Modulation Contrast Method - Nikon ECLIPSE TS100 Instructions Manual

Modulation Contrast Method

6
1
Modulation Contrast (NAMC) System
The Modulation Contrast System offers you a stable relief image which can well be compared to
the differential interference contrast microscopy (DIC microscopy). But, unlike the DIC
microscopy, you can observe the specimen inside the plastic containers since this system does
not require its illumination to be polarized.
The Modulation Contrast System for the TS100 series is made up of two components; a pattern
called "modulator" (placed at the back focal plane of the NAMC objective) and a slit diaphragm
(to be installed in the NAMC slider). (The NAMC system for the TS100 series is a fixed contrast
system and thus a polarized plate is not used.)
Modulators (objectives) and slit diaphragms come in pairs. Check that the NAMC codes (NAMC1,
NAMC2 or NAMC3) displayed on both the modulator and the slit diaphragm are the same before
using. Note that a correct image cannot be obtained if the NAMC codes do not match.
2
Principles of Modulation Contrast
Since human eyes, cameras, and films capture objects by perceiving differences in light intensity
and/or color, they cannot see (or sense) the colorless, transparent cells or bacteria. These
colorless transparent objects are called "phase objects" since they only change the phase of the
light when the light passes through them.
The phase objects can be made visible by dyes, but their life will be deprived. In order to
observe the living phase objects, differential interference contrast and phase contrast
microscopy are invented, and modulation contrast microscopy likewise. The modulation contrast
microscopy adopts the same optical system as the ordinary microscopes, but with some
additional parts that convert the transparent specimen into the variation of light intensity. These
additional parts modulate the amplitude of the light that passed through the specimen, thus
changing the intensity of the light making up the visible image.
(In differential interference contrast and phase contrast microscopy, the phase objects are
converted into the variations of light intensity by the phase change that occurs when the light
passes through the specimen.)
Let's now think of a light that passes through a specimen. Since a phase object has the different
refractive index as its surroundings, the light will be refracted at its border. (See figure 1
showing refracted light on trapezoidal phase object.) The same thing happens to every
specimen.
4 Operation of Each Part
6 Modulation Contrast Method
Fig. 1
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