You can't have a 4K Ultra HDTV without some kind of 4K Ultra HD content from Sony, right?
World's First 4K Content System with Sony's Ultra HDTV : Read more
World's First 4K Content System with Sony's Ultra HDTV : Read more
The average viewing distance for living room HDTVs in America is around 7 to 10 feet, depending on the screen size. So to appear "perfectly" sharp with 20/20 Vision like the iPhone 4 Retina Display, HDTVs only need a proportionally much lower PPI in order to achieve "Retina Display" status and have the HDTV appear "perfectly" sharp and at the visual acuity limit of your eyes.
Existing 40 inch 1920x1080 HDTV is a "Retina Display" when viewed from 5.2 feet or more
Existing 50 inch 1920x1080 HDTV is a "Retina Display" when viewed from 6.5 feet or more
Existing 60 inch 1920x1080 HDTV is a "Retina Display" when viewed from 7.8 feet or more
Since the typical HDTV viewing distances are larger than the minimum distances listed above, the HDTVs appear "perfectly" sharp and at the visual acuity limit of your eyes.