LCD Backlight Color Accuracy via Signal Correction
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Solution Overview
Problem
Existing liquid crystal display (LCD) devices struggle to accurately display certain colors, particularly red, due to light leakage from green and blue light sources when trying to display colors like white and red, leading to an undesired whitish tint instead of the intended color.
Innovation Solution
The implementation of a system with a backlight having multiple light sources of different peak wavelengths, where the emission intensities of these light sources are independently controllable, allowing for precise adjustment to minimize display errors in brightness and color by calculating and correcting the video signal based on the expected color information after passing through the liquid crystal panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the intensity of the red light source is set to maximum to display red color, then the red color can be displayed, but green and blue light sources leak and cause a whitish tint
Solution Approach 1:
The patent applies preliminary anti-action by pre-calculating and applying correction values to the signal values of green and blue light sources before they are transmitted to the liquid crystal panel. These correction values are specifically designed to counteract the light leakage effect, so that when the red light source is activated at maximum intensity, the unwanted green and blue leakage is compensated for in advance, preventing the whitish tint from occurring.
Solution Approach 2:
The patent implements feedback by measuring the actual color output of the liquid crystal display and comparing it with the intended color from the video signal. Based on this comparison, correction values are calculated and applied to adjust the signal values sent to the liquid crystal panel, creating a closed-loop system that continuously optimizes color accuracy to compensate for light leakage effects.
2Measurement precision
If all light source intensities are set to maximum to display white color, then white can be accurately displayed, but power consumption increases
Solution Approach 1:
The patent applies partial action by selectively activating only the necessary light sources at appropriate intensities rather than maximizing all light sources. When displaying white color, instead of setting all red, green, and blue light sources to maximum intensity, the system uses corrected signal values that optimize the contribution of each light source, reducing unnecessary energy consumption while maintaining color accuracy.
Solution Approach 2:
The patent changes the parameter of light source intensity by dynamically adjusting the intensity levels of individual light sources based on the required color output. The system calculates optimal intensity values for each light source rather than using fixed maximum values, enabling efficient power consumption while maintaining accurate color reproduction through precise parameter control.
3Device complexity
If the number of light sources is limited to three colors, then the device complexity is reduced, but the color reproduction gamut is limited
Solution Approach 1:
The patent applies universality by enabling three light sources (red, green, and blue) to perform multiple functions through independent intensity control and signal correction. Each light source can be selectively activated at different intensities to reproduce a wide range of colors, allowing the same three light sources to cover a broader color gamut than traditionally possible, thus achieving multi-functionality without increasing the number of physical light sources.
Data Source
AI summary
According to one embodiment, an image display device has a liquid crystal panel, a backlight, an intensity setting unit, a presumption unit, a signal correction unit, an error calculation unit and a control unit. The intensity setting unit sets intensities of the light sources, respectively. The presumption unit presumes color information based on intensity information representing the intensities. The signal correction unit corrects an input video signal according to the color information, and obtains a corrected video signal. The error calculation unit presumes a display image from the corrected video signal and the input video signal, and calculates display errors between the presumed display image and an input image corresponding to the input video signal. The control unit controls sets the intensities of the light sources as the emission intensities of the backlight so that the display errors obtained from the error calculation unit can be minimum.