It is also a year of "3.15", and it is also the International Consumer Protection Day.
On March 15, Premier Li Keqiang said at the National People's Congress press conference: "We want to praise the quality products and pull the bad profiteers' black. We work together to make our quality products more and more day by day. Our life is better every year."
A warm-hearted discourse, witnessing the state's attitude of perfecting the supervision of counterfeiting and optimizing the quality of life of consumers. I believe that at the 3·15 evening party this year, CCTV No. 1 consumer warning LED learning lights are receiving much attention.
The staff of the Guangdong Quality Inspection Institute demonstrated the LED learning light. It was found by the instrument that the high-frequency flashing learning light was very harmful to the eyes, but it was difficult to detect with the naked eye.
According to this researcher, the main reason for the strobe of the LED learning lamp is the internal driver IC chip. The LED learning lamp with the chip on the market has a price difference of 3 to 4 times compared with the chip without the chip.
The driving power is the culprit "the culprit"
For the reason why stroboscopic LED lights appear, Gaogong LED also investigated this issue.
According to Zhang Hong, general manager of the inductive testing, "the strobe of LED lamps has nothing to do with the LED light source, mainly caused by the driving power supply. According to common sense, the LED light is DC power supply, and should not flash, but if the power supply In the process, the power supply is not completed, and the low-frequency harmonics superimposed in the DC, there are fluctuations, there will be stroboscopic phenomenon."
In fact, 90% of the lights on the market today are strobed, but the severity of the strobe is different, so the strobe is mainly measured by the Flicker index or the Percent flicker.
"All in all, the stroboscopic constraints are mainly two factors. The first is the level of the flicker frequency, and the second is the amplitude of the flicker modulation." Zhang Hong told Gaogong LED.
Wang Xianghui, general manager of Zhixiang Technology also believes that "the strobe is mainly caused by excessive power supply current ripple. In addition, if the LED lamp bead is not in continuous conduction, the camera will also shoot stroboscopic phenomenon."
Then, for the stroboscopic phenomenon of LED lights, how to solve it? Fan Zhikai, general manager of Zhuo Naipu, proposed that “through the peripheral circuit method, stroboscopic can be avoided. And, as early as 2014, the strobe problem has been solved. ."
Mobile phone test strobe is not scientific
In normal life, if you want to detect whether the light bulb has a screen flash, it is very simple. Pick up the phone and use the lens to aim at it. Pay attention to the flicker on the screen and you can know what kind of LED light bulb does not flash. For this statement, LED industry insiders have said that this is unscientific.
Zhang Hong said frankly, "It is unreasonable to use a mobile phone to test strobe, because the mobile phone is not specially designed for stroboscopic testing. The camera sampling rate and image processing program used by each mobile phone manufacturer determine whether or not stroboscopic, test frequency can be seen. Flash has certain sampling rate and bandwidth requirements for the device. Using a mobile phone to see the luminaires will have different effects on the screen at different distances and different angles." So use the mobile phone camera to judge the presence or absence of strobe. Does not meet the sampling requirements.
Indeed, the same light, using different mobile phones to detect, the results are not the same, so the use of mobile phone camera to determine the presence or absence of stroboscopic, is not in accordance with sampling requirements.
Wang Yanhui also suggested that "LED lamp stroboscopic testing requires professional instruments for testing. For consumers, there is no professional instrument. Using mobile phones for testing is a way, but it cannot quantify the degree of stroboscopic response."
Cutting corners is the primary cause of quality problems
It is understood that in addition to stroboscopic phenomena, color temperature, color rendering, illumination, etc. are also considerations for the quality of LED lamps.
According to Zhang Hong, "Now most of the regular driver IC manufacturers have considered the stroboscopic problem in the circuit of the product, try to suppress the low-frequency harmonics, and produce the luminaire driver IC that meets the testing standards. As long as it is not cutting corners, the LED lamps produced can basically meet the requirements of the standard. Some unqualified products are mostly caused by the use of cheap design solutions."
At present, LED luminaires used for export to the North American market have added stroboscopic testing requirements in the regulations, but many other testing certifications have not yet formed a unified indicator. This is a slowly improving process and still needs everyone to work together. Discussion and exploration.
"We have no stroboscopic linear solution, which can completely solve the stroboscopic problem. Whether it is using a mobile phone or a professional instrument, there is no problem." Wang Yanhui said.
I believe everyone has noticed that in the past two years, the export of LED lamps has been forcibly recalled, which is also the "dysentery" of domestic lighting products.
In Zhang Hong’s view, “the quality problems of export products, overheating, fire, and electric shock risk are the main factors, and are rarely recalled due to performance reasons such as stroboscopic lighting or color brightness. Overheating, fire, and electric shock are serious safety hazards. , causing harm to consumers' lives and property safety."
The reason why LED lamps are exposed to heat and electric shock is mostly due to the use of materials with poor fire resistance and heat resistance and inferior original materials. The company has cut corners in order to save costs.
"To solve the phenomenon that LED lamps are recalled due to quality problems, LED lighting companies need to be professional, and they cannot cut corners in order to save costs." Fan Zhikai mentioned last.
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