Reflection-Type Wavelength Converter With Ceramic Phosphor Heat Dissipation
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Solution Overview
Problem
Wavelength converting members with inorganic binders face challenges in maintaining luminescent performance when exposed to high-energy laser light due to heat generation and thermal quenching, limiting their use in high-energy environments.
Innovation Solution
A reflection-type wavelength converting member with a substrate made of inorganic material, a phosphor layer containing YAG-based or LAG-based phosphor particles, and a translucent ceramic binder, optimized with a specific thickness-to-particle-size ratio and porosity to reduce thermal resistance and maintain fluorescent performance under high-intensity light exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an inorganic binder is used in the wavelength converting member, then heat resistance of the material is enhanced, but the phosphor particles still generate heat under laser irradiation and eventually lose luminescent performance
Solution Approach 1:
The patent employs a porous ceramic structure as the wavelength converting member, where the porous architecture provides thermal pathways for heat dissipation while maintaining the inorganic binder's inherent heat resistance. The porous structure allows heat generated by phosphor particles under laser irradiation to be efficiently conducted away, preventing thermal accumulation that would otherwise cause luminescent performance degradation.
Solution Approach 2:
The patent creates a composite material system combining phosphor particles embedded in a porous ceramic matrix. This composite structure integrates the luminescent properties of phosphor particles with the thermal management capabilities of the porous ceramic, achieving both high heat resistance and maintained luminescent performance under laser irradiation.
2Object-affected harmful factors
If a ring-shaped wavelength converting member is rotated at high speed to prevent burning, then the burning problem is solved, but the size and complication of tools and apparatuses increase
Solution Approach 1:
The patent extracts the rotational motion requirement from the system by developing a stationary wavelength converting member with inherent burn prevention capabilities. The porous ceramic structure provides thermal management that prevents burning without requiring high-speed rotation, thereby eliminating the need for complex rotational mechanisms and reducing overall device complexity.
Solution Approach 2:
The patent replaces the mechanical rotation system with a thermal conduction-based solution. Instead of using mechanical rotation to distribute heat and prevent burning, the porous ceramic structure uses thermal conduction pathways to dissipate heat, substituting a complex mechanical system with a simpler thermal management approach.
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 ensures that the phosphor layer retains over 70% emission efficiency even at high power densities, preventing thermal quenching and maintaining fluorescent performance, thus enabling continuous high-output emission without performance degradation.
Implementation Method 1
phosphor particles that absorb light and emit converted light
Implementation Method 2
a translucent ceramic that binds the phosphor particles to one another
Implementation Method 3
reflects the light on a reflection surface to emit the light as illumination light
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3(a)~3(b)
AI summary
The invention provides a fluorescent member which has high thermal conductivity and thus can prevent an increase in temperature of a phosphor layer and can maintain fluorescent performance even when irradiated with source light having a high intensity, and provides a light-emitting device having such a member. A reflection-type wavelength converting member 100 converts light with a specific wavelength to light with other wavelength and also reflects the light on a reflection surface to emit the light as illumination light. The wavelength converting member 100 includes a substrate 110 including an inorganic material, and a phosphor layer 120 disposed on the substrate 110 and including phosphor particles 122 that absorb light and emit converted light and a translucent ceramic 121 that binds the phosphor particles 122 to one another. The ratio of the thickness of the phosphor layer 120 to the average particle size of the phosphor particles 122 is less than 30. The reflection surface on which the converted light is reflected is a surface of the substrate 110 or a surface of a reflector adjacent to the wavelength converting member.