Four styles of HDTV

By David Katzmaier
(March 18, 2003, updated September 30, 2008)

Once upon a time, when only analog, tube TVs were around, buying a new set was a whole lot less of a nerve-racking experience. Now, there are all sorts of questions. Is LCD better than plasma? Is it worth it to go 1080p? And what about rear-projection? If all the tech jargon has you confused, don't worry. Read our guide to the pros and cons of high-tech TVs, and you'll feel a whole lot more confident when you hit your local electronics store.

Types of HDTV: Direct-view (tube) TVs | Flat-panel plasma and LCD TVs | Rear-projection TVs | Front-projection TVs

Direct-view (tube) TVs

	Upside:		Downside:		Forecast:
	Relatively inexpensive.		Bulky and heavy; limited screen size; lower resolution; usually incapable of displaying HDTV sources; rarely PC-compatible.		Tube TVs are becoming uncommon in stores, but this technology still has a few years left before it dies completely.

With almost no HDTV-capable versions available, and most sellers keeping screen sizes under 27 inches, the tube TV is officially on its last legs.

The tube TV is a rare breed in electronics stores these days. Walk into any big-box retailer and you'll find them in the corner, if you find them at all, labeled "Standard-definition digital TV" and bearing a name like Dynex or Haier. These sets are, by law, equipped with digital tuners to receive DTV stations over-the-air, but they won't display anything near high-definition video quality. The few HDTV-compatible tubes are priced at levels similar to LCDs with the same screen size, so they're not very popular.

Direct view is how industry insiders refer to any television that doesn't use projection technology. They're called tubes because the glass forms the business end of a cathode-ray tube (CRT). Direct-view tube TVs can be found in sizes up to 36 inches (diagonal), and as their screen sizes increase, so do their heft and depth. The largest models in the mid-30-inch range can weigh nearly 200 pounds and measure two feet deep. Because of size and weight issues, it doesn't pay for companies to make larger tube TVs; they simply aren't practical.

We're not going to go into too much detail about tubes because we just don't recommend them for most TV shoppers. Unless you're on a very tight budget and don't care about high-definition, it's worth it to step up to a newer TV technology.

Next: See Flat-panel plasma and LCD TVs

See other types of HDTV:
Direct-view (tube) TVs | Flat-panel plasma and LCD TVs | Rear-projection TVs | Front-projection TVs

Flat-panel TVs: plasma, LCD, and how they compare

The biggest television technology revolution since color, flat-panel plasma and LCD TVs are well on their way to replacing tubes as the TV technologies of choice. You can hang flat sets on the wall, on the ceiling, or above the mantle in place of a trophy buck--although most people just put 'em on stands. The two major types of flat-panel TVs are plasma and LCD, so we'll go over each type separately and then compare them in a chart at the end.

Plasma

	Upside:		Downside:		Forecast:
	As little as 3 inches thick; very good home-theater image quality in best examples; wide viewing angle; superior motion resolution.		Less energy-efficient than LCDs; slight potential for burn-in; sometimes lower native resolution than similarly sized LCDs.		Prices have fallen, and pictures have improved dramatically, perpetuating plasma's place as king of the flat-panel home-theater hill.

With prices starting about $700 for the least expensive models, a coveted plasma TV is within reach of most shoppers. But now that you can get a 42-inch LCD for a similar chunk of change, plasma TVs have to depend on factors other than price to remain competitive. One area where plasma still reigns, however, is in very large screen sizes. Today's 50-inch plasmas--the plasma TV sweet spot--are still less expensive than similarly sized LCDs, and in even larger screen sizes the gap widens considerably. That said, big-screen plasmas are still a solid chunk of change more than rear-projection sets.

Pioneer's PRO-111FD, a high-end plasma, is the best-performing flat-panel TV CNET has ever tested.

Picture quality varies greatly between different makes and models of plasma TVs, so be sure to read reviews before you plunk down your cash. The best plasmas produce top-notch image quality, with deep black levels, excellent color, wide viewing angles, and better motion resolution than similar LCDs, making them subject to less blurring during fast movement. On the flip side, many people don't notice LCDs' blurring, so it's not as big of a difference-maker as many marketing campaigns would have you believe.

Although 1080p native resolution is common among plasmas and LCDs, the latter often have higher native resolution than plasma TVs at similar screen sizes. In the real world, however, the difference just isn't that noticeable.

One distinct advantage LCD has over plasma is in the arena of power consumption. Per square inch of screen, plasmas almost always use more power than LCDs to produce the same picture brightness. Check out our TV power consumption guide for more details.

Burn-in: You may have heard that plasma has a couple of drawbacks. One such downside is burn-in, which occurs when an image--such as a stock ticker, a network logo, or letterbox bars--gets etched permanently onto the screen because it sits in one place too long. In our experience, the danger of burn-in has been greatly exaggerated, and people with normal viewing habits have nothing to worry about. The potential for burn-in is greatest during the first 100 or so hours of use, during which time you should keep contrast low (less than 50 percent) and avoid showing static images or letterbox bars on the screen for hours at a time. After this initial phase, plasma should be as durable as any television technology. Many models also have burn-in-reduction features, such as screensavers and pixel orbiting, or settings to treat burn-in once it occurs, such as causing the screen to go all white. Check out our guide to burn-in for more details.

Plasma life span: The life span of plasma TVs is another area that's improved dramatically with the last few generations of the technology. Partly in response to claims made by LCD TV makers, plasma manufacturers now claim their panels last an extremely long time. Most plasma makers today claim a life span of 60,000 hours before the panel fades to half brightness. That's more than 20 years if the TV is on for 8 hours per day.

LCD

	Upside:		Downside:		Forecast:
	Available in a range of sizes; matte screens generally reflect less light; no danger of burn-in.		Home-theater image quality generally not as good as on plasma models; relatively narrow viewing angle.		Flat-panel LCDs will continue to be the most popular HDTV technology, thanks to falling prices and plenty of choices.

The Samsung LN52A650 is a 52-inch LCD with deep black levels, accurate color, 120Hz processing and a shiny screen.

Flat LCDs are extremely popular in all screen sizes these days, thanks to competitive pricing and the fact they can fit just about anywhere. Larger LCDs--as big as 65 inches--remain more expensive than plasma and rear-projection models, but in the popular 40- to 42-inch size range, LCD prices have dropped precipitously. As of fall 2008, flat-panel LCDs in this size range can be had for as little as $750, just a bit more than plasmas.

The picture quality of LCD TVs has historically suffered from poor black levels, but the latest versions are often much-improved. The best plasmas still surpass the best LCD in terms of delivering a deep black, however, and in general LCD still lags behind. That's because LCDs use a backlight to provide illumination, and there's almost always some light leaking through the pixels. Color saturation is also generally inferior to plasma's, again as a result of the inability to completely blacken (turn off) the pixels. New LCD technologies, including LED backlights, are helping even the playing field, but they're still extremely expensive.

Viewing angle is another weakness of LCD compared with plasma. On every LCD we've reviewed, we witnessed some brightness and color shift visible when we watched from an angle that's more or less removed from the sweet spot right in front of the TV (to either side, and especially above or below). Plasmas look equally good from very wide angles. In addition, LCDs are much more likely to exhibit uniformity problems than plasmas, which can appear as lighter areas on dark screens, clouding, or even color banding on some models. These can be more or less severe from model to model, so check the individual reviews for comments.

On the other hand, LCDs will generally have a higher native resolution than plasmas of the same size. This isn't as big a deal as you might think because, in practice, it's difficult for the average viewer to discern the difference between, say, a 40-inch LCD with 1080p resolution and a 42-inch plasma with 1,024x768 resolution, especially from normal seating distances (more info).

LCD specification sheets often talk about response time, but in our experience, almost all newer LCDs have adequate response time to deal with fast motion to the satisfaction of most viewers. A related issue is motion blur, which can occur in fast-moving images. LCD TVs with a 120Hz refresh rate can alleviate some of that blurring, but they're generally still not as blur-free as plasmas. It's also worth noting that many people don't notice motion blur at all. 120Hz LCDs often have dejudder processing too, which smoothes out judder in images but can also make some material look more-artificial.

LCDs also have a reputation for being brighter than plasmas, and while that's technically true, most plasmas are plenty bright for even the most demanding situations. One definite advantage of LCD TVs, however, is that their matte plastic screens reflect less ambient light than plasmas' glass, so they're usually better for very bright rooms with little light control. Note that some LCDs have glossy screens, as opposed to matte.

Plasma vs. LCD

Want a quick and dirty comparison between plasma and LCD? Here it is, but for full explanations feel free to start at the top.

	Plasma	LCD
General
Screen sizes	42 inches to 65+ inches	5 inches to 65+ inches
Cabinet depth	3+ inches	3+ inches
Power consumption (more info)	Slightly less efficient per square inch	Slightly more efficient per square inch
Price	Usually less expensive for screen sizes over 42 inches	Usually more expensive for screen sizes over 42-inches
Features
PC connectivity	Less common but still included on many models	More common than on plasma TVs
Other features	Varies per model	Varies per model
Picture quality
Motion blur caused by display	Negligible	Difficult to discern on most models, although subject to more blurring than plasma. 120Hz models subject to less motion blur
Black-level performance (depth of "black" displayed)	Varies, although excellent on many models.	Varies, although generally worse than plasma on many models
Color saturation	Varies, although generally a bit better than on LCDs due to black-level and off-angle advantages	Varies, although the best models can equal the best plasma TVs
Resolution (more info)	Typically 720p, up to 1080p on high-end models. The benefits of 1080p are not obvious at screen sizes less than 50 inches to the majority of viewers.	Typically 720p, but 1080p is more common than on plasma TVs, at more price and size points. The benefits of 1080p are not obvious at screen sizes less than 50 inches to the majority of viewers.
Off-angle viewing	Excellent from all angles	Image fades slightly when seen at extreme angles from sides or from above or below
Reflectivity of screen	Glass screens can reflect lots of light, so may be an issue in very bright rooms. Some models have glare-reducing screens that are more or less effective.	Matte-plastic screens usually reflect less light. Some models have screens that are actually more reflective than plasma TVs.
Durability
Burn-in (faint after-images left on the screen; more info)	Possible with still images left onscreen with very bright settings for hours, although new models are much less susceptible, and most burn-in is temporary and goes away after watching moving images.	Occurs only in extreme circumstances
Life span (hours until brightness fades by half)	Typically 60,000 hours, or about 20 years if used 8 hours per day	Typically 60,000 hours, or about 20 years if used 8 hours per day
Performance by program type
HDTV	Excellent, although the rare EDTV models can look a bit softer because of lower resolution	Excellent for HDTV-compatible models
Standard-definition TV	Dependent mostly on screen size. The smaller the screen, the better standard-definition sources usually look.	Dependent mostly on screen size. The smaller the screen, the better standard-definition sources usually look.
DVD movies	Excellent given a model with good black-level performance	Very good, although models with worse black-level performance are less desirable
Games	Excellent for most users, although burn-in might deter gamers who leave screens paused for hours or overnight	Excellent, although motion blur might deter the most sensitive gamers

Next: See rear-projection TVs

See other types of HDTV:
Direct-view (tube) TVs | Flat-panel plasma and LCD TVs | Rear-projection TVs | Front-projection TVs

Rear-projection TVs

Thinking of going big? Rear-projection HDTVs still offer the biggest screen for your buck, although falling prices among big-screen plasmas--58 inches and up--are forcing RPTV makers cut prices on their own. It's pretty obvious, in fact, that eventually RPTVs will go the way of the dodo as flat-panel HDTVs take over completely, but we're still a couple years away from that. Rear-projection sets start at a sizeable 50 inches and go up from there.

A sea change has been happening in the rear-projection market as this TV type loses ground to flat panels: makers are dropping out. Heavy hitters Sony, Toshiba, and Hitachi no longer manufacture rear-projection sets, leaving only Mitsubishi and Samsung with significant lineups among major names. Both utilize DLP technology--former rear-projection stalwarts LCD and LCoS are no longer widely available.

Microdisplays

Microdisplays are slimmer than older CRT-based rear-projection HDTVs, but still fatter than flat-panels.

"Microdisplay" refers to any rear-projection HDTV that uses one or more microchips--again, DLP is the only one currently being manufactured--festooned with thousands or a just over a million pixels as part of a light engine. The light engine is driven by a lamp that bounces light off of chip, through an assembly that produces color, and onto the big screen. Below is a brief look at how microdisplays differ from standard televisions.

-- The lamps inside these sets, which cost $200 and more, must be replaced every 3,000 to 6,000 hours, depending on conditions of use. You can replace most lamp assemblies yourself.
-- The lamps take from 20 seconds to a minute to warm up and cool down. During the warm-up phase, the image is either dim or completely dark.
-- The TVs are lighter and slimmer than older CRT-based rear-projectors, and you almost always need a stand to get them at eye level.
-- Unlike older CRTs, all microdisplays can get quite bright without losing detail, so they're perfectly viewable in brightly lit rooms.

DLP

	Upside:		Downside:		Principal brands:		Forecast:
	Less-expensive at very large screen sizes than plasma; good black-level performance on the best models.		Lamp requires periodic replacement; thicker and bulkier than flat-panels; rainbow effects; less-impressive off-angle performance than plasma		Mitsubishi, Samsung		DLP is only getting cheaper as flat panels get bigger, and the best examples deliver excellent image quality and great value.

Samsung's HL61A750 DLP TV uses LEDs instead of a conventional bulb.

DLP was developed by Texas Instruments, and the company sells its chips, known as Digital Micromirror Devices (DMDs) to numerous manufacturers, including Samsung and Mitsubishi in the rear-projection arena. The DLP chip has thousands or just over a million tiny mirrors that flip back and forth to control light output.

Most DLP sets available today have 1080p resolution, and all use a technique "wobulation" to achieve their stated native resolutions. With wobulation, which Samsung calls SmoothPicture, the DLP chips have half as many mirrors, or physical pixels, as the stated native resolution (a 1080p chip has 960x1,080 pixels/mirrors). Another tiny mirror or lens moves rapidly back and forth to alternately create the first and second halves of the image and achieve 1,920x1,080 resolution. Wobulation can produce good results, and on some 1080p TVs, it can technically deliver all 1,920 lines of horizontal resolution; on other sets, it makes the image look softer.

One potential problem with DLP sets is known as the rainbow effect. Some people can see brief streaks of color on these TVs, especially in images with black fields and some bright features, such as a spaceship against a star field. This is caused by the fact that the single DLP chip uses a color wheel to create red, green, and blue, and hence all colors. The occurrence of these rainbows has been significantly reduced with the advent of newer, faster color wheels. Most people who watch a later-generation DLP never see rainbows at all, and the few who do usually only see them occasionally.

New DLP technologies address a few of these issues. Samsung sells HDTVs, such as the HL61A750 pictured above, that use LEDs instead of the traditional bulb. In addition to lasting 20,000 hours, the LEDs eliminate the rainbow effect. Mitsubishi, for its part, has developed a high-end, laser-powered DLP HDTV that hits the market later this year.

Next: See front-projection TVs

See other types of HDTV:
Direct-view (tube) TVs | Flat-panel plasma and LCD TVs | Rear-projection TVs | Front-projection TVs

Front-projection TVs

The The Samsung SP-A800B is one of the best performing projectors we've tested.

At the top of the screen-size ladder, you'll find displays that don't really qualify as TVs: front projectors. These light cannons can fill 100-inch screens, but they're not for everybody since they require a light-controlled environment and plenty of room. Plus, for optimal picture quality, you'll want to buy a dedicated screen, although you can use a white wall in a pinch. Screen makers such as Da-Lite and Stewart have special, low-gain screens designed to improve black-level performance.

CRTs are also used in front-projectors; think of those three-tube monstrosities that hang from the ceiling in the coach compartments of older airplanes. We won't discuss them here, however, namely because CRT projectors are quite expensive and are generally reserved for high-end, custom installations, where they put the local cineplex to shame.

DLP, LCD, and LCoS projectors, on the other hand, have become increasingly affordable. All three technologies project the kind of huge picture--from units as small as a shoebox--that you enjoy at the theater. They share many of the same characteristics as rear-projection mircodisplays, the most notable being a lamp that needs periodic replacement.

Technology type on front-projectors is less-important than it once was, because new advances have really leveled the playing field. LCD projectors can now produce deep black levels that compete well with DLP, for example, and the "rainbow effect" of DLP (see the rear-projection section) is also much less of a problem than it once was. Differences between front projectors today vary more widely by individual model than by technology type.

For that reason, we won't go into the details and differences between the three types of projectors here, except to say that they're mainly dictated by manufacturer. Sony and JVC are the main makers of LCoS projectors; Sony, Panasonic, Epson Mitsubishi and Sanyo are in the LCD camp (branded "3LCD," but it's the same thing) while Samsung, Optoma and BenQ are the main players in the DLP camp.

No matter which brand or technology you choose, one trend in front-projectors is undeniable: 1080p resolution is getting affordable. The least-expensive 1080p units are going for $2,500 and even less, and in general we recommend going 1080p on a huge screen. Front-projection is one of the few places where the difference in detail between 1080p and lower-resolution displays becomes clearly visible.

For the latest front-projector reviews, check out our best products list.

More HDTV coverage

See other types of HDTV:
Direct-view (tube) TVs | Flat-panel plasma and LCD TVs | Rear-projection TVs | Front-projection TVs