LED Microchip Transfer Alignment and Light Control
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Solution Overview
Problem
Existing methods for manufacturing LED-based emissive display devices face challenges in improving the connection and integration of microchips with transfer substrates, leading to inefficiencies in electric injection and light emission.
Innovation Solution
A method involving the formation of control circuits and LED stacks on semiconductor substrates, with peripheral trenches and ring-shaped metallization to enhance electrical connection and light efficiency, and the use of conformal deposition and removal of insulating layers to access semiconductor layers, followed by cutting and affixing microchips onto transfer substrates with precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microchips are placed on transfer substrate with connection surfaces facing each other, then electric connection areas can be connected, but alignment precision and connection reliability are difficult to improve
Solution Approach 1:
The patent applies preliminary action by forming protrusions on the transfer substrate and corresponding recesses on the microchip connection surfaces before the actual placement. These pre-formed geometric features automatically guide and align the microchips during placement, ensuring precise alignment and reliable electrical connections without requiring complex alignment procedures during the placement process itself.
Solution Approach 2:
The patent introduces protrusions and recesses as intermediary geometric features that mediate the connection between the transfer substrate and microchips. These intermediaries provide mechanical guidance and positioning, facilitating both alignment precision and connection reliability by creating a self-aligning interface during the placement process.
2Object-generated harmful factors
If peripheral trenches are formed to surround control circuit and LED, then lateral light emission is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by forming peripheral trenches that divide and isolate the LED structure from its surroundings. These trenches segment the light emission paths, confining light primarily to the desired direction and reducing lateral emission. The segmentation is achieved through controlled etching that creates physical barriers without requiring complex additional components.
Solution Approach 2:
The patent applies local quality by creating specific geometric features (protrusions and recesses) at critical locations where connections are made, while forming peripheral trenches at edges where light emission needs control. This targeted approach addresses specific problems (alignment and lateral light emission) without unnecessarily complicating the entire device structure.
3Use of energy by moving object
If ring-shaped metallization is formed in trenches to contact first semiconductor layer, then electric injection is improved, but manufacturing steps increase
Solution Approach 1:
The patent applies dimensionality change by transitioning from planar electrode contacts to three-dimensional ring-shaped metallization structures formed within vertical trenches. This vertical integration allows the metallization to contact the first semiconductor layer along the trench walls, providing enhanced electrical injection efficiency through increased contact area and improved current distribution, while the trench structure itself provides the necessary dimensional framework.
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 improves electric injection and light efficiency, reduces lateral light emission, and simplifies the alignment process during microchip transfer, resulting in a more efficient and directed light emission in LED-based emissive display devices.
Implementation Method 1
forming in each trench a ring-shaped metallization in contact with the first semiconductor layer of the LED stack along the entire length of the trench
Implementation Method 2
Each microchip comprises a stack of a LED and of a circuit for controlling the LED
Implementation Method 3
an inorganic semiconductor LED
Data Source
AI summary
A method of manufacturing elementary chips of a LED-based emissive display device, each chip including an inorganic semiconductor LED, a circuit for controlling the LED, and a plurality of areas of connection to an external device arranged on a connection surface of the chip.