The display on the Evo 3D is a qHD (960x540) S-LCD capacitive touchscreen, with a diagonal screen size of 4.3 inches. This represents a pixel density of approximately 250ppi, a significant improvement over the Evo 4G. qHD, also known as quarter-HD, refers to the pixel dimensions that is 1/4 the area of a 1080p high-definition display. This is the equivalent of halving the individual dimensions of 1080p: 1920x1080 and preserves the HD aspect ratio of 16:9. The Evo 4G utilized a WXGA (800x480) screen with 217ppi pixel density and 15:9 aspect ratio. Because both phones have a diagonal size of 4.3 inches, the difference in aspect ratio between phones makes the Evo 3D slightly longer and thinner than its predecessor.
See also 3D Technology