If at the dawn of the development of computer technology, the presence of a personal computer at home indirectly testified to the security and outstanding mathematical abilities of its owner, then in the last two decades the situation has changed dramatically. A computer and a laptop have become as familiar attributes of modern life as an automatic washing machine or mobile phone. Not surprisingly, forums on the global web are increasingly asking why the monitor flickers. With a small number of users, some did not pay attention to it, while others did not notice at all. And after more than half of the global population joined the virtual community, topics began to be created with the loud name of โmonitor flickering!โ. At first glance, it might seem that the flicker problem is a thing of the past, disappearing with bulky monitors based on cathode ray tubes (CRTs), but is it that simple?
If the monitor flickers, this creates an additional burden on the organs of vision, and given the duration of work on the computer, this issue is very important. To understand it and, finally, dot the โandโ, perhaps itโs worth starting with a short excursion into history.
For a long time, all computer monitors were created on the basis of CRT. This technology simply had no analogues. Although such display devices brilliantly coped with the tasks, many users often stated that the monitor was flickering. They were absolutely right. The principle of CRT operation is that several streams of electrons controlled by magnetic fields fall on the inner surface of the tube, covered with a special composition. At the point where the streams hit, the composition (phosphor) begins to glow. The rays seem to draw line by line, moving from top to bottom. Then everything repeats.
The term "monitor frequency" indicates how many times per second the rays create a picture on the screen. Thanks to the inertia of vision, the illusion of a holistic image is created. Most people see flickering at a frequency of less than 75 hertz, although it all depends on physiological characteristics. You can learn more about the work of CRT on specialized sites and in print media. So, you can eliminate the flickering of a CRT monitor by selecting a higher frequency in the driver settings of the video card.
But currently the more interesting question is why the LCD monitor flickers. In many forums, serious debate erupts in this regard. But at the time of the appearance of the LCD (liquid crystal) technology, it was claimed that the flicker problem was completely solved, since the principle of constructing the picture is completely different. It turned out that in this case, manufacturers are a little cunning, offering half the truth. But the thing is this. The matrix itself, in which the cells of liquid crystals are enclosed , does not really flicker, creating a static image every moment.
Everyone is familiar with electronic watches (remember the famous Montana brand). The eye strain when looking at the numbers is exactly the same as when studying the text on a piece of paper (of course, if you do not take into account the difference in size). Everything is true here. But the problem is that the image formed by liquid crystals becomes visible only if there is a light source placed on the back side. In watches, this is the external illumination reflecting from the substrate, but the backlight is built into the monitors. Now they are being actively replaced by LED lines. In most models of LCD monitors, the brightness adjustment of these sources is achieved by modulating the power pulses, which leads to flicker. Of course, the frequency does not fall below 140 Hz (usually beyond 200), but it is and is felt by the organs of vision as discomfort. Solution: choose models without PWM or set the brightness to 100%.