Light Source Unit Green Phosphor Segmentation Color Purity
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Solution Overview
Problem
Existing liquid crystal displays using color conversion systems face challenges in achieving both higher brightness and enhanced color reproducibility due to a wider full width at half maximum in the light emission wavelength of green phosphors, which affects the color purity of blue, green, and red emissions.
Innovation Solution
A light source unit comprising a light emitting body with a green phosphor and a color conversion film using an organic luminescent material with a light emission wavelength peak between 580 nm and 750 nm, along with a laminated film and a polyester resin, to convert incident light into longer wavelengths, enhancing color purity and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a green phosphor with wider emission spectrum is used, then brightness is improved, but color purity deteriorates
Solution Approach 1:
The invention divides the green emission into two separate phosphors: a first green phosphor (520-560nm) for brightness and a second green phosphor (500-520nm or 560-580nm) for color purity. This segmentation allows each phosphor to specialize in one function, resolving the contradiction between brightness and color purity that plagues single-phosphor systems.
Solution Approach 2:
The invention uses a composite phosphor system combining multiple green phosphors with different emission characteristics. By复合 materials with complementary emission spectra, the system achieves both high brightness (from the main green phosphor) and high color purity (from the auxiliary green phosphor filling spectral gaps), eliminating the need to choose between the two opposing requirements.
2Illumination intensity
If the full width at half maximum of green phosphor emission is widened, then brightness is enhanced, but color reproducibility deteriorates
Solution Approach 1:
The green emission spectrum is segmented into multiple phosphors with different FWHM characteristics. The first green phosphor provides broad emission for brightness, while the second green phosphor provides narrow emission for color precision. This segmentation resolves the contradiction between brightness enhancement and color reproducibility maintenance.
Solution Approach 2:
Different regions of the green spectrum are assigned different qualities: the first green phosphor dominates the 520-560nm region for brightness, while the second green phosphor operates in adjacent regions (500-520nm or 560-580nm) for color accuracy. This local quality differentiation allows simultaneous optimization of brightness and color reproducibility across different spectral 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
The solution achieves both higher brightness and enhanced color reproducibility by narrowing the full width at half maximum of the green phosphor's emission spectrum, improving the color purity and gamut of displays and lighting devices.
Implementation Method 1
Color conversion means conversion of light emitted from a light-emitting body into light having a longer wavelength
Implementation Method 2
a color conversion film including an organic luminescent material configured to convert at least a part of incident light incident from the light emitting body into light having a wavelength longer than a wavelength of the incident light
Implementation Method 3
a layer including a green phosphor and formed on the light source
Data Source
AI summary
A light source unit includes: a light emitting body; and a color conversion film including an organic luminescent material configured to convert at least a part of incident light incident from the light emitting body into light having a wavelength longer than a wavelength of the incident light. The light emitting body includes a light source, and a layer including a green phosphor and formed on the light source. The organic luminescent material has a light emission wavelength peak in a wavelength region of 580 nm or longer and 750 nm or shorter.