Firstly, there should be no UV and IR light in the spectral composition. Excessive long-term acceptance of ultraviolet rays, not only easy to cause keratitis, but also the lens, retina, choroid and other damage. Infrared Ray is very easy to absorb water, too much infrared ray through the human eye lens accumulation is absorbed by a large number of time, the lens will be denaturation, resulting in cataracts.
Second, the color temperature of light should be close to natural daylight. People live in natural light for a long time, the human eye is adaptable to natural light and good visual effect.
Third, the light is no frequency flash. Ordinary fluorescent lamp power supply frequency of 50 Hz, indicating that the glow of the dark 100 times per second, belonging to low frequency flash, will make the human eye regulating organ in a tense state of regulation, resulting in visual fatigue. If the frequency of luminescence is increased to hundreds of, tens of thousands of Hz or above-to become a high frequency, the human eye will not have a flash sensation; But the true flicker is the light emitted by the DC power supply or semiconductor solid-state light emitting diodes (such as LED light emitting diode) is called a frequency-free flash.