Abstract: A liquid crystal (LC) display monitor has a high luminosity light source to provide good visibility in brightly lit areas. To prevent overheating of the LC screen and other components of the monitor, a two-phase cooler is provided. The cooler consists of two translucent, flexible bag-like containers, each conforming to a different side of the light source. A low-boiling point coolant within the containers absorbs heat from the light source and is partially vaporized. The coolant vapor travels from the containers into a condenser which is external to the monitor cabinet. The condenser draws thermal energy out of the coolant vapor, causing it to condense and return to the containers. The containers provide shock absorption to protect the light source, and the containers or the coolant may have light-scattering properties to provide diffusion of the light.