Segmented Electrode Capacitance Sensor for Accurate Object Detection

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Solution Overview

Problem

Existing electrode configurations for mutual capacitance sensors are prone to erroneous detection due to unintentional variations in electrode distance, leading to inaccurate detection of objects, such as paper, between electrodes.

Innovation Solution

The electrode device includes a receiver electrode, two transmitter electrodes, and a dielectric substrate to fix the distance and dielectric constant between the transmitter electrodes, with a capacitance detection circuit and arithmetic processing unit to accurately determine the presence and material of objects based on changes in capacitance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single transmitter electrode is used in mutual capacitance detection, then the device structure is simple, but unintentional distance variations cause erroneous detection

Engineering Contradiction:

Improveelectrode structureVSAvoiddetection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The transmitter electrode is divided into two separate electrodes (first transmitter electrode and second transmitter electrode). This segmentation allows the system to perform differential measurements by alternately activating each electrode, thereby canceling out errors caused by unintentional distance variations and improving detection accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes the operational parameters by alternately switching between two different transmitter electrodes. This parameter change enables the detection system to distinguish between actual object presence and distance variations, resolving the contradiction between simple structure and accurate measurement.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If electrode distance is not fixed, then the device structure is flexible, but numerical value fluctuations occur regardless of object presence

Engineering Contradiction:

Improvestructural flexibilityVSAvoiddetection reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

By segmenting the transmitter into two electrodes with different spatial relationships to the receiver, the system can identify and eliminate false signals caused by distance variations, maintaining reliability without requiring rigid structural constraints.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system uses feedback from differential measurements between the two transmitter electrodes to detect and compensate for distance variations. This feedback mechanism ensures reliable detection even when the overall electrode structure remains flexible.

Inventive Principle:

Principle #23Feedback

3Ease of manufacture

If traditional single electrode configuration is used, then manufacturing is simple, but capacitance changes cannot be accurately attributed to object presence

Engineering Contradiction:

Improveelectrode fabricationVSAvoidcapacitance measurement accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The transmitter electrode is segmented into two separate electrodes that can be manufactured using standard processes. This segmentation enables accurate capacitance measurement by allowing differential measurements that cancel out manufacturing variations and distance fluctuations.

Inventive Principle:

Principle #1Segmentation

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 enables high-accuracy detection of objects by accurately measuring changes in capacitance and distinguishing between intentional object insertion and unintentional distance variations, improving detection precision and material identification.

Implementation Method 1

a dielectric substrate disposed between the first transmitter electrode and the second transmitter electrode for fixing distance and dielectric constant between the first transmitter electrode and the second transmitter electrode

Methodology Applied

Scientific EffectDielectric: Dielectric

Implementation Method 2

a capacitance detection circuit for calculating a change in capacitance between the first transmitter electrode and the receiver electrode by using a current consumed in the receiver electrode when the pulse signal is applied to the first transmitter electrode

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11360234B2Electrode device, semiconductor device, and semiconductor system

Publication Date: 2022.06.14 RENESAS ELECTRONICS CORP

AI summary

The present invention provides an electrode device, semiconductor device and a semiconductor system capable of accuracy detecting an object to be detected. According to one embodiment, the electrode device 11 is used for detecting the capacitance of the mutual capacitance system, and includes a reception electrode PR1, a transmission electrode PX1 arranged to face the reception electrode PR1, a transmission electrode PX2 arranged to face the reception electrode PR1 with the transmission electrode PX1 interposed therebetween, and a dielectric board 101 provided between the transmission electrode PX1 and the transmission electrode PX2 to fix the distance and the dielectric constant between the transmission electrode PX1 and the transmission electrode PX2.