Touch Panel Multi-Point Pressing Force Detection

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Solution Overview

Problem

Existing touch panel devices struggle to detect pressing forces during multi-touch inputs, particularly when two points are pressed simultaneously, as single sensors are inadequate and using multiple sensors increases manufacturing costs and complexity.

Innovation Solution

A touch panel device with resistive films and a control unit that includes voltage detection units to differentiate between single and multi-point contacts, allowing for the detection of pressing forces at two points by measuring voltage changes across electrodes, thereby determining contact coordinates and forces without the need for complex sensor control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single sensor for detecting the pressing force is used, then the manufacturing cost is low, but the sensor cannot detect which of the two points of the touch panel is pressed strongly

Engineering Contradiction:
Improvemanufacturing costVSAvoidpressing force detection accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical pressure sensors with an electrical measurement system. By applying voltage to electrodes and measuring voltage differences at contact points, the system detects pressing forces through electrical properties rather than mechanical sensing. This substitution enables multi-point pressing force detection using a single control unit, achieving both low cost and high measurement precision.

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

2Measurement precision

If a plurality of sensors are used to detect pressing forces at multiple points, then the detection accuracy is improved, but the manufacturing cost increases and complex control processing is required

Engineering Contradiction:
Improvepressing force detection accuracyVSAvoidsensor control complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control unit is designed to perform multiple functions: it applies voltage to electrodes, measures voltage differences, calculates contact point coordinates, and determines pressing forces. This multi-functional design eliminates the need for separate sensors at each contact point, reducing device complexity while maintaining the ability to detect pressing forces at multiple points simultaneously.

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

Solution Approach 2:

The touch panel surface itself serves as the sensing element. When users press on the touch panel, the contact points create electrical connections that the control unit detects through voltage measurements. The system uses the touch panel's own structure and the users' pressing actions to generate the measurement signals, eliminating the need for external sensing components.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If a plurality of sensors are used to detect pressing forces at multiple points, then the detection accuracy is improved, but the manufacturing cost increases

Engineering Contradiction:
Improvepressing force detection accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces mechanical pressure sensors with an electrical measurement system. By applying voltage to electrodes and measuring voltage differences at contact points, the system detects pressing forces through electrical properties rather than mechanical sensing. This substitution enables multi-point pressing force detection using a single control unit, achieving both low cost and high measurement precision.

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

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

Enables easy detection of pressing forces during multi-touch inputs at a lower cost by simplifying the detection process and determining which points are pressed more forcefully, improving user interaction and device operability.

Implementation Method 1

a first resistive film 10 and a second resistive film 20 which are arranged opposite to each other

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP3531255B1Touch panel device
Publication Date: 2022.12.07 FCL COMPONENTS LTD
  • EP3531255B1 patent drawingFigure 1A~1B
  • EP3531255B1 patent drawingFigure 2
  • EP3531255B1 patent drawingFigure 3A~3D

AI summary

A CPU 31 of a touch panel device 100 controls a plurality of switches so as to apply a voltage to an XL electrode 14 and ground a YH electrode 22, measures a voltage difference between an XH electrode 12 and a YL electrode 24 as a first pressing force (step S11), controls the plurality of switches so as to apply a voltage to the XH electrode 12 and ground the YL electrode 24, measures a voltage difference between the XL electrode 14 and the YH electrode 22 as a second pressing force (step S11), associates the first pressing force and the second pressing forces with coordinates of two points, respectively, and outputs the associated data to the computer 40 (step S12).