Combined Piezo Sensor and Actuator for Compact Touch Screen Tactile Feedback

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Solution Overview

Problem

Traditional touch screen technologies for mobile devices face challenges in providing both touch screen input ability and tactile feedback in a compact and visually non-degrading manner, as separate systems often increase size and degrade visual output.

Innovation Solution

A combined piezo sensor and actuator device using a single piezo-electric material, where the piezo sensors detect user input and the piezo actuator provides tactile feedback, are electrically isolated but structurally coupled, allowing for efficient detection and feedback within a compact, generally rectangular form factor compatible with mobile display devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If separate tactile feedback elements are combined with touch screen display, then tactile feedback capability is improved, but device size increases excessively

Engineering Contradiction:
Improvetactile feedback capabilityVSAvoiddevice size
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The patent merges the tactile feedback elements with the touch screen display into a single integrated device. The feedback elements are positioned in direct contact with or adjacent to the display surface, allowing both functions to coexist within the same spatial envelope without requiring separate housings or mounting structures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated device serves multiple functions simultaneously - it provides both visual display output and tactile feedback through vibration or mechanical response. This multi-functionality eliminates the need for separate dedicated tactile feedback devices, reducing overall system volume.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If resistive layers are added to provide touch sensor functionality, then touch input capability is improved, but visual output quality degrades

Engineering Contradiction:
Improvetouch input capabilityVSAvoidvisual output quality
Core Design Contradiction:
Ease of operationVSIllumination intensity

Solution Approach 1:

The resistive layers are applied selectively to specific regions of the display rather than covering the entire surface. This localized application allows touch sensing functionality to be provided where needed while minimizing interference with the overall visual output quality of the display.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If traditional separate systems are used for touch input and tactile feedback, then functional versatility is improved, but device complexity increases

Engineering Contradiction:
Improvefunctional versatilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple control functions into a single integrated controller that manages both the touch sensor input and the tactile feedback actuator. This unified control architecture reduces the number of separate control circuits and interfaces needed, thereby reducing overall system complexity despite maintaining functional versatility.

Inventive Principle:
Principle #5Merging (Combining)

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 compact integration of touch screen input and tactile feedback, enhancing user experience by providing active tactility without degrading visual output, while maintaining the durability and cost-effectiveness of resistive touchscreens.

Implementation Method 1

A combined piezo sensor and actuator device is provided including a piezo actuator including a piezo-electric material and at least one piezo sensor formed of the piezo-electric material

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a piezo actuator including a piezo-electric material and at least one piezo sensor formed of the piezo-electric material

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP1946391B1Cost efficient element for combined piezo sensor and actuator in robust and small touch screen realization and method for operation thereof
Publication Date: 2015.08.19 NOKIA TECHNOLOGIES OY
  • EP1946391B1 patent drawingFigure 1a~2
  • EP1946391B1 patent drawingFigure 3

AI summary

A device comprising a piezo element includes a piezo-electric material the piezo element including a piezo actuator, and at least one piezo-sensor coupled to the piezo actuator, wherein the piezo actuator and the at least one piezo sensor include a common element.