THE company that gave us the BlackBerry - still the dominant phone in corporate circles - thinks its business customers will have room in their briefcases for at least one more device: the PlayBook.

Research In Motion Ltd showed off the tablet for the first time on Monday and is set to launch it in early 2011. With it RIM is betting on a smaller, lighter device than Apple's iPad, which kick-started the tablet market when it launched in April.

The PlayBook will have a 17.8-centimeter screen, making it half the size of the iPad, and weigh about 0.4 kilograms to the iPad's 0.7 kilograms. And unlike the iPad, it will have two cameras, front and back.

The PlayBook will be able to act as a second, larger screen for a BlackBerry phone, through a secure short-range wireless link. When the connection is lost - perhaps because the user moves the phone out of range - no sensitive data such as company e-mails are left on the tablet. Outside of wi-fi range, it will be able to use cellular service to access the web by linking to a BlackBerry and will also work as a standalone device.

RIM co-Chief Executive Jim Balsillie said its goal is to present the full web experience of a computer. That means the tablet will be less dependent on third-party applications or "apps," Balsillie said.

"Much of the market has been defined in terms of how you fit the web to mobility," Balsillie said. "What we're launching is really the first mobile product that is designed to give full web fidelity."

The iPad has prompted a wave of competitors, so RIM won't be alone going after the tablet market. Dell Inc came out with its own tablet computer in August called the Streak, Samsung Electronics Co plans to launch the Galaxy Tab next month and Cisco Systems Inc is also going after business customers with a tablet called the Cius early next year.