Input Detection System Resonance Frequency Adjustment

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Solution Overview

Problem

Existing input detection systems face false detection issues due to external noise interference, particularly when the noise frequency is close to the drive frequency of the touch panel and the resonant frequency of the input support device, and adjusting the drive frequency can cause deviations, making it difficult to prevent false detection without adjustable circuit constants in the input support device.

Innovation Solution

An input detection system is designed with a detection device featuring sensor electrodes, an LC circuit-based input support device, and a control circuit that includes a drive signal supply and an adjustment circuit to adjust the circuit constant between the sensor electrodes and the LC circuit electrodes, allowing for the detection frequency to be changed to avoid noise frequencies, thereby preventing false detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the drive frequency of the touch panel is adjusted to avoid noise frequencies, then false detection is prevented, but the drive frequency may deviate from the resonant frequency of the input support device

Engineering Contradiction:

Improvedetection accuracyVSAvoidfrequency matching precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the circuit constant (capacitance value) of the adjustment circuit to adjust the resonant frequency of the input support device. By modifying the capacitance parameter in the LC circuit, the resonant frequency can be tuned to match the drive frequency of the touch panel, thereby preventing false detection while maintaining accurate resonance-based detection.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The adjustment circuit acts as an intermediary between the touch panel and the input support device. It contains an LC circuit with adjustable capacitance that couples to the sensor electrode, allowing frequency matching without requiring internal power supply or complex circuitry in the input support device itself.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If the input support device includes no internal power supply, then the device configuration is simplified, but the circuit constant of the input support device cannot be adjusted

Engineering Contradiction:

Improvepower supply configurationVSAvoidcircuit constant adjustability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

Instead of making the input support device adjustable (which would require internal power supply and increase complexity), the patent inverts the approach by placing the adjustment circuit in the touch panel. The touch panel's control circuit adjusts the circuit constant of the adjustment circuit to match frequencies, achieving adaptability without complicating the input support device.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The adjustment circuit serves as an intermediary that provides frequency adjustment capability without requiring power supply in the input support device. It contains an LC circuit with controllable capacitance that can be adjusted by the touch panel's control circuit, enabling frequency matching while keeping the input support device simple and passive.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If the drive frequency matches the noise frequency, then the system operation is simple, but false detection occurs

Engineering Contradiction:

Improvefrequency control simplicityVSAvoiddetection accuracy

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The control circuit monitors the detection results and adjusts the circuit constant of the adjustment circuit based on feedback about false detection occurrences. When false detection is detected (indicating frequency mismatch), the control circuit modifies the capacitance value to realign the resonant frequency with the drive frequency, preventing future false detections while maintaining simple operation.

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 system effectively prevents false detection by adjusting the detection frequency to differ from noise frequencies, ensuring accurate detection of input support devices and fingers, even without adjustable components in the input support device, thereby enhancing detection accuracy and simplifying the device configuration.

Implementation Method 1

a method with which the input support device is detected using resonance of a resonance circuit provided in the input support device

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

a touch panel configured to detect change in electrostatic capacitance or change in a contact region

Methodology Applied

Scientific EffectElectrostatic capacitance: Capacitance

Data Source

PatentUS11487385B1Input detection system

Publication Date: 2022.11.01 MAGNOLIA WHITE CORP

AI summary

An input detection system includes a detection device including a plurality of sensor electrodes arrayed in a detection region, an input support device including an LC circuit, a first electrode coupled to one end side of the LC circuit, and a second electrode coupled to another end side of the LC circuit, and a control circuit including a drive signal supply circuit supplying a drive signal to the sensor electrodes and an adjustment circuit coupled to the sensor electrodes. The adjustment circuit adjusts a circuit constant that is added to a capacitance between the sensor electrode and the first electrode or the second electrode facing the sensor electrode.