Multi-Frequency Sensor Electrode Pen Resonance Detection
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Solution Overview
Problem
Current input devices, such as proximity sensor devices, face challenges in accurately detecting and distinguishing between different input objects, particularly pens and fingers, within a sensing region, especially when they are in a non-resonating state or resonate at frequencies not aligned with the device's operational frequencies.
Innovation Solution
The system employs a processing module that drives sensor electrodes with signals at multiple frequencies to determine the resonating state and frequency of a pen, allowing for concurrent measurement and reporting of the pen's state, enabling improved detection and differentiation of input objects by analyzing the effects of these signals on the pen's resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single frequency is used for sensing, then the device complexity is reduced, but the measurement precision for distinguishing different input objects deteriorates
Solution Approach 1:
The sensing process is segmented into multiple frequency channels, where each frequency is used to detect specific object types. The sensor electrodes are driven sequentially at different frequencies (e.g., first frequency for pens, second frequency for fingers), allowing the system to distinguish between object types by analyzing frequency-specific impedance changes without requiring complex simultaneous multi-frequency processing circuitry.
Solution Approach 2:
The sensing system changes the operating frequency parameter of the sensing signals to differentiate between input objects. By varying the frequency of the driving signals and measuring the corresponding impedance changes at each frequency, the system can identify whether an object is a pen, finger, or other input device based on their distinct frequency-dependent electrical characteristics.
2Measurement precision
If multiple frequencies are used for sensing, then the measurement precision for object differentiation is improved, but the device complexity increases
Solution Approach 1:
The sensing process is segmented into multiple frequency channels, where each frequency is used to detect specific object types. The sensor electrodes are driven sequentially at different frequencies (e.g., first frequency for pens, second frequency for fingers), allowing the system to distinguish between object types by analyzing frequency-specific impedance changes without requiring complex simultaneous multi-frequency processing circuitry.
Solution Approach 2:
The system employs periodic switching between different sensing frequencies in a time-multiplexed manner. The sensor electrodes are driven at a first frequency during one time period, then switched to a second frequency in the next time period, and so on. This periodic action allows multi-frequency sensing to be implemented with simple sequential circuitry rather than complex parallel multi-frequency generators.
3Loss of information
If resonating state detection is added, then the information quantity about input objects is increased, but the difficulty of detecting and measuring increases
Solution Approach 1:
The system detects resonance by driving the sensor electrodes with sinusoidal signals at frequencies that may match the resonant frequency of a pen (which contains an internal resonating element). When the pen is in a resonating state, it exhibits a characteristic impedance minimum at its resonant frequency. By sweeping through a range of frequencies or checking specific frequencies, the system can detect this resonance condition and determine the pen's state without requiring complex vibration sensing hardware.
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 approach enhances the usability of input devices by accurately identifying the resonating state and frequency of pens, allowing for precise interaction and communication of additional information, such as color changes or commands, without the need for active transmission, thereby improving user interaction with electronic systems.
Implementation Method 1
obtain, concurrently with the driving of the sensor electrodes with the first sensing signals, first measurement values that are based on effects of the first sensing signals, and a resonance of a pen in a sensing region
Data Source
AI summary
A processing system includes a sensor module coupled to sensor electrodes. The sensor module is configured to drive the sensor electrodes with first sensing signals and with second sensing signals at a second frequency. The processing system further includes a determination module configured to obtain, concurrently with the driving of the sensor electrodes, first measurement values that are based on effects of the first sensing signals, and a resonance of a pen in a sensing region. Concurrently with the driving of the sensor electrodes, second measurement values are obtained that are based on effects of the second sensing signals, and the resonance of the pen in the sensing region. The determination module determines a resonating state of the pen based on the first measurement values and the second measurement values, and reports the resonating state of the pen.