Are the eye protection desk lamps on the market really useful?
As people pay more attention to protecting eyesight, in order to let children have good eyesight, eye protection desk lamps are more and more favored by teenagers and parents. However, the current lighting brands are mixed, which brings consumers a problem of choice. So, are the eye protection table lamps on the market really useful? Let's take a look!
Are the eye protection desk lamps on the market really useful?
With the emergence of eye protection table lamps in the market, more and more consumers who pay attention to eye protection choose eye protection table lamps. So, are eye protection table lamps really useful? Are eye protection table lamps good for use? The principle of use of the eye-protection table lamp, let's explore the eye-protection function of the eye-protection table lamp from the root.
The alternating current in China is 50Hz, that is, it changes 50 times per second. Therefore, the lights that directly use AC power are all flickering, and the flickering frequency is generally 100 times/second, which is twice the frequency of the grid, that is, 100 times per second. The changes that the human eye can perceive are within 30Hz, 100 times per second of light changes (from bright to dark, then from dark to bright,...) Although we will not perceive them, some studies have said that these changes (flickering). Movement) for the human eye, it will work. If strong light acts on the human eye, the pupil in the eye will shrink; for weak light, the pupil will dilate. Therefore, the direct application of alternating current electric light will be harmful to the eyes (referring to students who often use electric light to read).
①High frequency lamp
Someone invented the high-frequency light, which changes tens of thousands of times per second. Since human eyes have no time to change with it, they can't feel the change at all, so it can be said to be "unchanged" and achieve the purpose of eye protection. Convert ordinary 50Hz alternating current into high frequency alternating current and use electronic frequency conversion. That is, in high-frequency lamps, the 50Hz alternating current is actually converted into high-frequency alternating current, and then the high-frequency alternating current is used to light the lamp.
However, the electromagnetic radiation of high-frequency electricity will also increase, that is, the electromagnetic radiation of high-frequency lamps is larger than that of ordinary incandescent lamps and fluorescent lamps, which may also cause another kind of damage. In addition, high-frequency flash does not mean no flash.
②More advanced eye protection desk lamp
An upgraded version of the high-frequency lamp, taking into account the impact of light reflection on the human eye. If some filters are added, it can effectively increase the required light and reduce the unnecessary light. But there is still no way to completely solve the problem of strobe.
③Electric heating lamps (incandescent lamps, halogen lamps)
Ordinary incandescent lamps are actually an eye protection desk lamp. Because the alternating current heats the filament first, the filament heats up, and then emits light. Because the filament has a heat capacity, the filament is still hot when the power supply changes, and the light and dark changes will not be as intense as fluorescent lamps (fluorescent lamps). Therefore, there is an eye protection table lamp that uses a filament with a large heat capacity.
Judging the heat capacity of the filament, it can be seen intuitively: after the lamp is turned on, the lamp lights up slowly, that is, the heat capacity is large; the heat capacity is small when it is turned on. This kind of eye protection table lamp using a filament with a large heat capacity often has two gears, first turn on the low-grade heating filament, then turn on the high-grade, and use it normally. Because when the light is first turned on, the filament is not too hot, the current will be relatively large, the filament is easy to burn, and the life of the bulb is not long. Use two gears to heat the filament first, and then turn on the high-grade normal lighting, which can effectively prolong the service life.
④DC light
So in the end someone invented the DC eye protection desk lamp, which converts the alternating current into direct current first, uses a direct current ballast, and uses direct current to light the lamp, so that there is no flicker at all, and it is truly flicker-free, and the light is close to natural light when used, very bright, But it is not dazzling at all, very soft, and greatly relieves eyesight fatigue. And compared with other eye protection desk lamps, it does not have any electromagnetic radiation. The technology related to the DC eye protection table lamp has passed the invention patent certification granted by the State Intellectual Property Office. Moreover, electromagnetic radiation does not have any radiation compared with other types of eye protection desk lamps. Of course the price will not be low.
