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Simple and Economic Paper Based Graphitic Touch-Pad for Multipurpose Applications

Monday, 30 May 2016: 10:00
Aqua 311 B (Hilton San Diego Bayfront)
M. Bhattacharjee and D. Bandyopadhyay (IIT Guwahati)
Most of the electronic gadgets need a human intervention for interaction, for example, a keyboard for a computer or a keypad for an ipad or mobile phone. The presently available technologies are expensive and extensive research effort is directed towards developing devices that are radically economic. The present innovation employs economic materials to compose a high sensitivity touchpad, which possesses the potential to replace existing non-economic keyboards or keypads. The resistive touchpad reported here is based on paper, graphite, and polymer PDMS. While the graphite coated layers act as conductive layers in the touchpad, PDMS acts as a protective and transparent coating on the proposed device. This transparent coating also applied as dielectric spacer between two graphite coated papers. In the proposed touchpad, the location of ‘touch’ is determined from the output electrical resistance of a particular place because the output resistance differentiates the particular location to be determined. The proposed touchpad is consists of two flexible resistive sheets made of paper, which eventually enables the making of a touchpad with flexible sides. Since the touchpad is composed of a pair of resistive sheets in which, at any time, at least one of the sides is free for user to ‘touch’ in such a manner that the pad brings a portion of one of the resistive surface in contact with the other resistive surface. The paper based resistive sheets contain conductive graphite coating and a copper connect. Further, each resistive sheet including the contacts is electrically isolated from adjacent sheet by an insulator. The resistive sheets composed of paper are protected by a PDMS film in the side where the graphite layer is absent. Further, the resistive layers are also patterned in such a manner that each touch zone is separated from other by a thin PDMS layer. The proposed proof-ofprinciple prototype have shown very high sensitivity towards human touch and can be integrated with state-of-art touchscreen devices in future.