wjm@mruxc.UUCP (B. Mitchell) (08/21/86)
A quick technical question for those of you out in net.land:-- What is the frequency or wavelength of the light produced by the lasers in CD players?? I suspect it is either IR around 850 nm or in the red region around 650 nm, but was curious to know for sure. Also does anyone have the reference to the original Phillips Tech Review articles describing the CD system. I seem to have misplaced mine when I moved. Thanx, Bill Mitchell (mruxc!wjm) 186,000 miles/sec - its not just a good idea, its the LAW!
dh@vax135.UUCP (David N. Horn) (08/29/86)
Sharp sells a laser diode for compact disc players. It puts out 5mw of optical power at 780 nm - just visible red. The part number is LT022 and it can be obtained from Diplomat Electronics (201)785-1830 for about $26 one off. They also have some laser diodes up to 40mw at 830nm. I have a few. Dave Horn, AT&T Bell Labs, Holmdel, NJ. vax135!dh
dave@onfcanim.UUCP (Dave Martindale) (09/02/86)
In article <1570@vax135.UUCP> dh@vax135.UUCP (David N. Horn) writes: >Sharp sells a laser diode for compact disc players. It puts out 5mw of optical >power at 780 nm - just visible red. 700 nm is the generally-recognized end of the visible spectrum - 780 nm is near-infrared. For comparison, a He-Ne laser's light is 633 nm, red LED's are about 655, and a ruby laser produces light of 694 nm. So, if you're playing with laser diodes, be careful - you won't be able to see the beam, but it can cause eye damage. 1mw is considered a "safe" level for visible lasers, since even if you accidentally get the full beam in the eye you will blink fast enough to prevent damage. Eye damage will occur only if you avoid blinking. With an infrared laser, you won't blink, and even a laser with much less than 1mw output could burn your retina if you look at it long enough.
drg@briar.UUCP (09/03/86)
In article <115@mruxc.UUCP>, wjm@mruxc.UUCP (B. Mitchell) writes: > Also does anyone have the reference to the original Phillips Tech Review > articles describing the CD system. There are four articles in Philips technical Review, vol 40, No. 6, 1982, pp 151-179. Don Gentner Philips Labs
rab@well.UUCP (09/09/86)
<WHAT line ea
In the reference article excellent points are made about safety with
Lasers in general. Without minimizing that, I'd like to mention that
I was under the distinct impression that Infrared light does not penetrate
the cornea (very well) and thus an Infrared Laser is much less likely
than a visible one to damage the retina. (Maybe it will still damage the
cornea, however....) Or is it because we are here discussing Near Infrared
light, that this point becomes moot?
--
Robert Bickford {lll-crg,hplabs}!well!rabdon@nscpdc.UUCP (Don McGlauflin) (09/16/86)
In article <1747@well.UUCP> rab@well.UUCP (Bob Bickford) writes: ><WHAT line ea > > In the reference article excellent points are made about safety with >Lasers in general. Without minimizing that, I'd like to mention that >I was under the distinct impression that Infrared light does not penetrate ^^^^^^^^^^ >the cornea (very well) and thus an Infrared Laser is much less likely >than a visible one to damage the retina. (Maybe it will still damage the >cornea, however....) Or is it because we are here discussing Near Infrared >light, that this point becomes moot? > >-- >Robert Bickford {lll-crg,hplabs}!well!rab *********** WARNING! INFRARED LASERS ARE VERY DANGEROUS TO THE EYES! ********** Please! Please! Please! Don't post this kind of stuff unless you KNOW. I have a friend who was permanently blinded by a 20 mw infrared laser. It took only a fraction of a second. He says: "I couldn't tell when it was on, or where it was pointed, because I couldn't see it." Moral: be careful!