LED TVs -- the name given to LCD screens with an LED backlight -- are available with increasingly fast refresh rates; but faster isn't always better. Just because an LED TV has a fast refresh rate -- which is measured in hertz -- doesn't mean you need all that extra speed.
What's An LED TV?
The term LED TV is itself a misnomer; these televisions actually use LCD -- short for liquid crystal display -- technology to generate the tens of thousands of colors you see on your TV screen. The LED portion of the name comes from the backlight. While many older LCD TVs on the market use cold-cathode fluorescent lamps for backlights, others use the newer LED technology. Short for light-emitting diodes, LEDs require less energy to run, reducing a user's electricity bill. They also come in a variety of styles, including full-array with and without local dimming, which can lead to truer blacks than LCD TVs using CCFL backlighting.
Refresh Rate Explained
The terms 100Hz and 200Hz refer to a television's refresh rate. Measured in hertz, the refresh rate refers to how frequently the TV updates the picture on the screen. The faster the refresh rate, the more frequently your TV receives this data. The term 100Hz means a TV refreshes the picture data 100 times per second; in other words, you're seeing 100 frames every second. A 200Hz refresh rate means your TV is refreshing the picture data received from the source twice as often, or 200 times a second.
Does Refresh Rate Matter?
In theory, a faster refresh rate should mean a clearer picture with less blurring; this is a common knock on LCD televisions from critics, who say that LCD TVs -- and LCD TVs with LED backlights -- don't broadcast fluid images, especially during high-action events like sports or adventure movies. But the standard rate of data transmission for American television is 60Hz, or 60 frames per second. Whether you're viewing this programming on a 100Hz or a 200Hz LED TV, your television is forced to extrapolate the data it receives from the source to create frames that aren't original to the source.
Features That Do Matter
While increasingly fast refresh rates can sometimes be extraneous, other features available on LED TVs that go hand in hand with refresh rates are not. One of these key features is progressive and interlaced scanning, symbolized by the "p" and "i" letters after a TVs resolution -- for example, 1080i or 720p. "P" refers to progressive scanning; if you're watching a show on a 100Hz LED TV that uses progressive scanning, you are truly seeing 100 frames per second. That's because progressive scanning scans the entire frame at once. Interlaced scanning, however, splits each frame into two; if you were watching a show on a 200Hz LED TV that uses interlaced scanning, you're seeing two versions of each frame -- in other words, the picture on a 100Hz progressive scan TV will look almost identical to the picture on a 200Hz interlaced scan TV.