AMOLED Pixel Sensing Circuit Segmentation for Gray Scale Compensation
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Solution Overview
Problem
Active matrix organic light emitting diode (AMOLED) display panels face challenges in presenting consistent 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 divides a scan-line period into test data and display data periods, allowing the sensing circuit to measure electrical characteristics of pixel circuits during the test data period and write display data without sensing during the display data period, enabling real-time sensing of pixel circuit characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensing circuit continuously senses all pixel circuits during the entire scan-line period, then the measurement precision of pixel circuit characteristics is improved, but the productivity of the display panel is reduced due to excessive sensing time occupying the display time
Solution Approach 1:
The scan-line period is segmented into distinct time intervals: a test data period for sensing operations and a display data period for normal display operations. This temporal segmentation allows the sensing circuit to operate only during the test data period, reducing sensing time and minimizing impact on display productivity while maintaining measurement precision through dedicated sensing intervals.
Solution Approach 2:
The sensing operation is implemented as a periodic action occurring at specific intervals (during test data periods) rather than continuously. The sensing circuit periodically activates to measure pixel circuit characteristics during designated test windows, then remains inactive during display data periods, achieving a balance between measurement needs and display performance.
2Reliability
If the sensing circuit operates during the display data period, then the real-time sensing capability is improved, but the gray scale/luminance presentation accuracy deteriorates due to interference with normal display data writing
Solution Approach 1:
The operation timeline is segmented into separate test data periods and display data periods. During test data periods, the sensing circuit actively measures pixel characteristics while display operations are suspended. During display data periods, normal display operations proceed without sensing interference. This segmentation eliminates temporal overlap between sensing and display data writing, ensuring both real-time sensing capability and display accuracy.
Solution Approach 2:
Test data serves as an intermediary mechanism enabling sensing operations without affecting display data integrity. By writing test data during designated periods and using it for sensing measurements, the system obtains real-time pixel characteristics while preventing interference with actual display content, thus maintaining both sensing reliability and display precision.
Data Source
AI summary
An apparatus and a method for sensing a display panel are provided. The apparatus includes a gate driving circuit and a sensing circuit. The gate driving circuit may scan the scan-lines during a plurality of scan-line periods within a frame period. The sensing circuit is coupled to a plurality of pixel circuits. A corresponding scan-line period of the scan-line periods is divided into a test data period and a display data period. In the test data period, the sensing circuit controls a corresponding pixel circuit to receive the test data, and the sensing circuit senses the electrical characteristic of the corresponding pixel circuit. In the display data period, the sensing circuit controls the corresponding pixel circuit to receive the display data from a corresponding data line, and the sensing circuit does not sense the corresponding pixel circuit.