Guided reading: In the imaging visual channel, the blue light of LED lamps may cause retinal visual harm. On the non imaging channel, the blue light of the LED luminaire may have an effect on circadian rhythms.
The light enters the human eye with two visual channels, one is the imaging visual channel (the real line in Figure 1), the other is the biological clock and the time of the non-imaging channel (the dotted line in Figure 1). In the imaging visual channel, the blue light of the LED luminaire may cause visual damage to the retina. On the non imaging channel, the blue light of the LED luminaire may have an effect on circadian rhythms.
The wavelength of Blu-ray LED is around 450nm and coincides with the rhythm of the body's Chen (circadian rhythm/Circadian clock), which has a strong ability to secrete melatonin inhibitors. A decrease in melatonin can cause excitement and no sleep. This will affect the human immune system.
Fig. 2 is a typical 5500K rich blue LED light emitting spectrum, depicting the maximum spectral energy wavelength in a rough line in 460nm region, coincides with the human body on the secretion of melatonin inhibitor spectral curve, so that the long-term concomitant will affect the human body normal sunrise and sunset and the circadian rhythm, so limit the blue light energy below 500nm, reduce the impact on the circadian rhythm of people is very important.
In order to avoid the use of rich blue LED lamps on human health may be adversely affected, indoor LED lighting color temperature should not exceed 4000K.
The effect of blue light on the circadian rhythm of the human body is usually included in the product standard Performance index.
Spectral sensitivity curve of rich blue led Baiguang spectrum and melatonin inhibitor
The coincidence indicates that the night's rich blue led white is unfavorable.
How does the blue light of LED lamps form?
In order to get stable, reliable and simple white light, the most commonly used method is to use the blue light led chip to stimulate the yellow phosphor. LED radiation out of the wavelength of about 450nm blu ray, blue light in this process is divided into two parts, a part of the Blu-ray excitation phosphor emitting the wavelength of 570nm around the yellow-green, the other part of the blue light transmission and excitation phosphor produced by the yellow-green lights mixed to produce white,
Color temperature is the most common index of spectral quality of light source. According to the proportion and composition of the phosphor, white LED can provide color temperature in the 2700 between the cold white, neutral, warm white color range of the whole series.
The color of the light emitted by the light source and the blackbody (a completely radiant body, black) at a temperature at a time, the blackbody temperature is called the light color. In blackbody radiation, with different temperatures, the color of the emitting light varies, and when the black body presents a gradual process from red-orange-yellow-white-blue-bluish white-the process of color temperature from low to high. The higher the "blackbody" temperature, the more blue components in the spectrum, and the less red. For example, incandescent light color is warm white, its color temperature is 2700K, and the color of daylight color fluorescent lamp is 6000K.
The change of sunlight in nature during the daytime is just the color change of the luminous body temperature. Morning and Evening sun Light 2000 (Warm white), 8:00 solar 4000K (white), midday sun Light 5000 (daylight).
"Warm Light" color temperature is low, and "cold" color temperature is relatively high. When the color temperature increased, the proportion of Blu ray radiation increased and the content of blue light increased. At the same time, brightness also affects the ratio of blue light.
Usually, 2700 color temperature is called low color temperature. The color temperature of 5000 is called high temperature. High color temperature of white light due to high blue content, but also known as "Rich blue" white.
What is the blue light hazard of LED lamps?
Because the LED light source has a small luminous area, high brightness characteristics, and blue light than other optical wavelength is shorter, so there is greater radiation energy, the possible radiation hazards than other colors of the light is larger. Blue-ray Hazard refers to the hazard of the 400 Blu-ray band in the light source, if an LED lamp is too bright, the eye can cause photochemical damage of the retina after long time looking directly at the luminous body. The extent of blue-ray damage depends on the amount of blue light received by the human eye.
Depending on the maximum exposure time for each injury that does not exceed the exposure limit, the hazard rating is divided into the four levels represented in the following table:
There are several provisions as follows:
(1) The lamp does not use the blue light harm more than RG2 led source.
(2) indoor LED lighting blue light hazard is not RG1.
(3) for children with removable lamps and electrical outlets installed night light, should not exceed RG1.
(4) The use of RG0 (hazard-free) LED lamps is recommended for special groups (such as people with diabetes and photosensitive drugs) or may be in a position to gaze directly at LED lamps (e.g. infants).
As a result, the blue light hazard is considered when the Blu-ray radiance reaches the standard RG2 or above, considering that the human eye is in the shorter time or the instantaneous damage to the human eye.
The assessment of Blu-ray Hazard is usually included in the Product standard Safety index.