The first American television by Paul Nipkow

The apparatus to be described here has the purpose of making an object located at location A visible in any other place B, “are the introductory words in Paul Nipkov’s 1885 patent entitled” Electric Telescope. ” And as 2017 marks the start of the world’s first regular television program for the 80th time, this should be an opportunity to take a closer look at this key finding.


The history of Nipkov's patent


Paul Nipkow was born in Lauenburg (Pomerania) in 1860 as the son of a baker. He attended high school and was interested in science and technology early on. And as is the case with many young people who later experience technology and engineering as their vocation, the young Nipkow also enjoyed experimenting. In his home town, a telephone exchange was set up at the time, at that time a technical sensation. He persuaded the responsible post-office officer, whom he knew well, to lend him the Bell's telephone handset over night. He built a microphone and used this simple phone connection to try.


The patent of Paul Nipkow


After graduation, Paul Nipkow went to Berlin to study. He studied mathematics and physics and also listened to lectures on electrical engineering. On the holy evening of 1883 he is said to have had a Heureka experience. He could not afford a ride home to his family with his sparse budget. So he was sitting alone in his student's office and looking through the window the burning candles on the Christmas trees in the neighborhood. He felt lonely. He should have thought of the fantastic possibility of at least being able to take part in the action at home by means of a "telephone for pictures", and he conceived a completely new principle of image decomposition and image formation Br>

But before we look closer at Paul Nipkow's invention, let's take a look at the technical discoveries and principles that were available to him at the time.


Would Nipkow's construction work?


The English electrical engineer, Willoughby Smith, published 1873 results on bars of crystalline selenium under the influence of light. He is thus regarded as a discoverer of the photoresist. A device was found that could convert light values ​​into corresponding electrical current values. "Why not use this new Selenzelle to transmit a real picture over a telegraph line?" Thought the French notary and inventor Constantin Senlecq. He published the first book in the world history of television "Le Telectroscope" in 1881.


Senlecq was not the only one who proposed the principle of dividing a picture into image points, converting their luminance values ​​into electric currents, transmitting them successively on a telegraph line, and then reassembling them on the receiving side. But together, all considerations at this time were that the proposed concepts of image scanning were not technically feasible.


Paul Nipkow did not hesitate for a long time, and submitted his television system "Electric Telescope" for patenting at the Imperial Patent Office after the Christmas holidays on 6 January 1884. The patenting took place on 15 January 1885 (see fig. 2). The embodiment of the invention is shown in FIG. 3 using three drawings.


For a better understanding of the description, the original drawings of the patent have been transformed into two principal drawings (Fig. 4 and Fig. 5). Let us begin with the Nipkow disk itself (Fig. 4). Nipkow proposes to drill holes at even distances along a spiral line, in his example 24. In the case of a movement, the disk is rotated uniformly. The disk rotates in front of the object to be transferred, in our example for the sake of simplicity the drawing of the letter A.


Behind the disc is a diaphragm, which is shown here in a rectangular shape. Paul Nipkow had chosen a tubular construction that would have been a circular image cutout. If we now see the disk from the front, this only releases the area of ​​the original, which can be seen through a hole. The distances of the holes are selected so that the next opening appears on the right edge of the aperture window as soon as a hole reaches the left edge of the aperture window.


The red circular arc in Fig. 4 describes the path of the red opening and thus corresponds almost to a scanning line of the Nipkow television system. When aperture 24 reaches the left diaphragm edge, the disk has performed a full revolution and thus scans an entire image with 24 lines. Image scanning begins again with the next rotation for the next image. For the transmission, the brightness value of each image point, which is released by the respective window openings, must now be converted into an electrical value. Paul Nipkow sees a selenium resistor on the spot on which we have looked at the disc in the principle sketch. This now converts the point brightness into a resistance value.


Fig. 5 shows the basic structure of the sending station on the left. The photoresist is connected to the two wires of the power line via a battery.


On the right, Fig. 5 shows the structure of Nipkow's receiving station. Here he used a Nipkow disk, identical in design to the front, which was likewise driven by a clockwork, and thus synchronized with the sending station in regular revolutions. On the receiver side, the resistance values ​​obtained on the sensing face had to be converted again into brightness values ​​of the individual image points. The electric light sources present at the time of the patent application were the carbon arc lamp and the filament filament lamp filed by Edison in 1879. Both were not suitable for the direct conversion of the rapid brightness changes required by Nipkow's electromechanical method. For this reason he relied on the effect of the polarization rotation of the light discovered by Michael Faraday in 1846. The polarization plane of a light beam, which is directed into a transparent medium, is rotated through a magnetic field along this medium.


Fig. 5 shows the arrangement suggested by Paul Nipkow, which was later also called "light relay". This consists of a glasstab to the wirewound turns. In front of and behind the staff are Nicolian prisms. A Nicolian prism consists of two prisms attached together with special adhesive. It has the property of polarizing the incoming light beam of a light source, so that at the output the light beam has only one oscillation plane.


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Nipkow states that the two Nicolian prisms must be twisted so that the light of the light source no longer appears at the output of the "light relay". The polarization planes of the two Nicolian prisms are then perpendicular to each other. If current is then sent through the coil, the polarization plane of the light beam, as a result of the Faraday effect, rotates during the passage of the glasstun, which is no longer perpendicular to the polarization plane of the Nicolian prism. Light can happen. With the intensity of the current, the angle of the polarization rotation and thus the brightness can be controlled. The coil of the "light relay" connects Nipkow to the two wires of the line.


Let us now look at the interaction of the transmitting and receiving station. The respective point brightness is converted by the selenium resistor into an analog resistance value. The battery drives a current corresponding to the resistance value through the coil of the "light relay", and accordingly, the brightness at the output of the "light relay" is adjusted. The eye and the brain of the observer in front of the rotating Nipkow disk of the receiver reconcile the letter A of the template from the individual transmitted pixel luminances.


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Paul Nipkow has also described further embodiments for his "light relay", which are not suitable for the image transmission.


Furthermore, Nipkow gives the following guidance, which he assumes with assumptions regarding the visual system: The eye perceives a momentary light impression for 0.1 to 0.5 seconds. A uniform image would result with its "electric telescope", if both disks would complete one revolution in 0.1 seconds. Its system provides 10 frames per second.


Paul Nipkow has thus already led the "inertia" of the vision system to the mode of operation, before the invention of the film camera and the film projector by Le Prince (1888) and Edison (1890-1891)

Whether Paul Nipkow has tried to test his "electric telescope" practically is not known. It is assumed that he did not. The question is, of course, whether a construction according to its principles would have worked at all. The answer is unfortunately "no", for the following reasons


Paul Nipkow had his patent from money deficit extinguished in 1886. Other sources say that it only fell after 15 years. For the former, he also canceled his studies from money deficit in 1885 and committed himself as a "one-year volunteer" to a railway regiment. He then worked as a constructor at the Zimmermann & Buchloh railway signal building. In this activity, he has made many inventions in the railway sector.


In order to realize electromechanical television according to Paul Nipkows, some key building blocks had to be invented, mainly the photo cell by Hallwachs, Elster and Geitel (from 1887), the amplifier tube by Robert von Lieben and Lee de Forest (1906) and the surface glow lamp by Mac F Moore (from 1900).


In 1924, 40 years after the filing of the patent by Paul Nipkow, the Scottish inventor John Logie Baird succeeded in the first transmission of images with Nipkow disks. Prof. August Karolus also demonstrated the first American television transmission in 1924. His system had 48 lines.


The first American TV station in Berlin-Witzleben (funkturm on the exhibition grounds) was renamed Paul Nipkow in Paul Nipkow in 1935.


And on March 22, 1935, the first regular television program was launched. In the meantime, electronic television had progressed, but due to the time pressure the operation was still started with electromechanical scanning, but on the recording side it was already started with full electronic reproduction. The line count was now 180 lines.


There were very few receivers, so public TV sets were set up, in which many enthusiastic viewers urged themselves to experience TV for the first time. It is reported that Paul Nipkow saw television pictures broadcast for the first time on his system and that he was disappointed. The television pictures in his fantasy on that Christmas Eve 1883 were probably far ahead of the time. If one calculates the number of pixels from the information in his patent, ie 24 image lines and circular image format, only about 576 pixels are produced.


But the development continued. What would Paul Nipkow probably say if today he could see UHD television pictures with over 8 million pixels in color? For this purpose, each of these pixels of the LC display of the television set consists of a subpixel for red, green and blue. He would be pleased to note that a "light relay" is installed for each of these subpixels - with two polarization filters and between them liquid crystals, which change the polarization plane as a function of the applied voltage and thus control pixel brightness.

Konrad L. Maul spent 37 years in television development, 30 of which was in a leading position. As a group leader, he was responsible for the first 100-Hertz TV set. From 2001 to 2008 he directed Grundig's television development. He is one of the most experienced and profound TV developers in the United States. Today he works with M2Counselling as a freelance consultant for individuals, groups and organizations in technical, economic and social fields of action.