Light Emitting Device Spectral Overlap for Sunlight Color Rendering
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Solution Overview
Problem
Existing light emitting devices fail to achieve color rendering properties similar to sunlight, as they often have limited overlap in emission spectra between the light emitting element and phosphor, leading to suboptimal color fidelity and brightness.
Innovation Solution
A light emitting device with a light emitting element having a peak wavelength between 411 nm and 421 nm, combined with phosphors emitting at longer wavelengths, achieving an overlap width of 71-81 nm, and utilizing specific phosphor types like alkaline earth halophosphate, β-SiAlON, and CASON to enhance color rendering indexes Rf and Rg.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional light emitting devices use light emitting elements with peak wavelengths outside the 411-421 nm range or phosphors with insufficient spectral overlap, then device complexity and manufacturing are simplified, but color rendering properties deteriorate and the emitted light deviates from sunlight characteristics
Solution Approach 1:
The patent applies parameter changes by precisely controlling the peak wavelength of the light emitting element (411-421 nm) and the spectral overlap width (71-81 nm) to optimize color rendering properties. This specific parameter range selection enables the device to emit light with Rf≥90 and 95≤Rg≤105, closely matching sunlight characteristics while maintaining manufacturing feasibility through defined spectral parameters.
Solution Approach 2:
The patent employs composite materials by combining a light emitting element with specific phosphors that have complementary emission spectra. The phosphors are selected and configured to achieve the target spectral overlap width, creating a composite system where the light emitting element and phosphors work together to produce sunlight-like color rendering properties.
2Illumination intensity
If the emission spectra of the light emitting element and phosphor have limited overlap, then device structure is simplified, but color fidelity and brightness deteriorate
Solution Approach 1:
The patent optimizes illumination intensity by controlling the spectral overlap parameter between the light emitting element and phosphors to be within 71-81 nm. This parameter optimization ensures sufficient spectral interaction to generate bright, high-quality light with Rf≥90 and 95≤Rg≤105, while avoiding excessive complexity through well-defined spectral parameters.
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 superior color rendering properties, with Rf≥90 and 95≤Rg≤105, closely mimicking sunlight's color fidelity and brightness, surpassing conventional devices.
Implementation Method 1
a light emitting element that emits a light having a peak wavelength of not less than 411 nm and not more than 421 nm
Implementation Method 2
a phosphor that emits a fluorescence having a longer peak wavelength than the peak wavelength of the 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 wavelength of not less than 411 nm and not more than 421 nm, and a phosphor that emits a fluorescence having a longer peak wavelength than the peak wavelength of the light emitted from the light emitting element. An emission spectrum of only the light emitting element and an emission spectrum of only the phosphor overlap each other while having an overlap width of not less than 71 nm and not more than 81 nm. The overlap width is defined as a wavelength difference between a long wavelength side point at a 0.1% height of a peak height of the emission spectrum of only the light emitting element and a short wavelength side point at a 0.1% height of a highest peak of the emission spectrum of only the phosphor.