Light Emitting Display Pixel Driving Circuit Threshold Voltage Compensation
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Solution Overview
Problem
As light emitting display apparatuses develop to have high resolution, the time allocated for sensing the threshold voltage of driving transistors decreases, leading to reduced sensing performance and deterioration of image quality due to the limited ability to compensate for transistor degradation.
Innovation Solution
The light emitting display apparatus uses three scan signals, with two supplied through two scan lines in one pixel and the third through an adjacent pixel, allowing for accurate detection and compensation of the threshold voltage during two or more horizontal periods, even with reduced pixel width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the display apparatus is developed to have high resolution, then the pixel density is improved, but the time allocated for sensing the threshold voltage decreases
Solution Approach 1:
The sensing process is divided into multiple horizontal periods (at least two) instead of attempting to complete it in a single period. This segmentation allows the threshold voltage sensing to be performed in stages, with each horizontal period contributing to the overall sensing accuracy, thereby resolving the conflict between high resolution requirements and sufficient sensing time.
2Manufacturing precision
If the pixel width is reduced for high resolution, then the display detail is improved, but the sensing performance deteriorates
Solution Approach 1:
The sensing operation is performed in advance during horizontal periods before the actual display refresh is completed. By utilizing the horizontal periods for threshold voltage sensing in advance, the system ensures that accurate sensing data is available before the pixel width constraints of high-resolution displays become limiting factors.
3Reliability
If more transistors are added for internal compensation, then the compensation accuracy is improved, but the device complexity increases
Solution Approach 1:
The pixel driving circuit performs self-compensation by utilizing its own existing transistors and components to sense and compensate for threshold voltage variations. The circuit uses its inherent structure to automatically detect and correct degradation without requiring additional external compensation components, thereby maintaining high compensation accuracy while avoiding increased device complexity.
Data Source
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AI summary
Disclosed is a light emitting display apparatus in which two of three scan signals used by a pixel driving circuit provided in one pixel are supplied through two scan lines provided in the pixel and the other remaining signal is supplied through a scan line provided in another pixel adjacent to the pixel.