TV is selected based on several criteria. First in the list are the size and the screen resolution of the visual factor is considered the most important. Happens, buying a TV, the user detects the absence of important functions. As a result, use of equipment becomes difficult. Today, let's see how to select the TV to the purchase did not disappoint.
On the shelves dominated by two basic families screen matrices:
- The liquid crystal matrix uses the properties of the crystals to change the degree of polarization as a function of applied voltage. Due to this metered quantity of light passing through the active layer. On the described principle is based manufacturing of LCD TVs. The traditional disadvantages of this type of product has a lot of inertia. The phenomenon is characterized by the response time of the screen. We believe meaningless to give specific values. Experts argue for comfortable viewing is enough to buy a TV with a 20-25 ms response time.
TV on the wall
- The disadvantage of plasma televisions has long been considered the complexity of the manufacture of the array. In the course of development of the assembly line was a large percentage of marriage for these types of TVs. Today, the lack removed, the advantages of plasma panels is easy to test in practice. This is an excellent response time, high contrast ratio. The disadvantages of plasma TVs carry a relatively large pixel size. In fact, the pixel is a tiny bit light bulb. Therefore it is difficult to find a plasma TV with support for full hd with a diagonal of at least 40 inches. This is done for a simple reason: the above-mentioned light bulbs do not fit in a smaller area. Know at close range plasma TVs do not look. Otherwise, all pixels become visible. At this disadvantages over.
Ask how to choose the right distance to the TV. Some experts typical result of formula which states that the acceptable range is from three to five screen diagonals. This does not correspond to reality. Often on a computer monitor, we are much closer without noticing the grain.
The strength of a man, and the distance to the screen
Distance to the screen depends on the resolution of the matrix and the strength of view. As the distance is related to the size of a pixel? The human eye can distinguish some angular distance. This is called the resolution of view. With the permission of the site is made nplit.ru excerpt of information materials cited therein. Astronomers say:
A sufficient distance from the TV
- The Big Dipper has two stars. Mizar and Alcor. The angular distance between the luminaries is 12 degrees. Little star next to a large can distinguish virtually anyone.
- In the constellation of Capricorn, two close stars. The angular distance is 6 m. The man with the power of 1 is quite able to distinguish between the stars.
- The man, seeing that Epsilon Lyrae - a double star, has a very sharp vision. The angular distance is only three minutes.
For each visual acuity - the proper distance from the screen. For example, in the store came a man whose medical book worth edinichka. Firstly, the need to try to estimate the distance to the right eye. We believe that distance to be calculated, which upon removal of the pixel size does not exceed 4 minutes. This angular distance from the margin. Let's say the screen size is 40 inches, resolution full hd.
The size of the matrix is 1920 x 1080, and the aspect ratio of 16 to 9. Find screen sizes. diagonal length in shares will be 18.35. One share is equal to 2.179 inches. So, the width is 34.86 inches - 88.55 cm. It is 1920 pixels. By 0.46 mm each. With a distance of said length will appear angular distance of 4 degrees?
It is important to adhere to a safe distance from the TV
The answer is of a right triangle. Sine of half the angle is equal to the resolution of half a pixel width divided by the distance to the screen. Hence it is easy to find the desired value of X = 0.00046 / 2 sin (0,0 (3)). So, the initial visual acuity distance in meters is approximately equal to the pixel width in millimeters, accounting for 0.46 m. In practice, in the conclusions is easy to see if you take the typewritten text. From a distance of 46 cm easily discernible gaps between adjacent characters 0.5 mm wide. But it is necessary to move away to a distance twice, the difference disappears. Consider your own eyes:
- Calculate the size of the screen pixel by the formula given above.
- Search on the typescript of land, about equal in length.
- To determine the distance from which the difference is imperceptible.
- It takes a minimum distance from the screen.
The described technique is not worse than accurate calculations related to astronomy, makes it possible to estimate the size of the parameter. The method is optimal because it takes into account the individual parameters. To find out the pixel size does not need to leave the house. The parameters of most TV models listed on the internet. This takes into account the aspect ratio, diagonal size and resolution. Are the length and height of pixels (rectangular).
The screen resolution and the distance to the TV
For large families or social institutions is necessary to select the TV, on the basis of authorization. The higher it is, the distance to the screen is less. In order to achieve the result is possible to apply the method described above. Diagonally, resolution and aspect ratio to find the pixel dimensions, then experimentally or formula to calculate the distance. Ensure that the result does not coincide with the typical recommendations. Distance from three to five diagonals given for television cathode ray tube. Opt for physicians, for reasons of security for the view, the picture quality is not taken into account.
Draw a small number of logical conclusions. Usually the room size in length does not exceed 5 meters. Diagonal old TV could be 70 cm. Given that cell phones and sofa physically impossible to put on a distance of 5 meters, we obtain the formula given in. It refers not to the resolution of the TV and the picture quality, and safety. Any monitor emits harmful radiation, but it is difficult to compare the risk of electron beam gun. Today of televisions element removed, when determining the distance to the screen originate from other considerations.
Thus, the distance to the TV is dependent on three factors:
- The strength of the audience.
- Screen resolution.
- Geometrical dimensions: diagonal aspect ratio.
On the Internet you can not find a single recommendation for the installation of the selected TV. But perhaps get a table resembling ophthalmologist table on which to evaluate the proposed option.
Set the TV interface and operating system capabilities
A lot of TV is equipped with android operating system. Key features and specifications of the device are converted into ordinary gadget: a cell phone, ipad. It becomes convenient to interact with the TV. Any student knows how to deal with your smartphone. TV manufacturers are interested in and offer to buy the consumer goods with android operating system. Becomes available playmarket catalog, hundreds and thousands of useful applications.
Customers will be able to put skype or vayber, use a new acquisition in the manner of a mobile device. Do not confuse the absence of a SIM card (to Favorites TVs may insert), special methods is resolved. Choosing a TV, make sure that the equipment supports the necessary interfaces. For example, to play blu-ray disc is required hdmi port of the second generation. The number of inputs and outputs is consistent with the sum available in the home devices: top box, personal computers, video players, and more. It is better if the switching is performed once for the entire remaining period of operation. Under each device needs its own input and output.
A simple technique will allow to estimate the parameters and to resolve the situation with the choice of the TV.