Touch Panel Temperature Compensation via Dielectric Constant

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Touch panel devices experience erroneous judgments in touch operations due to temperature variations affecting the properties of elastic members, leading to false detection of touch operations or failure to detect intended touches.

Innovation Solution

A touch panel device with a cover panel, a touch sensor unit, and an elastic member with a dielectric constant that changes with temperature, utilizing a first sensor unit to detect capacitance and estimate temperature, allowing for accurate detection of depressing force and processing of touch sensor signals to inhibit erroneous judgments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the elastic member is used to detect touch operations, then the touch panel can detect touch operations with depressing force, but temperature variations cause changes in the elastic member's properties leading to erroneous judgments

Engineering Contradiction:

Improvetouch operation detection accuracyVSAvoidtemperature variation influence

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A first sensor unit is introduced as an intermediary component to detect the dielectric constant of the elastic member independently. This mediator provides temperature information that is then used to correct the touch operation detection, eliminating the harmful effect of temperature variations on the elastic member's performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system monitors changes in the dielectric constant parameter of the elastic member, which varies with temperature. By detecting this parameter change through the first sensor unit, the system can compensate for temperature effects and maintain accurate touch operation detection despite environmental temperature variations

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the elastic member's dielectric constant changes with temperature, then temperature can be detected, but this causes erroneous judgment of touch operations under temperature variations

Engineering Contradiction:

Improvetemperature detection capabilityVSAvoidtouch operation judgment accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The first sensor unit provides feedback about the dielectric constant (and thus temperature) of the elastic member to the processing circuitry. This feedback loop enables the system to adjust its touch detection threshold or parameters based on the current temperature, preventing erroneous judgments while maintaining accurate temperature detection

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The dielectric constant serves as an intermediary parameter that links temperature to touch detection accuracy. By measuring the dielectric constant through capacitance changes, the system obtains temperature information that is then used to correct touch operation detection, converting a harmful effect into a useful correction mechanism

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively reduces detection errors of depressing force due to temperature variations, thereby minimizing erroneous judgments in touch operations even under significant temperature changes.

Implementation Method 1

a first sensor unit that detects a capacitance changing depending on the dielectric constant and a thickness of the elastic member

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

an elastic member that has a dielectric constant changing corresponding to a temperature

Methodology Applied

Scientific EffectDielectric constant: Dielectric Permittivity

Implementation Method 3

an elastic member that has a dielectric constant changing corresponding to a temperature and deforms due to the bending of the cover panel

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS11868563B2Touch panel device, touch panel control method, and storage medium storing touch panel control program

Publication Date: 2024.01.09 MITSUBISHI ELECTRIC MOBILITY CORP

AI summary

A touch panel device includes a cover panel that has an operation surface and bends corresponding to a depressing force applied to the operation surface; a touch sensor unit including touch sensor electrodes that output touch sensor signals; an elastic member that has a dielectric constant changing corresponding to a temperature and deforms due to the bending of the cover panel, the elastic member including an adhesive agent provided between the cover panel and the touch sensor unit; a first sensor unit that detects a capacitance changing depending on the dielectric constant and a thickness of the elastic member; and processing circuitry to estimate the temperature based on the capacitance detected by the first sensor unit; to detect the depressing force based on the estimated temperature and the capacitance detected by the first sensor unit; and to execute processing of the touch sensor signals based on the detected depressing force.