Display Device Light Stress Compensation for Transistor Stability
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Solution Overview
Problem
Display devices face issues with changes in transistor characteristics due to continuous light exposure, leading to luminance variations and after-images, especially when the gate-source voltage of the transistor is below the threshold voltage.
Innovation Solution
A display device with a light stress compensator that generates data voltage control signals to adjust the data voltage for sub-pixels based on input image data, using a black bias offset voltage to mitigate changes in transistor characteristics, and a data driver that varies data voltages across grayscale values to compensate for light-induced stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the display device operates continuously under light exposure, then the display can maintain normal function, but the transistor characteristics change leading to luminance variations and after-images
Solution Approach 1:
The patent applies preliminary action by applying a black bias offset voltage to the transistor before normal operation begins. This pre-biasing compensates for the light-induced threshold voltage shifts that will occur during operation, preventing luminance variations and after-images from the outset. The compensation is calculated based on expected light exposure conditions and applied in advance to maintain transistor characteristic stability throughout continuous operation.
2Use of energy by moving object
If the gate-source voltage of the transistor is reduced below threshold voltage, then power consumption decreases, but the change in transistor characteristics by light is accelerated
Solution Approach 1:
The patent employs parameter changes by dynamically adjusting the black bias offset voltage based on the actual gate-source voltage conditions and light exposure levels. When the gate-source voltage is reduced to save power, the system calculates and applies a corresponding compensation voltage that counteracts the accelerated light-induced characteristic changes. This allows the display to operate at lower power consumption levels while maintaining transistor stability through real-time parameter adjustment.
Data Source
AI summary
A display device includes a display panel including a first data line, a second data line, and a pixel, the pixel including a first sub-pixel coupled to the first data line, and a second sub-pixel coupled to the second data line, a light stress compensator configured to generate a first data voltage control signal for the first sub-pixel based on a second data value of input image data for the second sub-pixel, in response to a first data value of input image data for the first sub-pixel being equal to or less than a first reference value, and a data driver configured to generate a first data signal based on the first data value for the first sub-pixel, to provide a first data voltage to the first data line, and to vary the first data voltage based on the first data voltage control signal.