At the time of monitors and televisions created on the basis of a CRT (cathode ray tube), each person should at least have a general idea of ​​what the screen refresh rate is. Unless, of course, it was important for him to preserve
vision, do not experience headache and associated discomfort when working at a computer or watching TV programs. We can say that the refresh rate of the screen was indirectly related to health. In our time, the situation has radically changed. Graphic information display devices were created using completely different operating principles than CRT technology. Although the LCD screen in TVs and monitors is not yet so perfect as to speak of complete harmlessness: the effect on vision has decreased significantly, but has not completely disappeared.
The answer to the question of what is the screen refresh rate is easiest for owners of computer monitors. If you use the latest Windows operating system, you need to call up the menu in any free place on the desktop by pressing the right mouse button and select “Screen resolution” in the list that appears. Next, proceed to the "Advanced Options". Here by opening the tab
“Monitor”, you can see the line “Display update rate”.
In modern monitors based on liquid crystals, 59 and 60 Hertz are usually available - this is for budget models; in more expensive, you can also set 75 and 100 Hz. LCD screen refresh rate is a legacy of the CRT era. In liquid crystal models “by eye” it is impossible to distinguish between 60 and 100 Hz. The only thing this parameter is affecting now is the smooth movement of the mouse cursor and the ability to use 3D glasses (100 Hz are needed just for them).
But in the days of CRT, everything was different. The inner surface of the screen (tube) was covered with a layer of a special substance (phosphor), capable of glowing for several milliseconds after electrons hit it. Three electrodes (guns) emitted particle fluxes by emission, the movement of which was corrected by a magnetic field. It deflected the rays from a straight line, so that the upper left corner of the screen began to glow, then the stream caused a glow along the horizontal line to
top right corner. Then the beam was shifted one line down and everything was repeated. When reaching the lower right corner, he returned to the beginning and everything was repeated. The number of such screens drawn per second represents the refresh rate.
In the LCD controller it is capable of selectively changing the passage of light through the elements of the matrix of liquid crystals - you can simultaneously light up or turn off the screen. The flickering of the backlight itself is the last drawback that is being actively eliminated in new models of monitors. The phosphor on the screen still glowed, creating the illusion of a holistic image. The eye simply did not have time to notice the flicker caused by the constant updating of the picture. However, it was present, and at refresh rates less than 75 Hz it was noticeable by side vision. To eliminate this effect, manufacturers offered monitors with frequencies even above 120 Hz. Of course, the described scheme is simplified for understanding - we do not consider the formation of color and the picture itself.