A US patent granted to Apple on Thursday seems to support reports that the company is working on an ultramobile PC to compete with Microsoft and its hardware partners in that market. The patent adds weight to rumours that Apple is set to launch such a product at Macworld San Francisco on Tuesday 15 January, 2008.

The patent filed with the US Patent and Trademark Office defines "a docking area configured to receive a portable computer," according to the filing. Apple and the legal firm of Van Pelt, Yi and James LLP filed the patent application on 3 July, 2006.

According to the patent, the docking station will serve as a monitor for a portable computer and also enable connections between data lines and devices and the portable device when it is docked in the station. It also will enable the portable device to communicate with the docking station using Bluetooth and IEEE 80.2.11 wireless connections.

Images, available on Apple Insider, show an iMac style device with a separate dockable device, suggesting that the two devices will work in tandem.

Rumors have been swirling that Apple is working with Intel to use a new generation of ultramobile processors as the basis for a new line of devices, but so far the companies have not confirmed that. Microsoft released a Windows-based ultramobile PC platform code-named Origami in 2006, and some of its hardware partners, including Sony and Samsung, have released devices based on the OS. So far, the devices have not garnered widespread interest from customers.

Apple's interest in an ultramobile PC would make sense based on the popularity of its iPhone device, which was released last June and was widely hailed as the best gadget of 2007. The iPhone has a user friendly interface with the ability to check email and surf the web, so it would not be a stretch for Apple to move into the market for devices that fall somewhere between the iPhone and notebook computers.

Apple did not reply to requests for comment about the patent on Thursday.