keys, thanks to a UK firm's material that exploits a quantum physics
trick.
The technology allows, for example, scrolling down a long list or
webpage faster as more pressure is applied.
A division of Samsung that distributes mobile phone components to
several handset manufacturers has now licensed the "Quantum Tunnelling
Composite".
The approach could find use in devices from phones to games to GPS handsets.
In January, Japanese touch-screen maker Nissha also licensed the
approach from Yorkshire-based Peratech, who make the composite
material QTC.
However, as part of the licensing agreements, Peratech could not
reveal the phone, gaming, and device makers that could soon be using
the technology to bring pressure sensitivity to a raft of new devices.
Quantum mace
The composite works by using spiky conducting nanoparticles, similar
to tiny medieval maces, dispersed evenly in a polymer.
None of these spiky balls actually touch, but the closer they get to
each other, the more likely they are to undergo a quantum physics
phenomenon known as tunnelling.
Tunnelling is one of several effects in quantum mechanics that defies
explanation in terms of the "classical" physics that preceded it.
Simply put, quantum mechanics says that there is a tiny probability
that a particle shot at a wall will pass through it in an effect known
as tunnelling.
QTC-enabled handset
The pressure-sensitive key can already be found in an available handset
Similarly, the material that surrounds the spiky balls acts like a
wall to electric current. But as the balls draw closer together, when
squashed or deformed by a finger's pressure, the probability of a
charge tunnelling through increases.
The net result is that pressing harder on the material leads to a
smooth increase in the current through it.
There are a number of ways to make switches or screens
pressure-sensitive, such as using mechanical switches.
However, the QTC approach is particularly suited to making thin
devices. Pressure-sensitive QTC switches can be made 70 micrometers
thick - about the thickness of a human hair.
QTC is better than switches based on so-called "conducting polymers",
because they conduct no electricity until they are pressed, leading to
better overall efficiency.
Samsung Electro-mechanics has now incorporated the QTC into the
navigation switch familiar on smartphones - in addition to the up,
down, left, right and centre button, the up and down functions are
pressure-sensitive.
This is useful for scrolling more or less quickly through, for
example, a long list of emails.
"That same model can be used in many other ways, like in games: to
control how hard I want to jump or run for example," said Peratech's
chief executive Philip Taysom.
"Electronics are being given the ability to sense something that we
take for granted, which is how much we're touching and applying
force," he told BBC News.
