Gray-Scale Voltage Generation for OLED Color Temperature Stability
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Solution Overview
Problem
Existing display devices, particularly organic electroluminescent displays, face challenges in natural dimming without altering the color temperature, as current methods often require changes in gray-scale voltage levels that can affect image quality.
Innovation Solution
A method and apparatus for generating gray-scale voltages in organic electroluminescent display devices using a gamma correction circuit and a reference voltage table, which adjusts luminance levels through multiple steps by searching and interpolating gamma circuit control signals to maintain consistent color temperature during dimming operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If gray-scale voltage levels are adjusted for dimming, then luminance level is improved, but color temperature changes
Solution Approach 1:
The patent changes multiple parameters simultaneously - adjusting not only the gray-scale voltage levels but also the reference voltages VGH and VGL, and the emission timing of sub-pixels. By coordinating these parameter changes, the system achieves luminance dimming while compensating for color temperature shifts, thereby maintaining consistent color appearance across different brightness levels.
2Illumination intensity
If gray-scale voltages are adjusted for dimming, then luminance level is improved, but image quality deteriorates
Solution Approach 1:
The patent implements dynamic adjustment of multiple voltage parameters (gray-scale voltages, reference voltages VGH and VGL) and emission timing based on the target luminance level. This dynamic coordination ensures that image quality is maintained across different dimming levels by adaptively optimizing the voltage and timing parameters for each luminance state, preventing degradation that would occur with static adjustment methods.
Solution Approach 2:
The patent changes multiple parameters simultaneously - adjusting not only the gray-scale voltage levels but also the reference voltages VGH and VGL, and the emission timing of sub-pixels. By coordinating these parameter changes, the system achieves luminance dimming while compensating for color temperature shifts, thereby maintaining consistent color appearance across different brightness levels.
3Stability of the object's composition
If multiple voltage parameters are adjusted for natural dimming, then color temperature stability is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple voltage control functions into an integrated control system that simultaneously manages gray-scale voltages, reference voltages VGH and VGL, and emission timing. By combining these control functions and coordinating their adjustments together, the system achieves color temperature stability during dimming while avoiding the need for separate, independent control mechanisms for each parameter.
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
Enables natural dimming in organic electroluminescent displays without changing the color temperature, ensuring image quality by precisely controlling gray-scale voltages based on pre-defined reference voltage levels for each luminance level.
Implementation Method 1
The gray-scale voltages are generated by using a gamma correction circuit or others
Implementation Method 2
OLEDs, which are self light-emitting devices
Data Source
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AI summary
An apparatus and method for performing natural luminance adjustment by adjusting voltage levels of gray-scale voltages of a display device through a plurality of steps and determining gray-scale voltage levels of intermediate luminance levels using predetermined data when a luminance level of the display device is adjusted.