Green Laser Pens - Are they legal?
Farouq
Can anyone say whether the high powered green lasers are legal to sell
and purchase in the UK.
I'm getting conflicting answers on this one.
I know that standard presentation laser pens are just 1mw and generate
a red light.
I have noticed an increasing number of very high powered lasers (35mw
and more) for sale which produce a green light.
Ian Stirling
> Hi all,
>
> Can anyone say whether the high powered green lasers are legal to sell
> and purchase in the UK.
No.
>5mW is not legal to sell as a 'laser pointer'.
Bastards at customs confiscated some red laser pointers of mine, and
wouldn't give them back, as they had measured 2% over the threshold.
Marcus Fox
"Ian Stirling" <ro...@mauve.demon.co.uk> wrote in message
news:44074268$0$70292$ed26...@ptn-nntp-reader03.plus.net...
Well, I know several astronomical societies that use them for star pointing.
Marcus
Cynic
<ro...@mauve.demon.co.uk> wrote:
>> Can anyone say whether the high powered green lasers are legal to sell
>> and purchase in the UK.
>
>No.
I have legally purchased a laser from a reputable UK supplier that I
am sure was more than 5mW. Not sure what colour it is because I have
only viewed it in operation through a protective tinted glass safety
shield (it looks green through that), but the way it cuts through
steel and the very large power supply makes me pretty certain that it
has more than 5mW power output.
Though I suppose it is possible that Paliament decided to repeal the
laws of thermodynamics.
--
Cynic
Steve Walker
>Not sure what colour it is....
>....but the way it cuts through steel...
Do you also have the appropriate table to strap spies to.......?
:o)
M. J. Powell
<please-reply-via-newsgroup-th@-i-posted-to.com> writes
They don't reach that far, do they?
Mike
--
M.J.Powell
sidthedid
I'm not sure about handheld ones but at least one university I know of
uses a high power laser for ablation of old shell samples (it's a
complicated dating technique, a bit like counting tree rings) and i'd
assume that laser is well over anything you could use handhheld (the
unit it's in is about the size of a pool table).
Aside from using it as a weapon, what is their objection?
sid
Steve Robinson
"sidthedid" <sp...@yahoo.co.uk> wrote in message
news:44077dd3$0$23293$db0f...@news.zen.co.uk...
i think green lasers require more power than the red
Marcus Fox
"M. J. Powell" <mi...@pickmere.demon.co.uk> wrote in message
news:tGZwtjUG...@pickmere.demon.co.uk...
They don't have to. The perception is a green beam pointing out to infinity,
and people can look along the beam and see the star (or planet) of interest.
Works very well.
Marcus
Marcus Fox
"Steve Robinson" <st...@colevalleyinteriors.co.uk> wrote in message
news:CtLNf.29130$wl.1...@text.news.blueyonder.co.uk...
Not necessarily. The eye is more sensitive to light in the middle of the
visible spectrum between 200 and 800 nm. Guess which colour this is? See
http://members.misty.com/don/photopic.html. But it is possible to have very
highly powered red lasers.
Marcus
Scott
Lasers used in inertial confinement fusion are about the size of a football
field and deliver about 10^24 W/cm^2.
Alasdair
<ro...@mauve.demon.co.uk> wrote:
>Bastards at customs confiscated some red laser pointers of mine, and
>wouldn't give them back, as they had measured 2% over the threshold.
Did they quote the relevant regulations to you either at the port of
entry or in subsequent correspondence?
There was a bit of a hoo-ha about five years ago when some kids
pointed laser pointers at passing drivers causing temporary blindness.
This may have resulted in a tightening up of the regs.
--
Alasdair.
P Darby
>>pointing.
>
> They don't reach that far, do they?
They do reach that far, but it takes quite a while...
Daytona
>Can anyone say whether the high powered green lasers are legal to sell
>and purchase in the UK.
Bloody auditors getting tooled up, are they ?!
Daytona
Cynic
Yes - but it would have to be a small spy. The table is only 1 metre
per side. The apparatus is used to cut precision metal stencils under
computer control - the stencils are used to put solder paste onto
electronic printed circuit boards)
--
Cynic
Dave (from the UK)
> I'm not sure about handheld ones but at least one university I know of
> uses a high power laser for ablation of old shell samples (it's a
> complicated dating technique, a bit like counting tree rings) and i'd
> assume that laser is well over anything you could use handhheld (the
> unit it's in is about the size of a pool table).
>
> Aside from using it as a weapon, what is their objection?
>
> sid
>
I'm not a lawyer, but have used lasers a lot of my working life.
Neither am I an expert on laser safety, but from what I do know.
An item having a laser must have a sticker which states the class of the
laser. A class 1 laser is eye safe - in principle so safe you could
stare at it all day and it not hurt you. A class 4 laser is unsafe - so
much so that a beam that is reflected from pain, carpet, whatever could
burn your skin (not just your eyes).
Between class 1 and 4, there are various classes (not the 2 and 3 you
might think). The problem is that many lasers are marked as class 1,
indicating they are eye-safe, but are in fact far more powerful than
permitted by a class 1 laser. A colleague of mine measured a laser with
a class 1 sticker at 5x the permitted power for that.
Under classifying lasers, to make them look safe, but work well is common.
So that is why customs probably confiscated the lasers that someone said
were 2% over the limit. If that same laser has a sticker on it saying
class 3B, it is very likely it would have been permitted here.
Note, things like CD-ROM drives will have lasers inside which are
dangerous, but are considered safe and so have a class 1 sticker, since
you are not expected to open it up.
One other thing, the safety of lasers depends not only on the power, but
the wavelength (colour) too. If you can see the laser and it is bright
then you tend to blink. That protects your eyes. If the wavelength is
well away from the visible, your eyes can't focus the light properly, so
that tends to protect your eyes.
Other issues occur with short sighted people - they are more at risk.
It really is a complex problem.
You might well be in legal issues if you sell a laser that is marked as
class 1 and someone subsequently gets their eyes damaged. Especially now
someone has enlightened you of the issues that do affect lasers.
I don't know if this is still accurate, but it used to be said that the
only person to be killed by a laser was when it fell on him. Some lasers
have dangerous voltages too. Neither will effect laser pointers of course.
--
Dave K
Minefield Consultant and Solitaire Expert (MCSE).
Please note my email address changes periodically to avoid spam.
It is always of the form: month-year@domain. Hitting reply will work
for a couple of months only. Later set it manually.
Odie Ferrous
>
<snip>
> One other thing, the safety of lasers depends not only on the power, but
> the wavelength (colour) too. If you can see the laser and it is bright
> then you tend to blink. That protects your eyes. If the wavelength is
> well away from the visible, your eyes can't focus the light properly, so
> that tends to protect your eyes.
But surely the eye's ability to "focus" doesn't necessarily coincide
with the potential damage caused by a laser?
Are you implying that a laser will only damage an eye if that eye can
focus on it?
(Sorry - not legalese and certainly off-topic - but fascinating stuff,
all the same.)
Odie
Dave (from the UK)
> "Dave (from the UK)" wrote:
>
> <snip>
>
>>One other thing, the safety of lasers depends not only on the power, but
>>the wavelength (colour) too. If you can see the laser and it is bright
>>then you tend to blink. That protects your eyes. If the wavelength is
>>well away from the visible, your eyes can't focus the light properly, so
>>that tends to protect your eyes.
>
>
>
> But surely the eye's ability to "focus" doesn't necessarily coincide
> with the potential damage caused by a laser?
>
Yes it does.
If the eye focuses the light, it will more likely damage the retina,
since all the power is dissipated in a small spot.
If the light is not focused on the retina, the light will be spread over
a larger area and so the power density (or heat dissipated per square
mm) will be lower.
> Are you implying that a laser will only damage an eye if that eye can
> focus on it?
No. Just that all other things being equal, if the light is focused to a
small spot on the retina, it will more likely do damage than if it is
not focused.
Hence visible lasers can present more of a hazard than invisable ones
due to the focusing.
But the fact that you can see the light from visible lasers, and so will
blink if in your eye, tends to make them less dangerous than invisible
ones. (However, the regulations assume you do blink if you see the
laser. If you are stupid enough to stare at a laser, you can still
damage your eye on a laser such as a class
Also important is whether optics are used to view the laser. For
example, if you were trying to align a fibre against a semiconductor
laser, you would look though a microscope to see what you are doing. In
that case, it adds an additional risk.
Laser pointers are much more dangers than bare semiconductor lasers, as
they have a lens that collimates the light (keep it in a thin line).
Other issues occur with pulsed lasers. The average power can be low, but
the high peak powers can provide for non-thermal damage mechanisms.
On high power lasers, it is immaterial whether you can see them or not -
they will damage your eye, but on lower powered devices, it depends on a
lot of factors.
It is a *very* complex issue. The regulations are extreamly long and
difficult to follow. People who were involved in writing the regulations
enjoy a nice income from explaining how to interpret them.
There is very expensive software sold that is supposed to determine the
risks.
Apart from optical risks, there are also risks associated with high
voltages, poisonous chemicals or simply the weight of other lasers.
Oh, and by the way, laser markings in Europe are not the same as used in
the USA.
Jonathan Bryce
> But surely the eye's ability to "focus" doesn't necessarily coincide
> with the potential damage caused by a laser?
>
> Are you implying that a laser will only damage an eye if that eye can
> focus on it?
Think what happens when you focus the rays from the sun on a sheet of paper.
Dave (from the UK)
Well put - why did I not think to put it that way?
Francis Burton
Cynic <cyni...@yahoo.co.uk> wrote:
>I have legally purchased a laser from a reputable UK supplier that I
>am sure was more than 5mW. Not sure what colour it is because I have
>only viewed it in operation through a protective tinted glass safety
>shield (it looks green through that), but the way it cuts through
>steel and the very large power supply makes me pretty certain that it
>has more than 5mW power output.
I legally purchased a green laser pointer from Roithner LaserTechnik
in Austria. No problem with customs - maybe I was lucky? It claims to
have a power output of 20mW. It doesn't cut through steel(!), but it
could blind someone so is used with some care.
Francis
Ian Stirling
> On Thu, 2 Mar 2006 19:10:04 +0000, Ian Stirling
> <ro...@mauve.demon.co.uk> wrote:
>
>>Bastards at customs confiscated some red laser pointers of mine, and
>>wouldn't give them back, as they had measured 2% over the threshold.
>
> Did they quote the relevant regulations to you either at the port of
> entry or in subsequent correspondence?
Not directly, they referred to a laser standard that was only available
for (IIRC) 150 quid.
A depressing trend - being unable to argue the case without paying for
the standards.
(reposted - as it has not come through, and I don't think it was that
controversial)
gareth erskine-jones
wrote:
>Hi all,
>
>Can anyone say whether the high powered green lasers are legal to sell
>and purchase in the UK.
I don't see why not. Health and safety regulations set limits on the
power of lasers where people might be exposed to the light, but I
don't think that affects your personal ownership of a more powerful
laser.
>I have noticed an increasing number of very high powered lasers (35mw
>and more) for sale which produce a green light.
and you can make a 250mw one with a few components and the laser diode
from a DVD writer.
GSEJ
Dirk Bruere at NeoPax
One technical point.
A green laser is made by frequency doubling IR light from an IR laser
diode. The resulting green beam can have a considerable amount of IR
laser light mixed with it, which can be very damaging.
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.blogtalkradio.com/onetribe - Occult Talk Show
Lordgnome
"Dirk Bruere at NeoPax" <dirk....@gmail.com> wrote in message
news:7rf77a...@mid.individual.net...
> A green laser is made by frequency doubling IR light from an IR laser
> diode. The resulting green beam can have a considerable amount of IR laser
> light mixed with it, which can be very damaging.
An interesting point. The police of course, have no compunction in directing
quite a powerful pulsed IR laser at motorists - i.e. in hand-held speed
scameras.
Les.
Dirk Bruere at NeoPax
If the pulses are short enough so that the average power level is low,
then no problem.
OTOH high power near IR lasers are extremely dangerous because there is
no blink reflex to be triggered and no indication that your eyes have
been illuminated except for blindness. By the time you feel the heat its
too late.
Obviously one concern of govt is terrorist use of such lasers. They can
blind from several km distance and the beams are invisible.
http://www.youtube.com/watch?v=EveB9W55zv0
The red dot you see is probably a red sighting laser superimposed on the
IR beam.
Here's a YAG used for engraving
http://www.youtube.com/watch?v=3w249OaA07g&feature=related
Both of these lasers are legal to own but are extremely dangerous. Even
a stray reflection will cause permanent eye damage if no eye protection
is worn.