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If the optics themselves are not damaged, I'm surprised Zeiss can't simply
take the lens apart, clean out the oil, then reseal it.  I have had some
luck getting liquids out of lenses by putting the lens in a vacuum bell for
a while.  If you are seeing oil inside the lens, either the front seal is
going/gone, or the oil is dripping down the lens to the spring-loaded part
(if your lens is spring loaded) and getting in there.

Craig


On Mon, May 27, 2013 at 5:37 PM, Claire Brown, Dr.
<[log in to unmask]>wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> We are relatively routinely seeing oil inside of our Zeiss 63x oil
> immersion lenses. You end up with a bead of oil inside that acts as a lens
> itself and the lens is unusable.
>
> As far as we can tell, it usually happens after prolonged use over many
> years. We are at a point now where our lenses are "old" and Zeiss cannot
> repair them because the parts are no longer available. It costs us $6-8,000
> to replace them. With 13 microscopes we have one lens failing every 6-12
> months or so. I can't afford to keep replacing these lenses and with this
> becoming a "routine" occurrence I want to seek out advice about why this
> might be happening. Our users are well trained and I don't think it is
> neglect by them. I think this is due to routine use.
>
> I have two questions:
>
>
> 1)      "Is there a defect in how these lenses are made?"
>
> For example, perhaps the seals on the front lenses degrade over time - we
> inspect our lenses regularly and many that have had oil inside have no
> obvious damage by visual inspection. Maybe they need to be resealed every
> year or two, maybe an internal seal degrades over time? Preventative
> maintenance of these lenses or a change in how they are manufactured would
> certainly cost less than $8,000 I would think.
>
>
>
> 2)      "Do people have a similar problem with oil immersion lenses from
> the other major manufacturers?"
>
> I look forward to some input here.
>
> Sincerely,
>
> Claire
>
>
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> Claire M. Brown, PhD - McGill University - Assistant Professor, Physiology
> - Life Sciences Complex Imaging Facility Director
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