Localized Haptic Feedback via Piezoelectric Actuators and PSA
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Solution Overview
Problem
Existing electronic devices often provide non-localized haptic feedback, vibrating the entire device when a button is pressed, which does not inform users which specific action initiated the feedback, lacking precision in user interaction.
Innovation Solution
The use of pressure-sensitive adhesive (PSA) and piezoelectric haptic actuators within an electronic device's housing, where a sensor module detects the compression force applied by an extending member, allowing for localized haptic feedback by applying a counter-force through the actuator, providing feedback only to the pressed button.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional vibration motors are used to provide haptic feedback, then the device can deliver haptic feedback, but the feedback is non-localized and vibrates the entire device
Solution Approach 1:
The housing is divided into multiple slots, each containing its own actuator and sensor module. This segmentation allows each button to have a dedicated actuator that provides localized haptic feedback only to that specific button, rather than vibrating the entire device. The segmentation of the housing into discrete slots with individual actuators enables precise spatial localization of haptic feedback.
Solution Approach 2:
Each slot contains an actuator and sensor module specifically configured for that location, providing localized haptic feedback properties. The actuator in each slot is positioned to contact only the extending member of its corresponding button, ensuring that haptic feedback is applied locally to the pressed button rather than globally to the entire device. This local quality approach allows different parts of the device to have different haptic characteristics.
2Reliability
If the sensor module is exposed to the actuator's extending member, then localized haptic feedback can be detected, but the sensor module becomes vulnerable to water and contamination
Solution Approach 1:
The PSA layer acts as an intermediary between the actuator's base surface and the support surface, providing both mechanical coupling for haptic feedback transmission and environmental sealing. The PSA allows the extending member to contact the sensor module through the support surface while simultaneously sealing the sensor module against water and contaminants. This intermediary layer enables the sensor to function locally while being protected from the external environment.
Solution Approach 2:
The PSA layer functions as a flexible sealing film that allows mechanical interaction while providing environmental protection. The thin film nature of the PSA enables the extending member to contact the sensor module through it, while the film's sealing properties prevent water and contaminants from reaching the sensor module. This flexible film approach maintains both protection and functionality.
3Force
If a rigid interface is used between the actuator and sensor module, then mechanical coupling is strong, but haptic feedback transmission is less effective
Solution Approach 1:
The PSA layer changes the mechanical parameters of the interface between the actuator and sensor module, providing both coupling strength and compliance. By using a material with specific viscoelastic properties, the PSA allows effective transmission of haptic feedback forces while accommodating minor misalignments and providing damping. This parameter change approach optimizes both force transmission and mechanical strength.
Solution Approach 2:
The interface combines the rigid actuator structure with the compliant PSA material to create a composite coupling system. The rigid actuator provides the driving force, while the PSA material provides compliant coupling that enhances force transmission efficiency. This composite approach allows the rigid actuator to effectively transmit haptic feedback through the compliant PSA layer to the sensor module.
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 precise localized haptic feedback, informing users which specific action was registered, enhancing user interaction by simulating touch sensations specific to the button pressed, while maintaining waterproofing and preventing contamination.
Implementation Method 1
sensor module positioned within the housing such that the support surface of the frame is arranged between the sensor module and the base surface of the actuator... the sensor module is configured to detect a compression force applied by the second end of the extending member
Implementation Method 2
A PSA is positioned between the base surface of the actuator and the support surface of the frame. The PSA provides waterproofing capability for the sensor module and forms a compressible interface between the actuator and the sensor module
Data Source
AI summary
This document describes techniques and apparatuses directed at localized haptic feedback in electronic devices using pressure-sensitive adhesive (PSA) and piezoelectric haptic actuators. In aspects, an electronic device includes a housing having a frame defining a slot. An actuator is adhered to the frame at the bottom of the slot by the PSA. When a force is applied to an exterior surface of the actuator (“button press”), the PSA compresses and an extending member attached to the actuator, opposite the exterior surface, slidably moves within an aperture in the frame at the bottom of the slot. The extending member engages a sensor module (e.g., piezoelectric sensor) and the electronic device registers a button press. The sensor module then applies haptic feedback to the extending member and through the actuator to the exterior surface. When the force is removed from the actuator's exterior surface, the PSA expands to an approximate original thickness.