What role does a backlight play in an LCD display?

In an LCD (Liquid Crystal Display), the backlight is critical for visibility because it provides the necessary illumination for the pixels on the screen. LCD technology relies on liquid crystals that vary in alignment when an electric current is applied. However, these liquid crystals do not emit light on their own; instead, they manipulate the light produced by the backlight.

When light from the backlight shines through the liquid crystals, it is either blocked or allowed to pass through in varying amounts, which creates the images and colors seen on the display. Without the backlight, an LCD would appear dark and unreadable because the liquid crystals would not be able to produce any visible image without a source of illumination.

This is distinct from other functions described in the choices, such as powering the liquid crystals, enhancing color saturation, or processing images. The backlight's primary role is solely to provide illumination, making it essential for the display's functionality.