Light Emitting Device with Composite Phosphor for Sunlight-Like Color Rendering
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Solution Overview
Problem
Existing light emitting devices do not achieve color rendering properties close to sunlight, as measured by general and special color rendering indices, limiting their ability to mimic natural light sources.
Innovation Solution
A light emitting device comprising a light emitting element with a peak emission wavelength between 410 nm and 425 nm, combined with a phosphor that emits fluorescence at a longer wavelength, achieving a general color rendering index Ra of at least 95 and a color rendering index Rf of at least 96, with the mixed light's color rendering indices closer to those of sunlight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional light emitting devices use standard phosphor combinations, then manufacturing is simpler, but color rendering properties are insufficient (Ra < 95, Rf < 96)
Solution Approach 1:
The patent uses a composite phosphor system comprising multiple phosphors with specific characteristics (first phosphor with 450-480nm peak, second phosphor with 580-650nm peak, third phosphor with 520-560nm peak). This composite approach enables achieving Ra≥95 and Rf≥96 by combining the emission spectra of different phosphors to closely match sunlight, resolving the contradiction between manufacturing simplicity and color rendering precision.
Solution Approach 2:
The patent specifies precise parameter ranges for the light emitting element (peak wavelength 405-425nm, FWHM 30-50nm) and each phosphor component (peak wavelengths, FWHM values, and mixing ratios). By controlling these parameters within defined ranges, the invention achieves superior color rendering (Ra≥95, Rf≥96) while providing manufacturing guidance that balances precision requirements with production feasibility.
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 emits light with improved color rendering properties, achieving indices of Ra ≥ 96, Rf ≥ 96, and Rg ≥ 98, closely resembling sunlight, thereby enhancing color fidelity and brightness.
Implementation Method 1
a light emitting element that emits a light having a peak emission wavelength in a wavelength range of not less than 410 nm and not more than 425 nm
Implementation Method 2
a phosphor emitting a fluorescence having a peak at a longer wavelength side than the peak emission wavelength of light emitted from the light emitting element
Data Source
AI summary
A light emitting device includes a light emitting element that emits a light having a peak emission wavelength in a wavelength range of not less than 410 nm and not more than 425 nm, and a phosphor emitting a fluorescence having a peak at a longer wavelength side than the peak emission wavelength of light emitted from the light emitting element. A general color rendering index Ra of fluorescence emitted from the phosphor is not less than 95. A general color rendering index Ra of mixed light of light emitted from the light emitting element and fluorescence emitted from the phosphor is higher than a general color rendering index Ra of fluorescence emitted from the phosphor. A color rendering index Rf of the mixed light is not less than 96.