LED Lead Frame with Multi-Electrode Series Parallel Wiring
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Solution Overview
Problem
Typical light emitting diode (LED) packages have limited heat dissipation areas and are restricted to parallel electrical connections, which limits their efficiency and versatility.
Innovation Solution
A lead frame with a substrate, bonding electrodes, and a reflector made of thermally conductive materials, allowing for series or parallel electrical connections of LED chips and enhanced heat dissipation through a large bottom surface area and reflective materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If only two electrodes are provided in a typical LED package, then the structure is simple, but the electrical wiring versatility is limited to parallel connections only
Solution Approach 1:
The lead frame is designed with multiple electrodes (first electrode, second electrode, third electrode, and fourth electrode) that can serve different functions. The same lead frame structure enables both series and parallel electrical connections of LED chips, providing multi-functionality and versatility without requiring different structures for different connection types.
2Temperature
If a typical LED package uses a limited heat dissipation area, then the package structure is compact, but the heat dissipation efficiency is insufficient
Solution Approach 1:
The invention utilizes the bottom surface of the lead frame as an additional heat dissipation dimension. By making the bottom surface coplanar with the mounting surface and providing a large area (greater than the top surface area), heat can be dissipated through both the top mounting surface and the bottom surface simultaneously, effectively adding another dimension for heat dissipation.
3Area of stationary object
If the lead frame bottom surface is made coplanar with the mounting surface, then the heat dissipation area is increased, but the structural complexity increases
Solution Approach 1:
The invention merges the heat dissipation function with the structural support function by making the bottom surface of the lead frame coplanar with the mounting surface. This integration allows the same structural element to serve dual purposes: providing mechanical support and enabling heat dissipation, thereby reducing overall structural complexity while increasing heat dissipation area.
4Illumination intensity
If reflective materials are added to the lead frame, then the light extraction efficiency is enhanced, but the manufacturing complexity increases
Solution Approach 1:
The reflective cup structure is designed with asymmetric geometry, having a depth that is a specific fraction (0.05 to 0.2 times) of the lead frame's overall height. This asymmetric design optimizes light reflection and extraction efficiency while maintaining manufacturability through standard forming processes.
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 improves heat dissipation efficiency and allows for versatile electrical connections, reducing the risk of electrostatic discharge and enhancing light extraction efficiency while maintaining high thermal conductivity.
Implementation Method 1
a bonding electrode 20, a first connecting electrode 21, and a second connecting electrode 22... The bottom surface of the bonding electrode 20 occupies more than eighty percent of the entire area of the bottom surface of the lead frame 100, and heat generated from the first light emitting chip 41 and the second light emitting chip 42 is rapidly conducted to the bottom surface of the bonding electrode 20 for dissipation
Implementation Method 2
a reflector 30 located on the top surface 101 of the substrate 10... The reflector 30 and the substrate 10 are made of reflecting materials
Data Source
AI summary
A lead frame for an LED package includes a substrate and a bonding electrode, a first connecting electrode, and a second connecting electrode embedded in the substrate. A top surface of the bonding electrode includes a first bonding surface and a second bonding surface spaced from the first bonding surface. A top surface of the first connecting electrode includes separated first and second connecting surfaces. Top surfaces of the bonding electrode, the first connecting electrode, and the second connecting electrode are exposed, and support and electrically connect with light emitting chips. LED packages can be mounted on the lead frame and electrically connect with each other. The conductive layout of the lead frame further permits installation of a zener diode which can be connected to the LED packages in series or in parallel.