Touch Input System Discharge Circuit for Charge Accumulation

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Solution Overview

Problem

Conventional touch input systems face challenges in accurately detecting input coordinates due to accumulated electric charges, which can lead to inaccurate capacitance changes and potential device damage when switching between electrostatic capacitance and electromagnetic induction driving modes.

Innovation Solution

A touch input system that includes a discharge circuit to remove electric charges from sensor electrodes, improving detection accuracy by ensuring accurate capacitance changes during position detection and attribute identification processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If electromagnetic induction driving is performed, then attribute identification capability is improved, but electric charges accumulate in the sensor electrodes causing detection inaccuracy

Engineering Contradiction:

Improveattribute identification capabilityVSAvoidcapacitance change detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The discharge circuit is activated before switching from electromagnetic induction driving to electrostatic capacitance driving to remove accumulated electric charges from the sensor electrodes. This preliminary discharge action prevents charge accumulation from affecting subsequent capacitance measurements, ensuring accurate position detection while maintaining the ability to perform attribute identification through electromagnetic induction.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If electromagnetic induction driving is switched to electrostatic capacitance driving while charges are accumulated, then position detection capability is improved, but device damage may occur due to charge flow into the sensor

Engineering Contradiction:

Improveposition detection accuracyVSAvoiddevice safety

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The discharge circuit is activated in advance before switching driving modes to remove accumulated electric charges from the sensor electrodes. This preliminary discharge prevents dangerous charge flow into the sensor when transitioning from electromagnetic induction to electrostatic capacitance driving, ensuring both accurate position detection and device safety.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The discharge circuit acts as an intermediary component between the sensor electrodes and the driving circuits. It provides a controlled path for dissipating accumulated electric charges, mediating the transition between different driving modes and preventing direct charge flow that could damage the sensor or other components.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If a discharge circuit is added to remove electric charges, then detection accuracy and device safety are improved, but system complexity increases

Engineering Contradiction:

Improveinput detection accuracyVSAvoidsystem structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The discharge circuit is designed to serve multiple functions: removing electric charges accumulated during electromagnetic induction driving, protecting the sensor from charge-related damage, and enabling accurate capacitance measurements. By consolidating these functions into a single circuit module, the patent minimizes the increase in system complexity while achieving multiple protective and performance-enhancing goals.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 system enhances input detection accuracy by effectively discharging electric charges, preventing device damage and ensuring precise position and attribute identification, thereby improving overall system performance.

Implementation Method 1

a position detection process for detecting a position on the input surface contacted by the input tool, based on a change in electrostatic capacitance of the plurality of sensor electrodes

Methodology Applied

Scientific EffectElectrostatic capacitance: Capacitance

Implementation Method 2

a discharge circuit that executes a discharge process for discharging electric charges charged in the plurality of sensor electrodes

Methodology Applied

Scientific EffectElectric charge discharge: Electrostatic Discharge

Implementation Method 3

when an electromagnetic induction is driven, electric charges are accumulated in a capacitive sensor

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11009975B2Touch input system

Publication Date: 2021.05.18 SHARP KK

AI summary

Provided is a touch in, system for entering an input with an input tool onto an input surface for touch input. The touch input system includes a plurality of sensor electrodes, a position detection circuit that executes a position detection process for detecting a position on the input surface contacted by the input tool, based on a change in electrostatic capacitance of the plurality of sensor electrodes, an input tool identification circuit that executes an attribute identification process for identifying an attribute for the input tool, and a discharge circuit that executes a discharge process for discharging electric charges charged in the plurality of sensor electrodes.