Gamma Voltage Generator for OLED Luminance Uniformity
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Solution Overview
Problem
Organic light-emitting display devices face luminance non-uniformity due to voltage drops in the power supply voltage across the display panel caused by internal resistance, leading to reduced display quality.
Innovation Solution
The implementation of a gamma voltage generator that varies in synchronization with the vertical synchronization signal to compensate for voltage drops by adjusting data signals, ensuring consistent luminance across the panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional power supply voltage is provided to the display panel, then the display device can operate, but voltage drops occur due to internal resistance causing luminance non-uniformity
Solution Approach 1:
The patent applies dynamics by making the power supply voltage variable rather than fixed. The gamma voltage generator dynamically adjusts the power supply voltage in synchronization with the vertical synchronization signal, changing the voltage level based on the scan line position and frame timing. This dynamic adjustment compensates for voltage drops along different scan lines, ensuring uniform luminance across the display panel while maintaining a relatively simple power supply structure.
2Reliability
If the power supply voltage is increased to compensate for voltage drops, then luminance uniformity improves, but power consumption increases
Solution Approach 1:
The patent applies parameter changes by adjusting the power supply voltage according to specific conditions rather than using a constant high voltage. The gamma voltage generator changes the voltage parameter dynamically based on the vertical synchronization signal and scan line position. This allows the system to maintain adequate voltage for compensation only where needed, avoiding unnecessary power consumption while achieving luminance uniformity.
Solution Approach 2:
The dynamic adjustment of power supply voltage in synchronization with the vertical synchronization signal ensures that voltage compensation is applied only when and where necessary. This dynamic approach prevents continuous high power consumption while maintaining luminance uniformity, as the voltage is adjusted based on the actual display requirements and scan line positioning.
3Reliability
If gamma voltage is adjusted to compensate for voltage drops, then luminance uniformity improves, but device complexity increases
Solution Approach 1:
The patent introduces a gamma voltage generator as an intermediary component between the power supply and the display panel. This intermediary device generates the adjusted power supply voltage based on the vertical synchronization signal, effectively mediating the voltage compensation process. By using this intermediary, the main display circuitry remains relatively simple while the gamma voltage generator handles the complexity of voltage adjustment, achieving luminance uniformity without significantly increasing overall device complexity.
Solution Approach 2:
The gamma voltage generator operates periodically in synchronization with the vertical synchronization signal, adjusting the power supply voltage at regular intervals corresponding to frame boundaries and scan line positions. This periodic action simplifies the control mechanism compared to continuous adjustment, as the voltage changes are triggered by the existing timing signals already present in the display system, thereby limiting the increase in device complexity while maintaining effective compensation.
Data Source
AI summary
An organic light-emitting display device includes an organic light-emitting display panel displaying an image that includes a plurality of frames, a data driver providing a plurality of data signals, which correspond to the image, to the organic light-emitting display panel, and a gamma voltage generator providing a gamma voltage, which varies in a same period as each of the frames, to the data driver.