According to the classification of the risk of the laser to the human body, the observation in the beam is used as a benchmark for the MPE (maximum possible effect ), which can be divided into one to four levels.
Class I: Low output laser (power less than 0.4mW), no matter what the conditions for the eyes and skin, will not exceed the MPE value, even after focusing through the optical system will not exceed the MPE value. The design can be secured without special management. Typical applications are CD players, CD-ROM equipment, geological exploration equipment and laboratory analytical instruments.
Class II: Low-output visible laser (power 0.4mW-1mW), the response time of a person closing the eye is 0.25 seconds, and the exposure calculated with this time cannot exceed the MPE value. Usually less than 1mW of laser, can cause dizziness can not be considered, with closed eyes to protect, can not be said to be completely safe, do not observe directly in the beam, do not use Class II laser directly to other people's eyes, avoid using Yuanyuan equipment to observe Class II laser. Typical applications such as classroom presentations, laser pointers, sighting devices and rangefinders.
Class III: Medium output laser, which can cause damage if it is directly injected into the eye. It is further classified into IIIA and IIIB for some safety reasons. Class IIIA is a continuous laser with visible light, and the output is 1-5mW. The energy density of the beam should not exceed 25W/m-m. Avoid using the Yuanwang equipment to observe the IIIA laser, which may increase the danger. Typical applications for the IIIA have many similarities to Class II, such as laser pointers, laser scanners, and more. Class III B is a continuous laser of 5-500 mW, which is dangerous to observe directly in the beam. However, the minimum irradiation distance is 13 cm, and the maximum irradiation time is less than ten seconds. Typical applications for IIIB lasers include spectrometry and entertainment lighting performances.
Class IV: High output continuous laser (greater than 500mW), higher than the third level, there is a danger of fire, and diffuse reflection is also dangerous. Typical applications are surgery, research, cutting, welding and micromachining. Safety measures for laser processing: Applications such as general home or office compact discs or laser printers are designed to prevent laser light from being emitted from the outside, ensuring safety. Other laser light does not emit a device that does not have an external energy.
If there is such a situation, it is necessary to refer to the following countermeasures.
(1) According to the level of the laser device, people with sufficient knowledge and knowledge about the safety or injury of the laser should guide the treatment.
(2) Laser production of three or more levels is performed by a person with appropriate safety education.
(3) The laser device in operation does not visit the optical path even if it does not emit laser light.
(4) The adjustment of the laser resonator, when the optical axis is lowered, the laser will suddenly emit. Always pay attention to the position of the eyes to deal with.
(5) When using a large-sized laser such as a CO2 laser that does not have an infrared light that cannot be seen by the eyes, people in the vicinity should pay special attention.
(6) When it is impossible to avoid reflected light or scattered light, protective glasses can be used when lasers of three or more levels are used.