Olympus BHM Metallurgical Trinocular Microscope

Olympus BHM Metallurgical Trinocular Microscope

With Original Manual
Serial: 306025
With Olympus TL4 Light Source

Objectives:
IC10 ULWD MSPLAN 10
IC20 ULWD MSPLAN 20
IC25 ULWD MSPLAN 25
IC50 ULWD MSPLAN 50


Many microscopes are designed to be modular—that is they can be
converted for different types of microscopy by simply changing a few parts.
The requirements for metallurgical microscopes are so dramatically
different from other microscopes, however, that manufacturers generally
produce special dedicated metallurgical microscopes,
rather than have modules available to convert other instruments.

Metallurgical microscopes are designed for
observation of the surfaces of (usually) opaque materials.
Thus there is absolutely no need for the optically complex
sub stage illumination system present on other microscopes.
However, these instruments must have an equally complex epi illumination system.

The special illumination system needs to be built so that the
light can be sent either directly down the objective or through
light channels surrounding the objective to give the epi illumination equivalent
of bright field and dark field illumination respectively.
These instruments always produce a somewhat "washed out" image with
bright field illumination, because the illuminating beam is
passing through the same lens that is used for observation.
The lenses thus need to be both high quality and clean!
This same type of optical arrangement is commonly used for
fluorescence microscopy, except here the wavelength that is used for
excitation is removed by filters in the microscope head, so this problem does not arise.

The intensity of the light source need not be much brighter than for standard microscopy. Most modern instruments use quartz halogen illumination.

Metallurgical microscopes still need a stage—but it normally can be a simple solid metal plate. However, because it is often necessary to place thick specimens on the stage, the stage needs to be adjustable so that it can be moved up and down on the focusing rack and pinion. (The Olympus BHM is designed to work this way.)