How to choose TV

How to choose TV

Vania Technic / 
07-03-2019 / 
Video  / 

For the modern man, the TV is a window into the world, and a source of all kinds of information, and a way to have fun. Over the past two decades, television has become a complex, multi-functional device. To cope with the settings which without the advice of a specialist is not always possible even for certified engineers. Not to mention the right choice, among similar devices, uninitiated in modern technologies.

In this article we will get acquainted with the important today functions and technical parameters of modern TVs - to certainly understand what is right for you and how to make a really right choice among this huge range.

How to choose the size, resolution and format of the TV screen

Resolution screen quality

The diagonal size is perhaps the most well-known parameter of television receivers. The choice of options today is extremely wide. The most popular model with a screen size of 32-37 inches, as a large diagonal is often perceived by the consumer as an excess.

Experts recommend, to effectively view the video in Full HD resolution, to choose the diagonal of the display to the ratio of the distance from the viewing point by multiplying the possible diagonal by three. For example, 32x3=96, in this case the number 96 is the optimal length of the distance in centimeters to the viewing point for a 32-inch display.

It is useful to remember the recommendations of doctors. In their opinion, the optimal diagonal length should be 3-5 times less than the viewing distance. With smaller screen sizes You will have to strain your eyesight, and with too large - the eyes will get tired because of the need to cover the full picture with too wide viewing angle.

But still for the most effective viewing of movies, regardless of the ratio of diagonal and viewing distance, avid moviegoers prefer for 2D-image diagonal of at least 42 inches, and for spectacular viewing of 3D-images from 50 inches.

The display resolution affects the clarity of the image (Pic.). The resolution is determined by the number of pixels per inch used to create the image. In small diagonal displays resolution usually does not exceed 1024x768 pixels, with increasing diagonal size, should grow and resolution. Otherwise, the picture will be grainy. In models with a diagonal of more than 27 inches resolution should be at least - 1920x1080 pixels.

Please note, the description of the TV the resolution specifies the number of rows, for example 720p, 1080p, 1080?. Latin letters determine the type of scan: "I" - interlaced, "p" - progressive. Or, the display resolution is indicated as HD and Full HD.

Although there are almost no high-resolution (HDTV) programs in the terrestrial broadcasting grid, some satellite channels and cable TV programs are already broadcast in HDTV resolution. On the shelves you can also find DVD and Blu-Ray players that can play videos in high resolution.

Since 2012, models capable of working in the Ultra HD standard have appeared on the market. This abbreviation has become, perhaps, one of the most noticeable trends of today. The main argument of supporters of the new image quality 4K/Ultra HD - "fourfold superiority over Full HD". If you look at the numbers, this statement seems to be true. Let's compare.

Ultra HD

  • Resolution: 3840x2160 or 7680x4320;
  • Color depth: 10/12-bit;
  • Scan: 50-100 frames per second, progressive;
  • Color coverage: 75.8%.

Full HD

  • Resolution: 1280x720 HD or 1920x1080 for full HD;
  • Color depth: 8-bit;
  • Scan: 50 frames per second, progressive;
  • Color coverage: 35.9%.

The indicators are really impressive. And it's not just the number of pixels in the TV frame, the standard Ultra HD implies a noticeable improvement in signal quality. As can be seen from the table, this video will contain much more information about the color of the picture than capable of playing modern HD and even Full HD TVs.

But here, as in HDTV, the main problem is the lack of content today. Today there are no videos, no movies, no TV shows created in 4K/UHD format. So hurry with the purchase is not worth it. By the time sufficient volumes of UHD video materials are created, the cost of models of this standard will be significantly reduced.

The aspect ratio of modern screens can vary in height and width, that is, format. Until recently, the standard 4:3 was adopted, today such devices are practically not available, they were replaced by models 16:9. In this format, DVD and Blu-Ray discs are recorded today, broadcasters switch to large-format broadcasting. A few years ago on sale there were TVs of even wider format 21: 9. The advantages of this solution were immediately appreciated by film fans, as wide-format films can now be watched without annoying black fields framing the frame from above and below. This screen effectively uses every inch of its area, demonstrating the excellent quality of HD video playback.

Types of matrices of modern TVs and their parameters

Display TN VS IPS

Having determined the size and resolution of the screen, think about what technology it should be made. Today, modern TVs use several types of displays: plasma, liquid crystal, projection and OLED. Two of the latter we will not consider because of the unpopularity of this type.

The LCD screen can be made extremely thin, while it will create a picture of exceptionally high quality. Such a TV does not require large amounts of electricity for its operation. The television image on the LCD display does not flicker to the beat with changing the frame of the television signal (25 or 50 times per second), as it happens with other types of monitors. LEDs on the screen are arranged with a certain step, they observed the effect of darkening, which manifests the unevenness of the screen. Some areas of the image acquire a different grayscale than the original signal. This problem is solved by the use of LED-backlight.

In modern LCD matrices, three main types of LED backlight are used. The most expensive and complex technology in production RGB LED, allows to achieve a wide color gamut and high accuracy of colors. Technology Full LED, gives some advantages, it allows you to best implement local dimming on the screen, with part of the backlight is turned off, and the contrast increases. Backlight on the edges of the screen, or EDGE technology, allows you to make the TV very thin and today it is the most commonly used type of backlight.

Liquid crystal matrices are also of various types. Of these, the most commonly used are IPS, S-PVA, UV2A and legacy technology TN. TVs LG, Philips, Panasonic and some other brands are often equipped with IPS matrix, they provide good viewing angles, but have a fairly long pixel response time and not quite deep black. Samsung prefers the matrix S-PVA, which provides a deep black color. Matrix S-PVA, can also be found in models Panasonic or Philips. ONE of the most advanced types is the UV2A matrix, which has an acceptable response time and good viewing angles. Such matrices set only in top-end series models like Panasonic or Philips. As for the low - end models, they are equipped with old-type matrices-TN, which are significantly inferior in image quality and viewing angles, but exceed the speed of the pixel response of other types of matrices.

Plasma panels (PDP - plasma display panel) have a number of advantages. In particular, high contrast, natural color and very low latency pixel response. The panel will be flat and thin enough without any restrictions on viewing angles. Unlike kinescopes, in plasma panels all problems of convergence of rays, focusing and linearity are solved. Plasma is also not peculiar to the manifestation of flicker or harmful radiation. Plasma panels are no types of matrices as LCD, but has its own generation. The most perfect for today is the 15th generation.

Display 16-bit VS 8-bit

The color depth or bit depth of the matrix indicates how many different brightness gradations the matrix cell (Pic) displays. The bit width is specified in bits. Usually all types of matrices are 8-bit, which reproduce 256 gradations of each color, which corresponds to the limit of vision 256x256x256 = 16777216 colors. Don't be surprised to see plasma screens with 10, 14 or more bits. This seeming excess allows to take into account some technological defects of color reproduction of modern displays. On sale can be found and low-end devices with matrices 6-bit plus 2-bit emulation (6bit+A-FRC), so the manufacturer reduces the cost of the product that affects the level of color reproduction and display gradients. In any case, given the numbers in the registration certificate, rely on your perception.

Pixel response time is also important to consider when choosing an LCD TV. For the qualitative formation of a color moving picture, the state of liquid crystals should change quickly enough. The time interval during which the position of the liquid crystals is changed is called the response time. In the case when the response time is unacceptably long, when displaying scenes with dynamic movement, there will be plumes stretching behind fast moving objects, as well as horizontal and vertical pixel twitching, noticeable both in 2D and in 3D. To obtain a high-quality image, the response time should not exceed 8ms. Only with this value, viewing dynamic scenes will be comfortable enough. As for plasma screens, this parameter is not relevant for them, since they have a pixel response time usually about 0.5-0.6ms.

Input Lag (input delay) is also an important parameter. Input Lag is caused by the difference between the time a new frame is received from the video card output to the display input and the moment when this frame starts to be displayed on the screen. Each new frame coming from the video card output is written to the buffer before it comes to the screen. The result of a significant delay in the input (too high input lag) may be a noticeable lag of the television image from its sound or twitching pictures on dynamic scenes. This defect can be in both 2D and 3D images. To comfortably watch a dynamic scene, the increased Input-Lag should be less than 100ms. To properly synchronize the 3D image, the matrix uses fast electronics that can give less than 10ms.

Frame rate per second is an important indicator of image quality. According to doctors, when the number of frames per second exceeds 24 (standard filming), the human eye perceives their sequence as a moving picture. On sale you can find models with a frame rate of 60, 120, 240, 480 or more Hz, that is, the frames change much faster than necessary. This helps to reduce eyestrain, improve the quality of dynamic scenes and reduce pixel twitching, which makes the picture smoother. For 3D images, a frame rate of at least 120Hz is mandatory.

One of the important parameters that companies such as SHARP and SONY are constantly working to improve the anti-glare display coatings. After all, the quality of the image is affected not only by the type of matrix but also its external coating. On sale you can find three types of coverage – glossy, matte or glass with anti-reflective filter. The first is characterized by good values of clarity and contrast. The main drawback is its strong glare, visible even in a poorly lit room. Screen with a matte finish has almost the opposite characteristics. It does not glare, but has a lower contrast and distorted original image because of its structure, thus there is a wet rag effect. The latter, the best option, is usually used only on plasma panels.

Additional Plasma or LCD TV options

Additional option for TV

All modern TVs are equipped with analog or digital (DTV) terrestrial TV tuners. Choosing a new TV, pay attention to the compatibility of broadcasting in your country by the following parameters - DVB and MPEG compression.

When choosing a new TV, it is also necessary to consider the possibility of connecting certain multimedia devices to its input. The vast majority of modern models provides for the presence of standard interfaces – analog: S-Video, SCART, composite or component connectors. These and are satellite receivers, Blu-Ray players, and digital HD cameras. Such devices mainly use the interface: DVI (Digital Visual Interface), DP (DisplayPort) and the most commonly used - HDMI (High Definition Multimedia Interface). Make sure that the TV you have chosen has the required number of connectors to connect possible devices and pay attention to their version.

It is also desirable to have a USB-connector or a card reader that allows you to play any files from digital media: photos and videos, music files and presentation slides. Or maybe you do need a built-in DVD or Blu-Ray player-which is especially important for a TV in the bedroom or in the kitchen.

If the TV is compatible with the DLNA standard, it is quite capable of becoming a full component of the local network, along with computers and laptops. In this situation, any multimedia content from your computer will play on its screen without any problems. And it's even easier if the TV is equipped with a Wi-Fi adapter. Usually the TV is connected to the Internet is the reason for the existence of the functions of the Smart TV (Pic).

In conclusion about choosing a plasma or LCD TV

When purchasing a new TV, check all the described parameters, their values can be found in their passports and technical description of the model. But what is extremely difficult to determine at the time of purchase is the presence of "broken" or defective pixels on the monitor. "On the eye "to do this is almost impossible, especially in a store where the seller seeks to show the" product face", displaying on its screen bright multi-color videos that should show the buyer the quality of color and saturation of the picture. On such a screen it is very easy to hide the presence of damaged pixels. They can be seen only on plain backgrounds. At the same time, the background color is not important, because, for example, on a green background, a broken pixel will appear as a red dot.

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