Pixel Voltage Sensing and Rewrite Compensation for Horizontal Line Suppression
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Solution Overview
Problem
Display devices experience a phenomenon where horizontal lines are visually perceived due to variations in threshold voltage and mobility characteristics of driving transistors and light-emitting elements over time, which existing external compensation circuits fail to adequately address.
Innovation Solution
A display device design that includes a timing controller to compensate for pixel degradation by calculating correction grayscale values during vertical blank periods, using sensing data to adjust image data and suppress luminance differences through rewrite image data during specific periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external compensation circuit is used to compensate for pixel degradation, then pixel degradation compensation is improved, but horizontal line artifact is generated
Solution Approach 1:
The patent applies preliminary action by measuring the initialization voltage during the vertical blank period before the active period begins. The timing controller predicts the initialization voltage for the active period based on the vertical blank period measurement, and generates rewrite image data in advance to compensate for pixel degradation before the actual display occurs, thus preventing the horizontal line artifact from appearing.
Solution Approach 2:
The patent implements feedback by measuring the actual initialization voltage during the vertical blank period and using this measurement to predict the initialization voltage for the active period. The timing controller then adjusts the rewrite image data based on the difference between predicted and actual voltages, creating a closed-loop compensation system that eliminates the horizontal line artifact.
2Measurement precision
If initialization voltage is measured during active period, then compensation accuracy is improved, but display quality deteriorates
Solution Approach 1:
The patent performs the initialization voltage measurement during the vertical blank period before the active display period begins. This preliminary measurement allows the system to capture accurate voltage data without interfering with the active display, thus maintaining both measurement precision and display quality.
Solution Approach 2:
The patent utilizes the periodic vertical blank period to perform measurements and calculations that would otherwise interfere with the active display. By scheduling the initialization voltage measurement during the natural periodic blanking interval, the system achieves accurate compensation without degrading display quality during the active period.
Data Source
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AI summary
A display device includes a plurality of pixels, a power supply, a voltmeter, and a timing controller. The power supply is configured to generate an initialization voltage to be supplied to a sensing pixel among the pixels. The voltmeter is configured to measure a first value of the initialization voltage supplied to the sensing pixel during an active period of a frame period and a second value of the initialization voltage supplied to the sensing pixel during a vertical blank period of the frame period. The timing controller is configured to generate rewrite image data that is supplied to the sensing pixel during the vertical blank period. The rewrite image data is generated from image data applied to the pixels during the active period and a difference between the first and second values.