A recent patent lawsuit filed by Touchpac Holdings against TouchBase Technologies Inc. has highlighted the US Patent US8497850 which is owned by Printechnologics GmbH (T+Ink). Details of the lawsuit were reported by Printed Electronics World in their article on 18 Feb 2014.
The patent was granted on 30 July 2013 and describes the technology that T+Ink have developed and called Touchcode. This is a highly secure printed conductive ink signature embedded in packaging, labels and other objects that a smartphone or other sensing device can detect through capacitive touch. The patent provides some detail of the system which is defined in independent claim 22:
A system comprising: a. an information carrier comprising a dielectric and/or conductive pattern which encodes information, and wherein the information carrier (1) comprises a substrate (2) with a first dielectric coefficient ∈1 and a second material with a second dielectric coefficient ∈2, the second coefficient ∈2 being different from the first coefficient ∈1, or wherein the information carrier (1) comprises a substrate (2) with a first conductivity σ1 and a second material with a second conductivity σ2, the second conductivity σ2 being different from the first conductivity σ1, b. a detection device having a capacitive touch screen; the detection device decodes the information upon interaction between the information carrier and the touch screen, wherein the interaction is based on a difference in the dielectric coefficient and/or the conductivity of the pattern, wherein the interaction is induced by relative motion between the information carrier and the touch screen.
A more visual explanation can be found on the T+Ink Touchcode website. As explained on the website, Touchcode is an invisible electronic code printed on paper, cardboard, film or labels. Just put the product on the display of your smartphone/tablet/multitouch device to read the data. In this way you can add interactivity to just about any product. The system is similar to QR codes, barcodes or other tags but does not require activating a camera app on the phone or tablet to work.