SU1578471A1 - Optronic profilometer - Google Patents

Abstract

This invention relates to instrumentation technology. The purpose of the invention is to improve the accuracy due to a more accurate determination of the energy center of the light spot. The profilometer consists of a source of radiation 1, an interferometer formed by a beam splitter 3 and angular reflectors 4 and 5, a two-area photodetector 11 and a drive 13. The beam offset caused by a change in the surface inclination of the object under test is compensated by the movement of the photodetector 11 under the action of the actuator 13 according to signals from the photoreceiver 11 The motion of the photodetector is measured using an interferometer. 2 Il.

Description

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The invention relates to instrumentation technology and can be used to measure the shape of reflective surfaces.

The purpose of the invention is to improve the accuracy by more accurately determining the energy center of the light spot.

FIG. 1 is a block diagram of a profilometer; in fig. 2 is a diagram of a computing unit.

The profilomer consists of optically coupled radiation source 1, light detectors 2 and 3, corner reflectors 4 and 5, a beam splitter 6, and photodetectors 7 and 8, optically, associated with a beam splitter 2 mirrors 9 and 10, and a photodetector 11, circuit 12 tracking the beam electrically connected with the outputs of the photoreceiver 11, the actuator 13, electrically connected with the output of the circuit 12 and mechanically connected with the photoreceiver 11, the computing unit 14, whose inputs are connected to the outputs of the photodetectors 7 and 8, respectively, of the recording unit 15 which first entry It is connected to the output of unit 14, unit 16 for moving the monitored object, the output of which is connected to the input of unit 15. The angular reflector 5 is mechanically connected to the photodetector 11. The photodetector 11 is intended for optical communication with the monitored object through the splitter 2 and the mirror 9 and 10 p is made two-site. The beam splitter 3 and corner reflectors 4 and 5 are installed on the Michelson interferometer.

Computing unit 14 is made of comparators 17 and 18, the outputs of which are the inputs of block 14, vibrators 19 and 20, the inputs of which are connected to the outputs of comparators 17 and 18 connected in series to inverter 37, whose input is connected to the output of comparator 18 and monovibrator 21 Inverter 22 connected in series, the input of which is connected to the output of comparator 17 and monovibrator 23, AND 24 circuits, whose inputs are connected to the outputs of monovibrator 20 and inverter 22, respectively, AND 25 circuits, whose inputs are connected to the outputs of monovibrator 21 and com Arathor 18, AND circuit 26, whose inputs are connected to outputs monovibratora 19 and comparator 17, the AND circuit 27 whose inputs koto

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the swarm is connected to the outputs of the monovibrator 23 and inverter 37, And 28 circuits, the inputs of which are connected to the outputs of the monovibrator 20 and the comparator 17, And 29 circuits, whose inputs are connected to the outputs of the monovibrator 21 and inverter 37, respectively, And 30 circuits, whose inputs are connected to the outputs monovibrator 19 and inverter 22, circuit AND 31, the inputs of which are connected to the outputs of monovibrator 23 and comparator 18, circuit OR 32, the inputs of which are connected to the outputs of circuits AND 24-27, circuit OR 33, whose inputs are connected to the outputs of circuits 28-31, reversible counter 34, the inputs of which are connected to the outputs of the OR circuits 32 and 33, respectively, and of the serially connected digital-to-analog converter 35, the input of which is connected to the output of the counter 34, and the arithmetic unit 36, the output of which is the output of the block 14.

Opto-electronic profilometer works as follows.

A change in the surface tilt of the object being monitored causes a change in the position of the beam in the plane of the photodetector 11. Signals from the photodetector 11} corresponding to the beam displacement are processed in circuit 12. The signal from circuit 12 drives 13 to compensate for the beam displacement by moving the photodetector 11. The movement of the photodetector 11 is measured using an interferometer formed by the beam splitter 3 and the corner reflectors 4 and 5, the signals from the output of which are fed to the photodetectors 7 and 8. The signals from the photodetectors 7 and 8 are fed to the inputs of block 14, to tory calculates a surface profile of the controlled object. The surface profile is recorded by block 15.

Computing unit 14 operates as follows.

The input to the comparators 17 and 18 sinusoidal phase-shifted by / ii / 2 voltage is converted into a sequence of rectangular pulses U and U {. Inverters 37 and 22 are inverted. The voltages at the outputs of the inverters 37 and 22 are denoted by U and Ui, respectively. Vibrators 20, 21, 19 incoming to the montage are rectangular impulses ig,, U, U {with their front edges forming short rectangles

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impulses 0 / U 2, 0 / U. ,, 0 / UZ, 0 / U, G From these pulses, using eight circuits AND 24-31 and two circuits OR 32 and 36, pulse sequences are formed corresponding to an increase and decrease in the radius of the object being monitored by algorithms

U. (0 / U2 A U) V- (0 / U 1A U,) V V (0 / U2AU,) V ();

U - (0 / U2AU,) V (0 / U, AU2) Y (0 / U2 AU,) V (0 / U, A ua).

One of these signals is fed to the summing, and the second to the subtracting input of the reversible counter 34. The digital signal at the output of the reversing counter 34 is converted by a digital-to-analog converter 35 to an analog signal. Last in arithmetic

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com block 36 is converted by the appropriate algorithm into the value of the current deviation of the profile of the object being monitored,

Claims (1)

Invention Formula An optical-electronic profilometer containing a radiation source and a coordinate-sensitive photodetector intended for optical communication with a radiation source through a controlled surface is about the same, so that, in order to improve accuracy, it Equipped with a series-connected tracking circuit for a beam electrically connected with a photodetector, and a photodetector moving drive, a beam splitter and a displacement interferometer optically coupled to a radiation source through a beam splitter, and cho interferometer mechanically associated with a photodetector.