Touch Circuit Charge Control Parasitic Capacitance Compensation

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Solution Overview

Problem

Conventional touch sensing devices experience reduced touch sensitivity due to parasitic capacitance occurring inside or outside the touch screen panel, which affects the accuracy of touch detection and position identification.

Innovation Solution

A touch circuit with a charge control circuit that adjusts the electric charge input to a preamplifier, reducing or eliminating the influence of parasitic capacitance by controlling the charge quantity, thereby improving sensing accuracy and noise reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If capacitance-based touch sensing is used to detect touch position, then touch input capability is provided, but parasitic capacitance reduces touch sensitivity and sensing accuracy

Engineering Contradiction:

Improvetouch input capabilityVSAvoidtouch sensing accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary anti-action by introducing a charge control circuit that proactively compensates for parasitic capacitance effects before they degrade sensing accuracy. The circuit predicts and counteracts the parasitic capacitance influence through controlled charge injection or removal, thereby maintaining touch sensing precision without sacrificing capacitance-based touch input capability

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent converts the harmful parasitic capacitance into a beneficial effect by using the charge control circuit to measure and utilize the parasitic capacitance value. The circuit intentionally charges or discharges capacitors to match the parasitic capacitance, thereby transforming the harmful interference into a compensatable parameter that improves overall sensing accuracy

Inventive Principle:

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

2Ease of operation

If touch driving patterns are driven to enable touch sensing, then touch detection function is achieved, but parasitic capacitance is generated between driving patterns and neighboring conductors

Engineering Contradiction:

Improvetouch detection functionVSAvoidparasitic capacitance

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a charge control circuit as an intermediary between the touch driving patterns and the sensing system. This intermediary circuit measures the parasitic capacitance generated by the driving patterns and applies compensatory charge control, thereby mediating the harmful interaction between driving patterns and neighboring conductors while preserving the touch detection function

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If conventional touch sensing is used without charge control, then circuit structure remains simple, but sensing data contains noise components and lacks accuracy

Engineering Contradiction:

Improvecircuit structureVSAvoidsensing data accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements feedback by using the measured parasitic capacitance information to dynamically adjust the charge control circuit's compensation action. The circuit continuously monitors the parasitic capacitance effects and applies real-time charge compensation, creating a feedback loop that maintains high sensing accuracy without requiring overly complex circuit architecture

Inventive Principle:

Principle #23Feedback

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 enhances the accuracy of touch sensing by compensating for charge variations caused by parasitic capacitance, leading to improved capacitance-based touch sensing performance and reduced noise in sensing data.

Implementation Method 1

parasitic capacitance Cpara occurring inside or outside a touch screen panel

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

undesirable parasitic capacitance between touch driving patterns and neighboring conductors inside or outside a touch screen panel

Methodology Applied

Scientific EffectParasitic capacitance: Parasitic Capacitance

Data Source

PatentUS10496230B2Touch circuit, touch sensing device, and touch sensing method

Publication Date: 2019.12.03 LG DISPLAY CO LTD

AI summary

The present disclosure relates to a touch circuit, a touch sensing device, and a touch sensing method. According to the present disclosure, it is possible to obtain an accurate touch sensing result (the presence or absence of a touch and/or a touch position) by compensating for the unintentional change in the quantity of the charge corresponding to a signal obtained by driving a touch screen panel, so as to obtain sensing data in which the influence of the parasitic capacitance generated inside or outside the touch screen panel is reduced or eliminated, thereby improving capacitance-based touch sensing performance.