LED Transfer Method for Display Color Uniformity
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Solution Overview
Problem
The challenge in manufacturing large-screen display devices using LEDs is the uneven wavelength distribution of LEDs grown on a single wafer, leading to perceived color inconsistencies due to process errors, which affects color uniformity and increases manufacturing costs.
Innovation Solution
A method of transferring LEDs grown on a wafer onto a display panel in a way that alternates their placement in rows or columns, using multiple donors to minimize wavelength differences and improve color uniformity, allowing for the use of LEDs with larger allowable wavelength variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If LEDs are transferred one-to-one from wafer to donor to display panel, then the manufacturing process is simple, but color uniformity deteriorates due to wavelength differences
Solution Approach 1:
The patent segments the transfer process into two independent stages: first transferring LEDs from wafer to donor, then from donor to display panel. This segmentation allows for separate optimization of each transfer operation and enables the use of multiple donors to distribute LEDs with different wavelength characteristics across different regions, thereby improving color uniformity while maintaining manufacturing simplicity
Solution Approach 2:
The patent introduces a donor substrate as an intermediary between the wafer and the display panel. This intermediary allows for decoupling the wavelength distribution on the wafer from the final display arrangement, enabling LEDs with varying wavelengths to be redistributed across different spatial locations on the donor, which then gets transferred to the display panel in a pattern that minimizes visible color differences
2Ease of manufacture
If LEDs with different wavelengths are used to cover a wider range, then manufacturing cost decreases, but color uniformity deteriorates
Solution Approach 1:
The patent applies local quality by assigning LEDs with different wavelength characteristics to specific local regions on the display panel through the donor transfer mechanism. By controlling which LEDs from the wafer are transferred to which regions of the donor, the system can optimize local color characteristics to match the requirements of different display areas, thereby achieving good color uniformity even when using LEDs with broader wavelength variations
Solution Approach 2:
The patent changes the spatial distribution parameter of LEDs during the transfer process. By altering how LEDs are positioned on the donor substrate relative to their original positions on the wafer, the system can redistribute wavelength variations across the display area, transforming the problem from a wavelength uniformity issue into a spatial arrangement issue that can be solved through clever positioning
Data Source
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AI summary
Disclosed are a display device and a method of manufacturing a display device. The method of a display device according to an exemplary embodiment of the present disclosure includes: a first transferring step of transferring a plurality of LEDs disposed on a wafer onto a plurality of donors; and a second transferring step of transferring the plurality of LEDs transferred onto the plurality of donors onto a display panel, in which in the second transferring step, an area where one of the plurality of donors overlaps the display panel partially overlaps an area where the other one of the plurality of donors overlaps the display panel. Therefore, the plurality of LEDs having different wavelengths is uniformly transferred to reduce a boundary caused by the difference in wavelengths and improve color uniformity.