dave wrote:
I just bought one of those laser levels and am very pleased with it. However I
think it makes sense to get some laser safety goggles. The laser is "only" 1mW
class II but still I think it makes sense. Anyone know somewhere (in uk) I can
get such goggles? Thanks.

It really, really isn't important to get goggles, honest.

I used to work with lasers (in a lab), and I can tell you
categorically that 1mW red won't do your eyes any harm at all
unless you stare into it for several seconds. In the same way a
pencil won't do your eyes any harm unless you poke yourself in
the eye with the sharp end.

A quick look into the beam won't do you any harm.

More to the point, at 1mW, any decent laser goggles will result
in you not seeing the dot/line except for in very dark situations.

--
Grunff

dave wrote:

On Fri, 29 Aug 2003 13:26:39 +0100, Andy Dingley wrote:


On Fri, 29 Aug 2003 12:31:58 +0100, dave wrote:


I just bought one of those laser levels and am very pleased with it. However I
think it makes sense to get some laser safety goggles.

No, they'll make it useless as you won't see it. If you're worried
about safety, just keep the background lights on (small pupils). Just
don't stare into the thing, and you'll be fine.

The red-lensed goggles that come with some of them are for contrast
enhancement, not for safety.

BTW - there are two sorts of safety goggles; dye and interference
filters. The first sort are useless and expensive - you might as well
wear cheap welding goggles. The second sort are insanely expensive
(hundreds and hundreds), but wonderful as they only stop one very
narrow wavelength band and you can still see while you're wearing
them.

I used to work in Class 4 laser labs. Injuries were fairly common,
almost all of them being from people walking into the corners of
equipment racks in the near-dark. It was a good justification for
getting the good goggles.


Thanks. Good to have some real-world advice. My main concern was that when laser
is in rotating mode, it might bounce off eg a mirror and someone gets an
eyefull. Ok so as long as used "sensibly" goggles not needed.



Ive looked down one of those lasers. Its nothing. FAR worse to look at
the Sun, or a welding torch. Looking at page 3 of the Sun has made some
people go blind.

"Peter Crosland" wrote in message
...
On the same subject are the ones on offer next week at Lidl for £17.99 any
good?




I want a refund! The one I bought from Lidl some months ago was a couple of
quid dearer than that.

It does what I want of it, laying verticals for paper hanging for example,
although I could probably get much better than the claimed +/- 0.5mm/m
accuracy by paying £400 for one from my local builder's merchant.

Colin Bignell

I want a refund! The one I bought from Lidl some months ago was a couple
of
quid dearer than that.

Thanks Colin. I KNEW I would not please everyone!

Malcolm Stewart wrote:

NOT true.
Back in 1963, I suffered temporary blindness from one of the early HeNe lasers
shining mode patterns onto the slightly reflective skin on the back of my hand -
and this was before manufacturers had managed to get the power of these lasers
up to the 1mW level. ( We were lucky to get 1/10 mW in those days.)

Are you saying you got "temporary blindness" just looking at the
reflection of a sub-mW hene off your skin? I think not.

--
Grunff

"Grunff" wrote in message
...

Are you saying you got "temporary blindness" just looking at the
reflection of a sub-mW hene off your skin? I think not.

--
Grunff

Absolutely certain about it.
I spent some time looking at the 3 x 2 mode pattern and for two weeks afterwards
I could see this same pattern whenever I relaxed my eyes and looked at a plain
surface. The demo was in a slightly darkened room (always a bad thing) and if
you examine the back of your hand there's a little specular reflectivity there.
Fortunately, it didn't last longer than 2 weeks - and it was in 1963, when I was
supposed to be working on cutting edge stuff! I do remember that it was some
time before we were able to measure laser power levels with any real precision,
and the academic journals were full of articles on how best to do it.

--
M Stewart
Milton Keynes, UK
www.megalith.freeserve.co.uk/oddimage.htm

Malcolm Stewart wrote:

Absolutely certain about it.
I spent some time looking at the 3 x 2 mode pattern and for two weeks afterwards
I could see this same pattern whenever I relaxed my eyes and looked at a plain
surface. The demo was in a slightly darkened room (always a bad thing) and if
you examine the back of your hand there's a little specular reflectivity there.
Fortunately, it didn't last longer than 2 weeks - and it was in 1963, when I was
supposed to be working on cutting edge stuff! I do remember that it was some
time before we were able to measure laser power levels with any real precision,
and the academic journals were full of articles on how best to do it.

Hmmm...

I suspect if you arranged a few medium brightness LEDs (not
hyperbright, maybe 50mCd or so) in a pattern, and spent some
time staring at them in a darkened room, you'd be seeing that
pattern for a while afterwards.

Doesn't mean there was any retinal damage, just that you've
saturated a bunch of cells which are taking a while to recover.
Very surprised by the two weeks though.

--
Grunff