Cutaneous Facial Stimulation for Phosphene Control

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Solution Overview

Problem

Existing methods for generating phosphenes, particularly for visually impaired individuals, are invasive, uncomfortable, or not suited for wearable devices, and do not effectively convey spatial information.

Innovation Solution

A non-invasive system using pairs of electrodes on the skin to generate phosphenes through controlled voltage waveforms, allowing for predictable phosphene patterns that can convey spatial information, with features like biphasic square signals and minimal voltage to reduce discomfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If cutaneous electrical stimulation is used to generate phosphenes, then non-invasive visual information conveyance is achieved, but pain and uncomfortable sensations are caused

Engineering Contradiction:

Improvenon-invasive implementationVSAvoidpain and discomfort

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent employs alternating current (AC) stimulation with specific frequencies (e.g., 10-100 Hz) to generate phosphenes. The periodic nature of AC allows for controlled phosphene generation while enabling adaptation strategies where discomfort can be managed through frequency modulation and gradual exposure, transforming a harmful continuous stimulus into a manageable periodic one

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent systematically varies stimulation parameters including frequency (10-100 Hz), amplitude, and pulse width to optimize phosphene generation while minimizing discomfort. By changing these parameters, the system can operate at thresholds that produce visual effects without causing painful sensations, directly addressing the contradiction between effectiveness and comfort

Inventive Principle:

Principle #35Parameter changes

2Reliability

If high current intensities (300-900 μA) are applied to induce phosphenes, then reliable phosphene generation is achieved, but increased pain and discomfort occur

Engineering Contradiction:

Improvephosphene generation reliabilityVSAvoidpain and discomfort

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic adjustment of stimulation parameters based on individual user thresholds and responses. Rather than applying fixed high currents, the system adapts amplitude, frequency, and pulse width in real-time to maintain reliable phosphene generation at the lowest necessary intensity levels, thereby reducing pain while preserving effectiveness

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent explores using stimulation parameters that exceed traditional thresholds initially to map individual user responses, then back-off to optimal levels. This partial excessive action during calibration enables subsequent reliable operation at lower, more comfortable current intensities

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If electrode arrays are placed on the scalp, then phosphene generation is achieved, but hair shaving is required

Engineering Contradiction:

Improvephosphene generationVSAvoiduser convenience

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent employs cutaneous electrodes placed on the scalp surface that copy or simulate the electrical stimulation effects of intracranial electrodes without requiring surgical implantation. This surface-level copying approach maintains phosphene generation capability while eliminating the need for hair removal and surgical intervention

Inventive Principle:

Principle #26Copying

4Reliability

If analog means (transistors and op-amps) are used to generate stimulation signals, then phosphene stimulation is achieved, but the device cannot be made wearable

Engineering Contradiction:

Improvestimulation signal generationVSAvoidwearability

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces bulky analog electronics (transistors, op-amps) with digital signal generation and microcontroller-based control. This substitution enables integration into compact, wearable form factors while maintaining reliable stimulation signal generation, directly resolving the contradiction between signal reliability and device wearability

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 system effectively generates predictable phosphenes for spatial information transmission, reducing pain and enabling a non-invasive, wearable solution for visually impaired individuals.

Implementation Method 1

The most reproducible method for generating phosphenes is through electrical stimulation

Methodology Applied

Scientific EffectElectrical stimulation: Electrical Impedance Tomography

Data Source

PatentUS20230158300A1Precision phosphene control through cutaneous facial electrical stimulation

Publication Date: 2023.05.25 RYERSON UNIV

AI summary

A device and method for passing information to a person using cutaneous facial stimulation to generate phosphenes is described. This invention has many uses, but in particular it can be used to transmit visuo-spatial information to a person who is blind or has impaired vision. Electrodes are attached to the face in known positions, and stimulated in an order to create a desired phosphene pattern in the user's field of vision. Masks are described to assist with holding the electrodes in place and to carry associated circuitry and sensors. Voltage waveform conditions are also identified to minimize pain associated with the use of the device.