[url=http://www.necmitsubishi.com/support/css/monitortechguide/index09.htm said:
Nec-Mitsubishi[/url]]In the interest of setting a standard for allowable pixel faults in a display for manufacturers, an ISO specification (ISO 13406-2) was established. The specification determined four fault classes of LCD displays, with each having a certain number of pixel faults allowed. Class 1 LCD displays are considered "perfect," allowing zero pixel or sub-pixel faults. However, this standard has been viewed as virtually impossible or much too costly for LCD display manufacturers to consider for mass production. Class 2, which allows for five pixel or sub-pixel faults, has been an extremely difficult standard for manufacturers to achieve in mass production but a select few have managed to be certified. This groundbreaking achievement is a major breakthrough in the visual display industry and has set the bar for others to follow. Consumers should be aware, though, that Class 2 displays have been certified according to manufacturing standards and do not reveal pixel faults to the untrained human eye. Remember that each pixel, or dot, on a color LCD is actually made up of 3 sub-pixels--one for red, one for green and one for blue. On an 18" LCD display, the typical resolution is 1280 x 1024, so there are 1280 x 1024 x 3 sub-pixels, or 3.9 million sub-pixels--each of which measures less than 0.28mm in height and 0.09mm in width. For comparison purposes, the finest tip of a mechanical pencil designed for precision drafting work is often 0.3mm, so a sub-pixel at 0.09mm is less than one-third of this width and barely perceptible to the naked eye in most working environments.
