Display Device Optical Compensation Eliminates Stain Phenomenon
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Solution Overview
Problem
Existing display devices face issues with uneven characteristics of thin film transistors leading to luminance variations, resulting in a stain phenomenon when displaying high grayscale values, as current optical compensation methods cannot adequately adjust luminance below the maximum value.
Innovation Solution
An optical compensation method that involves providing test data to measure pixel luminance, calculating a compensation grayscale value based on a target luminance lower than the maximum, and performing a multi-time program to adjust gamma voltage, ensuring consistent luminance across the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the optical compensation method uses the maximum grayscale value to compensate luminance, then the luminance compensation effectiveness is improved, but the grayscale value cannot be increased beyond the maximum grayscale value, causing a stain phenomenon
Solution Approach 1:
The patent introduces a new dimension of control by separating luminance compensation from grayscale value adjustment. Instead of trying to increase grayscale values beyond the maximum (one-dimensional approach), the patent uses gamma voltage adjustment (a different dimension/parameter) to achieve luminance compensation while maintaining the maximum grayscale value constraint. This dimensional shift resolves the contradiction by providing an alternative control path.
Solution Approach 2:
The patent changes the control parameter from grayscale value to gamma voltage. By adjusting the gamma voltage independently of the grayscale value, the system can compensate for luminance variations without exceeding the maximum grayscale value limit. This parameter substitution allows simultaneous achievement of luminance compensation and grayscale value constraint maintenance.
2Device complexity
If the display device uses thin film transistors with crystallization process, then the device complexity is reduced, but the transistor characteristics become uneven, causing luminance variation
Solution Approach 1:
The patent implements a self-compensation mechanism where the display device automatically detects and corrects its own luminance variations through the optical compensation method. The system measures actual luminance output and adjusts gamma voltages accordingly, allowing the device to self-correct the uneven characteristics caused by the crystallization process without requiring more complex fabrication methods.
Solution Approach 2:
The patent establishes a feedback loop that measures the actual luminance output of pixels and uses this information to adjust gamma voltages. This feedback mechanism compensates for the uneven transistor characteristics by continuously monitoring and correcting luminance variations, thereby maintaining uniform display quality despite the simplified crystallization fabrication process.
3Illumination intensity
If the optical compensation method compensates grayscale value for high luminance, then the luminance uniformity is improved, but the compensation cannot be applied to low luminance areas, causing stain phenomenon
Solution Approach 1:
The patent creates a universal compensation mechanism that works across the entire luminance range, not just for high luminance values. By using gamma voltage adjustment as the compensation method, the system can effectively compensate for luminance variations regardless of whether the display is showing high or low luminance content, thereby eliminating the stain phenomenon across all grayscale values.
Data Source
AI summary
An optical compensation method for a display device including a pixel is provided. The method includes: providing test data having a first grayscale value to the display device; measuring a luminance of the pixel which emits light based on the test data; and calculating a compensation grayscale value based on a second target luminance and the measured luminance of the pixel. The second target luminance is lower than a first target luminance which is set based on the first grayscale value.