Display panel and projection system

Abstract

The utility model provides a display panel and a projection system. The display panel includes: a first substrate; the second substrate is arranged opposite to the first substrate; a liquid crystal layer disposed between the first substrate and the second substrate; the reflecting layer is arranged on one side, facing the second substrate, of the first substrate; the metasurface light splitting structure layer is arranged on the side, away from the first substrate, of the reflecting layer, the metasurface light splitting structure layer comprises a plurality of metasurface light splitting units which are periodically arranged, and at least one metasurface light splitting unit comprises a plurality of metasurface light splitting convergence structures; and the metasurface light splitting unit is used for splitting the white light reflected by the reflecting layer into a plurality of monochromatic lights, and converging the plurality of monochromatic lights to an area where a plurality of sub-pixels of the display panel are located through the metasurface light splitting convergence structure.

Description

Technical Field

[0001] The utility model relates to the technical field of display, in particular to a display panel and a projection system. Background Art

[0002] With the rapid development of display technology, people have higher and higher requirements for display technology. Currently, micro-projection technology has begun to enter the market and is widely used in personal consumption and business occasions, with broad development prospects.

[0003] LCOS (Liquid Crystal On Silicon) projection technology is a new type of reflective liquid crystal projection technology. In order to achieve red, green and blue display, the current LCOS projection solutions mainly include single-chip LCOS projection solutions and three-chip LCOS projection solutions. Among them, the overall volume of the three-chip LCOS projection solution is relatively large, which is not conducive to the miniaturization of the device. The single-chip LCOS projection solution currently mainly includes two methods: color film and color wheel for time domain color separation. However, the conventional color film has a low transmittance and a light efficiency loss of about 60%-70%. The color wheel will cause the display effect to deteriorate due to the influence of frame rate, and will also reduce the light efficiency of the projection system. Therefore, how to improve the optical efficiency of the projection system and reduce the volume of the projection system is one of the important topics studied by researchers in this field.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0005] In one aspect, a display panel is provided, comprising: a first substrate; a second substrate disposed opposite to the first substrate; a liquid crystal layer disposed between the first substrate and the second substrate;

[0006] a reflective layer disposed on a side of the first substrate facing the second substrate; and

[0007] A metasurface light splitting structure layer is arranged on a side of the reflective layer away from the first substrate, wherein the metasurface light splitting structure layer comprises a plurality of metasurface light splitting units arranged periodically, and at least one of the metasurface light splitting units comprises a plurality of metasurface light splitting and converging structures.

[0008] Among them, the super-surface spectroscopic unit is used to: separate the white light reflected by the reflective layer into multiple monochromatic lights, and converge the multiple monochromatic lights to the area where the multiple sub-pixels of the display panel are located through the super-surface spectroscopic convergence structure.

[0009] According to some exemplary embodiments, an orthographic projection of the metasurface light-splitting structure layer on the first substrate falls within an orthographic projection of the reflective layer on the first substrate.

[0010] According to some exemplary embodiments, the metasurface spectroscopic unit includes a plurality of periodically arranged metasurface nanocolumns and a filling layer filled in the gaps between the plurality of metasurface nanocolumns, wherein the metasurface nanocolumns are rotationally symmetric columnar structures.

[0011] According to some exemplary embodiments, the metasurface light splitting structure layer has a lens phase Ψ lens (x, y, f, λ), the lens phase Ψ lens (x, y, f, λ) satisfies equation (1):

[0012]

[0013] Wherein, x, y are the coordinate positions in the two-dimensional coordinate system constructed by the plane where the metasurface light-splitting structure layer is located, λ is the wavelength of light, and f is the focal length of the equivalent lens of the metasurface light-splitting structure layer;

[0014] The display panel further includes a first alignment layer located between the super-surface light-splitting structure layer and the liquid crystal layer, wherein the first alignment layer has a first thickness, wherein:

[0015] The focal length f of the equivalent lens is equal to the first thickness.

[0016] According to some exemplary embodiments, the refractive index of the material of the metasurface nanorods is greater than the refractive index of the material of the filling layer.

[0017] According to some exemplary embodiments, the refractive index of the material of the metasurface nanorods is greater than or equal to 1.5; and / or,

[0018] The refractive index of the material of the filling layer is greater than or equal to 1 and less than or equal to 1.3.

[0019] According to some exemplary embodiments, the metasurface light splitting structure layer has a deflection phase Ψ d (x, y, λ), the deflection phase Ψ d (x, y, λ) satisfies equation (2):

[0020]

[0021] Among them, θ is the off-axis angle of the light beam with a wavelength of λ on the x-axis, and the x-axis is the transverse coordinate axis in the two-dimensional coordinate system constructed by the plane where the metasurface spectroscopic structure layer is located.

[0022] According to some exemplary embodiments, the orthographic projection of the supersurface nanorod on the first substrate has a first projection shape, and the first projection shape is at least one of a circle, a square or a rectangle.

[0023] According to some exemplary embodiments, in at least one of the metasurface spectroscopic units, the first projection shapes of the plurality of the metasurface nanocolumns are not completely the same; and the thicknesses of the plurality of the metasurface nanocolumns in the light emitting direction are the same.

[0024] According to some exemplary embodiments, in at least one of the metasurface spectroscopic units, the first projection shapes of the plurality of the metasurface nanocolumns are the same; and the thicknesses of the plurality of the metasurface nanocolumns in the light emitting direction are not completely the same.

[0025] According to some exemplary embodiments, in at least one of the metasurface light splitting and converging structures, the period of the metasurface nanocolumns is ≤λ / 2, wherein λ is the wavelength range of light transmitted by the metasurface light splitting and converging structure.

[0026] According to some exemplary embodiments, the metasurface spectroscopic structure layer further includes a base portion, and the plurality of metasurface spectroscopic units are located on a side of the base portion away from the reflective layer.

[0027] According to some exemplary embodiments, the material of the reflective layer includes Al; and / or,

[0028] The material of the base portion includes SiO2; and / or,

[0029] The material of the super surface nano column includes one of TiO2, SiNx and GaNx.

[0030] According to some exemplary embodiments, the display panel further includes: a common electrode located between the liquid crystal layer and the second substrate; a shading layer located on a side of the reflective layer close to the first substrate; and a driving circuit layer located on a side of the shading layer close to the first substrate.

[0031] In yet another aspect, a projection system is provided, comprising the display panel as described in any one of the above items.

[0032] According to some exemplary embodiments, the projection system further comprises: a light source, a collimating lens, a polarizing plate, a polarizing beam splitter, and a projection lens group;

[0033] The light emitted by the light source passes through the collimating lens, the polarizing plate and the polarization beam splitter in sequence and enters the display panel to form incident light;

[0034] The incident light is reflected, split and focused by the display panel to form outgoing light; and

[0035] The outgoing light passes through the polarization beam splitter and the projection lens group in sequence to form a projection image.

[0036] According to some exemplary embodiments, a divergence angle of the output light of the projection system is less than or equal to 20°.

[0037] According to some exemplary embodiments, the light source includes at least one of a white light LED light source, an RGB LED light source, or a laser diode light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above contents and other purposes, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0039] Figure 1 is a structural block diagram of a projection system according to an embodiment of the utility model;

[0040] Figure 2 is a partial plan view of a projection system according to an embodiment of the utility model;

[0041] Figure 3 is a partial structural schematic diagram of a display panel according to an exemplary embodiment of the utility model;

[0042] Figure 4 is a partial plan view of a metasurface light splitting structure layer according to some exemplary embodiments of the present utility model; Figure 5 is based on Figure 4 A schematic plan view of a single metasurface spectrometer in the middle dashed box area;

[0043] Fig. 6A is a schematic diagram of a partial structure of a metasurface light-splitting structure layer according to some exemplary embodiments of the utility model; Figure 6B is a planar schematic diagram of an orthographic projection of a supersurface nanorod on a first substrate according to some exemplary embodiments of the present utility model;

[0044] Figure 7 is a diagram showing a corresponding relationship between a structural diameter and a phase of a cylindrical nanorod according to an exemplary embodiment of the present utility model;

[0045] Figure 8 is a graph showing the relationship between the response wavelength and light transmittance of a metasurface light-splitting structure layer according to an exemplary embodiment of the present utility model;

[0046] Figure 9A-9C They are respectively plan schematic diagrams of super-surface nanorods responsive to light of different wavelengths according to exemplary embodiments of the present utility model;

[0047] Fig.10 is a schematic plan view of a metasurface light splitting unit according to an exemplary embodiment of the present utility model;

[0048] Fig.11A is a plan view of a red light modulating metasurface light splitting and converging structure included in a single metasurface light splitting unit according to an exemplary embodiment of the present utility model; Fig. 11B is a plan view of a green light modulating metasurface light splitting and converging structure included in a single metasurface light splitting unit according to an exemplary embodiment of the present utility model; Fig. 11C is a plan view of a blue light modulating metasurface light splitting and converging structure included in a single metasurface light splitting unit according to an exemplary embodiment of the present utility model;

[0049] Figure 12A-12L They are respectively partial cross-sectional views of a display panel during processing according to an exemplary embodiment of the present utility model;

[0050] Fig.13 is a processing flow chart of a display panel according to an exemplary embodiment of the present utility model;

[0051] Fig.14 It is a schematic diagram of the structure of a projection system according to some embodiments of the utility model.

[0052] It should be noted that, for the sake of clarity, in the drawings used to describe the embodiments of the present invention, the sizes of layers, structures or regions may be enlarged or reduced, that is, these drawings are not drawn according to the actual scale. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution of the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings of the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the described embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0054] It should be noted that in the drawings, the size and relative size of the elements may be exaggerated for the purpose of clarity and / or description. Thus, the size and relative size of each element are not necessarily limited to the size and relative size shown in the drawings. In the specification and drawings, the same or similar reference numerals indicate the same or similar parts.

[0055] Unless otherwise defined, the technical terms or scientific terms used in this utility model shall have the usual meanings understood by those of ordinary skill in the art. The words "first", "second" and similar words used in this utility model do not indicate any order, quantity or importance, but are only used to distinguish different components. The words "include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0056] In this document, unless otherwise specified, directional terms such as "upper", "lower", "left", "right", "inner", "outer", etc. are used to indicate the orientation or positional relationship based on the drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device, element or component referred to must have a specific orientation, be constructed or operate in a specific orientation. It should be understood that when the absolute position of the described object changes, the relative positional relationship they represent may also change accordingly. Therefore, these directional terms cannot be understood as limiting the present invention.

[0057] It should be noted that, in this article, "the same layer" refers to a layer structure formed by using the same film-forming process to form a film layer for forming a specific pattern, and then using the same mask to pattern the film layer through a single composition process. Depending on the specific pattern, a single composition process may include multiple exposure, development or etching processes, and the specific pattern in the formed layer structure may be continuous or discontinuous. That is, multiple elements, components, structures and / or parts located in the "same layer" are made of the same material and are formed through the same composition process. Usually, multiple elements, components, structures and / or parts located in the "same layer" have approximately the same thickness.

[0058] Those skilled in the art should understand that, in this document, unless otherwise specified, the expression "height" or "thickness" refers to the dimension along the surface of each film layer arranged perpendicular to the display panel or LCOS device, that is, the dimension along the light emitting direction of the display panel or LCOS device, or the dimension along the normal direction of the display panel or LCOS device.

[0059] In this article, directional expressions "first direction", "second direction" and "third direction" are used to describe different directions along the metasurface light splitting unit, for example, the horizontal direction and the vertical direction of the metasurface light splitting unit. It should be understood that such representation is only an exemplary description and not a limitation of the present invention.

[0060] The term "approximately" in the present invention means that the limits are not strictly defined and the numerical value is allowed to be within the range of process and measurement errors.

[0061] Unless otherwise specified, the relevant terms appearing in this article can be interpreted as follows.

[0062] Metasurface: An electromagnetic wave modulation device constructed by a unit structure of a high refractive index material or metal material whose scale is smaller than the wavelength. It can achieve a variety of electromagnetic wave corresponding effects by using the arrangement design of related unit structures. For example, it can achieve phase deflection or focusing of light of different wavelengths.

[0063] LCOS (Liquid Crystal On Silicon) device: It is one of the key technologies of reflective liquid crystal projectors and rear projection TVs. Its structure is to use semiconductor processes to make a driving panel (also known as a CMOS substrate) on a silicon wafer, then grind it flat through grinding technology and coat it with a reflective layer (such as aluminum) as a reflector to form a CMOS substrate. The CMOS substrate is then bonded to a glass substrate containing a transparent electrode to form an LCOS device.

[0064] In a display formed by using LCOS devices, a driving CMOS substrate (including a CMOS structure of source, gate, drain and storage capacitor, a light shielding layer and a reflective layer) formed by a semiconductor process is bonded to a liquid crystal box containing a transparent electrode to achieve a reflective display. Compared with a traditional transmissive liquid crystal display, since the driving circuit is placed under the pixel opening without blocking the pixel opening, the reflective display device has a higher pixel opening ratio, thereby bringing higher light efficiency.

[0065] In order to achieve color projection, in the relevant technology, LCOS projection schemes mainly include three categories: (1) a single-chip LCOS projection scheme constructed using an LCOS device with a color film; (2) a single-chip LCOS projection scheme constructed using a single LCOS device without a color film and a color wheel for time-domain RGB color separation; (3) a three-chip LCOS projection scheme constructed using three LCOS devices without a color film and a combination of RGB light splitting and beam combining paths. Among them, the light efficiency loss caused by the absorption color film (the light efficiency is only about 30%) leads to low light efficiency of the single-chip color film LCOS projection scheme. The single-chip LCOS scheme without a color film uses a color wheel to select colors, which will also lead to degradation of the display effect and light efficiency loss due to the influence of frame rate. The overall volume of the three-chip LCOS projection system is large, which is not conducive to the miniaturization of the device. The color selection process of the dichroic mirror will also cause a certain amount of light efficiency loss.

[0066] In an embodiment of the utility model, a display panel is provided. The display panel includes: a first substrate; a second substrate arranged opposite to the first substrate; a liquid crystal layer arranged between the first substrate and the second substrate; a reflective layer arranged on the side of the first substrate facing the second substrate; and a super-surface spectroscopic structure layer arranged on the side of the reflective layer away from the first substrate. The super-surface spectroscopic structure layer includes a plurality of periodically arranged super-surface spectroscopic units, and at least one super-surface spectroscopic unit includes a plurality of super-surface spectroscopic convergence structures. Among them, the super-surface spectroscopic unit is used to: separate the white light reflected by the reflective layer into a plurality of monochromatic lights, and respectively converge the plurality of monochromatic lights to the areas where the plurality of sub-pixels of the display panel are located through the super-surface spectroscopic convergence structure. Exemplarily, the display panel can be a display panel including an LCOS device.

[0067] By adopting the metasurface spectroscopic structure layer and utilizing the wavelength dependence and phase superposition function of the metasurface structure, the white light beam is focused and deflected to different angles with red, green and blue light after reflection, realizing color reflective display without color film. Compared with the light efficiency loss caused by the absorption color film, it solves the shortcoming of insufficient light efficiency of color LCOS devices and improves the light efficiency by about 3 times. Further combined with the single-chip LCOS projection system of the white light source, it can have a more compact volume than the three-chip projection system.

[0068] Figure 1 It is a structural block diagram of a projection system according to an embodiment of the utility model.

[0069] For example, in the embodiments of the present invention, referring to Figure 1 , the projection system 100 includes a light source 1, a collimating lens 2, a polarizing plate 3, a polarizing beam splitter 4, a display panel 5 and a projection lens group 6. For example, the display panel 5 may include an LCOS device.

[0070] The light emitted by the light source passes through the collimating lens 2, the polarizing plate 3 and the polarizing beam splitter 4 in sequence and enters the display panel 5 to form incident light. The incident light is reflected, split and focused by the display panel 5 to form outgoing light. The outgoing light passes through the polarizing beam splitter 4 and the projection lens group 6 in sequence to form a projected image.

[0071] In some embodiments, the distance between the projected image and the projection lens group 6 in the projection system is between 1 meter and 3 meters, thereby achieving magnified imaging of image information at a certain distance, so that the signal in the display panel 5 is finally projected into the image size required for viewing by the user.

[0072] Figure 2 It is a partial plan view of a projection system according to an embodiment of the utility model.

[0073] For example, in some embodiments of the present invention, referring to Figure 2The projection system 100 may include a display area AA. The projection system further includes a plurality of pixel units PX located in the display area AA, and the plurality of pixel units PX are arrayed along a first direction X and a second direction Y in the display area AA.

[0074] In the embodiment of the present utility model, the display area AA may have various shapes. For example, the display area AA may be provided in various shapes such as a polygon (e.g., a rectangle) of a closed shape including straight edges, a circle, an ellipse, etc. including curved edges, and a semicircle, a semiellipse, etc. including straight edges and curved edges. In the embodiment of the present utility model, the display area AA is provided as an area having a quadrilateral shape including straight edges, and it should be understood that this is only an exemplary embodiment of the present utility model, and not a limitation of the present utility model.

[0075] The pixel unit PX is the smallest unit for displaying an image. The pixel unit PX may be provided in plurality, arranged in a matrix along rows extending in a first direction X and columns extending in a second direction Y. However, the embodiments of the present invention do not specifically limit the arrangement form of the pixel unit PX, and the pixel unit PX may be arranged in various forms. For example, the pixel unit PX may be arranged such that a direction inclined relative to the first direction X and the second direction Y becomes a column direction, and a direction intersecting the column direction becomes a row direction.

[0076] A pixel unit PX may include a plurality of sub-pixels. For example, a pixel unit PX may include three sub-pixels, namely, a first sub-pixel sp1, a second sub-pixel sp2, and a third sub-pixel sp3. For example, the first sub-pixel sp1 emits red light, the second sub-pixel sp2 emits green light, and the third sub-pixel sp3 emits blue light. It should be understood that this is only an exemplary embodiment of the present invention, and not a limitation of the present invention.

[0077] Figure 3 It is a schematic diagram of a partial structure of a display panel according to an exemplary embodiment of the present utility model.

[0078] For example, in some embodiments of the present invention, referring to Figure 3 The display panel 5 may include: a first substrate 51 , a second substrate 60 disposed opposite to the first substrate 51 , and a liquid crystal layer 57 disposed between the first substrate 51 and the second substrate 60 .

[0079] In some embodiments, the first substrate 51 may include a silicon-based substrate. Accordingly, the display panel 5 may be an LCOS device. It should be understood that in the embodiments of the present utility model, the structure of the display panel is described by taking the LCOS device as an example, but the display panel provided by the embodiments of the present utility model may not be limited to the LCOS device. For example, the first substrate 51 may include a base substrate of an array substrate of a conventional liquid crystal display panel.

[0080] In some embodiments, the second substrate 60 may include a glass substrate.

[0081] For example, continue to refer to Figure 3 The display panel 5 may further include a first alignment layer 56 and a second alignment layer 58. The second alignment layer 58 is located on a side of the liquid crystal layer 57 close to the second substrate 60, and the first alignment layer 56 is located on a side of the liquid crystal layer 57 away from the second substrate 60.

[0082] In some embodiments, the material of the first alignment layer 56 and the second alignment layer 58 may be polyimide (PI).

[0083] For example, continue to refer to Figure 3 The display panel 5 may further include a reflective layer 54 disposed on the side of the first substrate 51 facing the second substrate 60 and a metasurface light-splitting structure layer 55 disposed on the side of the reflective layer 54 away from the first substrate 51 .

[0084] For example, Figure 4 As shown, the metasurface light splitting structure layer 55 may include a plurality of metasurface light splitting units 500 arranged periodically. Figure 3 At least one metasurface light splitting unit 500 includes multiple metasurface light splitting and converging structures, for example, a red light modulating metasurface light splitting and converging structure 501, a green light modulating metasurface light splitting and converging structure 502, and a blue light modulating metasurface light splitting and converging structure 503.

[0085] Exemplarily, in an embodiment of the utility model, the area where the periodically arranged multiple metasurface spectroscopic units 500 are located can be used as the area where the periodically arranged multiple pixel units are located. It should be understood that the pixel unit PX can be set in a one-to-one correspondence with the metasurface spectroscopic unit 500. The area where the multiple metasurface spectroscopic convergence structures are located can be used as the area where the multiple sub-pixels are located. It should be understood that the sub-pixels can be set in a one-to-one correspondence with the metasurface spectroscopic convergence structures. For example, the area where the red light modulating metasurface spectroscopic convergence structure 501 is located can be used as the area where the red sub-pixel R is located, the area where the green light modulating metasurface spectroscopic convergence structure 502 is located can be used as the area where the green sub-pixel G is located, and the area where the blue light modulating metasurface spectroscopic convergence structure 503 is located can be used as the area where the blue sub-pixel B is located.

[0086] In the area where the pixel unit is located, the metasurface light splitting unit 500 processes the input white light to separate multiple monochromatic lights, and respectively converges the separated multiple monochromatic lights to the areas where different sub-pixels are located. Further, the converged monochromatic lights are emitted through the liquid crystal layer to form an image signal.

[0087] For example, the metasurface light splitting unit 500 is used to separate the white light reflected by the reflective layer 54 into a plurality of monochromatic lights, and converge the monochromatic lights to the regions where the different sub-pixels are located through the metasurface light splitting and converging structure. For example, the separated red light is converged to the region where the red sub-pixel R is located through the red light modulating metasurface light splitting and converging structure 501. The separated green light is converged to the region where the green sub-pixel G is located through the green light modulating metasurface light splitting and converging structure 502. The separated blue light is converged to the region where the blue sub-pixel B is located through the blue light modulating metasurface light splitting and converging structure 503.

[0088] Exemplarily, the orthographic projection of the metasurface light-splitting structure layer 55 on the first substrate 51 falls within the orthographic projection of the reflective layer 54 on the first substrate 51. Through the design of the reflective layer, at least most of the incident light can be reflected into the metasurface light-splitting structure layer 55, and then enter the area where the corresponding sub-pixel is located through the phase deflection and focusing effect of the metasurface light-splitting structure layer 55.

[0089] In some embodiments, the material of the reflective layer may include aluminum.

[0090] In some exemplary embodiments, in order to achieve color display, the incident light needs to be separated into red, green and blue light after passing through the metasurface light splitting structure layer 55 and converged into the area where the corresponding sub-pixel is located. A liquid crystal layer 57 is provided on the side of the metasurface light splitting structure layer 55 close to the second substrate 60. By controlling the state of the liquid crystal in the liquid crystal layer 57, the transmittance of light in the area where the sub-pixel is located in the liquid crystal layer can be controlled, thereby achieving the display of different pictures. For example, in combination with reference Figure 3 and Fig.14 After the light in the area where the sub-pixel is located passes through the liquid crystal layer, it can form a projection image under the action of the external projection lens.

[0091] In some embodiments, continue to refer to Figure 3The display panel 5 may further include a common electrode 59 located between the liquid crystal layer 57 and the second substrate 60. For example, the material of the common electrode 59 may include a transparent electrode material, such as ITO. The display panel 5 may further include a light shielding layer 53 located on a side of the reflective layer 54 close to the first substrate. The display panel 5 may further include a driving circuit layer 52 located on a side of the light shielding layer 53 close to the first substrate. The driving circuit layer 52 may include at least one transistor. For example, the transistor may include a gate 521, a source 522, a drain 523, and an active layer 524. The driving circuit layer 52 may further include at least one capacitor 525.

[0092] Exemplarily, the light shielding layers 53 may be arranged at intervals to reduce the amount of light that enters the underlying driving circuit layer, which is beneficial to improving the stability of the driving circuit.

[0093] Exemplarily, the driving circuit layer 52 and the common electrode 59 can be electrically connected to an external driving chip. The voltage between the common electrode 59 and the driving circuit layer 52 is controlled by the signal of the external driving chip, thereby controlling the state of the liquid crystal in the liquid crystal layer 57 between the common electrode 59 and the driving circuit layer 52. By controlling the deflection of the liquid crystal in the liquid crystal layer 57, the transmittance of the area where the corresponding sub-pixel is located can be adjusted, so that the light in the area where each sub-pixel is located can achieve different degrees of transmittance in the liquid crystal layer, thereby realizing different grayscales and different pictures to be displayed externally.

[0094] Figure 4 is a partial plan view of a metasurface light splitting structure layer according to some exemplary embodiments of the present utility model; Figure 5 is based on Figure 4 A schematic plan view of a single metasurface spectrometer in the middle dashed box area; Fig. 6A is a schematic diagram of a partial structure of a metasurface light-splitting structure layer according to some exemplary embodiments of the utility model; Figure 6B It is a plan schematic diagram of the orthographic projection of a supersurface nanorod on a first substrate according to some exemplary embodiments of the present utility model.

[0095] In some embodiments, in conjunction with reference Figure 3-6A The metasurface spectroscopic unit 500 includes a plurality of periodically arranged metasurface nanorods 551 and a filling layer 552 filled in the gaps between the plurality of metasurface nanorods.

[0096] In some embodiments, the refractive index of the material of the metasurface nanorods 551 is greater than the refractive index of the material of the filling layer 552 .

[0097] In some embodiments, the refractive index of the material of the metasurface nanorods 551 is greater than or equal to 1.5.

[0098] In some embodiments, the material of the metasurface nanorods 551 includes high refractive index materials such as silicon nitride, gallium nitride, and titanium oxide.

[0099] In some embodiments, the refractive index of the material of the filling layer 552 is greater than or equal to 1 and less than or equal to 1.3. For example, the material of the filling layer 552 may include a filling glue with a low refractive index, such as a filling glue with a refractive index of 1.3.

[0100] Exemplarily, the supersurface nanocolumn is a rotationally symmetric columnar structure.

[0101] In some embodiments, reference Fig. 6A The orthographic projection of the supersurface nanocolumn on the first substrate has a first projection shape, and the first projection shape can be a circle.

[0102] In other embodiments, referring to Figure 6B The first projection shape m1 can be at least one of a circle, a square or a rectangle.

[0103] Exemplarily, the height of the supersurface nanorod along the third direction Z is H, and the third direction Z is perpendicular to both the first direction X and the second direction Y. Alternatively, the third direction Z is the direction from the first substrate 51 to the second substrate 60 , that is, the light emitting direction.

[0104] The first projection shape of the supersurface nanocolumn and the height H of the supersurface nanocolumn can be specifically designed according to actual needs, and the embodiments of the present utility model do not limit this.

[0105] In some embodiments, all of the metasurface nanorods included in the metasurface light-splitting structure layer are cylindrical nanorods.

[0106] In some embodiments, all of the metasurface nanorods included in the metasurface light-splitting structure layer are square nanorods, such as rectangular nanorods or square nanorods.

[0107] In some embodiments, a portion of all the metasurface nanocolumns included in the metasurface light-splitting structure layer are cylindrical nanocolumns, and another portion are square nanocolumns.

[0108] For example, in conjunction with reference Figure 3 and Fig. 6A The metasurface light splitting structure layer 55 may further include a base portion 553 . The plurality of metasurface light splitting units 500 are located on a side of the base portion 553 away from the reflective layer 54 . Fig. 6AThe unit period P of a single supersurface nanocolumn is shown. For example, the unit period P of the supersurface nanocolumn is 400 nm. The unit period P may include: the diameter of a single complete supersurface nanocolumn; and the width of half of the filling layer in the filling layer that fills the gap between the supersurface nanocolumn adjacent to the supersurface nanocolumn and the supersurface nanocolumn.

[0109] In some embodiments, the material of the base portion 553 may include silicon oxide.

[0110] It should be noted that in the display panel of the LCOS device provided by the embodiment of the utility model, the super-surface light-splitting structure layer realizes the light splitting of white light, mainly based on the unit structure of the super-surface nano-columns. The arrangement of the super-surface nano-columns is designed so that the super-surface light-splitting and converging structure has a corresponding response wavelength, so that the super-surface light-splitting and converging structure can modulate the light at its response wavelength. Accordingly, by designing the super-surface light-splitting and converging structure layer to include different super-surface light-splitting and converging structures, white light can be divided into red light, blue light and green light. Moreover, the arrangement of the super-surface nano-columns can also be designed to modulate the phase, so that the super-surface light-splitting and converging structure also has the function of focusing lens and deflecting light, thereby realizing that the super-surface light-splitting and converging structure converges the corresponding color light and deflects it to the area where the sub-pixel corresponding to the super-surface light-splitting and converging structure is located.

[0111] In some embodiments, in order to achieve convergence and deflection of light beams of modulated wavelengths, the metasurface spectroscopic structure layer needs to express the phase values ​​of the focusing lens and the deflected light at the corresponding wavelengths. This process can be directly achieved through phase superposition.

[0112] In some embodiments, the metasurface light splitting structure layer has a lens phase Ψ lens (x, y, f, λ). The lens phase indicates that the metasurface light-splitting structure layer can adjust the phase distribution of light waves through the design of metasurface structure units, thereby realizing the manipulation of wavefronts and achieving an effect equivalent to lens focusing. lens (x, y, f, λ) satisfies equation (1):

[0113]

[0114] Wherein, x, y are the coordinate positions of the two-dimensional coordinate system of the plane component where the metasurface spectroscopic structure layer is located. Exemplarily, the two-dimensional coordinate system can be a two-dimensional coordinate system of the plane where the first direction X and the second direction Y are located. λ is the wavelength of light, and f is the focal length of the equivalent lens of the metasurface spectroscopic structure layer. It should be noted that the x-axis of the two-dimensional coordinate system can be parallel to the first direction X, and the y-axis can be parallel to the second direction Y. Alternatively, the x-axis of the two-dimensional coordinate system can have a certain angle with the first direction X, and the y-axis can have a certain angle with the second direction Y.

[0115] Through the design of the metasurface spectroscopic structure layer, a geometric lens modulation effect equivalent to a focal length of f can be achieved.

[0116] For example, refer to Figure 3 The display panel 5 further includes a first alignment layer 56 located between the metasurface light splitting structure layer 55 and the liquid crystal layer 57. The first alignment layer 56 has a first thickness h1.

[0117] In some embodiments, the focal length f of the equivalent lens of the metasurface spectroscopic structure layer is equal to the first thickness h1, so that multiple monochromatic lights can be converged into the partial liquid crystal layer of the corresponding sub-pixel, which is beneficial to increase the light intensity in the color conversion sub-area and improve the display brightness.

[0118] For the off-axis light beam, it is equivalent to the optical element expressing a deflection phase.

[0119] In some embodiments, the metasurface light splitting structure layer has a deflection phase Ψd(x, y, λ). The deflection phase refers to the phase corresponding to the deflection of the propagation direction of the light wave after the light passes through the metasurface light splitting structure layer. The deflection phase Ψd(x, y, λ) satisfies equation (2):

[0120]

[0121] Wherein, θ is the off-axis angle of the light beam with a wavelength of λ on the x-axis. Wherein, the x-axis is the transverse coordinate axis in the two-dimensional coordinate system constructed by the plane where the metasurface light splitting structure layer is located.

[0122] By calculating the deflection angle of the corresponding wavelength, the phase distribution of the off-axis beam deflection device can be obtained.

[0123] By combining the lens phase and off-axis deflection phase of the metasurface, off-axis focusing control of a certain wavelength light beam can be achieved.

[0124] In some embodiments, the phase of the off-axis focusing of the metasurface light splitting structure layer The distribution satisfies:

[0125]

[0126] Among them, the phase of off-axis focusing is the lens phase Ψ lensThe sum of (x, y, f, λ) and the deflection phase Ψd(x, y, λ) can simultaneously reflect the relationship between the focusing and deflection phase of light and the coordinate position of the metasurface nanocolumn, the wavelength of light, the off-axis angle θ, and the focal length f of the equivalent lens. By designing the metasurface spectroscopic structure layer so that it responds to different deflection angles for different wavelengths, it can be achieved that after white light is incident on the metasurface spectroscopic structure layer, different wavelengths are focused off-axis at different angles, thereby achieving the color separation and spectroscopic effect of white light. Therefore, the metasurface spectroscopic structure can achieve a color film filtering effect.

[0127] It should be noted that the off-axis angle θ of the light is determined by (x, y) and the center of the sub-pixel corresponding to the position (x, y).

[0128] It should also be noted that the off-axis focusing phase of the metasurface light splitting structure layer Greater than or equal to 0 and less than or equal to 2π.

[0129] Since the metasurface spectroscopic structure layer includes periodically arranged metasurface nanopillars, the light transmittance of the metasurface spectroscopic structure layer is relatively high. The inventors have found through research that a light transmittance greater than 90% can be achieved. The focusing efficiency of the metasurface spectroscopic convergence structure can reach 80%, and the focusing efficiency of the mixed response device of different metasurface spectroscopic convergence structures in the metasurface structure unit can reach 50-60%. In the LCOS projection scheme using color film filtering, the transmittance of the color film is only 30%, that is, compared with the scheme of setting a color film, the display panel of the LCOS device provided in the embodiment of the present application can greatly improve the light utilization rate.

[0130] In some embodiments, Fig. 6A As shown, the super surface nano column is a cylindrical nano column. The bottom surface of the super surface nano column 551 is arranged on the base portion 553, and the columnar sides of the super surface nano column 551 are all wrapped by the filling layer 552. The refractive index of the material of the super surface nano column 551 is higher than the refractive index of the material of the filling layer 552, so that the white light can be better separated and focused.

[0131] In some embodiments, Figure 4 As shown, the metasurface light splitting structure layer may include a plurality of metasurface light splitting units 500. The plurality of metasurface light splitting units 500 may be arranged in an array.

[0132] In some embodiments, Figure 5As shown, in each metasurface light splitting unit, a plurality of different metasurface light splitting and converging structures are provided, such as a red light modulating metasurface light splitting and converging structure 501, a green light modulating metasurface light splitting and converging structure 502, and a blue light modulating metasurface light splitting and converging structure 503. Each metasurface light splitting and converging structure may include a plurality of metasurface nanopillars 551. Exemplarily, the metasurface nanopillars 551 may be cylindrical nanopillars. The periods of the cylindrical nanopillars may be different. For example, the diameters of different cylindrical nanopillars may not be exactly the same.

[0133] In some embodiments, in at least one metasurface spectroscopic unit, the first projection shapes of multiple metasurface nanocolumns are the same; and the thicknesses of the multiple metasurface nanocolumns in the light emitting direction are not completely the same.

[0134] It should be noted that, "not completely identical" means that at least two are different. For example, among a plurality of different cylindrical nanopillars, at least two cylindrical nanopillars have different diameters. For another example, among a plurality of different square nanopillars, at least two square nanopillars have different heights.

[0135] It should also be noted that the cylindrical nanorods belong to the transmission unit structure. Fig. 6A Only one period of cylindrical nanocolumns is shown in FIG. In a specific implementation, phase modulation can be achieved by changing the radius of the cylindrical nanocolumns or the height of the cylindrical nanocolumns, and the response wavelength of the metasurface light-splitting and focusing structure can be determined by designing the period P of the cylindrical nanocolumns.

[0136] In some embodiments, in each metasurface light splitting unit, in different metasurface light splitting and converging structures, the metasurface nanocolumns may be square nanocolumns, and the periods of the square nanocolumns may be different.

[0137] In some embodiments, the phase of the metasurface nanorods Satisfies the following formula (4):

[0138]

[0139] Among them, n eff is the equivalent refractive index of the metasurface light-splitting and focusing structure, λ is the wavelength range of light that the metasurface light-splitting and focusing structure responds to, and H is the height of the metasurface nanocolumn in the direction perpendicular to the substrate. This shows the phase modulation effect of a single metasurface nanorod on light. It should be noted that the equivalent refractive index n eff It is related to parameters such as the size of the supersurface nanocolumn on a plane parallel to the first substrate (such as the radius or the side length), the refractive index of the material of the supersurface nanocolumn, and the refractive index of the material of the filling layer.

[0140] Exemplarily, the supersurface nanocolumns can be formed by a deposition process or a patterning process, and H can be determined in combination with the manufacturing process capability of the supersurface nanocolumns, such as a thin film deposition process. After H is fixed, the radius of the supersurface nanocolumns can be designed to achieve the desired phase.

[0141] Figure 7 is a diagram showing a corresponding relationship between the diameter and phase of a cylindrical nanorod according to an exemplary embodiment of the present utility model; Figure 8 4 is a relationship diagram between the response wavelength and light transmittance of the metasurface spectroscopic structure layer according to an exemplary embodiment of the present utility model.

[0142] In some embodiments, reference Figure 7 , the metasurface nanocolumn is a cylindrical nanocolumn. The horizontal axis is the diameter of the cylindrical nanocolumn, and the vertical axis is the phase value of light of different wavelengths, and the phase value range is 0-2π. When the height of the cylindrical nanocolumn is fixed, adjusting the diameter of the cylindrical nanocolumn can achieve different phase modulations of light of different wavelengths. For example, Figure 7 The phase expression of a group of cylindrical nanorods with diameters between 90nm and 350nm in the range of 0 to 2π is shown. Since the metasurface spectroscopic structure layer needs to modulate the three wavelengths of RGB, different phase expression values ​​need to be given for the three wavelengths of 450nm / 532nm / 620nm to screen the structure that can achieve the corresponding phase solution.

[0143] In some embodiments, the relationship between the response wavelength and transmittance of the metasurface light-splitting structure layer is as follows: Figure 8 As shown. Among them, the horizontal axis is the wavelength range of light, and the vertical axis is the transmittance of light of different wavelengths in different metasurface light-splitting and convergence structures. The cylindrical nanocolumns designed for a specific wavelength range (i.e., the wavelength range corresponding to the light that needs to be modulated by the metasurface light-splitting and convergence structure) have a relatively higher transmittance within a certain wavelength range, and a low transmittance in the non-designed wavelength range. Therefore, according to the wavelength sensitivity of the cylindrical nanocolumns, the red light modulating metasurface light-splitting and convergence structure, the blue light modulating metasurface light-splitting and convergence structure, and the green light modulating metasurface light-splitting and convergence structure are combined to achieve the wavelength modulation effect under white light incident conditions.

[0144] Figure 9A-9C They are respectively plan schematic diagrams of metasurface nanocolumns responsive to light of different wavelengths according to exemplary embodiments of the present invention.

[0145] In some embodiments, in each metasurface light splitting and converging structure, the period P of the metasurface nanocolumns is ≤λ / 2, where λ is the wavelength range of the light modulated by the metasurface light splitting and converging structure. This ensures the accuracy of the light modulation by the metasurface light splitting and converging structure, and avoids converging light that does not correspond to the color to the area where the sub-pixel is located.

[0146] Exemplarily, the period of the cylindrical nanocolumns in the red light modulating metasurface light splitting and converging structure is 300 nanometers (nm), the period of the cylindrical nanocolumns in the blue light modulating metasurface light splitting and converging structure is 200nm, and the period of the cylindrical nanocolumns in the green light modulating metasurface light splitting and converging structure is 250nm. The height of the cylindrical nanocolumns in the direction perpendicular to the substrate is H=850nm. The radius of the cylindrical nanocolumns can be screened according to the wavelengths of red light, green light, and blue light, and a structural group that realizes 2π phase modulation can be constructed.

[0147] For example, the period of the metasurface light splitting unit is 9 microns, which meets the size of a group of RGB pixels. When a group of RGB pixels is split, the focal length is 25 microns (i.e., the thickness of the first alignment layer 56 in the liquid crystal box), which can better focus the light of the corresponding color and improve the display brightness.

[0148] For example, the wavelength of red light is 620nm, the wavelength of green light is 532nm, and the wavelength of blue light is 450nm. The required deflection angles of RGB are -7°, 0°, and 7°, respectively, to ensure that the RGB light beams are controlled on and off by the corresponding liquid crystal pixel switches after separation.

[0149] In specific implementation, the following equations can be used to design the wavelengths of red light, green light, and blue light, the period and phase of the cylindrical nanorods: Fig.9A The red light modulating metasurface light splitting and focusing structure shown in Fig. 9B The green light modulating metasurface light splitting and focusing structure shown in FIG. Fig. 9C The blue light modulating metasurface light splitting and focusing structure shown.

[0150] In order to use the metasurface spectroscopic unit structure for phase expression, the phase corresponding to different colors of light is gridded and discretely calculated according to the unit period size of the metasurface spectroscopic unit structure group, and the phase is folded by taking the remainder of 2π (that is, the phase value is classified into the range of 0 to 2π). Then, the adjacent assignment that conforms to the number of metasurface unit structure groups is performed (taking the unit structure group with 8 phases covering 2π as an example, the phase after grid partition is classified into 1 / 4π, 1 / 2π, 3 / 4π, π, 5 / 4π, 3 / 2π, 7 / 4π and 2π), and finally expressed by the corresponding metasurface unit structure.

[0151] For example, taking the central 4×4 area as an example, the structure coordinate distribution is shown in Table 1, the corresponding point phase values ​​are shown in Table 2, and the corresponding nanocolumn structure radius is shown in Table 3.

[0152] Table 1: Coordinate values ​​of the 4×4 unit structure of the center of the metasurface spectroscopic unit corresponding to a group of pixels (unit: um)

[0153] (-0.6，0.6) (-0.2，0.6) (0.2，0.6) (0.6，0.6) (-0.6，0.2) (-0.2，0.2) (0.2，0.2) (0.6，0.2) (-0.6，-0.2) (-0.2，-0.2) (0.2，-0.2) (0.6，-0.2) (-0.6，-0.6) (-0.2，-0.6) (0.2，-0.6) (0.6，-0.6)

[0154] Table 2: Phase values ​​of the 4×4 unit structure at the center of the metasurface spectroscopic unit corresponding to a group of pixels (unit: π)

[0155] R G B R G B R G B R G B 1.75 1.875 0.125 1.875 1.875 0 0 1.875 1.875 0.125 1.875 1.625 1.75 1.875 0.125 1.875 1.875 0 0 1.875 1.875 0.125 1.875 1.625 1.75 1.875 0.125 1.875 1.875 0 0 1.875 1.875 0.125 1.875 1.625 1.75 1.875 0.125 1.875 1.875 0 0 1.875 1.875 0.125 1.875 1.625

[0156] Table 3: Radius of the 4×4 unit structure at the center of the metasurface spectroscopic unit corresponding to a group of pixels (unit: nm)

[0157] 85 85 85 137.5 85 85 85 137.5 85 85 85 137.5 85 85 85 137.5

[0158] Fig.10 It is a schematic plan view of a metasurface spectrometer unit according to an exemplary embodiment of the present utility model.

[0159] For example, according to the coordinate positions in Table 1, combined with the calculation of formula (3), folded into the range of 2π, the phase values ​​shown in Table 2 can be obtained. Fig. 6A The unit structure of the supersurface nanocolumn shown in the figure makes the unit structure meet the phase modulation requirements of the RGB band under this condition, and the structural radius of the supersurface nanocolumn at the corresponding coordinate position is obtained as shown in Table 3. Finally, the coordinate position in Table 1 and the structural radius of the supersurface nanocolumn in Table 3 are combined to obtain Fig.10 The schematic diagram of the local structural arrangement of the metasurface light-splitting structure layer shown is shown. It should be understood that this is only an exemplary embodiment of the present utility model, rather than a limitation of the present utility model.

[0160] In some embodiments, as shown in Tables 1-3 and Fig.10 As shown in FIG. 1 , by determining the coordinate position of the center of the metasurface spectroscopic unit and combining it with formula (3), the phase expression of different metasurface spectroscopic units for light of different wavelengths can be calculated. Then, only the diameter of the metasurface nanocolumn can be adjusted (e.g. Fig.10 As shown), the phase expression of the metasurface nanocolumns for light of different wavelengths is adjusted to achieve the separation and focusing of light of different wavelengths, so that light of different colors can be separated and focused to the areas where different sub-pixels are located.

[0161] In some embodiments, the positions of different metasurface nanopillars can be adjusted to separate and converge different colors of light to different sub-pixel areas. Figure 5 As shown, each metasurface light-splitting and converging structure includes a plurality of metasurface nanopillars periodically arranged into a first region 30 with a non-rectangular outline; each metasurface light-splitting unit includes a plurality of first regions 30 that can be spliced ​​into a rectangular region. It should be understood that this is only an exemplary embodiment of the present invention, and not a limitation of the present invention. Fig.11Ais a plan view of a red light modulating metasurface light splitting and converging structure included in a single metasurface light splitting unit according to an exemplary embodiment of the present utility model; Fig. 11B is a plan view of a green light modulating metasurface light splitting and converging structure included in a single metasurface light splitting unit according to an exemplary embodiment of the present utility model; Fig. 11C It is a plan schematic diagram of a blue light modulating metasurface light splitting and converging structure included in a single metasurface light splitting unit according to an exemplary embodiment of the present utility model.

[0162] In some embodiments, the red light modulating metasurface light splitting and converging structure 501 selects the first area 30 corresponding to it as follows: Fig.11A The green light modulating metasurface light splitting and focusing structure 502 selects the first area 30 corresponding to it, which can be as follows: Fig. 11B The blue light modulating metasurface light splitting and focusing structure 503 selects the first area 30 corresponding to it, which can be as follows: Fig. 11C The area shown in the figure is denoted by 303. Fig.11A , Fig. 11B , 11C Splicing, then form Figure 5 An area of ​​a metasurface spectrometer unit is shown, and the metasurface spectrometer unit can separate white light into red light, blue light and green light.

[0163] It should be noted that Figures 11A-11C The above is only a schematic illustration of the arrangement of the metasurface spectrometer units and does not constitute a limitation to this utility model.

[0164] The metasurface light splitting unit in the metasurface light splitting structure layer of the utility model can be calculated and designed according to different designs of pixel size and pixel arrangement combined with the structure, refractive index and other parameters of the metasurface nanocolumns to ensure that the metasurface light splitting structure layer can separate and focus white light, thereby meeting the corresponding display requirements. For example, the diameter of the metasurface nanocolumns at different coordinate positions (such as Fig.10 As shown in the figure), the metasurface light splitting structure layer can separate and focus white light. The diameter and position of the metasurface nanopillars can also be adjusted (as shown in the figure). Figure 5 As shown in the figure), the supersurface light splitting structure layer can separate and focus white light. The supersurface light splitting structure layer can also separate and focus white light by adjusting multiple parameters such as the height, diameter and position of the supersurface nanocolumns. In the supersurface light splitting unit, various arrangements of supersurface nanocolumns that can separate and focus light of different colors are within the protection scope of the present utility model.

[0165] Figure 12A-12LThey are respectively partial cross-sectional views of a display panel during processing according to an exemplary embodiment of the present utility model; Fig.13 is a processing flow chart of a display panel according to an exemplary embodiment of the present utility model.

[0166] Exemplarily, an embodiment of the present invention further provides a method for preparing a display panel. Figure 12A-Figure 13 , the method for preparing the display panel includes the following steps S01 to S11.

[0167] In step S01, refer to Fig. 12A , providing a first substrate 51. For example, the first substrate may be a silicon-based substrate.

[0168] In step S02, refer to Fig. 12B A reflective layer 54 is formed on the first substrate 51. For example, the material of the reflective layer may be aluminum.

[0169] In step S03, refer to Fig. 12C A base portion 553 is formed on a side of the reflective layer 54 away from the first substrate 51. For example, the material of the base portion 553 may be silicon oxide.

[0170] In step S04, refer to Fig.12D , a super-surface light-splitting structure material layer 5510, a first mask layer 70 and an etching glue layer 80 are sequentially formed on the side of the base portion 553 away from the first substrate 51. For example, the material of the super-surface light-splitting structure material layer 5510 can be titanium oxide, the material of the first mask layer 70 can be aluminum, and the material of the etching glue layer 80 can be a special glue for electron beam exposure such as ZEP500.

[0171] In step S05, refer to Fig.12E , a patterning process is performed on the etching glue layer 80 to form a pattern. For example, the pattern in the metasurface light splitting structure layer can be processed on the etching glue layer by electron beam direct writing.

[0172] In step S06, refer to Fig.12F , the pattern on the etching glue layer 80 is transferred to the first mask layer 70 by an etching process, and then the etching glue layer 80 is removed. For example, the pattern on the etching glue layer 80 can be transferred to the first mask layer 70 by a dry etching process.

[0173] In step S07, refer to Figure 12G , continue to use the etching process to transfer the pattern on the first mask layer 70 to the super-surface spectroscopic structure material layer 5510, remove the first mask layer 70, and obtain a plurality of super-surface nano-pillars 551.

[0174] In step S08, refer to Fig.12HA low-refractive-index glue is filled in the gaps between the plurality of metasurface nanocolumns 551 as a filling layer 552 of the plurality of metasurface structure units to form a metasurface spectroscopic structure layer 55, thereby forming a first part P1 including a first substrate 51, a reflective layer 54 and a metasurface spectroscopic structure layer 55.

[0175] The method further comprises:

[0176] In step S09, refer to Fig.12I , providing a second substrate 60.

[0177] In step S10, refer to Fig.12J , a liquid crystal cell 530 is formed on the second substrate 60 to form a second portion P2 including the second substrate 60 and the liquid crystal cell 530. The liquid crystal cell 530 may include: a second alignment layer 58, a liquid crystal layer 57, and a first alignment layer 56. The second alignment layer 58 is located on a side of the liquid crystal layer 57 close to the second substrate 60, and the first alignment layer 56 is located on a side of the liquid crystal layer 57 away from the second substrate 60.

[0178] In step S11, refer to Figure 12K , aligning and bonding the first part P1 and the second part P2 to form a display panel including, for example, an LCOS device.

[0179] For example, refer to Figure 12L In an embodiment of the utility model, the method for preparing a display panel may further include: before forming a reflective layer 54 on the first substrate 51, forming a driving circuit layer 52 on the first substrate; and before forming a liquid crystal box 530 on the second substrate 60, forming a common electrode 59 on the second substrate 60.

[0180] Fig.14 It is a schematic diagram of the structure of a projection system according to some embodiments of the utility model.

[0181] Optionally, the embodiment of the present utility model further provides a projection system 100. Fig.14 , the projection system may include the above-mentioned display panel 5. By loading pixel switches and grayscale signals on the common electrodes on the driving circuit layer and the liquid crystal box, the display panel realizes the color separation conversion of the white light source to RGB light, and finally outputs a color image signal. It should be understood that the projection system has the same beneficial effects as the display panel provided in the above-mentioned embodiment.

[0182] The projection system may further include a light source 1 , a collimating lens 2 , a polarizing plate 3 , a polarizing beam splitter 4 and a projection lens group 6 .

[0183] Exemplarily, the light source 1 may be a white light source. For example, the light source 1 includes at least one of a white light LED light source, an RGB LED light source, or a laser diode light source. For example, the spectral band of the light source may include a band of a mixed spectrum composed of various colors of light required by the projection system.

[0184] In some embodiments, the collimating lens 2 can collimate the light source to ensure that the divergence angle of the subsequent projection light path is less than or equal to 20°. For example, the divergence angle of the output light of the projection system is less than or equal to 20°.

[0185] In some embodiments, the polarizer 3 can polarize the light source to achieve beam splitting and meet the liquid crystal regulation requirements.

[0186] In some embodiments, the polarization beam splitter 4 can realize the light path steering of the white light source and the modulated image information.

[0187] In some embodiments, the projection lens group 6 can realize magnified imaging of image information at a certain distance, so that the signal in the display panel is finally projected into an image size that people need to watch.

[0188] Although some embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined by the claims and their equivalents.

Claims

1. A display panel, characterized in that: include: a first substrate; a second substrate disposed opposite to the first substrate; a liquid crystal layer disposed between the first substrate and the second substrate; A reflective layer disposed on a side of the first substrate facing the second substrate; and A metasurface light splitting structure layer is arranged on a side of the reflective layer away from the first substrate, wherein the metasurface light splitting structure layer comprises a plurality of metasurface light splitting units arranged periodically, and at least one of the metasurface light splitting units comprises a plurality of metasurface light splitting and converging structures. Among them, the super-surface spectroscopic unit is used to: separate the white light reflected by the reflective layer into multiple monochromatic lights, and converge the multiple monochromatic lights to the areas where multiple sub-pixels of the display panel are located through the super-surface spectroscopic convergence structure.

2. The display panel according to claim 1, wherein: The orthographic projection of the metasurface light-splitting structure layer on the first substrate falls within the orthographic projection of the reflective layer on the first substrate.

3. The display panel according to claim 1 or 2, wherein: The metasurface spectroscopic unit comprises a plurality of periodically arranged metasurface nanocolumns and a filling layer filled in the gaps between the plurality of metasurface nanocolumns, wherein the metasurface nanocolumns are rotationally symmetric columnar structures.

4. The display panel according to claim 1 or 2, wherein: The metasurface light splitting structure layer has a lens phase , the lens phase Satisfies equation (1): （1）； Wherein, x, y are the coordinate positions in the two-dimensional coordinate system constructed by the plane where the metasurface light-splitting structure layer is located, λ is the wavelength of light, and f is the focal length of the equivalent lens of the metasurface light-splitting structure layer; The display panel further includes a first alignment layer located between the metasurface light-splitting structure layer and the liquid crystal layer, the first alignment layer having a first thickness, wherein the focal length f of the equivalent lens is equal to the first thickness.

5. The display panel according to claim 3, wherein: The refractive index of the material of the supersurface nanorods is greater than the refractive index of the material of the filling layer.

6. The display panel according to claim 3, wherein: The refractive index of the material of the supersurface nanorods is greater than or equal to 1.5; and / or, The refractive index of the material of the filling layer is greater than or equal to 1 and less than or equal to 1.

3.

7. The display panel according to any one of claims 1, 2, 5 and 6, wherein: The metasurface light splitting structure layer has a deflection phase , the deflection phase Satisfies equation (2): （2）； Wherein, θ is the off-axis angle of the light beam with a wavelength of λ on the x-axis, wherein the x-axis is the transverse coordinate axis in the two-dimensional coordinate system constructed by the plane where the metasurface spectroscopic structure layer is located.

8. The display panel according to claim 3, wherein: The orthographic projection of the supersurface nanocolumn on the first substrate has a first projection shape, and the first projection shape is at least one of a circle, a square or a rectangle.

9. The display panel according to claim 8, wherein: In at least one of the metasurface spectroscopic units, the first projection shapes of the plurality of metasurface nanocolumns are not completely the same; and the thicknesses of the plurality of metasurface nanocolumns in the light emitting direction are the same.

10. The display panel according to claim 8, wherein: In at least one of the metasurface spectroscopic units, the first projection shapes of the plurality of metasurface nanocolumns are the same; and the thicknesses of the plurality of metasurface nanocolumns in the light emitting direction are not completely the same.

11. The display panel according to claim 3, wherein: In at least one of the metasurface light splitting and converging structures, the period of the metasurface nanocolumns is ≤λ / 2, wherein λ is the wavelength range of light transmitted by the metasurface light splitting and converging structure.

12. The display panel according to any one of claims 1, 2, 5, 6 and 8-11, wherein: The metasurface light-splitting structure layer also includes a base portion, and a plurality of the metasurface light-splitting units are located on a side of the base portion away from the reflective layer.

13. The display panel according to claim 12, wherein: The material of the reflective layer includes Al; and / or, The material of the base portion includes SiO2; and / or, The metasurface spectroscopic unit includes a plurality of periodically arranged metasurface nanocolumns, and the material of the metasurface nanocolumns includes one of TiO2, SiNx, and GaNx.

14. The display panel according to any one of claims 1, 2, 5, 6, 8-11 and 13, wherein: The display panel further includes: a common electrode located between the liquid crystal layer and the second substrate; a light shielding layer located on a side of the reflective layer close to the first substrate; and a driving circuit layer located on a side of the light shielding layer close to the first substrate.

15. A projection system, characterized in that: The projection system comprises a display panel as claimed in any one of claims 1 to 14.

16. The projection system of claim 15, wherein: The projection system also includes: a light source, a collimating lens, a polarizing plate, a polarizing beam splitter and a projection lens group; The light emitted by the light source passes through the collimating lens, the polarizing plate and the polarization beam splitter in sequence and enters the display panel to form incident light; The incident light is reflected, split and focused by the display panel to form outgoing light; and The outgoing light passes through the polarization beam splitter and the projection lens group in sequence to form a projection image.

17. The projection system according to claim 15 or 16, wherein: The divergence angle of the output light of the projection system is less than or equal to 20°.

18. The projection system of claim 16, wherein: The light source includes at least one of a white light LED light source, an RGB LED light source or a laser diode light source.

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