Touch Sensor Edge Electrodes for Effective Area Expansion

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Solution Overview

Problem

Existing touch sensor devices have limited effective sensing areas, leading to wasted space and increased costs due to inefficient use of available space, particularly in small electronic devices.

Innovation Solution

The implementation of an edge electrode set that surrounds the perimeter of sensing electrodes to increase the effective sensing area, enhancing space efficiency with a minimal increase in device complexity and size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If the effective sensing area is limited to the region inside the center of the outermost electrodes, then the device complexity is reduced, but the space efficiency and effective area are wasted

Engineering Contradiction:

Improveeffective sensing areaVSAvoiddevice complexity

Core Design Contradiction:

Area of moving objectVSDevice complexity

Solution Approach 1:

The electrode structure is segmented into two distinct parts: sensing electrodes for detecting touch input and edge electrodes for extending the effective sensing area. This segmentation allows each electrode type to serve its specific function optimally, resolving the contradiction by enabling area expansion without proportionally increasing overall complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The edge electrodes serve multiple functions: they extend the effective sensing area beyond the traditional limits, provide structural boundary definition, and maintain electrical field distribution. This multi-functionality allows area expansion without requiring separate dedicated components for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Area of moving object

If the effective sensing area is expanded beyond the traditional electrode region, then space efficiency improves, but the physical area and device size increase

Engineering Contradiction:

Improveeffective sensing areaVSAvoidphysical area

Core Design Contradiction:

Area of moving objectVSArea of stationary object

Solution Approach 1:

The edge electrodes are positioned along the perimeter boundary of the sensing electrode array, utilizing the dimensional space around the existing electrodes rather than expanding the overall device footprint. This allows the effective sensing area to extend into previously unused peripheral regions without proportionally increasing the physical device area

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Area of moving object

If more electrodes are added to increase effective area, then the sensing coverage improves, but the manufacturing complexity and cost increase

Engineering Contradiction:

Improveeffective sensing areaVSAvoidease of manufacture

Core Design Contradiction:

Area of moving objectVSEase of manufacture

Solution Approach 1:

Instead of adding electrodes throughout the entire sensing area, the invention applies edge electrodes only at the perimeter regions where sensing extension is most beneficial. This partial action approach achieves effective area expansion with minimal additional electrode count, reducing manufacturing complexity compared to comprehensive electrode coverage

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS7656392B2Touch sensor effective area enhancement

Publication Date: 2010.02.02 WACOM CO LTD

AI summary

A touch sensor device is provided that that uses an edge electrode set to provide an improved effective area. Specifically, the touch sensor device includes an edge electrode set that together substantially surround a perimeter of sensing. The edge electrode set increases the effective sensing area of the touch sensor device, and thus can be used to improve the space efficiency of the touch sensor device.