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Chinese Specialist About Danger of Blue LEDs

Many consumers are shying away from LED lighting due to potential harm blue LED bulbs can have on the retina of the eye. The media has even confused blue lights emitted from blue-ray and blue LED light. So what exactly are blue LEDs then?

The risk that blue light poses to the eye depends on the amount of exposure. LEDs and CFL bulbs of the same color temperature show very little difference in safety.

Recently during the International Solid-State Lighting Applied Technology Forum in Shanghai, China, attending experts discussed the harmful effects of blue LEDs on eyes. “White LED light is created using a phosphor material to convert monochromatic light from a blue LED,”said Zhang Shanduan, Deputy Head of Electric Light graduate school at Fudan University. “Blue light hazard refers to a wavelength in the blue light spectrum of 400-500 nanometers or higher. Looking directly at blue light for an extended period of time can cause retinal damage. Blue light hazard level depends on exposure to blue light.”

“The LED fixtures in the market currently use “blue chip and yellow phosphor” which gives the LED lighting a higher proportion of blue light. However this does not mean that LED is any more harmful for the eye than other light fixtures,” said Zhang. In their light comparison experiments, safety between LEDs and CFLs of the same color were about the same.

Color temperature is a leading indicator in light assessment. Often warmer lights have a lower color temperature and cool lights have a higher color temperature. A rise in color temperature increases the proportion of blue radiation and blue light. Blue light also goes with increased luminosity. In general, LED lamps are as safe as fluorescent lamps of the same color temperature, as long as its luminosity is less than three times that of the fluorescent lamp. 

Aside from bulbs and cell phones , computer monitors also use blue LEDs. In response to the harm blue LEDs can cause to the eyes, Shu Anqi, Head of the China National Lighting Fitting Quality Supervision Testing Center (CLTC) in Shanghai noted that staring at any form of light, such as the sun, will obviously cause harm to one’s eyes.

The International Electrotechnical Commission (IEC) released a new international specification which is only used as a reference in China, making the safety of products worrisome. International blue light photobiological safety standards have been established according to the light's brightness, and safety levels have been set for possible blue light damage, said Mou Tongshen, Optical Engineering professor of Zhejiang University Department. For example, light without any blue light hazards are level 0, a light with minor hazards are placed in first category and high hazard lights in second category. Currently most standard LEDs are in the level 0 and first category. If a second category light is used, there will be a warning label applied to warn users not to stare directly into the light.

Shanghai ear nose and throat clinic director Sun Xinghuai said that for those with special lighting safety needs such as infants, diabetes patients of more than 10 years, some high blood pressure sufferers, and patients on light sensitive medication, using level 0 LEDs are best.

The strength of the blue light can effect one’s biological clock. Blue light can increase our body’s cortisol secretion making us more energetic. However at night, it’s best not to use a light that uses too much blue light. The best light to pick is a warm colored light, said professor Zhou Taiming, the author of “General LED Lighting and Blue Light.”

Zhang advices consumers to choose light fixtures with a diffusion shell or diffusion plate, one in which the chip is not directly visible, and where the luminosity is not overtly concentrated when purchasing indoor LED lighting.

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Chinese Experts on Danger of Blue LEDs
Topics: Lighting