the laser near the danger level

For these reasons, users should observe the following safety precautions: compliance with the operating manual for all safety precautions. Must be used with caution in the vicinity of the laser solvent. Only qualified personnel familiar with laser safety operations. Do not look directly at the laser light source or any reflective surface scattering from the laser beam, determined not to look down along the beam. Experimental settings remain at low altitude, to prevent inadvertently leaving the beam injected into the eye. To guard against accidental or reflected output beam irradiation, the operator should wear appropriate safety glasses specified wavelength of the laser. Avoid direct the laser, the beam intensity is easy to burn skin or ignite clothing. In a sealed room using a laser, if not controlled, the laser in a very long distance is still very parallel so there is still potentially dangerous. The laser beam within the danger zone warning signs affixed to remind all laser users and laser systems for all the laser near the danger level. Advise you that in the control room operation and limit the laser. The user is discussing the directivity of laser pointer  with the manager. The infrared  laser pointer  is relatively cheaper. Grade Ⅰ: This laser will not pose any known degree of injury. Class IA: This is a special level, means "not suitable for direct viewing with the eyes" of the laser, such as supermarkets use of laser scanner. The maximum limit for this level of laser power of 0.4 mW. Class II: refers to the low-power visible lasers, the transmit power level higher than I, but the radiated power does not exceed 1 mW. Defense of human response to strong light and automatically protect humans from harm. Class IIIA: refers to the low-power laser (continuous wave :1-5 mW), only within the beam, as the case would constitute a hazard. Most of the pen-shaped laser pointer belong to the class. Class IIIB: refers to the general power of lasers. Class IV: refers to high-power lasers (cw: 500 mW, pulse: 10 J/cm2 or the diffuse reflection limit), under any circumstances, whether direct or indirect observation is at risk, and may cause a fire or burn the skin. Class IV laser device must accept strict control. The infrared  laser pointer  will be used in many locations.
Present in the laser industry, laser safety rating four levels: Class I: low output laser (power less than 0.4mW), regardless of the conditions under which the eyes and skin, will not exceed the MPE value, even after focusing through the optical system will not exceed MPE values.