Rotatable Knob Interface Capacitive Shift Detection
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Solution Overview
Problem
Existing input devices with proximity sensors face challenges in effectively integrating a rotatable knob interface, as they struggle to accurately detect the rotational position and state of the knob due to interference from environmental signals and parasitic capacitance, which affects the reliability and precision of user input detection.
Innovation Solution
A sensing system comprising a display panel with sensor electrodes and a processing system that operates subsets of electrodes with reference and sensing signals to detect the position and shift of a conductive region, allowing for precise capacitive coupling analysis to determine the rotational state of a rotatable knob interface, while minimizing interference from neighboring sensor electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If proximity sensor devices are used to detect rotational position, then user input detection capability is provided, but environmental signals and parasitic capacitance interfere with detection accuracy
Solution Approach 1:
The sensor electrodes are divided into two distinct subsets: a first subset driven with a reference signal and a second subset driven with a sensing signal. This segmentation allows the system to separate reference measurements from actual sensing measurements, enabling subtraction of environmental interference and parasitic capacitance effects from the rotational position detection, thereby improving measurement precision while maintaining user input detection capability.
2Area of stationary object
If all sensor electrodes are operated for input sensing, then comprehensive sensing coverage is achieved, but environmental interference and parasitic capacitance affect measurement accuracy
Solution Approach 1:
The sensor electrodes are segmented into two subsets with distinct functions: the first subset operates as a reference with a constant signal to capture environmental interference and parasitic capacitance, while the second subset performs actual input sensing. This allows comprehensive sensing coverage to be maintained while improving precision through differential measurement.
Solution Approach 2:
The first subset of sensor electrodes acts as an intermediary reference that captures environmental interference and parasitic capacitance effects. By comparing the second subset's sensing signals against this reference, the system can eliminate the intermediary interference factors and achieve more precise input detection.
3Measurement precision
If sensor electrodes are driven with sensing signals for shift detection, then rotational position can be determined, but environmental signals interfere with the resulting signals
Solution Approach 1:
The first subset of sensor electrodes serves as an intermediary reference that captures environmental signals and parasitic capacitance. The processing system uses this reference to subtract and eliminate environmental interference from the sensing signals obtained from the second subset, thereby enabling accurate shift detection without harmful environmental factors affecting the measurement.
Solution Approach 2:
The system continuously monitors the first subset of sensor electrodes for environmental interference and parasitic capacitance effects, then feeds this information back to compensate for and eliminate these effects from the second subset's sensing measurements. This feedback mechanism maintains high measurement precision despite environmental signal 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
The solution enables accurate detection of the rotational position and state of the rotatable knob interface, enhancing user input reliability and precision by isolating the sensor electrodes and using specific signal driving methods to mitigate environmental interference.
Implementation Method 1
the resulting signals received from the first subset of sensor electrodes during the second period are affected based on the position of the conductive region relative to the display panel
Data Source
AI summary
A method of detecting shift of a rotatable interface is disclosed. The rotatable interface has a fixed base with a conductive region on a bottom surface, the fixed base attached to a display screen of an input device. The method includes providing, during a first time period, a reference signal to first and second sets of electrodes of the input device that are each capacitively coupled to the conductive region. The method further includes, during a second time period, providing the reference signal to the first set of electrodes, providing a sensing signal to the second set of electrodes, and receiving, during the second time period, a resulting signal on the second set of electrodes. The method still further includes determining a translation of the rotatable interface relative to the display screen based, at least in part, on the resulting signal values received during the second time period.