Surprising
Science:
Who
is the Father of Television?
In
this picture of Baird's Televisior the housing for
the spinning disc can clearly be seen. The picture appeared
on the small screen at the right. (Courtesy
Early
Television Foundation)
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Ever hear of Vladimir K. Zworykin? How about John
Logie Baird? Or maybe you know the name of Paul Nipkow? If not,
how about Charles Francis Jenkins? No? Well surely you have
heard of Philo T. Farnsworth!
Who are these people? They all have a claim to
the title of "The Father of Television." Which one,
if any, is the rightful owner to that moniker, however?
The creation of television, one of the most important
inventions of the 20th century, has it roots firmly planted
in the 19th century. It was the logical outgrowth of the technology
of the telegraph and the photograph. As early as the 19th century,
inventors were filing patents on the devices that allowed for
transmission of moving images over wire.
Almost all technologies that display moving pictures
depend on a phenomena called persistance-of-vision. If the human
eye is presented with a series of still pictures very quickly,
faster than about 10 a second, it sees them not as individual
pictures but one continuous image. A motion picture camera uses
a long strip of film to take image after image of a scene, capturing
any movement within the series of pictures. As these are played
back through a projector, it gives the viewer the illusion of
a continuous moving scene.
Inventors wishing to transmit a moving picture
electrically would have to find a way to do something similar
by capturing image after image and sending them down a wire
to be reconstructed for viewing at another location.
Mechanical
Television
A German, Dr. Paul Nipkow, built the first, crude
machine to do this in 1884. Nipkow's camera device was based
on a spinning disc with 24 small holes punched in it. The holes
were arranged in a spiral so that as the disc was spun they
would one-by-one sweep out area where an image was focused onto
the disc with a lens. On the other side of the disc was a light-sensitive
photo cell that would generate an electrical signal when it
was struck by the light coming through the holes. In this way
the image was turned into an electrical signal. Every time the
disc rotated one full turn, another image would be sent down
the wire.
How
a mechanical TV works: The lens focuses the image on
a spinning disc. Holes sweep by the image allowing one
small point of light to pass through to a photocell
at a time. The photocell changes the varying light to
an electrical signal which is sent on a receiver which
reconstructs the image.(Copyright
Lee Krystek, 2002)
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Nipkow's receiver worked in reverse of his camera.
Instead of a photo cell there was a neon lamp. The neon lamp's
brilliance varied depending on the signal coming from the camera
and the light would pass through another spinning disc, synchronized
to the first, so that on the other side of the disc a fuzzy
image would form.
There were many problems with Nipkow's invention
and it never made it out of the laboratory: For one thing the
neon bulb did not generate enough light to make a very usable
picture. When a brighter bulb became available in 1917, other
inventors began to have an interest in Nipkow's work. In America
Charles Francis Jenkins started to build a system using a variation
of the spinning discs designed by Nipkow. In England an inventor
named John Logie Baird started experimenting with a similar
system.
Baird was 34 years old when he started building
his "Televisor" system. Working on a shoestring budget,
he built his first device using objects found in the attic where
he was experimenting. An old tea chest was used to support the
electric motor that turned the discs. The discs themselves were
cut out of cardboard. Other parts were mounted upon pieces of
scrap lumber. His lens came from an old bicycle lamp. Glue,
sealing wax and wire held the device together.
Amazingly, the jury-rigged system was able to produce
a tiny, flicking image. In 1926 Baird demonstrated a more refined
version of his mechanical television system to members of Britain's
Royal Institute. This lead to news coverage in the London
Times and money from financial backers so he could perfect
his device. By 1930 Baird was transmitting images over the BBC
transmitters at night after normal radio programs had ended.
This became the world's first regular television service.
Despite the success of Baird, this form of television,
which was referred to as mechanical television because of the
turning motors and discs involved, had many technical limitations.
Engineers working on mechanical televisions could not get more
that about 240 lines of resolution which meant the images would
always be somewhat fuzzy. The use of a spinning disc would also
limit the number of new pictures per second that could be seen
and this resulted in excessive flickering. It became apparent
that if the mechanical portion of television could be done away
with, higher quality and steadier images might be the result.
Electronic
Television
The first man to envision an electronic television
system was a British electrical engineer named A. Cambell Swinton.
In a speech he gave in 1911, Swinton described a design using
cathode-ray tubes to both capture the light and display an image.
A cathode-ray tube was a glass bottle with a long neck on one
end and a flattened screen on the other. The bottle was pumped
clear of air so that an "electron gun" in the neck
could shoot a stream of electrons toward the flattened end of
the tube which was covered with a coating of phosphor material.
When the electrons hit the material it would glow. By sweeping
the electron stream back and forth in rows from top to bottom
and varying the intensity of the stream, Swinton reasoned, an
image could be drawn in the same manner that Nipkow's disks
did.
A modified version of the tube could also be used
as a camera. If the flattened end could be given a sandwich
of metal, a non-conducting material and a photoelectric material,
light focused on the flattened end with a lens would produce
a positive charge on the inside of the surface. By sweeping
the electron stream across the flattened end, again in rows,
the charges could be read and the image could be turned into
a signal that could be sent to the display screen to be seen.
Swinton's idea almost exactly describes the way
modern electronic television works. While his forevision was
near perfect, Swinton, nor anyone else at the time, knew how
to actually engineer such a system and make it work. An electronic
system, if it could be made to work, however, would operate
at much faster speeds than any mechanical system could and would
allow the picture to be composed of more rows, therefore increasing
the quality of the image.
Philo
T. Farnsworth.
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It was eleven years after Swinton's lecture that
a teenager from Utah became interested in electronic television.
Philo T. Farnsworth had read about Nipkow's disc system and
decided it would never produce a high quality picture. After
experimenting with electricity, he declared to one of his high
school teachers that he thought he could devise a better system.
He proceeded to lay it out for the surprised man on the classroom
blackboard. The teacher encouraged Farnsworth and Farnsworth
set out to California to build a laboratory where he could experiment
with his ideas. Working in darkened rooms in Los Angeles and
later San Francisco, Farnsworth kept his work so secret that
his laboratory was once the subject of a raid by police, who
thought that he was using a still to produce illegal alcoholic
beverages.
By September of 1927 Farnsworth was transmitting
a sixty line picture from camera to screen using an entirely
electronic system. It was at this point in time his work drew
the attention of David Sarnoff. Sarnoff was chief of the Radio
Corporation of America (RCA): the leader in supplying radios
and radio parts to the United States.
Many of RCA's radio patents would soon expire, so
Sarnoff was searching for another market he could corner and
television was the obvious choice. After hiring Vladimir Zworykin,
a Russian immigrant who had been experimenting with mechanical
television for a decade, Sarnoff sent him to California to look
at Farnsworth's work. Later Sarnoff would visit Farnsworth's
laboratory himself.
Sarnoff and Zworykin quickly realized the value
of Farnsworth's invention and Sarnoff tried to buy the young
man out for $100,000. Farnsworth, thinking he could make more
in collecting patent royalties from RCA than selling his invention
to them, refused. Sarnoff, miffed, said, "Then there's
nothing here we'll need" and sent Zworykin off to build
their own version of the technology.
Farnsworth's designs kept showing up in Zworykin's
work and lawsuits between the two companies followed. Eventually
RCA was forced to pay Farnsworth $1,000,000 in licensing fees,
but the onset of WW II delayed the introduction of television
to most of the United States and the market for electronic television
did not really take off until after the war. By then many of
Farnsworth's key patents had expired and he never made the money
he probably really deserved for his contributions to electronic
television.
Adding insult to injury, most of the history of
television was written by RCA employees and they, perhaps in
revenge for the license they were forced to take out, left Farnsworth's
contributions completely out of the story.
Demise
of Mechanical Television
So what happened to the mechanical television being
broadcast in Britain? Baird soon realized he needed to get the
help of the BBC to make his mechanical system a complete success.
By the 1930's, however, the BBC realized that the future was
with electronic TV, not mechanical. Starting in November of
1936, Baird's mechanical system was broadcast on alternating
weeks with an electronic system from EMI. The British public
was invited to choose which one they liked best. The electronic
system was clearly superior and Baird was taken off the air.
Though Baird would try to sell his system to movie houses, those
plans ground to a halt when WW II started and the BBC's TV service
was shut down until hostilities were over.
In 1939 RCA and Zworykin decided to demonstrate
their new electronic TV system at the World's Fair in New York
City. Not much more development was done until after the WW
II was over, but by 1946 people could buy a ten-inch table model
for $375.
So who was the true Father of Television? This ubiquitous
invention, like many others, had many people contributing to
its creation. It's obvious, however, that much of the credit
for making electronic television should probably go to Philo
Farnsworth. Court after court hearing Farnsworth v. Zworykin
acknowledge that his ideas found their way into the first commercial
systems built by RCA. Many of the processes that operate inside
a TV today were developed in his darkened, secret lab in California.
A
Partial Bibliography
They
All Laughed by Ira Flatow, HarperCollins Publishers, 1992.
Inventing
Modern America by
David E. Brown,
The MIT Press, 2002.
The
Scientific Breakthrough by Ronald W. Clark, G.P. Putnam's
Sons, 1974.
Copyright Lee Krystek 2002. All
Rights Reserved.