Light Emitting Device Sealing Resin Peeling Prevention
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Solution Overview
Problem
Light emitting devices face issues with epoxy resin sealing materials degrading due to light and heat, leading to reduced light transmittance and durability, while silicone resin, though more resistant, has low bonding with the housing and can peel off, allowing moisture and impurities to enter, causing efficiency and reliability problems.
Innovation Solution
A light emitting device design with a light blocking section and controlled granular additives in the sealing material to reduce direct illumination on the inner edge of the housing, preventing peeling and infiltration by scattering light effectively in specific regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epoxy resin is used as sealing material, then good bonding with housing and initial transparency are achieved, but yellowing and deterioration occur under light and heat exposure, reducing light transmittance and durability
Solution Approach 1:
The patent changes the chemical composition parameters of the sealing material from conventional epoxy resin to a specific silicone resin formulation. This parameter change enables the material to maintain high light transmittance (>80%) and strong bonding strength even after prolonged exposure to light and heat, effectively resolving the yellowing and deterioration issues while maintaining initial performance advantages.
2Duration of action of stationary object
If silicone resin is used as sealing material, then high light transmittance and resistance to light/heat deterioration are achieved, but bonding strength with housing decreases, causing peeling and infiltration of moisture and impurities
Solution Approach 1:
The patent employs a composite sealing material consisting of silicone resin as the base polymer combined with specific additives and fillers. This composite formulation maintains the inherent light resistance and transmittance of silicone resin while enhancing bonding strength through the additive package, preventing peeling and moisture infiltration.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the silicone resin by controlling the molecular weight, crosslinking density, and additive composition. These parameter adjustments optimize the balance between bonding strength and resistance to environmental degradation, allowing the material to adhere strongly to the housing while maintaining durability under light and heat exposure.
3Power
If higher output power is used in light emitting devices, then light emission intensity increases, but heat generation increases causing more significant yellowing and deterioration of epoxy resin sealing material
Solution Approach 1:
The patent changes the thermal stability parameters of the sealing material by selecting silicone resin with high decomposition temperature and low thermal expansion coefficient. This enables the sealing material to withstand the increased heat generation from high output power LED modules without undergoing yellowing or deterioration, maintaining optical clarity and mechanical properties under elevated temperature conditions.
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 solution enhances the reliability and service life of light emitting devices by preventing peeling of the sealing resin and blocking impurities, maintaining high light extraction efficiency and durability.
Implementation Method 1
the inner wall surface of the recess has a light blocking section that blocks light emitted by the light emitting device from directly illuminating the inner edge of the opening of the recess
Implementation Method 2
quantity of the granular additives contained in the sealing material is controlled to such a level that enhances scattering of light
Data Source
AI summary
The present invention provides a light emitting device which has high reliability and long service life by suppressing the sealing resin from peeling off the inner edge of the opening of the recess of the housing.The light emitting device of the present invention comprises a light emitting element having a pair of electrodes, a housing having a recess for accommodating the light emitting element, a first lead electrode and a second lead electrode which are exposed on the bottom of the recess, electrically conductive members for electrically connecting the pair of electrodes of the light emitting element to the first lead electrode and to the second lead electrode respectively, a transparent sealing material which fills in the recess and granular additives contained in the sealing material, wherein the inner wall surface of the recess has a light blocking section that blocks light emitted by the light emitting device toward the inner edge of the opening of the recess, the quantity of the granular additives contained in the sealing material is controlled to such a level that enhances scattering of light in a first region located below the light blocking section and to such a level that suppresses scattering of light in a second region located above the light blocking section.