Polyurethane Coated LED Leadframe for Uniform Insulation
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Solution Overview
Problem
Existing lighting assemblies with leadframes face challenges in achieving uniform electrically insulating coatings, particularly on complex three-dimensional structures, leading to potential short circuits and inadequate heat dissipation.
Innovation Solution
A polyurethane coating process with multiple cycles, including plasma pre-treatment and dipping, spraying, or brushing, is applied to ensure complete and uniform coverage of the leadframe, followed by a thermally conductive material overmolding for improved insulation and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common electrically insulating material like Teflon is used to coat the leadframe, then electrical insulation is provided, but uniform coverage on complicated three-dimensional structures is difficult to achieve
Solution Approach 1:
The patent changes the material parameter from conventional dielectric materials (Teflon, silicone, oxide, nitride) to polyurethane coating material, which has different physical and chemical properties that enable better flow and adhesion on complex three-dimensional surfaces, achieving uniform coverage while maintaining electrical insulation
Solution Approach 2:
The patent applies plasma treatment to the leadframe surface before coating to modify surface energy and improve wettability. This preliminary action ensures that the polyurethane coating can uniformly adhere to even sharp areas and complicated geometries of the leadframe
2Ease of manufacture
If sharp areas of the leadframe are not fully covered by electrically insulating material, then coating application is simplified, but short circuits occur
Solution Approach 1:
The patent uses polyurethane material with specific viscosity and adhesion properties that enable it to naturally flow into and completely cover sharp areas and embossments of the leadframe during the coating process, eliminating uncovered regions that could cause short circuits
Solution Approach 2:
Plasma treatment is applied beforehand to activate the leadframe surface, creating a high-energy surface that dramatically improves the wettability and adhesion of the polyurethane coating, ensuring complete coverage of all surfaces including sharp edges and corners
3Temperature
If high thermal conductivity material is molded around the leadframe, then heat dissipation is improved, but electrical insulation requirements become more critical
Solution Approach 1:
The patent creates a composite structure with polyurethane coating (electrical insulator) on the leadframe surface, overlaid with thermally conductive material for heat dissipation. This composite approach allows simultaneous achievement of electrical insulation and thermal management by combining materials with complementary properties
Solution Approach 2:
The patent applies different functional materials in different locations: polyurethane coating provides electrical insulation where needed on the leadframe surface, while thermally conductive material is applied in areas requiring heat dissipation. This localized functional differentiation optimizes both electrical and thermal performance
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
The solution provides reliable electrical insulation and enhanced heat dissipation capabilities without affecting light output, even on complex leadframe structures, using high thermal conductivity materials.
Implementation Method 1
a polyurethane coating arranged to electrically insulate the portion of the leadframe
Implementation Method 2
at least a portion of the polyurethane covered portion of the leadframe is further covered with a thermally conductive material
Data Source
AI summary
A lighting assembly is disclosed which includes a leadframe and at least one light-emitting diode (LED) element arranged on the leadframe. At least a portion of the leadframe is covered with a polyurethane coating arranged to electrically insulate the portion of the leadframe, and at least a portion of the polyurethane covered portion of the leadframe is further covered with a thermally conductive material. A method for manufacturing the lighting assembly is also disclosed.