Toshiba Mobile Display announced that it has developed a liquid crystal display (LCD) panel that features a world-class, high-definition 498 pixels-per-inch (ppi) image in a direct-view, compact 6.1-inch screen. Despite the small screen size, the display resolution format is 2,560 × 1,600 pixels, a higher resolution than even the full HD resolution format of 1,920 by 1,080 pixels.
Macrumors - Apple has long touted the crisp resolution of its "Retina" display that debuted in the iPhone 4 with a resolution of 326 ppi (pixels per inch), a display that has since made its way to the iPod touch and now the iPhone 4S. The Retina display concept is also said to be set to make its way into the iPad 3 next year, with Apple preparing to quadruple the number of pixels to offer a resolution of 2048 x 1536 on the device's 9.7-inch screen.
Here is a pixel density chart of smartphones from Anandtech.
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