Retina HD Display is a marketing term first introduced by Apple with the debut of its iPhone 6 and iPhone 6 Plus smartphones. Retina HD Displays have a high-definition quality resolution and pixel density of at least 326 pixels per inch, which is sufficiently high enough for the average person to be unable to discern the individual pixels at a normal viewing distance.
iPhone 6 With Retina HD
The iPhone 6 features a 4.7″ Retina HD Display with a resolution of 1334×750, or 326 pixels per inch, which is actually the same pixel density as in the standard Retina Display of the iPhone 5S. The iPhone 6 Plus, on the other hand, sports a 5.5″ Retina HD Display with a resolution of 1920×1080, or 401 pixels per inch.
Additional Features in Retina HD Displays
Some of the unique features in Retina HD Displays include dual-domain pixels, which enable color accuracy from corner to corner for better wide-angle viewing, an improved polarizer for clearer viewing when viewing the device with sunglasses, and precisely-aligned crystals for an enhanced viewing experience with deeper blacks and sharper text.