9 types of TVs: pros and cons of working principle

Among the receiving device and the transmission of images and sound TV has a special place in the minds of the mass consumer information. With the help of television one learns about the latest news in the country and the world, watch your favorite movies, TV shows and talk shows, having fun, playing games. Television programs have now become reliable, and for some the only source of useful information, broaden their horizons.

Modern color television operate by additive synthesis method RGB (Red, Green, Blue - Red, Green, Blue) color, the output color on screen occurs through addition of these colors with each other in accordance with the image forming technology implemented in everyday instrument.

The basic technology of forming an image:

• CRT (Cathode Ray Tube)
• LCD or LCD (Liquid Crystals)
• Plasma

CRT TVs

CRT or CRT TVs have long been the only type of videopriomnikov available to the user. There have been very popular, due to lack of technological alternatives. Of all the currently available types of TVs - the heaviest (40 kg). Screen size of 12 to 38 inches. Up to half a meter in depth. Operating time - up to 20 years. Angle - 160 - 180 degrees.

Advantages of CRT TVs:

• Long service life;
• Wide viewing angle;
• Low cost.

Disadvantages of CRT TVs:

• Heavy, enormous size;
• Low image quality;
• Staring at the screen, which increases eye fatigue;
• The sensitivity to magnetic fields;
• High power consumption;
• Only the analog signal.

The operating principle of CRT TVs
Formation of the display CRT TVs occurs under the action of a cathode ray tube which fires the electron beams on the phosphor layer of a certain color (red, green or blue) of this phosphor is lit - the screen is created Pixel 1 ms.

Blocks frame and line scanning the received radio block image divided into rows and elektroluch turns "maps out" on each screen. When the row ends, the beam moves to the next line, and similarly the vertical portrayal. This whole cycle repeats 25 times per second (25 fps).

For broadcasting characteristic interlacing: elektroluch first "draws" all the odd lines and then all even. As a result, 25 frames instead of 50 fields obtained. Field is generated at 20 ms, and the phosphor pixel is lit 1 ms, so long as "drawn" one line, the other begins to "fade" and the user sees on the screen the string running from top to bottom.

The image seems holistic because the nervous system device, which unconsciously remembers the previous line and recreated in the brain holistic picture. On the big screen flicker is clearly visible.

CRT TVs do not support high resolutions due to difficulties with the drawing of a geometrically correct image, why they are not popular in the age of DVD and FullHD. CRT glass is doped with lead to protect against x-best, which are created during deceleration of electrons in collision with lyuminiforom.

LCD TVs

LCD TVs - it is the most popular type of such devices, to judge by the number of purchases last year. Their dimensions vary from screens 12 to 65 inches, a portable model - from 5 to 10. The weight of the heaviest - less than 5 kg. Very thin - 3-5 cm. Long service life - 15-20 years.

It consumes less power 25 to 40 W / h, which is 2-3 times lower than the CRT. Screen LCD TVs covered by an anti-reflective layer to prevent reflections of light during use.

Viewing Angle important characteristic only for liquid crystal televisions. This criterion defines the maximum angle at which the screen image is transferred without loss of quality (preserves brightness and contrast).

Advantages of LCD TVs

• energy conservation;
• Space saving due to the intricacies of the case - can be hung from a bracket on the wall or ceiling;
• Anti-glare display;
• Small heat - up to 30 degrees Celsius;
• Long service life.

Disadvantages of LCD TVs

• Long response times;
• The viewing angle is less than that of plasma and CRT.

The operating principle of an LCD TV
The operation of the LCD device is a viscous liquid (cyanophenyl) consisting of the strictly ordered molecules. Under the influence of the electric field at the same time they change their position. When passing through their luminous flux, they polarize it. Over the last property cyanophenyl and called liquid crystals, due to similarities in the properties of solid crystals.

Luminous flux is created by the light source (from where it is located depends on the principle of operation of the LCD panel: the passage or reflection). In the fluorescent lamp of the cold cathode is used as such a source. Light passes through the first polarizing filter, then through liquid crystal layer to the control electrodes.

The electrodes creates a potential difference (voltage) whose value affects the level of turn-polaroids crystals, as a consequence, the angle of light polarization. The greater the latter, the brighter the light pixel on the screen. The light then falls on the second polarization filter disposed perpendicular to the first, and finally, after passing through the color filter, is displayed.

The higher voltage is applied the quicker turnaround crystals - less than RTT. The lower the response time, the video appears less blurred (image shift) on the screen. In order to make the response speed of the maximum response time compensation applied technology (RTC). its principle is to provide a pixel voltage with maximum amplitude.

The image on the LCD TV screen remains on the display while the other will not change (block change), because the screen pixels will never go out, but only a change of luminescence intensity.

LED-TVs

This LED TV, not led, as they are sometimes called marketing. They are a type of LCD. Weight - up to 3-4 kg, body depth - 2-3 cm. It consumes 40% less energy than LCD counterparts. Wide viewing angle - 170 degrees. Sizes range from 19 to 60 inches.

Capable of delivering high-quality image due to the absence of flicker and improvement (compared to LCD) dynamic contrast. Cost models of these devices is high. As of today - is the most technologically advanced and expensive type of the TV for the mass market.

The backlight may be placed over the entire surface of the matrix (carpet) and located only on edges of the screen (lateral). Side, is present on the thin and light housings. Carpet creates a more uniform illumination and can be adjusted for each area of ​​the screen separately.

In backlight LED displays used white and tricolor (RGB-triads) LEDs. The first economical in energy consumption, given the saturation of the second light and the contrast of the image.

plasma panels

According to research firm Futuresource Consulting, plasma display panels - the second in popularity among consumers view television. Screen sizes vary - from 40 to 80 inches.

Models with screens smaller hard to find on sale or they have too high a price for its features. Weigh no more than 6kg, even the best overall options. Wide viewing angle - 180 degrees, the service life of up to 15 to 17 years. High energy consumption - 70-160 watts / h. The cost depends on the size.

Advantages of plasma panaley:

• High image quality, especially color, dynamic and dark video scenes;
• Large sizes are beneficial in terms of price - quality;
• Long service life;
• Fast response time.

Disadvantages of Plasma:

• Without anti-reflective coating;
• High power consumption, uneconomical.
• Heated to 40 degrees and above

Lack of competitiveness, according to the manufacturer, due to the fact that people do not buy them, preferring LCD device, since plasma displays do not support the high resolution (more than FullHD), heated and spend a lot of energy.
Principle of operation
Plasma panels are so called because of its structure and method of forming the image. The image is formed from glass panel capsules, which contain a mixture of inert gases (neon and xenon). The rear wall of the capsule comprises a color phosphor layer (red, green or blue). At each pixel have three capsules.

By means of electrodes in the cell (capsule) is fed an electrical charge that acting on the gas mixture ionizes it. The ionized gas (plasma) emits X-rays, which act on the corresponding phosphor layer, causing it to glow. When combining the luminosity of the three cells obtained pixel.

Since the voltage across the electrodes is supplied with a switch serially rather than all at once, the screen flickers in plasma display panels as a CRT. This problem is solved in the same way - the increase of the surplus frequency (display frame).

In modern devices the frequency reaches 400 Hz. Phosphor degrades with time, which affects the image quality, so the service life of the equipment is lower than that of liquid crystal counterparts.

Digital DVB-T2

DVB (Digital Video Broadcasting) - is a set of digital television standards, which were developed by an international consortium DVB Project.

There are three types of standards:

• DVB-T; terrestrial TV standard.
• DVB-C; cable television standard.
• DVB-S; satellite TV standard.

For the TV to take, to "understand" and reproduce video and audio transmitted in accordance with one of these broadcast standards, it is necessary to set corresponding standard decoder (tuner).

DVB-T, more precisely, its upgraded version - DVB-T2 is inserted into its TVs, many manufacturers. they do is guided by a great demand among buyers. After buying it is not necessary to pay for cable or satellite TV every month or year. Just connect and enjoy free TV, with no additional hardware. DVB-T2 tuner receives a digital signal by a conventional antenna, and decodes it in the HD-quality video.

The advantages of the installation:

• A large number of broadcast channels (from 20 to 100, depending on the broadcast zone);
• The digital signal is more resistant to distortion than analog;
• High quality images and sound (HD-quality).

4K TVs

According to Alan Crisp, analyst The NSR Corporation, for 4K - the future. The productive panel capable of reproducing video UltraHD format are already available on the market.

According to the minimum requirements adopted in October 2012 Consumer Electronics Association (CEA) every 4K (UltraHD) televisions must comply with the following characteristics:

• Display resolution - not less than 8 million pixels, 3840 2160 horizontally and vertically.
• Aspect ratio - 16: 9.
• Upconverter - HD image scaling ability of the video and display it with UHD resolution.
• Digital input - one or more HDMI inputs with support for content with a resolution of 3840 × 2160 with 24p frame rate, 30p and 60p frames per second.
• Colorimetry - the ability to handle 2160p video with ITU-R BT.709 color space and standards support with a wider color space.
• Depth of color - at least 32 bits

Yet 4k Blu-ray discs and television channels broadcasting in ultra-high quality, such a device will remain a curiosity rather than a useful device.

But now the video to 4K panel FullHD looks sharper than any other, thanks to quadruple the number of pixels.

Screens with ultra-high resolution are suitable:

• To view pictures taken digital camerasWhich remove at high (3200h2400) resolution;
• computer games and the maximum effect of presence;
• viewing 4K films;

Smart TV TVs

TVs with Smart TV function (Smart TV) - High-tech digital devices fitted with the operating system, network interfaces and necessary software tools. This technology is designed to connect the home TV and Internet resources through computerization of the domestic appliance.

The network interface on SmartTV - presented network equipment (Ethernet or Wi-Fi modem) Embedded in the body and a special network software is a component of the operating system.

The necessary software tools (applications) are:

• Browser (Internet browser); the user can browse the web, communicate in social networks, upload files, configure and update device.
• Application with access to store additional applications; Download useful programs (weather forecast, exchange rate).
• Built-in audio and video player; to listen to the radio, or songs downloaded from the internet, watch videos on YouTube, movies in the global or local network.

Additional software, as well as online store, as different models of different brands.

This is, firstly, creates competition, and, secondly, the difference between the projecting lasting functionality software components. Some Smart focuses on social networks, in other videos.

The main problem, judging by the reviews in the shops is inconvenience remote controls for the implementation of laid down in the SmartTV features. Communicate in social networks and manage your page uncomfortable.

Therefore, technology developers with support for this technology are focused on ease of remote control by making it to the a joystick control units traditional console functions (channel switching, volume control and so on. d.) and keyboard units and mice.

3D TVs

3D technology can be implemented on plasma and LCD panels. This technology is not imaging and output. A man sees a set of real-world objects with each eye in a different plane to the brain information from the eyes connected and creates a complete image of the three-dimensional image.

This vision is called binocular or stereoscopic. This property is used and in 3D. The screen displays two planar images taken at different angles, which with the help of special tools (external or on TV) are perceived through the eyes and brain merge into a volumetric image.

Methods stereoscopic image display:

• active method
• passive method

With the active method on the screen within 20 milliseconds stereoframes two sequentially transmitted. The human eye perceives them as one of the output speed. That each eye perceives intended for it a frame sync used glasses with shutters on each eyepiece. When the output frame for the right eye, left eyepiece shutters closed, when the next frame image is not visible to the right eye.

Disadvantages are the high cost implementation of this technology, which is reflected in its cost and load on the supporting device eyes due to switching from one activity to another.

In the passive, 3D image is divided into two fields. Both are simultaneously displayed on the screen vertically (side by side) or horizontally (one over another). One frame is intended for the left eye, the other - to the right. This is accomplished by using glasses with polarizing filters in eyepieces, do not give the right eye to see the picture to the left and vice versa.

Advantages of this technology is that it is inexpensive and applied in 3D glasses does not tire the eyes.

The downside is that the separation of the image, its resolution is halved, respectively, and reduced image quality.

Included with the purchase of the advanced 3D TVs are several pairs of glasses, with the wireless synchronization with the TV through infrared radiation. In the glasses is a chip, it is necessary to timely correct lens shading.

cheap TVs

This conditional category. What cheap for one person to another can be a daunting amount. Line TVs in shops are divided by the size of their screens and the presence of additional devices. The price of some models on the order below, and they are called low-cost options.

Diagonal 15-24 inches

Among the 15 inch on the market you can find LCD model with a resolution of 1366x768 pixels and brightness up to 500 cd / m2, a high response time, often with built-in USB connector, which can be inserted flash card. Cost - 120-130 dollars.

Diagonal 23 - 29 inches

cheap monitors and televisions this category there are about 200 - 250 dollars. Available with a resolution of 1920x1080 with HDMI and USB slots, support HDTV, a minimum set of functions and weigh up to 2 kg and uncomfortable software settings menu.

Size 32 -37 inch

Cheaper models with a screen of this size will be - 400 dollar TVs. A good choice would be a device display HDMISupporting FullHD at 1920x1080 resolution, contrast ratio of 100,000: 1, 3,5-4s response time, a brightness of 700 cd / m2. To this you can connect the game console.

If we consider the device in which the screen is larger than 40 inches, the user will not find options with a price below $ 700. If such price is right, you can count on a TV with the operating system, lightweight cotton with 20-25 stereo contrast ratio of 500,000: 1.