Risks of LED lamps in abnormal use

As the country's strength increases, more and more preferential policies are being granted to rural areas, and the support for rural development is increasing. Therefore, the rural lighting market has huge potential to be tapped. Under the premise of the rapid development of LED technology, the cost of various components of LED lamps has been greatly reduced in the past year . However, recent test results show that some LED lamps on the market do have certain risks when used abnormally. Are LED lamps , known as the fourth-generation light source , really unsafe? Can LED blue light overflow cause damage to the retina? What exactly is LED blue light overflow? Is it a "potential killer" that hurts people? The reporter conducted an investigation on this.

　　Does LED blue light hurt the eyes?

　　Experts say it is unreasonable to equate "blue light" with "retinal damage"

　　LED, known as the fourth-generation light source, has achieved explosive growth in recent years, driven by both industrial capital and government subsidies. However, the safety issues of LED have caused anxiety among some medical professionals, with some experts worrying that "LED blue light will damage the retina."

　　Data shows that China has become one of the world's largest producers of LED lamps. The " 12th Five-Year Plan for the Development of Semiconductor Lighting Technology" issued by the Ministry of Science and Technology in 2012 stated that by 2015, the share of LED in the general lighting market will reach 30%, and the scale of the domestic semiconductor lighting industry will reach 500 billion yuan. These stimulus policies have enabled the development of China's LED industry to catch up with developed countries such as Europe and the United States.

　　However, some medical experts have expressed concern that many LED lamps on the market have the problem of blue light overflow, which can cause irreversible damage to the human retina over time.

　　Yu Anqi, deputy director of the Shanghai Lighting Product Quality Supervision and Inspection Station and chairman of the Shanghai Illumination Society, said that blue light is a light that has always existed in nature and is an important component of sunlight. It is also present in various white light sources. We live in an environment where "blue light" is everywhere, so it is unreasonable to equate "blue light" with "retinal damage." However, many LED lamps on the market currently emit blue light through chips, which excite yellow phosphors to blend into white light. This makes the blue light spectrum of white light LED lighting products richer than other light sources. "It is precisely because of the rich blue light spectrum of white light LED lighting products that international standards for photobiological hazards have been established to indicate the safety that products should achieve."

　　How to make LED safe?

　　The national standard limit is based on experimental data for adults and 8 hours of exposure.

Are LED products　　on the market safe? What is blue light spill? How can special groups use them in a healthy way? The reporter conducted an investigation.

　　The Shanghai Quality and Technical Supervision Bureau recently organized a testing agency to conduct risk monitoring on some commercially available LED lighting products. It was found that among the 27 LED lamp samples, one sample reached medium risk under abnormal usage conditions, that is, it caused damage to the retina when the eyes looked directly at the light source at close range.

　　Yu Anqi introduced that the 27 LED samples sampled included table lamps , spotlights , downlights , flat panel lights and bulbs. According to the resolution DSH 0744 of IECEE CTL (International Electrotechnical Commission - Laboratory Committee), the blue light hazards were determined. Among them, under normal use, 14 belonged to Class 0 with no danger, and 13 belonged to Class 1 with low danger, all of which were within the safe range. However, if used in abnormal conditions, that is, the front light diffuser was removed, one reached Class 2 with medium danger.

　According to experts, my country has the national standard GB/T 20145-2006 "Photobiological safety of lamps and lamp systems", which clearly introduces the hazards of blue light and the quantitative calculation method. However, this standard is currently only recommended and has no mandatory binding effect on manufacturers.

　　Professor Mou Tongsheng, a member of the International Committee for Standardization of Photoelectric Radiation Safety who participated in the preparation of the above standards, introduced that the current national standard limit is based on experimental data of adults and 8 hours of exposure, and has not yet taken into account the cumulative long-term effects of light on the human body and certain special groups, such as infants and young children who may look directly at the light source for a long time, causing damage to the retina. Therefore, although the standard stipulates that both Class 0 (non-hazardous) and Class 1 (low-hazardous) products are safe to use, Class 0 products should be used for special groups.

　　Expert advice

　　LED supervision urgently needs to implement mandatory national standards and carry out risk monitoring across the country

　　Many experts suggested that the current "Photobiological Safety of Lamps and Lamp Systems" standard be adjusted from a recommended standard to a mandatory standard, and risk monitoring should be carried out nationwide. In addition, the color temperature applicable to LED lighting products in different places should also be specified.

　　Yu Anqi said that the current "Photobiological Safety of Lamps and Lamp Systems" standard in my country is equivalent to the currently valid international standard version, and is also the standard implemented by all developed countries. "In terms of standards, we are in sync with Western developed countries and are not lagging behind."

　　Mou Tongsheng suggested that the recommended national standard "Photobiological safety of lamps and lamp systems" be adjusted to a mandatory national standard to reduce the risk of lighting products posing a threat to human health and safety.

　　Yu Anqi said that in the case that power-type LED lighting products may reach Class 2 hazards, risk monitoring of blue light hazards of LED lamps and "bathroom heater" products should be carried out nationwide for indoor LED lighting products to enable LED lighting products to develop in a healthy direction.

　　Zhang Haicong, honorary chairman of the Shanghai Illuminating Engineering Society, pointed out that the color temperature of indoor LED lighting products should not exceed 4000K, and LED lighting products with a color temperature of 5000K and above should be avoided.

　　Shen Weimin, deputy director of the Shanghai Quality and Technical Supervision Bureau, said that they will further strengthen the supervision and inspection of lighting products and "bathroom heater" products, urge companies to fulfill their quality responsibilities and ensure product quality and safety. At present, the Shanghai Product Quality and Safety Assessment Research Center has also launched relevant risk monitoring projects.

　　Kind tips

　　What blue light is the most harmful

　　Related studies have shown that different wavelengths of blue light have different harmful effects on human eyes. Blue light between 435 nanometers and 440 nanometers has the greatest harmful effect on eyes, and this effect gradually decreases with the increase or decrease of wavelength. In LED light sources , since most light sources emit white light through a mixture of blue light LED chips and yellow phosphors, the peak of the spectrum energy is just in the blue light band, so the proportion of blue light energy is naturally high.

　　In our daily life, there are many light sources that can emit blue light. In addition to bathroom heaters, flat-panel displays, LED neon lights, fluorescent lights, LCD displays, iPads, large-screen mobile phones, etc. all have background light sources. The light sources excited by powerful electron flows contain abnormal high-energy short-wave blue light, which will affect children's retinas and should be avoided from long-term direct viewing.

　　How to prevent the harm of LED blue light

　　To prevent the harm of LED blue light, the most important thing is to avoid direct viewing of the light source surface for a long time. For infants and the elderly who have weak protection awareness at home, measures should be taken to prevent the light source from directly shining into the eyes. In addition, generally speaking, the proportion of blue light in warm-toned LEDs is less than that in cool-toned LEDs, and the surface brightness of LED lamps with diffuser covers is lower than that of LED lamps without covers or with transparent covers. When consumers purchase LED lighting products, they should pay attention to the color tone and surface brightness of the products.

　　Who should pay attention to the hazards of LED blue light

　　There are three types of people who should be cautious when using LED lighting. The first type is children with delicate eyes. The lens of infants and young children is clearer and cannot filter blue light. Children have the nature of chasing light. Long-term exposure to large amounts of blue light may cause phototoxic damage to the retina of infants. Severe cases may even cause retinal holes and blindness. The second type is diabetics. After more than ten years of development, diabetes has retinal lesions, and the retinal tolerance to light damage has greatly decreased. In addition, many drugs in life are photosensitive. After taking the drugs, the damage of LED blue light may be more obvious. Finally, it is not advisable to use LED lights at night. Long-term use will affect sleep and cause biological clock disorders, thereby reducing people's immunity.