Nipkow

Nipkow, Paul Gottlieb

ACHIEVEMENT(S): TV scanning system

NICKNAME/ALIAS: None

DATE/PLACE OF BIRTH: 22 August 1860, at Lauenburg, Pommern, Pomerania [now

Lebork, Poland]

DATE/PLACE/AGE AT DEATH: 24 August 1940, in Berlin, Germany. Aged 80

DISCIPLINE: Electrical engineer

FIELD: Television

LANGUAGE: German

PARENTS: Friedrich Wilhelm Nipkow (d. 1883) and Theresia Auguste Catharina

Magdalinski (1839-1919)

SIBLINGS: Unknown

SPOUSE: Sofie Colonius

CHILDREN: Unknown

EDUCATION: Neustadt Gymnasium, 1872-78; University of Berlin, 1882-85

MAJOR WORK: 'Der Telephotograph u.d. elektr. Teleskop' (in 'Elektrotech.'

Zs. 6), 1885

LIFE AND TIMES: In 1882 Nipkow enrolled as a physics student at the

University of Berlin under Helmholtz*, and after

receiving his degree he began studying for a doctorate in electrical

engineering. In 1884, while still a student, Nipkow developed and patented the

first working TV* system, using electricity (in the form of a

selenium cell) to transmit images on to a distant screen.

The light-sensitive properties of selenium were discovered in 1873 by a

British telegraph operator named Louis May, who found that when it was

exposed to light, selenium was a strong conductor of electricity, and that

the light values could be converted into equivalent electrical values (and

back again). A few years later, in Boston, U.S., an American, G.R.

Carey found a way of picking up the image at the back of a camera by

using dozens of tiny light-sensitive selenium cells (later known as

photoelectric cells) arranged in a mosaic and connected to a battery.

As each cell responded to the intensity of light (from the picture or scene), a

greater or lesser current of electricity would flow down wires that

connected each cell to a lamp on a corresponding spot on a "receiver", or

screen. (Electromagnets would be connected to each of the lamps on the

receiver plate in order to regulate the amount of light on each section).

But in Carey's system, for a recognizable picture to be transmitted and

received, hundreds of cells, lamps and wires were needed. Even to match only the

poor quality of a newspaper photograph, 15,000 individual connections were

required for a two-inch square picture.

As a result of Carey's work, early researchers began to theorize that the

ideal television system would consist of one light cell connected by a

single pair of wires to one lamp; a cell in a camera would then record the

brightness of each part of the picture in turn, and the lamp at the other

end should be able to reproduce each point at the correct intensity. It was

the practical solution to this problem that Nipkow was working on in 1883-84

when he developed a remarkably simple mechanism - his mechanical television

pick-up device, which used a scanning method to cut an object into a

series of arcs, the sequences of light and dark areas in which were detected

by a photoelectric cell.

Central to his mechanism was the Nipkow disc, which contained a spiral of 24 holes and rotated at 600 rpm between the object to be transmitted and a photoelectric cell. As the disc rotated, Nipkow theorized, only one point of the object would be exposed to the cell at a time, having the effect of dividing the object into lines, but with the whole object

covered by each revolution of the disc. The light would pass through the

individual holes and enter the photoelectric cell, which would then convert

the sequence of light into an electrical signal. In turn, this signal (the

information about the image - made up of light and darkness) would then be

transmitted over a single circuit to a lamp which, controlled by the cell,

would vary rapidly in brightness. The light would then fall on to a

second Nipkow disc, rotating at precisely the same speed and in

synchronization with the first disc. Its holes would allow light

from the lamp to project the disassembled image section by section on to the

receiver's screen. So, as the disc rotated, the total numbers of sections

would be blurred together by the human eye, and an image of the original

object would be reproduced on the screen.

Although it worked well in theory, Nipkow couldn’t amplify the electric current created by the selenium enough to drive a receiver. It was not until 1906 and the development of the amplification tube (or triode) by De Forest* that the serious development of mechanical television could begin, resulting in the first television transmission of a human being’s image by the Scottish inventor John Logie Baird* in London in 1926, using Nipkow discs in both camera and receiver.

For most of his working life after getting his doctorate in 1885, Nipkow was employed as an engineer by a German company that manufactured railway-signalling equipment. However, he finally gained recognition for his pioneering invention in 1934, when he was made Honorary President of the newly-formed German Television Society. The Nipkow disc was, however, made obsolete the same year by electronic scanning devices developed by Zworykin* in the United States and Marconi-EMI in Europe.

ASSESSMENT: None

EXTRA CONNECTIONS: None

ONELINER: Paul Nipkow, inventor of first TV scanning process

BIBLIOGRAPHY: EB, Routledge Biographical Dictionary of Technology, German

Biographical Dictionary