Sony Corp has launched its first tablet computers in an ambitious attempt to grab the second spot in the market created and dominated by Apple's iPad.

The gadgets will use an operating system based on Google's  Android 3.0, said Kunimasa Suzuki, deputy president of the consumer products and services group, as he unveiled one of the devices  from his jacket pocket during a media launch on Tuesday.

The tablets called S1 and S2, are WiFi and 3G/4G compatible. One of the models will have two screens, Suzuki added.

S1 has a 9.4-inch display while S2 has two 5.5-inch displays that can be folded. The tablets will allow use of PlayStation games.

Sales of tablet devices are expected to quadruple to about 294 million units between 2011 and 2015, with almost half that Android-based, research firm Gartner has forecast.

Suzuki raised eyebrows in January when he told reporters at the Consumer Electronics Show in Las Vegas that Sony was aiming for the No.2 spot in the tablet market within a year even though it had yet to put a product on the market.

The company has emphasised the need to differentiate its tablet from rivals, even if that takes time.

'Although it's a late comer in the market, it has potential as what you need is just one big uniqueness that can sell to customers be it design or whatever,' said Lee Sun-tae, an analyst at Meritz Securities in Seoul.

'By the same token it can be just one of another Android phones flooding the market amid intensifying competition.”

In a bid to tap that burgeoning demand, competitors including Samsung Electronics -- whose Galaxy Tab is Apple's strongest competitor in the tablet market -- and Motorola , LG Electronics and HTC  are flooding the market with tablets running Android.

Shares in Sony, which unveils its quarterly results on May 26, fell 2.1 per cent on Tuesday. – Reuters