Segmented Piezoelectric Haptic Actuators With Sealed Encapsulation

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Solution Overview

Problem

Conventional haptic actuators face limitations in generating localized haptic output due to the interference of encapsulation materials with the operation of haptic systems, and they often trade off between the magnitude and localization of haptic output.

Innovation Solution

The use of piezoelectric material with individually controllable voltage electrodes allows for localized haptic output by applying voltage to different portions of the material, enabling greater haptic resolution and magnitude without the need for larger monolithic structures, while encapsulated haptic elements provide protection to sensitive components using techniques like lamination and sealing with flexible circuits and anisotropic conductive tapes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional encapsulation techniques are used to protect haptic components, then mechanical and electrical protection is provided, but the encapsulation materials interfere with the operation of the haptic output system

Engineering Contradiction:
Improveprotection of haptic componentsVSAvoidinterference with haptic system operation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

An anisotropic conductive film is introduced as an intermediary layer between the encapsulation structure and the piezoelectric actuator. This film allows electrical signals to pass through to activate the haptic element while preventing direct contact between encapsulation materials and the actuator, thereby eliminating interference while maintaining protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs thin film encapsulation structures that provide mechanical protection without the bulk and interference of conventional encapsulation materials. The thin film design allows the haptic actuator to operate effectively while still being protected from environmental factors.

Inventive Principle:
Principle #30Flexible shells and thin films

2Force

If larger monolithic piezoelectric structures are used to increase haptic magnitude, then greater deflection is achieved, but the device dimensions and complexity increase

Engineering Contradiction:
Improvehaptic magnitudeVSAvoiddevice dimensions
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The piezoelectric actuator is divided into multiple independently controllable segments or regions. By applying voltage to different segments, the system can generate haptic output at specific locations without requiring a large monolithic structure. This segmentation allows for localized haptic feedback with high resolution while maintaining compact device dimensions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the piezoelectric material are activated selectively based on the desired haptic output location. This local quality approach allows the system to concentrate energy where needed, achieving high haptic magnitude at specific points without increasing overall device size.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If electrode patterning is used to achieve localized haptic output, then haptic resolution is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvehaptic resolutionVSAvoidelectrode patterning process
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent employs droplet-based printing techniques to create electrode patterns by controlling the placement and volume of conductive material droplets. This approach simplifies the manufacturing process compared to traditional photolithography, as it requires fewer processing steps and allows for direct writing of complex electrode geometries with high precision.

Inventive Principle:
Principle #35Parameter changes

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 enables high-resolution, localized haptic feedback with enhanced magnitude and protection of sensitive components, improving user interaction and device durability.

Implementation Method 1

piezoelectric material and voltage electrodes or conductors coupled thereto. The voltage electrodes are individually controllable to supply voltage to different portions of the piezoelectric material. Different sections of the piezoelectric material are operable to deflect, producing haptic output at those locations

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3260953B1Localized and/or encapsulated haptic actuators and elements
Publication Date: 2024.03.20 APPLE INC
  • EP3260953B1 patent drawingFigure 1
  • EP3260953B1 patent drawingFigure 2
  • EP3260953B1 patent drawingFigure 3

AI summary

In some embodiments, a haptic actuator includes piezoelectric material and a pattern of voltage electrodes coupled to a surface of the piezoelectric material. The voltage electrodes are individually controllable to supply voltage to different portions of the piezoelectric material. Different sections of the piezoelectric material are operable to deflect, producing haptic output at those locations, in response to the application of the voltage. Differing voltages may be provided to one or more of the voltage electrodes to affect the location of the deflection, and thus the haptic output. In various embodiments, a haptic output system incorporates a sealed haptic element. The sealed haptic element includes a piezoelectric component that is coupled to one or more flexes and is sealed and/or enclosed by the flex(es) and an encapsulation or sealing material.