Micro-LED Display Height-Differentiated Repair
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Solution Overview
Problem
During the manufacturing of micro-LED displays, the transfer process for repairing abnormal LED elements can damage normal elements on the driving backplane, affecting yield due to the lack of a safe and efficient method for distinguishing and replacing defective elements.
Innovation Solution
The display apparatus design includes a driving backplane with conductive patterns and pad sets, where the distance between the top surface of light-emitting elements and their respective conductive connections varies, allowing for the differentiation and safe transfer of normal and abnormal elements, with abnormal elements having additional features like color conversion patterns or thicker structures to prevent damage during repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mass transfer is used to transfer LED elements to the driving backplane, then manufacturing efficiency is improved, but normal LED elements may be damaged during the transfer process
Solution Approach 1:
The patent applies local quality by creating different height levels for different LED elements on the driving backplane. Normal LED elements maintain their original height, while repaired LED elements are positioned at a different height level. This local differentiation allows the transfer head to selectively interact with repaired elements without damaging normal elements during the mass transfer process, thus resolving the contradiction between manufacturing efficiency and element integrity.
2Reliability
If repair transfer is performed to replace abnormal LED elements, then display quality is improved, but normal LED elements may be accidentally damaged
Solution Approach 1:
The patent implements local quality by creating distinct height levels for repaired LED elements compared to normal elements. The transfer head is designed to operate at a specific height that allows it to pick up and place repaired elements without contacting normal elements. This localized height differentiation eliminates the harmful effect of accidental damage to normal elements during repair operations while maintaining improved display quality.
3Measurement precision
If LED elements are arranged in a dense array for high resolution, then display resolution is improved, but the risk of damage during transfer increases
Solution Approach 1:
The patent resolves this contradiction by introducing local height differentiation among LED elements in the dense array. Even though elements are densely arranged for high resolution, repaired elements are positioned at a different height level than normal elements. This allows the transfer head to selectively access repaired elements without accidentally contacting densely packed normal elements, thus maintaining high resolution while reducing transfer damage risk.
Data Source
AI summary
A display apparatus includes a driving backplane and light-emitting elements. The driving backplane includes a substrate, pixel driving circuits, and a conductive layer. The conductive layer has conductive patterns respectively electrically connected to the pixel driving circuits. The light-emitting elements are respectively electrically connected to the conductive patterns. The light-emitting elements includes a first light-emitting element and a second light-emitting element. The conductive patterns includes a first conductive pattern and a second conductive pattern respectively electrically connected to the first light-emitting element and the second light-emitting element. A first distance is between a top surface of the first light emitting element and the first conductive pattern. A second distance is between a top surface of the second light emitting element and the second conductive pattern. The second distance is greater than the first distance.