An ultra-high resolution nano-light source device and its application

Abstract

The present invention discloses a preparation method of an ultra-high resolution nano light source device, which includes: the first step, preparing a bottom conductive nanowire array channel on an insulating substrate by a nanowire transfer technique or by adopting photolithography, etching and direct growth techniques of nanowires, and depositing a bottom metal electrode at one end of the channel; the second step, preparing a functional light-emitting material thin film as a nano-LED light source by a spin coating method; the third step, covering the functional light-emitting material with a top conductive nanowire array intersecting with the bottom conductive nanowire array by a transfer method, and defining a top metal electrode region; the fourth step, performing wire bonding and encapsulation protection on the prepared light-emitting device to improve stability. The present invention proposes a brand-new novel nano light source display technology with high-density integration, which can achieve an ultra-high spatial resolution of 25,400 PPI and can be applied to the field of large-area high-definition virtual reality (VR) technology.

Description

Technical Field

[0001] The present invention relates to the field of nano light source display technology, and in particular to an ultra-high resolution nano light source device and advanced virtual reality display applications. Background Art

[0002] In the field of high-definition display, the area and spacing of the LED light-emitting unit determine the resolution and high definition of the display screen. In recent years, mobile phones and electronic devices have been miniaturized. The buttons, seven-segment displays, and small dot-matrix displays of mobile phones mostly use industry-standard 1608 (0603) specifications (1.6mm x 0.8mm) small SMD LEDs. The minimum spacing of LED lamp beads that can be achieved on the market is 0.7mm. The bottleneck lies in the packaging technology of the lamp beads and their expensive maintenance costs. Therefore, the development of a new type of integrated and positionable nano-light source display technology is expected to overcome the problem that the size of LEDs cannot be significantly reduced and high-density integration cannot be achieved.

[0003] Functional luminescent materials can be selected from quantum dot materials or perovskite materials with high photoluminescence quantum efficiency and high color purity (SJPark, et al, Adv. Mater. Technol. 2022, 2201070). Among them, quantum dot materials have a unique quantum confinement effect and can emit a spectrum of specific wavelengths. They are ideal luminescent materials (SC Sullivan, Nature Photonics 2009, 3, 315-316), and can be prepared and integrated on a large area by a simple spin coating method. At present, the quantum dot luminescent materials in display technology mainly include: CdSe, CdS (K. Cho, et al. Nature Photon. 2009, 3, 341–345) and silicon-based quantum dots (SY Zhao, et al J. Semicond. 2018, 39, 061008), etc., which can be applied to new display technologies, especially the next generation of display platforms for deeper interaction between people and digital devices - virtual reality (VR), making color display more realistic and accurate.

[0004] The image resolution required for modern VR is at least >1000PPI (pixels per inch). Currently, consumer VR headsets on the market can reach up to around 1200 pixels per inch (PPI). Relevant researchers have developed ultra-high-resolution 4K VR liquid crystal displays (LCDs) with more than 2000PPI.

[0005] However, the inventors of the present application have found that there are still many problems in the current technology. Problems such as uneven patterns and high-density integration of functional luminescent materials limit the process of ultra-high-resolution patterns. In addition, traditional LCDs may experience aging phenomena after long-term use. Therefore, there is an urgent need to develop new display technologies with excellent stability, low power consumption, and ultra-high resolution, and to expand them into multiple directions such as 3D display, flexible display, and transparent display. Summary of the Invention

[0006] In view of the problems of low resolution and poor integration in the existing display technologies, the present invention provides a nano-light source device with ultra-high resolution and high integration, which is applied to the VR field to make the color display more realistic.

[0007] The present application provides a method for preparing an ultra-high-resolution nano-light source device, which is characterized by including the following steps:

[0008] First step: Prepare a bottom conductive nanowire array channel on an insulating substrate through a nanowire transfer technology or by using photolithography, etching, and direct growth technology of nanowires. Then, deposit a bottom metal electrode at one end of the channel through photolithography and deposition processes.

[0009] Second step: Prepare a functional luminescent material thin film by spin coating as a nano-LED light source.

[0010] Third step: Cover the functional luminescent material with a top conductive nanowire array that intersects with the bottom conductive nanowire array through a transfer method, and define the top metal electrode area. The bottom metal electrode and the top metal electrode are electrically connected to form a current loop for electrical testing, that is, nano-scale area light emission is achieved at the intersection point.

[0011] Fourth step: Perform wire bonding and encapsulation protection on the prepared light-emitting device to improve stability.

[0012] Specifically, the preparation method mentioned in the present invention includes the following steps:

[0013] a1. Transfer a bottom conductive close-packed silicon-nickel alloy nanowire array or a heavily doped silicon nanowire array to the surface of a wafer / glass / flexible substrate.

[0014] a2. Selectively deposit a bottom metal electrode in a specific area through photolithography and electron beam evaporation processes. The bottom metal electrode is in contact with the bottom conductive nanowires.

[0015] a3. Spin coat a functional luminescent material thin film on the surface of the bottom conductive nanowires by using a spin coating process.

[0016] a4. Transfer the top-layer close-packed conductive alloy nanowire array or heavily doped silicon nanowire array to the luminescent material thin film by a transfer method, and make it cross with the arrangement direction of the bottom-layer conductive nanowires;

[0017] a5. Selectively deposit the top-layer metal electrode in a specific area by photolithography and electron beam evaporation processes, and the top-layer metal electrode is in contact with the top-layer conductive nanowires;

[0018] a6. Design and apply a voltage through an external circuit to emit light at the intersection of the two-layer nanowire arrays;

[0019] a7. Perform wire bonding and encapsulation protection on the fabricated light-emitting device.

[0020] Specifically, the preparation method mentioned in the present invention includes the following steps:

[0021] b1. Define guiding steps on the substrate by photolithography technology, then perform channel etching by inductively coupled plasma, and continue with photolithography and then deposit catalytic metal on one side of the guiding steps;

[0022] b2. Put the above sample into a plasma-enhanced chemical vapor deposition (PECVD) system, and directly grow the bottom-layer heavily doped silicon nanowire array by using the planar solid-liquid-solid growth mechanism;

[0023] b3. Selectively deposit the bottom-layer metal electrode in a specific area by photolithography and electron beam evaporation (EBE) processes, and the bottom-layer metal electrode is in contact with the bottom-layer heavily doped silicon nanowires;

[0024] b4. Spin-coat a functional luminescent material thin film on the surface of the bottom-layer heavily doped silicon nanowires by spin-coating technology;

[0025] b5. Grow top-layer heavily doped conductive nanowires with the same parameters on another substrate and then cross-transfer them to the functional luminescent material thin film;

[0026] b6. Selectively deposit the top-layer metal electrode in a specific area by photolithography and electron beam evaporation (EBE) processes, and the top-layer metal electrode is in contact with the top-layer heavily doped conductive nanowires;

[0027] b7. Design and apply an appropriate voltage through an external circuit to emit light at the intersection of the two-layer nanowire arrays;

[0028] b8. Perform wire bonding and encapsulation protection on the fabricated light-emitting device.

[0029] Preferably, the bottom-layer conductive nanowires and the top-layer conductive nanowires are alloy nanowires obtained by alloying semiconductor nanowires, metal nanowires or organic nanowires, and the metal material used for the alloying treatment is Ni or Pt.

[0030] The present invention also discloses a nano light source device, including a substrate material, characterized in that: it further includes a bottom metal electrode, a bottom conductive nanowire array, a functional light-emitting material thin film, a top conductive nanowire array, and a top metal electrode; the bottom conductive nanowire array is disposed on the substrate material, the functional light-emitting material thin film is spin-coated on the bottom conductive nanowire array, the top conductive nanowire array covers the functional light-emitting material thin film and intersects with the arrangement direction of the bottom conductive nanowire array; the bottom metal electrode is in contact with the bottom conductive nanowire array, the top metal electrode is in contact with the top conductive nanowire array, and the bottom metal electrode is electrically connected to the top metal electrode.

[0031] Preferably, the functional light-emitting material is an electroluminescent thin film material prepared by a solution method and spin-coated on the bottom conductive nanowire array.

[0032] Preferably, the top metal electrode and the bottom metal electrode are Ag, Al, a Cr-Au stack, a Pt-Au stack, NiAu, or TiAu.

[0033] Preferably, the substrate material is a silicon substrate, a quartz wafer, a SiN x -SiO2 stack, a flexible stack substrate, a polydimethylsiloxane PDMS, or a polyimide PI substrate.

[0034] Preferably, it further includes a top encapsulation layer, and the top encapsulation layer is a transparent material.

[0035] Preferably, the nano light source device described in the present application can be used for VR display, 3D display, flexible display, or transparent display.

[0036] One or more technical solutions provided by the present application have at least the following technical effects or advantages:

[0037] 1. Based on the existing light source display technology, the present invention combines highly conductive nanowire materials and functional light-emitting materials, and proposes a new preparation method for a new nano light source display technology with high-density integration, which can achieve an ultra-high spatial resolution of 25400 PPI and can be applied to the field of large-area high-definition virtual reality (VR) technology.

[0038] 2. The present invention uses the highly conductive nanowires with a high density and a nano length (about 200 μm) prepared as the bottom conductive channel, defines and deposits metal through a simple lithography technique, then spin-coats a light-emitting material simply and transfers the conductive nanowires with the same high density and a nano length (about 200 μm) crosswise, and then defines the electrodes again, so that light can be emitted at the intersection of the two layers of nanowires, achieving ultra-high resolution.

[0039] 3. Compared with the thin film materials used in traditional light source display technologies, the channel materials used in the present invention can give full play to the advantages of high density and integrable positioning of nanowire materials, and the morphology of the nanowires can be designed to be suitable for the flexible display electronics field. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the structure of the nano light source device in Embodiment 1 of the present invention;

[0041] Figure 2 is Figure 1 exploded view of the structure of the nano optical component in;

[0042] Figure 3 Flow chart of the preparation of the high-resolution nano light source display technology for the directly grown bottom heavily doped silicon nanowires and the transferred top nanowires in Embodiment 1 of the present invention;

[0043] Figure 4 Schematic diagram for calculating the resolution with the lengths of the two layers of heavily doped nanowires both being 200 μm as an example in Embodiment 1 of the present invention;

[0044] Figure 5 Flow chart of the preparation of the high-resolution nano light source display technology with both layers of nanowires prepared from transferred highly conductive nanowires in Embodiment 2 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0046] Embodiment 1

[0047] This embodiment provides an ultra-high resolution nano light source device, the structure of which is as Figures 1 - 2 shown, including a substrate material 1, a bottom conductive nanowire array 2, a bottom metal electrode 3, a functional light-emitting material thin film 4, a top conductive nanowire array 5, and a top metal electrode 6; wherein:

[0048] The bottom conductive nanowire array 2 is placed on the substrate material 1, the functional light-emitting material thin film 4 is spin-coated on the bottom conductive nanowire array 2, the top conductive nanowire array 5 covers the functional light-emitting material thin film 4 and intersects with the arrangement direction of the bottom conductive nanowire array 2; the bottom metal electrode 3 is in contact with the bottom conductive nanowire array 2, the top metal electrode 6 is in contact with the top conductive nanowire array 5, and the bottom metal electrode 6 is electrically connected to the top metal electrode 3.

[0049] The highly conductive nanowire structure in this embodiment can be heavily doped highly conductive silicon nanowires directly grown by the IPSLS growth mechanism, or silicon carbide semiconductor nanowires, metal nanowires such as silver, copper, alloy nanowires, or organic nanowires such as fibers.

[0050] Preferably, the functional luminescent material is an electroluminescent thin film material prepared by a solution method and spin-coated on the underlying conductive nanowire array. Such as organic materials, perovskites, quantum dots, etc.

[0051] Preferably, the top metal electrode and the bottom metal electrode can be Ag, Al, Cr-Au stack, Pt-Au stack, NiAu or TiAu, etc., and the deposition techniques include sputtering, evaporation, screen printing, etc.

[0052] Preferably, the substrate refers to a material that can be etched by different etching methods, including silicon substrates, quartz wafers, SiN x -SiO2 stack, flexible stack substrate, polydimethylsiloxane PDMS, polyimide PI substrate, etc.

[0053] Preferably, it further includes a top encapsulation layer, and the top encapsulation layer is a transparent material. The top encapsulation layer is a transparent material, such as PMMA, FEP, EVA, etc., which can not only protect the entire device but also transmit light.

[0054] Preferably, the nanolight source device described in this application can be used for VR display, 3D display, flexible display or transparent display.

[0055] This embodiment also provides a preparation method for the above-mentioned ultra-high resolution nanolight source device, as Figure 3 shown, specifically including the following steps:

[0056] b1. Use photolithography technology to define guiding steps on the substrate, then perform channel etching by inductively coupled plasma, and then continue with photolithography and then evaporate a catalytic metal indium strip on one side of the guiding steps.

[0057] b2. Place the above-mentioned sample into a plasma chemical enhanced vapor deposition (PECVD) system and directly grow the bottom heavily doped silicon nanowires by using the in-plane solid-liquid-solid (IPSLS) growth mechanism. Specifically, first, pattern the substrate material to leave an etching area, and use wet etching / dry etching processes to process the etching area to obtain a channel with a specific morphology. Selectively position and deposit metallic indium in the vertical area of the etched channel area, and introduce a reducing gas H2 to process the catalytic metallic indium strip into catalytic metal balls. Then introduce solid doping precursors such as introducing silane and phosphine or borane in appropriate proportions, etc. After that, perform sample annealing treatment, and then high-conductivity heavily doped nanowires can be grown with diameter positioning. Subsequently, continue to introduce H2 to remove the residual precursors.

[0058] More specifically, after growing undoped nanowires by IPSLS for the bottom high-conductivity nanowire material in this embodiment, alloying treatment can be performed on the nanowires. The metal materials used for alloying treatment include easily diffusible metals such as Ni and Pt. Alloying treatment can significantly improve the conductivity of the nanowires. For these alloy nanowires, they can also be transferred to the required substrate, and the electrode areas can be defined by photolithography and metal electrodes can be deposited.

[0059] More specifically, the patterning treatment in this embodiment includes rectangles, circles, rhombuses, wavy shapes, and all regular and irregular figures.

[0060] More specifically, the catalytic metal for inducing nanoparticles in this embodiment can also be Sn, Bi, Ga, Fe, Au, etc. and their alloy materials.

[0061] More specifically, the precursor gaseous source in this embodiment can also be other dopable gaseous sources.

[0062] More specifically, the doping element in the doping precursor in this embodiment can be phosphorus or boron.

[0063] b3. Then, selectively deposit the bottom metal electrode in the specific area by photolithography and electron beam evaporation (EBE) processes, with a thickness of 50 nm. This electrode has good contact with the bottom conductive nanowires.

[0064] b4. Spin-coat a functional luminescent material such as a quantum dot solution on its surface by using the spin-coating process.

[0065] b5. After growing top-layer heavily doped nanowires with the same parameters on another substrate, cross-transfer them onto the luminescent material.

[0066] b6. Selectively deposit the top metal electrode in the specific area by photolithography and electron beam evaporation (EBE) processes, with a thickness of 50 nm. This electrode has good contact with the top conductive nanowires.

[0067] b7. By designing and applying an appropriate voltage through an external circuit, light can be emitted at the intersection of the two layers of nanowires.

[0068] b8. Lead wires are welded to and the fabricated light-emitting device is encapsulated and protected.

[0069] In this embodiment, taking the length of the bottom-layer grown nanowires as 200 μm as an example, the top-layer highly conductive nanowires are grown on the required substrate. After a length of 200 μm, they are transferred onto the functional light-emitting material, such as Figure 4 As shown, through calculation, the resolution of a super-high-resolution nano-light source display technology prepared by the present invention can be as high as 25400, and it can be applied to the advanced VR field. According to the resolution calculation formula as follows,

[0070] Resolution (PPI):

[0071] 1 inch = 25400 μm

[0072] X: Number of length pixels; Y: Number of width pixels; Z: Diagonal length

[0073] In this embodiment, the structure of the functional light-emitting material forms a light-emitting source at the intersection of the two layers of nanowires, and the size of the light source can be reduced to the nanometer level. The present invention can realize the structure of a nano-scale light-emitting diode (LED) with super-high spatial resolution by using a simple lithography technique. The PPI can exceed 20000, and it can be applied to the fields of large-area high-definition display and advanced virtual reality (VR) technology.

[0074] Example 2

[0075] This embodiment provides a preparation method for a super-high-resolution nano-light source device, as Figure 5 shown, including the following steps:

[0076] a1. Transfer the bottom-layer close-packed silicon-nickel alloy nanowires / heavily doped silicon nanowires with high conductivity to the surface of a wafer / glass / flexible substrate;

[0077] a2. Selectively deposit a bottom-layer metal electrode with a thickness of 50 nm in a specific area through lithography and electron beam evaporation (EBE) processes. This electrode has good contact with the bottom-layer conductive nanowires;

[0078] a3. Spin-coat a functional light-emitting material such as a quantum dot solution on its surface using a spin-coating process;

[0079] a4. Cross-transfer the top-layer highly conductive alloy nanowires or heavily doped silicon nanowires onto the light-emitting material through a transfer method;

[0080] a5. Selectively deposit the top metal electrode with a thickness of 50 nm in the characteristic area through photolithography and electron beam evaporation (EBE) processes; the electrode has good contact with the top conductive nanowires.

[0081] a6. Light can be emitted at the intersection of the two layers of nanowires by designing and applying an appropriate voltage through an external circuit.

[0082] a7. Perform wire bonding and encapsulation protection on the fabricated light-emitting device.

[0083] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing an ultra-high resolution nano light source device, characterized in that: The following steps are involved: The first step is to prepare a bottom conductive nanowire array channel on an insulating substrate by nanowire transfer technology or by photolithography, etching and nanowire direct growth technology, and then deposit a bottom metal electrode at one end of the channel by photolithography and deposition process; The second step is to prepare a functional luminescent material film as a nano-LED light source by spin coating; The third step is to cover the functional luminescent material with a top conductive nanowire array that intersects with the bottom conductive nanowire array by a transfer method, and define a top metal electrode region, wherein the bottom metal electrode and the top metal electrode are electrically connected to form a current loop, and an electrical test is performed to achieve nanoscale regional luminescence at the intersection; The fourth step is to perform lead welding and packaging protection on the prepared light-emitting device to improve stability.

2. The method for preparing an ultra-high resolution nano light source device according to claim 1, characterized in that: The following steps are involved: a1. Transferring the underlying conductive densely packed silicon-nickel alloy nanowire array or heavily doped silicon nanowire array to the surface of a wafer / glass / flexible substrate; a2. selectively depositing a bottom metal electrode in a specific area by photolithography and electron beam evaporation process, wherein the bottom metal electrode contacts the bottom conductive nanowire; a3. Spin-coating a functional light-emitting material film on the surface of the bottom conductive nanowires using a spin-coating process; a4. Transferring the top densely packed conductive alloy nanowire array or heavily doped silicon nanowire array to the light emitting material film by a transfer method, and crossing the arrangement direction of the bottom conductive nanowires; a5. selectively depositing a top metal electrode in a specific area by photolithography and electron beam evaporation, wherein the top metal electrode contacts the top conductive nanowire; a6. Light is emitted at the intersection of two layers of nanowire arrays by designing an external circuit and applying voltage; a7. Perform wire welding and packaging protection on the prepared light-emitting device.

3. The method for preparing an ultra-high resolution nano light source device according to claim 1, characterized in that: The following steps are involved: b1. Use photolithography to define a guide step on the substrate, then use inductively coupled plasma to perform channel etching, continue photolithography, and then perform catalytic metal evaporation on one side of the guide step; b2. Place the sample processed in step b1 into a plasma chemically enhanced vapor deposition (PECVD) system, and directly grow a bottom layer of heavily doped silicon nanowire arrays using a planar solid-liquid-solid growth mechanism; b3, selectively depositing a bottom metal electrode in a characteristic area by photolithography and electron beam evaporation (EBE) process, wherein the bottom metal electrode is in contact with the bottom heavily doped silicon nanowire; b4, using a spin coating process to spin-coat a functional light-emitting material film on the surface of the bottom heavily doped silicon nanowires; b5, growing a top layer of heavily doped conductive nanowires with the same parameters on another substrate and then cross-transferring them to the functional light-emitting material film; b6. selectively depositing a top metal electrode in a characteristic area by photolithography and electron beam evaporation (EBE) process, wherein the top metal electrode contacts the top heavily doped conductive nanowire; b7. Light is emitted at the intersection of two layers of nanowire arrays by designing an external circuit and applying a suitable voltage; b8. Perform wire welding and packaging protection on the prepared light-emitting device.

4. A nano light source device, comprising a substrate material, characterized in that: It also includes a bottom metal electrode, a bottom conductive nanowire array, a functional light-emitting material film, a top conductive nanowire array, and a top metal electrode; The bottom conductive nanowire array is placed on the substrate material, the functional luminescent material film is spin-coated on the bottom conductive nanowire array, and the top conductive nanowire array covers the functional luminescent material film and crosses the arrangement direction of the bottom conductive nanowire array; The bottom metal electrode contacts the bottom conductive nanowire array, the top metal electrode contacts the top conductive nanowire array, and the bottom metal electrode is electrically connected to the top metal electrode.

5. The nano light source device according to claim 4, characterized in that: The functional luminescent material is an electroluminescent thin film material prepared by a solution method and spin-coated on the bottom conductive nanowire array.

6. The nano light source device according to claim 4, characterized in that: The top metal electrode and the bottom metal electrode are Ag, Al, Cr-Au stack, Pt-Au stack, NiAu or TiAu.

7. The nano light source device according to claim 4, characterized in that: The substrate material is a silicon substrate, a quartz sheet, SiN x -SiO2 laminate, flexible laminate substrate, polydimethylsiloxane PDMS or polyimide PI substrate.

8. The nano light source device according to claim 4, characterized in that: It also includes a top encapsulation layer, which is made of transparent material.

9. Use of the nano light source device according to any one of claims 4 to 8, characterized in that: Used for VR display, 3D display, flexible display or transparent display.

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