RGBW Display Backlight Control via Saturation Mapping
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Solution Overview
Problem
RGBW display apparatuses face challenges in achieving luminance and chromaticity similar to conventional RGB display apparatuses due to the addition of a white sub-pixel, requiring complex and memory-intensive pre-mapping lookup tables to adjust color signals, which increases power consumption and degrades image quality.
Innovation Solution
A four-primary-color display apparatus with a four-color mapping unit, dynamic backlight control unit, and saturation mapping unit that generates mapping scale ratios and white color signal adjust ratios to produce four-color image signals, reducing the need for large memory volumes and improving image quality by dynamically adjusting backlight intensity and white color signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a pre-mapping lookup table is used to adjust color signals in RGBW display apparatus, then luminance and chromaticity can be improved, but memory volume requirements increase significantly
Solution Approach 1:
The patent divides the color signal adjustment process into two separate stages: first, a four-color mapping unit performs initial color space conversion from RGB to RGBW using a compact lookup table; second, a dynamic backlight control unit performs chromaticity adjustment based on saturation values. This segmentation allows each unit to use a smaller, more efficient lookup table rather than one large comprehensive table, thereby reducing overall memory requirements while maintaining luminance and chromaticity quality.
Solution Approach 2:
The patent changes the control parameter from direct color signal adjustment to saturation-based backlight control. By calculating saturation values and using them to dynamically adjust backlight intensity and white sub-pixel contribution, the system achieves chromaticity adjustment without requiring large memory tables, thus reducing memory volume while preserving display quality.
2Reliability
If complex pre-mapping lookup tables are used to adjust color signals, then display quality can be maintained, but power consumption increases
Solution Approach 1:
The patent segments the display control into two independent units with specialized functions: the four-color mapping unit handles basic color conversion with a small lookup table, while the dynamic backlight control unit handles chromaticity adjustment based on real-time saturation calculation. This segmentation reduces the computational burden and memory access requirements compared to a single complex mapping system, thereby reducing power consumption while maintaining display quality.
Solution Approach 2:
The system uses the image content itself (saturation values calculated from input signals) to control the backlight and white sub-pixel adjustment, eliminating the need for external complex mapping tables. The saturation-based control mechanism is self-adaptive and requires minimal memory resources, reducing power consumption while preserving chromaticity accuracy.
3Loss of energy
If the white sub-pixel is added to each pixel, then transmittance and power efficiency are improved, but luminance and chromaticity deteriorate when displaying pure color images
Solution Approach 1:
The patent implements dynamic control of the white sub-pixel contribution based on real-time saturation value calculation. The dynamic backlight control unit adjusts the white sub-pixel and backlight intensity according to the saturation of the input image content, allowing the system to optimize between power efficiency and chromaticity/luminance quality on a per-frame basis, rather than using a fixed white sub-pixel configuration.
Solution Approach 2:
The patent changes the control approach from fixed color signal mapping to dynamic saturation-based parameter adjustment. By calculating saturation values and using them to modulate the white sub-pixel and backlight intensity, the system can adaptively control the white sub-pixel's contribution, improving chromaticity and luminance for pure color images while maintaining power efficiency benefits for other content types.
Data Source
AI summary
In an exemplary RGBW display apparatus, a plurality of four-color image output signals and a plurality of mapping scale ratios are generated according to a plurality of three-color image input signals. Furthermore, a backlight output intensity outputted from a backlight module is dynamically adjusted according to the mapping scale ratios and a white color signal adjust ratio is generated. In addition, a white color signal in each of the four-color image output signals is adjusted to be an updated white color signal according to the white color signal adjust ratio.