Indicated Position Detection with Orthogonal Transmission Signals
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Solution Overview
Problem
The integration of electromagnetic induction and capacitive position detecting systems in electronic devices leads to decreased accuracy due to electromagnetic noise interference, affecting both systems' signal-to-noise ratios and position detection precision.
Innovation Solution
Implementing orthogonal waveforms for transmission signals in both systems, ensuring they do not interfere with each other's reception signals, thereby reducing noise mixing and maintaining detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If both electromagnetic induction and capacitive position detecting systems are integrated in one device, then the device can detect positions using multiple systems simultaneously, but electromagnetic noise interference occurs between the systems causing decreased detection accuracy
Solution Approach 1:
The patent segments the transmission signals into distinct temporal slots, where electromagnetic induction system transmits during odd-numbered periods and capacitive system transmits during even-numbered periods. This time-division segmentation prevents signal interference between the two systems, allowing both to operate simultaneously without compromising detection accuracy.
Solution Approach 2:
The patent implements periodic transmission cycles where the electromagnetic induction system and capacitive system alternate their transmission periods in a regular sequence. This periodic action pattern ensures that each system transmits only when the other is not active, eliminating electromagnetic noise interference while maintaining continuous multi-system operation capability.
2Productivity
If transmission signals for both systems are sent simultaneously, then the device can process both electromagnetic induction and capacitive detection, but noise mixing occurs between reception signals decreasing detection precision
Solution Approach 1:
The patent segments the transmission timeline into distinct periods for each system. The electromagnetic induction system transmits during odd periods while the capacitive system transmits during even periods. This segmentation ensures that reception signals are also received separately in corresponding periods, preventing noise mixing and maintaining high signal-to-noise ratios for both systems simultaneously.
Solution Approach 2:
The patent establishes a predetermined transmission period sequence before actual detection occurs. By pre-defining which system transmits in which period, the system prepares the timing structure in advance, ensuring that reception signals are captured at the correct times without interference. This preliminary timing arrangement guarantees clean signal separation and high detection precision.
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 effectively suppresses noise interference, preserving the accuracy of position detection in both electromagnetic induction and capacitive systems, enabling simultaneous and precise detection of indicators.
Implementation Method 1
The position detecting device transmits a magnetic field to the electronic pen by supplying a transmission signal of a predetermined frequency to the loop coils of the sensor. The resonance circuit stores magnetic energy on the basis of an electromagnetic induction action between the resonance circuit and the loop coils of the sensor.
Implementation Method 2
Both of the systems detect the indicated position of the indicator by detecting a change in a state of capacitive coupling between sensor electrodes and the indicator. A predetermined capacitance Co (fixed capacitance) is formed at overlapping parts (cross points) between the upper electrodes Ex and the lower electrodes Ey.
Data Source
AI summary
Provided are an indicated position detecting device and an indicated position detecting method that can suppress a decrease in the accuracy of detecting a position indicated by an indicator. An indicated position detecting device for detecting a position indicated by an indicator includes a first transmission circuit and a second transmission circuit. The first transmission circuit transmits a first transmission signal related to first processing of detecting the position indicated by the indicator. The second transmission circuit transmits a second transmission signal related to second processing different from the first processing. A waveform of the first transmission signal and a waveform of the second transmission signal are orthogonal to each other in the same period.