JPH02159504A - Coordinates measuring apparatus - Google Patents

Abstract

PURPOSE:To achieve a smaller size of the apparatus as a whole, an expansion of a measuring range and a reduction in errors by arranging first-third beam dividers and a reflecting mirror comprising at least double rectangular trihedron mirrors and mounted on a contractor or a measuring table. CONSTITUTION:In a laser interferometer 12, a laser light 18 emitted from a light source is divided into a transmission light 28 and a reflected light 30 with a beam splitter 20 and the transmission light 28 is made to irradiate a reflector 17 on an object to be measured to be turned to a reflected transmission light 28A in inversion and incident into a beam splitter 22 to be divided into a transmission light 28A' and reflected light 28A''. A position detector 32 as two-split photodiode for detecting a bearing of an object to be measured is arranged on an extension of the transmission light 28A to control a bearing of the interferometer. Then, the reflected lights 30 and 28A'' are incident into a beam splitter 24 to interfere and the number of interference fringes are counted with a control section 26 to measured a distance between the interferometer 12 and the object to be measured. The control section 26 computes and displays coordinates of the object to be measured with a data processor based on data of dimensions obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coordinate measuring device, and particularly to a coordinate measuring device using a laser interferometer.

[Conventional technology]

In general, laser interferometers have been introduced and used in various fields such as length measuring instruments and displacement measurement systems that can measure length and the like in microns by taking advantage of their accuracy.

FIG. 6 is a diagram showing the principle of a conventional laser interferometer.

The laser interferometer shown in FIG. 6 includes a laser light source 50 that emits laser light, a beam splitter 52, a movable reflector 54 installed on the object to be measured, a reference reflector 56, and reflections from the movable reflector 54 and the reference reflector 56. and a display unit (not shown) that counts the interference fringes obtained by the light and displays the amount of movement t[+ of the movable reflecting mirror.

The emitted laser light 58 is optically split by a beam splitter 52 to become reflected light 60 and transmitted light 62.

The transmitted light 62 is then reflected by the moving movable reflecting mirror 54 and sent to the beam splitter 52 again.

The reflected light 60 reflected by the reference reflecting mirror 56 is superimposed on the transmitted light 62 reflected by the movable reflecting mirror 54 at the beam splitter 52 to form interference fringes. The interference fringes are photoelectrically converted into electrical signals by a photodiode or the like, the number of interference fringes is counted, and the amount of movement of the movable reflecting mirror 54 is displayed on the display section.

Further, as the movable reflecting mirror 54 installed on the object to be measured, a right-angled three-sided prism, a cat's eye prism, or a right-angled three-sided mirror 64 shown in FIG. 7 has been used.

When using a laser interferometer in a two-dimensional coordinate measuring device, the laser interferometer is placed at each of the 2' reference points on the surface plate, and the laser beam emitted from each laser interferometer is attached to a probe. The distance from each interferometer to the object to be measured is measured. Since the distance between the two laser interferometers is determined in advance, the coordinates of the object to be measured are measured based on this data.

[Problem that the invention seeks to solve]

However, since a conventional coordinate measuring device using a laser interferometer requires a reference reflector, the entire device becomes large and space efficiency deteriorates.

In addition, the laser beam irradiation range of the conventional three-sided right-angled mirror 64 (
The measurable range) is as shown in FIG.
If the direction of 4 is not changed, ±20° to ± from the front.
The range is 25°. Two reference points are required for a two-dimensional coordinate measuring device (three for a three-dimensional coordinate measuring device), so as shown in FIG. There is a problem that the measurable range 690 of 68 overlaps with the measurable range 70, and the coordinate measurement range is extremely narrow.

Further, when the above-mentioned three-sided right-angled mirror 10 is used, there is a drawback that errors cannot be reduced.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coordinate measuring device that can reduce the size of the entire device, has a wide coordinate measuring range (and has few errors).

[Means for solving problems]

In order to achieve the above object, the present invention combines a laser beam emitted from a laser light source into a first transmitted beam and a first transmitted beam perpendicular to the first transmitted beam.
a first beam splitter that splits the reflected light into a first beam splitter; a reflector that reflects the first transmitted light, which is made up of at least two sets of right-angled three-sided mirrors and is attached to a probe or measurement table; a second beam splitter into which the first transmitted light reflected by the mirror enters and splits the first transmitted light into a second transmitted light and a second reflected light perpendicular to the second transmitted light; A third beam splitter, into which the light and the second reflected light are incident, interferes with the first reflected light and the second reflected light, and a third beam splitter that counts interference fringes and measures and displays the amount of movement of the reflecting mirror. It is characterized by comprising a control section that performs the following functions.

[Effect]

According to the present invention, a laser beam is split into a first transmitted light and a first reflected light by a first beam splitter, and the first transmitted light is sent to a reflector attached to a probe or a measuring table. The beam is irradiated and reflected, and this first reflected light is made to enter a third beam splitter.

Further, the first transmitted light reflected by the movable reflecting mirror is made incident on the second beam splitter, and the second transmitted light and the second transmitted light are made to enter the second beam splitter.
and the reflected light. The second reflected light enters the third beam splitter and is superimposed on the second reflected light to generate interference fringes. In this way, since no reference mirror is used, the structure of the optical system is simplified and the laser interferometer can be downsized.

Furthermore, the reflecting mirror for the coordinate measuring device consists of at least two sets of right-angled three-sided mirrors. Therefore, when measuring coordinates, laser light is irradiated from each interferometer onto a separate three-sided right-angled mirror, the resulting interference fringes are counted and the distance is measured, and the coordinates are calculated based on that data. This makes it possible to expand the measurable range of coordinates and to perform measurements with fewer errors.

〔Example〕

Hereinafter, preferred embodiments of the coordinate measuring device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a first embodiment of a coordinate measuring device according to the present invention. The main body of the measuring unit of the three-dimensional coordinate measuring device IO shown in Fig. 1 includes three laser interferometers 12 installed at each reference point. 14. Probe 16 that measures the shape, dimensions, etc. by contacting the object to be measured;
Reflector 17, moving mechanism 19 in the X-axis, Y-axis, and Z-axis directions.
The main components are 21 and 23.

FIG. 2 is a diagram showing the principle of the laser interferometer 12. As shown in FIG. 2, the laser interferometer 12 includes one laser light source (not shown) that emits a laser beam 18, a first beam splitter 20 that forms interference fringes, a second beam splitter 22,
It is composed of an optical system consisting of a third beam splitter 24 and a control section 26 that counts interference fringes.

1 on the optical axis of the laser beam 18. A first beam splitter 20 is provided that splits the light 18 into a first transmitted light 28 and a first reflected light 30 orthogonal thereto. The first transmitted light 28 is irradiated onto the reflecting mirror 17 of the object to be measured, and the first reflected light 30 is guided to the third beam splitter 24 disposed on the front axis thereof.

The first transmitted light 28 is reflected by the reflecting mirror 17, and becomes reflected transmitted light 28Δ, which returns to the first transmitted light 28 and the flat surface]. Second Bee! - The splitter 22 is arranged along the optical axis of the reflected light 28A, and converts the reflected transmitted light 28A into a second transmitted light 28Δ.
', and a second reflected light 28A# that enters the third beam brick 24 orthogonal thereto.

Furthermore, a two-part photodiode position detector 32 for detecting the orientation of the object to be measured is installed on the extension line of the reflected and transmitted light 28A, and controls the orientation of the interferometer 12.

The first reflected light 30 and the second reflected light 28A' interfere with each other at the third beam splitter 24, and the number of interference fringes is counted by the control unit 26, and the distance between each interference group 12 and the object to be measured is is measured. Based on the obtained data of each dimension, the control unit 26 uses a data processor (not shown) or the like to
Calculate the coordinates of the object to be measured]7 Display.

According to the laser interferometer described above, since there is no need to use a beam mirror, the laser interferometer 4 can be made smaller.
It is possible to simplify the structure of the optical system.

FIG. 3 is a perspective view of the reflecting mirror 17 used in the three-dimensional coordinate measuring device IO according to the present invention. The reflecting mirror 17 in Fig. 3 is constructed by standing mirrors 34, 36 formed in an L-shaped surface and double-sided mirrors 38, 40 perpendicular to the L-shaped surface to form two sets of right-angled three-sided mirrors. A set of 4 right angles 3 with a pair of right angle three-sided mirrors
It forms a mirror. Reflector 117 is disposed on probe 16 and moves according to the movement of probe 16. During measurement, each of the 12 laser interferometers irradiates each of these three right-angled mirrors with laser light separately, so the measurable range is expanded. Then, while bringing the tip of the probe 16 into contact with an object to be measured (not shown) placed on the ruler 14, the probe 16 is
The shape, dimensions, etc. of the object to be measured are calculated based on the coordinate data of each measurement point.

FIG. 4 is a perspective view showing a second embodiment of the coordinate measuring device according to the present invention. The three-dimensional coordinate measuring device IL! shown in Figure 1. :
The difference is that the probe 42 is of a fixed type. A measurement table 44 having moving mechanisms 43, 45, 47 in the X-axis, Y-axis, and Z-axis directions is arranged below the probe 42 fixed to the support column 41, and the object to be measured is placed on this measurement table 44. I'm trying to post it. Therefore, during measurement, the fixed probe 42 is brought into contact with the object to be measured on the measurement table 44, and the object to be measured is moved together with the measurement table 44 to obtain data for each dimension. Calculating the shape, dimensions, etc. of the object to be measured based on these data is the same as in the first embodiment. Furthermore, as a unique effect of the second embodiment, the laser beam emitted from the laser interferometer 12 is not blocked by the shape of the object to be measured, so there is no need to pay attention to the laser beam during measurement. (Become.

FIG. 5 is a perspective view of a reflecting mirror 46 used in a two-dimensional coordinate measuring device, in which a double-sided mirror 50 is erected perpendicular to a mirror 48 formed in an L-shape to form two right-angled three-sided mirrors. is forming. In a two-dimensional coordinate measuring device, two laser interferometers are used, and each laser interferometer irradiates each right-angled three-sided mirror with laser light. Accordingly, as the irradiation range is expanded, the coordinate measurement range for the object to be measured can be expanded.

In the two-dimensional coordinate measuring device, the reflecting mirror 46 may be fixed on a surface plate, and the laser interferometer may be arranged on a moving table or a probe.

〔Effect of the invention〕

As explained above, according to the coordinate measuring device according to the present invention, since a laser interferometer that does not use a reference reflector is used, the entire coordinate measuring bag device can be downsized, and space efficiency is improved. do. Furthermore, since the laser beams emitted from each laser interferometer are reflected by separate reflecting mirrors, the measurable range is expanded, and measurement errors can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first embodiment of the coordinate measuring device according to the present invention, FIG. 2 is a principle diagram of a laser interferometer used in the coordinate measuring device according to the present invention, and FIG. 3 is a perspective view showing the first embodiment of the coordinate measuring device according to the present invention. FIG. 4 is a perspective view of a second embodiment of the coordinate measuring device according to the present invention, FIG. 5 is a perspective view of the reflector according to the present invention, and FIG. 6 is a perspective view of a conventional laser interference device. FIG. 7 is a perspective view of a conventional reflecting mirror, and FIGS. 8 and 9 are explanatory diagrams of the conventional reflecting mirror. lO...Three-dimensional coordinate measuring device, 12...Laser interferometer, 14...Surface plate, 16...Boo lobe, 17...Reflector, 18...Laser light, 19
... X-axis moving mechanism, 20... First beam splitter, 21... Y-axis moving mechanism, 22... Second beam splitter, 23... Z-axis moving mechanism,
24...Third beam splitter, 26...
Control unit, 28...first transmitted light, 28A...reflected light, 28A'...second transmitted light, 288'...
Second reflected light, 30...First reflected light, 34.3
6.48... L-shaped mirror, 38.40.50... Double-sided mirror, 42... Fixed probe, 43... X-axis movement mechanism, 44... Measurement table, 45... Y-axis Movement mechanism, 46...2 right-angled three-sided mirror, 47...Z-axis movement mechanism.

Claims (1)

[Claims] (1) A first beam splitter that splits the laser light emitted from the laser light source into a first transmitted light and a first reflected light perpendicular to the first beam splitter, and at least two right-angled three-sided mirrors. or a reflecting mirror attached to a measurement table that reflects the first transmitted light; the first transmitted light reflected by the reflecting mirror is incident, and the first transmitted light is orthogonal to the second transmitted light; a second beam splitter which splits the reflected light into a second reflected light; a third beam splitter into which the first reflected light and the second reflected light enter and which interferes with the first reflected light and the second reflected light; A coordinate measuring device comprising: a beam splitter; and a control unit that counts interference fringes and measures and displays the amount of movement of a reflecting mirror.