Micro-transfer Printed LED Display Substrates
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Solution Overview
Problem
Existing methods for electrically interconnecting small integrated circuits or light-emitting diodes to destination substrates are costly and complex, requiring multiple manufacturing steps and being prone to faults due to topographical differences between the circuits and substrates.
Innovation Solution
Micro-transfer printing of electronic components with protruding connection posts that are forcibly wedged into contact pads on the destination substrate, optionally with additional heat treatment or adhesive for secure bonding, allowing for direct and robust electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional methods (sputtering, spin-coating, photolithography) are used to form electronically active circuits on substrates, then the circuits can be distributed over the substrate, but the manufacturing process becomes complex and costly, and substrate material choices are limited
Solution Approach 1:
The invention segments the circuit formation process into two independent parts: (1) forming circuits on a first substrate using conventional methods, and (2) transferring the completed circuits to a second substrate. This segmentation allows each substrate to be optimized for its specific function without compromising the other, simplifying the overall manufacturing process while reducing complexity.
Solution Approach 2:
The invention performs preliminary actions by completing all circuit formation, processing, and testing on the first substrate before transfer. This includes forming semiconductor layers, patterning, metallization, and functional testing. By completing these actions beforehand, the transfer process becomes a simple mechanical operation rather than a complex multi-step process.
2Reliability
If thin-film transistor processing methods are used to improve electron mobility, then electronic characteristics are enhanced, but substrate material choices are limited by processing requirements
Solution Approach 1:
The invention separates the circuit fabrication substrate from the final application substrate. The first substrate can be optimized for processing compatibility (glass, silicon, etc.) while the second substrate is optimized for the application (flexible plastic, transparent substrate, etc.). This segmentation resolves the conflict between processing requirements and material versatility.
Solution Approach 2:
The first substrate acts as an intermediary that enables complex processing to be performed under optimal conditions, then transfers the completed circuits to the final substrate. This intermediary approach allows the use of conventional substrates for manufacturing while enabling innovative substrate materials for the final product.
3Productivity
If conventional assembly technologies are used to place components on substrates, then electronically active components can be distributed, but manufacturing costs increase and productivity decreases
Solution Approach 1:
The invention merges multiple discrete components and their interconnections into a single integrated circuit unit formed on the first substrate. This consolidation eliminates the need for separate assembly steps for each component, significantly improving productivity and reducing manufacturing costs through batch processing.
Solution Approach 2:
All component fabrication, interconnection formation, and testing are performed in advance on the first substrate before transfer. This preliminary completion of all manufacturing operations eliminates time-consuming on-site assembly steps, thereby improving productivity and reducing overall manufacturing costs.
Data Source
AI summary
A micro-printed display includes a display substrate. An array of row conductors, an array of column conductors, and a plurality of micro-pixels are disposed on the display substrate. Each micro-pixel is uniquely connected to a row and a column conductor and comprises a pixel substrate separate from the display substrate and the pixel substrate of any other micro-pixel. Pixel conductors are patterned on each pixel substrate and one or more LEDs are disposed on or over the pixel substrate. Each LED is electrically connected to one or more of the pixel conductors and has an LED substrate separate from any other LED substrate, the display substrate, and any pixel substrate. A pixel controller disposed on the pixel substrate can control the LEDs. The micro-pixel can be electrically connected to the display substrate with connection posts. Redundant or replacement LEDs or micro-pixels can be provided on the pixel or display substrate.