Side View LED Package Heat Dissipation via Exposed Lead Frame
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Solution Overview
Problem
Conventional side view type LED packages face challenges with heat dissipation, limiting their ability to handle currents equal to or greater than their rated values due to restricted heat dissipation paths, which restricts luminous intensity and usage.
Innovation Solution
The solution involves exposing a portion of the lead frame outside the package body to serve as an additional heat dissipation path, with upper and lower legs extending from the inner leads to create separate heat dissipation paths, allowing for improved heat dissipation without increasing the package size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat dissipation paths are limited only to outer leads, then the package structure remains simple, but heat dissipation capability is insufficient
Solution Approach 1:
The lead frame is designed to serve multiple functions: the outer leads provide both electrical connection and heat dissipation, while additional heat dissipation legs extend from inner leads to provide dedicated thermal pathways. This multi-functional design improves heat dissipation capability without requiring completely separate thermal management components.
Solution Approach 2:
The heat dissipation function is segmented into multiple independent pathways: outer leads and separate heat dissipation legs extending from different inner leads. This segmentation allows heat to be distributed through multiple parallel paths, improving overall heat dissipation capability while maintaining structural organization.
2Illumination intensity
If current is increased to improve luminous intensity, then light output increases, but heat dissipation becomes insufficient
Solution Approach 1:
Heat dissipation is extended into a new spatial dimension by adding vertical heat dissipation legs that extend upward from inner leads. This three-dimensional heat dissipation structure provides additional thermal pathways without increasing the horizontal footprint of the package, enabling better heat management for higher current operation.
3Temperature
If heat sink is installed to improve heat dissipation, then heat dissipation capability improves, but package size increases
Solution Approach 1:
The heat dissipation function is merged with the existing lead frame structure. Heat dissipation legs are integrated into the lead frame as extensions from inner leads, combining electrical connection and thermal management functions into a single unified structure. This eliminates the need for separate heat sink components and keeps the package compact.
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 enables the side view type LED package to handle higher currents, reducing junction temperature and thermal resistance, thereby enhancing luminance and allowing for more effective heat dissipation even without a heat sink.
Implementation Method 1
heat dissipation paths are limited only to outer leads which are portions of the lead frames for forming electrical contact surfaces
Implementation Method 2
a light source system using a light emitting diode chip (hereinafter, referred to as LED chip)
Data Source
AI summary
In a side view type light emitting diode (LED) package, a lead frame portion and lead frame electrical contact portions are exposed outside a package body to serve as an additional heat dissipation path. The side view type LED package includes an LED chip, a package body having a side surface with an opening for receiving the LED chip, and lead frames for applying a current to the LED chip. The lead frames include inner leads electrically connected to the LED chip within the package body; electrical contact lower legs extending from the inner leads to a lower portion of the package body and exposed outside the package body in the vicinity of a lower surface of the package body perpendicular to the side surface; and a heat dissipation means extending, separately from the electrical contact lower legs, from at least one of the inner leads outside the package body.