A federal court ruled on Friday 29 July 2011 that Microsoft must pay French based telecommunications giant Alcatel-Lucent $70m in a patent infringement claim. The well nicknamed "Day patent" covers the method of entering a date into a data field without using a keyboard. The patented method covers for example the date picker function which is used in Microsoft Outlook.

In an earlier trial it was found that Microsoft's Outlook, Windows Mobile and Microsoft Money had been infringing the "Day patent" and as a result Microsoft was ordered to pay a total of $358m in damages. The total amount in damages soon thereafter exceeded $500m due to interest. An appeals court subsequently overturned the initial damages award on a lack of evidential support in the damages calculation. While upholding the initial infringement ruling the case was sent back to trial on damages only.

Originally the patent application was filed in the name of a few engineers at AT&T back in 1986. Lucent Technologies, an AT&T spin-off company formed in 1996, was subsequently acquired by Alcatel. The series of lawsuits originated in 2002 when Lucent sued computer makers Gateway and Dell for infringement of the patent. Microsoft only later joined in as defendant.

At this stage there is no indication of whether Microsoft intends appealing against the latest damages award.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.