Cut Filter Backlight Module for LCD Color Gamut
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Solution Overview
Problem
Conventional backlight modules, particularly those using CCFL and LED light sources, fail to achieve optimal color gamut and full color expression due to limitations in fluorescent materials and techniques, leading to insufficient color saturation in display devices.
Innovation Solution
A backlight module with a cut filter positioned over a light source emitting red, green, and blue light to filter off overlapping wavelengths, enhancing color purity and gamut by isolating primary colors, thereby improving color reproduction in liquid crystal display devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional LED with color filter is used in backlight module, then color gamut range is relatively large, but color purity is reduced due to overlapping wavelengths
Solution Approach 1:
The patent segments the broad LED spectrum into distinct wavelength bands using multiple cut filters. Each cut filter removes specific overlapping wavelength ranges, separating the spectral components into purer red, green, and blue bands. This segmentation of the spectrum resolves the contradiction by maintaining the broad gamut coverage while eliminating the wavelength overlaps that reduce color purity.
Solution Approach 2:
The patent extracts and removes the harmful overlapping wavelength components from the LED spectrum using cut filters. By taking out the specific wavelength ranges that cause color contamination (e.g., removing green wavelengths from the blue channel and red wavelengths from the green channel), the solution preserves the overall gamut while extracting the impurities that reduce color purity.
2Device complexity
If CCFL is used as backlight light source, then device structure is simple, but color gamut is insufficient due to fluorescent material limitations
Solution Approach 1:
The patent changes the spectral parameters of the backlight by introducing cut filters that selectively remove specific wavelength bands. This transforms the broad, overlapping LED spectrum into three distinct, purer wavelength bands. The parameter change in spectral distribution achieves NTSC 120% color gamut while maintaining the simplicity of the LED backlight structure.
3Illumination intensity
If broad spectrum LED is used to achieve large color gamut, then color saturation is improved, but overlapping wavelengths reduce color purity
Solution Approach 1:
The patent introduces cut filters as intermediary elements between the broad spectrum LED and the color filter array. These intermediaries selectively block overlapping wavelength ranges, allowing the broad spectrum LED to maintain high color saturation while the cut filters ensure color purity by removing contaminating wavelengths before they reach the display panel.
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 implementation of a cut filter significantly enhances the color gamut of display devices, achieving nearly 120% of the NTSC TV color gamut, surpassing conventional LED-based systems by isolating purer primary colors and improving color saturation.
Implementation Method 1
The cut filter is positioned over the light source to filter off a part of the light comprising an overlap of at least two of the red light, the green light, and the blue light
Data Source
AI summary
A cut filter is used in a backlight module or a display device and positioned over the light source to filter off a part of the light comprising an overlap of at least two of the red light, the green light, and the blue light. By filtering off the overlapping part of light emitted from the light source to obtain a purer primary color light, the display device equipped with a conventional color filter can attain an improved color gamut.