Natthapol Watthanawisuth, Assistance Researcher, National Electronics and Computer Technology Center (NECTEC),National Science and Technology Development Agency (NSTDA)
The Printed Graphene Security Code for Capacitive Touch Screen Application Based on Capacitance Reading Technique
Natthapol Watthanawisuth (1) , Patiya Pasakon (2) , and Adisorn Tuantranont (1,*)
(1) Thailand Organic & Printed Electronics Innovation Center (TOPIC), National Electronics andComputer Technology Center (NECTEC), Pathumthani, Thailand 12120
(2) HAYDALE TECHNOLOGIES (THAILAND) COMPANY LIMITED Thailand Science Park,Pathumthani, Thailand 12120
The purpose of this research is to disclosure process of reading the capacitance of the screen printed Graphene conductive ink by capacitive touch screen. The characteristics are dots and thickness of different Graphene ink at each point for making the difference capacitance for each point. The security card is using specified Graphene conductive ink for generating virtual capacitance on material background. The printing of that point will generate layers of different conductance when there is induction on the capacitive touchscreen device, this induction makes electric charge moves which cause of electric charge transfer and virtual ground condition.
Capacitive touchscreen will detect location similar the human finger’s touching, from this characteristic of conductive ink and conductive printing background, it is possible to control amount of electric charge transfer between the point of conductive ink to background from a number of layers, the thickness of layers and size of point of conductive ink which is controlled of size of capacitance of ink on a capacitive screen as Fig.1. The second part is a capacitance reading technique using smartphone see Fig.2, which is reading or classifying the amount of electric charge of conductive ink on the screen, by using basic electronic principal which found out that the changing of electric charge responses to magnetic field in a different way. Hence this process must use the adjustment of sensitivity on capacitive touchscreen for varying magnetic field on screen for measuring the value of electric charge on Graphene printed. The sensing module on the touch screen emit a high magnetic field means the screen is easy to induct, in the same way, if set the sensitivity of the touch screen module to emit less magnetic field will make that screen is harder to induct.
 Kamyshny, A. & Magdassi, S. Conductive nanomaterials for printed electronics. Small 10, 3515–3535 (2014).
Natthapol Watthanawisuth is an Assistant Researcher in The National Electronics and Computer Technology Center In Thailand. He currently a member of the Thailand Organic & Printed Electronics Innovation Center (TOPIC). His research interests include advanced wireless sensor network, wearable wireless device, robotics, AI, intelligence system, conductive printing application and embedded systems.
Establishment of Thai Organic and Printed Electronics Innovation Center is to locate major infrastructure of the country, and to create a consortium for collaborations. The center will invest continuously in infrastructure and equipment to facilitate R&D, and start-up companies will be encouraged to establish premises in “Innovation Cluster 2” of “Thailand Science Park”.