Piezoelectric Actuator Tactile Feedback for Touch Input

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Solution Overview

Problem

Touch-sensitive input devices in portable electronic devices lack desirable tactile feedback, leading to user interaction errors such as double entry due to the absence of effective tactile feedback mechanisms.

Innovation Solution

The implementation of a touch-sensitive input surface with a piezoelectric actuator system, where a piezoelectric disk is coupled to a truncated metal substrate, allowing for controlled force application to simulate the actuation of a mechanical switch, providing recognizable tactile feedback to users.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a touch-sensitive input device is used in a portable electronic device, then the device size can be reduced and portability improved, but tactile feedback is lost leading to user interaction errors

Engineering Contradiction:

Improvedevice sizeVSAvoiduser interaction accuracy

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent replaces traditional mechanical tactile feedback mechanisms with a piezoelectric actuator system that generates controlled mechanical forces through electro-mechanical conversion. The piezoelectric material converts electrical signals into precise mechanical movements, providing tactile feedback without requiring bulky mechanical components, thus maintaining device compactness while improving interaction reliability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent dynamically adjusts the force parameters of the piezoelectric actuator to simulate different tactile sensations. By controlling the magnitude, duration, and frequency of electrical signals applied to the piezoelectric material, the system can vary mechanical force output to provide appropriate tactile feedback for different interaction scenarios, enhancing user confidence and reducing input errors

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If audio feedback is provided instead of tactile feedback, then device complexity is reduced, but user satisfaction and input confirmation are insufficient

Engineering Contradiction:

Improvefeedback mechanism complexityVSAvoiduser satisfaction

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The patent substitutes complex mechanical feedback mechanisms with a piezoelectric-based system that integrates electrical control with mechanical actuation. The piezoelectric actuator provides direct mechanical force generation through electrical signals, eliminating the need for complex mechanical linkages while delivering satisfying tactile feedback that enhances ease of operation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a piezoelectric actuator is used to provide tactile feedback, then tactile confirmation is improved, but device complexity increases

Engineering Contradiction:

Improveinput confirmationVSAvoidactuator system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent optimizes the piezoelectric actuator parameters including material selection, electrode configuration, and driving signal characteristics to achieve effective tactile feedback with minimal hardware. By carefully controlling electrical signal parameters such as voltage amplitude and pulse duration, the system provides reliable input confirmation while keeping the actuator design compact and integrated into the existing device structure

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 solution reduces the likelihood of user input errors, enhances user satisfaction, and improves interaction efficiency by providing tactile confirmation of input receipt.

Implementation Method 1

an actuator including a piezoelectric disk coupled to an elastically deformable substrate

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

an actuator including a piezoelectric disk coupled to an elastically deformable substrate, the substrate having a truncated disk shape

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2381338B1Portable electronic device including tactile touch-sensitive input device

Publication Date: 2012.12.12 BLACKBERRY LTD

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Figure 3A~3D

AI summary

An electronic device includes a base, a touch-sensitive input surface spaced from and moveable relative to the base, and an actuating arrangement between the base and the touch-sensitive input surface. The actuating arrangement is arranged to vary a force on the touch-sensitive input surface in response to detection of a touch event on the touch-sensitive input surface. The actuating arrangement includes an actuator including a piezoelectric disk coupled to a substrate that includes an elastically deformable truncated disk.