Samsung Electronics said Friday its fourth-quarter earnings surged 17 percent from a year earlier on the back of stronger sales in smartphones and flat screens.

The technology giant’s net income reached 4 trillion won ($3.5 billion) in the October-December period, registering the largest gain since the third quarter of 2010. Revenue went up 13 percent to an all-time high of 47.3 trillion won and operating profit climbed 75.8 percent to 5.3 trillion won in the same period.

The figures were largely in line with the company’s earnings guidance put out last month.

Analysts said solid sales of its Galaxy smartphones in the global market helped prop up its overall earnings last year despite the intensifying competition with other global players including U.S.-based Apple.

Samsung said smartphone sales rose more than 30 percent in the fourth quarter from the previous quarter, without revealing specific sales figures. Given that Samsung sold 28.1 million smartphones in the third quarter according to market research firm Strategy Analytics, Samsung is estimated to have shipped around 36 million units in the final quarter of last year.

For all of 2011, Samsung’s net profit slumped 15 percent from the previous year and operating profit edged down 6.05 percent to 16.2 trillion won. But its revenue jumped by more than 10 trillion won on-year to 165 trillion won.

On top of improved smartphone sales, Samsung’s yearly earnings got a boost thanks to the one-off proceeds it secured through the sale of its money-losing hard drive disk operation.

Last year, Samsung invested a total of 23 trillion won in facility investment, including 13 trillion won for semiconductor business and 6.4 trillion won for display panels. This year, the company earmarked 25 trillion won for new investment, signaling that it will hold on to its aggressive strategy to stay ahead in the global technology market.

Shares of Samsung ended up 1.08 percent to 1,125,000 won on Friday.

By Yang Sung-jin (insight@heraldcorp.com)