DIY epi-illumination through eyepiece port

Here you can discuss DIY adaptations to the microscope.
Post Reply
Message
Author
jjtr1
Posts: 33
Joined: Sat May 07, 2022 8:51 am

DIY epi-illumination through eyepiece port

#1 Post by jjtr1 » Thu Jul 07, 2022 1:58 pm

Since used Nikon epi-illuminators are unfortunately too expensive for my budget, I was thinking of using one of the eyepiece ports of my Nikon YS2-H's bino head as an illumination port (with LED). But the reflection of the illuminating beam on the beam-splitter face drowns out the image coming up from the objective.

Perhaps a pair of polarizers could diminish the reflection enough to make it usable. Do you think it is worth trying? I'm asking before I spend money on polarizers.

(External illumination doesn't work with my 40x, that's why I want internal.)

Adam Long
Posts: 110
Joined: Tue Jul 14, 2020 11:37 am

Re: DIY epi-illumination through eyepiece port

#2 Post by Adam Long » Thu Jul 07, 2022 2:09 pm

To be honest this can be a problem even with dedicated epi heads (I have a Zeiss Universal).

Crossed polarisers are the solution, albeit with the loss of much light, but closing down the field diaphragm to exactly match or slightly vignette also helps a lot.

So I'd suggest looking at ways to collimate your light source and control off-axis light to a minimum, if possible.

Edit: Alternatively, you may well find it is possible to pick up a whole scope configured for epi much cheaper than converting your existing one. That's what I did.

Scarodactyl
Posts: 2775
Joined: Sat Mar 03, 2018 9:09 pm

Re: DIY epi-illumination through eyepiece port

#3 Post by Scarodactyl » Thu Jul 07, 2022 3:53 pm

Perhaps consider one of the infinity optiphot illuminators. The bottom dovetail is the smaller labophot one and needa annoying shimming to fit just right in an eclipae, but the top dovetail accepts eclipse sized heads.
They look like this
https://www.ebay.com/itm/323674829900
Usually with some digging one can be found on eBay with a lamphouse, kr you can adapt on a fiber optic light guide.

PeteM
Posts: 2986
Joined: Tue Dec 06, 2016 6:22 am
Location: N. California

Re: DIY epi-illumination through eyepiece port

#4 Post by PeteM » Thu Jul 07, 2022 4:26 pm

Another option is a finite illuminator for scopes of the Alphaphot-Labophot-Optiphot era.

One can often find Nikon finite epi illuminators cheap, especially if the back bits of plastic to hold the halogen lamp are broken. It's much easier to patch these up and use something like LED or fiber optic illumination than to try to re-engineer a regular binocular or trinocular head so that stray light is trapped. You'll have a mirror designed for reflected light with minimal scattering, housings properly blackened to handle light going the "wrong" way, field and iris diaphragms to control the epi light, and slots for polarizers.

Here's one example: https://www.ebay.com/itm/224361749738?h ... Swt9JgM~rb

In the Bay Area and other areas with surplus from old semiconductor wafer inspection kits, they're sometimes both in better shape and sold cheaper.

As Adam suggests, you might even find a fairly complete scope at an attractive price.

grassthe
Posts: 3
Joined: Mon Jul 25, 2022 8:14 am

Re: DIY epi-illumination through eyepiece port

#5 Post by grassthe » Mon Jul 25, 2022 8:18 am

Nikon finite epi illuminators can frequently be found for a reasonable price, particularly if the back pieces of plastic that are meant to hold the halogen lamp are broken. Instead of attempting to re-engineer a regular binocular or trinocular head so that stray light is trapped, it is much simpler to just patch these up and use something to illuminate the scene, such as LEDs or fiber optics. You will have a field and iris diaphragm to control the epi light, a mirror that is designed for reflected light with minimal scattering, housings that are properly blackened to handle light that is traveling in the "wrong" direction, and slots for polarizers.

Post Reply