After reading in fluorescent lamp over a long period of time, people always feel uncomfortable, even though the luminance is nearly the same with day. What’s the reason? Some research found that the luminous intensity of fluorescent lamp is changing with time and it is named the flicker of light source.
Then what is stroboscopic effect of light source? It means the light that is given out by light source presents rapid and repeated variation with the time passing by which make the light instability. Of course, it is not easy to observe the flicker of light source by eyes and it mainly depends on the frequency of flicker. In general, our eyes are able to perceive the light flicker if the frequency is less than 50Hz, while 8.8Hz is the most sensitive to eyes. Meanwhile, the frequency of flicker is varying with the light strength which is emitted by light source but not in direct proportion. When the frequency is over than 50Hz, the majority of people are difficult to distinguish whether the light source is twinkling or not because the emitting light is stable and continuous and the reflection of our eyes are unable to keep pace with the variation of light source. For example, our eyes rarely sense the stroboscopic effect if the frequency is 120 times per second.
In theory, all light sources that use alternating current exists stroboscopic effect and there’s no exception with LED light. The eye protection lamp in the market declares without flicker but in fact it is not the case. LED is to change the flicker of ordinary alternating current into a higher frequency of flicker by special device to decrease the influence of eyes and protect them but from beginning to the end, flicker always exists. In addition, high-frequency treatment would generate strong electromagnetic wave to damage our health. Even eye protection lamp is like this, not mention to led high bay and other fixtures.