Liquid crystal displays have a well- defined ISOTROPIC or operating temperature limit, above which the LC molecules will lose their orientation and will assume a random orientation. In other words, the rod-like molecules will no longer lie in well-ordered planes stacked upon each other. Isotropic conditions will cause positive image displays to become dark, whilst negative image LCD's become transparent. This is the NEMATIC-TO-ISOTROPIC TRANSITION TEMPERATURE, or NI Transition.

LCD's will recover from brief exposure to isotropic temperatures although temperatures above +100º C will damage the display's internal coatings. The low end of the Liquid Crystal operating temperature range is not nearly as well defined.At low temperatures, as the LC molecules' movement slows down, the display's response time decreases due to the fluid's increased viscosity.

At very low temperatures, the liquid crystal material assumes a solid or crystalline state referred to as the THEORETICAL CRYSTALINE-TO-NEMETIC TRANSITION TEMPERATURE. However, LC material is very resilient, so it takes prolonged exposure to temperatures below the CN limit to crystallize LC material

Low temp effects are reversible. LCD's immersed in liquid nitrogen have been known to return to normal operation after a brief warm up. LCD's configured with heaters can operate at temperatures as low as -55ºC. However, LCD heaters require a temperature compensated power source. LCD's equipped with THIN FILM HEATERS can achieve response times equivalent to displays operating at 0C while operating at low temperatures. Increasing the power to the heater will decrease the warm up time, but will require 2 to 3 volts for every square inch of the display.