Force Sensors and Piezo Actuators for Touch Feedback

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Solution Overview

Problem

Portable electronic devices with touch-sensitive displays face challenges in efficiently detecting and distinguishing between multiple touches and providing accurate tactile feedback, which can lead to increased error rates and user interaction complexity due to limited space and the need for precise force measurement.

Innovation Solution

Incorporating a plurality of force sensors and piezoelectric actuators that work in conjunction with a touch-sensitive display to detect touches, determine their locations, and apply forces to simulate tactile feedback, such as dome switch actions, allowing for accurate force measurement and feedback to enhance user interaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple force sensors are used to detect touches and provide tactile feedback, then measurement precision and user interaction quality improve, but device complexity increases

Engineering Contradiction:

Improvetouch force detection accuracyVSAvoidsensor and actuator system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The back surface of the touch-sensitive display is divided into multiple discrete force sensor locations, with each sensor independently detecting force at its specific position. This segmentation allows precise localization of touch forces while maintaining a relatively simple overall structure, as each sensor operates independently rather than requiring a complex continuous sensing mechanism.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple force sensors and piezoelectric actuators are integrated into a unified system where sensors detect touch forces and actuators provide tactile feedback at the same locations. This merging of detection and feedback functions at corresponding positions simplifies the system architecture while achieving both precise measurement and effective user interaction.

Inventive Principle:

Principle #5Merging (Combining)

2Manufacturing precision

If force sensors and piezoelectric actuators are integrated with the touch-sensitive display, then tactile feedback accuracy improves, but manufacturing complexity increases

Engineering Contradiction:

Improvetactile feedback accuracyVSAvoidassembly and integration difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Piezoelectric actuators are positioned and pre-configured at specific locations on the back surface of the touch-sensitive display before final assembly. This preliminary placement ensures that actuators are correctly aligned with corresponding force sensors and display regions, facilitating more accurate tactile feedback while simplifying the final assembly process by reducing complex alignment requirements.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If multiple touches are detected and distinguished, then user interaction capability improves, but error rates increase due to detection complexity

Engineering Contradiction:

Improvemulti-touch capabilityVSAvoidtouch detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The touch detection surface is segmented into multiple independent detection zones, each with its own force sensor. This segmentation allows the system to independently detect and distinguish multiple simultaneous touches at different locations, reducing confusion and error rates that would occur with a single undifferentiated sensor. Each sensor provides reliable data for its specific zone while the system integrates information from all zones for comprehensive multi-touch capability.

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

This solution enables precise detection of touch forces and locations, reducing entry errors and improving user interaction efficiency by providing effective tactile feedback, thus enhancing the usability of portable electronic devices with touch-sensitive displays.

Implementation Method 1

determining, by a plurality of force sensors, reaction forces, for the first and second touches

Methodology Applied

Scientific EffectForce sensing: Force

Implementation Method 2

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS10114495B2Portable electronic device including touch-sensitive display and method of controlling same

Publication Date: 2018.10.30 MALIKIE INNOVATIONS LTD

AI summary

A method includes detecting first and second touches on the touch-sensitive display and determining a location of each of the first and second touches, determining, by a plurality of force sensors, reaction forces, for the first and second touches, and determining a respective applied force for each of the first and second touches based on the reaction forces and the locations of the first and second touches.