Retina Display : Technical and Visual Aspects

Retina Display is the patented name for the LCD which has a higher pixel density so that our eye can not perceive the pixelation at normal viewing distance. Previously we wrote about the basic technical aspects of a typical TFT-LCD Display or Thin Film Transistor Liquid Crystal Display. This article will only describe the specific points about Retina Display.

Basic Theoretical Background Behind Retina Display

Retina is patented both under Canadian Trade-marks Database and United States Patent and Trademark Office. The basic difference is with ‘normal’ non-display is that; when we look at a paper print and same text on computer screen / digital display, both never looks the same. This difference is due to various reasons, like reflected and absorbed light source; practical viewable angle of view and son on but possibly the most important is the factor – Pixels Per Inch. We talked about Image Resolution and Pixel Count in Digital Photography, the same thing applies here too.

As the things like a printed text is a real 3D object, but a digital display is a 2D, there is need to define the third variable which we usually do not use for ‘normal’ non-Retina display – this is the Pixels per Degree (PPD).

As we will normally with a MacBook Pro 15″ with Retina Display from a greater distance than an iPhone, the need of density in pixels per inch decreases. It is obvious that a pixalated image looks clear when seen from a distance.

This a patented technology, basics is the same as for TFT-LCD display. The manufacturers are usually LG and Samsung; and it is not pre-determined that which manufacturer’s display which batch will receive. There is a randomization in assembling process. Right now, for MacBook Pro 15″, the PPI is 220 and 326 for iPhone5.

Practical Aspects of Retina Display

Untrained eye can not make any difference with complex high quality colored graphical works, like in case of Icons on TFT-LCD and Retina display. The difference becomes obvious when it is about a black and white text or 2D black and white logo or art. Theoretically human retina human demands around 480 pixels per inch to get rid off the pixelated appearance. In real world, minimum PPI (if we think in this way) for ink pen and paper starts from mid four digits. Angle of view practically is unrestricted. It is basically not possible to compare in this way – Text on Retina display versus a Newspaper pasted behind a clear glass. The paper and text will always give a 3D appearance, our eyes are trained and co-ordinated in that way to be normal. Obviously a Retina Display delivers a clear view. How much that is useful or helpful, that depends on the individual.