Chances are, you still own a TV that is bulky, has a picture tube and is kept on a table. Well, with advancing technology, TVs have become slimmer and lighter, can hang on the wall and do not have a bulky picture tube.
The new TVs have an LCD or a Liquid Crystal Display in place of the earlier picture tube. Now, unlike the picture tube, LCDs have no light of their own, and have to be lit with a backlight. Until recently, most LCD TVs were backlit with plasma discharge tubes or CCFL lamps.
The CCFL lamps are placed directly behind the LCD panel and this adds to the overall thickness of the TV. Another newer method of lighting up the LCD panel is with LEDs and these are placed all around the panel, just beneath the bezel of the screen. Some models, especially the larger sized TVs place the LEDs behind the panel.
According to the TV manufacturers, LED models provide a better contrast (difference between black and white parts of the picture). This is because LEDs can be turned off completely to render a complete black portion. With CCFLs, there was no turning off, and the blacks produced were not so deep.
With further advancement of technology, there is a new kid on the block, called OLED or Organic Light Emitting Diode. This is a thin layer of film made from an organic compound which emits light in response to an electric current. Unlike an LCD, an OLED screen needs no backlighting, making it the thinnest of all the screens for a TV; a screen, which can be rolled up.
Other advantage of OLEDs is its very high switching speed, which produces practically no blur when there is fast movement in the picture. Moreover, OLEDs can be switched off to produce black color, and there is no leakage of light from the neighboring OLEDs. This allows OLEDs produce the highest dynamic contrast among all the displays. Does that mean OLEDs are better than LEDs?
As the technology is relatively new, there are some primary difficulties that OLEDs face today. The first is OLEDs are still not as bright as LEDs are, and that makes them harder to see in sunlight or even in broad daylight. Additionally, with the present structure of the OLEDs, producing blue light is harder. This makes the images just passable.
Another issue with the OLEDs is their lifespan. At present, the OLED has the shortest lifespan among LED, LCD and other technologies commonly available on the market. The average lifespan of an OLED is only 14,000 hours, which means if you watch eight hours of TV every day, the OLED screen will last only five years.
Although OLEDs are good at displaying high contrast, they hog quite a bit of power when displaying all whites. Moreover, similar to the old cathode ray tubes or picture tubes, OLEDs are prone to burn-in, meaning if you let the picture remain static for long, a shadow of the picture remains on the screen.
The last disadvantage of OLEDs is their prohibitive cost.
