Abstract
A force sensing touchscreen, which detects touch point and touch force simultaneously by sensing a change in electric capacitance, was designed and fabricated. It was made with single-walled carbon nanotubes (SWCNTs) which have better mechanical and chemical characteristics than the indium-tin-oxide transparent electrodes used in most contemporary touchscreen devices. The SWCNTs, with a transmittance of about 85% and electric conductivity of 400 Ω per square; were coated and patterned on glass and polyethyleneterephthalate (PET) film substrates. The constructed force sensing touchscreen has a total size and thickness of 62 mm × 100 mm × 1.4 mm, and is composed of 11 driving line and 19 receiving line channels. The gap between the channels was designed to be 20 μm, taking visibility into consideration, and patterned by a photolithography and plasma etching processes. The mutual capacitance formed by the upper and lower transparent electrodes was initially about 2.8 pF and, on applying a 500 gf force with a 3 mm diameter tip, it showed a 25% capacitance variation. Furthermore, the touchscreen can detect multiple touches and forces simultaneously and is unaffected by touch material characteristics, such as conductance or non-conductance.
Original language | English |
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Pages (from-to) | 28732-28741 |
Number of pages | 10 |
Journal | Sensors (Switzerland) |
Volume | 15 |
Issue number | 11 |
DOIs | |
Publication status | Published - 2015 Nov 13 |
Bibliographical note
Publisher Copyright:© 2015 by the authors; licensee MDPI, Basel, Switzerland.
Keywords
- Multi-force
- Multi-touch
- Single-walled carbon nanotubes (SWCNTs)
- Touchscreen
ASJC Scopus subject areas
- Analytical Chemistry
- Information Systems
- Instrumentation
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering
- Biochemistry