Why do LCDs use less electric power than many other display technologies?

Liquid crystal displays (LCDs) are highly efficient because they do not emit their own light; instead, they function by modulating external light through a layer of liquid crystal.1

The primary reason for their low power consumption is that the electro-optical fluid used in these displays acts as an electrical insulator. When an electric field is applied to change the orientation of the liquid crystal molecules—thereby altering the light-transmitting properties of the display—very little electric current flows through the assembly. Because the material itself consumes almost no power to switch states, the technology is exceptionally well-suited for battery-powered devices.2

In contrast, other display technologies like the cathode-ray tube require high voltages and large currents to operate, and plasma display panels require significant power to ionize gas and generate light. While LCDs do require a separate source of illumination, such as a backlight, their fundamental mechanism for controlling pixels remains significantly more energy-efficient than emissive display technologies.13