Display Panel Driver With Degradation-Based Voltage Compensation
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Solution Overview
Problem
Display devices, such as OLED displays, experience luminance reduction due to the degradation of light emitting elements, which conventional methods fail to adequately compensate for by maintaining fixed power supply voltages, leading to incomplete luminance recovery and increased power consumption.
Innovation Solution
A display device that generates stress data representing pixel degradation, adjusts input image data, and dynamically adjusts power supply voltages based on luminance and degradation levels to compensate for luminance loss, using a panel driver with components like a degradation accumulating circuit, degradation compensating circuit, and driving voltage determining circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the driving voltage for light emitting elements is increased to compensate for luminance reduction due to degradation, then the luminance is restored, but the power consumption increases
Solution Approach 1:
The patent changes the voltage parameter dynamically by separating power supply into two levels: a first power supply voltage (ELVDD) that remains constant, and a second power supply voltage (ELVSS) that is adjusted based on degradation level. This allows precise control of the voltage difference applied to light emitting elements, compensating for luminance reduction while minimizing unnecessary power consumption that would result from uniformly increasing both voltage levels.
2Reliability
If conventional methods maintain fixed power supply voltages to simplify power management, then the device complexity is reduced, but the luminance compensation is inadequate
Solution Approach 1:
The patent segments the power supply system into two distinct voltage sources: a first power supply voltage (ELVDD) connected to the anode of light emitting elements, and a second power supply voltage (ELVSS) connected to the cathode. This segmentation allows independent control of each voltage level, enabling effective luminance compensation through adjustment of ELVSS based on degradation data while keeping ELVDD fixed, thus achieving reliable compensation without excessive complexity.
3Use of energy by moving object
If the first power supply voltage is decreased to reduce power consumption, then the power consumption is reduced, but the luminance of the display panel is also reduced
Solution Approach 1:
The patent maintains the first power supply voltage (ELVDD) at a fixed, optimal level to ensure sufficient luminance output. Instead of decreasing ELVDD to save power, the system compensates for degradation by dynamically adjusting the second power supply voltage (ELVSS) downward based on degradation data. This parameter change strategy ensures that power consumption is reduced through ELVSS adjustment without compromising luminance, as ELVDD remains constant and adequate.
Data Source
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AI summary
A display device including: a display panel including a plurality of pixels; and a panel driver connected to the display panel, the panel driver configured to generate stress data representing a degradation amount of the display panel, to generate corrected image data by adjusting input image data based on the stress data, to determine a luminance of the display panel based on a display brightness value or the corrected image data, to adjust a second power supply voltage based on the stress data and the luminance of the display panel, and to drive the display panel based on the corrected image data, a first power supply voltage and the second power supply voltage.