White Light Emitting Device with Multi-Fluorescent Wavelength Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing LED light sources with a color temperature less than 5000K fail to achieve desirable color rendering index values, particularly with general color rendering index value Ra and special values R9-R15 not exceeding 90, which affects the accurate representation of object colors.
Innovation Solution
A white light emitting device incorporating a near-UV LED chip combined with a wavelength conversion layer containing three fluorescent materials that emit light in specific wavelength ranges (450-470 nm, 520-530 nm, and 630-650 nm), enhancing color rendering index values by optimizing the spectrum intensity ratios and full width at half maximum of these materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional LED chip with color temperature less than 5000K is used, then energy efficiency is maintained, but the color rendering index values (Ra and R9-R15) cannot all exceed 90
Solution Approach 1:
The wavelength conversion layer is segmented into multiple fluorescent materials with distinct emission characteristics. Specifically, the patent uses a first fluorescent material emitting in the blue region (450-470nm), a second fluorescent material emitting in the green region (520-530nm), and a third fluorescent material emitting in the red region (630-650nm). This segmentation allows each material to contribute to specific spectral regions, enabling all color rendering index values R9-R15 to exceed 90 while maintaining energy efficiency.
Solution Approach 2:
The patent employs a composite wavelength conversion layer combining multiple fluorescent materials with complementary emission spectra. The composite structure integrates a first fluorescent material (e.g., barium magnesium aluminate doped with europium), a second fluorescent material (e.g., calcium aluminum nitride doped with europium), and a third fluorescent material (e.g., calcium strontium aluminate doped with europium). This composite approach achieves high color rendering index values while maintaining the energy efficiency of LED technology.
2Reliability
If the wavelength conversion layer uses multiple fluorescent materials, then color rendering index values improve, but the device structure becomes more complex
Solution Approach 1:
The patent applies local quality by assigning specific fluorescent materials to specific spectral regions. The first fluorescent material is optimized for blue light emission (450-470nm) to enhance color rendering in the blue region, the second fluorescent material is optimized for green light emission (520-530nm) to enhance color rendering in the green region, and the third fluorescent material is optimized for red light emission (630-650nm) to enhance color rendering in the red region. This localized optimization ensures high color accuracy while managing structural complexity through functional specialization.
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 device achieves a color temperature less than 5000K with general and special color rendering index values greater than 90, improving color accuracy and rendering capabilities.
Implementation Method 1
The wavelength conversion layer includes at least three wavelength-difference fluorescent materials, wherein one is capable of being excited to emit light with a peak wavelength of 450 nm to 470 nm, another is capable of being excited to emit light with a peak wavelength of 520 nm to 530 nm and still another is capable of being excited to emit light with a peak wavelength of 630 nm to 650 nm
Data Source
AI summary
A white light emitting device includes an LED chip capable of emitting light with a peak wavelength of 390 to 430 nm, and a wavelength conversion layer including first, second and third fluorescent materials. The first fluorescent material is capable of being excited to emit light with a peak wavelength of 450 to 470 nm. The second fluorescent material is capable of being excited to emit light with a peak wavelength of 450 to 470 nm. The third fluorescent material is capable of being excited to emit light with a peak wavelength of 630 to 650 nm. Light emitted by the white light emitting device has a color temperature below 5000 K, and a general color rendering index value (Ra) and special color rendering index values (R9-R15) all greater than 90.