Display Luminance Compensation for Leakage-Induced Color Drift
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Solution Overview
Problem
Display devices exhibit luminance and color coordinate deviations due to leakage characteristics, leading to inconsistent luminance when displaying white and mixed colors, which are not accurately represented by the sum of individual color luminances.
Innovation Solution
A luminance compensation method that measures actual and target luminance values, calculates compensation amounts, and adjusts input image data to correct for these deviations by using a compensation lookup table.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the display device displays white color by mixing red, green, and blue colors, then the white color luminance should equal the sum of individual color luminances, but the actual white luminance differs from the sum due to leakage characteristics
Solution Approach 1:
The patent measures the luminance of individual color subpixels (red, green, blue) and the white color at multiple grayscale levels before operation, and pre-calculates compensation values stored in a lookup table. This preliminary measurement and calculation approach allows the display device to compensate for leakage characteristics without real-time computation, ensuring accurate white luminance representation.
Solution Approach 2:
The patent changes the voltage parameters applied to subpixels by applying compensation voltages derived from measured luminance data. By adjusting the voltage codes for red, green, and blue subpixels individually based on their specific leakage characteristics, the system achieves accurate white luminance mixing while accounting for color-specific leakage variations at different grayscale levels.
2Manufacturing precision
If the display device uses the same voltage for red, green, and blue subpixels to display white, then the color coordinates should be accurate, but leakage characteristics cause color coordinates to vary with grayscale values
Solution Approach 1:
The patent segments the white color control into separate red, green, and blue subpixel controls with individual compensation values. Instead of applying a single voltage to all subpixels, the system calculates and applies separate compensation voltages to each color channel based on their specific leakage characteristics, thereby maintaining accurate color coordinates across different grayscale levels.
Solution Approach 2:
The patent implements a feedback mechanism where luminance measurements of individual color subpixels and white color are used to generate compensation values. The measured luminance data feeds into the compensation calculation, which then adjusts the voltage codes for subsequent display operations, creating a closed-loop system that corrects for leakage-induced color coordinate variations.
3Measurement precision
If the display device measures luminance for all grayscale values of all colors, then complete compensation data can be obtained, but the measurement and processing time increases significantly
Solution Approach 1:
The patent performs comprehensive luminance measurements for all grayscale values of red, green, blue, and white colors during the initialization or calibration phase before normal operation. These measurements are stored in a lookup table, allowing the display device to retrieve pre-calculated compensation values during actual display operations without performing time-consuming measurements and calculations in real-time.
Data Source
AI summary
A luminance compensation method for a display device includes measuring a luminance of each of white grayscale values, measuring an actual luminance value for each of colors, determining a target luminance value for each of the colors based on the luminance of each of the white grayscale values and a luminance contribution ratio of each of the colors, determining a luminance compensation amount for each of the colors based on the target luminance value and the actual luminance value, and compensating for input image data for each of the colors based on the luminance compensation amount.