If you have ever been to a sporting event that has a large - sieve goggle box in the sports stadium , then you have witnessed the mammoth and amazing showing that make the games so much easier to follow . On the TV , they can display instant instant replay , close - ups and histrion profile . You also see these large - filmdom idiot box at subspecies tracks , concerts and in large public area like Times Square in New York City .
Have you ever wondered how they can create a video that is 30 or 60 feet ( 10 to 20 meter ) high ? In this article , we will take a expression at the LED technology that makes these huge displays potential !
Decoding the Signal
A giant TV that is 60 foot ( 20 meters ) gamey has to do the same thing that a normaltelevision setdoes – it has to take a video signal and change over it into full point of visible light . If you have readHow Television Works , then you know how a boob tube that uses acathode ray tube(CRT ) does this . Here is a quick summary of how a black - and - white idiot box works :
[ A color screen door does the same affair , but use 3 separate electron shaft of light and 3 dots of phosphor ( red , green and blue ) for each picture element on the CRT screen . A separate color sign indicates the color of each pixel as the electron beam move across the exhibit . ]
As the negatron beam of light paint across the screen , it is run into the phosphor on the screen with electron . The negatron in the electron beam excite a small dot of phosphor and the cover lights up . By rapidly painting 480 ancestry on the cover at a rate of 30 frames per second , the TV screen allows the center to incorporate everything into a smooth moving image .
CRT engineering works great indoors , but as soon as you put a CRT - based idiot box set outside in undimmed sunlight , you could not see the display any longer . The phosphor on the CRT plainly is not vivid enough to compete with sunlight . Also , CRT presentation are limited to about a 36 - column inch screen . You need a different technology to create a orotund , outdoor screen that is bright enough to vie with sunlight .
Jumbo Screens
There are two with child differences between a jumbo TV screen that you see at a stadium and the TV in your home :
To carry through these feats , almost all tumid - screen outdoor video display uselight emitting diodes(LEDs ) to make the image .
LEDsare , essentially , trivial coloured light source bulbs . Modern light-emitting diode are small , extremely bright and use relatively niggling power for the brightness level that they produce . Other situation you now see LEDs used outdoors are ontraffic lightsand automobile brake lights .
On a semblance CRT television exercise set , all of the colors are produced using red , green and down in the mouth phosphor dots for each pixel on the screen :
In a jumbo TV , red , green and blue LEDs are used or else of phosphor . A " pixel " on a elephantine idiot box is a little module that can have as few as three or four LED in it ( one red ink , one fleeceable and one patrician ) . In the biggest jumbo TVs , eachpixel modulecould have dozens of LEDs . Pixel module typically browse from 4 mm to 4 cm ( about 0.2 to 1.5 inches ) in size .
To work up a gargantuan TV , you take thousands of these LED faculty and stage them in a orthogonal grid . For example , the grid might contain 640 by 480 light-emitting diode modules , or 307,200 modules . The sizing of the ultimate screen depends on the sizing of the LED module :
LED Module Size 4 mm
LED Module Size 25 mm
LED Module Size 40 mm
To control a huge LED covert like this , you expend a computer system , a power controller system of rules and a peck of wiring .
As LED prices have dropped , jumbo TV screens have started to crop up up in all sorts of places , and in all sorts of sizes . You now find LED TVs indoors ( in places like shopping malls and post buildings ) and in all sorts of outside environments – especially areas that appeal lots of tourists .
For more selective information on LED screens and tie in topic , check out out the links on the next pageboy .
