Beta-Sialon Phosphor Particles for Projector Wavelength Conversion
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Solution Overview
Problem
Phosphors used in wavelength conversion members for projectors, particularly those converting blue light to green or red, lack optimal light emitting efficiency and color gamut performance due to inadequate design for projector applications.
Innovation Solution
Development of β-type sialon phosphor particles integrated with a specific sheet producing procedure and optical characteristics, including a mixture with silicone resin OE-6630, to achieve a cured sheet with controlled light transmission and conversion efficiency, ensuring It/Ii ≤ 0.50 and Ip/Ii ≥ 0.03, enhancing wavelength conversion efficiency and color gamut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phosphor particles of related art are used in wavelength conversion member, then the phosphor layer can be formed, but the light emitting efficiency and color gamut performance are insufficient
Solution Approach 1:
The patent changes the particle size parameters of β-type sialon phosphor particles to D50=3.4μm and D90=6.4μm, and controls the volume concentration to 15-40 vol%, which optimizes the balance between light emitting efficiency and color gamut performance in the wavelength conversion member
Solution Approach 2:
The patent uses composite material consisting of β-type sialon phosphor particles combined with specific resin materials to create a wavelength conversion layer that achieves both high light emitting efficiency and excellent color gamut performance
2Productivity
If phosphor volume concentration is increased to improve light conversion, then conversion efficiency improves, but heat generation increases
Solution Approach 1:
The patent optimizes the phosphor volume concentration parameter to a specific range of 15-40 vol%, which achieves high wavelength conversion efficiency while controlling heat generation by preventing excessive phosphor aggregation
Solution Approach 2:
The patent creates uniform local distribution of phosphor particles throughout the wavelength conversion layer, ensuring consistent conversion efficiency across the entire component while distributing heat generation evenly to prevent localized overheating
3Productivity
If phosphor layer thickness is increased to improve conversion, then conversion efficiency improves, but light transmission performance deteriorates
Solution Approach 1:
The patent optimizes the thickness parameter of the wavelength conversion layer to achieve the best balance between conversion efficiency and light transmission, ensuring sufficient conversion while maintaining adequate light output intensity
Solution Approach 2:
The patent ensures uniform phosphor distribution throughout the layer thickness, creating consistent local conversion properties that maximize overall efficiency while maintaining good light transmission characteristics
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 particles improve wavelength conversion efficiency and increase the color gamut of projectors by optimizing light transmission and conversion, while minimizing heat generation due to a thin phosphor layer design.
Implementation Method 1
a wavelength conversion member in which a wavelength conversion layer including a phosphor which converts blue light from the blue light source into green light or red light is formed
Implementation Method 2
an intensity of light emitted from the other surface side of the cured sheet at a peak wavelength in the range of 450 nm to 460 nm is defined as It [W/nm], and an intensity of the light emitted from the other surface side of the cured sheet at a peak wavelength in a range of 500 nm to 560 nm is defined as Ip [W/nm]
Data Source
AI summary
Phosphor particles for producing a wavelength conversion member of a projector, including β-type sialon. A cured sheet having a film thickness of 50±5 μm produced by using the particle satisfies the following optical characteristics: when an intensity at a peak wavelength of blue light emitted from a blue LED having a peak wavelength between 450 to 460 nm is defined as Ii [W/nm], and in a case where the blue light is emitted to one surface side of the cured sheet, when an intensity of light emitted from the other surface side of the cured sheet at a peak wavelength between 450 to 460 nm is defined as It [W/nm] and an intensity thereof at a peak wavelength between 500 to 560 nm is defined as Ip [W/nm], It/Ii is equal to or less than 0.50 and Ip/Ii is equal to or more than 0.03.