The composition of the plasma panel. Plasma vs LCD TV: which is better? ("Plasma vs.

What is plasma?

The basis of each plasma panel is the actual plasma, i.e. a gas consisting of ions (electrically charged atoms) and electrons (negatively charged particles). Under normal conditions, the gas consists of electrically neutral, i.e., particles that do not have a charge.

Individual gas atoms contain an equal number of protons (particles with a positive charge in the nucleus of an atom) and electrons. The electrons 'compensate' for the protons, so that the total charge of the atom is zero. If a large number of free electrons are introduced into the gas by passing an electric current through it, the situation changes radically. Free electrons collide with atoms, `knocking out` more and more electrons. Without an electron, the balance changes, the atom acquires a positive charge and turns into an ion. When an electric current passes through the resulting plasma, the negatively and positively charged particles tend to each other. Amidst all this chaos, particles are constantly colliding.

Collisions "excite" the gas atoms in the plasma, causing them to release energy in the form of photons. Plasma panels mainly use inert gases - neon and xenon. When `excited', they emit light in the ultraviolet range, invisible to the human eye. However, ultraviolet light can also be used to release photons in the visible spectrum.

The history of the creation of plasma panels or screens

Everything was for the defense. Even if the scientists themselves thought they were working for their own pleasure. They were wrong.

It was 1963. Donald Bitzer of the University of Illinois was working on learning systems to display not only letters and numbers, as was the case at the time, but also graphics. Successes in this field were not important.

Bitzer eventually recruited a team to work on a new project. He was going to find out how a matrix of neon cells would work if a high-frequency electric current was passed through them.

For his work, Bitzer attracted Gene Slottov and student Robert Wilson. How things were going, now it’s impossible to find out, only all three names are inscribed in the patent for the invention.

In the summer of 1964, the first plasma display appeared. It looked very remotely similar to modern panels. It's funny, but it consisted of only one single pixel. Now there are millions of them in each panel.

Naturally, a display of one pixel is not a display. However, less than ten years later, acceptable results were achieved. In 1971, Owens-Illinois sold a license to manufacture Digivue displays.

In 1983, the University of Illinois made nothing less than a million dollars by selling a plasma license to IBM. It is now that she has begun to gradually fade into the shadows, and then there was no stronger player in the computer market at all.

Plasma displays were first used in PLATO computer terminals. This PLATO V model illustrates a display of the monochromatic orange glow seen in 1981.

The same year saw the introduction of the IBM 3290 Information Panel, the first mass-produced commercial product.

Already in 1982, they began to produce Plasmascope displays for monitoring launches of ground-based ballistic missiles. True, at that time it did not help them much. In general, computer companies quickly abandoned plasma panels. IBM was the last to abandon their production in 1987. By that time, only the Pentagon was producing "plasma" in limited quantities. He always had enough money.

By the early 1990s, commercial LCDs were on the scene, and things weren't going well for plasma. Then only black-and-white plasma panels were produced and, in general, they could not compete with LCD. Yes, and problems with contrast did not please - this indicator was lame even in the most advanced models. However, "plasma" took root in Matsushita, now known as Panasonic. In 1999, a forward-thinking 60-inch prototype was finally produced with remarkable brightness and industry-leading contrast.

In the late 90s. In the last century, Fujitsu managed to alleviate the problem somewhat by improving the contrast of their panels from 70:1 to 400:1. By 2000, some manufacturers were claiming contrast ratios of up to 3,000:1 in their panel specifications, now it's already 10,000:1+. The manufacturing process for plasma displays is somewhat simpler than for LCD manufacturing. Compared to the production of TFT LCD displays, which require the use of photolithography and high-temperature technologies in sterile clean rooms, `plasma` can be produced in dirtier workshops, at low temperatures, using direct printing.

Plasma screen technology

Based on the information in the video signal, a powerful beam of electrons "lights up" thousands of small dots called pixels. On most systems, there are only three colors of pixels - red, green, and blue - that are evenly distributed across the entire screen. By mixing these colors in various proportions, televisions can recreate the entire gamut of shades.

The image on the plasma panel is created by glowing small colored fluorescent bulbs. Each pixel is made up of three fluorescent lights - red, green and blue. Due to the different brightness of the bulbs, like CRT TVs, plasma panels can reproduce the entire color gamut.

The central element of fluorescent light bulbs is plasma - a gas consisting of free ions (charged atoms) and electrons (negatively charged particles). IN normal conditions A gas is made up of uncharged particles, that is, atoms with an equal number of protons (positively charged particles located in the nucleus of an atom) and electrons. Negatively charged electrons neutralize positively charged protons, so that the total charge of the atom is zero.

If you add a large amount of free electrons to the gas by passing an electric discharge through it, the situation changes very quickly. Free electrons colliding with atoms<выбивают>of which are valence electrons. When an electron is lost, the atom acquires a positive charge and thus becomes an ion.

When an electric current is passed through the plasma, negatively charged particles are attracted to the positively charged region of the plasma, and vice versa.

Moving rapidly, the particles are constantly colliding with each other. These collisions excite the gas atoms in the plasma, and they emit photons.

The xenon and neon atoms used in plasma panels emit photons of light when excited. These are mainly ultraviolet photons that are not visible to the naked eye, but as we will see in the next paragraph, they can activate visible photons of light.

Inside the panel: gas and electrodes

In plasma panels, xenon and neon are contained in hundreds of small micro-chambers located between two glasses. On both sides, between glasses and microchambers, there are two long electrodes. The control electrodes are located under the microchambers, along the rear glass. Transparent scanning electrodes surrounded by a dielectric layer and coated protective layer magnesium oxide, located above the microchambers, along the front glass.

The electrodes are arranged crosswise across the entire width of the screen. Scanning electrodes are located horizontally, and control electrodes - vertically. As you can see in the diagram below, the vertical and horizontal electrodes form a rectangular grid.

For gas ionization in a certain microchamber, the processor charges the electrodes directly at the intersection with this microchamber. Thousands of such processes occur in a fraction of a second, charging each microcamera in turn.

When the intersecting electrodes are charged (one negative and one positive), an electrical discharge passes through the gas in the microchamber. As mentioned earlier, this discharge sets the charged particles in motion, as a result of which the atoms of the gas emit ultraviolet photons.

plasma screen

Plasma panels are a bit like CRT TVs - the display coating uses a phosphor-containing compound capable of glowing. At the same time, they, like LCDs, use a grid of electrodes with a protective coating of magnesium oxide to transmit a signal to each pixel cell. The cells are filled with internt gases - a mixture of neon, xenon, argon. An electric current passing through the gas causes it to glow.

In essence, a plasma panel is a matrix of tiny fluorescent lamps controlled by the panel's built-in computer. Each pixel cell is a kind of capacitor with electrodes. An electric discharge ionizes gases, turning them into plasma - that is, an electrically neutral, highly ionized substance consisting of electrons, ions and neutral particles.

Being electrically neutral, the plasma contains an equal number of electrons and ions and is a good current conductor. After the discharge, the plasma emits ultraviolet radiation, causing the phosphor coating of the pixel cells to glow. Red, green or blue component of the coating. In fact, each pixel is divided into three sub-pixels containing red, green or blue phosphor. To create a variety of shades of colors, the intensity of the glow of each sub-pixel is controlled independently. In kinescope TVs this is done by changing the intensity of the electron flow, in `plasma` - using 8-bit pulse code modulation. The total number of color combinations in this case reaches 16,777,216 shades.

The fact that plasma panels themselves are a source of light provides excellent vertical and horizontal viewing angles and excellent color reproduction (unlike, for example, LCD screens, which usually need a matrix backlight).

Inside the display

In a plasma TV, the 'bubbles' of neon and xenon gases are placed in hundreds and hundreds of thousands of small cells compressed between two glass panels. There are also long electrodes between the panels on both sides of the cells. The `addressed` electrodes are located behind the cells, along the rear glass panel. The transparent electrodes are coated with a dielectric and a protective film of magnesium oxide (MgO). They are located above the cells, along the front glass panel.

Both `grids` of electrodes cover the entire display. The display electrodes are arranged in horizontal rows along the screen, and the address electrodes are arranged in vertical columns. As you can see in the figure below, the vertical and horizontal electrodes form the base grid. In order to ionize the gas in a single cell, the plasma display computer charges those electrodes that cross on it. It does this thousands of times in a tiny fraction of a second, charging each display cell in turn. When the intersecting electrodes are charged, an electrical discharge passes through the cell. The flow of charged particles causes the atoms of the gas to release photons of light in the ultraviolet range. Photons interact with the phosphor coating of the inner wall of the cell. As you know, phosphorus is a material that emits light itself under the action of light. When a photon of light interacts with a phosphorus atom in a cell, one of the atom's electrons goes to a higher energy level. The electron is then displaced backward, releasing a photon of visible light.

Pixels in a plasma panel consist of three sub-pixel cells, each of which has its own coating - red, green or blue phosphorus. During the operation of the panel, these colors are combined by a computer, new pixel colors are created. By varying the rhythm of the current pulsing through the cells, the control system can increase or decrease the intensity of each subpixel's glow, creating hundreds and hundreds of different combinations of red, green, and blue flowers. The main advantage of the production of plasma displays is the ability to create thin panels with wide screens. Since each pixel's luminosity is individually determined, the image comes out stunningly bright, even when viewed from any angle. Normally, the saturation and contrast of the image is somewhat inferior best models CRT TVs, but quite lives up to the expectations of most buyers. The main disadvantage of plasma panels is their price. It is impossible to buy a new plasma panel cheaper than a couple of thousand dollars, hi-end class models will cost tens of thousands of dollars. However, over time, the technology has improved significantly, prices continue to fall. Now plasma panels are beginning to confidently crowd out CRT TVs. this is especially noticeable in rich, technologically advanced countries. In the near future, `plasma` will come to the homes of even poor buyers.

Service life of plasma panels

The service life of plasma panels is measured relative to the half-life of combustion of phosphorus gas. Once all the phosphor has burned out, the image quality is significantly degraded from what it was originally, and the panel may need to be replaced, the manufacturers say. In the case under consideration, the combustion half-life is exactly half the life of the panel.

After 1000 hours of operation, the brightness level is approximately 94% of the original.

Since the phosphor burns at a constant rate, the image quality deteriorates in proportion to the decay rate. You can think of this process as simply the "glow" of phosphorus. Immediately after the Plasma TV is turned on, the phosphor contained in the screen starts to slowly burn off. Thus, there is less and less gas for the screen to glow. As a result, the brightness and color saturation gradually decrease. After 1000 hours of operation, the brightness level is approximately 94% of the original; after 15000-20000 - about 68% (i.e. 68% of phosphorus glows). Much depends on the level of contrast. If you want your plasma display to last longer, lower the contrast ratio in the OSD menu. If you set the contrast ratio to maximum, the phosphor will burn out much faster.

Most manufacturers claim that their panels will last approximately 30,000 hours at "normal" contrast levels (around 50%). Recently, however, some manufacturers, notably Sony and Panasonic, have stated that the picture quality of their new plasma TVs begins to decline only after 60,000 hours of use. We are a little skeptical about statements of this kind. Although we are aware of how much has been done to increase the service life of plasma TVs (for example, increased resistance of green phosphorus), we will still believe these data only after they are confirmed in real conditions, and not just theoretically.

From a buyer's point of view, 30,000 hours should be enough, since CRT TVs have about the same lifespan. On the other hand, according to a study by US statistical companies, the average family watches TV 4 to 6 hours a day on average; accordingly, the service life of the plasma panel will be from 13 to 20 years.

How to extend the life of the panel?

Follow the steps below to extend the life of your Plasma TV:

1) Adjust the BRIGHTNESS and CONTRAST levels according to the viewing conditions. Try not to increase the Contrast level unnecessarily - this will only burn phosphorus faster. In brightly lit rooms, you may need to increase the Contrast; Lower the Contrast level at night or in dark rooms.*
2) Do not leave a static image on the screen for long periods of time (more than 20 minutes). Otherwise, an afterimage will appear on the screen.
3) Turn off the plasma panel after viewing.
4) Use the Plasma TV in a well ventilated area. Thanks to a high-quality ventilation system, the plasma screen will last longer.

* Recently, most manufacturers "carry out" the option of adjusting the contrast on the remote control; there is no need to enter the OSD menu.

How to avoid burn-in of the plasma panel?

In addition to the lifespan of plasma TVs, consumers often wonder about screen burn-in, which manufacturers claim is the result of panel misuse. All this is very serious; accordingly, the question arises: What is the burn-in of plasma panels, and how should they be used to avoid such an effect?

Most often, the burn-in effect is found on the screens of ATMs. We are all well aware of the result of the same picture - the "insert card" section of the menu - being displayed on the screen for too long. Have you noticed how this gray inscription looms in the background during the entire operation with an ATM? This is the screen burn effect; he is constant.

Without getting into technical details, burn-in is a damaged pixel whose phosphorus has been prematurely used up and therefore glows less than surrounding pixels. The reason lies in the fact that the damaged pixel "remembers" the color with which it glowed for a long time. This color is "burnt in" on the glass of the plasma screen (hence the term "burn in"). Damaged phosphor cannot glow in the same way as normal phosphor.

Pixels usually do not fade singly, as this effect occurs when a static image is displayed on a plasma screen for a long time, such as web logos, computer icons, Internet browser windows, etc.

Adviсe

Do not leave a static image on the panel screen. Always turn off the panel after viewing. Do not pause the DVD for a long time.
Plasma screens are more likely to burn in during the first 200 hours of use. "Fresh" phosphorus burns faster than already used. This means that newer plasma displays are more likely to experience "ghosting" after a static image has been projected for a long time. This is probably due to the fact that, due to the high brightness, "fresh" phosphorus explodes. Usually, this effect disappears after a while on its own. If you leave a static image on the screen for a long time, the halo effect may be followed by screen burn.

Precautionary measures: Be careful when you turn on the panel for the first time. Set the CONTRAST level to no more than 50% - exceeding it will lead to more intensive combustion of phosphorus and, as a result, screen burnout. Use the anti-burn-in features provided, such as the grayscale feature, which eliminates the ghosting effect by recalibrating the brightness of the pixels. Ideally, this feature should be used approximately every 100 hours of using the plasma display. (Note: These processes affect the phosphorus resource, so they should only be used when needed.)

Some plasma panels burn out more often than others. It has been observed that users of AliS-type panels - manufactured by Hitachi and Fujistu - are more likely to experience screen burn-in.
Use screen saver features such as power management, image slider (vertically and horizontally), and auto screen saver. Check the user manual for more information.

It is important to understand that image quality is directly related to screen burn-in. You want to purchase a plasma TV to watch 4:3 TV programs. Do not leave black streaks on the Plasma TV screen for a long time; therefore, TV programs are best viewed in widescreen (16:9). With good scaling, you will not notice a significant difference in image quality.

High-end TVs are more resistant to burn-in, although not completely. Of all the plasma panels we tested, NEC, Sony, Pioneer, and Panasonic were the least prone to burn-in. But despite this, experts NEVER, regardless of the quality of the panel, leave a static image on the screen for more than an hour.

You must understand that some applications are not suitable for use with plasma displays.

For example, a static display of flight schedules at an airport. You can often be surprised when you walk into an airport to see an absolutely burnt-out plasma monitor hanging from the ceiling. The only thing they are used for is projecting the same information for hours. This is one of the many examples where plasma panels are misused. (Note that airports have recently begun to use new software that constantly moves the image to avoid burn-in of the plasma monitor.)

conclusions

Burn-in is not a reason not to buy plasma TVs. With proper use, most plasma display users will never experience image retention. Sometimes a halo effect may occur, but this is not a cause for concern. In fact, sloppy handling - that is, indifference to what and how long a plasma panel shows - is the main cause of screen burn-in.

The service center "MTechnic" carries out preventive maintenance, diagnostics and repair of LCD TVs, repair of projection TVs and repair of plasma panels of the following brands: Sony (Sony), Thomson (Thomson), Toshiba (Toshiba), Panasonic (Panasonic), Lg (El G) , Philips (Philips), Grundig (Grundik), Samsung (Samsung), RFT (RFT) and other manufacturers.

Coverage area: Moscow, Zelenograd, Moscow region (MO). For your convenience, our courier service works (free of charge), more details in the "contacts" section

Denisova Ksenia Sergeevna 985

The principle of operation of plasma panels is the glow of special phosphors under the influence of voltage. Like any product, a plasma panel has certain advantages and disadvantages.

At present, the most acute and relevant is not the question of its choice, but the question of the expediency of its purchase as a whole.

The main advantages of plasma panels include the following:

A high level of contrast that distinguishes them from liquid crystal (LCD) and electro-beam (CRT) monitors and televisions. The image looks very saturated and of high quality, so the plasma panel is recommended for use in home theater equipment.

Plasma panels do not have the inertia inherent in LCD panels, which makes the response time of these panels short. This makes dynamic scenes more natural, without trailing trails for moving characters.

Prices in online stores:

TV bracket Wize WU65 (37-65", up to 40 kg), black	compyou.com	755 R

Unlike LCD panels, plasma panels have a large viewing angle. In addition, the quality and properties of the image do not depend on the viewing position.

Plasma panels, unlike CRTs, are distinguished by a very high definition of the picture, due to the absence of problems with beam convergence that are typical for CRTs.

Unlike CRT, long-term viewing of plasma panels does not tire the eyes, as there is no flickering of the image.

Plasma panels, unlike CRTs, do not have such a disadvantage as sensitivity to electromagnetic fields. And you can easily place acoustic speakers made with magnetic materials near plasma panels, which you can't do with CRT panels.

The main disadvantages of plasma panels include:

High prices, which amount to several thousand dollars.

High consumption of electrical energy. For example, LCD monitors of the same size consume about half as much electricity.

The high consumption of electrical energy causes serious heating of plasma panels, as a result of which they have to be forced to cool with the help of fans. Fans, in turn, are a source of extraneous noise. However, it should be noted that modern fans have a reduced noise level, in addition, while viewing, you are at a sufficient distance from the panel itself.

One disadvantage similar to CRT is phosphor burn-in. The highest degree of "burn-in" is affected by stationary areas of the image, for example, channel logos. This suggests that plasma panels are the least suitable for use as TVs. It should be noted that the manufacturers of plasma panels are actively eliminating this drawback, and their service life at the moment is similar to the service life of other types of panels.

The image unit of plasma panels, as well as other types, is a pixel or dot. Due to the large pixel sizes of plasma panels compared to other types, there is an increase in their overall dimensions(from 30 inches diagonally). Thus, based on the fact that the distance of the audience from the panel should be 4-5 sizes of its diagonal, the size of the room should be at least 3-4 meters. Considering also the fact that the rear speakers should be placed behind the audience, the minimum width of the room should be about 4-5 meters.

Big weight.

By purchasing a plasma panel, you, as a rule, do not purchase a full-fledged TV. Since the plasma panel is only a display device, you will need to purchase an additional DVD player, TV tuner, good kit acoustics. Of course, many models already have a built-in TV tuner and acoustics, but their purchase, in my opinion, is not advisable, as this will deprive you of high-quality sound.

Plasma panel selection

The modern market is characterized by a wide variety various models plasma TVs. But which model is right for you? We offer you a list of recommendations that will help you with the selection and purchase of a suitable plasma TV model for you.

One of the important characteristics is the screen size.

It is logical that the larger the screen size of a plasma TV, the more expensive its price. It should be noted that the size of the screen does not characterize the quality of the image. Therefore, many people, depending on the amount of money they have, tend to buy a plasma TV with the largest wide screen possible. However, first of all, you need to consider whether this TV will fit in your living room.

Where to place a plasma TV?

Make it a rule that wide-screen plasma TVs are uncomfortable to watch from close range, and, conversely, small-screen plasmas are uncomfortable to watch from long distances. Therefore, before purchasing, you need to measure your room and evaluate the space in which you will place the plasma TV.

Prices in online stores:

183 to 213 cm corresponds to 30 inches 213 to 244 cm corresponds to 35 inches 244 to 274 cm corresponds to 40 inches 274 to 305 cm corresponds to 45 inches 305 to 335 cm corresponds to 50 inches 335 to 366 cm corresponds to 55 inches from 366 cm or more corresponds to 60.65 inches

Most Plasma TVs can either be hung on the wall or put on a special box. Decide in advance which option is most suitable for you and purchase a stand, wall mounts or bedside table when buying a TV. Perhaps one of the listed devices is already included in the kit.

Choose resolution

There are two types of resolution: ED (Enhanced Definition) and HD (High Definition). Choose which one you need. An HD Plasma TV offers higher quality than an ED TV. When assessing the quality of resolution, attention should be paid to number 2. For example, a resolution of 852 x 480 would be ED. HD resolution refers to TVs with a second resolution digit greater than 720.

Connectivity

Plasma TVs can be used for a variety of purposes. Therefore, when choosing a TV, be sure to check all the connections you need, namely: DVI and HDMI ports, S-Video, A / V inputs necessary to connect a game console or video camera.

Check the warranty period

You should carefully check the warranty period of the plasma TV you decide to purchase. You may want to extend this period.

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SonyXEL-1 (11" MY 2007-2008)

The Sony XEL-1 TV is a real “baby”, you can’t call it otherwise. The diagonal is only 11 inches (27 cm), rather, it is customary to see it on a tablet or laptop. But this TV left a mark in history much larger than its size! The Sony XEL-1 was the world's first Organic Light Emitting Diode (OLED) TV, launched in late 2007 in Japan and 2008 in other regions. For that time, mass production of 11-inch OLED TVs was a breakthrough, and along the way, the XEL-1 became "the largest in the world."

A fabulously expensive model for its size ($2,499 in the US and for some reason 200,000 rubles in Russia), of course, did not gain popularity, but it became an excellent demonstration of the capabilities of OLED. Infinitely deep blacks, pure and rich colors - all this could be seen on the 11-inch screen. The thickness of the panel together with the body was 1 cm, and the entire filling moved into a massive stand. Looking at this curiosity in exhibition showrooms and stores, any of us thought of only one thing: “I wish they did the same thing, only with a large screen!” Well, before the dream came true, it was only a few years to wait ...

LG 77EC970V (77 inches, MY 2014-2015)

LG has successfully mastered the production of 55-inch OLED TVs, but does not stop there. 65-inch OLED Ultra HD models will be on sale soon, and a little later (at least abroad) 77-inch OLED Ultra HD TVs will appear on sale. This novelty simply has no analogues: other manufacturers, including pioneers from Sony, are not yet ready to mass-produce OLED, especially in comparable sizes and quantities.

Needless to say, the LG 77EC970V 77-inch 4K OLED TV immediately became "the world's first and largest 4K OLED"? As you can see, exactly 7 years have passed, and a modest 11 inches turned into a solid 77. Not bad arithmetic! And in future plans there is also a “bendable” version of the TV. It is able to change the radius of curvature at the wave of the remote control. What can I say, according to LG's plans, then fully flexible OLED displays are just around the corner.

SamsungUE110S9 (110", MY 2013)

While manufacturers have struggled to produce OLED efficiently, the simpler and more conservative LCD technology has captured virtually every segment of the TV market. Samsung has continued to lead in terms of production and sales of LCD TVs for several years in a row. Naturally, from time to time you have to play an image "card" in order not to disappear from the list of hot headlines containing the big words "the biggest" or "the first in the world."

So, at CES 2013, Samsung showed a huge 110-inch model UE110S9 - the world's largest Ultra HD LCD TV, consisting of a single seamless panel. True, it was produced exclusively to order at a modest price of $ 142,000 for the basic version. But you could still play around with certain options that raised the cost even higher ...

PanasonicTH-152UX1W (152 inches, MY 2010)

In its own way, the legendary model. It is enough just to read a huge number of comic reviews from fictitious "owners" all over the Runet to understand what they are talking about. Plasma panel Panasonic TH-152UX1W - the owner of an absolute record in size, period. Just think: the diagonal of the screen is a whopping 152 inches (386 cm). This TV is so big that plasma panels for it were made from piece blanks in a separate workshop. For obvious reasons, happy buyers had to separately consider the issue of installing a TV, because with such dimensions it simply did not fit into most openings. Well, at least Panasonic took over the delivery of the TV to the client.

The panel had a physical resolution of 4096x2160 (4K), supported 3D and generally showed an outstanding image. The plot of any film took on truly rampant proportions on such a screen. The same can be said about the cost of this pleasure: about 30 million rubles (at the old rate).

CSEED 201 (201-inch, MY 2011)

Lecture #5

Question #1

Overview of flat screen playback devices

Until now, in the vast majority of mass-produced televisions, masked kinescopes have been used as devices for displaying color television information. However, they have serious drawbacks. The main one is a significant mass, bulkiness and complexity in manufacturing.

Competitors of kinescopes can be called display devices in the form of flat panels. The basic principles underlying their operation have been known for a long time, and, as practice has shown, flat panels did not provide the proper image quality for a long time. Meanwhile, their cost is very high. In recent years, thanks to numerous research and technological improvements, the situation has changed dramatically.

Currently, several types of flat panels are known: gas discharge, liquid crystal, vacuum luminescent, semiconductor (LED). They have advantages over mask tubes not only in terms of a number of technical parameters, but also in terms of mass production capabilities. They use cheaper materials (for example, liquid crystals are made from meat processing waste), the use of expensive rare-earth phosphors is reduced, expensive high-precision metal for masks, copper wire for deflecting systems, bulky and environmentally harmful glass production for the manufacture of flasks are not required. The service life of the panels is longer than that of mask kinescopes.

But a significant drawback of flat panels, which hinders their use in household appliances, still remains the high cost of the process of their manufacture.

Since the late 1980s, liquid crystal display (LCD) panels have been widely used as laptop monitors. Unfortunately, with the growth of the screen diagonal, the cost of such panels increases dramatically. The disadvantages of the first LCD panels should also include their inertia, non-linearity of the modulation characteristic and a limited viewing angle.

In parallel with liquid crystal panels, the technology of gas discharge panels has been rapidly developed. Their development began in the early 90s. The Japanese company Fujitsu, since 1993, has been producing gas discharge panels with diagonals of 40 cm or more. Sony and Nec also joined the work.

Plasma panels

The principle of operation of the plasma panel (plasma display panel PDP) is based on the glow of the phosphors of the screen under the action of ultraviolet rays arising from an electrical discharge in a plasma (rarefied gas).

Structurally, the plasma panel consists of two glass plates, on which translucent electrodes (tires) are applied for switching image rows (on the front glass) and image columns (on the rear glass, which is the substrate) (Fig. 5.1). On the inner surface of the front transparent glass plate, opposite each subpixel, there are two thin-film electrodes: scanning electrode and illumination electrode. On the outer surface of the rear glass plate across all pixels is located addressing electrode. Thus, a rectangular matrix is formed, the cells of which are located at the intersection of the row and column electrodes. A special profile is formed on the substrate glass in the form of glass ribs, which isolate neighboring cells from each other. Alternating strips of primary colors of phosphors are deposited on the inner surface of the substrate glass. R, G, IN, forming a triad. During the manufacture of such a panel, air is pumped out of the internal volume between the glass plates, this volume is filled with a rarefied gas (neon, xenon, helium, argon or a mixture of them), which is the working "body" during operation, after which the panel is sealed.

Figure 5.1 - The design of the plasma panel

The plasma panel works as follows. With the help of external "sweep" devices, control voltages are applied to the electrodes of the rows and columns of the matrix. Under the action of voltage between the initiated row and column tires in the corresponding cell of the matrix, an electric discharge occurs in the gas through the resulting plasma (ionized gas). This discharge causes powerful ultraviolet radiation, which causes the phosphor in this cell to glow. Since there are separating "barriers" between neighboring cells, the electrical discharge is localized within one single cell and does not affect neighboring cells. And so that the “sing” ultraviolet does not cause the glow of the “alien” phosphor, a special ultraviolet-absorbing coating is applied to the side surfaces of the dividing ribs.

The operation of the plasma panel consists of three stages (Figure 5.2):

initialization, during which the ordering of the position of the charges of the medium and its preparation for the next stage (addressing) takes place. At the same time, there is no voltage on the addressing electrode, and an initialization pulse is applied to the scanning electrode relative to the backlight electrode, which has a stepped form. At the first stage of this pulse, the ordering of the arrangement of the ions of the gaseous medium occurs, at the second stage, the discharge in the gas, and at the third stage, the ordering is completed.

addressing, during which the pixel is prepared for highlighting. A positive pulse (+75 V) is applied to the address bus, and a negative pulse (-75 V) is applied to the scan bus. On the backlight bus, the voltage is set to +150 V.

backlight, during which a positive pulse is applied to the scan bus, and a negative pulse equal to 190 V is applied to the backlight bus. The sum of the ion potentials on each bus and additional pulses leads to an excess of the threshold potential and a discharge in a gaseous medium. After the discharge, the ions are redistributed at the scan and illumination buses. The change in the polarity of the pulses leads to a repeated discharge in the plasma. Thus, by changing the polarity of the pulses, a multiple discharge of the cell is ensured.

One cycle "initialization - addressing - highlighting" forms the formation of one image subfield. By adding several subfields, it is possible to provide an image of a given brightness and contrast. In the standard version, each frame of the plasma panel is formed by adding eight subfields.

Thus, when a high-frequency voltage is applied to the electrodes, gas ionization or plasma formation occurs. A capacitive high-frequency discharge occurs in the plasma, which leads to ultraviolet radiation, which causes the phosphor to glow: red, green or blue (Fig. 5.3).

Figure 5.2 - Illustration of the stages of the plasma panel

Figure 5.3 - Illustration of the operation of one sub-pixel of a plasma panel

Let's analyze the main technical and consumer characteristics of plasma panels

Diagonal, resolution

The diagonals of plasma panels start at 32 inches and end at 103 inches. Of this entire range, as mentioned above, 42-inch panels with a resolution of 853x480 pixels are the best sold in Russia so far. This resolution is called EDTV (Extended Definition Television) and means "high-definition television". Such a TV will be enough for a comfortable pastime, since in Russia there is no free high-definition television (High Definition TV - HDTV) yet. However, HDTVs tend to be more technically advanced, process the signal better, and are even capable of "pulling" it up to HDTV levels. In addition, you can already buy films recorded in HD DVD format in stores. When choosing an HDTV TV, pay attention to the supported signal format. The most common is 1080i, that is, 1080 interlaced lines. Interlacing is considered to be not very good, since there will be visible teeth on the edges of objects, but this disadvantage is leveled by high resolution. Support for the more advanced 1080p progressive scan format has so far only been found on fairly expensive TVs since the ninth generation. There is also an alternative 1080i format - this is 720p with a lower resolution, but with progressive scan. It will be difficult to tell the difference between the two pictures by eye, so ceteris paribus 1080i is preferable. However, a large number of TVs simultaneously support both 720p and 1080i.

When choosing a diagonal, first of all, keep in mind - the larger it is, the farther the observer should be from the TV (about 5 screen heights). So in the case of a 42-inch panel, the observer must be at least three meters away from it. Otherwise, the discreteness of the image structure will be quite noticeable due to the relatively large pixel size of the plasma panel.

Aspect Ratio(aspect ratio) All plasma TVs have 16:9 aspect ratio panels. A standard 4:3 TV picture will look fine on such a screen, just the unused screen area on the sides of the picture will be filled with black or gray if the TV allows you to change the fill color. The TV may have functions to stretch the image to fill the screen, but as a result of this operation, as a rule, there is a slight distortion of the image. So far, only a limited number of test digital channels broadcast in 16:9 format in Russia. By default, this aspect ratio is used only in HDTV. Brightness

There are two brightness-related panel characteristics, the panel brightness and the overall TV brightness. The brightness of the panel cannot be judged on the finished product, because there is always a light filter in front of it. The brightness of the TV is the observed brightness of the screen after the light passes through the filter. The actual brightness of the TV never exceeds half the brightness of the panel. However, the specifications of the TV indicate the original brightness, which you will never see. This is the manufacturer's first marketing gimmick. Another feature of the data specified in the specifications is related to the method of obtaining them. In order to save energy and protect the panel from overload, its brightness per dot decreases in proportion to the increase in the total area of illumination. That is, if you see a brightness value of 3000 cd / m2 in the characteristics, you should know that it is obtained only with a small illumination, for example, when several white letters are displayed on a black background. If we invert this picture, we will get, for example, 300 cd/m2. Contrast

Two characteristics are also associated with this indicator: contrast in the absence of ambient light and in the presence. The value given in most specifications is the contrast measured in the absence of background lighting. Thus, depending on the lighting, the contrast can vary from 3000:1 to 100:1. Interface connectors

The vast majority of plasma TVs have at least the following connectors: SCART, VGA, S-Video, component video interface, as well as conventional analog audio inputs and outputs. Consider these and other connectors in more detail. SCART transmits analog video and stereo audio simultaneously. Through HDMI, you can transmit an HD signal in 1080p resolution along with eight-channel audio. Due to the high bandwidth and miniaturization of the connector, the HDMI interface is already supported by many camcorders and DVD players. And Panasonic supplies with its PDP a remote control with the HDAVI Control function, which allows you to control not only the TV, but also other equipment connected to it via HDMI. VGA is a common computer analog connector. Through it, you can connect a computer to the PDP. DVI-I is a digital interface for connecting the same computer. However, there is another technique that works through DVI-I. S-Video - most often used to connect DVD players, game consoles and, in rare cases, computer. Provides good image quality. Component video interface - an interface for transmitting an analog signal, when each of its components goes through a separate cable. Thanks to this, the component signal is the highest quality of all analog ones. Similar RCA connectors and cables are used for sound transmission - each channel is transmitted via its own wire. A composite video interface (on one RCA connector) uses one cable and, as a result, loss of color and clarity of the image is possible. power usage

The power consumption of the Plasma TV varies depending on the picture being displayed. The level specified in the specification reflects maximum value. So, for example, a 42-inch plasma panel with a completely white screen will consume 280 watts, and with a completely black screen - 160 watts.

The main advantages and disadvantages of plasma panels

Advantages

Firstly, The image quality of plasma displays is considered to be a reference, although only recently the "problem of red", which in the first models looked more like a carrot, was finally solved. In addition, plasma panels compare favorably with their competitors by high brightness and image contrast: their brightness reaches 900 cd/m2 and contrast ratio up to 3000:1, while for classic CRT monitors these parameters are 350 cd/m2 and 200:1, respectively. It should also be noted that the high definition of the PDP image is maintained on the entire working surface of the screen. Secondly, plasma panels have a short response time, which allows you to easily use the PDP not only as a means of displaying information, but also as TVs, and even, when connected to a computer, play modern dynamic games. It is important to note that plasma panels do not have such a significant disadvantage of LCD monitors as a significant deterioration in the quality of the image on the screen at large viewing angles. Thirdly, in plasma panels (however, as well as in liquid crystals) there are fundamentally no problems of geometric distortions of the image and convergence of rays, which are a significant drawback of CRT monitors. Fourth, having the largest screen area among all modern visual information display devices, plasma panels are exceptionally compact, especially in thickness. The thickness of a typical panel with a screen size of one meter usually does not exceed 10-15 centimeters, and the weight is only 35-40 kilograms.

Fifth, plasma panels are quite reliable. The declared service life of modern PDPs of 60 thousand hours suggests that during all this time (approximately 6.7 years of continuous operation) the screen brightness will decrease by half against the initial one. At sixth, plasma panels are much safer than kinescope TVs. They do not create magnetic and electric fields that have a harmful effect on humans and, moreover, do not create such inconvenience as the constant accumulation of dust on the surface of the screen due to its electrification. Seventh, PDPs themselves are practically unaffected by external magnetic and electric fields, which allows them to be used without problems as part of a "home theater" together with powerful high-quality speaker systems, not all of which have shielded speaker heads. disadvantages

First of all, this is a relatively low image resolution compared to LCD panels, due to big size image element. But, given the fact that the optimal distance from the monitor to the viewer should be about 5 of its height, it is clear that the graininess of the image observed at a small distance simply disappears at a large distance.

Also, a rather significant drawback of the plasma panel is the high power consumption, which rapidly increases with increasing diagonal of the panel. This fact leads not only to an increase in operating costs, but high power consumption seriously limits the scope of the PDP, for example, makes it impossible to use such monitors, for example, in laptop computers. But even if the problem with the power supply is solved, it is still not economically profitable to manufacture plasma displays with a diagonal of less than thirty inches.

Liquid crystal panels

Liquid crystal panels (LCD panels) are a light valve device that modulates the luminous flux from an external light source. liquid crystal panels (LCD) – panels) uses the ability of an amorphous substance to change its optical properties in an electric field. There are residential complexes – translucent and reflective panels. From the back side, the translucent type LCD panel is illuminated with a uniform light flux. Under the action of voltage between the initiated row and column tires in the corresponding cell of the matrix, the optical transparency of the amphora substance changes. Luminous flux passing through an LCD matrix with three types of color cells RGB, modulated in brightness and color. So the LCD screen – panel, a color image is synthesized.

Currently, LCD panels are most widely used in computer technology as monitors, as well as televisions. LCD panels are ten times more economical than plasma panels. The advantages of LCD panels should also include high manufacturability and relatively low cost.

The principle of operation of liquid crystal matrices is based on the property of the molecules of a liquid crystal substance to change their spatial orientation under the influence of an electric field and to have a polarizing effect on light rays. In a multilayer matrix structure, which is a rectangular array of many separately controlled elements (pixels), a layer of liquid crystals is placed between glass plates, on the surface of which grooves are applied. Thanks to them, in all elements of the matrix, it is possible to orient the molecules in an identical way, and, due to the mutually perpendicular arrangement of the grooves of the two plates, the orientation of the molecules changes as they move away from one of them and approach the other by 90 degrees (Figure 5.4).

Figure 5.4 - Illustration of the principle of operation of the LCD panel

The polarized light passed through such a layer of a liquid-crystal substance (see Fig.) also changes the polarization plane by 90. Therefore, the structure, in which input and output polarization filters are added with mutually perpendicular polarization axes ( a And b), turns out to be transparent to the external light flux, which is partially weakened when passing through the input polarizer.

Being under the influence of an electric field, the molecules of the liquid crystal layer change their orientation, and the angle of rotation of the plane of polarization of the light flux decreases markedly. In this case, most of the light flux is absorbed by the output polarizer. Thus, by controlling the level of the electric field, it is possible to change the transparency of the matrix elements.

LCD panels are produced passive and active. In color TVs, active ones are predominantly used.

The active panel (Figure 5.5) is based on two plane-parallel plates, one of which has horizontal electrodes corresponding to rows and vertical electrodes (columns). The number of decomposition lines determines the horizontal resolution. At their intersections, thin-film transistors (TFT) are strengthened, the gates of which are connected to horizontal electrodes, and the sources - to vertical ones. The transistor drains form the first plates of miniature capacitors (cells) corresponding to the image elements. A translucent metallization layer on a second glass plate, located in parallel at a distance measured in microns, works as the second lining of capacitors. Between the plates introduced an organic substance with the properties of a liquid crystal. This liquid is chemical composition close to cholesterol. To calibrate the gap between the plates, a number of microscopic glass cylinders are introduced into the liquid layer, the diameter of which determines the gap. Polaroid films are superimposed on the panel on both sides, the polarization planes of which are rotated by 90one relative to the other. In the absence of voltage on the LC capacitor, the substance rotates the plane of polarization by another 90 . As a result, light passes freely through the cells. When voltage is applied to the capacitor plates, the structure of the LC substance changes, which causes an additional rotation of the polarization plane. When the angle of its rotation in the substance decreases to zero, the cell stops transmitting light. This property also allows to receive the image. To make it colored, the panel contains a matrix light filter consisting of "red", "green" and "blue" cells, the centers of which are located opposite the elementary capacitors of the panel and alternate along the line (R  G  B  R). In adjacent rows, the color cells of the light filter are shifted horizontally by one, so that the image does not have a visually noticeable vertical structure. A backlight is installed behind the panel.

LCD panels are designed to work in a well-defined television standard. In the simplest receivers, both fields of a television frame are reproduced on the same line elements without interlacing. In this case, the number of horizontal electrodes should be equal to the number of active lines in the field of the television image. For the domestic D/K standard, the number of horizontal electrodes must be equal to . If a television signal of another standard, for example M, where the number of lines in the field is 262.5, is applied to such a panel, then the image size will be compressed vertically. When increasing the screen size diagonally over 15 cm, it is necessary to reproduce both fields separately and provide interlaced scanning. Then the number of row electrodes in the panel must be increased to the number of active rows in the frame.

Figure 5.5  LCD Screen Construction

In a large format LCD TV to ensure signal reception different systems it is expedient to use transformations of standards by two-dimensional filters. To control the panel, the vertical and line scanning devices included in its composition are used. The vertical scan device provides alternate selection of line electrodes by applying voltage pulses to them. The horizontal scanner alternately selects the column electrodes, which receive discrete signal samples. These samples charge the cell capacitors. Depending on the voltage on them, the angle of rotation of the plane of polarization of light passing through the LC substance changes. As a result, the brightness of the selected image element changes. As you know, in a mask kinescope, an electron beam highlights triads of a phosphor. Each triad corresponds to an image element. In this case, it is impossible to control the sequence of luminescence of the phosphor dots included in the triad. In the LCD panel, it is possible to separately control each color point corresponding to the intersection of the horizontal and column electrodes, which allows applying various laws of image decomposition. Samples of the image signal corresponding to the selected row can be preliminarily recorded in the register and simultaneously applied to all column electrodes. Samples of the signal can also be applied to the electrodes of the columns in turn with a given alternation law. Since the human visual apparatus does not perceive the coloring of small details, then in small format panels, the following image elements along the line can be created not from three, but from one color component. For example, the first element  R, the second  G, the third  B, the fourth  R, and so on. At the same time, the clarity of the image horizontally increases three times compared to a mask kinescope, where each element contains three phosphor dots of different colors. To reduce clock frequencies in the scanners, alternate control of even and odd rows and columns is used. In accordance with this, the scanner blocks themselves are made of two parts. Horizontal scanning chips are located to the right and left of the LCD panel, horizontal scanning chips  top and bottom. Since the LCD screen is a valve device, a backlight is required for its operation. Usually it is a fluorescent lamp. A reflector and diffuser are also needed to ensure uniform illumination. The brightness of the lamp should be relatively high, since the LCD panel, even in the maximum transparency mode, absorbs most of the light flux.

Relatively recently appeared LCD TV with LED backlight(colloquially referred to as LED TV(short for L night E meeting D iodine T ele V ision) - a TV with a liquid crystal display, the screen of which is illuminated by an LED matrix (LED).

From a consumer perspective, LED-backlit LCD TVs feature four improvements over EL-backlit LCDs:

Improved contrast;

Improved color rendering;

Reduced power consumption;

Small body thickness.

Plasma Display Panel (PDP)

Only fifteen or twenty years ago, science fiction writers unanimously predicted the appearance of huge and completely flat television screens in the future. And now the fairy tale has finally come true, and anyone can buy such a screen.

The device of plasma panels

The principle of operation of the plasma panel is based on the glow of special phosphors when exposed to ultraviolet radiation. In turn, this radiation occurs when electrical discharge in a highly rarefied gas environment. With such a discharge, a conductive “cord” is formed between the electrodes with a control voltage, consisting of ionized gas (plasma) molecules. That is why gas-discharge panels operating on this principle are called “ gas-discharge"or, which is the same -" plasma” panels.

Design

The plasma panel is a matrix of gas-filled cells enclosed between two parallel glass surfaces. Neon or xenon is usually used as the gaseous medium.

The discharge in the gas flows between the transparent electrode on the front side of the screen and the address electrodes passing along its back side. The gas discharge causes ultraviolet radiation, which, in turn, initiates the visible glow of the phosphor.

In color plasma panels, each screen pixel consists of three identical microscopic cavities containing an inert gas (xenon) and having two electrodes, front and back. After a strong voltage is applied to the electrodes, the plasma will begin to move. In doing so, it emits ultraviolet light, which hits the phosphors at the bottom of each cavity.

Phosphors emit one of the primary colors: Red, green or blue. The colored light then passes through the glass and enters the viewer's eye. Thus, in plasma technology, pixels work like fluorescent tubes, but creating panels from them is rather problematic.

The first difficulty is the pixel size. Sub-pixel The plasma panel has a volume of 200 µm x 200 µm x 100 µm, and several million pixels need to be laid on the panel, one by one.

Secondly, the front electrode should be as transparent as possible. For this purpose, it is used indium tin oxide because it conducts current and is transparent. Unfortunately, plasma panels can be so large, and the oxide layer so thin, that when large currents flow, there will be a voltage drop across the resistance of the conductors, which will greatly reduce and distort the signals. Therefore, it is necessary to add intermediate connecting conductors made of chromium - it conducts current much better, but, unfortunately, is opaque.

Finally, you need to choose the right phosphors. They depend on the desired color:

Green: Zn 2 SiO 4:Mn 2+ / BaAl 12 O 19:Mn 2+
Red: Y 2 O 3:Eu 3+ / Y0.65Gd 0.35 BO 3:Eu 3
Blue: BaMgAl 10 O 17:Eu 2+

These three phosphors produce light with a wavelength between 510 and 525 nm for green, 610 nm for red and 450 nm for blue.

The last problem is pixel addressing, because, as we have already seen, in order to get the desired hue, you need to change the color intensity independently for each of the three sub-pixels. On a 1280×768 pixel plasma panel, there are approximately three million sub-pixels, resulting in six million electrodes. As you understand, laying six million tracks for independent control of sub-pixels is impossible, so the tracks must be multiplexed. The front tracks are usually built in solid lines, and the back tracks are in columns. The electronics built into the plasma panel, using a matrix of tracks, selects the pixel that needs to be lit on the panel. The operation is very fast, so the user does not notice anything - similar to beam scanning on CRT monitors.

In LCD panels, the principle of image formation is fundamentally different - there the light source is behind the matrix, and filters are used to separate colors into RGB.

Why are plasma panels better?

Secondly, the plasma panel is extremely versatile and allows you to use it not only as a TV, but also as a personal computer display with a large screen size. To do this, all models of plasma panels, in addition to the video input (as a rule, this is a regular AV input and S-VHS input), are also equipped with a VGA input. Therefore, such a panel will be indispensable when making presentations, as well as when used as a multifunctional information board when connected to the output of a personal computer or laptop. Well, fans of home multimedia and computer games will be just delighted: just imagine how much more advantageous it will look compared to a 17″ monitor on a 42″ screen, for example, the cockpit of a space starship or a virtual battlefield with space aliens!

Thirdly, the “picture” of a plasma panel is very similar in nature to the image in a “real” cinema. With this "cinematic" emphasis, plasma was immediately loved by "home cinema" fans and firmly established as the N1 candidate as a high-quality display medium in high-end home theaters. Moreover, the screen size of 42″ in most cases is quite enough. Obviously with a “cinema” application in mind, most plasma displays come in 16:9 aspect ratio, which has become the de-facto standard for home theater systems.

Fourth, with such a solid screen, plasma panels have extremely compact dimensions and dimensions. The thickness of the panel with a screen size of 1 meter does not exceed 9-12 cm, and the weight is only 28-30 kg. According to these parameters, today no other type of display means can compete with plasma at least some. Suffice it to say that a color kinescope with a comparable screen size has a depth of 70 cm and weighs more than 120-150 kg! Projection rear projection TVs are also not particularly slim, and front projection TVs tend to have low image brightness. The lighting parameters of plasma PDP panels are extremely high: the image brightness is over 700 cd/m 2 with a contrast ratio of at least 500:1. And what is very important, a normal image is provided in an extremely wide horizontal angle of view: 160°. That is, already today, PDPs have reached the level of the most advanced quality levels achieved by kinescopes over 100 years of their evolution. But large-screen plasma panels have been mass-produced for less than 5 years, and they are at the very beginning of their technological development.

Fifth, plasma panels are extremely reliable. According to Fujitsu, their technical resource is at least 60,000 hours (a very good kinescope has 15,000-20,000 hours), and the rejection rate does not exceed 0.2%. That is, an order of magnitude smaller than the 1.5-2% generally accepted for color CRT TVs.

At sixth, PDPs are virtually unaffected by strong magnetic and electric fields. This allows, for example, to use them in a home theater system in conjunction with speakers with unshielded magnets. This can sometimes be important, because unlike theater speakers, many “regular” HI-FI speakers come with an unshielded magnetic circuit. In a traditional TV-based home theater, using these speakers as front speakers is very difficult due to their strong influence on the TV's kinescope. And in a PDP-based AV system, as many as you like.

Seventh, due to their shallow depth and relatively small mass, plasma panels can be easily placed in any interior and even hung on the wall in a convenient place. With another type of display, such a focus is unlikely to succeed.

Other advantages of the plasma panel

Large diagonal. It is very expensive to produce LCD matrices of large diagonals and therefore economically unprofitable. With plasma panels, everything is exactly the opposite.
Panel does not flicker. It does not flicker, which means it does not tire the eyes, unlike conventional CRT TVs with a refresh rate of 50 Hz.
Best Color Reproduction. Modern plasma TVs are capable of displaying up to 29 billion colors. This is rightfully considered one of the main advantages of plasma.
Large viewing angles. The cells of the plasma panel glow by themselves, they do not need any "shutters", as in LCD panels, which regulate the amount of transmitted light. Therefore, the viewing angle of the plasma panel is almost 180 degrees in all directions.
Response time. The response time of a plasma panel is similar to a CRT, that is, much less than that of any LCD TV.
Brightness and Contrast. The contrast of plasma panels is much higher than that of LCD TVs. In a modern panel, it can reach 10,000:1. And the brightness of plasmas is absolutely uniform, since there is no backlight in the traditional sense.
Compact dimensions. The average plasma panel is no thicker than 10 cm. It can be easily screwed to the wall by ordering a special bracket.

A spoon of tar

afterglow. The afterglow effect is typical only for plasma panels. This is because regularly activated gas emits more UV light. The unevenness of the brightness level occurs when the operating time of different cells from the moment of switching on is very different from each other. Simply put, if you watch the same channel for a long time, then its sign will appear on the screen for some time after switching the channel. Panel manufacturers do their best to overcome this shortcoming by using screen servers and other more sophisticated technologies.
Phosphor degradation. This is the same process that can be observed in conventional CRT televisions. The panel lifetime is calculated up to the loss of half the screen brightness. For the latest generation plasma, this is approximately 60,000 hours.
Grain. Cheap non-HD plasma TVs suffer the most from this effect. Pay attention to it when choosing a budget model, and if it suddenly becomes annoying, postpone the purchase until you can purchase a model of a higher class.
Noisiness. Most plasmas produced today have cooling fans. Keep this in mind and be sure to listen to how much noise the panel makes before buying.

Thus, the only serious drawback of plasma panels today, by and large, is only their high price. However, compared with the cost of other display devices with the same screen size, their relative price in terms of 1 cm (or inch) of the image diagonal is not so large.

Analysis of characteristics

The principle of further narration will be as follows: we will take a typical plate specifications plasma panel and go through those lines that are worth paying attention to. So:

Diagonal, resolution

The diagonals of plasma panels start at 32 inches and end at 103 inches. Of this entire range, as mentioned above, 42-inch panels with a resolution of 853 × 480 pixels are the best sold in Russia so far. This resolution is called EDTV (Extended Definition Television) and means "high-definition television". Such a TV will be enough for a comfortable pastime, since in Russia there is no free high-definition television (High Definition TV - HDTV) yet. However, HDTVs tend to be more technically advanced, process the signal better, and are even capable of "pulling" it up to HDTV levels. It turns out, of course, not very much, but these attempts are valuable in themselves. In addition, you can already buy films recorded in HD DVD format in stores.

When buying an HDTV TV, pay attention to the supported signal format. The most common is 1080i, that is, 1080 interlaced lines. Interlacing is considered to be not very good, since there will be visible teeth on the edges of objects, but this disadvantage is leveled by high resolution. Support for the more advanced 1080p progressive scan format is currently found only on very expensive TVs of the latest, ninth generation. There is also an alternative 1080i format - this is 720p with a lower resolution, but with progressive scan. It will be difficult to tell the difference between the two pictures by eye, so ceteris paribus 1080i is preferable. However, a large number of TVs simultaneously support both 720p and 1080i, so in this regard, you should not have any problems with the choice.

Let's say a few words about various technologies image enhancement. Technologically, it so happened that the quality of the panel picture to a large extent depends on various software tricks. Each manufacturer has its own, and it happens that only their competent functioning determines all the differences visible to the eye in the picture between two TVs different brands, but one cost. However, it’s still not worth choosing a TV by the number of these technologies - it’s better to peer at the quality of their work, since you can admire plasmas in any normal video equipment store for as long as you like.

When choosing a diagonal, first of all, keep in mind - the larger it is, the farther from the TV you need to sit. In the case of a 42-inch panel, your favorite sofa should be at least three meters away from it. You can, of course, sit closer, but the image formation features on the panel will surely annoy you and interfere with viewing.

Aspect Ratio

All plasma TVs have panels with . A standard 4:3 TV picture will look fine on such a screen, just the unused screen area on the sides of the picture will be filled with black. Or gray if the TV allows you to change the fill color. The TV may try to stretch the image to fill the screen, but the result of this operation, as a rule, looks sad. In some plasma stores, they “broadcast” in this mode - apparently, the staff is just too lazy to look in the menu for a checkmark to turn off the scaling function. In Russia has already begun. By default, this aspect ratio is used only in HDTV.

Brightness

There are two brightness-related panel characteristics, panel brightness and overall TV brightness. The brightness of the panel cannot be judged on the finished product, because there is always a light filter in front of it. The brightness of the TV is the apparent brightness of the screen after the light passes through the filter. The actual brightness of the TV never exceeds half the brightness of the panel. However, the specifications of the TV indicate the original brightness, which you will never see. This is the first marketing gimmick.

Another feature of the numbers indicated in the specifications is related to the method of obtaining them. In order to protect the panel, its brightness per dot is reduced in proportion to the increase in the total area of illumination. That is, if you see a brightness value of 3000 cd / m2 in the characteristics, you should know that it is obtained only with a small illumination, for example, when several white letters are displayed on a black background. If we invert this picture, we will get, for example, 300 cd/m2.

Contrast

Two characteristics are also associated with this indicator: contrast in the absence of ambient light and in the presence of it. The value given in most specifications is the contrast measured in a dark room. Thus, depending on the lighting, the contrast can drop from 3000:1 to 100:1.

Interface connectors

The vast majority of plasma TVs have at least SCART, VGA, S-Video, a component video interface, as well as conventional analog audio inputs and outputs. Consider these and other connectors in more detail:

SCART- the number of these connectors can be up to three. At one time they were considered the most advanced, until HDMI appeared. SCART transmits analog video and stereo audio simultaneously.
HDMI- some might call it the evolutionary successor to SCART. Through HDMI, you can transmit an HD signal in 1080p resolution along with eight-channel audio. Due to the outstanding bandwidth and miniaturization of the connector, the HDMI interface is already supported by some camcorders and DVD players. And Panasonic supplies with its plasmas a remote control with the HDAVI Control function, which allows you to control not only the TV, but also other equipment connected to it via HDMI.
VGA- This is a common computer analog connector. Through it, you can connect a computer to the plasma.
DVI-I- a digital interface for connecting the same computer. However, there is another technique that works through DVI-I.
S-video- most often used to connect DVD players, game consoles and, in rare cases, a computer. Provides good image quality.
Component video interface- an interface for transmitting an analog signal, when each of its components goes through a separate cable. Thanks to this, the component signal is the highest quality of all analog signals. For sound transmission, similar RCA connectors and cables are used - each channel “runs” along its own wire.
Composite video interface(on one RCA connector) - as opposed to component, it provides the worst quality of signal transmission. One cable is used and, as a result, loss of color and clarity of the image is possible.

Acoustic system

Don't be under the illusion that low-power speakers built into your TV can sound good. Even if the manufacturer swears by the implementation of numerous "improving" technologies, the plasma will sound at a level sufficient only for watching the news. However, some of the most honest manufacturers do not even focus on the presence of speakers - yes, they are, but nothing more. Only external and not the cheapest speaker systems will allow you to enjoy real sound.

power usage

The power consumption of the Plasma TV varies depending on the picture being displayed. So don't be alarmed if you are told that a modest 42-inch panel "eats" 360 watts. The level indicated in the specification reflects the maximum value. With a completely white screen, the plasma panel will already consume 280 watts, and with a completely black screen - 160 watts.

Finally

In conclusion, I would like to give a couple of tips. The most important thing is to carefully check the panel for the presence of “broken” pixels, or rather, dots that are constantly lit in the same color. In case of detection - demand a replacement, since this is considered an unacceptable marriage, regardless of the number of such pixels. Do not let an unscrupulous seller fool you - up to five "broken" pixels are formally acceptable only for LCD panels, and even then not of the highest class. And keep in mind that some TV models come with a floor stand, that is, a bedside table. This kit will be more expensive, but the stand will be in perfect harmony with the TV and provide it with good stability.