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Biography

Born: March 10, 1983 in Checotah, OK Genre: Country Years Active: '00s, '10s The first country singer to win American Idol, Carrie Underwood grew up in the small town of Checotah, Oklahoma, and began singing with her church at the tender age of three. Throughout her childhood, she also performed at functions for the Lion's Club and Old Settlers Day, eventually moving on to festival gigs in several states. Along with developing her singing, Underwood learned to play guitar and piano. She graduated from high school as her class salutatorian and majored...

Top Albums By Carrie Underwood

All-American G.. Just Stand Up!.. Just a Dream Cowboy Casanov..

Top Songs By Carrie Underwood
	Name	Album	Time	Price
1.	Good Girl	Good Girl - Single	3:24	$1.29
2.	All-American Girl	Carnival Ride	3:33	$0.99
3.	Cowboy Casanova	Play On	3:55	$1.29
4.	Before He Cheats	Some Hearts	3:19	$1.29
5.	Undo It	Play On	2:58	$1.29

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Picture and Viewing Features

The KDL-55HX820 series LCD from Sony is only a step down from the top of the line XBR-55HX929 which has full array local dimming for better backlight control for among other things – 3D TV programming enabling 1080p resolution to each eye (in effect). The 55HX820 forgoes the true local dimming in favor of less expensive LED edge lighting, but has all other top end features such as the new OptiContrast Panel Technology and the two-chip processing engine X-Reality Pro.
Of course 3D TV capability is there. During recent viewing with sources from 3D Net we noted some blurring during fast motion scenes on the HX920 series. We noted the same during some Cinema 3D and Sports 3D programming. Bright lights against a dark background are particularly alarming. That said the X-Reality PRO dual chip processing engine is fantastic at processing normal 2D signals – even fast motion. The TV has a fantastic picture quality with non-3D sources with incredibly deep black levels and eye-popping definition. Colors are rich but not oversaturated.
Unlike many of Sony's competitors 240HZ rate features, we actually like Sony's. On the HX820 series the feature is called XR 480Hz. While not as strong in terms of effectiveness, it doesnt introduce lots of nasty artificial effects. Sony the MotionFlow XR 480 (manipulated 240Hz) builds on previous efforts to neutralize judder caused by camera movement as LCD and LED TVs struggle to process these movements fast enough.

Appearance

The new monolithic design from last year is present on the new HX820 series. The edge lit LED LCD TV is only 1” in depth with a thin framing bezel.

Internet Applications and Connectivity

Sony was the first out with a true Internet TV this past fall of 2010 with the GT1 series, enabled with Googles Chrome browser. The HX820 does not have the Google TV application, but it does Sony's new Bravia Internet Video and Qriocity functionality which has among other premium Internet TV Apps HuluPlus, Pandora, Amazon VonD, You Tube, Slacker Internet Radio, Crackly, Hmm why am I not seeing Netflix here? Must be a typo in the specs from Sony. Does anyone dare not carry Netflix?
Qriocity also has a highly touted (by Sony) music options service – Music Unlimited powered by... you guessed it, Qriocity. Hey, I just want it free, I want to buy this TV and it enable me to get the music I want for free! Deal!

Standout Features

The KDL-55HX820 has nearly everything Sony has to offer this year in top features. Motionflow XR 480; a manipulated 240Hz rate which simulates 480Hz due to use of the edge lit LED backlighting.
Edge Lit LED backlighting, 3D TV ready.
The new X-Reality Pro Video Engine is a two chip processing engine rather than 1 used in the normal X-Reality engine. It is quite useful in that it upconverts and improves the picture from low resolution Internet content sources. It also optimizes high definition content, compressed HD signals, standard definition, and other sources. By utilizing a vast database of "ideal" signal patterns developed by analyzing and indexing and enormous library of film and video, the X-Reality PRO Engine compares incoming signals pixel-by-pixel with ideal scenes to display vivid and detailed images.
The embedded Skype features has increased resolution to 720p high definition to receive better images when video chatting.
A new Media Remote control application option for the iPhone, iTouch, or mobile Android devices. The app, which may be downloaded from the Apple App Store or the Android Marketplace, functions as a full remote with keyboard, allows online content search, and playback.

 

3D TV Technology Is Here!

With the advent of 3D TV now upon us everyone wants to know how it works. As most of us know the concept has been around for a while, but it is only now being incorporated into HD televisions.
Three dimensional televisions use a technology that employs stereoscopy to fool your eyes (actually your brain!) into believing that there is depth to the images that you are viewing. And of course this is just an illusion, but when you watch 3D TV what you see will look very real and just like what you see around you every day. Real images with real depth!

How Does It Work?

The reason that stereoscopy works is that it tricks your brain into thinking that there is real depth to the images your eyes are seeing and it does this by supplying each of your eyes with 1 of 2 slightly different images at the same time.
This increases your brains perception of depth in those images.
The main technique in making this work effectively is to ensure that the two image views that each eye sees is what each eye would see individually in real life, so that these two different perspectives of the same objects in the scene are what your eyes would see naturally due the distance that your eyes are apart on your face.
This sounds complicated but the theory is simple, however getting it to work on a television screen has been difficult until now.
In fact there are three different technologies available that have been used to produce 3D movies and the actually work in different ways and use different technology to get the three dimensional effects required.
The good news is that 3D TV really does work!

Active Shutter – Alternate Image 3D Technology

This the newest of the 3d technologies and this is what is fasting being adopted as the new standard for use in 3D TV technology and is therefore the one you will be watching on your 3D television or home cinema system at home. Alternate Image is an active system and is already available in high definition HD televisions sold by Samsung, Panasonic and LG in the UK.
This 3D technology requires a HD television to work as the slightly different image perspectives of the same scene being viewed are continuously displayed in turn for each of your eyes – first for your left eye, then for your right eye and then your left etc etc. This is also called auto frame sequencing (sometimes referred to as Alternate Image or AI).
On a technical note this means that effectively the frame rate for 3D TVs is halved (one eye at a time!), so you will find that the refresh rate on these televisions will be a minimum of 120 Hz (up from 60 Hz) and often they will be even higher than this at 240 or even 480 hz.
In order for you to see these scenes correctly in 3D your eyes need to only receive the intended image in turn for your left or right eye (as displayed on the TV screen).
Therefore as a viewer you will need to wear active “liquid crystal” shutter glasses to see these 3D effects.
These act as alternate shutters for each eye and block off the view to each eye in turn and in sequence with the scene images being displayed on the 3D TV screen.
Be assured though that very soon there will also by 3D TV systems available that will not need you to wear glasses to watch, so just hang on for a while if that is what you want.
The synchronization between the 3D TV and the active glasses is managed and controlled by a radio, Bluetooth or infrared system built into the television. This is currently the system that gives the best 3D effects on a television.

Polarization 3D Technology

This polarization technology, which is often referred to as a passive system, is what you will have seen if you have watched any 3D movies at an IMAX cinema or theater. Films such as the blockbuster Avatar in 3D is typical of how successful this system can be.
When watching movies developed for this passive system you will need to wear special polarized 3D glasses to see the 3D effects. Two slightly different perspectives of the same scene are projected onto the cinema screen through separate polarizing filters and illusions of tree dimensional images are created by a restriction of the light reaching each of your eyes through similar polarization filters in the glasses.
Although the glasses are cheap to produce the 3D images are not quite as good as those provided by the newer active technology, which seems to produce sharper images in three dimensions. These are battery powered (lasting 80 hours or so)

Anaglyphic 3D Technology

This was the first and therefore the most famous of the 3D technologies to be introduced and this use the red and blue paper glasses of early attempts, but to be honest the three dimensional effects of this earlier technology were not really that good. Unfortunately most of the Anaglyphic 3D movies you can get on DVD and more recently BluRay discs will be using this technology, so be aware of this when buying.

New 3D Technologies

The ability of HD TVs to provide a system that you can view in real 3D has only just begun so these technologies are really very new. As there is a great deal of interest in 3D TV and an obviously a large demand from consumers to buy these televisions, manufacturers and technologists are already busy discovering and inventing new ways of providing 3D systems for you to view.
One of the biggest drawbacks of the current system is that the viewer has to wear 3D glasses, therefore it is highly likely that there will soon be inventions and therefore systems that will enable you to watch 3D movies on TV without having to wear glasses for viewing.
When this will arrive only time will tell, but be assured that the current 3D TV active systems available on “three dimension” equipped HD televisions work very well!

Read Reviews For The Best Deals

As this technology is new the prices of 3D TVs is still relatively high when compared with HD televisions, but this will change over time as more manufactures provides 3D TVs and competition will ensure some cheap deals will start to come to the 3D marketplace. Getting a great deal is often what we are all looking for and even now it is possible to get some better deals.
The best thing for you to do as a consumer is to read customer reviews of the latest 3D TV models that they have already bought and used before you even thing about being ready to buy one for yourself. This way you will get to quite appreciate what is a good deal and what is not. What you buy needs to work as well as you want and also meet all your expectations. Owner reviews will tell you how these products perform and how they met the expectations of others and you can learn a lot from this.

I've written articles in the past explaining various TV technologies, including the differences between 720p and 1080p and 120Hz and 240Hz LCD TVs. But with Samsung, LG, Sony, and other manufacturers pushing so-called LED TVs these days, it's high time that I--with an assist from our resident video guru, David Katzmaier--sort through all the marketing mumbo jumbo and provide some insight into just what an LED TV is. Here goes.

1. An LED TV is not a new kind of TV.
I appreciate a good marketing ploy as much as the next guy, but an LED TV is just an LCD TV that's backlit with light-emitting diodes (LEDs) instead of standard cold-cathode fluorescent lights (or CCFLs). And though they became well-known last year with Samsung's ultrathin models, LED-backlit LCDs have been on mainstream store shelves since 2007, when Samsung's LN-T4681F debuted.
Unlike plasma and OLED, which are emissive technologies where each pixel is its own discrete light source, LCD is a transmissive technology where each pixel has to be illuminated from behind, or backlit.

2.There are two LED backlight configurations
 
Initially, LED-based displays like the Samung LN-T4681F were backlit by what's referred to as a "full array" of LEDs behind the LCD, across the back of the panel--just like a standard CCFL backlight. But to create even thinner TVs, engineers needed to eliminate that extra layer of LEDs and move it to the sides of the display. With this form of backlighting, the LEDs are affixed to all four sides of the TV and light is projected inward to the middle of the TV via "lightguides." These types of TVs are commonly referred to as "edge-lit" LED-based LCDs, and are by far the most common available today.



3. Each configuration may also offer "local dimming."
All current LED-based LCDs with rear-placed, full-array LED backlighting--except the Sharp LC-LE700UN series from 2009--feature a technology called "local dimming." With local dimming, portions of the backlight can be dimmed or brightened independently when different areas of the picture get darker or brighter. For example, the LEDs behind the words in a credit sequence can illuminate while the ones behind the black background remain dim.
Being able to dim portions of the screen helps reduce the amount of light that leaks through to darkened pixels, and the end result is blacks that appear darker and more realistic. Since black levels are crucial to contrast ratio, the deeper the blacks, the more the picture--and colors--appear to pop. Also, the image as a whole will seem crisper. A couple of examples of local dimming done right are Samsung's UNB8500 series and LG's LH8500 series--respectively the best and second-best LCDs we've ever tested.
One downside to local dimming is an effect called "blooming," where brighter areas bleed into darker ones and lighten adjacent black levels. This "blooming" effect varies widely from model to model; it's pretty noticeable on the Toshiba 46SV670U, for example, and much more difficult to notice on the Samsung and LG 8500 sets. Incidence of blooming is directly related to how many local-dimming LED elements ("dimmable zones") are behind the screen, but some manufacturers won't divulge that information.

With standard CCFL backlighting and most edge-lit LED backlighting, the entire backlight dims or brightens at once (aka "global dimming"), if at all. There are a few 2010 LED TVs from Samsung and LG, however, that can perform a semblance of local dimming from an edge-lit configuration. Samsung calls its technology "precision dimming" to help differentiate it from true local dimming, and it's found only on the high-end UNC8000 series. (Samsung has not announced a 2010 TV with full-array local dimming.) LG calls its version "LED Plus," and it's found on the LH5500 and LX6500 series. In our tests we liked Samsung's version better, but neither performed as well as true local dimming.
4. Edge-lit TVs are really thin, but uniformity suffers.
As I said, the key benefit to an edge-lit LED-backlighting scheme is that manufacturers can make thinner TVs. However, the downside is that the backlighting isn't quite as uniform. With edge-lit displays, if you put a white image up, you may notice that the outer edges of the screen appear brighter, or "hotter." Also, when you put up an all-black image, the edges of the screen will appear lighter (grayer).
5. LED backlighting of either variety doesn't improve LCD's poor off-angle viewing.
Unlike with plasma, one of the big downsides to LCD TVs is that the picture degrades if you're sitting off to the side or the TV is placed too high or low, based on your eye level. LED backlighting doesn't change any of this and, in some cases, may actually make things worse.
The Samsung 8500, for example, currently offers among the best black levels of any LCD we've seen--so long as you're sitting in the sweet spot, with the middle of the screen between your eyes. Move a few feet to the left or right and you'll notice that the picture doesn't look as good. Why is this so apparent? Well, the problem is that you're starting with such a good picture, so you're more apt to notice the difference when you move to the side or stand up and look down at the TV. With a TV picture that doesn't look as good to begin with, the difference doesn't look as stark when you move off axis. Make sense?
6. LED backlighting is even more efficient than standard fluorescent backlighting.
It's definitely true that LED backlighting can cut down on power use, and some LED-backlit LCDs are, inch for inch, the most efficient flat panels available. On the flip-side, standard fluorescent backlighting is getting more efficient itself.
Our survey of TVs we've reviewed since 2008 finds that LED TVs use, on average, about 101 watts, compared with 111 watts for standard LCD TVs. Of course, screen size and picture brightness can affect power use significantly, but even in the largest screen sizes LED saves only about $20 per year.
On the other hand, it's also worth noting that LCD TVs of both varieties continue to be significantly more energy efficient than plasma TVs. For example, Panasonic's 50-inch TC-P50G20 plasma costs $46.55 per year after calibration, whereas the 52-inch Sony KDL-52NX800 LED costs $20.96.

7. LED backlighting will get better--but how much better is debatable.

Though it's true that manufacturers' backlighting schemes will continue to improve with time, we've heard from industry insiders that the real advancements will be in edge-lit technology. Engineers are trying to improve edge-lit backlighting to the point that it equals or even surpasses full-array LED backlighting.
One of the issues with full-array backlighting (that features local dimming) is that to truly perfect it would require 2.1 million LEDs to individually light 2.1 million pixels (in a 1080p TV). Adding that many LEDs simply isn't cost efficient, and sources tell us that for the foreseeable future, engineers have maxed out the number of LEDs they can add to a panel without making the end product prohibitively expensive.

8. LED equals higher price tag.
 
While we're on the topic of expensive...as you're probably aware, LED-powered LCD TVs cost more than non-LED models. The profusion of LED models in 2010 has improved selection, especially among smaller screen sizes, but the cost premium for LED is typically at least $400.
LG's least-expensive 32-inch LED, for example, is the 32LE5400 ($1100 at Best Buy currently), whereas the company's most-expensive non-LED at that size is the 32LD550 ($700). Sony's KDL-46EX600 (LED: $1,350) and KDL-46EX500 (non-LED: $990) provide another example at 46 inches, as do Samsung's UN46C5000 (LED: $1,350) and LN46C550 ($950). In 2010 LED is priced as the major step-up feature of LCD TVs.
On the other hand, with the entry of brands like Vizio and even Westinghouse into the LED TV market, we expect competition to intensify and prices to fall quickly over the next year. The excellent Vizio VF551XVT ($1,400) is a 55-incher that costs hundreds less than similar models from traditional brands.

9. Top LED TVs can come close to the picture quality of the best plasmas, but they still have drawbacks.
 
LCD TVs have long been knocked for not producing the deep blacks of plasma TVs. Well, with the introduction of LED backlighting with local dimming, blacks on the best LED TVs can go toe-to-toe with the blacks on some of the best plasmas, and the picture is outstanding. Also, as noted, LED-backlit LCD TVs are more energy efficient than plasmas and weigh less. But off-angle viewing and picture uniformity remain a sticking point. With plasma, by comparison, you can sit to the side of the TV and the picture won't degrade, and blooming and other uniformity problems are nonexistent.
On the other hand, we haven't seen any major picture quality benefits to edge-lit LED technology--with or without dimming. In some cases, LED TVs have worse picture quality than their standard CCFL-backlit cousins. As usual, performance varies widely from model to model, but don't expect LED to automatically equate to a better picture.

10. If you don't have your picture settings correct, LED or non-LED won't make a difference.
You can have the best HDTV in the world with the latest and greatest technology, but if it's not set up correctly, it can look pretty run of the mill. Luckily, with every TV David Katzmaier reviews here at CNET, he posts his optimal settings in the HDTV picture settings forum.

Samsung PN64D7000 Review

Model: Samsung PN64D7000
Description: Full HD 1080p 64" Plasma TV 3D TV Compatible
Reviewer: Robert Wiley
Date: Summer 2011
In 2011 one of Samsung's theme for plasmas is "+1", by making the bezel even thinner they are adding 1 diagonal inch to every size of plasma, 51 replaces 50, 64 replaces 63 and so on. With the smaller bezel the physical size of the TV remains the same even though the screen is larger.

Strengths

• Realistic vibrant coloration
• Black levels and Dark Shadow detail
• Great Film Like experience
• Wireless In Built
• Smart Hub Internet Suite
• Design and Appearance
• Value Pricing
• 3D Viewing Quality/Depth

Weaknesses

• Peak light output/ Brightness
• No Access to menu/picture settings with Smart Hub
• Back metal plate gets hot during operation

Picture Quality Rating (HD): 9/10

We thoroughly enjoyed reviewing the C7000 plasma series last year and we know that these TVs can deliver a great picture quality. The D7000 series also renders a superb picture, but slightly different than what we saw last year. First, let's start with the Picture Mode options which are fairly limited compared to many TVs we review. Preset Modes are Dynamic, Standard, Movie, and Relax. The Relax and Movie modes are pretty solid right out the box. We ISF calibrated the picture from the Movie Mode to D6500K and post those picture settings on the next page. We then measured peak brightness and peak black to determine a range of contrast and this is where we were first surprised. Contrast measures about half on the D7000 series than it did last year. We found the reason for the decrease to be less light output (brightness) rather than black performance. We attribute this decrease to one or both of the following explanations: 1) Plasma panel Image retention (not burn in) issues could have influenced Samsung to decrease light output and/or 2) Samsung had to reduce light output to meet internal or external energy consumption reduction requirements.
For 3D the PN59D7000 uses active shutter glasses and is Full HD 3D, sending 1080 lines of vertical resolution to each eye. Some televisions sacrifice some resolution to show 3D images and Full 3D HD provides the best 3D experience.

Picture Quality Rating (Non-HD): 9/10

Features Rating: 9.5/10

3D TV Viewing: 3D viewing is much improved from last year. The PN51D7000 is full HD active shutter 3D and comes with Samsung's 3D starter kit which includes 2 pairs of active shutter 3D glasses model SSD-3100GB and a Shrek 3D movie. The TV recognizes when the 3D glasses are synced and an alert pops up on the screen stating, "3D Glasses are now connected." Many of the issues we noted last year are gone. There was no blurring in the bottom left and right corners of the screen. There was no crosstalk and flashing from the glasses from ambient room light. Images looked great and the depth is excellent depending on the 3D movie. The PND7000 3D plasma technology does justice to 3D technology. It certainly involves you in the picture. We did note some eye fatigue after viewing for a while but not as much as last year.
Design and Appearance: The Samsung PN51D7000 looks much the same as the PND8000 series from last year except with a thinner framing bezel. It's a great looking set. The thin 1" brushed charcoal metallic finish lends a very expensive look and the depth of the TV is the same at just 1.4". There is a thick glass edging all the way around the TV. The screen when off is a deep rich charcoal color. The TV comes with a solidly built heavy table top which swivels 21 degrees side to side. Lastly, the neck is a clear acrylic piece that makes the TV look as if it's floating in air.
Inputs: Though there are 4 HDMI, 2 USB, a PC input, there is only one shared input for component and composite through an included breakout cable. Inputs are located within a cavity and pointing out the side of the TV to allow for tight wall mounting.

Value Rating: 9.5/10

The PN64D7000 has a lot of features and fantastic picture quality packed into an excellent, classy looking TV. 3D glasses are not included in the box, so those will have to be purchased separately. Many dealers are selling a bundle package with a 3D starter kit that includes 2 pairs of glasses and a 3D movie at a slightly higher price but purchasing that way will save you some money on the glasses. Competition comes from the Panasonic TC-P65GT30 and the slightly smaller LG 60PZ950.

1. What is 3D TV?
3D TV is a generic term for a display technology that lets home viewers experience TV programs, movies, games, and other video content in a stereoscopic effect. It adds the illusion of a third dimension, depth, to current TV and HDTV display technology, which is typically limited to only height and width ("2D").

2. How does 3D TV work?
A 3D TV works much like 3D at the theater. A screen showing 3D content displays two separate images of the same scene simultaneously, one intended for the viewer's right eye and one for the left eye. The two full-size images occupy the entire screen and appear intermixed with one another--objects in one image are often repeated or skewed slightly to the left (or right) of corresponding objects in the other--when viewed without the aid of special 3D glasses. When viewers don the glasses, they perceive these two images as a single 3D image, a process known as "fusing."

The system relies on a phenomenon of visual perception called stereopsis. The eyes of an adult human lie about 2.5 inches apart, which lets each eye see objects from slightly different angles. The two images on a 3D TV screen present objects from two slightly different angles as well, and when those images combine in the viewer's mind with the aid of the glasses, the illusion of depth is created.
3. How is the new 3D TV technology different from older 3D?
Most people are familiar with the old anaglyph method, where a pair of glasses with lenses tinted red and cyan (or other colors) is used to combine two false-color images. The result seen by the viewer is discolored and usually lower-resolution than the new method.
The principal improvements afforded by new 3D TV technologies are full color and high resolution--full 1080p HD resolution for both eyes in Blu-ray 3D, for example, and half that resolution in broadcast 3D used by DirecTV and other providers. Note that current passive 3D TV technology affects adversely resolution (see #5).

(Note: For the remainder of this article, any mention of "3D" refers to the new full-color version, not the old anaglyph variety.) 4. How is 3D TV different from 3D in the theater?
Many viewers have experienced newer 3D presentations, such as IMAX 3D, in movie theaters. Though the technologies can differ somewhat--most U.S. theaters use passive glasses, for example (see #5)--the main practical differences between 3D TV in the home and theatrical 3D are the size of the screen and the distance you sit from it.
In the home the image is generally much smaller, occupying a lower percentage of viewers' fields of vision, so it's generally less immersive. With 2D you could create a more immersive home theater by sitting closer to the screen, but with 3D that can become a problem. Panasonic recommends a seating distance of no closer than 3x the screen height away--about 6.2 feet from a 50-inch screen--and cautions that sitting closer could increase the risk of eye fatigue and headaches. One expert we talked to, Martin Banks of UC Berkeley, confirmed that sitting too close to a 3D screen can heighten the risk of such adverse effects (see #7).
Smaller screens may also present other issues unique to 3D, such as a relatively narrow viewing distance range. We've also seen that the edge of the image, which is much more noticeable with smaller screens, can disrupt 3D viewing much more disconcertingly than 2D.
One advantage of 3D TV at home as opposed to the theater is user control. Some 3D compatible TVs provide control over the 3D experience in addition to standard picture settings. Samsung's models, for example, allow you to adjust the "G axis," or the amount of 3D effect, to taste, comfort or to compensate for variations in eye spacing.
5. What's the difference between active and passive 3D?
Most 3D TVs use active liquid crystal shutter glasses, which work by very quickly blocking each eye in sequence (typically 120 times per second) to separate the different right and left images required for 3D. The glasses, in addition to the liquid-crystal lenses, contain electronics and batteries (good for 80 or more hours and often rechargeable) that sync to the TV via an infrared or (in many 2011 models) RF signal. They currently cost $60-$120 per pair when sold separately.
In 2011 Vizio, LG and Toshiba will introduce 3D TVs that use passive polarized 3D glasses that are much less expensive. They are actually compatible with the passive 3D used in theaters, and will work with Real D's circular polarized glasses, for example, which are available for as little as $5 each online. The 2011 models use a technology called Film Pattern Retarder, developed by LG, where a polarizing film coating the TV screen allows each eye to view every other line. See #31 for our impressions.
At CES 2011 Samsung and Real D announced RDZ, a system that claims to deliver full resolution yet allow the use of cheaper passive glasses. Products with this or similar technology won't be widely available in 2011, however.

  The principles behind 3-D HDTVs explained
We all know that a television, any television, displays 2 dimensional images so how does a 3D TV create the illusion of 3 dimensions? Read on to find out.

Creating the illusion of 3 dimensions relies entirely on the fact that we have two eyes separated by a particular distance. If each eye is shown the same image shot from slightly different angles then when your brain combines the image it will appear three dimensional. This is the principle that all 3D effects use, from your old red viewmaster to Avatar shown at IMAX. The viewmaster showed a completely separate image image to each eye, 3D movies and television rely on two different methods.
In the first the two images needed to create the effect are combined into one image. Each image can be altered by a color filter or a polarized filter. With the color filter the viewer will wear 3D glasses with two different colored lenses, the glasses then block out one of the two combined images so each eye sees a different angle of the same shot producing a 3D effect. Orginially this method, called Anaglyph, required 3D to be created without a color picture but modern advances have allowed 3D to be done in color with this method although color quality still suffers. Polarization uses the same princliple but rather than altering the color of an image it alters the waves of light the viewer sees. The glasses the viewer wears have differently polarized lenses which only show one image to each eye, picture quality is better with this method and it is what is used in most 3D movie theaters.

The second method involves powered 3D glasses that have LCD screens for lenses. The glasses are synced to the display via infrared or another method and the two different angles of each frame are shown sequentially to the viewer. The lenses alternately open and shut so each eye sees a complete version of each angle rather than parts of a combined version. This actually works similarly to the old viewmaster mentioned above but rather than showing each eye a different image at the same time, the images are seen in rapid sequence. This is a very effective method of creating the 3D effect but it halves the frame rate of the content. Video normally runs at 30 frames per second (29.97 to be exact) so with this method of 3D each eye is only seeing 15 frames per second, this lessens the apparent smoothness of the content.
Another method of 3D, without glasses, has been around for a few years but it is just now starting to come to market. This method uses filters or lenses in front of the screen to direct the separate images to each eye. Early versions of this technology required the viewer to maintain a very specific distance and position in relation to screen, even relatively minor deviations would break the 3D effect. Today combining the filters and/or lenses with a camera and face recognition software creates the ability to just the screen in real time to project to the split images to the current location of the viewer's eyes. Nintendo is using the version of this technology that requires your head to remain in a fixed area on their 3DS handheld and Microsoft has even created a screen that uses face recognition that can project 3D to 4 people in real time.

Even though 3D viewing has been around for more than century in one form or another is really is still in it's infancy. Expect more 3D breakthroughs in the years to come as it's popularity is on the rise again.