Polysilazane Ceramic Wavelength Conversion for LED Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The preparation of a ceramic layer using a sol-gel medium requires high-temperature calcination, leading to deterioration of the phosphor or LED element, and the curing of polysilazane with dispersed phosphor results in gaps that allow moisture permeation, causing further deterioration.
Innovation Solution
A light emission device is developed with a ceramic layer formed from polysilazane containing a phosphor and inorganic fine particles, which eliminates the need for high-temperature calcination and fills gaps between the phosphor and ceramic material, preventing moisture permeation and deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic layer is formed using a sol-gel medium, then a ceramic coating can be obtained, but high-temperature calcination (not less than 700°C) is required which causes deterioration of the phosphor or LED element
Solution Approach 1:
The patent changes the chemical composition parameters of the sol-gel medium by incorporating specific organic-inorganic hybrid components that allow the ceramic layer to form at lower temperatures (below 700°C), thereby preventing phosphor deterioration while still achieving the desired ceramic coating properties
Solution Approach 2:
The patent uses composite sol-gel materials combining organic and inorganic components, creating a hybrid ceramic precursor that can undergo low-temperature sintering to form a dense ceramic layer without requiring high-temperature calcination that would damage the phosphor
2Reliability
If polysilazane with dispersed phosphor is cured, then a ceramic layer can be formed, but gaps are produced at the interface between phosphor and ceramic material which allow moisture permeation and cause phosphor deterioration
Solution Approach 1:
The patent applies local quality improvement by modifying the interface region between phosphor particles and ceramic matrix through controlled sol-gel chemistry, creating a transition zone that eliminates gaps and prevents moisture penetration while maintaining the overall ceramic structure
Solution Approach 2:
The patent introduces an intermediary layer or modification at the phosphor-ceramic interface through the sol-gel process, where the gel structure acts as a mediator that fills gaps and creates a seamless transition, preventing moisture pathways while bonding the phosphor to the ceramic matrix
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 addition of inorganic fine particles allows for a ceramic layer formation without high-temperature calcination, preventing phosphor and LED element deterioration and maintaining fluorescence intensity even after storage at high temperature and humidity.
Implementation Method 1
the produced gaps induce permeation of moisture, resulting in deterioration of the phosphor
Implementation Method 2
the LED element emitting light of a specific wavelength and the wavelength conversion section converting the light emitted from the LED element to light of a specific wavelength
Data Source
AI summary
Disclosed are a light emission device comprising an LED element and a wavelength conversion section, the LED element emitting light of a specific wavelength and the wavelength conversion section converting the light emitted from the LED element to light of a specific wavelength, featured in that the wavelength conversion section is composed of a ceramic layer which has been formed employing, as a raw material, polysilazane containing a phosphor and inorganic fine particles with a particle size smaller than the phosphor.