Laterally Driven Piezoelectric Actuators for Haptic Feedback

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Solution Overview

Problem

Piezoelectric actuators configured to output normal forces do not provide satisfying haptic feedback to mobile device users, as they often cause the display to flex and reduce its range of motion, leading to a less powerful haptic effect.

Innovation Solution

Implementing laterally driven piezoelectric actuators that apply forces in a direction parallel to the surface of the touch-screen or display, allowing for a more robust and consistent haptic feedback experience by displacing the touch-screen or touch-sensitive interface, which can be achieved through various configurations including mounting the actuators to the display or touch-sensitive interface, and using them as both actuators and suspensions to amplify the haptic effect.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If piezoelectric actuators output normal forces perpendicular to the display surface, then haptic feedback is provided, but the display flexes and range of motion is reduced

Engineering Contradiction:
Improvehaptic feedback forceVSAvoiddisplay range of motion
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The patent transitions from normal force output (perpendicular to display) to lateral force output (parallel to display surface). This dimensional change in force application allows the actuator to drive the touch-sensitive interface laterally without causing display flexing, resolving the contradiction between providing haptic feedback force and maintaining display range of motion.

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

2Force

If piezoelectric actuators output normal forces, then haptic feedback is generated, but the haptic effect is less powerful

Engineering Contradiction:
Improvehaptic feedback forceVSAvoidhaptic effect intensity
Core Design Contradiction:
ForceVSPower

Solution Approach 1:

By changing the force output direction from normal to lateral, the system achieves more powerful haptic effects. The lateral driving configuration allows for more efficient force transmission to the touch-sensitive interface without the energy loss associated with display flexing, thereby increasing haptic effect intensity.

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

3Force

If multiple actuators are used for haptic feedback, then haptic performance is improved, but device complexity and cost increase

Engineering Contradiction:
Improvehaptic feedback forceVSAvoidactuator configuration
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The laterally driven piezoelectric actuator serves multiple functions: it provides haptic feedback, acts as a suspension mechanism, and amplifies haptic effects through its coupling with the touch-sensitive interface. This multi-functionality allows a single actuator to replace what would traditionally require multiple components, reducing device complexity while maintaining or improving haptic performance.

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 approach reduces the likelihood of display bending, enhances the intensity and consistency of haptic feedback, increases the operating life of the device, and allows for a more compact and cost-effective design by using a single actuator, while providing a more robust and lighter device with reduced spacing between the display and touch-screen.

Implementation Method 1

a piezoelectric actuator in communication with the processor. The piezoelectric actuator is configured to receive a haptic signal from the processor and, in response to the haptic signal, output a haptic effect by applying a force in a direction laterally along the surface of the touch-screen or display

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2534558B1System for haptic feedback using laterally driven piezoelectric actuators
Publication Date: 2020.01.22 IMMERSION CORP
  • EP2534558B1 patent drawingFigure 1
  • EP2534558B1 patent drawingFigure 2A~2B
  • EP2534558B1 patent drawingFigure 3

AI summary

Systems and methods for haptic feedback using laterally driven piezoelectric actuators are disclosed. For example, one described apparatus for haptic feedback using laterally driven piezoelectric actuators includes: a base; a touch-sensitive interface comprising an interface surface, the touch-sensitive interface affixed to the base and configured to move in a direction lateral to the interface surface; and a piezoelectric actuator mounted to the base and to the touch-sensitive interface and configured to receive a haptic signal and output a force in a direction lateral to the interface surface.