The iPhone 5 could have a curved display, according to reports from Taiwan.

Digitimes reckons that Apple has 200-300 special glass cutting machines waiting to be moved onto production lines in its assembly plants.

Apple apparently bought the machines because the display manufacturers think they're too expensive to invest in when few smartphones have curved screens. The Google Nexus S is one of the few models that currently has a curved screen.

The fact that the machines aren't yet online suggests that large-scale manufacturing of iPhone 5 is still some weeks away.

"Apple is currently still working with related suppliers including those involved in cover glass, glass cutting, lamination and touch sensors to improve yield rates," the Digitimes report says.

There have been a number of rumours about the screens of the iPhone 5 circulating in recent months, most recently concerning an edge-to-edge display.

It has also been hinted that Toshiba could be working on HD displays for future iPhones.