Plasma displays. How a plasma panel works and works Man in three-dimensional space
On the front side of the screen and with address electrodes running along its back side. The gas discharge produces ultraviolet radiation, which in turn initiates the visible glow of the phosphor. In color plasma panels, each pixel of the screen consists of three identical microscopic cavities containing an inert gas (xenon) and having two electrodes, front and back. Once a strong voltage is applied to the electrodes, the plasma will begin to move. At the same time, it emits ultraviolet light, which hits the phosphors in the lower part 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 quite problematic. The first difficulty is the pixel size. A plasma panel's sub-pixel has a volume of 200 µm x 200 µm x 100 µm, and several million pixels need to be stacked on the panel, one to one. Secondly, the front electrode should be as transparent as possible. Indium tin oxide is used for this purpose because it is conductive and transparent. Unfortunately, plasma panels can be so large and the oxide layer so thin that when large currents flow across the resistance of the conductors there will be a voltage drop that 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 required 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 wavelengths between 510 and 525 nm for green, 610 nm for red and 450 nm for blue. The last problem remains the addressing of pixels, since, as we have already seen, in order to obtain the required shade, you need to change the color intensity independently for each of the three sub-pixels. On a 1280x768 pixel plasma panel there are approximately three million sub-pixels, resulting in six million electrodes. As you can imagine, laying out six million tracks to control the sub-pixels independently is not possible, so the tracks must be multiplexed. The front tracks are usually lined up in solid lines, and the back tracks 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 occurs very quickly, so the user does not notice anything - similar to beam scanning on CRT monitors.
A little history.
The first plasma display prototype appeared in 1964. It was designed by University of Illinois scientists Bitzer and Slottow as an alternative to the CRT screen for the Plato computer system. This display was monochrome, did not require additional memory or complex electronic circuits, and was highly reliable. Its purpose was mainly to display letters and numbers. However, it never had time to be realized as a computer monitor, since thanks to semiconductor memory, which appeared in the late 70s, CRT monitors turned out to be cheaper to produce. But plasma panels, due to their shallow body depth and large screen, have become widespread as information boards at airports, train stations and stock exchanges. IBM was heavily involved in information panels, and in 1987, Bitzer's former student, Dr. Larry Weber, founded the company Plasmaco, which began producing monochrome plasma displays. The first 21" color plasma display was introduced by Fujitsu in 1992. It was developed jointly with the design bureau of the University of Illinois and NHK. And in 1996, Fujitsu bought the Plasmaco company with all its technologies and plant, and launched the first commercially successful plasma panel on the market – Plasmavision with a 42" diagonal 852 x 480 resolution screen with progressive scan. The sale of licenses to other manufacturers began, the first of which was Pioneer. Subsequently, actively developing plasma technology, Pioneer, perhaps more than anyone else, succeeded in the plasma field, creating a number of excellent plasma models.
With all the stunning commercial success of plasma panels, the image quality at first was, to put it mildly, depressing. They cost incredible amounts of money, but quickly won an audience due to the fact that they differed favorably from CRT monsters with a flat body, which made it possible to hang the TV on the wall, and screen sizes: 42 inches diagonally versus 32 (maximum for CRT TVs). What was the main defect of the first plasma monitors? The fact is that, despite all the colorfulness of the picture, they were completely unable to cope with smooth color and brightness transitions: the latter disintegrated into steps with torn edges, which looked doubly terrible in a moving image. One could only guess why this effect arose, about which, as if by agreement, not a word was written by the media, which praised the new flat displays. However, after five years, when several generations of plasma had changed, steps began to appear less and less often, and in other indicators the image quality began to increase rapidly. In addition, in addition to 42-inch panels, 50" and 61" panels appeared. The resolution gradually increased, and somewhere during the transition to 1024 x 720, plasma displays were, as they say, in their prime. More recently, plasma has successfully crossed a new threshold of quality, entering the privileged circle of Full HD devices. Currently, the most popular screen sizes are 42 and 50 inches diagonally. In addition to the standard 61", a size of 65" has appeared, as well as a record 103". However, the real record is only to come: Matsushita (Panasonic) recently announced a 150" panel! But this, like the 103" models (by the way, the famous American company Runco produces plasma based on Panasonic panels of the same size), is an unbearable thing, both in the literal and even more literal sense (weight, price).
Plasma panel technologies.
Just something complicated.
Weight was mentioned for a reason: plasma panels weigh a lot, especially large models. This is due to the fact that the plasma panel is mainly made of glass, apart from the metal chassis and plastic body. Glass is necessary and irreplaceable here: it stops harmful ultraviolet radiation. For the same reason, no one produces fluorescent lamps from plastic, only from glass.
The entire design of a plasma screen is two sheets of glass, between which there is a cellular structure of pixels consisting of triads of subpixels - red, green and blue. The cells are filled with inert, so-called. “noble” gases - a mixture of neon, xenon, argon. An electric current passing through the gas causes it to glow. Essentially, 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 electrical discharge ionizes gases, turning them into plasma - that is, an electrically neutral, highly ionized substance consisting of electrons, ions and neutral particles. In fact, each pixel is divided into three subpixels containing red (R), green (G) or blue (B) phosphor: Green: Zn2SiO4:Mn2+ / BaAl12O19:Mn2+ Red: Y2O3:Eu3+ / Y0.65Gd0.35BO3:Eu3 Blue : BaMgAl10O17:Eu2+ These three phosphors produce light with wavelengths between 510 and 525 nm for green, 610 nm for red and 450 nm for blue. In fact, the vertical rows R, G and B are simply divided into separate cells by horizontal constrictions, which makes the screen structure very similar to the mask kinescope of a regular TV. The similarity with the latter is that it uses the same colored phosphorus that coats the subpixel cells from the inside. Only the phosphorus phosphor is ignited not by an electron beam, as in a kinescope, but by ultraviolet radiation. To create a variety of color shades, the light intensity of each subpixel is controlled independently. In CRT 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.
How light is produced. The basis of each plasma panel is plasma itself, 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 without a charge.
If you introduce a large number of free electrons into a 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 move towards each other.
Amid all this chaos, particles are constantly colliding. The collisions 'excite' the gas atoms in the plasma, causing them to release energy in the form of photons in the ultraviolet spectrum.
When photons hit the phosphor, the particles of the latter become excited and emit their own photons, but they will already be visible and take the form of light rays.
Between the glass walls are hundreds of thousands of cells coated with a phosphor that glows in red, green and blue. Beneath the visible glass surface - all along the screen - are long, transparent display electrodes, insulated on top with a sheet of dielectric and below with a layer of magnesium oxide (MgO).
For the process to be stable and controllable, it is necessary to provide a sufficient number of free electrons in the gas column plus a sufficiently high voltage (about 200 V), which will force the ion and electron flows to move towards each other.
And for ionization to occur instantly, in addition to control pulses, there is a residual charge on the electrodes. Control signals are supplied to the electrodes via horizontal and vertical conductors, forming an address grid. Moreover, the vertical (display) conductors are conductive paths on the inner surface of the protective glass from the front side. They are transparent (a layer of tin oxide mixed with indium). Horizontal (address) metal conductors are located on the back side of the cells.
Current flows from the display electrodes (cathodes) to the anode plates, which are rotated at 90 degrees relative to the display electrodes. The protective layer serves to prevent direct contact with the anode.
Under the display electrodes are the already mentioned RGB pixel cells, made in the form of tiny boxes, coated on the inside with a colored phosphor (each “color” box - red, green or blue - is called a subpixel). Below the cells is a structure of address electrodes positioned at 90 degrees to the display electrodes and passing through the corresponding color subpixels. Next is a protective level for the address electrodes, covered by the rear glass.
Before the plasma display is sealed, a mixture of two inert gases - xenon and neon - is injected into the space between the cells under low pressure. To ionize a specific cell, a voltage difference is created between the display and address electrodes located opposite each other above and below the cell.
A little reality.
In fact, the structure of real plasma screens is much more complex, and the physics of the process is not at all so simple. In addition to the matrix grid described above, there is another type - co-parallel, which provides an additional horizontal conductor. In addition, the thinnest metal tracks are duplicated to equalize the potential of the latter along the entire length, which is quite significant (1 m or more). The surface of the electrodes is covered with a layer of magnesium oxide, which performs an insulating function and at the same time provides secondary emission when bombarded with positive gas ions. There are also different types of pixel row geometry: simple and “waffle” (cells are separated by double vertical walls and horizontal bridges). Transparent electrodes can be made in the form of a double T or a meander, when they seem to be intertwined with the address electrodes, although they are in different planes. There are many other technological tricks aimed at increasing the efficiency of plasma screens, which was initially quite low. For the same purpose, manufacturers vary the gas composition of the cells, in particular, they increase the percentage of xenon from 2 to 10%. By the way, the gas mixture in the ionized state glows slightly on its own, therefore, in order to eliminate contamination of the spectrum of the phosphors by this glow, miniature light filters are installed in each cell.
Signal control.
The last problem remains the addressing of pixels, since, as we have already seen, in order to obtain the required shade, you need to change the color intensity independently for each of the three subpixels. On a 1280x768 pixel plasma panel there are approximately three million subpixels, resulting in six million electrodes. As you can imagine, laying out six million tracks to control the subpixels independently is not possible, so the tracks must be multiplexed. The front tracks are usually lined up in solid lines, and the back tracks 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 occurs very quickly, so the user does not notice anything - similar to beam scanning on CRT monitors. Pixels are controlled using three types of pulses: starting, supporting and damping. The frequency is about 100 kHz, although there are ideas for additional modulation of control pulses with radio frequencies (40 MHz), which will ensure a more uniform discharge density in the gas column.
In fact, the control of pixel lighting is in the nature of discrete pulse-width modulation: the pixels glow exactly as long as the supporting pulse lasts. Its duration with 8-bit encoding can take 128 discrete values, respectively, the same number of gradations of brightness is obtained. Could this be the reason for the ragged gradients breaking up into steps? Plasma of later generations gradually increased its resolution: 10, 12, 14 bits. The latest Runco models in the Full HD category use 16-bit signal processing (probably encoding as well). One way or another, the steps have disappeared and, hopefully, will not appear again.
In addition to the panel itself.
Not only the panel itself was gradually improved, but also signal processing algorithms: scaling, progressive conversion, motion compensation, noise suppression, color synthesis optimization, etc. Each plasma manufacturer has its own set of technologies, partially duplicating others under other names, but partially their own. Thus, almost everyone used Faroudja's DCDi scaling and adaptive progressive conversion algorithms, while some ordered original developments (for example, Vivix from Runco, Advanced Video Movement from Fujitsu, Dynamic HD Converter from Pioneer, etc.). In order to increase contrast, adjustments were made to the structure of control pulses and voltages. To increase brightness, additional jumpers were introduced into the shape of the cells to increase the surface covered with phosphor and reduce the illumination of neighboring pixels (Pioneer). The role of “intelligent” processing algorithms gradually grew: frame-by-frame optimization of brightness, a dynamic contrast system, and advanced color synthesis technologies were introduced. Adjustments to the original signal were made not only based on the characteristics of the signal itself (how dark or light the current scene was or how fast objects were moving), but also on the level of ambient light, which was monitored using a built-in photosensor. With the help of advanced processing algorithms, fantastic success has been achieved. Thus, Fujitsu, through an interpolation algorithm and corresponding modifications to the modulation process, has achieved an increase in the number of color gradations in dark fragments to 1019, which far exceeds the screen’s own capabilities with the traditional approach and corresponds to the sensitivity of the human visual system (Low Brightness Multi Gradation Processing technology). The same company developed a method of separate modulation of even and odd control horizontal electrodes (ALIS), which was then used in models from Hitachi, Loewe, etc. The method gave increased clarity and reduced jaggedness of inclined contours even without additional processing, and therefore, in the specifications of those using his plasma models had an unusual resolution of 1024 × 1024. This resolution, of course, was virtual, but the effect turned out to be very impressive.
Advantages and disadvantages.
Plasma is a display that, like a CRT TV, does not use light valves, but emits already modulated light directly by phosphorus triads. This, to a certain extent, makes plasma similar to cathode ray tubes, which are so familiar and have proven their worth over several decades.
Plasma has a noticeably wider coverage of the color space, which is also explained by the specifics of color synthesis, which is formed by “active” phosphorus elements, and not by passing the light flux of the lamp through light filters and light valves.
In addition, the plasma resource is about 60,000 hours.
So, plasma TVs are:
Large screen size + compactness + no flickering element; - High definition image; - Flat screen without geometric distortion; - Viewing angle 160 degrees in all directions; - The mechanism is not affected by magnetic fields; - High resolution and brightness of the image; - Availability of computer inputs; - 16:9 frame format and progressive scan mode.
Depending on the rhythm of the pulsating current that is passed through the cells, the intensity of the glow of each subpixel, which was controlled independently, will be different. By increasing or decreasing the intensity of the glow, you can create a variety of color shades. Thanks to this principle of operation of the plasma panel, it is possible to obtain high image quality without color and geometric distortions. The weak point is the relatively low contrast. This is due to the fact that the cells must be constantly supplied with low voltage current. Otherwise, the response time of the pixels (their lighting and fading) will be increased, which is unacceptable.
Now about the disadvantages.
The front electrode should be as transparent as possible. Indium tin oxide is used for this purpose because it is conductive and transparent. Unfortunately, plasma panels can be so large and the oxide layer so thin that when large currents flow across the resistance of the conductors there will be a voltage drop that 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. Plasma is afraid of not very delicate transportation. Electricity consumption is quite significant, although in recent generations it has been significantly reduced, at the same time eliminating noisy cooling fans.
Nowadays, almost everyone makes a choice in favor of flat panel TVs. Bulk units that take up half a room are definitely a thing of the past. Flat-screen TVs today are produced using two main technologies: plasma and liquid crystal.
Let's try to figure it out constructively: plasma or LCD, which is better? Let's put the debate on a scientific basis.
Today, plasma and liquid crystals are approaching each other in their main characteristics. If previously the difference between them was quite noticeable, now LCD is acquiring a larger diagonal, and plasma is increasing it. So which is better? What to choose for purchase?
LCD and plasma difference
LCD TV
LCD monitors are based on the following operating principle. Molecules under the influence of electric current move in space. Light, passing through a layer of crystals or being delayed by them, enters the light filter. The result is pixels consisting of three sub-pixels: green, blue and red. This combination of pixels is capable of creating a picture on the screen in the form we are familiar with.
TV based on a plasma panel
Plasma TVs work on the following principle. All pixels consist of micro-lamps with gas (neon and xenon). They are also three colors (red, green, blue). The cones containing the gas are connected to electrodes that supply voltage. The voltage level determines the brightness of the lamps. The plasma image is obtained due to the difference in the degree of illumination of the screen, which creates the shades perceived by the eye.
main parameters
Plasma or LCD which is better?
1. Screen sizes.
Plasma screens are never smaller than 32 inches. The minimum size of an LCD monitor can be comparable to the screen of a wristwatch. At the same time, today LCD panels are already produced in very large sizes, which are practically not inferior to plasma. Therefore, here you need to choose based on the dimensions of the room in which you plan to install the TV. Perhaps LCD is more universal in this regard.
2. Viewing angle
The viewing angle of the plasma is at least 170 degrees. LCD panels are, of course, inferior in this indicator. New LCD models are already approaching plasma in terms of angle rotation, but the larger the angle, the less contrast the image turns out to be. Therefore, the benefits of plasma need to be recognized here.
3. Pixel response speed.
Here, in terms of general parameters, plasma is the leader, in which gas discharges act almost instantly. Crystals move more slowly. However, in the latest LCD models, the turn-on time has been reduced to 1 millisecond, which has led to the virtual elimination of image blur.
4. Picture contrast.
Plasma screens produce images with greater contrast than LCD monitors. Plasma is characterized by direct radiation, resulting in a rich and bright image. The LCD matrix can simulate light from lamps, but does not emit it. Therefore, the LCD screen image is softer. This is a matter of consumer taste.
5. Panel illumination uniformity.
Plasma screens are illuminated evenly due to the uniformity of all screen cells. In LCDs, this effect is more difficult to achieve due to the quality of the backlights. In addition, with higher brightness, LCD monitors lose contrast. The advantage lies with plasma.
6.Energy consumption.
Plasma consumes twice as much energy as an LCD TV. This is due to the problem of heat dissipation, which requires additional fan operation. In this regard, LCD is much more profitable for the consumer.
7. Life time.
Plasma is designed for an average of 30 thousand hours, LCD for about 60 thousand. Some manufacturers offer models with operating capabilities of up to 100 thousand hours.
Results: Plasma or LCD which is better?
Plasma wins in most respects: it is safe for health, the image does not flicker, the brightness and contrast are high, and there is a wide viewing angle. The obvious disadvantage is high energy consumption. LCD panels are more economically profitable because they save energy. In addition, they are designed for a much longer service life and are cheaper to replace parts.
By and large, now both technologies are so developed that they are practically not inferior to each other in quality. It’s difficult to say unequivocally: plasma or LCD which is better. The choice depends on the specific needs of the consumer and subjective preferences.
Plasma Display Panel (PDP)
Just fifteen to 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 become reality, and anyone can buy such a screen.
The device of plasma panels
The principle of operation of a plasma panel is based on the glow of special phosphors when exposed to ultraviolet radiation. In turn, this radiation occurs during an electrical discharge in a highly rarefied gas environment. With such a discharge, a conducting “cord” is formed between the electrodes with a control voltage, consisting of ionized gas molecules (plasma). That’s why gas-discharge panels operating on this principle are called “ gas-discharge” or, which is the same thing – “ plasma” panels.
Design
A plasma panel is a matrix of gas-filled cells enclosed between two parallel glass surfaces. The gas medium is usually neon or xenon.
The gas discharge flows between the transparent electrode on the front side of the screen and the address electrodes running along its back side. The gas discharge produces ultraviolet radiation, which in turn initiates the visible glow of the phosphor.
In color plasma panels, each pixel of the screen consists of three identical microscopic cavities containing an inert gas (xenon) and having two electrodes, front and back. Once a strong voltage is applied to the electrodes, the plasma will begin to move. At the same time, it emits ultraviolet light, which hits the phosphors in the lower part 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 quite problematic.
The first difficulty is the pixel size. Sub-pixel A plasma panel has a volume of 200 µm x 200 µm x 100 µm, and several million pixels need to be laid out on the panel, one to one.
Secondly, the front electrode should be as transparent as possible. For this purpose it is used indium tin oxide, since it conducts current and is transparent. Unfortunately, plasma panels can be so large and the oxide layer so thin that when large currents flow across the resistance of the conductors there will be a voltage drop that 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 required 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 wavelengths between 510 and 525 nm for green, 610 nm for red and 450 nm for blue.
The last problem remains the addressing of pixels, since, as we have already seen, in order to obtain the required shade, you need to change the color intensity independently for each of the three sub-pixels. On a 1280x768 pixel plasma panel there are approximately three million sub-pixels, which gives a total of six million electrodes. As you can imagine, laying out six million tracks to control the sub-pixels independently is not possible, so the tracks must be multiplexed. The front tracks are usually lined up in solid lines, and the back tracks 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 occurs very quickly, 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 located behind the matrix, and filters are used to separate colors into RGB.
Why plasma panels are 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 a video input (usually a regular AV input and an 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 simply delighted: just imagine how much better the image of, for example, the cockpit of a spaceship or a virtual battlefield with space aliens will look compared to a 17″ monitor on a 42″ screen!
Third, the “picture” of a plasma panel is very similar in nature to the image in a “real” cinema. This cinematic emphasis made plasma an immediate favorite among home movie fans and firmly established itself as the N1 candidate for high-quality display in high-end home theaters. Moreover, a screen size of 42″ is quite sufficient in most cases. Obviously, with a view to “cinema” use, most plasma panels are produced with an image format of 16:9, which has become the de facto standard for home theater systems.
Fourth, with such a solid screen, plasma panels have extremely compact sizes and dimensions. The thickness of a 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 media can compete with plasma. 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 TVs with rear projection are also not particularly slender, and TVs with front projection, as a rule, have low image brightness. The lighting parameters of plasma PDP panels are exceptionally high: image brightness is over 700 cd/m2 with a contrast of at least 500:1. And what is very important, a normal image is provided in an extremely wide horizontal viewing angle: 160°. That is, today PDPs have reached the level of the most advanced quality levels achieved by picture tubes over 100 years of their evolution. But large-screen plasma panels have been in mass production for less than 5 years, and they are at the very beginning of their technological development.
Fifthly, plasma panels are extremely reliable. According to Fujitsu, their technical life is at least 60,000 hours (a very good kinescope has 15,000-20,000 hours), and the defect rate does not exceed 0.2%. That is, an order of magnitude less 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, their use in a home theater system in conjunction with speaker systems with unshielded magnets. Sometimes this can be important, since, unlike cinema acoustics, many “regular” HI-FI speakers are produced with an unshielded magnetic circuit. In a traditional TV-based home theater, it is very difficult to use these speakers as front speakers due to their strong influence on the TV's picture tube. And in a PDP-based AV system – as much as you want.
Seventh Due to their shallow depth and relatively light weight, 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 trick is unlikely to be possible.
Other advantages of a plasma panel
- Large diagonal. It is very expensive to produce LCD matrices with large diagonals and therefore not economically profitable. With plasma panels it’s exactly the opposite.
- The panel does not flicker. Does not flicker, which means it does not tire the eyes, unlike conventional CRT TVs with a refresh rate of 50 Hz.
- Best color rendition. 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 a plasma panel glow themselves; they do not need any “shutters”, as in LCD panels, to regulate the amount of light passing through. 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 faster 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 the 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
- Residual glow. The residual glow effect is typical only for plasma panels. This is because the regularly activated gas emits more ultraviolet light. Uneven brightness levels occur when the operating time of different cells from the moment they are turned on differs greatly from each other. To put it simply, if you watch the same channel for a long time, its sign will appear on the screen for some time after switching the channel. Panel manufacturers are doing their best to combat this drawback by using screenservers and other more sophisticated technologies.
- Phosphor degradation. This is the same process that can be observed in conventional CRT televisions. The panel's lifetime is calculated until half of the screen brightness is lost. For the latest generation plasma, this is approximately 60,000 hours.
- Grain. Cheap plasma TVs without HD support suffer from this effect the most. Pay attention to it when choosing a budget model, and if it suddenly irritates you, postpone the purchase until you can purchase a higher-class model.
- Noisiness. Most plasmas produced today have cooling fans. Keep this in mind and be sure to listen to how loud the panel is before purchasing.
Thus, the only serious drawback of plasma panels today is, by and large, their high price. However, compared to the cost of other information display devices with a similar screen size, their relative price per 1 cm (or inch) of image diagonal is not so large.
Analysis of characteristics
The principle of the further narration will be as follows: we will take a typical plate of the technical characteristics of a 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 still best sold in Russia. 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, HDTV TVs, as a rule, are technically more advanced, process the signal better and are even able to “pull it up” to the HDTV level. It turns out, of course, not very well, but these attempts are valuable in themselves. In addition, in stores you can already buy films recorded in HD DVD format.
When buying an HDTV TV, pay attention to the supported signal format. The most common is 1080i, that is, 1080 interlaced lines. Interlacing is generally considered not very good, since the jagged edges of objects will be noticeable, but this drawback is offset by the high resolution. Support for the more advanced 1080p format with progressive scan is so far found only on very expensive TVs of the latest, ninth generation. There is also an alternative format 1080i - this is 720p with a lower resolution, but with progressive scan. It will be difficult to detect the difference between the two images by eye, so all other things being equal, 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 image enhancement technologies. Technologically, it so happens that the picture quality of a panel depends to a large extent on various software tricks. Each manufacturer has their own, and it happens that only their proper functioning determines all the visible differences in the picture between two TVs of different brands, but of the same cost. However, it’s still not worth choosing a TV based on the number of these technologies - it’s better to look closely 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 you need to sit from the TV. 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 peculiarities of image formation on the panel will probably irritate you and interfere with your viewing.
Aspect Ratio
All plasma TVs have panels with . A standard 4:3 TV picture will look fine on such a screen, it’s just that the unused area of the screen on the sides of the image 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 entire screen, but the result of this operation usually looks sad. In some stores, plasmas are “broadcast” in exactly this mode - apparently, the staff is simply too lazy to look for a checkbox in the menu to disable the zoom function. It has already begun in Russia. By default, this aspect ratio is used only in HDTV.
Brightness
There are two panel specifications related to brightness: panel brightness and overall TV brightness. The brightness of the panel cannot be assessed on the finished product, because there is always a filter in front of it. TV brightness is the observed brightness of the screen after light passes through the filter. The actual brightness of the TV is never more than half the brightness of the panel. However, the TV specifications indicate the original brightness, which you will never see. This is the first marketing trick.
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 point decreases in proportion to the increase in the total illumination area. That is, if you see a brightness value of 3000 cd/m2 in the characteristics, you should know that it is obtained only with slight 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. Let's take a closer look at these and other connectors:
- SCART— the number of these connectors can reach three. At one time they were considered the most advanced, until HDMI appeared. SCART simultaneously transmits analog video and stereo audio.
- HDMI- some might call it an evolutionary successor to SCART. Via HDMI, you can transmit an HD signal in 1080p resolution along with eight-channel audio. Due to the outstanding bandwidth and miniature size 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 regular 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 also another technique that works via 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. To transmit sound, 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, a loss of color and image clarity 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 sound of the plasma will be at a level sufficient only for watching the news. However, some of the most honest manufacturers do not even focus the consumer’s attention on the presence of speakers - yes, they are there, but nothing more. Only external and not the cheapest speaker systems will allow you to enjoy real sound.
Energy consumption
The power consumption of a plasma TV varies depending on the picture being displayed. So don’t be alarmed if they tell you that a modest 42-inch panel “eats” 360 W. The level indicated in the specification reflects the maximum value. With a completely white screen, the plasma panel will consume 280 W, and with a completely black screen - 160 W.
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 constantly light up in one color. If found, request a replacement, as this is considered an unacceptable defect, regardless of the number of such pixels. Don’t let an unscrupulous seller fool you - up to five “dead” pixels are formally acceptable only for LCD panels, and even then not of the highest class. And also keep in mind that some TV models come with a floor stand, that is, a bedside table. This set will be more expensive, but the stand will be in perfect harmony with the TV and will provide it with good stability.
Overall material rating: 4.9
SIMILAR MATERIALS (BY TAG):
Father of the video Alexander Ponyatov and AMPEX
In plasma monitors (PDP - Plasma Display Panels), the image is formed by gas discharges in the panel pixels accompanied by the emission of light. Structurally, the panel consists of three glass plates, two of which are coated with thin transparent conductors: one plate is horizontal, the other is vertical. Between them there is a third plate, in which there are through holes at the intersection of the conductors of the first two plates; these are the pixels. When assembling the panel, these holes are filled with an inert gas: neon or argon. When a high-frequency voltage is applied to one of the vertically and one of the horizontally located conductors, a gas discharge occurs in the hole located at their intersection.
The gas discharge plasma emits light in the ultraviolet part of the spectrum, which causes phosphor particles to glow in the range visible to humans. In fact, every pixel on the screen works like a regular fluorescent lamp.
With a resolution of 512 x 512 pixel panel has dimensions of about 200 x 200 mm, with 1024 x 1024 pixels - 400 x 400; panel thickness is about 6-8 mm.
High brightness and contrast along with the absence of jitter are the big advantages of such monitors. In addition, the angle relative to the normal at which a good image can be seen on plasma monitors is significantly greater than 45° in the case of LCD monitors. The main disadvantages of this type of monitor are the rather high power consumption, which increases with increasing monitor diagonal, and low resolution due to the large size of the image element. In addition, the properties of the phosphor elements quickly deteriorate, and the screen becomes less bright, so the service life of plasma monitors is limited to 10,000 hours (this is about 5 years in office conditions). Due to these limitations, such monitors are currently used only for conferences, presentations, information boards, that is, where large screen sizes are required to display information. Currently, work is underway to create PALC (Plasma Addressed Liquid Crystal) technology, which promises to combine the advantages of plasma and LCD screens with an active matrix in order to effectively use PALC panels in computers.
End of work -
This topic belongs to the section:
Main computer blocks, their purpose and functional characteristics
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Lecture notes
from the discipline “Computer Architecture” for 2nd year students for specialty 6.0915.01 “Computer Computer Systems and Measurements” directly 0915 “Computer Engineer
Microprocessor
Microprocessor (MP) is the central device of a PC, designed to control the operation of all machine blocks and to perform arithmetic and logical operations on information.
Composed of m
System bus
The system bus is the main interface system of a computer, ensuring the interfacing and communication of all its devices with each other. The system bus includes: □ code data bus (CDB
Main memory
External memory
External memory refers to the external devices of a PC and is used for long-term storage of any information that may ever be required to solve problems. In particular, in external memory
External devices
External devices (ED) of a PC are the most important component of any computing complex; suffice it to say that the cost of external devices is up to 80-85% of the cost of the entire PC.
I provide VU PC
Additional integrated circuits
Along with standard external devices, some additional integrated circuits can be connected to the system bus and to the MP PC, expanding and improving the functionality of the micro
PC design elements
Structurally, PCs are made in the form of a central system unit, to which external devices are connected via connectors: additional memory units, keyboard, display, etc.
Functional characteristics of the computer
The main functional characteristics of a computer are: 1. Productivity, speed, clock frequency.
2. Bit capacity of the microprocessor and interface code buses.
Performance, speed, clock speed
The performance of modern computers is usually measured in millions of operations per second. The units of measurement are: □ MIPS (MIPS - Millions Instruction Per Second) - for operations
Microprocessor and interface code bus width
Bit capacity is the maximum number of bits of a binary number on which a machine operation can be simultaneously performed, including the operation of transmitting information; the higher the bit depth,
Type and capacity of RAM
The capacity (volume) of RAM is usually measured in megabytes. We remind you that 1 MB = 1024 KB = 10242 bytes.
Many modern application programs with RAM
Availability, types and capacity of cache memory
Cache memory is a buffer, non-user-accessible, high-speed memory that is automatically used by the computer to speed up operations with information stored in slower memory.
Self-test questions
1. Draw a block diagram of a personal computer.
Most modern PCs such as IBM PCs use CISC type MPs produced by many companies: Intel, AMD, Cyrix, IBM, etc. Intel is the “trend setter” here, but it is “on the heel”
Pentium microprocessors
Microprocessors 80586 (P5) are better known by their Pentium trademark, which is patented by Intel (MP 80586 from other companies have different designations: K5 from AMD, Ml from Cyrix, etc.). E
Pentium Pro microprocessors
In September 1995, the sixth generation MP 80686 (P6), branded as Pentium Pro, was released. The microprocessor consists of two crystals: the MP itself and cache memory. But it is not fully compatible with
Microprocessors Pentium MMX and Pentium II
In 1997, the Pentium and Pentium Pro microprocessors, upgraded to work in multimedia technology, appeared and received the trademarks, respectively, Pentium MMX (MMX - MultiMedia eXtent
Pentium III microprocessors
The Pentium III (Coppermine) processors, which appeared in 1999, are a further development of the Pentium II. Their main difference is the expansion set based on a new block of 128-bit registers
Pentium 4 microprocessors
A modification of the Pentium MP - Pentium 4 - is intended for high-performance computers, primarily servers, high-end workstations and multimedia gaming PCs. Let's look at the main
NT technology
Hyper Treading technology (tread - thread) implements multi-threaded execution of programs: on one physical processor you can simultaneously execute two tasks or two threads of commands of one program
RAID technology
Most new microprocessors support Intel RAID technology (Redundant Array Intensive Disk - an array of inexpensive redundant disks). The advantage of this technology is the simplicity of the organization
Intel's new MP marking
Since 2004, Intel has introduced new markings for its microprocessors. The single three-digit processor number introduced by the company will take into account several characteristics at once: the basic architecture
Over Drive Microprocessors
Of interest are the Over Drive MPs, which are essentially a kind of coprocessors that provide the 80486 MP with operating modes and efficient performance characteristic of the Pentium MP, and for
RISC microprocessors
Microprocessors of the RISC type contain only a set of simple instructions, most often found in programs. If it is necessary to execute more complex commands in the microprocessor, they are performed automatically
VLIW microprocessors
This is a relatively new and very promising type of MP. Microprocessors of the VLIW type were produced in 2004 by the following companies: □ Transmeta - this is a Crusoe microprocessor
Physical and functional structure of the microprocessor
The physical structure of a microprocessor is quite complex. The processor core contains the main control and execution modules - blocks for performing operations on integer data. To local controls
Control device
The control device (CU) is functionally the most complex PC device - it generates control signals that arrive via coded instruction buses (IBC) to all blocks of the machine. Simplified
Arithmetic logic unit
An arithmetic logic unit (ALU) is designed to perform arithmetic and logical information transformation operations. Functionally, in the simplest version of the ALU (Fig. 8.2) sos
Microprocessor memory
The microprocessor memory (MPM) of the basic MP 8088 includes 14 two-byte storage registers. MP 80286 and higher have additional registers, for example, MP type VLIW e
Universal registers
Registers AX, BX, CX and DX are universal (they are often called general purpose registers - RON); each of them can be used for temporary storage of any data, while allowing
Segment registers
Segment addressing registers CS, DS, SS, ES are used to store the starting addresses of memory fields (segments) allocated in programs for storing1: □ program commands
Offset registers
Shift registers (intra-segment addressing) IP, SP, BP, SI, DI are designed to store relative addresses of memory cells within segments (offsets relative to the beginning of segments): &n
Flag Register
The F flag register contains conditional single-digit mask signs, or flags, that control the passage of the program in the PC; flags work independently of each other, and only for convenience they are placed in a single
Many modern application programs with RAM
1. Give a brief description of the microprocessor, its structure, purpose, and main parameters.
2. Name and explain the main functions performed by a microprocessor.
3. Name
Motherboards
The system board (SB), or backplane, mother board (MB) is the most important part of the computer, containing its main electronic components
Types of motherboards
Microprocessors installed on the motherboard can be changed in a certain range of models, and the main non-replaceable functional component of the SP is a set of system microprocessors
Many modern application programs with RAM
1. Explain the role of the motherboard in a PC.
2. Name the main devices located on the PC motherboard.
3. Name the main formats of motherboards.
4. Give a brief
Computer interface systems
Interface is a set of interface and communication means that ensures effective interaction of systems or their parts.
(In computer literature, sometimes
Expansion buses
1. PC/XT bus - 8-bit data bus and 20-bit address bus, designed for a clock frequency of 4.77 MHz; has 4 lines for hardware interrupts and 4 channels for direct memory access (channel
Local buses
Modern computing systems are characterized by: □ rapid growth in the speed of microprocessors and some external devices □ the emergence of programs that require
Peripheral buses
Peripheral buses provide communication between the central devices of the machine and external devices (disk drives, keyboard, mouse, scanner, etc.). They are the external interfaces of E
Universal serial buses
In 2003-2004, revolutionary changes took place in computer interface systems: first there was a revolution towards serial interfaces, and in 2004 wireless systems began to actively develop
USB serial bus
The first and most common serial bus now is USB (Universal Serial Bus). It appeared in 1995 and was designed to replace such outdated
IEEE 1394 standard
IEEE 1394 (Institute of Electrical and Electronic Engineers 1394 standard) is a new and promising serial interface designed for
Serial SATA interface
Wireless interfaces are used to transmit data over distances from several tens of centimeters to several kilometers. They are most convenient for users,
IrDA interfaces
One of the first wireless interfaces to be used in computers was the IrDA standard, in which communication is carried out via an infrared radiation channel. Infrared range was used
Bluetooth interface
Bluetooth is a technology for transmitting data over radio channels in the frequency range of about 2.5 GHz over short distances, even in the absence of direct visibility between devices. Originally Bluetooth
WUSB interface
Intel, as the main replacement for Bluetooth, proposed a wireless version of the USB interface - the WUSB (Wireless USB) interface, which, according to its forecasts, should have supplanted the bluetooth by 2006.
WiFi Interface Family
WiFi interfaces refer to a group of interfaces that provide wireless access to networks for computers. The basic IEEE 802.11 or WiFi (Wireless Fidelity) standard was developed
WiMax interfaces
WiMax wireless technology is the commercial name for the IEEE 802.16a standard, announced in January 2003. This is the third version of the IEEE 802.16 standard, first proposed in December 2001.
Other interfaces
□ PCMCIA (Personal Computer Memory Card International Association - association of manufacturers of memory cards for personal computers) - external bus of laptop-class computers. Other names
Many modern application programs with RAM
1. What is an interface?
2. What functions does the interface perform?
3. Give a brief description of the ISA bus.
4. Give a brief description of the PCI interface family.
PC storage devices
Personal computers have four levels of memory: □ microprocessor memory (MPM);
□ register cache memory;
□ main memory (RAM);
Static and dynamic RAM
RAM can be composed of dynamic (Dynamic Random Access Memory - DRAM) or static (Static Random Access Memory - SRAM) type chips.
DIP (Dual In-line Package - a case with a double-row pinout arrangement) - a single memory chip, now used only as part of enlarged modules (as part of SIM modules
FPM DRAM
FPM DRAM (Fast Page Mode DRAM) - dynamic memory with fast page access, actively used with microprocessors 80386 and 80486. Page access memory is different
RAM EDO
RAM EDO (EDO - Extended Data Out, extended retention time (availability) of output data), in fact, are ordinary FPM chips, to which a set of registers has been added
BEDO DRAM
BEDO DRAM (Burst Extended Data Output, EDO with block access). Modern processors, thanks to internal and external caching of commands and data, communicate with the main memory
DDR SDRAM
DDR SDRAM(Double Data Rate SDRAM - SDRAM II). A variant of SDRAM memory that transfers information on both edges of the clock signal. This allows you to double your throughput
Read-only storage devices
Read-only memory (ROM, or ROM- Read Only Memory, read-only memory) is also built on the basis of modules (cassettes) installed on the motherboard and
Logical structure of main memory
Structurally, main memory consists of millions of individual single-byte memory cells. The total capacity of the main memory of modern PCs usually ranges from 16 to 512 MB. Capacity
External storage devices
External memory devices, or, otherwise, external storage devices (ESD), are very diverse. They can be classified according to a number of characteristics: by type of carrier, by type
Files, their types and organization
A file is a named collection of data on an external storage medium. In a PC, the concept of a file is applied mainly to data stored on disks (less often on cassette tape).
File management
Access is access to a file for the purpose of reading or writing information to it.
The file system supports two types of file access: □ sequential access method;
File attributes
An attribute is a file classifying feature that determines how it is used, access rights to it, etc. DOS allows the following elements to be specified in the attribute:
Logical organization of the file system
The ordering of files stored in disk memory is called logical file system organization. The basis of logical organization is directories. A directory is a special file in which
In order for the operating system to access the file, you must specify: □ disk;
□ catalogue;
□ full file name.
This information is available
Placing information on disks
Disc tracks are divided into sectors. One track sector typically holds 512 bytes of data. Data exchange between NMD and OP is carried out sequentially by clusters.
Addressing information on disk
The following systems for addressing information on the MD are used: □ in BIOS - three-dimensional: number of the cylinder (track), magnetic head (disk side), sector;
□ in DOS - after
Hard disk drives
Hard magnetic disk drives (HDD, hard drives, Hard Disk Drive - HDD) are devices designed for long-term storage of information. As a
Portable disk drives
Recently, portable drives (they are also called external, mobile, removable, and their portable versions are pocket HDDs) have become widespread. Power portable
Jaz 1Gb, Jaz 2Gb
Models Jaz 1Gb, Jaz 2Gb, developed by Iomega (Jaz 1Gb support hard drives with a capacity of 1 GB, and Jaz 2 Gb drives support drives with a capacity of 1 and 2 GB). Iomega Jaz 2Gb disk
ZIV1, ZIV2
ZIV is a very elegant miniature 2.5-inch form factor disk drive with a special controller that connects to USB 1.1 (ZIV1) or USB 2.0 (ZIV2) interfaces. Standard size
RAID disk arrays
Database server machines and supercomputers often use RAID (Redundant Array of Inexpensive Disks) disk arrays, in which several
Floppy disk drives
Floppy magnetic disk drives (Floppy Disk Drives, FDD) are devices designed for writing and reading information from floppy magnetic disks (Floppy Disk Drives, FDD)
Floppy disk drives
Floppy disk drives perform conventional magnetic recording of information, but with a significantly higher density of tracks on the disk surface. This density has reached
Optical drives
Introduced in 1982 by Philips and Sony, the optical compact disc revolutionized personal computing and the entertainment industry. Compact-d
Non-rewritable laser optical discs CD-ROM
CD-ROMs have become widespread. The CD is a plastic polycarbonate circle with a diameter of 4.72 inches (CDs with a diameter of 3.5, 5.25, 12 and 14 inches are found) and then
Write-once optical discs
CD-R drives allow you to write information once on disks with form factors of 4.72 and 3.5 inches. For recording, special blank discs are used, sometimes called blanks (target). On
Write-once optical discs
CD-RW drives allow you to repeatedly record information on discs with a reflective surface, under which is applied a layer of the Ag-In-Sb-Te type (containing silver, indium, antimony, tellurium) with a variable frequency
Digital DVDs
A real revolution in the technology of external storage devices is ready to be made by new digital video disks, which first appeared in 1996, having the dimensions of conventional CD-ROMs, but with a much larger capacity.
Magneto-optical disk drives
The operating principle of a magneto-optical storage device (Magneto Optical) is based on the use of two technologies - laser and magnetic. Information is recorded on magnetic media
Tape drives
Magnetic tape drives were the first storage devices in computers.
In universal computers, drives on reel-to-reel magnetic tape (NMR) were and are widely used, and in personal computers
Flash memory devices
Many modern application programs with RAM
Flash Disks are a very popular and very promising class of non-volatile storage devices. Flash drives (solid-state drives) are a modification of HDD and represent a
1. Give a classification of PC storage devices and give a brief description of the individual classes.
2. What is and where is static RAM and dynamic RAM used?
Video terminal devices
Video terminal devices are designed to quickly display text and graphic information for the purpose of visual perception by the user. The video terminal consists of
CRT-based video monitors
Monochrome monitors are significantly cheaper than color monitors, have a clearer image and higher resolution, can display dozens of shades of gray, and are less harmful to health.
Color monitors
A color CRT monitor uses three electron guns, as opposed to the single gun used in monochrome monitors. Each gun is responsible for one of three primary colors: red
Types of image scanning on the monitor
The scanning unit can supply voltages of different shapes to the deflection system of the monitor, which determines the type of image scanning. There are three types of scans: □ raster;
Digital and analogue monitors
Depending on the type of signal controlling the beam, monitors are either analog or digital.
In analog monitors, manual control is based on rotary potentiometers, in digital monitors -
Monitor screen size
Monitors are available with screens of different sizes.
The monitor screen size is usually determined by its diagonal in inches: for IBM PC-compatible PCs, screen sizes are 12, 14, 15,
Vertical (frame) scan
An important characteristic of a monitor is its frame rate. Changing images (frames) on the screen with a frequency of 25 Hz is perceived by the eye as continuous movement, but due to
Monitor resolution
Video monitors can usually operate in two modes: text and graphics.
In text mode, the image on the monitor screen consists of displayed extended ASCII characters, f
Frequency Bandwidth
The frequency bandwidth is of independent importance, since the clarity of the image on the screen depends on it (very often only this value is indicated on the monitor box).
Ergonomics of CRT monitors
The ergonomics of a monitor is determined by the successful selection of such characteristics as the quality of the picture on the screen, dimensions, weight, design of the monitor, and also, to a greater extent, its harmlessness
TSO-99 standard
The requirements that TCO-99 places on conventional cathode ray (CRT) monitors fall into 6 main categories. The first two combine properties that characterize the visual ergonomics of the app.
Monitors on liquid crystal displays (LCD, Liquid Crystal Display) are digital flat monitors.
These monitors use a special clear liquid that, when detected,
Electroluminescent monitors
Electroluminescent monitors (FED - Field Emission Display) use two thin glass plates with transparent wires applied to them as a panel. One of these plates is covered with
Light-emitting monitors
In light-emitting monitors (LEP - Light Emitting Polymer), a semiconductor polymer wafer is used as a panel, the elements of which begin to glow under the influence of electric current.
Stereo monitors
A second generation of monitors has also been developed that create three-dimensional three-dimensional images. To create a three-dimensional (3D), or rather stereoscopic image, it is necessary to show the left and right eyes
Video controllers
Many modern application programs with RAM
A video controller (video adapter) is an in-system device that converts data into a signal displayed by a monitor and directly controls the monitor and output
1. Give a multidimensional classification of monitors.
2. List and explain the main parameters taken into account when choosing a CRT monitor.
3. Explain the main factors influencing the
Keyboard
The keyboard is the most important device for the user, with the help of which data, commands and control actions are entered into the PC. The keys are marked with Latin and national letters.
Graphic mouse
We should briefly dwell on another type of device for manually entering information into a PC. We are talking about graphic manipulators, which use touch screens, tablets
Printers
Printing devices (printers) are devices for outputting data from a computer, converting ASCII codes and bit sequences into corresponding characters and recording
Dot matrix printers
In dot matrix printers, the image is formed from dots using the impact method, so it is more correct to call them impact-matrix printers, especially since other types of character-synthesizing printers
Inkjet printers
These are the most common printers currently used. Inkjet printers have thin tubes in the print head instead of needles - nozzles, through which tiny droplets are thrown onto the paper
Thermal printers belong to the group of matrix printers. They use a thermal matrix and special thermal paper or thermal carbon paper. The operating principle of a thermal printer is very simple. Seal
Solid ink printers
Solid ink technology was developed by Tektronix, part of the Xerox company. The dyes used in a solid ink printer are solid cubes of color
Service devices
High-speed printers, as already noted, have their own buffer memory, which is used both when exchanging data with a PC and for storing downloaded fonts. Memory for dot matrix printers is sky high
Network printers
A network printer is a printer that has an IP address and, thus, is a kind of website. Such a printer can be accessed via an IP address using a regular browser, and full information can be retrieved.
Scanners
A scanner is a device for entering information into a computer directly from a paper document. This can be texts, diagrams, drawings, graphs, photographs and other information. Scanner, p
Types of scanners
Hand-held scanners are the simplest in design - they consist of a line of LEDs and a light source placed in a single housing. Moving through the image of such a scanner
Vector
In a raster format, an image is stored in a file as a mosaic set of many dots corresponding to the pixels of the image displayed on the display screen. File created
Digitizers
A digitizer, or graphics tablet, is a device whose main purpose is to digitize images. It consists of two parts: the base
Main characteristics of digitizers
Digitizers are: □ electrostatic;
□ electromagnetic.
Electrostatic digitizers record a local change in electrostatic
Plotters
Plotters (plotter, plotter) are devices for outputting graphic information (drawings, diagrams, pictures, diagrams, etc.) from a computer onto paper or another type of media.
Many modern application programs with RAM
Types of plotters
Pen plotters are vector-type electromechanical devices in which an image is created by drawing lines using a writing element, generally called
The plasma panel is a bit like an ordinary picture tube - it is also coated with a composition that can glow. At the same time, like LCDs, they use a grid of electrodes coated with a protective coating of magnesium oxide to transmit a signal to each pixel cell. The cells are filled with intervening gases - a mixture of neon, xenon, and argon. An electric current passing through the gas causes it to glow.
Essentially, 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 electrical discharge ionizes gases, turning them into plasma - that is, an electrically neutral, highly ionized substance consisting of electrons, ions and neutral particles.
Under normal conditions, individual atoms of a gas contain an equal number of protons (particles with a positive charge in the nucleus of an atom) and electrons, and thus the gas is electrically neutral. But if you introduce a large number of free electrons 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 move towards each other. Amid all this chaos, particles are constantly colliding.
The collisions “excite” the gas atoms in the plasma, causing them to release energy in the form of photons.
In plasma panels Mostly inert gases are used - 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.
After the discharge, ultraviolet radiation causes 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 subpixels containing red, green or blue phosphorus. To create a variety of color shades, the light intensity of each subpixel is controlled independently. In CRT TVs this is done using a mask (and the spotlights are different for each color), and 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 the light source provides excellent vertical and horizontal viewing angles and excellent color reproduction (unlike, for example, LCDs, which require backlighting). However, conventional plasma displays normally suffer from low contrast. This is due to the need to constantly supply low-voltage current to all cells. Without this, the pixels will “turn on” and “off” like regular fluorescent lamps, that is, for a very long time, prohibitively increasing the response time. Thus, the pixels must remain on, emitting low-intensity light, which, of course, will affect the display's contrast.
At the end of the 90s. last century, Fujitsu managed to somewhat mitigate the problem by improving the contrast of its panels from 70:1 to 400:1.
By 2000, some manufacturers stated in panel specifications a contrast ratio of up to 3000:1, now it is already 10000:1+.
The manufacturing process for plasma displays is somewhat simpler than the LCD manufacturing process. Compared to the production of TFT LCD displays, which requires 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.
However, the age of plasma panels is short-lived - just recently the average panel life was 25,000 hours, now it has almost doubled, but this does not solve the problem. In terms of operating hours, a plasma display is more expensive than an LCD. For a large presentation screen, the difference is not very significant, however, if you equip numerous office computers with plasma monitors, the benefit of LCD becomes obvious to the purchasing company.
Another important disadvantage of “plasma” is the large pixel size. Most manufacturers are unable to create cells smaller than 0.3 mm - this is larger than the grain of a standard LCD matrix. It doesn't look like the situation will change for the better in the near future. In the medium term, such plasma displays will be suitable as home TVs and presentation screens up to 70+ inches in size. If “plasma” is not destroyed by LCD and new display technologies appearing every day, in some ten years it will be available to any buyer.
