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3d is an abbreviation for the term three-dimensional or three-dimensional, that is, three-dimensional. The ordinary world around us is also three-dimensional. The eyes, observing what is happening around, perceive the surrounding objects, which are at different distances from them. Since a person has two eyes, each of them sees an object from its own angle. Two slightly different images are sent to the brain, where they are immediately analyzed. As a result of a complex, but very fast recalculation, the brain produces a three-dimensional image that allows, for example, to estimate whether an approaching car is far or close, you can already cross the road, or it is still worth waiting. 3D technology uses a very similar principle; when watching a movie, the eyes constantly get two different pictures of the action taking place on the screen. It should be borne in mind that when watching a regular film, 24 statistical frames per second are scrolled in front of the viewer. The brain needs some time to process each of them, and while it does this, the previous frame is replaced by the next one, creating the impression of movement. In a 3d movie, essentially the same thing happens, only the number of frames is doubled. The eyes are offered 48 images per second, alternating left-right, left-right. The picture for the left eye is broadcast on a slightly different light wave than that for the right one. If you just look at the screen, you will not see anything but a muddy, rippling picture. Special glasses are equipped with lenses with built-in polarizing filters capable of transmitting light beams of a certain length. Each eye sees only "its own" picture, forwards information to the brain, and that, according to a familiar, long-established algorithm, models a three-dimensional image from the received frames. 3d glasses have already become a common attribute of the modern viewer, but this does not mean at all that from now on it will be possible to watch movies only with them. Technology is constantly evolving and perhaps in the near future there will be another way to polarize the image. Three-dimensional cinema will move to a new stage of development, will become even more voluminous, interesting and exciting.

3D Printer Construction

A 3D printer with FDM printing technology consists of a metal body (frame), a compartment for securing a spool of filament, an extruder and a desktop. Single-extruder 3D printers can print single-color objects, multi-extruder printers multi-color. The more extruders a printer has, the more expensive it is. Electronic filling and heating and cooling system are hidden under the printer body. Some models have LCD displays for displaying current print information and USB ports.

Consumables for 3D printing

A typical 3D printer with FDM printing technology uses thin polymer filaments with diameters of 1.75 mm and 3 mm to work. Such filaments are most often made of PLA or ABS plastic, but there are also combined materials with the addition of wood fibers, nanopowders, biodegradable particles, phosphorizing pigments and other components. The yarns are supplied in spools weighing from 0.5 kg to 1.5 kg. A spool of polymer filaments is placed in a special compartment of the 3D printer, and the end of the filament is fed into the extruder nozzle.

3D-modeling of an object

Before you can 3D print a 3D object, you need to create a digital version of it in a 3D modeling program. You can use ready-made samples that are available on the Internet, or prepare 3D models for printing yourself. The prepared model is loaded into a special program for generating G-code, which divides the object into thin horizontal layers and forms a chain of commands that the printer can understand. The finished object is sent to print.

Layer-by-layer formation of an object

A 3D printer with FDM printing technology forms physical objects layer by layer, squeezing a thin stream of molten material onto the working platform. The printer moves the extruder exactly according to the digital model, so the printed physical object fully matches its virtual prototype. Most often, the printer's extruder, from which the soft plastic is squeezed out, moves while working on a fixed working platform, but there are devices in which both the extruder and the working platform are mobile. The printing process begins with the bottom layer, after which the printer applies the next layer on top of the first. Melted plastic, getting into the working area, cools and hardens very quickly.

3D printing of support structures and object finishing

To prevent the object from deforming during printing, the 3D printer prints supporting structures (aka support structures, support structures). Such structures are not always printed, but only if there are voids or overhanging parts in the object structure. Imagine you want to print a plastic mushroom on a thin stem. With the base of the leg, it rests on the desktop, no support is needed here, but for the edges of the cap, which seem to hang in the air, such support will be simply necessary. After printing, the support structures can be easily removed by hand or cut with a sharp blade or knife.

For sure, everyone has heard about the existence of 3D printing, and facts about the new possibilities of this technology are constantly slipping in the news. Not so long ago, three-dimensional printing was used only in production conditions and by a few enthusiasts, today you can easily buy a 3D printer for use in everyday life. With the help of such devices print all sorts of things: from decorative knick-knacks for the home to prostheses, weapons and even buildings. The prospects for 3D printing are so fantastic that few people today can fully imagine them. Until then watching the future come, we study the principles of operation of a 3D printer, its capabilities and advantages, and also figure out which 3D printer to choose for use in everyday life.

Despite the fact that the technology of three-dimensional printing has been on everyone's lips only for the last few years, its appearance is worth looking for in the last century. The pioneer in this field was Charles Hull, which in 1984 developed the technology of three-dimensional printing, and a little later patented the technique of stereolithography, which is now widely used today. At the same time, the company developed and created the first industrial three-dimensional printer, which actually marked the beginning of a new era.

The 90s were the time of the emergence of new developments in the field of three-dimensional printing, thanks to which 3D printers found application in industrial conditions and began to be used for prototyping. The peak of technology development falls on the XXI century, and we ourselves are becoming eyewitnesses of how three-dimensional printing conquers new heights by leaps and bounds. Today, printing can be carried out with different materials, and not only plastics and metal, but also cloth, paper, ceramics, food and even living cells.

In 2005, it became possible to print in color, and in 2006 a printer was created that can print about half of all its own components. In 2014, the first printers appeared with an almost unlimited print area. With the help of this device, they have already tried to create a full-fledged house using concrete as the main material. It took no more than a day to erect such a structure. Already in 2016, it was presented first building built using 3D printing In Dubai. In February 2017, Russia also unveiled a house printed entirely at the construction site. This year, a six-axis printer was also developed, with which complex elements will be much easier to print without the need for supporting structures. At the moment, the development of printers that can print human organs, prostheses, implants, car bodies and even food.

How does a 3D printer work? Just about complicated

In short, a 3D printer is a device for creating three-dimensional objects by layer-by-layer printing. The range of materials used for printing is constantly expanding and we can safely assume that in the future it will include most of the substances known to us. Bye The most popular print media are thermoplastics and photopolymer resins.

General principle of operation 3Dprinter can be represented as follows:

Printing features depend on the technology used by the printer, so it makes sense to deal with the most common at the moment.

Types of 3D printers and printing features of each

The most commonly used technology todayFDM-prints as wellSLA- printing. What is behind these incomprehensible abbreviations, and what other developments exist in this area?

FDM printing method

FDM-technology(Fused Deposition Modeling) is a filament deposition technology. Today, this method of 3D printing is considered the most common, at the same time it belongs to one of the oldest methods. The principle lies in the layer-by-layer fusing of the plastic filament along the contour of the model.

Thermoplastics are used for printing, which are supplied as coils or rods. Most often typed PLAandABSplastics, including nylon, polyamide, polycarbonate, PET (aka polyethylene terephthalate, which is used to create plastic bottles) and some other substances.

The principle of operation is as follows:

a thread of material is placed in an extruder, where it is melted under the influence of a heating element, and then squeezed out through a nozzle onto the working surface;
the extruder moves along the path specified by the software, and builds the object layer by layer;
if it is necessary to print a complex object, then two types of material can be used: one for the model, the second for creating supports (it is usually soluble, or just very easily breaks off the object). Supports need to be printed if the object has elements hanging in the air that cannot be created without supporting elements, the printer will simply have nothing to print on. Everything is clearly presented in the figures below;
after the formation of the first layer, the platform goes down by the thickness of one layer, and the extruder squeezes out a new portion of the material, the process is repeated many times;
at the end of printing, it remains to separate the auxiliary elements.

Model and supporting elements

FDM technology allows the use of production-grade thermoplastics, so printed objects receive excellent mechanical, chemical and thermal strength. The technology is simple, clean and suitable for office or home use.

The same principle is used by 3D-pens. These are actually miniature printers. These pens are designed for drawing three-dimensional drawings. The user can squeeze out instantly solidifying plastic from it, giving it any shape and getting funny products. The device is more intended for pampering, but the idea is interesting, and designers can make many interesting home decor items.

SLA printing method, or stereolithography

SLA technology (laser stereolithography) involves the use of liquid photopolymer resins for printing, which tend to solidify under the influence of a laser or similar energy source. The method allows you to get objects with very precise geometry, because the layer thickness can reach a record 15 microns, therefore it is already widely used in dentistry in the manufacture of implants and in jewelry to create blanks with an abundance of complex parts.

How it works 3D-printers using the method of laser stereolithography can be briefly described as follows:

the working platform is immersed in a bath with liquid photopolymer to a thickness of one layer (15-150 microns);
the impact of the laser on the walls of the future object. The laser beam literally traces the shape of the object on the photopolymer, which, in turn, is set by the software. Laser irradiation causes the material to polymerize at the points of contact with the beam and solidify;
the platform is immersed a little deeper into the bath with liquid photopolymer, and the immersion depth corresponds to the size of the layer. The laser again affects areas of the material that should be part of the printed object;
the process is repeated layer by layer until the modeled object is printed;
the technology also requires the printing of supporting elements. They are made from the same photopolymer;
after completion of printing, the object is immersed in a bath in special solutions to remove excess and clean the model;
final - ultraviolet irradiation for the final solidification of the photopolymer.

The technology is progressive, but it requires the purchase of expensive consumables.

Other types of printing

Less common, but no less interesting and promising are the following three-dimensional printing methods:

What is the best 3D printer for home use?

Looking ahead, we note that while the cost of household 3D printers remains relatively high, but in the future we have every chance to observe a reduction in the cost of technology. Remember, when mobile phones were introduced, they were also available only to the very wealthy.

The goals of using a home 3D printer can be absolutely anything: from simple pampering and acquaintance with new technology to printing useful small things in the household and prototype models for business. In any case, when choosing, pay attention to the following key characteristics of the device:

print resolution (print accuracy) Is the smallest possible layer height that the printer can print. Specifies the resolution in micrometers (thousandth of a millimeter). The lower the layer height, the less noticeable the transition between them will be, and the smoother the surface of the printed object will be. On the other hand, the smaller the layer, the longer it will take for the printer to print and the higher the load on all of its elements. Resolution depends on technology (SLA allows you to print more accurately than FDM), printhead accuracy, software settings and selected print media;
Samples with different layer thicknesses
print speed directly depends on the accuracy: the higher the accuracy, the slower the growth rate of the model.
print area tells you what size the object can be printed on the printer. In other words, this is the area of possible reach of the printhead along the horizontal X and Y axes, as well as along the vertical Z axis. Usually, the print area is expressed in three numbers - this is the height, length and width of a conventional parallelepiped (for example, 20 * 30 * 30 mm). For delta printers, the printable area is in the form of a cylinder, so its height and diameter are indicated;
the type of plastic used for printing. In domestic conditions, it is plastics that are used, and these can be ABS and PLA plastics, some models can print with both types of materials. The ability to print with one or another type of plastics is explained by the presence or absence of platform heating. If you have not yet decided what you will print, then it is better to choose a model that supports the maximum number of materials;
manufacturer country... European countries and the USA produce high-quality, but expensive devices, are imported in small quantities, and service maintenance is difficult. Chinese devices are inexpensive, the quality is often poor, but in order to indulge, such printers will do. There are also Russian-made printers: with good quality, they please with the possibility of service.

Interesting options for household 3D printers

MakerBot Replicator 2

A high-quality American-made printer, prints using FDM technology, the minimum layer thickness is 100 microns (0.1 mm). Printing area - 285 * 153 * 155 mm, PLA and ABS plastics are used for printing. The maximum printing speed is 40 mm per second, or 24 cm 3 / hour. The body is made of steel, there is an LCD screen, the weight is 11.5 kg. Although the model was released in 2013, it is still actively used for household printing. The cost is $ 3100.

PrintBox3D One

The printer is of domestic production, prints using FDM technology, the minimum layer thickness is 50 microns, the dimensions of the working platform are 185 * 160 * 150 mm. The device prints ABS and PLA plastics, it is equipped with a heated platform. Approximately $ 1,700, designed for educational and design use.

Wanhao Duplicator i3 v2

A budget option for those who want to master the technology and indulge in. It costs about $ 500, prints with different types of plastic with an accuracy of 100 microns, the print area is 200 * 200 * 180 mm. The build quality is excellent.

PICASO 3D Designer

It prints using FDM technology, like all household 3D printers today, uses ABS and PLA plastics for printing, incl. nylon. The printing accuracy is 50 microns, the working platform is 200 * 200 * 210 mm, the maximum speed is 30 cm 3 / hour. The device is equipped with a heated platform, cost $ 1,700.

Hercules 3D printer

Not a bad device from the Russian company IMPRINTA, it prints with different types of plastic, printing accuracy is 50 microns. Heated platform, maximum temperature - 120 0 С. Print speed - 40 cm 3 / hour. Price $ 1150.

As a summary of the main pros and cons of 3D printing

3D printing is a promising direction with great potential. To dot the "i" in the study of the issue of three-dimensional printing, we give its main advantages:

Existing cons:

3D printing is the future of medicine and industry, and the ability to quickly prototype and model, which is invaluable to engineering. Who knows, maybe in 5-10 years we will be just as easy to download models of cups or shoes and print them on our own home printer, as today we download and watch films.

3D imaging technology appeared a long time ago, but remained so unadvanced that it held back its growth. Today, well-known consumer electronics companies have set themselves the goal of developing new technologies that allow the use of 3D for cinemas, as well as the introduction of 3D TVs.

Before dealing with 3D in television, you need to understand why we perceive the world in 3D?

The reason for our three-dimensional perception is that objects that are around us, we see with two eyes, the so-called binocular vision. How are the eyes positioned? At a short distance from each other, so each eye provides a different image. If you look at the same object, alternately closing the left and then right eyes, the image does not change, however, it will shift. This phenomenon is called parallax and it plays the most important role in a person's ability to perceive the depth of an object.

The brain functions in such a way that when processing various images received from each of the eyes, it brings them into a combined image, in which the distance and depth of objects is revealed to us. The offset between images from each eye increases with the distance of the subject. Considering visual perception, 3D technology is built in such a way that each eye sees a slightly different image, and as a result, it appears to be three-dimensional to us.

3D glasses

Today, two technologies of three-dimensional image are known: a technology that involves watching a movie with and without special glasses. The second version is under development. Despite the promise of Japanese manufacturers - to release 3d TVs by the end of this year, you can watch a 3D movie only by wearing special glasses.

The color filter technology, or anaglyph glasses, was proposed in 1853 by Wilhelm Rohlmann (Germany). In order to obtain the effect of a three-dimensional image, it is necessary to look through glasses with glasses of contrasting colors: red-green, red-blue (the latter option is characterized by a comparatively better quality), although it is still problematic to provide a full three-dimensional image in this way.

How does 3d imaging technology work in this case? Images of different color tones overlap to create a 3D effect. Today, the more common red-blue color combination, which provides the most acceptable quality. In 2003, the USA released the Spy Kids 3D movie. If we consider the advantages of such glasses, then this is their affordable cost, and the disadvantage is not always excellent reproduction of shades, sometimes discomfort during viewing and dizziness.

Polarized glasses are used in IMAX 3D and RealD cinemas all over the world. In short, it should be noted that when using a special polarized film, the effect of light polarization is possible, which makes it possible to selectively filter out light particles. Two images, polarized and orthogonal to each other (observance of a right angle), come from a cinema projector onto a special screen, covered with silver.

Polarized glasses have two polarized filters. Each filter is designed to process light of only one polarization. As a result, different glasses give different images for each of the eyes, which together allows you to view the movie with a 3D effect. Systems such as RealD use circularly polarized light. Both images are polarized right-circularly or left-circularly. Circularly polarized light maintains consistent contrast and brightness during viewing, which is noticeable when changing viewing angles.

What are the benefits of using polarized glasses? It should be noted that at the moment this is one of the best 3D technologies, having proven image quality with excellent color reproduction and the same detail. Glasses of this type are not electronic, they are passive, which reduces their cost. Glasses can be easily transferred from one mode to another - from 2D to 3D. As disadvantages, it should be noted that the technology in question is still not widespread enough in the production of advanced 3D TVs.

Renowned manufacturers such as Sony, Panasonic and Nvidia have championed active shutter imaging technology. The method provides sequential and alternate formation of each of the images on an ordinary liquid crystal monitor. Given the twice the frame rate, the screen should function at double the refresh rate when compared to the frequencies of standard LCD monitors and televisions. In this case, the frequency must correspond to a minimum of 60 (Hz), based on which, 3d TVs operate with a frequency of at least 120 Hz.

The active shutter of the glasses allows each eye to perceive only the image reserved for it on the monitor. Special active glasses of this type work as a shutter and provide selective perception of images on the display for each eye. The lenses of such special glasses function like a shutter and are synchronized with the transmission of the TV image. How it works? The eyes are closed in turn and each of them is assigned only the corresponding image for perception. Active shutter glasses contain liquid crystals, some of which are opaque and can be used as a shutter. The active shutter glasses effect can be used in combination with Bluetooth, infrared or radio waves.

Active shutter TVs and displays can already be found on store shelves. Nvidia sells active shutter systems for 3D virtual games. The upcoming models include a 240Hz refresh rate that will help minimize glare and unevenness. On top of that, 3d technology will give obvious improvements when watching sports programs and scenes with speed effects.

Advantages of the technology: reliability, completeness of the development demonstrated by CES 2010 with the support of Sony and Panasonic; reduction of visual fatigue.

Disadvantages: high cost of glasses, need for batteries. Of course, it is not a lot of fun if the batteries run out in the midst of viewing. Active shutter glasses reduce the brightness of the picture. Frequencies in the 120Hz range may not be sufficient to reproduce scenes with moving objects, resulting in image unevenness and glare.

(7 Votes)

A futuristic helicopter passes low over the heads of the audience, robotic marines clad in ex-armor sweep away everything in their path, a huge space shuttle shakes the air with the roar of engines - so close and frighteningly real that you involuntarily squeeze your head into your shoulders.

James Cameron's recently released Avatar or three-dimensional computer game make the viewer, sitting in an armchair in front of the screen, feel like a participant in a fantastic action ...

Very soon, alien monsters will be walking in every home with a modern home theater.

But how is a flat screen capable of displaying a three-dimensional image?

A person in a three-dimensional volumetric space ...

We see the same object with our left and right eyes from different angles, thus forming two images - a stereo pair. The brain connects both pictures into one, which is interpreted by consciousness as three-dimensional.

Differences in perspective allow the brain to determine the size of an object and the distance to it. Based on all this information, a person receives a spatial representation with the correct proportions.

How the volumetric image appears

In order for the picture on the screen to appear three-dimensional, each eye of the viewer, as in life, must see a slightly different image, from which the brain will put together a single three-dimensional picture.

The first movies in 3D format, created with this principle in mind, appeared on the screens of cinemas back in the 50s.

Since the growing popularity of television was already a serious competitor to the film industry, the cinematographers wanted to force people to leave the sofas and head to the cinema, seducing them with visual effects that no TV could provide at that time: color images, wide screen, multichannel sound and , of course, three-dimensionality.

The volume effect was created in several different ways.

Anaglyph method (anaglyph - in Greek "relief"). In the early days of 3D cinema, only black and white 3D films were released. In each appropriately equipped cinema, two cinema projectors were used to display them.

One was projecting the film through a red filter, the other was displaying slightly horizontally displaced film frames, passing them through a green filter.

Visitors put on light cardboard glasses, in which, instead of glasses, pieces of red and green transparent film were installed, so that each eye saw only the desired part of the image, and the audience perceived the "three-dimensional" picture.

However, both cinema projectors must be directed strictly at the screen and work absolutely synchronously.

Otherwise, double image is inevitable and, as a result, headaches instead of viewing pleasure - in viewers.

Such glasses are also well suited for modern color 3D films, in particular, recorded using Dolby 3D. In this case, one projector with light filters installed in front of the lens is sufficient.

Each of the filters allows red and blue light to pass through to the left and right eyes. One image is bluish, the other is reddish. The light filters in the glasses let through only the appropriate frames intended for a particular eye.

However, this technology makes it possible to achieve only insignificant 3D effect, with shallow depth.

Shutter method. Optimal for watching color films. In contrast to the anaglyphic method, this method involves alternately showing the images intended for the left and right eyes by the projector.

Due to the fact that the interleaving of images is carried out at a high frequency - from 30 to 100 times per second - the brain builds a holistic spatial picture and the viewer sees a whole three-dimensional image on the screen.

Previously, this method was called NuVision, now it is more often called XpanD. To view 3D films using this method, shutter glasses are used, in which two optical shutters are installed instead of glasses or filters.

These small light-transmitting LCD matrices are capable of changing the transparency on a command from the controller - either dimming or brightening, depending on which eye at the moment it is necessary to submit the image.

The shutter method is used not only in cinemas: it is also used in televisions and computer monitors. In a movie theater, commands are sent using an IR transmitter.

Some 90s PC shutter glasses were connected to the computer using a cable (modern models have a wireless interface).

The disadvantage of this method is that shutter glasses are complex electronic devices that consume electricity. Consequently, they have a fairly high (especially compared to cardboard glasses) cost and significant weight.

Polarization method. In the field of cinema, this solution is called RealD. Its essence is that the projector alternately demonstrates film frames in which the light waves have a different direction of polarization of the light flux.

The special glasses required for viewing are equipped with filters that transmit only light waves polarized in a certain way. So both eyes receive images with different information, on the basis of which the brain forms a three-dimensional picture.

Polarized glasses are somewhat heavier than cardboard ones, but since they operate without a power source, they weigh and cost significantly less than shutter glasses.

However, along with the polarizing filters that are installed on cinema projectors and glasses, this method requires an expensive screen with a special coating to show 3D films.

At the moment, preference has not finally been given to any of the named methods. It should be noted, however, that fewer cinemas are working with two projectors (using the anaglyph method).

How 3D movies are made

The use of sophisticated techniques is required already at the shooting stage, and not only while watching 3D films.

To create the illusion of three-dimensionality, each scene must be filmed simultaneously with two cameras, from different angles.

Like human eyes, both cameras are placed close to each other, and always at the same height.

3D technologies for home use

To view 3D Movies DVD still uses simple cardboard glasses, a legacy of the distant 50s. This explains the modest result - poor color reproduction and insufficient image depth.

However, even modern 3D technologies tied to special glasses, and this state of affairs, most likely, will not change soon.

Although Philips introduced a prototype of a 42 "glasses-free 3D LCD TV in 2008, the technology will reach market maturity in at least 3-4 years.

But the release of 3D-TVs working in tandem with glasses, at the international exhibition IFA 2009, several manufacturers announced at once.

For example, Panasonic intends to release 3D TV models by mid-2010, just like Sony and Loewe, relying on the shutter method.

JVC, Philips and Toshiba are also striving to climb the 3D podium, but they prefer the polarization method. LG and Samsung are developing their devices based on both technologies.

Content for 3D

Blu-ray Discs are the main source of 3D video content. The content is transferred to the image source via HDMI.

To do this, the TV and the player must support the appropriate technologies, as well as the recently adopted HDMI 1.4 standard - only it provides simultaneous transmission of two 1080p data streams. So far, devices supporting HDMI 1.4 can be counted on one hand.

3D technology on the computer

Initially, viewing a three-dimensional image on a computer was available only with the help of glasses or special virtual reality helmets. Both of them were equipped with two color LCD displays - for each of the eyes.

The quality of the resulting image when using this technology depended on the quality of the LCD screens used.

However, these devices had a number of disadvantages that frightened off most buyers. Forte's cyber helmet, which appeared in the mid-90s, was bulky, ineffective and reminiscent of a medieval torture device.

The modest resolution of 640x480 pixels was clearly not enough for computer programs and games. And although later more advanced glasses were released, for example, the LDI-D 100 from Sony, but even they were quite heavy and caused severe discomfort.

Having withstood an almost ten-year pause, the technologies for the formation of stereo images on the monitor screen entered a new stage in their development. It is good news that at least one of the two major manufacturers of graphics adapters, NVIDIA, has developed something innovative.

The 3D Vision complex costing about 6 thousand rubles. Includes shutter glasses and IR transmitter. However, to create a spatial 3D image using these glasses, you need the appropriate hardware: the PC must be equipped with a powerful NVIDIA video card.

And in order for the pseudo-three-dimensional picture not to flicker, a monitor with a resolution of 1280x1024 pixels must provide a screen refresh rate of at least 120 Hz (60 Hz for each eye). The first laptop equipped with this technology was the ASUS G51J 3D.

So-called 3D profiles for more than 350 games are now also available and can be downloaded from the NVIDIA website (www.nvidia.ru). These include both modern action games, such as Borderlands, and previously released ones.

Continuing the theme of computer games, the polarization method is an alternative to the 3D shutter. To implement it, you need a monitor with a polarizing screen, for example, Hyundai W220S.

A 3D image becomes available with any powerful ATI or NVIDIA graphics card. However, this reduces the resolution from 1680x1050 to 1680x525 pixels, since the interlaced output of frames is used.

Based on materials from ComputerBild magazine

The section is constantly updated with useful things:

Write your opinion below in the comments. Let's discuss.

While there was competition between conventional LCD and LCD TVs with LED backlighting, manufacturers began to release 3D TVs. Wanting to keep up with each other, the world leaders in the production of LCD TVs began to develop and release surround television systems. And only such models appeared at the exhibition CES and IFA in 2010, as their production has already begun by many firms. According to forecasts, in 2010 about 400 thousand 3D TVs will be sold, and in 2011 sales will increase to 3.4 million, and in 2012 it is planned to sell 50 million of them, of which 80% will be LCD, and the rest are plasma panels.

Some countries have even started broadcasting 3D programs on cable and satellite channels. Contracts are concluded for the production of such content and the sale of films in the 3D standard.

Japanese TV leaders Sony and Panasonic decided to compete seriously for the 3D TV market with Korean rivals LG and Samsung. To do this, they used their opportunities from sponsoring the Olympics and the 2010 FIFA World Cup. Sony is demonstrating its systems at all trade shows and predicts that 40% of the company's profits in 2012 will come from TV sales. And in 2010, prices for such models will be about $ 200 higher than conventional LCD panels.

All this suggests that manufacturing firms are investing heavily in the promotion of 3D television products, and this gives rise to expectation of a serious decline in price.

3D TV

How a 3D TV works

All models of 3D TVs presented at the exhibitions have Full HD resolution, as well as the means of providing volumetric content. These exhibitions aroused great interest among visitors. And if the possibilities of 3D image are already implemented in projectors and TVs, then high-definition 3D television is a different technology.

3D in cinemas

Three-dimensional images in movies have long been possible to watch in cinemas. Glasses with multi-colored lenses were used during the first viewing. Here the principle of image separation for the left and right eyes was used. The glasses were still with a red and green lens.

The use of polarizing glasses has become a great success in three-dimensional cinema. This technology was called IMAX 3D. Then two projectors were used and two images were obtained on the screen. one is horizontally polarized and the other is vertically polarized... With special glasses, the left and right glass allowed only the image with its polarization to pass through, and a three-dimensional image was obtained. With this method, it was possible to obtain a high-quality and bright image. The disadvantage was that when the head was tilted, the picture brightness and quality changed.

A newer technology for surround cinema is RealD. This technology used one digital projector, which projected frames for the left and right eyes alternately at a high frequency. So that the quality of the picture does not depend on the tilt of the head, circular polarization was used. Clockwise polarization was applied for one frame, and counterclockwise for the other.... With this method, a three-dimensional image was obtained of higher quality and more natural. Only by virtue of technological features, this technology can be used only in small halls while maintaining quality.

All these methods use special silvered fabrics for screens and sophisticated equipment for projectors in cinemas. It is not rational to use such technologies at home, and even more so in television equipment. The use of polarization in televisions is impossible on the entire screen area.

3D on Full HD TVs

In the previously used models of volumetric video (CRT TVs, projectors), the principle of dividing the image resolution by two was used. And one frame of the stereo image was displayed on even lines, and the other frame on odd lines. With this method of dividing the image, the vertical resolution of the CRT TV was reduced to 300 lines. And in the case of using Full HD, the reduction will be up to 540 lines at a native resolution of 1080 vertical pixels. An image was displayed for each eye separately, and at one moment in time one eye saw its half-frame, and the other did not see anything at that moment in time. In the next half-frame, it was the other way around, and already the other eye saw the image, but the first did not.

To ensure HD resolution in 3D TVs, that is, 1080 vertical dots, you can apply the same principle as before: output frames separately for each eye in turn. At the same time, make it so that each frame sees only one eye, and the other eye already sees its own, that is, the next frame of the image.

In a regular TV using this technology, frames will go at a frequency of 25 Hz, because the frame rate is 50 Hz, and if you divide the image for each eye, then you get 50: 2 = 25 frames per second. And if in cinemas films are shown at a frequency of 24 frames per second, then there we see reflected light from a long distance. On TVs at a frequency of 25 Hz, flickering will be noticeable and your eyes will hurt. If we take the 24p mode, which is implemented in modern televisions for watching movies with a frequency of 24 frames per second, then in fact the frame rate is taken to be a multiple of 24 and is 72 or 96 Hz.

It turns out that Full HD 3D will not be able to play well on conventional HD LCD TVs. For comfortable viewing, you need a frequency of 60 Hz for each half-frame (this value was derived as a result of research), that is, the total frame rate should be 120 Hz, which means that even 100 Hz TVs will not be suitable for displaying 3D. Moreover, each frame must be output with a resolution of 1920 x 1080 pixels, which corresponds to Full HD.

Response time on 3D TVs

To ensure a clear image, each pixel on the screen needs to change its position 120 times per second, while each time it will display an image of a different half-frame. And if in 2D this is not so critical to obtain good definition, then in 3D it cannot be allowed that the frames overlap, which means that a very small pixel response time is needed. According to this parameter, panels are the best for surround television, because they have a pixel response time less than in LCD matrices. But in plasma panels, another drawback is the decline of the pixel luminescence and manufacturers apply additional methods to reduce this luminescence.

For lcd panels, the response time should be less than 3 miles seconds, and not all matrices reach this value. Therefore, when viewing 3D on LCD TVs, strobe and stalling effects may occur, especially in fast scenes. When viewing a surround TV signal on projection TVs, a rainbow effect may occur. Therefore, according to the reviews of exhibition visitors, the best result when showing the content of three-dimensional television is obtained from plasma panels.

But given the development of the LCD TV market and the interest of manufacturers, we can expect that they will soon overcome the shortcomings in the response time of the matrices.

Transferring content to 3D TVs

Another challenge arises with the delivery of Full HD 3D content from source to TV. First, there should be reading from the disk over a two-channel system, and then also transmit such a signal. And for transmission already HDMI 1.4 required, because the HDMI 1.3 interface, which is widespread today, may not cope with the transmission of 120 frames per second in Full HD quality.

Glasses for 3D TVs

And for receiving 3D images, all the same glasses are used. True, they are now active, that is, they use the built-in chip to control the shading of the desired lens. Previously, passive glasses with polarizing filters were used. Wireless synchronization scheme is used to control active glasses with the image on the TV screen, realized using infrared radiation.

In technology systems 3D television without glasses is based on the principle of image separation for each eye with the help of microlenses on the screen. Here, one frame is divided into an image for each eye separately, which means that a high resolution Full HD is not obtained in any way.

Today, obtaining Full HD surround television systems is associated only with the use of glasses.

Of course, with the development of television broadcasts in surround television systems and the release of more and more films the development of 3D TVs will only pick up speed.