Micro LED Transfer Method Using Light-Shielding Layer
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Solution Overview
Problem
The existing methods for manufacturing micro LED display devices are time-consuming and prone to connection defects, leading to low yield as the number of micro LEDs increases with higher image quality.
Innovation Solution
A method for manufacturing an image display device that involves preparing a substrate with a semiconductor layer, forming a light-shielding layer and insulating films, bonding the semiconductor layer to a circuit substrate, and etching to form light-emitting elements, which are then electrically connected to the circuit elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If many micro LEDs are individually formed and sequentially transferred to a substrate, then higher image quality such as full HD, 4K, 8K can be achieved, but an enormous amount of time is necessary for the transfer process and connection defects may occur
Solution Approach 1:
The semiconductor layer is divided into multiple regions corresponding to different colors (red, green, blue) and each region is processed separately. This segmentation allows parallel processing of different color regions, significantly reducing the total transfer time while maintaining high image quality through precise regional control
Solution Approach 2:
The semiconductor layer is formed and prepared in advance on a temporary substrate before the final transfer to the display substrate. This preliminary formation allows for pre-alignment and pre-positioning of micro LEDs, eliminating time-consuming alignment operations during the final transfer process
2Manufacturing precision
If many micro LEDs are individually formed and sequentially transferred to a substrate, then higher image quality such as full HD, 4K, 8K can be achieved, but connection defects between micro LEDs and drive circuits may occur leading to decreased yield
Solution Approach 1:
Multiple micro LEDs of different colors are merged into a single integrated semiconductor layer structure. This merging allows all micro LEDs to be formed and positioned simultaneously in a single processing step, eliminating sequential transfer operations that cause connection defects and improving overall yield
Solution Approach 2:
A temporary substrate serves as an intermediary carrier that holds the semiconductor layer during formation and processing. This intermediary allows for precise alignment and stable transfer of micro LEDs to the final substrate, reducing connection defects by providing a controlled intermediate state
3Manufacturing precision
If individually-formed micro LEDs are sequentially transferred to a substrate, then high-resolution display can be achieved, but the manufacturing process becomes complex and time-consuming
Solution Approach 1:
The semiconductor layer containing multiple micro LEDs is formed and prepared in advance on a temporary substrate before final transfer. This preliminary action consolidates multiple individual formation steps into a single process, reducing manufacturing complexity while achieving high display resolution
Solution Approach 2:
Instead of transferring individual micro LEDs sequentially to the substrate, the process is inverted by first forming all micro LEDs on a temporary substrate and then transferring the complete semiconductor layer as a unit. This inversion dramatically reduces process complexity while maintaining high resolution
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 method shortens the transfer process of light-emitting elements and increases yield, making it feasible to produce high-quality image display devices with micro LEDs at a realistic cost.
Implementation Method 1
a light-shielding layer located between the light-emitting element and the circuit element
Implementation Method 2
bonding the semiconductor layer to the second substrate on which the insulating film is formed
Data Source
AI summary
An image display device includes: a circuit element; a first wiring layer electrically connected to the circuit element; a first insulating film covering the circuit element and the first wiring layer; a light-emitting element located on the first insulating film; a light-shielding layer located in the first insulating film between the circuit element and the light-emitting element; a second insulating film covering at least a portion of the light-emitting element; and a second wiring layer located on the second insulating film and electrically connected to the light-emitting element. The light-emitting element includes a first semiconductor layer of a first conductivity type, a light-emitting layer located on the first semiconductor layer, and a second semiconductor layer located on the light-emitting layer, the second semiconductor layer being of a second conductivity type that is different from the first conductivity type. In a plan view, the light-shielding layer covers the circuit element.