I should restate what I said earlier - LEDs are covered under IEC 825, but the typical display LED falls so far below the Maximum Permissible Exposure levels as to be exempt (see Scope of IEC 825).
Paul O'S. -----Original Message----- From: geor...@lexmark.com [mailto:geor...@lexmark.com] Sent: Thursday, October 05, 2000 1:49 PM To: emc-p...@majordomo.ieee.org Cc: kathy....@eng.sun.com Subject: When is an LED a Laser? Kathy, I am no expert on IEC 60825, but may help a little. The standard is intended to prevent human exposure to light energy within specified wavelengths. It initially focused only on laser safety, because lasers represent a beam of focused energy, i.e. more uW per area. An LED is not a laser, but merely a light source. When this light is collimated and concentrated into a single beam, then it is a "laser". LEDs were added to the scope of IEC 60825 to ensure that the output of any LEDs (laser or not) would be within acceptable exposure limits. In general, common LEDs used for operator panel indicators distribute their light energy over a roughly hemi-spherical surface, although not equally. In most cases, there is insufficient energy in any vector to cause an exposure problem. George ---------------------- Forwarded by George Alspaugh/Lex/Lexmark on 10/05/2000 01:31 PM --------------------------- kathy.toy%eng.sun....@interlock.lexmark.com on 10/05/2000 01:08:52 PM Please respond to kathy.toy%eng.sun....@interlock.lexmark.com To: emc-pstc%majordomo.ieee....@interlock.lexmark.com cc: kathy.toy%eng.sun....@interlock.lexmark.com (bcc: George Alspaugh/Lex/Lexmark) Subject: When is an LED a Laser? Hi: Our design engineers are using LED more often and have been asked if the LED are approved by IEC 825. My question: When is an LED a Laser? In other words, at what power level does an LED become required to meet the IEC 825 standard? Are there industry limits for specific LEDs? It seems that in the past LEDs were basicly ignored except for color issues. What is the current thought or rule on this issue? Thanks in advance, kt _/_/_/ _/ _/ _/ _/ Kathy Toy _/ _/ _/ _/_/ _/ Safety Compliance Engineer _/_/_/ _/ _/ _/ _/ _/ Office/Voice Mail:(650)786-3210 _/ _/ _/ _/ _/_/ Dept. FAX: (650)786-3723 _/_/_/ _/_/_/ _/ _/ Email:kathy....@eng.sun.com M I C R O S Y S T E M S ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
