LCD Backlight Dimming Control for Blended Color Prevention
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Solution Overview
Problem
LCD devices face issues with blended colors due to the mixing of chromatic and non-chromatic color domains within blocks, particularly when using white, red, green, and blue LEDs in the backlight unit, leading to deteriorated hues and limited block definitions.
Innovation Solution
An LCD device with a liquid crystal display panel, a backlight unit using light emission diode arrays, and a dimming signal generation system that divides image data into block data, calculates grayscale differences, and selects dimming signals to minimize blended colors by controlling the backlight's brightness and color dimming modes based on histogram analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the backlight unit uses white, red, green, and blue LEDs to provide sufficient brightness and low power consumption, then the illumination intensity and energy efficiency are improved, but blended colors appear at block boundaries due to mixing of chromatic and non-chromatic color domains
Solution Approach 1:
The patent divides the backlight unit into multiple independent LED blocks corresponding to screen blocks, with each block containing specific color combinations (white, red, green, blue LEDs). This segmentation allows independent control of chromatic and non-chromatic domains, preventing color mixing at boundaries while maintaining sufficient overall brightness and energy efficiency.
2Device complexity
If the number of blocks on the LCD panel is limited, then the device complexity is reduced, but chromatic and non-chromatic color domains mix within specific blocks causing blended colors
Solution Approach 1:
The patent applies different LED color compositions to different block regions. Specific blocks contain only white LEDs (non-chromatic domain) while other blocks contain red, green, and blue LEDs (chromatic domain). This local differentiation prevents color mixing within blocks while maintaining a limited overall block structure.
3Ease of manufacture
If the LCD device uses a limited number of LED blocks, then the manufacturing cost is reduced, but the ability to independently control chromatic and non-chromatic domains is compromised
Solution Approach 1:
The patent designs LED blocks with universal structures that can contain different LED types (white, red, green, blue) based on required functionality. Each block maintains the same basic structure and control interface, allowing independent chromatic/non-chromatic domain control while using standardized manufacturing processes and components.
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
The solution effectively prevents blended colors by optimizing the backlight's operation, ensuring clear and accurate color representation within each block, enhancing the overall image quality and reducing power consumption.
Implementation Method 1
a backlight unit configured to irradiate light on the liquid crystal display panel using a plurality of light emission diode arrays each with a plurality of light emission diodes
Data Source
AI summary
An LCD device and a driving method thereof are discussed. The LCD device can prevent a blended color within each block which is defined in an LCD panel. To this end, the LCD device divides an external image data into a plurality of block image data, generates first dimming signals opposite to red, green, and blue data with each block image data, and provides a second dimming signal opposite to a brightness data with each block image data. Also, the LCD device calculates a difference value between maximum and minimum grayscale values by analyzing histograms for the red, green, and compares the calculated difference value with a reference difference value. Furthermore, the LCD device allows one of the first and second dimming signals to be selected according to the dimming mode control signal.