Optical Depression Sensor for False Touch Reduction

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Solution Overview

Problem

Portable electronic devices with touch-sensitive displays face challenges in accurately distinguishing between true and false touches, especially due to contaminants and noise, which can lead to unintended selections and reduced user experience.

Innovation Solution

Incorporating a depression sensor, such as a mechanical actuator or piezoelectric actuators, that provides tactile feedback and utilizes optical depression sensors to detect force thresholds on the touch-sensitive display, allowing for reliable selection confirmation and reducing false touches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a touch-sensitive display is used to reduce device size and improve portability, then ease of operation and space efficiency are improved, but reliability deteriorates due to false touches caused by contaminants and noise

Engineering Contradiction:
Improvedisplay sizeVSAvoidtouch accuracy
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent introduces a depression sensor as an intermediary component between the touch-sensitive display and the selection confirmation process. This sensor detects actual depression events (through mechanical actuation or piezoelectric effects) and provides a separate confirmation signal, acting as a mediator that filters out false touches from the optical or capacitive touch sensor while still allowing valid user inputs to be registered.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces or supplements the purely optical/capacitive touch detection system with a mechanical or piezoelectric depression detection system. The mechanical actuator or piezoelectric actuator provides a physical sensing mechanism that is less susceptible to false triggers from contaminants, offering a more reliable method for confirming user selection intent.

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

2Reliability

If a secondary sensor is added to confirm touches and reduce false inputs, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvetouch confirmation accuracyVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The depression sensor serves multiple functions: it detects user depression events, provides tactile feedback through mechanical or piezoelectric actuation, and generates selection confirmation signals. By combining these functions in a single component, the patent avoids the need for separate sensors for each function, thereby reducing overall system complexity while still improving reliability.

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

Solution Approach 2:

The depression sensor utilizes the user's own depression action as both the input signal and the confirmation mechanism. When the user depresses the display, the same mechanical or piezoelectric effect that detects the depression also provides tactile feedback and generates the selection signal, eliminating the need for additional complex confirmation mechanisms.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If tactile feedback is provided through mechanical actuators to confirm selection, then ease of operation is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveuser feedback qualityVSAvoidactuator integration complexity
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent combines the depression detection function and the tactile feedback function into a single mechanical or piezoelectric actuator system. The same component that detects the user's depression input also provides the tactile feedback, merging two functions into one element and simplifying the manufacturing process compared to using separate detection and feedback mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent utilizes changes in mechanical or piezoelectric parameters (such as resistance, capacitance, or physical deformation) that occur naturally during the depression process. By detecting these parameter changes and using the same parameter changes to drive tactile feedback, the system achieves enhanced ease of operation without requiring complex additional components or manufacturing processes.

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 user experience by providing accurate selection confirmation and reducing unintended inputs through the use of tactile and visual feedback, improving the reliability of touch interactions on portable electronic devices.

Implementation Method 1

One or more optical signals are emitted towards the touch-sensitive display by the optical device. The reflected optical signals are evaluated for a change in reflection to determine whether the touch-sensitive display is depressed.

Methodology Applied
Scientific EffectOptical reflection: Reflection

Implementation Method 2

Incorporating a depression sensor, such as a mechanical actuator or piezoelectric actuators, that provides tactile feedback and utilizes optical depression sensors to detect force thresholds on the touch-sensitive display

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2439619B1Touch-sensitive display with optical sensor and method
Publication Date: 2019.07.17 BLACKBERRY LTD
  • EP2439619B1 patent drawingFigure 1
  • EP2439619B1 patent drawingFigure 2~4
  • EP2439619B1 patent drawingFigure 5~7

AI summary

An electronic 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 an optical device that receives a reflection of an optical signal, wherein the force affects the reflection.