LED TV and LCD TV differences, Local dimming LED TV, Lifespan of TV. etc. explained below
TV specification and features begining with the letter 'L'
LCD full form
LCD stands for 'Liquid Crystal Display'. LCD TVs are Flat Screen TV’s which have millions of Liquid Crystals sandwiched between two glass panels. This assembly is known as the LCD panel. When the liquid crystal elements in the LCD panel are charged with electricity, the crystals “untwist” to let a certain amount of light from the back of the panel through to the people sitting in the front. LCD by itself produces no light, it can either block or let light through. Therefore it requires a backlight to show the picture on the TV.
Difference between LED TV and LCD TV
Actually there is only a minor difference between an LED TV and an LCD TV. An LED TV is basically an LCD TV that has LED bulbs as the backlight. Modern LED bulbs are very bright and small and use less electricity. When LEDs are used as the backlight of an LCD TV, then that TV becomes an LED TV. LED TVs tend to be thinner and use less power than their LCD TV counterparts. This is because in LCD TV, the backlight CCFL tubes have to be placed behind the LCD screen, whereas in an LED TV the LED bulbs can be arranged at the edge of the LCD screen and using reflectors have the backlight fall from behind the LCD screen.
LED Pro and Bright Pro (Philips)
LED Pro and Bright Pro uses local dimming to give high quality pictures but use only about 50% energy. There are over 1000 LEDs which are operated individually as the backlight and are dimmed completely in dark areas to saving energy and at the same time to improve the contrast ratio.
Letterboxing TV Picture:
When a movie shot in CinemaScope with an Aspect Ratio of 2.66:1, is shown on a 16:9 (1.78:1) HDTV, there will be 2 black bars over and below the picture on the TV. This is the Letterboxed effect. When the full width of the CinemaScope movie is fitted to the width TV screen, the height of the movie frame is less than that of the TV screen. Thus the letterboxed effect.
Lifespan of TV, how long will a plasma TV last
All TV loses some of it brightness as the years go by. The lifespan of a flat screen TV is defined as the working time in hours it takes for the screen brightness to become half its original brightness. For example, the answer to the common question of how long does a Plasma TV last, the answer is 60,000 hours. For life of LCD and LED TV, the figure quoted is over 100,000 hours. Assuming 5 hours of TV viewing a day, these figures represent 33 years as the life of Plasma TV and 55 years as the life of LCD TV, same 55 years as the life of LED TV.
Local dimming, Full array local dimming LED TV
In a 'Local Dimming' LED TV, the individual LED bulbs behind the 'LCD Panel' can be dimmed in dark areas of a TV picture and lit bright in areas where there are bright scenes. This arrangement will improve the 'Contrast Ratio' of the LED TV and make blacks appear darker and whites brighter. In a full array local dimming LED TV the LED backlight bulbs are placed on the full area of the back of the LCD screen in neat rows and columns close together and the TV has full control of being able to switch on or off individual bulbs. Full array local dimming LED TV will be the top of the range LED TV of the manufacturers who make it and it will be on the expensive side.
Lumen and LUX:
is a measure of the total amount of visible light emitted by a source.
Lux is the amount of light in a unit area whereas the Lumen above, is the total light coming out of a light source. The unit Lux is described as 1 Lumen per Square Meter. Say for example, you have a light source of 10 lumens lighting up an area of 1 square meter, then the lux is 10 Lm/M2. If the same light source is lighting up 2 square meters, then the lux is 5Lm/M2.