Synchronized Multi-Touch Screen Scanning for Edge Detection

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Solution Overview

Problem

Existing touch screen systems face challenges in efficiently detecting simultaneous touches across multiple touch detection screens, particularly in accurately identifying touches that span across the edges of adjacent screens, leading to potential misinterpretation of multi-touch inputs.

Innovation Solution

Implementing a master-slave configuration between touch screen controllers, where a master touch screen controller synchronizes the scanning of neighboring row lines with a slave touch screen controller, ensuring simultaneous and synchronized scanning to accurately detect touches across multiple screens.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If independent scanning of multiple touch detection screens is used, then device complexity is reduced, but measurement precision deteriorates due to inability to accurately detect simultaneous touches across screen edges

Engineering Contradiction:
Improvetouch detection accuracyVSAvoidcontroller coordination complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the scanning operations of multiple independent touch detection screens into a coordinated master-slave system. The master controller scans row lines of its screen while the slave controller synchronously scans corresponding row lines of the slave screen, combining their detection capabilities to accurately identify touches spanning across screen boundaries.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The slave touch detection controller receives timing signals from the master controller and uses this feedback to synchronize its scanning operation. This ensures that both controllers scan at the same rate and in the same sequence, enabling accurate detection of simultaneous touches across multiple screens without requiring complex independent coordination.

Inventive Principle:
Principle #23Feedback

2Reliability

If synchronized scanning across multiple screens is implemented, then reliability of multi-touch detection is improved, but device complexity increases due to master-slave controller configuration

Engineering Contradiction:
Improvesimultaneous touch detection reliabilityVSAvoidcontroller configuration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the control function by designating one controller as master and others as slaves. Each slave controller operates independently but is coordinated through timing signals from the master, dividing the complexity of synchronized scanning across multiple screens into manageable segments while maintaining overall reliability.

Inventive Principle:
Principle #1Segmentation

3Productivity

If sequential scanning of touch screens is used, then device complexity is minimized, but loss of time increases due to inability to detect simultaneous touches across multiple screens

Engineering Contradiction:
Improvetouch detection speedVSAvoidscan timing coordination time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent implements periodic synchronized scanning where the master controller initiates scanning cycles and slave controllers follow at regular intervals. This periodic action enables simultaneous detection across multiple screens without requiring complex real-time coordination, maintaining high detection speed while minimizing timing coordination overhead.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2480952B1Touch detection
Publication Date: 2018.11.21 NOKIA TECHNOLOGIES OY
  • EP2480952B1 patent drawingFigure 1a~2
  • EP2480952B1 patent drawingFigure 3~4
  • EP2480952B1 patent drawingFigure 5

AI summary

An apparatus with a first and second touch screen, where the first touch screen has a plurality of first touch sensors formed as a first grid of rows and columns and the second touch screen has a plurality of second touch sensors formed as a second grid of rows and columns. A first processor detects touch areas by scanning through the first touch sensors in a predetermined order along the rows and columns. A second processor detects touch areas by scanning through the second touch sensors in a predetermined order along the rows and columns. A controller causes that the first and second processors scan the first and second grids synchronized such that when the first and second touch screens are arranged side by side, neighboring first and second touch sensors are scanned substantially simultaneously.