|
08.08
Electric Lighting
By Frederik Nebeker, IEEE History Center
Since Edison's invention of a
practical incandescent bulb in 1879, electric
lighting has been part of popular culture. For
example, it was one of the great attractions of
the world's fairs in Chicago in 1894, in Buffalo
in 1901, and in St. Louis in 1904. Electric
lighting made cities inviting in the evening
hours; for example, it gave to Broadway the name
the Great White Way. And it made homes brighter
and more lively. Not surprisingly, in the early
decades of the century, pop culture references
to electric lighting were almost always
positive. Take, for example, Charlie Chaplin's
1931 movie "City Lights," which celebrated
electric lighting, both indoors and outdoors.
Despite its popularity, the
incandescent lamp was quite inefficient, so
engineers sought alternatives. Work in the 1920s
led to two new types of lamp that were
significantly more efficient — the high-pressure
mercury-vapor lamp and the low-pressure
sodium-vapor lamp. Both lamps were especially
suitable for street lighting, and both became
widely used in the 1930s. So-called discharge
lamps, their electric current flows from one
electrode through a gas or a metal vapor to
another electrode. The mercury-vapor lamp
produced a bluish light, whereas the
sodium-vapor lamp emitted a monochromatic,
orangish light. The latter was more efficient
and enjoyed widespread adoption in Germany and
the Netherlands. In other countries, including
the United States, England and France,
mercury-vapor lamps were preferred. The distaste
for the poor color rendering of the sodium lamp
was so great in the United States that some
states outlawed its use for street lighting. In
the recent movie, "Michael Clayton" (2007),
sodium lamps are assigned partial blame for a
traffic accident.
Neon lights, another type of
discharge lamp, also became common in the 1930s.
Movies have portrayed neon both positively and
negatively. For example, in "The Postman Always
Rings Twice" (1946) and "On the Town" (1949),
neon lights are seen as modern and attractive,
while in "It's a Wonderful Life" (1946) and
"From Here to Eternity" (1953), they are
associated with tawdry and decadent parts of
town.
Just before World War II, still
another type of discharge lighting — fluorescent
lighting — appeared. Researchers had long known
that discharge lamps often emitted ultraviolet
light. They knew also that certain minerals
converted ultraviolet light to visible light in
a process called fluorescence, the
re-emission of light at lower frequencies. Many
attempts to develop a practical lamp — placing
fluorescent materials in reflectors behind the
discharge tube, in a coating inside the tube, in
a coating outside the tube, or within the glass
itself — came to naught. Success finally came in
the late 1930s, with improved lamp design and
the discovery of fluorescent materials from
which one could obtain white light —
light having a distribution of frequencies
similar to sunlight. Fluorescent lighting was
featured at the 1939 New York world's fair.
Fluorescent lights appear in movies from the
1940s on, but are seldom remarked upon, though
they receive negative mention in "Goodbye,
Columbus" (1969) and "Clerks" (1994).
For the past 70 years,
incandescent and fluorescent lights have
dominated electrical lighting. The introduction
of the compact fluorescent bulb in the 1970s was
notable because it could be used in sockets
designed for incandescent bulbs. And at the end
of the century, an entirely new type of
electrical lighting became economically
important.
Light-emitting diodes (LEDs)
were invented in 1962, and soon found use as
indicator lights and for instrument and computer
displays. Great advances in LED technology in
the 1990s led to their widespread use in large
video screens and for lighting. Many movies,
such as "Hackers" (1995) and "Spider Man"
(2002), feature the huge video-screens in New
York City's Times Square. In the first years of
the 21st century, LEDs were beginning to be used
in traffic lights, automobile taillights and
flashlights. In turning electricity into light,
LEDs are significantly more efficient than
incandescent bulbs. As the manufacturing cost of
LEDs decreases, they will increasingly replace
incandescent lights.
Frederik Nebeker is Senior
Research Historian at the IEEE History Center at
Rutgers University in New Brunswick, N.J. Visit
the IEEE History Center's Web page at:
www.ieee.org/organizations/history_center.
Comments may be
submitted to
todaysengineer@ieee.org.
Opinions expressed are the
author's.
|
E-mail
this page to a friend
