Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!mailrus!ncar!boulder!ccncsu!ncr-fc!mikemc From: mikemc@mustang.ncr-fc.FtCollins.NCR.com (Mike McManus) Newsgroups: sci.electronics Subject: Re: Are checkout-counter lasers hazardous? Message-ID: Date: 9 Jan 90 17:21:15 GMT References: <189@bucsb.UUCP> <446@sierra.stanford.edu> Sender: news@ncr-fc.FtCollins.NCR.COM Organization: NCR Microelectronic Products, Ft. Collins, CO Lines: 32 In-reply-to: siegman@sierra.Stanford.EDU's message of 9 Jan 90 05:17:28 GMT In article <446@sierra.stanford.edu> siegman@sierra.Stanford.EDU (Anthony E. Siegman) writes: > In addition, a few milliwatt cw visible laser is really not that > hazardous. It certainly can't burn skin or the outer surface of an > eye, and even if optimally focused within an eye on a continuous basis > my guess is it would still not do real physical damage (burning or > phase transformation) to the retina. In addition, your natural blink > reflex will close the eyelid very rapidly. And, the actual output > beam from a supermarket scanner unit may be more in the 10 to 100 > microwatt range. Also, the laser scanners found in check-out lanes have beams which are being rapidly projected across the surface of the package (or in this case, your face :-) by a series of spinning mirrors. The amount of time that the laser is focused on any one spot, most notably your eyes, is minimal. The same thing is true, incidently, with those hand-held laser "guns" that some retail stores use. A guy I used to work with tried shooting one in his eyes ones, "just to see what it would do..." He said that it was a sensation similar to having a flash bulb go off in your eyes, but recovered after several minutes, and there was no permanent damage (burns on the eye or retina). -- Disclaimer: All spelling and/or grammer in this document are guaranteed to be correct; any exseptions is the is wurk uv intter-net deemuns. Mike McManus (mikemc@ncr-fc.FtCollins.ncr.com) NCR Microelectronics 2001 Danfield Ct. mikemc@ncr-fc@ncr-sd.sandiego.ncr.com, or Ft. Collins, Colorado mikemc@ncr-fc@ccncsu.colostate.edu (303) 223-5100 Ext. 360 (they're ugly, but they work!)