UK-based touch-sensor manufacturer Quantum Research is threatening to take Apple to court over technology used within its iPhone, a report claims.

The UK company is already prosecuting another lawsuit against Apple over technologies it claims are used within the iPod Click Wheel. Quantum claims electronic components — specifically the capacitive sensing technology — used in the Click Wheel breach its patents.

The company first launched that litigation against Cupertino in December 2005. Apple denied those charges and has filed counterclaims against them.

On the iPhone, Duncan Bryan, licensing director at Quantum Research said: "The description of the iPhone suggests it uses a rear-surface touch screen, and has proximity sensing which can tell if it is held to the ear. That's a Quantum Research capability."

If Apple has used charge transfer technology, QR’s patented technology, to give the iPhone that capability, then Apple could be infringing the firm’s patent, reports Electronics Weekly.