The Tablet PC may be the newest toy on the block, but it suffers from an old problem: a short battery life.

A Toronto company is hoping to change all that.

Electrovaya Inc. is introducing a Tablet PC called the Scribbler, which offers three to four times more computing run time than similar machines made by major players such as Toshiba, Hewlett-Packard Co. and Acer Inc.

A Tablet PC looks like a sub-notebook but features a touch-sensitive screen. It is powered by a version of Microsoft's Windows operating system that resembles Windows XP in every way but also includes the software that drives the screen.

Officers at Electrovaya were unavailable to talk about the Scribbler Wednesday. A source said they had been summoned to New York by Microsoft chairman Bill Gates to be at the launch of the Tablet PC.

What makes the Scribbler a machine that can run from 10 to 16 hours — as opposed to a standard of three to four hours — is that the device is powered by Electrovaya's superthin, lightweight rechargeable lithium ion battery. Originally introduced at this year's Comdex computer show under the name Electrofuel, the battery boasts the highest energy density of any battery in the world and offers 100 watt-hours of running time. It can be fully charged in as little as four to five hours.

Including the battery, the Scribbler weighs less than 2 kilograms and runs any application that runs on Windows XP. It can be operated as a simple laptop with a built-in keyboard and a mouse, or with a pen.

The machine runs on an ultra-low-voltage 866 MHz Pentium III processor and comes with 512 megabytes of RAM.

But the advantages are much greater portability and a screen that measures 10.4 inches, dramatically larger than personal digital assistants. It also features an always-on wireless network, which can connect to the Internet for browsing or sending and receiving e-mail.

Mr. Gates described the tablet PC as a machine that could surpass laptop sales in a few years.

No price has yet been announced for the Scribbler, but retailers estimate Electrovaya will ask about $3,500 for it, which is comparable to machines with shorter-lived batteries made by other manufacturers.