A new Apple patent posits portables that will be thinner and tougher than any seen so far.

Apple's 'computer closure' patent describes a method of gluing the computer frame and the shell components together, using conductive paste to electically bond case components.

"Although current enclosure designs work well, in many instances it would be desirable to provide enclosures that are thinner, lighter, stronger and aesthetically more pleasing than current enclosure designs," the patent filing notes.

The approach would allow Apple to use much thinner and lighter structural materials – and also means the machines wouldn't need screws, as components could be glued in place.

The report has generated further speculation as to Apple's much-mooted sub-notebook plans.

The patent was filed in December 2006.