LED vs. LCD

An LED is a semiconductor device that emits visible light when an electric current passes through it. The light is not particularly bright and usually monochromatic, occurring at a single wavelength. The LED light output range is from infrared and red to blue-violet. The LCD is a type of display used in digital watches and many portable computers that utilizes two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causes the crystals to align so that light cannot pass through, each crystal acting like a shutter, either allowing light to pass through or blocking the light.

What is the difference in energy requirements in the operation of a light-emitting diode (LED) and a liquid crystal display (LCD)? After all, they both require energy to operate. And how is a plasma display different from both of them in its energy requirements?

Answer

We assume that they all have the same resolution, and we know that all three types of display LED, LCD, and plasma require energy to operate. But the majority of the energy for the LCD is provided by the ambient light, whereas all the energy for the LED and plasma displays must be provided by the electronic power source itself, such as a battery or the AC supply. In addition, considerable thermal energy can be produced in a plasma display, an energy requirement beyond simply producing a picture on the screen. Of course, there are LCD displays that must provide their own ambient light if they are to be used in a dark environment, so these displays have additional energy requirements when operated in this manner.

So LCDs consume much less power than LED and gas-display models because LCDs work on the principle of blocking light rather than emitting it.