Micro-LED Display Fabrication Without RGB Mass Transfer
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Solution Overview
Problem
Existing micro display technologies face challenges in transferring micro-light-emitting chips of primary colors RGB due to reduced pixel sizes, leading to yield rate issues and difficulties in achieving efficient green light conversion for full-color displays.
Innovation Solution
A display device and fabrication method that eliminates the need for mass transfer by using a control panel with multiple conductive layers of different thicknesses, where micro-light-emitting elements with different colors are independently formed and bonded without overlapping projections, allowing for free allocation of light-emitting areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If quantum dot materials are used for green light conversion, then full-color display is achieved, but conversion efficiency is reduced and lifespan is affected
Solution Approach 1:
The invention segments the color display function into multiple independent micro light-emitting elements, each emitting a primary color (red, green, blue). Instead of using quantum dot materials for color conversion, the patent directly bonds separate micro light-emitting elements with different emission colors onto the control panel, eliminating the need for quantum dot layers and their associated efficiency and lifespan issues.
2Adaptability or versatility
If mass transfer process is used for micro-light-emitting chips, then full-color display is achieved, but yield rate is reduced due to reduced pixel sizes
Solution Approach 1:
The invention merges the fabrication process of multiple micro light-emitting elements with different colors into a single integrated process. All micro light-emitting elements (red, green, blue) are fabricated on their respective substrates and then bonded together in one step onto the control panel, eliminating the need for separate mass transfer processes for each color and significantly improving yield rate.
Solution Approach 2:
The patent transitions from a planar mass transfer approach to a three-dimensional stacking approach. Micro light-emitting elements are arranged in vertical layers above the control panel, with each element type (RGB) positioned at different heights. This dimensional change allows for simplified bonding and eliminates the complexity of precise lateral alignment required in traditional mass transfer processes.
3Area of moving object
If micro-light-emitting elements with different colors are placed closer together, then pixel size is reduced, but transfer difficulty increases
Solution Approach 1:
The patent resolves the transfer difficulty by moving micro light-emitting elements to different vertical layers rather than arranging them in a single plane. Elements are positioned at different heights above the control panel, with spacing in the vertical dimension compensating for reduced horizontal spacing. This allows for smaller pixel sizes while maintaining ease of manufacture through simplified bonding processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly improves the yield rate of display device fabrication, reduces transfer and repair costs, and enhances light-emitting efficiency and lifespan without relying on quantum dot color conversion technology.
Implementation Method 1
A first epitaxial structure layer and a second epitaxial structure layer are sequentially stacked on a first substrate
Implementation Method 2
The second epitaxial structure layer from a first side and the first epitaxial structure layer from a second side are etched to form a plurality of first micro-light-emitting elements and a plurality of second micro-light-emitting elements
Implementation Method 3
The plurality of the first micro-light-emitting elements and the plurality of the second micro-light-emitting elements are covered with a conductive layer, so that the plurality of the first micro-light-emitting elements and the plurality of the second micro-light-emitting elements are bonded to a control panel through the conductive layer
Implementation Method 4
The conductive layer is patterned to be etched to expose the control panel, wherein the conductive layer is etched and divided into a plurality of first conductive layers and a plurality of second conductive layers
Data Source
AI summary
A fabrication method for a display device includes the following operation. A first epitaxial structure layer and a second epitaxial structure layer are sequentially stacked on a first substrate. The second epitaxial structure layer and the first epitaxial structure layer are etched to form first micro-light-emitting elements and second micro-light-emitting elements. The first micro-light-emitting elements and the second micro-light-emitting elements are covered with a conductive layer. The conductive layer is patterned to be etched to expose the control panel. The conductive layer is divided into first conductive layers and second conductive layers. The first micro-light-emitting elements are correspondingly disposed in the first conductive layers. The second micro-light-emitting elements are correspondingly disposed in the second conductive layers. The first conductive layers disposed on the control panel and the second conductive layers disposed on the control panel are separated from each other and are electrically insulated from each other.