Microsoft Corp filed lawsuits for patent infringement on Monday against bookseller Barnes & Noble Inc over its Nook electronic book reader, widening the software company's legal assault on devices running on Google Inc's Android system.

Microsoft, which has already sued Motorola Mobility Holdings Inc over its Android phone handsets, said Barnes & Noble's e-readers infringe several Microsoft patents with software used to tab between screens, surf the Web and interact with e-books.

The lawsuit is just one of many in the emerging and hotly disputed mobile computing sector, with software and hardware makers scrapping over who owns the original technologies deployed in smartphones and tablet devices.

Finnish phone maker Nokia sued iPhone maker Apple Inc two years ago, and Apple subsequently sued handset maker HTC Corp. Software maker Oracle Corp has sued Google over Android software.

The growing e-book market has so far not been a target for lawsuits. Just over a year ago, Microsoft signed a patent agreement with Amazon.com over its market-leading Kindle e-reader, which runs on a mix of open source and Amazon's proprietary software. Microsoft received money from Amazon under that deal, but did not say how much.

In lawsuits filed in federal court in Seattle and with the International Trade Commission on Monday, Microsoft claimed the Nook line of e-readers infringe five Microsoft patents, concerning the way they display retrieved images, show the status of downloaded material on a small screen, edit electronic documents and render annotations.

The lawsuit also charged the makers of the devices, Foxconn International Holdings Ltd and Inventec Corp, with patent infringement.

The Android platform infringes a number of Microsoft's patents, and companies manufacturing and shipping Android devices must respect our intellectual property rights, Horacio Gutierrez, deputy general counsel of Microsoft's intellectual property and licensing, said in a statement.

We have tried for over a year to reach licensing agreements with Barnes & Noble, Foxconn and Inventec. Their refusals to take licenses leave us no choice but to bring legal action to defend our innovations.

Barnes and Noble said its policy is not to comment on litigation. Foxconn and Inventec could not immediately be reached for comment.

The case is 2:11-cv-00485 Microsoft Corporation v. Barnes & Noble, Inc. et al, in the United States District Court for the Western District of Washington (Seattle).

(Reporting by Bill Rigby; editing by Andre Grenon, Gary Hill)

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