Bausch & Lomb DIC Adapted to Olympus with 3D Printed Dovetailing

[microb]

I attached a Bausch & Lomb DIC adapter to an Olympus metallurgical microscope with 3D printed dovetail adapters.

Side note, because the Olympus is infinity focus and the B&L was designed with a fixed tube length, the adapter has paired lenses top and bottom, sandwiching the Nomarski prism so as to fake out not adding an inch and half to the tube length.

So here is a silicon wafer with and without the lenses. But the first is with no DIC. The second with. Notice in the DIC that there are pond shaped defects above the two boxes. B&L Balpman might be 210 tube length.

The microscope is an Olympus BHMJL. Seems to work. To be honest, I don't know anyone with B&L microscope.

[apochronaut]

The Balplan might be what is called a modified infinity corrected microscope. The optical system includes a group of low power, high N.A. semi-objectives which issue a convergent beam to a common correcting negative doublet above the nosepiece, that also collimates the beam as far as the telan lens in the head, which then converges the beam to the eyepiece. The Balplan does have a tube length, even infinity corrected microscopes do but the section in which optical accessories such as a polarizing analyser or the DIC prism are located, is in fact in the collimated or infinity corrected section of the optical path.

Due to the this rather unique optical design, it is difficult to determine just what it's tube length is . It would have to be measured from the top of the negative doublet because that lens is in fact the rear lens of all of the objectives, so it has a rather short tube length as an infinity corrected system, something on the order of 150 mm might be the case. I could measure it reasonably accurately.

[apochronaut]

So, I did a quick measurement and your total tube length is about right. The infinity section of the optical path, measured from the top of the collimating/telescope lens is about 60mm to the telan lens. The telescope lens is the back lens of each objective, so measuring from there is the equivalent of measuring from the objective shoulder in other microscopes. Balplans have an unusually long head. Then from the telan lens through each set of prisms it is about 150mm to the top of the eyepiece tubes, so +- 210mm of which about 60 mm is infinity and 150mm is convergent.
Contrast this to the AO infinity system, which does not use a telescope lens; the objectives are pretty much finished in the barrel, except for a small amount of moderation in the telan lens. The series 400 are about 80mm to the telan lens.

[microb]

Got the CNC aluminum proto-type to test to day. Ultra-cool.

Need to add dovetails to the rings. But it fits.

[75RR]

Notice in the DIC that there are pond shaped defects above the two boxes.

Just to mention that the pond shapes you mention (and ascribe to incorrect tube length?) are visible in both images. The DIC just seems to have emphasized them, which is in fact its job.

[billbillt]

Hi Microb,

I think you have done a great job here and view the "ponds" as trivial in the overall performance..

BillT

[microb]

When I wrote about the pond shape defects, I didn't mean defects in the DIC. I meant that the DIC was emphasizing the defects on the surface.

For tube length, I was talking about the B&L is not infinity focus. So I took out the two lenses that fake-out the B&L tube length. The Olympus is infinity focus, so the DIC adapter in the optical path does not need the lenses.