Display panel, preparation method and application thereof, and AR near-to-eye display device

Abstract

The invention relates to a display panel, a preparation method and application thereof and an AR near-to-eye display device. The display panel comprises a substrate, a light-emitting pixel and a metasurface structure layer which are sequentially stacked, the metasurface structure layer is arranged on the light-emitting side of the light-emitting pixel, and the metasurface structure layer is configured to perform phase modulation on a first light beam emitted from the light-emitting pixel to the metasurface structure layer. Therefore, the second light beam emitted from the metasurface structure layer has collimation and directionality. Wherein the light-emitting pixel comprises sub-pixels of three colors to emit RGB three-color light, the metasurface structure layer comprises three metasurface units, the sub-pixels and the metasurface units are attached in a one-to-one alignment mode, and each metasurface unit conducts phase modulation on light of one color. The display panel can be applied to naked eye 3D light field display, the super-surface structure layer not only realizes collimation and directionality of emergent light of the display panel and improves light efficiency and brightness, but also is favorable for realizing light and thin display panel.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a display panel and a method for preparing the same, applications of the display panel, and an AR near-eye display device. Background Art

[0002] Display pixels typically have a Lambertian emission pattern, including standard light-emitting diode (LED) dies such as Micro LEDs, as well as organic light-emitting diodes (OLEDs) and silicon-based OLEDs, and this feature is independent of wavelength. For some display applications, light with collimated and directional emission may be beneficial or necessary. For example, light emitted from infrared (IR) LEDs for iris scanning needs to be collimated; OLEDs and quantum dot LEDs have low light extraction efficiency and also require microlenses to focus to increase pixel brightness; naked-eye 3D light field displays require that the light of each pixel be directed to the human eye to form discrete viewpoints, which involves light collimation and directional emission.

[0003] For naked-eye light field 3D display, a cylindrical lens array or a micro lens array is usually used to achieve directional light emission. This type of lens uses the principle of geometric optics, generally requires a large volume and thickness, and due to poor directivity, the display effect has large aberrations and crosstalk. Summary of the invention

[0004] The present invention provides a display panel and a preparation method and application thereof, and an AR near-eye display device, so as to solve the technical problems that for naked-eye light field 3D display, the optical machine generally requires a large volume and thickness, and the light output directionality of the optical machine is poor, resulting in a large phase difference and crosstalk in the display effect.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a display panel, comprising: substrate; A plurality of light-emitting pixels are disposed on one side of the substrate, and the light-emitting pixels emit RGB three-color light; A metasurface structure layer is provided on the light-emitting side of the light-emitting pixel, and the metasurface structure layer is configured to phase-modulate a first light beam emitted from the light-emitting pixel to the metasurface structure layer, so that a second light beam emitted from the metasurface structure layer has collimation and directionality; The luminous pixel includes sub-pixels of three colors, the metasurface structure layer includes a plurality of metasurface units arranged in an interval array and having three different phases, and the sub-pixels of the three colors are aligned with the metasurface units of the three phase structures one by one, so that the metasurface unit corresponding to one phase structure performs phase modulation on light of one color; the metasurface unit performs phase modulation on the light emitted by the corresponding sub-pixel, satisfying the following formulas (1) to (3): In formula (1), is the phase delay, is the collimation delay phase; is the phase deflected to different angles; In formula (2), f is the focal length, n is i is the refractive index of the medium through which the light incident on different metasurface units passes. In formula (2) and formula (3), λ represents the wavelength of the corresponding incident light, and x / y / z represents the spatial position coordinates of the metasurface structure; In formula (3), represents the angle between the Z axis and the projection of the deflected beam in the XZ plane; represents the angle between the Z axis and the projection of the deflected beam in the YZ plane; n o Represents the refractive index of the output medium.

[0006] In one of the embodiments, the display panel includes a microlens array layer, the microlens array layer is stacked on the light emitting surface of the substrate, and the microlens array layer is located between the light emitting pixels and the metasurface structure layer.

[0007] In one of the embodiments, the display panel further includes a protective adhesive layer, which is filled between the super-surface units; and / or, the display panel further includes encapsulation glass, which is stacked on a side of the super-surface structure layer away from the substrate.

[0008] In one embodiment, each of the metasurface units has a cylindrical geometry or a ring geometry.

[0009] In a second aspect, the present invention provides a method for preparing a display panel, comprising the following steps: preparing a substrate, and forming light-emitting pixels on one side of the substrate; Designing a super surface structure layer, wherein the design of the super surface structure layer is based on a coupled wave method and a finite difference time domain method, wherein the coupled wave method is used for unit structure design, and the finite difference time domain method is used for overall structure design and verification; The super surface structure layer is formed on a side of the light emitting pixel away from the substrate, and the super surface structure layer is configured to phase modulate the first light beam emitted from the light emitting pixel to the super surface structure layer, so that the second light beam emitted from the super surface structure layer has collimation and directionality; The luminous pixel includes sub-pixels of three colors, the metasurface structure layer includes a plurality of metasurface units that are spaced and arranged in an array and have three different phases, and the sub-pixels of the three colors are aligned one by one with the metasurface units of the three phase structures, so that the metasurface unit corresponding to one phase structure performs phase modulation on light of one color; the metasurface unit performs phase modulation on the light emitted by the corresponding sub-pixel, satisfying the following formulas (1) to (3): In formula (1), is the phase delay, is the collimation delay phase; is the phase deflected to different angles; In formula (2), f is the focal length, n is i is the refractive index of the medium through which the light incident on the metasurface structure layer passes. In formula (2) and formula (3), λ represents different wavelengths, and x / y / z represents the spatial position coordinates of the metasurface structure; In formula (3), represents the angle between the Z axis and the projection of the deflected beam in the XZ plane; represents the angle between the Z axis and the projection of the deflected beam in the YZ plane; n o Represents the refractive index of the output medium.

[0010] In one embodiment, designing the metasurface structure layer comprises the following steps: Based on the parameters of the luminous pixels, constructing a metasurface structure layer matching the luminous pixels; extracting phase distribution information of the metasurface structure; Discretize the phase distribution information according to the periodic size of the metasurface unit library to obtain a phase discretization result; The metasurface unit structure library corresponds to the luminous spectrum range of the luminous pixel and includes a plurality of metasurface unit structures, each metasurface unit structure corresponds to a phase value in the range of 0 to 2π, and the phase values ​​corresponding to the metasurface unit structures are different; The metasurface unit array is arranged according to the phase discretization results to construct a metasurface structure layer.

[0011] In one embodiment, forming the super surface structure layer comprises the following steps: Depositing a super surface film layer and a hard mask layer in sequence on the light emitting surface of the substrate; Performing patterning and etching on the hard mask layer in sequence to transfer the pattern on the hard mask layer to the super surface film layer; Removing the hard mask layer to form the super surface structure layer; Wherein, the metasurface structure layer includes a plurality of metasurface units matching the wavelengths of RGB three primary colors of light.

[0012] In a third aspect, the present invention provides an application of a display panel, wherein the display panel described in any one of the foregoing embodiments or the display panel manufactured in any one of the method embodiments is applied to naked-eye 3D light field display.

[0013] In a fourth aspect, the present invention provides an AR near-eye display device, comprising: An optical waveguide having an incoupling structure and an outcoupling structure; As for the display panel described in any of the foregoing embodiments or the display panel manufactured by any of the manufacturing methods, the display panel serves as a light source device and is arranged on one side of the coupling-in structure of the optical waveguide, and the light emitted by the display panel enters the optical waveguide through the coupling-in structure and propagates to the coupling-out structure for coupling out.

[0014] In one embodiment, the coupling structure includes a geometric coupling device, and the metasurface structure layer is spaced apart from the geometric coupling device or the metasurface structure layer is attached to a mirror surface of the geometric coupling device.

[0015] It can be seen from the above technical solutions that the embodiments of the present invention have at least the following advantages and positive effects: Embodiments of the present invention relate to a display panel, a preparation method and application thereof, and an AR near-eye display device. The display panel includes a substrate, a light-emitting pixel, and a super-surface structure layer stacked in sequence, the super-surface structure layer is arranged on the light-emitting side of the light-emitting pixel, and the super-surface structure layer is configured to phase-modulate a first light beam emitted from the light-emitting pixel to the super-surface structure layer, so that a second light beam emitted from the super-surface structure layer has collimation and directionality. Specifically, the light-emitting pixel includes sub-pixels of three colors to emit RGB three-color light, and the super-surface structure layer includes three super-surface units, and the sub-pixels of each color are aligned and bonded to different super-surface units one by one, so that each super-surface unit phase-modulates light of one color. On the one hand, the metasurface structure layer realizes the collimation and directionality of the light emitted by the display panel, thereby improving the light efficiency and light brightness and reducing light crosstalk. The above advantages enable the display panel of the present application to achieve better naked-eye 3D light field display; on the other hand, the metasurface structure layer is composed of a group of metasurface unit structures whose scale is smaller than the wavelength of the incident light, which are arranged according to a certain arrangement rule, and the thickness is as small as the micro-nano level, which is conducive to realizing the lightness and thinness of the display panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0017] FIG1 is a schematic diagram of an existing LED display optical path (a) and a schematic diagram of the divergence angle distribution of an LED (b); FIG2 is a schematic diagram of the display optical path of the LED integrated with the microlens array shown in FIG1 (a) and a schematic diagram of the divergence angle distribution of the LED (b); FIG3 is a schematic diagram of an optical path of a display panel (a) and a schematic diagram of the divergence angle distribution of light-emitting pixels (b) according to an embodiment of the present application; Figure 4 It is a schematic diagram of the structure of the display panel shown in FIG3; Figure 5 This is a schematic diagram of an optical path and structure of a display panel according to another embodiment of the present application; Figure 6 This is a flow chart of a method for preparing a display panel according to an embodiment of the present application; Figure 7 for Figure 6 The steps of designing the super surface structure layer in the preparation process shown; Figure 8 for Figure 6The steps of forming the super surface structure in the preparation process shown; Fig. 9 This is a schematic diagram of an optical path and structure of applying a display panel to naked-eye 3D light field display according to an embodiment of the present application; Fig.10 This is a schematic diagram of the optical path and structure of an AR near-eye display device according to an embodiment of the present application; Fig.11 This is a schematic diagram of the optical path and structure of an AR near-eye display device according to another embodiment of the present application.

[0018] The following are the descriptions of the reference numerals: 1. AR near-eye display device; 12. Light source device; 10. Display panel; 100. Substrate; 200. Light-emitting pixel; 201. Red light sub-pixel; 202. Green light sub-pixel; 203. Blue light sub-pixel; 300. Metasurface structure layer; 301. Red light metasurface unit; 302. Green light metasurface unit; 303. Blue light metasurface unit; 400. Microlens structure layer; 500. Protective adhesive layer; 600. Encapsulation glass; 20. Optical waveguide; 21. Coupling structure; 211. Reflector; 212. Prism. DETAILED DESCRIPTION

[0019] Typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various changes in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations therein are essentially used for illustration purposes rather than for limiting the present invention.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0021] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "setting", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0022] Display pixels usually have a Lambertian emission pattern, including standard light-emitting diode (LED) dies such as micro-light-emitting diodes (MicroLEDs), and organic light-emitting diodes (OLEDs) and silicon-based OLEDs, and this feature is independent of wavelength. In some display application scenarios, the light emitted by the light-emitting pixel 200 is required to have collimation and directionality. It should be noted that the collimation of light means that the light beam is modulated from divergent light to a parallel light beam, and the directionality of light means that the light beam is modulated to emit at a preset angle. Figure 1 shows that the current LED pixels usually have a Lambertian emission pattern, and their luminous energy is distributed in a Lambertian type, and the emitted light has neither collimation nor directionality. Figure 2 (a) shows that a microlens array is integrated above the light-emitting pixel to increase the collimation of the light. After adding the microlens array, the collimation is improved, the luminous angle range is reduced, and the brightness of the light is improved, but this method has crosstalk between adjacent pixels and increases the thickness of the display device or the display optical machine itself.

[0023] Therefore, in order to achieve the collimation and directionality of LED pixel light and at the same time meet the requirements of thinning and lightening the display device or display optical machine, the present application provides a display panel 10.

[0024] Combined with reference to Figure 3 and Figure 4 The display panel 10 includes a substrate 100, a light-emitting pixel 200 and a super-surface structure layer 300. The number of the light-emitting pixels 200 is multiple and is arranged on one side of the substrate 100. The light-emitting pixels 200 include but are not limited to light-emitting elements such as LEDs, OLEDs, and quantum dots; the super-surface structure layer 300 is arranged on the light-emitting side of the light-emitting pixel 200. The super-surface structure layer 300 is configured to phase-modulate the first beam of light emitted from the light-emitting pixel 200 to the super-surface structure layer 300, so that the second beam of light emitted from the super-surface structure layer 300 has extremely high collimation and directionality (as shown in Figure 3 (a)). The super-surface structure layer 300 is composed of a super-surface unit structure group whose scale is smaller than the wavelength of the incident light, arranged according to a certain arrangement rule. The super-surface structure layer 300 is usually a micro-nano structure (GaN, TiO, SiN, etc.) built on a substrate material (SiO2, AO3, etc.). The metasurface structure layer 300 can accurately modulate the phase of incident light with its micro-nano structure optical modulation characteristics, thereby achieving precise control of the incident light. It has the characteristics of strong design, small structure size, and precise light control.

[0025] Specifically, in Figure 4In the embodiment, the luminescent pixel 200 includes sub-pixels of three colors, namely, a red sub-pixel 201, a green sub-pixel 202, and a blue sub-pixel 203. The metasurface structure layer 300 is composed of a plurality of metasurface unit arrays, including three metasurface units with different structures, namely, a red metasurface unit 301, a green metasurface unit 302, and a blue metasurface unit 303. The red metasurface unit 301 is aligned with the red sub-pixel 201 one by one, and the red metasurface unit 301 performs phase modulation on the red light emitted by the red sub-pixel 201; the green metasurface unit 302 is aligned with the green sub-pixel 202 one by one, and the green metasurface unit 302 performs phase modulation on the green light emitted by the green sub-pixel 202; the blue metasurface unit 303 is aligned with the blue sub-pixel 203 one by one, and the blue metasurface unit 303 performs phase modulation on the blue light emitted by the blue sub-pixel 203. That is, each metasurface unit of each structure performs phase modulation on light of one color, and each metasurface unit performs phase modulation on the light emitted by the corresponding sub-pixel, satisfying the following formulas (1) to (3): In formula (1), is the phase delay, is the collimation delay phase; is the phase deflected to different angles; In formula (2), f is the focal length, n is i is the refractive index of the medium through which the light incident on different metasurface units passes. In formula (2) and formula (3), λ represents the wavelength of the corresponding incident light, and x / y / z represents the spatial position coordinates of the metasurface structure; In formula (3), represents the angle between the Z axis and the projection of the deflected beam in the XZ plane; represents the angle between the Z axis and the projection of the deflected beam in the YZ plane; n o Represents the refractive index of the output medium.

[0026] Preferably, reference Figure 5 In one embodiment, the display panel 10 may further include a microlens structure layer 400, which is stacked on the light-emitting surface of the substrate 100, and the microlens structure layer 400 is located between the light-emitting pixel 200 and the super-surface structure layer 300. The light emitted by the light-emitting pixel 200 is first regulated by the microlens structure layer 400 to be narrowed into a first beam of light, and then phase-modulated for a second time by the super-surface structure layer 300, so that the light (the second beam of light) has higher collimation and directionality. It should be understood that, without considering the higher collimation and directionality of the light, in this application, whether the microlens structure layer 400 is set or not is not limited.

[0027] Preferably, reference Figure 4 , the super-surface structure layer 300, as a micro-nano structure, is very susceptible to damage if it is directly exposed to the air. Therefore, in order to protect the super-surface structure layer 300, on the one hand, the display panel 10 also includes a protective adhesive layer 500, and the protective adhesive layer 500 is filled between the super-surface units. On the other hand, the display panel 10 also includes an encapsulation glass 600, and the encapsulation glass 600 is stacked and arranged on the side of the super-surface structure layer 300 away from the substrate 100, that is, covering the light-emitting surface of the super-surface structure layer 300. It should be understood that, without considering the need for the super-surface structure layer 300 to be protected, there is no limitation on whether the protective adhesive layer 500 or the encapsulation glass 600 is provided.

[0028] Preferably, each super surface unit has a regular structure such as a columnar geometry or annular geometry, which is conducive to the construction and processing of the super surface structure layer 300 (facilitating array arrangement). It should be noted that the columnar geometry includes but is not limited to a cylinder, a cuboid, and a cube, and the annular geometry includes but is not limited to concentric cylinders. It should be understood that without considering the convenience of the construction and processing of the super surface structure layer 300, in this application, the form and shape of the super surface unit are not limited.

[0029] refer to Figure 6 The present application provides a method for preparing a display panel 10, comprising the following steps: S10, preparing a substrate 100, and forming a plurality of light-emitting pixels 200 on one side of the substrate 100; S20, designing the metasurface structure layer 300. The design of the metasurface structure layer 300 is based on the rigorous coupled wave method (RCWA) and the finite difference time domain method (FDTD), wherein RCWA is used for unit structure design and FDTD is used for overall structure design and verification. The main parameters involved in the design process are: the height of the metasurface structure layer 300, the morphology of a single metasurface unit, which can be a regular structure such as a column or a ring, or a free morphology structure; S30, prepare the display panel 10, form a metasurface structure layer 300 on the side of the luminescent pixel 200 facing away from the substrate 100 (i.e., the light emitting side), and the metasurface structure layer 300 is configured to phase modulate the first beam of light emitted from the luminescent pixel 200 to the metasurface structure layer 300, so that the second beam of light emitted from the metasurface structure layer 300 has extremely high collimation and directionality. The luminescent pixel 200 includes sub-pixels of three colors, and the metasurface structure layer 300 includes a plurality of metasurface units that are spaced and arranged in an array and have three different phase structures. The sub-pixels of the three colors are aligned and bonded to the metasurface units of the three phase structures one by one, so that the metasurface unit corresponding to one phase structure phase modulates the light of one color; the metasurface unit phase modulates the light emitted by the corresponding sub-pixel, satisfying the following formulas (1) to (3): In formula (1), is the phase delay, is the collimation delay phase; is the phase deflected to different angles; In formula (2), f is the focal length, n is i is the refractive index of the medium through which the light incident on different metasurface units passes. In formula (2) and formula (3), λ represents the wavelength of the corresponding incident light, and x / y / z represents the spatial position coordinates of the metasurface structure; In formula (3), represents the angle between the Z axis and the projection of the deflected beam in the XZ plane; represents the angle between the Z axis and the projection of the deflected beam in the YZ plane; n o Represents the refractive index of the output medium.

[0030] refer to Figure 7 In the process of preparing the display panel 10, the specific steps of designing the super surface structure layer are as follows: S21, collimation and deflection phase design, based on the parameters of the luminous pixel, constructing a metasurface structure layer matching the luminous pixel, and extracting phase distribution information of the metasurface structure; S22, phase discretization, discretizing the phase distribution information according to the periodic size of the metasurface unit library to obtain a phase discretization result; S23, constructing a metasurface unit structure library, the metasurface unit structure library corresponds to the luminous spectrum range of the luminous pixel and includes a plurality of metasurface unit structures, each metasurface unit structure corresponds to a phase value in the range of 0 to 2π, and each metasurface unit structure corresponds to a different phase value; S24, constructing a metasurface structure layer, and arranging a metasurface unit array according to the phase discretization result to construct a metasurface structure layer.

[0031] In one embodiment, the phase distribution information is discretized according to the period size of the metasurface unit structure library, including: dividing the phase distribution information with the period of the metasurface unit structure as the minimum division scale, so that the phase distribution information is discretized into phase values ​​within the range of 0 to 2π.

[0032] refer to Figure 8 In the process of preparing the display panel 10, the specific steps of forming the super surface structure layer 300 are as follows: S31, depositing two thin films, sequentially depositing a super-surface material film (which may be SiNx, nano-imprint glue, etc.) and a hard mask film (aluminum Al, titanium Ti, chromium Cr, etc.) on the light-emitting pixel 200 material layer (on the light-emitting surface of the substrate 100); S32, patterning treatment, patterning the hard mask film so that the hard mask film forms a pattern of a super surface structure to form a hard mask layer; S33, etching, using the hard mask layer as a mask to etch the super surface material film to transfer the pattern of the hard mask layer to the super surface material film; S34, cleaning, and then removing the hard mask layer to form a super surface structure layer; The metasurface structure layer 300 includes a plurality of metasurface unit structures that match the wavelengths of RGB three primary color lights.

[0033] Preferably, in this embodiment, the one-to-one alignment of the metasurface unit and the sub-pixel can be performed by using a high-precision alignment and lamination technology to align the metasurface structure layer with the light-emitting pixel. When preparing the light-emitting unit, an alignment mark is simultaneously made, and the alignment mark is referenced during the subsequent processing of the metasurface structure to achieve pixel alignment.

[0034] Thirdly, 3D display is a technology that can display scenes and objects with a sense of depth, allowing observers to directly observe 3D images with physical depth. At present, 3D display technologies mainly include naked-eye and device-assisted display. Among them, naked-eye 3D display technology has attracted much attention because it does not require the assistance of glasses and other devices and is convenient and flexible. Naked-eye 3D display technology is a light field display technology. The encoded light field information is projected to different positions in space through a light field modulation device to form a real 3D light field with continuous parallax at different positions in space, which can provide stereoscopic parallax in multiple directions such as horizontal and vertical directions at the same time. Most traditional naked-eye 3D display devices are based on devices such as lens arrays. They are limited by lens processing technology and refraction modulation models. There is a constraint relationship between their 3D viewing angle, 3D resolution and display depth. They are large in size and have crosstalk, resulting in poor 3D display effects.

[0035] So, reference Fig. 9, the present invention applies the display panel 10 provided in the previous embodiment or the display panel 10 prepared by the preparation method to the naked eye 3D light field display. The substrate 100 and the light-emitting pixel 200 constitute the light source device 12, and the angular spectrum of the light intensity emitted by the light source device 12 follows the Lambertian distribution. The metasurface structure layer 300 is used to collimate and direct the emission of the outgoing light of each light-emitting pixel 200, and the emission direction is determined by the light field modulation rule of the light field display to restore the 3D light field visible to the naked eye. The metasurface structure layer 300 is prepared by electron beam exposure and reactive ion etching based on meta-atoms and phase templates; wherein the light source device 12 and the metasurface structure layer 300 are arranged in sequence on the optical path of the outgoing light. The present invention has the advantages of small size, light weight and low crosstalk, and achieves a better naked eye 3D light field display.

[0036] Fourthly, reference Fig.10 or Fig.11 The present application also provides an AR near-eye display device 1, including an optical waveguide 20 and a display panel 10 in the previous embodiment or a display panel 10 prepared by the preparation method. The optical waveguide 20 has a coupling-in structure 21 and a coupling-out structure. The display panel 10 is a light-emitting device and is arranged on one side of the coupling-in structure 21 of the optical waveguide 20. The light emitted by the display panel 10 enters the optical waveguide 20 through the coupling-in structure 21 and propagates. Among them, the angular spectrum of the light intensity emitted by the display panel 10 follows the Lambertian distribution. The metasurface structure layer 300 collimates and directionally emits the outgoing light of each pixel, and then propagates into the optical waveguide 20 to be coupled out by the coupling-out structure. Therefore, the AR near-eye display device 1 of the present application does not require a lens collimation system, and can achieve more efficient coupling with the optical waveguide. It should be noted that in the present application, the coupling-out structure is not limited, and it only needs to satisfy the coupling-out of the light in the optical waveguide 20.

[0037] Preferably, in this embodiment, the coupling structure 21 is a geometric coupling device, for example, a reflector 211 (such as Fig.10 ) and prism 212 (as Fig.11 As shown in the figure, a geometric optical element for coupling is used. Since the metasurface structure layer 300 is composed of sub-wavelength nano-meta-atoms, its volume is extremely small, and the output light of the metasurface structure layer 300 is pixelated, collimated and deflected light, so there is no need for a traditional lens collimation system, which greatly reduces the overall system volume of the AR near-eye display device 1. In addition, geometric coupling devices such as reflectors 211 can losslessly couple the incident light into the optical waveguide, thereby solving the problem of low overall light energy utilization. It should be noted that when the geometric coupling device is a prism 212, the metasurface structure layer 300 can be attached to the mirror surface of the prism 212, or it can be spaced from the mirror surface of the prism 212. It should be understood that in other embodiments of the present application, the coupling structure 21 can also be a coupling structure such as a diffraction grating.

[0038] The present invention provides a display panel 10, a preparation method and application thereof, and an AR near-eye display device 1. The display panel 10 includes a substrate 100, a light-emitting pixel 200, and a super-surface structure layer 300 stacked in sequence, the super-surface structure layer 300 is arranged on the light-emitting side of the light-emitting pixel 200, and the super-surface structure layer 300 is configured to phase-modulate the first light beam emitted from the light-emitting pixel 200 to the super-surface structure layer 300, so that the second light beam emitted from the super-surface structure layer 300 has collimation and directionality. Specifically, the light-emitting pixel 200 includes sub-pixels of three colors to emit RGB three-color light, and the super-surface structure layer 300 includes three super-surface units, and the sub-pixels of each color are aligned and bonded to different super-surface units one by one, so that each super-surface unit phase-modulates light of one color. On the one hand, the metasurface structure layer 300 realizes the collimation and directionality of the light emitted by the display panel 10, thereby improving the light efficiency and light brightness and reducing light crosstalk. The above advantages enable the display panel 10 of the present application to achieve better naked-eye 3D light field display, so the display panel 10 is applied to naked-eye 3D light field display; on the other hand, the metasurface structure layer 300 is composed of a metasurface unit structure group whose scale is smaller than the wavelength of the incident light, which is arranged according to a certain arrangement rule, and has a small thickness of the micro-nano level, which is conducive to realizing the thinness of the display panel 10.

[0039] Although the present invention has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present invention can be embodied in a variety of forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A display panel, characterized in that: include: substrate; A plurality of light-emitting pixels are disposed on one side of the substrate, and the light-emitting pixels emit RGB three-color light; A metasurface structure layer is provided on the light-emitting side of the light-emitting pixel, and the metasurface structure layer is configured to phase-modulate a first light beam emitted from the light-emitting pixel to the metasurface structure layer, so that a second light beam emitted from the metasurface structure layer has collimation and directionality; The luminous pixel includes sub-pixels of three colors, the metasurface structure layer includes a plurality of metasurface units arranged in an interval array and having three different phase structures, and the sub-pixels of the three colors are aligned with the metasurface units of the three phase structures one by one, so that the metasurface unit corresponding to one phase structure performs phase modulation on light of one color; the metasurface unit performs phase modulation on the light emitted by the corresponding sub-pixel, satisfying the following formulas (1) to (3): In formula (1), is the phase delay, is the collimation delay phase; is the phase deflected to different angles; In formula (2), f is the focal length, n is i is the refractive index of the medium through which the light incident on different metasurface units passes. In formula (2) and formula (3), λ represents the wavelength of the corresponding incident light, and x / y / z represents the spatial position coordinates of the metasurface structure; In formula (3), represents the angle between the Z axis and the projection of the deflected beam in the XZ plane; represents the angle between the Z axis and the projection of the deflected beam in the YZ plane; n o Represents the refractive index of the output medium.

2. The display panel according to claim 1, characterized in that: The display panel includes a microlens array layer, which is stacked on the light-emitting surface of the substrate and located between the light-emitting pixels and the super-surface structure layer.

3. The display panel according to claim 1, characterized in that: The display panel further includes a protective adhesive layer, which is filled between the super-surface units; and / or the display panel further includes encapsulation glass, which is stacked and arranged on a side of the super-surface structure layer away from the substrate.

4. The display panel according to claim 1, characterized in that: Each of the super surface units has a cylindrical geometric shape or a ring geometric shape.

5. A method for preparing a display panel, characterized in that: The steps include: preparing a substrate, and forming light-emitting pixels on one side of the substrate; Designing a super surface structure layer, wherein the design of the super surface structure layer is based on a coupled wave method and a finite difference time domain method, wherein the coupled wave method is used for unit structure design, and the finite difference time domain method is used for overall structure design and verification; The super surface structure layer is formed on a side of the light emitting pixel away from the substrate, and the super surface structure layer is configured to phase modulate the first light beam emitted from the light emitting pixel to the super surface structure layer, so that the second light beam emitted from the super surface structure layer has collimation and directionality; The luminous pixel includes sub-pixels of three colors, the metasurface structure layer includes a plurality of metasurface units that are spaced and arranged in an array and have three different phase structures, and the sub-pixels of the three colors are aligned with the metasurface units of the three phase structures one by one, so that the metasurface unit corresponding to one phase structure performs phase modulation on light of one color; the metasurface unit performs phase modulation on the light emitted by the corresponding sub-pixel, satisfying the following formulas (1) to (3): In formula (1), is the phase delay, is the collimation delay phase; is the phase deflected to different angles; In formula (2), f is the focal length, n is i is the refractive index of the medium through which the light incident on the metasurface structure layer passes. In formula (2) and formula (3), λ represents different wavelengths, and x / y / z represents the spatial position coordinates of the metasurface structure; In formula (3), represents the angle between the Z axis and the projection of the deflected beam in the XZ plane; represents the angle between the Z axis and the projection of the deflected beam in the YZ plane; n o Represents the refractive index of the output medium.

6. The method for preparing a display panel according to claim 5, characterized in that: Designing the metasurface structure layer includes the following steps: Based on the parameters of the luminous pixels, constructing a metasurface structure layer matching the luminous pixels; extracting phase distribution information of the metasurface structure; Discretize the phase distribution information according to the periodic size of the metasurface unit library to obtain a phase discretization result; The metasurface unit structure library corresponds to the luminous spectrum range of the luminous pixel and includes a plurality of metasurface unit structures, each metasurface unit structure corresponds to a phase value in the range of 0 to 2π, and the phase values ​​corresponding to the metasurface unit structures are different; The metasurface unit array is arranged according to the phase discretization results to construct a metasurface structure layer.

7. The method for preparing a display panel according to claim 5, characterized in that: Forming the super surface structure layer comprises the following steps: Depositing a super surface film layer and a hard mask layer in sequence on the light emitting surface of the substrate; Performing patterning and etching on the hard mask layer in sequence to transfer the pattern on the hard mask layer to the super surface film layer; Removing the hard mask layer to form the super surface structure layer; Wherein, the metasurface structure layer includes a plurality of metasurface units matching the wavelengths of RGB three primary colors of light.

8. An application of a display panel, characterized in that: The display panel described in any one of claims 1 to 4 is applied to naked-eye 3D light field display; or the display panel prepared by any one of the preparation methods described in claims 5 to 7 is applied to naked-eye 3D light field display.

9. An AR near-eye display device, characterized in that: include: An optical waveguide having an incoupling structure and an outcoupling structure; The display panel according to any one of claims 1 to 4 or the display panel prepared by the preparation method according to any one of claims 5 to 7, wherein the display panel serves as a light source device and is arranged on one side of the coupling-in structure of the optical waveguide, and the light emitted by the display panel enters the optical waveguide through the coupling-in structure and propagates to the coupling-out structure for coupling out.

10. The AR near-eye display device according to claim 9, characterized in that: The coupling structure includes a geometric coupling device, the metasurface structure layer is spaced apart from the geometric coupling device or the metasurface structure layer is attached to the mirror surface of the geometric coupling device.

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