Wavelength Converter Binder Gradient for Low-Temperature Adhesion
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Solution Overview
Problem
Existing wavelength converters require high-temperature manufacturing processes, which can degrade metal substrates and compromise adhesion between the substrate and the optical conversion layer, leading to poor thermal management and light extraction efficiency.
Innovation Solution
A wavelength converter design featuring an optical conversion layer with an amorphous binder and granular binder particulates of smaller average particle size than the inorganic particles, where the binder particulate concentration ratio is higher near the substrate, ensuring strong adhesion and reduced thermal stress, allowing for low-temperature manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If high-temperature manufacturing process is used to form the optical conversion layer, then the optical conversion layer can be properly formed, but the metal substrate and optical conversion inorganic particles are degraded
Solution Approach 1:
The patent changes the temperature parameter of the manufacturing process from high temperature (550°C) to low temperature, enabling the formation of optical conversion layers on metal substrates without degrading the substrate or inorganic particles. This is achieved by using a binder composition that cures at low temperatures to form an inorganic binder portion.
Solution Approach 2:
The patent introduces a binder composition as an intermediary material between the metal substrate and optical conversion inorganic particles. This binder contains a curable resin and inorganic particles that, when cured, form an inorganic binder portion enabling low-temperature bonding without direct high-temperature contact between the substrate and phosphor particles.
2Device complexity
If the optical conversion layer is formed with uniform binder distribution, then the structure is simple, but the adhesion strength between substrate and optical conversion layer is insufficient
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of inorganic binder particulates within the optical conversion layer. The binder particulate concentration is specifically higher in regions adjacent to the substrate portion, providing enhanced adhesion strength at the critical substrate-interface while maintaining overall structural integrity.
3Illumination intensity
If the metal substrate is used to reflect light, then light extraction efficiency is improved, but thermal management becomes problematic due to heating during manufacturing
Solution Approach 1:
The patent changes the temperature parameter of the manufacturing process from high temperature to low temperature, enabling the use of metal substrates for light reflection without subjecting them to degrading temperatures. The low-curing-temperature binder system allows metal substrates to be used while maintaining both their optical reflective properties and thermal stability.
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 design prevents substrate and inorganic particle degradation during manufacturing, enhances adhesion between the substrate and the optical conversion layer, and improves light extraction efficiency while maintaining high thermal conductivity.
Implementation Method 1
an optical conversion layer composed of a plurality of optical conversion inorganic particles which emit light by being irradiated with excitation light
Data Source
Figure 1~2
Figure 3~4
AI summary
A wavelength converter (1) includes: a substrate portion (10); and an optical conversion layer (30) including optical conversion inorganic particles (40) and an inorganic binder portion (50), wherein the inorganic binder portion (50) includes: an amorphous binder (52); and granular binder particulates (51) with an average particle size smaller than an average particle size of the optical conversion inorganic particles (40), and when a ratio of an average volume concentration of the binder particulates (51) in the substrate-side portion (31) with respect to an average volume concentration of the optical conversion inorganic particles (40) in the substrate-side portion (31) is defined as a substrate-side binder particulate concentration ratio RFs and, when a ratio of an average volume concentration of the binder particulates (51) in the non-substrate-side portion (32) with respect to an average volume concentration of the optical conversion inorganic particles (40) in the non-substrate-side portion (32) is defined as a non-substrate-side binder particulate concentration ratio RFo, the substrate-side binder particulate concentration ratio RFs is larger than the non-substrate-side binder particulate concentration ratio RFo.