Touch Electrode Frequency Segmentation for Noise-Resistant Position Sensing
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Solution Overview
Problem
Existing touch apparatuses face challenges in accurately detecting touch inputs, particularly from different objects, and are prone to noise interference, which affects reception sensitivity and precise position calculation.
Innovation Solution
The touch apparatus employs a driver to apply distinct driving signals to alternating sets of touch electrodes at different frequencies, with a receiver using differential amplifiers to enhance signal detection and a controller to determine touch positions based on signal strength thresholds, distinguishing between inputs from fingers/palms and stylus pens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional amplifiers are used to receive detection signals from touch electrodes, then the touch sensor can detect touch inputs, but noise interference reduces reception sensitivity and measurement precision
Solution Approach 1:
The touch electrode array is divided into multiple groups, with different driving signals applied to different groups at different frequencies. This segmentation allows the system to distinguish between signals from different touch objects (finger vs. stylus) by frequency, thereby improving reception sensitivity while filtering out noise and unwanted signals.
Solution Approach 2:
The patent changes the frequency parameter of driving signals applied to different touch electrode groups. By using distinct frequencies for different electrode groups and detecting at specific frequencies, the system can selectively receive signals from intended touch objects while rejecting noise and signals from other objects, thus improving reception sensitivity.
2Measurement precision
If amplifiers are provided for each touch electrode to enhance signal detection, then detection capability improves, but device complexity increases
Solution Approach 1:
The patent implements a universal amplifier that can receive detection signals from multiple touch electrode groups. Instead of having dedicated amplifiers for each electrode, a single amplifier is configured to detect signals from different electrode groups at different frequencies, thereby reducing device complexity while maintaining measurement precision through frequency-based signal differentiation.
Solution Approach 2:
The universal amplifier utilizes frequency as a distinguishing parameter to differentiate between signals from different touch electrode groups. By tuning the amplifier to specific frequencies corresponding to different electrode groups, the system achieves precise touch detection without requiring separate amplifiers for each electrode, thus reducing overall device complexity.
3Adaptability or versatility
If the touch apparatus uses single-frequency driving signals, then the system is simpler to implement, but it cannot distinguish between different touch objects (finger and stylus)
Solution Approach 1:
The touch electrode array is segmented into multiple groups, each driven at a distinct frequency. This segmentation enables the system to differentiate between touch objects based on which electrode groups are activated and at what frequencies, thereby achieving touch object discrimination capability while managing signal processing complexity through organized frequency allocation.
Solution Approach 2:
The patent changes the frequency parameter of driving signals applied to different electrode groups. By monitoring which frequencies are activated during touch detection, the system can identify the type of touch object (finger or stylus) and its position, enhancing adaptability and versatility without excessive complexity through systematic frequency management.
4Measurement precision
If the touch apparatus applies driving signals to all touch electrodes simultaneously, then detection coverage is maximized, but noise from all electrodes interferes with signal reception
Solution Approach 1:
The touch electrode array is divided into multiple groups that are driven at different frequencies. During detection, the system can selectively receive signals at specific frequencies corresponding to particular electrode groups, thereby achieving comprehensive detection coverage while filtering out noise from other electrode groups through frequency-based signal separation.
Solution Approach 2:
The patent utilizes frequency as a parameter to differentiate between signals from different electrode groups. By applying driving signals at distinct frequencies to different groups and detecting at corresponding frequencies, the system achieves full detection coverage while minimizing noise interference through frequency-selective signal reception.
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 improves reception sensitivity and enables accurate calculation of touch positions, effectively distinguishing between different touch objects and filtering noise, thereby enhancing the overall touch detection performance.
Implementation Method 1
The driver may sequentially apply a pulse signal of a first frequency to the first touch electrodes as the first driving signal during the first period. The driver may apply a pulse signal of a second frequency that is higher than or equal to a first frequency to both first touch electrodes and second touch electrodes as a second driving signal during the second period.
Implementation Method 2
The receiver may include an amplifier connected to each of the second touch electrodes during the first period to amplify and output a detection signal from a corresponding second touch electrode.
Implementation Method 3
A plurality of differential amplifiers may receive only a third detection signal generated by the second touch object in response to the second driving signal during the second period. The controller may determine a touch position based on the signal outputted from the receiver.
Data Source
AI summary
An exemplary embodiment of the present invention provides a touch apparatus including: a touch panel including a plurality of first touch electrodes arranged in a first direction and a plurality of second touch electrodes arranged in a second direction crossing the first direction; a driver configured to apply a first driving signal to the first touch electrodes during a first period and a second driving signal to the second touch electrodes during a second period subsequent to the first period; a receiver configured to receive a detection signal from the second touch electrodes during the first period, and a detection signal from the first touch electrodes and the second touch electrodes during a third period subsequent to the second period; and a controller configured to determine a touch position based on the signal outputted from the receiver.