Our eyes are not badly protected from harmful radiation - for example, ultraviolet light - hitting the retina. The protective function in this case is performed by the pupil, which dilates in the dark and narrows in bright light, preventing solar radiation from dissolving into the retina. Only this works well in natural conditions when harmful radiation is related to the brightness of light.
In artificial cases, the protective functions lose their effectiveness. For example, when a person walks into a room and interacts with a source of harmful radiation in dim light. Then the pupil remains dilated and does not prevent the same ultraviolet or other bad radiation from entering the eye - for example, blue radiation from modern liquid crystal panels used in smartphones, smartwatches, and TVs. And that's where artificial shielding or blue light reduction technologies come in.
About blue light
For some time, manufacturers of electronics with displays began to actively implement technologies to reduce blue light at the software level. At first, society perceived this as a marketing move, but later scientists gave an understandable explanation. Our body produces melatonin - the so-called "sleep hormone". If its concentration is high, a person wants to sleep, otherwise - awake.
The amount of this substance is regulated based on many factors, including the intensity of light, as well as its characteristics. Namely, the level of melatonin is affected by blue light, the wavelength of which is between 380 and 500 nanometers. This is the kind of blue-violet radiation that is the most powerful in the spectrum and is highly fatiguing to the eyes. The more blue light we see, the less melatonin becomes in the body and the less we want to sleep. If there is no or very little blue light, the body takes this as a command to produce the sleep hormone.
More often than not, we stare at our smartphone screen in bed, right before we go to sleep. And we can't sleep because we absorb harmful blue light. For this reason, manufacturers began looking for ways to reduce the intensity of blue light. And they did.
How it works
Everything is quite simple - to exclude or at least minimize the blue light in the eyes, you need to filter it with special films, or glasses (for example, glasses with a protective coating) or try to turn it off. In other words, replace the wavelengths of the 380 to 500 nm range with other, less harmful, and intense ones. For example, reduce the temperature (white balance) and turn the cold blue light into warm and yellowish with the help of settings in the TV menu. But watching in this mode 4K and HDR is somehow unusual - the picture becomes implausible in terms of color reproduction.
To get out of this situation, manufacturers began to produce TVs that do not emit harmful spectrum. More precisely, they do, but within the authorized limits. These norms, in turn, are set by two international "committees" - TUV Rheinland and SGS. According to the rules, modern matrices should emit no more than a few percent of the harmful blue spectrum, replacing it with waves of another, less harmful range.
The blue color can be formed in several ways. The first and easiest is to make the entire range from 380 nm to 500 nm glow. The second is to cut everything shorter than 400-420 nm and leave the wavelengths in the range from 420 nm to 500 nm, increasing their power for a brighter and more intense glow. In both cases, the human eye will see the blue color, only in the first case "dirty", and in the second - maximally purified from unnecessary "impurities". The latter method is now used by manufacturers of equipment to reduce the amount of harmful radiation.
How to find a "safe" TV set
In the case of the topic of harmful radiation the head of the question is the presence of technology to protect vision. And here the old rule works — the "higher" the TV set in the line, the more likely it is that it will be realized protection according to the TÜV standard. Models with protection are marked with special icons. Usually, they are marked on the front panel sticker and also advertised in detail on the TV's homepage.
Not all manufacturers put high-quality diodes with minimized radiation only in top matrices. Protection technologies are used in Hisense TVs with a wide variety of matrices — it does not matter whether it is OLED, QLED, or even ordinary LCD.
But, if you consider buying TVs from any other manufacturers, you can make an accurate guess with the choice of a "protected" model if you consider buying a QLED version - that is, a TV on quantum dots. This technology uses backlight diodes by default, maximally limited in "harmful" ranges. Samsung, for example.
Also, limited emission of harmful waves of the blue spectrum has devices based on OLED-matrixes.
These panels practically do not "blue" even without various tricks and additional technologies - this is the nature of organic LEDs.
Certification is not the solution, although it can also partially make a useful contribution. Scientists are still battling not for the amount of melatonin in the body, but about the health of his vision. It is believed that the light from 415 to 455 nm is dangerous, and everything below - is even more harmful. Manufacturers of TV sets and other equipment are trying to protect us from this harmful effect.
It is also worth mentioning that the presence of a certificate from the same TÜV Rheinland and SGS in a particular model of TV does not mean that you will buy a device that will be saturated yellow on the screen. That's what a lot of people think and they are wrong. No, visually you will not notice any difference in the quality and accuracy of color reproduction, but after a long viewing (especially in a dark room) your eyes will not get tired so much