Micro LED Array Transfer With Ultrasonic Bonding for High-Yield Displays
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Solution Overview
Problem
The manufacturing of display devices using micro LEDs as display elements faces challenges such as high manufacturing costs and long production times, especially as the number of pixels increases and resolution becomes higher.
Innovation Solution
A method for manufacturing a display device that involves forming transistors in a matrix over a substrate, connecting conductors to the transistors, and forming light-emitting elements in a matrix over a film, with the conductors and light-emitting element electrodes being electrically connected using an extrusion mechanism and ultrasonic bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If micro LEDs are mounted individually on a circuit board, then the display device can be manufactured with high precision, but the manufacturing time becomes excessively long and costs increase
Solution Approach 1:
The patent segments the micro LED mounting process into two distinct stages: first, forming LED arrays on a separate substrate with precise positioning; second, transferring the entire array to the circuit board. This segmentation allows each stage to be optimized independently, resolving the contradiction between precision and speed.
Solution Approach 2:
The patent performs preliminary actions by pre-forming the LED arrays on a dedicated substrate before final mounting. The arrays are prepared with precise spacing and positioning in advance, allowing for rapid transfer to the circuit board later, thus improving manufacturing speed without sacrificing precision.
2Measurement precision
If the number of pixels in the display device is increased, then the resolution is improved, but the number of LEDs to be mounted increases and manufacturing time becomes longer
Solution Approach 1:
The patent merges multiple individual LED mounting operations into a single array transfer operation. By combining numerous LEDs into pre-formed arrays that can be transferred as units, the manufacturing time does not increase linearly with the number of pixels, enabling high resolution displays to be manufactured efficiently.
3Measurement precision
If the resolution of the display device becomes higher, then the display quality is improved, but it becomes more difficult to mount LEDs with required precision
Solution Approach 1:
The patent introduces an intermediary substrate as a mediator between the LED fabrication process and the final circuit board assembly. This intermediate substrate allows for precise LED array formation under controlled conditions, then facilitates easier transfer to the final display structure, reducing mounting difficulty 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 reduces manufacturing costs and increases yield, enabling the production of display devices with high luminance, contrast, response speed, and low power consumption.
Implementation Method 1
an ultrasonic wave is applied to the conductor and the electrode through the extrusion mechanism, whereby the conductor and the electrode are pressure-bonded
Data Source
AI summary
To reduce the manufacturing cost of a display device using a micro LED as a display element. To manufacture a display device using a micro LED as a display element in a high yield. Employed is a method for manufacturing a display device, including: forming a plurality of transistors in a matrix over a substrate (800), forming conductors (21, 23) electrically connected to the transistors over the substrate (800), and forming a plurality of light-emitting elements (51) in a matrix over a film (927). Each of the light-emitting elements (51) includes electrodes (85, 87) on one surface and the other surface is in contact with the film (927). The conductors (21, 23) and the electrodes (85, 87) are opposed to each other. An extrusion mechanism (929) is pushed out from the film (927) side to the substrate (800) side so that the conductors (21, 23) and the electrodes (85, 87) are in contact with each other, whereby the conductors (21, 23) and the electrodes (85, 87) are electrically connected to each other.