Capacitance Difference Measurement Using Pre-Stored Impedance Mapping
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Solution Overview
Problem
Existing capacitive touch-sensing panels face inefficiencies in measuring capacitance difference due to the need for repeated impedance adjustments, resulting in unsatisfactory sensing speed.
Innovation Solution
A device and method that utilize a driving signal generator, comparator, and modulating and measuring device to output driving signals and modulating voltage signals to capacitors, adjusting voltage levels based on output signals to generate a characteristic value indicating capacitance difference, either through time or slope, for efficient capacitance measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If impedance combinations are adjusted several times to make one capacitance measurement, then measurement accuracy can be improved, but measuring efficiency and capacitance-sensing speed deteriorate
Solution Approach 1:
The patent applies preliminary action by pre-establishing a correspondence relationship between impedance combinations and modulating voltage signals before actual capacitance measurement. The controller stores multiple impedance combinations and their corresponding modulating voltage signals in advance, so that during measurement, the system can directly retrieve and apply the appropriate signal without iterative adjustment, thereby achieving both high accuracy and fast speed
Solution Approach 2:
The patent changes the parameter of modulating voltage signal characteristics (amplitude, frequency, or phase) corresponding to different impedance combinations. By establishing a predefined mapping between impedance states and voltage signal parameters, the system can rapidly switch between different measurement conditions without physical reconfiguration, resolving the contradiction between precision and speed
2Reliability
If impedance combinations are adjusted several times to make one capacitance measurement, then measurement completeness can be improved, but measuring efficiency deteriorates
Solution Approach 1:
The controller pre-stores multiple impedance combinations and their corresponding modulating voltage signals in a lookup table or memory structure. This preliminary preparation ensures that all necessary measurement configurations are readily available, eliminating the need for time-consuming iterative adjustments while maintaining comprehensive measurement coverage
Solution Approach 2:
The patent replaces the mechanical/physical process of repeatedly adjusting impedance combinations with an electronic signal processing approach. The controller electronically selects and applies the appropriate modulating voltage signal based on the measured impedance, substituting physical reconfiguration with rapid electronic switching, thereby maintaining measurement completeness while dramatically reducing measurement time
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 enables rapid and flexible measurement of capacitance difference, enhancing sensing speed and accuracy by selectively adjusting voltage levels and recording characteristic values based on state changes or slope, thereby improving overall performance.
Implementation Method 1
a comparator having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal and the second input terminal are electrically connected to the first capacitor and the second capacitor, respectively, and according to a voltage difference between the first input terminal and the second input terminal, an output signal, which is selectively switched between at least a first state and a second state, is outputted from the output terminal
Implementation Method 2
a driving signal generator electrically connected to the first capacitor and the second capacitor for outputting a driving signal to each of the first capacitor and the second capacitor in a measurement period
Data Source
AI summary
A driving signal is outputted to each of the first and second capacitors in a measurement period so that voltage changes occur at the first and second capacitors. First and second modulating voltage signals are provided for the first and the second capacitors in the measurement period. An output signal in a first state or a second state according to a voltage difference between the first and second capacitors is generated. One of the voltage values of the first and second modulating voltage is automatically adjusted according to the output signal. A characteristic value for indicating a capacitance difference between the first capacitor and the second capacitor, which correlates to a length of time from a start point of the measurement period to a specified point that a condition change of the output signal occurs or a slope of the first or second modulating voltage signal, is generated.