Television, Beginning Ideas (late Nineteenth and Early Twentieth Century)

In 1873 Willoughby Smith discovered the photoconductive property of selenium, the changing of electrical conductance with light falling on its surface. This property was utilized in many of the early schemes for television (the word dates from 1900) until the development of suitable amplifiers and photoemissive cells made selenium cells obsolete in the 1920s.

The photoconductive property of selenium was easily demonstrated and, in the following decade there was an expectation that ‘‘distant vision’’ would soon be a reality. This expectation was probably encouraged by the work in 1880 of Alexander Graham Bell and Charles Tainter on the photophone, a communication device that permitted sounds to be transmitted over a distance by means of a modulated beam of sunlight aimed at a selenium cell.

The simplicity of the photophone and the lack of effort involved in its development, together with Bell’s invention of the telephone in 1876, which enabled ‘‘hearing by electricity’’ to be readily implemented, stimulated workers in their quest to achieve ‘‘seeing by electricity.’’ Several suggestions for ‘‘telectro- scopes’’ were put forward in the 10-year period following Willoughby Smith’s 1873 discovery.

The earliest ideas for these were based on notions that had been advanced from 1843 for picture telegraphy systems, but from around 1883 more appropriate ideas began to be proposed. In a basic system of television the light values of each elementary unit area of an illuminated scene or object are determined by an analyzing scanner- photoelectric cell arrangement and the amplified varying electrical signal is transmitted to the receiving apparatus. Here, the signal is again amplified and applied to an electrically controlled varying light source system so that, by means of a synthesizing scanner, an image of the original scene or object can be reproduced.

The implementation of such a system was not easy and more than 50 years would elapse, before John Logie Baird demonstrated a rudimentary form of television. Nevertheless, the work of the nineteenth century television pioneers was not wholly unproductive and, by the end of the century, some of the basic system components needed to implement a television scheme had been put forward.

The ideas of Paul Nipkow (1883), Lazare Weiller (1889), and Marcel Brillouin (1894) led to television scanners—the apertured disk, the mirror drum, and the lens disk, respectively— which were widely utilized in the 1920s and 1930s. In addition Wilhelm Hallwachs’ work on the photoelectric effect in 1888 followed by the detailed investigations from 1889 of Julius Elster and Hans Geitel on photoelectricity, together with the fundamental researches which were being undertaken, contemporaneously, on the conduction of electricity in gases and in vacuums were important contributions that were to play a vital part in the progress of television. The latter work led to the invention, by Karl Ferdinand Braun in 1897, of the cathode ray tube (CRT) as a practical laboratory instrument.

Following Braun’s publication, the development and use of cathode ray tubes was pursued by several investigators, and so it was perhaps inevitable that it would be incorporated into a television system. Boris Rosing, in Russia in 1908, was the first person to engage in work on television using a CRT receiver, although prior to this date Max Dieckmann and Gustav Glage, in 1906, had developed a ‘‘method for the transmission of written material and line drawings by means of cathode ray tubes,’’ In his work, Rosing was assisted by his student Vladimir Zworykin who later, from 1923, and in the U.S., tried to evolve an all-electronic television system. He described his ‘‘kinescope’’ (CRT) display tube in 1929 and his ‘‘iconoscope’’ (CRT) camera tube in 1933.

On 9th May 1911 Rosing recorded in his notebook, ‘‘... A distinct image was seen [on the screen of the CRT] for the first time consisting of four luminous bands.’’ In the same year Alan Archibald Campbell-Swinton elaborated on his earlier (1908) ideas, founded on a cathode ray camera tube and a cathode ray display tube, for an all-electronic television system. These ideas influenced James McGee who, from 1932, led the team at Electric and Musical Industries (EMI), which developed the emitron camera tube, the British equivalent of the iconoscope.

During the period 1912-1922 only a few new schemes for television were advanced. This situation changed greatly from 1923 because of technical advances in electronics. In 1904 J. Ambrose Fleming invented the diode valve. Two years later Lee de Forest invented the Audion (triode) valve and in 1912 discovered that the valve, in addition to having applications in detecting and amplifying circuits, could be utilized in an oscillator to generate electromagnetic waves.

World War I gave an impetus to the use of valves in signaling systems, and so stimulated developments in circuit and radio techniques, so that by 1918 triodes could be manufactured to cover wide power and frequency ranges and were suitable for both receiving and transmitting purposes. Consequently, by 1920 the time was oppor tune for the establishment of sound broadcasting: the radio systems were available and public demand was growing.

The growth of commercial radio telephony, domestic broadcasting, and facsimile transmission influenced the progress of television. By the early 1920s, all the basic components of a rudimentary television system appeared to be at hand; and so, from around 1923 determined efforts to advance television were being made in the U.K., the U.S., France, Germany and elsewhere. At first these endeavors were mainly those of individuals—Baird in the U.K., Charles Jenkins in the U.S., Edwin Belin of France and Denes von Mihaly, a Hungarian working in Germany—working in isolation from others, but from 1925 this situation changed.

Bell Telephone Laboratories in New York began an ambitious program that led to an impressive demonstration of the first U.S. television in April 1927, by wire from Washington D.C. to New York. Later, General Electric, Westinghouse Electric and Manufacturing Company, and the Radio Corporation of America (RCA), of the U.S.; Fernseh AG and Telefunken of Germany; the Marconi Wireless Telegraph Company, the Gramophone Company, Electric and Musical Industries (EMI), in addition to Baird’s company in the U.K. and its subsidiaries, and others, all carried out experimental investigations in the television field.

Baird made transatlantic transmissions of television signals by shortwave radio from London to New York in February 1928, and began experimental broadcasts in collaboration with the British Broadcasting Corporation (BBC) in September 1929.

In the U.K., the determined efforts of EMI led, on November 2, 1936, to the inauguration of the world’s first, public, regular high-definition television service from studios and transmitters at Alexandra Palace, north London.