What is retina display?

If you are not an owner of the latest technology from Apple, you may have heard of “retina display” and wondered what does the term mean. In the iPhone 4 page in  Wikipedia, there is a good definition of the term: (the bold highlighting was added by me):

The display of the iPhone 4 is manufactured by LG under an exclusive contract with Apple. It features an LED backlit TFT LCD capacitive touchscreen with a pixel density of 326 pixels per inch (ppi) on a 3.5 in (8.9 cm) (diagonally measured), 960×640 display. Each pixel is 78 micrometres in width. The display has a contrast ratio of 800:1. The screen is marketed by Apple as the “Retina Display”, based on the assertion that a display of approximately 300 ppi at a distance of 12 inches (305 mm) from one’s eye, or 57 arcseconds per pixel[42] is the maximum amount of detail that the human retina can perceive.[43] With the iPhone expected to be used at a distance of about 12 inches from the eyes, a higher resolution would allegedly have no effect on the image’s apparent quality as the maximum potential of the human eye has already been met.

Interesting, the claim was disputed by

Raymond Soneira, president of DisplayMate Technologies (who) said in an interview with Wired magazine, that the claims by Jobs are something of an exaggeration: “It is reasonably close to being a perfect display, but Steve pushed it a little too far.” Soneira stated that the resolution of the human retina is higher than claimed by Apple, working out to 477 ppi at 12 inches (305 mm) from the eyes, or 36 arcseconds per pixel.[44]

But as you can see, for all intents and purposes, the iPhone 4 (and likely later Apple technology) meets this standard:

However, Phil Plait, author of Bad Astronomy, whose career includes a collaboration with NASA regarding the camera on the Hubble Space Telescope, responded to the criticism by stating that “if you have [better than 20/20] eyesight, then at one foot away the iPhone 4’s pixels are resolved. The picture will look pixellated. If you have average eyesight, the picture will look just fine.”[45][46]

In a nutshell, if a display is such that you cannot see the pixels, then it is a retina display.

I expect that retina display will come to bigger and bigger screens as the technology advances. First the iPhone, then the iPad and other tablets, to…well as big as displays can get.


4 responses to “What is retina display?

  1. Your nutshell summary is pretty much dead-on, Bernie. Your quotes seem to be among more than several recent posts about the math behind the eye’s resolving power. Apple doesn’t necessarily need to double resolution to satisfy the Retina Display requirement but I believe it does so a) in order to facilitate the UI/graphics implementation of developers and creatives alike and b) when it comes to varying ppi on different devices, aside from the smooth clarity, UI elements, in terms of real physical dimensions should stay reasonably consistent. Increased resolution without resizing of interface elements will result in difficulty clicking/touching.

    It’s one thing to get lost in the math and talk about necessary ppi but I think at the end of the day it comes down to clarity and consistent user experience (that is to say, comfortable).

  2. Such nomenclature is a tad disingenuous is it not? I was expecting to read that a contact lens display had been invented, that would project its image directly onto the retina, whilst still enabling the wearer to see. Still waiting for this!

    • smartpeopleiknow

      When the contact lens display is invented and commercially available, I will be one of the first to blog about it. 🙂

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