Surface Electrode Touch Stimulus via Friction Modulation
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Solution Overview
Problem
Current electromechanical actuators, such as vibrators, used for creating touch stimuli have limitations in effectively generating perceivable tactile feedback, particularly when used in applications requiring dynamic touch sensations.
Innovation Solution
An apparatus with a body having a first and second surface electrode, where a controller applies a time-varying potential difference between the electrodes, generating a modulating electric field that creates a perceived 'texture' when a digit is traced over the surface, without direct nerve or muscle activation, using electric currents below 100 μA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromechanical actuators such as vibrators are used to create touch stimulus, then touch stimulus can be generated, but the effectiveness of generating perceivable tactile feedback is limited
Solution Approach 1:
The patent replaces electromechanical vibrators with an electrical field-based system. Surface electrodes apply time-varying potential differences to generate electric fields that modulate frictional forces on the skin, creating tactile feedback without mechanical vibration. This substitution enables more effective and adaptable touch stimulus generation.
Solution Approach 2:
The patent changes the operating parameters by using time-varying potential differences (frequency, amplitude, duty cycle) instead of mechanical vibration amplitude and frequency. This allows dynamic modulation of tactile sensations through electrical parameter control, providing superior adaptability for generating diverse touch sensations.
2Adaptability or versatility
If traditional vibrators are used for touch stimulus, then simple tactile feedback can be provided, but dynamic touch sensations and information conveyance are ineffective
Solution Approach 1:
The patent divides the touch stimulus generation into multiple independent surface electrodes that can be individually controlled. Each electrode can apply different time-varying potential differences, enabling spatially distributed dynamic tactile patterns. This segmentation provides manufacturing simplicity while achieving high adaptability.
Solution Approach 2:
The surface electrode system serves multiple functions: generating tactile feedback, conveying information through varying textures, and providing dynamic touch sensations. The same electrical field generation mechanism accomplishes all these functions, simplifying the overall apparatus structure while enhancing versatility.
3Reliability
If electric current is applied to directly stimulate nerves or muscles for touch feedback, then strong tactile response can be achieved, but safety concerns arise from direct nerve activation
Solution Approach 1:
The patent introduces frictional force modulation as an intermediary mechanism between electrical field application and tactile perception. The time-varying electric fields modulate the friction between the skin and a tracing digit, creating tactile feedback indirectly without direct nerve or muscle stimulation. This intermediary approach maintains strong tactile response while eliminating safety risks.
Solution Approach 2:
The patent applies partial action by using electric currents below 100 μA, which is insufficient to directly activate nerves or muscles but sufficient to modulate frictional forces and generate perceptible tactile feedback. This partial application of electrical current achieves the desired tactile effect without harmful side effects.
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 the creation of an electrically modulated moving touch stimulus that provides a dynamic tactile feedback, allowing for the conveyance of information through varying textures, enhancing user interaction with devices by modulating frictional forces without direct nerve stimulation.
Implementation Method 1
a controller configured to apply a time varying potential difference between the first surface electrode and the second surface electrode
Implementation Method 2
The electric field produces a time-varying force that does not directly create a touch stimulus at an overlying and touching digit of a user when the digit is stationary but does provide a touch stimulus indirectly when the digit of the user, while in contact with the second surface electrode, is traced over the second surface electrode. It is believed that the time varying force modulates the frictional force applied to the touching digit
Data Source
AI summary
Apparatus including: a body portion having a surface comprising a first surface electrode and a second surface electrode, spaced from the first surface electrode, and a controller configured to apply a time varying potential difference between the first surface electrode and the second surface electrode and configured to control at least the time variation in the potential difference.