Floating-Electrode Capacitive Touch Panel for Touch and Pressure Detection

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Solution Overview

Problem

Capacitive touch panels with integrated pressure and position detection suffer from increased electrostatic capacitance between drive and detection electrodes, leading to prolonged response times and poor response characteristics.

Innovation Solution

Incorporating a floating electrode with a floating potential into the same layer as the detection electrodes, reducing electrostatic capacitance between the drive and detection electrodes, and using a configuration that allows for distinct capacitance changes between touch and press events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a pressure sensing electrode and position sensing electrode are formed in the same layer as the drive electrode, then both pressure and position detection functions are integrated, but the electrostatic capacitance between the drive electrode and detection electrodes increases, resulting in prolonged response time

Engineering Contradiction:

Improveintegrated pressure and position detection functionVSAvoidresponse time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The detection electrode layer is segmented into position sensing electrodes and pressure sensing electrodes with distinct spatial arrangements. Position sensing electrodes are arranged to detect touch position, while pressure sensing electrodes are arranged to detect pressure magnitude, allowing independent optimization of each detection function's electrode layout and reducing mutual interference

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A dielectric layer is introduced as an intermediary between the drive electrode and the detection electrodes in the same layer. This dielectric layer acts as an electrical insulator that prevents direct capacitive coupling, thereby reducing the parasitic electrostatic capacitance between the drive electrode and detection electrodes while still allowing the detection electrodes to sense changes in the electric field caused by touch and pressure

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the electrostatic capacitance between drive electrode and detection electrode increases, then more capacitance is available for detection, but the time constant of the drive signal increases, degrading response characteristics

Engineering Contradiction:

Improvedetection capabilityVSAvoidresponse speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrode design employs local quality by creating regions of high capacitance change sensitivity specifically at the touch and pressure detection zones. The position sensing electrodes and pressure sensing electrodes are strategically positioned and shaped to maximize capacitance change in their respective detection regions, ensuring reliable detection without requiring uniformly high capacitance across the entire electrode structure

Inventive Principle:

Principle #3Local quality

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

Prevents the increase in electrostatic capacitance between the drive and detection electrodes, enabling faster and more accurate detection of touch and pressure, with improved signal intensity differentiation.

Implementation Method 1

an electrostatic capacitance is formed between the drive electrode and the position sensing electrode, and additionally between the drive electrode and the pressure sensing electrode

Methodology Applied

Scientific EffectElectrostatic capacitance: Capacitance

Implementation Method 2

a pointing object is capacitively coupled to the drive electrode and the position sensing electrode. As a result, an electrostatic capacitance between the drive electrode and the position sensing electrode decreases

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentUS12417000B2Capacitive touch panel and display device

Publication Date: 2025.09.16 SHARP DISPLAY TECHNOLOGY CORP

AI summary

A touch panel includes: a drive electrode supplied with a drive signal; a position detecting electrode detecting a position included in a touch surface and touched with a pointing object, and a pressure detecting electrode detecting pressure applied on the touch surface with the pointing object, the position detecting electrode and the pressure detecting electrode being disposed across the drive electrode from the touch surface; and a floating electrode having a floating potential. The position detecting electrode, the pressure detecting electrode, and the floating electrode are formed in a layer.