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LCD Monitors -
PC
Peripherals provide an industry standard 6pixel warranty policy with regard to
the supply of LCD monitors.
General Guidelines
Guidelines for pixel defects
found in display products (effective since 02-04-2006)
At a resolution of 1024x768
pixels, where each consists of three sub-pixels (red, green, blue),
approximately 2.4 million transistors are in use altogether. Owing to this very
high number of transistors and the extreme complex manufacturing process
associated with that, in rare cases defect pixels or sub-pixels might occur. To
regulate the acceptability of defects and to protect the end user, ISO1 have
created a standard for manufacturers to follow. All PC Peripherals supplied LCD
displays for monitors and notebooks conform to LCD Class II of ISO 13406-2
standard.
In
order for the LCD to operate reliably, the liquid-crystal fluid must be
protected from the DC voltages (typically negative) that cause breakdown. If too
much DC current inadvertently flows through the LCD fluid, the fluid will become
damaged. It will then electrochemically decompose and break down over time as
the fluid changes state. This change in state becomes noticeable as the color of
the liquid-crystal pixel changes. Given further damage, gas bubbles will form
inside the liquid-crystal cell. These gas bubbles will result in permanent
damage and a noticeable degradation of display quality. Pixel damage cannot be
repaired.
All
LCDs have power-up sequencing requirements of some type. The key to power-up
sequencing requirements is to make sure that the LCD fluid is protected from DC
voltages without the AC wave being set up. It also must be kept within the
requirements that were provided by the LCD vendor. |
