The Japanese consumer giant, fresh from revealing a 172 billion yen ($1.5 billion) operating loss in the mobile communication segment for the latest quarter, said painful changes lay ahead.
"We must carry out structural reform before we can launch a new business," said Hiroki Totoki, new head of Sony Mobile Communications Inc and a Sony group executive.
"Devices with communication functions have the potential to develop further," he told market analysts and reporters in Tokyo.
"We will implement reforms first to build a company structure that allows us to manage certain risks before venturing into the new business and getting a result," he said, adding it would take "years to deeply synchronise technological and product development".
The once-mighty Sony last month announced a 109.1 billion yen six-month loss, the latest in a series of parlous results totalling billions of dollars.
Even the sharply weaker yen, which has plunged to around 118 to the dollar against about 80 two years ago, cannot smooth over the gaping holes.
In any case, analysts warn, the effect of the currency shift is fading and the industry's household names have more work to do on reinventing themselves.
Sony has said it will cut global staff numbers in the smartphone unit by 15 per cent -- about 1,000 jobs -- and not pay dividends for the first time since its shares started trading in Tokyo in 1958.
The business has been hit by weaker-than-expected results in emerging markets and a full-blooded challenge from global rivals including Samsung and Apple.