Resin Package Recess for Light Extraction and Heat Dissipation
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Solution Overview
Problem
Conventional light emitting devices face challenges in heat dissipation and light extraction efficiency, particularly due to the expansion of light reflecting members near the light emitting elements, which can lead to reduced reliability and performance.
Innovation Solution
The design incorporates a resin package with a recess and a groove on the first lead, allowing for increased heat dissipation paths while reducing the width of the heat transfer area, and a light reflecting member positioned between the recess lateral surfaces and the groove, preventing the expansion of the light reflecting member and enhancing light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light reflecting member is disposed near the light emitting element to improve light extraction efficiency, then light extraction efficiency is improved, but the light reflecting member expands due to heat from the light emitting element, causing reliability degradation
Solution Approach 1:
The resin package is divided into a recess portion and a flat portion, creating distinct functional zones. The light reflecting member is specifically disposed in the recess portion, separating it from the flat portion where heat accumulation occurs, thus preventing expansion while maintaining light extraction efficiency
Solution Approach 2:
The recess portion provides a localized environment with different thermal and optical properties compared to the flat portion. This local structural modification allows the light reflecting member to be positioned optimally for light extraction while being protected from harmful heat effects
2Temperature
If heat dissipation paths are increased to improve heat dissipation, then heat dissipation is improved, but the width of the heat transfer area must be reduced
Solution Approach 1:
The invention transitions from a two-dimensional heat dissipation approach to a three-dimensional structure by creating a recess portion. This vertical dimension allows heat to dissipate through multiple paths (laterally along the recess walls and vertically through the structure) without requiring a reduction in the horizontal heat transfer area width
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 improves heat dissipation, prevents the creeping of light reflecting members, and achieves high reliability and light extraction efficiency in light emitting devices.
Implementation Method 1
a light reflecting member disposed on the recess bottom surface between the recess lateral surface and the light emitting element in a lateral direction
Implementation Method 2
increased heat dissipation paths while reducing the width of the heat transfer area
Data Source
AI summary
A light emitting device includes a resin package having a recess defined by a recess bottom surface and a recess lateral surface. The resin package includes a first lead including a first lead lower surface, a first lead upper surface, and an end portion. The light emitting element is mounted on the first lead upper surface opposite to the first lead lower surface. The light reflecting member is disposed on the recess bottom surface between the recess lateral surface and the light emitting element in a lateral direction. The end portion is provided between the first lead lower surface and the light reflecting member in the lateral direction. The end portion has a cross-sectional area viewed in the lateral direction which is smaller than a cross-sectional area of the first lead between the first lead lower surface and the first lead upper surface viewed in the lateral direction.