SU68919A1 - Visibility meter - Google Patents

Description

The proposed visibility meter, based on the principle of veiling the observed image with some variable brightness, allows various observations to be made against the background of the same visible brightness.

According to the invention, the meter is provided with a single fixed pigonal prism located in front of the lens and a turning (one or two) sector-shaped diaphragm screen located near it.

FIG. 1 shows the optical system of the proposed meter; FIG. 2 and 3 are the rotary diaphragm entering this system and in FIG. 4 and 5 double diaphragms of the modified device.

The telescopic system of the meter (Fig. 1) is formed by the lens 7 and the ocular 2.

Near the lens there is a stationary and a pygranous prism 3 and a rotatable sector-shaped screen and diaphragm 4, which has the shape of a semicircle. The center of the semicircle, which is the center of rotation of the diaphragm, lies on the optical axis of the system; the optical axis intersects the edge G of shrism 3 (Figs. 1 and 2).

18 Code in. 7

The readings give the angle of rotation of the diaphragm relative to the position at which the edge of the diaphragm 4 coincides with the edge G of the prism 3 (Fig. 2 and 3). The device gives two images.

In the variant of the proposed meter, instead of one rotary sector-shaped diaphragm 4, two sector-like square diaphragms 5 and b (Figs. 4 and 5) are also used, of which one (5) is stationary, while the second (6) is able to turn around the optical axis of the system.

Subject invention

The visibility meter, based on the principle of veiling the observed image with some variable brightness, is characterized in that it is equipped with one fixed focal prism located in front of the lens and a pivot near it (one or two) a sector-shaped screen-diaphragm.

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FIG. I

FIG. 3

FIG. 2

FIG. four

FIG. five