CrunchGear:NEC today announced it has developed a completely sealed LCD screen for use as digital information boards located in train stations and other semi-exposed areas. The prototype is protected against rain, dust, dirt and other dangers. NEC says instead of relying on external air supply, it used a new cooling technology within the LCD screens to prevent the screens from heating up. Filters aren't needed anymore, which means the LCDs can be used in dirty and dusty areas.