The latest iPhone 5 rumour pegs a curved glass screen for the next Apple smartphone, according to 'industry sources'.

According to Digitimes' not always completely reliable sources, Apple itself has been forced to buy between 200 and 300 special glass cutting machines to create the screens because they're too expensive for the manufacturers to invest in.

It's not clear exactly how curved the screens will be - it could be a very subtle design addition with a slight curve in the style of the fifth-gen iPod Nano, rather than an overt, avant-garde contact-lens style bounce. With more and more rumours touting very minor design upgrades, we'd imagine the former.

Crystal ball

The machines, set to be used for slicing the glass, are not yet in use. They'll enter operation once proper volume production of the iPhone 5 begins – presumably that will fairly close to launch.

Quite when that will be is anyone's guess as rumours of delays abound, and Apple is still working on getting the most out of its manufacturing runs – displays are notoriously easy to break, after all, so the company is keen to increase the number of displays that make it out of the process alive before entering full scale production.

The iPhone 5 has been long-rumoured to get a larger 3.7- or 4-inch screen, and it's not the first time the curved screen mutterings have surfaced either.

Either way, it's looking more and more likely that we'll have to wait until September to find out the truth about the iPhone 5.

Pass the time with the video our pals at T3 have put together, rounding all the iPhone 5 rumours into one handy place:

From Digitimes