Everything you need to know about 3D TVs

If back in 2010 it was quite difficult to buy a TV with 3D support, because such devices were classified as expensive and advanced, today even models of the middle price range can boast of this. In addition, users have the opportunity to shoot 3D video on their own, using specialized video cameras, 3D cameras or even smartphones.

The term "three-dimensional image" in this context is not entirely correct, since it only implies the creation of the illusion of three-dimensionality. The terms "3D" or "three-dimensional" just caught on because of their simplicity, because they are easier to remember and pronounce than "stereoscopic image" or "stereoscopic cinema". The general principle of creating such films is simple. When shooting, two cameras are used, which results in two images, each of which is intended for one eye. Further, the human brain is included in the matter, which, “gluing” the picture into a single whole, receives the illusion of volume. Note that the illusion will immediately disappear if one eye is closed while viewing.

What is 3D: two images are displayed on the TV screen at the same time, and special glasses allow you to separate them so that one eye sees its own, and the other — its image

As we know, when watching 3D movies, one cannot do without special glasses, thanks to which the image is separated for each of the eyes. There are two types of glasses: passive and active. Accordingly, 3D is called active and passive.

TVs with passive 3D technology

Passive polarized lenses do not miss half the lines

TVs with passive 3D glasses are anaglyph and polarized. Anaglyphs use two colour filters to create volume — red and blue. The simplest version of anaglyph glasses is a piece of cardboard with two pieces of coloured film glued on, you can even make them yourself. The advantage lies only in the extreme cheapness and the absence of the need for special equipment. But they are not able to provide good quality and noticeably distort colours. Modern equipment practically does not use anaglyph glasses, so further, speaking of passive 3D, we will only mean polarizing technology.

Polarized glasses are also divided into subtypes, but the principle of operation is similar for all of them. Each of the glasses has its own polarization and passes only “its own picture”, while two polarized images are projected on the screen at once. These glasses are more expensive, but the difference is not so significant. On the one hand, they are easy to use and do not distort colours, which is a plus. On the other hand, polarized lenses do not let through half the lines, that is, the image is obtained with a resolution of not 1920x1080, but 1920x540 pixels. So, if you sit close to the screen, you will see something like a grid in the form of black lines, as seen in the photo on the right. In an attempt to eliminate this drawback, manufacturers more or less successfully use various proprietary technologies.

What is active 3D?

As for TVs with active 3D, their glasses are already a whole device with its own electronics and power source. Today, shutter glasses are ubiquitous. They have special glasses based on liquid crystals, which alternately close the left and right eyes at high speed. Images on the screen are also formed alternately, so all screens with support for active 3D have a double frequency — 120 Hz versus 60 Hz. Otherwise, viewing would be a very uncomfortable procedure. The glasses themselves are synchronized with the equipment using a wire, an infrared signal or a Bluetooth interface.

The advantage of technology lies in high quality. The user sees the image at the resolution of the source, the number of lines is not reduced, and the viewing angles are wider. However, shutter glasses are more expensive (sometimes over $100) and more technically difficult. They need an additional power source or an inconvenient wire. And it will be extremely unpleasant if the battery suddenly runs out while watching.

Left: Passive 3D through glasses. Middle: passive 3D without glasses. Right: Active 3D

The frequency of 120 Hz on a TV can sometimes be insufficient when watching dynamic scenes, and more “high-speed” models are noticeably more expensive. Also, shutter technology requires high brightness from the image. In the case of a TV, this is not a problem, but for 3D projectors it can be unpleasant. But the main problem is more strain on the eyes, which leads to headaches, dizziness or even nausea.

As you can see, both passive and active 3D have advantages and disadvantages. And it cannot be said that one type has an undeniable advantage over the other, whatever manufacturers say in commercials.

What to look for when buying 3D equipment

Image Quality Comparison of Active and Passive 3D

Today on the market you can find TVs with active and passive 3D. It all depends on the manufacturer. For example, Samsung and Sony prefer active technology, while LG Electronics prefers passive technology. Philips produces models with both.

Ideally, before buying, you should try out the model you like in action. But, unfortunately, this is not always possible. Fortunately, it's easy enough to compare technologies by watching movies on both.

Thus, active 3D seems to be technologically more advanced and promises better quality. But on the Web you can find a lot of reviews from people who complain of severe headaches and eye fatigue after 15 minutes of viewing. Some even claim that they are able to see the switching of glasses glasses, which still raises reasonable doubts. Many people are put off by the need to constantly charge the batteries of their glasses.

The solution may be to purchase equipment with passive 3D. Fortunately, there are many devices on the market that can provide excellent quality.

Check if 3D glasses are included, and if so, how many. And if they are not available or there are not enough, then make sure that you can purchase them separately (catalog with 3D glasses here). After all, if the equipment uses active 3D, then most likely it will be necessary to purchase accessories from this particular manufacturer. By the way, due to the cheapness of polarized glasses, they are often supplied with equipment literally in bulk.

3D TVs without glasses

Even expensive and fancy glasses create a number of inconveniences. Therefore, electronics manufacturers are actively working to create devices that can do without these accessories. And you can already find similar solutions on the market — the first such TV was introduced in 2011 by Toshiba.

In early 2014, Sharp introduced an 85-inch 3D TV, which does not require special glasses to view

At the heart of a 3D TV without glasses is an autostereoscopic screen. It is covered with a special film, which consists of many prismatic microscopic lenses (lenticular film). Thanks to her, the rays from the screen are refracted and the image enters the eyes from different angles. Further, everything happens according to the same scenario, when the brain perceives the image as three-dimensional.

It would seem that everything is simple. But the trouble is that you need to sit in front of such a screen motionless, at a certain distance, at a certain angle. In addition, the cost of TVs is too high.

However, the problem of cost is traditional for any new technology. A decade will pass, and televisions with lenticular film on the screen will be installed even in kitchens. As for the disadvantage with the position of the user in front of the screen, complex technologies are used to eliminate it. So, the TV can recognize who and how is sitting in front of it, transmitting its own image to each of the viewers. In this case, the 3D image is divided into separate images according to the number of users. The solution is far from elegant, but the manufacturers are not yet able to offer anything more suitable.

The principle of operation of 3D TVs without glasses. The main disadvantage is that the user must always be in a certain place in front of the screen

Another method of creating a 3D image without glasses is called barrier parallax. In this case, a special grating is placed in front of the screen, due to which each eye sees only its own image. This technology is still very crude, work is underway to improve it. And it is quite possible that it will be used in conjunction with lenticular technology. In the meantime, all technical flaws have not been eliminated, we cannot do without 3D glasses.

Present and future of 3D technologies

A few years ago, there were suggestions that in the near future stereo television will completely replace ordinary television. In fact, this did not happen. And although supported hardware has become the norm, this opportunity is not always taken advantage of.

A serious obstacle to this is the mandatory wearing of glasses. And if they can still be tolerated when watching movies, then few people want to use glasses when watching the news or weather reports. The situation will certainly change after the mass distribution of televisions, which will make it possible to do without these "crutches". Until then, 3D is only good for watching movies.

But most likely, even then, conventional 2D television will remain popular for a long time, mainly because of its cheapness and simplicity. The emergence and mass distribution of technology does not always lead to the extinction of the old one. So, videophones have not surprised anyone for a long time, but people have not stopped making ordinary voice calls.

And science fiction writers and futurologists, meanwhile, dream of real 3D television, when it comes to showing really three-dimensional objects, and not about a banal illusion. But this is definitely not going to happen anytime soon.