Wavelength Conversion Light Source with Color Filter and Rotating Phosphor
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Solution Overview
Problem
Conventional high luminance light sources using red phosphors for generating red color light suffer from lower conversion efficiencies, higher heat generation, and increased costs, resulting in reduced luminous flux and reliability compared to green and yellow phosphors.
Innovation Solution
Employing a broad band emission phosphor with a dominant wavelength shorter than 590 nm, combined with a color filter to generate red light, which shifts the dominant wavelength and increases luminous flux, and using a moving phosphor device to reduce heat generation, such as a rotating phosphor disk or plate, with a blue excitation source and a dichroic filter to enhance red light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If red phosphors are used to generate red color light, then red light emission is achieved, but conversion efficiency is low and heat generation is high
Solution Approach 1:
The patent changes the key parameter from using red phosphor directly to using yellow phosphor with dominant wavelength shorter than 590 nm, combined with a color filter. This parameter change achieves higher conversion efficiency (yellow phosphor has smaller Stokes shift) while the color filter selects the appropriate wavelength range, resolving the contradiction between conversion efficiency and heat generation.
Solution Approach 2:
The patent introduces a color filter as an intermediary component between the yellow phosphor and the output. The filter mediates the light from yellow phosphor to produce the desired red color light, allowing high efficiency phosphor to be used while achieving the required color output, thus resolving the energy loss and heat generation problems.
2Illumination intensity
If red phosphors are used to generate red color light, then red light emission is achieved, but luminous flux is reduced
Solution Approach 1:
The patent changes the phosphor material parameter from red phosphor to yellow phosphor with dominant wavelength shorter than 590 nm, which has inherently higher conversion efficiency and greater radiant power. Combined with the color filter that transmits red wavelengths, this achieves higher luminous flux while maintaining energy efficiency.
3Device complexity
If stationary phosphor device is used, then simple structure is achieved, but heat generation increases
Solution Approach 1:
The patent introduces a moving phosphor device (rotating phosphor disk or plate) to dynamically distribute the excitation light over time and space. This movement prevents localized heat accumulation that would occur with stationary phosphor, reducing overall heat generation while adding only moderate mechanical complexity to the system.
4Loss of energy
If yellow phosphor with color filter is used instead of red phosphor, then conversion efficiency increases, but device complexity increases
Solution Approach 1:
The patent uses a color filter as an intermediary component that adds minimal complexity while enabling the high-efficiency yellow phosphor to produce the desired red light output. The filter is a relatively simple optical element that achieves wavelength selection without requiring complex mechanical or electronic systems, thus resolving the contradiction between efficiency and complexity.
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 achieves higher luminous flux and brightness with reduced heat generation and cost, while maintaining high conversion efficiency, by utilizing yellow phosphors with a color filter to produce red light, outperforming traditional red phosphor-based systems.
Implementation Method 1
a solid-state light source 100 is used to emit an excitation light through a focusing system 102, and a rotation phosphor wheel 104, in which several color phosphors are coated in different segments, is excited by the excitation light source to generate a light with a colored light sequence
Implementation Method 2
using a blue excitation source and a dichroic filter to enhance red light output
Implementation Method 3
using a moving phosphor device to reduce heat generation, such as a rotating phosphor disk or plate
Data Source
AI summary
A light source device uses a wavelength down conversion material for absorbing an excitation light and generating a converted light, and a color filter for filtering the converted light to generate a different color light as output. The wavelength conversion material is a yellow or green phosphor which absorbs blue or UV light and generates a yellow or green converted light, which has a sufficiently wide spectrum to cover some of the red color region. The color filter only allows the red component of the converted light to be output. This system is more energy efficient than using a red phosphor. This light source may be implemented as a moving phosphor wheel having multiple segments, one of which being the yellow or green phosphor with the corresponding color filter, the other segments being used to generate other colored lights such as green and blue lights.