Sony ($SNE) may be expanding its focus on medical devices as part of its rebound plans, but the company will have to go through some serious pain to get there. Reuters reports that the Japanese consumer electronics giant has released details regarding expected layoffs. Sony will slash its headquarters staff by one-fifth, and close down a factory in Japan that makes cameras and mobile phones. The resulting 3,800 job cuts are part of a larger effort to eliminate 10,000 positions at Sony by March 2013. Sony is trying to reduce substantial debt and recover from four years of losses. Story