Graphene-Based Micro LED Display Fabrication Without Individual Transfer
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Solution Overview
Problem
The existing methods for manufacturing image display devices using micro LEDs are time-consuming and prone to connection defects, leading to reduced yield and high costs, especially for high-definition displays like 4K and 8K, due to the lengthy transfer process of individually forming and mounting micro LEDs on a substrate with a drive circuit.
Innovation Solution
A method involving the formation of a graphene-including layer on a substrate with a circuit element, followed by a semiconductor layer with a light-emitting layer, and the use of vias to electrically connect the wiring layers, allowing for the direct formation of light-emitting elements on a drive circuit substrate, reducing the transfer process and increasing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If individually-formed micro LEDs are sequentially transferred to a drive circuit substrate, then the display device can achieve high luminance and self-luminous properties, but the manufacturing time becomes excessively long and connection defects increase
Solution Approach 1:
The patent merges multiple micro LEDs into a single integrated semiconductor layer that is grown on a Si substrate. This consolidated structure is then transferred as one unit to the drive circuit substrate, eliminating the need for sequential individual transfer of each micro LED. The merging principle directly resolves the time consumption issue while preserving the self-luminous properties of the micro LEDs.
Solution Approach 2:
The patent performs preliminary formation of multiple micro LEDs within a single semiconductor layer on a Si substrate before transfer. This preliminary action allows all micro LEDs to be prepared in advance as an integrated structure, so that during the actual mounting process, the entire array is transferred in one operation rather than sequentially, significantly reducing manufacturing time.
2Illumination intensity
If individually-formed micro LEDs are sequentially transferred to a drive circuit substrate, then the display device can achieve high luminance, but the yield is reduced due to connection defects
Solution Approach 1:
By merging multiple micro LEDs into a single integrated semiconductor layer, the patent eliminates the repeated connection operations required for individual transfer. The consolidated structure reduces the number of connection points from thousands of individual micro LED connections to a single interface, thereby minimizing connection defects and improving yield.
Solution Approach 2:
The patent grows the entire array of micro LEDs as an integrated semiconductor layer on a Si substrate with proper electrical connections established beforehand. This preliminary integration acts as a cushioning measure, ensuring that all connections are formed in a controlled environment before transfer, reducing the risk of connection defects during the mounting process.
3Manufacturing precision
If many micro LEDs are individually formed and sequentially transferred, then the display resolution can be increased for full high definition and 4K, but the manufacturing complexity and cost increase enormously
Solution Approach 1:
The patent combines the formation of multiple high-resolution micro LEDs into a single integrated semiconductor layer growth process on a Si substrate. This merging approach maintains the high display resolution by preserving the fine pitch arrangement of micro LEDs while dramatically simplifying the manufacturing process by transferring the entire array as one unit rather than individually mounting each element.
Solution Approach 2:
The patent uses a Si substrate as a template or copy platform to grow the semiconductor layer containing multiple micro LEDs. This copying approach allows the complex high-resolution pattern to be replicated precisely on the Si substrate, which then serves as an intermediate carrier for transfer to the drive circuit substrate, simplifying the overall manufacturing process.
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 shortens the transfer process, reduces the number of manufacturing steps, and enhances the yield of high-definition image display devices by eliminating the need for individual micro LED transfer, thereby lowering production costs and improving the efficiency of light emission.
Implementation Method 1
a semiconductor layer that includes a light-emitting layer is grown on a Si substrate
Implementation Method 2
a light-emitting element that includes a light-emitting surface on the graphene-including layer
Data Source
AI summary
A method for manufacturing an image display device according to an embodiment includes: preparing a first substrate that includes a circuit element formed on a first surface of a substrate, a first wiring layer connected to the circuit element, and a first insulating film covering the circuit element and the first wiring layer; forming a graphene-including layer on the first insulating film; forming a semiconductor layer that includes a light-emitting layer on the graphene-including layer; forming a light-emitting element that includes a light-emitting surface on the graphene-including layer and includes a top surface at a side opposite to the light-emitting surface by patterning the semiconductor layer; forming a second insulating film covering the first insulating film, the graphene-including layer, and the light-emitting element; forming a first via extending through the first and second insulating films; and forming a second wiring layer on the second insulating film.