User Guide

490 Series Microscope
AmScope Proprietary Page 59 of 64
Immersion Oil
A special oil used with the 100X objective to concentrate the light and increase
the resolution of the image. At high magnifications the field of view is so small
that very little light passes. The light refracts, scatters and produces a dark
image.
A drop of oil is placed on the slide’s cover slip and the objective is lowered until
it touches the oil. The oil will match the specimen’s light refracting index to the
lens, adding more light to the specimen, which improves resolution and clarity.
Interpupillary Distance
Interpupillary Distance is the distance between your eyes. AmScope uses 2 types of
systems to change interpupillary distance.
Siedentopf heads adjust the interpupillary distance by rotating the
eyetubes around a central axis. A Siedentopf head changes the
interpupillary distance without changing the tube distance.
Jentsch heads adjust the interpupillary distance by moving the
eyetubes closer together or farther apart in a linear fashion. The
tube length changes when changing interpupillary distance, so the
user compensates by adjusting the focus of the eyepieces to
correspond to the new interpupillary distance.
Iris or Diaphragm
The diaphragm or iris is located under the stage and is an
apparatus that can be adjusted to vary the intensity, and
size, of the cone of light that is projected through the slide.
The iris adjustment slider allows you to adjust the opening of
the iris.
Lenses
Microscopes have a two lens system, objective and ocular.
The Objective Lens is the lens closest to the specimen or object.
The Ocular Lens (Eyepiece) is the lens closest to the eye.