I am Using Olympus IX71 microscope. hence I am trying to fix the kohler illumination before going to the phase contrast mode. When I am trying to allign after following every steps carefully again and again I am getting image of the light source i.e. iamge of filament in the image plane..... I succesfully did it previously with the same microscope. But Once I disassembled the condenser lense from the microscope.. after that time this problem has been started..........please give me suggestion
Full disclosure - I have not used this microscope. However, in basic form, Köhler illumination uses two lenses. The first gathers light from the light source (your light bulb). The second lens images the first lens, NOT the light source, onto your illumination plane. Typically, the first lens is its focal length distance away from the light source. This produces a "collimated" output beam from the first lens. The second lens is then twice its focal length from both the first lens and the illumination surface - a simple one-to-one imaging of the first lens to the illumination plane. I do not know what adjustments you have. If you can only move the whole illumination assembly, it is probably too close to the illumination plane. Move it away by about a factor of about two. If you can only move the second lens, it is too close to the illumination plane and needs to be moved back by about a factor of two.
Some Köhler illumination systems have a diaphragm on the output of the first lens. You can reduce the size of this diaphragm and adjust your system until the edge of this diaphragm is in focus on your illumination plane. Then open it up again for normal use.
Please note that manufacturers may use compound lenses for each of the simple lenses I mentioned above, and may use a more complex optical system to save space. The basics should still apply. You probably need to move something in your illumination system quite a bit further away from your illumination plane.
Good luck!
Agreed. It is possible when you replaced the condenser it was not seated properly (possibly tilted just a bit or too distant from lens). You probably retried reseating it; it this did not work and your focal plane is still bringing the filament into view I would contact Olympus for a solution.
Not sure about this particular microscope, but it is often possible to reverse the conDenver lens (upside down). The simple fix may be to flip the lens. Worth a try…
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