Updated 25-IX-2021

Emmett H. Wiley

Emmett Wiley at work, circa 1970s 4

Emmett Hamilton Wiley was born on 6 April 1927 in Douglasville (Texas), U.S.A., to parents Charles E. and Lora A. (Hamilton) Wiley. They were part of a large family including three brothers Pete, Edward and Gene, and three sisters who later married as Christine Temple, Charlene Morris and Beth Hurt. Emmett was raised in the nearby town of Linden (Texas), where he graduated from Linden High School in 1944.

His first employment was at Red River Ordinance Depot, but due to the impending start of World War II he was soon drafted into the Army. Following military service he returned to study at the Texas College of Arts & Industries, and in 1951 completed a Master's degree in Physics.

Wiley then found employment at General Electric, first taking up work at the central laboratories in Schenectady (New York). He quickly specialised in light source technology, and relocated to GE's Nela Park facility in East Cleveland (Ohio). He remained at this location for 35 years until his retirement, and his inventive spirit led to the development of several major new product innovations. He designed and developed countless new lamps for projection and studio lighting applications, and accrued an impressive list of patents to his name. Quite apart from putting his employer in the leading position in several key markets, to this day his innovations continue to make a profound impact on the world of lighting technology. As a result he was honoured by GE on multiple occasions, including being a recipient of the coveted Charles P. Steinmetz Award in 1979. The Steinmetz Awards are given by GE to leading engineers and scientists in the company, in recognition of outstanding contributions to the company and to society in general.

Outside his career he was a past president of the Chesterland Homeowners Association and of the West Geauga Band Aids, as well as a member of the Blackbrook Audubon Society, Friends of the Library, The Native Plant Society of Texas, Linden Lions Club, and Earlyjass Society. He was an avid sailor and musician. His tailgate trombone complemented many traditional jazz bands in the Greater Cleveland area, as well as when traveling. As a member of The Rubber City Retreads, their annual venue in VT was a highlight of his love of playing traditional New Orleans style jazz.

Emmett Wiley died at 86 years of age on 8 April 2013 in Marshall (Texas), following a heart attack. He was survived by his wife of 57 years, June A. (Swartz) of Linden, their daughter Alicia Lekas, and sons Leonard and Samuel.

The Invention of the Halogen Lamp
The use of halogens in lamps was trialled as early as 1882 by Edwin Scribner of the United States Electric Lighting Company, who patented a chlorine-filled lamp which was not successful. The idea was picked up again in 1892 by John Waring of the Waring Electric Company, who patented his Novak Lamp in an attempt to circumvent the Edison patents. As the name implies that lamp contains 'no vacuum', but has a small pressure of bromine inside the bulb. This was also not successful - probably the bromine had very little effect. Although the courts declared that Waring's lamp was still in violation of the Edison patents, he managed to escape closure as the Edison patent had expired in 1894 - after which his company reverted to producing vacuum lamps.

The next noteworthy attempt to use a halogen occurred in the early 1950s following the formation of a small group, for the purpose of developing the quartz heat lamp, at the General Electric lighting headquarters of Nela Park, in E. Cleveland, Ohio. The group was under the leadership of Alton Foote, who had been charged in 1950 with developing a more compact and higher power infrared lamp for drying purposes - such as paint-baking for the automotive industry. That new lamp featured a small diameter outer envelope of fused quartz instead of the traditional larger reflector type bulb. Being a much more refractory material, quartz can withstand considerably higher temperatures than ordinary lamp glasses, which enabled it to be brought so close to the filament that even the quartz itself would become red-hot.

Linear quartz heat lamps were made in the laboratory, and sometimes it was found that they would blacken due to deposition of evaporated tungsten from the filament onto the quartz wall. Generally the rate of blackening was acceptable since the filaments of the infrared lamps ran much cooler than in normal general lighting lamps, but sometimes it became objectionable. One of the workers in the group was Elmer G. Fridrich. His assignment to that group resulted in an unforeseen benefit to the lighting industry that was to be realised many months later. Elmer had read about a refining process for exotic metals in a chemistry and metallurgy magazine; the process utilised a halogen cycle. For about six months the similarity of the refining apparatus and a vertically burning quartz heat lamp continued to intrigue Elmer. One day, after the chores of the workday had been completed (that is, following the making of a certain number of heat lamps), Elmer asked Al Foote if he could pursue an idea that he had; the idea was to put some iodine in the lamp to determine its effect. Permission was granted, and Elmer then consulted with some of the older technical personnel, including Carl Kenty. It was during these consultations that Elmer learned that halogens had been tried in carbon filament lamps before. At least two patents had been granted, as mentioned above. As a result of these consultations it was decided to proceed with the idea to add iodine to some lamps.

One of the engineers at that time was William F. Hodge. Bill was nearing retirement and in his laboratory he had an unused vacuum system that was offered to Elmer for lamp processing. In addition to allowing Elmer to use his vacuum system, Bill supplied Elmer with tubulated clear quartz heat lamps which had tungsten supports. Another colleague, Mary Jaffe, supplied Elmer with iodine. At that time Elmer had no experience in "tipping off" lamps and so he approached another colleague and friend, Emmett H. Wiley, who did have the necessary experience in tipping off lamps from a vacuum system. The stage was now set for the first quartz tungsten filament halogen lamp to be made with a measured amount of iodine. Unlike many initial attempts at invention, this one was to be, in Elmer's own words, "A howling success." The promise of a workable lamp seemed assured.

The resulting iodine-filled lamps set up a chemical transport cycle of tungsten within the lamps. Rather than the evaporated tungsten condensing on the quartz wall and leading to blackening, it reacted with free iodine to form a tungsten halide molecule. Tungsten iodide is a very volatile compound, whose boiling point is so low that it cannot condense on the hot quartz wall of the operating lamps. It therefore remains in the vapour phase, until diffusing near to the vicinity of the filament which is sufficiently hot to lead to dissociation of the tungsten iodide molecules. The result is that the tungsten atoms are redeposited back onto the filament, and the iodine atoms are freed to once again trap another tungsten atom and prevent its deposition on the bulb wall.

Fairly soon it was discovered that the themochemical processes within the halogen lamps were much more complex than initially believed, and to avoid short lifetime a better understanding and control of the lampmaking and operational processes was essential. A commercially viable lamp was only achieved after expanding the research team with Fred Mosby who worked out the necessary lamp design and manufacturing, and the physical chemist Ed Zubler who helped determine necessary iodine and oxygen levels as well as tolerable tungsten wire impurity levels, in order to achieve a reliable lamp. As time went on Fridrich and Wiley played reduced roles in the fundamental halogen lamp project, but applied their engineering skills to realise many other lamp developments.

Fridrich and Wiley applied for a patent on their basic idea of the halogen lamp on 3 March 1958, and U.S. Patent 2,883,571 was granted on 21 April 1959. One of the first lamps is illustrated below.

The First Halogen Floodlighting Lamp

The Invention of the MR16 Lamp
Following the co-invention of the halogen lamp, perhaps Wiley's second most famous development was that of the so-called MR16 lamp, featuring a miniature single-ended halogen capsule permanently cemented into a dichroic-coated pressed glass reflector. The original lamps were developed for image projection apparatus and had specular reflectors such as the example pictured below. These lamps achieved a tremendous breakthrough in projector lighting on account of their very compact size, superior optical performance and ease of use.

It was in some ways a natural development of the earlier Sylvania Tru-Beam lamp, which had pioneered the concept of a compact low voltage filament mounted at the focus of a mirrored glass reflector so as to achieve a high-precision compact optical source with reduced heat load, thanks to the use of a cold-mirror dichroic coating. Within a couple of years Sylvania went further to invent the single-ended tungsten halogen capsule and later lamps employed these instead of an incandescent filament. However the vacuum-formed thin-walled glass reflectors of the Sylvania lamps were inherently fragile, and their irregular shape did not allow for any datum point for their optical alignment within the projector. Consequently after each lamp replacement, there followed a lengthy and difficult process of re-aligning the beam of light from the new lamp into the projector's optical system.

Wiley improved on this with his invention of a similar lamp having an accurately pressed glass reflector, whose front rim was given a particular shape so as to form an optical and mechanical reference plane. By pre-focussing the lamp filament with respect to this plane during production, and introducing a novel rim-mounting system for the projectors which gripped the lamp only by this front rim, he invented what came to be known as the Rim-Mount reflector lamp concept - later classified as the 'MR' lamp type. The end contact pins of the lamp were not mechanically fixed to the projector, and electrical connection was effected via a ceramic lamp socket mounted on flexible wires. One of the first 'MR16' models is illustrated below - where the number indicates the reflector diameter in eighths of an inch. The first lamps to be marketed in 1965 were the 150W 21V ratings, including the types EJM having 40-hour life and 1½ working distance, the similar EJN having 2" working distance, and the highly loaded 15-hour EJS with 1½" working distance.

The First MR16 Projection Lamp

One of the drawbacks that was soon noted with these lamps, was that the optical precision was so great that the higher power lamps occasionally projected images of their larger filaments in the light beam, leading to a non-uniformity of luminous intensity. This was partly overcome with another invention by Robert E. Levin of Sylvania, who introduced the so-called Peened Reflector types. These featured a slight modification of the reflector surface, creating a limited amount of diffusion so as to blurr out the images of the filament and its supports. However the peened reflectors also reduced optical efficiency of the system which led to a small decrease in screen lumens. Another problem was that the tools for moulding the glass with this pattern were complex to produce, and they suffered short life due to increased wear in pressing the glass to the necessary shape.

The problem was overcome particularly elegantly when Emmet Wiley made a further refinement of his original idea, with his 1975 invention of the 'Multi-Mirror' version of the MR16 lamp. He divided the reflector surface into approximately 300 keystone-shaped facets, each of which had a flat surface. These provided just enough scattering of light to remove filament images, and avoided significant efficiency loss due to the optically flat specular surface of each facet. Moreover, the facets were easy to form by machining a series of flats onto the glass pressing tool, and the elimination of sharp angles led to increased tool life.

The First Multi-facetted MR16 Projection Lamp

For many years GE's Multi-Mirror MR16 lamps held a dominant position in the projector lamp business, but they also imparted a distinctly elegant appearance to the lamps which at once made them desirable to interior lighting designers. Particularly in Europe starting from the early 1980s, these advanced projection lamps gradually began to be specified for high-end architectural and accent lighting. As production volumes began to skyrocket the lamp prices quickly fell, and by the early 1990s it was practically impossible to walk along any shopping street of the developed world without encountering a myriad of these compact and elegant light sources in retail display lighting. Even following the gradual obsolescence of the halogen lamp in recent years, more modern high intensity discharge and even the latest LED lamps still continue to rely on Wiley's invention of the multi-facetted reflector for their optical control, and to mimic the popular appearance of their halogen predecessors.

  1. US 2,860,507 - 28-12-1954 - Area Measuring Gage (device for measuring wire surface area) - with K.R.Geiser
  2. US 2,832,661 - 18-01-1956 - Method and Apparatus for Treating Lamp Filaments (antigravity filament stabilisation for IR Quartz lamps)
  3. US 2,868,609 - 29-05-1956 - Method of Sealing and Gas Filling Electric Lamps - with V.A.Levand
  4. US 2,938,149 - 02-05-1957 - Pulse Circuit for Arc Lamp
  5. US 2,883,571 - 03-03-1958 - Electric Incandescent Lamp (basic halogen lamp patent) - with E.G.Fridrich
  6. US 2,904,714 - 16-06-1958 - Electric Lamp (type DHJ with 45° mirror below filament)
  7. US 3,025,424 - 16-06-1958 - Electric Lamp (projection having internal proximity reflector)
  8. US 2,973,443 - 10-06-1959 - Electric Incandescent Lamp (horizontal projector with proximity reflector and specially shaped baffle)
  9. US 3,093,430 - 25-04-1961 - Gas and Vapor Filling Method for Electric Lamps or Similar Devices
  10. US 3,211,942 - 20-06-1963 - Electric Incandescent Lamp (compact halogen double-ended with internal fuse)
  11. US 3,343,021 - 28-12-1964 - Electric Incandescent Projector Lamp with Heat Shield (PAR36 240V 650W with heat shield) - with G.H.Burnett
  12. US 3,325,679 - 26-02-1965 - Electric Projection Lamp having Specially Configurated Envelope (DFN with offset internal mirror)
  13. US 3,314,331 - 29-04-1965 - Photographic Projection System and Lamp (MR16 Rim-Mount Reflector)
  14. US 3,346,767 - 29-04-1965 - Integral Lens and Reflector Projection Lamp (DMJ with proximity reflector and condensing lens)
  15. US 3,826,913 - 24-05-1973 - Distributively Banded Reflector Surface for Producing Contoured Illumination Intensity (Marc 350) - with R.D.Downing
  16. US 4,021,659 - 30-10-1975 - Projector Lamp Reflector (MR16 with keystone-shape facets for reduced filament imaging)
  17. US 4,320,439 - 12-02-1979 - Compact Lamp Unit and Socket (FHZ projection lamp)
  18. US 4,319,796 - 29-10-1980 - Compact Lamp Unit and Socket (FHZ projection lamp)
  19. US 5,051,655 - 28-01-1987 - Electrodes for Single Ended Discharge Tubes (for Venture Lighting International)
  20. US 261,061D - 12-02-1979 - Design Patent - Projection Lamp Reflector (FHZ projection lamp)
  21. US 299,547D - 10-12-1985 - Design Patent - Partially Frosted Lamp (with W.R.Hellman of Advanced Lighting International)

  1. A new-type mass spectrometer employing energy-velocity selection, Doctoral Dissertaion, Texas College of Arts & Industries, 1951.

Examples of Lamps Developed by Wiley
Linear Halogen 300W Halogen DE with Fuse Offset Reflector DFN Halogen MR16 EJM Halogen MR16 ENL Metal Halide MARC-350

References & Bibliography
  1. 20th Century Inventors : Tungsten Halogen Lamp, National Museum of American History.
  2. Obitiary Emmett Wiley, Reeder-Davis Funeral Home, 2013.
  3. Find A Grave Memorial, Emmett Hamilton Wiley 1927-2013.
  4. Private Communication - Jeff Carter, September 2021. Original photograph believed to be from GE Lighting News, internal newsletter.