Pixel unit, display panel and preparation method thereof

Abstract

The invention relates to the technical field of display, and discloses a pixel unit, a display panel and a preparation method thereof, the pixel unit comprises a driving substrate, n pixel layers and a lens, the n pixel layers are sequentially arranged on the driving substrate upwards, the lens is arranged above the uppermost pixel layer, and n is larger than or equal to 2; the pixel layer comprises a luminous body, the luminous body is electrically connected with the driving substrate, and the luminous body is used for emitting light upwards; the light-emitting bodies in each pixel layer are spaced in the horizontal direction and the vertical direction, a plurality of prisms are arranged above the light-emitting bodies in at least n-1 pixel layers, and light emitted by all the light-emitting bodies is converged to a lens and then is emitted in the coaxial direction. According to the technical scheme, the optical axes of the luminous bodies in the pixel units are unified through the structural design, and convergence and shaping collimation of light rays of the pixel units are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a pixel unit, a display panel and a preparation method thereof. BACKGROUND

[0002] Micro-Light Emitting Diode (Micro LED) display technology has attracted widespread attention since its emergence due to its fast response speed, low power consumption, long service life and high luminous efficiency. It is considered to be the next generation display technology after Liquid Crystal Display (LCD), and the full-color display is still a very challenging problem.

[0003] Currently, the structure layout of colorization mainly includes horizontal distribution of RGB light emitters and coaxial vertical arrangement in full-color integration. In the colorization scheme of micro display, blue Micro LED epitaxial wafer combined with color conversion material is commonly used to realize full-color, and there is also a vertical stacking full-color scheme. Due to the fact that high-energy sub-pixels such as blue and green light can easily excite red sub-pixels, resulting in problems such as reduced color purity and narrowed color gamut, the coaxial vertical arrangement scheme is particularly serious. In the horizontal distribution scheme, the pixel cross-sectional shape is often rectangular or right trapezoidal, which is not conducive to light collimation and light extraction. The full-color schemes of vertical and horizontal distribution each have advantages and disadvantages, and there is no good full-color scheme at the moment. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a pixel unit, a display panel and a preparation method thereof. The pixel unit has a horizontally distributed stacked full-color pixel unit structure, which realizes the convergence and shaping of pixel light.

[0005] The present application provides a pixel unit, comprising a driving substrate, n pixel layers arranged in sequence upwards on the driving substrate, and a lens arranged above the uppermost pixel layer, wherein n is greater than or equal to 2. The pixel layer comprises a light emitter, the light emitter is electrically connected to the driving substrate, and the light emitter is used for upward light emission. The light emitters in each pixel layer are spaced apart from each other in both horizontal and vertical directions. The light emitters in at least n-1 pixel layers are provided with a plurality of prisms above them, so that the light emitted by the light emitters in the n pixel layers converges to the lens and is then emitted coaxially upwards through the lens.

[0006] As a further improvement of the above technical solution, the vertical cross-section of the light emitter is an inverted trapezoid.

[0007] As a further improvement of the above technical solution, a spherical mirror is arranged below the light emitter, the light emitter is located in the internal space of the spherical mirror, and the spherical mirror makes the light emitter emit light upward.

[0008] As a further improvement of the above technical solution, the pixel layer comprises a transparent filling layer and a first electron transport layer from bottom to top, the light emitter is located in the transparent filling layer, and the light emitter is electrically connected with the first electron transport layer; the pixel unit further comprises a cathode metal, an anode metal and an insulating layer, the cathode metal is arranged around the pixel layer, the cathode metal is electrically connected with the first electron transport layer, the cathode metal is electrically connected with the driving substrate, the anode metal is electrically connected with the light emitter, the anode metal is electrically connected with the driving substrate, and the insulating layer is arranged around the anode metal, and the insulating layer is used to isolate the anode metal from the spherical mirror and the first electron transport layer respectively.

[0009] As a further improvement of the above technical solution, the light emitter comprises a second electron transport layer, a multi-quantum well layer, a hole transport layer and an ohmic contact layer from top to bottom; the second electron transport layer is electrically connected through the first electron transport layer; and the ohmic contact layer is electrically connected through the anode metal.

[0010] As a further improvement of the above technical solution, the included angle between the prism and the horizontal plane is 20°-80°; and / or, the light emitted by each light emitter is independently selected from one of red light, yellow light, orange light, green light, blue light and purple light; and / or, n is 3.

[0011] As a further improvement of the above technical solution, the pixel unit has a top view shape of one of a circle and a rectangle; and / or, n is 3 and the light emitter has a normal projection on the driving substrate in one of a diagonal line shape, a straight line shape and a “product” shape.

[0012] The application further provides a preparation method of the pixel unit, comprising the following steps: Step one, preparing m pixels, m is equal to n Preparation of a substrate, epitaxial formation of a functional layer on the substrate, and then etching to form the light emitter; Step two, preparation of the pixel unit Preparation of the driving substrate, bonding of the m pixels with the driving substrate after removing the substrate, to obtain a first wafer, wherein at least m-1 pixels are removed from the substrate, and a plurality of prisms are prepared on the light emitting surface of the m-1 pixels; and the lens is prepared above the first wafer to obtain the pixel unit.

[0013] As a further improvement of the above technical solution, a spherical mirror is arranged below the light emitter, the light emitter is located in the internal space of the spherical mirror, and the spherical mirror makes the light emitter emit light upward. The step one includes the following process: The substrate is prepared, the functional layer is formed on the substrate by epitaxy, and then the light emitter is formed by etching. Then, the dielectric layer is formed by deposition, the spherical area is formed on the dielectric layer, the metal film layer is formed by metal deposition, the spherical mirror is formed on the spherical area, and then the metal film layer except the spherical mirror is etched and removed. Then, the transparent filling layer is formed by deposition.

[0014] As a further improvement of the above technical solution, the pixel unit further includes a cathode metal, an anode metal and an insulating layer. The cathode metal is arranged around the pixel layer, the cathode metal is electrically connected with the first electron transport layer and the driving substrate, the anode metal is electrically connected with the light emitter and the driving substrate, and the insulating layer is used to isolate the spherical mirror and the first electron transport layer from the anode metal.

[0015] In the step one, the following process is further included after the transparent filling layer is formed: The first contact hole for accommodating the anode metal and the second contact hole for accommodating the cathode metal are formed on the transparent filling layer. One end of the first contact hole penetrates the spherical mirror and is in contact with the light emitter. The insulating layer is formed on the sidewall surface of the first contact hole. The anode metal is obtained by filling the metal material into the insulating layer. The cathode metal is obtained by filling the metal material into the second contact hole.

[0016] The application further provides a display panel including the pixel unit.

[0017] A pixel unit includes: A pixel unit includes a driving substrate, n pixel layers arranged upward on the driving substrate in sequence, and a lens arranged above the uppermost pixel layer, and n is greater than or equal to 2. The pixel layer includes a light emitter, the light emitter is electrically connected with the driving substrate, and the light emitter is used for emitting light upward. The light emitters in each pixel layer exist with a spacing in both horizontal and vertical directions. A plurality of prisms are arranged above the light emitters in at least n-1 pixel layers, so that the light emitted by the light emitters in n pixel layers converges to the lens, and then is coaxially emitted upward through the lens.

[0018] This technical solution has at least the following beneficial effects: In the pixel unit proposed in this invention, a prism is set above the light emitter in the pixel unit, so that the light emitted by each light emitter in the direction of light emission is refracted by the prism, and the light rays of the light emitter converge at the center above the pixel unit. Then, through the refraction of the lens, the light axis of the light emitter is unified, and a better light emission effect is obtained. This realizes the convergence, shaping and collimation of the light rays of the pixel unit, and overcomes the shortcomings of the existing vertical and horizontal full-color schemes. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of a pixel unit provided in an embodiment of the present disclosure; Figure 2 This is a schematic diagram illustrating the technical effect of a pixel unit provided in an embodiment of the present disclosure; Figure 3 This is a schematic diagram of the structure of a spherical reflector provided in an embodiment of the present disclosure; Figure 4 This is a schematic diagram of the structure of a prism provided in an embodiment of the present disclosure; Figure 5 An orthographic projection of the light-emitting element of a pixel unit on a driving substrate, provided in an embodiment of this disclosure; Figure 6 A schematic diagram illustrating the specific process of a pixel unit fabrication method provided in this embodiment of the disclosure; Figure 7 A schematic diagram illustrating the specific process of a pixel unit fabrication method provided in this embodiment of the disclosure; Figure 8 A schematic diagram illustrating the specific process of a pixel unit fabrication method provided in this embodiment of the disclosure; Figure 9 A schematic diagram illustrating the specific process of a pixel unit fabrication method provided in this embodiment of the disclosure; Figure 10 This is a schematic diagram of a display panel provided in an embodiment of the present disclosure.

[0020] In the attached figures: 1-driving substrate; 2-pixel layer; 21-light emitter; 211-ohmic contact layer; 212-hole transport layer; 213-multiple quantum well layer; 214-second electron transport layer; 22-prism; 23-spherical mirror; 24-first electron transport layer; 25-transparent filling layer; 26-insulating layer; 27-dielectric layer; 28-functional layer; 3-lens; 4-anode metal; 5-cathode metal; 6-substrate. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] The following is combined Figures 1 to 10 Embodiments of the present invention will be described.

[0023] Reference Figure 1 and Figure 2 A pixel unit, comprising: A pixel unit includes a driving substrate 1, and n pixel layers 2 arranged sequentially upward on the driving substrate 1 and a lens 3 arranged above the uppermost pixel layer 2, where n is greater than or equal to 2. The pixel layer 2 includes a light-emitting element 21, which is electrically connected to the driving substrate 1 and is used to emit light upward. Each light-emitting element 21 in the pixel layer 2 has a spacing between each other in both the horizontal and vertical directions. At least n-1 light-emitting elements 21 in the pixel layer 2 are provided with a plurality of prisms 22 above them, so that the light emitted by the light-emitting elements 21 in the n pixel layers 2 converges to the lens 3 and is then emitted upward in the same direction through the lens 3.

[0024] In existing technologies, high-energy light emitters 21 such as blue and green light can easily excite red light emitters 21, leading to problems such as reduced color purity and narrowed color gamut. This problem is particularly severe in coaxial vertical arrangement schemes. Horizontal distribution schemes are not conducive to light collimation and light extraction. (Refer to...) Figure 2 In an embodiment of the present invention, a prism 22 is provided above the light-emitting body 21, so that the light from each light-emitting body 21 facing the light-emitting direction is refracted by the prism 22. The light rays from the light-emitting body 21 converge at the center above the pixel unit, and then are refracted by the lens 3, so that the optical axis of the light-emitting body 21 is unified, thereby obtaining a better light-emitting effect and overcoming the shortcomings of the existing vertical and horizontal full-color schemes.

[0025] Specifically, the driving substrate 1 can be a substrate, such as silicon, silicon carbide, glass, gallium nitride, gallium arsenide, sapphire, etc., or it can be a CMOS substrate or a TFT substrate. The prism 22 can be made of materials such as SiO2, Al2O3, GaN, glass, quartz, resin, zinc selenide (ZnSe), germanium (Ge), calcium fluoride (CaF2), magnesium fluoride (MgF2), etc.

[0026] In some embodiments, the vertical cross-section of the light emitter 21 is an inverted trapezoid. Compared with the light emitter 21 with an inverted trapezoidal vertical cross-section in this embodiment, the light-emitting layer of the light emitter 21 with an inverted trapezoidal vertical cross-section is farther away from the light-emitting surface. The light is trapped in the light emitter 21 more due to reflection at the interface, resulting in lower light extraction efficiency. In the light emitter 21 with an inverted trapezoidal vertical cross-section, the light is closer to the light-emitting surface, experiencing less interface reflection and attenuation. The incident angle and reflection angle on the sidewalls in the light-emitting direction are larger. The light emitted by the light-emitting layer of the light emitter 21 with an inverted trapezoidal vertical cross-section undergoes fewer reflections through the sidewalls, resulting in less refraction loss through the sidewalls, which is beneficial for light collimation and light extraction.

[0027] Reference Figure 2 and Figure 3 In some embodiments, a spherical reflector 23 is provided below the light emitter 21, with the light emitter 21 located within the internal space of the spherical reflector 23. The spherical reflector 23 causes the light emitter 21 to emit light upwards. The spherical reflector 23 encloses the light emitter 21, and its convex surface blocks lateral light crosstalk from the lower light emitter 21. The concave surface of the spherical reflector 23 reflects light rays from the light-emitting layer of the light emitter 21 oriented downwards and to the sides. By providing the spherical reflector 23, the re-collection and extraction of light rays from the sides and downwards of the pixels in this layer are promoted, and the divergent beam is recovered and applied to the light emission direction, thus achieving a beam shaping effect on the light emitter 21.

[0028] Specifically, the reflector is made of a combination of highly reflective metals such as Al and Ag, and their adhesive layers. (See reference...) Figure 3 L is the width of the spherical reflector, H is the height of the spherical reflector, and h0 is the distance between the center of the multi-quantum well layer 213 in the light emitter 21 and the bottom of the reflector. L, H, and h0 can be optimized and adjusted according to the pixel size, where H>h0 and L is greater than the width of the light emitter 21, to ensure that the spherical reflector 23 encloses the light emitter 21.

[0029] Reference Figure 1In some embodiments, the pixel layer 2 includes, from bottom to top, a transparent filling layer 25 and a first electron transport layer 24. The light emitter 21 is located in the transparent filling layer 25 and is electrically connected to the first electron transport layer 24. The pixel unit also includes a cathode metal 5, an anode metal 4, and an insulating layer 26. The cathode metal 5 is disposed around the pixel layer 2 and is electrically connected to the first electron transport layer 24 and the driving substrate 1. The anode metal 4 is electrically connected to the light emitter 21 and the driving substrate 1. The insulating layer 26 is disposed around the anode metal 4 and is used to isolate the anode metal 4 from the spherical reflector 23 and the first electron transport layer 24, respectively. This provides a pixel unit structure scheme that facilitates the fabrication of the pixel unit. Simultaneously, the insulating layer 26 prevents short circuits in the internal structure.

[0030] Specifically, the transparent filler layer 25 is made of dielectric materials such as inorganic or plastic materials. Solid inorganic materials include SiO2, Al2O3, Si3N4, phosphosilicate glass (PSG), or borosilicate glass (BPSG), or any combination thereof. Plastic materials include polymers of SU-8, PermiNex, and benzocyclobutene (BCB), or transparent plastics (resins) including spin-coated glass (SOG), or combinations thereof. It can also be an antireflective film or optical sieve layer composed of inorganic materials, such as a stack of TiO2 and SiO2, or a stack of Ta2O5 and SiO2. The material of the prism 22 is selected and adjusted according to the material of the transparent filler layer 25. Above the transparent filler layer 25 is a first electron transport layer 24, which is an n-type doped compound semiconductor such as GaN or GaAs. The anode metal 4 is a conductive material and can be one or more of the following: opaque Al, Au, Rh, Ag, Cr, Ti, Pt, Sn, Cu, AuSn, TiW, etc. The cathode metal 5 is a conductive material and can be a single or combined film layer of the anode metal 4, the blocking layer, and the ohmic light emitter 21, preferably a combined film layer of ITO, Cu, and their blocking layer. The anode metal 4 and cathode metal 5 are electrically connected to the bonding electrodes of the driving substrate 1. The insulating layer 26 is made of one or more combinations of silicon oxide, aluminum oxide, silicon nitride, SiON, and SiCN.

[0031] Reference Figure 1In some embodiments, the light emitter 21 comprises, from top to bottom, a second electron transport layer 214, a multi-quantum well layer 213, a hole transport layer 212, and an ohmic contact layer 211; the second electron transport layer 214 is electrically connected through the first electron transport layer 24; and the ohmic contact layer 211 is electrically connected through the anode metal 4. The above provides a specific structure and electrical connection scheme for the light emitter 21, which facilitates achieving good light emission effects. Specifically, the second electron transport layer 214 is an n-type doped compound semiconductor such as GaN or GaAs. The multi-quantum wells can radiate any color of light, such as red, blue, green, and yellow, and can be combined with appropriate light emitters 21 according to the desired light color. The hole transport layer 212 is a p-type doped GaN or (Al... x Ga 1-x ) 0.5 In 0.5 P-type doped compound semiconductors, such as P-type doped compounds. The ohmic contact layer 211 can be a metal pad. In addition, the light emitter 21 can also be provided with functional layers 28 such as buffer layers and electron blocking layers.

[0032] In some embodiments, the angle between the prism 22 and the horizontal plane is 20°-80°; and / or, the light emitted by each of the light-emitting elements 21 is independently selected from red, yellow, orange, green, blue, and violet light; and / or, n is 3. The selection of the above structures makes the pixel unit more adaptable and the light emission effect better. Specifically, the angle θ between the prism 22 and the horizontal plane is referenced... Figure 4 The angle of the prism 22 is adjusted according to the refraction requirements of the light emitted by the actual light source 21, and can also be adjusted according to the thickness of the first electron transport layer 24, which is beneficial for beam collimation. Each light source 21 can display any color of light, such as red, orange, green, blue, and purple. The light emission colors of all light sources 21 in the pixel unit can be arbitrarily combined according to actual needs. For example, if the pixel unit has three pixel layers 2, the three light sources 21 can display red, green, and blue light respectively, or they can display blue, green, and red light respectively.

[0033] Reference Figure 5 In some embodiments, the top view shape of the pixel unit is either circular or rectangular; and / or, n is 3 and the orthographic projection of the light-emitting element 21 onto the driving substrate 1 is either diagonal, linear, or triangular. The shape of the pixel unit and the shape of the light-emitting elements 21 can be adjusted according to actual needs to make the display effect of the display panel formed by arranging the pixel units better.

[0034] Reference Figures 6 to 9 Furthermore, this invention also proposes a method for preparing the aforementioned pixel unit, comprising: Step 1: Prepare m pixels, where m is equal to n. Prepare a substrate 6, epitaxially form a functional layer 28 on the substrate 6, and then etch to form the light emitter 21; Step 2: Prepare the pixel unit Prepare the driving substrate 1, remove the substrate 6 from m pixels and bond them sequentially to the driving substrate 1 to obtain a first wafer, wherein at least after removing the substrate 6 from m-1 pixels, a plurality of prisms 22 are prepared on the light-emitting surface of the m-1 pixels; and a lens 3 is prepared above the first wafer to obtain the pixel unit.

[0035] For example in Figures 6 to 8 The figures illustrate one embodiment of the specific process of step one, respectively, showing the preparation of a pixel. The preparation steps in each figure are A, B, C, D, E, F, and G in sequence. Figure 9 The image shows an embodiment of the specific process of step two, with steps A, B, C, D, and E in sequence. Figures 6 to 8 After removing the substrate 6, the three prepared pixels are sequentially bonded to the driving substrate 1, and then a lens 3 is prepared on the obtained first wafer to obtain a pixel unit.

[0036] For the processing of the driving substrate 1, the surface of the driving substrate 1 is chemically and mechanically planarized to achieve a surface roughness of less than 0.8 nm.

[0037] Specifically, for the substrate 6, a functional layer 28 is epitaxially formed on the substrate 6, and then the light emitter 21 is etched to form it, referring to... Figures 6 to 8 In step A to B, epitaxy is performed on substrate 6 using methods such as MOCVD and MBE to epitaxially grow relevant functional layers 28. Then, the functional layers 28 are etched to form the light emitter 21. The etching methods include, but are not limited to, dry etching and wet etching.

[0038] Reference Figure 9 The specific process of step two is as follows: Refer to Figure 9 In step A, the surface of the driving substrate 1 undergoes chemical mechanical planarization to achieve a surface roughness of less than 0.8 nm, and then it is hybrid-bonded with the first layer of pixels. After bonding, the wafer substrate 6 can be removed and thinned by one or more of the following methods: laser lift-off, mechanical thinning, and etching. Then, referring to... Figure 9In step B, a prism 22 is fabricated on the light-emitting surface of the first pixel. The size and number of prisms 22 can be arbitrarily adjusted according to the pixel size. Then, a transparent filler layer 25 is deposited on the wafer surface. Next, contact holes are opened by etching, and atomic layer deposition is used to isolate the contact holes from the first electron transport layer 24. The bottom of the contact holes is then etched open, followed by metallization. Metallization methods include, but are not limited to, PVD, CVD, and ECP, filling the contact holes with metal material. Furthermore, after filling, chemical mechanical polishing can be performed to remove excess metal material, achieving both contact hole isolation and wafer surface planarization. (Refer to...) Figure 9 In steps C and D, a similar method is used to stack the pixels of the second and third layers. (See reference...) Figure 9 After completing the pixel stacking and surface structure fabrication in step E, the lens 3 structure can be further fabricated. The fabrication methods for lens 3 are as follows: Method 1: Coating the wafer surface with resin or plastic materials such as SU-8, exposing according to the pixel areas, then developing to remove the material from non-pixel areas, followed by thermal reflow to form a hemispherical shape from the exposed material. Method 2: Coating the wafer surface with photoresist, exposing according to the pixel areas, then developing to remove the material from non-pixel areas, followed by thermal reflow to form a hemispherical shape from the exposed photoresist, and then transferring the pattern to the transparent filler layer 25 by dry etching. Method 3: Other methods such as nanoimprinting or transfer.

[0039] Reference Figures 6 to 8 In some embodiments, a spherical reflector 23 is provided below the light-emitting body 21, and the light-emitting body 21 is located in the internal space of the spherical reflector 23, which causes the light-emitting body 21 to emit light upward. Step one includes the following process: Prepare the substrate 6, epitaxially form the functional layer 28 on the substrate 6, and then etch to form the light emitter 21; then deposit to form a dielectric layer 27, and form a spherical region on the dielectric layer 27; then perform metal deposition to form a metal film layer, and form a spherical reflector 23 on the spherical region; then etch away the metal film layer except for the spherical reflector 23, and then deposit to form the transparent filler layer 25.

[0040] Specifically, refer to Figures 6 to 8In steps A to B, epitaxy is performed on substrate 6 using methods such as MOCVD and MBE to epitaxially grow relevant functional layers 28. Then, the functional layers 28 are etched to form the light emitter 21. Etching methods include, but are not limited to, dry etching and wet etching. Next, a dielectric layer 27 is deposited. The material can be one or more combinations of silicon oxide, aluminum oxide, silicon nitride, SiON, and SiCN. Deposition methods include, but are not limited to, one or more stacks of PECVD, LPCVD, and ALD. The dielectric layer here can also be the material of the transparent filler layer 25, i.e., it can be deposited by spin coating, static coating, blade coating, inkjet printing, ultrasonic coating, etc. Finally, chemical mechanical planarization or mechanical planarization is performed to thin and planarize the wafer, resulting in a flat wafer surface. (Refer to...) Figures 6 to 8 Steps B to C in the process describe the specific fabrication methods for the spherical region and the spherical mirror 23 as follows: Method 1: Coat the wafer surface with resin or plastic materials such as SU-8, expose according to the pixel areas, then develop to remove the material from the non-pixel areas, and then reflow the exposed material to form a spherical region. Method 2: Coat the wafer surface with photoresist, expose according to the pixel areas, then develop to remove the material from the non-pixel areas, and then reflow the exposed photoresist to form a spherical region. Then, transfer the pattern to the dielectric layer 27 by dry etching. Method 3: Other methods such as nanoimprinting or transfer. After the spherical region is fabricated, metal is deposited on the entire wafer surface by sputtering. Then, the surface metal in some areas is etched clean by dry etching or wet etching, leaving only the metal film layer of the spherical region. A transparent filler layer 25 is deposited on the surface, or a transparent dielectric layer 27 can be deposited. The deposition method of the transparent filler layer 25 can refer to the aforementioned deposition method of the transparent dielectric layer 27. Then, a flat wafer surface is achieved by chemical mechanical planarization or pure mechanical planarization.

[0041] Reference Figures 6 to 8 In some embodiments, the pixel unit further includes a cathode metal 5, an anode metal 4, and an insulating layer 26. The cathode metal 5 is disposed around the pixel layer 2 and is electrically connected to the first electron transport layer 24 and the driving substrate 1. The anode metal 4 is electrically connected to the light emitter 21 and the driving substrate 1. The insulating layer 26 is used to isolate the spherical reflector 23 and the first electron transport layer 24 from the anode metal 4.

[0042] In step one, after forming the transparent filler layer 25, the following process is also included: A first contact hole for accommodating the anode metal 4 and a second contact hole for accommodating the cathode metal 5 are formed on the transparent filling layer 25. One end of the first contact hole penetrates the spherical reflector 23 and contacts the light emitter 21. An insulating layer 26 is deposited on the sidewall surface of the first contact hole. Metal material is filled into the insulating layer 26 to obtain the anode metal 4, and metal material is filled into the second contact hole to obtain the cathode metal 5.

[0043] Specifically, refer to Figures 6 to 8 Steps D, E, F, and G in the diagram involve first opening the contact hole using photolithography, then depositing an insulating layer 26 on the sidewalls of the contact hole using atomic layer deposition to achieve isolation, followed by etching to open the bottom of the contact hole again. The contact hole shown in the diagram is etched using either dry or wet etching methods. Metallization methods include, but are not limited to, PVD, CVD, and ECP, filling the contact hole with metal material. Furthermore, after filling, chemical mechanical polishing can be performed to remove excess metal material, achieving both contact hole isolation and wafer surface planarization.

[0044] Reference Figure 10 The present invention also proposes a display panel including the pixel unit proposed in this invention. The display panel including the pixel unit proposed in this invention has a better display effect compared with the prior art.

[0045] The preferred embodiments of the present invention have been described in detail above, but the present disclosure is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of the present disclosure.

[0046] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0047] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

Claims

1. A pixel unit, characterized in that, It includes a driving substrate (1), and n pixel layers (2) sequentially arranged upward on the driving substrate (1) and a lens (3) arranged above the uppermost pixel layer (2), where n is greater than or equal to 2; The pixel layer (2) includes a light-emitting body (21), the light-emitting body (21) is electrically connected to the driving substrate (1), and the light-emitting body (21) is used for emitting light upward; the light-emitting bodies (21) in each pixel layer (2) have a spacing between each other both in the horizontal direction and in the vertical direction, and a plurality of prisms (22) are arranged above the light-emitting bodies (21) in at least n - 1 pixel layers (2), so that the light emitted by the light-emitting bodies (21) in the n pixel layers (2) converges to the lens (3), and then is emitted upward coaxially through the lens (3).

2. The pixel unit according to claim 1, characterized in that, The vertical cross-section of the light-emitting body (21) is an inverted trapezoid.

3. The pixel unit according to claim 1, characterized in that, A spherical mirror (23) is provided below the light-emitting body (21), the light-emitting body (21) is located in the inner space of the spherical mirror (23), and the spherical mirror (23) makes the light-emitting body (21) emit light upward.

4. The pixel unit according to claim 3, characterized in that, The pixel layer (2) sequentially includes a transparent filling layer (25) and a first electron transport layer (24) from bottom to top, the light-emitting body (21) is located in the transparent filling layer (25), and the light-emitting body (21) is electrically connected to the first electron transport layer (24); the pixel unit further includes a cathode metal (5), an anode metal (4) and an insulating layer (26), the cathode metal (5) is arranged around the pixel layer (2), the cathode metal (5) is electrically connected to the first electron transport layer (24), the cathode metal (5) is electrically connected to the driving substrate (1), the anode metal (4) is electrically connected to the light-emitting body (21), the anode metal (4) is electrically connected to the driving substrate (1), and the insulating layer (26) is arranged around the anode metal (4), and the insulating layer (26) is used to isolate the anode metal (4) from the spherical mirror (23) and the first electron transport layer (24) respectively.

5. The pixel unit according to claim 4, characterized in that, The light-emitting body (21) sequentially includes a second electron transport layer (214), a multi-quantum well layer (213), a hole transport layer (212) and an ohmic contact layer (211) from top to bottom; the second electron transport layer (214) is electrically connected through the first electron transport layer (24); the ohmic contact layer (211) is electrically connected through the anode metal (4).

6. The pixel unit according to claim 1, characterized in that, The included angle between the prism (22) and the horizontal plane is 20° - 80°; and / or, the light emitted by each light-emitting body (21) independently selects one of red light, yellow light, orange light, green light, blue light and purple light; and / or, n is 3.

7. The pixel unit according to claim 1, characterized in that, The top view shape of the pixel unit is one of a circle and a rectangle; and / or, n is 3 and the orthographic projection of the light-emitting body (21) on the driving substrate (1) is one of a diagonal shape, a straight shape and a "pin" shape 8. A method for fabricating a pixel unit according to any one of claims 1 to 7, characterized in that, It includes the following steps: Step 1, prepare m pixels, where m is equal to n Prepare a substrate (6), epitaxially form a functional layer (28) on the substrate (6), and then etch to form the light emitter (21). Step 2: Prepare the pixel unit Prepare the driving substrate (1), remove the substrate (6) from m pixels and bond them sequentially to the driving substrate (1) to obtain a first wafer, wherein at least after removing the substrate (6) from m-1 pixels, a plurality of prisms (22) are prepared on the light-emitting surface of the m-1 pixels; and a lens (3) is prepared above the first wafer to obtain the pixel unit.

9. The method for preparing a pixel unit according to claim 8, characterized in that, A spherical reflector (23) is provided below the light-emitting body (21), and the light-emitting body (21) is located in the internal space of the spherical reflector (23). The spherical reflector (23) causes the light-emitting body (21) to emit light upward. Step one includes the following process: Prepare the substrate (6), epitaxially form the functional layer (28) on the substrate (6), and then etch to form the light emitter (21); then deposit to form a dielectric layer (27), and form a spherical region on the dielectric layer (27); then perform metal deposition to form a metal film layer, and form a spherical reflector (23) on the spherical region, then etch away the metal film layer except for the spherical reflector (23), and then deposit to form the transparent filler layer (25).

10. The method for preparing a pixel unit according to claim 9, characterized in that, The pixel unit further includes a cathode metal (5), an anode metal (4), and an insulating layer (26). The cathode metal (5) is disposed around the pixel layer (2). The cathode metal (5) is electrically connected to the first electron transport layer (24) and the driving substrate (1). The anode metal (4) is electrically connected to the light emitter (21) and the driving substrate (1). The insulating layer (26) is used to isolate the spherical reflector (23) and the first electron transport layer (24) from the anode metal (4). In step one, after forming the transparent filler layer (25)... Includes the following processes: A first contact hole for accommodating the anode metal (4) and a second contact hole for accommodating the cathode metal (5) are formed on the transparent filling layer (25). One end of the first contact hole penetrates the spherical reflector (23) and contacts the light emitter (21). An insulating layer (26) is deposited on the sidewall surface of the first contact hole. The anode metal (4) is obtained by filling the insulating layer (26) with metal material, and the cathode metal (5) is obtained by filling the second contact hole with metal material.

11. A display panel, characterized in that, Includes the pixel unit as described in any one of claims 1 to 7.

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