Wavelength Conversion Element With Filled Cavities
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Solution Overview
Problem
Existing phosphor wheels used in projection devices face issues with thermal degradation and cavity formation, affecting light emitting efficiency and reliability, especially when using laser light sources.
Innovation Solution
A wavelength conversion element is developed with a wavelength conversion material dispersed in a binder to form a layer with cavities, where a filling material with higher refractive index than air is injected to fill some cavities, improving thermal conductivity, heat resistance, and conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If glass glue is used instead of silicone to mix with phosphor powder, then thermal conductivity and heat resistance are improved, but cavities are likely to form in the wavelength conversion area
Solution Approach 1:
The patent applies local quality by using different materials in different regions of the wavelength conversion element. Glass glue is used as the binder material to provide heat resistance and thermal conductivity, while a filling material is selectively introduced into cavities to locally address the cavity formation issue. This creates non-uniform material distribution where each region has properties optimized for its specific function.
Solution Approach 2:
The patent uses composite materials by combining glass glue as the binder with phosphor powder to form the wavelength conversion layer. The glass glue-phosphor powder composite provides both thermal management properties and wavelength conversion functionality. Additionally, the filling material creates a multi-material composite structure within the cavities, enhancing overall reliability.
2Productivity
If phosphor powder concentration is increased, then light emitting efficiency is improved, but volume percentage of cavities increases
Solution Approach 1:
The patent converts the harmful effect of cavity formation into a beneficial structure by intentionally creating a porous framework and then filling cavities with functional material. The cavities that would normally reduce reliability are transformed into locations for strategic material placement, where the filling material provides both structural support and optical functionality, turning a defect into a design feature.
Solution Approach 2:
The patent utilizes porous materials by creating a wavelength conversion layer with controlled porosity. The cavities form a porous structure that is then partially filled with filling material. This porous framework allows for optimized phosphor powder distribution and maintains structural integrity while enabling efficient light conversion.
3Ease of manufacture
If silicone is used as binder for phosphor powder, then ease of manufacture is improved, but thermal stability is worsened due to degradation under high temperature
Solution Approach 1:
The patent applies parameter changes by transitioning from silicone-based binder to glass glue-based binder, fundamentally changing the chemical composition and thermal properties of the wavelength conversion layer. This material substitution changes the temperature resistance parameter from low (silicone) to high (glass glue), enabling the system to withstand laser irradiation temperatures without degradation.
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 the reliability and conversion efficiency of the wavelength conversion element, module, and projection device by maintaining good thermal conductivity and reducing cavity volume percentage, leading to improved optical quality and reliability.
Implementation Method 1
laser light sources are used as an excitation light source for exciting phosphor powder to produce pure color light required by projectors
Implementation Method 2
a filling material with higher refractive index than air is injected to fill some cavities
Data Source
AI summary
A wavelength conversion element, a forming method of the wavelength conversion element, a wavelength conversion module and a projection device are provided. The wavelength conversion element includes a wavelength conversion material, a binder, a filling material and a plurality of cavities. The wavelength conversion material is dispersed in the binder to form a wavelength conversion layer. The filling material is located in the wavelength conversion layer. The cavities are located in the wavelength conversion layer, wherein the filling material fills some of the cavities. The wavelength conversion module includes a substrate and the above wavelength conversion element. The projection device includes the above wavelength conversion module, an excitation light source, a light valve and a projection lens. The disclosure enables the projection device to have good conversion efficiency and reliability.