Sony Ericsson is a joint venture (est. 2001) by the Japanese consumer electronics company Sony Corporation and the Swedish telecommunications company Ericsson to manufacture mobile phones. They sought to combine Sony's consumer electronics expertise with Ericsson's knowledge in the communications sector. There are often notable elements of Sony products incorporated into their phones, such as cyber-shot cameras, walkman, and more recently with the Xperia Play, the PSP.
They have traditionally used Symbian operating systems but have recently started using the Android system a lot more with phones such as the Xperia X10.