Touch Device Signal Processing for High SNR
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Solution Overview
Problem
Conventional touch technologies face limitations in achieving high signal-to-noise ratio (SNR) for touch signals, particularly in applications requiring high accuracy and sensitivity, such as under water droplet conditions or active pen technology, due to the limitations of integral Analog-to-Digital Converters (ADCs) and time divisional scanning methods.
Innovation Solution
A touch device comprising touch sensors arranged in an array with a controller that sends and receives touch signals synchronously via touch lines, utilizing modulators and adaptive control circuits to adjust signal frequencies and perform oversampling, quantization, noise shaping, and decimation to enhance SNR, and a digital modulator that filters and digitizes signals to improve touch accuracy and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If integral ADC and time divisional scanning methods are used, then device complexity is reduced, but signal-to-noise ratio deteriorates
Solution Approach 1:
The patent segments the touch sensor array into multiple groups that are scanned simultaneously rather than sequentially. Each group is processed by dedicated circuitry, dividing the complex conversion task into parallel simpler operations. This segmentation enables frequency division multiplexing where different frequency signals are used for different sensor groups, improving signal-to-noise ratio while maintaining manageable device complexity through structured parallelism.
Solution Approach 2:
The patent introduces frequency as an additional dimension for signal differentiation. Instead of only time-division scanning, the system uses frequency-division multiplexing where different touch sensor groups respond to drive signals at different frequencies. This dimensional change allows simultaneous scanning of multiple groups without signal interference, dramatically improving signal-to-noise ratio while enabling parallel operation.
2Productivity
If simultaneous scanning of multiple touch sensor groups is implemented, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent designs universal drive signal generation circuitry that can produce multiple frequency signals using the same hardware components. The signal generation unit can dynamically switch between different frequencies to address different sensor groups, making the circuit multi-functional rather than requiring separate dedicated circuits for each frequency. This universality improves productivity through simultaneous scanning while controlling device complexity by reusing circuit components.
Solution Approach 2:
The patent employs periodic switching between different frequency signals in a time-multiplexed manner. The controller alternates between applying first frequency signals to first touch sensor groups and second frequency signals to second touch sensor groups in periodic cycles. This periodic action enables simultaneous scanning of multiple groups with manageable complexity by using rhythmic, predictable signal patterns that simplify timing and synchronization.
3Measurement precision
If frequency division multiplexing is used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the functions of multiple drive signal generation circuits into a single integrated signal generation unit. Instead of having separate circuits for each frequency, the system combines frequency synthesis, signal switching, and timing control into one unified module. This merging approach improves measurement precision through clean frequency-separated signals while reducing device complexity by eliminating redundant circuitry and interconnections.
Data Source
AI summary
A touch device, an electronic device and a driving method are provided. The touch device includes: a plurality of touch sensors arranged in an array; a plurality of touch lines connected to the plurality of touch sensors; and a controller connected to the plurality of touch lines, wherein the controller is configured to simultaneously send a plurality of first touch signals respectively to the plurality of touch sensors via the plurality of touch lines, and simultaneously receive via the plurality of touch lines a plurality of second touch signals generated by the plurality of touch sensors.