Red Color Filter Pigment Absorption for Display Gamut
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Solution Overview
Problem
Existing color filters for displays, particularly those used with broadband OLED devices, fail to provide improved color rendition and gamut, often resulting in compromised color reproduction compared to standards like NTSC and HDTV references, and may not be suitable for both CCFL and OLED light sources due to differences in spectral intensity.
Innovation Solution
A red color filter with a pigment having maximum absorption between 450 to 575 nm, achieving chromaticity coordinates of 0.665≦x≦0.68 and 0.30≦y≦0.34 in the 1931 CIE XYZ colorimetric system, which enhances color gamut and spectral curve shape without the need for auxiliary yellow colorants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional color filters are used with broadband OLED devices, then the display can be manufactured, but the color rendition and gamut are compromised and fail to meet NTSC and HDTV standards
Solution Approach 1:
The patent applies parameter changes by precisely controlling the maximum absorption wavelength of the pigment (450-575 nm range) and optimizing the chromaticity coordinates (x: 0.665-0.68, y: 0.30-0.34) to achieve superior color reproduction that meets NTSC and HDTV standards while maintaining compatibility with broadband OLED emission spectra
Solution Approach 2:
The patent uses composite materials by combining the red pigment with specific carriers and dispersants to create a color filter layer that achieves both the required optical properties for pure red color and the manufacturing feasibility for integration with OLED devices
2Adaptability or versatility
If color filters are designed for CCFL light sources, then they work with fluorescent displays, but they are not suitable for OLED displays due to differences in spectral intensity
Solution Approach 1:
The patent achieves universality by designing a color filter with a broad absorption band (450-575 nm) that can effectively absorb both the spectral peaks of CCFL sources and the broader emission spectrum of OLED devices, making the same filter suitable for multiple light source types
Solution Approach 2:
The patent applies local quality by optimizing the absorption characteristics in specific wavelength regions (enhancing absorption at OLED emission peaks while maintaining appropriate transmission in the red region) to achieve spectral matching accuracy for OLED while retaining compatibility with CCFL sources
3Ease of manufacture
If the red filter allows transmission tail into green region, then it provides adequate color with CCFL sources, but it results in impure red color and compromised color gamut
Solution Approach 1:
The patent uses parameter changes by optimizing the absorption band shape and position (maximum absorption at 450-575 nm) to achieve a balance where the filter maintains simplicity in design while achieving superior color purity with chromaticity coordinates of x: 0.665-0.68 and y: 0.30-0.34, eliminating the need for transmission tails into the green region
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 solution provides improved color rendition and gamut with reduced efficiency loss, achieving purer red, green, and blue colors, and is suitable for both CCFL and OLED displays, meeting or exceeding NTSC and HDTV color standards.
Implementation Method 1
a pigment having a maximum absorption at a wavelength within the range of from 450 to 575 nm
Data Source
AI summary
A red color filter having a red filter layer comprising a pigment having a maximum absorption at a wavelength within the range of from 450 to 575 nm, wherein the red filter layer has chromaticity coordinates (x, y) in the 1931 CIE XYZ calorimetric system, calculated using CIE Standard illuminant D65, that satisfy the expressions 0.665≦x≦0.68 and 0.30≦y≦0.34.