LCD Full Form
Full Form of LCD?
LCD - Liquid Crystal Display
A liquid crystal display (LCD) is a flat and thin panel, used for displaying information on watches, phones, monitors for computers, televisions and numerous other electronic devices. Among its major features are its lightweight construction, portability, and ability to be produced in much larger screen sizes than are practical for the construction of cathode ray tube (CRT) display technology. LCD utilize two sheets of polarizing material with a liquid crystal solution between them through which an electric current is passed. It gives better clarity and efficiency as compared to the old cathode ray tube (CRT) monitors.
LCD is used in the wide range of devices, including :-
- Digital watches
- Instrument panels
- Aircraft cockpit displays
- Portable computers
- Gaming devices
- Mobiles and PDAs
- Computer monitors
- Video players
- Clocks and more
Advantages of LCD over CRT
While the LCD's predecessor, the CRT--or Cathode Ray Tube, is still used for many applications, there are many differences between the two. Some advantages of LCDs over CRTs and plasma type displays are as follows:
- Screens are available in a broader range of sizes
- Do not rely on phosphors
- Immune to screen image burn-in
- Uses small, pixelated format
- Energy efficient, low-power
- Lightweight and compact
- Easy disposal
- Superior resolution and sharper image
- Can be used in battery-powered electronics
History of Liquid Crystal Displays
- In 1888, liquid crystals were first discovered in cholesterol extracted from carrots by Austrian botanist and chemist, Friedrich Reinitzer.
- In 1962, RCA researcher Richard Williams generated stripe patterns in a thin layer of liquid crystal material by the application of a voltage. This effect is based on an electrohydrodynamic instability forming what is now called “Williams domains” inside the liquid crystal.
- According to the IEEE, "Between 1964 and 1968, at the RCA David Sarnoff Research Center in Princeton, New Jersey, a team of engineers and scientists led by George Heilmeier with Louis Zanoni and Lucian Barton, devised a method for electronic control of light reflected from liquid crystals and demonstrated the first liquid crystal display. Their work launched a global industry that now produces millions of LCDs."
- Inventor James Fergason holds some of the fundamental patents in liquid crystal displays filed in the early 1970s, including key US patent number 3,731,986 for "Display Devices Utilizing Liquid Crystal Light Modulation"
- In 1972, the International Liquid Crystal Company (ILIXCO) owned by James Fergason produced the first modern LCD watch based on James Fergason's patent.
CRT : Cathode Ray Tube
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.
NED: Nano Emissive Display
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.
TFT: Thin Film Transistor
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.