Electrostatic Input Device Noise Reduction via Differential Capacitance
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Solution Overview
Problem
Existing vehicle accessory touch switches with multiple conductive plates struggle to effectively reduce noise interference, limiting their reliability in noise reduction.
Innovation Solution
An electrostatic input device incorporating a first sensor electrode for input detection, a second sensor electrode for noise detection placed between the first sensor electrode and an electronic part, and a measurement circuit that calculates the difference between the capacitance of the first sensor electrode and a value obtained by multiplying the capacitance of the second sensor electrode by a constant to reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If multiple conductive plates are horizontally aligned to detect input, then input detection capability is improved, but noise reduction effectiveness deteriorates
Solution Approach 1:
The sensor electrode is divided into multiple independent detection regions (first sensor electrode, second sensor electrode) with distinct functions. The first sensor electrode detects input signals while the second sensor electrode specifically detects noise, allowing separate measurement and processing of different signal types to improve both detection capability and noise reduction effectiveness
Solution Approach 2:
A shielding electrode is introduced as an intermediary component between the sensor electrodes and external environment. This shielding electrode acts as a mediator that blocks external electromagnetic interference and noise from reaching the sensor electrodes, thereby improving noise reduction effectiveness without affecting input detection capability
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 provides a more reliable reduction of noise interference, enhancing the accuracy and precision of input detection in electrostatic input devices.
Implementation Method 1
a capacitance measurement unit that measures a change in the capacitance of the conductive plate with respect to a ground conductor
Implementation Method 2
The vehicle accessory touch switch controls the accessory unit in response to the human body's contact with the touch portion
Data Source
AI summary
An electrostatic input device includes a first sensor electrode for input detection, an electronic part, a second sensor electrode for noise detection, the second sensor electrode being placed between the first sensor electrode and the electronic part, and a measurement circuit that measures the capacitance of the first sensor electrode and the capacitance of the second sensor electrode, the measurement circuit calculating the difference between the capacitance of the first sensor electrode and a value obtained by multiplying the capacitance of the second sensor electrode by a constant.