JPH0612243B2 - Coordinate measuring device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a coordinate measuring device, and more particularly to a coordinate measuring device using a laser interferometer.

[Conventional technology]

Generally, a laser interferometer has been introduced and used in various fields such as a length measuring device and a displacement measuring system capable of measuring the length and the like in units of microns by utilizing its accuracy.

FIG. 6 is a principle diagram of a conventional laser interferometer. The laser interferometer shown in FIG. 6 includes a laser light source 50 that emits a laser beam, a beam splitter 52, a movable reflecting mirror 54, a reference reflecting mirror 56, a movable reflecting mirror 54 and a reference reflecting mirror 5 that are installed on the object to be measured.
The display unit (not shown) that displays the moving amount of the movable reflecting mirror by counting the interference fringes obtained by the reflected light from 6

The emitted laser light 58 is optically split by the beam splitter 52 to be reflected light 60 and transmitted light 62.
Then, the transmitted light 62 is reflected by the moving movable reflecting mirror 54 and is sent to the beam splitter 52 again.

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

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

When a laser interferometer is used in a two-dimensional coordinate measuring apparatus, laser interferometers are arranged at two reference points on a surface plate, and laser light emitted from each laser interferometer is attached to a tentacle. It is reflected by the movable reflecting mirror 54, and the distance from each interferometer to the object to be measured is measured. Since the distance between the two laser interferometers is predetermined, the coordinates of the object to be measured are measured based on these data.

[Problems to be solved by the invention]

However, the coordinate measuring apparatus using the conventional laser interferometer needs a reference reflecting mirror, and thus has a drawback that the entire apparatus becomes large and space efficiency deteriorates.

Further, the laser light irradiation range (measurable range) of the conventional right-angled three-sided mirror 64 is ± 20 ° to ± from the front when the direction of the right-angled three-sided mirror 64 is not changed as shown in FIG.
It is in the range of 25 °. In the case of a two-dimensional coordinate measuring device, two reference points (three in a three-dimensional coordinate measuring device) are required,
As shown in FIG. 9, the overlapping portion of the measurable range 67 of the two laser interferometers 66 and the measurable range 69 of the laser interferometer 68 becomes the measurable range 70, which causes a problem that the coordinate measurement range is very narrow. is there.

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

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a coordinate measuring device that has a small size as a whole and has a wide coordinate measurable range and a small error.

[Means for solving problems]

In order to achieve the above object, the present invention provides a laser light emitted from a laser light source with a first transmitted light and a first transmitted light orthogonal to the first transmitted light.
A first beam splitter for splitting the first transmitted light into a reflected light and a reflecting mirror for reflecting the first transmitted light, which is attached to a contactor or a measurement table, the reflecting mirror being composed of at least two series of right-angled three-sided mirrors; A second beam splitter that receives the reflected first transmitted light and splits the first transmitted light into a second transmitted light and a second reflected light that is orthogonal to the second transmitted light; The second reflected light is incident, and the first reflected light and the second reflected light
It is characterized by comprising a third beam splitter for interfering with the reflected light of and the control unit for counting the interference fringes and measuring and displaying the moving amount of the reflecting mirror.

[Action]

According to the present invention, the laser beam is split into the first transmitted light and the first reflected light by the first beam splitter, and the first transmitted light is applied to the reflecting mirror attached to the contactor or the measurement table. Then, the first reflected light is made incident on the third beam splitter.

In addition, 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 reflected.
And the reflected light of. The second reflected light enters the third beam splitter and is superimposed on the second reflected light to generate interference fringes. As described above, since the reference mirror is not used, the structure of the optical system is simplified and the laser interferometer can be downsized.

Further, the reflecting mirror for the coordinate measuring device is composed of at least two series of right-angled trihedral mirrors. Therefore, at the time of coordinate measurement, laser light is emitted from each interferometer to a separate right-angled three-sided mirror, the obtained interference fringes are counted, the distance is measured, and the coordinates are calculated based on the data. can do. As a result, the coordinate measurable range can be expanded, and measurement with less error is possible.

〔Example〕

Hereinafter, preferred embodiments of a coordinate measuring apparatus 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 the coordinate measuring device according to the present invention. The main body of the measuring unit of the three-dimensional coordinate measuring apparatus 10 shown in FIG. 1 has three laser interferometers 12, ... (Probe) 16 for performing measurement of the object, reflecting mirror 17, X-axis, Y-axis and Z-axis direction moving mechanisms 19, 2
1 and 23 are the main components.

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

The laser light 18 is passed through the first transmitted light 2 on the optical axis of the laser light 18.
8 and a first reflected light 30 orthogonal to the first
The beam splitter 20 is provided. First transmitted light 2
8 is irradiated on the reflecting mirror 17 of the object to be measured, and the first reflected light 30 is guided to the third beam splitter 24 arranged on the optical axis thereof.

The first transmitted light 28 is reflected by the reflecting mirror 17 and becomes reflected / transmitted light 28A, which is parallel to the first transmitted light 28.
The second beam splitter 22 is arranged on the optical axis of the reflected light 28A and converts the reflected transmitted light 28A into the second transmitted light 28A '.
And the second reflected light 28A ″ that is incident on the third beam splitter 24 orthogonal to this.

Further, on the extension line of the reflected / transmitted light 28A, a position detector 32 of two-division photo diode for detecting the azimuth of the object to be measured is installed to control the azimuth of the interferometer 12.

Then, the first reflected light 30 and the second reflected light 28A ″ interfere with each other at the third beam splitter 24, the number of interference fringes is counted by the controller 26, and the distance between each interferometer 12 and the DUT is measured. Based on the obtained data of each dimension, the control unit 26 uses a data processor (not shown),
Calculate and display the coordinates of the DUT.

According to the laser interferometer described above, since it is not necessary to use the reference mirror, the laser interferometer can be downsized and the structure of the optical system can be simplified.

FIG. 3 is a perspective view of the reflecting mirror 17 used in the three-dimensional coordinate measuring apparatus 10 according to the present invention. In the reflecting mirror 17 of FIG. 3, double-sided mirrors 38 and 40 orthogonal to the L-shaped surface are erected on the mirrors 34 and 36 formed on the L-shaped surface to form two right-angled three-sided mirrors.
The two sets of right-angled three-sided mirrors are paired to form four collective right-angled three-sided mirrors. The reflecting mirror 17 is arranged on the probe 16 and moves according to the movement of the probe 16. At the time of measurement, each of these right-angled three-sided mirrors is individually irradiated with laser light from each laser interferometer 12, so the measurable range is expanded. Then, the probe 16 is moved while bringing the tip of the probe 16 into contact with an object to be measured (not shown) placed on the surface plate 14, and the shape, dimensions, etc. of the object to be measured are calculated from the coordinate data at each measurement point.

FIG. 4 is a perspective view showing a second embodiment of the coordinate measuring device according to the present invention. The difference from the three-dimensional coordinate measuring apparatus 10 of FIG. 1 is that the probe 42 is fixed. Post 41
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 table 42, and an object to be measured is placed on the measurement table 44. I have to. 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. The shape, size, etc. of the object to be measured are calculated based on these data as in the first embodiment. Further, as a peculiar effect of the second embodiment, since the laser light emitted from the laser interferometer 12 is not blocked by the shape of the object to be measured, it is not necessary to pay attention to the laser light during the measurement.

Further, FIG. 5 is a perspective view of a reflecting mirror 46 used in a two-dimensional coordinate measuring apparatus, in which a double-sided mirror 50 orthogonal to a mirror 48 formed on an L-shaped surface is erected to form two right-angled three-sided mirrors. Is forming. In the two-dimensional coordinate measuring apparatus, two laser interferometers are used and each laser interferometer irradiates each right-angled three-sided mirror with laser light. As a result, the coordinate measurable range for the object to be measured can be expanded as the irradiation possible range is expanded.

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

〔The invention's effect〕

As described above, according to the coordinate measuring device of the present invention, since the laser interferometer that does not use the reference reflecting mirror is used, it is possible to reduce the size of the entire coordinate measuring device and improve the space efficiency. . Further, since the laser light emitted from each laser interferometer is reflected by a separate reflecting mirror, the measurable range can be expanded and the measurement error can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a coordinate measuring apparatus according to the present invention, FIG. 2 is a principle diagram of a laser interferometer used in the coordinate measuring apparatus according to the present invention, and FIG. FIG. 4 is a perspective view of the reflecting mirror, FIG. 4 is a perspective view showing a second embodiment of the coordinate measuring apparatus according to the present invention, FIG. 5 is a perspective view of the reflecting mirror according to the present invention, and FIG. 6 is a conventional laser interference. FIG. 7 is a perspective view of a conventional reflecting mirror, and FIGS. 8 and 9 are explanatory views of the conventional reflecting mirror. 10 ... Three-dimensional coordinate measuring device, 12 ... Laser interferometer,
14: surface plate, 16: probe, 17: reflector, 1
8 ... 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, 28A "... second reflected light, 30 ... first reflected light, 34, 36, 48 ... L-shaped mirror, 38, 40,
50 ... Double-sided mirror, 42 ... Fixed probe, 43 ... X-axis moving mechanism, 44 ... Measuring table, 45 ... Y-axis moving mechanism, 46 ... Double right-angled three-sided mirror, 47 ... Z-axis moving mechanism.

 ─────────────────────────────────────────────────── ─── Continuation of the front page Examiner Yasuko Eto (56) References JP-A-61-97504 (JP, A)

Claims (1)

[Claims] 1. A at least two series of right-angled three-sided mirrors, which are arranged on an object to be measured, which is movable in a two-dimensional plane or in a three-dimensional space, and which respectively reflect incident laser light in the same direction as the incident direction. A movable interferometer, and two or more laser interferometers, which are arranged at different positions and respectively measure the amount of movement of the movable interposition,
Two or more having detection means for entering the reflected light reflected by the movable reflector and detecting the incident position thereof, and control means for controlling the emission direction of the laser light based on the detection position of the detection means Laser interferometer, and a calculation means for calculating the coordinate position of the measured object on a two-dimensional plane or in a three-dimensional space based on each measurement value of each laser interferometer, measuring device.