LCD, LED, CRT, TFT, NED – Know them

Posted by Sujit Agarwal | Posted in General, IT Industry | Posted on 17-08-2011

You use it but you don’t know what it is. Well FOURDY is at your service.

Giving a vivid display of the whole thing is not possible but we can try that at least next time when you buy a PC/Laptop you won’t have stand dumb while the salesman keeps speaking words like LED, LCD, CRT, NED and TFT.

Well, what are they?

Cathode Ray Tube (CRT), the technology used in most televisions and computer display screens. A CRT works by moving an electron beam back and forth across the back of the screen. Each time the beam makes a pass across the screen, it lights up phosphor dots on the inside of the glass tube, thereby illuminating the active portions of the screen. By drawing many such lines from the top to the bottom of the screen, it creates an entire screen full of images.

Nano Emissive Display (NED) is the technology that enables manufacturers to design large flat panel displays that exceed the image quality characteristics of plasma and LCD screens at a lower cost. Instead of using either one cathode ray tube (CRT) or millions of tiny LED lights to project a video image, NED uses millions of accelerated electrons charged by just 5 to 10 volts of electricity, compared with 5,000 volts for large-screen, high-definition LCDs. The electrons shoot toward a phosphor plate, creating the moving image. This technique requires less voltage than a CRT. These can be found as large screens in shows and functions which are used as background on the stage.

Thin Film Transistor (TFT), a type of LCD flat-panel display screen, in which each pixel is controlled by from one to four transistors. The TFT technology provides the best resolution of all the flat-panel techniques, but it is also the most expensive. TFT screens are sometimes called active-matrix LCDs.

Basic difference between LCDs and LEDs:

Liquid Crystal Display (LCD): LCD displays utilize 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 them. Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light. This shutter along with the others provides the color which you want.

Light Emitting Diode (LED), an electronic device that lights up when electricity is passed through it. LEDs are usually red. They are good for displaying images because they can be relatively small, and they do not burn out. However, they require more power than LCDs. It consists of tiny bulbs which emit light and these bulbs give a more realistic display as compared to others. It is more power consuming. Local dimming LED display consumes more power than LCD display. Therefore, the tradeoff seems to be between economizing your energy bill and better picture quality. But the edge lit LED displays use less power than an LCD of the same size. Sony, Samsung and Philips have launched LED display models. Similar to LCD monitors, LED screens do not have screen burn-in problem, and are therefore, suitable for computer use.

The LED gives a more a realistic color as compared to LCD. See below:

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