Jewel Beetle

Images taken in a controlled environment or with a posed subject. All subject types.

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mjkzz
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Post by mjkzz »

thanks, I think I will get those coaxial stuff when I come back from vacation. I saw one in a machine vision/robotic show last year and it was cheap, maybe I will give them a call.

Lou Jost
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Post by Lou Jost »

Rik, as you said, if you do that with a mirror, you cause aberrations. To avoid that, it should be better to use the method I linked to, a half-silvered front-surface mirror reflecting the subject into the lens. A light behind the mirror fills in the black shadows. The light from the object doesn't pass through the mirror, so there are no aberrations.

Lou Jost
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Post by Lou Jost »

My guess is that those instruments linked by Lou do not have pellicle beamsplitters, but instead just thin glass or maybe even prisms. Placed behind the objective, there is no need for the thinness of a pellicle, and glass would be a lot more robust.

Rik, I can't vouch for all optical comparators, but at least some of them do use pellicle mirrors, according to their specs. See for example:
https://www.mqs.co.uk/nikon-pcb31000-pr ... 31001.html

Note that these seem to be finite lenses, so there is a good optical reason for the use of pellicle mirrors instead of thicker glass mirrors.

Edit: I bought several of these comparator lenses to experiment with, and their mirrors are completely invisible.

rjlittlefield
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Post by rjlittlefield »

Lou, thanks for the reference. It seems very clear that the PCB31000 does use a pellicle.

So then, from the standpoint of re-purposing used equipment, the issue would become: what do you do with a microns-thick pellicle that has been integrated by the manufacturer into the innards of a device like those comparators?

I've never had one of these in hand, so I don't know for sure, but I certainly expect that harvesting and reusing the pellicle will not be at all like harvesting the lens from a scanner.

--Rik

Lou Jost
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Post by Lou Jost »

The idea would be to harvest the whole tube segment containing the pellicle. This just involves removing the lens. Whether that is easy or not depends on whether the lens unscrews. If so, you're done! Easier than disassembling a big scanner.

mjkzz
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Post by mjkzz »

found this little guy (trying to escape hurricane?) in kitchen, never stacked a spider . . . yeah, there is that black hole!

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