SU1290124A1 - Focometer - Google Patents

Abstract

The invention relates to optical instrumentation and improves the accuracy and reduces the time of a single measurement. At an angle of 45 to the optical axis of the device, a rod mirror 7 of rectangular shape is installed with rotation, in the focal plane of which the photodetector 9 is installed. built in front of the focal plane fS

Description

1290

The bone of the auxiliary lens 8 or behind it (depending on the sign of the optical power of the system 6). By rotating the mirror 7, the beam traces are alternately directed to the photodetector 9, starting or turning off the pulse counter of the standard frequency generator of the meter 11 time intervals. Time information

one

The invention relates to optical instrumentation and is intended to measure the focal lengths of optical systems.

The aim of the invention is to improve the measurement accuracy and reduce the time of a single measurement.

The drawing shows a schematic diagram of the focus meter.

The photometer consists of a source of light 1, a condenser 2, a collimator consisting of lens 3, in the front focal plane of which a slit diaphragm is installed, an opaque diaphragm 5 with two slots parallel to the slit of the collimator, a controlled optical system 6, a rotating mirror 7 the lens 8, the first 9 and second 10 photodetectors, the first P and the second 12 time interval meters and the digital scaler 13.

In the drawing, the designation: traces of 14 and 15 narrow beams of rays in the rear focal plane of the auxiliary lens.

Phocometer works as follows.

The collimator lens 3 forms a wide parallel beam of rays, from which the slits of the opaque aperture 5 cut two narrow parallel beams of rays. In the absence of a controlled system, the auxiliary lens builds an image of the slit 4 in its rear focal plane. When a controlled optical system 6 is introduced into the course, the image of the slit 4 is constructed by an equivalent optical system 6-8 before drawing.

The paths of the beam traces are output by a digital scaler 13. The execution of the angular velocity sensor in the form of a second photodetector 10 connected to the second meter at 12 time intervals eliminates the influence of the instability of the rotation of the mirror 7 on the measurement results. 1 z.p, f-ly, 1 ill.

depending on the sign of the optical power of the monitored system 6, and in the focal plane of the auxiliary lens traces of narrow beams of rays are built. The angles are oL and equal. The distance a and the angle are known, the focal distance of the controlled system 6 is defined as

2 tg - When the mirror 7 rotates, the traces of narrow beams of rays are shifted along the back focal plane relative to the first photodetector 9. When a light signal hits the photoreceiver from trace 14, the pulse counter of the standard frequency generator of the first meter starts 11 time intervals, and when it hits the photoreceiver 9, the light signal from trace 15 is terminated by the generator pulses. Information about the number of pulses is fed to the first input of the digital scaler. In addition, information about the frequency of the generator, the angular rotational speed of the mirror and the distance a is fed into the digital scaler. In it, the running time of the traces of the beam of rays in front of the first photo-receiver 9 is determined by the number of pulses and the frequency of the generator. The angle p is determined this time and the time of one revolution, and then f. Information is provided by a digital display, a digitizer or a Fit or Scrap actuator.

312

To eliminate the effect of the instability of the speed of rotation of the mirror 7 on the measurement results, the angular velocity sensor is designed as follows. In the rear focal plane, a second driver 10 is mounted, which is associated with a second time interval meter. When a light signal from the trace 14 hits the photodetector, a standard-frequency pulse generator starts up. When the light signal from the trace 15 hits, the electric pulse does not enter the system. The counting of pulses ceases when the light signal from trace 14 hits the photodetector 10 again. The angular velocity of rotation of the mirror is determined by the number of pulses and the generator frequency (time of one revolution).

Claims (2)

1. A photometer containing a light source and a condenser located along the beam on one side of the monitored system, a collimator consisting of a lens and a slit diaphragm installed in its front focal plane, a diaphragm with two slits parallel to the aperture of the collimator, and another Editor A.Lezhnina From the State S.Sokolov Tehred L.Oleinik Order 7891/37 Circulation 799 Subscription VNSHPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4 O five one 50 five 0 244 side of the monitored system is an auxiliary lens, characterized in that, in order to increase accuracy and reduce the time of a single measurement, it is additionally equipped with a flat rectangular mirror mounted at an angle of 45 ° to the optical axis with the possibility of rotation between the monitored system and the auxiliary lens, in the focal plane of which the first photodetector is installed, the output of which is connected to the input of the first time interval meter, and its output is connected to the first input additionally ennogo digital scaler, and the angular velocity sensor measuring the rotational mirror with the second meter timeslots. 2. The Pok.1 fokometer, characterized in that, in order to improve measurement accuracy by eliminating the effect of mirror rotation instability, the mirror rotation speed sensor includes a second photodetector, the output of which is connected to the input of the second time meter, the output of which is connected with the second input of a digital scaler. Proofreader T. Kolb