Flexible COB LED Arrays on Arcuate Heat Sinks
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Solution Overview
Problem
High power LEDs are typically rigid, limiting their application due to heat generation and thermal management issues, which restricts their use in flexible and compact lighting solutions requiring high lumen output.
Innovation Solution
The development of a flexible chip-on-board (COB) LED technology using a flexible substrate with conductive trace pads, where LED chips are wire-bonded and encapsulated with a silicone coating, allowing for flexible mounting on arcuate surfaces and integration with thermally conductive structures for efficient heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high power LEDs are assembled on rigid metal core printed circuit boards with ceramic or plastic heat sinks, then high lumen output and thermal management are achieved, but the structure becomes rigid and limits application flexibility
Solution Approach 1:
The patent replaces rigid PCB and heat sink assemblies with a flexible substrate that can be conformally mounted on various surfaces. The LED chips are directly mounted on this flexible substrate, eliminating the need for rigid MCPCB structures and enabling applications on curved or irregular surfaces while maintaining high lumen output capability
Solution Approach 2:
The patent separates the LED chip mounting function from the thermal management function by using distinct components: LED chips mounted on a flexible substrate for light output, and a separate flexible heat sink for thermal management. This segmentation allows independent optimization of each function and enables flexible configuration adapted to different application requirements
2Productivity
If multiple high power LEDs are placed in close configuration for high lumen output, then lighting efficiency is improved, but heat generation and thermal management complexity increase
Solution Approach 1:
The patent combines multiple LED chips and their respective thermal management functions into a single integrated flexible assembly. The flexible substrate integrates electrical interconnections and thermal pathways, allowing multiple LEDs to be closely spaced while sharing common thermal management infrastructure, thereby reducing overall system complexity
Solution Approach 2:
The flexible substrate acts as an intermediary between the LED chips and the flexible heat sink, providing both electrical interconnection and thermal conduction pathways. This intermediary structure simplifies thermal management by consolidating heat transfer routes and enabling uniform heat distribution across the LED array
3Temperature
If rigid PCB structures with thermal interface materials and fastening structures are used for thermal management, then heat dissipation is achieved, but the overall structure becomes bulky and rigid
Solution Approach 1:
The patent employs a flexible heat sink that can be conformally attached to the LED array, eliminating the need for bulky rigid heat sinks and complex mechanical fastening structures. The flexible substrate itself serves as a thin thermal interface, significantly reducing the overall volume of the LED assembly while maintaining effective heat dissipation
Solution Approach 2:
The patent extracts and eliminates unnecessary intermediate components such as rigid thermal interface materials and mechanical fastening structures from the traditional LED assembly. By using a flexible substrate that inherently provides both mechanical support and thermal conduction, the design removes redundant elements and reduces overall assembly volume
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 enables the creation of high-power, flexible LED arrays that can be applied to various lighting applications, providing uniform and efficient light distribution with reduced light loss and glare, while maintaining structural integrity and thermal management.
Implementation Method 1
LED chips are wire-bonded and encapsulated with a silicone coating
Implementation Method 2
integration with thermally conductive structures for efficient heat dissipation
Data Source
AI summary
A lighting device is disclosed having a plurality of LED chips mounted on a single planar flexible substrate, wherein the single planar flexible substrate is disposed in an arcuate orientation. A heat sink having an arcuate surface shaped to approximate the arcuate orientation of the flexible substrate is coupled to the flexible substrate between complementary arcuate surfaces. A luminescent coating is disposed about a top surface of the arcuate single planar flexible substrate.