Capacitive Temperature Sensor Using Flexible Polymer Layer

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Solution Overview

Problem

Existing temperature sensors face challenges in achieving high accuracy, reduced size, and cost-effectiveness while effectively measuring temperature variations on surfaces, particularly on curved objects.

Innovation Solution

A temperature sensor design featuring a flexible polymer layer with varying relative permittivity, paired with first and second electrodes on opposite surfaces, measures temperature changes in capacitance, allowing for accurate and flexible surface contact and low-cost manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a flexible polymer layer with varying relative permittivity is used, then temperature measurement accuracy and adaptability to curved surfaces are improved, but device complexity increases

Engineering Contradiction:

Improvetemperature measurement accuracyVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent utilizes changes in the relative permittivity parameter of the polymer layer in response to temperature variations. The polymer material exhibits temperature-dependent dielectric properties, allowing the capacitance between electrodes to change with temperature while maintaining a simple flexible structure that can conform to curved surfaces.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional mechanical temperature sensing mechanisms with an electrical field-based capacitance measurement system. Instead of using mechanical expansion or contact-based sensors, the invention uses the electrical properties of the polymer layer to detect temperature changes, simplifying the mechanical structure while improving measurement capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If a flexible polymer layer is used for surface contact, then adaptability to curved objects is improved, but manufacturing precision challenges increase

Engineering Contradiction:

Improveadaptability to curved surfacesVSAvoidmanufacturing precision

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent employs a flexible polymer layer as the core sensing element, which can bend and conform to curved surfaces without compromising its functional integrity. This flexible film structure allows the sensor to adapt to various object geometries while maintaining consistent electrical properties for accurate temperature measurement.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent uses composite material structures combining the flexible polymer layer with electrode patterns. This composite approach integrates the flexibility of the polymer with the electrical conductivity of the electrodes, creating a unified structure that is both manufacturable and adaptable to curved surfaces.

Inventive Principle:

Principle #40Composite materials

3Measurement precision

If capacitance-based measurement is used, then temperature resolution is improved, but device complexity increases

Engineering Contradiction:

Improvetemperature resolutionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent measures temperature by detecting changes in capacitance, which is a fundamental electrical parameter. The temperature-dependent relative permittivity of the polymer causes measurable capacitance variations between electrodes, providing high temperature resolution through simple capacitance measurement circuits without requiring complex sensing mechanisms.

Inventive Principle:

Principle #35Parameter changes

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 design provides high temperature resolution, flexibility for curved surfaces, and reduced size, enabling precise temperature measurement with improved cost-effectiveness.

Implementation Method 1

a polymer layer, a relative permittivity of the polymer layer varying in accordance with temperature

Methodology Applied

Scientific EffectTemperature-dependent relative permittivity: Dielectric Permittivity

Data Source

PatentUS11300459B2Capacitive temperature sensor

Publication Date: 2022.04.12 ALPS ALPINE CO LTD

AI summary

A temperature sensor includes a polymer layer, a relative permittivity of the polymer layer varying in accordance with temperature, the polymer layer being formed of a flexible material; at least one first electrode disposed on one surface of the polymer layer; at least one second electrode disposed on another surface of the polymer layer; and a measuring unit configured to measure a temperature of an object based on capacitance of at least one region between the first electrode and the second electrode that are separated by the polymer layer, the first electrode being closer than the second electrode to a surface of the object that contacts the temperature sensor.