Multi-Color LED Backlighting for LCD Contrast and Color Gamut
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Solution Overview
Problem
LCD displays face limitations in contrast ratios, color gamut, and image quality due to the use of limited spectrum white light backlights, leading to unnatural color representation and blooming effects, which are not adequately addressed by existing local dimming technologies.
Innovation Solution
The implementation of a backlighting panel with an array of solid state lighting devices of differing colors, arranged into multiple zones, and a color management unit to generate signals for controlling chromaticity and luminance, with a ratio of solid state lighting devices to pixels greater than 1, enhancing contrast and color accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If white LED lamps with blue-emitting LED and yellow phosphor are used for backlighting, then the backlighting panel can be manufactured with simple structure, but the color gamut is limited and objects appear with unnatural coloring
Solution Approach 1:
The backlighting panel is segmented into multiple independent light emitting regions, each containing LEDs of different colors (red, green, blue, yellow, cyan, magenta). This segmentation allows each region to emit specific wavelengths independently, expanding the overall color gamut while maintaining manufacturing feasibility through modular assembly
Solution Approach 2:
The patent employs composite lighting structures combining multiple LED types (inorganic LEDs with different phosphor coatings) within a single backlighting panel. This composite approach integrates diverse light emission characteristics to achieve broader color coverage while preserving structural manufacturability
2Illumination intensity
If local dimming technology is implemented to improve contrast ratio, then contrast ratio is enhanced, but blooming effects persist and structural complexity increases
Solution Approach 1:
The backlighting panel is divided into numerous independently controllable light emitting regions (e.g., 1000+ zones), enabling precise local dimming control. Each region can be independently adjusted to match the luminance requirements of corresponding display areas, achieving high contrast ratios while minimizing blooming effects through fine-grained control
Solution Approach 2:
Different regions of the backlighting panel are assigned different luminance characteristics tailored to local display requirements. This local quality approach allows bright regions to emit higher intensity while dark regions emit lower intensity, optimizing contrast ratio locally without requiring complex global control mechanisms
3Ease of manufacture
If white light sources are used in LCD backlights, then the manufacturing process is simplified, but the chromaticity differentiation and image depth are limited
Solution Approach 1:
The uniform white backlight is segmented into multiple color-specific light emitting regions distributed across the panel. This segmentation enables precise chromaticity control for different display areas, improving color accuracy and differentiation while maintaining relatively simple manufacturing through standardized multi-color LED module integration
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
This solution significantly improves contrast ratios, reduces blooming effects, and expands the color gamut, enabling more natural and detailed image output by allowing for precise control of chromaticity and luminance across the display.
Implementation Method 1
a solid state light emitting device generates light through the recombination of electronic carriers, i.e. electrons and holes, in a light emitting layer or region
Implementation Method 2
white LED lamps that include a blue-emitting LED coated with a wavelength conversion phosphor that converts some of the blue light emitted by the LED into yellow light
Data Source
AI summary
Backlighting panels for LCD displays are described herein which, in some embodiments, enhance contrast ratio, spatial resolution and/or chromaticity differentiation in images output by the LCD displays. In one aspect, an electronic display device comprises a LCD panel comprising pixels, and a backlighting panel comprising an array of solid state lighting devices of differing color. A color management unit is configured to generate color management signals for controlling chromaticity and/or luminance output of the solid state lighting devices, wherein a ratio of the solid state lighting devices to the pixels of the LCD panel is greater than 1.