Display Color Compensation Matrix for Uniform Chromaticity and Brightness
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Solution Overview
Problem
LED and OLED displays face challenges in achieving uniform chromaticity and brightness across sub-pixels due to differences in color and brightness, leading to non-uniform display images.
Innovation Solution
A method involving a control circuit with a processor and memory unit that generates control signals for sub-pixels to emit light in a virtual color gamut, using a compensation matrix to adjust brightness and avoid overlapping color areas on a chromaticity plane, ensuring consistent chromaticity and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional OLED displays use drive transistors to control pixel brightness, then power consumption is reduced and manufacturing flexibility is improved, but non-uniform chromaticity and brightness occur across sub-pixels
Solution Approach 1:
The patent applies parameter changes by transforming the non-linear relationship between drive current and perceived brightness into a linear relationship through gamma correction. The system adjusts the exponent parameter in the power function to match human visual perception characteristics, ensuring uniform chromaticity and brightness across different sub-pixels while maintaining the power-efficient OLED architecture.
Solution Approach 2:
The patent implements feedback through a look-up table (LUT) that stores pre-calibrated gamma correction values. The control circuit queries the LUT to retrieve appropriate drive current values based on desired brightness levels, creating a feedback mechanism that compensates for the non-linear response of OLED sub-pixels and ensures uniform display output across all color channels.
2Illumination intensity
If drive current is increased to improve pixel brightness, then luminance is enhanced, but non-linear brightness variations and chromaticity inconsistencies occur
Solution Approach 1:
The patent changes the functional parameter relationship by applying gamma correction with a specific exponent value that linearizes the brightness response. This transforms the non-linear power function relationship between drive current and luminance into a linear relationship, ensuring that equal steps in drive current produce equal perceived brightness steps across all sub-pixels.
Solution Approach 2:
The patent introduces an additional dimension of control by separating the brightness control into two independent stages: gamma correction for linearizing the brightness response, and then standard PWM or current control for achieving desired luminance levels. This dimensional separation allows independent optimization of brightness uniformity and intensity.
3Manufacturing precision
If gamma correction is applied to linearize brightness response, then brightness uniformity is improved, but device complexity increases due to additional control circuits
Solution Approach 1:
The patent uses a look-up table (LUT) to store pre-calculated gamma correction values, effectively copying the complex gamma correction function into a simple memory structure. This allows the control circuit to retrieve corrected drive current values through simple memory access operations rather than performing complex real-time calculations, significantly reducing the computational complexity of the control circuit.
Solution Approach 2:
The patent performs gamma correction calculations in advance during the display calibration process and stores the results in a look-up table. This preliminary action eliminates the need for complex real-time gamma correction computations during normal display operation, reducing the complexity of the runtime control circuit while maintaining brightness uniformity.
Data Source
AI summary
Embodiments of the present disclosure relate to an electronic device. The electronic device comprises a display comprising an array of pixels and a control circuit electrically connected to the display. Pixels of the array of pixels includes a plurality of first sub-pixels defining a first color area on a chromaticity plane, a plurality of second sub-pixels defining a second color area on the chromaticity plane, and a plurality of third sub-pixels defining a third color area on the chromaticity plane. The control circuit comprises a processor and a memory unit. The processor configured to receive an input image signal; based on the input image signal and a compensation matrix, generate a control signal for controlling a pixel of the display to emit light in a virtual color gamut, which is among the first, second, and third color areas does not overlap any of the first, second, or third color areas on the chromaticity plane, wherein the compensation matrix is determined according to the first, second, and third color areas; perform brightness adjustment on the control signal to generate a pixel driving signal for driving the pixel of the display; and output the pixel driving signal to the display for driving each pixel of the display to output light.