Laser Pointers on the Skin

[NSM]

One thing I've discovered about laser pointers is that the chip area
is purposely constructed so that it is impossible to collimate the
beam to make it into a dangerous device. What I think happens is that
there are multiple lasing areas which are slightly out of phase with
each other. When one tries to concentrate the beams onto a very tiny
spot they tend to subtract from each other and cancel out.

I suspect that if the 'point' was finer it would make a worse pointer.

N

 

[webpa]

Jerry G.

This thread is about LASERS, not LIGHT EMITTING DIODES (LEDs); the
sites you reference are NOT about LASERS. You'd best learn the
difference before you injure yourself or someone else.

 

[NSM]

And how many of us didn't take a magnifying glass when we were kids and aim
the sun at hour hands. Done right, that can actually burn, but of course
we'd move the glass the second it hurt. No damage done.

Except to the ants!

N

 

[Sam Goldwasser]

One thing I've discovered about laser pointers is that the chip area
is purposely constructed so that it is impossible to collimate the
beam to make it into a dangerous device. What I think happens is that
there are multiple lasing areas which are slightly out of phase with
each other. When one tries to concentrate the beams onto a very tiny
spot they tend to subtract from each other and cancel out.

Not really true, see my other posting on this topic.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

 

[NSM]

Not really true, see my other posting on this topic.

I've been told that these are the lasers used in grocery scanners, or
rejects from them. In that case I suspect they want to minimise eye damage
AND get reliable scans. The geometry may be designed for that.

N

 

[Michael Black]

Except to the ants!

But that's different, since the feedback was missing.

Michael

 

[Sam Goldwasser]

I've been told that these are the lasers used in grocery scanners, or
rejects from them. In that case I suspect they want to minimise eye damage
AND get reliable scans. The geometry may be designed for that.

To the best of my knowledge, that's not true. They are the same type of
laser diodes as used in barcode scanners and those are single transverse
mode diode.

Laser diodes are difficult to collimate and focus, but that's the nature of
the beast. It is possible though.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

 

[Ugly_Georges]

As a final conclusion : don't point this on your balls !

)

 

[Asimov]

"Ugly_Georges" bravely wrote to "All" (17 Feb 05 23:35:47)
--- on the heady topic of "Re: Laser Pointers on the Skin"

Ug> Subject: Re: Laser Pointers on the Skin
Ug> Xref: aeinews sci.electronics.repair:10823


Ug> As a final conclusion : don't point this on your balls !

Ug> )


.... Don't put your remaining good eye in the path of the laser!

 

[James Sweet]

And how many of us didn't take a magnifying glass when we were kids and aim
the sun at hour hands. Done right, that can actually burn, but of course
we'd move the glass the second it hurt. No damage done.

Michael

Hehe many ants met their end that way when I was little.