led lighting flicker

After more than ten years of development, the LED lighting industry has risen from the pursuit of light efficiency, energy saving and the cost to the demand for light quality and light health. In particular, in recent years, the problem of retinal damage to the human eye are caused by LED Lightings, and it has become increasingly apparent, making the LED industry realize that the importance of health lighting . When assessing the impact of LED light sources on the human eye, it is inevitable to mention stroboscopic, with the advancement of electric light source technology and people’s understanding of photobiology, solving the problem of stroboscopic is undoubtedly a key to achieving healthy lighting. Today, we will take you to learn the problems related to LED flicker, and answer the causes, hazards, measurement methods and solutions in LED lighting!

1. What is Flicker?

“Flicker” refers to the fluctuation of the luminous flux of light source at a certain frequency. The distribution of stripes can often be found by aligning the light source with the mobile phone, which is caused by flicker. Severe flicker can create illusions in the human eye, which in turn can lead to accidents. Don’t underestimate the led lighting flicker, the impact of different frequencies and fluctuation depths on people are not the same!

Visible Flicker

The human eye is a very complex system, individual differences are very large, for the vast majority of people, they can perceive the flicker of light < 80Hz, at this time the human eye can perceive the change of light and shade, the flicker frequency below 80Hz is also known as visible flicker. Visible flicker is unacceptable for normal lighting.

Flicker effect

For stroboscopic flashes 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, a moving object is seen as a series of still images, known as stroboscopic effects. Due to the strobe effect, people will have illusions, and it is very dangerous to think of some fast-moving equipment as slow running or even stationary.

2.what cause LED Lightings Flicker?

The two main problem is the constant current power supply and LED quality.

Power supply problem

Without a suitable electronic circuit, such as a ballast, driver or power supply, the light source will produce flicker, and the greater the fluctuation of the output luminous flux, the more serious the strobe. LED lighting systems using AC to DC constant voltage or constant current power driver, the light source itself will not produce flicker, it depends on the LED power supply . Each LED product stroboscopic performance is also different. In particular, in order to save costs, some manufacturers use a relatively simple driving circuit, which will have a large flicker problem.

LED quality problem

The quality of the LED is poor, the single chip is less than 1W, and the wattage of the lamp is virtual, so that the chip also drives mismatch and works abnormally, resulting in flicker. For smart LED lightings, dimming is its essential function, and dimming is another cause of stroboscopic. When the product loads the dimming function, the strobe tends to be further aggravated. Especially when the dimming is dark, the fluctuation depth is relatively large. Therefore, for lighting products with dimming functions or claiming to be able to connect dimming controllers, their stroboscopic performance should be measured when the dimming is the brightest and the dimming is dimmed, respectively.

2. What are the health effects of Lighting flicker?

Lighting flicker has a stimulating effect on the human visual system, which will make people uncomfortable feelings, usually flashing according to people’s feelings are divided into visible flickering and invisible flickering. When the frequency is > 100Hz, the human eye cannot feel the flickering phenomenon, but it will still cause eye fatigue, headache, etc., which is the consequence of stroboscopic, and it is generally believed that this effect exists within 500Hz. So, what harm will people do to work or live in a flickering light environment for a long time? The main hazards are reflected in two major aspects: human health hazards and safety health hazards (this harmful effect is a long-term effect, chronic accumulation process)

01 Human hazards it include headaches, migraines, fatigue; increased intraocular pressure, decreased visual efficacy of the eyes, blurred vision, decreased, distraction; neurological problems, such as photosensitive epilepsy.

02. Safety hazards

such as optical illusions, including rotating machines, road lighting, and car lights. Studies have shown that different degrees of stroboscopic will have an impact on people’s physiology and psychology, of course, most of the negative, such as damage to vision, emotional irritability, induced epilepsy and so on.

4. how to measure stroboscopic?

You can use the phone camera function to identify whether there is a flicker. Open the phone’s camera and point at the lighting under test, and determine whether the product has a strobe by observing whether there are any streaks on the phone screen. To scientifically and quantitatively evaluate the stroboscopic problem, it is still necessary to have professional measuring equipment. According to the requirements of the standard, the measurement of stroboscopic should use a photometric probe to collect data, and the sampling rate should be at least 2kHz or more, the faster the better.

5. How to solve the flicker problem?

With the continuous advancement of modern lighting technology and the continuous awakening of people’s awareness of healthy lighting, having a healthy light environment has become the basic demand of the public. When we buy led lighting fixtures, we need to try to choose LED brand as light source, and let the merchants show the corresponding test reports, last choose High PF high quality led driver, best one is isolated constant current led driver.

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