An LCD screen that uses a backlight. Transmissive LCDs are widely used in portable computers and provide excellent viewing indoors. They must be used outdoors in the shade because direct sunlight overwhelms the backlight, making viewing difficult, if not impossible.
A reflective LCD uses the ambient light in the vicinity. The light passes through the LCD layer to a mirror, which reflects it back to the viewer. Reflective LCDs are the least costly, but require bright light. Viewing is difficult in dark rooms or outside at night. Reflective LCDs can also be built with frontlights, which significantly improve the viewing in dimly lit environments.
A transflective LCD uses both transmissive and reflective methods. It uses a backlight as does transmissive, but also adds a reflective mirror that lets light pass through from the back.
Transflective LCDs are a compromise that allows users to obtain better viewing under both lighting conditions. However, because the mirror is built to let through backlight as well as reflect frontlight, it cannot do both equally as well as mirrors dedicated to one purpose. As a result, transflective LCDs are typically not quite as bright indoors as transmissive units and not as bright outdoors as reflective ones.