SU1428969A1 - Photometer - Google Patents

Abstract

The invention relates to optical instrument making and allows increasing the measurement accuracy and extending the range of the measured focal length in the direction of decreasing. The carriage 7 with the photoreceiver 9 is perpendicular to the optical system. The photodetector 9 intersects the traces of the narrow beams of the source 1 rays. During one of the movements of the carriage after the element to be monitored, a plane-parallel plate 14 of known thickness is established. The sensor 10 of the carriage movement amount 7 is connected via the information processing unit 11 with the display unit. J з.п f-ly, 1 ill. (at

Description

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9 7

114

The invention relates to an optical instrument making device, namely to the field of optical measurements, and is intended to deflect by contactless focal distance optical elements.

The purpose of the invention is to reduce the measurement time, increase accuracy, reduce size, automate the measurement process and extend the range from: 1 fi x X focal length.

A: iia drawing e presents the principle of the focus meter,

; The phometer consists of a source of 1 phyte, condenser 2. of a collimator, which is made of volume 3, in the irregular focal plane of which a diaphragm A is mounted, the second bottom 5 with two apertures, the shape of an identical diaphragm hole 4 Monitored optical element B of the carriage 7, moving perpendicular to the optical axis of the system using an electric motor 8, a coordinate photoreceiver 9, a carriage displacement magnitude sensor 10, an information processing unit 11 (digital scaler) 5 of the display unit 12, CTF melting device

13 and thick plane-parallel plate

14.

 works as follows.

Fotosprnemnik 9 dvalkdy intersects beam beams The first rides of the narrow carriage displacement with the photodetector are produced in the absence of a thick plane-parallel groove 14 in the course of the rays and the distance is determined. Then the plate is installed and the second passage of the carriage is determined by the distance b. The distance between the measurement planes is early for the elongation of the rays of the plane-parallel plate, i.e.

, 1 (n -1)

H -

one

TREATMENT OF THREE TREE;

and is the refractive index of the glass plate.

The focal distance is determined by the expression

I -

TO

2a1 (p-1)

where K is the coefficient ,, characterizing a specific focus meter. When using a focometer, the measurement error of the focal lengths in the range of 200-10000 mm according to the calculated data does not exceed 0.1% at a time of one measurement in the order of 10 ... 15 s. The measurement process can be fully automated. Possible documentary issuance of information. Fokometers can work in control and screening complexes.

Claims (2)

1.Fokometr, including a light source, a condenser, a collimator made of a lens and a diaphragm placed in its front focal plane, a second diaphragm with two apertures, made symmetrically with respect to the optical axis in a form identical to the aperture of the collimator aperture, and behind the controlled element is a measuring unit, characterized in that, in order to increase the accuracy of measurement and expand the range of measured - the focal length in the direction of decreasing, the measuring unit is made in the form of a coordinate photodetector installed in front of the focal plane of the element under test in the plane, perpendicular to second optical axis, with its movable by the actuator along a line parallel to the line connecting the centers of the holes of the second diaphragm, connected to the computing means, and a plane-parallel plate of known thickness, adapted to outputting. 2.Fokometr nqn.l, characterized in that, in order to automate the measurement process, the drive is made in the form of an electric drive, and the computing means is made in the form of a displacement amount sensor, the first input of which is connected to the output of the photodetectors 5 of the information processing unit connected to the second input displacement amount sensor and a display unit connected to the output of the displacement amount sensor.