Touch Display Parasitic Capacitance Compensation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The decreasing thickness of touch display devices leads to parasitic capacitance between sensing electrodes and the display panel, causing display noise and reducing the signal-to-noise ratio (SNR) during touch sensing.

Innovation Solution

A touch display device with a scanning driver, oscillation circuit, and sinusoidal wave signals to minimize parasitic capacitance effects by forming mutual capacitance between first and second sensing electrodes and an electrode plate, allowing for accurate touch detection while reducing noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the thickness of the touch display device is decreased, then the device becomes thinner and more compact, but parasitic capacitance increases between sensing electrodes and the display panel, causing display noise and reducing touch sensing accuracy

Engineering Contradiction:

Improvethickness of touch display deviceVSAvoidparasitic capacitance and display noise

Core Design Contradiction:

Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the harmful parasitic capacitance effect by introducing a compensation electrode that is specifically designed to counteract the parasitic capacitance between the sensing electrode and the display panel. The compensation electrode is positioned adjacent to the sensing electrode and connected to a compensation circuit that generates a compensation signal to cancel out the parasitic capacitance effect, thereby eliminating the harmful factor while maintaining the thin device structure

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a compensation electrode as an intermediary element between the sensing electrode and the display panel. This compensation electrode acts as a mediator that interacts with the parasitic capacitance to reduce its harmful effects. The compensation electrode is connected to a compensation circuit that generates a compensation signal, which serves as an intermediary signal to counterbalance the parasitic capacitance and noise, thereby improving touch sensing accuracy in thin devices

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If mutual capacitance sensing is used in a thin device, then touch sensing capability is achieved, but the parasitic capacitance causes charges to discharge in the formation direction, reducing signal amount and signal-to-noise ratio

Engineering Contradiction:

Improvetouch sensing capabilityVSAvoidsignal-to-noise ratio

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism through the compensation electrode and compensation circuit. The compensation circuit continuously monitors the parasitic capacitance effect and generates a compensation signal that is fed back to counteract the harmful effects. This feedback loop ensures that the compensation signal dynamically adjusts to maintain high signal-to-noise ratio and reliable touch sensing capability in thin devices

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent converts the harmful parasitic capacitance effect into a beneficial compensation mechanism. By introducing the compensation electrode and compensation circuit, the system uses the knowledge of parasitic capacitance to generate a compensation signal that precisely counteracts the harmful effects. The parasitic capacitance, which was previously a source of noise and signal loss, becomes a measurable parameter that enables precise compensation, thereby improving overall sensing reliability

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

The solution achieves a high signal-to-noise ratio and enables the production of thin touch display devices by minimizing parasitic capacitance and removing noise components, thereby improving touch sensing accuracy.

Implementation Method 1

a plurality of second sensing electrodes forming a mutual capacitance with the plurality of first sensing electrodes

Methodology Applied

Scientific EffectMutual capacitance: Capacitance

Implementation Method 2

a first electrode plate forming a parasitic capacitance with the first and second sensing electrodes

Methodology Applied

Scientific EffectParasitic capacitance: Parasitic Capacitance

Implementation Method 3

exchanging energy between an inductance element of the oscillation circuit and the mutual capacitance

Methodology Applied

Scientific EffectInductance: Inductor

Data Source

PatentUS9727192B2Touch display device and driving method thereof

Publication Date: 2017.08.08 SAMSUNG DISPLAY CO LTD

AI summary

A touch display device including: a plurality of first sensing electrodes; a plurality of second sensing electrodes forming a mutual capacitance with the plurality of first sensing electrodes; an oscillation circuit connected with the plurality of second sensing electrodes and supplying energy so as to generate a first sinusoidal wave signal; a first electrode plate forming a parasitic capacitance with the first and second sensing electrodes and receiving a second sinusoidal wave signal corresponding to the first sinusoidal wave signal; and a scanning driver configured to sequentially select the plurality of first sensing electrodes one-by-one, apply a reference voltage to the selected first sensing electrode, and float the first sensing electrodes which are not selected.