Disclosure of Invention
The invention provides a display panel, a preparation method and application thereof, and an AR near-to-eye display device, which are used for solving the technical problems that for 3D display of an naked eye light field, an optical machine generally needs larger volume and thickness, and the light-emitting directivity of the optical machine is poor, so that the display effect has larger phase difference and crosstalk.
In order to solve the technical problems, the invention adopts the following technical scheme:
In a first aspect, the present invention provides a display panel comprising:
A substrate;
A plurality of luminous pixels arranged on one side of the substrate, wherein the luminous pixels emit RGB three-color light rays;
The super-surface structure layer is arranged on the light emitting side of the light emitting pixel and is configured to perform phase modulation on 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;
The light-emitting pixel comprises three colors of sub-pixels, the super-surface structure layer comprises a plurality of super-surface units which are arranged at intervals and have three different phases, the three colors of sub-pixels are respectively attached to the super-surface units of three phase structures in a one-to-one correspondence mode, so that the super-surface units corresponding to one phase structure carry out phase modulation on light of one color, and the super-surface units carry out phase modulation on light rays emitted by the sub-pixels, so that the following formulas (1) - (3) are satisfied:
In the case of the formula (1),In order for the phase to be delayed,Delay phase for collimation; For deflecting to different angles;
in the formula (2), f is a focal length, ni is a refractive index of a medium through which light rays incident to different super-surface units pass, in the formula (2) and the formula (3), λ represents a wavelength of the incident light rays, and x/y/z represents a spatial position coordinate of the super-surface structure;
In the formula (3) of the present invention,Representing the angle between the Z axis and the projection of the deflected beam in the XZ plane; representing the angle between the Z-axis and the projection of the deflected beam in the YZ-plane, and no representing the refractive index of the exit medium.
In one embodiment, the display panel includes a microlens array layer stacked on the light emitting surface of the substrate, and the microlens array layer is located between the light emitting pixels and the super-surface structure layer.
In one embodiment, the display panel further comprises a protective glue layer filled between the super surface units, and/or the display panel further comprises packaging glass stacked on one side of the super surface structure layer, which is away from the substrate.
In one embodiment, each of the super surface units is in a columnar geometry or a ring geometry.
In a second aspect, the present invention provides a method for manufacturing a display panel, including the steps of:
Preparing a substrate, and forming a light-emitting pixel on one side of the substrate;
Designing a super-surface structure layer, wherein the super-surface structure layer is designed based on a coupled wave method and a time domain finite difference method, the coupled wave method is used for carrying out unit structure design, and the time domain finite difference method is used for carrying out overall structure design and verification;
Forming the super-surface structure layer on one side of the light-emitting pixel, which is far away from the substrate, wherein the super-surface structure layer is configured to perform phase modulation on a first light beam emitted from the light-emitting pixel to the super-surface structure layer so as to enable a second light beam emitted from the super-surface structure layer to have collimation and directionality;
The light-emitting pixel comprises three colors of sub-pixels, the super-surface structure layer comprises a plurality of super-surface units which are arranged at intervals in an array manner and have three different phases, the sub-pixels with the three colors are respectively attached to the super-surface units with three phase structures in a one-to-one correspondence manner, so that the super-surface units corresponding to one phase structure carry out phase modulation on light with one color, and the super-surface units correspond to the light rays emitted by the sub-pixels and carry out phase modulation, so that the following formulas (1) - (3) are satisfied:
In the case of the formula (1),In order for the phase to be delayed,Delay phase for collimation; For deflecting to different angles;
In the formula (2), f is a focal length, ni is a refractive index of a medium through which light incident to the super-surface structure layer passes, in the formula (2) and the formula (3), λ represents different wavelengths, and x/y/z represents a spatial position coordinate of the super-surface structure;
In the formula (3) of the present invention,Representing the angle between the Z axis and the projection of the deflected beam in the XZ plane; representing the angle between the Z-axis and the projection of the deflected beam in the YZ-plane, and no representing the refractive index of the exit medium.
In one embodiment, designing the subsurface structure layer includes the steps of:
constructing a super-surface structure layer matched with the luminous pixel based on the parameters of the luminous pixel;
discretizing the phase distribution information according to the cycle size of the super surface unit library to obtain a phase discretization result;
The super surface unit structure library corresponds to the light-emitting spectrum range of the light-emitting pixel and comprises a plurality of super surface unit structures, each super surface unit structure corresponds to a phase value in the range of 0 to 2 pi, and the phase values corresponding to the super surface unit structures are different;
And performing super-surface unit array arrangement according to the phase discretization result to construct a super-surface structure layer.
In one embodiment, forming the subsurface structure layer comprises the steps of:
Sequentially depositing a super-surface film layer and a hard mask layer on the light emergent surface of the substrate;
Sequentially performing patterning treatment and etching on the hard mask layer to transfer the patterns 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 super surface structure layer comprises a plurality of super surface units matched with the wavelength of RGB three primary color light.
In a third aspect, the present invention provides an application of a display panel, where the display panel described in any one of the foregoing embodiments or the display panel manufactured by any one of the foregoing method embodiments is applied to naked eye 3D light field display.
In a fourth aspect, the present invention provides an AR near-eye display device comprising:
An optical waveguide having an in-coupling structure and an out-coupling structure;
The display panel according to any one of the foregoing embodiments or the display panel manufactured by any one of the foregoing manufacturing methods, wherein the display panel is used as a light source device and is disposed on one side of the coupling-in structure of the optical waveguide, and light emitted by the display panel enters the optical waveguide through the coupling-in structure and propagates into the coupling-out structure to be coupled out.
In an embodiment, the coupling-in structure comprises a geometric coupling-in device, and the super surface structure layer is arranged at intervals from the geometric coupling-in device or is attached to the mirror surface of the geometric coupling-in device.
As can be seen from the technical scheme, the embodiment of the invention has at least the following advantages and positive effects:
The embodiment of the application 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 super-surface structure layer, wherein the substrate and the super-surface structure layer are sequentially stacked, 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 perform phase modulation on 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 luminous pixel comprises three colors of sub-pixels to emit RGB three-color light, the super-surface structure layer comprises three super-surface units, and the sub-pixels of each color are respectively attached to different super-surface units in a one-to-one correspondence manner, so that each super-surface unit carries out phase modulation on light of one color. On one hand, the super-surface structure layer realizes collimation and directionality of light emitted by the display panel, thereby improving light efficiency and light emitting brightness, reducing light crosstalk, and the display panel can realize naked eye 3D light field display with better effect.
Detailed Description
Exemplary embodiments that embody features and advantages of the present invention will be described in detail in the following description. It will be understood that the invention is capable of various modifications in various embodiments, all without departing from the scope of the invention, and that the description and illustrations herein are intended to be by way of illustration only and not to be construed as limiting the invention.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more of the described features. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
In the description of the present application, unless explicitly stated or limited otherwise, the terms "mounted," "configured," and "connected" are to be construed broadly, and may, for example, be fixedly connected, detachably connected, or integrally connected, mechanically connected, electrically connected, directly connected, indirectly connected via an intervening medium, or communicate between two elements. The specific meaning of the above terms in the present application will be understood in specific cases by those of ordinary skill in the art.
Display pixels typically have a lambertian emission pattern, including standard Light Emitting Diode (LED) dies such as micro light Emitting diodes (MicroLED), and Organic Light Emitting Diodes (OLEDs) and silicon-based OLEDs, etc., and this feature is independent of wavelength. In some display applications, the light emitted from the pixel 200 is required to have collimation and directionality. It should be noted that, the collimation of the light beam means that the light beam is modulated into a parallel light beam by divergent light, and the directionality of the light beam means that the light beam is modulated to emit according to a preset angle. Fig. 1 illustrates that current LED pixels typically have a lambertian emission pattern with a distribution of emission energy that is lambertian, and the emitted light is neither collimated nor directional. Fig. 2 (a) illustrates that the integration of a microlens array over a light emitting pixel increases the collimation of the light emission, the collimation is improved after adding the microlens array, the light emitting angle range is reduced, and the light emitting brightness is improved, but in this way, crosstalk between adjacent pixels exists and the thickness dimension of the display device or the display light machine itself is increased.
Therefore, in order to achieve the collimation and directionality of the light emitted from the LED pixels and to achieve the light and thin requirements of the display device or the display light machine, the present application provides a display panel 10.
Referring to fig. 3 and 4 in combination, the display panel 10 includes a substrate 100, light emitting pixels 200 and a super surface structure layer 300. The number of the light emitting pixels 200 is plural and disposed 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, quantum dots, etc., the super surface structure layer 300 is disposed on the light emitting side of the light emitting pixels 200, and the super surface structure layer 300 is configured to phase modulate the first light beam emitted from the light emitting pixels 200 to the super surface structure layer 300, so that the second light beam emitted from the super surface structure layer 300 has extremely high collimation and directionality (as shown in fig. 3 (a)). The super surface structure layer 300 is formed by arranging super surface unit structure groups with the size smaller than the wavelength of incident light according to a certain arrangement rule, and the super surface structure layer 300 is usually a micro-nano structure (GaN, tiO, siN and the like) constructed on a substrate material (SiO 2, AO3 and the like). The super surface structure layer 300 can realize accurate modulation of the incident light phase by the micro-nano structure optical modulation characteristic thereof, and realize accurate modulation of the incident light phase, thereby realizing accurate regulation and control of the incident light. The light-controllable LED lamp has the characteristics of strong designability, small structural size and accurate light control.
Specifically, in fig. 4, the light-emitting pixel 200 includes three color sub-pixels, namely, a red sub-pixel 201, a green sub-pixel 202 and a blue sub-pixel 203, and the super-surface structure layer 300 is formed by arranging a plurality of super-surface units in an array, and includes three super-surface units with different structures, namely, a red super-surface unit 301, a green super-surface unit 302 and a blue super-surface unit 303. The red light super surface unit 301 is attached to the red light sub-pixel 201 in a one-to-one correspondence mode, the red light super surface unit 301 carries out phase modulation on red light emitted by the red light sub-pixel 201, the green light super surface unit 302 is attached to the green light sub-pixel 202 in a one-to-one correspondence mode, the green light super surface unit 302 carries out phase modulation on green light emitted by the green light sub-pixel 202, the blue light super surface unit 303 is attached to the blue light sub-pixel 203 in a one-to-one correspondence mode, and the blue light super surface unit 303 carries out phase modulation on blue light emitted by the blue light sub-pixel 203. That is, the super surface units of each structure perform phase modulation on light of one color, and each super surface unit performs phase modulation on light emitted by a corresponding sub-pixel, so that the following formulas (1) - (3) are satisfied:
In the case of the formula (1),In order for the phase to be delayed,Delay phase for collimation; For deflecting to different angles;
in the formula (2), f is a focal length, ni is a refractive index of a medium through which light rays incident to different super-surface units pass, in the formula (2) and the formula (3), λ represents a wavelength of the incident light rays, and x/y/z represents a spatial position coordinate of the super-surface structure;
In the formula (3) of the present invention,Representing the angle between the Z axis and the projection of the deflected beam in the XZ plane; representing the angle between the Z-axis and the projection of the deflected beam in the YZ-plane, and no representing the refractive index of the exit medium.
Preferably, referring to fig. 5, in an embodiment, the display panel 10 may further include a microlens structure layer 400, the microlens structure layer 400 is stacked on the light emitting surface of the substrate 100, and the microlens structure layer 400 is located between the light emitting pixels 200 and the super surface structure layer 300. The light emitted by the light-emitting pixel 200 is first modulated and narrowed into a first beam of light by the micro-lens structure layer 400, and then is subjected to a second phase modulation by the super-surface structure layer 300, so that the light (second beam of light) has higher collimation and directivity. It should be understood that, in the present application, whether the microlens structure layer 400 is disposed or not is not limited, without considering that the emitted light has higher collimation and directivity.
Preferably, referring to fig. 4, the super surface structure layer 300, as a micro-nano structure, is extremely vulnerable to damage if directly exposed to air. Therefore, in order to protect the super surface structure layer 300, the display panel 10 further 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 further includes a package glass 600, where the package glass 600 is stacked on a side of the super surface structure layer 300 facing away from the substrate 100, that is, covers the light emitting surface attached to the super surface structure layer 300. It should be understood that the arrangement of the protective adhesive layer 500 or the encapsulation glass 600 is not limited, regardless of whether the super surface structure layer 300 needs to be protected.
Preferably, each of the super surface units has a regular structure such as a columnar geometry or a ring geometry, which facilitates the construction and processing (facilitates array arrangement) of the super surface structure layer 300. It should be understood that the columnar geometry includes, but is not limited to, a cylinder, a cuboid, a cube, and the annular geometry includes, but is not limited to, a concentric cylinder. It should be understood that the shape and morphology of the super surface unit are not limited in the present application, regardless of the convenience of construction and processing of the super surface structure layer 300.
Referring to fig. 6, the present application provides a method for manufacturing a display panel 10, which includes 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 super surface structure layer 300, wherein the design of the super surface structure layer 300 is based on a strict coupled wave method (RCWA) and a time domain finite difference method (FDTD), the RCWA performs unit structure design, and the FDTD performs overall structure design and verification. The main parameters involved in the design process are the height of the super surface structure layer 300 and the morphology of the single super surface unit, which can be regular structures such as columns, rings and the like or free morphology structures;
S30, preparing the display panel 10, forming the super surface structure layer 300 on a side (i.e. the light emitting side) of the light emitting pixel 200 facing away from the substrate 100, where the super surface structure layer 300 is configured to perform phase modulation on 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 extremely high collimation and directionality. The luminous pixel 200 comprises three colors of sub-pixels, the super-surface structure layer 300 comprises a plurality of super-surface units which are arranged at intervals in an array manner and have three different phase structures, the three colors of sub-pixels are respectively attached to the three phases of super-surface units in a one-to-one alignment manner, so that the super-surface units corresponding to one phase structure perform phase modulation on light of one color, and the super-surface units perform phase modulation on light rays emitted by the sub-pixels corresponding to the super-surface units, so that the following formulas (1) - (3) are satisfied:
In the case of the formula (1),In order for the phase to be delayed,Delay phase for collimation; For deflecting to different angles;
in the formula (2), f is a focal length, ni is a refractive index of a medium through which light rays incident to different super-surface units pass, in the formula (2) and the formula (3), λ represents a wavelength of the incident light rays, and x/y/z represents a spatial position coordinate of the super-surface structure;
In the formula (3) of the present invention,Representing the angle between the Z axis and the projection of the deflected beam in the XZ plane; representing the angle between the Z-axis and the projection of the deflected beam in the YZ-plane, and no representing the refractive index of the exit medium.
Referring to fig. 7, in the process of manufacturing the display panel 10, the specific steps for designing the super surface structure layer are as follows:
S21, designing collimation and deflection phases, constructing a super-surface structure layer matched with the luminous pixels based on parameters of the luminous pixels, and extracting phase distribution information of the super-surface structure;
S22, discretizing the phase according to the periodic size of the super surface unit library to obtain a phase discretization result;
s23, constructing a super-surface unit structure library, wherein the super-surface unit structure library corresponds to the light-emitting spectrum range of the light-emitting pixels and comprises a plurality of super-surface unit structures, each super-surface unit structure corresponds to one phase value in the range of 0 to 2 pi, and the phase values corresponding to the super-surface unit structures are different;
s24, constructing a super-surface structure layer, and performing super-surface unit array arrangement according to the phase discretization result to construct the super-surface structure layer.
In one embodiment, discretizing the phase distribution information according to the cycle size of the super surface unit structure library includes dividing the phase distribution information with the cycle of the super surface unit structure as a minimum division scale to make the phase distribution information discrete into phase values within a range of 0-2 pi.
Referring to fig. 8, in the process of manufacturing the display panel 10, the specific steps of forming the super surface structure layer 300 are as follows:
S31, depositing two layers of films, and sequentially depositing a super-surface material film (SiNx, nano-imprinting glue and the like) and a hard mask film (aluminum Al, titanium Ti, chromium Cr and the like) on the material layer of the luminescent pixel 200 (on the light-emitting surface of the substrate 100);
S32, patterning, namely patterning the hard mask film to form a super-surface structure pattern on the hard mask film to form a hard mask layer;
S33, etching, namely etching the super-surface material film by using the hard mask layer as a mask so as to transfer the pattern of the hard mask layer to the super-surface material film;
s34, cleaning and removing the hard mask layer to form a super-surface structure layer;
Wherein the super surface structure layer 300 includes a plurality of super surface unit structures matched to wavelengths of the RGB three primary color light rays.
Preferably, in this embodiment, the super surface unit and the sub-pixels are aligned one by one, and the super surface structure layer and the light-emitting pixels are aligned and bonded by using a high-precision alignment and bonding technology. And simultaneously manufacturing an alignment mark when preparing the light-emitting unit, and referencing the alignment mark when processing the super-surface structure later to realize pixel alignment.
In a third aspect, 3D display is a technique capable of displaying a scene and an object having a sense of depth, so that an observer can directly observe a 3D image having a physical depth. The current 3D display technology mainly comprises naked eye type display and device auxiliary type display, wherein the naked eye 3D display technology is paid attention to because of the advantages of convenience and flexibility of devices such as glasses and the like. The naked eye 3D display technology is a light field display technology. The coded light field information is projected to different positions in the space through the light field modulation device, so that a real 3D light field with continuous parallax at the different positions in the space is formed, and the stereoscopic parallax in a plurality of directions such as horizontal direction, vertical direction and the like can be provided simultaneously. Most of traditional naked eye 3D display devices are based on devices such as a lens array and limited by a lens processing technology and a refraction modulation model, a constraint relationship exists among a 3D visual angle, 3D resolution and display depth, the size is large, crosstalk exists, and the 3D display effect is poor.
Therefore, referring to fig. 9, the display panel 10 or the display panel 10 prepared by the preparation method provided in the previous embodiment is applied to naked eye 3D light field display. The substrate 100 and the light emitting pixels 200 constitute a light source device 12, and the angular spectrum of the intensity of light emitted by the light source device 12 follows a lambertian distribution. The super surface structure layer 300 is used for collimating and beam-oriented emitting the emergent ray of each luminous pixel 200, and the emitting direction is determined by the light field modulation rule displayed by the light field to restore the 3D light field visible to naked eyes. The super surface structure layer 300 is prepared by electron beam exposure and reactive ion etching based on super atoms and a phase template, wherein the light source device 12 and the super surface structure layer 300 are sequentially arranged on the optical path of emergent light. The invention has the advantages of small volume, light weight and low crosstalk, and realizes the naked eye 3D light field display with better effect.
In a fourth aspect, referring to fig. 10 or 11, the present application also provides an AR near-to-eye display device 1, including an optical waveguide 20 and the display panel 10 of the previous embodiment or the display panel 10 prepared by the preparation method. The light waveguide 20 has a coupling-in structure 21 and a coupling-out structure, the display panel 10 is used as a light emitting device and is disposed at one side of the coupling-in structure 21 of the light waveguide 20, and light emitted from the display panel 10 enters the light waveguide 20 through the coupling-in structure 21 to propagate. Wherein the angular spectrum of the intensity of the light emitted by the display panel 10 follows a lambertian distribution. The outgoing light of each pixel is collimated and directionally emitted by the super surface structure layer 300 and then propagates into the optical waveguide 20 to be coupled out of the coupling structure, so that the AR near-eye display device 1 of the present application does not need a lens collimation system and can be coupled with the optical waveguide with higher efficiency. It should be noted that, in the present application, the coupling-out structure is not limited, and only needs to couple out the light in the optical waveguide 20.
Preferably, in the present embodiment, the incoupling structure 21 is a geometrical coupling device, such as geometrical optical elements using mirrors 211 (as shown in fig. 10) and prisms 212 (as shown in fig. 11) for incoupling. Because the super surface structure layer 300 is composed of nano super atoms with sub-wavelength, the volume is extremely small, and the emergent light of the super surface structure layer 300 is collimated and deflected by pixels, so that a traditional lens collimation system is not needed, and the whole system volume of the AR near-eye display device 1 is greatly reduced. In addition, a geometrical coupling device such as the mirror 211 can couple incident light into the optical waveguide without loss, thus solving the problem of low overall light energy utilization. It should be appreciated that when the geometric coupling device is a prism 212, the super surface structure layer 300 may be attached to the mirror surface of the prism 212 or may be spaced apart from the mirror surface of the prism 212. It is to be understood that in other embodiments of the present application, the coupling-in structure 21 may be a coupling structure such as a diffraction grating.
The application provides a display panel 10, a preparation method and application thereof, and an AR near-to-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 disposed on a light emitting side of the light emitting pixel 200, and the super surface structure layer 300 is configured to perform phase modulation on a first light beam emitted from the light emitting pixel 200 to the super surface structure layer 300, so that a second light beam emitted from the super surface structure layer 300 has collimation and directionality. Specifically, the light-emitting pixel 200 includes three color sub-pixels to emit RGB three-color light, and the super surface structure layer 300 includes three kinds of super surface units, and each color sub-pixel is respectively attached to a different super surface unit in a one-to-one correspondence manner, so that each super surface unit performs phase modulation on light of one color. On one hand, the super-surface structure layer 300 realizes collimation and directionality of light emitted by the display panel 10, thereby improving light efficiency and brightness, reducing light crosstalk, and the display panel 10 can realize naked eye 3D light field display with better effect, so that the display panel 10 is applied to naked eye 3D light field display, on the other hand, the super-surface structure layer 300 is formed by arranging super-surface unit structure groups with the dimension smaller than the wavelength of incident light according to a certain arrangement rule, has small thickness dimension and is in a micro-nano level, and is favorable for realizing the light and thin of the display panel 10.
While the invention has been described with reference to several exemplary embodiments, it is to be understood that the terminology used is intended to be in the nature of words of description and of limitation. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.