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104-681: The Apple Monitor II is a CRT -based green monochrome 12-inch monitor manufactured by Sanyo for Apple Computer ; for the Apple II . Apple introduced the monitor halfway through the lifespan of the II series. The business-oriented Apple III has the Apple Monitor III , released long before. Many home users of Apple II computers used televisions as computer monitors before the Monitor II. It has an inner vertical -swiveling frame. This allows users to adjust

208-542: 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

312-424: A frame of video on an analog television set (TV), digital raster graphics on a computer monitor , or other phenomena like radar targets. A CRT in a TV is commonly called a picture tube . CRTs have also been used as memory devices , in which case the screen is not intended to be visible to an observer. The term cathode ray was used to describe electron beams when they were first discovered, before it

416-479: A 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

520-405: 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

624-419: A voltage multiplier for the current delivered by the flyback. For the inner funnel coating, monochrome CRTs use aluminum while color CRTs use aquadag ; Some CRTs may use iron oxide on the inside. On the outside, most CRTs (but not all) use aquadag. Aquadag is an electrically conductive graphite-based paint. In color CRTs, the aquadag is sprayed onto the interior of the funnel whereas historically aquadag

728-455: A CRT and limits its practical size (see § Size ). The funnel and neck glass comprise the remaining 30% and 5% respectively. The glass in the funnel can vary in thickness, to join the thin neck with the thick screen. Chemically or thermally tempered glass may be used to reduce the weight of the CRT glass. The outer conductive coating is connected to ground while the inner conductive coating

832-472: A CRT as a display device. The Braun tube became the foundation of 20th century TV. In 1908, Alan Archibald Campbell-Swinton , fellow of the Royal Society (UK), published a letter in the scientific journal Nature , in which he described how "distant electric vision" could be achieved by using a cathode-ray tube (or "Braun" tube) as both a transmitting and receiving device. He expanded on his vision in

936-406: A CRT can be measured by the screen's entire area (or face diagonal ) or alternatively by only its viewable area (or diagonal) that is coated by phosphor and surrounded by black edges. While the viewable area may be rectangular, the edges of the CRT may have a curvature (e.g. black stripe CRTs, first made by Toshiba in 1972) or the edges may be black and truly flat (e.g. Flatron CRTs), or

1040-515: A CRT is related to its screen size. Usual deflection angles were 90° for computer monitor CRTs and small CRTs and 110° which was the standard in larger TV CRTs, with 120 or 125° being used in slim CRTs made since 2001–2005 in an attempt to compete with LCD TVs. Over time, deflection angles increased as they became practical, from 50° in 1938 to 110° in 1959, and 125° in the 2000s. 140° deflection CRTs were researched but never commercialized, as convergence problems were never resolved. The size of

1144-440: A CRT is usually made up of three parts: A screen/faceplate/panel, a cone/funnel, and a neck. The joined screen, funnel and neck are known as the bulb or envelope. The neck is made from a glass tube while the funnel and screen are made by pouring and then pressing glass into a mold. The glass, known as CRT glass or TV glass, needs special properties to shield against x-rays while providing adequate light transmission in

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1248-501: A Hungarian engineer, described a proposed flat-panel plasma display system in a 1936 paper. 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 . The goal was to create a display that had inherent memory to reduce the cost of

1352-416: 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. Plasma displays do not work as well at high altitudes above 6,500 feet (2,000 meters) due to pressure differential between the gases inside the screen and the air pressure at altitude. It may cause a buzzing noise. Manufacturers rate their screens to indicate

1456-426: A cathode in the rear of the CRT, causing it to emit electrons which are modulated and focused by electrodes. The electrons are steered by deflection coils or plates, and an anode accelerates them towards the phosphor -coated screen, which generates light when hit by the electrons. Cathode rays were discovered by Julius Plücker and Johann Wilhelm Hittorf . Hittorf observed that some unknown rays were emitted from

1560-402: 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 . In

1664-526: A cross hatch pattern. CRT glass used to be made by dedicated companies such as AGC Inc. , O-I Glass , Samsung Corning Precision Materials, Corning Inc. , and Nippon Electric Glass ; others such as Videocon, Sony for the US market and Thomson made their own glass. The funnel and the neck are made of leaded potash-soda glass or lead silicate glass formulation to shield against x-rays generated by high voltage electrons as they decelerate after striking

1768-599: 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. This precharging means

1872-443: 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

1976-410: 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. 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. None to date have eliminated

2080-600: A mainstay of display technology for decades, CRT-based computer monitors and TVs are now obsolete . Demand for CRT screens dropped in the late 2000s. Despite efforts from Samsung and LG to make CRTs competitive with their LCD and plasma counterparts, offering slimmer and cheaper models to compete with similarly sized and more expensive LCDs, CRTs eventually became obsolete and were relegated to developing markets and vintage enthusiasts once LCDs fell in price, with their lower bulk, weight and ability to be wall mounted coming as pluses. Some industries still use CRTs because it

2184-426: A metal funnel insulated with polyethylene instead of glass with conductive material. Others had ceramic or blown Pyrex instead of pressed glass funnels. Early CRTs did not have a dedicated anode cap connection; the funnel was the anode connection, so it was live during operation. The funnel is coated on the inside and outside with a conductive coating, making the funnel a capacitor, helping stabilize and filter

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2288-463: 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

2392-547: 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

2496-419: A reference. In modern CRT monitors and TVs the beams are bent by magnetic deflection , using a deflection yoke . Electrostatic deflection is commonly used in oscilloscopes. The tube is a glass envelope which is heavy, fragile, and long from front screen face to rear end. Its interior must be close to a vacuum to prevent the emitted electrons from colliding with air molecules and scattering before they hit

2600-464: A sheet of glass and the electrons were accelerated to a nearby sheet of glass with phosphors using an anode voltage. The electrons were not focused, making each subpixel essentially a flood beam CRT. They were never put into mass production as LCD technology was significantly cheaper, eliminating the market for such displays. The last large-scale manufacturer of (in this case, recycled) CRTs, Videocon , ceased in 2015. CRT TVs stopped being made around

2704-457: A slight edge in picture quality and a price advantage for sets at the critical 42" size and larger. By late 2006, several vendors were offering 42" LCDs, albeit at a premium price, encroaching upon plasma's only stronghold. More decisively, LCDs offered higher resolutions and true 1080p support, while plasmas were stuck at 720p , which made up for the price difference. In late 2006, analysts noted that LCDs had overtaken plasmas, particularly in

2808-666: A speech given in London in 1911 and reported in The Times and the Journal of the Röntgen Society . The first cathode-ray tube to use a hot cathode was developed by John Bertrand Johnson (who gave his name to the term Johnson noise ) and Harry Weiner Weinhart of Western Electric , and became a commercial product in 1922. The introduction of hot cathodes allowed for lower acceleration anode voltages and higher electron beam currents, since

2912-444: A target, such as the phosphor screen or shadow mask of a color CRT. The velocity of the electrons depends on the anode voltage of the CRT; the higher the voltage, the higher the speed. The amount of x-rays emitted by a CRT can also lowered by reducing the brightness of the image. Leaded glass is used because it is inexpensive, while also shielding heavily against x-rays, although some funnels may also contain barium. The screen

3016-530: A tradeoff between the two. It consists of a metal clip that expands on the inside of an anode button that is embedded on the funnel glass of the CRT. The connection is insulated by a silicone suction cup, possibly also using silicone grease to prevent corona discharge . Plasma display Until about 2007, plasma displays were commonly used in large televisions. By 2013, they had lost nearly all market share due to competition from low-cost liquid crystal displays ( LCD )s. Manufacturing of plasma displays for

3120-426: Is a stub . You can help Misplaced Pages by expanding it . This article about Apple Inc. is a stub . You can help Misplaced Pages by expanding it . Cathode-ray tube A cathode-ray tube ( CRT ) is a vacuum tube containing one or more electron guns , which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms on an oscilloscope ,

3224-413: 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

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3328-422: Is added to the neon to increase hysteresis . Plasma panels may be built without nitrogen gas, using xenon, neon, argon, and helium instead with mercury being used in some early displays. In color panels, the back of each cell is coated with a 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

3432-406: 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

3536-440: Is connected using the anode button/cap through a series of capacitors and diodes (a Cockcroft–Walton generator ) to the high voltage flyback transformer ; the inner coating is the anode of the CRT, which, together with an electrode in the electron gun, is also known as the final anode. The inner coating is connected to the electrode using springs. The electrode forms part of a bipotential lens. The capacitors and diodes serve as

3640-677: Is either too much effort, downtime, and/or cost to replace them, or there is no substitute available; a notable example is the airline industry. Planes such as the Boeing 747-400 and the Airbus A320 used CRT instruments in their glass cockpits instead of mechanical instruments. Airlines such as Lufthansa still use CRT technology, which also uses floppy disks for navigation updates. They are also used in some military equipment for similar reasons. As of 2022 , at least one company manufactures new CRTs for these markets. A popular consumer usage of CRTs

3744-399: Is for retrogaming . Some games are impossible to play without CRT display hardware. Light guns only work on CRTs because they depend on the progressive timing properties of CRTs. Another reason people use CRTs due to the natural blending of these displays. Some games designed for CRT displays exploit this, which allows them to look more aesthetically pleasing on these displays. The body of

3848-506: Is gradually reduced. This means that flat-screen CRTs may not be completely flat on the inside. The glass used in CRTs arrives from the glass factory to the CRT factory as either separate screens and funnels with fused necks, for Color CRTs, or as bulbs made up of a fused screen, funnel and neck. There were several glass formulations for different types of CRTs, that were classified using codes specific to each glass manufacturer. The compositions of

3952-526: Is normally necessary because plasma displays have to be baked during manufacture to dry the rare-earth phosphors after they are applied to the display. However, high strain point glass may be less scratch resistant. 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

4056-548: Is not always noticeable. High-end computer monitors have technologies to try to compensate for the uniformity problem. 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. On

4160-404: 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

4264-419: Is usually instead made out of a special lead-free silicate glass formulation with barium and strontium to shield against x-rays, as it doesn't brown unlike glass containing lead. Another glass formulation uses 2–3% of lead on the screen. Alternatively zirconium can also be used on the screen in combination with barium, instead of lead. Monochrome CRTs may have a tinted barium-lead glass formulation in both

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4368-471: The Aiken tube was invented. It was a CRT in a flat-panel display format with a single electron gun. Deflection was electrostatic and magnetic, but due to patent problems, it was never put into production. It was also envisioned as a head-up display in aircraft. By the time patent issues were solved, RCA had already invested heavily in conventional CRTs. 1968 marked the release of Sony Trinitron brand with

4472-486: The cathode (negative electrode) which could cast shadows on the glowing wall of the tube, indicating the rays were travelling in straight lines. In 1890, Arthur Schuster demonstrated cathode rays could be deflected by electric fields , and William Crookes showed they could be deflected by magnetic fields. In 1897, J. J. Thomson succeeded in measuring the mass-to-charge ratio of cathode rays, showing that they consisted of negatively charged particles smaller than atoms,

4576-500: 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

4680-436: The 40-inch (100 cm) and above segment where plasma had previously gained market share. Another industry trend was the consolidation of plasma display manufacturers, with around 50 brands available but only five manufacturers. In the first quarter of 2008, a comparison of worldwide TV sales broke down to 22.1 million for direct-view CRT, 21.1 million for LCD, 2.8 million for plasma, and 0.1 million for rear projection. When

4784-421: The CRT cathode wears out due to cathode poisoning before browning becomes apparent. The glass formulation determines the highest possible anode voltage and hence the maximum possible CRT screen size. For color, maximum voltages are often 24–32 kV, while for monochrome it is usually 21 or 24.5 kV, limiting the size of monochrome CRTs to 21 inches, or ~1 kV per inch. The voltage needed depends on

4888-461: The CRT. In 1954, RCA produced some of the first color CRTs, the 15GP22 CRTs used in the CT-100 , the first color TV set to be mass produced . The first rectangular color CRTs were also made in 1954. However, the first rectangular color CRTs to be offered to the public were made in 1963. One of the challenges that had to be solved to produce the rectangular color CRT was convergence at the corners of

4992-459: The CRT. In 1965, brighter rare earth phosphors began replacing dimmer and cadmium-containing red and green phosphors. Eventually blue phosphors were replaced as well. The size of CRTs increased over time, from 20 inches in 1938, to 21 inches in 1955, 25 inches by 1974, 30 inches by 1980, 35 inches by 1985, and 43 inches by 1989. However, experimental 31 inch CRTs were made as far back as 1938. In 1960,

5096-587: The United States retail market ended in 2014, and manufacturing for the Chinese market ended in 2016. Plasma displays are obsolete, having been superseded in most if not all aspects by OLED displays. Competing display technologies include cathode-ray tube (CRT), organic light-emitting diode (OLED), CRT projectors , AMLCD , Digital Light Processing DLP, SED-tv , LED display , field emission display (FED), and quantum dot display (QLED). Kálmán Tihanyi ,

5200-551: The altitude parameters. For those who wish to listen to AM radio , or are amateur radio operators (hams) or shortwave listeners (SWL), the radio frequency interference (RFI) from these devices can be irritating or disabling. In their heyday, they were less expensive for the buyer per square inch than LCD, particularly when considering equivalent performance. Plasma displays have 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

5304-408: The anode now only accelerated the electrons emitted by the hot cathode, and no longer had to have a very high voltage to induce electron emission from the cold cathode. In 1926, Kenjiro Takayanagi demonstrated a CRT TV receiver with a mechanical video camera that received images with a 40-line resolution. By 1927, he improved the resolution to 100 lines, which was unrivaled until 1931. By 1928, he

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5408-441: The anode voltage of the CRT, and significantly reducing the amount of time needed to turn on a CRT. The stability provided by the coating solved problems inherent to early power supply designs, as they used vacuum tubes. Because the funnel is used as a capacitor, the glass used in the funnel must be an excellent electrical insulator ( dielectric ). The inner coating has a positive voltage (the anode voltage that can be several kV) while

5512-541: The cells cannot achieve a true black, whereas an LED backlit LCD panel can actually turn off parts of the backlight, in "spots" or "patches" (this technique, however, does not prevent the large accumulated passive light of adjacent lamps, and the reflection media, from returning values from within the panel). Some manufacturers have reduced the precharge and the associated background glow, to the point where black levels on modern plasmas are starting to become close to some high-end CRTs Sony and Mitsubishi produced ten years before

5616-423: 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. A magnesium oxide layer may be present to protect the dielectric layer and to emit secondary electrons. Control circuitry charges the electrodes that cross paths at

5720-408: The center of the screen with a 546 nm wavelength light, and a 10.16mm thick screen. Transmittance goes down with increasing thickness. Standard transmittances for Color CRT screens are 86%, 73%, 57%, 46%, 42% and 30%. Lower transmittances are used to improve image contrast but they put more stress on the electron gun, requiring more power on the electron gun for a higher electron beam power to light

5824-426: The comparable plasma displays. With an LCD, black pixels are generated by a light polarization method; many panels are unable to completely block the underlying backlight. More recent LCD panels using 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

5928-485: 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 LCDs.) LED-backlit LCD televisions have been developed to reduce this distinction. The display panel itself

6032-429: The early 2010s, CRTs have been superseded by flat-panel display technologies such as LCD , plasma display , and OLED displays which are cheaper to manufacture and run, as well as significantly lighter and thinner. Flat-panel displays can also be made in very large sizes whereas 40–45 inches (100–110 cm) was about the largest size of a CRT. A CRT works by electrically heating a tungsten coil which in turn heats

6136-630: The end of the decade, orange monochrome plasma displays were used in a number of high-end AC -powered portable computers , such as the Ericsson Portable PC (the first use of such a display in 1985), 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

6240-727: 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. Plasma displays are capable of producing deeper blacks than LCD allowing for a superior contrast ratio. 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 . Image burn-in occurs on CRTs and plasma panels when

6344-499: The first " subatomic particles ", which had already been named electrons by Irish physicist George Johnstone Stoney in 1891. The earliest version of the CRT was known as the "Braun tube", invented by the German physicist Ferdinand Braun in 1897. It was a cold-cathode diode , a modification of the Crookes tube with a phosphor -coated screen. Braun was the first to conceive the use of

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6448-655: The first 42-inch (107 cm) plasma display panel; it had 852×480 resolution and was progressively scanned. Two years later, Philips introduced at CES and CeBIT the first large commercially available flat-panel TV, using the Fujitsu panels. Philips had plans to sell it for 70,000 french francs. It was released as the Philips 42PW9962. It was available at four Sears locations in the US for $ 14,999, including in-home installation. Pioneer and Fujitsu also began selling plasma televisions that year, and other manufacturers followed. By

6552-651: The first CRT with HD resolution, the Sony KW-3600HD, was released to the market. It is considered to be "historical material" by Japan's national museum. The Sony KWP-5500HD, an HD CRT projection TV, was released in 1992. In the mid-1990s, some 160 million CRTs were made per year. In the mid-2000s, Canon and Sony presented the surface-conduction electron-emitter display and field-emission displays , respectively. They both were flat-panel displays that had one (SED) or several (FED) electron emitters per subpixel in place of electron guns. The electron emitters were placed on

6656-467: The first CRTs to last 1,000  hours of use, which was one of the factors that led to the widespread adoption of TV. The first commercially made electronic TV sets with cathode-ray tubes were manufactured by Telefunken in Germany in 1934. In 1947, the cathode-ray tube amusement device , the earliest known interactive electronic game as well as the first to incorporate a cathode-ray tube screen,

6760-463: The first manufacturers to stop CRT production was Hitachi in 2001, followed by Sony in Japan in 2004, Flat-panel displays dropped in price and started significantly displacing cathode-ray tubes in the 2000s. LCD monitor sales began exceeding those of CRTs in 2003–2004 and LCD TV sales started exceeding those of CRTs in some markets in 2005. Samsung SDI stopped CRT production in 2012. Despite being

6864-401: The furnace, to allow production of CRTs of several sizes. Only the glass used on the screen needs to have precise optical properties. The optical properties of the glass used on the screen affect color reproduction and purity in color CRTs. Transmittance, or how transparent the glass is, may be adjusted to be more transparent to certain colors (wavelengths) of light. Transmittance is measured at

6968-457: 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

7072-462: 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. Dr. Larry F. Weber ,

7176-523: 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

7280-489: The melts were also specific to each manufacturer. Those optimized for high color purity and contrast were doped with Neodymium, while those for monochrome CRTs were tinted to differing levels, depending on the formulation used and had transmittances of 42% or 30%. Purity is ensuring that the correct colors are activated (for example, ensuring that red is displayed uniformly across the screen) while convergence ensures that images are not distorted. Convergence may be modified using

7384-589: The model KV-1310, which was based on Aperture Grille technology. It was acclaimed to have improved the output brightness. The Trinitron screen was identical with its upright cylindrical shape due to its unique triple cathode single gun construction. In 1987, flat-screen CRTs were developed by Zenith for computer monitors, reducing reflections and helping increase image contrast and brightness. Such CRTs were expensive, which limited their use to computer monitors. Attempts were made to produce flat-screen CRTs using inexpensive and widely available float glass . In 1990,

7488-530: The outer coating is connected to ground. CRTs powered by more modern power supplies do not need to be connected to ground , due to the more robust design of modern power supplies. The value of the capacitor formed by the funnel is 5–10  nF , although at the voltage the anode is normally supplied with. The capacitor formed by the funnel can also suffer from dielectric absorption , similarly to other types of capacitors. Because of this CRTs have to be discharged before handling to prevent injury. The depth of

7592-970: 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 . These were interlaced displays, with non-square pixels. 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

7696-443: The phosphors more brightly to compensate for the reduced transmittance. The transmittance must be uniform across the screen to ensure color purity. The radius (curvature) of screens has increased (grown less curved) over time, from 30 to 68 inches, ultimately evolving into completely flat screens, reducing reflections. The thickness of both curved and flat screens gradually increases from the center outwards, and with it, transmittance

7800-445: 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

7904-488: The plasma displays' relatively large screen size and 1 inch thickness made them suitable for high-profile placement in lobbies and stock exchanges. 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, uses the same technology as later plasma video displays, but began life as

8008-409: The power (around 500–700 watts) of a "home" setting of less extreme brightness. The lifetime of the latest generation of plasma displays is estimated at 100,000 hours (11 years) of actual display time, or 27 years at 10 hours per day. This is the estimated time over which maximum picture brightness degrades to half the original value. Plasma screens are made out of glass, which may result in glare on

8112-415: The problem and all plasma manufacturers continue to exclude burn-in from their warranties. 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

8216-412: The sales figures for the 2007 Christmas season were finally tallied, analysts were surprised to find that not only had LCD outsold plasma, but CRTs as well, during the same period. This development drove competing large-screen systems from the market almost overnight. The February 2009 announcement that Pioneer Electronics was ending production of plasma screens was widely considered the tipping point in

8320-473: 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

8424-674: The same time. In 2012, Samsung SDI and several other major companies were fined by the European Commission for price fixing of TV cathode-ray tubes. The same occurred in 2015 in the US and in Canada in 2018. Worldwide sales of CRT computer monitors peaked in 2000, at 90 million units, while those of CRT TVs peaked in 2005 at 130 million units. Beginning in the late 1990s to the early 2000s, CRTs began to be replaced with LCDs, starting first with computer monitors smaller than 15 inches in size, largely because of their lower bulk. Among

8528-406: The screen and funnel, with a potash-soda lead glass in the neck; the potash-soda and barium-lead formulations have different thermal expansion coefficients. The glass used in the neck must be an excellent electrical insulator to contain the voltages used in the electron optics of the electron gun, such as focusing lenses. The lead in the glass causes it to brown (darken) with use due to x-rays, usually

8632-409: The screen can reach a temperature of at least 1,200 °C (2,190 °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

8736-851: The screen from nearby light sources. Plasma display panels cannot be economically manufactured in screen sizes smaller than 82 centimetres (32 in). Although a few companies have been able to make plasma 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 was rapidly disappearing by mid-2009. 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. Plasma displays are generally heavier than LCD and may require more careful handling, such as being kept upright. Plasma displays use more electrical power, on average, than an LCD TV using

8840-427: The screen may contain 12% of barium oxide , and 12% of strontium oxide . A typical CRT contains several kilograms of lead as lead oxide in the glass depending on its size; 12 inch CRTs contain 0.5 kg of lead in total while 32 inch CRTs contain up to 3 kg. Strontium oxide began being used in CRTs, its major application, in the 1970s. Before this, CRTs used lead on the faceplate. Some early CRTs used

8944-449: The screen or being very electrically insulating in the funnel and neck. The formulation that gives the glass its properties is also known as the melt. The glass is of very high quality, being almost contaminant and defect free. Most of the costs associated with glass production come from the energy used to melt the raw materials into glass. Glass furnaces for CRT glass production have several taps to allow molds to be replaced without stopping

9048-486: The shipments of plasma TVs reached 18.2 million units globally. Since that time, shipments of plasma TVs have declined substantially. This decline has been attributed to the competition from liquid crystal (LCD) televisions, whose prices have fallen more rapidly than those of the plasma TVs. In late 2013, Panasonic announced that they would stop producing plasma TVs from March 2014 onwards. In 2014, LG and Samsung discontinued plasma TV production as well, effectively killing

9152-444: The size and type of CRT. Since the formulations are different, they must be compatible with one another, having similar thermal expansion coefficients. The screen may also have an anti-glare or anti-reflective coating, or be ground to prevent reflections. CRTs may also have an anti-static coating. The leaded glass in the funnels of CRTs may contain 21–25% of lead oxide (PbO), The neck may contain 30–40% of lead oxide, and

9256-448: The surface, this is a significant advantage of plasma over most other current display technologies, a notable exception being 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

9360-662: The technology's history as well. 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 (340 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. In 2010,

9464-402: The technology, probably because of lowering demand. 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,

9568-425: The terminals. The original neon orange monochrome Digivue display panels built by glass producer Owens-Illinois were very popular in the early 1970s because they were rugged and needed neither memory nor circuitry to refresh the images. A long period of sales decline occurred in the late 1970s because semiconductor memory made CRT displays cheaper than the $ 2500 USD 512 × 512 PLATO plasma displays. Nevertheless,

9672-436: The tube's face. Thus, the interior is evacuated to less than a millionth of atmospheric pressure . As such, handling a CRT carries the risk of violent implosion that can hurl glass at great velocity. The face is typically made of thick lead glass or special barium - strontium glass to be shatter-resistant and to block most X-ray emissions. This tube makes up most of the weight of CRT TVs and computer monitors. Since

9776-457: The viewable area may follow the curvature of the edges of the CRT (with or without black edges or curved edges). Small CRTs below 3 inches were made for handheld TVs such as the MTV-1 and viewfinders in camcorders. In these, there may be no black edges, that are however truly flat. Most of the weight of a CRT comes from the thick glass screen, which comprises 65% of the total weight of

9880-597: The viewing angle up or down without the addition of a tilt-and-swivel device. The Monitor II was widely adjustable for the time, including adjustments for the size and location of the image on the screen. These adjustments have a very small influence on the picture. The Monitor II was designed for the Apple II+ , but was used widely throughout the Apple II product line, most commonly on the Apple IIe . This computer hardware article

9984-463: 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). 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). Plasma displays are bright (1,000  lux or higher for

10088-635: 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. Plasma displays have 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. Plasma displays have superior uniformity to LCD panel backlights, which nearly always produce uneven brightness levels, although this

10192-455: 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. High strain point glass is made similarly to conventional float glass, but it is more heat resistant, deforming at higher temperatures. High strain point glass

10296-503: 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

10400-516: Was believed that LCDs were suited only to smaller sized televisions. Plasma had overtaken rear-projection systems in 2005. However, improvements in LCD 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. In 2006, LCD prices started to fall rapidly and their screen sizes increased, although plasma televisions maintained

10504-421: Was created. From 1949 to the early 1960s, there was a shift from circular CRTs to rectangular CRTs, although the first rectangular CRTs were made in 1938 by Telefunken. While circular CRTs were the norm, European TV sets often blocked portions of the screen to make it appear somewhat rectangular while American sets often left the entire front of the CRT exposed or only blocked the upper and lower portions of

10608-428: Was painted into the interior of monochrome CRTs. The anode is used to accelerate the electrons towards the screen and also collects the secondary electrons that are emitted by the phosphor particles in the vacuum of the CRT. The anode cap connection in modern CRTs must be able to handle up to 55–60kV depending on the size and brightness of the CRT. Higher voltages allow for larger CRTs, higher image brightness, or

10712-425: Was the first to transmit human faces in half-tones on a CRT display. In 1927, Philo Farnsworth created a TV prototype. The CRT was named in 1929 by inventor Vladimir K. Zworykin . He was subsequently hired by RCA , which was granted a trademark for the term "Kinescope", RCA's term for a CRT, in 1932; it voluntarily released the term to the public domain in 1950. In the 1930s, Allen B. DuMont made

10816-416: Was understood that what was emitted from the cathode was a beam of electrons. In CRT TVs and computer monitors, the entire front area of the tube is scanned repeatedly and systematically in a fixed pattern called a raster . In color devices, an image is produced by controlling the intensity of each of three electron beams , one for each additive primary color (red, green, and blue) with a video signal as

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