LCDs used in outdoor situations have many concerns to deal with in addition to any that they might normally encounter during indoor use. Initially some concerns are weather related such as moisture in the air or extreme temperatures. Another concern that is often not understood or just not known about at all is sunlight damage.
Liquid crystal displays use organic components that are susceptible to UV (<400 nm) and IR (>750 nm). These bandwidths of radiation have an observable impact on the organic components in LCDs. Extended exposure has been known to cause a color shift and a washed out look to images displayed with the LCD.
Over time the UV and IR radiation degrade the organic components causing them to fail to function properly. The amount of time it takes can vary depending on brand and model as well as specific weather conditions the display has been exposed to. For instance some atmospheric disturbances can reduce the amount of Ultraviolet that is transmitted to the display.
In any case it is important to protect your display from the elements, especially if it is going to be exposed to harsh environments not intended by the manufacturer. One way to do this would be to utilize a Hot Mirror with a UV blocker. This will significantly reduce the amount of IR radiation between 750 nm and 1200 nm, as well as the UV radiation below 400 nm. If the LCD is going to be used outdoors for extended periods then an extended hot mirror may be necessary, which extends the bandwidth protection out to 1600 nm and will help reduce some of the longer wavelength IR damage.
Another concern with liquid crystal displays are their susceptibility to overheating due to excess IR radiation. The LCD is intended to operate within a certain range of temperatures according to the manufacturer’s instructions and outdoor use can lead to higher than normal temperatures. The display being exposed to excessive heat can cause the crystal to become isotropic and fail to perform properly. A hot mirror can help alleviate these concerns as well by reducing the amount of infrared radiation that heats the display.