Image technology is progressing faster than ever, high definition (FullHD) has now become a standard and the choice of which TV to buy is based on other factors, parameters and prices. As already done for computers, let's see things to know before buying a new TV .
Unfortunately, partly because of the electronics manufacturers' commercial strategies, it is difficult to understand if one technology is better than another.
A TV can cost less but have a sharper image than another which, according to the seller, has superior technology.
The consumer remains very confused in the face of these indications that would seem to contradict what is seen by eye.
This simplified guide can be a basis for choosing and purchasing, perhaps to take with you when you go to the shopping center, to deal on equal terms with the shop assistant / seller.
First of all let's see what are the most important terms related to HD TV, to know the meaning.
- Contrast ratio : difference between white and bright colors with darker colors and black; The higher the ratio, the better the contrast.
- Refresh rate : How many times the screen redraws the created image.
The refresh rate is measured in hertz or cycles per second.
The higher the refresh rate, the better the quality of the moving images, with reduced blur and greater clarity.
Plasma screens usually have a much higher refresh rate, with 600Hz refresh rates, but LCD and LED TVs are recovering ground with values ranging between 60, 120, 240, or even 480Hz.
- Pixel response time : similar to the refresh rate, the pixel response time is the number of milliseconds with which the individual pixels react to the change of image.
Response time refers to how quickly individual pixels change color from white to black, red or green.
The lower the time, the better and the fast moving images will be less blurry.
- Resolution : All FullHD TVs have the same resolution of 1920 × 1080 at 16/9; if you want to spend less you can still find and buy an HD Ready TV with a lower resolution and, therefore, a less clear image (although the broadcasts of the normal Rai and Mediaset channels are not HD).
The best-selling TV models in shopping malls are roughly of three types
1) LCD : An acronym for Liquid Crystal Display (liquid crystals), it is the most common screen model and is present on televisions, computer monitors, laptops, some watches, cell phones and microwave ovens.
LCD screens were the first type of thin monitor, with good image quality.
Until recently, LCD TVs showed lower image quality than CRT (old cathode ray tube TVs), with less color depth and lower contrast ratios; today, on the other hand, they have improved significantly and can be seen well even in well-lit rooms.
Liquid crystals do not emit any light and must be backlit.
When an HDTV is classified as an LCD TV, it means that it is backlit with CCFLs, i.e. cold cathode fluorescent lamps.
To find out more, refer to the page on flat panel LCD monitors
2) LED : Acronym for Light Emitting Diode, it is the same as an LCD, with a different type of backlight (Light Emitting Diodes).
LED TVs are widely advertised in the market and sold at higher prices but they are not exactly the revolutionary innovation that they want us to believe.
They offer some advantages over LCD-HD, including: lower energy consumption, absence of mercury and therefore greater eco-sustainability, higher contrast with a blacker black, a wider range of colors and better aesthetics with screens thinner.
Conversely, the price is much higher and, if I can afford it, in an unjustified way.
There are two types of LEDs : Full Led with truer blacks and a higher dynamic contrast ratio; Edge-LED TVs are ultra-thin screens with uniform color distribution that are also cheaper.
The LEDs still do not reach the contrast ratios obtainable with Plasma televisions but offer a much better image quality than an LCD.
3) Plasma
Plasma screen TVs have the best image quality that can be found on the market because they have a high contrast ratio and a wide range of colors available.
Plasma is used only for very large screens and they are also available in 50 "versions at not exorbitant prices.
Plasmas are also thin and can be hung on walls like LCD or LED televisions.
The response time of the pixels is considerably longer than the LEDs and the LCDs so the images that move quickly (like a football or tennis match) are better seen.
Plasma televisions also have a wider viewing angle of images so you can see well even if you put yourself sideways and become better than the others when watching TV in a group.
Although plasma TVs are better screens, they have the big downside of consuming a lot of energy compared to other technologies.
They are also not very sustainable due to the presence of harmful chemicals inside and the disposal of a plasma TV is more expensive.
Plasma is also more vulnerable, less durable and easier to break than LCD / LED screens.
For these reasons, there are fewer and fewer plasma TV models on the market.
Other types of TV are:
4) Rear projection televisions (RPTVs)
This type of TV is no longer found in shopping malls and today only serves for specific needs.
It is an evolution of the CRT with cathode tube, with a much thinner thickness and a clearly lower weight (inside they are almost empty).
Rear projection televisions are recommended for those who need a very large screen, even 82 "(such a large LCD would cost a lot).
The biggest problem, from what I have seen, is that they work with a lamp (like normal projectors) which, if it breaks, must be replaced at a minimum cost of 200 Euros.
5) 3D televisions
Taking advantage of the trend of 3D movies, many high definition televisions have support for watching 3D movies.
The main problems of 3D-TV are the scarce (not to mention total absence) offer of 3D TV programs and the need to use specific glasses depending on the model.
In another article: Difference between 3D TV models, active and passive with or without glasses
6) Smart TVs or smart TVs with internet connection, of which I speak in another recent article.
When buying a TV, you also need to make sure it has all the sockets for connecting external devices.
In another article I had explained the various types of most common connector sockets and cables.
The USB port for connecting external hard drives or sticks must not be missing in a new TV.
The network socket for connecting the TV to the Internet can also be important, although for now we cannot hope to surf the web fluently from television.
Unfortunately, the various models of TV-HD also differ according to the software they use inside them.
The important thing is to check that the TV can play Divx videos (for example read from the USB stick).
In conclusion, it cannot be said whether one type of TV is better or worse.
Understanding which TV to buy depends very much on the specific needs and use of the TV .
For example, if you watch football matches and sports, a TV screen with high response speed (Plasma) will be preferred; if you watch TV a little, maybe you would prefer it to be a nice piece of furniture (LED); If you often see films in Blueray, it takes a high contrast ratio (LED); if you use the TV only to watch the RAI or Canale 5, it is useless to spend a lot of money, you just need a medium level LCD; video game players may prefer to see the hotfix and bright colors of LEDs or Plasma; in some circumstances, if you need a very large TV screen, you could opt for a rear-projection television.
I just have to ask, from your comments, more information (more than technical practices) useful for the purchase of a new TV.
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