Pressure sensitive technology set to bring 3D capability to touchscreens
By Darren Quick
January 31, 2010
Touchscreens found in most mobile devices today use capacitance or resistance technology - fine for detecting input from a finger, but not so great when it comes to detecting how much pressure that finger is applying. However, this limitation could be about to change with news that Japanese touch screen manufacturer, Nissha, has licensed new technology that allows a touchscreen to detect pressure, even from a finger. This adds a third dimension to touchscreen interaction and opens up a raft of potential applications.
The licensing agreement concerns Peratech’s Quantum Tunnelling Composites (QTC) technology, which is used to create ultra-thin, low power force sensitive switches of any shape or size. Adding force sensitivity to touchscreens offers the prospect of adding the third dimension to touchscreen interfaces and could give users the ability to search deeper into a file structure simply by pressing harder, or control an avatar’s movement through a game more naturally. It would also be particularly useful for handwriting recognition in Asian markets due to the variation in line thickness in Asian scripts.
QTC technology's conductive filler particles feature spikes. These spikes produce a localized increase in the electric field at the tips which effectively reduce the barrier’s width and allows conduction to occur.
As QTC is compressed, the conductive particles are brought closer together and barrier widths reduced further. This leads to an exponential decrease in electrical resistance and this ability to vary the width of the barrier through compression, tension or torsion is what gives QTC its pressure sensitivity.
Its developers say that because QTC technology has no moving parts and requires no air gap between contacts it is extremely reliable and suitable for integration into the thinnest electronic devices. It is also low power and interfaces can be designed with no start resistance so that without pressure, the switch draws no power and passes no current.