Hybrid Optical-Physical Touch Screen Validation

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Solution Overview

Problem

Existing touch screens, particularly optical touch screens, face challenges in distinguishing between intentional physical touch events and vibrations or false triggers in harsh environments like airborne platforms, leading to premature detection issues.

Innovation Solution

A hybrid optical-physical touch screen system that combines optical sensors with physical touch sensors to validate intentional touch events by comparing spatial location and physical touch signals using predefined parameters, with physical touch sensors positioned along the circumference to avoid image degradation and differentiate between touch events and vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If optical sensors are used to detect touch events, then touch detection capability is improved, but false detection of vibrations increases

Engineering Contradiction:
Improvetouch detection capabilityVSAvoidfalse detection rate
Core Design Contradiction:
Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The patent combines optical sensors with physical touch sensors (piezoelectric, capacitive, or resistive) into a hybrid touch screen system. The optical sensors detect the position of the physical object, while the physical touch sensors detect actual contact with the display. By merging these two sensing mechanisms, the system achieves both high touch detection capability and reliable distinction between intentional touches and environmental vibrations.

Inventive Principle:
Principle #5Merging (Combining)

2Difficulty of detecting and measuring

If physical touch sensors are placed on transparent layer, then touch sensitivity is improved, but image quality degrades

Engineering Contradiction:
Improvetouch sensitivityVSAvoidimage quality
Core Design Contradiction:
Difficulty of detecting and measuringVSIllumination intensity

Solution Approach 1:

The patent segments the touch sensing function into two parts: optical sensors positioned along the circumference of the display that detect touch position without degrading image quality, and physical touch sensors that detect actual contact. By placing optical sensors at the edges rather than across the entire display surface, the system maintains high image quality while preserving touch sensitivity through the combination of both sensor types.

Inventive Principle:
Principle #1Segmentation

3Speed

If optical touch plane is displaced from actual screen, then early touch detection is achieved, but premature touch event detection occurs

Engineering Contradiction:
Improvetouch detection timingVSAvoidtouch event accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the optical sensors provide preliminary detection of touch position, and this information is used to activate or adjust the physical touch sensors at the corresponding location. The physical touch sensors then provide confirmation of actual contact. This feedback loop allows the system to maintain early detection capability while ensuring accurate touch event recognition through sequential verification.

Inventive Principle:
Principle #23Feedback

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

Effectively reduces false triggers by confirming intentional touch events, maintaining high image quality and accurately distinguishing between touch events and environmental vibrations.

Implementation Method 1

optical sensors positioned along a circumference of the electronic panel display and configured to determine a spatial location of a physical object

Methodology Applied
Scientific EffectOptical imaging: Reflection

Implementation Method 2

a plurality of physical touch sensors coupled to the electronic panel display and configured to detect physical touch signals applied by the physical object to the electronic panel display

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2893424B1Validating a physical touch event in optical touch screens
Publication Date: 2020.12.30 ELBIT SYSTEMS LTD
  • EP2893424B1 patent drawingFigure 1~2
  • EP2893424B1 patent drawingFigure 3A~3B

AI summary

A hybrid optical-physical touch screen is provided herein. The touch screen includes: an electronic panel display; one or more optical sensors coupled to the electronic panel display and configured to determine, a spatial location of a physical object on an X-Y plane near the electronic panel display; a plurality of physical touch sensors coupled to the electronic panel display and configured to determine, a physical touch event between the physical object and the electronic panel display; and a processor configured to compare the determined spatial location of the physical object with the determined physical touch event between the physical object and the display at a same time, and determine, based on predefined parameters, whether an intentional physical touch event between the physical object and the electronic panel display has occurred.