Concave Touch Electrodes for Hover Sensing Accuracy

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Solution Overview

Problem

Existing touch sensors face challenges in efficiently detecting coordinates of a detection target not contacting the screen, due to difficulties in forming an electric field several centimeters away, which affects the accuracy of hover sensing techniques.

Innovation Solution

The implementation of a touch or proximity sensor with a configuration of first and second touch electrodes extending in intersecting directions, where at least one of each type has a concave surface on the detection surface, enhancing the surface area and directing electric lines of force inward to improve detection sensitivity and accuracy for targets both contacting and spaced apart from the screen.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional flat touch electrode is used, then the device structure is simple, but the detection sensitivity for hover sensing (non-contact sensing) is insufficient due to difficulty in forming an electric field several centimeters away

Engineering Contradiction:

Improvedetection sensitivityVSAvoidelectrode structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The touch electrode is designed with a concave curved surface instead of a flat surface. This curvature concentrates the electric field lines toward the center of the electrode, extending the electric field several centimeters away from the electrode surface. The concave shape creates a focal point effect that enhances the detection sensitivity for hover sensing applications while maintaining a relatively simple electrode structure.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Length of stationary object

If the touch electrode surface area is increased to improve electric field formation, then the detection range is extended, but the device size and complexity increase

Engineering Contradiction:

Improveelectric field extension distanceVSAvoidelectrode configuration complexity

Core Design Contradiction:

Length of stationary objectVSDevice complexity

Solution Approach 1:

The concave curved surface of the electrode creates a focusing effect that concentrates electric field lines, allowing the electric field to extend several centimeters away without requiring a large electrode area. This curvature design achieves extended detection range while maintaining a compact device structure.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The electrode surface geometry is changed from flat to concave curved, which fundamentally alters the electric field distribution pattern. This parameter change in surface shape enables the electric field to extend farther without increasing the physical electrode dimensions or device complexity.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If a concave surface is added to the touch electrode to concentrate electric fields, then the detection sensitivity is improved, but the manufacturing process becomes more complex

Engineering Contradiction:

Improvehover sensing accuracyVSAvoidelectrode fabrication difficulty

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The concave curved surface can be formed using standard semiconductor fabrication techniques such as reflow processing or molding during the electrode formation step. While slightly more complex than flat electrodes, the manufacturing process remains within conventional capabilities and achieves significant improvement in hover sensing accuracy.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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

This configuration increases the number of electric fields and improves detection sensitivity and accuracy for targets both in contact with and spaced apart from the screen, enhancing the detection of coordinates projected onto the touch panel.

Implementation Method 1

the difficulty of efficiently forming an electric field up to the finger spaced approximately several centimeters apart from a touch sensor makes the hover sensing difficult

Methodology Applied

Scientific EffectElectric Field: Electric Field

Implementation Method 2

a capacitance between a touch electrode on a display surface and a finger spaced approximately several centimeters apart therefrom is detected

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10444880B2Touch or proximity sensor and display device

Publication Date: 2019.10.15 MAGNOLIA WHITE CORP

AI summary

There is provided a touch or proximity sensor including a plurality of first touch electrodes extending in a first direction and being arranged in a second direction intersecting the first direction, and a plurality of second touch electrodes extending in the second direction, being arranged in the first direction, and insulated from the plurality of first touch electrodes, in which at least one of the plurality of first touch electrodes and at least one of the plurality of second touch electrodes respectively have concave surface on a detection surface side.