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The invention of the light bulb is sometimes
attributed to Thomas Alva Edison, but today it is well-known that
Heinrich Goebel built functional bulbs three decades earlier. Many
others also contributed to the development of a practical device
for the production of electrically generated lighting.
In 1801 Sir Humphry Davy, an English chemist, made platinum strips
glow by passing an electric current through them, but the strips
evaporated too quickly to make a useful lamp. In 1809 he created
the first arc lamp, which he demonstrated to the Royal Institution
of Great Britain in 1810, by creating a small but blinding arc
between two charcoal rods connected to a battery.
In 1820 a British scientist Warren De la Rue enclosed a platinum
coil in an evacuated tube and passed an electric current through
it. The design was based on the concept that the high melting
point of platinum would allow it to operate at high temperatures
and that the evacuated chamber would contain less gas particles to
react with the platinum, improving its longevity. Although it was
an efficient design, the cost of the platinum made it impractical
for commercial use.
In 1835 James Bowman Lindsay demonstrated a constant electric
light at a public meeting in Dundee. He stated that he could "read
a book at a distance of one and a half foot". However having
perfected the device, to his own satisfaction, he turned to the
problem of wireless telegraphy and did not develop the electric
light any further.
In 1841 Frederick de Moleyns of England was granted the first
patent for an incandescent lamp, with a design using powdered
charcoal heated between two platinum wires.
In 1854, the German inventor Heinrich Goebel developed the first
'modern' light bulb: a carbonized bamboo filament, in a vacuum
bottle to prevent oxidation. In the following five years he
developed what many call the first practical light bulb. His lamps
lasted for up to 400 hours. He did not immediately apply for a
patent, but his priority was established in 1893.
Joseph Wilson Swan(1828-1914) was a physicist and chemist born in
Sunderland, England. In 1850 he began working with carbonized
paper filaments in an evacuated glass bulb. By 1860 he was able to
demonstrate a working device but lack of a good vacuum and an
adequate supply of electricity resulted in a short lifetime for
the bulb and inefficient light. By the mid-1870s better pumps
became available, and Swan returned to his experiments. Swan
received a British patent for his device in 1878. Swan reported
success to the Newcastle Chemical Society and at a lecture in
Newcastle in February 1879 he demonstrated a working lamp that
utilized a carbon fibre filament. The most significant feature of
Swan's lamp was that there was little residual oxygen in the
vacuum tube to ignite the filament, thus allowing the filament to
glow almost white-hot without catching fire. From this year he
began installing light bulbs in homes and landmarks in England and
by the early 1880s had started his own company.
Across the Atlantic, parallel developments were also taking place.
On July 24, 1874 a Canadian patent was filed for the Woodward and
Evan's Light by a Toronto medical electrician named Henry Woodward
and a colleague Mathew Evans, who was described in the patent as a
"Gentleman" but in reality a hotel keeper. They built their lamp
with a shaped rod of carbon held between electrodes in an glass
bulb filled with nitrogen. Woodward and Evans found it impossible
to raise financial support for the development of their invention
and in 1875 Woodward sold a share of their Canadian patent to
Thomas Edison.
Edison purchased the Woodward and Evans patent and had a team of
developers search for an alternative filament material. Eventually
he used a carbon filament that burned for forty hours (first
successful test was on October 21, 1879; it lasted 13 1/2 hours).
Edison continued to improve their design. By 1880 he had a device
that could last for over 1200 hours using a bamboo-derived
filament, longer than the 400 hours of Heinrich Goebel's earlier
light bulb.
In January 1882, Lewis Latimer received a patent for the "Process
of Manufacturing Carbons," an improved method for the production
of light-bulb filaments which yielded longer lasting bulbs than
Edison's technique.
In Britain, Swan took Edison to court for patent infringement.
Edison lost and as part of the settlement, Edison was forced to
take Swan in as a partner in his British electric works. The
company was called the Edison and Swan United Electric Company.
Eventually, Edison acquired all of Swan's interest in the company.
Swan sold his U.S. patent rights to the Brush Electric Company in
June 1882.
Edison and his team did not find a commercially workable filament
(bamboo) until more than 6 months after Edison filed the patent
application. The weak and short lived (40-150 hours) carbon
filament was eventually superseded by the tungsten filament. In
1903 Willis Whitnew invented a filament that would not make the
inside of a lightbulb turn dark. It was a metal-coated carbon
filament. In 1906, the General Electric Company were the first to
patent a method of making tungsten filaments for use in
incandescent lightbulbs. The filaments were costly, but by 1910
William David Coolidge (1873-1975) had invented an improved method
of making tungsten filaments. The tungsten filament outlasted all
other types of filaments and Coolidge made the costs practical.
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