Optical Depression Sensing for Touch Displays

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Solution Overview

Problem

Portable electronic devices with touch-sensitive displays face challenges in accurately detecting force inputs due to their small size and limited space, leading to potential unintended selections and a need for improved input accuracy.

Innovation Solution

The implementation of optical depression sensing arrangements using optical carriers and emitters/detectors to detect changes in optical paths, phases, and amplitudes, which trigger selection options and provide tactile feedback, replacing or complementing mechanical and piezoelectric actuators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical actuators are used for depression detection, then tactile feedback can be provided, but the device size increases and complexity increases

Engineering Contradiction:

Improvedepression detection accuracyVSAvoidactuator mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical actuators with optical detection components. Specifically, optical carriers (light sources and detectors) are used to detect depression of the touch-sensitive display by measuring changes in optical path length, eliminating the need for complex mechanical actuator mechanisms while maintaining depression detection capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces optical carriers as intermediary elements between the touch-sensitive display and the detection system. The optical carriers (light sources and detectors) mediate the detection process by converting mechanical depression into optical signal changes, providing a non-mechanical means of detection

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If mechanical actuators are used for depression detection, then tactile feedback can be provided, but the device becomes more susceptible to liquid and corrosion

Engineering Contradiction:

Improvedepression detection accuracyVSAvoidliquid and corrosion susceptibility

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical actuators with optical detection components that are sealed and isolated from the environment. The optical carriers (light sources and detectors) are positioned behind the touch-sensitive display, creating a sealed optical path that is resistant to liquid and corrosion, eliminating the vulnerability of mechanical components to environmental factors

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The optical carriers serve as intermediaries that are isolated from direct contact with the environment. The optical detection system is positioned behind the display, using light as a mediator to detect depression without requiring exposed mechanical components, thereby providing resistance to liquid and corrosion

Inventive Principle:

Principle #24Intermediary (Mediator)

3Volume of moving object

If the touch-sensitive display size is decreased for portability, then device portability is improved, but input accuracy deteriorates

Engineering Contradiction:

Improvedevice sizeVSAvoidforce input detection accuracy

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent uses optical detection components (optical carriers) that can be integrated into small form factors. The optical system allows for precise measurement of depression force and location even on small displays, as optical detection can achieve high precision without requiring large mechanical measurement components

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from mechanical displacement to optical path length changes. This allows for highly sensitive detection of small forces and displacements on compact displays, as optical detection can measure extremely small changes in path length, thereby maintaining high measurement precision in small devices

Inventive Principle:

Principle #35Parameter 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

Enhances input accuracy by reliably detecting force thresholds on touch-sensitive displays, reducing unintended selections, and providing tactile feedback, while maintaining a compact device design resistant to liquid and corrosion.

Implementation Method 1

An optical emitter of the depression sensor directs optical signals into one or more optical carriers

Methodology Applied

Scientific EffectOptical signal propagation: Light

Implementation Method 2

The optical signals are evaluated to determine whether the touch-sensitive display has been depressed

Methodology Applied

Scientific EffectOptical detection: Photoelectric Effect

Data Source

PatentUS9223431B2Touch-sensitive display with depression detection and method

Publication Date: 2015.12.29 MALIKIE INNOVATIONS LTD

AI summary

A device includes a touch-sensitive display and a sensor configured to detect a force that results in depression of the touch-sensitive display. The sensor includes one or more wavelength selective optical carriers that carry optical signals. The force affects one or more optical paths of the optical signals.