What is the basis for laser safety level classification?

Laser safety level classification is based on the mechanism of harm to human tissue and the degree of damage caused by laser products. 

The International Electrotechnical Commission standard (IEC 60825-1) divides laser products into the following 7 levels: 1, 1M, 2, 2M, 3R, 3B, 4. 

Among them, Class 1 is safe in the device, and the beam is usually completely enclosed, such as the laser in the CD player. 

Class 1M is safe in the device, but it will be dangerous after focusing through a magnifier or microscope. 

Class 2 is safe under normal use conditions, with a wavelength of 400-700nm visible light, and the eye's blink reflex can avoid damage. The power is usually less than 1mW, like a laser pointer. 

Class 2M is safe in the device, but it is dangerous to focus through a magnifier or microscope. 

Class 3R usually has a power of 5mW, and there is a small risk of eye damage during the blink reflex time. Staring for a few seconds will cause immediate damage to the retina.

 Class 3B will cause immediate damage to the eyes when exposed to laser radiation. 

Class 4 lasers can burn the skin, and scattered lasers may also cause damage to the eyes and skin, and may also cause fires or explosions. Many industrial and scientific lasers belong to this class.

The U.S. Food and Drug Administration (FDA) standard divides laser equipment into six levels, namely Class Ⅰ, Class Ⅱa, Class Ⅱ, Class Ⅲa, Class Ⅲb and Class Ⅳ. For Class Ⅰ, the laser radiation is not considered harmful; for Class Ⅳ, the laser radiation is harmful to the skin and eyes, whether direct or scattered.

Laser products of different levels have different degrees of harm. In actual production, laser products that may cause harm to the human body should be affixed with warning labels with laser hazard level classification. When using laser products, be sure to understand their safety levels to avoid harm.