Britannica Sources used in this answer

How do red, green, and blue filters produce colour images on an LCD?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Diagram comparing three liquid crystal phases: nematic with parallel rods aligned vertically, smectic A with rods arranged in horizontal layers, and smectic C with rods in tilted layers. — liquid crystal display Liquid crystal arrangements
In nematic arrangements the crystals are randomly positioned with all their long axes pointing in essentially the same direction, given by a vector known as the director. In smectic arrangements the crystals are further constrained to parallel planes; in smectic A the director is perpendicular to these planes, while in smectic C the director is at some other angle to the planes.

In a colour liquid crystal display (LCD), images are produced by utilizing three distinct sub-elements for each pixel. Each of these sub-elements is equipped with its own primary-colour filter—red, green, or blue.1

Because LCDs do not emit their own light, they rely on a backlight source to illuminate the display. By applying a varying electric voltage to the liquid crystal layer, the display controls the amount of light that passes through each specific colour filter. By modulating the intensity of light transmitted through these red, green, and blue filters, the device can combine these primary colours in varying proportions to create a full-colour image.12

Alternatively, some advanced systems use time-sequential colour, where a coloured backlight flashes red, green, and blue in rapid succession, eliminating the need for static colour filters.3