Phosphor-Converted LED With Supplemental Red Diode
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Solution Overview
Problem
Conventional LED-based light sources with phosphor conversion have poor color-rendering indices due to insufficient red spectrum intensity and energy loss in blue to yellow conversion, leading to inefficient energy use and interference with feedback systems.
Innovation Solution
A light source comprising a blue LED, a red LED, and a green phosphor layer that converts blue light to green, with the red LED filling in the red spectrum, minimizing energy loss and avoiding infrared emission, thus improving efficiency and color rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If blue LED with yellow phosphor conversion is used, then light conversion efficiency is improved, but color-rendering index deteriorates due to insufficient red spectrum
Solution Approach 1:
The patent combines a blue LED with yellow phosphor conversion and a red LED in a single light source system. The blue LED provides efficient light conversion while the red LED supplements the red spectrum, achieving both high efficiency and good color rendering by merging two different light generation mechanisms.
Solution Approach 2:
The light source uses a composite approach combining phosphor converted light and direct LED emission. The yellow phosphor converts blue light to yellow, while the red LED emits directly in the red region, creating a composite spectrum that maintains both efficiency and color rendering quality.
2Reliability
If red LED is added to improve color rendering, then color-rendering index is improved, but device complexity increases
Solution Approach 1:
The patent merges the blue LED with yellow phosphor and red LED into a single integrated light source unit, sharing common optical path and control electronics, which reduces overall system complexity compared to separate lighting systems.
3Illumination intensity
If blue light is converted to yellow light, then white light appearance is achieved, but energy is lost as heat
Solution Approach 1:
The patent combines phosphor conversion (blue to yellow) with direct red LED emission to create white light. This hybrid approach reduces reliance on inefficient blue-to-yellow conversion alone, as the red LED directly generates red light without significant energy loss, thereby improving overall energy efficiency while maintaining white light appearance.
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 solution enhances light conversion efficiency, reduces energy waste, and provides a better color-rendering index by generating light across a broader spectrum perceived as white by humans, while avoiding spurious infrared interference with feedback systems.
Implementation Method 1
a green phosphor layer that converts blue light to green
Implementation Method 2
The second LED emits light at a third wavelength that is greater than the first wavelength
Data Source
AI summary
A light source having first and second LEDs and a phosphor layer that converts light generated by the first LED is disclosed. The first LED emits light at a first wavelength. The layer of phosphor is illuminated by the first LED, the phosphor being excited by light of the first wavelength to convert light of the first wavelength to a band of wavelengths having wavelengths between the first wavelength and a second wavelength. The second LED emits light at a third wavelength that is greater than the first wavelength. The phosphor is not substantially excited by light of the third wavelength. The combined light from the phosphor, and first and second LEDs is perceived as being white by a human observer.