What is HDTV?
What kind of HDTV you buy depends on your needs. Here's a rundown of the current
display technologies. Each one has benefits and limitations, so make your choice based
on the features most important to you.
- CRT -- Direct-view TVs consist of one large CRT tube coated on the front with
phosphors. Rear-projection CRT TVs use three tubes, one each for red, blue and green.
- Pros: The CRT offers the best black level and contrast of all video technologies.
Rear-projection CRT TVs are a real bargain right now.
- Cons: Rear-projection CRT TVs are not very bright, so you need a dark room. They look
distorted when viewed off-angle and the three tubes need to be converged occasionally.
- Plasma -- Despite their large screen sizes (32 to 71 inches), they're ultra-slim. The
least expensive plasmas are usually EDTV (480p) resolution, not HDTV.
- Pros: Bright picture with excellent off-axis viewing angles. Better contrast than LCD
TVs, though not usually as good as CRT.
- Cons: Can suffer from burn-in when a static image is left on for extended periods, though
most new plasmas include features to minimize this risk. Not all plasmas can be used at high altitudes.
- LCD -- Like plasma, LCD TVs are also thin and can be wall-mounted. LCD TVs today are most
common in sizes ranging from 13 to 40 inches, though some 65-inch models are available.
- Pros: LCD TVs don't suffer from burn in. They are brighter than a CRT, but usually not as
bright as plasma. Some LCD TVs are available with 1080p resolution.
- Cons: Some LCDs have poor off-axis viewing. At the moment LCD TV costs much more than an
equivalent sized plasma. LCD TVs usually don't have as good contrast as plasma and CRT.
- DLP -- DLP rear-projection TVs are quickly replacing CRT as the best thing for big screens.
They use a single micro-mirror device and a color wheel from Texas Instruments to create high resolution images.
- Pros: DLPs allow for very slim and light designs. New chip designs offer good contrast and
brightness. DLP TVs and projectors aren't susceptible to burn in.
- Cons: The lamp in a DLP TV will need to be replaced after a few years. Some people are able to see
rainbow color artifacts caused by the TV's color wheel.
- LCoS -- Like DLP, LCoS TVs are available in rear-projection format. LCoS TVs use three tiny
reflective LCD panels to create a picture. The technology also goes by SXRD (Sony) and D-ILA (JCV).
- Pros: Like DLP, LCoS rear-projection TVs are much thinner than traditional CRTs. They can be bright
with big contrast. The high fill-rate of the pixels mean you can sit a bit closer.
- Cons: Like DLP, they have a lamp that will need to be replaced after a few years. They can't be
hung on a wall like plasmas but they cost less.
What's the difference between enhanced definition (EDTV) and high-definition (HDTV)?
- HDTV includes picture resolutions of 1,080 interlaced and 720 progressive and 1,080 progressive. EDTV resolution
is 480 progressive, equivalent to the video output of progressive scan DVD players. EDTV looks much better than
today's standard analog, but shouldn't be confused with true HDTV.
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