Dielectric Ink Composition for Stretchable Electronics
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Solution Overview
Problem
Current dielectric inks are not suitable for stretchable electronic devices due to issues such as incompatibility with conductive layers, inadequate adhesion, and poor mechanical properties, leading to instability and inefficiency in forming complex electronic devices with multiple layers.
Innovation Solution
A flexible dielectric ink composition comprising a dielectric material in the form of powder, flakes, or resin, combined with organic binders and UV-curable or thermally curable initiators, which can be screen-printed and cured at low temperatures, providing excellent adhesion and stretchability up to 150% without loss of electrical continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional dielectric inks are used, then manufacturing process is simple, but adhesion to substrate and conductive layers is inadequate
Solution Approach 1:
The dielectric ink uses a composite binder system combining polyester resin and acrylic polymer, with polyester providing adhesion to conductive layers and acrylic providing flexibility and stretchability. This composite approach resolves the contradiction by achieving both strong adhesion and mechanical flexibility that single-material binders cannot provide.
Solution Approach 2:
The ink formulation adjusts the glass transition temperature (Tg) of the binder system to be below the substrate forming temperature, enabling the dielectric layer to remain flexible during high-temperature thermoforming processes. This parameter adjustment allows the material to maintain adhesion while accommodating thermal processing requirements.
2Adaptability or versatility
If rigid dielectric materials are used, then electrical insulating properties are excellent, but stretchability and flexibility are poor
Solution Approach 1:
The dielectric ink forms a thin film structure that inherently provides flexibility and stretchability. The film morphology, combined with the polymer binder system, allows the dielectric layer to stretch up to 150% without cracking, maintaining both mechanical flexibility and electrical insulating properties simultaneously.
Solution Approach 2:
The organic binder system acts as an intermediary between the rigid dielectric filler particles and the flexible substrate, transferring mechanical deformation from the substrate to the dielectric layer without causing failure. This mediator enables the rigid dielectric material to accommodate flexible substrate deformation while maintaining electrical continuity.
3Reliability
If high-temperature curing is used, then dielectric properties are improved, but substrate deformation and cracking occur
Solution Approach 1:
The binder system's glass transition temperature is engineered to be below the substrate forming temperature, allowing the dielectric layer to remain in a rubbery, flexible state during high-temperature thermoforming. This parameter control enables curing at temperatures that improve dielectric properties without causing substrate deformation or cracking.
4Reliability
If dielectric layer is made thick, then electrical insulation is improved, but adhesion and flexibility are reduced
Solution Approach 1:
The ink formulation and application process create a thin film dielectric layer that provides sufficient electrical insulation through optimized filler loading and particle packing, rather than relying on thickness. This thin film structure maintains flexibility and adhesion while achieving the required electrical insulating properties.
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 ink composition achieves high resistivity, improved thermal stability, and reliability, enabling the formation of stretchable electronic circuits with enhanced mechanical properties and optical transparency, suitable for complex device manufacturing without cracking or delamination.
Implementation Method 1
UV-curable or thermally curable initiators
Implementation Method 2
UV-curable or thermally curable initiators
Implementation Method 3
A dielectric material (otherwise known as a 'dielectric') is an electrical insulator that is capable of being polarized by an applied electric field
Data Source
AI summary
The present invention relates to flexible and stretchable UV and thermally curable dielectric ink compositions that can be thermo or vacuum formed. The flexible ink can form a stretchable dielectric coating having excellent adhesion. The dielectric ink compositions can be applied on a circuit board, such as a paper-phenolic resin board, plastic board (PMMA, PET or the like) or a glass-epoxy resin board, by screen printing or the like, followed by heat/UV curing. The compositions are suitable for use in applications such as a capacitive touch, in-mold forming, creating cross over insulation layers, and manufacturing electronic circuitry and devices.