Micro LED Display Manufacturing Without Individual LED Transfer
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Solution Overview
Problem
The manufacturing of micro LED display devices is hindered by the time-consuming transfer process of individually formed micro LEDs to a drive circuit, which increases the risk of connection defects and reduces yield, especially with higher image quality demands.
Innovation Solution
A method involving the formation of a conductive layer with single-crystal metal, a semiconductor layer with a light-emitting layer, and a reduced transfer process that includes insulating films and wiring layers to enhance yield and reduce transfer steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If individually-formed micro LEDs are sequentially transferred to a drive circuit substrate, then the display device can achieve high image quality (full HD, 4K, 8K), but the transfer process becomes extremely time-consuming and connection defects increase
Solution Approach 1:
The invention divides the manufacturing process into two independent stages: (1) growing semiconductor layers with light-emitting elements on a first substrate, and (2) forming drive circuits on a second substrate, which are then bonded together. This segmentation allows parallel processing of light-emitting elements and drive circuits, eliminating the time-consuming sequential transfer of individually-formed micro LEDs while maintaining high image quality through precise control of each stage.
Solution Approach 2:
The invention performs preliminary actions by pre-growing complete semiconductor layers including light-emitting elements on the first substrate before bonding, and pre-forming all drive circuit components on the second substrate beforehand. This preliminary preparation enables simultaneous completion of both components, which are then bonded together in a single step, dramatically reducing the overall manufacturing time compared to sequential transfer methods.
2Manufacturing precision
If individually-formed micro LEDs are sequentially transferred to a drive circuit substrate, then the display device can achieve high image quality, but connection defects between micro LEDs and drive circuits increase, reducing yield
Solution Approach 1:
The invention segments the manufacturing process so that light-emitting elements are grown on a first substrate and drive circuits are formed on a second substrate independently, then bonded together. This eliminates the repeated pick-and-place transfer operations that cause connection defects, as each component is formed in its optimal environment and transferred only once as a complete unit.
Solution Approach 2:
The invention uses a bonding substrate as an intermediary that receives both the light-emitting element array from the first substrate and the drive circuit array from the second substrate, then facilitates their bonding. This intermediary approach ensures proper alignment and reduces connection defects by providing a controlled bonding interface rather than direct transfer between dissimilar substrates.
3Ease of manufacture
If a semiconductor layer is grown on a Si substrate with electrode formation and bonding to a circuit board, then the manufacturing process is simplified, but the transfer process of light-emitting elements remains time-consuming
Solution Approach 1:
The invention segments the manufacturing into parallel independent processes: growing semiconductor layers on a first substrate and forming drive circuits on a second substrate simultaneously, then bonding them together. This eliminates the sequential transfer bottleneck while maintaining the simplified approach of growing complete semiconductor structures on a substrate before final assembly.
Solution Approach 2:
The invention transitions from a planar sequential process to a three-dimensional stacked architecture where light-emitting elements and drive circuits are formed on separate substrates in parallel, then bonded vertically. This dimensional change enables simultaneous processing of both components without increasing process complexity, dramatically reducing transfer time while maintaining ease of manufacture.
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 reduces the transfer process of light-emitting elements and increases yield, resulting in a more efficient manufacturing process for micro LED display devices with improved luminance, viewing angle, and contrast.
Implementation Method 1
a conductive layer that includes a first part of a single-crystal metal
Implementation Method 2
a semiconductor layer that includes a light-emitting layer
Data Source
AI summary
A method for manufacturing an image display device includes: forming a conductive layer on a first substrate, wherein at least a part of the conductive layer is formed of a single-crystal metal; forming a semiconductor layer on said part of the conductive layer, the semiconductor layer comprising a light-emitting layer; forming a light-emitting element by patterning the semiconductor layer; forming a first insulating film that covers the first substrate, the conductive layer, and the light-emitting element; forming a circuit element on the first insulating film; forming a second insulating film that covers the first insulating film and the circuit element; exposing a surface that includes a light-emitting surface of the light-emitting element by removing a portion of the first insulating film and a portion of the second insulating film; and forming a wiring layer on the second insulating film.