PLCC LED Package Multi-Level Leadframe Heat Dissipation
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Solution Overview
Problem
Current PLCC package designs for high-power surface mount LEDs require increased size or additional metal for effective heat dissipation, leading to higher manufacturing costs.
Innovation Solution
A compact PLCC package design utilizing a first and second leadframe with a multi-level configuration, where the second leadframe's surface is positioned higher than the first, along with wing-like extensions and a reflector cup for efficient heat dissipation without increasing package size or adding metal, and a method for making this package by attaching leadframes to a structural body and electrically connecting the LED die.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the package size is increased to handle increased heat, then heat dissipation is improved, but the compactness of the LED package deteriorates
Solution Approach 1:
The patent utilizes a multi-level vertical configuration where the second leadframe is positioned at a higher level than the first leadframe. This vertical stacking approach allows heat dissipation structures to be arranged in the vertical dimension rather than requiring horizontal expansion, thereby improving heat dissipation capability while maintaining a compact package footprint.
2Temperature
If an additional piece of metal is added to form a heat sink, then heat dissipation is improved, but manufacturing cost increases
Solution Approach 1:
The second leadframe serves multiple functions: it provides electrical connection for the LED die and simultaneously acts as a heat dissipation structure. By integrating these two functions into a single component, the patent eliminates the need for an additional separate metal heat sink piece, thereby reducing manufacturing complexity and cost while maintaining effective heat dissipation.
3Illumination intensity
If the driving current is increased to produce brighter LEDs, then illumination intensity is improved, but heat generated by the die increases
Solution Approach 1:
The second leadframe positioned at a higher level acts as an intermediary heat dissipation path between the LED die and the external environment. This intermediate structure provides an additional thermal conduction pathway that facilitates more efficient heat removal from the die, enabling the LED to operate at higher currents for increased brightness without excessive temperature rise.
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 effectively dissipates heat generated by high-power LEDs, maintaining optimal operating temperature and brightness without increasing package size or manufacturing costs.
Implementation Method 1
an important function of an LED package is heat dissipation to maintain an optimal operating temperature for the LED die
Data Source
AI summary
A light emitting device package and method for making the package utilizes a first leadframe having a first surface and a second leadframe having a second surface that are relatively positioned such that the second surface is at a higher level than the first surface. The light emitting device package includes a light source, e.g., a light emitting diode die, which is mounted on the first surface of the first leadframe and electrically connected to the second surface of the second leadframe.