Microsoft chairman Bill Gates will unveil a concept for a next-generation mobile device later today. The 'Carry Everywhere PC' has a 6in screen, a battery that "lasts all day" and is as thin as 10 sheets of paper.

Mobile computing will be one of the main themes of Gates's opening keynote at WinHEC in Seattle, Neil Charney, product manager for the Windows Client Group, told vnunet.com.

Mobility is set to share the spotlight with Longhorn and the unveiling of 64-bit versions of Windows.

The emphasis on mobile computers is a result of the strong sales for laptop computers, according to Charney.

Gates is also slated to demonstrate a new ultra-portable notebook from an as yet unnamed manufacturer.

The tablet PC device transforms from a laptop with keyboard to a slate-like device, and has a minimised boot time. It is scheduled for availability later this year.

Microsoft will also unveil its Auxiliary Display, a small LCD screen which shows upcoming appointments, remaining battery life and the arrival of new emails. It will be situated on the outside of laptop computers by the time Longhorn is launched in 2006.

Intel first showcased the Auxiliary Display as part of a concept laptop at the Intel Developer Forum in February 2004.

Charney told vnunet.com that Microsoft plans to unveil APIs in Longhorn that developers need to send data to the display.

Microsoft traditionally uses WinHEC to present futuristic hardware devices like the Carry Everywhere PC. Last year Gates showed off the Windows Home Concept developed together with HP.

The concept was a combination tablet PC, living room PC and remote control, switching roles from computer to digital video recorder to television.