The problem of choosing a high-quality liquid crystal TV: Main parameters and design features of devices.
42 and 47 inches. Finish with piano varnish. Matrix resolution 19201080p
(Full HD), viewing angle 178. HDMI input, SRS Trusurround XT surrounding system
Loewe Individual Compose. Built-in high definition television tuner (HDTV), hard disk (DR +), HDMI connectors (2), USB 2.0
Compactness and attractive design- Here are the main trumps of flat TVs. Their LCD varieties successfully overcomes growth disease and is becoming increasingly demanded by buyers. We will tell you this article, how to choose a high-quality LCD TV, what is its device and basic parameters.
15-inch TV with a resolution of 1024768p. Crystal Clear III Technology, Virtual Dolby Decoder Another 10 years ago the word "TV" was associated with Kinescopic devices - CRT TVs (English CRT TV). Now most manufacturers have ceased to release them, because they prefer to actively earn on the sale of plasma (PDP) and liquid crystal (LCD) models. Plasma provide a good picture, but not by pocket, most of our fellow citizens - prices for decent devices start from 100 thousand rubles. LCD TVs until recently cost about the same amount, but at the same time they gave a very mediocre image. According to experts, morally outdated kinescopic TV and today are superior to LCD televisions for a variety of parameters, unconditionally losing only in dimensions and mass.
Less yes better
Despite the desire of developers to create flat kinescopes of shallow depth, to acquire the device weighing 60kg now almost no one wants to anyone. Most of the potential buyers are facing TVs with LCD displays. If only 2-3 years ago, they only occupied a small niche among devices having a diagonal up to 15-19 inches, now you can meet a lot of TVs with a screen diagonal of 45 inches and a resolution of 1920 1080 pixels (models of HDTV Ready). These devices not only allow you to watch TV shows, but also able to take an honorable place in the home theater.
Two types of permission
It is necessary to distinguish between the resolution of the video signal (in the lines of the TVL and pixels) and the physical resolution of the display (in pixels). For example, 720576 lines (PAL) and 1368720 pixels. The resolution of the analog signal (quadudates, ether) adapts to the physical display. Digital video signal must match the capabilities of the screen. If the resolution of the signal is greater than the display allows, the TV will not be able to demonstrate the advantages of high-resolution video. AESLI on the contrary, then when scaling will decrease the image clarity.
How is it arranged?
The LCD abbreviation is decrypted as Liquid Crystal Display and indicates that the display of this TV runs on liquid crystals. Hence the generally accepted abbreviation. For the first time, a working sample of the LCD display was demonstrated in 1972. In the United States, although the principle of operation was discovered much earlier. The span of pores have changed many technologies that allowed to improve quantitative (sizes) and high-quality (image) LCD indicators. Most modern LCD TVs are based on active matrices on TFT microtransistors (English. Thin Film Transistors). Such matrices are characterized by high speed (response time for a feed signal) compared to passive matrices of previous generations. Modern TFT matrices provide smaller distortion during quick changes in the picture.
1- polarizer-filter transmitting light waves of one orientation (used to obtain an image when reorienting crystals under the influence of voltage);
2-transparent control electrodes of LCD molecules transparent materials are used to minimize color and brightness losses);
3- The light source located behind the LCD panel is a combination of fluorescent lamps, reflective and light scattering elements;
4 - film for aligning liquid crystals in a specific direction;
5 layer of liquid crystals;
6- glass substrate - base for installation of electrodes;
7- Color filter designed to form primary RGB colors;
8- gasket for stabilizing the thickness of the LCD layer
Structurally, the LCD display is a multi-layer structure. The principle of action of the matrix is illustrated on the scheme based on the modulation of the light stream from the working lamp due to changes in the transparency of the cells of each elementary pixel (English. Pixel). For the impact on the pixel components in the TFTromatrix, control transistors are used. ADDITIONAL SIGNALS FORWARDED AT THE BLACK OF THE TVERATION BLOCK.
What is mine in clarity?
It is advisable politely, but persistently ask the seller-consultant to demonstrate some television channel. Feel free to reject the arguments about the antenna missing in the store. Suppose the DVD player is the only source. Then it is not bad to grab several licensed DVDs from the house with good familiar movies. For example, a very serious test for your "chosen one" will be a French thriller "Vidok" (director Pitof). This film in cold colors, with an abundance of difficult even for a very good TV, dark scenes can only be viewed on a high-quality display. On the mediocre you just do not discern anything ...
If you manage to turn on the ether channel, you can immediately estimate the level of noise, the quality of the reception. Although much, of course, depends on whether you need LCD TV - to make it 37 inches by the main screen in the apartment or use as a small model for the kitchen, where you will watch news in the morning. To judge the color rendition and other nuances is better in the signal obtained from the ether, but by DVD. At the same time, the picture should not "draw" in red or green. We are stolen in order for quickly moving objects a trace (by the way, a good test page of a football match with green grass and running players). The viewing angle to evaluate is relatively easy. Hospital, often the process of choice depends not only on the consultant's position, but also from the policy of a particular trading point: some manufacturers can be artificially represented in the best or worse light due to manipulations with the image settings. If you approach the selection and subsequent configuration of your TV is very serious, you can purchase special test discs (for example, professional Digital Video Essentials).
RGB (Red, Green, Blue) - Three main colors, combinations of which form all other colors of the visible spectrum in the image on the TV screen.
SCART- The 21-pin audio / video session of European-made, the abbreviation of the French name Syndicat Des Constructeurs Appareits Radio Resepteurs et Televiseurs. SCART has developed a Philips, trying to create a universal switching method of any AV devices.
Composite video signal. The brightness and chroma signals in it are mixed and transmitted by one cable. The corresponding entry of TV is usually implemented on the RCA connector ("Tulip") with a central insert of yellow. A composite compound consider the least high-quality (it is impossible to perfectly restore the components of brightness and chroma). Therefore, the "composite" often manifests defects, especially on large monochromatic sections of the image.
Component video signal. Three so-called colorless signal are transmitted separately. The corresponding entry of the TV is made on three RCA connectors with central inserts of red, blue and green colors. Compound "By Component" is the highest quality of analog methods of video signal transmission. Colorware signals are also denoted by CR (CB), PR (PB), Y. indices.
HDMI (High Definition Multimedia Interface) - Digital interface for transmitting audio and video signals, joint development of companies Sony, Philips, Panasonic, Hitachi. HDMI connection is optimal in terms of video signal transmission, however, the length of such a cable is limited (usually it does not exceed 15m).
Take or not take?
The seller will not be difficult to convince you of the advantage of a specific LCD TV model with a predetermined "test" DVD. Ilishly subsequently, after making a purchase and browsing the houses a regular film or TV show, you will find: with the image something is wrong.
Often you have to hear that a good LCD TV shows no worse and not better than a kinescope, but simply "differently." This "differently" is made up of many factors. Uzhk-displays along with undoubted advantages (excellent image clarity) there are still disadvantages. Ktakov should be attributed, for example, a direct consequence of the layered structure of the matrix - a relatively small screen viewing angle (if you look at the side, the color reproduction is disturbed, the image is pale). However, there is no significant progress made in modern models achieved in modern models in this area.
FireWire 1394 Another disadvantage is associated with inertia (more precisely, viscosity) liquid crystals caused by the so-called matrix response time (8 ms is now considered an excellent value). A results for fast moving objects are drawn by characteristic "plumes". Although it should be noted that similar phenomena are inherent in a kinescope TV. They arise, for example, due to digital image processing.
The color reproduction of LCD displays also leaves much to be desired. Let's say the lack of "depth of black" immediately noticeable when viewed in a darkened room, the details of the black color look befles. However, the ability to customize the image settings in modern models allow you to smooth out a lot.
Even small power consumption is the traditional advantage of LCD TV in front of the kinescopic and plasma- with an increase in the diagonal becomes non-obvious. So, the power consumption is proportional to the size of the LCD display. Ito distinguishes it, for example, from CRT, where consumption depends on the dimensions of the kinescope is significantly less.
WHATS, despite new developments (displays on organic LEDs, SED flat kinescopes), alternatives to the LCD TV as a steadily close-up and attractive image source is not yet visible.
LCD structure
The main element of the modern LCD TV is the so-called active matrix. Twin used miniature TFT transistors that work in key mode, opening and closing the individual cell. The number of cells in the pixel is equal to the number of rgb main colors (red, green, blue). Adjusting the intensity of the glow of each pixel cell, you can change its color as a whole. The matrix is created by cutting from a large billet for several small to install in TV with different screen diagonal. Speaking with the new generation of matrices increases the profitability of their production, from the 7th generation panel (22001870mm), you can make 12 tv with a diagonal of 32 inches. Easily calculate the number of TFT transistors in a matrix with a given resolution. Suppose it is 1366768 pixels. We multiply this number on the number of cells in pixel and we get 1366768 3 = 3 147 264 pcs. For the screen with a resolution of 800,600 pixel, respectively, 1,440,000 transistors. Some manufacturers go to advertising tricks, declaring "permission of 5 million colors", obtained precisely such a non-slip multiplication.
Broken or unborn?
The flow of this company is adhere to different warranty policies. The result depends not only on the quantity, but also on the location of the "broken" pixels. The most unpleasant option is one or several pieces in the center of the display. Some companies use special technologies to reduce their visibility (in particular, the pixel is completely disconnected when one cell fails).
The permissible number of defective pixels (according to IBM)
| Display resolution, pixels | Light pixels | Dark pixels | Total number of defective pixels |
|---|---|---|---|
| 20481536 (QXGA) | fifteen | sixteen | sixteen |
| 16001200 (UXGA) | eleven | sixteen | sixteen |
| 14001050 (SXGA +) | eleven | 13 | sixteen |
| 1024768 (XGA) | eight | eight | nine |
| 800600 (SVGA) | five | five | nine |