Rotatable Knob Electrostatic Capacitive Touch Panel Rotation Detection
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Solution Overview
Problem
Existing sensor devices face challenges in accurately detecting the rotation angle of a rotatable knob or conductor in a touch panel system, especially when the positions of the conductor are close, leading to decreased detection accuracy and increased errors due to adjacent signal cancellation.
Innovation Solution
A sensor device comprising an electrostatic capacitive touch panel, a rotatable knob with a conductor, and a sensor controller that calculates the rotation angle by analyzing delta values between baseline and raw sensor signals, using integral values of negative and positive signals to determine the movement distance and rotation angle, while incorporating correction methods for environmental shifts like temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a rotatable knob with conductor is used in an electrostatic capacitive touch panel, then rotation operation can be detected, but detection accuracy decreases when conductor positions are close due to adjacent signal cancellation
Solution Approach 1:
The patent divides the detection process into two separate sensing periods: a first sensing period for detecting the presence/absence of the conductor, and a second sensing period for detecting the rotation angle. This temporal segmentation allows the system to process different types of information separately, avoiding signal cancellation issues that would occur if both detections were performed simultaneously using the same sensor signals.
2Productivity
If conventional sensor signal analysis is used, then rotation detection is possible, but errors increase due to adjacent signal cancellation when conductor positions are close
Solution Approach 1:
The patent implements periodic sensing operations with different purposes: a first sensing period that detects conductor presence/absence, and a second sensing period that detects rotation angle. By periodically alternating between these two sensing modes, the system achieves both detection functions while maintaining high reliability, as each sensing period is optimized for its specific detection task without interference from the other.
3Device complexity
If environmental factors like temperature are not corrected, then detection is simpler, but detection accuracy decreases due to environmental shifts
Solution Approach 1:
The patent performs preliminary correction of sensor signals based on environmental factors (such as temperature) before using these corrected signals for rotation angle detection. This preliminary action ensures that environmental shifts do not affect the accuracy of the detection, while the correction process is seamlessly integrated into the overall detection algorithm, maintaining reasonable system complexity.
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 high-accuracy detection of rotation information with reduced errors, even in environments where signal levels are affected by temperature changes, ensuring precise sensing of rotation angles and coordinates.
Implementation Method 1
a sensor device including an electrostatic capacitive touch panel, a knob disposed rotatably about a rotation axis, a conductor held by the knob and opposed to the touch panel
Data Source
AI summary
According to one embodiment, a sensor device includes an electrostatic capacitive touch panel, a knob disposed rotatably about a rotation axis, a conductor held by the knob and opposed to the touch panel on a part of a circumference about the rotation axis, and a sensor controller which controls the touch panel. The sensor controller holds a reference signal corresponding to an electrostatic capacitance in a state where the conductor is not opposed to the touch panel, and detects first coordinates of the conductor based on a first sensor signal received from the touch panel in a state where the conductor is opposed to a first position of the touch panel and the reference signal in a first sensing period.