Universal Spare Pixel Circuit for OLED Display Yield
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Solution Overview
Problem
The challenge in organic light-emitting display apparatuses is the reduction of yield due to complex pixel circuits and difficult manufacturing processes, particularly in large-sized and high-resolution displays, where spare pixel circuits for repairing defective pixels occupy significant space.
Innovation Solution
The implementation of an organic light-emitting display apparatus with a spare pixel circuit in a repair area outside the display area, connected to a repair line that can supply driving current to defective emission pixels, utilizing a network of transistors and capacitors to enable effective pixel repair without requiring separate circuits for each sub-emission pixel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spare pixel circuits are provided for each sub-emission pixel to repair defective pixels, then reliability is improved, but device complexity increases and area is consumed
Solution Approach 1:
The spare pixel circuit is designed with multiple driving transistors (first, second, and third driving transistors) that can be selectively activated to repair different types of pixel defects. The same spare pixel circuit can function as a replacement for any sub-emission pixel by controlling different driving transistors, making it a universal repair solution rather than requiring dedicated spare circuits for each pixel type.
Solution Approach 2:
Multiple repair functions are merged into a single spare pixel circuit. Instead of having separate spare circuits for each sub-emission pixel, the patent combines multiple driving transistors within one spare pixel circuit to handle various defect scenarios, thereby reducing overall device complexity while maintaining comprehensive repair capability.
2Reliability
If spare pixel circuits are provided for each sub-emission pixel, then reliability is improved, but area occupied by repair region increases
Solution Approach 1:
A single spare pixel circuit with multiple driving transistors serves as a universal repair unit for all sub-emission pixels. This multi-functional design eliminates the need for multiple separate spare circuits, significantly reducing the area occupied by the repair region while maintaining the ability to repair any defective pixel in the display area.
Solution Approach 2:
The patent merges multiple repair functions into one compact spare pixel circuit located in the repair area. By combining multiple driving transistors and their associated control logic into a single circuit unit, the physical space required for repair functionality is minimized, allowing more area to be allocated to the active display region.
3Reliability
If complex pixel circuits are used to handle defects, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements local quality by providing repair functionality only in the dedicated repair area rather than duplicating complex repair circuits throughout the entire display area. The spare pixel circuit in the repair area contains the necessary driving transistors and control logic to manage defects, while the main display area maintains simpler pixel circuits, thereby reducing overall manufacturing precision requirements.
Solution Approach 2:
The complex repair circuitry is extracted from the main pixel structure and relocated to a separate repair area. By taking out the multiple driving transistors and repair logic from individual pixel circuits and concentrating them in a dedicated spare pixel circuit, the patent simplifies the manufacturing process for the majority of pixels while maintaining comprehensive defect management capability in the extracted repair section.
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 solution reduces dead space by allowing a single spare pixel circuit to serve multiple sub-emission pixels, enhancing the display's efficiency and reducing the impact of defective pixels on overall display quality and manufacturing yield.
Implementation Method 1
an emission device for emitting light by using the driving current
Data Source
AI summary
An organic light-emitting display apparatus includes an emission pixel in a display area and a spare pixel circuit in a repair area outside the display area. The emission pixels includes a plurality of sub emission pixels each including a driving unit for generating a driving current corresponding to input data signals and an emission device for emitting light by using the driving current. The spare pixel circuit is coupled to a repair line that is coupled to the emission device of one of the sub emission pixels. The spare pixel circuit includes a plurality of driving transistors corresponding to the plurality of sub emission pixels.