Different Lighting Types LCD Display

In non-emissive displays, most are liquid crystal displays(LCDs), which sandwich a layer of liquid crystal molecules between two thin layers of polarized glass, equipped with a light source, such as a backlight panel or reflector, to illuminate the pixels. LCD displays can operate with three different lighting configurations, which makes them suitable for a wide range of ambient light conditions:

Transmissive- Light from the backlight passes through the LCD unit depending on the direction in which the liquid crystal molecules move. The direction in which liquid crystal molecules move can be turned on or off by an electric field. Backlight can generate a lot of light, making the display image bright. However, conventional backlights typically consume a lot of energy because they are always “on” even when no image content is displayed(e.g., a TV is on, but a black screen is displayed).

Reflective-ambient light provides illumination. Typically, a mirror is placed behind a liquid crystal layer to receive light, which is then reflected back through an LCD. The advantages of this type of display are low energy consumption and high readability in bright sunlight even in outdoor environments. LCD displays can be reflective, such as silicon-based liquid crystal (LCoS) panels. But today, the most common reflective lighting application is e-paper displays. The image on the e-paper display is created by manipulating charged black and white particles(more recently colored particles), but the illumination source comes from reflected ambient light.

Reflective, transflective and transmissive displays’ illuminance principle