Ambient Light Sensors for Touchless Gesture Detection

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Solution Overview

Problem

Touchscreens on mobile devices face issues with accuracy due to finger obstruction during input and maintenance concerns from fingerprints and smudges, prompting the need for alternative input methods.

Innovation Solution

The use of ambient light sensors arranged beneath the screen to detect touch-less gestures by measuring changes in ambient light intensity, allowing for gesture recognition without physical contact, using a system with multiple sensors in a triangular pattern to detect movement in three dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If capacitive touch sensors are used for navigation and data input, then the device can be operated without a mouse or equivalent input interface, but the user's finger obstructs the screen during input and leaves fingerprints and smudges

Engineering Contradiction:
Improveoperation without mouseVSAvoidfinger obstruction and smudges
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical contact-based capacitive touch sensor system with an optical detection system using ambient light sensors. Instead of requiring physical finger contact to generate electrical signals, the system detects changes in ambient light caused by the presence and movement of a finger or object, thereby eliminating the need for mechanical contact while maintaining input functionality.

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

Solution Approach 2:

The patent introduces ambient light as an intermediary medium between the user and the device. Rather than direct finger contact with the screen, the user's finger modifies the ambient light field, and the light sensors detect these modifications. This intermediary approach allows input without physical contact, solving both the obstruction and smudge problems.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple ambient light sensors are arranged in a triangular pattern to detect three-dimensional movement, then gesture detection accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvegesture detection accuracyVSAvoidsensor arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the sensing function across multiple discrete ambient light sensors arranged in a triangular pattern beneath the screen. Each sensor independently measures light intensity at its specific location, and the collective data from all sensors enables three-dimensional gesture detection. This segmentation allows accurate spatial measurement while maintaining modular simplicity in each individual sensor component.

Inventive Principle:
Principle #1Segmentation

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 solution enhances input accuracy by allowing gesture recognition without obstructing the screen and reduces maintenance concerns by eliminating finger smudges, providing a reliable and efficient touch-less gesture detection system.

Implementation Method 1

the optical sensors are used to detect changes in ambient light that result from a shadowing effect of an object in proximity to, or in contact with, the touch screen display

Methodology Applied
Scientific EffectShadowing effect: Shadow

Data Source

PatentEP2821888B1Gesture detection using ambient light sensors
Publication Date: 2019.06.12 BLACKBERRY LTD
  • EP2821888B1 patent drawingFigure 1
  • EP2821888B1 patent drawingFigure 2
  • EP2821888B1 patent drawingFigure 3

AI summary

A device and method to detect a gesture made by an object in touch-less communication with the device are described. The device includes two or more ambient light sensors arranged at respective surface locations of the device, each of the two or more ambient light sensors configured to measure light intensity at the respective surface location. The device also includes a processor configured to detect the gesture based on a comparison of the light intensity measured at each of the respective surface locations at two or more time instants or measurement cycles.