ratio which provides deeper and more realistic images by making blacks darker and whites brighter.
These screens are already found in smartphones made by Samsung and a few other manufacturers. But until now, tablets haven't used them because larger AMOLED screens are more difficult to produce.
Samsung announced two models in Galaxy Tab S, with screens of 8.4 inches and 10.5 inches, as measured diagonally.
The tablets will start selling in the U.S. in July at $400 for the smaller model and $500 for the larger one - the same as comparable iPads. Models with 4G LTE cellular access are expected later in the year.
Samsung is the world's second-largest maker of tablets, behind Apple and its trend-setting iPads. In recent years, Samsung has been gaining market share - at Apple's expense - by offering a wide range of sizes and quality.
Earlier this year, it unveiled a ''Pro'' brand aimed at professionals. The ''Tab'' brand has been used on Samsung's budget tablets and don't come with a stylus, as Samsung's ''Note'' tablets do. With the new screens, Samsung is elevating the Tab line to become its flagship tablet.
Besides producing richer colours, AMOLED allows tablets to be thinner and use less power because screens typically don't require backlighting. But IHS analyst Sweta Dash said the performance gap between AMOLED screens and regular LCDs has narrowed, while AMOLED screens can cost 10 to 30 percent more to make.
Samsung does have the advantage of making its own screens, and the South Korean company can afford to reduce profit margins on tablets if that boosts volume and reduces costs on the screen-production business. What it learns from making tablet screens might even help it one day make affordable AMOLED television sets.
Samsung did release an AMOLED tablet in 2012, but it was expensive and didn't sell well. The new ones will be priced more competitively.
The tablets are a quarter of an inch (6.6 millimeters) thick, which is thinner than iPads. The smaller version is also lighter than the iPad Mini, while the larger one is about the same as the iPad Air.
The new tablets will sport displays of 2,560 pixels by 1,600 pixels, matching what's found in the Pro series. By comparison, Apple's iPad Air is at 2,048 pixels by 1,536 pixels. Apple markets its displays as ''Retina'' and doesn't believe more pixels will necessarily be discernible to the eye. Apple