2 of 2
2
IR Laser Safety!!! [ READ THIS ]
Posted: 08 January 2009 08:13 PM   [ Ignore ]   [ # 16 ]
Rank
Joined  2009-01-08
Total Posts:  16
New Member

I’d like to try to clear up some of your worries and possible mis-understandings with lasers (particularly in the IR spectrum) for use as an illumination device on a table.

First - I am new to this forum - it’s up to you to listen or not, you don’t know who I am etc.. But -

I’ve been working with lasers since ‘92 - everything ranging from 5mW to 40W pulsed YAG lasers.

Low Power IR laser diodes: So the laser is classed as class 3something. It’s not worth going into class 4 which is what all entertainment lasers are, as most people won’t get a chance to lay their hands on one. With IR lasers, you cannot see the beam (or spread beam after going through a lens or grating) with your naked eye but it is still there. And if it has enough power, it can damage peoples eyes, but a 25mW diode with a line lens on pretty much most definately cannot. The fact that it is IR makes no difference to what happens when shon into the eye. A laser beam is a laser beam no matter what its wavelength is.

I’ll try to explain why a laser beam is especially bad for your eyes thus all the hoo ha: When you look at something, it’s light travels into your eye, through the lens and ends up upside down on your retina. The size of the thing you look at relates to the size it ends up on your retina. You might have tried this with a magnifying glass projecting the image from a window onto something behind. A laser beam is different: Because the light is coherent (all the light waves travelling the same direction from the same source), your eye see’s it as an object of infinate focus and the lens focusses the beam down into the tinyest sized point of light on your retina.

To safety and handling these beasts:

Rule 1: Provide a steady mounting platform. You don’t want it to move while your using it cos it’ll screw up your sensing.

Rule 2: use your camera to help you level the lasers output over the surface - you can’t see IR, but the camera can

Rule 3: Don’t worry about the power and ‘safety’ - It’s too low power and too confined to worry about.

Profile
 
 
Posted: 13 January 2009 04:28 PM   [ Ignore ]   [ # 17 ]
Avatar
Rank
Joined  2008-08-24
Total Posts:  49
New Member

I’ve sent an email to AixiZ to find out what class their cheap IR laser are, as well as how the line generators effect class. They replied with the following email:

780 5mw would be class IIIR (used to be known as IIIA)
780 10mw is class IIIB

The rating would change with a line generator since it would spread out the beam power. In this case, both lasers would be most likely Classs II or IIIR

Please see attached.

Chuck

> Subject: Enquiry from AixiZ
>
>
> Hello,
>
> I was wondering what class would the 780nm 5mW Laser Module and the 780nm
> 10mW. Also how does the rating change with a 120 and 89 degree line
> generator. Any other safety tips would also be appreciated.
>
> Thank you

The attachment they sent is an pdf file for standard laser safety, titled “American National Standard for Safe Use of Lasers” (ANSI Z136.1). This file contains loads of information about laser safety, we could perhaps interpret it and add the information to the wiki. I’ve attach the file to this reply for anyone who would like to read it. (http://www.google.com/search?hl=en&q=American+National+Standard+for+Safe+Use+of+Lasers.+&aq=f&oq=&aqi=)

File removed because of copyright violation.

Profile
 
 
Posted: 17 January 2009 09:06 AM   [ Ignore ]   [ # 18 ]
RankRankRankRank
Joined  2007-01-08
Total Posts:  1008
Member

Sounds like a good initiative Sniperchang, thanks for the pdf

Profile
 
 
Posted: 17 January 2009 09:48 AM   [ Ignore ]   [ # 19 ]
Avatar
Rank
Joined  2008-08-24
Total Posts:  49
New Member

No problem, glad I can be of some help.

Profile
 
 
Posted: 18 January 2009 06:23 PM   [ Ignore ]   [ # 20 ]
Rank
Joined  2009-01-08
Total Posts:  94
New Member

ok, just had a look at that pdf and im still a little unsure. so to put it in English are the 780nm 10mW 3.2VDC 12 x 30mm Laser Module not safe as i have a litte boy that will be around the table with the lasers and dont what to damage my sons eyes. if they are bad what other options do i have as i would like to use a glass top on an LCD screen.
thanks.

 Signature 

My MT Blog
http://mymultitouchproject.blogspot.com/

Profile
 
 
Posted: 18 January 2009 09:25 PM   [ Ignore ]   [ # 21 ]
Avatar
RankRankRankRank
Joined  2008-06-09
Total Posts:  905
Moderator

gfunk2k:
Safety precautions should definitely be taken. If all goes well during operation of your setup and no laser light escapes, you’ll be fine, but if you do get the beam in your eyes, you’re risking eye damage. LLP setups are very popular, even in public displays, but enclosures to make sure the laser light doesn’t escape is necessary.

If you’re worried about it, just for peace of mind, I would avoid lasers, particularly with small children...but just to clarify: for general use, they’re safe (given safety is taken into account), but I wouldn’t take the chance with small kids.

There are several other options you have for LCD setups - FTIR and LED-LP are two that have been done successfully. FTIR LCD setups: http://multitouch.fieryferret.com , http://multitouch.geomentary.com/ . LED-LP LCD setup: http://peauproductions.blogspot.com . FTIR can be difficult (even impossible) for some with LCD setups, because of the necessity of a compliant surface , which is not perfectly transparent, and would obscure the picture of the LCD. The two projects that I linked to above, however, had success without a compliant surface. LED-LP is essentially LLP, except with LEDs - much safer than lasers. A FTIR-like array of LEDs is created, but without the acrylic centerpiece. This results in a IR plane of light, much like that created by IR lasers.

hope this helps,
rbedi100

 Signature 

My Multi Touch Blog
Join us on NUI Chat !
Read Multi-Touch Technologies Book!

Profile
 
 
Posted: 18 January 2009 10:08 PM   [ Ignore ]   [ # 22 ]
Avatar
Rank
Joined  2008-08-24
Total Posts:  49
New Member
gfunk2k - 18 January 2009 06:23 PM

ok, just had a look at that pdf and im still a little unsure. so to put it in English are the 780nm 10mW 3.2VDC 12 x 30mm Laser Module not safe as i have a litte boy that will be around the table with the lasers and dont what to damage my sons eyes. if they are bad what other options do i have as i would like to use a glass top on an LCD screen.
thanks.

I read it some more, and as far as I can tell, as long as the display is emitting light under the MPE (Maximum Permissible Exposure) it’s safe. So this means that you need to arrange your table so the laser light doesn’t escape, or is diffused, so that it doesn’t emit anything were it shouldn’t. So make sure that the light plane is properly aligned so as to not escape the table, or reflect off the surface of your acrylic/glass, and the light is diffused (Matte finish on the sides). Also, make sure your boy is aware of it. Make sure no shinny objects are placed on the surface, and adequate supervision depend on age/maturity.

Also if your doing this on a LCD like you said, then the 5mw laser will probably be more than enough anyway.

A nice alternative is to use “Side DI”, IR LEDs are pretty bright and can do pretty close to what a LLP does. If you put the LED on the side (Like blocking half the LED) of the LCD so that it doesn’t light up the diffusing LCD layers, but light up just above the LCD, then your blobs can be pretty good. If you really feel uncomfortable with the Lasers (wich seems the case), you could try this approach first.

Profile
 
 
Posted: 19 January 2009 07:00 AM   [ Ignore ]   [ # 23 ]
Rank
Joined  2009-01-08
Total Posts:  94
New Member

thanks for all the info. might be moving away from lasers now, not worth the risk.
as for the LED options. you say that they are allot safer but is there still a risk. say i put a wine or beer glass on the table and that bounced the light could this also cause damage to my eyes?
not trying to go off the subject of this post but im using a 19” screen but the table will be 60cm / 60cms so if i put the LEDs on the edge of the glass would that be to far away for it to work?
thanks again

 Signature 

My MT Blog
http://mymultitouchproject.blogspot.com/

Profile
 
 
Posted: 19 January 2009 11:46 AM   [ Ignore ]   [ # 24 ]
Avatar
RankRankRankRank
Joined  2008-06-09
Total Posts:  905
Moderator

Using IR LEDs is safe - look at this reply on this thread explaining why lasers are dangerous - http://nuigroup.com/forums/viewreply/25208/ . Again, using LEDs is fine - no safety concerns.

There are many, many FTIR or LED-LP setups working at distances much greater than 19” diagonal, so that’s fine - the density of LEDs and how many sides you put them on is what matters. While, in theory, you’ll have TIR with LEDs on just one side, the more LEDs the better. You also want to get good, bright LEDs - look at this post on the ‘ideal’ LED specs: http://nuigroup.com/forums/viewreply/15983/ .

rbedi100

 Signature 

My Multi Touch Blog
Join us on NUI Chat !
Read Multi-Touch Technologies Book!

Profile
 
 
Posted: 08 April 2009 09:14 AM   [ Ignore ]   [ # 25 ]
Avatar
RankRank
Joined  2008-05-31
Total Posts:  122
Member

Basic Laser Safety - Eye

The part of the human body that is most sensitive to light and can most easily be damaged by lasers is the human eye.  Common sense precautions such as not shining a laser into your own, or anyone else’s eyes, will help prevent vision loss from laser exposure.
safetyS.gif

Eye Hazards

The major danger of laser light shows is hazards from beams entering the eye since this is the organ most sensitive to light. The simplest way to explain this is to say, “just as a magnifying glass can be used to focus the sun and burn wood, the lens in the human eye focuses the laser beam into a tiny spot than can burn the retina”.
Lasers in the visible and near infrared range of the spectrum have the greatest potential for retinal injury, as the cornea and lens are transparent to these wavelengths and the lens can thus focus the laser energy onto the retina. The maximum transmission by the cornea and lens, and the maximum absorption of laser energy in the retina occurs in the range from 550 nM to 400 nM. Argon and YAG lasers operate in this range clearly making them the most hazardous lasers. Wavelengths of less than 550 nM can cause a photochemical injury similar to sunburn. Photochemical effects are cumulative and result from long exposures (over 10 seconds) to diffuse or scattered light.
Laser damage and retinal burns can occur when a laser beam enters the human eye. Lasers are a ‘point source’ of light much like the sun thus the eye focuses on infinity when viewing lasers especially in a darkened space where no other light sources are present. Laser beams are almost parallel thus the lens of the human eye will focus them down to a small spot. A laser beam with low divergence entering the eye can be focused down to a spot 10 to 20 microns in diameter.
The laws of thermodynamics do not limit the power of lasers. The second law states that the temperature of a surface heated by a beam from a thermal source of radiation cannot exceed the temperature of the source beam. The laser is a non-thermal source and is able to generate temperatures far greater than it’s own. A 30 mW laser operating at room temperature is thus capable of producing enough energy (when focused) to instantly burn through paper!
Due to the law of the conservation of energy, the energy density (measure of energy per unit of area) of the laser beam increases as the spot size decreases. This means that the energy of a laser beam can be intensified up to 100,000 times by the focusing action of the eye. A one watt laser beam when focused down to a small spot can produce temperatures higher than the surface temperature of the sun! Thus even a low power laser in the milliwatt range can cause a burn if focused directly onto the retina.

NEVER point a laser, even a laser pointer, at someone’s eyes no matter how low the power of the laser.

Structure of the eye

The part of the eye that provides the most acute vision is the Fovea Centralis (also called the Macula Lutea). This is a relatively small area of the retina (3 to 4%) that provides the most detailed and acute vision as well as your colour perception. This is why you move your eyes when you read or when you look as something; the image has to be focused on the fovea for detailed perception. The balance of the retina can perceive light, and movement but not detailed images (peripheral vision).
If a laser burn occurs on the Fovea, you can loose most of you fine (reading and working) vision in an instant. If a laser burn occurs in the peripheral vision it may produce little or no effect on fine vision. Repeated retinal burns can lead to blindness.
Fortunately the eye has a self defense mechanism, the blink or aversion response. When a bright light hits the eye it tends to blink or turn away from the light source (aversion). This MAY defend the eye from damage where very lower power lasers are involved but cannot help where higher power lasers are concerned. By the time the eye reacts, the damage is already done. Due to the focusing effect discussed above, a one watt laser beam entering the eye can be focused to 100,000 watts per square centimeter of power at the retina.
eyelaser.gif

Lens of the eye focuses a laser beam buring the retina

Eye damage can also occur when laser beams are scanned across the eye even for very brief periods. The amount of exposure is difficult to estimate as ‘dwell’ or ‘transit’ time must be taken into account in your calculations. For example a 1 mW laser illuminating a 7 mm aperture (the average size of the dark adapted iris) for one second is the equivalent of a 10 mW laser illuminating the same 7 mm aperture for 1/10 of a second.
The international laser safety standard, IEC-825, defines a short exposure as 2.5 mW per square centimeter. Each jurisdiction has it’s own maximum exposure levels for laser radiation. You should consult with your local regulatory authorities and get their official methodology and formula(s) for calculating the MPE (Maximum Permissible Exposure).
Symptoms of a laser burn in the eye include a headache shortly after exposure, excessive watering of the eyes, and sudden appearance of many ‘floaters’ in your vision. Floaters are those swirling distortions that occur randomly in normal vision most often after a blink or when you have had your eyes closed for a couple of seconds. Floaters are caused by dead cell tissues that detach from the retina and choroid and float in the Vitreous Humour. Ophthalmologists often dismiss minor laser injuries as floaters due to the very difficult task of detecting minor retinal injuries.

i found it on the Internet i thot i might post it here people might need it. rasberry

 Signature 

MT LCD
MT Wall

Profile
 
 
Posted: 04 October 2009 12:21 AM   [ Ignore ]   [ # 26 ]
RankRank
Joined  2009-03-13
Total Posts:  188
Member
a1laserboy - 08 January 2009 08:13 PM

I’ll try to explain why a laser beam is especially bad for your eyes thus all the hoo ha: When you look at something, it’s light travels into your eye, through the lens and ends up upside down on your retina. The size of the thing you look at relates to the size it ends up on your retina. You might have tried this with a magnifying glass projecting the image from a window onto something behind. A laser beam is different: Because the light is coherent (all the light waves travelling the same direction from the same source), your eye see’s it as an object of infinate focus and the lens focusses the beam down into the tinyest sized point of light on your retina.

i’d like to know if using a line generator nullifies that effect. because the light is spread out, then i assume the beams no longer focus to a sigle point, so it acts like regular light. Is this the case or is it still dangerous to look into the flat plane?

and another thing to remember is that IR lasers act like normal lasers and you often see specular/diffuse reflections when using laser aligning tools, laser pointers etc. which are no cause for alarm. I wouldn’t be concerned with lasers once in place on the table unless they aren’t mounted securely or someone will be placing mirrors on the table which is a very unlikely scenario.

Profile
 
 
Posted: 11 April 2010 03:17 PM   [ Ignore ]   [ # 27 ]
Rank
Joined  2008-11-13
Total Posts:  22
New Member

Are there any Class 1 IR lasers that people use?
I have searched online and every place I find has like Class II or Class III IR lasers. The thing is I have a Microsoft Laser Mouse 7000 and it is labelled as a class I laser. I took out my camera and IR filter to test it out and sure enough there’s a nice little 850nm laser in there. The laser isn’t enclosed so if you turn the mouse upside down and look at the bottom the beam is pointing right in your face.

Profile
 
 
Posted: 02 June 2010 02:07 AM   [ Ignore ]   [ # 28 ]
Rank
Joined  2010-05-31
Total Posts:  28
New Member

Dear Sir/Madam,

Have a nice day!

And I am very glad to say that Line-infrared Laser Module is our new product, it is used on IR Touchscreen, the details as follows:

A.Line-infrared Laser module of imaging angle is 92-93 degrees

B.Laser module line output power>30mw

C. Laser module line uniformity >80%( 1m distance ,the projection line of about 2.1m).

D.Laser modules in the range of 0-2m, the projection word width<3mm, the smallest office:1mm.

E.Laser module troble-free service life>8000 hours.

F.Laser module to take anti-static treament.

H.Access to part of the laser module power supply connector using the agreed.

1.  Wavelength: 808nm,850nm

2.  power :5 0mw

3.  Beam path adopt collimation lens+92°powell lenses

4.  operating voltage :DC5V.

5.  operating temperature :-10℃-50℃

6.  storage temperature :-40℃- 85℃
Company full title: Xi’an Lingyue Machinery&Electr.LTD.CN
ADD : No.2 Electronic East Street, Xian ,ShaanXi
ZIP :710065
Website : http://www.lingyuekeji.com
E – mail :xxq2055@hotmail.com
Contact person : Xiangqian Xu
TEL :+86-29 88225187
Mobile Phone :+86-15902998524
Fax : +86-29-88219538

Profile
 
 
Posted: 18 August 2010 07:49 PM   [ Ignore ]   [ # 29 ]
Avatar
Rank
Joined  2010-08-17
Total Posts:  5
New Member

hihi, it is neccessary to wear appropriate laser safety glasses when you are operating lasers. i recommend LSG laser safety glasses for yours.
http://www.qkbuy.com

Image Attachments
AD550x230.jpg
 Signature 

[color=green]enjoy work, enjoy life!

laser safety glasses, laser optics, laser laboratory instruments, DPSS lasers, laser pointers, laser show systems, we supply since 2002.
[/color]

Profile
 
 
   
2 of 2
2