Single-Layer LED Carrier with Metal Core and Micro-Vias
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Solution Overview
Problem
High-power LED arrays in applications like automotive lighting face thermal insulation issues due to dielectric layers in multi-layer PCBs, leading to reduced LED lifetime and the need for larger, heavier collimating elements to manage heat and spacing, resulting in a bulky lighting arrangement.
Innovation Solution
A single-layer carrier with a metal core and dielectric layer, utilizing micro-vias to connect LED cathodes directly to the metal core for efficient thermal dissipation and compact packing of LEDs, eliminating the need for conductive tracks and allowing close proximity of LEDs without a collimating optical element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-layer PCB with dielectric layers is used to route circuits, then electrical insulation between routing levels is achieved, but thermal insulation prevents effective heat transport from LEDs
Solution Approach 1:
The invention divides the carrier into a single-layer structure with separate functional zones: a mounting surface for LEDs, a dielectric layer for electrical insulation, and a metal core for thermal management. This segmentation allows each layer to perform its specific function without the thermal insulation problems of multi-layer PCBs.
Solution Approach 2:
The invention extracts the thermal management function from the dielectric layer by introducing a dedicated metal core layer. The metal core is thermally coupled to the mounting surface through thermal vias, creating a separate thermal conduction path that does not interfere with the electrical insulation function of the dielectric layer.
2Duration of action of stationary object
If LEDs are spaced apart to allow heat dissipation, then LED lifetime is improved, but the matrix size becomes large and requires larger collimating elements
Solution Approach 1:
The metal core acts as an intermediary thermal management component that enables close LED spacing. By providing a high-thermal-conductivity path from the mounting surface to the heat sink, the metal core allows LEDs to be densely packed while maintaining effective heat dissipation, thus preserving LED lifetime without increasing matrix size.
3Productivity
If a single-layer carrier with metal core and micro-vias is used, then thermal dissipation is improved and LED packing density increases, but manufacturing complexity arises
Solution Approach 1:
The invention moves thermal conduction paths from the planar routing layer to the vertical dimension by using micro-vias through the dielectric layer to connect the mounting surface to the metal core. This dimensional transition enables efficient thermal management without complicating the planar LED layout and mounting 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
This approach enables a compact, efficient, and cost-effective LED lighting arrangement with improved thermal management, allowing for direct projection systems without the need for bundling optical elements, enhancing the packing density and reducing the overall size and weight of the lighting unit.
Implementation Method 1
A disadvantage of the prior art arrangements is that any heat spreader, heat sink or thermal block must be arranged underneath the PCB, but the dielectric layers that separate any two routing levels of the PCB are also thermally insulating.
Implementation Method 2
at least one micro-via extending through the dielectric layer of the single-layer carrier and arranged to electrically connect the final cathode of an LED string to the metal core of the single-layer carrier
Data Source
AI summary
The invention describes an LED lighting arrangement comprising a single-layer carrier comprising a mounting surface, a metal core, and a dielectric layer between the mounting surface and the metal core; at least one LED string comprising a plurality of series-connected LED die packages mounted on the mounting surface, wherein the LED die packages of a string are arranged in a two-dimensional array comprising at least two rows; and at least one micro-via extending through the dielectric layer of the single-layer carrier and arranged to electrically connect the final cathode of an LED string to the metal core of the single-layer carrier. The invention further describes a lighting unit; and a method of manufacturing an LED lighting arrangement.