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Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
If one were to develop a device, based on laser tech, I presume there are standards for eye safety in the EU and US.
I need to use an invisible laser, technically it's classified as lllb while constant on, but it's modulated, and mechanically scanned around a room. So, what IR wavelengths, power outputs and duty cycles should I design for in anticipation of sending a final device off to be evaluated for some sort of certification?
my supplier cant do 808nm in large quatities frequently, but suggested changing to 780nm, suprise the 785nm turns up in a similar lidar! perhaps for human safety reasons? ive never used 780nm before, is it very dark to the un protected eye? is it less dangerous since its closer to visible red?
ill post my filter graph too.
IR filter plastic i dont think it ould pass much 780nm though...
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4059
Hi, a lot of laser mice use a 780nm VCSEL. uses about a quarter of the power as an LED and works better due to being a point source. Last time I checked these topped out at 0.5mW 1mA and burn out above that so they are pretty safe even if the control circuit goes bad.
The eyes response to >700nm is so low that the blink reflex essentially provides no protection. Standard irradiance MPE limits apply.
I have a tested and confirmed 4.2mW 785nm module I did some testing with a while back, I could see the spot on the wall a few meters away if it moved slowly in a dim room, but my wife could not. Direct eye shots (time limited for safety) produced no blink reflex.
Class 3B is a huge range (5.01mW to 499.9mW), what power were you actually planning on?
Ah, that's 3A, I'd see no issue there as long as you cover yourself in legal. Tons of products with 3A diodes running CW in open emission applications.
Yup, probably a warning label stating to not stare directly at the output is all that would be needed. Cat toys do similar and usually output about 4mW. Granted, at 780nm the blink reflex is greatly diminished, but I've yet to see any reports of eye damage from <4mW, and that's for CW.
Registered Member #3215
Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780
beware that pulsed operation will drive the laser diode into pulsed operation in some condition, and resulting effect can be that the pulsed power can be higher than expected (depends on frequency and current as well as optics used)
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laser safety in commercial products.
