Antifuse-Programmed Redundant Subpixels for Micro LED Displays
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Solution Overview
Problem
The fabrication of micro LED displays poses challenges due to the need for incorporating hundreds, thousands, or millions of micro LEDs simultaneously, which is costly and inefficient, and there is a requirement for methods to replace defective micro LEDs or subpixels during manufacturing to achieve defect-free or low-defect displays.
Innovation Solution
The implementation of a pixel structure with redundant subpixels, where unprogrammed antifuses electrically isolate subpixels until tested for functionality, allowing functional redundant subpixels to replace defective ones by programming the antifuses, enabling the connection of subpixels to circuitry and ensuring the display's functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pick-and-place tools are used to incorporate micro LEDs into a display, then individual micro LEDs can be placed with precision, but the fabrication speed is too slow and cost is prohibitive for displays with millions of micro LEDs
Solution Approach 1:
The patent merges multiple micro LEDs onto a single substrate in arrays, allowing hundreds, thousands, or millions of micro LEDs to be incorporated simultaneously into the display using wafer-level or array-level transfer techniques rather than individual pick-and-place operations. This combining approach maintains placement precision while dramatically increasing fabrication throughput.
Solution Approach 2:
The patent segments the display fabrication process into separate stages: first fabricating and testing micro LED arrays on a substrate, then transferring selected arrays or individual micro LEDs to the display in bulk. This segmentation allows for efficient bulk transfer while maintaining the ability to select only functional micro LEDs.
2Reliability
If standard size LEDs are fabricated and tested individually before incorporation into a display, then defective LEDs can be identified and removed, but this approach is not feasible for micro LEDs that must be incorporated in large numbers simultaneously
Solution Approach 1:
The patent combines multiple micro LEDs into arrays on a single substrate, allowing bulk electrical testing of hundreds, thousands, or millions of micro LEDs simultaneously through matrix addressing techniques. This enables defect identification at the array level without requiring individual testing, maintaining reliability while dramatically improving fabrication efficiency.
Solution Approach 2:
The patent performs preliminary fabrication and electrical testing of micro LED arrays on a substrate before incorporation into the final display. This preliminary action allows for identification and elimination of defective micro LEDs or entire arrays before they are transferred to the display, ensuring high reliability while maintaining efficient bulk processing.
3Reliability
If redundant subpixels are included in the pixel structure with antifuse programming capability, then defective subpixels can be replaced during manufacturing, but the device complexity and fabrication process are increased
Solution Approach 1:
The patent incorporates redundant subpixels and antifuse structures during the initial fabrication process, before the display is completed. This preliminary preparation allows for later programming of antifuses to bypass defective subpixels or activate redundant ones, improving display quality without requiring complex post-fabrication modifications.
Solution Approach 2:
The patent uses antifuses as intermediary elements between the subpixel control circuitry and the subpixels themselves. These antifuses can be programmed to either connect or disconnect specific subpixels from their control signals, providing a simple mechanism for defect replacement that adds minimal complexity to the overall pixel structure.
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 allows for the production of cost-effective, high-resolution, energy-efficient micro LED displays with reduced defects by enabling the replacement of defective subpixels during manufacturing, improving the efficiency and quality of micro LED display fabrication.
Implementation Method 1
an antifuse disposed between a select line and the control circuit
Implementation Method 2
Each first group subpixel comprises at least one first group LED
Data Source
AI summary
Devices and methods of their fabrication for pixels or displays are disclosed. Pixels and displays having redundant subpixels are described. Subpixels are initially isolated by an unprogrammed antifuse. A subpixel is connected to the display by programming the antifuse, electrically connecting it to the pixel or display. Defective subpixels can be determined by photoluminescent testing or electroluminescent testing, or both. A redundant subpixel can replace a defective subpixel before pixel or display fabrication is complete.