LED Lead Frame Array Thermal Dissipation
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Solution Overview
Problem
The use of Printed Circuit Boards (PCBs) in Solid State Lighting applications is costly, adds assembly time, and impairs thermal dissipation due to high thermal resistance, leading to reduced reliability of LED components.
Innovation Solution
An LED lead frame assembly that includes a circuit strip assembly overmoulded with a plastic dam member, where the LED chip is potted and electrically coupled, allowing direct attachment to a lighting fixture without a PCB, enhancing thermal dissipation through a heat dissipation strip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PCB is used for LED array assembly, then electrical connection and structural support are achieved, but manufacturing cost increases and assembly time is extended
Solution Approach 1:
The patent extracts the LED components directly from the PCB substrate and mounts them onto a metal core circuit board with optimized thermal and electrical pathways. This eliminates the need for separate PCB assembly steps while maintaining electrical connection reliability through direct soldering to the metal core board's conductive traces.
Solution Approach 2:
The patent merges the electrical connection function and thermal management function into a single metal core circuit board structure. The metal core board simultaneously provides electrical pathways for LED connections and thermal pathways for heat dissipation, reducing the number of assembly steps and components needed.
2Reliability
If PCB is used for LED array assembly, then electrical connection is established, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive PCB materials and multi-layer circuit board structures with a cost-effective metal core circuit board design. The metal core board uses simpler construction with a copper or aluminum core layer providing both electrical and thermal pathways, significantly reducing material costs while maintaining connection reliability.
Solution Approach 2:
The patent changes the material parameters of the circuit board from standard PCB materials to metal core materials with superior electrical and thermal conductivity. This parameter change enables a single-board solution that performs multiple functions, reducing the need for additional components and assembly steps, thereby lowering overall manufacturing cost.
3Reliability
If standard PCB is used, then electrical connection is provided, but thermal dissipation is impaired due to high thermal resistance
Solution Approach 1:
The patent employs a composite metal core circuit board structure consisting of a metal core layer (copper or aluminum) bonded to insulating and conductive layers. This composite structure provides low thermal resistance pathways from the LED mounting area to the heat sink, while maintaining electrical isolation where needed. The metal core material has inherently higher thermal conductivity than standard PCB materials, enabling efficient heat dissipation.
Solution Approach 2:
The metal core circuit board acts as an intermediary between the LED components and the heat sink. It provides a thermal bridge that conducts heat away from the LED junctions to the heat sink, while also providing electrical pathways for current flow. This intermediary structure resolves the conflict between electrical insulation requirements and thermal conduction requirements.
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 solution reduces manufacturing costs and improves thermal efficiency and reliability by eliminating the need for PCBs and enabling direct attachment to a lighting fixture, thereby enhancing the performance of LED arrays in Solid State Lighting applications.
Implementation Method 1
The LED chip assembly is potted with a light-transmissive (e.g., clear) encapsulate
Implementation Method 2
enhancing thermal dissipation through a heat dissipation strip
Data Source
AI summary
An LED lead frame assembly includes a circuit strip assembly, a plastic dam member overmolded onto the circuit strip assembly and a LED chip assembly disposed in a pocket of the plastic dam member. The LED chip assembly is electrically coupled to the circuit strip assembly to power the LED chip assembly.