Capacitive Optical Touch Screen Display System

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Solution Overview

Problem

Optical touch screen devices suffer from long delay times in detecting and determining touch occurrences, leading to user interaction issues and potential erroneous selections due to complex detection methods.

Innovation Solution

A touch screen display system combining a capacitive touch-sensor assembly for detecting touch occurrences and an optical touch-sensor assembly for determining touch locations, with a processor connected to both, allowing for rapid and accurate input determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If optical touch-sensor assembly is used to detect touch occurrence, then touch location can be determined, but long delay time results from complex detection methods

Engineering Contradiction:
Improvetouch location determinationVSAvoidresponse time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The touch detection process is divided into two separate assemblies: a capacitive touch-sensor assembly for detecting touch occurrence and an optical touch-sensor assembly for determining touch location. This segmentation allows each assembly to specialize in its specific function, with the capacitive sensor providing rapid touch detection and the optical sensor providing precise location determination, thereby reducing overall response time while maintaining measurement precision.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If complex detection methods are used to determine touch location, then accurate touch location can be determined, but long delay time results

Engineering Contradiction:
Improvetouch location accuracyVSAvoiddetection method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines two different sensing technologies (capacitive and optical touch-sensor assemblies) into a unified touch screen display system. The capacitive assembly detects touch occurrence through electrical field changes, while the optical assembly determines location through light interaction. This merging of technologies allows for accurate touch location determination using methods that are less complex and faster than traditional single-system approaches.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If optical touch-sensor assembly is used, then touch location can be determined, but additional or erroneous user-selection may occur during waiting period

Engineering Contradiction:
Improvetouch location determinationVSAvoiduser input accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The capacitive touch-sensor assembly performs preliminary action by detecting touch occurrence first, which then triggers the optical touch-sensor assembly to determine the precise touch location. This preliminary detection allows the system to prepare for location determination in advance, reducing the waiting period and minimizing the chance of additional or erroneous user selections during the response time.

Inventive Principle:
Principle #10Preliminary action

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 combination reduces response time and minimizes erroneous inputs by determining touch locations quickly, enhancing user interaction and reducing the likelihood of additional or incorrect user selections.

Implementation Method 1

a capacitive touch-sensor assembly at the display device for detecting a touch occurrence on the display device

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

an optical touch-sensor assembly at the display device for determining a location of the touch occurrence on the display device

Methodology Applied
Scientific EffectOptical detection:

Data Source

PatentEP2105824B1Touch screen display for electronic device and method of determining touch interaction therewith
Publication Date: 2013.03.20 BLACKBERRY LTD
  • EP2105824B1 patent drawingFigure 1
  • EP2105824B1 patent drawingFigure 2
  • EP2105824B1 patent drawingFigure 3

AI summary

A touch screen display system for use in an electronic device includes a display device, a capacitive touch-sensor assembly disposed on the display device for detecting a touch occurrence on the display, and an optical touch-sensor assembly at the display device for determining a location of the touch occurrence at the display in response to the capacitive touch-sensor assembly detecting the touch occurrence on the display.