"Genius is ninety-nine percent perspiration and one percentinspiration."
Whatever the percentages, the concept is much the same for inventors today as forEdison. But circumstances have changed. Work is more often done in groups in largelaboratories; scientific training is essential; equipment is complex and expensive. Here,we examine some of the differences and similarities between inventing Edison's lamp,and inventing six recent lighting devices.
Tungsten Halogen: Working in a Modern Industrial Laboratory Edison assembled a team of talented assistants for his Menlo Park "inventionfactory." But he remained the guiding force behind the light bulb effort. From the initialexperiments, through design of production equipment, to selling the lamp and itselectrical infrastructure, Edison ran the show. Today, most lamps pass from onespecialist or group of specialists to another as the original idea becomes a commercialproduct. Rarely does one individual oversee the entire process. In 1950, at General Electric's Nela Park facility, Alton Foote led an effort to design anew heat lamp using a small tube of fused quartz rather than a large glass bulb. Footefound that quartz could withstand high heat, but the lamps blackened too quickly to be ofuse. Tungsten evaporated from the filament and settled on the inside wall of the tube,darkening the lamp. Machinist turned inventor Elmer Fridrich, with the help of Emmett Wiley, placedsome iodine in a quartz lamp and "Eureka! we put it on and instant success ... it was justbeautiful." As seen in the image below, iodine cleared the tungsten atoms from the tube wall and returned them to thefilament. Despite the initial success, follow-up experiments proved frustrating as somelamps worked and some that appeared identical failed. In early 1954 chemist Edward Zubler was assigned to find out just what washappening inside the lamps, and in 1955 engineer Frederick Mosby transferred into theproject to begin designing a marketable product. Fridrich and Wiley began playing areduced role. After about three years of experiments Zubler and Mosby worked out theunique chemical and structural requirements of the lamp, some of which called for newprocedures. For example, the tungsten filament wire had to be unusually pure, and thisrequired the participation of engineers at GE's "wire plant." A "pilot production" facility was set up to provide hand-made experimental lampsand by mid-1958 the team began to feel confident. As Mosby recalled, "Once management decided that we were ready to go beyond the piloting operation, we then called in our manufacturing people. They came in and looked at the lamp and decided what equipment we had to have in order to make this lamp at higher speeds, so prime responsibility went out of our hands at that time. We worked very closely with the manufacturing people, but it became their responsibility to get the equipment designed and made to put into our factories for expanded production." In 1959, the tungsten halogen lamp was ready to emerge from the lab, bringingmore new players into the process. Application engineers designed ways to use thelamps. Marketers began crafting sales pitches and researching needs that the newlamps might meet. This team approach has become typical of modern lamp invention.
Metal Halide: The Value of Scientific Training Edison never considered himself a scientist and cared little for theoretical studies.Trial and error experiments gave him the working knowledge he needed, and if somehigher math was called for he had Francis Upton on the payroll. Modern lamp inventorshave the knowledge inherited from people like Edison, but they have also inheritedcomplex problems not given to easy solutions. Inventing a lamp today calls for advancedscientific and engineering training, both to define problems and to use the highlyspecialized equipment needed to find solutions. As early as 1912 Charles Steinmetz had placed metal halide compounds in mercurylamps hoping to improve the lamps' blue-green color. Iodine, bromine and chlorine areall elements known as "halogens" and react chemically with metals to form salts. Thephysics of electrical discharges and the chemistry of metal halides turned out to be quitecomplex, and practical lamps were not made until the late 1950s. By the 1950s, mercury vapor lamps were common and the subject of muchresearch. In West Germany, Otto Neunhoeffer and Paul Schultz explored the use ofhalogens to combat electrode evaporation. Bernard Kühl and Horst Krense alsotried halogens in a lamp and filed for a patent in August 1960. However, Osram hadintroduced an improved mercury lamp (designated H-33) without halides in 1959. The H-33 lasted longer and was more efficient than older designs, and may have temperedcommercial willingness to quickly introduce yet another improved mercury lamp. 
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At this same time, American physicist Gilbert Reiling was also experimenting withmetal halides and mercury lamps. His work at General Electric's Research Laboratoryinvolved a mix of theoretical studies and experimentation. Reiling was able to bring ahigh level of expertise to bear on the problem. "I had 11 years of college mathematics,from topography to matrices to tensor [states] - everything you could possibly mention inthe field of mathematics, and you need that for the physics. I had made somethermodynamic calculations that showed that, with sodium iodide, the iodine was sopowerful that sodium would not attack the quartz [envelope]. That's what so manypeople worried about, that these alkali metals were just going to chew up the envelope,but it turned out that the thermodynamics showed that it wouldn't, and it was that ideathat really made this work." Reiling's experiments with sodium and thallium (see lamps above) were promising enough that in June1960 he reported to GE, "these lamps appear to have a higher luminous efficiencythan the mercury lamp and the possibility for better color rendition." In September thelab's research director C. Guy Suits wrote to GE's Chairman Ralph Cordiner to tell himof the new lamp. Suits reported that, although the lamp produced white light "through acomplex mechanism which our scientists are still studying in detail,... it now appearsthat little change will be required in manufacturing the new lamps other than simplyadding a scientifically determined 'pinch' of the optimum compound." GE publiclyannounced the metal halide lamp in late 1962 and used it at the 1964 World's Fair.
High Pressure Sodium: Studying Materials Edison spent almost a year trying to develop a platinum filament for his lamp. Thematerial would not burn up in air, but making it give light without melting proved difficult.Eventually Edison return to experimenting with carbon filaments, and he and his teambaked hundreds of materials before settling on bamboo for their commercial product.The choice of materials is no less important today. Modern inventors simply have manymore possibilities to chose from due to the great number of artificial materialsunavailable a century ago. Low-pressure sodium (LPS) lamps were developed in Europe early in the 1930s. Because sodium was very corrosive, LPS lamps needed special glass and very stabletemperatures to operate. These factors led to complex glass-work, Dewar-typehousings, and large fixtures. Research in the 1920s indicated that increasing thesodium's pressure would improve the lamps' poor color, but no practical material couldbe found that resisted sodium corrosion at the higher pressures. After World War II, the GE Research Laboratory in Schenectady began a programto explore the properties of ceramics. Under the direction of chemist Joseph Burke, theprogram was designed to provide an understanding of ceramic processes. There was noparticular product goal in mind, just fundamental research into a little known area. In 1955 Robert Coble, a recent graduate from M.I.T., joined the team. A series ofexperiments ensued with polycrystalline aluminum oxide (PCA). Coble addedmagnesium to the mix, making a material Burke described as "more nearly transparentthan had ever been hoped for. Actually, it was more nearly translucent. ... the materialappears similar to a slightly frosted glass–but light transmission is from 90-95%." Metallurgists and ceramicists worked on improving processing techniques needed toproduce the new material (now called "Lucalox" for TranslucentAluminumOxide) consistently, mainly by determining themanufacturing parameters. George Inman, a senior manager of GE's Nela Park lightingworks in Cleveland heard of the PCA research during a trip to Schenectady in 1956 anddirected engineer William Louden to begin assessing the possibilities of making a newlamp. In late 1957, Inman sent chemical engineer Nelson Grimm to Schenectady tolearn about Lucalox and its manufacture. Grimm returned to Nela Park and establisheda "pilot-plant scale operation" that began providing tubes of the translucent material toNela's lamp designers in 1958. 
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Physical chemist Kurt Schmidt began experimenting with different fill-gasses and inAugust 1959 filed for a patent on "Metal Vapor Lamps" that included sodium. Still, thelamps were not ready for sale. A difficult problem lay in sealing the ceramic tubes, sincethey could not be pinched shut like hot glass. Few sealing materials would stick to thenew ceramic, and those that did needed to withstand the high operating temperaturesand pressures of the lamp. The first seals that we made to Lucalox with metal were very short lived and weexperimented for a long time with various methods of sealing. We got life out to 2000hours, and at that point everybody began to recognize that we had something thatmight be commercially feasible." Niobium was chosen for the seal and made into a capthat expanded at nearly the same rate as aluminum oxide. However, niobium was afairly exotic element, and new methods of working it had to be devised. Also, a materialhad to be found to serve as a "frit" (or caulking) between the niobium cap and theequally exotic ceramic tube. In 1962 GE unveiled the new high-pressure sodium (HPS) lamp. A reportercovering the unveiling noted some bantering between Louden and Schmidt.
" 'He was destroying things as soon as they were made,' said the electricalengineer."
" 'He couldn't make them tough enough,' said the physicist." Though reported as a joking exchange, the underlying situation was serious. TheHPS lamp was not sold until 1965 and was redesigned in 1967. Continued materialsresearch since that time has resulted in: clear ceramic tubes (Westinghouse &Corning, 1976); very high pressure lamps (Philips 1986); and "unsaturated lamps"(Philips, Sylvania 1993). In 1997, ceramic tubes were adapted to metal halide lamps.
Compact Fluorescent: The Challenge of Manufacturing Inventing a product often calls for inventing manufacturing equipment andprocesses. Many Edison patents described improved ways of making lamps. To achievehis price goals, Edison needed mass-produced light bulbs rather than a hand-craftedproduct. Desire to boost production machine efficiency has often motivated designchanges in lamps. Conversely, new lamps requiring complex production techniqueshave often been shelved as uneconomical. In the 1970s, many inventors proposeddesigns for efficient compact fluorescent lamps (CFL). Most of these designs worked inthe lab. However, most were considered too expensive to mass-produce. Below are a few of those designs. John Campbell (General Electric) "Sequential Switching Lamp," 1972. (See U.S.patent # 3,609,436.) Campbell's work on high-frequency fluorescent lamp ballasts in the1950s led to this design. The lamp contained multiple electrodes, each activated in quicksequence in its own arc-path. The switching circuitry and the glass-work were deemedtoo complex for mass production. William Roche (GTE-Sylvania) "Short Arc Lamp," 1974. (See U.S. patent #3,849,699.) Roche described this lamp in a 1996 interview: "In some of the early dayswe were trying to develop a ballast-less fluorescent lamp. How could we compact thelamp and eliminate the ballast? [We thought] maybe the ballast wasn't all that bad if wecould miniaturize it and tuck it away in the base. This lamp's construction had a filamentrunning the length of the lamp to serve as an ignition aid. The problem is that they werenot efficient, the shortness of the arc was one major problem. [In] the short-arc,high-current was required to generate the power, and the high-current in the ballastcreated losses within the electronics. It proved not to be feasible." John Anderson (GE) "Solenoidal Electric Field Lamp" and Donald Hollister (LightingTechnology Corporation) "Litek Lamp," mid 1970s. Electrodes are responsible for muchof the energy lost in a fluorescent lamp and are usually the first part of the lamp to fail.Both Anderson and Hollister designed small "electrodeless" lamps that operated withhigh-frequency radio waves instead of electrodes. The electronic components availableat the time were expensive and generated too much heat, and neither lamp made it tomarket. However, in the 1990s, Philips, GE, and Osram-Sylvania all began sellingelectrodeless fluorescent lamps. R. Gaines Young (Westinghouse), and Harald Whiting (GE) "Partitioned Lamps,"late 1970s. Due to the physics of fluorescent lamps, longer tubes mean higher energyefficiency. One way around this is to create a maze-like path for the electrical arc usingglass partitions within a short bulb. Young, Witting, and others patented many variationson this theme, but the glass-work for all proved too complex for high-speedmanufacture. Jan Hasker (Philips) "Recombinant Structure Lamp," 1976. (See U.S. patent#4,101,185). Hasker developed compact fluorescent lamps filled very loosely with glassfibers. These fibers altered the properties of the electrical current flowing inside thelamp, boosting light output without reducing energy efficiency. Though his experimentswere promising, Hasker wrote that, "before any practical applications can be realized,technological problems concerning the manufacture of the recombination structure ...should be solved." Hasker's was only one of the CFL designs being developed byPhilips, and the company chose not to pursue the lamp, partly due to manufacturingconcerns. 
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Edward Hammer (GE) "Spiral Lamp," 1976. Hammer's idea(at left) was to take a long, thinfluorescent tube and bend it into a spiral shape. This not only allowed for a longelectrical arc, but also simulated the optical properties of a frosted incandescent lamp.Existing lamp machinery had difficulty making the fragile spiral, and GE felt that newmachinery would be too expensive, so they shelved the design. However, spiral lampsappeared on the market in 1995 as other manufacturers decided to see if the designcould be competitive.
Leo Gross and Merrill Skeist (Spellman Electronics) "Magnetic Arc-SpreadingLamp," 1980. An energized coil of wire in the middle of a cylinder-shaped lampgenerated a magnetic field. The field expanded the electrical arc inside the lamp,activating a greater area of phosphors. Prototypes included both cylindrical lamps and ahemispherical unit. According to Skeist, "we achieved 15% improved efficiency" overother CFL designs, at which point, "many companies expressed interest." But the glassenvelope proved too expensive to make. Successful designs from Philips and Westinghouse, and CFLs from othermanufacturers that followed, required substantial investment in new productionmachinery. This was a major reason why the initial price of these lamps was rather high(about $15 in the early 1980s–which would be about $30 now). Large orders fromgovernments and electric utilities, who then offered the lamps to customers at sharplyreduced prices, gave producers an incentive to make the needed investments.
Silicon Carbide: The Lone Inventor Americans hold a special place in their hearts for the "garage inventor"–someonewho, without an expensive laboratory or a large staff of assistants, proceeds to dazzleeveryone with a marvelous new gadget. Edison and his team at Menlo Park really don'tfit this image, and given the electrical equipment needed for lamp experiments neitherdid most others of that era. The training and equipment needed for inventing electriclights still serves as a hurdle that lone inventors must overcome. But a large lab is notrequired for inspiration; that can come from a high school project. Research to find a better filament has been a part of incandescent lamp historysince the beginning. Edison and many other inventors labored to find a suitablematerial. By the 1920s tungsten became the filament of choice and has remained so tothis day. As production techniques became more sophisticated, most researchers turnedto improving, rather than replacing, tungsten filaments. In 1987, John Milewski, Sr. found himself with an interesting situation. His son,Peter, had decided to investigate the electrical properties of single crystal "whiskers" ofsilicon carbide (SiC) for a high school science fair. Peter's goal was to determine if theceramic material would make good heating elements. His choice of projects wasinfluenced by his father's career. The elder Milewski (with a Ph.D. in ceramicengineering) worked at Los Alamos National Laboratory, exploring the use of SiCwhiskers as structural reinforcement for graphite objects. John Sr. began assisting his son with some excess silicon carbide left over from labexperiments. SiC could withstand 1500-1600oC, making it a goodcandidate for a heating element. As they increased the temperature, they found that thewhiskers glowed, not totally unexpected since many materials radiate light at hightemperature. What surprised them was how fast light production increased astemperature rose. They redirected the project from developing a heating element toevaluating SiC's potential as a lamp filament. Using surplus equipment purchased fromLos Alamos, father and son began making light bulbs in their living room. Though hampered by their inability to create a very high vacuum in their lamps, thecomparison of SiC to tungsten yielded interesting results. Peter's project took third placeat the science fair, but the consolation prize was U.S. Patent #4,864,186 issued to theMilewskis in 1989. By that time, Peter had entered North Carolina State University, andJohn Sr. had retired from Los Alamos and established Superkinetic Inc. with $83,000($30,000 for patents, $50,000 for equipment). John's goal was to improve thewhiskersand seek "more perfect crystals" by initiating experiments with hafnium carbide (HfC).He moved the work out of his home and into a lab at the University of New Mexico. 
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Unlike corporate researchers, Milewski had to mixfund raising with experimenting.In April 1991, he submitted sample SiC lamps like the one at right to the National Institute of Standards andTechnology (NIST) for evaluation and received a favorable review. Later that year heobtained funding from the Electric Power Research Institute (EPRI). The EPRI fundsallowed Milewski to improve his equipment and make filaments 5 microns in diameterand 3 mm long. However, SiC crystals take around 16 hours to grow, while HfC crystals take 35-40 hours.Problems arose in keeping oven conditions constant for that length of time, particularlywith the surplus equipment being used. Milewski and company were building their ownequipment or picking up surplus materials from Los Alamos and Sandia National Labs.Crystal-growth processes became the main problem standing between them andsuccess. In 1993 the EPRI money ran out, but Superkinetic was able to land a $100,000grant from the joint NIST-DOE Energy-Related Invention Program. This allowedproduction of filaments up to 7 micron diameter and 7mm length. The funding only lastedone year, however, and Milewski took a page from Edison's book by expanding researchand development in his company to include more immediately marketable products. Todate, the ceramic filament lamp remains in the laboratory.
Sulfur: Opportunity in a Non-Lighting Company George Westinghouse's company became the #2 lamp maker in the U.S., but he didnot start out making lamps. Westinghouse invented a railroad air-brake in 1867 andthen diversified into electrical railroad devices and more generalized electricalequipment including light bulbs. Invention still occasionally appears from an unlooked-for direction. A breakthrough may require an approach that runs counter to conventionalwisdom. Sometimes an answer that requires a large mental leap from an inventor closeto a technology may only be a small step for another inventor concerned with a differenttechnology. The development of a microwave-powered light bulb provides a case inpoint. In 1990 Fusion Systems was a small company with a successful, highly specializedproduct. Founded by "four scientists and an engineer," the company marketed aninnovative ultraviolet (UV) lighting system powered by microwaves. Introduced in 1976,the system found favor with industrial customers who needed a fast and efficient way tocure inks. A major brewery, for example, purchased the system for applying labels tobeer cans. In 1980 and again in 1986, engineer Michael Ury, physicist Charles Wood, and theircolleagues experimented with adapting their UV system to produce visible light.Discharge lamps have traditionally been hindered by the need for electrodes to supportan electric arc. Tungsten electrodes are most common, so materials that might erodetungsten can't be used in the lamp and care must be taken to not melt the electrodes.Fusion's UV lamp side-stepped this problem by eliminating the electrodes entirely. Microwave energy was focused on the lamp to energize the discharge. This opened theway for experiments with non-traditional materials, including sulfur. In 1980 Ury and Wood tried placing sulfur in their linear UV lamp without success. One lamp "blew up," and they shelved the idea. By 1986 they had improved the basicdesign of the UV lamp by replacing the linear tube with a rotating sphere. Ury decided totry making an electrodeless metal-halide lamp that might be useful in motion picturelighting. The design had color problems, and this project also was shelved. Ury recalled the sulfur experiments in 1990 and directed engineer Jim Dolan to testthe element in the spherical lamp. At 16:57:53 (4:57 pm) on 16 July 1990, a computerprint-out showed the inventors what they hoped for: a good visible spectrum with littleUV or infrared. They began setting up "crude" lamps in the Fusion production facility inorder to learn more about the new light source. They also tested variations ofthe bulb, such as the different diameter spheres seen here. After a year of tests, Ury learned of a new optical plastic based on the work ofLorne Whitehead at the University of British Columbia. "Light Pipes" with an internalcoating of the plastic would be a perfect way to distribute the light produced by the sulfurbulb. But a demonstration of the technology would be needed. Lee Anderson, lighting product manager at the Department of Energy heard aboutthe sulfur bulb and saw the invention's potential as an energy saver. He arranged fortwo high profile public demonstrations of the new technology: outdoors at DOE'sWashington headquarters, and inside the most visited museum in the world, theSmithsonian's National Air & Space Museum. Though he realized that failure wouldbe impossible to hide, Ury agreed to the plan. The installations proved successful, and the lighting industry began to take sulfurlamps more seriously. Commercial units have been placed on the market. While still notwidely adopted, several fixture companies have produced designs that can use thelamp. Whitehead's light-pipe technology has seen a bit more success as severalcompanies have coupled conventional metal halide lamps to them. The long termsuccess or failure of both sulfur lamps and light pipes, of course, remains to be seen.
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