Olympus E top illumination problem

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Robo
Posts: 3
Joined: Tue Jul 27, 2021 6:31 pm

Olympus E top illumination problem

#1 Post by Robo » Tue Jul 27, 2021 7:09 pm

Hello everyone,

I've had this microscope for more than a decade. It's an Olympus model E, with an epi-illumination option:
Image

I can find very little information on it online; apparently this illumination type was not very common. I use it to make pictures of integrated circuits.
Image

This microscope has been working perfectly for a long time. Recently however, I've been seeing smudges on the image. As it turns out, these are present on the mirror inside the illumination unit. The smudges move when I turn the black knob in the picture above. Below is what the mirror attached to it looks like:
Image

I removed as much dust from the mirror as I could, using a very soft brush, but the smudges remain. It looks like the mirror surface is degrading, as if bubbles are forming inside the coating. It's hard to capture this in an image, but below is what I managed using a stereo microscope:
Image

Now of course my question is, is there any way to fix this? I guess cleaning won't help if the coating is disintegrating, and would in fact make it worse. Is there any way to replace this part? Or would I be better off replacing the whole microscope with something more modern?

PeteM
Posts: 2983
Joined: Tue Dec 06, 2016 6:22 am
Location: N. California

Re: Olympus E top illumination problem

#2 Post by PeteM » Tue Jul 27, 2021 10:56 pm

If it were mine, I'd try things in this order:

1) Gentle solvent cleaning to see if the white spots can be teased off.

2) Replacement of the half mirror. My recollection is that these are simply cemented in place and Edmund or others might have one that fits

3) A cheap replacement from Ebay etc.; either of just the epi head or an entire scope with a good epi head.

4) Just picking up another used epi scope. Around here $200-300+ should be enough to get something with a brighter lamp and DIN plan epi objectives.

Where are you located - that can affect availability of parts.

Robo
Posts: 3
Joined: Tue Jul 27, 2021 6:31 pm

Re: Olympus E top illumination problem

#3 Post by Robo » Wed Jul 28, 2021 8:33 pm

Thanks PeteM! As for your suggestions:

1) The little white spots are dust, but the smudges are real damage to the mirror, so cleaning probably won't fix it.
2) You mean I could just replace this piece of coated glass, and glue a replacement into that brass (?) frame? Where could I find such a mirror?
3) I've tried this; it appears to be a very rare part, and so far no luck.
4) This is the other obvious option. Would $300 really get me a quality microscope with epi illumination and high-magnification plan objectives? I've found epi illumination to be quite unusual and therefore hard to find at a reasonable price. Any suggestions for specific models to look for?

I'm located in Europe, specifically the Netherlands.

PeteM
Posts: 2983
Joined: Tue Dec 06, 2016 6:22 am
Location: N. California

Re: Olympus E top illumination problem

#4 Post by PeteM » Thu Jul 29, 2021 1:28 am

Robo wrote:
Wed Jul 28, 2021 8:33 pm
Thanks PeteM! As for your suggestions:

. . .
2) You mean I could just replace this piece of coated glass, and glue a replacement into that brass (?) frame? Where could I find such a mirror?

Edmund Scientific in the US would be a source. There are likely European equivalents. This isn't the right size and perhaps not the right quality, but a Chinese version: https://www.aliexpress.com/item/1005001 ... 66391f1-11

3) I've tried this; it appears to be a very rare part, and so far no luck.

I've seen both complete scopes and piles of epi parts on US Ebay - might expand your search?

4) This is the other obvious option. Would $300 really get me a quality microscope with epi illumination and high-magnification plan objectives? I've found epi illumination to be quite unusual and therefore hard to find at a reasonable price. Any suggestions for specific models to look for?

These scopes are more likely to appear used at low prices in places with semiconductor manufacturing facilities. Here in "Silicon Valley" California you might find a wide variety of Olympus BHM, Nikon Optiphot, and Leica and Reichert epi microscopes. I've found all four makes at prices from $200 to $500; often requiring a bit of work (e.g. broken illuminators or in need of a mechanical tuneup) or missing a lens or two. European locatons with some long-established semiconductor facilities might be good places to check for used microscopes.

I'm located in Europe, specifically the Netherlands.

Good luck - epi scopes are cool.

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Rossf
Posts: 363
Joined: Mon Jan 20, 2020 12:39 am
Location: Victoria Australia

Re: Olympus E top illumination problem

#5 Post by Rossf » Mon Aug 02, 2021 7:55 am

Hello Robo-I’ve got the same model-the marks look like smudges-my only suggestion is to try zeiss cleaning wipes-I’ve had a few objectives that I couldn’t get smudge marks of front element until I tried these wipes-picture below-in Australia you can get them in supermarkets.Worth a try as they are pretty cheap-
Good luck
Ross
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Robo
Posts: 3
Joined: Tue Jul 27, 2021 6:31 pm

Re: Olympus E top illumination problem

#6 Post by Robo » Tue Aug 10, 2021 7:37 am

Thanks Rossf and PeteM! I think I've seen these lens wipes, I'll give them a try. But I'm pretty sure the big smudges are actual damage to the mirror, so this will probably not fix that.

Replacing the mirror with a new piece of glass seems risky to me; if it doesn't work then I can no longer use the microscope at all... So I think my best bet is to look for a newer microscope. They're less expensive than I would have thought, so it's actually quite an attractive option.

I am familiar with the local semiconductor industry; In fact I work in this sector myself, and it's also where my current microscope came from. I've seen several threads on this forum with useful information about the different models and features, so I'll go and see what fits my budget.

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