Notch Filter Backlight for LCD Color Saturation
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Solution Overview
Problem
Liquid Crystal Display (LCD) technology faces challenges in achieving high color saturation, particularly in comparison to OLED technology, as existing methods using color filters and LED light sources struggle to expand the color gamut beyond 90% NTSC, limiting the vividness of colors displayed.
Innovation Solution
A method and backlight module that utilize a notch filter with a cut-off central wavelength of 500-640 nanometers and a half peak width of 10-120 nanometers to filter light entering the liquid crystal cell, allowing for increased color saturation by adjusting the LED spectrum, specifically using RG or YAG LEDs in combination with the notch filter to enhance the NTSC area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional color filters and LED light sources are used to improve color saturation, then NTSC can reach 80-93%, but it is not possible to achieve ultra-wide color gamut of 100%
Solution Approach 1:
The patent changes the spectral parameters of the backlight by introducing a notch filter with specific cut-off wavelength (500-640nm) and half peak width (10-120nm). This parameter change in the light spectrum enables the color saturation to reach NTSC 100% by removing specific wavelength components that limit color gamut
Solution Approach 2:
The notch filter acts as an intermediary component between the LED light source and the liquid crystal cell. It mediates the spectrum by selectively blocking specific wavelength ranges, thereby enabling the system to achieve ultra-wide color gamut without requiring changes to the fundamental LED or color filter design
2Illumination intensity
If the thickness of the color filter is increased to reduce half peak widths of R, G, B spectra, then color saturation improves, but light transmission is reduced
Solution Approach 1:
Instead of using a thick color filter that blocks broad wavelength ranges, the patent extracts only the specific problematic wavelength components using a notch filter. This selective extraction maintains high light transmission while achieving the necessary spectral shaping for high color saturation
Solution Approach 2:
The notch filter applies local quality changes to the spectrum by targeting specific wavelength regions (500-640nm with 10-120nm half peak width) rather than uniformly filtering across the entire spectrum. This localized filtering approach preserves overall light transmission while improving color saturation in critical regions
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 significantly increases color saturation, potentially reaching NTSC 100% without requiring specific color filter designs, improving the LCD's ability to display a wider range of colors by optimizing the LED spectrum and filter placement within the backlight module.
Implementation Method 1
light of backlighting of the LCD device is subjected to light filtering by a notch filter
Implementation Method 2
The notch filter has a cut-off central wavelength of 500-640 nanometers. The cut-off wave band of the half peak width is 10-120 nanometers
Implementation Method 3
The backlight module uses an RG LED (Light-Emitting Diode) or a YAG LED
Implementation Method 4
an LED containing red and green fluorescent powder, an LED containing multiple color chips or using a quantum dot to serve as fluorescent powder
Data Source
AI summary
The present invention relates to a method and a backlight module that achieve high color saturation of an LCD device. The backlight module that achieves high color saturation of the LCD device includes a notch filter. Light of backlighting of the backlight module is subjected to light filtering by the notch filter and then enters a liquid crystal cell of the LCD device. The notch filter has a cut-off central wavelength of 500-640 nanometers. The half peak width of the cut-off wave band is 10-120 nanometers. The notch filter has a thickness of 0.3-15 millimeters. The present invention also provides a method for achieving high color saturation of an LCD device. The present invention proposes a novel high color saturation technique that allows the color saturation to be increased at different extents in different backlighting and that may have NTSC reach 100% when used with an RG LED.