Flexible LED Substrate Thermal Dissipation via Via Extraction
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Solution Overview
Problem
Conventional light emitting semiconductor (LES) devices face challenges with heat dissipation and thermal management, particularly when used in high power applications, leading to material deterioration and limited use in low form factor designs due to excessive heat buildup and thick package structures.
Innovation Solution
The integration of LESDs into a flexible polymeric dielectric substrate with controlled thickness of the insulator material or complete removal of the insulator to establish direct thermal contact with thermally conductive layers, utilizing cavities or vias for enhanced heat dissipation, and the use of thermally conductive materials within these structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional LES devices are used with thick package structures, then mechanical strength and protection are improved, but thermal dissipation deteriorates and form factor flexibility is limited
Solution Approach 1:
The patent transitions from conventional thick z-axis packaging to a thin x-y plane mounted structure. LESDs are mounted directly onto a flexible substrate in a planar configuration, eliminating the need for thick vertical packaging while maintaining mechanical protection through the flexible substrate and encapsulants.
Solution Approach 2:
The patent employs a flexible substrate as the mounting platform for LESDs, replacing rigid thick packages with thin flexible structures. This flexible substrate provides mechanical support and protection while enabling thermal dissipation through direct contact with thermally conductive materials.
2Reliability
If insulator material thickness is increased to protect LESDs, then electrical insulation is improved, but thermal contact with thermally conductive layers deteriorates
Solution Approach 1:
The patent applies thin insulator material selectively in regions where electrical insulation is needed, while maintaining direct thermal contact between LESDs and thermally conductive layers in heat dissipation paths. This localized approach to insulation thickness optimizes both electrical protection and thermal management.
Solution Approach 2:
The patent removes or minimizes insulator material between LESDs and thermally conductive layers, extracting only the minimum necessary insulation to maintain electrical isolation while maximizing thermal contact. This selective removal enables direct thermal pathways without compromising electrical safety.
3Reliability
If conventional thick packaging is used, then device protection is improved, but adaptability to low form factor applications deteriorates
Solution Approach 1:
The patent reconfigures device protection from a vertical z-axis orientation to a horizontal x-y plane orientation. LESDs are mounted directly on the flexible substrate surface with encapsulants providing protection from above, enabling thin-profile applications while maintaining comprehensive device protection.
Solution Approach 2:
The patent uses a flexible substrate as both the mounting platform and protective structure, replacing conventional rigid packages. This flexible thin-film structure provides mechanical protection and environmental sealing while enabling adaptation to low form factor and bendable applications.
4Power
If high power LESDs are used to increase output, then power capability is improved, but heat generation and thermal management complexity increase
Solution Approach 1:
The patent extracts and removes insulator material between LESDs and thermally conductive layers, creating direct thermal pathways that efficiently conduct heat away from high power devices. This extraction of unnecessary insulating material simplifies the thermal management path while handling high power heat generation.
Solution Approach 2:
The patent makes the flexible substrate serve multiple functions: mechanical support, electrical insulation, thermal conduction pathway, and structural protection. This multi-functional design simplifies thermal management by integrating heat dissipation into the substrate itself rather than requiring separate complex thermal management systems.
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 provides excellent thermal dissipation in the x-y direction, reduces thermal resistance, allows for flexible and bendable designs, minimizes yield loss in packaging, and offers a cost-effective solution for high power LESD constructions by enabling efficient heat management and eliminating the need for conventional submounts.
Implementation Method 1
heat dissipation can be managed by integrating the LESDs into a system having a flexible polymeric dielectric substrate... LESDs are positioned so they are in close or direct thermal contact with thermally conductive layers... excellent thermal dissipation in the x-y direction
Data Source
AI summary
A flexible polymeric dielectric layer has first and second major surfaces. The first major surface has a conductive layer thereon. The dielectric layer has at least one via extending from the second major surface to the first major surface. The conductive layer includes electrically separated first and second portions configured to support and electrically connect a light emitting semi-conductor device to the conductive layer.