Just in case you were wondering, there is no liquid in a Liquid-Crystal screen, and no blood products in a plasma screen. Both refer to the substance within that changes it’s physical state in order to produce a picture.
LCD screens have taken over in nearly all TVs and computer monitors. These are lightweight and fairly robust, but the screen surface is typically very soft and easily damaged. They should be cleaned only with a small amount of water or rubbing alcohol on a soft cloth. Make sure before you buy that you watch some kind of fast action on an LCD. Some of them have a slow response time, causing streaking or other artifacts on fast- moving images. Look at the Refresh Rate. This is the rate at which the TV redraws the picture. 60 Hz (Hertz) means 60 times per second. If you like to watch anything with fast action, shop for a refresh rate of at least 120 Hz.
LCD displays work by transmitting light through the screen. The LCD itself is all solid-state and will probably last a lifetime. The lamp that actually produces the light, however, can go bad after a while. The life span of the lamp is typically equivalent to watching TV 8 hours a day for 10 years or more, so they are very reliable. Most manufacturers do not have replaceable lamps in their LCD screens. LCD is immune to screen burn (The tendency for a stationary image to “burn” itself into the screen, causing a permanent ghost image), unlike Plasma or CRT. LCD is the best choice for most folks, unless you’re on a very tight budget, in which case, look at Plasma.
An LED TV is the newest twist. This is still an LCD TV, but the lamp has been replaced by solid-state LEDs, which use less power and should last a lifetime. It’s claimed that the color is better, too. Most LCD TVs will be LED in another couple of years.
Plasma TVs may cost less than a comparable LCD. A plasma picture is the brightest and has the highest contrast ratio (The ratio between the darkest black and the brightest white) of anything except a CRT. They don’t have a problem with fast action or viewing angle because a Plasma TV produces it’s own light. A Plasma TV is like a series of tiny fluorescent lamps – One for each pixel. The only drawbacks are their fragility, higher power consumption, and greater weight. They must be carefully handled because they are mainly a large sheet of very thin glass. They do, however, have a harder screen surface than LCD screens, and thus are easier to clean. Always follow the manufacturer’s instructions for cleaning any big-screen TV.
Projection TVs used to be quite popular, but as LCDs and plasmas became larger and cheaper, projection sets mostly faded away. You won’t see many of these unless you’re shopping for a 120-inch monster.
The DLP (Digital Light Processing) projection TVs are the latest and supposedly the best. They work by reflecting the light from the projector lamp off of a series of tiny hinged mirrors that pivot hundreds of times a second. The longevity of these units is very good, requiring only an occasional replacement of the projector lamp. The lamp should last several years under average use, which is good because they cost around 300 dollars. There is some discussion of whether the DLP or LCD TVs have better color rendition. Some people report that DLP sets have annoying color fringes. Always look at the unit in similar lighting to your living room (Or wherever you plan to use it) before making a buying decision.
Next Time: TV connections
This post has been adapted from my new book, “Deciphering the 21st Century,” Available now! Click here to read all about it.
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