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ISO 13406-2 is an "ISO standard, with the full title "Ergonomic requirements for work with visual displays based on flat panels -- Part 2: Ergonomic requirements for flat panel displays". It is best known to end consumers for defining a series of flat-panel display "classes" with different numbers of permitted defects (or ""dead pixels"). ISO 13406-2 also provides a classification of "Viewing Direction Range Classes and Reflection Classes. NOTE: Most manufacturer's of replacement LED screens are required to tell the consumer that their policy states 2-3 dead pixels may be visible on the replacement screen.
As part of an ISO standard, the classes are guidelines, and not mandatory. Where implemented, the interpretation of the standard by the panel or end product manufacturer and effects in terms of labeling of products, what class of panel is used, etc., can vary. Most flat-panel makers use this standard as the excuse for not accepting returns of defective flat-panels. Many customers argue that it's not honest in the makers' part to sell a product that most people wouldn't accept if they knew it had these defects. Also, there is little offer of Class I panels, that added to the fact that the price of these models is usually very high, make it difficult to buy a totally guaranteed product. One solution to this problem would be to sell these defected panels at a lower price than normal ones, clearly indicating the presence of such defects.
The ISO 13406-2:2001 standard has been withdrawn and revised by the "ISO 9241-302, 303, 305 and 307:2008 standards.
The standard lists four classes of devices, where a device of a specified class may contain a certain maximum number of "defective pixels. Three distinct types of defective pixels are described:
The table below shows the maximum number of allowed defects (per type) per 1 million pixels.
|Class||Type 1||Type 2||Type 3||Cluster with more than one type 1 or type 2 faults||Cluster of type 3 faults|