Imagine if personalising the wallpaper on your computer or mobile phone was as simple as holding your favourite photo against the screen, pressing a button and waiting a few seconds for the image to appear on its display. That day may soon be here.

Toshiba unveiled a prototype LCD (liquid crystal display) panel today that does just that. The display, with a built-in scanner, was on show in Tokyo at the Electronic Display Expo (Edex).

To make the display, engineers at Toshiba began with a 3.5in polysilicon TFT (thin film transistor) LCD, similar to that found in devices such as consumer camcorders, and added image sensors among the display pixels.

The display has a resolution of 320x240 pixels and the scanner has a resolution of 960x240 pixels, which means it can reproduce, in actual size, images of anything laid flat on its surface.

Demonstrations at Edex involved business cards and photographs, and it took around seven seconds for a scan to be completed.

"We call it an input display," said Motoshi Maruno, a specialist in silicon-on-glass technology at Toshiba and a developer behind the technology. "You can use it as an ordinary display, and you can use it just like a scanner," he said.

The prototype on display at the Tokyo exhibition was completed recently and work remains to be done before the technology reaches the commercial stage, said Maruno.

Although the screen of the prototype can display 260,000 colours, the scanner function can only manage monochrome images. Maruno said a colour scanner function is among the targets of future development work.