Newsgroups: sfnet.harrastus.elektroniikka
Subject: Re: Laser =?iso-8859-1?Q?kynist=E4?=
References: <[email protected]> 
	<[email protected]>
Timo Taskinen  writes:
> Mutta ainakin minulla on Suomesta ostettu 3 milliwatin (meni rikki
> parissa kuukaudessa) ja sitten ostin Teneriffalta 5 milliwatin
> laserin joka on kest{nyt jo puolisen vuotta todella hienosti.

No tuohon rikkimenemisherkkyyteen tuo laserin teho ei vaikuta.
Taisi vaan olla huono kappale tai huonolaatuinen tuote tuo Suomesta
ostamasi.

> Mitenk{ muuten nuo luokitukset menev{t? Eli "laser class" jutut?

As posted by the Center for Devices and Radiological Health (CDRH)
regulation 21 CFR 1040.10 and 21 CFR 1040.11, the standard
classification for lasers are as follows: 

Class I laser product

No known biological hazard. The light is shielded from any possible
viewing by a person and the laser system is interlocked to prevent the
laser from being on when exposed. (large laser printers such as the
DEC LPS-40 has a 10mW HeNe driving it which is a Class IIIb laser, but
the printer is interlocked so as to prevent any contact with the
exposed laser beam, hence the device produces no known biological
hazard, even though the actual laser is Class IIIb. This would also
apply to CD players and small laser printers, as they are Class I
devices). 

Class II laser products

Power up to 1 milliwatt. These lasers are not considered a optically
dangerous device as the eye reflex will prevent any occular
damage. (I.E. when the eye is hit with a bright light, the eye lid
will automatically blink or the person will turn thier head so as to
remove the bright light. This is called the reflex action or
time. Class II lasers won't cause eye damage in this time
period. Still, one wouldn't want to look at it for an extended period
of time.) Caution labels (yellow) should be placed on the laser
equipment. No known skin exposure hazard exist and no fire hazard
exist. 

Class IIIa laser products

Power output between 1 milliwatt and 5 milliwatt. These lasers can
produce spot blindness under the right conditions and other possible
eye injuries. Products that have a Class IIIa laser should have a
laser emission indicator to tell when the laser is in operation. They
should also have a Danger label and output aperature label attatched
to the laser and/or equipment. A key operated power switch SHOULD be
used to prevent unauthorized use. No known skin hazard of fire hazard
exist. 

Class IIIb laser products

Power output from 5 milliwatts to 500 milliwatts. These lasers are
considered a definate eye hazard, particularly at the higher power
levels, which WILL cause eye damage. These lasers MUST have a key
switch to prevent unathorized use, a laser emission indicator, a 3 to
5 second time delay after power is applied to allow the operator to
move away from the beam path and a mechanical shutter to turn the beam
off during use. Skin may be burned at the higher levels of power
output as well as the flash point of some materials which could catch
fire. (I have seen 250mW argons set a piece of red paper on fire in
less than 2 seconds exposure time !) A red DANGER label and aperature
label MUST be affixed to the laser. 

Class IV laser products

Power output >500 milliwatts. These CAN and WILL cause eye damage. The
Class IV range CAN and WILL cause materials to burn on contact as well
as skin and clothing to burn. These laser systems MUST have: 

A key lockout switch to prevent unauthorized use Inter-locks to
prevent the system from being used with the protective covers off
Emission indicators to show that the laser is in use Mechanical
shutters to block the beam Red DANGER labels and aperature labels
affixed to the laser 

The reflected beam should be considered as dangerous as the primary
beam. (again, I have seen a 1,000 watt CO2 laser blast a hole through
a piece of steel, so imagine what it would do to your eye !) 

> Kannattaako ennemmin katsoa tehoa ja aaltopituutta?
> Eli kun minulla on "Class IIIa laser product, Wavelength 630~680nM,
> Max output < 5mW"

Aallonpituutta kannattaa katsoa. Silm� on melkoisen ep�herkk�
tuolla 680 nm aleella, joten valitsemalla samantehoisen laserin joka on
silm�lle herkemm�ll� aluella saa paljon kirkkaammalle n�ytt�v�n
pisteen. Esimerkkin� 1 mW HeNe (630 nm) laseri n�ytt�� suunnilleen yht�
kirkkaalle kuin noin 3 mW 680 nm puolijohdelaseri. 1 mW tehoinen
vihre� kaseri n�ytt�isi taas monta kertaa kirkkaammalle kuin nuo
edell� mainitut, koska silm� on t�lle aluelle herkempi kuin
punaiselle.

> Ent{s mit{ tarkoittaa seuraava teksti laserissani:
> "Complies with: 21CFR 1040.10 & 1040.11"
> Onko kyseess{ jokin turvam{{r{ys standardi?

T�ytt�� USA:laisen Center for Devices and Radiological Health (CDRH) 
antaman kyseisen lasereita koskevan turvam��r�yksen.

---
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web pages at http://www.hut.fi/Misc/Electronics/