Microsoft has signed patent-protection deals with a number of PC and tablet makers in the past couple of years. Now it's also forging similar deals with more companies embeddeding the Android operating system inside consumer devices.

Microsoft announced on February 21 that it has signed a patent-licensing agreement with Nikon. The agreement "provides broad coverage under Microsoft’s patent portfolio for certain Nikon cameras running the Android platform," according to Microsoft's press release.

Microsoft and Nikon have agreed not to disclose specifics, but Microsoft is acknowledging that it will receive undisclosed royalties from Nikon as part of the deal. Like Microsoft's other Android, Linux and Chrome OS patent deals, exactly which Microsoft-patented technologies the vendors are licensing is unknown.

At least some, if not all, of Nikon's Coolpix cameras are using Android inside.

This isn't the first embedded vendor with which Microsoft has signed an Android patent deal. In December 2012, Microsoft announced an Android patent deal with Hoeft & Wessel AG , a German manufacturer of devices and terminals for the public transportation, logistics and retail industries that use Android as their embedded operating system. It also signed a patent-licensing agreement with TomTom, a GPS maker, as part of a patent-infringement settlement.

Previously, Microsoft signed patent-licensing deals with a number of key OEMs and ODMs (original design manufacturers) using Linux, Android and Chrome OS , including Amazon, Barnes & Noble, Buffalo, Compal, General Dynamics, HTC, LG Electronics, Pegatron, Samsung, and Velocity Micro, among others.

News of Microsoft's latest Android patent deal comes the same day that Microsoft and Oracle met with lawmakers in Washington to defend software patents. The pair are proposing losers in software patent suits pay the winners' legal costs as a way to try to discourage dubious patent suits.

Microsoft also is promising the company will publish on the web as of April 1 information that enables anyone to determine which patents Microsoft owns.