SU110537A1 - Polarization binocular visibility meter - Google Patents

Description

The subject of the invention is a device intended for use primarily in the field of lighting engineering and masking.

The described device belongs to the most common group of visibility meters, in which visibility is reduced to threshold 1 by an arbitrary decrease in the contrast of the object and the background.

Successful use of any visibility meter in lighting, masking, and a number of other areas is possible only if the visual perception conditions do not significantly change in the process of measuring visibility.

The peculiarity of the proposed device is that it uses an optical system, consisting of a double-refractive lens, a prism and a polaroid, and a single relative one.

FIG. 1 shows the optical scheme of a polarization binocular visibility meter; in fig. 2nd kinematic scheme.

The effect of the proposed visibility meter is based on the optical combination of the object and the background that occurs when the object is sighted through a birefringent prism 1.

Bringing the contrast of the object and the background to the threshold is achieved by quenching one of the two plane-polarized images of the object by rotating the polaroid 2 relative to the birefringent prism / or rotating the prism / relative to the polaroid 2.

If the contrast between the object and the background is reduced to a threshold value from the maximum angle of the polaroid, then, as the photometric calculation shows, the visibility V, defined as the ratio of the actual contrast of the object and the background K to the threshold contrast S, is equal to:

TO

cos

The design of the polarization visibility meter allows you to rotate the prism 1 and the polaroid 2 relative to each other, for example by sliding the prism and the polaroid rims, and the angle of rotation is measured, for example, on a scale of connections with one of the optical components of the instrument connected to another optical component of the instrument.

To ensure the spatial perception of objects to be observed, a polarization visibility meter is proposed to be binocular, and to improve the accuracy of the angle of rotation, a kinematic device with a variable gear ratio is used, as shown in FIG. 2

The birefringent prisms / are fixedly mounted on the body of the device, and the floor 2 can rotate 90 ° synchronously, thanks to a pair 3 that connects the frames 4 to the floor, on the left side of the floor there is a pusher 5 sliding along the arc 6. The arc 6, together with the arrow 7, under the action of the pusher 5 rotates on the axis 8. In this case, the gear ratio increases as the pusher approaches the arrow axis.

The system described makes it possible to obtain the instrument chambel {graduated in terms of the visibility values), which is much more equal to the limits of the most frequently occurring visibility values. The arc 6 is constantly pressed against the pusher 5 under the action of the spring 9, which eliminates a backlash when changing the direction of rotation of the floor.

The device, in comparison with the known measuring instruments of visibility, has the following advantages:

1. Adaptation conditions in the process of measuring visibility change, which ensures stability.

2. The optical combination of the object and the background, in order to bring the contrast to the threshold value, does not introduce color distortions, which allows for the correct consideration of color contrasts.

3- The instrument introduces in the central part of the field of view no optical distortions that can affect the level of visibility, and a large field of radiation ensures that the distribution of brightness is unchanged,

which allows one to correctly take into account when measuring visibility the brilliance not only in the central, but also in the peripheral part of the field of vision.

4. The position of the observer's eyes is not fixed relative to the exit pupil of the device or any optical axis, so the measurements do not require precise installation of the device relative to the eyes and do not tire the observer.

5. The instrument, due to its binocularity, makes it possible to measure visibility with regard to the spatial perception of the object.

6. The graduation of a polarization visibility meter in the number of thresholds can be performed not by the quenching method (not sufficiently accurate), but by the angle of rotation of the polaroid of the prism or photometrically-according to the transmittance of polarized light.

Subject invention

Claims (3)

1. A polarization binocular visibility meter, characterized in that, in order to maintain the constancy of the adaptation conditions in the process of measuring the visibility of an object, it uses an optics system consisting of a combination of a birefringent prism and polaroid, turning one with respect to . 2. The form of the visibility meter in p-1, characterized in that, in order to provide the possibility of assessing visibility taking into account the spatial wake of the object, the optical system is binocular. 3. The form of execution of the visibility meter by n. 1, 2, characterized in that, in order to ensure synchronism of the rotation of the polys and fixation of the measured value with greater accuracy, a device in the form of a pairing device, a pusher and an arc transmitting force to the instrument arrow is applied. No. 110537  2 FIG. one