OLED Display Gamma Voltage Compensation for Luminance Uniformity
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Solution Overview
Problem
OLED displays experience luminance deviations between internal areas due to voltage drops in power lines, which existing compensation methods fail to fully address, particularly at varying gray and luminance levels, leading to color imbalances.
Innovation Solution
An OLED display system that dynamically adjusts the gamma reference voltage based on detected voltage levels and luminance or gray levels, using a power supply unit, gamma reference voltage generator, and data driver to output compensation gamma reference voltages, ensuring uniform luminance across the panel by calculating and applying voltage differences through lookup tables and compensation units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power voltage is transmitted through power lines to the display panel, then the display panel receives sufficient power for operation, but voltage drops occur causing luminance deviations between internal areas
Solution Approach 1:
The patent implements a feedback mechanism by detecting the actual voltage level at the display panel through a detection unit, calculating the voltage difference from a reference voltage, and using this information to dynamically adjust the gamma reference voltage. This closed-loop feedback system compensates for voltage drops in real-time, maintaining luminance uniformity across different display areas despite power transmission losses.
Solution Approach 2:
The patent changes the gamma reference voltage parameter dynamically based on detected voltage levels. The gamma reference voltage generator adjusts the voltage level according to the calculated voltage difference, thereby compensating for power line resistance effects. This parameter adjustment ensures that the display panel receives appropriate voltage levels to maintain consistent luminance characteristics across all display areas.
2Reliability
If existing compensation methods are used, then some voltage drop compensation is achieved, but luminance deviations persist particularly at varying gray and luminance levels
Solution Approach 1:
The patent transitions from static compensation methods to dynamic adjustment. The gamma reference voltage is continuously adjusted based on real-time detection of voltage levels and calculation of voltage differences. This dynamic approach adapts to varying display conditions including different gray levels and luminance levels, effectively eliminating persistent luminance deviations that static methods cannot address.
Solution Approach 2:
The patent employs feedback by detecting actual voltage levels at the display panel, calculating deviations from reference values, and using this information to adjust the gamma reference voltage. This feedback loop enables the system to compensate for voltage drops under varying operating conditions, improving luminance uniformity across different gray and luminance levels where existing methods fail.
3Manufacturing precision
If gamma reference voltage is adjusted dynamically, then luminance uniformity is improved, but system complexity increases with additional detection and control units
Solution Approach 1:
The patent integrates multiple functions into existing system components. The detection unit utilizes existing power line infrastructure for voltage detection, the gamma reference voltage generator works within the existing gamma voltage generation architecture, and the compensation mechanism leverages existing control pathways. This multi-functional integration achieves luminance uniformity improvement without requiring completely separate compensation hardware systems.
Solution Approach 2:
The patent introduces a gamma reference voltage generator as an intermediary component that bridges the power supply and the display panel. This intermediary adjusts the gamma reference voltage based on detected voltage differences, effectively mediating the compensation process. By using this intermediary approach, the system achieves complex compensation functionality while maintaining compatibility with existing display panel architecture and control mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively reduces luminance deviations between areas of the display panel, maintaining uniformity and optimal gamma voltage levels, thereby improving image quality by compensating for voltage drops and adjusting voltage levels according to changes in luminance and gray levels.
Implementation Method 1
OLED displays generate an emission current proportional to a voltage difference between a power voltage (e.g., a high power voltage ELVDD) applied to a display panel and a data signal
Data Source
AI summary
An OLED display is disclosed. The display includes a display panel having a luminance level of the display panel, a power supply unit providing first and second power voltages to the display panel, and a gamma reference voltage generator configured to i) generate a compensation gamma reference voltage, ii) detect a voltage level of the first power voltage at a detection point of the display panel, ii) change the compensation gamma reference voltage from a first voltage level to a second voltage level within a frame based at least in part on the detected voltage level, and iv) determine the first voltage level of the compensation gamma reference voltage based at least in part on the luminance level.