AMOLED Pixel Circuit Sensing via Periodic Scan-Line Segmentation
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Solution Overview
Problem
Active matrix organic light emitting diode (AMOLED) display panels face challenges in accurately presenting gray scale/luminance due to process variations and aging differences among pixel circuits, necessitating real-time sensing and compensation of pixel circuit characteristics.
Innovation Solution
An apparatus and method that divide a scan-line period into a test data period and a display data period, where test data is written and electrical characteristics are sensed during the test period, and display data is written without sensing during the display period, allowing for real-time sensing of pixel circuit characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous sensing of pixel circuits is performed, then measurement precision is improved, but productivity deteriorates due to time consumption
Solution Approach 1:
The patent applies periodic action by dividing the scan-line period into distinct test data period and display data period. Sensing operations are performed periodically during the test data period rather than continuously, allowing the display to refresh at normal rates while still achieving accurate periodic measurements of pixel circuit characteristics.
Solution Approach 2:
The patent segments the scan-line period into separate test data period and display data period. This segmentation allows independent optimization of sensing operations during the test period and display operations during the display period, resolving the conflict between measurement precision and productivity.
2Measurement precision
If sensing operations are performed during display data period, then measurement precision is improved, but device complexity increases due to additional control circuits
Solution Approach 1:
The patent merges the sensing circuit with the existing source driving circuit, allowing the same circuit to perform both display driving and sensing functions by switching between test data and display data modes. This integration avoids the need for completely separate sensing circuits, thereby reducing overall device complexity.
Solution Approach 2:
The source driving circuit is designed with multi-functionality to serve both as a display driver and a sensing circuit. By configuring the circuit to operate in different modes (display mode and sensing mode), the patent eliminates the need for dedicated separate circuits, reducing device complexity while maintaining sensing precision.
3Manufacturing precision
If test data is continuously written to all pixel circuits, then manufacturing precision is improved through comprehensive sensing, but loss of time increases due to extended test period
Solution Approach 1:
The patent applies partial action by performing sensing operations on a subset of pixel circuits during the test data period rather than continuously on all circuits. This approach achieves sufficient manufacturing precision for quality control while minimizing the time lost to testing, as comprehensive sensing can be performed at reduced frequency.
Data Source
AI summary
An apparatus and a method for sensing a display panel are provided. The apparatus includes a source driving circuit and a sensing circuit. The source driving circuit is coupled to data lines to drive the pixel circuits according to a scan-line period for scanning one of the scan lines. The sensing circuit is coupled to a plurality of pixel circuits. The sensing circuit senses characteristics of the pixel circuits according to the scan-line period for scanning one of the scan lines, wherein the scan-line period comprises a display data period and a test data period. In the test data period, a corresponding pixel circuit receives test data, and the sensing circuit senses the electrical characteristic of the corresponding pixel circuit. In the display data period, the corresponding pixel circuit receives display data from a corresponding data line, and the sensing circuit does not sense the corresponding pixel circuit.