LED Package Heat Dissipation via Lead Frame Integration
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Solution Overview
Problem
Current methods for manufacturing LED sticks, strings, or straws face challenges such as low yields due to stress from chip-shooter placement and wire bonding, and difficulties in applying yellow phosphor coatings to elongated structures, which affect light output and lifespan.
Innovation Solution
The method involves placing LED die chips on adjoining metal frames, forming an electrical chain, and encapsulating them within a solid enclosure with electrical connections for power, using a sapphire or sapphire-like material, and applying a heat-activated phosphor coating to ensure efficient heat dissipation and uniform light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual packaged LEDs are placed in the stick using chip-shooter and wire bonding, then electrical connections are established, but significant stresses are caused to the package resulting in low yields
Solution Approach 1:
The patent merges the LED chip placement and electrical connection processes by integrating the LED chips directly onto the lead frame structure during molding, eliminating the need for separate chip-shooter placement and wire bonding operations. This consolidation removes the mechanical stressors that caused package failure and low yields.
Solution Approach 2:
The patent extracts the problematic intermediate steps (chip-shooter placement and wire bonding) from the manufacturing process. By removing these stress-inducing operations and directly molding LEDs onto the lead frame, the package stress is eliminated while maintaining electrical connectivity.
2Temperature
If LED chips are placed on a separate device for heat dissipation, then heat is effectively removed, but the structure becomes complex and manufacturing yield decreases
Solution Approach 1:
The patent combines the heat dissipation function with the electrical connection structure by integrating the lead frame as both the electrical conductor and the heat sink. This eliminates the need for separate heat dissipation devices and reduces manufacturing complexity, thereby improving yield.
Solution Approach 2:
The lead frame is designed to serve multiple functions simultaneously: providing electrical connections, structural support, and heat dissipation. This multi-functionality simplifies the overall structure and manufacturing process while maintaining effective thermal management.
3Illumination intensity
If yellow phosphor coating is applied to elongated LED string structures, then white light emission is achieved, but the coating is hard to apply uniformly
Solution Approach 1:
The patent applies the yellow phosphor coating to the lead frame structure before the LEDs are attached. This preliminary action allows for uniform coating application on a simpler, more accessible surface, avoiding the difficulty of coating elongated LED string structures after assembly.
Solution Approach 2:
Instead of coating the finished LED string structure, the patent inverts the process by coating the lead frame first, then attaching the LEDs. This reversal makes the coating process much more manageable and achieves uniform phosphor distribution.
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 approach enhances yield and light output by reducing heat stress and facilitating even phosphor coating, allowing for higher power consumption and longer lifespan of LED packages, similar to incandescent bulbs.
Implementation Method 1
applying a heat-activated phosphor coating to ensure efficient heat dissipation and uniform light emission
Implementation Method 2
using a sapphire or sapphire-like material, and applying a heat-activated phosphor coating to ensure efficient heat dissipation
Data Source
AI summary
The present invention relates to a new method, system and apparatus for light emitting diode (LED) packages. An object of the present invention is to provide an LED package having reduced components, a superior heat dissipation property and a compact structure, does not largely restrict use of conventional equipment for its manufacture, and is compatible with implementation within present illumination devices packaging.