LED Chip Insert with Recessed Lead Frame for Thermal Management
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Solution Overview
Problem
High-power LEDs in vehicle lamps and headlights face challenges with thermal management due to insufficient heat conduction in conventional printed circuit boards, leading to potential light emission irregularities and increased costs with complex, expensive solutions like metal core PCBs or additional copper wire lines.
Innovation Solution
An LED chip insert for printed circuit boards, comprising a lead frame with conductive strings and an injection-molded frame, allows direct heat dissipation to a heat sink without costly components, using a recessed design that eliminates the need for external dams and simplifies the formation of reflective layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional printed circuit boards (FR-4) are used for mounting LEDs, then manufacturing cost is reduced, but heat dissipation capability is insufficient
Solution Approach 1:
The patent divides the thermal management function into separate components: the FR-4 PCB provides electrical connection and basic support, while a dedicated heat sink component handles thermal dissipation. This segmentation allows each component to be optimized independently - the PCB remains simple and inexpensive, while the heat sink is specifically designed for thermal management through copper pours, vias, and heat dissipation structures.
Solution Approach 2:
The patent introduces an intermediary thermal management system consisting of copper pours on the PCB surface, conductive adhesive layers, and heat sink structures. These intermediary elements act as thermal bridges between the LED chips and the external environment, enabling efficient heat transfer without requiring the entire PCB to be made of expensive thermally conductive materials like metal core PCBs.
2Temperature
If LED chips are placed directly on vias for heat dissipation, then thermal management is improved, but LED chip alignment and light emission quality deteriorate
Solution Approach 1:
The patent separates the electrical connection function (via holes) from the thermal management function (copper pours and heat sinks). LED chips are mounted on standard PCB areas with good mechanical support and alignment, while thermal pathways are created through separate copper pour structures that do not interfere with chip placement precision. This segmentation eliminates the conflict between via positioning and chip alignment.
Solution Approach 2:
The patent introduces copper pours as intermediary thermal pathways that extend from the PCB surface toward heat sink structures. These copper pours serve as thermal conduits without requiring LED chips to be directly positioned over vias, thereby maintaining chip alignment precision while still achieving efficient heat dissipation through the copper-rich pathways and external heat sinks.
3Temperature
If metal core PCBs or thermally conductive ceramics are used, then heat dissipation is improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent applies local quality by concentrating thermal management features only where needed - copper pours are created in specific regions beneath and around LED chips, and heat sink structures are positioned at thermal hotspots. The majority of the PCB remains simple FR-4 material, maintaining low overall complexity and cost while providing enhanced thermal management precisely where the LEDs generate heat.
Solution Approach 2:
The patent creates a composite thermal management system combining FR-4 PCB material with copper pours and conductive adhesive layers. This composite structure leverages the electrical and mechanical properties of FR-4 while adding thermal conductivity through copper and conductive adhesives only in the regions required for heat dissipation, avoiding the need for entirely expensive metal core PCBs or ceramics.
4Temperature
If additional copper wire lines are added for thermal management, then heat dissipation is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent merges the electrical connection function and thermal management function into unified copper trace structures. The same copper pathways that provide electrical connectivity to LED chips also serve as thermal conduction paths to heat sinks. This merging eliminates the need for separate copper wire lines or additional thermal management components, reducing manufacturing cost and complexity while achieving dual functionality.
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 enhances thermal management efficiency while reducing costs and maintaining light emission standards, allowing for effective heat dissipation and improved reliability without complex or expensive components.
Implementation Method 1
the LEDs are mounted on printed circuit boards (PCBs) directly, or by means of lead frames... heat can be transported to the back surface of the PCB, where it is connected to a heat sink
Data Source
AI summary
In an embodiment a LED chip insert for a printed circuit board includes a lead frame in which a number of electrically conductive strings with respective ends are formed by punching, the strings having support surfaces which are configured for mounting on the printed circuit board and which form a common plane, wherein the lead frame has a region formed as a recess with respect to the ends, an injection molded frame including an electrically insulating material and annularly surrounding a surface of the lead frame exposed within the region formed as the recess facing the ends of the strings, and thereby effecting an overall trough-like structure; and at least one LED chip which is placed in the region formed as the recess and has a first electrical contact terminal and a second electrical contact terminal, the first electrical contact terminal being electrically conductively connected to a first one of the strings and the second electrical contact terminal being electrically conductively connected to a second one of the strings.