Samsung has filed an application for what could potentially be a key patent on touch screens. In US patent number 20140055407, published on February 27, 2014, Samsung state that “the present invention relate(s) generally to touch display devices”, meaning all touch screens that are able to differentiate between weak and strong touch. The key sensing components in the device are made from graphene or carbon nanotubes.
Graphene touch screen operation. The resistance of the sensor changes as a function of applied force.
More particularly, the patent application claims a force sensor-based screen, where the force sensing is provided by a piezoresistive element. The application claims: “While a conventional touch screen panel senses the location of a touch input by a user, it may not sense a force applied by the user.” The idea of the device is that the touch element is pasted on top of the display. The touch element consists of a touch-sensitive substrate (flexible insulation), electrodes that register the touch, and a touch processor. The touch electrodes are distributed in a matrix that is used to determine the position of the touch. It is the electrodes themselves which are piezoresistive and are to be constructed from carbon nanotubes or graphene.
Graphene touch screen, consisting of protective plastic, graphene sensors, sensing processor, and the display itself.
Several potential varieties of the device are outlined in the application, but in general it seems that Samsung is intending to put their flag on graphene-based touch screens, at least in the general case that the sensing component sits on top of the display component, with an insulating (plastic or glass) protective cover.
In a patent approved almost exactly a year to date, Samsung claimed the use of graphene as the conductive layer in the more traditional variant of the touch screen.
