The development and commercialization of the incandescent light was soon allowing the illumination of factories, commercial areas, streets, and homes of the wealthy. During the first couple decades of the 20th century the electric infrastructure started to grow from the wealthiest areas to eventually arrive in the poorer neighborhoods and outside cities. Arriving in U.S. farm areas during the 1930’s, the electricity allowed the replacement of the dangerous and dim kerosene lanterns so often used previous to the electric light. The incandescent light and the electric power infrastructure which made artificial lighting a common everyday thing also made huge changes in domestic life as electrical appliances and tools became available.
The next big break in artificial lighting came in 1926 when the first truly successful fluorescent lamps came into being. However, even prior to the major modern developments in the incandescent light, there were experiments and was interest in the possibility that fluorescence, as seen in rocks and other things in nature could, somehow, be duplicated on demand. During the middle of the 1800’s it was discovered that partially evacuated glass vessels could emit a radiant glow when an electrical current was passed through them. The Irish scientist, Sir George Stokes, of the University of Cambridge was one of the first to discover and explain the science behind the phenomenon. He actually coined the word fluorescence in regard to the phenomenon, using the mineral fluorite as the basis for the word as the mineral fluorite has a tendency to glow due to impurities in the structure.
In 1856, German glassblower Heinrich Geissler developed a vacuum pump which was capable of evacuating a glass vessel to an extent never before attained. He developed a partially evacuated glass tube with a metal electrode at each end. It was called the Geissler tube and was the first gas discharge lamp. The application of high voltage to the electrodes made the tube create a soft glowing light. By introducing different chemicals into the tubes, they were made to glow in differing colors, and these tubes became popular for entertainment purposes. In 1859 Alexandre Edmond Becquerel determined that certain compounds gave off light when placed in a Geissler tube. He pioneered the thin coatings of luminescent materials on the surfaces of the tubes. These early tubes worked but were very short lived.
As better vacuum apparatus was developed, the Geissler tubes continued to be further improved. The most important development occurred in a tube developed by William Crookes who used a very efficient mercury evacuation pump developed by Herman Sprengel to create a tube that eventually led to the discovery of X-rays in 1885 by Wilhelm Roentgen and discovery of the electron by J.J. Thompson in 1897. However, in regard to light, the Crookes tube, as it eventually came to be called, did not produce very good light because the vacuum was so extreme that it lacked the trace amounts of gasses needed to create the electrically energized luminescence.
Thomas Edison was also one who briefly experimented with fluorescent lighting in an attempt to prove its commercial viability. In 1896 he created a fluorescent light which contained a coating of calcium tungstate which was excited by X-rays. This light did receive one of his many patents but was never put into production. Due to the success of the incandescent light and the short life of all the Geissler tube lights, Edison had very little reason to pursue alternate forms of electrical lighting. Nikola Tesla also toyed with fluorescence type lighting experiments during the 1890’s. He developed high frequency powered fluorescent lighting which exhibited a greenish glow but it was never a commercial success.
Even though Edison had little interest in the fluorescent lighting idea, one of his former employees, Daniel McFarrlan Moore, in 1895, demonstrated that tubes filled with carbon dioxide could produce white light and ones filled with nitrogen could emit pinkish light. Moore, after many years, was successful in extending the operating life of the lights by inventing a method to maintain a constant gas pressure within the tube. Although it was more expensive and complicated than the incandescent lights, it did emit a light which was closer to natural daylight and it was more efficient. Despite the expense and complicated operation, starting in 1904, the lighting systems began being installed in many stores and office complexes. This case of the first commercially successful fluorescent lighting is what drove General Electric to start developing improvements of the incandescent light. Also in 1904, European inventors developed the first tungsten filament which improved the efficacy and lifespan of the incandescent light. This development was further enhanced by Irving Langmuir’s discovery that adding an inert gas to the bulb would double the life of the light. General Electric, using those two developments became the preeminent manufacturer of incandescent bulbs at the time. Those improvements helped negate the advantages formerly held by Moore’s fluorescent lighting. Despite the downfall of Moore’s fluorescent lamp, GE did decide to purchase the relevant patents in 1912. That move proved to be invaluable when the company dove heavily into fluorescent lighting more than twenty years later.
This blog is a multi-part writing which will touch on the evolution of artificial lighting and will be continued in the upcoming weeks. In the meantime, if you need help with your LED lighting projects, please feel free to call Polar Ray at 303-494-5773 and speak with a lighting consultant.