Semiconductor LED Lead Structure for Heat Escape in Resin Packages
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Solution Overview
Problem
Conventional semiconductor light emitting devices face challenges in size reduction and efficient heat dissipation due to limited thermal conductivity of the substrate, which hinders the enhancement of brightness.
Innovation Solution
A semiconductor light emitting device design featuring a semiconductor light source surrounded by a resin package with a lead that has a thin portion closer to the die bonding pad and a thick portion exposed outside the package, allowing for efficient heat dissipation and size reduction, while maintaining high brightness through proper mounting and light mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the current to flow through the LED chip is increased to enhance brightness, then the brightness is improved, but the heat generated from the LED chip increases
Solution Approach 1:
The patent extracts the heat dissipation function from the substrate by introducing a dedicated lead structure. The lead is configured with a first portion that contacts the LED chip and a second portion that extends to the exterior of the resin package, creating a separate heat dissipation pathway that is independent of the substrate's thermal conduction capabilities.
Solution Approach 2:
The lead acts as an intermediary heat transfer component between the LED chip and the exterior environment. It provides a direct thermal conduction path that bypasses the low thermal conductivity substrate, effectively mediating the heat transfer from the light source to the outside world.
2Device complexity
If the substrate material is used for heat dissipation, then the device structure is simple, but the thermal conductivity is relatively small leading to inefficient heat dissipation
Solution Approach 1:
The patent segments the heat dissipation function from the substrate structure by introducing a dedicated lead component. The lead is divided into a first portion for contacting the LED chip and a second portion for exterior exposure, creating a specialized heat dissipation pathway that is separate from the substrate's primary structural role.
Solution Approach 2:
The patent applies local quality by giving different portions of the lead different functions and configurations. The first portion of the lead is optimized for thermal contact with the LED chip, while the second portion is configured for efficient heat dissipation to the exterior, with each portion having properties tailored to its specific function.
3Volume of moving object
If the lead size is reduced for device miniaturization, then the device size is reduced, but the heat dissipation capability may be compromised
Solution Approach 1:
The patent utilizes dimensional optimization by configuring the lead to extend in the thickness direction of the resin package. This vertical arrangement allows the lead to achieve adequate heat dissipation surface area and thermal conduction path length without increasing the planar footprint of the device, effectively solving the heat dissipation problem in the thickness dimension rather than the lateral dimensions.
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 design achieves efficient heat escape and size reduction while maintaining high brightness by utilizing leads with distinct thickness portions to facilitate heat dissipation and ensure proper mounting of the semiconductor light source.
Implementation Method 1
the heat from the semiconductor light source efficiently escapes through the lead
Data Source
AI summary
A semiconductor light emitting device includes a semiconductor light source, a resin package surrounding the semiconductor light source, and a lead fixed to the resin package. The lead is provided with a die bonding pad for bonding the semiconductor light source, and with an exposed surface opposite to the die bonding pad The exposed surface is surrounded by the resin package in the in-plane direction of the exposed surface.