Japan's Sharp Corp said it plans to launch a paperback-sized mini mobile PC that features a quick start-up time, touch-screen display and full keyboard, targeting niche demand between smartphones and netbooks.

Smartphones, such as Apple's iPhone, pack many computer functions in regular cellphones, and netbooks are smaller and cheaper than regular notebook PCs and optimized for simple computing tasks such as Web browsing and email. Both have enjoyed robust demand despite the global downturn.

You can take cellphones anywhere with you, and they are always on. But you have to live with a small display. Notebook PCs offer a large display and full keyboard, but their battery life is short and it takes time to start them up, Sharp Executive Vice President Masafumi Matsumoto told a news conference.

We are introducing a mobile device that you can take with you wherever you go and comes with all major notebook PC functions.

The new product, dubbed NetWalker, has a high-resolution LCD screen and runs 10 hours on a single charge.

Sharp plans to launch the device in Japan in September and expects it to sell for about 45,000 yen ($480).

The company aims to sell 100,000 units by March 2010.

No specific timing was set for release overseas, Sharp said.

(Reporting by Kiyoshi Takenaka; Editing by Chris Gallagher)