Flexible LED Device with Etched Cavity for Thermal Management
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Solution Overview
Problem
Conventional light emitting semiconductor (LES) devices face challenges with heat dissipation and thermal management, particularly in high power applications, leading to material deterioration and limited use in low form factor designs due to thick packaging and inefficient heat management.
Innovation Solution
The integration of LESDs into a flexible polymeric dielectric substrate system with a thermally conductive layer, where the dielectric layer is etched to control thickness and create sloped cavities for enhanced heat dissipation and light reflection, allowing for efficient thermal management and reduced package thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional LESDs are used with thick packaging, then structural strength is maintained, but thermal dissipation efficiency deteriorates and form factor increases
Solution Approach 1:
The packaging structure is segmented into multiple functional layers: a flexible polymeric dielectric substrate, a thermally conductive layer, and an encapsulant layer. This segmentation allows each layer to perform its specific function optimally - the dielectric substrate provides mechanical support and electrical insulation, the thermally conductive layer dissipates heat, and the encapsulant protects the LESD, thereby improving thermal dissipation without requiring increased overall thickness
Solution Approach 2:
The patent applies local quality by creating a cavity in the dielectric substrate directly beneath the LESD and filling it with thermally conductive material. This concentrates the thermal management function specifically where heat is generated, providing efficient heat sinking at the critical location without adding thickness to the entire package structure
2Power
If high power LESDs operate at elevated temperatures, then light output is maintained, but material deterioration accelerates
Solution Approach 1:
The patent introduces a thermally conductive layer as an intermediary between the LESD and the external environment. This intermediary layer acts as a heat sink that absorbs excess thermal energy from the high-power LESD, preventing heat accumulation that would otherwise cause material deterioration, while allowing the LESD to maintain high light output power
Solution Approach 2:
The flexible polymeric dielectric substrate serves multiple functions simultaneously: it provides mechanical support, electrical insulation, and thermal management pathways. The substrate's inherent flexibility and thermal properties enable it to self-regulate temperature distribution, reducing thermal stress on materials without requiring additional active cooling components
3Temperature
If conventional submounts are used for LESD mounting, then thermal management is provided, but manufacturing cost increases
Solution Approach 1:
The patent merges the substrate and heat sink functions into a single integrated flexible polymeric dielectric substrate with embedded thermally conductive layers. This consolidation eliminates the need for separate conventional submounts and their associated mounting procedures, reducing both manufacturing complexity and cost while maintaining effective thermal management
Solution Approach 2:
The flexible dielectric substrate serves multiple universal functions: structural support, electrical insulation, thermal management, and mechanical flexibility. This multi-functionality replaces several discrete components (substrate, heat sink, mounting hardware) with a single universal element, simplifying manufacturing and reducing overall system cost
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 provides effective heat dissipation for high power LESDs, enabling their use in low form factor applications while reducing costs associated with conventional submounts and improving light management through reflective cavity walls.
Implementation Method 1
LESDs on one side of a dielectric layer are positioned near a thermally conductive layer or material on the opposite side of the dielectric layer
Implementation Method 2
Etching the dielectric layer may provide additional advantages by creating slanted side walls which can be coated with a reflecting material to provide enhanced light efficiency
Data Source
AI summary
Provided is a flexible light emitting semiconductor device, such as an LED device, that includes a flexible dielectric layer having first and second major surfaces with a conductive layer on the first major surface and at least one cavity in the first major surface with a conductive layer in the cavity that supports a light emitting semiconductor device. The conductive layer in the cavity is electrically isolated from the second major surface of the dielectric layer.