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Phase contrast set pzo
The phase contrast set PZO consists of the following parts:
The Phase contrast condensor PZO K3PhZ with numerical aperture of 1.2 and following positions:
The condenser looks absolutely flawless with no scratches, no dust, no fungus, no fingerprints. Phase rings are completely OK
* perfectly functioning aperture iris diaphragm
* fully rotating polarization filter with degree scale and markers for crossed and parallel polarizers
* the corresponding second polarizers are located right in the phase plate.The condenser is centered with two screws from the bottom.
* the individual phase screens are individually centered
* the condenser has the usual barrel diameter of 39.5 mm and fits almost all microscopes from PZO, Zeiss Jena, Lomo but also to other brands. Overall height is approximately 23 mm.
* 4 pieces of phase contrast objectives apparently never used in the original plastic container with PZO logo on the lid:
10 / 0.24 PHZ 160 / - PZO Poland
20 / 0.4 PHZ 160 / 0.17 PZO Poland
40 / 0.65 PHZ 160 / 0.17 PZO Poland
100 / 1.3 OI PHZ 160 / 0.17 PZO Poland ( oil immersion)
* All the lenses have standard RMS thread, with about 20 mm in diameter and are standardized according to DIN matching length of 45 mm, designed for the mechanical tube length from 160 mm that is also now common
"Mainly two types of phase-contrast devices are used: positive (Zernike type) and negative.
The positive phase contrast (Zernike) is more suitable for observation of objects that strongly refract the light, amplitude-phase objects, i.e. objects of an intermediate character between amplitude and phase objects, and is also more suitable for observation of structures with a refraction index smaller than that of the surroundings. Furthermore, in a microscope with positive phase contrast (Zernike type) pictures are obtained that resemble to a high degree those observed in a normal microscope, in a light field after dyeing of the preparation which facilitates the identification and differentiation of details.
A negative phase contrast shows generally a greater sensitivity, i.e. enables to detect in the preparation smaller differences in the optical path, provides a greater contrast and a more plastic picture. In a negative phase contrast the background of the picture is dark.
Most firms manufacture both positive phase-contrast devices of the Zernike type and negative phase-contrast devices, but this does not yet fully satisfy all needs connected with the observation of objects that have no natural contrast. The Polish Optical Works manufacture besides the positive phase-contrast device KF of the Zernike type and the negative phase-contrast device KFA with phase rings of soot, two new ones: the positive phase-contrast device KFS with dielectric - soot rings, and the phase device with variable contrast KFZ. The KF device has the features of the mentioned positive phase-contrast device of the Zernike type whereas the KFA device shows the features of the a.m. negative phase-contrast. The KFS device has the same advantages and range of application as the KFA type; moreover, it produces a stronger contrast picture which may be desirable for making photographs of microobjects. In view of the positive type of the contrast, pictures seen with the KFS device hove a light background with dark details -similar to pictures observed in light field.
Special attention merits the phase device KFZ with variable contrast. It enables observation both in positive contrast of the Zernike type and in negative contrast KFA, and also provides the possibility of quick and smooth transit from one to the other. Besides these operational advantages the KFZ device produces a stronger contrast picture with better differentiation of details and more sensitive than normal equipment.
DESIGN OF PHASE-CONTRAST EQUIPMENT
The full set of phase-contrast equipment manufactured by the Polish Optical Works comprises the following:
* positive phase device, Zernike type, KF,
* negative phase device, KFA,
* positive phase device, KFS,
* phase device with variable contrast, KFZ."
