1. What is stroboscopic
Stroboscopic refers to the fluctuation of the luminous flux of an electric light source at a certain frequency. Pointing at the light source with the mobile phone can often find the stripe distribution, which is caused by stroboscopic. Certain levels of flicker are not noticeable, and there is no physical discomfort; but some flickers are really problems.
As early as the 1990s, a large number of studies have found that light source flickering is closely related to neurological diseases such as migraine, headache, autism, visual fatigue and discomfort. In severe cases, it can cause illusions in the human eye, and then cause accident. Don't underestimate the strobe, different frequencies and fluctuation depths have different effects on people!
1. Visible strobe
The human eye is a very complex system, and individual differences are very large. For most people, the light flicker below 80 Hz can be perceived. At this time, the human eye can perceive the light and dark changes. The flicker frequency below 80 Hz is also called It is visible flicker. Visible stroboscopic is unacceptable for ordinary lighting or display.
♦ The human eye's sensitivity to stroboscopic weighting function
2. Stroboscopic effect
For stroboscopic above 80Hz, the human eye is not easy to detect, but it has a greater impact on the human eye's spatial perception. For example, the moving object is regarded as a series of still images, that is, the stroboscopic effect. Due to the stroboscopic effect, people will have an illusion, and it is very dangerous to regard some fast-running equipment as slow-running or even stationary.
♦ Indication of stroboscopic effect
♦ The illusion of machine operation caused by stroboscopic effect
3. Phantom phenomenon
Similarly, when the flicker frequency of the light source is 80Hz-2kHz, and the objects in the environment remain stationary, when the human eye is moving in the position or direction, the stationary light source will appear the extended light spot of the system, which is called phantom phenomenon, such as car taillights. , Or glance at the outdoor LED display, etc.
4. The hazards of stroboscopic
Light source flickering is closely related to various neurological diseases such as migraine, headache, autism, eye fatigue, and blurred vision. Studies have shown that low-frequency flicker light sources of 3-70 Hz may cause photosensitive epilepsy for some people; flicker frequencies of 100 Hz are considered to cause headaches and migraines; flicker light sources of 120 Hz frequency may affect people’s emotions, such as boredom, anxiety, etc. . The visual illusion caused by the stroboscopic effect and related mechanical movements in time is very dangerous in industrial sites. Therefore, accurate measurement and evaluation of the stroboscopic characteristics of lighting products is directly related to people's health problems, which need to be resolved urgently.
2. Why does the LED flicker?
LED lighting products are driven by AC to DC constant voltage or constant current power supply. The light source itself does not produce stroboscopic. The presence or absence of stroboscopic flicker depends on the LED driving power supply. Because the drivers are very different, the stroboscopic performance of each LED product is different. In particular, in order to save costs, some manufacturers use simpler drive circuits, such as AC LEDs, which may cause greater stroboscopic problems.
For smart lighting products, dimming is an essential function, and dimming is just another cause of strobe. When the product is loaded with the dimming function, the stroboscopic flicker tends to be further aggravated. Especially when the dimming is dark, the fluctuation depth is relatively large, as shown in the figure below. Therefore, for lighting products that have a dimming function or claim to be connected to a dimming controller, their stroboscopic performance should be measured when the dimming is the brightest and the dimming is dark.
♦ Flicker waveform of dimming LED lamps
More than ten years ago, most people would not have thought that lighting and health would have a relationship. After more than ten years of development, the LED lighting industry has gone from the pursuit of light efficiency, energy saving and cost to light quality, light The needs of health, photobiological safety and light environment. Especially in recent years, the blue light hazards caused by LEDs, human rhythm disorders, and human eye retinal damage have gradually emerged, making the industry aware of the urgent need for the popularization of healthy lighting.
Healthy lighting will become the next outlet in the LED lighting industry.
