Touch Panel Sensor Switching for Sound Output and Press Detection

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Solution Overview

Problem

Conventional touch type input devices cannot simultaneously detect operation inputs and emit sound effectively due to independent operation input detecting and sound emission circuits, making it difficult to accurately detect pressing amount and position during sound emission.

Innovation Solution

A touch type input device integrating a piezoelectric sensor and an electrostatic sensor within a single touch panel, with a controller and switch unit that allows for seamless switching between sound emission and pressing amount detection, enabling operation input detection during sound emission and accurate pressing position detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a relay circuit is used to switch between operation input detecting circuit and sound emission signal applying circuit, then both functions can be performed using one touch panel, but the voltage generated by pressing the piezoelectric film cannot be detected during sound emission

Engineering Contradiction:

Improvedual function capabilityVSAvoiddetection capability during sound emission

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent divides the single piezoelectric film into two functional regions: a first region with a first electrode for sound emission and a second region with a second electrode for operation input detection. This spatial segmentation allows both sound emission and detection functions to operate simultaneously without mutual interference, resolving the contradiction between dual-function capability and detection reliability during sound emission.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If independent operation input detecting and sound emission circuits are used, then each function can operate independently, but the device configuration becomes complex and detection accuracy during sound emission deteriorates

Engineering Contradiction:

Improveindependent function operationVSAvoidcircuit configuration

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the sound emission function and operation input detection function into a single integrated circuit that shares one piezoelectric film, one controller, and one power supply. The piezoelectric film is divided into multiple regions with different electrode configurations, allowing both functions to coexist in a unified structure rather than requiring separate independent circuits, thus reducing overall device complexity while maintaining functional independence.

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If one touch panel is used for both sound emission and operation input detection, then device structure is simplified, but it is difficult to accurately detect pressing amount and position during sound emission

Engineering Contradiction:

ImprovestructureVSAvoidpressing amount and position detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the piezoelectric film into distinct functional regions: a first region dedicated to sound emission with its electrode configuration, and a second region dedicated to operation input detection with its electrode configuration. This spatial segmentation eliminates signal interference between the two functions, enabling accurate detection of pressing amount and position even during sound emission, while maintaining a simplified single-touch-panel structure.

Inventive Principle:

Principle #1Segmentation

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

Enables reliable operation input detection and pressing amount measurement while emitting sound using a single touch panel, simplifying the device configuration and improving detection sensitivity and sound emission efficiency.

Implementation Method 1

a piezoelectric sensor and an electrostatic sensor that are integrally formed in a touch panel

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

electrodes are formed on both surfaces of a piezoelectric film, and a voltage generated by pressing the piezoelectric film is detected by the electrodes on both the surfaces

Methodology Applied

Scientific EffectElectrostatic capacitance: Capacitance

Data Source

PatentUS9582103B2Touch type input device having a piezoelectric sensor connected to a displacement detector and a sound emission controller by a switch

Publication Date: 2017.02.28 MURATA MFG CO LTD

AI summary

A touch panel having a piezoelectric sensor and an electrostatic sensor that are integrally formed. The piezoelectric sensor is connected to a displacement detector and a sound emission amplifier through a relay switch. A controller performs switch control on the relay switch. The piezoelectric sensor emits sound while the sound emission amplifier and the piezoelectric sensor are connected to each other by the relay switch. When the operation input is detected through the electrostatic sensor and the touch position detector, the controller performs the switch control on the relay switch to connect the piezoelectric sensor to the displacement detector. A detection voltage is input from the piezoelectric sensor to the displacement detector to also detect the pressing amount.