Why the monitor flickers

If at the dawn of the development of computer technology the presence of a personal computer home indirectly indicated the security and outstanding mathematical abilities of its owner, in the last two decades the situation has radically changed. The computer and laptop have become the same familiar attributes of modern life as an automatic washing machine or mobile phone. It is not surprising that on forums in the global network, the question of why the monitor flicker is increasingly asked. With a small number of users, some did not pay attention to this, others did not notice at all. And after more than half of the world population joined the virtual community, they began to create themes with a loud name "the monitor flickers!" At first glance, it may seem that the flicker problem has remained in the past, disappearing along with cumbersome CRT monitors, but is it really that simple?

If the monitor flickers, this creates an additional burden on the eyes, and if you take into account the length of time you work at the computer, this issue is very important. To understand it and, finally, to dot the "and", perhaps, it is worth starting with a small excursion into history.

For a long time, all computer monitors were created on the basis of CRT. This technology simply did not have any analogues. Although with such tasks, such information display devices were coping brilliantly, many users often stated that the monitor flickers. They were absolutely right. The principle of the CRT is that several streams of electrons, controlled by magnetic fields, fall on the internal surface of the tube, covered with a special composition. At the point where the streams hit, the composition (phosphor) begins to glow. Rays like drawing a line by line, moving from top to bottom. Then everything repeats itself.

The term "monitor frequency" indicates how many times per second the beams create a picture on the screen. Due to the inertia of vision, an illusion of a holistic image is created. Most people see flicker at a frequency of less than 75 Hertz, although it all depends on the physiological characteristics. More details on the work of CRT can be found on specialized websites and in printed publications. So, you can eliminate the flicker of the CRT monitor by selecting a higher frequency in the driver settings of the video card.

But at the moment the question of why the LCD monitor flickers is more interesting. In many forums on this issue, serious debates are raging. But in fact at the time of LCD (liquid crystal) technology it was stated that the problem of flicker is completely solved, since the principle of constructing a picture is completely different. It turned out that in this case the producers are a little cunning, offering half the truth. And here's the thing. The very matrix, in which the cells of liquid crystals are enclosed , does not really flicker, every moment creating a static image.

With an electronic wristwatch everyone knows everything (remember the famous brand "Montana"). The load on vision when looking at the numbers is exactly the same as when studying text on a sheet of paper (of course, if you do not take into account the difference in size). Here everything is true. But the problem is that the image formed by liquid crystals becomes visible only in the presence of a light source placed on the reverse side. In the clock, this is the external illumination reflecting from the substrate, but the backlight lamps are built into the monitors. Now they are actively replaced by LEDs. In most models of LCD monitors, brightness adjustment of these sources is achieved by modulating the power pulses, which leads to flickering. Of course, the frequency does not fall below 140 Hz (usually 200), but it is and is felt by the organs of vision as discomfort. Solution: choose models without PWM or set brightness to 100%.