The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation. Lasers differ from other sources of light because they emit light coherently. This kind of device is used in different applications. The great variety of wavelengths, pulse energies and characteristics of lasers and laser systems that include, and applications and ways of use of these systems, make it essential for the purposes of security, group them into categories, or classes of danger. The classification of a laser is based on the concept of accessible emission limits (AEL) that are defined for each laser class, which describes the levels of radiation emerging from a laser system, the evaluation of which allows the placement of the device to the appropriate category of risk. The determination of the AEL must be performed under the most unfavorable conditions for safety purposes.
Lasers are divided into 5 classes: 1, 2, 3R, 3B and 4, according to their ability to produce damage in exposed people.
A Class 1 laser is safe under all conditions of normal use. This means the maximum permissible exposure (MPE) cannot be exceeded when viewing a laser with the naked eye or with the aid of typical magnifying optics.
Used in: Laser printers, CD players, DVD players
A Class 1M laser is safe for all conditions of use except when passed through magnifying optics such as microscopes and telescopes.
A Class 2 laser is safe because the blink reflex will limit the exposure to no more than 0.25 seconds. It only applies to visible-light lasers (400–700 nm). Class-2 lasers are limited to 1 mW continuous wave, or more if the emission time is less than 0.25 seconds or if the light is not spatially coherent. Intentional suppression of the blink reflex could lead to eye injury. Many laser pointers and measuring instruments are class 2.
Class 2M/ 2A:
A Class 2M laser is safe because of the blink reflex if not viewed through optical instruments. As with class 1M, this applies to laser beams with a large diameter or large divergence, for which the amount of light passing through the pupil cannot exceed the limits for class 2.
A Class 3R laser is considered safe if handled carefully, with restricted beam viewing. With a class 3R laser, the MPE can be exceeded, but with a low risk of injury. Visible continuous lasers in Class 3R are limited to 5 mW. For other wavelengths and for pulsed lasers, other limits apply.
lA Class 3B laser is hazardous if the eye is exposed directly, but diffuse reflections such as those from paper or other matte surfaces are not harmful. The AEL for continuous lasers in the wavelength range from 315 nm to far infrared is 0.5 W. For pulsed lasers between 400 and 700 nm, the limit is 30 mJ. Other limits apply to other wavelengths and to ultrashort pulsed lasers. Protective eyewear is typically required where direct viewing of a class 3B laser beam may occur. Class-3B lasers must be equipped with a key switch and a safety interlock. Class 3B lasers are used inside CD and DVD writers, although the writer unit itself is class 1 because the laser light cannot leave the unit.
Lasers in this class have output powers of more than 500 mW in the beam and may cause severe, permanent damage to eye or skin without being magnified by optics of eye or instrumentation. Diffuse reflections of the laser beam can be hazardous to skin or eye within the Nominal Hazard Zone. Many industrial, scientific, military and medical lasers are in this category.
Used in: Hi-Power Laser pointers
Alternative to laser pointing system, as regards the positioning, it is the power LED. The LED is a monochromatic light source, which emits no harmful radiation and keeps a luminous efficiency constant over time. The LED pointers have been designed and built for the alignment and the positioning of materials on sewing and pressing machines as well as for infinite other use. They can therefore be installed wherever maximum precision and productivity are needed on a industrial level, up to 80 cm height. The absolute resiliance to shock and vibrations including resistance to dust and fine particles makes this range fully suitable to industrial environments. In the LED pointing and/or positioning system LED lightcan be focused changing the spyglass position. C.C.E.A. invented this system for the use in textile field for positioning of materials. LED can be used even on reflective surfaces, where laser may affect worker's phisical integrity. In compliance with international standards on low voltage C.C.E.A. lamps can be plugged directly to 12 - 24 volts. C.C.E.A. uses the latest Power LED that ensure a minimum of 50,000 hours, up to 70,000 hours of life. Consequently, they do not require any maintenance and replacement, with significant savings of money and time. The LED lamps C.C.E.A. can operate continuously 24 hours a day for 6 years without replacement or maintenance and guarantee for their entire life a constant lighting in time with the same luminous efficiency. The Power LED technology guarantees at least 50% energy saving compared to conventional lighting. The LED pointers provide a beam of light of any color.