Display Grayscale Correction for Lateral Current Leakage
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Solution Overview
Problem
Organic light emitting display devices face issues with luminance inconsistency when emitting mixed or single color lights due to lateral leakage of driving current through shared P-doped Hole Injection Layers, leading to undesired luminance levels.
Innovation Solution
A display device with a grayscale corrector that adjusts input grayscale values based on observation target pixels, using light emitting pixel counters and converters to generate corrected grayscale values, incorporating single and mixed color offset providers to ensure accurate luminance for different color combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If grayscale voltages are set according to a gamma curve for white color light, then luminance accuracy for white light is improved, but luminance accuracy for single color light or mixed color light deteriorates
Solution Approach 1:
The patent applies dynamics by making the grayscale voltage adjustment adaptive based on the detected color type. The system dynamically switches between different correction methods: gamma curve correction for white light, single color offset correction for single color light, and mixed color offset correction for mixed color light. This allows the luminance accuracy to be maintained across different color types by changing the correction strategy based on real-time detection of the emitted light color.
Solution Approach 2:
The patent changes the parameter of grayscale voltage according to the detected color type. For white color light, the system uses gamma curve-based grayscale voltages. For single color light, it applies single color offset values to adjust the grayscale voltage. For mixed color light, it uses mixed color offset values. This parameter change ensures that the luminance accurately corresponds to the gamma curve regardless of whether the emitted light is white, single color, or mixed color.
2Device complexity
If a shared P-doped Hole Injection Layer is used for multiple pixels, then device structure is simplified, but lateral leakage of driving current occurs causing luminance inconsistency
Solution Approach 1:
The patent applies feedback by detecting the actual color of light emitted from each pixel and using this information to adjust the grayscale voltage. The detection unit determines whether the emitted light is white color light, single color light, or mixed color light, and then the correction unit adjusts the grayscale voltage accordingly. This feedback mechanism compensates for the lateral leakage effect in the shared P-doped Hole Injection Layer, ensuring luminance consistency without requiring structural changes.
Solution Approach 2:
The patent changes the parameter of grayscale voltage to compensate for lateral leakage. By detecting the color type and applying appropriate offset values or gamma curve corrections, the system adjusts the driving current parameters to maintain consistent luminance across different pixels that share the same P-doped Hole Injection Layer, thereby overcoming the leakage-induced inconsistency.
3Measurement precision
If grayscale voltages are adjusted for single color light emission, then luminance accuracy for single color light is improved, but luminance accuracy for white color light may deteriorate
Solution Approach 1:
The patent applies dynamics by implementing a adaptive correction system that detects the emitted light color and dynamically applies the appropriate correction method. When white color light is detected, the system uses gamma curve correction. When single color light is detected, it applies single color offset correction. When mixed color light is detected, it uses mixed color offset correction. This dynamic adaptation ensures that luminance accuracy is maintained for all color types without compromising any single color's performance.
Solution Approach 2:
The patent changes the grayscale voltage parameters based on the detected color type. The correction unit modifies the grayscale voltage by adding appropriate offset values or applying gamma curve transformations depending on whether the emitted light is white, single color, or mixed color. This parameter change strategy ensures that each color type receives the optimal correction to maintain accurate luminance correspondence to the gamma curve.
Data Source
AI summary
A display device includes: a target pixel; observation target pixels located adjacent to the target pixel; and a grayscale corrector for converting an input grayscale value corresponding to the target pixel with reference to observation target grayscale values corresponding to the observation target pixels. The grayscale corrector includes: a light emitting pixel counter for providing a number of light emitting pixels by counting a number of observation target pixels that exceeds a reference value; and a grayscale converter for providing a converted grayscale value by converting the input grayscale value, based on the number of light emitting pixels.