Basics of TV explained
There are basically four different kinds of wide flat screen TVs available in India today. These are LCD TV, LED TV, Plasma TV and OLED TV (OLED= Organic Light Emitting Diode) TV. There are the old Cathode Ray Tube TVs, but they are almost discontinued now and so we will not discuss about these old types TVs. We will concentrate on the newest flat screen TVs below.
Among the basic types of flat screen TV, there is a distinction between TVs based on the TV screen resolution or how many pixels there are on the screen. So we have HD ready TV, Full HD TV and 4k Ultra HD TV. Then the flat screen TVs are further subdivided according to its features like 3D TV, Smart TV and the newest Curved TV. For a full and detailed explanation about all TV types and all TV specifications and features, visit our website www.WhatTVs.com.
Here we will discuss about the basic TV specifications like TV size, TV picture resolution, and a few other important aspects about TV sets.
What is the difference between HD and 4K TV
To understand what are HD and 4K TVs we must first know what is TV screen resolution. HD (high definition) and 4K refers to the resolution of a TV screen. The following picture can best explain the meaning of TV screen resolution. The picture below compares the difference between a low resolution (left) and a higher resolution TV picture (right). Obviously the higher resolution picture has much more clarity and is a pleasure to watch. We will now explain all the meanings of terms like pixels, TV resolution and other factors which make a TV HD or 4K.
The picture on a TV screen is formed by millions of small square picture elements. If you look close up at a TV screen you can see these small square, mosquito net like pattern. Each square is a picture element with the shortened name “Pixel”.
The more the number of pixels in a TV screen of same size, the higher the TV screen resolution. The images above compare the pixels in an ordinary TV (left) and an HD TV (right). With the pixels packed closer together, there are much more pixels in the same area of a 4K TV than an HD TV and this means a much higher resolution picture. The closer the pixels are together the clearer the picture gets. For example an HD TV has 4 times more pixels than an ordinary TV and a 4K Ultra HD TV has 4 times the number of pixels there is in a full HD TV. Hence a 4K TV will look much sharper especially close-up.
The image here represents the mosqito net like pixel arrangement on the screen of a TV. The same letter ‘A’ looks distorted on the left due to wider pixels owing to fewer pixels than on the same letter ‘A” on the right which has more pixels and the pixel net pattern is packed closer together. Thus the more pixels there are on the TV screen the better the picture will look.
The area the letter ‘A’ occupies in both the pictures is the same, thus when there are more pixels in the same area, the letter ‘A’ is much clearer. Same thing applies to a TV screen. A TV of the same size screen having more pixels will be much clearer and is called a TV with a higher resolution. Resolution is therefore the number of pixels in a fixed area. Theoretically therefore Resolution can be called the Pixel Density on a TV screen.
In practice all HD TV screens have 1920 pixels horizontally in the ‘x’ direction and 1080 pixels vertically in the ‘y’ direction. This is usually written as 1920×1080 pixels. For a 4 K Ultra HD TV screen the pixels are packed 3840 horizontally and 2160 pixels vertically or 3840×2160 pixels. The ‘K’ in the 4K stands for ‘Kilo” which is a thousand. Thus 4K means 4,000 and in the 4K UHD it signifies the 3840 horizontal pixels which is nearly 4000.
TV screen size meaning explained
TV screen size is the most important TV spec that matters most. How is TV screen size measured is explained as follows. The size of a TV is the measurement of the TV screen size diagonally from top corner to bottom corner on the other side- for example from top right corner to bottom left corner, in inches in USA and UK and in centimeters or cms in most other countries. Only the visible screen area is measured when measuring the size of a TV, the side frames are excluded.
The picture above shows how a TV is measured, the green coloured measurement is wrong and the red colored measurement is correct. The dimension in the red colour showing the TV screen size of only the screen and excluding the frame is the correct screen size, in this case the TV screen size is 46 inch and not 51 inches shown in green. Since one inch is equal to 2.54cms (centimeters), the Metric TV size of this 46 inch TV will be 116.84 centimeters. The decimal points are usually rounded off and thus the 46 inch TV in India will be a 117 cms TV.
How far to sit from the TV
When watching TV a common question is “how far to sit from the TV”? It depends of the TV size on how far to sit from the TV when seeing TV. The resolution of the TV also plays an important role on how close you can sit from a TV to watch TV. High Definition TV and 4K ultra HD TV allows you to sit much closer than to a Standard definition TV. This is because the pixels in 4K Ultra HD TV and HDTV are packed so close together that you cannot see the pixel net like structure in the TV picture even sitting close up to the TV.
As a general rule the HDTV viewing distance is a minimum of 1.5 times the screen’s diagonal measurement, but for regular viewing it is better to sit a bit further. Thus the optimal best viewing distance for 60 inch HD TV will be at least 90 inches or 7.5 to 8 feet (about 2.3 meters) from the TV screen.
There are no official bodies, as yet, to recommend viewing distance for TV size. Various TV magazines and TV testing bodies recommend various Television Screen Size to Viewing distance. From a selection of these recommendations, we have made a TV Size Viewing Distance table below. It only gives you a rough idea of the recommended viewing distances. The maximum distances are flexible, but the minimum distance mentioned in the table below, is the minimum obtained from several sources, so that should be followed.
|HDTV screen Size||Minimum Distance||Maximum Distance|
|32″||4 feet||13.5 feet|
|37″||4.6 feet||15.3 feet|
|40″||5 feet||16.3 feet|
|42″||5.25 feet||17 feet|
|46″||6.75 feet||18.3 feet|
|52″||6.5 feet||21.3 feet|
Further knowledge about TV sets
We have summarised only some of the important points regarding TV sets here. We have a dedicated website explaining all about TV sets and we invite you to please go through that website for more knowledge about TVs. This is the link to our website www.WhatTVs.com
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