Parallel Electrode Touch Panel for OLED Parasitic Capacitance

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Solution Overview

Problem

Display devices with touch panels on active matrix OLEDs face increased parasitic capacitance and deteriorated time constants due to proximity of touch electrodes to anode electrodes, leading to lower sensitivity to small capacitance changes.

Innovation Solution

The implementation of a semi-in-cell type touch panel with detection electrodes and drive electrodes extending parallel to each other, separated by an insulation layer, reduces parasitic capacitance by avoiding electrode crossings and includes shield electrodes to minimize noise and virtual capacitance loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If touch electrodes are located close to the anode electrodes of OLEDs, then the touch panel can be integrated on the display panel, but parasitic capacitance increases and sensitivity to small capacitance changes deteriorates

Engineering Contradiction:

Improvetouch panel integrationVSAvoidcapacitance change detection sensitivity

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The drive electrodes are divided into multiple electrode segments in the row direction, with gaps between segments. This segmentation reduces the continuous electrode area near the anode, thereby reducing parasitic capacitance while maintaining touch detection functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Both detection electrodes and drive electrodes extend in the same direction (row direction) rather than crossing each other. This parallel arrangement in the same dimension avoids the capacitance increase caused by electrode crossings while still enabling touch detection through capacitive coupling.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If touch electrodes are located close to the anode electrodes of OLEDs, then the touch panel can be integrated on the display panel, but the time constant deteriorates

Engineering Contradiction:

Improvetouch panel integrationVSAvoidtime constant

Core Design Contradiction:

Adaptability or versatilityVSDuration of action of moving object

Solution Approach 1:

Segmenting the drive electrodes into multiple sections with gaps reduces the total electrode area in proximity to the anode, thereby reducing parasitic capacitance and shortening the time constant for faster touch response.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of having drive electrodes cross perpendicular to detection electrodes (which increases capacitance), both electrode types extend parallel in the row direction, inverting the traditional crossing arrangement to reduce capacitive coupling.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of operation

If detection electrodes and drive electrodes cross each other, then the touch detection function is achieved, but parasitic capacitance increases

Engineering Contradiction:

Improvetouch detection functionVSAvoidparasitic capacitance

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent inverts the conventional crossing electrode arrangement by having both detection and drive electrodes extend in the same direction (row direction) without crossing. This maintains capacitive coupling for touch detection while eliminating the parasitic capacitance caused by electrode intersections.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

Both electrode types are arranged to extend in the row direction, utilizing the same spatial dimension rather than crossing in perpendicular dimensions. This parallel arrangement enables touch detection through proximity-based capacitive coupling without the harmful effect of electrode crossings.

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

This configuration enhances sensitivity to small capacitance changes while preventing parasitic capacitance increases, maintaining high sensitivity and reducing the time constant deterioration.

Implementation Method 1

the parasitic capacitance increases if the touch electrodes are located close to the anodes electrode of the OLEDs

Methodology Applied

Scientific EffectParasitic capacitance: Parasitic Capacitance

Data Source

PatentUS12014013B2Display device and a method of manufacturing the same

Publication Date: 2024.06.18 SHARP KK

AI summary

A display device according to an aspect includes: a display panel; and a touch panel on the display panel. The touch panel includes: a plurality of detection electrodes extending in a first direction in a plan view; and a plurality of drive electrodes disposed respectively between the plurality of detection electrodes and extending in the first direction. Each of the plurality of drive electrodes includes: a plurality of electrode segments patterned in the first direction; and a plurality of wires connected respectively to the plurality of electrode segments and extending in the first direction.