Adhesive Circuit Patterning With Thermal Film Joint Protection
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Solution Overview
Problem
Existing methods for protecting printed circuit traces and adhesive bonded joints in flexible electronics are costly, have limited supplier chains, are not suitable for high-density circuitry or miniaturization, require additional waterproofing, and suffer from low interconnect reliability and printing repeatability.
Innovation Solution
A method involving the use of thermoplastic polyurethane hot melt films to reinforce and protect printed circuit traces and adhesive bonded joints through a single heat curing process, which includes drying, printing a circuit pattern, attaching surface mounted devices, and placing the film on a stretchable substrate to form an adhesive circuit pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional encapsulation processes and lamination processes are used to protect circuit traces and adhesive bonded joints, then protection from mechanical strain is improved, but device complexity and manufacturing cost increase due to multiple different techniques being needed
Solution Approach 1:
The patent combines encapsulation, lamination, and adhesive bonding functions into a single thermoplastic adhesive film layer. This single film performs multiple protective functions simultaneously, eliminating the need for separate encapsulation and lamination processes, thereby reducing device complexity while maintaining reliability.
Solution Approach 2:
The thermoplastic adhesive film serves multiple functions: it acts as an adhesive bonding agent for mounting devices, provides encapsulation protection for circuit traces, and offers lamination protection against mechanical strain. This multi-functional approach replaces multiple specialized components with a single universal protective layer.
2Manufacturing precision
If circuit embroidery, flocking, or direct conductive ink screen printing is used, then circuit patterning is achieved, but manufacturing cost increases due to high raw material cost and high capital expenditure
Solution Approach 1:
The patent uses a thermoplastic adhesive film that can be easily printed with conductive ink as a disposable or single-use substrate for circuit patterning. This approach eliminates the need for expensive specialized materials like conductive yarns or sub-nanometal particle materials, significantly reducing raw material costs while maintaining circuit patterning capability.
Solution Approach 2:
The patent changes the substrate material from expensive specialized materials (conductive yarn, nanoparticle-coated fabrics) to a conventional thermoplastic adhesive film that can be printed with standard conductive inks. This parameter change in material selection reduces both material cost and capital expenditure for specialized equipment.
3Manufacturing precision
If circuit embroidery or flocking is used, then circuit patterning is achieved, but additional waterproofing process is required due to limited washable cycle
Solution Approach 1:
The patent creates a homogeneous sealed structure where the thermoplastic adhesive film is melted to envelop and seal the circuit traces, adhesive bonds, and device interconnects. This homogeneous encapsulation provides inherent waterproofing and washability without requiring additional waterproofing coatings or processes, as the entire structure is sealed within the thermoplastic matrix.
4Manufacturing precision
If circuit embroidery, flocking, or direct conductive ink screen printing is used, then circuit patterning is achieved, but interconnect reliability on surface mounted device packages decreases
Solution Approach 1:
The patent uses the thermoplastic adhesive film to provide beforehand cushioning and mechanical protection to the adhesive bonded joints and device interconnects. By enveloping these critical connections within the melted thermoplastic matrix, the structure gains enhanced mechanical strength and strain relief, significantly improving interconnect reliability on surface mounted device packages.
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 method enhances the robustness and environmental protection of flexible electronics by providing a water-resistant, easy-to-clean surface with improved interconnect reliability and suitability for high-density circuitry and miniaturization.
Implementation Method 1
The thermal adhesive film is melted on the assembled printed circuit and the stretchable substrate to protect and reinforce joint bonds and the circuit pattern
Implementation Method 2
One or more surface mounted device(s) are attached to a cured printed circuit
Data Source
AI summary
Disclosed are processes and materials for adhesive circuit patterning which strengthen and protect printed circuit traces and adhesive bonded joints of surface mounted devices in flexible or stretchable electronics in a single process. A method for adhesive circuit pattering include deposing a circuit pattern on a thermal adhesive film. One or more surface mounted device(s) are attached to a cured printed circuit to form an assembled printed circuit. The assembled printed circuit may be placed on a stretchable substrate. The thermal adhesive film is melted on the assembled printed circuit and the stretchable substrate to protect and reinforce joint bonds and the circuit pattern of the assembled circuit pattern and attach the assembled printed circuit to the stretchable fabric in one melting or curing step.