Polymeric Piezoelectric Pressure Sensor Thermal Stability
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Solution Overview
Problem
Polymeric piezoelectric materials used in pressure-sensing devices are sensitive to heat, leading to thermal deformation and changes in properties, which complicates the production process and results in misalignment of fine electrode patterns, increased thickness, and reduced optical transparency.
Innovation Solution
A pressure-sensing device is developed with a curable resin layer in contact with the polymeric piezoelectric element, which suppresses dimensional changes due to heat, eliminating the need for highly heat-resistant films and simplifying the production process, while maintaining transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If polymeric piezoelectric materials are used in pressure-sensing devices, then flexibility and environmental friendliness are improved, but thermal stability deteriorates causing deformation and property changes
Solution Approach 1:
The patent uses a composite structure consisting of a polymeric piezoelectric material layer and a heat-resistant resin layer. The heat-resistant resin layer (containing polysiloxane, polyimide, or polybenzoxazole) is applied to the polymeric piezoelectric material to create a composite structure that maintains the flexibility and piezoelectric properties of the polymer while adding thermal stability and resistance to deformation at elevated temperatures.
2Reliability
If extraction electrode is connected using ACF with intense heat, then electrical continuity is achieved, but polymeric piezoelectric material deforms and changes properties
Solution Approach 1:
The heat-resistant resin layer is applied to the polymeric piezoelectric material before the electrode connection process. This preliminary protective action ensures that when intense heat is applied during ACF bonding for electrical continuity, the polymeric piezoelectric material is already protected from thermal deformation and property changes.
Solution Approach 2:
The heat-resistant resin layer acts as an intermediary protective layer between the intense heat source (ACF bonding process) and the polymeric piezoelectric material. This intermediary layer absorbs or resists the thermal impact, preventing direct heat transfer to the piezoelectric material and maintaining its dimensional stability during the electrode connection process.
3Stability of the object's composition
If reinforcing plate is added to prevent deformation, then thermal stability is improved, but device complexity and thickness increase
Solution Approach 1:
Instead of using a rigid reinforcing plate that would increase device thickness and complexity, the patent employs a thin heat-resistant resin layer (coating film) that provides thermal protection while maintaining flexibility and minimizing added thickness. This thin film approach achieves thermal stability without the structural complexity of rigid plates.
4Manufacturing precision
If fine electrode pattern is formed, then device functionality is improved, but misalignment and damage risk increase under heat
Solution Approach 1:
The heat-resistant resin layer serves as a protective intermediary between the intense heat of the ACF bonding process and the fine electrode pattern on the polymeric piezoelectric material. This intermediary layer prevents direct thermal exposure that would cause misalignment or damage to the delicate electrode pattern, ensuring both precision and reliability.
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 results in a thinner, more transparent pressure-sensing device produced by a simpler process, with improved stability against thermal changes and reduced risk of electrode damage.
Implementation Method 1
a curable resin layer which is in contact with at least part of a surface of the polymeric piezoelectric element
Implementation Method 2
a polymeric piezoelectric element which has a piezoelectric constant d14 of 1 pC/N or more
Data Source
AI summary
A pressure-sensing device including a pressed component that has a contact surface to which pressure is applied by contact from a presser; a polymeric piezoelectric element that is disposed at an opposite side from the contact surface of the pressed component and that has a piezoelectric constant d14 of 1 pC/N or more as measured at 25° C. using a stress-charge method; a curable resin layer that includes at least one selected from the group consisting of cold-setting resins, thermosetting resins, and actinic radiation-curable resins and that is in contact with at least part of a surface of the polymeric piezoelectric element; and an electrode that is in contact with at least part of a surface of the polymeric piezoelectric element or of a surface of the curable resin layer.