Multi-Touch Position Detection Using Coordinate Filtering

Solution Overview

Problem

Conventional capacitive-type touch panels struggle to accurately detect multiple touch positions, leading to inaccuracies and limitations in user input, particularly when detecting coordinates of actual versus virtual touch positions.

Innovation Solution

A method involving periodic scanning of the touch panel, recording and comparing coordinates over time intervals to differentiate between actual and virtual touch positions, ensuring accurate detection of multiple touch points by removing coordinates that match previously recorded positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional capacitive-type touch panel detection method is used, then the touch panel can detect touch positions, but the accuracy of detecting multiple touch positions is poor and virtual touch positions are incorrectly identified

Engineering Contradiction:

Improvetouch position detection accuracyVSAvoiddetection result reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary recording of touch position coordinates when a touch is first detected. This preliminary action creates a reference database of actual touch positions that is used later to filter out virtual touch positions, thereby improving detection accuracy and reliability of multiple touch positions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by comparing newly detected touch positions against previously recorded coordinates. When new touch positions are detected, the system checks whether they match existing recorded positions and removes duplicates, creating a feedback loop that continuously refines detection accuracy and eliminates false readings

Inventive Principle:

Principle #23Feedback

2Ease of operation

If conventional scanning method is used, then the touch panel can operate continuously, but it cannot differentiate between actual and virtual touch positions

Engineering Contradiction:

Improveuser input accuracyVSAvoidcoordinate processing complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The system performs preliminary recording of touch position coordinates when a touch is first detected. This preliminary action creates a reference database of actual touch positions that is used later to filter out virtual touch positions, thereby improving detection accuracy and reliability of multiple touch positions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by comparing newly detected touch positions against previously recorded coordinates. When new touch positions are detected, the system checks whether they match existing recorded positions and removes duplicates, creating a feedback loop that continuously refines detection accuracy and eliminates false readings

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS8305357B2Method for detecting multiple touch positions on a touch panel

Publication Date: 2012.11.06 SAMSUNG DISPLAY CO LTD

AI summary

A method for detecting multiple touch positions on a touch panel includes the steps of: periodically scanning the touch panel; when detecting a first touch position at a first time during scanning the touch panel, recording coordinates on a first dimensional direction and a second dimensional direction of the first touch position; continuingly scanning the touch panel after the first time; and when detecting a plurality of new possible touch positions at a second time, determining a second touch position from the new possible touch positions according to the recorded coordinates on the first and second dimensional directions of the first touch position.