Kyaw: It may help to see IEC Technical Report TR 60825-10 "Safety of laser products Part 10: Application guidelines and explanatory notes to IEC 60825-1," Sections 9 Intrabeam Viewing, and 10, Extended Source Viewing.
Also see IEC Technical Report TR 60825-14 "Safety of laser products Part 14: A user's guide," which is a "guide" to 60825-1, and contain numerous worked calculation examples, etc. These were written as informative and educational texts to the normative parts of IEC 60825-1. William T. Sykes Lucent Technologies EH&S Product Safety/Conformance Manager Room 7B-516A 600-700 Mountain Avenue Murray Hill, NJ 07974-0636 (908)582-6937 From: [email protected] [mailto:[email protected]]On Behalf Of KYAW HTIN AUNG Sent: Thursday, June 08, 2006 12:22 PM To: EMC PSTC Subject: Laser safety AEL calculation - angular subtense and C6 Dear Good People Our product is a class II laser scanning engine. The original source of laser is from a laser diode. It passes through a lens and strikes two subtended mirrors before it goes out for scanning. According to IEC 60825-1, AEL limit is defined as C6x10-3W where C6 is based on angular subtense (alpha). If alpha is less than or equal to alpha min, C6 = 1. If alpha is between min and max, C6 is alpha/alpha min where alpha min is 1.5mrad. The debate right now is how to define alpha value to get C6. I was told to consider it is intrabeam viewing so that alpha is always min and C6=1. I have no objection that it is intrabeam viewing but I do not accept that alpha is always min for intrabeam viewing. In our case, I consider it is an enlarged source, not a point source. Enlarged source will create enlarged image at the retina of our eye. So alpha will be greater than min value of 1.5mrad and C6 will be greater than 1. Anybody can shed the light on this topic? Or any reference to a good info source? Thanks in advance Kyaw Send instant messages to your online friends http://uk.messenger.yahoo.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
