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How Do 3D TVs Work?

How Do 3D TVs Work?

3D technology has come with a bang, and 3D devices are storming into the electronics market. Be it laptops, computers, or TVs, every consumer product has a 3D counterpart. All of us are familiar with 3D films, but have you ever wondered how do 3D TVs work? Let's find out.
Bindu swetha
Did You Know?
You are gonna love the latest product from Samsung that was demoed in CES 2013. This new OLED sends different images to different viewers in 3D. This means, you may watch your reality show, while your partner watches his favorite league match!

When James Cameron released Avatar, little did he know that the movie would have such a huge impact on 3D technology. It is not that we weren't introduced to this technology earlier, but the film only added to its popularity. 3D technology has now made its way into our households from the movie theaters. This technology has now reached the consumer market and is making its mark in the television market.

Today, along with the regular LCD, LED, and HD TVs, there are 3D TVs as well. These 3D TVs, that need glasses for viewing, are becoming extremely popular. These days, some of the latest 3D TVs have ditched these glasses, and use the screen to create depth in images. Regardless of the television you buy, i.e., 3D LCD or 3D plasma, the basic working of a 3D TV remains the same. Let's get acquainted with the working of a 3D television in this Techspirited article.

The Brain is Tricked
As we all know, the brain receives a signal (images) from both eyes. Then, it fuses these two images into one, and that is how we are able to see these images. The images we see are a byproduct of the post-processing by our brain. In case of a 3D TV, this post-processing is tricked. The images, that are seen by both eyes, have a time lag. So, when the two images are fused into one by the brain, a 3D effect is created. This is the basis of working of the 3D television.

How Do Passive 3D TVs Work?
Passive 3D uses the technique of polarization. The time lag between the images is created by the vertical and horizontal polarization technique. The glasses that are used for viewing passive 3D TVs are polarized. Each image is polarized in a different direction, and when these two parts of the same image are superimposed upon each other, a 3D image is created. The lens contains filters that block light, which is polarized in a different direction. Each eye sees a different image, which when fused together, forms a 3D image.

When you wear polarized glasses, the left eye lens is polarized by blocking the right eye view, while the right eye lens is polarized by blocking the left eye view. The left lens, if vertically polarized, will only see the vertically polarized part of the corresponding image, omitting the other part. Similarly, the right lens, which is horizontally polarized will see the horizontally polarized part of the corresponding image. When the two vertically and horizontally polarized images are superimposed, a 3D image is formed.

There are two types of polarization techniques that are used: linear and circular. In circular polarization, you can experience better viewing angles. This means that you can tilt your head a bit, and the 3D image will be still visible to you without any distortion. However, in case of linear polarization, the effect is reduced after tilting your head in a certain degree.

The passive 3D glasses are cheap and lightweight. This means that even if you are not able to get passive glasses along with your television set, you can afford to buy them. These glasses are not battery-powered. These glasses are the ones we receive in movie theaters to watch movies.

How Do Active 3D TVs Work?
Active 3D television explores the closing and opening of the shutter for creating 3D images. The screen displays images that are intended for the left and right eye. But, the switching speeds of these images is so high that it is barely noticed by the naked eye. These images are captured by the shutter glasses (used to view active 3D images) and then combined to form a 3D image.

Active shutter glasses have lenses that turn opaque or transparent when needed. It goes like this: The television set is the transmitter in this case. The signals from the television set are received by a small receiver that is present in these glasses. These signals are then read, and accordingly, the respective shutter glass will open or close. So, when the TV is transmitting an image for the left eye, the left eye's shutter will receive the wireless signal, and it will open, while the right eye's shutter will be closed as it doesn't receive any signal. After this, the TV will refresh itself, and the image intended for the right eye will be displayed. This time around, the right eye's shutter will open, and it will capture the image, while the left eye's shutter remains closed.

The opening and closing of the shutter doesn't literally mean that the left eye's glass will be open while the right eye's glass will be closed. Liquid crystal technology is behind it. When the right eye receives the signal from the television, the glass will turn transparent, thus capturing the image. During this time, the right eye's glass will turn opaque, which means that it will reject the light that falls on it. This opening and closing of the shutter glasses happens at such a fast rate that it is not visible to the human eye.

Active 3D glasses are heavier than the passive ones. This makes them difficult to use. Also, they need batteries to power them, which can be an additional task. Despite all these drawbacks, manufacturers today intend to use active 3D technology more than passive 3D, due to its better image quality. The image quality is enhanced because each eye can view the image in full 1080p resolution.

How Do 3D TVs Work Without Glasses?
The newest entrant in the 3D arena is the glasses-free television. This technology is also known as parallax barrier technology. This means that we can watch 3D content on our television screens without having the need to wear 3D glasses. For this, a barrier is created in front of the screen, which does the trick of creating 3D images and projecting the same.

The screen, as usual, shows both left and right images. From these images, certain light patterns are separated from each other, and these different light patterns reach the eyes. This differentiation in the light pattern creates 3D images. The screen has slits through which a specific light pattern passes. If you are seated right across the correct barrier, you will be able to see the 3D effect.

You need to be seated in a particular place to be able to view this three-dimensional effect. However, Toshiba has come up with a new technology known as multi-parallax technology. This technology promises to increase viewing angles, thus enhancing the user experience. As of now, it is still in the developmental stages.

All the three technologies mentioned above have their share of pros and cons. However, it is up to the user to choose the correct 3D television. Always look at your comfort and need before buying a TV.