Laser Class 1
Lasers of laser class 1 do not have a potential hazard when used in a foreseeable manner, even in interaction with optical devices such as magnifying glasses or microscopes. Lasers of laser class 1 must be protected against manipulation. Industrial laser systems are usually shielded in such a way that no radiation greater than that of laser class 1 occurs outside the shielding. This is important, as laser radiation in the non-visible range is normally used here.
Laser Class 1M
Accessible laser rays in a spectral range from 302,5 and 4000 nm, proceeding divergent and widened are defined as Laser Class 1M. The complete ray is limited to a power of .5 Watt, the defined limit value of Laser Class 3B.
In the spectral range of 400-1400 nm the ray is naturally by the pupil, and merely a part of the ray will penetrate the inner eye, which will not go pass the level of Laser Class 1.
A hazard potential arises when the class 1M laser beam is viewed through an optical instrument such as a microscope or binoculars. In this case, corrective glasses should not be seen as a hazardous instrument, as they merely establish the correct field of vision for the eye.
The manufacturer must specify which optical instruments pose a hazard potential with a class 1M laser beam.
Laser Class 1C
With the revision of the norm, published in July 2015, this class has been defined for devices which are intended for the contact with a target object, such as the skin.
This class holds lasers which are used for cosmetical applications, like hair removal, skin tightening, acne treatment or tattoo removal. The class is also applicable for laser devices intended for the use at home. The passing of the energy values of Laser Class 1 has to be prevented. This is normally solved with the use of contact switches, which are designed to prevent human errors and the potential exposure passing the limit values of Laser Class 1.
Laser Class 2
Lasers within the definition of Laser Class 2 exclusively emit in the visible part of the spectral range, which is, defined by law, from 400-700 nm. The power is limited to 1 mW. A direct hit of the laser ray to the eye, even trough an optical instrument may lead to dazzling, but not to an irreversible damage. Still the intended look into the laser ray should be avoided.
Laser Class 2M
Just as Laser Class 2, the lasers classified as Laser Class 2M are within the, defined by law, visible spectral range of 400-700 nm. The ray is either widened of divergent.
The power of the complete ray is limited to .5 W, similar to the limit value of Laser Class 3B. Within the spectral range of 400-1400 nm, the ray is naturally absorbed by the pupil, and merely a fraction of the ray, below the limit value, defined by Laser Class 1 can penetrate the inner eye.
A potential hazard will only occur, should the ray be observed through an optical instrument.
Laser Class 3R
Lasers defined as Laser Class 3R are similar to lasers defined as Laser Class 2, with a 5 times higher power (400-700 nm; 5 mW). Outside the visible spectral range, the value of 5 times the value limit of Laser Class 1 must not be exceeded, unless widened, by the laser ray. A direct exposure of the eye is to be avoided. Lasers defined as Laser Class 3R are mostly used as show lasers.
Laser Class 3B
Lasers defined as Laser Class 3B have their energy value limit at 0,5 W in continuous wave mode. The observation of the incoming laser ray through a diffuse reflection (p.e. a non-reflecting surface) will not cause damage to the eye. The norm defines the minimum distance from the point of impact as 13 cm and the maximum observation time as 10 seconds.
The direct look into the source of the radiation may lead to irreversible eye damage. Therefore, the norm demands the use of a laser safety google, certified by DIN EN 207.
Laser Class 4
Every laser not classified into the previously named Laser Classes, is classified as Laser Class 4. Ray and also the reflection may cause irreversible damage to eyes and skin.
A laser safety goggle, certified after the norm DIN EN 207 has to be worn. Furthermore, the wearing of laser protective clothing is highly advised.
Lasers classified as Laser Class 4 may cause combustion and explosions, therefore, the necessary prevention to ensure the safety must be executed.