Laser Classes
class 1
A class 1 laser is safe under all conditions of normal
use. This means the maximum permissible exposure (MPE) cannot be exceeded. This
class includes high-power lasers within an enclosure that prevents exposure to
the radiation and that cannot be opened without shutting down the laser. The
maximum emission is also related to the pulse duration in the case of pulsed
lasers and the degree of spatial coherence.
class 1M
A Class 1M laser is safe for all conditions of use except
when passed through magnifying optics such as microscopes and telescopes. Class
1M lasers produce large-diameter beams, or beams that are divergent. The MPE
for a Class 1M laser cannot normally be exceeded unless focusing or imaging
optics are used to narrow the beam. If the beam is refocused, the hazard of Class
1M lasers may be increased and the product class may be changed. A laser can be
classified as Class 1M if the total output power is below class 3B but the
power that can pass through the pupil of the eye is within Class 1.
class 2
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 are class 2.
class 2M
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.
class 3R
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.
Laser diodes
PalmLaser and LaserCat are working with semiconductor
lasers - or better known as laser diodes.
Depending on the active region material, the wavelength
is different:
InGaAlP: 630 - 685 nm
GaAlAs: 780 - 820- 870 nm
GaAs: 904, 905 nm
These lasers are used for the laser-phototherapy.
Laser diodes are durable, robust and reliable.
We differentiate between pulsed lasers and cw-lasers
(cw = continuous wave).
A cw diodes which is only
switched on and off is not a real pulsed laser. From this there is a big
difference in the output power, as a real pulsed laser has a few Watt per
pulse.
class 3B
A Class 3B laser is hazardous if the eye is exposed
directly, but diffuse reflections such as from paper or other matte surfaces
are not harmful. Continuous lasers in the wavelength range from 315 nm to far
infrared are limited to 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
prescribed.
class 4
Class 4 lasers include all lasers
with beam power greater than class 3B. In addition to posing significant eye
hazards, with potentially devastating and permanent eye damage as a result of
direct beam viewing, diffuse reflections are also harmful to the eyes within
the distance called the Nominal Hazard Zone. Class 4 lasers are also able to
cut or burn skin. In addition, these lasers may ignite combustible materials,
and thus represent a fire risk. Class 4 lasers are usually taken for hair
removal, tattoo removal, surgery etc.
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