Episcopic Illuminators for Nikon Labophot, Optiphot, Diaphot and Model S Microscopes

Nikon episcopic illuminators Nikon episcopic illuminators

In its most basic form, an episcopic illuminator, also known as a vertical illuminator, is a light source and beamsplitter. They often have provision for aperture and field diaphragms as well as filters. Some are designed for epi-fluorescence, so those have a place for one or more fluorescence cubes.

A well appointed vertical illuminator has two iris diaphrams to control NA (aperture stop) and to limit the field (field stop), as well as a place to insert various filters, such as polarizers, a diffuser, color filters and ND filters. Here we see one with a 50 W halogen lamphouse attached, as well as a rotatable polarizer and fixed analyzer.

Labophot/Optiphot episcopic illuminator with lamp Labophot/Optiphot episcopic illuminator with lamp Labophot/Optiphot episcopic illuminator with lamp

Many Nikon epi illuminators have provision to use the brightfield/darkfield (BD or ED) objectives, with the high NA darkfield annulus as a separate light path. Normal brightfield can be selected, blocking the outer annulus with a slider. Here we see inside the unit with the slider partially engaged.

Labophot/Optiphot BD episcopic illuminator

This is what it looks like disassembled, with the BD slider exposed.

Labophot/Optiphot episcopic illuminator disassembled Labophot/Optiphot episcopic illuminator disassembled Labophot/Optiphot episcopic illuminator disassembled Labophot/Optiphot episcopic illuminator disassembled Labophot/Optiphot episcopic illuminator disassembled collector lens

And here it is looking through the brightfield side (left) and darkfield (right).

Labophot/Optiphot episcopic illuminator disassembled BF Labophot/Optiphot episcopic illuminator disassembled DF

Some units do not have irises, but have slots for 25 mm filters.

Labophot/Optiphot episcopic illuminator with no iris diaphragms Labophot/Optiphot episcopic illuminator with no iris diaphragms

And here is one with a field diaphram, but the end is broken off, leaving the aperture stop, but with no way to actuate it.

Labophot/Optiphot episcopic illuminator with a broken end Labophot/Optiphot episcopic illuminator with a broken end

Some of them are set up to accept a fiber light.

Labophot/Optiphot episcopic illuminator with fiber light port Labophot/Optiphot episcopic illuminator with fiber light port

The epi illuminator for the Model S is very small, but has apertures and a slide-in, slightly rotatable, polarizer. The slider on the right in the last two photos is the beamsplitter, so it may be removed for diascopic illumination. I think that this unit has a lens, which makes it appear to be 160 mm tube length, so 160/0 or 160/- would be the common objective type here.

Model S episcopic illuminator with lamp Model S episcopic illuminator with lamp Model S episcopic illuminator with lamp Model S episcopic illuminator with lamp

For epi-fluorescence, there has to be a place for a dichroic beamsplitter with excitation and emission filters, as well as a beam block. In the Diaphot, the cube is in the body of the microscope, and the light is injected from the back through the episcopic illuminator.

Diaphot epi-fluorescence illuminator Diaphot epi-fluorescence illuminator with mercury arc lamp Diaphot epi-fluorescence illuminator with mercury arc lamp

For epi-fluorescence on Labophot and Optiphot models, a special illuminator is used that has slots for two cubes (or four for the Quadfluor), as well as built in ND filters and an iris, as well as the beam block. Some units have a place for a polarizer slider at the top (in the emission path), and some lack this feature.

Labophot epi-fluorescence illuminator Labophot epi-fluorescence illuminator Labophot epi-fluorescence illuminator

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