0.72 NA Condenser for darkfield at 40x and below

[ffesti]

I need to meditate a bit over this. 5 degrees of freedom is quite a lot for this small of a space. Especially if you want at leasr some of them to be independently adjustable.

[j.stirling]

@Chacob

Something to note: I measured the focal lengths for the lenses that I used but when I applied the lens equations to them to find the conjugate image planes (required for the kohler condenser aperture positions) I found that the real position of the aperture was off by quite a large margin. The lenses I used were less than perfect and were the culprit. I’m bringing this up because unless you build out an optical train test bench, like the one pictured in my original post, you won’t be able to determine the position of the elements in a given condenser programatically by the stats of the lenses. The parameters of the new CAD will need to set the relative positions of each object in the train using the real world measurement of the test-benched objects.

That is a fair point. yeah, we would need pretty reliably spec’ed lenses to actually programmatically set things

@Chacob

@j.stirling I can put these into drawings no problem. I did create both condensers within OnShape so I could also link that instead if you would like to have access to all dimensions/objects. Would you like the source CAD, drawings, or both?

Drawings are great for reimplementation, so is source CAD. It seems I can access OnShape on Linux? I have never tried, but yes source would be useful too, my understanding is that source CAD can’t be downlowded in OnShape but in theory it should be perpetual?

[Chacob]

@j.stirling OnShape is browser based so it should port well to linux. The only issues you may have is with the hardware acceleration that may or may not be needed to render in browser.

Here are links to the public document. I created both condensers within the same document but saved them as different versions. There is virtually no parameterization of the objects in this document; save for the light stop used in the darkfield condenser. It’s a prototype doc so it’s a mess.
Darkfield condenser

Kohler condenser

Note that the kohler condenser does not include the apertures - I used the ones from this thingiverse link. The gaps are included - the apertures are about 8mm thick.

[j.stirling]

No worries about hardware acceleration every computer I own is getting on for 10 years old and doesn’t have much hardware to accelerate anything anyway! I’ll have a play later in the week

[WilliamW]

2+1 degrees of freedom is all we need surely? At >0.5NA small angular misalignment is not really relevant.

However the xy position adjustment could be done by angle adjustment instead if that were easier.

My take would be to use the existing separate z-axis from the Upright (would need to move back to give space for the larger condenser, but that could be done in the spacer). Then xy adjustment on an aperture in Kohler, or on the LED itself in non-Kohler. I think the xy position of the lenses will be OK within print accuracy.

I need to do a bit of testing to see how well aligned things are.