Flexible Piezoelectric Vibration Actuators for Curved Surface Tactile Feedback

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Solution Overview

Problem

Conventional vibration presentation devices face challenges in generating uniform and effective tactile stimulation over a wide range due to differences in quality and quantity of vibratory stimulation between actuators and vibration expansion units, leading to weak stimulation at a distance and difficulty in attaching actuators to curved surfaces.

Innovation Solution

A vibration presentation device featuring a plurality of vibration units with a laminated structure using a dielectric layer and electrodes made of flexible materials, capable of expanding and contracting to generate vibrations, which can be shaped to fit curved surfaces and attached to wearable devices, allowing for independent control of vibrations to provide more preferred tactile stimulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a large number of joined vibration actuators are used to stimulate a wide range, then the coverage area is improved, but the device weight increases and adhesion to curved surfaces decreases

Engineering Contradiction:
Improvecoverage areaVSAvoiddevice weight
Core Design Contradiction:
Area of stationary objectVSWeight of moving object

Solution Approach 1:

The patent divides the vibration presentation function into multiple independent vibration units distributed across the wearable device. Each unit contains its own vibration actuator and control circuitry, allowing independent operation. This segmentation enables wide coverage area stimulation without requiring a single large heavy actuator, as multiple smaller units can be distributed across the device surface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from traditional single-point or linear vibration presentation to two-dimensional distributed vibration units across the wearable surface. This dimensional expansion allows coverage of curved surfaces and broader contact areas while maintaining individual unit lightness, solving the contradiction between coverage area and device weight.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If vibration actuators are arranged at certain intervals to attach to curved surfaces, then the ease of attachment is improved, but the stimulation becomes discrete and coverage is limited

Engineering Contradiction:
Improveease of attachmentVSAvoidcoverage area
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The patent employs flexible printed circuit boards (FPC) as the substrate for mounting vibration units, allowing the device to dynamically conform to curved surfaces like wrists or fingers. This flexibility enables continuous coverage along the curved surface while maintaining ease of attachment, resolving the contradiction between ease of attachment and coverage area.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The use of flexible printed circuit boards and thin-film vibration actuators allows the device to adapt to curved body surfaces. The flexible substrate enables the vibration units to be distributed continuously across the curved surface rather than at discrete intervals, improving both coverage area and ease of attachment to anatomical surfaces.

Inventive Principle:
Principle #30Flexible shells and thin films

3Weight of moving object

If piezoelectric films are used as thin lightweight actuators, then the device weight is reduced, but the power in low frequency regions is insufficient for vibratory stimulation

Engineering Contradiction:
Improveactuator weightVSAvoidvibratory power
Core Design Contradiction:
Weight of moving objectVSPower

Solution Approach 1:

The patent combines piezoelectric film actuators with flexible printed circuit board structures to create integrated vibration units. The FPC provides mechanical support and electrical connection while the piezoelectric film generates vibration. This merging allows the lightweight piezoelectric film to achieve sufficient vibratory power through the structural support and leverage provided by the FPC mounting structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The vibration units utilize composite construction combining piezoelectric film with flexible printed circuit board materials. This composite approach allows the lightweight piezoelectric element to achieve adequate power output for vibratory stimulation by leveraging the mechanical properties of the composite structure, resolving the contradiction between weight and power.

Inventive Principle:
Principle #40Composite materials

4Power

If conventional hard metal vibration actuators are used, then the vibratory power is sufficient, but the device complexity increases and adhesion to curved surfaces decreases

Engineering Contradiction:
Improvevibratory powerVSAvoiddevice complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent replaces traditional hard metal vibration actuators with piezoelectric film actuators mounted on flexible printed circuit boards. This substitution eliminates complex mechanical mounting structures and fastening mechanisms required for hard actuators, while maintaining sufficient vibratory power. The FPC provides both structural support and electrical connection in an integrated manner, reducing overall device complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The solution enables more effective and widespread tactile stimulation by allowing the vibration actuators to be easily attached to curved surfaces, improving adhesion and coverage, and providing controlled vibratory feedback that simulates realistic sensations such as movement and propagation.

Implementation Method 1

a vibration actuator 11 includes a dielectric layer 12, electrodes 13 and 14... when voltage is applied to the dielectric layer 12, the dielectric layer 12 expands and contracts... to generate vibration

Methodology Applied
Scientific EffectElectrostatic force: Electrostatics

Data Source

PatentEP3825822B1Vibration presentation device, vibration presentation method, and program
Publication Date: 2023.04.19 SONY GROUP CORP
  • EP3825822B1 patent drawingFigure 1
  • EP3825822B1 patent drawingFigure 2
  • EP3825822B1 patent drawingFigure 3

AI summary

The present disclosure relates to a vibration presentation device, a vibration presentation method, and a program that enable more preferred tactile stimulation. A vibration presentation device includes: a plurality of vibration actuators that vibrate when voltage is applied; and a control unit that controls vibration to be generated in the plurality of vibration actuators. The vibration actuators include a flexible, lightweight, and thin material, and are in surface contact with the portion to be presented with vibration. The control unit then generates a vibration signal for each of the plurality of vibration actuators, and controls the vibration for the plurality of vibration actuators independently of one another. The present technology can be applied to an apparatus that realizes tactile feedback such as VR and AR, for example.