Temporary Electrode Testing for Repairable Microdevice Displays
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Solution Overview
Problem
The challenge in micro device system integration is identifying and repairing defective micro devices after they are transferred to a system substrate, especially when the electrode is deposited post-placement, as it complicates testing and can damage the system.
Innovation Solution
Utilizing external electrodes, capacitive coupling structures, and fuses integrated into the system substrate to test and repair micro devices, along with spare circuits and repair pads to replace defective devices, and a defect mapping block to redirect data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electrode is deposited post-placement to connect micro devices, then system integration flexibility is improved, but testing complexity increases and system damage risk increases
Solution Approach 1:
The patent applies preliminary action by forming test contacts and test structures on the substrate before transferring the micro devices. This allows testing to be performed before the electrode deposition step, avoiding the complexity and damage risks associated with post-placement electrode deposition. The test contacts are integrated into the substrate structure in advance, enabling non-destructive testing while maintaining integration flexibility.
2Adaptability or versatility
If electrode is deposited post-placement to connect micro devices, then system integration flexibility is improved, but system damage risk increases
Solution Approach 1:
The patent performs testing before electrode deposition by using pre-formed test contacts on the substrate. This preliminary testing approach eliminates the need for post-placement electrode deposition, thereby avoiding the system damage risk associated with that process while preserving integration flexibility.
Solution Approach 2:
The patent introduces test contacts as intermediary structures that enable testing without requiring electrode deposition. These test contacts serve as mediators between the test equipment and the micro devices, allowing non-destructive testing to be performed before the electrode is deposited, thus avoiding system damage.
3Productivity
If redundant micro devices are used to increase yield, then manufacturing yield is improved, but manufacturing cost increases
Solution Approach 1:
The patent performs testing before electrode deposition and device integration, allowing defective micro devices to be identified and removed early in the process. This preliminary testing eliminates the need for redundant devices as a backup, since only functional devices proceed to integration, thereby improving yield without increasing cost.
Solution Approach 2:
The patent extracts defective micro devices from the production flow through preliminary testing, separating them from functional devices before electrode deposition. This extraction of defects prevents wasted electrode material and assembly resources on non-functional devices, improving overall yield without requiring redundant functional devices.
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
Enables efficient testing and cost-effective repair of micro devices by minimizing system damage and increasing yield without increasing costs.
Implementation Method 1
capacitive coupling structures
Implementation Method 2
measuring by the sensor or the sensor array the light output from the micro device generating measurements
Data Source
AI summary
What is disclosed are structures and methods for testing and repairing emissive display systems. Systems are tested with use of temporary electrodes which allow operation of the system during testing and are removed afterward. Systems are repaired after identification of defective devices with use of redundant switching from defective devices to functional devices provided on repair contact pads.