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Does The Blue Light Of LED Lights Really Damage Eyes?

Edit:Shaoxing Xinshan Science Technology Co.,Ltd   Date:Jul 03, 2017

Does the blue light of LED lights really damage eyes?

LED lamp is after the incandescent lamp, fluorescent lamp and energy-saving lamp of a new type of light source, high luminous efficiency, but lots of people with its luminous principle and spectral characteristics do not understand, hard to avoid can worry about it will light damage to the eyes.

Three colors of leds

From the spectrum, LED light is very different from traditional incandescent and fluorescent bulbs, and the so-called "spectrum" means that the light emitted by an object should have a "rainbow".

Traditional incandescent lamps and fluorescent bulbs have the same red, orange, green, blue and violet colors as sunlight.

However, generally LED light only has "RGB" of these 3 colors, where R is red, which means red; G means green, green light; And B means blue, which is blue light.

Leds in these three colors are the most important and basic of the "blue leds" between 400nm and 500nm.

The particularity of blue light

Where is the blue light?

Look at this "rainbow" picture. From left to right, it turns out to be uv, visible and infrared. The wavelength range of visible light is between 400 nanometers and 700 nanometers, and the wavelength range from 400 nanometers to 500 nm is blue, so this band is called blue light.

The basic unit of light is called a photon. The wavelength of the photon is inversely proportional to the frequency, and the wavelength of the blue light is short, so the frequency is high. According to Albert Einstein and Max Planck's formula of photon energy, we can know the photon energy is equal to the product of the Planck constant and the frequency of the photon, so blue photon energy is better than red light and green light, which we can use blue to "stimulate" out of the other colors of light, such as the yellow light can be blue "stimulate".

Blue-ray LED technology won the Nobel Prize for physics

The technology was developed in 1998, and the technology won the Nobel Prize for physics in 2014. It looks like the big blue leds are packaged together by GaN chips and yttrium aluminum garnet (YAG). GaN chips emit blue light, wavelength lambda equals 465nm, and wavelength bandwidth is about 30 nm.

How do white leds emit white light?

So how did the white leds that house the household produce white light? It has been said in the paper that the energy of the blue light photon is high, so it can be used to excite fluorescence. General with a blue LED the blu-ray on yellow light produces in the fluorescent powder (similar to the principle of fluorescent lamp, fluorescent lamp light is ultraviolet light in fluorescent lamp tube wall from phosphor powder on). Yellow light is blue light stimulated, together they shot out from the inside of the LED, we saw the white light, feeling as if in fact it's just a blue and yellow colors mixed together compound light.

For example, blue light is "mother" and yellow light is "son", and the two groups form the "white light" single parent family.

Because of this principle, so a lot of manufacturers in order to improve the brightness of white LED, directly increase the intensity of the blue light, yellow light, that may increase, and finally form the brightness of the white light is increased, but this will cause we will be in this paper to explain the "excessive" blu-ray.

The actual measurement of LED light spectrum


This shows the white LED, but in fact its spectrum contains a strong element of blue light.

Blue light affects the retina

So, since blue light is white LED's "mother", so what does the eye feel to blue light?

The tissue that is used to receive light in the eye is called the retina, and if the 400 to 500 nm in the light source is too bright, eye contact with the light source for a long time may cause photochemical damage to the retina. This damage is mainly divided into two categories: blue light directly with the vision of the photoreceptor cells reaction generated by the visual pigments, as well as blue and retinal pigment epithelial cells in the fat brown reaction caused by injury. These photochemical reactions produce a large number of free radicals that are cytotoxic and disrupt the normal growth and work of retinal cells.

We can also look at the dangers of blue light in a different way. Why can't a person's eyes accept the "excessive blue light" from a blue-ray LED? Because human is in the solar system evolved, according to the blackbody radiation Wayne displacement law, we can through the sun's surface temperature, calculate the center of the sun at about 550 nm wavelength, and blue leds center wavelength is 465 nm, away from the sun at the center of the wavelength, so from an evolutionary perspective, we cannot accept "excess" human eyes are blue.

The detection standard of LED blue light in life

Generally speaking, the product that formal manufacturer passes national quality inspection goes to market, do not have the hidden danger of blue ray overdose. But some manufacturers of LED lights do not pay attention to the intensity of the blue light. The blue light in the LED lamps they produce is "excessive" and there is a blue ray radiation damage to the eyes.

Life, there are many can emit blue light source -- bath bully, flat-panel displays, LED neon, fluorescent, LCD monitor, tablet, phone, etc are background light source, they contain short wave blue light. If the blue light is "excessive", it will affect the retina, so avoid looking at the light source with your eyes, and keep your eyes closed for about 20 to 30 minutes every 20 to 30 minutes.

If you're worried about buying LED lights or other electric equipment has the problem of "excessive" blu-ray, can according to the law of the People's Republic of China national standard GB/T 20145-2006 / CIE S/E: 20145, 2002 (the lamp and the light of the lamp system, security), to determine the blue leds is excessive, 

the standard blu-ray are given in the specific space Angle of upper limit of the luminous flux.

However, it is a complex problem to judge the overdose of LED blue light for the LED lights sold in the market. For example, this LED lamp, which is the "voltage and frequency" that is released from it, can't calculate whether the blue light is too much, because the voltage and frequency are electrical indicators, and blue light is an optical indicator. And its claim to "flux" is an optical indicator, but it is only the total flux of white light instead of blue light flux, so the average consumer is hard to figure out whether this light blue too much.