Electrical engineering. A device using cathode ray tubes. It receives video signals from a computer and displays information for the user. Possible adverse health effects of cathode ray tube displays were investigated in the 1980s.
Liquid crystal displays (LCDs) have displaced cathode ray tube displays in most applications. LCD displays utilize two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causes the crystals to align so that light cannot pass through them.