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From: dave@onfcanim.UUCP
Newsgroups: sci.electronics
Subject: Re: Bar-code Scanners: Are they safe?
Message-ID: <15455@onfcanim.UUCP>
Date: Thu, 5-Nov-87 10:58:54 EST
Article-I.D.: onfcanim.15455
Posted: Thu Nov  5 10:58:54 1987
Date-Received: Sat, 7-Nov-87 15:53:16 EST
References: <4814@oberon.USC.EDU> <244@enprt.Wichita.NCR.COM>
Reply-To: dave@onfcanim.UUCP (Dave Martindale)
Organization: National Film Board / Office national du film, Montreal
Lines: 13
Keywords: laser, bar-code, scanner

The lasers used in barcode scanners are almost certainly under 1mW in
beam power, which makes them class II.

A class II laser is considered no more dangerous than looking at the sun,
or other very bright light source (quartz-halogen lamp, carbon arc).
Your natural reaction to such a bright light, if it enters your eye, is
to blink, and the light intensity is such that no damage is done in the
time it takes to blink.  The only way to damage your eye is to deliberately
look at the light source instead of blinking.

In fact, a barcode scanner could use a much more powerful laser than 1mW
and still be safe as long as it was scanning, since no matter where your
eye is it cannot receive the beam for more than a very short period.