Phosphor Manufacturing for White Light Color Rendition
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Solution Overview
Problem
Conventional white light emitting devices using blue light emitting diodes and yellow phosphors suffer from quantum deficits and reduced optical efficiency, leading to insufficient green and red color components, resulting in unnatural color display and limited applications.
Innovation Solution
A phosphor manufacturing method using inorganic compounds of the aMO-bAl2O3-cSi3N4 three-component system, where M is selected from Mg, Ca, Sr, and Ba, to produce phosphors that emit green, yellow, and red light when excited by light in the 350-480 nm wavelength range, with specific ratios and thermal treatment conditions to achieve stable crystal structures and optimal color rendition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a blue light emitting diode and a yellow phosphor are combined to emit white light, then the device structure is simple and easy to manufacture, but the green and red color components are insufficient resulting in unnatural color display
Solution Approach 1:
The invention segments the yellow phosphor emission into multiple distinct color components by using multiple phosphors with different emission characteristics. Specifically, it combines a first phosphor emitting green light (520-560nm), a second phosphor emitting yellow light (560-580nm), and a third phosphor emitting red light (600-680nm), each with specific emission peaks and full width at half maximum values, to achieve comprehensive color coverage while maintaining manufacturing simplicity
Solution Approach 2:
The invention uses a composite phosphor system consisting of multiple phosphor materials with specific characteristics. The composite includes a first phosphor with green emission (peak 530-550nm, FWHM 80-120nm), a second phosphor with yellow emission (peak 570-590nm, FWHM 80-120nm), and a third phosphor with red emission (peak 620-650nm, FWHM 80-120nm), all excited by a blue light emitting diode (peak 440-470nm). This composite approach enables superior color rendering while maintaining ease of manufacture through a single phosphor layer structure
2Ease of operation
If a yellow phosphor is coated on a blue light emitting diode to mix blue and yellow light, then the device is easy to operate and low in price, but quantum deficits occur and optical efficiency is reduced
Solution Approach 1:
The invention applies local quality by assigning specific emission characteristics to different phosphor components within the phosphor layer. Each phosphor (green, yellow, red) has optimized emission peak wavelengths and FWHM values tailored to fill specific gaps in the spectrum, maximizing the utilization of the blue LED excitation source and minimizing quantum deficits while maintaining ease of operation
Solution Approach 2:
The composite phosphor system with three distinct phosphors (green, yellow, red emissions) optimizes optical efficiency by reducing quantum deficits. The specific emission characteristics of each phosphor component are designed to maximize light extraction and minimize energy loss, achieving superior color rendering and optical efficiency simultaneously
3Ease of manufacture
If conventional phosphors are used in white light emitting devices, then the manufacturing process is simple, but luminance is reduced when exposed to excitation source
Solution Approach 1:
The invention changes the emission parameters of the phosphor system by using multiple phosphors with specific emission peak wavelengths (530-550nm for green, 570-590nm for yellow, 620-650nm for red) and controlled FWHM values (80-120nm each). These parameter optimizations enable high luminance output while maintaining manufacturing simplicity through a single-layer phosphor structure
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 method enables the production of high-purity phosphors that selectively emit desired colors, improving color purity and rendition in white light emitting devices, enhancing their suitability for various applications beyond limited fields like portable terminals.
Implementation Method 1
A phosphor, which is excited by an excitation source having high energy such as ultraviolet or blue light to emit visible light
Implementation Method 2
a blue light emitting diode, which is one of light emitting devices that emit white light
Data Source
AI summary
Provided are a phosphor, a phosphor manufacturing method, and a white light emitting device. The phosphor is represented as a chemical formula of aMO-bAl2O3-cSi3N4, which uses light having a peak wavelength in a wavelength band of about 350 nm to about 480 nm as an excitation source to emit visible light having a peak wavelength in a wavelength band of about 480 nm to about 680 nm (where M is one kind or two kinds of elements selected from Mg, Ca, Sr, and Ba (0.2≦a/(a+b)≦0.9, 0.05≦b/(b+c)≦0.85, 0.4≦c/(c+a)≦0.9)).