Everyone loves to watch their favourite shows and sports programs on the largest flat screen TV they can find, but did you know that not every TV uses the same technology? If you've been paying attention to the latest ads for TVs, you may have heard about a new type of TV using LED technology. So, what's the difference between an LED TV and an LCD TV?

LCD stands for liquid crystal display, while LED stands for light emitting diode. LCD-based displays can be found everywhere, from the small screens on cell phones to large electronic billboards. The liquid crystals (the LC part of LCD) in these displays do not emit any light, but their orientation changes when an electrical current is applied, blocking light in various degrees to produce many shades of grey. But who wants to watch TV in shades of grey? In modern colour LCD displays, each pixel is made up of three separate liquid crystal cells that are arranged behind filters to allow each cell to produce shades of red, green, or blue. Together, these cells generate the thousands of colours visible on TV.

Did you know? Every pixel in an LCD display is made up of three liquid crystal cells, one red, one green and one blue.

LEDs are made by placing a semiconductor material between two electrical terminals. Unlike liquid crystals, LEDs can emit light when a charge is run between the terminals. Using different semiconductor materials, LEDs emitting different coloured lights can be made. You might be tempted to think that LED TVs are just a panel of LEDs emitting different colours to make up the pictures you see, but you would be wrong! Most LED TVs that we can buy today are actually LED backlit TVs, which simply use LCD panels whose pixels are lit up by LEDs in the back.

Did you know? LED backlit TVs use less energy than conventional LCD TVs.

The advantage of these LED TVs over conventional LCD TVs, is that the use of fluorescent backlighting reduces energy usage and provides better colour contrast. Sony has recently introduced a TV using true LED displays, but this TV costs over $2,500 for an 11 inch screen!

Learn More!

http://en.wikipedia.org/wiki/Liquid_crystal_display

http://en.wikipedia.org/wiki/Light-emitting_diode

http://en.wikipedia.org/wiki/LED_TV

David He

I am a PhD student in Molecular Genetics at the University of Toronto. In my spare time, I enjoy photography and watching movies.


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