Resistive Touch Panel Multi-Touch Detection via Anisotropic Conductive Films

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Solution Overview

Problem

Conventional resistive touch panels lack multi-touch detection capability, and while capacitive touch panels can support multi-touch, their manufacturing processes are complex and detection methods are intricate.

Innovation Solution

A resistive multi-touch touch panel utilizing two conductive films with electric anisotropy, where voltages are applied and measured at specific points to determine the locations of touched points, allowing for accurate detection of multiple touches through a simplified method.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a capacitive type touch panel is used to support multi-touch detection, then multi-touch detection capability is improved, but the manufacturing process complexity and detection method complexity increase

Engineering Contradiction:
Improvemulti-touch detection capabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by utilizing conductive films with different resistivity characteristics. Specifically, the first conductive film has higher resistivity than the second conductive film, creating a voltage divider effect that enables multi-touch detection through voltage measurements. This parameter-based differentiation allows the resistive touch panel to achieve multi-touch capability without requiring complex manufacturing processes or additional electrode structures.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If a capacitive type touch panel is used to support multi-touch detection, then multi-touch detection capability is improved, but the detection method complexity increases

Engineering Contradiction:
Improvemulti-touch detection capabilityVSAvoiddetection method complexity
Core Design Contradiction:
Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces complex electrical measurement systems with a simpler voltage-based detection method. By using the inherent voltage divider effect created by two conductive films with different resistivities, the system determines touch locations through straightforward voltage measurements rather than complex capacitive sensing algorithms. This substitution simplifies the detection method while maintaining multi-touch capability.

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

3Ease of manufacture

If conventional resistive type touch panel is used, then manufacturing process simplicity is maintained, but multi-touch detection capability is lost

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidmulti-touch detection capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent employs composite materials by combining two conductive films with different resistivity properties in a single touch panel structure. The first conductive film (higher resistivity) and the second conductive film (lower resistivity) work together to create a voltage divider system. This composite structure enables multi-touch detection while maintaining the manufacturing simplicity of resistive touch panels, as both films can be deposited using conventional sputtering processes.

Inventive Principle:
Principle #40Composite materials

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 accurate detection of multiple touch points with a simplified process, improving the multi-touch functionality of resistive touch panels and reducing the complexity of capacitive panel manufacturing methods.

Implementation Method 1

a first conductive film which exhibits electric anisotropy, has a lower resistivity in a first direction than that in a second direction

Methodology Applied
Scientific EffectElectric anisotropy: Anisotropy

Data Source

PatentEP2275911B1Touch panel and multi-touch detecting method thereof
Publication Date: 2016.12.14 INNOLUX CORP
  • EP2275911B1 patent drawingFigure 1
  • EP2275911B1 patent drawingFigure 2
  • EP2275911B1 patent drawingFigure 3

AI summary

A multi-touch detecting method is adapted for detecting locations of touched points on a touch panel including first and second conductive films (113, 123), and includes following steps. Measuring points of the first conductive film distributed along X-axis of a Cartesian plane are scanned, and x-components (X1, X2, X3) are determined accordingly. Measuring points of the second conductive film distributed along Y-axis of the Cartesian plane are scanned, and y-components are determined accordingly (Y1, Y2, Y3). A first voltage is applied to the first conductive film, and a second voltage is applied to at least one of the second measuring points with the location on the Y-axis adjacent to or overlapping one of the y-components. Voltages at the first measuring points with the locations on the X-axis adjacent to or overlapping the x-components are measured sequentially and one of the y-components and one of the x-components are outputted.