Sensor Module Electrostatic Capacitance Correction

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Solution Overview

Problem

Existing sensor modules face challenges in accurately identifying the position of an input means due to influences from electrostatic capacitance formed by the input means and sensor wirings, particularly when the input means is in close proximity, leading to potential fluctuations that affect the detection accuracy.

Innovation Solution

A sensor module configuration with sensor electrodes arranged in a matrix, connected to sensor and auxiliary wirings, and a driver circuit that performs correction processes to eliminate the influences of electrostatic capacitance formed by the input means and the sensor/wiring structures, allowing for precise identification of the input position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensor wirings are connected to sensor electrodes in a matrix arrangement, then the sensor module can detect input position, but electrostatic capacitance formed by the input means and sensor wirings causes potential fluctuations that reduce detection accuracy

Engineering Contradiction:

Improveinput position detection accuracyVSAvoidelectrostatic capacitance influence

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A shield wiring is introduced as an intermediary element between the sensor electrodes and the external environment. This shield wiring acts as a mediator that intercepts and manages electrostatic field lines, preventing them from directly affecting the sensor electrodes and thus reducing the harmful electrostatic capacitance influence while preserving the detection functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrostatic capacitance effect, which initially causes harmful potential fluctuations, is converted into a beneficial measurement signal. By using the capacitive coupling between the shield wiring and sensor electrodes, the system transforms the unwanted electrostatic influence into useful information about the input means position, allowing the harmful effect to become the basis for detection.

Inventive Principle:

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

2Measurement precision

If auxiliary wirings are added to counteract electrostatic capacitance effects, then detection accuracy improves, but the device structure becomes more complex

Engineering Contradiction:

Improveinput position detection accuracyVSAvoidwiring structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The shield wiring is designed to perform multiple functions simultaneously: it serves as an electrostatic shield to reduce capacitance effects, provides a reference potential for measurement, and can be integrated with existing sensor electrode structures. This multi-functionality allows the system to improve detection accuracy without adding separate dedicated components for each function, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The shield wiring structure is merged with the existing sensor electrode matrix arrangement. Rather than adding completely separate auxiliary wiring systems, the shield wirings are integrated into the same planar structure and fabrication process as the sensor electrodes, combining multiple functional elements into a unified structure that reduces overall system complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 enables accurate and precise identification of the input position by reducing or eliminating the wiring influence, ensuring reliable operation even when the input means is in close proximity, thereby enhancing the detection accuracy and operability of the sensor module.

Implementation Method 1

a virtual capacitance element is formed between the sensor electrodes and the input means and between the wirings connected to the sensor electrodes and the input means, resulting in a fluctuation in the potential of the sensor electrodes

Methodology Applied

Scientific EffectElectrostatic capacitance: Capacitance

Implementation Method 2

perform a correction process to eliminate, in identifying the position of the input means, at least one of an influence of an electrostatic capacitance formed by the input means and a part of the plurality of sensor wirings and an influence of an electrostatic capacitance formed by the input means and a part of the auxiliary wirings

Methodology Applied

Scientific EffectElectrostatic capacitance: Capacitance

Data Source

PatentUS12141399B2Sensor module

Publication Date: 2024.11.12 JAPAN DISPLAY INC

AI summary

Provided is a sensor module including a plurality of sensor electrodes, a plurality of sensor wirings, a plurality of auxiliary electrodes, and a driver circuit. The plurality of sensor electrodes is arranged in a matrix having first to mth rows and first to nth columns. The plurality of sensor wirings is respectively connected to the plurality of sensor electrodes. The plurality of auxiliary electrodes is respectively connected to the plurality of sensor electrodes and extends from the plurality of sensor electrodes in a direction opposite to the direction in which the plurality of sensor wirings extends from the plurality of sensor electrodes. The driver circuit is connected to the plurality of sensor wirings and is configured to obtain sensor values of the plurality of sensor electrodes on the basis of potential fluctuations of the plurality of sensor electrodes.