More and more people are interested in building and experimenting with IR laser setups.
Looking through the treads on NUI Group, I’ve seen a lot of warnings (from various people) about potential damage that the IR laser can cause to your eyes.

I believe that we are all here on this group because we not only have sufficient technological insight and knowledge, but also a good common sense. So please use it when working with IR lasers.

The light from the IR laser modules is invisible and because it does not cause any blink response, it will damage your eyes if looked directly into it.
Always use laser IR blocking protection glasses when working with lasers!!!

Neither I nor anybody else on the NUI Group will be responsible for any injury or damage to anybody caused by a missuse of these IR laser modules.
Please use these IR laser modules in a safe and responsible manner!

UPDATE: Please read the laser class information below.

~Alex

Thanks for the warning, i’ll be sure to be carefull..

Some extra cautious with lasers from a CD/DVD players, even though they are labelled as Class 1 ("eye-safe under all operating conditions") this is only because they are housed and are not directly exposed, officially these laser are often Class 3R/3B and therefor dangerous.

Any laser product of a given Class may contain ‘embedded’ lasers which are greater than the Class assigned to the product, but in these cases engineering controls (protective housings and interlocks) ensure that human access to radiation in excess of product Class is not possible. Notable examples of this are CD and DVD players which are Class 1 laser products while containing Class 3R or Class 3B lasers and laser printers which are Class 1 laser products but contain Class 4 embedded lasers.

Laser Class information

Out of interest Alex, what class would you say your lasers are?  And if we are spreading the beam using a lens surely the danger is reduced (once installed etc)?  Basically, lasers for a final product for the public to use will still be ok, as long as they can’t get their eyes into a position whereby they fry them.

Larky - 01 July 2008 02:04 AM

Out of interest Alex, what class would you say your lasers are?  And if we are spreading the beam using a lens surely the danger is reduced (once installed etc)?  Basically, lasers for a final product for the public to use will still be ok, as long as they can’t get their eyes into a position whereby they fry them.

You are correct. The laser’s total output power is spread evenly accross the light plane and the farther you go the lower the light intensity is.
Looking at the various specs and laser class definition, I would say that the 850nm 10mW IR laser modules fall into Class IIIb devices.
As a reference to this take a look at this document and this web page.

Here is the description of Class IIIb device taken from laser safety wiki page:

Old System

Class IIIb

Lasers in this class may cause damage if the beam enters the eye directly. This generally applies to lasers powered from 5–500 mW. Lasers in this category can cause permanent eye damage with exposures of 1/100th of a second or less depending on the strength of the laser. A diffuse reflection is generally not hazardous but specular reflections can be just as dangerous as direct exposures. Protective eyewear is recommended when direct beam viewing of Class IIIb lasers may occur. Lasers at the high power end of this class may also present a fire hazard and can lightly burn skin.

Revised System

Class 3B

A Class 3B laser is hazardous if the eye is exposed directly, but diffuse reflections such as from paper or other matte surfaces are not harmful. Continuous lasers in the wavelength range from 315 nm to far infrared are limited to 0.5 W. For pulsed lasers between 400 and 700 nm, the limit is 30 mJ. Other limits apply to other wavelengths and to ultrashort pulsed lasers. Protective eyewear is typically required where direct viewing of a class 3B laser beam may occur. Class-3B lasers must be equipped with a key switch and a safety interlock.

~Alex

Glad this is a sticky post/topic,
Prominent and Bolded so it’s easily seen by people,
unless it’s too late and they are already blinded.

Alex , have you experimented with 5mW lasers? With the line lense they should be the safest , falling between class 2b and 3a.

AlexP, thank you for warning the people on NUI Group for testing this specific solution. I appreciate it as well as all the others.

We’re looking into ordering safety goggles for the office. Since I would never want to be telling my grandkids “… and back in 2008, I was trying to build some LLP multi-touch surface and we saved $30 on safety glasses, and that’s why I wear this eye patch.” —I’d love some second opinions
Does anyone know if these would suffice:  http://store.oemlasersystems.com/index.php?main_page=product_info&cPath=8_10_16&products_id=46

Would it be possible to use a lower intensity laser?  I’d love to make a multi touch for my little girl and me to play with, but I can’t really reconcile the danger of damaging her eyes.

hello,
i want to buy a IR laser module, can you tell me the concrete model of it that you uesd in your experiment. thank you !

Do you know if lasers with line lens mounted on are dangerouns to look at from the point of view of a person using an LLP screen/table?

Not looking straight into the laser module, but at a certain angle

my main concern would be light “escaping” the intended line/beam due to line lens manufacturing imperfections

Thanks for letting me know.

I would be safe but what kind of lasers do you have?

Aixiz (sp?)

at the moment, testing things with 780nm 10mw, but planning to get a few 850/880 ones with higher power/mw
aixiz 120 degrees line lens

im using cd burner laser diode. . i read it’s class I.i try it using 5 volt adaptor 1 Ampere. the ir light so weak. any clue please?

This topic is very interesting but there are few things I don’t understand.

Each time I read a topic about LLP setup, I see lots of warnings about the use of lasers. OK, I understand that a laser directed right into my eyes will damage it. But none of us use a laser with a straight beam. We all use them with line generator lenses. So how dangerous are they with line generator lenses ? For example, I bought two 780nm 25 mw IR lasers from Axiz with 120 line generator lenses. What are the risks ?

If there are risks, how to reduce them in the final product ? For example, in Dubaï TouchWall, they used 30 10mw IR lasers. I didn’t see any special protections in their final installation to protect end-users. Were they right making a LLP TouchWall if lasers were dangerous ?

I think this topic would be a very good place to explain at the end how to use lasers in LLP setups with no risks. I mean what are things to add to the structure of a TouchWall or TouchTable to protect end-users.

The appealing thing with an llp setup is that it relatively easy and not that complex to do. Just mount a couple of lasers with a line lens on the plate, adjust them and the line lens and put a diffuser on the rear side of the plate.

The real danger of the use of infra red lasers is that you can’t see it when the laser light shines into your eyes. That is the reason I ordered 780 nm lasers after reading an article that they work well (http://arbi.trario.us/2008/11/02/diy-laser-multi-touch-table/ ). To be on the save side I choose for 5mw and 10 mw with 90 degrees line lenses. If the laser light reach your eyes you will see a red light so you know you have to look another way.

I have tried to find info on the internet but it is not all as clear as I hoped it would be. I think the challenge is to limit the risk of thinks going wrong with the construction of the llp setup. Lasers have to mounted/glued/integrated in a way that they can’t turn or drop down or whatever thing might happen that make the laser light shine another direction as intended. The line lens have to be attached pretty well to the lens because without the line lens the laser is magnitudes more dangerous then with line lens.  (I assume)

With normal use and lasers and line lenses that stay in place and the laser light just mm above the surface you really have to give it an effort to get the laser light into your eyes. Playing around with little round dentist mirrors might do the trick. But there is always and everywhere the risk of people behaving stupid, unresponsible, dangerous, selfdestructive etc.  So lets all be very carefull and use our brains and common sense. 

Does anyone has a pointer to European regulation from a consumer perspective about using laser light in devices . I found info about safety precautions for people working with lasers but that is not what we are looking for I guess.

Erik