top of the heater isolated with silicon dioxide the display featured black characters on a clear background the lcd was situated in a thermal chamber with the display facing the viewing window all connections to the lcd were made through an access hole in the side of the chamber the internal temperature of the chamber was lowered to 55 u00b0 c and the lcd was stabilized at this temperature for half an hour after stabilization the lcd heater circuit and segment driver signals were switched on to heat and drive the lcd when switching the heater and segment driver on the segments turned black before the timer counted one second 9 out of 12 times the other three times the segments turned partially black before one second and fully black after 1 25 seconds in order to cause the display to become fully operational in a time period of less than 1 second it was concluded that a display 71 should be constructed as shown in fig4 in that configuration an internal heater element 81 should be in direct contact with the liquid crystal substance 21 and as in the configuration of fig1 an external heater element 41 is provided in that configuration the internal heater element 81would be pulsed on and the display 71 would be considered inoperative during the time in which the internal heater 81 is.