Transparent Piezoelectric Touch Sensor and Haptic Actuator

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Solution Overview

Problem

Conventional haptic feedback devices face challenges with scalability, fragility, and integration difficulties due to bulky actuators and high voltage requirements, limiting their application in consumer products.

Innovation Solution

A transparent composite piezoelectric combined touch sensor and haptic actuator is developed, featuring a substrate with a sensor piezoelectric layer that generates signals upon deformation and an actuator layer providing haptic effects, allowing for flexible and compact integration in user devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional haptic actuators (LRA, ERM) are used, then haptic feedback can be provided, but the devices become bulky and difficult to scale

Engineering Contradiction:
Improvehaptic feedback capabilityVSAvoidactuator size
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The patent combines the touch sensor and haptic actuator into a single integrated piezoelectric element. The piezoelectric material serves dual functions: sensing touch input through deformation and generating haptic feedback through controlled actuation, eliminating the need for separate bulky actuators and enabling compact device design

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention transitions from conventional electromagnetic actuators to piezoelectric actuators, changing the fundamental operating parameter from electromagnetic fields to piezoelectric deformation. This parameter change enables much smaller actuator sizes while maintaining haptic feedback capability, as piezoelectric materials can generate significant force at microscopic scales

Inventive Principle:
Principle #35Parameter changes

2Strength

If EAP-based actuators are used, then haptic effects can be provided, but thousands of volts of electricity are required

Engineering Contradiction:
Improvehaptic effect capabilityVSAvoidvoltage requirement
Core Design Contradiction:
StrengthVSPower

Solution Approach 1:

The patent changes the operating voltage parameter from thousands of volts (EAP) to standard low-voltage electrical signals (typically 0-5V). The piezoelectric material responds to small voltage changes by undergoing mechanical deformation, enabling haptic feedback with conventional electronics without requiring high-voltage power supplies

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses standard piezoelectric ceramics or polymers that operate with low-voltage electronics, replacing the need for complex high-voltage power supply systems. This makes the haptic device more practical for consumer electronics where cost and power consumption are critical factors

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If monolithic piezoelectric ceramics are used, then scalability and fast dynamics are achieved, but the ceramics are fragile and difficult to integrate

Engineering Contradiction:
Improvescalability and response speedVSAvoidmechanical strength
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent employs composite piezoelectric structures combining ceramic particles or fibers with a flexible polymer matrix. This composite approach retains the fast response and scalability of piezoelectric ceramics while the polymer matrix provides mechanical flexibility and fracture toughness, preventing catastrophic failure under stress or impact

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention uses thin-film piezoelectric layers deposited on flexible substrates or embedded in flexible polymers. This thin-film configuration maintains the fast dynamic response of piezoelectric materials while the flexible substrate provides mechanical robustness and enables integration into curved or flexible device surfaces, eliminating the brittleness problem of bulk ceramics

Inventive Principle:
Principle #30Flexible shells and thin films

4Ease of operation

If separate touch sensors and haptic actuators are used, then touch sensing and haptic feedback can be provided, but device complexity increases

Engineering Contradiction:
Improvetouch sensing and haptic feedback functionalityVSAvoidintegration complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the touch sensor and haptic actuator into a single piezoelectric element that performs both functions. The same piezoelectric material that deforms to create haptic feedback also generates electrical signals when deformed by touch, eliminating the need for separate sensor and actuator components and simplifying device architecture

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The piezoelectric element serves multiple functions simultaneously: it acts as both the actuator for haptic feedback and the sensor for touch detection. This multi-functionality reduces the total component count, simplifies integration, and lowers manufacturing complexity while maintaining full touch sensing and haptic feedback capability

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

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 rich haptic feedback with improved mechanical strength, scalability, and simplified integration, providing a thinner, more compact haptic experience suitable for various applications, including touch screens, while eliminating the need for external voltage for sensor functionality.

Implementation Method 1

a sensor piezoelectric layer configured to generate a first signal when the sensor piezoelectric layer is deformed

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

an actuator piezoelectric layer configured to provide a haptic effect upon receipt of a second signal

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3333676B1Transparent piezoelectric combined touch sensor and haptic actuator
Publication Date: 2019.09.11 IMMERSION CORP
  • EP3333676B1 patent drawingFigure 1~2A
  • EP3333676B1 patent drawingFigure 2B~2C
  • EP3333676B1 patent drawingFigure 3~4

AI summary

There is provided a haptic device comprising a substrate and a substantially transparent composite piezoelectric cell overlaying the substrate. The piezoelectric cell comprises a sensor piezoelectric layer configured to generate a first signal when the sensor piezoelectric layer is deformed and an actuator piezoelectric layer configured to provide a haptic effect upon receipt of a second signal that is based on the first signal. The substantially transparent composite piezoelectric cell is configured to measure a deformation of a surface of the cell and to provide a haptic feedback effect as a result of the deformation.