Microsoft on Monday accused Taiwan electronics colossus Foxconn and US book seller Barnes & Noble of using its patented technology in e-readers running on Google-backed Android software.
Taiwan-based Inventec Corporation was also targeted in Microsoft's legal filings with the US International Trade Commission and a federal court in Washington state where the software giant has its headquarters.
"By bringing this case, we are protecting our investments on behalf of our customers, partners and shareholders - just as other companies do," Microsoft deputy general counsel Horacio Gutierrez said in a blog post.
"Our firm view remains, however, that licensing is the best way forward for the industry."
The legal filings assert that the bookseller's Nook e-reader and Nook Color tablet violate Microsoft patents.
Patents at issue include being able to page through on-screen windows using tabs and to annotate text without altering digital documents, according to Gutierrez.
The filings raised to 25 the total number of Microsoft patents that are the subjects of infringement litigation centered on smartphones, tablets or other devices powered by Android software.
Taiwan-based HTC Corp. last year bought a license from Microsoft to cover technology in Android-powered smartphones, the attorney said.
The legal filings came after more than a year of talks with Barnes & Noble, Foxconn, and Inventec failed to culminate in a licensing deal, according to Microsoft.