Class II Green Laser for Prototype Design - Angular Spread: 30 Degrees

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Discussion Overview

The discussion centers around the specifications and sourcing of a Class II green laser with an angular spread of approximately 30 degrees for a prototype design. Participants explore various methods for achieving a line-generating feature, including the use of lenses and scanning mirrors, while addressing the technical challenges involved.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Exploratory

Main Points Raised

  • Glenn seeks a Class II green laser with a 30-degree angular spread for a prototype design.
  • Warren suggests that a 30-degree dispersion is more characteristic of a flashlight than a laser.
  • Glenn clarifies that he is looking for a line projection that spreads out only on one plane, not conically.
  • Integral asserts that achieving a line requires scanning the beam, typically done with a galvo mirror.
  • Glenn inquires about laser line-generating lenses and their relation to galvo mirrors.
  • Integral explains that lenses form an image in the shape of a line, while scanning mirrors maintain the integrity of the beam.
  • Glenn states his intention to illuminate a planar section of smoke from a fog machine, necessitating the line-generating feature.
  • Njorl mentions that diode lasers emit elliptical spots and suggests that cylindrical lenses could be used to achieve the desired effect.
  • Njorl provides a link to a commercial green laser diode pointer, indicating availability.
  • Glenn shares his plan to experiment with a clear glass or acrylic rod to generate a line from his laser pointer.
  • Another participant suggests that a half-cylinder lens would be effective for generating a line when the beam shines into its flat surface.
  • A question is raised about how a rod lens can generate a fan pattern or line when a laser beam hits it.
  • A suggestion is made to explore commercial devices for laser light shows, which often use rotating polygon mirrors or galvo mirrors.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of achieving a line projection with a laser, with some suggesting alternative methods and others questioning the practicality of the proposed solutions. No consensus is reached on the best approach or the availability of suitable lasers.

Contextual Notes

Participants discuss various technical aspects, including the nature of laser beams, the role of lenses and mirrors, and the specific requirements for Glenn's application. There are unresolved questions regarding the commercial availability of certain laser types and the effectiveness of proposed solutions.

Glenn
Hi,
I am working on a prototype design. For it I will need a laser with the following specs...

Class II, Green, line-generating laser, with an angular spread of approximately 30 degrees.

Where can I get such a laser?

Thanks,
Glenn
 
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You want a dispersion of 30 degrees? That's not a laser, that's a green flashlight.

- Warren
 
30-45 degrees would be fine for this purpose. NOTE - I am not talking about a conical dispersion. It should only spread out on one plane only which would result in a projected line.

-Glenn
 
You will not find a laser that does that. To get a line you will need to scan the beam. this is generally done with what is called a galvo mirror. (it uses a galvometer mechanism to oscillate the mirror)
 
Integral,
Here is a site I just found that advertises laser line generating lenses. Are these likely to be the same as the galvo mirror you were talking about?

Thanks,
Glenn
 
No, a lens would essentillay be forming an image in the shape of a line, While a scanning mirror maintains the integrity of the laser beam, it just moves it. This what grocery store barcode scanners do.

What are you trying to do?
 
Integral,
I need to illuminate smoke from a fog machine. Except rather than illuminating a large section of it, I need to illuminate a planar section, hence the need for the line generating feature.

-Glenn
 
Diode lasers emit elliptical spots. Some have such a large ellipticity that they appear to be line-emitting. A green, diode laser would be Gan-AlGaN or GaN-InGaN. You could also use cylindrical lenses to form such an ellipse if all you can find are circular-spot lasers.

Problem is I can't recall if those are comercially available yet.

Njorl
 
Well, I just saw ads for a green laser diode pointer, so I guess they are comercially available.

https://secure9.nexternal.com/shared/StoreFront/default.asp?CS=jmm6360&BusType=BtoC&Count1=385509669&Count2=302650094&Target=products%2Easp&CategoryID=14

Njorl
 
Last edited by a moderator:
  • #10
Njorl,

I have a green laser pointer that I use for astronomy purposes. Someone tole me that if I send the laser beam RADIALLY through a clear glass or acrylic rod, I should be able to generate a line on the target. So I am searching going to get some acrylic rod to experiment with.

Thanks,
Glenn
 
  • #11
As Njoral said, a cylindrical lens should work. A glass rod is essentially a cylindrical lens. I think it would work best, though, to have a half-cylinder with the beam shining directly into the flat surface. Also, you want the radius of the cylinder to be close to (but greater than) the beam radius.
 
  • #12
how can a rodlens generate a fan pattern/line when a laser beam hits it?
 
  • #13
Commercial device. Google "laser light show". You can rent or buy.
Usually rotating polygon mirrors or a galvo mirror as Integral says are used.
Example site not a recomendation http://www.taiserver.com/
 
Last edited by a moderator:

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