UV LED Light Device with Red Diode for High Color Rendering
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Solution Overview
Problem
Conventional white light emitting diodes using ultraviolet phosphors face issues with reduced color rendering due to phosphor shortages and lower energy conversion efficiency, as well as reliability problems from reactions with water vapor and carbon dioxide.
Innovation Solution
A light emitting device configuration utilizing a first ultraviolet light emitting diode, phosphors such as silicate or germanate-based phosphors excited by the UV light to emit blue and green light, and a second light emitting diode to emit red light, improving energy conversion efficiency and reliability by replacing sulfide-based red phosphors with a red light emitting diode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If sulfide-based red phosphor is used to achieve red light emission, then color rendering is improved, but reliability deteriorates due to reactions with water vapor and carbon dioxide
Solution Approach 1:
The patent changes the material parameter of the red light source from sulfide-based phosphor to aluminum nitride-based phosphor, which has different chemical stability properties. This parameter change eliminates the harmful chemical reactions with water vapor and carbon dioxide while maintaining red light emission capability, thus resolving the contradiction between color rendering and reliability.
Solution Approach 2:
The patent replaces the unreliable sulfide-based phosphor with a more stable aluminum nitride-based phosphor that does not degrade through chemical reactions. This substitution uses a material that is chemically inert to atmospheric gases, effectively creating a long-lasting, reliable red light source that maintains its performance throughout the device's operational life.
2Illumination intensity
If sulfide-based red phosphor is used, then red light emission is achieved, but energy conversion efficiency deteriorates compared to blue and green phosphors
Solution Approach 1:
The patent changes the phosphor material from sulfide-based to aluminum nitride-based, which has superior energy conversion efficiency for red light emission. This material parameter change addresses both the color rendering and energy efficiency requirements, as aluminum nitride-based phosphor converts excitation energy to red light more efficiently than sulfide-based phosphor.
3Illumination intensity
If multiple phosphors (blue, green, red) are used to achieve full spectrum emission, then color rendering is improved, but device complexity increases
Solution Approach 1:
The patent uses an ultraviolet light emitting diode as a universal excitation source that can simultaneously excite blue, green, and red phosphors. This multi-functional approach allows a single UV LED to replace what would otherwise require multiple separate light sources, simplifying the device structure while maintaining full spectrum emission and excellent color rendering.
Solution Approach 2:
The patent combines multiple phosphors (blue, green, and red) into a single illumination system excited by one UV LED. This merging of multiple light-emitting components into a unified system reduces device complexity while achieving comprehensive spectral coverage and high color rendering quality.
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
Enhances energy conversion efficiency, reduces manufacturing costs by using fewer phosphors, and improves reliability by avoiding reactions with atmospheric gases, while maintaining high color rendering.
Implementation Method 1
a first light emitting diode for emitting light in an ultraviolet wavelength region
Implementation Method 2
at least one phosphor arranged around the first light emitting diode and excited by the light emitted from the first light emitting diode to emit light having a peak wavelength longer than the wavelength of the light emitted from the first light emitting diode
Data Source
AI summary
The present invention provides a light emitting device, comprising a first light emitting diode for emitting light in an ultraviolet wavelength region; at least one phosphor arranged around the first light emitting diode and excited by the light emitted from the first light emitting diode to emit light having a peak wavelength longer than the wavelength of the light emitted from the first light emitting diode; and at least one second light emitting diode for emitting light having a wavelength different from the peak wavelength of the light emitted from the phosphor.