Phosphor Device for High-Purity Red Light via Segmented Conversion
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Solution Overview
Problem
Current projector illumination systems using solid-state light-emitting elements for red light production face issues with low light purity, poor thermal stability, and high manufacturing costs, as well as inefficient conversion efficiency.
Innovation Solution
A phosphor device incorporating a first and second phosphor agent with specific wavelength peaks, integrated to enhance the purity, luminance, and luminous intensity of the red light, while improving thermal stability and reducing absorption, using a reflective substrate with tailored reflectance spectra for increased output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a yellow phosphor agent is used to convert blue light to red light, then the illumination system can produce red light, but the purity and conversion efficiency of the red light are poor
Solution Approach 1:
The patent divides the single yellow phosphor conversion process into two separate phosphor conversion stages: first converting blue light to green light using a green phosphor agent, then converting green light to red light using a red phosphor agent. This segmentation allows each phosphor to operate in its optimal wavelength range, improving both the purity and efficiency of red light production while avoiding the spectral impurity issues of direct blue-to-red conversion.
2Illumination intensity
If a red phosphor agent is used to convert blue light to red light, then red light can be produced, but the thermal stability is poor
Solution Approach 1:
The patent segments the wavelength conversion process into two stages with intermediate green light production. The red phosphor agent converts green light (520-560nm) to red light, rather than directly converting blue light. This intermediate step reduces the thermal load on the red phosphor and improves its thermal stability, as the energy gap between green and red photons is smaller and generates less heat.
3Manufacturing precision
If a solid-state light-emitting element directly emits red laser light, then high-purity red light can be obtained, but the manufacturing cost is expensive and additional cooling system is required
Solution Approach 1:
The patent introduces green light as an intermediary in the wavelength conversion process. Instead of directly generating red laser light, the system uses green phosphor conversion as a mediator step between blue light excitation and red light output. This intermediary approach achieves high-purity red light through phosphor down-conversion rather than direct laser emission, eliminating the need for complex cooling systems and reducing manufacturing costs while maintaining spectral purity.
4Productivity
If the first phosphor agent emits light with a wavelength peak that overlaps with the second phosphor agent's absorption spectrum, then the conversion efficiency is reduced due to increased absorption
Solution Approach 1:
The patent optimizes the spectral characteristics of each phosphor agent to create local quality differences in their emission and absorption profiles. The green phosphor agent is selected to emit light with a wavelength peak (520-560nm) that has minimal overlap with the red phosphor agent's absorption spectrum. This local spectral optimization reduces parasitic absorption and maximizes conversion efficiency at each stage of the wavelength conversion process.
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 phosphor device achieves higher light purity and luminous intensity, improved thermal stability, and reduced manufacturing costs by integrating specific wavelength peaks and reflective spectra, enhancing the overall performance of the illumination system.
Implementation Method 1
through converting the first waveband light into a second waveband light integrated by a first color light and a second color light having specific wavelength peaks
Implementation Method 2
reflective substrate with tailored reflectance spectra for increased output
Data Source
AI summary
A phosphor device of an illumination system emitting a first waveband light includes a substrate and a phosphor layer formed on the substrate. The phosphor layer includes a first phosphor agent and a second phosphor agent. The first waveband light is converted into a first color light by the first phosphor agent. The second phosphor agent is distributed over the first phosphor agent and mixed with the first phosphor agent, and the first waveband light is converted into a second color light by the second phosphor agent. The first color light and the second color light are integrated into the second waveband light. The difference between the first wavelength peak of the first color light and the second wavelength peak of the second color light is 50 to 100 nanometers. Therefore, the advantages of increasing the purity, the luminance and the luminous intensity of specific color light are achieved.