Ultraviolet light is an electromagnetic wave with wavelengths shorter than visible light and longer than X-rays. It is a kind of invisible light that lies outside the violet color in the spectrum, so it is called ultraviolet. Ultraviolet light is invisible to the human eye, but can cause sunburn on the skin.

There are three main types of ultraviolet light: UVA, UVB and UVC.

UVA has a wavelength range of 315-400 nanometers and can penetrate the atmosphere to reach the ground. It is the main cause of sunburn and skin aging.

UVB has a wavelength range of 280-315 nanometers, most of which is absorbed by the ozone layer and only some of which reaches the ground. It is the main cause of erythema and sunburn.

UVC has a wavelength range of 100-280 nanometers, almost all of which is absorbed by the ozone layer and hardly reaches the ground. It has a strong bactericidal effect, but can also cause skin and eye damage.

The main hazards of UV are:

Sunburn and skin cancer: Prolonged exposure to UV rays can lead to skin redness, blisters, skin darkening and skin cancer.

Skin aging and wrinkles: UVA can destroy collagen and elastin, accelerating skin aging and wrinkle formation.

Eye damage: Intense UV rays can damage the cornea and crystal of the eye, causing cataracts, vitritis and other eye diseases.

Immune system inhibition: UV rays can inhibit the body's immune function, reducing resistance.

Other hazards:UV is also thought to be related to melanosis, vitiligo and glaucoma.

The current led technology, can realize the production of led lamp beads of UVA, UVB, UVC three bands, but due to the high UVA light efficiency is more mature, use more. The other two bands are less applied.