Multi-primary LED Backlight for LCD Color Gamut and Efficiency
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Solution Overview
Problem
Conventional direct-view liquid crystal displays face issues such as motion artifacts, limited view angle performance, head-on contrast ratio, limited color gamut due to dye quality and lamp spectra, non-optimum power efficiency, and environmental concerns related to mercury in CCFL lamps, which hinder their competitiveness and functionality.
Innovation Solution
The implementation of a direct-view display system that operates in multiple modes, including 2D, enhanced color gamut, privacy screen, dual-image, and stereoscopic image modes, utilizing an optical structure with six primary spectral emitters and polarization interference filters for improved light recycling and spectral separation, along with LED backlights for enhanced brightness, efficiency, and color accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If CCFL lamps are used for backlight illumination, then broad spectrum coverage is achieved, but color gamut is limited due to lamp spectra and dye quality
Solution Approach 1:
The backlight system is segmented into multiple independent light sources with distinct spectral characteristics (blue LED, cyan LED, green LED, yellow-green LED, orange LED, red LED). Each LED emits a narrow spectral band, and by combining these segmented spectral components, the system achieves expanded color gamut while maintaining broad spectrum coverage.
Solution Approach 2:
The invention changes the spectral parameters of the backlight by transitioning from broad-spectrum CCFL lamps to narrow-spectrum LEDs with specifically selected peak wavelengths. This parameter change enables precise spectral control and expansion of the displayable color gamut beyond what is achievable with conventional CCFL-based systems.
2Illumination intensity
If CCFL lamps are used for backlight illumination, then sufficient brightness is achieved, but power efficiency is non-optimum
Solution Approach 1:
The invention changes the operational parameters of the backlight system by using LEDs that convert electrical energy to light more efficiently than CCFL lamps. The multi-LED configuration with optimized current driving achieves superior power efficiency while maintaining or enhancing brightness levels.
3Illumination intensity
If CCFL lamps are used for backlight illumination, then adequate illumination is provided, but environmental harm is caused due to mercury content
Solution Approach 1:
The invention extracts and eliminates the harmful mercury component from the backlight system by replacing CCFL lamps with mercury-free LED light sources. This extraction of the harmful substance is achieved while maintaining adequate illumination through the multi-LED configuration.
Solution Approach 2:
The invention converts the harmful mercury-based illumination system into a beneficial mercury-free LED system. By removing the harmful element and replacing it with environmentally friendly LEDs, the system achieves both adequate illumination and environmental sustainability.
4Illumination intensity
If six-primary spectral emitters are used, then color gamut is enhanced, but device complexity increases
Solution Approach 1:
The backlight system is divided into six independent LED light sources, each emitting a narrow spectral band. This segmentation allows for enhanced color gamut while managing complexity through modular design, where each LED can be independently controlled and optimized.
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 approach addresses performance deficiencies by reducing motion artifacts, improving color gamut, contrast, and power efficiency while eliminating mercury usage, providing a more competitive and environmentally friendly display solution with enhanced functionality.
Implementation Method 1
The optical structure may be used to produce a brighter backlight structure through light recycling of the wider bandwidth light back into the optical structure
Implementation Method 2
The optical structures may be spectrally distinct and may illuminate the same light guide plate. The optical structures may be driven in time-sequential fashion to illuminate the light guide plate in synchrony with left and right eye images sequentially driven to the liquid crystal display panel
Implementation Method 3
utilizing an optical structure with six primary spectral emitters and polarization interference filters for improved light recycling and spectral separation
Data Source
AI summary
A direct view display provides a light modulating panel and a backlight including first and second sets of spectral emitters. Several modes of operation may be provided including an advanced 2D mode, and an enhanced color gamut mode employing simultaneous illumination of the first and second set of spectral emitters. Another embodiment may be an optical structure for a multi-functional LCD display with wide color gamut and high stereo contrast. The optical structure may also be used to produce more saturated colors for a wider display color gamut and also may be used to produce a brighter backlight structure through light recycling of the wider bandwidth light back into the optical structure.