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Analysis of Multi-Level Simultaneous Driving Technique for Capacitive Touch Sensors
Jong Kang Park1, Chang-Ju Lee2,3, Jong Tae Kim4
1College of Information and Communication Engineering, Sungkyunkwan University, Seobu-ro 2066, 16419 Suwon, Korea. jkpark1@skku.edu.
Sensors (Basel, Switzerland)
|September 5, 2017
Summary
This study introduces a novel multi-level Hadamard matrix driving technique for capacitive touch sensors, enhancing signal-to-noise ratio (SNR) and enabling thinner displays. The method offers improved design flexibility and reduced voltage requirements.
Area of Science:
- Electrical Engineering
- Materials Science
- Human-Computer Interaction
Background:
- Capacitive touch sensors are crucial for modern electronics, but their performance is limited by signal-to-noise ratio (SNR) and driving levels.
- Existing simultaneous driving techniques using Hadamard matrices improve SNR but have limitations in design flexibility and power efficiency.
- Environmental noise significantly impacts the reliability and applicability of touch sensors in various integrated modules and thin displays.
Purpose of the Study:
- To develop a new multi-level Hadamard matrix driving technique for capacitive touch sensors.
- To enhance the signal-to-noise ratio (SNR) and responsivity of touch sensors.
- To enable the use of capacitive sensors in thinner displays and integrated modules by improving driving efficiency and design choices.
Main Methods:
- Development of a multi-level Hadamard matrix driving technique for sensing concurrent capacitive elements across multiple rows.
- Application of the Kronecker product to reduce transmit (TX) voltage for higher orders of simultaneous driving.
- Implementation of a system model for multiplexing capacitive signals and verification through multi-level drivers and receivers.
Main Results:
- The proposed multi-level Hadamard matrix technique offers more effective design choices compared to existing bipolar driving methods.
- Reduced TX voltage requirements were achieved for higher orders of simultaneous driving using the Kronecker product.
- Theoretical expectations and simulation results were verified by implementing multi-level drivers and receivers, confirming enhanced SNR.
Conclusions:
- The novel multi-level Hadamard matrix driving technique significantly improves the SNR and design flexibility of capacitive touch sensors.
- This advancement facilitates the integration of capacitive sensors into thinner displays and complex modules.
- The technique presents a more efficient and versatile approach to capacitive sensing compared to conventional methods.
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