They want the LED itself to be bright so it shines through the Light Pipe with good intensity. LED brightness is a relative thing. If your product is used in a relatively dark ambient room the indicators appear too bright (get out the black tape). But it if is installed in a very bright room, then you get complaints that the customer cannot read the indicators. You cannot win.
The LED in question is only rated 150mcd (millicandelas) which doesn’t seem very high to me. Is there a “Light Intensity” level in which you have to be concern about being too bright? I would like to just give Engineering a value and tell them to keep their LEDs below that level and you will have no problem. Thanks, The Other Brian From: Anthony Thomson [mailto:[email protected]] Sent: Monday, January 13, 2014 10:33 AM To: [email protected] Subject: Re: [PSES] LED Indicator Safety Hello Brian, It’s my experience that as the brightness of LED indicators increase, they become distracting and annoying way before they come anywhere near being hazardous. If your indicators are so bright as to even think they could be hazardous, I’d be asking myself why they’re so bright in the first instance. I have two pieces of equipment at home with small squares of black tape over stand-by (red) and power (blue) LEDs. Tell your engineers that it is OK to drive LEDs at less than 20mA! Regards, Tony ----- Original Message ----- From: Kunde, Brian Sent: 01/13/14 02:56 PM To: [email protected]<mailto:[email protected]> Subject: [PSES] LED Indicator Safety Greetings to all. I'm being asked by Engineering regarding the brightness of a Green LED Indicator they want to use on the front of an upcoming product. The LED is quite bright and is used with a Light Pipe which shows through the front panel. However, if you remove to front panel to perform a maintenance operation while the unit is still turned on (which is desired) you can see the LED. If you look directly at the LED it is bright and hurts to look at it for more than a second. However, you would have to deliberately look directly at it to receive the full brightness. At normal angles and distance the light causes no discomfort to look at it. The IEC/EN/UL/CSA 61010-1 safety standard only includes information about UV light. The EUT is classified as Laboratory Equipment. My Google research mentions the standard IEC 60825 and IEC 62471 and test method ANSI/IESNA RP-27. Would it be helpful to read these standards without having the test equipment to test it? For visible light such as this isn't there a simple test method such uses a basic light meter to determine if a hazard exists or not? Are LEDs classified by the manufacturer for their "Risk Group"? What Risk Group can I use and declare it not hazardous? Sorry for being such a NUBE on this topic. I know this topic has been discussed in the past but I was hoping new LIGHT might have been shined on it recently with all the new super bright LEDs on the market. Thanks in advance. The Other Brian ________________________________ LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. 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To post a message to the list, send your e-mail to <[email protected]<mailto:[email protected]>> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe)<http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> ________________________________ LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 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]>
