JP5250286B2 - Tracking laser interferometer - Google Patents

Description

  The present invention relates to a tracking type laser interferometer, and more particularly to a tracking type laser interferometer having a simple configuration and capable of performing high-precision measurement without affecting the reference sphere support part.

  As described in Patent Document 1, as illustrated in FIG. 1, a reference sphere 10 that serves as a measurement reference, a reference sphere support 12 that supports the reference sphere 10, and a periphery of the reference sphere 10 are divided into two. A revolving mechanism 20 including a first axis rotating mechanism 21 and a second axis rotating mechanism 22 that rotate in a shaft, and a laser interference length measuring machine 30 mounted on the rotating mechanism 20, and a target recursion The target is tracked based on the information of the return light from a retroreflector (retroreflector) 40 (for example, a cat's eye) 40, and the laser interference length measuring machine 30 mounted on the rotation mechanism unit 20 is based on the center coordinates of the reference sphere 10. 2. Description of the Related Art A tracking type laser interferometer that measures a distance between a light beam emitted from a light beam and a retroreflector 40 in which the optical axes of return light beams are parallel is known. In the figure, 14 is a fixed base.

  Similar tracking laser interferometers (also referred to as optical axis deflection laser interferometers) are also described in Patent Documents 2 to 4.

  In this type of tracking laser interferometer, the rotation mechanism unit 20 is rotated so that the deviation between the optical axes of the emitted light and the return light becomes a predetermined value (or amount) or a desired value (amount), thereby causing laser interference. The length measuring device 30 is directed toward the retroreflector 40, and the distance from the interference state between the outgoing light and the return light at that time to the retroreflector 40 is measured with high accuracy.

  In this tracking type laser interferometer, the motor 23 and the laser interferometer length measuring device 30 of the second axis rotation mechanism 22 are arranged on the rotation side of the first axis rotation mechanism 21, so that various signal wirings 50 and motor wirings 52 are provided. It is necessary to guide the fiber line 54 and the like from the rotation side to the fixed side (fixed base 14).

German patent application DE202004007647U1 Japanese Patent Laid-Open No. 63-231286 JP 2007-309677 A JP 2007-057522 A

  As shown in FIG. 1, when the signal wires 50, the motor wires 52, and the fiber wires 54 on the rotation side are directly wired to the fixed side (fixed base 14), the rotation mechanism 20 rotates. As shown in FIG. 1, the wiring goes out of the device, the workability when working around is bad, the wiring interferes with other devices, etc. There is a problem that the wiring shields the laser beam emitted to the target (retroreflector 40).

  On the other hand, a method of passing the wiring through the space inside the apparatus and guiding the wiring to the fixed side can be considered. According to this method, since the wiring is not performed outside the apparatus, the above problem does not occur. However, even in this method, since the rotation mechanism unit 20 rotates, it is necessary to set various wires to a sufficient length, and the wires arranged in the space move, and the wires are connected to the reference sphere support unit 12. The direct contact and the tension and frictional force due to the wiring act on the reference ball support portion 12. Then, since the reference sphere support 12 is deformed, the reference sphere 10 moves. The force due to this wiring is not reproducible and is very difficult to manage. Further, this tracking laser interferometer measures the distance between the target (retroreflector 40) and the reference sphere 10 while the rotation mechanism 20 rotates around the reference sphere 10, so that the measurement is performed when the reference sphere 10 moves. The reference moves and the measurement accuracy decreases.

  Another method that can supply an electric signal in both directions of the fixed side and the rotating side is a slip ring. If this slip ring is used, the fluctuation of the reference sphere is eliminated. However, since the slip ring transmits a signal by the contact between the rotating ring and the brush, there is a problem of a decrease in signal S / N and a problem of maintenance. In addition, since tracking laser interferometers require various signal transmissions, the slip ring is large, the space is required, the device is large, the cost is high, and there are many occurrences such as crosstalk. Issue arises.

  The present invention has been made to solve the above-described conventional problems, and an object thereof is to eliminate the influence of wiring to the reference sphere support portion with a simple configuration and to enable high-precision measurement.

The present invention provides a fixed base , a reference sphere that serves as a reference for measurement, a reference sphere support section that is disposed on the fixed base that supports the reference sphere, and rotates around the reference sphere in two axes. a rotation mechanism comprising a second axis turning mechanism rotatably disposed in the first axis turning mechanism and said uniaxial rotation mechanism on which is rotatably disposed on the fixed table, said rotary mechanism The laser interferometer is mounted on the laser and tracks the target based on the information of the return light from the recursive reflector as the target, and the laser mounted on the rotation mechanism section with reference to the center coordinates of the reference sphere in the tracking type laser interferometer in which the optical axis of the outgoing light and return light from the interferometer length measuring machine measures a distance between the recursive reflector formed of parallel, an inner peripheral portion of the first axis turning mechanism is a hollow, the hollow, tubular cover is provided through the gap between the reference sphere supporting portion, the outer cylindrical cover Between the inside of the first axis turning mechanism, as the wiring from the fixing base to the second axis turning mechanism and the laser interferometer length measuring machine passes, it is obtained by solving the above problems.

Here, the cylindrical cover may be doubled so that the wiring from the fixed base to the second shaft rotating mechanism and the laser interference length measuring instrument passes through the space inside the cylindrical cover. it can.

  According to the present invention, it is possible to perform high-accuracy measurement with low-cost parts without the influence of tension or frictional force caused by contact of various wirings, optical fibers, or the like with respect to the reference sphere support. In addition, since the wiring does not protrude largely outside the apparatus, the work space is expanded and interference with other apparatuses is eliminated, so that highly reliable measurement is possible. Furthermore, compared with the slip ring, since the wiring is wired, there is no crosstalk or signal deterioration between various signals, no maintenance is required, and highly reliable signal transmission is possible.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The first embodiment of the present invention is a tracking laser interferometer similar to that shown in FIG. 1, and is a tracking laser interferometer of the type in which the outer peripheral portion 21A of the first shaft rotating mechanism 21 rotates as shown in FIG. The inner peripheral portion 21B of the first shaft rotation mechanism 21 installed in the base portion (fixing base 14) of the apparatus is made hollow, the reference ball support portion 12 is provided in the hollow, and the outer peripheral portion has a desired And a distance between the surface of the reference sphere 10 and the laser interference length measuring device 30 is set outside the second shaft rotation mechanism 22, the laser interference length measuring device 30 installed on the rotation side. The motor line / various signal lines 70 and the fiber line / various signal lines 72 from the displacement meter 32 to be measured are passed through and guided to the connector 80 on the fixed base 14 side.

  Here, the first axis rotation mechanism 21 rotates in the azimuth direction by horizontal rotation, and the second axis rotation mechanism 22 rotates in the elevation direction.

  The displacement meter 32 is for measuring the distance between the surface of the laser interferometer 30 and the reference sphere 10 as described in Patent Document 4 to enable high-precision measurement.

  In this embodiment, with respect to the rotation of the first rotating shaft mechanism 21 in the azimuth direction, a play of wiring is provided at the cylindrical cover 60 installed in the hollow of the inner peripheral portion 21B (by wrapping around the cylindrical cover, etc.) Provide play), processed inside. Further, a play is made at a portion outside the wiring, corresponding to the rotation of the second shaft rotation mechanism 22 in the elevation direction.

  According to the present embodiment, even if the rotation mechanism unit 20 rotates and various wirings move within the hollow space, the wiring contacts the cylindrical cover 60, so that the friction and tension of the wiring affects only the cylindrical cover 60. give. Therefore, the reference sphere support 12 is not affected by the wiring, and the reference sphere 10 is not changed.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In the present embodiment, the present invention is applied to a tracking type laser interferometer in which the inner peripheral portion 21B of the first shaft rotating mechanism 21 rotates, and the outer peripheral portion 21A of the first shaft rotating mechanism 21 is attached to the fixed base 14. Since it is the same as that of 1st Embodiment except the point fixed, description is abbreviate | omitted.

  Next, a third embodiment of the present invention will be described with reference to FIG.

  This embodiment is a double-structured cylindrical cover 62 in which the cylindrical cover is also provided on the first shaft rotating mechanism 21 side in the second embodiment.

  According to this embodiment, the contact of the wiring with the rotating part can be reliably prevented.

  In any of the above embodiments, as with the tracking laser interferometer described in Patent Document 4, a displacement meter 32 is provided to measure the distance between the surface of the laser interferometer 30 and the reference sphere 10. High-precision measurement is possible. The displacement meter 32 may be omitted depending on the application.

  In the above embodiments, the driving and guiding methods are omitted, but there are various belts, friction, direct motor methods, etc. for driving, rolling bearings, air bearings, etc. for guiding, but the methods are limited. Not what you want. The cross-sectional shape of the cover is not limited to a circle, and may be another shape such as an ellipse or a rectangle.

Sectional view showing the prior art described in DE202004007647U1 Sectional drawing which shows 1st Embodiment of this invention Sectional drawing which similarly shows 2nd Embodiment Sectional drawing which similarly shows 3rd Embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Reference sphere 12 ... Reference sphere support part 20 ... Rotation mechanism part 21 ... 1st axis | shaft rotation mechanism 22 ... 2nd axis | shaft rotation mechanism 30 ... Laser interference length measuring machine 40 ... Retro reflector 60, 62 ... Cylindrical cover 70, 72 ... wiring

Claims (2)

A fixed base, a reference sphere which forms a reference of measurement, supporting the reference sphere, the fixed bench disposed a reference sphere supporting portion, biaxially rotational motion around the reference sphere, the fixing base A rotation mechanism portion comprising a first shaft rotation mechanism rotatably disposed on the first shaft rotation mechanism and a second shaft rotation mechanism rotatably disposed on the first shaft rotation mechanism, and mounted on the rotation mechanism portion Have a laser interferometer,
The target is tracked based on the information of the return light from the recursive reflector as a target, and the light emitted from the laser interference length measuring machine mounted on the rotation mechanism unit and the light of the return light with reference to the center coordinates of the reference sphere. In a tracking laser interferometer that measures the distance to a retroreflector whose axes are parallel,
The inner peripheral portion of the first axis turning mechanism and a hollow,
In the hollow, a cylindrical cover is provided via a gap with the reference sphere support,
A tracking type laser characterized in that wiring from the fixed base to the second axis rotation mechanism and the laser interference length measuring instrument passes between the outside of the cylindrical cover and the inside of the first axis rotation mechanism. Interferometer. The cylindrical cover is doubled, and wiring from the fixed base to the second shaft rotation mechanism and the laser interferometer is passed through a space inside the cylindrical cover. 2. The tracking type laser interferometer according to 1.

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