① Most of them: raise the low-frequency flash to high-frequency flash, adopt variable frequency electronic ballast, raise the electric frequency from 5H z to 5,5 Hz to reduce the stroboscopic effect, and adopt tricolor phosphor to reduce the glare effect, so that the light is soft and not harsh, so that the human eye can not feel the stroboscopic discomfort, thus reducing the visual fatigue. The less stroboscopic, the better the lighting effect.
② Very few: change the alternating current into direct current first, use direct current ballast, and light the lamp with direct current, and it will not flash at all, so as to achieve true no stroboscopic. Moreover, when in use, the light is close to natural light, very bright, but not dazzling at all, very soft, which greatly relieves vision fatigue. But also has no electromagnetic radiation compared with other eye protection lamps. The related technology of DC eye protection lamp has passed the invention patent certification granted by China National Intellectual Property Administration.
high frequency ballast is used for high frequency lamps, and the alternating current in China is 5Hz, that is, it changes 5 times per second. Therefore, all electric lights that directly use alternating current are flashing, and the flashing frequency is generally 1 times per second, which is twice the frequency of the power grid, that is, it changes 1 times per second.
The changes that the human senses can perceive are within 3Hz, and 1 light changes per second (from bright to dark, then from dark to bright, ...) will not be perceived by us, but some studies have said that these changes (flashing) will have an effect on the human eyes.
If strong light acts on people's eyes, their pupils will contract; For low light, the pupil will be dilated.
Therefore, direct application of alternating current electric light will do harm to eyes (referring to students who often use electric light to read books). Someone invented the high-frequency lamp, which changes tens of thousands of times per second. Because people's eyes can't change with it, they can't feel the change at all, so they can be said to be "unchanged" and achieve the purpose of protecting their eyes.
change ordinary 5Hz alternating current into high frequency alternating current, and use electronic frequency conversion. That is, in high-frequency lamps, 5Hz alternating current is actually changed into high-frequency alternating current first, and then high-frequency alternating current is used for lighting.
However, the electromagnetic radiation of high-frequency electricity will also increase, that is, the electromagnetic radiation of high-frequency lamps is greater than that of ordinary incandescent lamps and fluorescent lamps, which may also cause another kind of harm.
② Electronic high-frequency lamp
High-frequency electronic ballast is used, and the upgraded version of high-frequency lamp takes into account the influence of light reflection on human eyes. If some filters are added, the required illumination can be effectively increased and the unnecessary illumination can be reduced. But there is still no way to completely solve the problem of stroboscopic.
③ electrothermal lamp
Ordinary incandescent lamp is actually a kind of eye protection lamp. Because alternating current heats the filament first, the filament heats up and then emits light. Because the filament has heat capacity, when the power supply changes, the filament is still hot, and the change of light and shade will not be as intense as that of fluorescent lamps (fluorescent lamps).
Therefore, there is an eye protection lamp, which uses a filament with large heat capacity.
judging the heat capacity of the filament, it can be seen intuitively: after turning on the light, the lamp lights up slowly, that is, the heat capacity is large; When it is turned on, it is bright, and its heat capacity is small.
This kind of eye protection lamp using filament with large heat capacity often has two steps, first turn on the low-grade heating filament, and then turn on the high-grade one, which is normal for use. Because when the light is turned on, the filament is not too hot, the current will be relatively large, the filament will burn easily, and the life of the bulb is not long. Using two gears to heat the filament first and then turn on the high-grade normal lighting can effectively prolong the service life.
④ Emergency lighting
The battery is only used in places where it is inconvenient to access the power supply, such as night market vendors, trains, ships, buses and outdoor lighting. Due to the shortcomings of short life of emergency lamps, low luminous efficiency, short lamp life and electrophoresis phenomenon, it is not used under normal conditions with AC power supply. At present, some manufacturers apply this technology to eye protection lamps and store AC power through batteries. It is not recommended when there is electricity.
⑤ DC eye protection lamp
So at last, someone invented DC eye protection lamp. By using DC ballast, alternating current is first converted into DC with stable voltage and current, and then the lamp is lit with DC, so that it doesn't flash at all, and the light emitted during use is as continuous and uniform as natural light, bright, but not dazzling at all, which greatly relieves vision fatigue and solves the problem that inductive ballast fluorescent lamps damage vision. As the DC technology is adopted, there is no fluctuation, which avoids electromagnetic radiation and electromagnetic pollution caused by high-frequency oscillation of high-frequency electronic ballast fluorescent lamp. However, the process of DC fluorescent lamp is difficult and the cost is high, so many enterprises are unwilling to adopt this technology.
How to choose eye protection lamps
There are three ways to choose eye protection lamps. First, look at the appearance: this appearance refers to the light of eye protection lamps. Generally, the light of qualified eye protection lamps has no stroboscopic light, which is soft and not dazzling, and the brightness of the light is relatively uniform. Second, we must look at the documents, such as the product certificate of eye protection lamp, product safety certification certificate and so on, and there must be enough spare parts such as lamps to ensure that consumers need them in case of emergency. Third, it depends on after-sales service: the use and maintenance methods of eye protection lamps are particularly important. Before the sale, there should be a guide to demonstrate on the spot, and after the product is sold, there must be a real repair address and telephone number. In a word, if you want to buy real eye protection lamps, you have to open your eyes and choose them in shopping malls with a certain scale. Finally, when purchasing eye protection lamps, we should pay attention to CCC, "3C", the symbol of national security compulsory certification.
How to test the stroboscopic light of eye protection
Tips for stroboscopic test: (1) You can do a simple test with the camera state or the camera state, and the stroboscopic light such as ordinary desk lamp or fluorescent lamp is obviously visible on the screen. (2) Put the special detection gyro under the lamp to rotate. If you look at the black and white patterns on the detection gyro, they do not change with the rotating speed, but are stable halo patterns and color phenomena, which indicates that the lights are not stroboscopic; If the special detection gyro produces multiple rings with different colors, and each ring will change with the rotation speed of the gyro, it shows that this lamp produces stroboscopic, and the stronger the color, the more harmful the stroboscopic and stroboscopic effects are.