Phosphor Glass Coating for Moisture Resistance
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Solution Overview
Problem
Phosphors excited by blue light have low moisture resistance, making it difficult for light source devices to pass reliability tests under conditions of high temperature and humidity, leading to deterioration in performance over time.
Innovation Solution
A light emitting composition where the surface of the phosphor is coated with a glass layer containing silicon and oxygen, with exposed regions made discrete by the glass layer, improving moisture resistance and maintaining light intensity over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a phosphor excited by blue light is used in a light source device, then the drive circuit can be simplified and deterioration of peripheral members can be suppressed, but the moisture resistance is low and the characteristics are deteriorated by moisture contained in the air
Solution Approach 1:
An intermediate substance (encapsulating resin or coating layer) is introduced between the phosphor particles and the external environment to prevent moisture from reaching the phosphor surface. This mediator layer allows the phosphor to maintain its light-emitting properties while being protected from moisture-induced degradation.
Solution Approach 2:
The phosphor is combined with protective materials such as encapsulating resins or coating materials to form a composite structure. This composite approach maintains the phosphor's optical properties while adding moisture resistance through the protective material layer.
2Reliability
If glass is deposited on the surface of the phosphor to improve moisture resistance, then the moisture resistance may be improved, but the deposited glass may be discrete and the moisture resistance is possibly reduced
Solution Approach 1:
A continuous thin film coating is applied to the phosphor surface to provide uniform moisture protection. This thin film approach ensures complete coverage without the discrete particle structure that would leave gaps, creating a seamless protective barrier while maintaining manufacturing feasibility.
3Adaptability or versatility
If the phosphor is used under high temperature and humidity conditions, then the light source device can operate in stringent environments, but the emitted light intensity decreases by about 60% after 173 hours
Solution Approach 1:
Protective measures (encapsulation or coating) are applied to the phosphor before it is exposed to harsh environmental conditions. This beforehand protection creates a buffer that prevents moisture and temperature from directly affecting the phosphor, thereby maintaining light intensity over extended periods in stringent environments.
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 discrete glass layer coating significantly enhances the moisture resistance of the phosphor, ensuring the light source device maintains performance and reliability even under stringent conditions, such as high temperature and humidity, for extended periods.
Implementation Method 1
the surface of the phosphor is coated with a glass layer containing at least silicon (Si) and oxygen (O)
Implementation Method 2
a phosphor to be excited by blue light emitted from a blue light source
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The present invention provides a light emitting composition having a phosphor, including a glass layer containing at least silicon (Si) and oxygen (O) formed on the surface of the phosphor. Exposed regions of the phosphor are made discrete by the glass layer.