Can anyone identify this DIC prism?

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PeteM
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Can anyone identify this DIC prism?

#1 Post by PeteM » Wed Apr 03, 2019 12:57 am

I've acquired a DIC prism identical to this one and am hoping to learn what microscope it was intended to fit:

https://www.ebay.ie/itm/MICROSCOPE-PART ... SwpDdVeY8G

My guess is that it went on some sort of reflected light inspection scope -- possibly Reichert or Leica Polyvar -- but the Ebay vendor (Silo Surplus) linked above, Munday Scientific, and a Bay Area microscope place have all come across these. None seem to know what it fits. My intent is to kluge another DIC system together; but it would help to know as much as possible about the origins of this one.

This compensator fits the same system as well:

https://www.ebay.ie/itm/MICROSCOPE-POLY ... SwdsFUOqrk

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wporter
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Re: Can anyone identify this DIC prism?

#2 Post by wporter » Wed Apr 03, 2019 2:08 am

PeteM, it's almost exactly similar to the one I use on my Reichert Univar. I say "almost" because the concave cutout on the thin end has a bit different radius than mine, and some of the screws holding it together are different. I've seen the same slider on a Reichert Polyvar Met, so you're right about that connection.
Actually, I don't know if I have the 'correct' one for my Univar; it came without one, so I had to purchase one from silo. It fits and works fine, though, so no complaints.

One has to be careful in mixing DIC components; this slider does not work well (very narrow DIC band) with some other prisms I have, on a Jena microscope: I will have to find a Jena slider for that system to work.

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Re: Can anyone identify this DIC prism?

#3 Post by PeteM » Wed Apr 03, 2019 2:46 am

Bill -- many thanks for the heads up on the Univar. I've kludged up a rough sketch of the compensator and DIC prism. Both are just under 28mm wide at the top. The compensator has a sort of T shape profile with just under 7mm thick "rails" at the top - and this top profile matches where the DIC prism would insert as well. There's a groove along the left side of both that undoubtably fits some sort of stop screw.

The compensator has a width of just under 22.5mm at the bottom and a thickness of about 16.6mm including the 7mm thick section towards the top.

Think a Univar might accommodate that??

I may end up adapting this to some other scope, but it would be useful to know how far above the objective this is designed to sit.
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wporter
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Re: Can anyone identify this DIC prism?

#4 Post by wporter » Wed Apr 03, 2019 5:29 am

Pete,

Yes, I think that the compensator that you have would fit the Univar slot where I put the DIC slider (upper prism). I think the later Univars and the Polyvars used the same DIC slider I (and you) have. The simpler (earlier?) slider design is illustrated in the manual I translated, on page B10: a combination analyzer and upper prism. I've never seen, or used, one of those. My analyzer is in a separate slot above the other sliders (I'll take some pix to post here tomorrow). There is a separate compensator slot in my nosepiece for a flatter 6 x 20mm style. The Univar I have is not exactly like the one in the manual. I think the early ones had the simple DIC slider entering from the very front, while my more complex version goes in from the right side, about 1/2" above the top of the objectives.

Evolutionarily, I think there was some overlap, or passed-on engineering, from the Univars to the Polyvars, as some other features such as the nosepieces for the Univar seem to have morphed directly into the Polyvar styles. I think the DIC slider was passed on directly. The Univar is "120 pounds of twisted steel and sex appeal". Well, brass, steel, and heavy blocklike components, anyway; whereas the Polyvars were more modern-looking, refined, more integrated into a nifty enclosure, and significantly lighter (60-80 lbs?).

I'll post some images here tomorrow.

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Re: Can anyone identify this DIC prism?

#5 Post by apochronaut » Wed Apr 03, 2019 12:50 pm

There were also the Polycon and Polylite. I don't know how close in their entirety they were to the Polyvar . They show up much less frequently. You have to be careful in searching too because even though they were all presumably made in Austria, some of them show up branded AO. I haven't seen Polyvars like that but I have seen Polylites. It is possible the Polylites were either assembled in Buffalo or had a significant amount of Buffalo manufacturing in them. They would be from pre-1985 due to the name change, prior to the introduction of the series 400.

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Re: Can anyone identify this DIC prism?

#6 Post by wporter » Wed Apr 03, 2019 5:25 pm

Pete,
Here are some images of the DIC slider I use, and the front end of the Univar. Pretty self-explanatory. As you can see, the slider is only very slightly different from the one you linked to above. Don't know what difference it would make. The inside is filled with two dovetails, working the prism up-and-down (supposedly the effect width, though I don't notice much change) and in-and-out (drastic effects on the DIC appearance) in response to turning the knobs.
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PeteM
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Re: Can anyone identify this DIC prism?

#7 Post by PeteM » Wed Apr 03, 2019 9:05 pm

Thanks very much, Bill. Yours looks pretty much the same as the one I have. The slider that is, not that gorgeous microscope you have.

My guess is that I'll try to adapt this to fit inside an Olympus or Nikon intermediate piece -- do a bit of machining to create a slot for it and try various infinity objectives and prisms below. It looks like your DIC slider is positioned pretty close to the nosepiece. There's maybe only 16mm or so from the face of the nosepiece (where an objective snugs up on its threads) up to the top position of the DIC prism??

Any idea of the dimension from nosepiece face to top of the DIC slider? I'll hope to replicate that for starters.

Thanks also, Phil, for the mention of Polycon. If I can find a scrapped Polyvar-Polycon-Polylite stand that could host a new DIC system as well.

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Re: Can anyone identify this DIC prism?

#8 Post by wporter » Wed Apr 03, 2019 10:57 pm

I don't know if the objective-to-prism distance is pertinent on the Univar/Polyvar family, since the prism is in infinity space. Plus the prism can move up and down about 0.8 cm by turning the small inner knob.

But, as near as I can measure it, it is about 1.5 cm from the top of the objective to the top of the slide.

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Re: Can anyone identify this DIC prism?

#9 Post by apochronaut » Wed Apr 03, 2019 11:52 pm

One day, if you have the time, Bill. It would be nice to see a bit of a photo spread on your Univar. They may be getting a bit like a Unicorn and the end is nigh, for chances of seeing a live specimen.

I had forgotten that you have one of those 40X .85 planapos. How much difference is there between it and the 40x .70 planfluor?

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Re: Can anyone identify this DIC prism?

#10 Post by PeteM » Thu Apr 04, 2019 12:20 am

Thanks, Bill.

So far my experience is that infinity objectives are less sensitive to prism placement, but not immune. The 1.5mm is good news - it gives a bit of room.

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Re: Can anyone identify this DIC prism?

#11 Post by wporter » Thu Apr 04, 2019 1:07 am

Glad I could help, Pete. Keep us posted with your DIC experiments. Neat stuff!

Phil: A photo spread of the Univar, eh? I haven't done that because it might be misinterpreted as materialism, or bragging, or some other pathology. I try to keep it low-key, because my feeling is that equipment is (above a certain minimum quality) irrelevant; technique and skill matter more, in most cases.

Plus, it might give newbies the wrong impression, that you need some fancy equipment to have fun, take good images,and explore nature. Far from the truth; there are probably less aberrations in a decent monocular setup with just an objective and an eyepiece (and maybe camera), than in the Univar with its multitude of glass and mirrors. One recalls the amazing resolution turn-of-the-century photomicrographers achieved with diatoms. Mind-blowing!

The Univar was designed to be a convenience, a one-stop shop for researchers, where a number of techniques are built-in and don't need a lot of changing parts and fussing with add-ons to the scope every time one wishes to change technique; the direct predecessor of many of today's better scopes.

All that said, if there is interest, I'll post a few pix. The word on the street is that there were only 300 of the Univars made. Seems a little low.

I'll run a couple of test images off comparing the two objectives, Phil. Gimme a few days. I seem to remember significant differences.

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Re: Can anyone identify this DIC prism?

#12 Post by apochronaut » Thu Apr 04, 2019 2:37 pm

I'm pretty sure there would be a lot of interest in the design and execution of the Univar. It seems that having a look at equipment of all sorts is one of the more popular pastimes on this forum.
Equipment of all sorts is the basis of microscopy and the only thing that separates a standard performing piece from a superior performing piece is the amount of cash both the designers and users are willing to put into it. Sometimes there are "secrets" that someone has discovered and if these can be transferred to the market and fit the economy, all that much better. I read a patent once by Eastman Kodak from 1941 or thereabouts where Max Herzberger designed an objective series based on a super low dispersion glass front element, with a refractive index of over 1.7. The glass, had recently become available, as of 1939. The patented objective but of a design applicable to objectives of other magnifications too, had an N.A. of 1.51. There is doubt in my mind , whether that objective series ever came to fruition as a marketable design, likely due to many practical concerns. When a technical wonder does come to the market and overcomes the hurdles of practical concerns, it is always nice to have a look at it.

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Re: Can anyone identify this DIC prism?

#13 Post by wporter » Thu Apr 04, 2019 5:57 pm

Pete, to continue the thread a bit, here are two DIC sliders, the first on a Polyvar 2 (trans, and epi I think), the second on a Polyvar Met (no transmitted light capability):
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Re: Can anyone identify this DIC prism?

#14 Post by PeteM » Fri Apr 05, 2019 11:39 pm

Thanks for the additional photos, Bill.

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