According to Apple, a display deserves the Retina moniker if its pixel density is so high that your eye is unable to discern the individual pixels. In the case of a smartphone, Retina means at least 300 pixels per inch. The Retina display on the iPhone 4/4S/5 has 326 pixels per inch.
Now, imagine a five-inch phone that packs 440 pixels per square inch, featuring the native full HD resolution of 1,920-by-1,080 pixels. That's exactly what the ailing handset maker HTC set out to create with a new upcoming phone dubbed the J Butterfly...