Side Surface Electrode Capacitive Coupling for Touch Detection

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Solution Overview

Problem

Existing touch panel devices on portable terminals struggle to accurately detect touches on side surfaces without increasing production costs or electric power consumption, and require complex control systems and larger display sizes, which compromises operability and design aesthetics.

Innovation Solution

A touch-panel-equipped display device with side surface electrodes that are capacitively coupled with Y-direction electrodes on the touch panel, allowing for accurate touch detection without additional expensive sensors, using a configuration where the side surface electrodes are separated from the Y-direction electrodes to enable capacitive coupling and simplify controlling operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pressure sensors are used on the side surface, then touch detection is enabled, but the device cannot detect soft touches and requires significant pressing force

Engineering Contradiction:

Improvetouch detection sensitivityVSAvoidtouching force requirement

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces mechanical pressure sensors with an electrostatic capacitance-based touch sensor system. The side surface electrode detects touches through capacitance changes caused by the proximity of conductive objects (fingers), eliminating the need for mechanical pressure detection and enabling detection of soft touches without requiring significant pressing force.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from mechanical pressure to electrostatic capacitance. By measuring capacitance changes between the side surface electrode and the touch object, the system achieves high sensitivity for soft touches while maintaining ease of operation, as capacitance changes occur even with minimal finger proximity.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If multiple light sensors are provided to improve touch detection accuracy, then detection accuracy improves, but production costs and electric power consumption increase

Engineering Contradiction:

Improvetouch detection accuracyVSAvoidnumber of sensors

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent makes the touch panel's Y-direction electrode part serve dual functions: it detects touches on the display surface and simultaneously detects touches on the side surface through capacitive coupling. This eliminates the need for separate side surface sensors, reducing the total number of sensors while maintaining high detection accuracy.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the side surface touch detection function with the existing touch panel electrode structure. The Y-direction electrode part acts as both the touch detection electrode for the display surface and the capacitive coupling element for side surface detection, consolidating multiple functions into a single component.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If touch panels are provided on side surfaces to detect hand states, then various states can be detected, but the display surface area decreases due to widened outer edge parts

Engineering Contradiction:

Improvehand state detection capabilityVSAvoiddisplay surface area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent detects side surface touches by utilizing the electric field extension in the third dimension (perpendicular to the touch panel surface). The Y-direction electrode part detects capacitance changes caused by side surface touches through its electric field, eliminating the need for physical side surface touch panels and preserving the full display surface area.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 high-accuracy touch detection on side surfaces with a simple controlling operation, reducing the need for additional hardware and maintaining a compact display size, thus improving operability and design aesthetics.

Implementation Method 1

the side surface electrode part can be electrically connected by capacitive coupling with the Y-direction electrode part on the touch panel

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentUS10180761B2Touch-panel-equipped display device including side surface electrodes

Publication Date: 2019.01.15 SHARP KK

AI summary

Provided is a touch-panel-equipped display device that is capable of detecting a touch on a side surface of a case (1) at a high accuracy by a simple controlling operation, without any hardware such as expensive sensors being provided additionally. In the touch-panel-equipped display device, a side surface electrode part can be electrically connected by capacitive coupling with a Y-direction electrode part. A change in capacitive coupling when the side surface electrode part is touched by a finger or the like, therefore, is reflected in a sense signal acquired by the Y-direction electrode part. In other words, in the touch-panel-equipped display device, a touch on the side surface electrode part can be detected using the sense signal. The touch-panel-equipped display device, therefore, is capable of detecting a touch on the side surface electrode part by using hardware and signal processing for touch detection in a conventional touch panel.