The abbreviation “LCD” stands for “Liquid Crystal Display”, which means, of course, “liquid crystal display”. Well, “TFT” is “Thin Film Transistor”, that is, “thin film transistor” (since “film” is also “film”). However, the subtleties of translating names are unlikely to interest you. You, presumably, just want to get an idea of the essence of such devices, which have become, without exaggeration, an everyday part of electronic and digital life.
What it is
LCD TFT differs from the usual, primitive liquid crystal display found, for example, in a simple calculator by the use of an active matrix, which operates under the control of thin-film transistors.
These are arranged in microscopic rows on a special glass substrate installed under the cells with liquid crystals.
In short, depending on the control signal, the crystals line up in front of the color filters (red, blue and green) to allow light to pass through them differently. In this way, different colors are formed, combining into a complete image according to the principle of a mosaic of pixels. Of course, all this would be too dim without additional lighting, and it is certainly involved.
Let's look at the operation of a thin-film transistor in a little more detail. He has the following conclusions: 1) shutter; 2) source; 3) drain. The control voltage from the so-called scan line (on electrical diagrams connected to a common bus) is fed to the gate. As soon as it arrives, a signal is sent from the drain to the cell, forming the desired potential difference.
If nothing enters the TFT gate, then the cell with liquid crystal molecules is inactive.
Advantages and disadvantages
The advantages of LCD TFT are quite obvious, literally. Brightness, clarity, contrast, relatively low power consumption even for large monitors (this is not a cathode ray tube!), compactness (can be installed in phones, cameras), health safety (no radiation, like from all kinds of picture tubes). Progress in all its glory.
By the way, about health. There is no flicker like cathode ray tubes. Therefore, the eyes do not get tired even at a refresh rate of 60 hertz.
There are also disadvantages. While current technologies can more or less cope with color rendition, brightness and contrast, the viewing angle is often not particularly wide, especially in terms of adequate color rendition.
In addition, crystals are not always liquid. In the winter cold, imagine, they tend to freeze. Therefore, it is advisable to carry smartphones-communicators in internal pockets, under outerwear.
And transistors, even microscopic ones, can simply fail. Then so-called dead pixels appear - dots that are unable to change color. When buying any device, be sure to look at the entire screen area with a meticulous eye.
If a small display contains, say, 1366 pixels in width and 768 in height, then it is better to leave it that way in the settings. Need more resolution? Then buy a bigger, more impressive monitor.
In other words, best option- use of “native” resolution.
What to choose
The oldest and cheapest technology is Twisted Nematic (“TN”, expanded to “TN+Film”). The products are inexpensive, but of depressing quality.
For home and office work, TFT IPS displays created by Hitachi and NEC are better suited. They are a little less fast, but this is not critical.
There are also modified versions of “TFT H-IPS” (“Horizontal IPS”), “TFT U-IPS” (“Ultra Horizontal IPS”) and other fruits of engineering.
But the best are considered to be “Professional IPS” displays (respectively, “P-IPS”) with very deep color rendition. Especially for professional photographers, artists, designers, printers, and so on. However, prices for “TFT P-IPS” are extremely steep.
Conclusion
Cathode ray tubes, which irradiate the computerized population, have a bad effect on vision and are extremely harmful primarily to children, fortunately, have almost died out (except for some budget organizations that save on office equipment). In general, that’s where they go. Since passive matrix LCDs do not meet modern requirements, the world will not survive without further development of TFT technology. So follow the news and choose a quality product.
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And again there is a confusion of concepts. If you are trying to determine the difference between monitors or televisions that someone called TFT and LCD, then you have been misled. Try to find the differences between a bus and Ikarus? Between the dog and the neighbor's Bug? Between fruit and apple? That's right, the exercise is useless, because both objects are both at the same time. So it is with screen matrix technologies: LCD is the general name for a class of displays, which includes TFT.
Definition
TFT matrix- active matrix LCD display, made using thin-film transistors.
LCD- a flat display (and a device based on it) based on liquid crystals.
Comparison
LCD displays are not an invention of our century. The screens of electronic watches, calculators, devices, players are also liquid crystal, although they differ significantly from the screens of smartphones or TVs that we are used to. True, at first LCDs were monochrome, but with the development of technology they blossomed in the RGB range. TFT is also a type of LCD display, the production of which is based on an active matrix based on thin-film transistors. If you compare it with the earlier version of LCD, the passive matrix, it becomes obvious that the color quality and response time of TFT is much higher. Twisted polymer is used as crystals in passive matrices. But the energy consumption and cost of passive matrices, called STN, can please anyone. However, monochrome screens in this regard will generally look like prizes, but there are unlikely to be many people willing to watch such TVs.
Principle TFT work is that each of the thin-film transistors controls a single pixel. For each pixel there are three transistors corresponding to the primary RGB colors (red, green and blue). The intensity of the light flux depends on the polarization, polarization depends on the application of an electric field to the liquid crystals. TFT involves increasing the level of speed, contrast and clarity of the resulting image.
It is worth noting the disadvantages TFT matrices, eliminated in other technologies. The image quality directly depends on the external lighting of the screen. Transistors at any of the pixels may fail, which leads to the appearance of “dead spots”, or dead pixels. No screen can be protected from this. In addition, TFT matrices are largely energy-intensive, so their use as displays for mobile electronics forces one to sacrifice one of the most important properties - autonomy.
Thin-film transistors, which formed the basis for the operation of liquid crystal matrices, today have practically fled to a different camp: OLED screens use them to control their active matrices. There are no longer liquid crystals here, but organic compounds.
Conclusions website
- LCD is a type of screen matrix based on liquid crystals.
- TFT is a type of active LCD matrix.
- TFT makes it different from others LCD technologies use of thin film transistors.
- TFT matrices are economical, provide high-quality images, but are energy-intensive.
Liquid crystal displays have almost replaced earlier CRT monitors from the market. This is due to the significant advantages offered by the new TFT screen.
Advantages of TFT technologies
One of the main advantages is the absence of geometric distortions, which CRT screen developers have struggled with for a long time, but almost unsuccessfully. Any TFT screen or monitor has a flat rectangular shape, which eliminates distortion both in the corners and in the center.
No less significant is the absence of flicker, which the human eye cannot detect at frequencies above 85 Hz, but it is present, creating significant strain on the eyes. The TFT screen does not flicker. When the image changes, the illumination changes (by changing the direction
TFT screen technology has significantly reduced the level of electromagnetic radiation. The effect of this type of radiation on the human body has not yet been fully studied, but all scientists agree that it is clearly not so useful. 
Because the lower electromagnetic radiation, all the better. And the TFT screen has a much lower level than previously used technologies. This feature allows them to use TFT monitors and screens in medical institutions and in industries where induced interference can negatively affect various processes and the operation of other equipment.
Another plus is the small size and light weight that distinguishes the TFT screen. Such a monitor can be hung on the wall, then it will not take up space at all. This is especially true in confined spaces or where dozens of such devices accumulate. The positive properties include low energy consumption and insignificant heat generation during operation. 
This is again significant when there are large concentrations of monitors in one room. A small heat release allows you to save on the organization of ventilation and energy costs for its operation, reduced electricity consumption allows you to save on electricity bills (TFT screen consumes 3-4 times less electricity than its predecessor CRT).
Screens using TFT technology are more reliable than their CRT counterparts, which use high voltages to operate, which often leads to breakdowns. Liquid crystal technologies use low currents, which increases their reliability.
Disadvantages of TFT technologies
TFT transistors also have some disadvantages, and the main one is their high price. But savings on electricity, low thermal radiation and high reliability (as a result - no repair costs) quickly pay for the additional amount that you have to shell out when purchasing.
The next disadvantage is restrictions on ambient temperature. But this applies more to industrial use TFT screens: they cannot be used in hot workshops and at subzero temperatures, which, you see, is unimportant for home use.
The disadvantages include the presence of “dead” pixels that appear sooner or later. This is, of course, unpleasant, but not fatal. If out of several thousand points a few fail (this is how everything is calculated), then they will either not interfere with you at all, or will be very small.