gmcintu...@packetengines.com writes: >Rick, <<snip>> >But they can also be reduced to such a small power output, 50 >mW that they should not be harmful.
Gary, For the most part your comments are relatively accurate. Some comments added: 1. Laser safety is covered in 21 CFR 1040.10 for the US. This is a regulation put in force and monitored by The Center For Devices and Radiological Health (CDRH), Department of Health and Human Services (DHHS), Food and Drug Administration (FDA). In Europe it is covered under EN 60825-1, -2, -3 etc. 2. There are 4 main classes and several sub-classes. Class I, Class II, Class IIa, Class IIIa, Class IIIb and Class IV. Each class has limits as to power level, frequency and duration. Measuring laser light to determine laser class is a complicated task requiring certain beam sizes (apertures) and the formulas include pulse width and repetition rate as well as other details. 3. In the case of a red helium-neon laser (632 nm) or a red visible laser diode (670 nm) a Class I laser system has a limit of 0.39 microwatts continuous laser light. Class IIa = 3.9 microwatts. Class II = 1 milliwatt. Class IIIa = 5 mW, Class IIIb = 500 mW. Class IV = above 500 mW. Each of these limits has a duration attached and it varies. There are other factors, but this is a good first pass estimation. 4. 50 mW can certainly be harmful depending on exposure duration. Whether damage is permanent or temporary again depends on energy level and duration. 5. Supermarket scanners are typically Class IIa laser products. Surveyors instruments are typically Class IIIa (if I recall correctly). The one catalog I saw that advertized these laser pointers had the Class III warning at the bottom of the page. I still think that I don't want to be surprised by a bright red light pointing in my eye when I don't know it's coming. This makes me uncomfortable with Class III pointers in the hands of kids playing tag. Regards, Scott s_doug...@ecrm.com --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
