Wavelength Conversion Member Phosphor Gradient Chromaticity Control
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Solution Overview
Problem
Wavelength conversion members with phosphor powder dispersed in a glass matrix often exhibit chromaticity variations and require excessive material removal to achieve desired chromaticity, leading to inefficiencies in productivity.
Innovation Solution
A wavelength conversion member with a glass matrix and phosphor particles, where the concentration of phosphor particles decreases from the first principal surface to the second, allowing for precise adjustment of chromaticity through controlled polishing, and a production method involving slurry application, sedimentation, and stacking of green sheets with varying phosphor concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If phosphor powder is dispersed in a glass matrix and the material is polished to reduce thickness, then the chromaticity can be adjusted, but significant material must be ground away which reduces productivity
Solution Approach 1:
The phosphor particles are pre-distributed in specific concentration gradients within the glass matrix before the wavelength conversion member is formed. This preliminary arrangement of phosphor concentrations in different regions allows the final chromaticity to be controlled by the initial distribution pattern rather than requiring extensive post-manufacturing material removal, thereby improving productivity while maintaining chromaticity accuracy.
Solution Approach 2:
The invention creates non-uniform phosphor particle concentration distributions within different regions of the glass matrix. By having higher concentrations in certain areas and lower concentrations in others, the wavelength conversion member achieves spatially varying chromaticity characteristics that can be precisely tuned for the desired output without requiring uniform polishing across the entire surface.
2Device complexity
If phosphor powder is dispersed uniformly in a glass matrix, then the structure is simple, but chromaticity variations occur making accurate chromaticity adjustment difficult
Solution Approach 1:
The invention transitions from uniform phosphor distribution to a controlled non-uniform distribution where phosphor particle concentrations vary systematically across different regions of the glass matrix. This local variation in phosphor concentration enables precise chromaticity control in different areas while maintaining a relatively simple overall glass matrix structure, resolving the contradiction between structural simplicity and chromaticity accuracy.
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
Enables accurate and efficient adjustment of chromaticity with reduced material loss, enhancing productivity and luminescent color consistency.
Implementation Method 1
a wavelength conversion member capable of absorbing part of the light from the LED to convert it to a yellow light
Implementation Method 2
allowing the phosphor particles to sediment downward before completion of the drying to obtain first and second green sheets
Data Source
Figure 1~3
Figure 4~5
Figure 6(a)~6(d)
AI summary
Provided is a wavelength conversion member that can be adjusted in chromaticity readily and with high accuracy and a production method for the wavelength conversion member. A wavelength conversion member 1 having a first principal surface 1a and a second principal surface 1b opposed to each other includes a glass matrix 2 and phosphor particles 3 disposed in the glass matrix 2, wherein a concentration of the phosphor particles 3 in the first principal surface 1a is higher than a concentration of the phosphor particles 3 in a portion 20 µm inward from the first principal surface 1a, a concentration of the phosphor particles 3 in the second principal surface 1b is lower than a concentration of the phosphor particles 3 in a portion 20 µm inward from the second principal surface 1b, and the concentration of the phosphor particles 3 in the first principal surface 1a is higher than the concentration of the phosphor particles 3 in the second principal surface 1b.