① Most of them: improve the low-frequency flash to high-frequency flash, adopt variable frequency electronic ballast, improve the electric frequency from 50H z to 5,500 Hz, 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 does not feel stroboscopic discomfort, thus reducing visual fatigue. The less stroboscopic, the better the lighting effect.
(2) Very few: first, change AC to DC, use DC ballast, and use DC lighting, which will not flash at all, so as to achieve true no stroboscopic, and when used, the light is close to natural light, very bright, but not dazzling at all, very soft, which greatly relieves visual 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 China National Intellectual Property Administration.
High-frequency ballast for high-frequency lamps, the alternating current in China is 50Hz, that is, it changes 50 times per second. Therefore, all lamps directly using alternating current are flashing, and the flashing frequency is generally 100 times/second, which is twice the frequency of the power grid, that is, it changes 100 times per second.
The changes that human senses can perceive are within 30Hz, and the light changes (from bright to dark, then from dark to bright, ...) per second 100 will not be noticed by us, but some studies have said that these changes (flicker) will have an impact on human eyes.
If strong light acts on people's eyes, the pupils in the eyes will contract; For low light, the pupil will be dilated.
Therefore, direct use of alternating current lamps will do harm to eyes (referring to students who often read books with electric lamps). 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" to protect their eyes.
Change the ordinary 50Hz alternating current into high frequency alternating current, and use electronic frequency conversion. That is, in high-frequency lamps, 50Hz alternating current is actually changed into high-frequency alternating current first, and then illuminated by high-frequency alternating current.
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 harm.
② Electronic high frequency lamp
Use high-frequency electronic ballast and upgraded high-frequency lamp, considering 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 Electric 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 drastic as that of fluorescent lamp.
So there is an eye protection lamp, which uses a filament with a large heat capacity.
Judging the heat capacity of filament can be seen intuitively: after turning on the light, the light will light up slowly, that is, the heat capacity is large; It is bright when it is turned on, and its heat capacity is small.
This kind of eye protection lamp using filament with large heat capacity often has two gears, first turn on the low-grade heating filament, and then turn on the high-grade one for normal use. Because the filament is not too hot when turning on the light, the current will be relatively large, the filament will burn easily, and the life of the bulb will not be long. Using two stages 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 can only be used in places where it is inconvenient to access the power supply, such as night market vendors, trains, ships, buses, outdoor lighting, etc. Due to the shortcomings of short life, low luminous efficiency, short lamp life and electrophoresis phenomenon, emergency lamps are not used under normal conditions with AC power supply. At present, some manufacturers apply this technology to eye protection lamps and store alternating current through batteries. Because the output current is unstable, the stored power is unstable. It is not recommended when there is electricity.
⑤ DC eye protection lamp
So finally, someone invented DC eye protection lamp and used DC ballast. By first converting alternating current into DC with stable voltage and current, it does not flash at all, thus realizing true stroboscopic-free. Moreover, the light emitted in the process of use is continuous, uniform and bright like natural light, but it is not dazzling at all and very soft, which greatly relieves visual fatigue and solves the stroboscopic problem of inductive ballast fluorescent lamp that damages vision. Because of DC technology, 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 reluctant to adopt this technology.
How to choose eye protection lamp
There are three ways to choose eye protection lamps. Look at the appearance first: this appearance refers to the light of the eye protection lamp. Generally qualified eye protection lamps have no stroboscopic light, are soft and not dazzling, and the brightness of light is relatively uniform. Second, we must look at the documents, such as the product certificate of eye protection lamp, product safety certification certificate, etc. We must have enough lamps and other spare parts to ensure that consumers need them in an 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 live demonstration by a shopping guide, and after the product is sold, there should be a real maintenance address and telephone number. In a word, if you want to buy a real eye protection lamp, you have to keep your eyes open and choose it in a shopping mall with a certain scale. Finally, attention should be paid to CCC, "3C", the symbol of national security compulsory certification when purchasing eye protection lamps.
How to test the stroboscopic of eye protection lamp
Strobe test tips: (1) You can do a simple test by taking photos with your mobile phone or camera, and strobes such as ordinary desk lamps or fluorescent lamps can be clearly seen 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 speed, but are stable halo patterns and color phenomena, indicating that the lights are not stroboscopic; If the special detection gyro produces multiple rings with different colors, each ring will change with the rotation speed of the gyro, which shows that the lamp produces stroboscopic light, and the stronger the color, the greater the harm of stroboscopic light and stroboscopic effect.