Micro LED Array Transfer Using Graphene and Via Wiring
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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 as the number of micro LEDs increases for higher image quality resolutions like 4K or 8K.
Innovation Solution
A method involving the formation of a graphene-including layer on a substrate with a circuit, followed by a semiconductor layer with a light-emitting layer, and subsequent etching to create a light-emitting element, which is then connected to a wiring layer and circuit using vias, reducing the transfer process time 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 transfer process becomes extremely time-consuming 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 allows the entire array of micro LEDs to be 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 contradiction by maintaining the self-luminous properties of micro LEDs while dramatically improving transfer efficiency and reducing connection defects.
Solution Approach 2:
The patent performs preliminary formation of the semiconductor layer containing all micro LEDs on a Si substrate before transfer to the drive circuit substrate. This preliminary action allows the entire micro LED array to be prepared in advance as an integrated structure, enabling batch transfer rather than sequential individual transfer. The preliminary formation of the semiconductor layer with embedded micro LEDs resolves the productivity issue while preserving the high luminance characteristics.
2Manufacturing precision
If individually-formed micro LEDs are sequentially transferred to a drive circuit substrate, then each micro LED can be precisely positioned, but connection defects between micro LEDs and drive circuits increase and yield decreases
Solution Approach 1:
The patent merges multiple micro LEDs into a single integrated semiconductor layer with internal connections already established. By transferring the entire semiconductor layer as one unit rather than individual micro LEDs, the connection points are minimized and standardized, reducing the probability of connection defects. The merging principle maintains positioning precision through the integrated structure while significantly improving connection reliability.
Solution Approach 2:
The patent introduces a Si substrate as an intermediary carrier that holds the entire semiconductor layer containing micro LEDs during the transfer process. This intermediary substrate allows the micro LEDs to be transferred as a unified structure with pre-established connections, reducing the risk of connection defects compared to direct sequential transfer. The intermediary substrate facilitates precise positioning while protecting the integrity of connections between micro LEDs and drive circuits.
3Measurement precision
If the number of micro LEDs is increased for higher image quality such as 4K or 8K, then the image resolution and quality improve, but the transfer process time increases enormously and manufacturing complexity increases
Solution Approach 1:
The patent merges thousands of micro LEDs into a single integrated semiconductor layer that can be transferred as one unit. This merging approach allows the manufacturing of high-resolution displays with thousands of micro LEDs without proportionally increasing transfer time, as the entire array is transferred simultaneously rather than sequentially. The principle directly addresses the time loss issue while enabling high image resolution through the integrated micro LED array.
Solution Approach 2:
The patent performs preliminary formation of the complete semiconductor layer containing all micro LEDs on a Si substrate before transfer. This preliminary action allows the entire high-resolution micro LED array to be prepared in advance as an integrated structure, enabling batch transfer to the drive circuit substrate. The preliminary formation eliminates the need for time-consuming sequential transfer operations, directly reducing transfer process time while maintaining high image resolution.
4Manufacturing precision
If individually-formed micro LEDs are sequentially transferred to a drive circuit substrate, then each connection can be individually verified, but the manufacturing cost increases and yield decreases
Solution Approach 1:
The patent merges multiple micro LEDs into an integrated semiconductor layer with standardized connection interfaces. This merging reduces the total number of connection points required during transfer, as the entire array connects through unified interfaces rather than requiring individual connection verification for each micro LED. The principle lowers manufacturing cost by reducing the complexity of connection verification while maintaining manufacturing precision through the integrated structure.
Solution Approach 2:
The patent introduces a Si substrate as an intermediary carrier that provides a standardized interface for the entire semiconductor layer. This intermediary simplifies the connection verification process by reducing the number of connection points from thousands of individual micro LED connections to a few standardized array-level connections. The intermediary substrate maintains manufacturing precision through standardized interfaces while significantly reducing manufacturing cost and improving yield.
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 of light-emitting elements, reduces connection defects, and enhances the manufacturing efficiency of high-definition image display devices by allowing for a more uniform and reliable electrical connection, thereby increasing yield and reducing costs.
Implementation Method 1
forming a graphene-including layer on the insulating film
Data Source
AI summary
A method for manufacturing an image display device includes: preparing a substrate, the substrate including a circuit and a first insulating film covering the circuit; forming a graphene-including layer on the first insulating film; forming a semiconductor layer on the graphene-including layer; forming a light-emitting element by etching the semiconductor layer, the light-emitting element including a bottom surface on the graphene-including layer, and a light-emitting surface at a side opposite to the bottom surface; forming a second insulating film covering the graphene-including layer, the light-emitting element, and the first insulating film; forming a first via extending through the first and second insulating films; and forming a wiring layer on the second insulating film. The first via is located between the wiring layer and the circuit and electrically connects the wiring layer and the circuit. The light-emitting element is electrically connected to the circuit via the wiring layer.