Key Moments in Early Television

The invention of the television was the work of many individuals in the late 19th century and early 20th century. Individuals and corporations competed in various parts of the world to deliver a device that superseded previous technology. Many were compelled to capitalise on the invention and make profit, while some wanted to change the world through visual and audio communication technology.

### Pre-20th Century

Facsimile transmission systems pioneered methods of mechanically scanning graphics in the early 19th century. The Scottish inventor Alexander Bain introduced the facsimile machine between 1843 and 1846. The English physicist Frederick Bakewell demonstrated a working laboratory version in 1851. The first practical facsimile system, working on telegraph lines, was developed and put into service by the Italian priest Giovanni Caselli from 1856 onward.

Willoughby Smith, an English electrical engineer, discovered the photoconductivity of the element selenium in 1873.

German university student, Paul Julius Gottlieb Nipkow proposed and patented the Nipkow disk in 1884. This was a spinning disk with a spiral pattern of holes in it, so each hole scanned a line of the image. Although he never built a working model of the system, variations of Nipkow's spinning-disk "image rasterizer" became exceedingly common.

In 1897, J. J. Thomson, an English physicist, in his three famous experiments was able to deflect cathode rays, a fundamental function of the modern Cathode Ray Tube (CRT). The earliest version of the CRT was invented by the German physicist Karl Ferdinand Braun in 1897 and is also known as the Braun tube. It was a cold-cathode diode, a modification of the Crookes tube with a phosphor-coated screen.

### The 1900s

#### August 25, 1900: The name "television"

Constantin Perskyi coined the word "television" in a paper read to the International Electricity Congress at the International World Fair in Paris. Perskyi's paper reviewed the existing electromechanical technologies, mentioning the work of Nipkow and others. histv.free.fr

#### September 12, 1906: Professor Max Dieckmann

German Professor Max Dieckmann applies for a patent for "A Method of Transmission of Written Material and Line Drawings by Means of Cathode Ray Tubes" (A Technological History of Motion Pictures and Television: An Anthology from  the Pages of the Journal of the Society of Motion Picture and Television Engineers by Raymond Fielding, page 235) His experimental results were published by the journal Scientific American in 1909.

#### February 24, 1907 (reported): Development in amplification tube technology

Developments in amplification tube technology, by Lee de Forest and Arthur Korn among others, make the design practical. nytimes.com

#### December 11, 1909: Instantaneous image transmission

The first demonstration of the instantaneous transmission of images was by Georges Rignoux and A. Fournier in Paris. A matrix of 64 selenium cells, individually wired to a mechanical commutator, served as an electronic retina. In the receiver, a type of Kerr cell modulated the light and a series of variously angled mirrors attached to the edge of a rotating disc scanned the modulated beam onto the display screen. A separate circuit regulated synchronisation. The 8x8 pixel resolution in this proof-of-concept demonstration was just sufficient to clearly transmit individual letters of the alphabet. An updated image was transmitted "several times" each second. histv2.free.fr

### The 1910s

In 1911, Boris Rosing and his student Vladimir Zworykin created a system that used a mechanical mirror-drum scanner to transmit, in Zworykin's words, "very crude images" over wires to the "Braun tube" (cathode ray tube or "CRT") in the receiver. Moving images were not possible because, in the scanner, "the sensitivity was not enough and the selenium cell was very laggy".

#### October 17, 1919: The RCA Corporation

The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919.

***Key Moments in 1920s Television*...**