SU1052856A1 - Interference device for gauging dimensions of part - Google Patents

Abstract

INTERFERENTIAL DEVICE FOR MEASURING DETAIL SIZES containing a two-beam Michelson-type interferometer including a monochromatic light channel and a white light channel, receiving units installed at the output of the channels, and an electronic processing unit, characterized in that, in order to improve the accuracy and performance of the measurement, it is equipped two plane-parallel plates with translucent reflective coatings on surfaces facing each other, located in the white light channel perpendicular to but its axes and are movable along this axis. (L 8 ate u 00 ate

Description

FIG.

The invention relates to a measurement technique and can be used in optical interference devices for precision and on-line measurements of parts in various areas of machine design.

An optical interference measurement device for measuring terminal measures containing two plane-parallel plates with an end measure between them is known. The size of the terminal measures in this device is determined by measuring the length of a Fabry-Perot standard formed by two plane-parallel plates with translucent reflective coatings facing each other surfaces The measurement is made by the method of coincidence of the fractional parts of the strips with the consecutive illumination of the plates with the light of several lengths of corn G 1,

The Lank device provides high measurement accuracy, but requires a highly skilled operator and is difficult to automate.

The closest to the proposed technical entity is an interference device for measuring the dimensions of parts, which contains a Michelson-type two-beam interferometer, including a monochromatic light channel and a white light channel (Receiver units installed at the channel entrance, and an electronic processing unit 2,

The weighing device has low measurement accuracy and performance.

The purpose of the invention is to increase the fineness and productivity of the measurement

The goal is achieved by the fact that an interference device for measuring the dimensions of parts containing a Michelson-type dual-beam interferometer, including a monochromatic light channel and a white light channel, receiving units installed at the channel output, and an electronic processing unit, are equipped with two plane-parallel semitransparent reflective coatings on surfaces facing each other, located in a channel of white light perpendicular to its axis with the possibility of moving along this axis . .

FIG. 1 is a schematic diagram of an interference device for measuring the dimensions of parts in FIG. 2 monochromatic and white light signals

The device contains a Michelson-type two-beam interferometer with a monochromatic light channel, including a monochromatic light source 1 and a moving reflector 2, and a white light channel including a white light source 3 and a fixed reflector 4, a beam splitter 5 in the form of a glass cubic scanning system 6, plane-parallel plates 7 and 8 with. Semitransparent reflective coatings on surfaces facing each other, located in a channel of white light perpendicular to its axis with the possibility of moving along this axis receiving units installed at the outlet channel comprising n receiving-usilitenye paths 9 and 10 and the formers 11 and 12 11mpu; lsov and an electronic processing unit 13

As reflectors 2 and 4 use cat-like reflectors.

In FIG. 2, the following is indicated: L, is the difference in travel between the central maximum and the first side in the white light channel signal; the number of pulses of a monochromatic channel on the difference of the course C; P is the number of pulses of the clock generator from the output of the peak of the main maximum of the white light channel signal to the first pulse of the monochromatic channel of the P2 radiation; the number of pulses of the clock generator from the moment of the peak of the first side maximum to the MOTvjeHTa (Rd + 1) th pulse of the monochromatic channel; Yar- length ox / laaepa.

The device for measuring the dimensions of the parts works in the following way.

The interferometer in the initial position has a small negative delay, i.e. the movable reflector 2 is somewhat closer to the beam splitter 5 than the fixed reflector 4. The plane-parallel plates 7 and 8 are mutually parallel and perpendicular to the beam of white light. The frequency of the clock generator (not shown) in the electronic processing unit 13 and the cKOpcjcTb scanning of the movable reflector 2 is set so that during the time of scanning the path difference Lr / 2, the clock generator output is about 100 pulses, t e. .

Two plane-parallel plates 7 and 8 with translucent reflections and Coatings on facing surfaces are a multi-beam Fabry-Perot interferometer. Continuous continuous spectrum of the source 3

light, the passage through such an interferometer is regularly modulated in amplitude as a function of the wave numbers so that the distances () between adjacent maxima, the distance d (cm) between the plates and the path difference and between the central maxima and the first side in the interferogram of the Michelson interferometer, Related Dependency:

L 2dncos Ss-f / dd,

where n is the refractive index of the medium between the reflective surfaces of plazstin 7 and 8 b is the angle of refraction of the rays

in the environment.

Provided un 1, d l / 2 / so t.y2. Thus, determine J, i.e. the size of the part is 14, either by calculating the conversion of the interferogram into a spectrum, or by measuring t by the interferogram. The second way requires significantly less hardware costs and calculations. The scanning system 6 moves the MOVING reflector 2 evenly. With a zero path difference, the signal (Fig. 2) of the white light channel reaches a maximum and at this moment the pulse shaper 11 generates a pulse through which the clock generator pulses in the electronic processing unit 13 begin to flow to one counter (not shown), and the pulses from the imaging unit 12, which were processed through Lr / 2 when the signal of the monochromatic channel passes through the zero level, to the second counter (not shown). The pulses of the clock generator cease to flow to the first counter at the moment of arrival of the first pulse generated by the electronic unit 13. The first counter records the number of points. (The scanning system b continues to move the movable reflector 2. When the path difference reaches 1, the white light channel signal appears the first side maximum at which the pulse shaper 11 generates a pulse, according to which the number Hjj is recorded on the second counter, and the pulses from the clock generator start to flow to the first counter subtraction until

the appearance of (front + 1) th pulse. The first / vi counter has a value of lp (). The processing electronic unit 13 determines the distance between the plates 7 and 8 by the expression

() Lr / 4

After receiving from the imaging unit 12 (PD + 1) -th 1 megapulse, a command is generated to return the movable reflector 2 to the initial state and the device is ready for repeated or new measurement. Measurement can be made

and during the return stroke of the rolling reflector 2.

Reflectors 2 and 4 are selected for the cat's eye type to reduce the requirements for translational movement of the movable reflector 2 during scanning. FIG. 1 shows a double-path interferometer circuit, which makes it possible to double the path difference with the same

moving the movable reflector 2.

five

With relative measurements, the size of the measured part 14 can be significantly larger due to this construction of the part holder when the contact parts (clamps) (not

0 shown) are located much wider than the plane-parallel plates 7 and 8.

The direct counting method of the number of bands is more efficient than the method of coincidence of the fractional parts of the bands. The advantages of the proposed device are the automation of precision measurements, the simplicity of optical

0 device diagrams. The ability to work with extremely narrow beams of light makes it possible to reduce the requirements for the technology of manufacturing optical components. Due to the wide

5 of the purpose of the device, which allows measuring the dimensions of opaque parts and the thickness of transparent plates in a contactless way, the device can be widely used in various areas of mechanical engineering and the optical industry, which allows organizing mass production with unification of components and elements.

Claims (1)

INTERFERENCE DEVICE FOR MEASUREMENT OF SIZES OF PARTS, containing a two-beam Michelson type interferometer, including a monochromatic light channel and a white light channel, receiving units installed at the output of the channels, and an electronic processing unit, characterized in that, in order to increase the accuracy and performance of the measurement, it is equipped with two plane-parallel plates with translucent reflective coatings on facing each other surfaces located in the channel of white light perpendicular to it B and movable along this axis. FIG. 7