Presentation on the history of the creation of television for children. Presentation. History of television. How TVs work

The beginning of the development of phototelegraphy is associated with the projects of A. Bain (1842), F. Bakewell (1847) and G. Caselli (1862). The difference between phototelegraphy and television is approximately the same as between photography and cinema. The first successes in transmitting still images over communication lines attracted the attention of scientists and inventors to the problem of television. But for the transition from phototelegraphy to television, that is, to the direct transmission of moving images, new methods and technical means were required, and enormous technical difficulties had to be overcome.

Next stage: Kern system An attempt to build a television system by analogy with the structure of the human visual apparatus. The centers of the cerebral cortex where visual perceptions are created were represented by light sources (for example, incandescent light bulbs) located on a second panel at the reception site. The conversion of optical images into electrical signals in the Kern system had to be carried out simultaneously and continuously by all photoresistors. All changes in the transmitted image would be reflected in changes in the brightness of the light sources in the receiving device, which in principle made it possible to transmit moving images.

System by M. Sanlek, A. di Paiva and P. I. Bakhmetyev A transition was made from a multi-channel image transmission system to a single-channel one. Unlike the purely electrical static system of Kern, which did not contain any mechanical moving parts, the systems of Sanlek, de Paiva and Bakhmetyev required the use of more or less complex mechanisms for scanning or decomposing the image into elements.

It was an opaque circle of large diameter, at the outer edge of which small round holes were located in a spiral at the same angular distance from one another. Each subsequent hole is shifted by the amount of its diameter towards the center of the disk. In the transmitter, the disk was located between the transmitted object and the selenium photoresistor. The image of the transmitted object was focused by the lens onto the plane of the disk. When the disk rotated through its holes, light passed onto the photoresistance alternately from individual image elements. Each hole produced one line of image. During one revolution of the disk, the photoresistance was sequentially affected by light from all image elements, which corresponded to the transmission of one frame.

B. L. ROZING - creator of television Achievements and dates: used an electron beam to reproduce images in an electric telescope system. In 1902, B. L. Rosing used a cathode ray tube in the receiving device of a system with electrochemical elements on the transmitting side. On July 25, 1907, he applied for a privilege to invent the Method of Electrical Transmission of Images. He received a gold medal and an award named after an honorary member of the society, K. F. Siemens.

In 1924, B. L. Rosing recreated his system and made a number of improvements to the transmitting and receiving devices. A new optical system has been developed to produce undistorted images in terms of brightness, clarity and magnification. Experiments carried out by S. L. Rosing at LEEL in the years showed the full functionality of his television system and the correctness of the principles on which it was built. In laboratory conditions, simple images could be transmitted with 48 lines of clarity. Rosing acts as a staunch supporter and promoter of electronic television

A real breakthrough in electronic television technology was made by B. Rosing’s student V. K. Zvorykin. in 1923 he applied for a television based entirely on the electronic principle, and in 1931 he created the world's first transmission electron tube with a mosaic photocathode, called an "iconoscope", which marked the beginning of the development of electronic television. The iconoscope was the first electronic transmitting television tube, which made it possible to begin mass production of television receivers. Next, Zworykin set about creating a completely electronic television system. Soviet scientists and inventors made a great contribution to the development of television - S. I. Kataev, P. V. Shmakov, P. V. Timofeev, G. V. Braude, L. A. Kubetsky, A. A. Chernyshev and others. In the second half of the 40s, the decomposition of the image transmitted by the Moscow and Leningrad centers was increased to 625 lines, which significantly improved the quality of television broadcasts.

If in 1953 only three television centers were operating, then in 1960 there were already 100 high-power television stations and 170 low-power relay stations, and by the end of 1970 there were up to 300 high-power and approximately low-power television stations. On the eve of the 50th anniversary of the Great October Socialist Revolution, on November 4, 1967, the All-Union Radio and Television Transmitting Station of the USSR Ministry of Communications came into operation, which, by decree of the Council of Ministers of the USSR, was named after the 50th anniversary of the October Revolution, the All-Union Television Center in Ostankino

Further development of television In 1954, the Moscow Television Center on Shabolovka carried out the first experimental transmissions with alternating transmission of color components. In 1956, in the laboratory of the Leningrad Electrotechnical Institute of Communications named after. M.A. Bonch-Bruevich developed and manufactured, under the leadership of P.V. Shmakov, a color television installation with simultaneous color transmission. In January 1960, the first transmission of color television took place in Leningrad from the experimental station of the Leningrad Electrotechnical Institute of Communications. In March 1965, an agreement was signed between the USSR and France on cooperation in the field of color television based on the SECAM system. On June 26, 1966, it was decided to choose the joint Soviet-French color television system SECAM for implementation in the Soviet Union. The first broadcasts on the joint Soviet - French system began in Moscow on October 1, 1967, the release of the first batch of color televisions was timed to coincide with this time. On the day of the 50th anniversary of the Great October Socialist Revolution (November 7, 1967), the first color television broadcast from Red Square of the parade and demonstration took place workers.

And the first remote control was created in 1950. This remote control was connected to the TV via a long wire. A few years later, Robert Adler proposed using ultrasound for this purpose. Attempts have also been made to use a visible light beam. But in the end they settled on infrared radiation, which is still used today.

Slide 1

History of television: from the first experiments to microcircuits

Presentation by Maria Kokorina 11c

Slide 2

The first stages of television development

For the first time, the phenomenon of the photoelectric effect - the release of electrons by a substance under the influence of electromagnetic radiation - was discovered by the German physicist Heinrich Hertz in 1887, and a year later the Russian scientist Alexander Stoletov conducted an experiment that clearly demonstrated this phenomenon. In 1907, the Russian physicist Boris Rosing managed to theoretically substantiate the possibility of obtaining an image using a cathode ray tube, developed earlier by the German physicist K. Braun, and even managed to put this into practice: he was able to obtain an image in the form of a single fixed point.

Slide 3

The first working television system is considered to be the invention of the German engineer Paul Nipkow, made back in 1884. The design marked the beginning of the creation of the so-called mechanical television. Paul Nipkow invented a disk with which images were converted into electrical impulses. It was a disk with a certain number of holes arranged in a spiral, opposite which a photocell was installed, and light fell on the photocell through this disk.

Slide 4

A patent for an optical-mechanical device for decomposing images into elements during the transmission and reception of television signals, called the Nipkow disk, was received in 1884. Nipkov rotated the disk over a picture or object. Light pulses penetrating through the holes of the disk were converted by a photocell into electrical signals. Then the number of lines on the screen was small - about 300, that is, light penetrated the object through three hundred holes, and the mechanically scanned television “picture” was rough.

Slide 5

Thanks to the Nipkow disk, in 1925 the Swedish engineer John Baird was able to achieve the transmission of recognizable human faces for the first time. Somewhat later, he also developed the first television system capable of transmitting moving images.

At first, the development of television went in two directions - electronic and mechanical. Moreover, the development of mechanical systems occurred almost until the end of the 40s of the 20th century, before it was completely replaced by electronic devices. On the territory of the USSR, mechanical television systems lasted a little longer.

Slide 6

How television broadcasting became widespread

Experiments using electron beams to transmit and receive images over certain distances began to be carried out in various countries from the early 20s. XX century. As a result, in 1933, an American engineer of Russian origin, Vladimir Zvorykin, managed to invent a cathode tube, which is still the main part of most televisions.

Slide 7

The first televisions suitable for mass production appeared in the late 30s of the twentieth century. However, this was preceded by several decades of persistent research and many ingenious discoveries.

Slide 8

At the end of 1936, the first electronic television suitable for practical use was developed at the American research laboratory RCA, headed by Zvorykin. Somewhat later, in 1939, RCA introduced the first television designed specifically for mass production. This model was called RCS TT-5. It was a massive wooden box equipped with a 5-inch diagonal screen. Later, radio tubes were replaced by semiconductors.

Slide 9

The first semiconductor-based television was developed in 1960 by Sony. Later, models based on microcircuits appeared. Now there are systems where the entire electronic content of the TV is contained in one single microcircuit.

Slide 10

Today, the quality of broadcasting has increased significantly and has become digital. TVs themselves have ceased to be perceived as “boxes”, because flat LCD and plasma models have appeared. Screen sizes are no longer measured at a couple of tens of centimeters. Television has become the norm. By the beginning of the twenty-first century, the methods and principles of television broadcasting had changed significantly. Cable and satellite television appeared.

Vakhabova O.V. History teacher at Penkovsky primary school

Slide 2

Invention of radio and cinema

Alexander Stepanovich Popov

May 7, 1895 – radiotelegraph
1919 – transmission of the first sounding word

Slide 3

Cinematography – Auguste and Louis Lumière

1895 – first movie camera

Slide 4

Nipkow disk 1884 (1923) first mechanical image scanning device

A rotating opaque disk, up to 50 cm in diameter, with holes marked in an Archimedes spiral - (“electric telescope”). The image was scanned with a light beam based on one (!) photocell, followed by transmission of the signal to a special converter. The number of holes ranged from 30 to 200. Behind the disk there was a neon lamp.

Slide 5

Mechanical TV

The screen glowed pink until the 40s. – green

The picture was blurry, in the form of shadows and outlines, “mute”

1930 A television laboratory was created at the All-Union Electrotechnical Institute; two radio receivers were required to receive television broadcasts

Slide 6

Start of production of mechanical TVs

April 15, 1932 Pravda newspaper: “The Leningrad Komintern plant began producing the first 20 Soviet televisions of the B-2 brand with a screen size of 3x4 cm”

The television was connected to a broadcast receiver instead of a loudspeaker.

Slide 7

First television broadcast

“Tomorrow, for the first time in the USSR, an experimental transmission of television (far vision) over radio will be carried out. From the shortwave transmitter RVEI-1 of the All-Union Electrotechnical Institute, an image of a living person and photographs will be transmitted at a wavelength of 56.6 meters."

More than 30 homemade televisions worked in the capital

The construction of the Moscow Television Center had not yet been completed; there was still no roof over the pavilion when test broadcasts of films began. The first took place on March 25, 1938 - the film “The Great Citizen” was shown. On September 5 of the same year, test studio broadcasts began. The act of completing the construction of the Moscow Television Center was signed on December 31, 1938, and regular broadcasting began on March 10, 1939. The receiving network consisted of 100 televisions installed within a radius of up to 30 km from the transmitter.

Slide 8

Cathode ray tube 1907

Boris Lvovich Rosing

Teacher at St. Petersburg Technological Institute
The cathode tube was invented by the Englishman W. Crookes and improved by the German scientist K. Brown
1911 – “privilege No. 18076” for the world’s first electronic television
1912 – gold medal and prize named after honorary member of the Russian technical society K.F. Siemens
1922 – state patent for “radio telescope”

Slide 9

First electronic TV

1925 Swedish engineer John Baird.
The first transmission of recognizable human faces and the first television system capable of transmitting moving images.
Late 1936 American Research Laboratory RCA. Vladimir Kozmich Zvorykin
The first electronic TV suitable for practical use (iconoscope)
1939 The first television designed specifically for mass production.
Model RCS TT-5 is a massive wooden box equipped with a 5-inch diagonal screen.

Slide 2

A little history

In December 1936, the RCA laboratory demonstrated the first television suitable for practical use. In April 1939, RCA introduced the first television set for general sale. All models were housed in handcrafted walnut cabinets.

Slide 3

By the early 1950s, a practical color television system had been invented. But it would be many more years before color television became the norm.
The gradual miniaturization of technology made it possible to make cases smaller and less intrusive, and screen sizes to increase.

Slide 4

1950s

The famous TV22 TV in a plastic case (1950s), manufactured by the British company Bush, embodied a “new look” at TV design, although TVs began to sell well in Europe only in the mid-1950s.
In the late 1950s, the American company Philco, inspired by the launch of the first Soviet satellite, used a futuristic style in the design of its televisions. Called the Philco Predicta, this space-age TV was one of the first to change the conventional cabinet-like look of the TV.

Slide 5

1960s

In 1960, the Japanese company Sony released the world's first transistor television, the TV8-301, followed by other portable models, such as the 8-inch Portarama Mk II (1962), made by Perdio.
In 1968, Sony introduced the first of its revolutionary Trinitron color televisions.

Slide 6

80s and 90s

Spherical TV.
In the 1980s and early 90s, televisions took on a more formal look. An example is the large-screen Trinitron from Sony.

Slide 7

Jim Nature TV designed by Philippe Starck (1994, for Saba), the body of which is made from pressed wood chips - an environmentally friendly alternative to plastic.

Slide 8

Modern TVs predominantly use high-tech style. An example is the widescreen BeoCenter AV5 (1997, Bang & Olufsen), with built-in CD player and radio.

Slide 9

How TVs work

In the kinescope of a conventional TV, the picture-image is “drawn” by a narrow beam of electrons, sweeping the screen line by line. Under the influence of electrons, a special coating (luminophor or phosphorus) applied to the screen begins to glow. Thus, at every moment one dot flashes on it.

Slide 10

On a “plasma” screen, each individual point (cell) is an autonomous luminous element. We can say that it is, in fact, an independent microkinescope, on the outer surface of which a phosphor is applied.
But its glow is caused not by electrons, but by ultraviolet radiation from a gas discharge occurring in the medium. . A plasma screen is a very complex structure. Each of its points represents a separate isolated cell, filled.

Slide 11

How does a kinescope work?

Now we will figure out how the video signal is transmitted. We will consider the SECAM system, because in our country (namely, the Russian Federation), this particular television system has been officially adopted.
It has a screen - 1 piece and a speaker - from 1 to infinity, depending on the “sophistication” of the TV. It also has an antenna and a control panel. But now we are only interested in the screen, i.e. kinescope (cathode ray tube - CRT). The picture on the screen is drawn using an electron beam. A bunch of electrons rush at breakneck speed in a straight line from point A to point B. This is how a “beam” is formed.
Point B is the anode. It's right on the back of the screen. Also, the screen (on the reverse side) is smeared with a special substance - phosphor. When an electron collides at breakneck speed with a phosphor, the latter emits visible light. Point A is an "electron gun". It is designed to fire an electron beam into the screen.

Slide 12

Electron gun

Diagram of an electron gun: 1 - cathode; 2 - modulator; 3 - first anode; 4 - second anode; e - electron trajectories.

Slide 13

CRT is a large electron tube

A lamp is a glass container from which air has been evacuated. The simplest lamp has 4 terminals: a cathode, an anode and two filament terminals. The filament is needed to heat the cathode. And the cathode needs to be heated in order for electrons to fly from it. And the electrons must fly in order for an electric current to arise through the lamp. To do this, a voltage of 6.3 or 12.6 V is usually applied to the filament (depending on the type of lamp)

Slide 14

Phosphor

The phosphor is applied in the form of sets of dots of three primary colors - red, green and blue. These colors are called primary because their combinations (in various proportions) can represent any color in the spectrum. The sets of phosphor dots are arranged in triangular triads. The triad forms a pixel - a point from which an image is formed (English pixel - picture element, picture element).

Slide 15

The picture on the TV screen is formed as a result of the fact that the beam draws at breakneck speed from left to right, from top to bottom across the screen. This method of sequentially drawing an image is called “scanning”. Since the scanning occurs very quickly, for the eye all the points merge into lines and the lines into a single frame. In PAL and SECAM systems, in one second the beam manages to run across the entire screen 50 times. In the American NTSC system - even more - as many as 60 times! Generally speaking, the PAL and SECAM systems differ only in color reproduction. Everything else is the same for them. The picture is formed due to the fact that during the “run” the beam changes its brightness in accordance with the received video signal.

Slide 16

What types of TVs are there?

Liquid crystal,
Plasma,
Regular,
Ceiling,
Portable,
Projection.

Slide 17

LCD TVs

Technical characteristics of Sharp LC-46XD 1RU6:

Screen diagonal (cm/inches) 117/46
Resolution 1920x1080
Brightness (cd/sq.m) 450
Contrast ratio 2000:1
Viewing angle (horizontal/vertical) 176/176
Response time (ms) 4
Acoustic power (W) 15x2
Screen format 16:9
Number of channels 100
There is stereo sound

Slide 18

Plasma TVs

Technical characteristics of Sony KDL-15G2000:

Screen diagonal (cm/inches) 38/15
Resolution 1024x768
Brightness (cd/sq.m) 400
Contrast ratio 500:1
Screen format 4:3
Availability of 16:9 format no
Viewing angle (horizontal/vertical) 170/170
Response time (ms) 16
Number of channels 100
There is stereo sound

Slide 19

Regular TVs

Specifications Philips 29PT8521/12:

Screen diagonal (cm/inches) 74/29
Sweep frequency 100 Hz
There is stereo sound
NICAM (stereo) no
Flat screen yes
Screen format 4:3
16:9 format available
Number of channels 100
There is a surround sound system

Slide 20

Ceiling TVs

Description of Mystery MMTC-1520D black:

Slim, compact design;
Built-in TV tuner: SECAM/PAL/NTSC;
On-screen menu and full-featured remote control;
Fast forward/rewind (x2, x4, x8, x16, x32);
Screen Zoom;
2 Video/Audio inputs;
Video/Audio output;
Built-in IR transmitter for wireless headphones;
Built-in FM modulator;
Built-in lampshade with three-position switch;

Slide 21

Portable TVs

Technical characteristics of Prology HDTV-909S:

Screen diagonal (cm/inches) 22.8/9
Screen format 16:9
TV systems PAL, SECAM, NTSC
Assembly location China
LCD matrix yes
no CRT
Color image available
Power (V) 12-13
Powered by batteries/accumulator no

Slide 22

Projection TVs

JVC HD-Z70RX5A Specifications:

Screen diagonal (cm/inches) 178/70
Sweep frequency 50 Hz
Screen format 16:9
Number of channels 100
There is stereo sound
NICAM (stereo) yes
Surround sound system
Acoustic power (W) 10x2

Slide 23

The role of TV in the educational process

Screen-sound means occupy a special place among other teaching aids. They have the most powerful educational impact, as they provide clarity, reliability, allow one to penetrate into the essence of processes and phenomena, and reveal them in their development and dynamics. Screen-sound means are a synthesis of a reliable scientific presentation of facts, events, phenomena with elements of art, since the display of life phenomena is carried out by artistic means (film and photography, artistic reading, painting, music, etc.). Influencing the senses with a complex of colors, sounds, verbal intonations, screen-sound means evoke a variety of sensations that are analyzed, compared, and compared with existing ideas and concepts. With the simultaneous influence of several stimuli, temporary connections are formed between the analyzers themselves, an association of sensations arises, which leads to an increase in emotional tone and level of performance. It is also necessary to emphasize that the use of screen-sound means has a positive effect on the organization of the educational process, giving it greater clarity and focus.

Slide 24

TV sales places

The shops:

"World"
"Technosila"
"El Dorado"
"M-video"
"Gorbushka"

Slide 25

Cost of TVs

Liquid crystal – from 130 thousand
Plasma - from 17 thousand
Regular – from 8 thousand
Ceiling - from 13 thousand
Portable – from 6 thousand
Projection - from 120 thousand

Slide 26

TVs of the future

The color rendering of future TVs uses the phenomenon of light diffraction. Each pixel will be represented not by three miniature RGB elements, but by a set of diffraction gratings made of a polymer that contracts under the influence of an electric current (artificial muscle). To improve reflectivity, one side of the grille is plated with gold. By splitting white light depending on the supplied electricity, the grating is capable of highlighting any color in the spectrum.

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Invention

TV.

Prepared by:

Student 4 "A" class

Dedyaeva Kristina

Since ancient times, humanity has dreamed of transmitting images over distances. We have all heard fairy tales and legends about magic mirrors, plates with apples and the like. But more than one millennium passed before this dream came true.

The first televisions suitable for mass production appeared in the late 30s of the last century. However, this was preceded by several decades of persistent research and many ingenious discoveries.

How it all started.

photoeffect

The era of television began after the discovery of the photoelectric effect. First of all, the internal photoelectric effect was used, the essence of which was that some semiconductors, when illuminated, significantly changed their electrical resistance.

How it all started.

The Englishman Smith was the first to note this interesting ability of semiconductors. In 1873, he reported on his experiments with crystalline selenium. In these experiments, selenium strips were placed in sealed glass tubes with platinum inputs. The tubes were placed in a lightproof box with a lid. In the dark, the resistance of the selenium strips was quite high and remained quite stable, but as soon as the lid of the box was removed, the conductivity increased by 15-100%.

In parallel, the development of televisions took place on the territory of the Soviet Union. The first experimental television broadcast took place on April 29, 1931. From October 1 of the same year, television broadcasts became regular. Since no one had televisions yet, collective viewings were held in specially designated places. Many Soviet radio amateurs are starting to assemble mechanical models of televisions with their own hands. In 1932, when developing the Second Five-Year Plan, television received a lot of attention. On November 15, 1934, a television program with sound was broadcast for the first time. For quite a long time, there was only one channel - the First. During the Great Patriotic War, the broadcast was interrupted and restored only after its end. And in 1960, Channel Two appeared.

Color television.

The first commercially available color TV was created in 1954 by the same RCA. This model was equipped with a 15 inch screen. Somewhat later, models with diagonals of 19 and 21 inches were developed. Such systems cost more than a thousand US dollars, and therefore were not accessible to everyone. However, if desired, it was possible to purchase this equipment on credit. Due to difficulties with the widespread organization of color television broadcasting, color television models could not quickly replace black and white ones, and for a long time both types were produced in parallel. Unified standards (PAL and SECAM) appeared and began to be implemented in 1967.

Development of television.

The rapid development of television in the second half of the 20th century led to the fact that several generations have already grown up who cannot imagine life without a television. The quality of broadcasting has increased significantly and has become digital. TVs themselves have ceased to be perceived as “boxes”, because flat LCD and plasma models have appeared. Screen sizes are no longer measured at a couple of tens of centimeters. Television has become the norm.