Light-Emitting Apparatus with Glass-Covered Silver Reflector
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Solution Overview
Problem
Conventional light-emitting apparatuses using LTCC substrates suffer from light transmission or absorption, leading to decreased emission output, and metal reflecting layers deteriorate due to moisture or oxygen, resulting in reduced reflectance.
Innovation Solution
A light-emitting apparatus with a silver reflecting layer covered by a glass layer, which reflects light emitted by semiconductor devices towards the substrate, reducing loss and protecting the reflecting layer from deterioration, while using a sealing resin like dimethyl silicone or methyl rubber for added protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a metal reflecting layer is used to reflect light emitted by the LED chip, then light emission efficiency is improved, but the reflecting layer deteriorates due to moisture or oxygen, resulting in reduced reflectance
Solution Approach 1:
An inert gas filling (nitrogen or rare gas) is introduced as an intermediary between the metal reflecting layer and the external environment. This inert atmosphere acts as a protective barrier that prevents moisture and oxygen from reaching the metal reflecting layer, thereby maintaining its high reflectance and preventing deterioration while preserving its light reflection function
Solution Approach 2:
The patent creates an inert atmosphere environment by filling the encapsulation with nitrogen or rare gas. This inert environment excludes reactive gases like oxygen and moisture that would otherwise cause oxidation and deterioration of the metal reflecting layer, thus maintaining stable reflectance over time while preserving the light emission efficiency
2Temperature
If an LTCC substrate is used for heat dissipation, then thermal management is improved, but light transmission or absorption occurs, leading to decreased emission output
Solution Approach 1:
The encapsulation structure is segmented into distinct functional zones: a lower portion containing the LTCC substrate for heat dissipation, and an upper portion with high light transmittance for light emission. This segmentation allows each portion to optimize its specific function without compromising the other
Solution Approach 2:
Different portions of the encapsulation are assigned different optical and thermal properties. The lower portion near the heat-generating LED chip has high thermal conductivity (LTCC substrate) for heat dissipation, while the upper portion has high light transmittance for efficient light emission, creating local quality optimization throughout the structure
3Device complexity
If the reflecting layer is exposed to the environment, then manufacturing complexity is reduced, but the reflecting layer deteriorates and reflectance decreases
Solution Approach 1:
The patent creates an inert atmosphere environment by filling the encapsulation with nitrogen or rare gas. This inert environment excludes reactive gases like oxygen and moisture that would otherwise cause oxidation and deterioration of the metal reflecting layer, thus maintaining stable reflectance over time
Solution Approach 2:
The inert gas filling acts as an intermediary protective barrier between the metal reflecting layer and the external environment, preventing direct contact with harmful substances while maintaining a simple overall encapsulation structure
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
This configuration enhances light emission efficiency by minimizing loss and maintaining high reflectance, as the glass layer shields the silver reflecting layer from environmental factors, ensuring consistent performance.
Implementation Method 1
a light-reflecting layer, provided on the substrate, which reflects the light emitted by the at least one semiconductor device
Implementation Method 2
a covering layer which covers at least the light-reflecting layer and which transmits the light reflected by the light-reflecting layer
Implementation Method 3
the at least one semiconductor device and the connecting portions are sealed with a sealing resin so as to be covered
Implementation Method 4
a plurality of light-reflecting layers provided on the substrate and each having a different reflectance for a different wavelength range
Data Source
AI summary
A light-emitting apparatus of the present invention has (i) a semiconductor device which emits light toward a higher position than a substrate and (ii) a plurality of external connection terminals, and includes: a light-reflecting layer, provided on the substrate, which reflects the light emitted by the semiconductor device; and a covering layer which covers at least the light-reflecting layer and which transmits the light reflected by the light-reflecting layer. Further, the semiconductor device is provided on the covering layer, and is electrically connected to the external connection terminals via connecting portions, and the semiconductor device and the connecting portions are sealed with a sealing resin so as to be covered. Therefore, the light-emitting apparatus has increased efficiency with which light is taken out, and can prevent a reflecting layer from being altered, deteriorating, and decreasing in reflectance.