Alt-BEAM Archive
Message #05803
To: beam@sgiblab.sgi.com
From: SG Sparkyg@seark.net
Date: Fri, 20 Aug 1999 00:57:44 -0400
Subject: [alt-beam] Re: anuther obsticle avoider thingy
sorry to keep on this, but i need to mention one more thing:
>>>(ya know those little keychain laser pointers
>>>come to mind! ...but thats not IR now, is it?) i dunno.
>>>thats for the techno gurus to figure out.
Well actually, some Lasers ARE IR. and they are very well defined.
These are found mostly in CD players.
i even found the following info and MORE information including
a tutorial on how to remove such items at:
http://plop.phys.cwru.edu/repairfaq/sam/laserdio.htm#diotoc
---------------------------------
CD player and Other Low Power IR Laser Diodes:
The major difference between these and the visible laser diodes discussed
in the section: Low Power Visible Laser Diodes is that the output is
near-IR - usually at 780 nm (wavelengths from 400 to 700 nm are generally
considered the visible portion of the electromagnetic spectrum). Therefore,
the emission is not readily visible and you must use an IR detector device
to even confirm that the laser is operating properly. This also means that
safety is even more of a consideration with these devices since what you
cannot see CAN hurt you (or at least your vision).
Thus, these devices make truly lousy laser pointers or laser light shows as
the emission is just barely visible in subdued light. If you hoped for a
Star Wars type laser beam, better go hunting for a 25W argon laser. :-)
However, for data or voice communications, various kinds of scanning or
sensing, and electro-optic applications where visibility is not needed or
not desirable, such low cost sources of coherent light are ideal.
Similar types are found in CDROM drives and newer LD (LaserDisc) players.
CD-R recorders, Minidisc equipment, magneto-optical, and other writable
optical drives including WORM drives, use devices that are similar in
appearance and drive requirements but may be capable of somewhat higher
maximum power output - as much as 30 mW or more.
Modern laser printers use laser diodes producing anywhere from 5 mW to 50
mW and beyond depending on their resolution and speed (pages per minute).
High resolution laser imagers, typesetters, and plotters, may use laser
diodes producing 150 mW or more. (However, equipment built before 1985 or
so may use helium-neon or even argon lasers rather than diode lasers.)
------------------------------
this is interesting...
but i'll shut up for now!
-Sparky
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