Phosphor Wheel Materials for Heat-Stable Image Projection Color
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Solution Overview
Problem
Image projection apparatuses face challenges in providing highly efficient light output and maintaining color purity due to temperature increases, which affect the luminous efficiency of phosphors.
Innovation Solution
The apparatus incorporates a phosphor wheel with specific phosphor compositions and configurations, including a substrate with yellow and green phosphors, a reflective layer, and a color filter to sequentially output yellow, green, and red light, enhancing light output and color purity despite temperature increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the image projection apparatus increases light output efficiency, then the temperature increases, but the luminous efficiency of phosphor decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor materials, specifically using (Lu1-xYx)3Al5O12:Ce for green phosphor and Y3(Al1-y,Gdy)5O12:Ce for yellow phosphor. This compositional parameter change enables the phosphors to maintain high luminous efficiency even at elevated temperatures, thus resolving the contradiction between increased light output efficiency and maintained phosphor performance
Solution Approach 2:
The patent employs composite phosphor materials with specific chemical compositions rather than single-material phosphors. The use of doped rare-earth phosphors like (Lu1-xYx)3Al5O12:Ce combines multiple elements to achieve both high light output efficiency and thermal stability, allowing the system to simultaneously improve productivity while maintaining reliability
2Manufacturing precision
If the phosphor wheel uses specific phosphor compositions to improve color purity, then the manufacturing complexity increases
Solution Approach 1:
The patent specifies precise compositional parameters for the phosphors, such as the ratio parameters x, y, and z in (Lu1-xYx)3Al5O12:Ce and Y3(Al1-y,Gdy)5O12:Ce. These parameter specifications enable consistent color purity while providing clear manufacturing guidelines, thus achieving high manufacturing precision without excessive 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 provides highly efficient light output and improved color purity by using (Lu1-xYx)3Al5O12:Ce for green phosphors, Y3(Al1-y,Gdy)5O12:Ce for yellow phosphors, and Y(Al1-z,Gaz,)5O12:Ce for red phosphors, along with optimized region sizes and a reflective layer, ensuring efficient performance even at elevated temperatures.
Implementation Method 1
a phosphor wheel configured to output a plurality of colors of light based on the blue light incident upon rotation
Data Source
AI summary
An image projection apparatus is disclosed. The image projection apparatus according to an embodiment of the present disclosure includes: a light source configured to output blue light; and a phosphor wheel configured to output a plurality of colors of light based on the blue light incident upon rotation, wherein the phosphor wheel includes: a substrate; a yellow phosphor disposed in a first region on the substrate for output of yellow light; and a green phosphor disposed in a second region on the substrate for output of green light, wherein the green phosphor includes (Lu1−xYx)3Al5O12, with 0<x<0.8. Accordingly, highly efficient light output may be provided, and color purity may be improved.