Just as news of the Microsoft Windows Mango 7.5 phone release is circulating, details of the company's latest patent application have surfaced.

A type of sliding keyboard smartphone is apparently in the works. The big difference between the proposed model and previous sliding phones would be interchangeable keyboards – users would be able to trade out the standard "qwerty" typing pad for a game controller, an extended display or a secondary battery.

The idea of including mobile accessories in the phone itself – and being able to change the function of the device by changing the slider – may prove to be a revolution for the smartphone gaming industry, as either touchscreen controls or an external attachment are currently necessary. Gaming-oriented phones do exist, although valuable space is taken up by the permanent controls.

Microsoft's new push into the mobile market may take a chunk out of Android device sales. Although phones running Google's operating system are popular and part of the growing mobile industry, Apple's dominance of the market, in addition to the anticipated popularity of the iPhone 5, may combine with new operating systems to lower Android's share of the market.