LCD displays are normally black when off and only transmit around 4-8% of light produced by their backlight through them when running. This light is passed through a partially / fully opening and closing a red, green and blue filter which is referred to as a Pixel, which in turn forms the desired pixel colour.

Transparent screens rather than having black around the pixels are transparent, and the red, green and blue dots are still driven in a similar way to a normal LCD display, however to see an image on the display a light source is required behind the LCD its self. This lends them to being used with a rear light box or customer designed retail arrangement with integral lighting.