Incandescent light bulb

In 1802, Humphry Davy created the first electric light by passing a current through a thin strip of platinum using a battery of immense size containing 2,000 cells. The device was housed in the basement of the Royal Institution of Great Britain and served as the precedent for decades of experimentation, yet it failed to be practical because the platinum strip did not last long enough and was not bright enough for everyday use. This early demonstration proved that electricity could generate light through incandescence, but the technology remained a scientific curiosity rather than a commercial product for the next seventy-five years. Researchers continued to struggle with the fundamental problem that wires tended to melt or oxidize rapidly when exposed to air, rendering most early attempts useless for any sustained period of time. The carbon arc lamp that followed in the 1830s offered a brighter glow but emitted dangerous carbon monoxide and consumed tens of kilowatts of power, making it suitable only for lighting large public areas rather than homes. By 1840, British scientist Warren De la Rue had enclosed a coiled platinum filament in a vacuum tube, improving longevity through the removal of oxygen, but the high cost of platinum made the design commercially impractical for widespread adoption. Inventors like James Bowman Lindsay and Marcellin Jobard demonstrated working devices in the 1830s and 1840s, yet these early efforts lacked the necessary vacuum quality and electrical infrastructure to become viable alternatives to gas lighting. The search for a practical incandescent lamp was driven by the need to create a safe, reliable, and affordable source of illumination that could replace the dangerous and smelly gas lamps that dominated the 19th century. The failure of early experiments to produce a durable filament meant that the invention of the light bulb would require not just a new material, but a complete reimagining of how electricity could be generated, distributed, and utilized in the home.

The Carbon Race

Joseph Swan and Thomas Edison engaged in a fierce competition to create the first commercially viable incandescent light bulb, with Swan demonstrating a working device in 1878 and Edison achieving a successful test on the 22nd of October 1879 that lasted 13.5 hours. Swan, a British physicist and chemist, began working with carbonized paper filaments in 1850 and eventually developed a method of treating cotton to produce parchmentized thread, which allowed him to install light bulbs in homes and landmarks in England starting in 1880. His house, Underhill in Low Fell, Gateshead, became the first in the world to be lit by a light bulb, and the Savoy Theatre in London was the first public building to be lit entirely by electricity in 1881. Edison, who began serious research in 1878, initially experimented with carbon and platinum before settling on a carbonized bamboo filament that could last more than 1,200 hours, a breakthrough that secured his patent on the 27th of January 1880. The two inventors eventually merged their companies to form the Edison and Swan United Electric Company, as Edison was forced to cooperate after Swan's patents threatened his business interests. The carbon filament, while an improvement over previous attempts, suffered from a negative temperature coefficient of resistance, meaning that as the filament heated up, its resistance decreased, causing it to draw more power and heat further, creating a dangerous feedback loop. To stabilize the lamps, engineers developed metallized or graphitized filaments that had a positive temperature coefficient, similar to metallic conductors, which helped the lamps operate more reliably against minor variations in supply voltage. The carbon filament was also prone to rapid blackening of the bulb due to sublimation, a process that was exacerbated by the presence of moisture inside the bulb. In the 1880s, phosphoric anhydride was used in combination with expensive mercury vacuum pumps to remove moisture, but the process was costly and inefficient. The carbon filament era ended around 1904 when metal filaments began to displace carbon, but the carbon lamp remained the dominant technology for over two decades and laid the foundation for the modern lighting industry. The competition between Swan and Edison was not just about who could invent the bulb first, but about who could create a complete system of electric lighting that could be economically viable for widespread adoption. Edison's business success was attributed to his development of an entire integrated system, including the generation of electricity, the distribution of power, and the design of the bulb itself, which allowed his version to outstrip the others. The carbon filament was eventually replaced by metal filaments, but the lessons learned from the carbon era were crucial for the development of the more efficient and durable tungsten filaments that would follow.

Common questions

Who invented the first electric light bulb and when did Humphry Davy create it?

Humphry Davy created the first electric light in 1802 by passing a current through a thin strip of platinum using a battery of 2,000 cells. The device was housed in the basement of the Royal Institution of Great Britain but failed to be practical because the platinum strip did not last long enough. This early demonstration proved that electricity could generate light through incandescence but remained a scientific curiosity for the next seventy-five years.

When did Joseph Swan and Thomas Edison demonstrate their first working incandescent light bulbs?

Joseph Swan demonstrated a working device in 1878 and Thomas Edison achieved a successful test on the 22nd of October 1879 that lasted 13.5 hours. Swan began working with carbonized paper filaments in 1850 and installed light bulbs in homes and landmarks in England starting in 1880. Edison settled on a carbonized bamboo filament that could last more than 1,200 hours and secured his patent on the 27th of January 1880.

What year did tungsten filaments replace carbon filaments in incandescent light bulbs?

The carbon filament era ended around 1904 when metal filaments began to displace carbon. General Electric began selling incandescent light bulbs with ductile tungsten wire by 1911 after William D. Coolidge developed a method of making ductile tungsten from sintered tungsten in 1906. Tungsten has the highest available melting point and became the preferred material for its durability and efficiency.

When did Irving Langmuir patent the use of inert gas fillings in incandescent light bulbs?

Irving Langmuir found that filling a lamp with inert gas such as nitrogen or argon resulted in twice the luminous efficacy and reduced bulb blackening. He patented his device on the 18th of April 1916 and the gas fill became a standard feature in most modern bulbs. The gas reduces evaporation of the filament and keeps the tungsten below its vapor pressure to allow operation at higher temperatures.

How many lumens per watt does a typical incandescent light bulb produce compared to LED lamps?

The luminous efficacy of a typical incandescent bulb is 16 lumens per watt for a 120 volt bulb or 13 lumens per watt for a 230 volt bulb. This is significantly lower than the 100 lumens per watt for typical white LED lamps. Less than 5% of the energy consumed by an incandescent light bulb is converted into visible light and the rest is released as heat.

When did the Ribbon Machine begin mass production of incandescent light bulbs at Corning Glass Works?

The Ribbon Machine was installed in 1926 in Corning's Wellsboro, Pennsylvania factory and surpassed any previous attempts to automate bulb production. By 1939 the machine was producing 1,000 bulbs per minute and could produce 50,000 to 120,000 bulbs per hour. The automation of bulb manufacturing allowed for the production of bulbs at a fraction of the cost of hand-blown bulbs.

The Metal Revolution

The transition from carbon to metal filaments began in 1902 when Siemens developed a tantalum lamp filament that was more efficient than graphitized carbon filaments because it could operate at higher temperatures. Tantalum metal had a lower resistivity than carbon, which meant that the filament had to be quite long and required multiple internal supports to prevent sagging. The metal filament gradually shortened in use, and lamps used for several hundred hours became quite fragile, with filaments that could break and re-weld, though this usually decreased resistance and shortened the life of the bulb. General Electric bought the rights to use tantalum filaments and produced them in the US until 1913, when tungsten began to displace tantalum as the preferred material. Tungsten has the highest available melting point, but its brittleness was an obstacle until William D. Coolidge developed a method of making ductile tungsten from sintered tungsten while working for General Electric in 1906. By 1911, General Electric had begun selling incandescent light bulbs with ductile tungsten wire, which could be made into filaments while working for General Electric Company. The process required pressing tungsten powder into bars, then several steps of sintering, swaging, and wire drawing, and it was found that very pure tungsten formed filaments that sagged in use. A very small doping treatment with potassium, silicon, and aluminum oxides at the level of a few hundred parts per million, known as AKS tungsten, greatly improved the life and durability of the filaments. The predominant mechanism for failure in tungsten filaments is grain boundary sliding accommodated by diffusional creep, which causes the filament to sag nonuniformly and ultimately introduces further torque on the filament, leading to rupture. The coiled coil filament, invented by Burnie Lee Benbow in 1917 and later mass-produced by Hakunetsusha in 1936, allowed the filament to run hotter and more efficiently while lasting longer than a straight filament at the same temperature. The coiled coil filament evaporates more slowly than a straight filament of the same surface area and light-emitting power, which allows the filament to run hotter and more efficiently. The metal filament revolution was not just about improving the efficiency of the bulb, but about creating a more durable and reliable source of light that could be used in a wide range of applications, from home lighting to industrial processes. The metal filament also allowed for the development of halogen lamps, which use a halogen gas to reduce uneven evaporation of the filament and eliminate darkening of the envelope. The halogen cycle increases the lifetime of the bulb and prevents its darkening by redepositing tungsten from the inside of the bulb back onto the filament. The halogen lamp can operate its filament at a higher temperature than a standard gas filled lamp of similar power without loss of operating life, making it much smaller than normal incandescent bulbs and widely used where intense illumination is needed in a limited space. The metal filament revolution was a critical step in the evolution of the incandescent light bulb, paving the way for the more efficient and durable bulbs that would dominate the 20th century.

The Gas and the Getter

The introduction of inert gas fillings in incandescent light bulbs was a major breakthrough that allowed for greater temperatures and therefore greater efficacy with less reduction in filament life. Irving Langmuir found that filling a lamp with inert gas, such as nitrogen or argon, instead of a vacuum resulted in twice the luminous efficacy and reduced bulb blackening. He patented his device on the 18th of April 1916, and the gas fill became a standard feature in most modern bulbs. The gas reduces evaporation of the filament, but the fill must be chosen carefully to avoid introducing significant heat losses. For these properties, chemical inertness and high atomic or molecular weight is desirable. The presence of gas keeps the tungsten below its vapor pressure, allowing it to be operated at higher temperature without reducing its life. On the other hand, the presence of the gas leads to heat loss from the filament, and therefore efficiency loss due to reduced incandescence, by heat conduction and heat convection. The most commonly used fills are argon and nitrogen, where argon is used for its inertness, low thermal conductivity, and low cost, and nitrogen is added to increase the breakdown voltage and prevent arcing between parts of the filament. Krypton and xenon are also used in some lamps, where krypton is more advantageous than argon due to its higher atomic weight and lower thermal conductivity, but its use is hindered by much higher cost. Xenon gas improves efficiency because of its high molecular weight, but is also more expensive, so its use is limited to smaller lamps. The gas fill must be free of traces of water, which greatly accelerates bulb blackening. A very small amount of water vapor inside a light bulb can significantly increase lamp darkening, as water vapor dissociates into hydrogen and oxygen at the hot filament. The oxygen attacks the tungsten metal, and the resulting tungsten oxide particles travel to cooler parts of the lamp. Hydrogen from water vapor reduces the oxide, reforming water vapor and continuing this water cycle. Small amounts of substances such as zirconium are placed within the lamp as a getter to react with any oxygen that may bake out of the lamp components during operation. The getter was a crucial innovation that allowed for the production of economic bulbs lasting 800 hours, and the process was patented by an Italian inventor in 1896 and acquired by Edison in 1898. The gas fill also allowed for the development of halogen lamps, which use a halogen gas to reduce uneven evaporation of the filament and eliminate darkening of the envelope. The halogen cycle increases the lifetime of the bulb and prevents its darkening by redepositing tungsten from the inside of the bulb back onto the filament. The halogen lamp can operate its filament at a higher temperature than a standard gas filled lamp of similar power without loss of operating life, making it much smaller than normal incandescent bulbs and widely used where intense illumination is needed in a limited space. The gas fill was a critical innovation that allowed for the development of more efficient and durable bulbs, and it remains a standard feature in most modern incandescent light bulbs.

The Blackening and the Fix

Bulb blackening was a persistent problem that plagued early incandescent light bulbs, as the evaporated tungsten condensed on the inner surface of the glass envelope, darkening it. In a conventional lamp, the darkening is uniform across the entire surface of the envelope when a vacuum is used, but when a filling of inert gas is used, the evaporated tungsten is carried in the thermal convection currents of the gas and is deposited preferentially on the uppermost part of the envelope, blackening just that portion of the envelope. The study of the problem of bulb blackening led to the discovery of thermionic emission, the invention of the vacuum tube, and evaporation deposition used to make mirrors and other optical coatings. Preece coined the term the Edison effect on page 229, which refers to the phenomenon of electrons being emitted from a heated filament. A very small amount of water vapor inside a light bulb can significantly increase lamp darkening, as water vapor dissociates into hydrogen and oxygen at the hot filament. The oxygen attacks the tungsten metal, and the resulting tungsten oxide particles travel to cooler parts of the lamp. Hydrogen from water vapor reduces the oxide, reforming water vapor and continuing this water cycle. The equivalent of a drop of water distributed over 500,000 lamps will significantly increase darkening. Small amounts of substances such as zirconium are placed within the lamp as a getter to react with any oxygen that may bake out of the lamp components during operation. Some old, high-powered lamps used in theater, projection, searchlight, and lighthouse service with heavy, sturdy filaments contained loose tungsten powder within the envelope. From time to time, the operator would remove the bulb and shake it, allowing the tungsten powder to scrub off most of the tungsten that had condensed on the interior of the envelope, removing the blackening and brightening the lamp again. The halogen cycle was a major breakthrough that reduced uneven evaporation of the filament and eliminated darkening of the envelope by filling the lamp with a halogen gas at low pressure, along with an inert gas. The halogen cycle increases the lifetime of the bulb and prevents its darkening by redepositing tungsten from the inside of the bulb back onto the filament. The halogen lamp can operate its filament at a higher temperature than a standard gas filled lamp of similar power without loss of operating life, making it much smaller than normal incandescent bulbs and widely used where intense illumination is needed in a limited space. The blackening problem was a critical issue that had to be solved to make incandescent light bulbs practical for widespread use, and the development of getters and halogen cycles were key innovations that allowed for the production of more efficient and durable bulbs. The blackening problem also led to the development of new materials and processes, such as the use of zirconium as a getter and the development of halogen lamps, which remain important technologies in the lighting industry today.

The Efficiency Trap

Incandescent light bulbs are much less efficient than other types of electric lighting, with less than 5% of the energy they consume converted into visible light and the rest released as heat. The luminous efficacy of a typical incandescent bulb is 16 lumens per watt for a 120 volt bulb or 13 lumens per watt for a 230 volt bulb, compared with 60 lumens per watt for a compact fluorescent bulb or 100 lumens per watt for typical white LED lamps. The heat produced by filaments is used in some applications, such as heat lamps in incubators, lava lamps, Edison effect bulbs, and the Easy-Bake Oven toy. Quartz envelope halogen infrared heaters are used for industrial processes such as paint curing and space heating. The main difficulty with evacuating the lamps was moisture inside the bulb, which split when the lamp was lit, with resulting oxygen attacking the filament. In the 1880s, phosphoric anhydride was used in combination with expensive mercury vacuum pumps, but about 1893, an Italian inventor discovered that phosphorus vapours did the job of chemically binding the remaining amounts of water and oxygen. In 1896 he patented a process of introducing red phosphorus as the so-called getter inside the bulb which allowed the production of economic bulbs lasting 800 hours. The efficiency of the lamp increases with a larger filament diameter, and thin-filament, low-power bulbs benefit less from a fill gas, so are often only evacuated. The presence of gas keeps the tungsten below its vapor pressure, allowing it to be operated at higher temperature without reducing its life. On the other hand, the presence of the gas leads to heat loss from the filament, and therefore efficiency loss due to reduced incandescence, by heat conduction and heat convection. The gas fill must be chosen carefully to avoid introducing significant heat losses, and the most commonly used fills are argon and nitrogen, where argon is used for its inertness, low thermal conductivity, and low cost, and nitrogen is added to increase the breakdown voltage and prevent arcing between parts of the filament. Krypton and xenon are also used in some lamps, where krypton is more advantageous than argon due to its higher atomic weight and lower thermal conductivity, but its use is hindered by much higher cost. Xenon gas improves efficiency because of its high molecular weight, but is also more expensive, so its use is limited to smaller lamps. The efficiency of the lamp is also affected by the orientation of the filament, as gas flow parallel to the filament, such as a vertically oriented bulb with vertical or axial filament, reduces convective losses. The efficiency of the lamp increases with a larger filament diameter, and thin-filament, low-power bulbs benefit less from a fill gas, so are often only evacuated. The efficiency of the lamp is also affected by the presence of gas, which leads to heat loss from the filament, and therefore efficiency loss due to reduced incandescence, by heat conduction and heat convection. The efficiency of the lamp is also affected by the presence of gas, which leads to heat loss from the filament, and therefore efficiency loss due to reduced incandescence, by heat conduction and heat convection. The efficiency of the lamp is also affected by the presence of gas, which leads to heat loss from the filament, and therefore efficiency loss due to reduced incandescence, by heat conduction and heat convection.

The Ban and the Legacy

Since incandescent light bulbs use more energy than alternatives such as compact fluorescent lamps and LED lamps, many governments have introduced measures to ban them by setting minimum efficacy standards higher than can be achieved by incandescent lamps. Measures to ban light bulbs have been implemented in the European Union, the United States, Russia, Brazil, Argentina, Canada, and Australia, among others. The European Commission has calculated that the ban contributes to the economy and saves 40 terawatt-hours of electricity every year, translating in emission reductions. Objections to banning incandescent light bulbs include the higher initial cost of alternatives, lower quality of light of fluorescent lamps, and resistance to government regulation. Some people have concerns about the health effects of fluorescent lamps, and a 2008 opinion by the European Commission's Scientific Committee on Emerging and Newly Identified Health Risks found that some of the compact fluorescent lamps available at the time emitted higher levels of UV and blue light than incandescent lamps, which might aggravate the symptoms of people with conditions that make them light sensitive. A 2017 review in the World Journal of Biological Psychiatry reported that blue-rich white LED lighting can suppress melatonin and disrupt sleep and circadian rhythms, with potential implications for mental illness. The Phoebus cartel attempted to fix prices and sales quotas for bulb manufacturers outside of North America between 1924 and the outbreak of the Second World War, and in 1924 the Phoebus cartel agreed to limit life to 1,000 hours. When this was exposed in 1953, General Electric and other leading American manufacturers were banned from limiting the life. The Centennial Light is a light bulb that is accepted by the Guinness Book of World Records as having been burning almost continuously at a fire station in Livermore, California, since 1901, but it emits the equivalent light of a four watt bulb. A similar story can be told of a 40 watt bulb in Texas that has been illuminated since the 21st of September 1908. It once resided in an opera house where notable celebrities stopped to take in its glow, and was moved to an area museum in 1977. The incandescent light bulb has been a dominant technology for over a century, but its inefficiency has led to its gradual replacement by more efficient alternatives. The ban on incandescent light bulbs has been a contentious issue, with some arguing that the higher initial cost of alternatives and the lower quality of light of fluorescent lamps make them less desirable. The ban has also been criticized for its impact on the environment, as the production and disposal of incandescent light bulbs contribute to greenhouse gas emissions. The legacy of the incandescent light bulb is a testament to the ingenuity and perseverance of the inventors who developed the technology, and it remains an important part of the history of electricity and lighting. The ban on incandescent light bulbs has also led to the development of new technologies, such as halogen lamps and LED lamps, which are more efficient and durable than traditional incandescent bulbs. The legacy of the incandescent light bulb is a reminder of the importance of innovation and the need to balance efficiency with other factors, such as cost, quality, and environmental impact.

The Ribbon Machine

The manufacturing of incandescent light bulbs was revolutionized by the development of automated machinery, which allowed for the mass production of bulbs at a fraction of the cost of hand-blown bulbs. Until 1910, when Libbey's Westlake machine went into production, bulbs were generally produced by a team of three workers, two gatherers and a master gaffer, blowing the bulbs into wooden or cast-iron molds, coated with a paste. Around 150 bulbs per hour were produced by the hand-blowing process in the 1880s at Corning Glass Works. The Westlake machine, developed by Libbey Glass, was based on an adaptation of the Owens-Libbey bottle-blowing machine, and Corning Glass Works soon began developing competing automated bulb-blowing machines, the first of which to be used in production was the E-Machine. The Ribbon Machine, installed in 1926 in Corning's Wellsboro, Pennsylvania factory, surpassed any previous attempts to automate bulb production and was used to produce incandescent bulbs into the 21st century. The inventor, William Woods, along with his colleague at Corning Glass Works, David E. Gray, had created a machine that by 1939 was producing 1,000 bulbs per minute. The Ribbon Machine works by passing a continuous ribbon of glass along a conveyor belt, heated in a furnace, and then blown by precisely aligned air nozzles through holes in the conveyor belt into molds. Thus the glass bulbs or envelopes are created. A typical machine can produce 50,000 to 120,000 bulbs per hour, depending on the size of the bulb. By the 1970s, 15 ribbon machines installed in factories around the world produced the entire supply of incandescent bulbs. The filament and its supports are assembled on a glass stem, which is then fused to the bulb. The air is pumped out of the bulb, and the evacuation tube in the stem press is sealed by a flame. The bulb is then inserted into the lamp base, and the whole assembly tested. The 2016 closing of Osram-Sylvania's Wellsboro, Pennsylvania plant meant that one of the last remaining ribbon machines in the United States was shut down. The automation of bulb manufacturing was a critical step in the evolution of the incandescent light bulb, as it allowed for the production of bulbs at a fraction of the cost of hand-blown bulbs. The automation also allowed for the production of bulbs with more consistent quality and durability, which was essential for the widespread adoption of incandescent light bulbs. The automation of bulb manufacturing also led to the development of new technologies, such as the coiled coil filament and the halogen cycle, which were made possible by the precision and consistency of automated production. The legacy of the Ribbon Machine is a testament to the ingenuity and perseverance of the inventors who developed the technology, and it remains an important part of the history of electricity and lighting. The automation of bulb manufacturing has also led to the development of new technologies, such as LED lamps, which are more efficient and durable than traditional incandescent bulbs. The legacy of the incandescent light bulb is a reminder of the importance of innovation and the need to balance efficiency with other factors, such as cost, quality, and environmental impact.