gas plasma display screens brands

A plasma display panel (PDP) is a type of flat panel display that uses small cells containing plasma: ionized gas that responds to electric fields. Plasma televisions were the first large (over 32 inches diagonal) flat panel displays to be released to the public.

Until about 2007, plasma displays were commonly used in large televisions (30 inches (76 cm) and larger). By 2013, they had lost nearly all market share due to competition from low-cost LCDs and more expensive but high-contrast OLED flat-panel displays. Manufacturing of plasma displays for the United States retail market ended in 2014,

Plasma displays are bright (1,000 lux or higher for the display module), have a wide color gamut, and can be produced in fairly large sizes—up to 3.8 metres (150 in) diagonally. They had a very low luminance "dark-room" black level compared with the lighter grey of the unilluminated parts of an LCD screen. (As plasma panels are locally lit and do not require a back light, blacks are blacker on plasma and grayer on LCD"s.)LED-backlit LCD televisions have been developed to reduce this distinction. The display panel itself is about 6 cm (2.4 in) thick, generally allowing the device"s total thickness (including electronics) to be less than 10 cm (3.9 in). Power consumption varies greatly with picture content, with bright scenes drawing significantly more power than darker ones – this is also true for CRTs as well as modern LCDs where LED backlight brightness is adjusted dynamically. The plasma that illuminates the screen can reach a temperature of at least 1200 °C (2200 °F). Typical power consumption is 400 watts for a 127 cm (50 in) screen. Most screens are set to "vivid" mode by default in the factory (which maximizes the brightness and raises the contrast so the image on the screen looks good under the extremely bright lights that are common in big box stores), which draws at least twice the power (around 500–700 watts) of a "home" setting of less extreme brightness.

Plasma screens are made out of glass, which may result in glare on the screen from nearby light sources. Plasma display panels cannot be economically manufactured in screen sizes smaller than 82 centimetres (32 in).enhanced-definition televisions (EDTV) this small, even fewer have made 32 inch plasma HDTVs. With the trend toward large-screen television technology, the 32 inch screen size is rapidly disappearing. Though considered bulky and thick compared with their LCD counterparts, some sets such as Panasonic"s Z1 and Samsung"s B860 series are as slim as 2.5 cm (1 in) thick making them comparable to LCDs in this respect.

Wider viewing angles than those of LCD; images do not suffer from degradation at less than straight ahead angles like LCDs. LCDs using IPS technology have the widest angles, but they do not equal the range of plasma primarily due to "IPS glow", a generally whitish haze that appears due to the nature of the IPS pixel design.

Less visible motion blur, thanks in large part to very high refresh rates and a faster response time, contributing to superior performance when displaying content with significant amounts of rapid motion such as auto racing, hockey, baseball, etc.

Earlier generation displays were more susceptible to screen burn-in and image retention. Recent models have a pixel orbiter that moves the entire picture slower than is noticeable to the human eye, which reduces the effect of burn-in but does not prevent it.

Due to the bistable nature of the color and intensity generating method, some people will notice that plasma displays have a shimmering or flickering effect with a number of hues, intensities and dither patterns.

Earlier generation displays (circa 2006 and prior) had phosphors that lost luminosity over time, resulting in gradual decline of absolute image brightness. Newer models have advertised lifespans exceeding 100,000 hours (11 years), far longer than older CRTs.

Uses more electrical power, on average, than an LCD TV using a LED backlight. Older CCFL backlights for LCD panels used quite a bit more power, and older plasma TVs used quite a bit more power than recent models.

Fixed-pixel displays such as plasma TVs scale the video image of each incoming signal to the native resolution of the display panel. The most common native resolutions for plasma display panels are 852×480 (EDTV), 1,366×768 and 1920×1080 (HDTV). As a result, picture quality varies depending on the performance of the video scaling processor and the upscaling and downscaling algorithms used by each display manufacturer.

Early plasma televisions were enhanced-definition (ED) with a native resolution of 840×480 (discontinued) or 852×480 and down-scaled their incoming high-definition video signals to match their native display resolutions.

The following ED resolutions were common prior to the introduction of HD displays, but have long been phased out in favor of HD displays, as well as because the overall pixel count in ED displays is lower than the pixel count on SD PAL displays (852×480 vs 720×576, respectively).

Early high-definition (HD) plasma displays had a resolution of 1024x1024 and were alternate lighting of surfaces (ALiS) panels made by Fujitsu and Hitachi.

Later HDTV plasma televisions usually have a resolution of 1,024×768 found on many 42 inch plasma screens, 1280×768 and 1,366×768 found on 50 in, 60 in, and 65 in plasma screens, or 1920×1080 found on plasma screen sizes from 42 inch to 103 inch. These displays are usually progressive displays, with non-square pixels, and will up-scale and de-interlace their incoming standard-definition signals to match their native display resolutions. 1024×768 resolution requires that 720p content be downscaled in one direction and upscaled in the other.

Ionized gases such as the ones shown here are confined to millions of tiny individual compartments across the face of a plasma display, to collectively form a visual image.

A panel of a plasma display typically comprises millions of tiny compartments in between two panels of glass. These compartments, or "bulbs" or "cells", hold a mixture of noble gases and a minuscule amount of another gas (e.g., mercury vapor). Just as in the fluorescent lamps over an office desk, when a high voltage is applied across the cell, the gas in the cells forms a plasma. With flow of electricity (electrons), some of the electrons strike mercury particles as the electrons move through the plasma, momentarily increasing the energy level of the atom until the excess energy is shed. Mercury sheds the energy as ultraviolet (UV) photons. The UV photons then strike phosphor that is painted on the inside of the cell. When the UV photon strikes a phosphor molecule, it momentarily raises the energy level of an outer orbit electron in the phosphor molecule, moving the electron from a stable to an unstable state; the electron then sheds the excess energy as a photon at a lower energy level than UV light; the lower energy photons are mostly in the infrared range but about 40% are in the visible light range. Thus the input energy is converted to mostly infrared but also as visible light. The screen heats up to between 30 and 41 °C (86 and 106 °F) during operation. Depending on the phosphors used, different colors of visible light can be achieved. Each pixel in a plasma display is made up of three cells comprising the primary colors of visible light. Varying the voltage of the signals to the cells thus allows different perceived colors.

The long electrodes are stripes of electrically conducting material that also lies between the glass plates in front of and behind the cells. The "address electrodes" sit behind the cells, along the rear glass plate, and can be opaque. The transparent display electrodes are mounted in front of the cell, along the front glass plate. As can be seen in the illustration, the electrodes are covered by an insulating protective layer.

Control circuitry charges the electrodes that cross paths at a cell, creating a voltage difference between front and back. Some of the atoms in the gas of a cell then lose electrons and become ionized, which creates an electrically conducting plasma of atoms, free electrons, and ions. The collisions of the flowing electrons in the plasma with the inert gas atoms leads to light emission; such light-emitting plasmas are known as glow discharges.

Relative spectral power of red, green and blue phosphors of a common plasma display. The units of spectral power are simply raw sensor values (with a linear response at specific wavelengths).

In a monochrome plasma panel, the gas is mostly neon, and the color is the characteristic orange of a neon-filled lamp (or sign). Once a glow discharge has been initiated in a cell, it can be maintained by applying a low-level voltage between all the horizontal and vertical electrodes–even after the ionizing voltage is removed. To erase a cell all voltage is removed from a pair of electrodes. This type of panel has inherent memory. A small amount of nitrogen is added to the neon to increase hysteresis.phosphor. The ultraviolet photons emitted by the plasma excite these phosphors, which give off visible light with colors determined by the phosphor materials. This aspect is comparable to fluorescent lamps and to the neon signs that use colored phosphors.

Every pixel is made up of three separate subpixel cells, each with different colored phosphors. One subpixel has a red light phosphor, one subpixel has a green light phosphor and one subpixel has a blue light phosphor. These colors blend together to create the overall color of the pixel, the same as a triad of a shadow mask CRT or color LCD. Plasma panels use pulse-width modulation (PWM) to control brightness: by varying the pulses of current flowing through the different cells thousands of times per second, the control system can increase or decrease the intensity of each subpixel color to create billions of different combinations of red, green and blue. In this way, the control system can produce most of the visible colors. Plasma displays use the same phosphors as CRTs, which accounts for the extremely accurate color reproduction when viewing television or computer video images (which use an RGB color system designed for CRT displays).

Plasma displays are different from liquid crystal displays (LCDs), another lightweight flat-screen display using very different technology. LCDs may use one or two large fluorescent lamps as a backlight source, but the different colors are controlled by LCD units, which in effect behave as gates that allow or block light through red, green, or blue filters on the front of the LCD panel.

To produce light, the cells need to be driven at a relatively high voltage (~300 volts) and the pressure of the gases inside the cell needs to be low (~500 torr).

Contrast ratio is the difference between the brightest and darkest parts of an image, measured in discrete steps, at any given moment. Generally, the higher the contrast ratio, the more realistic the image is (though the "realism" of an image depends on many factors including color accuracy, luminance linearity, and spatial linearity). Contrast ratios for plasma displays are often advertised as high as 5,000,000:1.organic light-emitting diode. Although there are no industry-wide guidelines for reporting contrast ratio, most manufacturers follow either the ANSI standard or perform a full-on-full-off test. The ANSI standard uses a checkered test pattern whereby the darkest blacks and the lightest whites are simultaneously measured, yielding the most accurate "real-world" ratings. In contrast, a full-on-full-off test measures the ratio using a pure black screen and a pure white screen, which gives higher values but does not represent a typical viewing scenario. Some displays, using many different technologies, have some "leakage" of light, through either optical or electronic means, from lit pixels to adjacent pixels so that dark pixels that are near bright ones appear less dark than they do during a full-off display. Manufacturers can further artificially improve the reported contrast ratio by increasing the contrast and brightness settings to achieve the highest test values. However, a contrast ratio generated by this method is misleading, as content would be essentially unwatchable at such settings.

Each cell on a plasma display must be precharged before it is lit, otherwise the cell would not respond quickly enough. Precharging normally increases power consumption, so energy recovery mechanisms may be in place to avoid an increase in power consumption.LED illumination can automatically reduce the backlighting on darker scenes, though this method cannot be used in high-contrast scenes, leaving some light showing from black parts of an image with bright parts, such as (at the extreme) a solid black screen with one fine intense bright line. This is called a "halo" effect which has been minimized on newer LED-backlit LCDs with local dimming. Edgelit models cannot compete with this as the light is reflected via a light guide to distribute the light behind the panel.

Image burn-in occurs on CRTs and plasma panels when the same picture is displayed for long periods. This causes the phosphors to overheat, losing some of their luminosity and producing a "shadow" image that is visible with the power off. Burn-in is especially a problem on plasma panels because they run hotter than CRTs. Early plasma televisions were plagued by burn-in, making it impossible to use video games or anything else that displayed static images.

Plasma displays also exhibit another image retention issue which is sometimes confused with screen burn-in damage. In this mode, when a group of pixels are run at high brightness (when displaying white, for example) for an extended period, a charge build-up in the pixel structure occurs and a ghost image can be seen. However, unlike burn-in, this charge build-up is transient and self-corrects after the image condition that caused the effect has been removed and a long enough period has passed (with the display either off or on).

Plasma manufacturers have tried various ways of reducing burn-in such as using gray pillarboxes, pixel orbiters and image washing routines, but none to date have eliminated the problem and all plasma manufacturers continue to exclude burn-in from their warranties.

The first practical plasma video display was co-invented in 1964 at the University of Illinois at Urbana–Champaign by Donald Bitzer, H. Gene Slottow, and graduate student Robert Willson for the PLATO computer system.Owens-Illinois were very popular in the early 1970s because they were rugged and needed neither memory nor circuitry to refresh the images.CRT displays cheaper than the $2500 USD 512 × 512 PLATO plasma displays.

Burroughs Corporation, a maker of adding machines and computers, developed the Panaplex display in the early 1970s. The Panaplex display, generically referred to as a gas-discharge or gas-plasma display,seven-segment display for use in adding machines. They became popular for their bright orange luminous look and found nearly ubiquitous use throughout the late 1970s and into the 1990s in cash registers, calculators, pinball machines, aircraft avionics such as radios, navigational instruments, and stormscopes; test equipment such as frequency counters and multimeters; and generally anything that previously used nixie tube or numitron displays with a high digit-count. These displays were eventually replaced by LEDs because of their low current-draw and module-flexibility, but are still found in some applications where their high brightness is desired, such as pinball machines and avionics.

In 1983, IBM introduced a 19-inch (48 cm) orange-on-black monochrome display (Model 3290 Information Panel) which was able to show up to four simultaneous IBM 3270 terminal sessions. By the end of the decade, orange monochrome plasma displays were used in a number of high-end AC-powered portable computers, such as the Compaq Portable 386 (1987) and the IBM P75 (1990). Plasma displays had a better contrast ratio, viewability angle, and less motion blur than the LCDs that were available at the time, and were used until the introduction of active-matrix color LCD displays in 1992.

Due to heavy competition from monochrome LCDs used in laptops and the high costs of plasma display technology, in 1987 IBM planned to shut down its factory in Kingston, New York, the largest plasma plant in the world, in favor of manufacturing mainframe computers, which would have left development to Japanese companies.Larry F. Weber, a University of Illinois ECE PhD (in plasma display research) and staff scientist working at CERL (home of the PLATO System), co-founded Plasmaco with Stephen Globus and IBM plant manager James Kehoe, and bought the plant from IBM for US$50,000. Weber stayed in Urbana as CTO until 1990, then moved to upstate New York to work at Plasmaco.

In 1992, Fujitsu introduced the world"s first 21-inch (53 cm) full-color display. It was based on technology created at the University of Illinois at Urbana–Champaign and NHK Science & Technology Research Laboratories.

In 1994, Weber demonstrated a color plasma display at an industry convention in San Jose. Panasonic Corporation began a joint development project with Plasmaco, which led in 1996 to the purchase of Plasmaco, its color AC technology, and its American factory for US$26 million.

In 1995, Fujitsu introduced the first 42-inch (107 cm) plasma display panel;Philips introduced the first large commercially available flat-panel TV, using the Fujitsu panels. It was available at four Sears locations in the US for $14,999, including in-home installation. Pioneer also began selling plasma televisions that year, and other manufacturers followed. By the year 2000 prices had dropped to $10,000.

In the year 2000, the first 60-inch plasma display was developed by Plasmaco. Panasonic was also reported to have developed a process to make plasma displays using ordinary window glass instead of the much more expensive "high strain point" glass.

In late 2006, analysts noted that LCDs had overtaken plasmas, particularly in the 40-inch (100 cm) and above segment where plasma had previously gained market share.

Until the early 2000s, plasma displays were the most popular choice for HDTV flat panel display as they had many benefits over LCDs. Beyond plasma"s deeper blacks, increased contrast, faster response time, greater color spectrum, and wider viewing angle; they were also much bigger than LCDs, and it was believed that LCDs were suited only to smaller sized televisions. However, improvements in VLSI fabrication narrowed the technological gap. The increased size, lower weight, falling prices, and often lower electrical power consumption of LCDs made them competitive with plasma television sets.

Screen sizes have increased since the introduction of plasma displays. The largest plasma video display in the world at the 2008 Consumer Electronics Show in Las Vegas, Nevada, was a 150-inch (380 cm) unit manufactured by Matsushita Electric Industrial (Panasonic) standing 6 ft (180 cm) tall by 11 ft (330 cm) wide.

At the 2010 Consumer Electronics Show in Las Vegas, Panasonic introduced their 152" 2160p 3D plasma. In 2010, Panasonic shipped 19.1 million plasma TV panels.

Panasonic was the biggest plasma display manufacturer until 2013, when it decided to discontinue plasma production. In the following months, Samsung and LG also ceased production of plasma sets. Panasonic, Samsung and LG were the last plasma manufacturers for the U.S. retail market.

A plasma computer display is a type of flat panel display that uses tiny cells filled with electrically charged ionized gases to produce images. This display technology is used in computer monitors, televisions, and even digital billboards.The plasma computer screens are generally available in large sizes ranging from 30 inches to 50 inches, but the actual specifications depend on the brand names. This article will tell you more about plasma computer displays, while we also took time to explain other types of monitors, as well.

A plasma monitor uses gas molecules to create images. The display is composed of many cells with pixels, each one filled with plasma. Their number and size determine the resolution and the overall picture quality.

Plasma monitors bring a high level of color detail to users. These characteristics make them ideal for professional users, particularly graphic artists or studio photographers, where accurate colors are important.

Many people are afraid of plasma monitors because they sound more complex than regular monitors, but the actual technology behind them is not that hard to grasp.

A plasma display is made up of millions of cells filled with a gas, or plasma-electrically conductive gas, which contains negatively charged ions and positively charged ions.

The monitor is one of the key components of a computer system. Also known as a display, it is the part of a computer system that produces images and text that can be seen by the user.

The first plasma monitor was invented by Hiram Slottow, Robert Willson, and Donald Bitzer of the University of Illinois, Urbana-Champaign, in the 1960s, for education purposes.

Although this type of monitor was first patented in 1969 by its founders at the University of Illinois, it would take 10 years before the first commercial displays were introduced. Initially called "phosphor-based white displays,” these plasma monitors had slow refresh rates and poor-quality images.

The first commercially plasma monitors were produced in 1981 by SONY and were called the “PS-42”, with a display size of 42 inches. They began to compete commercially with CRT-based monitors and televisions.

Many electronics companies such as Samsung, Panasonic have ended the production of Plasma TVs and monitors. After the introduction of better technologies such as LCDs, LEDs, and OLEDs, plasma monitors and TVs will be a past technology.

The founders of the plasma monitor were Hiram Slottow, Robert Willson, and Donald Bitzer of the University of Illinois, Urbana-Champaign, in the 1960s.

When choosing a plasma screen as a computer monitor, you need to be aware of the different features available on the market. Here are some of the more important features that you should consider when deciding to purchase a plasma monitor.

With the arrival of better monitor technologies, plasma monitors became the least priority, and if you walk into an electronics store these days, there are very few gas plasma display monitors on display.

The reason; many people have shifted to buying LCD, LED, and other flat-panel monitors due to their superior features. The disadvantages of a plasma system monitor are:

Plasma monitor picture quality is great because it has more pixels per inch than in cathode-ray tube or CRT displays. Its higher contrast ratio also translates to great images that are crisp, sharp, and detailed. Unfortunately, Plasmas and CRTs have a common problem with backlight bleeding, simply put, a leakage of light from the edges of the screen.

This is a very common question that people ask when they want to buy a plasma monitor or when they notice their prices are higher than usual. The answer depends on several factors, such as the features they come with, brand, and size. The larger and more features it comes with, the more you should expect to pay.The average price of plasma monitors ranges from $150 to $1000, depending on the brand, size, and features.

Energy consumption of plasma monitors refers to the amount of power consumed by these devices while they are in use, either for viewing a video or presenting graphics.

These types of monitorsconsume more electricity during operation than LEDs, LCDs, according to Energy Use Calculator. Here is a table that supports this. I have included LCD displays for comparison.

Most plasma monitors have a lifespan of 100,000 hours or 11 years of use. When you take great care of them, you can count on your plasma screen to last for years before needing any repairs or replacements.

Before you run right out and buy a plasma monitor, you’ll want to make sure it has the vital capabilities you need. Having done some research online, I consider these plasma monitors to be the best since they come with the right features.

Choosing the right plasma computer monitor for your computer is no easy task. There are so many different models, sizes, brands, etc., to choose from. That"s why I"ve created this section to help you easily find the right monitor.It’s important that you are able to identify these things in order to eliminate the risk of having buyer’s remorse. The following are just a few of the features that should be considered; Screen size, screen resolution, screen aspect ratio, connectivity type, speakers, response time, color depth or picture quality, power consumption or energy efficiency.

The most important feature of a plasma pc monitor is its display resolution. Resolution is the number of pixels in a display and determines image quality.

Screen size is also an important consideration. Think about how and where you"ll be using it—if you want something portable, 15 inches is probably the max. If you plan on using it for gaming or movies, bigger is better.It is worth noting that the majority of plasma pc monitors have big screens. A larger monitor will give you more viewing area and can make editing applications easier to use. It also allows you to see more of your work at the same time, which is nice if you have more than one window open or are reading various documents and texts simultaneously.

A monitor"s refresh rate is measured in Hz, or hertz - indicates the number of times in one second that the display can completely update itself to show new data. If you are planning on purchasing a plasma gaming monitor, I would recommend that you find one with a higher refresh rate, from 75Hz and upwards.

A plasma gaming monitor with a high refresh rate will help create smoother motion on the screen. A low refresh rate will cause distracting motion blur around moving objects or distort the image when playing games.

Most plasma monitors for sale come equipped with a variety of ports and jacks for connecting computer accessories to the monitor. Make sure that the display you choose comes with the ports that you need or will require.

Installing your Dell or Hitachi plasma display monitor should not be difficult. Just gather the tools needed and follow these steps, and your new pc monitor will be up and running in no time.

Step 2: Determine the area of the wall that you want to install your plasma monitor. Make sure the area that you have chosen does not have any water pipes or electrical wires in it.

Clearing a gas plasma monitor off dust, fingerprints and other contaminations is an important maintenance routine for your computer monitor.Cleaning your monitorat least once a month will help maintain clear visibility while using your computer.

If you have a plasma monitor that is no longer in use, one solution is to turn it into a TV. It would make a good TV since many of them have large screens. To achieve this, you would need a video cable such as an HDMI or DisplayPort and a cable TV box.

DisplayPort- it looks similar to HDMI but transmits more signals, or you can achieve higher bandwidth with it. It carries both digital and analog signals, supports high resolutions, sound and video.

Do you own a plasma emission monitor? You should know about common problems you might encounter with it, including flickers or stutters, dead or stuck pixels. I will also include their solutions in this section.

Screen burn-in is a discoloration on some areas of your plasma computer monitor. It shows the remnants of images displayed for an extended period. There are many factors that can cause screen burn-in, including the use of a static image on a monitor for a long period of time.

The image is burned into the monitor, which reduces the life expectancy of the monitor. Screen burn-in can only be prevented by not leaving the display showing the same image for extended periods.

Yes, plasma monitors are suitable for gaming. They have one of the highest contrast ratios, are available with high refresh rates, have large screens and wide viewing angles too.

These great specs have gamers who want to invest in plasma monitors. They also produce better quality images which are great for entertainment like watching sports, movies, and gaming. The best plasma screens support high resolutions such as 1680 x 1050 and 1920 x 1080, which provide sharp details of things.

Businesses are becoming busier and busier, and as such, they are beginning to look for certain products to make life easier. One of the main products that businesses require is a plasma monitor for use in business meetings.

LCD (liquid crystal display) monitors use liquid crystals to produce images on the screen, while plasma monitors use gas-filled cells to produce images.

Plasma screens, on the other hand, use tiny cells with gas that gets excited when electricity is passed through them. This, in turn, produces light which lights up the color pixels.

You don’t hear much about plasma TVs these days, and for good reason: no one’s made them for several years. But for a TV technology that was once the pinnacle of picture quality, where did plasma TVs go?

But what do we recall when we talk about plasma TVs? The technology that made flat screens an everyday reality for you and I originated in a humble lab in the University of Illinois. The potential of what started as an academic experiment to create a display for educational computers became very apparent to TV manufacturers, which had been struggling to find a realistic solution to take over from cumbersome CRT (Cathode Ray Tube) TV sets.

Plasma screens feature millions of cells, filled with gas, sitting neatly between two sheets of glass. When they’re charged with electricity, the cells – or pixels – lit up to form the image. That charged-up gas is called plasma, hence the name of the screens.

CRT models, on the other hand, feature a single tube that defines the size of the screen. The move to plasma technology and its use of millions of cells made it far easier to enlarge screen sizes, while also making them thin – far more slender than normal CRT sets. In addition, the higher definition and refresh rate resulted in a much higher-quality picture.

To understand the lure of plasma and how it managed to conquer hearts and living rooms alike, you must look beyond the pretty screen and deep into the heart of the technology behind it.Next-gen TVs: the OLED, Micro LED and holographic TVs of the future

“The glass is comparable to window glass, unlike LCD. There are horizontal and vertical electrode grids and a phosphor array. The connection between the two is scanned, firing the discharge at the intersection and causing the phosphor to glow,” says analyst Paul Gray(opens in new tab), who leads TV research at Omdia, a global firm that provides analysis across the technology ecosystem. “The phosphor side is similar to CRT, while the plasma is a glow discharge like a neon lamp.”

But the genesis of the technology had nothing to do with the entertainment industry. Larry F Weber, a fellow of the Institute of Electrical and Electronics Engineers wrote the following in IEEE Transactions on Plasma Science(opens in new tab):

“As with any invention, it all started with a need. In this case, it was the need for a high-quality display for computer-based education. The University of Illinois started a project in 1960 called PLATO (Programmed Logic for Automatic Teaching Operations) to conduct research on the use of computers for education… The plasma display panel (PDP) was invented by Prof. Donald L Bitzer, Prof. H Gene Slottow, and their graduate student Robert H Wilson in 1964 to meet the need for a full graphics display for the PLATO system.”

The first manufacturer to take the dive into making plasma in serious numbers was Fujitsu, making a 42-inch screen in 1997. That screen was selling for $20,000 (around £15,000 / AU$26,000), according to San Francisco Business Times(opens in new tab).

“The starters were Fujitsu and Panasonic, but NEC, Pioneer, Samsung, LGE and Chunghwa (CPT) all made the displays,” says Gray. “Most brands had plasma in their ranges. It’s important to remember that in the early 2000s, the PDP [Plasma Display Panel] was in the lead in large-screen TVs such as 42-inch models, and there was serious concern whether 42-inch LCD was economically feasible. Sony and Sharp even worked on a hybrid technology called PALC, Plasma-addressed Liquid Crystal.”

It was the first time that a large TV was available in a form that could be mounted on a wall. This was a huge leap forward from the furniture-piece CRT TV sets that were boxy and heavy, although sturdy. Remember, also, that it was a strange world where small screens and large screens (LCD and projection respectively) were flat, but the ones in the middle (14-inch to 37-inch) were curved.

Plasma TVs had come a long way since its first iteration. It went on to dominate the consumer market for TV screens and provided one of the best viewing experiences available.

Plasma TVs had panels that lit up small cells of gases (xenon and neon) between two plates of glass, offering very bright and crisp images even on a large screen surface, according toSamsung(opens in new tab), which was one of the main manufacturers of plasma TVs. The screens contain phosphors that created the image on the screen light up themselves and don’t require backlighting.

The technology meant that large screens (typically from 42 inches to 63 inches) “offer high contrast ratios, gorgeously saturated colours, and allow for wide viewing angles – meaning every seat in the house is a great one,” according to Samsung, while it worked “well in dimly lit rooms, which is great for watching movies.” It could also “track fast-moving images without motion blur,” making plasma “ideal for watching action-packed sports or playing video games. The sharpness of visual detail is astonishing.”

However, there were some disadvantages. Plasma was more of an electricity guzzler than LCD (Panasonic had got the consumption pretty much to parity, and plasma’s power consumption depended heavily on the amount of light in the video content). It was heavier, with many more power electronics packed in each set. It wasn’t as bright, meaning that to enjoy it fully, you really needed to like your dimly lit, cinema-style watching experience – which wasn’t a disadvantage if you weren’t a fan of daytime telly. Burn-in was an issue, too, especially for avid gamers.

By 2005, six million units of plasma were being shipped globally per year, according to Omdia’s data. “The business peaked at 18.4 million in 2010,” says Gray.

But then other technologies started to catch up. LCD screens were lighter and brighter. They consumed far less energy and performed better in daylight.

“Essentially, the fundamental problem was the pace of innovation,” says Gray. “Plasma needed to counter the LCD industry, which had more players working on development. It faced either an uneconomic level of R&D or, alternatively, slowly falling behind. Samsung and LG were only in the PDP [Plasma Display Panel] market as an insurance policy, while the Japanese were unwilling to make big bets. In fairness, they acted rationally – while Korea Inc got its money back in LCD, Taiwan Inc only broke even and China Inc’s chances of ever making a positive return on its LCD investment are slim.”

The plasma honeymoon didn’t last, then, and there were some basic factors that had a severe impact on sales – including one of the criticisms commonly levelled at OLED, being low brightness.

“Plasma wasn’t as bright as LCD. Critically in US retailers, the TV area was brightly lit and PDP looked washed out,” says Gray. “Plasma – like all emissive displays – struggled with fine pixel densities. Only Panasonic managed to make a 1080p 42-inch, and even then it wasn’t a great product commercially. Manufacturing yield was reportedly poor. In the end, LCD had massive manufacturing capacity and the advantage of scale. PDP simply wasn’t unique enough.”

As manufacturers started making huge losses, they began to phase out plasma. Pioneer putting an end to the production of its much-loved Kuro screens was notable. When Panasonic announced that it would no longer make plasma screens, everybody knew that the end was near. LG and Samsung followed suit shortly after. And just like that, the light went out on plasma.What is OLED? The TV panel tech explainedToday"s best LG CX OLED deals

Vishay is a world leader in DC plasma production and custom display technology. Vishay Dale display modules allow users to personalize their products at affordable prices. A proprietary screened image display technology allows maximum freedom to design a display module that is application-specific with interface circuitry that is synergistic to the end system.

A plasma television is a type of flat panel display that employs plasma technology to achieve a high picture quality and thin form factor. Plasma TV technology was one of the major successors to CRT televisions in the late 1990s. The manufacturing of plasma displays effectively ended throughout the United States in 2014.

A plasma screen is composed of electrically charged gases held inside small light cells. The electrically charged gases are mostly made of noble gases such as neon and xenon, plus a small amount of other gases like mercury vapor. Once a voltage is applied to the gases, the light cells fire in specific patterns to create all the colors of the spectrum.

The heat of a typical plasma panel can commonly exceed 80 degrees Fahrenheit, and for a 50-inch display the power consumption is around 400 watts. Due to the hot gases and high energies involved in producing visible light on the screen, a plasma TV heats up quite high during its operations.

Yes, the TV will automatically scale the image to fit the native resolution of the display. For instance, if the native resolution is 1080p and the incoming video signal is 480p, then the TV will scale up the 480p image to fit the entire surface of the 1080p TV. The quality of the video scaling process depends on the up-scaling algorithm used by each manufacturer.

Yes, plasma screens are available in both 720p and 1080p high-definition resolutions, along with some unique resolutions in between. Plasma technology is capable of achieving higher resolutions, but few plasma TVs were produced beyond 1080p resolution.

Plasma screens can use S-video, component, composite, or HDMI, depending on the type of set. HDMI is the standard for high-definition screens, but earlier TVs may use S-video or component.

Plasma TVs contain tiny pockets of gas, and when a voltage is applied to them, they turn into a plasma state. The voltage then strikes the mercury within the plasma to emit ultraviolet (UV) rays, which pass through phosphor cells to produce an image. Each pixel in the TV contains three phosphor cells: red, green, and blue, and these three colors combine to produce a color. Essentially, plasma TVs don"t require a backlight, and each pixel is self-emissive as it produces its own light.

Unlike plasma TVs, LCD TVs use a backlight. Initially, LCD TVs used Cold-Cathode Fluorescent Lamp (CCFL) as their backlight. These are long tubes that are placed horizontally across the screen behind the LCD panel. When the light is turned on, it applies a voltage to the pixels, which makes them rotate a certain way to allow light through and produce an image. When it wants to display black, the pixels are rotated to create an opaque screen so that light doesn"t get through. This is what makes them different from plasma TVs because each pixel isn"t self-emitting.

Plasma and LED TVs each present their own advantages and disadvantages in terms of picture quality, price, build, and availability. It"s generally thought that plasma produces a better picture quality due to their superior contrast ratio, but LED TVs became more popular because of other factors, like a lower cost and greater availability.

Below you can see the differences in picture quality between two older TVs from 2013. It"s clear the plasma was better at the time, but LED TVs have also gotten better since then, so picture quality has greatly improved.

Contrast ratio was one of the main advantages and selling points of plasma TVs. Since each pixel emitted its own light, it simply turned itself off when it wanted to display a black image. This allowed the TV to display very deep blacks, but because there was always a bit of charge left in the plasma, it still wasn"t a perfect black level.

On the other hand, LED TVs can"t achieve a perfect black level because the backlight is always on. However, technology has evolved to greatly improved the contrast of LED TVs, even to the point where it"s also as good as what plasma once was. There are two main types of LCD panels in TVs: Vertical Alignment (VA) and In-Plane Switching (IPS). VA panels produce a better contrast than IPS, and high-end TVs also have local dimming features that turn off certain zones of the LED backlights. Still, you won"t get a perfect black level, but most modern LED TVs produce such deep blacks that even in a dark environment it looks like perfect black levels. For reference, plasma TVs had a max contrast of about 4,000:1, according to DisplayMate.com, but some recent LED TVs can reach a contrast of over 20,000:1 with local dimming enabled, like the Samsung QN90A QLED.

LED TVs are a clear winner here, and it"s one of the reasons why they surpassed plasmas in terms of popularity. LED TVs get significantly brighter, so they can fight glare from light sources easier. Additionally, plasma TVs had to use glass on their front panel, which caused intense glare if you had any lamps or windows around the TV. LED TVs can use a coating on their glass panel to help reflect and diffuse light, making it a better choice for well-lit rooms.

Plasmas were designed for dark-room viewing, but since most people don"t have dedicated home theater setups and often watch with a few light sources around, they weren"t that useful. As you can see below, the plasma TV had pronounced reflections, to the point where it"s even hard to see the image, and instead you"re watching yourself watch TV. Reflections are still noticeable on an LED TV, but at least you can see the image.

Pixels on plasma TVs emitted light in all directions, creating extremely wide viewing angles, much better than most LED TVs. This means that the image remained accurate when viewing from the side, which was great for watching sports or a show with a few people. Out of the two main panel types for LED TVs, IPS has wider viewing angles than VA panels, but it"s still not as good as plasma.

TV manufacturers have tried different technologies to improve viewing angles on VA panels. Samsung has an "Ultra Viewing Angle" layer, and Sony uses their "X-Wide Angle" technology to increase the viewing angles, both at the cost of a lower contrast ratio. It"s still not as good as plasma, but they"re wide enough for watching TV in a fairly large seating area.

Below you can see the differences in viewing angles between a plasma and a VA panel. These TVs were tested on different test benches, so you shouldn"t directly compare the videos, but we included them to give you an idea of how each technology affects the viewing angle.

Plasma TVs were great for motion handling, like with sports and video games due to their quick response time. Since each pixel had to retain a certain charge at any given moment, it was ready to display an image almost instantly. This meant fast-moving scenes looked crisp and smooth, with no motion blur behind them. However, for LED TVs, it can be a toss-up; some lower-end models have a slow response time that causes motion blur, while other high-end TVs have a really fast response time.

In terms of refresh rate, plasma TVs had a higher internal refresh rate, up to 600Hz, while LED TVs tend to be 60 or 120Hz. However, the refresh rate depends on the content, and since most content doesn"t go past 120 frames per second, having a higher refresh rate TV isn"t very useful.

Screen uniformity is another area where plasma TVs win. Since they didn"t have a backlight, they could evenly control each pixel. LED TVs can suffer from uniformity issues, like darker edges or Dirty Screen Effect in the center, because the backlight output may not be even across the panel. However, this is only really noticeable when watching content with large areas of uniform color, like a hockey or basketball broadcast, or if you"re going to use the TV as a PC monitor. It shouldn"t be noticeable with other types of content, and since uniformity can vary between units, you shouldn"t worry about it too much.

One of the reasons plasma TVs didn"t last too long at the top of the TV world is because of their risk of temporary image retention and permanent burn-in. Plasmas lose their brightness over the years, and in the worst case, would have permanent burn-in with certain colors staying on the screen, as you can see here. Even after watching content with static elements, like the news, for an extended period, the outline of the static elements would stay on the screen for a few minutes after changing the channel.

These problems are particularly annoying, especially if you watch a lot of TV. There was no way to help reduce this issue, and after a few years, depending on how much you used the TV, your plasma would need replacing. LEDs don"t suffer from this same permanent burn-in, so you won"t have to worry about replacing your LED TV down the line because of burn-in.

Due to their different technologies, LED and plasma TVs are built differently. Plasma TVs tended to be heavier and thicker because the panel itself was larger. Although plasmas were the first flat-screen TVs available at a consumer level at the end of the 20th century, LCD TVs quickly became even thinner, easier to package, and lighter to carry from the store to your house. These days, LED TVs are as thin as 1", like the Samsung QN85A QLED.

Plasma TVs also required a lot of power to work and tended to get very hot. With the growth of environment-friendly consumer practices, it became clear LED TVs would win out since they required a lot less electricity, and in a way were better for the environment.

Both plasma and LED TVs were made with larger sizes, but LED had a slight advantage because they were also made in displays smaller than 32 inches, like with monitors. Although small TVs are rare now, you can still find a basic 28 or 32 inch TV for a kitchen or bedroom with an LED panel. Plasma TVs weren"t made that small. LED TVs also cost less to produce and are cheaper on the market, so at the end of the day, the lower cost drove LED sales.

When 4k TVs started to become the norm over 1080p and 720p TVs in the mid-2010s, manufacturers started to produce 4k LED TVs, while plasma TVs were stuck at 1080p. This presented a major advantage for LED TVs, as a higher resolution helps create a crisper image, and this essentially was the nail in the coffin for plasma TVs. Since manufacturers were focused on making 4k LED TVs, plasma TVs became less available, and by 2014, Panasonic, LG, and Samsung all stopped their plasma production. LED TVs surpassed plasma sales in 2007, and they haven"t looked back since.

There were a few other problems that contributed to the decline of plasma TVs. First of all, plasma TVs didn"t work at high altitudes because of the change in air pressure with the gasses inside. They would create a buzzing noise, and the image wouldn"t look the same, so this could have been problematic if you lived at a high altitude. LED TVs can be used at any altitude; you shouldn"t use them in extreme cold or extreme heat, but this is standard practice for any electronic, and temperature is easier to control than your altitude. Also, plasma TVs emitted a radio frequency that could have interfered with other devices around, like if you had a radio in the same room. Each of these issues are simply inconvenient for most people.

The simple answer is yes, but it doesn"t mean you should go out tomorrow and buy a new TV just because you read this article. If you aren"t experiencing any issues with your plasma, then you probably don"t need to replace it right away. However, if you notice your plasma is starting to show some signs of permanent burn-in, it"s probably a good idea to get a new TV before the burn-in becomes worse.

There could be other advantages if you upgrade your TV, like technological advancements and a higher 4k resolution. Modern TVs come with a built-in smart system, which isn"t something that most plasmas had, and this allows you to directly stream your favorite content without the need for an external streaming device. As mentioned, LED TVs aren"t very costly, and you can easily find the best 4k TVs for under $500.

At the same time that plasma TVs met their end, OLEDs grew from the ashes of their predecessor. After LG released the first commercially available 55 inch OLED in 2012, it soon competed with LED TVs. OLED, which stands for Organic Light-Emitting Diode, is different from plasma, but shares many of the same characteristics, while also avoiding some of plasma"s downfalls.

OLEDs use self-emissive pixels, but what sets them apart is how the pixels completely shut off, creating an infinite contrast ratio and perfect black uniformity. This is an improvement from plasma because it was never able to reach those perfect blacks. OLEDs also have wide viewing angles and a near-instant response time like plasmas. Sadly, they don"t get extremely bright, but they"re still better for well-lit rooms than plasma because they get a bit brighter and have much better reflection handling. Also, OLEDs have the same burn-in risk as plasma, but this only happens with constant exposure to the same static elements, and we don"t expect it to be a problem for people who watch varied content.

Another advantage for OLED is how thin they are, especially compared to plasma, and they aren"t as heavy. For example, the LG GX OLED is a TV designed to sit flush against the wall and it"s only 0.94" thick!

Although plasma TVs once dominated the TV market for a short time at the turn of the 21st century, their disadvantages outweighed their advantages, and LED-backlit LCD TVs soon held the market share of sales. There were a few reasons for this, like burn-in issues, low peak brightness, and a thick and heavy design compared to LED TVs. Despite plasma TVs" superior overall picture quality, improved contrast, and very quick response time, it wasn"t enough to convince consumers to keep buying them once 4k LED TVs became readily available. If you still have a plasma, it"s likely you"ll need to replace it within the next few years, and you"ll probably buy a new LED TV.

Plasma TV production ended in 2015. However, they are still being used and sold in the secondary market. As a result, it"s helpful to understand how a Plasma TV works and how it compares to an LCD TV.

Within each cell, a narrow gap that contains an insulating layer, address electrode, and display electrode, separates two glass panels. In this process, neon-xenon gas is injected and sealed in plasma form during the manufacturing process.

When a Plasma TV is in use, the gas is electrically charged at specific intervals. The charged gas then strikes red, green, and blue phosphors, creating an image on the screen.

Each group of red, green, and blue phosphors is called a pixel (picture element — the individual red, green, and blue phosphors are called sub-pixels). Since Plasma TV pixels generate their light, they are referred to as "emissive" displays.

Plasma TVs can be made thin. However, even though the need for the bulky picture tube and electron beam scanning of those older CRT TVs is not required, Plasma TVs still employ burning phosphors to generate an image. As a result, Plasma TVs suffer from some of the drawbacks of CRT TVs, such as heat generation and possible screen burn-in of static images.

Unlike a Plasma TV, since there are no phosphors that light up, less power is needed for operation, and the light source in an LCD TV generates less heat than a Plasma TV. There is no radiation emitted from the screen.

Plasma TVs are more vulnerable to burn-in of static images. However, this problem diminished over the years due to "pixel orbiting" and related technologies.

Potentially shorter display lifespan. Early models had 30,000 hours or 8 hours of viewing a day for nine years, which was less than LCD. However, screen lifespan improved and 60,000-hour lifespan rating became the standard, with some sets rated as high as 100,000 hours, due to technology improvements.

Narrower effective side-to-side viewing angle than Plasma. On LCD TVs, it is common to notice color fading or color shifting as you move your viewing position further to either side of the center point.

An LCD TV was typically more expensive than an equivalent-sized (and equivalent featured) Plasma TV. However, that is no longer a factor, since companies have ceased manufacturing Plasma TVs.

Although it was possible to incorporate 4K resolution display capability into a Plasma TV, it was prohibitively expensive. When the sales of Plasma TVs started declining, TV makers decided against bringing consumer-based 4K Ultra HD Plasma TVs to market, which was another factor in their demise. The only 4K Ultra HD Plasma TVs manufactured were for commercial application use.

This mixture of gases is inert and harmless. That issue of light applied an electric current which turns it into plasma, a fluid ionized whose atoms have lost one or more of their electrons and are electrically neutral, so that the freed electrons form a cloud autour. The gas is contained in cells, corresponding to the (phosphors) sub-pixels. Each cell is addressed by an electrode line and a column electrode;

Plasma HDTVs create images using phosphors, tiny plasma containers placed between two sheets of glass. These emit ultraviolet light at colored spots of phosphor on the screen, which then glow to create the picture.

Plasma TVs tend to have deeper blacks, and stabler color over the screen"s breadth from a variety of angles, leading to smoother, more natural images than seen on LED-lit LCD screens. Plasma screens also show crisp, fast motion without blur or ghosting.

According to CNET, LED-lit LCD TVs are the brightest available. They are capable of 100 footlamberts, although this is bright enough to cause eye fatigue in a dark room. Plasmas are less bright, so they might be more difficult to see in a bright room, and will dim over time.

Plasma screens normally range from 42 inches to approximately 65 inches. Panasonic also offer some larger models, including a 152 inch TV. Plasma screens also weigh more than LED-lit LCD screens.

Plasma TVs are less energy efficient than LED-lit LCD TVs. According to Which magazine, a 42 inch screen LED-lit LCD TV will use an average of 64 watts, while an average 42 inch Plasma TV uses 195 watts.

According to PC World, users of Panasonic’s plasma TVs rate them highly reliable, with very few serious problems. In 2010, just 1 in 20 Panasonic users reported a major problem with their TVs. Older plasma TVs have a lifespan of 20,000 hours, although some newer TVs have up to 60,000 hours.

LED-lit LCD TVs are typically more expensive than Plasma TVs. For example, on Amazon.com a Panasonic LED-lit LCD 42 inch TV was listed for $900 while a Panasonic Plasma 42 inch TV costs $600.

LCD screen TVs are the most popular, followed by LED-backlit screens (which are also LCD screens, by the way). Plasma screens are less popular and more commonly available in larger sizes.1,274 LCD TVs

All major TV manufacturers sell LED-lit LCD TVs. Panasonic focuses its TV range on the Plasma TV, while other brands, such as LG and Samsung, only produce a few models, and some, such as Sony and Toshiba, no longer produce Plasma TVs at all.

With no more major manufacturers outputting plasma displays, many reports and analysts have claimed the technology is now dead. After four decades of ups and downs and innovations, it seems plasma displays are just another victim of out-with-old, in-with-the-new mindset.

Plasma displays have many advantages and are even more affordable than current LCD screens, but that still hasn"t been enough to curb public perception and boost sales. So, in memory of plasma, we"ve rounded up a brief history, complete with hallmark moments, of the technology.

A plasma display is a flat-panel display once-commonly used for televisions 30 inches in size or larger. Plasma displays are thinner than cathode ray tube displays, a technology used in the first commercially-made electronic television sets.

Plasma displays are classed plasma because each pixel in the screen is illuminated by a tiny bit of plasma. When an electrode applies an electrical current to a small cell filled with a noble gas mixture (like neon and xenon), it excites the gas, then ionizes it, and transforms it into a plasma.

The plasma then emits ultraviolet light, and once that light hits the phosphor coating lining each cell, it causes the phosphor to glow a visible light. Just think of of each individual subpixel on a plasma display as a tiny neon light or florescent tube. The technology is the same, just on a smaller scale.

Plasma displays have been known to boast better black levels than many LCD screens, although LCD technology has greatly improved in recent years. Pricier LED-backlit LCD screens with local dimming, for instance, have black levels comparable to those of plasma displays.

Due to how plasma displays work, they can provide precise control of the relative level of brightness and intensity for red, blue, and green subpixels. The displays therefore have deep contrast, textured images, and rich colours. Due to the lack of polarising filters, they have good viewing angles too.

Another advantage is that the florescent phosphor coating lining each subpixel can stop glowing within nanoseconds, eliminating a problem known as motion blur. Pixels in lower-end LCD screens cannot shutter or close as fast, meaning they have poor refresh rates, which results in motion blur.

Burn-in was a problem often associated with early plasma displays, but it can still occur today. It happens when the same picture is displayed for long periods. If something bright is shown on a plasma display for too long (such as a network logo), it could leave a visible-yet-faint image behind.

Plasma displays are also known for their large energy consumption, especially compared to, for instance, an LED-backlit LCD screen. And despite all that energy waste, plasma displays, which are highly glossy and reflective, sometimes don"t shine as bright as new LED or CCFL-backlit LCD screens.

Kalman Tihanyi, a Hungarian engineer, developed the first flat-panel display system in 1963, and about one year later, a monochrome plasma display was invented and presented at the University of Illinois at Urbana-Champaign for the PLATO Computer System.

Manufacturers like Ownes-Illinois and Burroughs Corporation made plasma displays, which were known for their neon orange and monochrome look, throughout the 1970s. IBM then popped into the plasma scene in 1983, when it introduced a 19-inch orange-on-black monochrome display.

The 1990s saw the emergence of full-colour plasma displays. Fujitsu demonstrated a 21-inch hybrid display in 1992 at the University of Illinois at Urbana-Champaign, and then three years later, it introduced the first 42-inch plasma display with a 852x480 resolution.

Philips followed Fujitsu’s footprint and came out with a plasma display of the same resolution in 1997. It was marketed with a steep price tag of $14,999. That same year, Pioneer entered the market of making and selling plasma displays. And the rest is history.

Panasonic showed off a 103-inch plasma display panel at CES 2006. The display had 1080p HDTV resolution and was the world’s largest plasma display at that time, edging narrowly ahead of the 102-inch Samsung plasma display shown off the previous year.

Panasonic (then called Matsushita Electric Industrial) made jaws drop again in 2008, when it showed off a 150-inch set at CES 2008. The display stood 6-ft tall by 11-ft wide. By this time however, plasma displays had peaked in popularity and were steadily losing ground to LCD screens.

Nonetheless, Panasonic once again stole the show floor at CES when it debuted a 152-inch plasma television that had 4K resolution and 3D technology. The television set cost well-over $500,000 when it launched.

There have been many plasma display manufacturers over the last few decades, but the following were known for their world-class displays: Panasonic, Pioneer, Samsung, LG, Toshiba, Sanyo, Magnavox, Sony, Vizio, LG, and Hitachi.

The company sold many of its Kuro-branded plasma technology patents to Panasonic, one of the last remaining manufacturers concentrating on plasma displays. That said, Panasonic eventually ended sales of plasma displays in March 2014.

The Consumer Electronics Association revealed in 2013 that Americans spent $2.15 billion on 2.98 million plasma displays in 2012. In comparison, during that same year, Americans spent about $16.8 billion on about 36.2 million LCD screens.

It’s not clear why Americans (and the rest of the world, for that matter) drifted away from plasma displays. The technology, which was once expensive, was more affordable than many LCD screens on the market.

Some reports have claimed that LCD is widely perceived by consumers as being both better and newer than plasma. Perhaps it"s because LCD screens tend to appear brighter and don’t have burn-in issues. They also use less electricity, a growing concern for budget-conscious and green shoppers.

Although the 2013 report from the Consumer Electronics Association forecasted that Americans would buy 1.33 million plasm