idea for very wide angle scanning

[Nii]

Thoughts?

There will obviously be a blind spot where the cone mirror is attached to + a blind spot from somethng on which the mirror is attached, and also can't shoot to the opposite side since it will hit the projector.

[mixedgas]

That was on the market for a while with a specially shaped spherical reflective optic that reasonably corrected for the distortion induced by the mirror shape. A lens fed the laser light on axis to the shape. It perhaps did not sell very well and was withdrawn after many years on the market. It was expensive to make with precision, hence the cost. There are a few of them in use. Pangolin came up with the Discoscan II and managed to drop the cost from 1000-2000$ for wide angle down to around 300$.
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If you use a conical section like your cone, It will distort the beam shape severely in both axis without the lens and shape correction, think wide oval shaped beam. The shape will change with scan angle. If it were that easy, everyone and their brother would be marketing it as a scan expander.
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Why this obsession with extreme angle? What you want has been done:
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http://pangolin.com/shop/discoscan-lens/
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http://pangolin.com/shop/discoscan-lens/#tab-videos
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The lens in the video already has the distortion correction built into it, correction for color aberration, and has minimal increase in beam diameter. It is not just a wide angle camera lens in reverse.
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A stock 10 mm diameter conical mirror with a 80% reflective coating and decent surface figure is 200$. The DS II is 295$ and the power loss will be far less.
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Steve

[Nii]

I'm aware of Discoscan. This was just an idea I had. Was thinking point beams only.

[buffo]

Hey, look! An axicon in reverse!

Sorry to bring up such a painful subject, Steve, but the analogy seemed apt! Pity it wouldn't work very well (for either application). Would have been nice to see a bunch of reds combined with one. Oh well.

As for the idea of using a fish-eye lens (Disco-scan or equivalent), I can say that I've seen the results with my own eyes, and they're really good even at distances up to 45 feet or so. Much beyond that and you start to notice how fat the beam is becoming though, at least for graphics...

Nii, if you are interested in pursuing this, I suggest you contact Lumia (Aron Bacs) here on the forum. He can probably make you a deal on a lens that will do what you and Steve are talking about - at a price that is far cheaper than a Disco-scan. Not that the Disco-scan is overpriced, mind you. Steve is right in that it does much more than a standard fish-eye would, and that justifies the cost. It's just that Aron has a few surplus lenses that are equally capable that might end up being cheaper.

Adam

[mixedgas]

It's not a bad idea. Just I never had the money to run with it, and the imposter got in the way.

Actually some Polish lab guys ran with the Axicon idea with a slight twist. They had the diamond tipped glass cnc to pull it off. It works gangbusters with xx single mode beams and some additional optics. . I have a four beam. In fact I have a few prototypes some place. Nice piece of precision glass. Works great. Maybe some day I'll have it coated.

PS, There is a way to make a synthetic "Axicon" with reflective and refractive optics, and couple it into a very tiny fiber. But how to do that is pay to play.




Steve