If you have ever seen a jumbo TV screen at a sporting event or on a public screen, you’ve surely been in awe that the technology exists for such a large screen to work.
A jumbo TV screen works basically the same way a smaller, home television set does—it has to read a video signal and convert it into different amounts of light so that we can see the picture on the screen. A home color TV set does this by sending electron beams across the screen at very quick time intervals and a device called a cathode ray tube (CRT) reads the video signal and energizes small amounts of phosphor in the screen to show where the light is in the picture we should be seeing. Another signal is sent to read the color with three electron beams and three different colors of phosphor: red, green and blue. Each pixel on the TV screen has these three colors present and the video signal indicates which color to display in that pixel.
A problem that arises when making a jumbo TV screen is that most jumbo screens are located outdoors, and the CRT simply cannot produce enough light to overpower the sunlight and the picture is washed out and cannot be seen clearly. For an outdoor screen, light emitting diodes (LEDs) are used to make the light much brighter than an indoor screen so that we can see the image, even in bright sunlight.
Basically, a LED is a tiny, colored light bulb that uses only a tiny amount of power to create a very bright light. On a jumbo TV screen, red, green and blue LEDs are used in place of the phosphor of the home television set. To create the pixel system of a home TV set, the jumbo TV screen is divided into what are known as pixel modules, which range in size from 4 mm to 4 cm and can contain in them dozens of LEDs.
Thousands of these pixel modules are arranged on a rectangular grid. In order to operate such a large set of LEDs, both a computer system and power system are needed to run it, as well as many, many wires behind the screen, as it takes several wires to run each LED.
The computer system will read the video signal for the intensity of brightness and the color of the image and then decides which LEDs will be lit and how bright they should be.
The power system ensures that each LED is receiving the correct amount of power to operate properly. The typical jumbo TV screen can use up a lot of power—to the tune of 1.2 watts of power per pixel. A 20 meter jumbo screen might use as much as 300,000 watts all together.
The popularity of using LEDs in television screens is growing, because the price of LEDs has gone down considerably in recent decades. And they are not limited to the enormous screens you might seen at a football stadium or in Times Square, but are now being used for smaller screens (but still much larger than a home set) and even indoors. As the technology improves, your next home television set could be quite large and could have an LED powered image.
