LCD Backlight Spectrum and Color Filter Chromaticity Optimization
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Solution Overview
Problem
Conventional LCDs face challenges in improving color saturation while maintaining appropriate white point color temperature representation, as adjustments to enhance color saturation often result in color temperature shifts or sacrifice color saturation.
Innovation Solution
The LCD incorporates a backlight module with specific normalized emission spectrum peaks and a liquid crystal display panel with color filter layers that satisfy certain chromaticity coordinate relations, allowing for controlled color representation by balancing color saturation and white point color temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the green fluorescent powder intensity peak is changed from 540-550 nm to 510-520 nm to improve color saturation, then color saturation is improved, but white point color temperature shifts and color representation becomes distorted
Solution Approach 1:
The patent applies parameter changes by precisely controlling the intensity peak wavelengths of fluorescent powders (green: 510-520 nm, blue: 445-465 nm) and adjusting their luminance ratios (BL1/BL2 between 0.65-0.99) to achieve both high color saturation and accurate white point color temperature representation simultaneously
Solution Approach 2:
The patent applies local quality by optimizing specific regions of the emission spectrum - enhancing the cyan region (500-520 nm) and blue region (445-465 nm) with specific fluorescent powder characteristics while maintaining overall color balance, thereby achieving localized spectral improvements that translate to both saturation and accuracy
2Reliability
If the ratio of red, green, and blue fluorescent powders is adjusted to improve white point color temperature, then white point color temperature is improved, but color saturation is sacrificed
Solution Approach 1:
The patent simultaneously optimizes multiple parameters: the luminance ratio BL1/BL2 between 0.65-0.99, the green fluorescent powder peak at 510-520 nm, the blue fluorescent powder peak at 445-465 nm, and the chromaticity coordinates (Rx≥0.655, Gx≥0.275, By≥0.075), achieving both accurate white point color temperature and high color saturation
3Device complexity
If conventional fluorescent powder configurations are used to maintain simple backlight module design, then device complexity is low, but color saturation reaches only 70-75% NTSC ratio
Solution Approach 1:
The patent achieves high color saturation (92-95% NTSC) by optimizing fluorescent powder emission characteristics - specifically positioning the green peak at 510-520 nm and blue peak at 445-465 nm, with controlled luminance ratios, thereby improving color performance without adding complex structural elements to the backlight module
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 enables the LCD to maintain optimal white point color temperature while achieving high color saturation, with NTSC ratios ranging from 92% to 95%, suitable for various applications such as desktop screens and televisions.
Implementation Method 1
one of the substrates has a red filter layer, a green filter layer, and a blue filter layer, and the red filter layer, the green filter layer, and the blue filter layer satisfy the following relation expressions
Implementation Method 2
The backlight module has at least one white light source
Implementation Method 3
BL1 and BL2 respectively represent maximum brightness peaks of a normalized emission spectrum of the backlight module
Data Source
AI summary
A liquid crystal display (LCD) including a backlight module and a liquid crystal display panel is provided. The backlight module has at least one white light source. BL1 and BL2 respectively represent maximum brightness peaks of a normalized emission spectrum of the backlight module at a wavelength between 500 nm to 520 nm and between 445 nm to 465 nm, in which 0.91≦BL1/BL2≦0.99. The liquid crystal display panel is disposed above the backlight module, and has a plurality of substrates and one liquid crystal layer located between them. One of substrates has a red filter layer, a green filter layer, and a blue filter layer, and the coordinate values of the red filter layer, the green filter layer, and the blue filter layer in CIE 1931 chromaticity diagram satisfy predetermined relation expressions.