Television set

A TV or TV in the 1930s or the Ferntonkino Telehor ( from Ancient Greek horao = see '), is a device for receiving and reproducing television signals. The idea for a first mechanical television was demonstrated in 1886 by Paul Nipkow in a patent. It is considered therefore as the actual inventor of television. Commonly used for televisions is also the name of the television receiver.

In allusion to the beginning nor easily perceptible flicker of motion pictures of the TV is often colloquially referred to as a boob tube. Other colloquial names for the TV are television, goggle-box, tube ( for older devices after the picture tube ), ground glass, seat movie and telly.

  • 3.1 100 Hz CRT TV
  • 3.2 100 -, 200 - and 600 - Hz flat-panel TVs
  • 3.3 Digital image signal improvement
  • 3.4 Digital TV Reception
  • 3.5 High -definition television
  • 3.6 3D TV
  • 3.7 TV as a media center and internet connectivity

Playback options

The reproduction of images on the TV is carried on a screen. The use of video projectors as TV ( as " home theater " ) is another possibility. With a TV card and the monitor of the computer can be used as a TV. There is also transmission capabilities on the Internet or via the broadband cable, where the computer is used as a receiving device.

The most important in addition to the image display system is part of a television tuner which converts the analogue or digital radio frequency signals from the cable, the antenna or satellite input into a video signal. For connecting other video systems (eg, DVD player, DVB- T tuner, satellite receiver ) is at European appliances usually have a SCART socket is available, and for digital signals DVI or HDMI connectors. The reproduction of sounds via speakers that can stand outside of the device.

At the beginning of television history were black and white devices that could reproduce grayscale images only, before the technical development enabled television sets. Meanwhile, the trend towards devices that can also reproduce three-dimensional images is (3D - TV).

Worldwide several different television standards were developed with different image resolutions that are designated with single letters from A to N for analogue television. The basic different color transmission standards are PAL, SECAM and NTSC. In German-speaking countries are currently (today, Booth 2012, only the analogue cable TV ), the TV standards B for VHF transmitters and G for UHF channels as well as the PAL standard for color transmission used accordingly it is called PAL -B / G. In digital television, this standard differences are out of the picture resolution is no longer important.

The so-called 100 -Hz television sets the first field is stored each image and then displayed together until the second field; then both are repeated once more during the first field of the next frame is received already. As a result, each image is shown twice to make the image flicker disappears completely subjective. For fast-moving images, however, is quite complex digital post-processing of the images in the device needed ( so-called deinterlacing ) to avoid artifacts caused by the altered timing of the image representation.

The TV is operated nowadays almost exclusively via an IR remote control. With a commonly existing hotel mode, certain settings can be disabled.

Since the late 1970s, the TV no longer served the needs of television. With the gradual introduction of the new media, VCRs and DVD recorders have the greatest reputation, the TV was also a screen for external media.

Types of televisions

In addition to the tube TV sets and flat-screen TVs described in detail below other display techniques for television sets are used.

  • Rear projection screen
  • Video Projector
  • Using TV card may also be the computer to the TV and thus the necessary screen be used for display. In recent use, the data transmitted via the Internet television signal is ultimately a variant of the computer in the sense of use of a television set.

Tube device

Until a few years ago was the term " television " basically a so-called tube apparatus understood where the term tube refers to the main component, the picture tube. This is their construction after a Braun tube, named after its inventor, Karl Ferdinand Braun. This tube is made of a stationary vacuum funnel-shaped glass container, in which more or less depending on the desired brightness of a pixel, electrons are accelerated ( the actual screen) towards the cathode in the trailing picture tube neck forward towards the anode and excite the applied there luminescent layer.

The high voltage on the anode is typically recovered from the line generator and high voltage transformed from 6000 to 33,000 by the line output transformer may vary depending on screen size. The picture tube interacts with their inner and outer aquadag coating as large capacitor and maintains the high voltage even for some time after switching off the appliance and could represent a serious hazard. Due to the low power voltage for these people is not fatal in general; but it comes at a touch too jumpy strong muscle movements that can pull secondary bodily injury and property damage by itself. Therefore, working inside should always be performed to a television only by trained personnel.

A heated metal tube used in the picture tube as a hot cathode. From this will be a 400 to 1000 volts positively charged grid (G2 ) (positive means lack of electrons ) electrons torn punctiform. A slightly negatively charged cylinder ( Wehnelt ) allows control of the amount of electrons, which corresponds to a control of the pixel brightness. Another electrostatic lens system ( 3-4 kV) regulates the focus ( size and sharpness of the image point ). Overall, the compact kinescope electron system is very similar to an optical lens system with an iris and a light source.

Without further Ablenkvorkehrung the electron would be accelerated by the anode screen towards center of the screen, just leave a single bright pixel in the applied to the back of the screen phosphor phosphor layer - and damage the layer immediately by a Einbrennpunkt. Two on the picture tube neck 90 degree staggered deflection of electron beam is guided into the desired line number and frame rate by two sawtooth deflection across the screen. Normally, the electron beam is moved line by line from left to right and top to bottom on the screen, and thus results from the different brightnesses of the image. The repetition of a complete process (for example, the screen layout ) is measured in Hertz (Hz) (Example: 100 Hz = 100 times per second). The horizontal deflection is coupled generally in line with the high-voltage generating transformer. In case of failure remains by eliminating the picture tube anode high voltage from a damaging Einbrennfleck; failure of the vertical deflection unit is created on the screen of the characteristic horizontal bright line.

In the early days of television ( 1930s and 1940s ) and the electrostatic image deflection was used. Here, two are located at an angle of 90 degrees offset from each other condenser plates in the neck of the picture tube between which builds up an electrostatic field at a high voltage, which deflects the electron beam. Because - with acceptable deflection voltages - so only maximum deflection angle of about 40 degrees can be achieved, had later the electromagnetic deflection enforced with deflection coils, with the deflection angle of over 110 degrees are possible.

In color television sets, there are three slightly staggered cathode for the three primary colors red, green and blue. A mask in the form of a fine metal grid just behind the ground glass ensures in this case that the electrons can be taken by each cathode fluorescent spots only on "their" color. The remaining electrons stick to the mask. Since most of the electrons therefore never reach the screen, the acceleration voltage needs to be much higher than in a black -and-white device in a color television receiver with the same image brightness. The fluorescent layer is in this case made ​​of adjacent small dots or stripes of three primary colors. These elements can be seen easily if you look at the screen from a short distance.

Flat equipment

The conventional tube televisions were replaced in the 2000s by increasingly flat-screen TVs. These are based on the flat screens and otherwise used.

In 2006, more flat-screen devices were first sold in Germany than conventional tube sets. In 2007, more flat-screen TVs were sold as tube sets for the first time.

To be HD-ready compliant, at least 720 image lines are needed. HDTV is the worldwide established standard for high definition television. It is common, for example, in North America and East Asia right. HDTV-ready tube TVs existed in Germany from JVC, Philips and Samsung. 2008 almost all manufacturers had ceased production of CRT TVs; Philips was considered the last European manufacturer (until 2011 ).

The image quality and the correct image adjustment of televisions can be using test patterns judge.

Techniques

Divided according to the technology used for the flat panel display, a distinction is

  • PDP televisions (English Plasma Display Panel ) with plasma screens
  • LCD televisions with liquid crystal displays ( LCD) with traditional fluorescent tube backlight.
  • LED TVs - erroneous designation for LCD screens with LED backlight to optimize the picture and power consumption.
  • OLED TVs with OLED screens so far (as of early 2011 ) is hardly relevant to the market and mainly in the prototype stage.
  • SED televisions with Surface - conduction Electron - emitter displays. They combine the advantages of plasma ( self-luminous, true black, inertia ) and LCD ( low energy consumption ) to take over without their disadvantages. Each pixel consists of a tiny electron source with an accelerator unit, but which causes x-ray radiation. Production and market introduction were postponed indefinitely.
  • FED televisions with field emission displays. Related to SED. Development discontinued due to lack of funds.

Benefits

  • The main advantage of flat screen technology is considerably lower unit depth of a few centimeters, which is independent of the screen size. In contrast, CRT televisions need more depth of up to about 60 inches with a larger screen.
  • The interlace mode used when " tube TV " to avoid line flicker is no longer necessary with flat-screen TVs. Flat-panel televisions "write" images in full screen method. Interlaced variety of video material is therefore in front of a display on flat screen digital to full screen ( progressive scan) converted. This occasionally caused display problems (comb effects).
  • Modern flat screen televisions drive a high computational cost for digital image enhancement; at low -priced devices, the image quality for the same reason is somewhat lower.
  • An improvement in the image quality brings with modern flat-screen televisions to increase the frame rate of 50 Hz ( 50 fields interlaced result 25 frames ) to 100 Hz, 200 Hz or even higher frequency.
  • Digital equipment technology provides numerous opportunities to increase the use-value. For example, the disturbing ambient light are measured at LCD televisions with a sensor in the screen frame and used for the readjustment of the image intensifier and thus contribute to improve the image ( increase contrast ). Tube sensors are not suitable for such manipulations and were not fitted because of the expense associated with the tube technology with such features.
  • Plasma technology is, however, particularly for large flat panel displays. Plasma TVs dominate short pixel switching times better than LCD TVs. Therefore (as of 201x ) plasma 3D displays can represent the spatial 120Hz 3D video signals, as with 3D Blu -ray discs with significantly less left-right crosstalk ( ghosting ) as a 3D LCD screens.
  • The low weight, which also allows a direct mounting on walls and meets the earlier vision of the future " TV which can be hung like a picture on the wall ".
  • Flat-screen devices often have a higher image resolution and displayable are also capable to accept HDTV signals, while this is true for tube equipment to last only a few models.

Disadvantages

  • Flat-panel devices offer less resonance chamber for the sound (more precisely, the speaker cone of the woofer ). The sound quality of many devices is inferior to that of a CRT television with good speaker chassis.
  • LCD televisions still have a certain dependence of the image impression (brightness, contrast, color) from the angle of the viewer to the television; Had plasma TVs and this never have.
  • Many LC - screens - especially those with cold cathode lamp - can be inherently not the usual television image of similar black level represent, therefore (no light ) instead of the true black only a dark gray (often with a bluish strike) possible. Remedy is managed by LED backlight, which can be dimmed or switched off in dark image areas.
  • Plasma screens consumed earlier in relation to LCD technology, a lot of power.

Former disadvantages

Before about 2007, most had flat screens over conventional CRT monitors some disadvantages:

  • For fast-moving images (but not plasma screens ) LC - screens showed blurring, referred to as ghosting or motion artifacts, sometimes called comet tail. This was due to over CRTs high pixel switching times of more than 20 ms. Nowadays pixel response times of 8 are - 2 ms usual so that the problem no longer exists.
  • Bright stationary image areas such as station logos tended - in particular with plasma screens - for baking.
  • Flat screens have a fixed pixel grid ( image resolution, such as HD or Full HD); when displaying images that differ from this grid, a conversion (scaling) must be made. Earlier it was doing to artifacts and loss of image quality. Today the Scalerchips are better and have a higher processing power.
  • Lower life. Individual TV technician believe that some manufacturers the life of flat panel TVs artificially under 10,000 hours of operation limit ( Planned Obsolescence ).

Unique Technologies

100 Hz CRT TV

Due to falling prices for memory chips (RAM) 100 Hz TVs could be offered at a reasonable price from approximately 1988. By temporarily storing a video field and reading of the image information at double speed ( 100 Hz instead of 50 Hz ), it was possible to eliminate the problem at normal televisions turbulent flickering of the image (see also: the 100 Hz technology). However, the price was required in all such television receivers consuming deinterlacing technique for now flicker-free 100Hz image since the interlacing could no longer be applied by analogy to the phosphor layer of the picture tube and the eye of the beholder.

100 -, 200 - and 600 - Hz flat-panel TVs

The 100 Hz technology, which is used comes with flat panel TVs, is different despite identical designation fundamentally from the tube sets: A processor in the device calculates additional intermediate pictures, so that eventually up to 100 images per second (at 100 Hz technology and are presented input signals at 25 frames per second) (see also Motion interpolation). This is to ensure smoother movements especially in fast motion in the picture (for example, sports or action scenes ). Analogous work the 200 Hz technology that will not increase the advantages of the 100 Hz technology. However, is criticized in these technologies that can occur during the inter-frame calculation to image defects in the form of artifacts and image blur. In addition, the motion smoothing is perceived by some observers as unnatural (so-called " soap opera effect"). Some manufacturers offer plasma televisions with 600 Hz technology, this does not involve, however, a " real frame rate " of 600 Hz Instead, between the images ( original and additionally calculated ) even inserted a black screen and then the number of 600 " images " obtained per second.

Digital image signal improvement

Standard Elektrik Lorenz (SEL ) presented in the fall of 1983, new digital televisions under the name " Digivision ". Having an idea of the Yugoslav engineer Lubo Micic intermetallic Freiburg was therefore developed in 10 years of development novel integrated circuits, which allowed a fully digital image processing in the TV for the first time. To an analog video signal received in the digitized television, digital enhanced, and then converted on the output of the further analog picture tube back into an analog signal. In addition to a digital image enhancement as well as a digital set various other parameters of a TV image as geometry or color reproduction was possible. The approach was to ensure, above all, a constant over the lifetime of the device image quality.

Since the receive path and further resources analogous and thus error-prone wasting, was thought at that time intensively on a digitization of the receive path.

Digital TV Reception

First steps on the road to digital television reception were TV - SAT and D2 - MAC. During this European 16:9 format, the image was still analog, but the sound transmitted already digital multi-channel. Because of relatively low prevalence of receivers and high additional costs for the production and broadcast via satellite dissemination ran after a test phase with the high-resolution variant of HD-MAC mid-1990s gradually made ​​.

The digitization of television has occurred since that time in two parallel separate areas.

Televisions with digital processing as well ( digital ) flat panel displays are now considered standard. Fully digital televisions - they have next to digital reception and digital internal processing and a digital display - called IDTV.

High definition television

Since the mid- 2000s, see higher resolution flat-panel displays for television reception becoming increasingly widespread. Prerequisite for the enjoyment sharper images are HD-capable devices (receiver, recorder, player ) and produced in HD program material. Most newer flat screens have been built tuners for digital TV reception of HDTV channels. The home system is supplemented usually with a Blu- Ray player, which in general can also play DVDs in better quality.

3D TV

Since the 1950s, there are 3D movies in theaters. Background of the development was the increasing popularity of home television. The film industry was looking for innovations to improve the attractiveness of cinema for the audience again. The farbanaglyphe space image projection for this seemed an appropriate way. This is where a film is first recorded using stereo cameras, which - results in two slightly offset from the image viewing angle impressions - like the human eye. When playing back an image was red - right eye - and an image of green - left eye - inked and rendered on the same screen. The spectators wore special glasses with one red and one green filter of each eye. So got each eye to see only one image, which were composed as in normal vision to a spatial perception - but related reasons, only in black and white. Because of the necessary color reproduction, this process could then be applied only in the cinema, as home televisions could only represent black and white images. After the advent of color television these color anaglyph technique was again used in the 1980s for experimental 3D broadcasts in the third TV programs. However, the low bandwidth of the analogue PAL TV color channel decreased the necessary resolution and sharpness of the received 3D image so strong that no satisfactory spatial impression came about and the experiments were terminated.

In the late 2000s, a similar pattern repeated. Part of cinema took increasing competition from the private home theater equipment, DVDs and Black copies from the Internet as an opportunity to introduce a new digital 3D technology. Through new digital recording and projection methods, the spatial image is now higher resolution and in color. When used for this technique, the audience shutter or polarization glasses or " Dolby 3D" wear glasses after Infitec method. For many moviegoers, published in December 2009, the film was Avatar - Film Title, the first movie they saw in 3D.

Even television manufacturers are working on 3D playback devices for the home theater using digital "high- definition " technology with the " Blu -ray Disc " as the media. Beginning of 2010 brought several companies televisions and video projectors on the market, which can be used at home watch digital 3D movies. This requires a 3D active shutter glasses is needed, which synchronizes with the fast image change cycle of the 3D screen ( 100 or 120 Hz) via infrared or radio signals. According to a study BITKOM autumn 2010 to be purchased with 3D technology by 2015 in Germany around eight million television.

Some providers also offer devices with passive polarizing glasses. At IFA 2010, a large cinema screen of LED arrays existing display was presented, which was circularly polarized by means of special films.

Also at IFA 2010 showed several manufacturers 3D screens, for which no special glasses are needed, so-called autostereoscopic displays. For this purpose the screen - like flip images - provided with vertical stripes of micro prisms so that different images reach the two eyes. This, however, the viewer has to sit still; each movement can interfere with the impression. Some providers can operate not only a visual axis, but several. At the trade fair CES in Las Vegas in January 2011, three companies commercially available autostereoscopic 3D displays are presented. Some of these presented equipment could "serve" up to seven lines of sight simultaneously with 3D images. The first commercial operations are in particular in the field of outdoor advertising, ie digital signage, gaming and demanding PC applications such as CAD. The screen size varied between 56 cm (18 inches) and 165 cm (65 inches). Since July 2012, is also available outside of Japan with the Toshiba 55 Zl2g the first TV with this glasses-free 3D technology as a large-scale device. The screen size is 140 cm ( 55 inches ); the resolution " 4K " (four times more pixels than Full HD).

A glasses-free 3D technology - autostereoscopy - comes as the first 3D video cameras ( Fujifilm, Sony) already in the portable video game console Nintendo 3DS to use that will allow according to the manufacturer also watch 3D movies on the palm-sized screen. The manufacturer said precaution from a health warning for children under six years old and older people. Some eye doctors expressed that there is no scientific evidence of harmful effects of 3D images.

Some of the provided 3D TV and 3D Blu -ray player can convert 2D TV images in real time in 3D. The method is based, for example, that the device detects where the camera was in focus during recording. The 3D effect is not comparable with the turned of in digital stereo 3D movies. Thus, the 3D effect is, for example, limited to the back, and the action seems to play more in different image planes, instead of continuously acting space.

As players for 3D material, there are 3D Blu- Ray Player, Digital Satellite Receiver and multimedia player. All satellite receiver can play the 3D signal emitted as these in SBS ( Side-by- Side ) process to work. Current multimedia hard drives give 3D Blu -Ray ISO files again; thus can be played easily backup copies of 3D Blu -ray discs.

SES Astra sent during the IFA 2010 a 3D demo channel on which reports and information broadcast by the IFA.

There are now several European TV satellite different 3D HD demo channels, all in side-by -side mode. The Sky pay TV chains in the UK and Germany have a 3D event channel with sports, shows and movies respectively.

TV as a media center and internet connectivity

As part of the progressive digitization of the art television receiver grow more and more in the direction of fully functional All- in-one computer. For most Asian manufacturers of conventional television this means declining revenues and years of losses in a row.

Modern televisions are equipped with ports for USB storage devices, and the most common memory card and may differ from these media data, such as DivX, Xvid, MP4, Nero Digital or WMV9 format to play. In addition, they often have an Ethernet port or Wi-Fi antennas, with which for example, receive video streams and can be played.

For optional sound modern devices often have an additional optical or coaxial digital output. With the appropriate digital cables can be connected to a suitably equipped AV receiver, which among other surround-sound playback is possible.

About Wi-Fi Internet connection is often realized, which allows you to call any websites with an integrated web browser, or to use different provided by the television provider TV apps and widgets. These applications may also be suitable for the web radio, streaming client or as a DLNA client. Such televisions that are increasingly interactive designed and equipped with Internet capabilities are often performed under the name Smart TV.

There is a clear trend towards the convergence of technology of television receivers and personal computers. With the VGA and the HDMI interface, existing computers and modern televisions together.

Also of the personal computer side there are more and more devices that have been made in the all- in-one construction from design and through the media center software forth " living fit " and in this way the complete range of functions of a TV offer and a PC. Another way to televisions to expand smart TV functions, the so-called HDMI connection of sticks over the existing HDMI interface.

Image resolution of each device generations in German-speaking

Viewing distances and screen ergonomics

Although television and auxiliary services such as the Internet, both on television sets as well as on computer workstations can be displayed and applications both merge and are no longer clearly separated, here are several recommendations for the best viewing distance.

Television differs from reading also the fact that the viewer or audience ( TV / Radio Seer ) turns his attention not only on a small detail of a representation, but mainly to an overall picture. This is usually moved while watching TV. In contrast to reading a minimum viewing distance to the screen is recommended when watching TV. This minimum distance was based originally ( when there were only 4-3 screens ) to the selected screen size and resulted in part from the otherwise disturbing perceived line structure of the image. Since the existence of 16:9 screens and the predominantly existing digital television is recommended minimum distances emanating from the image height. This avoids an otherwise necessary distinction between 4:3 - and 16:9 screens. For normal resolution television ( SDTV, PAL ) Minimum distances of six times the picture height and HDTV are recommended minimum distances from the three to four times the picture height. Thus, the human eye can follow an entire image impression while watching TV one hand without effort and on the other hand also come ( HDTV ) to enjoy a cinema feeling.

On a (to read optimized ) computer workstation other criteria that predominantly based on the font size are shown. If such a work for television use, so the viewer should increase its distance from the screen or open on the computer screen, a correspondingly smaller program window for the video.

An alternative for the readability of text on the screen in the usual viewing distance to the TV is to display it in the great scriptures, as in teletext. Usually formatted web pages require higher resolution screens and / or of corresponding size.

Immunity from seizure in Germany

According to § 811 Paragraph 1 No. 1 ZPO a TV is not subject to seizure, even if next to a radio device is present ( BFH NJW 1990, 1871). The reason for this is that the debtor would be deprived of his constitutionally protected way without a television, to learn from generally accessible sources on world events. However, exceptions may occur as part of the so-called exchange garnishment.

Known manufacturers of televisions

In the vergangenehen decades, the production of televisions shifted increasingly from Europe and North America to Southeast Asia (especially South Korea and China). Even companies such as Philips, which have their headquarters in Europe still is possible to produce in China. In particular, also reported a number of German companies on bankruptcies.

  • Japan AOC
  • Turkey Arçelik
  • Germany Blaupunkt
  • People's Republic of China Hong Chan
  • Japan Funai Electric
  • China Republic of HannStar Display
  • China People's Republic of Hisense
  • JVC Japan
  • Italy Lenuss
  • Germany Metz
  • Japan Mitsubishi Electric
  • Japan NEC Corporation
  • Hungary Orion Electronics
  • Japan Panasonic
  • Netherlands Philips
  • Japan Pioneer
  • Japan Sharp
  • Sony Japan
  • China Republic of Tatung
  • China People's Republic of TCL
  • Germany TechniSat
  • Japan Toshiba
  • Germany Wortmann
  • United States Zenith
  • Germany Grundig
  • Germany Körting
  • Germany Cuba Imperial
  • Germany North Mende
  • Finland Nokia
  • Germany Rafena
  • Germany RFT
  • Germany SABA
  • Germany Schneider
  • France Thomson
  • Germany Telefunken
  • Germany Wega
Electronic visual display Home cinema Digital Visual Interface Broadcast television systems Compression artifact Peredelkino 7JP4 Sawtooth wave LED-backlit LCD display Surface-conduction Electron-emitter Display Image scaling Integrated digital television Digital movie camera Digital Living Network Alliance History of television HD suisse Moser Baer Panasonic (brand) Tatung Company Vestel Graetz AG Nordmende SABA (electronics manufacturer) Technicolor SA History of television in Germany Chip (magazine)
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