Touch Event Classification via Mechanical Vibration Signatures

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Solution Overview

Problem

Current touch interaction systems on touch-sensitive surfaces fail to effectively differentiate between various finger inputs and passive tools, leading to oversimplification of finger operations, particularly on mobile devices with limited screen real estate, where complex actions require finger overloading or multiple buttons.

Innovation Solution

An apparatus and method that classify touch events by converting mechanical vibrations from finger parts or passive tools into electrical signals, extracting features, and using these features to identify the object used for the touch event, allowing for distinct user interface actions without the need for active components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If touch events are treated as a single class of input, then the system is simple to implement, but it cannot differentiate between various finger inputs and passive tools

Engineering Contradiction:
Improvetouch input differentiationVSAvoidclassification system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses mechanical vibration analysis to differentiate between various finger inputs and passive tools. Vibration sensors detect the unique vibration signatures produced when different objects (fingertip, fingerpad, fingernail, passive tools) contact the touch-sensitive surface. The system extracts vibration features such as frequency, amplitude, and temporal characteristics to classify touch events, enabling nuanced input recognition without requiring active components on the input objects.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The patent replaces complex mechanical instrumentation of input objects with a passive vibration detection system. Instead of requiring active sensors, batteries, or electronic components on fingers or tools, the system uses the touch-sensitive surface itself to detect and analyze mechanical vibrations. This substitution maintains simplicity while achieving sophisticated input differentiation through acoustic/vibration analysis.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If finger overloading or multiple buttons are used to achieve complex actions, then more functions are available, but screen real estate is reduced and usability deteriorates

Engineering Contradiction:
Improvefinger input capabilityVSAvoiduser interface usability
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent segments finger input into multiple distinguishable categories based on vibration characteristics: fingertip, fingerpad, fingernail, and passive tool contacts. Each segment produces a unique vibration signature that the system can识别 and respond to differently. This segmentation enables multiple functions to be triggered by different parts of the same finger without requiring additional buttons or screen space, improving both versatility and ease of operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent makes the single finger multi-functional by enabling it to trigger different actions based on which part contacts the screen. The same finger can perform multiple functions (select, delete, confirm, etc.) by varying the contact point, eliminating the need for multiple physical buttons or complex gesture combinations. This universal approach improves usability while maintaining access to diverse functions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If passive tools are used without active components, then the system is simpler and more scalable, but the ability to identify and classify different tools is limited

Engineering Contradiction:
Improvetool simplicityVSAvoidobject identification accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent uses vibration signature variations as analogous to 'color changes' for identifying passive tools. Different tool materials (metal, plastic, wood) produce distinct vibration characteristics when contacting the touch surface. The system analyzes these vibration 'colors' to identify and classify passive tools accurately, maintaining tool simplicity while achieving precise identification through material-dependent vibration analysis.

Inventive Principle:
Principle #32Color 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

Enables nuanced finger input recognition on touch-sensitive surfaces, allowing for secondary actions without overloading fingers or requiring additional buttons, enhancing usability on mobile devices by utilizing passive tools and finger parts to generate distinct mechanical vibrations.

Implementation Method 1

the touch event entails a mechanical vibration upon contact with the surface

Methodology Applied
Scientific EffectMechanical vibration: Vibration

Implementation Method 2

a touch sensitive surface configured to generate a touch event when an object touches the touch sensitive surface, wherein the touch event entails a mechanical vibration upon contact with the surface

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2769291B1Method and apparatus for classifying touch events on a touch sensitive surface
Publication Date: 2021.04.28 CARNEGIE MELLON UNIV
  • EP2769291B1 patent drawingFigure 1
  • EP2769291B1 patent drawingFigure 2
  • EP2769291B1 patent drawingFigure 3

AI summary

An apparatus classifies touch events. The apparatus includes a touch sensitive surface configured to generate a touch event when an object touches the touch sensitive surface. The touch event entails a mechanical vibration upon contact with the surface. The apparatus includes a touch event detector configured to detect the onset of a touch, and a touch event classifier configured to classify the touch event to identify the object used for the touch event. The mechanical vibration is created via any one of finger parts including a tip, a pad, a fingernail, and a knuckle, each of which has a unique feature different from each other.