How LCDs Work
In an LCD (Liquid Crystal Display), each pixel is located at the intersection of two layers of polarised glass. The control of light at these intersections allows pixels to appear either dark or illuminated, giving the impression of being turned “on” or “off.”
The key to this control lies in the behaviour of the liquid crystals between the two glass layers. In their natural state—without an applied electric charge—the liquid crystals are twisted. This twist alters the angle of the incoming light to align with the orientation of the second (top) polarizing layer, allowing light to pass through and making the pixel appear bright.
When an electric charge is applied to a pixel, the liquid crystal structure untwists. As a result, the light no longer rotates and is blocked by the top layer of polarised glass, which is oriented perpendicular to the bottom layer. This prevents light from passing through that area, making the pixel appear dark.
The display’s controller circuitry determines which pixels are activated or deactivated. These controllers interpret input signals—such as text or image data—and translate them into pixel-level instructions, activating specific pixels to form characters, graphics, or images based on predefined patterns or fonts.