Temperature Compensation for LCDs The optimal contrast setting for LCDs varies with ambient temperature. For most applications this variation in contrast is tolerable over the "normal" temperature range of 0°C to +50°C. Most LCD modules are available with an extended temperature range option which allows the display to operate from -20°C to +70°C. The changes in contrast are NOT usually tolerable over this wide range of temperatures, which means a way of adjusting the contrast voltage as the ambient temperature changes must be provided.

As the temperature decreases the LCD fluid requires a higher operating voltage in order to maintain a given optical contrast. See Figure 1. One way to provide for this is to give the user control of the contrast. This is a simple solution but quite often its not desirable or practical.