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18 novembre 2011 5 18 /11 /novembre /2011 02:43

 

History and science

Neon is a chemical element and an inert gas that is a minor component of the Earth's atmosphere. It was discovered in 1898 byWilliam Ramsey and Morris W. Travers.Sony VAIO VGN-CR71B/W Battery

When Ramsey and Travers had succeeded in obtaining some pure neon from the atmosphere, they explored its properties using an "electrical gas-discharge" tube that was similar to the tubes used today for neon signs. Travers later wrote, "the blaze of crimson light from the tube told its own story and was a sight to dwell upon and never forget."Sony VAIO VGN-CR72B/W Battery

The procedure of examining the colors of the light emitted from gas-discharge (or "Geissler" tubes) was well-known at the time, since the colors of light (the "spectral lines") emitted by a gas discharge tube are, essentially, fingerprints that identify the gases inside.Sony VAIO VGN-CR90HS Battery

Immediately following neon's discovery, neon tubes were used as scientific instruments and novelties. However, the scarcity of purified neon gas precluded its prompt application for electrical gas-discharge lighting along the lines of Moore tubes,Sony VAIO VGN-CR90NS Battery

which used more common nitrogen or carbon dioxide as the working gas, and enjoyed some commercial success in the US in the early 1900s. After 1902, Georges Claude's company in France, Air Liquide, began producing industrial quantities of neon essentially as a byproduct of the air liquefaction business. From December 3–18, 1910, Claude demonstrated two large (12 metres (39 ft) long), bright red neon tubes at the Paris Motor Show.Sony VAIO VGN-CR90S Battery

These neon tubes were essentially in their contemporary form. The range of outer diameters for the glass tubing used in neon lighting is 9 to 25 mm; with standard electrical equipment, the tubes can be as long as 30 metres (98 ft).Sony VAIO VGN-CR92HS Battery

The pressure of the gas inside is in the range 3-20 Torr (0.4-3 kPa), which corresponds to a partial vacuum in the tubing. Claude had also solved two technical problems that substantially shortened the working life of neon and some other gas discharge tubes, and effectively gave birth to a neon lighting industry. Sony VAIO VGN-CR92NS Battery

In 1915 a US patent was issued to Claude covering the design of the electrodes for gas-discharge lighting; this patent became the basis for the monopoly held in the US by his company, Claude Neon Lights, for neon signs through the early 1930s.

Claude's patents envisioned the use of gases such as argon and mercury vapor to create different colors beyond those produced by neon. Sony VAIO VGN-CR92S Battery

In the 1920s, fluorescent glasses and coatings were developed to further expand the range of colors and effects for tubes with argon gas or argon-neon mixtures; generally, the fluorescent coatings are used with an argon/mercury-vapor mixture, which emits ultraviolet light that activates the fluorescent coatings.Sony VAIO VGN-CS118E/Q Battery

By the 1930s, the colors from combinations of neon tube lights had become satisfactory for some general interior lighting applications, and achieved some success in Europe, but not in the US. Since the 1950s, the development of phosphors for color televisions has created nearly 100 new colors for neon tube lighting.Sony VAIO VGN-CS118E/R Battery

Around 1917, Daniel McFarlan Moore, then working at the General Electric Company, developed the miniature neon lamp. The glow lamp has a very different design than the much larger neon tubes used for signage; the difference was sufficient that a separate US patent was issued for the lamp in 1919.Sony VAIO VGN-CS118E/W Battery

A Smithsonian Institution website notes, "These small, low power devices use a physical principle called "coronal discharge." Moore mounted two electrodes close together in a bulb and added neon or argon gas. The electrodes would glow brightly in red or blue, depending on the gas, and the lamps lasted for years. Sony VAIO VGN-CS11S/P Battery

Since the electrodes could take almost any shape imaginable, a popular application has been fanciful decorative lamps. Glow lamps found practical use as electronic components, and as indicators in instrument panels and in many home appliances until the acceptance of Light-Emitting Diodes (LEDs) starting in the 1970s."Sony VAIO VGN-CS11S/Q Battery

Although some neon lamps themselves are now antiques, and their use in electronics has declined markedly, the technology has continued to develop in artistic and entertainment contexts.  Neon lighting technology has been reshaped from long tubes into thin flat panels used for plasma displays and plasma television sets.Sony VAIO VGN-CS11S/W Battery

Neon tube lighting and signs

When Georges Claude demonstrated an impressive, practical form of neon tube lighting in 1910, he apparently envisioned that it would be used as a form of lighting, which had been the application of the earlier Moore tubes that were based on nitrogen and carbon dioxide discharges. Sony VAIO VGN-CS11Z/R Battery

Claude's 1910 demonstration of neon lighting at the Grand Palais (Grand Palace) in Paris lit aperistyle of this large exhibition space. Claude's associate, Jacques Fonseque, realized the possibilities for a business based on signage and advertising. By 1913 a large sign for the vermouth Cinzano illuminated the night sky in Paris, Sony VAIO VGN-CS120J/P Battery

and by 1919 the entrance to the Paris Opera was adorned with neon tube lighting.

Neon signage was received with particular enthusiasm in the United States. In 1923, Earle C. Anthony purchased two neon signs from Claude for his Packard car dealership in Los Angeles, California; these literally stopped traffic.Sony VAIO VGN-CS120J/Q Battery

Claude's US patents had secured him a monopoly on neon signage, and following Anthony's success with neon signs, many companies arranged franchises with Claude to manufacture neon signs. In many cases companies were given exclusive licenses for the production of neon signs in a given geographical area; Sony VAIO VGN-CS120J/R Battery

by 1931, the value of the neon sign business was $16.9 million, of which a significant percentage was paid to Claude Neon Lights, Inc. by the franchising arrangements. Claude's principal patent expired in 1932, which led to a great expansion in the production of neon signage. Sony VAIO VGN-CS190JTB Battery

The industry's sales in 1939 were about $22.0 million; the expansion in volume from 1931 to 1939 was much larger than the ratio of sales in the two years suggests.

Rudi Stern has written, "The 1930s were years of great creativity for neon, a period when many design and animation techniques were developed. ... Sony VAIO VGN-CS190JTP Battery

Men like O. J. Gude and, in particular, Douglas Leigh took neon advertising further than Georges Claude and his associates had ever envisioned. Leigh, who conceived and created the archetypal Times Square spectacular, experimented with displays that incorporated smells, fog, and sounds as part of their total effect. ... Sony VAIO VGN-CS190JTQ Battery

Much of the visual excitement of Times Square in the thirties was a result of Leigh's genius as a kinetic and luminal artist." Major cities throughout the United States and in several other countries also had elaborate displays of neon signs. Events such as the Chicago Century of Progress Exposition (1933–34), Sony VAIO VGN-CS190JTR Battery

the Paris World's Fair (1937) and New York World's Fair (1939) were remarkable for their extensive use of neon tubes as architectural features. Stern has argued that the creation of "glorious" neon displays for movie theaters led to an association of the two, "One's joy in going to the movies became inseparably associated with neon."Sony VAIO VGN-CS190JTW Battery

The Second World War (1939–1945) arrested new sign installations around most of the world. Following the war, the industry resumed. Marcus Thielen writes of this era, "...after World War II, government programs were established to help re-educate soldiers.Sony VAIO VGN-CS190NAB Battery

The Egani Institute (New York City) was one of few schools in the country that taught neon-trade secrets. The American streamlined design from the 1950s would be unimaginable without the use of neon." The development of Las Vegas, Nevada as a resort city is inextricably linked with neon signage; Sony VAIO VGN-CS190NAC Battery

Tom Wolfe wrote in 1965, "Las Vegas is the only city in the world whose skyline is made neither of buildings, like New York, nor of trees, like Wilbraham, Massachusetts, but signs. One can look at Las Vegas from a mile away on route 91 and see no buildings, no trees, only signs. But such signs! They tower. Sony VAIO VGN-CS190NAD Battery

They revolve, they oscillate, they soar in shapes before which the existing vocabulary of art history is helpless."

Overall, however, neon displays became less fashionable, and some cities discouraged their construction with ordinances. Nelson Algren titled a 1947 collection of his short stories The Neon Wilderness.Sony VAIO VGN-CS190NBB Battery

Margalit Fox has written, "... after World War II, as neon signs were replaced increasingly by fluorescent-lighted plastic, the art of bending colored tubes into sinuous, gas-filled forms began to wane."  A dark age persisted at least through the 1970s, when artists adopted neon with enthusiasm; in 1979 Rudi Stern published his manifesto, Let There Be Neon.Sony VAIO VGN-CS190NCA Battery

Marcus Thielen wrote in 2005, on the 90th anniversary of the US patent issued to Georges Claude, "The demand for the use of neon and cold cathode in architectural applications is growing, and the introduction of new techniques like fiberoptics and LED — into the sign market have strengthened, rather than replaced, neon technology. Sony VAIO VGN-CS190NCB Battery

The evolution of the 'waste' product neon tube remains incomplete 90 years after the patent was filed."

Neon glow lamps and plasma displays

In neon glow lamps, the luminous region of the gas is a thin, "negative glow" region immediately adjacent to a negatively charged electrode (or "cathode"); Sony VAIO VGN-CS190NCC Battery

the positively charged electrode ("anode") is quite close to the cathode. These features distinguish the lamps from the much longer and brighter luminous regions in neon tube lighting; technically, the latter correspond to a "positive column" in the discharge that is absent in the lamps. Sony VAIO VGN-CS50B/W Battery

The energy dissipation in the lamps when they are glowing is very low (about 0.1 W), hence the distinguishing term cold-cathode lighting.

Some of the applications of neon lamps include:

  • Pilot lamps that indicate the presence of electrical power in an appliance or instrument (e.g. an electric coffee pot or power supply).Sony VAIO VGN-CS51B/W Battery
  • Decorative (or "figural") lamps in which the cathode is shaped as a flower, animal, etc.. The figures inside these lamps were typically painted with phosphorescent paints to achieve a variety of colors.
  • Active electronic circuits such as electronic oscillators, timers, memory elements, etc..
  • Intricate electronic displays such as the Nixie tube (see photograph). Sony VAIO VGN-CS52JB/W Battery

The small size of the negative glow region of a neon lamp, and the flexible electronic properties that were exploited in electronic circuits, led to the adoption of this technology for the earliest plasma panel displays. The first monochrome dot matrix plasma panel displays were developed in 1964 at the University of Illinois for the PLATO educational computing system. Sony VAIO VGN-CS60B/P Battery

They had the characteristic color of the neon lamp; their inventors, Donald L. Bitzer, H. Gene Slottow, and Robert H. Wilson, had achieved a working computer display that remembered its own state, and did not require constant refreshing from the central computer system. Sony VAIO VGN-CS60B/Q Battery

The relationship between these early monochrome displays and contemporary, color plasma displays and televisions was described by Larry F. Weber in 2006, "All plasma TVs on the market today have the same features that were demonstrated in the first plasma display which was a device with only a single cell. Sony VAIO VGN-CS60B/R Battery

These features include alternating sustain voltage, dielectric layer, wall charge, and a neon-based gas mixture." As in colored neon lamps, plasma displays use a gas mixture that emits ultraviolet light. Each pixel has a phosphor that emits one of the display's base colors.Sony VAIO VGN-CS61B/P Battery

Neon lighting and artists in light

The mid to late 1980's was a period of resurgence in neon production. Sign companies developed a new type of signage called channel lettering, in which individual letters were fashioned from sheet metal.Sony VAIO VGN-CS61B/Q Battery

While the market for neon lighting in outdoor advertising signage has declined since the mid 20th Century, in recent decades neon lighting has been used consciously in art, both in individual objects and integrated into architecture. Frank Popper traces the use of neon lighting as the principal element in artworks to Gyula Košice's late 1940s work in Argentina.Sony VAIO VGN-CS61B/R Battery

Among the later artists whom Popper notes in a brief history of neon lighting in art are Stephen Antonakos, the conceptual artists Joseph Kosuth and Bruce Nauman, Martial Raysse, Chryssa, Piotr Kowalski, and François Morellet.

Several museums in the United States are now devoted to neon lighting and art, including the Museum of Neon Art (founded by neon artist Lili Lakich, Los Angeles, 1981),Sony VAIO VGN-CS62JB/P Battery

the Neon Museum (Las Vegas, founded 1996), the American Sign Museum (Cincinnati, founded 1999), and the Neon Museum of Philadelphia (founded by Len Davidson, Philadelphia, 1985). These museums restore and display historical signage that was originally designed as advertising, in addition to presenting exhibits of neon art.Sony VAIO VGN-CS62JB/Q Battery

Several books of photographs have also been published to draw attention to neon lighting as art. In 1994, Christian Schiess has published an anthology of photographs and interviews devoted to fifteen "light artists".

nixie tube is an electronic device for displaying numerals or other information. Sony VAIO VGN-CS62JB/R Battery

The glass tube contains a wire-mesh anode and multiple cathodes. In most tubes, the cathodes are shaped like numerals. Applying power to one cathode surrounds it with an orange glow discharge. The tube is filled with a gas at low pressure, usually mostly neon and often a little mercury and/or argon, in a Penning mixture.Sony VAIO VGN-CS71B/W Battery

Although it resembles a vacuum tube in appearance, its operation does not depend on thermionic emission of electrons from a heated cathode. It is therefore called a cold-cathode tube (a form of gas filled tube), or a variant of neon lamp. Such tubes rarely exceed 40 °C (104 °F) even under the most severe of operating conditions in a room at ambient temperature.Sony VAIO VGN-CS72JB/W Battery

The most common form of nixie tube has ten cathodes in the shapes of the numerals 0 to 9 (and occasionally a decimal point or two), but there are also types that show various letters, signs and symbols. Because the numbers and other characters are arranged one behind another, each character appears at a different depth, giving Nixie based displays a distinct appearance.Sony VAIO VGN-CS90HS Battery

A related device is the pixie tube, which uses a stencil mask with numeral-shaped holes instead of shaped cathodes. Some Russian nixies, e.g. the IN-14, used an upside-down digit 2 as the digit 5, presumably to save manufacturing costs as there is no obvious technical or aesthetic reason.Sony VAIO VGN-CS90NS Battery

Each cathode can be made to glow in the characteristic neon red-orange color by applying about 170 volts DC at a few milliamperes between a cathode and the anode. The current limiting is normally implemented as an anode resistor of a few tens of thousands of ohms. Sony VAIO VGN-CS90S Battery

Nixies exhibit negative resistance and will maintain their glow at typically 20 V to 30 V below the strike voltage. Some color variation can be observed between types, caused by differences in the gas mixtures used. Longer-life tubes that were manufactured later in the nixie timeline have mercury added to reduce sputtering  resulting in a blue or purple tinge to the emitted light. Sony VAIO VGN-CS91HS Battery

In some cases, these colors are filtered out by a red or orange filter coating on the glass.

Applications and lifetime

Nixies were used as numeric displays in early digital voltmeters, multimeters, frequency counters and many other types of technical equipment.Sony VAIO VGN-CS91NS Battery

They also appeared in costly digital time displays used in research and military establishments, and in many early electronic desktop calculators, including the first: the Sumlock-Comptometer ANITA Mk VII of 1961 and even the firstelectronic telephone switchboards. Sony VAIO VGN-CS91S Battery

Later alphanumeric versions in fourteen segment display format found use in airport arrival/departure signs and stock ticker displays. Some elevators used nixies to display floor numbers.

Average longevity of nixie tubes varied from about 5,000 hours for the earliest types, to as high as 200,000 hours or more for some of the last types to be introduced. Sony VAIO VGN-CS92DS Battery

There is no formal definition as to what constitutes "end of life" for nixies, mechanical failure excepted. Some sources (Weston 1968, p. 340) suggest that 50% reduction in emitted light would not be acceptable; however cathode poisoning resulting in incomplete digit display, while generally not preventing the tube from being used, may also be considered unacceptable. Sony VAIO VGN-CS92JS Battery

Nixie tubes are susceptible to multiple failure modes, including

  • simple breakage,
  • cracks and hermetic seal leaks allowing the atmosphere to enter,
  • cathode poisoning preventing part or all of one or more characters from illuminating,
  • increased striking voltage causing flicker or failure to light, Sony VAIO VGN-CS92XS Battery
  • sputtering of electrode metal onto the glass envelope blocking the cathodes from view,
  • internal open or short circuits which may be due to physical abuse or sputtering.Sony VAIO VGN-FW11E Battery

Driving nixies outside of their specified electrical parameters will accelerate their demise, especially excess current, which increases sputtering of the electrodes. A few extreme examples of sputtering have even resulted in complete disintegration of nixie tube cathodes.Sony VAIO VGN-FW11L Battery

As testament to their longevity, and that of the equipment which used them, in 2006 several suppliers still provide common nixie tube types as service replacement parts, new in original packaging. Equipment with nixie tube displays in excellent working condition is still plentiful, though much of it has been in frequent use for 30–40 years or more. Sony VAIO VGN-FW11M Battery

Such items can easily be found as surplus and obtained at very little expense. In the former Soviet Union, nixies were still being manufactured in volume in the 1980s, so Russian and Eastern European nixies are still available.Sony VAIO VGN-FW11S Battery

One advantage of the Nixie tube is that its cathodes are typographically designed, shaped for legibility. In most types, they are not placed in numerical sequence from back to front, but arranged so that cathodes in front of the one that is lit obscure it minimally. The digit sequence is rarely given; one arrangement is 6 7 5 8 4 3 9 2 0 1 from front (6) to back (1).Sony VAIO VGN-FW11ZU Battery

The early Nixie displays were made by a small vacuum tube manufacturer called Haydu Brothers Laboratories, and introduced in 1955 by Burroughs Corporation, who purchased Haydu and owned the name Nixie as a trademark. The name Nixie was derived by Burroughs from "NIX I", an abbreviation of "Numeric Indicator eXperimental No. 1."Sony VAIO VGN-FW139E/H Battery

Similar devices that functioned in the same way were patented in the 1930s, and the first mass-produced display tubes were introduced in 1954 by National Union Co. under the brand name Inditron. However, their construction was cruder, their average lifetime was shorter, and they failed to find many applications due to their complex periphery.Sony VAIO VGN-FW140AE Battery

Burroughs even had another Haydu tube that could operate as a digital counter and directly drive a Nixie tube for display. This was called a "Trochotron", in later form known as the "Beam-X Switch" counter tube; another name was "magnetron beam-switching tube", referring to their similarity to a cavity magnetron. Sony VAIO VGN-FW140D Battery

Trochotrons were used in the UNIVAC 1101 computer, as well as in clocks and frequency counters.

The first trochotrons were surrounded by a hollow cylindrical magnet, with poles at the ends. The field inside the magnet had essentially-parallel lines of force, parallel to the axis of the tube. Sony VAIO VGN-FW140E Battery

It was a thermionic vacuum tube; inside were a central cathode, ten anodes, and ten "spade" electrodes. The magnetic field and voltages applied to the electrodes made the electrons form a thick sheet (as in a cavity magnetron) that went to only one anode.Sony VAIO VGN-FW140E/H Battery

Applying a pulse with specified width and voltages to the spades made the sheet advance to the next anode, where it stayed until the next advance pulse. Count direction was not reversible. A later form of trochotron called a Beam-X Switch replaced the large, heavy external cylindrical magnet with ten small internal metal-alloy rod magnets which also served as electrodes.Sony VAIO VGN-FW140E/W Battery

Glow-transfer counting tubes, similar in essential function to the Trochotrons, had a glow discharge on one of a number of main cathodes, visible through the top of the glass envelope. Most used a neon-based gas mixture and counted in base-10, but faster types were based on argon, hydrogen, or other gases, and for timekeeping and similar applications a few base-12 types were available. Sony VAIO VGN-FW140FE Battery

Sets of "guide" cathodes (usually two sets, but some types had one or three) between the indicating cathodes moved the glow in steps to the next main cathode. Types with two or three sets of guide cathodes could count in either direction. A well-known trade name for glow-transfer counter tubes in the United Kingdom was Dekatron.Sony VAIO VGN-FW140N Battery

Types with connections to each individual indicating cathode, which enabled presetting the tube's state to any value (in contrast to simpler types which could only be directly reset to zero or a small subset of their total number of states), were trade named Selectrontubes.Sony VAIO VGN-FW140N/W Battery

Some Nixie-like displays made by other firms were called by various trademarked names including DigitronInditronand Numicator. A proper generic term is "cold cathode neon readout tube", though the phrase "nixie tube" quickly entered the vernacular as a generic name. Sony VAIO VGN-FW145E Battery

Hundreds of variations of this design were manufactured by many firms, from the 1950s until the 1990s.

Alternatives and successors

Other numeric display technologies concurrently in use included backlit columnar transparencies, a.k.a. "thermometer displays", light pipe, Sony VAIO VGN-FW145E/W Battery

rear-projection and edge-lit lightguide displays (all using individual incandescent or neon light bulbs for illumination); Numitron incandescent filament readouts; and vacuum fluorescent display tubes. Before nixie tubes became prominent, most numeric displays were electromechanical, Sony VAIO VGN-FW160AE Battery

using stepping mechanisms to display digits either directly by use of cylinders bearing printed numerals attached to their rotors, or indirectly by wiring the outputs of stepping switches to indicator bulbs. Later, a few vintage clocks even used a form of stepping switch to drive nixie tubes.Sony VAIO VGN-FW160D Battery

Nixie tubes were superseded in the 1970s by light-emitting diodes (LEDs) and vacuum fluorescent displays (VFDs), often in the form of seven-segment displays. The VFD used a hot filament to emit electrons and phosphor-coated anodes, like a cathode ray tube, shaped to represent segments of a digit, pixels of a graphical display, or complete letters, symbols, or words. Sony VAIO VGN-AW90S Battery

Whereas nixies typically require 180 volts to illuminate, VFDs only require relatively low voltages to operate, making them easier and cheaper to use. VFDs have a simple internal structure, resulting in a bright, sharp, and unobstructed image. Unlike nixies, the glass envelope of a VFD is evacuated rather than being filled with a specific mixture of gases at low pressure.Sony VAIO VGN-AW90US Battery

Specialized high voltage driver chips such as the 7441/74141 were available to drive nixies. LEDs were better suited to the low voltages that integrated circuitsused, which was an advantage for devices such as pocket calculators, digital watches, and handheld digital measurement instruments. Sony VAIO VGN-AW91CDS Battery

Also, LEDs were much smaller and sturdier, without a fragile glass envelope. LEDs had lower power consumption than both VFDs and Nixie tubes.

Revival

Citing dissatisfaction with the aesthetics of modern digital displays and a nostalgic fondness for the styling of obsolete technology, significant numbers of electronics enthusiasts in recent years have shown interest in reviving nixies.Sony VAIO VGN-AW91CJS Battery

Unsold tubes that have been sitting in warehouses for decades are being brought out and used, the most common application being in homemade digital clocks. This is somewhat ironic, since during their heyday, nixies were generally considered too expensive for use in mass-market consumer goods such as clocks. Sony VAIO VGN-AW91CYS Battery

This recent surge in demand has caused prices to rise significantly, particularly for large tubes. The largest type known to be in the hands of collectors, the Rodan CD-47/GR-414 (220 mm [8.7 in] tall),  have been sold for hundreds of dollars each, but these are extremely rare and only found in a few areas of the world by persistent and fortunate seekers.Sony VAIO VGN-AW91DS Battery

Prices for other large types displaying digits over 25 mm (1 in) tall have risen by double, triple or more between 1998 and 2005.

In addition to the tube itself, another important consideration is the relatively high-voltage circuitry to drive the tube.Sony VAIO VGN-FW160E Battery

The original 7400 series drivers ICs such as the 74141 BCD decoder driver (or its Russian equivalent the K155ID1) have long since been out of production and are rarer than NOS tubes. However modern bipolar transistors with high voltage ratings are now available cheaply,Sony VAIO VGN-FW160E/H Battery

such as MPSA92 or MPSA42 - an unusual example where an original IC design has been replaced by discrete transistors.Sony VAIO VGN-FW160F/E Battery,Sony VAIO VGN-FW170J/H Battery,Sony VAIO VGN-FW180AE Battery,Sony VAIO VGN-FW180D Battery,Sony VAIO VGN-FW180E Battery,Sony VAIO VGN-FW180E/H Battery,Sony VAIO VGN-FW180FU Battery

 

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