LASER Trouble

[Paswa]

I am a newcomer diyer in the world of LASER.

Now I've two laser diodes. One was extracted from a CD-RW drive and another from DVD-ROM drive. The first one creates invisible IR beam. So its somewhat useless
But the second one creates a red LASER beam. I made a pointer with it.

The diode just looks like this,, quite different from others. It has 4 pins..


I discovered that the first two pins are + and - pins but I cant figure out the functions of the other two pins.

Have you ever saw or used such Laser Diode ?
There is no any part number printed on the Laser diode that I can search for datasheet. Can you guess the power of the diode keeping it in mind that it was taken from a samsung DVD-ROM? Can you tell me what should be the maximum range of the laser pointer with good lenses if I constust the pointer with this laser diode?


Now talk about focusing lenses. what type of convex any other type of lense (or lenses) should be used in a good laser pointer? And what should be the ideal focal length?

Now talk about health specially eye hazards.

1 :- if I see the laser beam (and NOT the source) with open eyes, is there any risk of damage to retina?
2:- If I see the point of a laser pointer which is focused by a convex lens on a wall or any other place with open eyes, is there any chance of damage to the retina?

3:- Where I live, there is no any LASER safety goggles are available. Though I'll buy a such soon from other place. Can a sunglass(with UVA and UVB protection) will protect my eyes from laser radiation?

[Lsharptec1]

Paswa,

Laser diodes often contain a photo diode in the same package that can be used to indicate that the laser is operating (hence the four wires).

Do an online search for "laser diode", and you will find a treasure trove of data.

The answer to all 3 of your questions is "NO". It is okay to see the beam from the side, or the point on the wall.

Do not look directly into the laser beams path. It would be like staring at the sun.

Good luck and best regards,

Larry

[Paswa]

Laser diodes often contain a photo diode in the same package that can be used to indicate that the laser is operating (hence the four wires).

ohoo, thanks dear... you wanna say that the other two pins work like a photo diode or a phototransistor..to indicate that its working....thanks....I'm checking ya.

And can anybody tell me what should be a good alternative to laser protective glasses or spectacles or eyewears etc?

And what about a DVD-ROM laser diode power? should it be 5-10 mW?