printing system, allowing the photo-alignment material to record the resulting polarization information, thus achieving the exposure purpose.

[0074] Optionally, step 400 can be performed as follows: Figure 5 The illustrated 3D laser printing system implementation. (Example) Figure 5 As shown, the three-dimensional laser printing system may include a laser source 8, a quarter-wave plate 9, a spatial filter 10, a reflector 11, a DMD digital micromirror device 12, a first Fourier transform lens 13, a diffraction grating 14, a second Fourier transform lens 15, a field stop 16, a semi-transparent mirror 17, a tube lens 18, a binary split rotationally symmetric waveplate device 19, a miniature objective lens 20, an optical orientation material 21, a two-dimensional precision translation stage 22, an autofocus optical path 23, a motion controller 24, a control computer 25, and a real-time detection optical path 26.

[0075] exist Figure 5 In the process, the linearly polarized laser emitted by the laser source 8 passes through the quarter-wave plate 9, changing its polarization state from linear to circular. After being expanded and collimated by the spatial filter 10, it forms parallel light. After being reflected by the mirror 11, the parallel light is incident on the DMD spatial light modulator 12, which acts as a variable aperture to control the diameter of the parallel beam. The light reflected by the DMD spatial light modulator enters an optical adjustment device that can perform spatial frequency and orientation angle modulation of pixelated polarization gratings, and forms polarization grating fringes with specified spatial frequency and orientation in the region behind the second Fourier transform lens 15. A field stop 16 is provided on the focal plane behind the second Fourier transform lens 15 to limit the imaging area of ​​the interference fringes. The grating fringes passing through the field stop 16 pass through the semi-transparent mirror 17, tube lens 18, binary split rotationally symmetric waveplate device 19, and miniature objective lens 20, forming high-frequency polarization grating fringes on the light orientation material 21 (the aforementioned recording medium). Under the program control set by the control computer 25, the motion controller 24 coordinates the pulse timing of the laser source 8, the movement and rotation of the diffraction grating 14, and the two-dimensional movement of the two-dimensional precision translation stage 22 to record four-parameter modulated three-dimensional image information on the photo-alignment material 21. The real-time detection optical path 26 is used for real-time observation and recording of the imaging process on the surface of the photo-alignment material 21. The autofocus optical path 23 monitors and adjusts the distance between the focusing objective and the surface of the photo-alignment material 21 in real time to ensure accurate imaging of the high-frequency polarization grating fringes on the surface of the photo-alignment material. Optionally, when the diffraction grating 14 is located between the first Fourier transform lens 13 and its rear focal plane, the distance between the diffraction grating 14 and the first Fourier transform lens 13 can be changed by moving the diffraction grating 14, thereby achieving continuous modulation of the spatial frequency parameter Λ of the pixelated polarization grating; or, when the diffraction grating 14 is located between the second Fourier transform lens 15 and its front focal plane, the distance between the diffraction grating 14 and the second Fourier transform lens 15 can be changed by moving the diffraction grating 14, thereby achieving continuous modulation of the spatial frequency parameter Λ of the pixelated polarization grating.

[0076] Figure 5The 3D laser printing system shown can use a semiconductor-pumped solid-state laser source, such as a nanosecond pulse laser source, with an output frequency of over 1000Hz and high pulse energy, which can generate an instantaneous polarized light field for optical orientation of the optically oriented material.

[0077] In some embodiments of this application, at least one pixelated polarization grating has a red sub-pixel polarization grating, a green sub-pixel polarization grating, and a blue sub-pixel polarization grating. Incident light rays, after being incident on the pixelated polarization grating, form red polarized diffracted rays, green polarized diffracted rays, and blue polarized diffracted rays, which converge to the same observation area. Through the red polarized diffracted rays, green polarized diffracted rays, and blue polarized diffracted rays, an observer can observe a color image in this observation area.

[0078] Optional, such as Figure 6 As shown, the liquid crystal planar photonic device 27 is composed of a series of polarization diffraction pixels 28 (i.e., a pixelated polarization grating array), each composed of red sub-pixels 35, green sub-pixels 36, and blue sub-pixels 37. The three color sub-pixels are each filled with a set of pixelated polarization gratings 29 with specific spatial frequencies and orientations. The spatial frequency of the pixelated polarization gratings in each sub-pixel gradually changes from top to bottom, depending on the direction of the illumination light and the position of the observation window. Under illumination, the liquid crystal planar photonic device 27 forms diffracted rays, forming an observation window 31 on a plane at a distance z from the liquid crystal planar photonic device 27. The observation window 31 is composed of multiple point-like observation areas 32, with different observation areas corresponding to images from different viewpoints in a three-dimensional image. The red polarization diffraction rays 38, green polarization diffraction rays 39, and blue polarization diffraction rays 40 representing image information from the same viewpoint in the liquid crystal planar photonic device 27 enter the same point-like observation area, forming a color image.

[0079] In some embodiments of this application, the observation window has one or more of a point-like observation area, a line-like observation area, and a surface-like observation area. A point-like observation area means that the observer can see the image at the coordinates of that point-like observation area; a line-like observation area means that the observer can see the image even if they move up and down within that area; and a surface-like observation area means that the observer can see the image even if they move up, down, left, or right within that area.

[0080] Optional, such as Figure 7As shown, the liquid crystal planar photonic device 27 is composed of a series of polarization diffraction pixels 28 (i.e., a pixelated polarization grating array), each filled with a set of pixelated polarization gratings 29 having a specific spatial frequency and orientation. The spatial frequency of the pixelated polarization gratings in each polarization diffraction pixel 28 gradually changes from top to bottom, depending on the direction of the illumination light and the position of the observation window. Under illumination, the liquid crystal planar photonic device 27 forms diffracted rays, forming an observation window 31 on a plane at a distance z from the liquid crystal planar photonic device 27. The observation window 31 is composed of multiple point-like observation areas 32, line-like observation areas 33, and area-like observation areas 34, with different observation areas corresponding to images from different perspectives in a three-dimensional image. The diffracted rays 30 of the polarization diffraction pixels 28 representing image information from the same perspective in the liquid crystal planar photonic device 27 enter the same point-like observation area / line-like observation area / area-like observation area.

[0081] Furthermore, at least two pixelated polarization gratings have red sub-pixel polarization gratings, green sub-pixel polarization gratings, and blue sub-pixel polarization gratings. When incident light rays are incident on these at least two pixelated polarization gratings, they form red polarized diffracted rays, green polarized diffracted rays, and blue polarized diffracted rays, respectively, which converge to at least two observation regions of different shapes. Thus, color images can be viewed in observation regions of different shapes.

[0082] Optional, such as Figure 8 As shown, the liquid crystal planar photonic device 27 is composed of a series of polarization diffraction pixels 28. Each polarization diffraction pixel 28 consists of red sub-pixels 35, green sub-pixels 36, and blue sub-pixels 37. Each sub-pixel is filled with a set of pixelated polarization gratings 29 with specific spatial frequencies and orientations. The spatial frequency of the pixelated polarization gratings in the liquid crystal planar photonic device 27 gradually changes from top to bottom, depending on the direction of the illumination light and the position of the observation window. Under illumination, the liquid crystal planar photonic device 27 forms diffracted rays, forming an observation window 31 on a plane at a distance z from the liquid crystal planar photonic device 27. The observation window 31 is composed of multiple point-like observation areas 32, line-like observation areas 33, and planar observation areas 34. Different observation areas correspond to images from different perspectives in a three-dimensional diagram. In the liquid crystal planar photonic device 27, the red polarized diffraction ray 38, the green polarized diffraction ray 39, and the blue polarized diffraction ray 40 of the polarized diffraction pixels representing image information from the same viewing angle enter the same point-like observation area 32 / line-like observation area 33 / area-like observation area 34 to form a color image.

[0083] In some embodiments of this application, the image display resolution is different in at least two observation areas. This allows for the implementation of observation windows with gradually varying information density according to the usage scenario. For example, observation windows with normally distributed display resolutions can be implemented, where the image display resolution in the central observation area is greater than that in the edge observation area, thereby achieving effective utilization of polarization diffraction pixels.

[0084] Optional, such as Figure 9 As shown, the liquid crystal planar photonic device 27 is composed of a series of polarization diffraction pixels 28. Each polarization diffraction pixel 28 is filled with a set of pixelated polarization gratings 29 with specific spatial frequencies and orientations. The spatial frequencies of the pixelated polarization gratings 29 in the liquid crystal planar photonic device 27 gradually change from top to bottom, depending on the direction of the illumination light and the position of the observation window. Under illumination, the liquid crystal planar photonic device 27 forms diffracted rays, forming an observation window 31 on a plane at a distance of 27z from the liquid crystal planar photonic device 27. The observation window 31 is composed of multiple point-like observation areas 32, with different observation areas corresponding to images from different perspectives in the three-dimensional image. The polarization diffracted rays 30 of the polarization diffraction pixels 28 representing image information from the same perspective in the liquid crystal planar photonic device 27z converge to the same point-like observation area, resulting in different image display resolutions within different observation areas.

[0085] Furthermore, at least one pixelated polarization grating has a red sub-pixel polarization grating, a green sub-pixel polarization grating, and a blue sub-pixel polarization grating. After incident light is incident on the pixelated polarization grating, it forms red polarized diffracted light, green polarized diffracted light, and blue polarized diffracted light, which converge to one of at least two observation areas. In this way, the polarization diffraction pixels can be effectively utilized while displaying a color image.

[0086] Optional, such as Figure 10 As shown, the liquid crystal planar photonic device 27 is composed of a series of polarization diffraction pixels 28. Each polarization diffraction pixel 28 consists of a red sub-pixel 35, a green sub-pixel 36, and a blue sub-pixel 37. Each sub-pixel is filled with a set of pixelated polarization gratings 29 with specific spatial frequencies and orientations. The spatial frequency of the pixelated polarization gratings 28 in the liquid crystal planar photonic device 27 gradually changes from top to bottom, depending on the direction of the illumination light and the position of the observation window. Under illumination, the liquid crystal planar photonic device 27 forms diffracted rays, forming an observation window 31 on a plane at a distance z from the liquid crystal planar photonic device 27. The observation window 31 is composed of multiple point-like observation areas 32, with different observation areas corresponding to images from different perspectives in the three-dimensional image. The red polarization diffraction rays 38, green polarization diffraction rays 39, and blue polarization diffraction rays 40 of the polarization diffraction pixels 28 representing the same perspective image information in the three-dimensional image 27 enter the same point-like observation area, forming a color image, and the image display resolution differs in different observation areas.

[0087] In some embodiments of this application, the planar liquid crystal photonic device may include a single-layer passive device, such as a liquid crystal display film. In this case, to satisfy the half-wave condition, multiple liquid crystal polymer coating-curing operations can be performed. After multiple liquid crystal polymer coating-curing operations, the film thickness of the liquid crystal material satisfies the half-wave condition, ultimately obtaining the desired planar liquid crystal photonic device. For example, as shown... Figure 11 As shown, step S430 may include:

[0088] S431. A liquid crystal polymer is coated on a patterned light-aligning material and a target surface and then cured to form an initial pixelated polarization grating array.

[0089] S432. If the thickness of the initial pixelated polarization grating array does not meet the half-wave condition, the liquid crystal polymer is coated and cured to form an optimized pixelated polarization grating array until the thickness of the optimized pixelated polarization grating array meets the half-wave condition, thus obtaining the pixelated polarization grating array.

[0090] In some embodiments of this application, the planar photonic device for liquid crystal may include a two-layer active device, such as a liquid crystal cell. In this case, to satisfy the half-wave condition, a cover plate can be disposed on the side of the pixelated polarization grating array away from the substrate. Optionally, the cover plate can be similar to the substrate, such as a transparent glass substrate, or it can be a color filter. The cover plate can cooperate with the substrate to modulate the birefringence of the liquid crystal polymer under the application of voltage, so that the thickness of the liquid crystal layer (pixelated polarization grating array) satisfies the half-wave condition.

[0091] This application also provides a liquid crystal planar photonic device, which is fabricated based on the method described in the foregoing embodiments.

[0092] The aforementioned planar liquid crystal photonic device can achieve higher precision multi-view image mixing and encoding display, while also having higher diffraction efficiency, which helps to avoid light energy loss and solve the problem of backlight heat dissipation. In addition, the aforementioned planar liquid crystal photonic device has a flattened pixelated polarization grating array, which is easier to store and transport than embossed gratings, and also easier to fit with the display screen.

[0093] This application also provides a display device, including a liquid crystal planar photonic device as described in the foregoing embodiments.

[0094] The aforementioned display device facilitates a wide viewing area, reduces crosstalk and ghosting, improves chromatic aberration, and thus enhances the user's visual experience.

[0095] It should be noted that the numbers used to describe and claim certain embodiments of this application, representing quantities or properties, should be understood to be modified in some cases by the terms "approximately," "about," "approximately," or "essentially." For example, unless otherwise stated, "approximately," "about," "approximately," or "essentially" can indicate a variation of ±20% of the value they describe. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed according to the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this application are approximate values, in specific embodiments, such numerical values ​​are set as precisely as feasible.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for fabricating a liquid crystal planar photonic device, characterized in that, The liquid crystal planar photonic device is configured to form diffracted rays under the illumination of incident light, and the diffracted rays converge to form at least one observation area, and each of the observation areas together forms the observation window of the liquid crystal planar photonic device. and, The liquid crystal planar photonic device has a pixelated polarization grating array; The method includes: Obtain the first location distribution of each of the observation areas; Obtain the second position distribution of each pixelated polarization grating in the pixelated polarization grating array; Each pixelated polarization grating is encoded according to the first position distribution and the second position distribution to obtain the corresponding target grating pattern; The pixelated polarization grating array is formed on the substrate according to the second position distribution and each of the target grating patterns.

2. The method according to claim 1, characterized in that, The step of encoding each pixelated polarization grating according to the first position distribution and the second position distribution to obtain the corresponding target grating pattern includes: Obtain the refractive index of the material used to fabricate the pixelated polarization grating; Obtain the incident angle of the incident light rays incident on each of the pixelated polarization gratings and the wavelength of the corresponding diffracted light rays; The period and orientation of the nanogratings in each pixelated polarization grating are determined based on the first position distribution, the second position distribution, the incident angle, the wavelength, and the refractive index.

3. The method according to claim 1 or 2, characterized in that, At least one pixelated polarization grating has a red sub-pixel polarization grating, a green sub-pixel polarization grating, and a blue sub-pixel polarization grating. When the incident light is incident on the pixelated polarization grating, it forms red polarized diffracted light, green polarized diffracted light, and blue polarized diffracted light, which converge to the same observation area.

4. The method according to claim 1 or 2, characterized in that, The observation window has one or more of the following: point-like observation area, line-like observation area, and area-like observation area.

5. The method according to claim 4, characterized in that, At least two pixelated polarization gratings have red sub-pixel polarization gratings, green sub-pixel polarization gratings, and blue sub-pixel polarization gratings. When the incident light is incident on the at least two pixelated polarization gratings, it forms red polarized diffracted light, green polarized diffracted light, and blue polarized diffracted light, respectively, and converges to at least two observation areas of different shapes.

6. The method according to claim 1 or 2, characterized in that, Images in at least two observation areas show different resolutions.

7. The method according to claim 6, characterized in that, The image display resolution in the central observation area is greater than that in the edge observation area.

8. The method according to claim 6, characterized in that, At least one pixelated polarization grating has a red sub-pixel polarization grating, a green sub-pixel polarization grating, and a blue sub-pixel polarization grating. After the incident light is incident on the pixelated polarization grating, it forms red polarized diffracted light, green polarized diffracted light, and blue polarized diffracted light, which converge to one of the at least two observation areas.

9. The method according to claim 1 or 2, characterized in that, The step of forming the pixelated polarization grating array on the substrate according to the second position distribution and each of the target grating patterns includes: A photo-alignment material is coated onto the target surface of the substrate; The optical alignment material is subjected to dual-beam polarization interference exposure according to the second position distribution and each of the target grating patterns to form a patterned optical alignment material; The pixelated polarization grating array is formed on the target surface using the patterned light-aligning material and liquid crystal polymer.

10. The method according to claim 9, characterized in that, The process of forming the pixelated polarization grating array on the target surface using the patterned light-aligning material and liquid crystal polymer includes: The liquid crystal polymer is coated onto the patterned light-aligning material and the target surface and then cured to form an initial pixelated polarization grating array; If the thickness of the initial pixelated polarization grating array does not meet the half-wave condition, the liquid crystal polymer is coated and cured to form an optimized pixelated polarization grating array until the thickness of the optimized pixelated polarization grating array meets the half-wave condition, thus obtaining the pixelated polarization grating array.

11. The method according to claim 9, characterized in that, After forming the pixelated polarization grating array on the target surface, the method further includes: A cover plate is disposed on the side of the pixelated polarization grating array away from the substrate; wherein the cover plate is configured to cooperate with the substrate to modulate the birefringence of the liquid crystal polymer by applying a voltage, so that the pixelated polarization grating array satisfies the half-wave condition.

12. A liquid crystal planar photonic device, characterized in that, The liquid crystal planar photonic device is fabricated based on the method described in any one of claims 1 to 11.

13. A display device, characterized in that, Including the liquid crystal planar photonic device as described in claim 12.

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