MicrobeHunter.com Microscopy Forum

Are there DIC prism shear values stated somewhere for the Leica, Nikon, Zeiss, Olympus?
Considering the frameless stress-gradient DIC prisms could be manufactured quite cheaply, it may be beneficial to try to gather list of different manufacturers DIC prism shear values as a reference.
Frames for the prisms are also quite cheap and easy to 3D print. Example of 3D printed Leica prism frames and frameless stress-gradient prism (largest on image is stressed polycarbonate):
https://drive.google.com/file/d/1WIEHas ... drive_link

I am not familiar with frameless stress gradient prisms. How do they work?

There's this: From:
https://www.researchgate.net/publicatio ... modulation


Also this: From:
https://www.researchgate.net/publicatio ... Microscopy


Michael Shribak may have published more data points elsewhere in his papers, but It was a while since I was digging through this literature.

Good luck finding the shear values. I've only seen a few for the UIS Olympus objectives, and those had been determined by the researchers who wrote the book. Those tend to be rather jealously guarded secrets.

Edit - the post above lists the only ones I've ever seen. And those are not from the manufacturer.

Basically Sanderson prisms without the external stress frame, pretty much any method works as long the correct stress gradient is created in the polymer.

Scarodactyl wrote: ↑

Sat Oct 14, 2023 6:06 am

I am not familiar with frameless stress gradient prisms. How do they work?

Those are pretty nice finds, thank you!

viktor j nilsson wrote: ↑

Sat Oct 14, 2023 6:29 am

From:
https://www.researchgate.net/publicatio ... modulation

From:
https://www.researchgate.net/publicatio ... Microscopy

Michael Shribak may have published more data points elsewhere in his papers, but It was a while since I was digging through this literature.

tpruuden wrote: ↑

Sat Oct 14, 2023 5:24 pm

Basically Sanderson prisms without the external stress frame, pretty much any method works as long the correct stress gradient is created in the polymer.

Scarodactyl wrote: ↑

Sat Oct 14, 2023 6:06 am

I am not familiar with frameless stress gradient prisms. How do they work?

Having built my own Sanderson plate, I can't see how the system could be modified to properly deform thin materials:
A Sanderson plate is a PITA to get to focus on the condenser back focal plane. A "frameless stress gradient prism" would be ideal...assuming they're easier to make than grinding your own quartz prisms, which, I've looked into doing. Not that big of a deal to do, but without knowing manufacturer spec might be a waste of time.

I suspect that these prisms, assuming that they're 3D printed, have incorporated some of the natural warping that occurs when printing this kind of thing? But on what axis?

I would also be very interested to learn more about the frameless stressed materials as well as the used shear angles - And especially the typical differences in shear angles for the condensor-side prism. The article above stating the Olympus-angles is about the objective-side and you can see the relationship between focal length of objective and the resulting displacement on the sample. It has the form: tan(shear)*focal-length = displacement

However, for Sanderson-type prisms one has a much better chance to replace the condensor-prism, as usually there is better access to the vicinity of the back focal plane at the condensor side. The objective-prisms most are Nomarski-type ones (interference-plane is NOT inside the prism by changing the optical orientation of one of the wedges). How can you mimic this with a Sanderson? Or is that wrong?

This is UV filter casing from HOYA. One can see the residual stresses resulting from the injection molding. There are multiple methods for creating the stress gradients for organic materials, some seem to be giving reasonable results.
What considers the Nomarski vs Wollaston prisms and back focal distance, the focal distance can be modified by stacking the prisms to some extent, as shown in the patent microb found:
https://patentimages.storage.googleapis ... 0723A1.pdf

To drive further the discussion - edge view:

You know that's one of those 3-D visual puzzles don't you? Is that the upper right corner looking down from the outside upper right or the upper right corner looing up from the inside lower left?

Puzzle is all quite simple - laminate frame stressed Sanderson prism between glass plates. Remove frame. Trim excess.
Or use suitable laser to ablate internal matrix on the edge areas to create expansion stress - have not yet tested this.
I was trying to see, if anyone has more interesting approaches...

Upper right corner, looking down from the outside upper right (illustrative image).

apochronaut wrote: ↑

Mon Nov 20, 2023 11:33 am

You know that's one of those 3-D visual puzzles don't you? Is that the upper right corner looking down from the outside upper right or the upper right corner looing up from the inside lower left?