Wavelength Conversion Member Manufacturing via Hot Isostatic Pressing
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Solution Overview
Problem
Existing wavelength conversion members for LEDs and LDs suffer from reduced light conversion efficiency due to the incorporation of glass components and difficulty in achieving high-density sintered bodies, leading to decreased emission intensity.
Innovation Solution
A method involving a green body composed of yttrium-aluminum-garnet phosphor with specific composition and high-purity alumina particles, subjected to primary sintering followed by hot isostatic pressing (HIP) treatment for secondary sintering, to produce a dense and efficient wavelength conversion member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If glass powder is mixed with inorganic phosphor powder to form a sintered body, then the manufacturing process is simplified, but light conversion efficiency decreases remarkably due to glass component mixing and hole formation
Solution Approach 1:
The invention extracts and removes the glass component from the sintered body composition, using only inorganic phosphor powder and sintering aids. This eliminates the harmful effects of glass mixing while maintaining manufacturing simplicity through the use of conventional sintering processes without glass-based binders.
Solution Approach 2:
The invention changes the compositional parameters by specifying precise ratios of inorganic phosphor powder to sintering aids, and controlling sintering temperature and atmosphere parameters. This enables high-density sintering without glass components, resolving the contradiction between ease of manufacture and light conversion efficiency.
2Ease of manufacture
If glass is used as a binder in the sintered body, then the green body can be formed easily, but high-density sintering cannot be achieved and holes remain inside the sintered body
Solution Approach 1:
The invention removes glass from the binder system and replaces it with organic binders and sintering aids that do not create harmful residues. This allows green body formation to proceed without glass while enabling complete binder burnout and high-density sintering through controlled heating schedules.
Solution Approach 2:
The invention incorporates preliminary binder burnout steps in the sintering schedule before final densification. This preliminary action removes organic binders completely, preventing hole formation and enabling subsequent high-density sintering without the constraints of glass-based binders.
3Device complexity
If conventional sintering is used without hot isostatic pressing, then the manufacturing process is simpler, but the sintered body contains holes and has reduced light conversion efficiency
Solution Approach 1:
The invention changes the sintering parameters by introducing hot isostatic pressing with specific temperature, pressure, and atmosphere conditions. This parameter change eliminates holes through uniform densification while maintaining phosphor particle integrity, resolving the contradiction between process complexity and light conversion efficiency.
Solution Approach 2:
The invention uses a composite approach combining conventional sintering with hot isostatic pressing, where the first sintering creates the basic structure and the HIP treatment densifies it. This composite process achieves high density and light conversion efficiency while keeping the overall manufacturing approach practical.
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 method results in a wavelength conversion member with enhanced emission intensity and light conversion efficiency, minimizing voids and maintaining the original light body color of the YAG phosphor, suitable for use in light-emitting devices.
Implementation Method 1
secondary-sintering the first sintered body by applying a hot isostatic pressing (HIP) treatment to obtain a second sintered body
Implementation Method 2
annealing the second sintered body in an oxygen-containing atmosphere
Implementation Method 3
an yttrium-aluminum-garnet phosphor with a composition represented by Formula (I) below; wherein a and b satisfy 0≤a≤0.3 and 0≤b≤0.022
Data Source
AI summary
A method for manufacturing a wavelength conversion member that offers a high emission intensity and a high light conversion efficiency is provided. The method for manufacturing a wavelength conversion member includes providing a green body containing an yttrium-aluminum-garnet phosphor with a composition represented by Formula (I) below and alumina particles with an alumina purity of 99.0% by mass or more, primary-sintering the green body to obtain a first sintered body, and secondary-sintering the first sintered body by applying a hot isostatic pressing (HIP) treatment to obtain a second sintered body.(Y1-a-bGdaCeb)3Al5O12 (I)wherein a and b satisfy 0≤a≤0.3 and 0≤b≤0.022.