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 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? How to buy eye protection lamps? Let's take a look!
Are the eye protection desk lamps on the market really useful?
With the emergence of eye protection lamps in the market, more and more consumers who pay attention to vision protection choose eye protection lamps. So, are eye protection lamps really useful? Are eye protection lamps useful? We choose from various types of eye protection lamps. The principle of eye protection lamp, let's explore the eye protection function of eye protection 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 change that the human eye can perceive is within 30Hz, and the light changes 100 times per second (from bright to dark, then from dark to bright, ...) Although we will not perceive it, but 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 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 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 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 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 finally someone invented the DC eye protection lamp, which first turned the alternating current into direct current, and used a DC ballast to light the lamp with direct current, so that it did not flicker at all. But it is not dazzling at all, very soft, and greatly relieves eyesight fatigue. And compared with other eye protection lamps, there is no electromagnetic radiation. The related technology of DC eye protection lamp has passed the invention patent certification granted by the State Intellectual Property Office. Moreover, electromagnetic radiation has no radiation compared with other types of eye protection lamps. Of course the price will not be low.
How to choose eye protection lamp
1. Appearance
The appearance of the eye protection lamp refers to the light of the eye protection lamp. The light of the qualified eye protection lamp generally does not have any stroboscopic, is softer, not dazzling, and the brightness of the light is relatively uniform.
2. Color temperature value
The color temperature value of the light emitted by the lamp determines the softness of the light. Too high or too low is not good. 4000K to 5200K is more suitable. Among them, the 4000K to 4500K eye protection lamp has a slightly reddish light, which is softer and suitable for primary school students; while the 4500K to 5200K color temperature value is suitable for middle school students and above.
3. Electromagnetic radiation
Electromagnetic radiation is invisible and intangible. It is best to fool customers. In fact, a very simple electromagnetic radiation detector can prove it, but many eye protection lamps with the banner of non-radiation are afraid to give consumers detectors. , why? There is a ghost in my heart, just from this point, we can know that this kind of eye protection lamp is not reliable in other indicators.
4. Glare
It is very easy to identify whether there is glare or not. There is glare when the lamp tube is exposed directly or only with a layer of transparent plate added, because the child will be stabbed by the strong light when sitting in front of the desk or looking up slightly, even if it is like The weak light of the flashlight will make people dizzy if you look directly at the lamp beads, not to mention the eye protection lamp, like such an obvious defect, the seller will swear to you that it is anti-glare.
5. Light height
What is the light height: it refers to the distance between the specific table top of the lamp tube. The national requirement is greater than 40 cm. Many people do not know that there is such a standard. Why is there such a standard? The height of the lamp is above the lamp, and the eyes see a bright area and a dark area, so the alternating light and dark lighting environment has a great impact on vision.
6. Material
The national regulation of eye protection lamp shade is translucent material, why use translucent material? Because the translucent material will introduce part of the light into the dark area above the lamp tube, so that the entire lighting environment will not have too strong light and dark divisions , so as to achieve the purpose of eye protection. At present, many eye protection lamps do not take this standard into account at all. They use opaque materials or recycled materials as lampshades. For a long time, toxins will be decomposed into the air, which is very harmful to human health.
7. Documents
The product qualification certificate, product safety certification certificate and other certificates of eye protection lamps should be complete, and there should be sufficient spare parts such as lamps to ensure that consumers need them from time to time. In addition, when purchasing eye protection lamps, pay attention to the CCC, which is the "3C" certification of the national security compulsory certification.
8. After-sales service
The use and maintenance of eye protection lamps are especially important. Before the sale, a shopping guide should demonstrate on the spot, and after the product is sold, there must be a real repair address and telephone number.
