3-D TV Buying Guide

So is 3-D TV just an empty fad or a worthwhile investment? She makes those glasses look good, but as you'll soon read, the glasses -- and the TVs -- have a ways to go before they're perfected.
Image courtesy LG Electronics

From huge, clunky cathode ray tube boxes to sleek, lightweight, high-definition marvels, our television sets have evolved in colorful, picturesque ways. In spite of these transformations, most TVs are similar in that they display only two-dimensional images. But these days, engineers and manufacturers are hard at work adding a third dimension that promises to change the image quality and power of TV images forever.

There's a reason companies are pushing 3-D, and the reasons are right there in front of your eyes. Although TV screens have two dimensions (height and width), they lack depth. But the human visual experience includes depth, too, and that last element is critical.



Close or cover one of your eyes and try to perform some of your daily activities and you'll quickly realize that without two eyes, you have very little depth perception. Depth is exactly what's missing from your television experience.

Imagine how a crisp, clear 3-D image from your television would affect your entertainment. Those action and horror movies would have scenes that wallop your retinas with amazingly lifelike effects. On game day, leaping wide receivers would seem as if they're about to land on your coffee table. In short, 3-D technology would be more dramatic, more realistic and, quite possibly, more fun than plain 2-D TV.

Believe it or not, that depth may come sooner than you thought. Yet this technology is still in its infancy; as with many evolving tech toys, there are few established standards for 3-D TVs, but for one -- these models are always priced higher than their 2-D brethren. That means you'll undoubtedly spend a lot of money to get one, and if you don't think carefully before you drop all that cash, you could very well wind up with a product that makes you wish you'd stuck with a more archaic 2-D version.

Fear not, we'll guide you through the basics of 3-D TV tech and point you toward the kind of technology that will give you the best and most realistic bang for your very much 3-D money. Keep reading and you'll see all about how the TV age is entering its new dimension.

Toshiba's TL515U uses passive 3-D technology, and it comes in sizes ranging from 32 to 55 inches (81 to 140 centimeters).
Toshiba's TL515U uses passive 3-D technology, and it comes in sizes ranging from 32 to 55 inches (81 to 140 centimeters).
Image courtesy Toshiba

Your two eyes, spaced roughly 2 to 3 inches (about 6 centimeters) apart, give you stereoscopic vision. Each eye sees a slightly different perspective than the other. Your brain fuses the two points of view, providing depth to the scenes you see.

Old-school video is recorded with a single camera, giving a depthless, 2-D look to images on a typical 2-D screen. But live-action 3-D movies use multiple cameras to record their subjects. And 3-D games use sophisticated computer modeling to create more than one perspective. From there, it's just a matter of relaying that 3-D image to your eyes.



At many early 3-D movies, the audience wore funky glasses with one red lens and one cyan lens. These films used the anaglyph technique, in which images had two different color layers; one reddish and one bluish. Thee glasses meant each eye perceived only parts of the film tinted a certain color, and the result was a rough 3-D image.

Most contemporary 3-D moviegoers wear polarized glasses. The film is shown with two projectors at a slightly different angle, and the glasses ensure that each eye sees only the image meant for it. Again, your brain combines the images and is tricked into thinking you're seeing 3-D objects.

Projectors simplify the 3-D process in a theater because it's easy to set up and synchronize video beamed onto a screen. But in engineering terms, this feat is quite different -- and quite difficult -- to pull off in a home TV. With LCD and plasma HDTVs, there is no projector. You'll read more about how manufacturers create 3-D at home on the next page.

For now, though, keep in mind that you need more than a 3-D TV to have an eyeball-exploding 3-D experience in your home theater. Perhaps most important -- you need access to 3-D content. The vast majority of TV programs are 2-D, with the exception of extra special sporting events (such as World Cup soccer) and the like. This is simply because for every show that airs in 3-D, the producers must also provide 2-D HD content, a fact that ultimately can double production costs.

Games and movies created in 3-D are slowly becoming more common; you can a list of 3-D Blu-ray movies here. Still, you need a device that sends that 3-D content to your TV, and to that end you might use a 3-D Blu-ray DVD player or 3-D compatible gaming system; an older, basic Blu-ray player won't cut it. Sony's PlayStation 3 is one system that not only plays 3-D Blu-ray content but also 3-D games.

Happily, all 3-D TVs are backward compatible with 2-D broadcasts and content, and as 2-D images go, these models produce some of the crispest and most colorful images you'll see on a TV screen. Keep reading and you'll see a lot more about just how these TVs attempt to astound your eyeballs.

Glasses are necessary for both passive and active 3-D TVs. Sophisticated active shutter glasses like these are sometimes more effective and always more expensive.
Glasses are necessary for both passive and active 3-D TVs. Sophisticated active shutter glasses like these are sometimes more effective and always more expensive.
Image courtesy Samsung USA

Newfangled 3-D TVs take a slightly different tack toward their ultimate goal, which is to create two separated images, one for each eye. As such, there's no agreed upon standard for conjuring the illusion of a 3-D image on a home television. So TV manufacturers continue to experiment with a variety of established techniques, as well as those that are more unusual, and perhaps, unpractical.

Some home LCD or plasma TVs use a version of the movie theater system based on polarization. Unlike at your downtown theater, there's no projector involved.



Instead, the 3-D TV shows two slightly different images right out of the screen using a system of small lenses. Your polarized glasses make sure each eye sees only one perspective. Your brain does the work of blending things into an understandable 3-D image. This is what's called passive 3-D. Tilting your head backward, forward or to one side can interfere with the polarization process, though. Sitting at an angle to the TV can cause the same issue.

Active 3-D tech is different. In this system, the 3-D TV quickly alternates images intended for your right and left eyes. You wear active shutter glasses synchronized with the TV; these glasses have integrated LCD screens that rapidly flip from opaque to clear (at about 120 times per second), so that each eye sees only the images meant for it. That's why this technology is also called alternate-frame sequencing.

This rapid-fire shuttering system happens so fast that most people don't detect any flickering. The result? A crisp, high-definition 3-D image. As with passive systems, viewing at an angle can reduce 3-D effects, but active TVs have a reputation for outperforming passive TVs in this regard.

Many TVs require expensive, proprietary active shutter glasses that work with only one brand of television. However, manufacturers are considering a standard type of infrared or radio signal synchronization that will be compatible across brands. But regardless of the standard, the glasses are costly; you might pay around $100 for a single pair.

The glasses are battery powered. Some are rechargeable, while with others you can just replace the batteries when they die. Either way, the glasses tend to be a bit on the clunky side and more than a little bit dorky looking, two reasons that manufacturers are racing to create 3-D TVs that do not require glasses of any kind (more on that later).

Regardless of the technology, all 3-D TVs currently share the challenge of crosstalk, which is when one eye partially sees the image intended for the other eye. The result is a blurry ghosting appearance around onscreen objects that is distracting, can cause headaches and, in some cases, makes the program unwatchable.

There's no consensus on whether active or passive 3-D technology is superior. These TVs are just now advancing beyond their first generation, and no company has perfected its version. However, there's little doubt that the holy grail of 3-D TV tech is glasses-free 3-D. On the next page, you'll see how this technique hopes to give you 3-D thrills without the headaches or fashion faux pas.

Those lame glasses that bring your TV's 3-D magic to life aren't so magical; in one survey, about 30 percent of respondents said the glasses were a turn-off for viewers [source: Physorg]. The glasses are unwieldy and breakable, and you might feel downright silly sitting in your living room plastering your face with these spectacles. That's why the idea of glasses-less 3-D TVs is so appealing.

They do exist. They rely on autostereoscopy to produce 3-D images, which is why this technology is sometimes called auto 3-D. There are a couple of technologies in the auto 3-D arena: parallax barrier and lenticular.



In a parallax barrier TV, images are split into alternating vertical columns, and each column is intended for either your right or left eye. Lenses bend the appropriate column toward the correct eye. Your eyes feed all of this visual input to your brain, which helps you perceive what looks like a 3-D picture.

With lenticular technology, tiny plastic lenses (called lenticles) are affixed to a transparent sheet that goes on top of the TV screen. These lenses magnify a portion of the image directly below it, and direct light from the picture at different angles toward your eyes. Each eye picks up a slightly different perspective, and your brain combines the images to complete the 3-D image.

Lenticular and parallax barrier TVs use similar principles to work their magic. They also have the same drawback, which is a very limited sweet spot, the area directly in front of the TV where the 3-D effect is most crisp and pronounced. Manufacturers are working hard to increase the size of the sweet spot so that people will be able to see vivid 3-D images, no matter which angle they're viewing from.

For now, though, auto 3-D TVs are extremely expensive and don't provide the kind of 3-D effects that active shutter and passive TVs create. In a few years, though, this technology may catch up and leave 3-D audiences blissfully glasses-free.

When you see a 3-D-ready label, it just means that a TV is 3-D compatible. It will come loaded with all of the input and output ports that allow it to connect to a range of 3-D-capable devices.
When you see a 3-D-ready label, it just means that a TV is 3-D compatible. It will come loaded with all of the input and output ports that allow it to connect to a range of 3-D-capable devices.
Image courtesy Samsung USA

As with all new technologies, 3-D TV specifications and feature lists come loaded with their own lexicon. One of the first phrases you'll hear refers to the TV being "3-D-ready."

Happily, there's nothing complicated about that terminology. It's just fancy marketing lingo that indicates the TV has 3-D capabilities. That's it.



In terms of specifications, some general rules apply to 3-D-ready TVs. Perhaps most important, these TVs -- whether they are LCD or plasma -- have a fast refresh rate, at a minimum of 120 hertz. Refresh rate refers to how fast the TV draws the picture on the screen. A faster rate means there's less chance you'll detect any potentially aggravating flickering, and it makes the 3-D images seem sharper, too.

It also means that the TV has an HDMI port that lets you feed high-definition 3-D to the TV. To achieve full-resolution HD for both of our eyes, the TV needs to adhere to at least the HDMI 1.4 standard. An HDMI port is the input port used for high-definition video, and it connects the TV to, for instance, a 3-D Blu-ray player.

A 3-D-ready sticker also means the TV will be able to handle various 3-D standards. For example, the unit will not only be able to display your awe-inspiring Blu-ray 3-D movies, but also varying resolutions of 3-D programs from other sources. Still, manufacturers take a small and extremely calculated risk by saying a TV is 3-D-ready, because there is no standard format for 3-D content.

There is a possibility that a 2011 3-D TV may not be able to correctly display 3-D formats that emerge a year or two down the road. That fact would infuriate consumers who paid top dollar for a "3-D-ready" TV that doesn't work with the latest and greatest content.

That's something to keep in mind as you shop for your 3-D TV. We'll cover more buying tips next.

Can your eyeballs handle 3-D images? If you're part of the 10 percent that can't, a 3-D TV probably isn't for you.
Can your eyeballs handle 3-D images? If you're part of the 10 percent that can't, a 3-D TV probably isn't for you.
artpartner-images/Photographer's Choice/Getty Images

If you're considering a 3-D TV, there are a range of topics to consider before you buy. Start by checking 3-D units at a local store to peruse image quality -- and to make sure you can see 3-D effects.

You read that right. Start by ensuring your eyes will tolerate 3-D images. Roughly 10 percent of people are unable to correctly see 3-D images [source: Eye Care Trust]. What's more, many more people experience headaches, nausea or discomfort when watching 3-D content, generally because of crosstalk or flickering. If you're one of these people, you may wind up using 3-D sparingly, or not at all.



Also, be leery of the hype. In spite of the massive marketing push, only about 2 percent of American households own a 3-D TV [source: Pipeline Pub]. Many people don't like the skimpy selection of 3-D content, or they recently invested in a nice HDTV and aren't ready to splurge again.

But if you're ready for the leap to a 3-D landscape, start by thinking big. The borders of 3-D TVs wreak havoc with the illusion of image depth. What's more, if the illuminated screen is too small, the dark background behind your TV may increase the likelihood that you notice the flickering of active shutter glasses.

Current 3-D technology offers the most impressive effects when it is displayed on a large screen. That's why manufacturers generally only offer 3-D on TVs 40 inches (more than 100 centimeters) and larger.

You may also wonder if you should buy an LCD or plasma TV. Manufacturers are still tweaking all 3-D related technologies so much, and so quickly, that there's no clear advantage to choosing between LCD or plasma for the long run. However, reviewers seem to prefer current versions of plasma units because they have less noticeable crosstalk than LCD. But no one is ruling out the possibility that newer LCD can't match or outperform plasma.

Likewise, you may have trouble deciding between active and passive TV. This decision will likely be even tougher than choosing from plasma or LCD. Neither technology has a clear leg up on the other. But if you have a large number of viewers and a small budget, the extremely affordable glasses used in passive systems will make a lot more sense.

No matter which TV you consider, you'll run into salespeople who tout simulated 3-D, a feature that makes even 2-D content look 3-D-ish. Don't expect this simulated mode to offer much more than a blinding headache. With all things 3-D, content is paramount. If the content isn't originally 3-D, it won't look so great, no matter how nice the TV.

Because 3-D technology is evolving so quickly, do your homework before you buy. Research in-depth product reviews from several sources, such as Consumer Reports, CNET and other tech-centric publications to make sure the model you want is worth the money.

With that bit of effort, you'll find the right TV. And before you know it, your TV watching will take on depth and dimension you may never have dreamed possible, right in your living room.


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More Great Links


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