DIFFERENT TECHNOLOGIES IN MODERN TELEVISION(LED LCD AND PLASMA)

Buying a new TV is not an easy task because of the different marketing terminology used by companies to fool consumers. In midst of these terms, selecting a tv is a daunting task. This is made even difficult by the sales persons present in the stores who give misleading claims about the TV technology s that they may meat target. So without any further ado lets dive into the different technologies used in the modern television.
First of all to get to know a bit more about displays where you would know about different display resolutions and brief overview about different display technologies. In this post I am going to tell you about the display technologies use in modern day televisions. So let's get started.

LCD TVs:

LCD stands for, as you may know, Liquid Crystal Display technology. It is the most extensively used technologies in modern day televisions. Millions of individual LCD shutters, arranged in a grid, open and close to allow a metered amount of the white light through. Each shutter is paired with a colored filter to remove all but the red, green or blue (RGB) portion of the light from the original white source. Each shutter–filter pair forms a single sub-pixel. The sub-pixels are so small that when the display is viewed from even a short distance, the individual colors blend together to produce a single spot of color, a pixel. The shade of color is controlled by changing the relative intensity of the light passing through the sub-pixels. These are of two types and are further divided into these two classes:

• PASSIVE MATRIX:
  These were basically used in earlier devices with a monochrome display. Passive-matrix LCDs are still used today for applications less demanding than laptops and TVs. In particular, these are used on portable devices where less information content needs to be displayed, lowest power consumption (no backlight) and low cost are desired, and/or readability in direct sunlight is needed.
• ACTIVE MATRIX DISPLAY:
  These are the most common type of LCD displays used in modern televisions and other devices which require a colour display. Different AMDs have been already explained in my earlier post. 

Further, LCD can be differentiated on the basis of bulbs used in hem for lighting the pixels:

• CCFL: The LCD panel is lit (usually) by two cold cathode fluorescent lamps placed at opposite edges of the display. A diffuser and two polarizers then spread the light out evenly across the whole display. For many years, this technology has been used almost exclusively. Unlike white LEDs, most CCFLs have an even-white spectral output resulting in better color gamut for the display. However, CCFLs are less energy efficient than LEDs and require a somewhat costly inverter to convert whatever voltage the device uses (usually 5 or 12v) to the high voltage needed to light a CCFL. The thickness of the inverter transformer also limits how thin the display can be made.
• EL-WLED: The LCD panel is lit by a row of white LEDs placed at one or more edges of the screen. A light diffuser is then used to spread the light evenly across the whole display. As of 2012, this design is the most popular one in desktop computer monitors. Some LCD monitors using this technology have a feature called "Dynamic Contrast" where the backlight is dimmed to the brightest color that appears on the screen, allowing the 1000:1 contrast ratio of the LCD panel to be scaled to different light intensities, resulting in the "30000:1" contrast ratios seen in the advertising on some of these monitors. Since computer screen images usually have full white somewhere in the image, the backlight will usually be at full intensity, making this "feature" mostly a marketing gimmick.
• An LED-backlit LCD display is a flat panel display which uses LED backlighting instead of the cold cathode fluorescent (CCFL) backlighting used by most other LCDs.[1] LED-backlit LCD TVs use the same TFT LCD (thin film transistor liquid crystal display) technologies as CCFL-backlit LCD TVs. Picture quality is primarily based on TFT LCD technology, independent of backlight type.
  WLED array:
  The LCD panel is lit by a full array of white LEDs placed behind a diffuser behind the panel. LCD displays that use this implementation will usually have the ability to dim the LEDs in the dark areas of the image being displayed, effectively increasing the contrast ratio of the display. As of 2012, this design gets most of its use from LCD televisions.
  Dynamic “local dimming” LEDs:This method of backlighting allows local dimming of specific areas of darkness on the screen. This can show truer blacks, whites and photorefractive effects[4] at much higher dynamic-contrast ratios by dimming (or brightening) the backlight locally (at the cost of less detail in small, bright objects on a dark background, such as star fields or shadow details).

  

  LED-LCD TLEVISION

  
                                       

PLASMA:

A panel typically comprises millions of tiny cells in between two panels of glass. These compartments, or "bulbs" or "cells", hold a mixture of noble gases and a minuscule amount of mercury.With flow of electricity (electrons), some of the electrons strike mercury particles as the electrons move through the plasma, momentarily increasing the energy level of the molecule until the excess energy is shed. Mercury sheds the energy as ultraviolet (UV) photons. Depending on the phosphors used, different colors of visible light can be achieved. Each pixel in a plasma display is made up of three cells comprising the primary colors of visible light. Varying the voltage of the signals to the cells thus allows different perceived colors.

PLASMA TV

This should give you an idea about the different technologies present in the market right now. Stay tuned to this space as I would be telling you the difference in LCD and PLASMA TVs and would help you decide which TV to go for. I would clarify the myths and decode the marketing gimmicks to show you the true story behind TVs. So stay tuned.


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