Capacitive Rotary Knob Assembly for Water-Resistant Position Detection
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Solution Overview
Problem
The existing input devices with capacitive touchscreens and handles face challenges in reliably distinguishing capacitive coupling from external interference, particularly from liquids, leading to unreliable position detection.
Innovation Solution
The input device employs a capacitive detection system with an array of electrodes and an electronic evaluation unit that generates varying electrical measuring fields, along with a handle and coupling electrodes, to achieve robust capacitive coupling and position detection, minimizing interference from liquids by using multiple measuring fields and calibration data for accurate position information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive coupling between the handle and the capacitive detection device is used for position detection, then position detection capability is improved, but reliability deteriorates due to interference from water-containing liquids
Solution Approach 1:
The capacitive detection device is segmented into multiple independent array electrodes arranged in a grid pattern. Each electrode can independently detect capacitive influences, allowing the system to distinguish between legitimate handle coupling (which affects specific patterns of electrodes) and liquid interference (which creates different capacitive patterns across the electrode array). This segmentation enables reliable position detection even in the presence of liquids.
2Ease of operation
If the handle covers the capacitive electrode structure for position detection, then haptic feedback is improved, but measurement precision deteriorates due to obscured electrode detection
Solution Approach 1:
A coupling electrode is introduced as an intermediary element between the handle and the array electrodes. The coupling electrode is positioned to make contact with or come close to specific array electrodes, enabling capacitive coupling for position detection while the handle itself remains positioned to provide haptic feedback. This intermediary allows both functions to coexist without mutual interference.
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 solution enhances the accuracy and reliability of position detection, effectively filtering out background noise and external interference, ensuring robust operation even in the presence of water, and supports additional functionalities like tilting and rotation.
Implementation Method 1
a capacitive detection device (2), wherein the detection device has a detection surface (100) formed by an array of array electrodes (X0 to X8; Y0 to Y8) associated with the detection surface
Implementation Method 2
an electronic evaluation unit (14), electrically connected to the array electrodes, in order to generate, by means of the array of array electrodes, an associated array of electrical measurement fields, for the spatially resolved detection of a capacitive influence on the detection surface
Implementation Method 3
capacitive coupling between the handle, in particular the coupling electrode provided therein, and the capacitive touchscreen or capacitive touchpad is required
Data Source
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AI summary
The invention relates to a rotary knob having (inter alia, adjustable) a coupling electrode and capacitive coupling devices for placing on a touch screen. Depending on the position of the rotary knob or of the coupling electrode, contact of a corresponding partial region of the touchscreen is detected. The aim of the invention is to detect and ignore disturbing influences such as drops of water.