JP7236027B2 - Optical rotating probe and shape measuring device - Google Patents

Description

The present invention relates to an optical rotating probe that irradiates an object to be measured with measuring light and receives the reflected light of the measuring light reflected by the object to be measured, and a shape measuring apparatus that includes this optical rotating probe.

As a shape measuring device for measuring the shape of an object, for example, an optical probe is used to detect the three-dimensional coordinate values of various measurement points on the object without contact, thereby obtaining the shape of the object. Coordinate measuring devices are known. The optical probe irradiates the measurement light from the light source toward the measurement point of the measurement object, and receives the reflected light of the measurement light reflected at the measurement point. Then, the shape measuring device measures the shape of the measurement object based on the result of detecting the distance from the optical probe to the measurement point by a known measurement method using an interferometer.

As such an optical probe, an optical rotary probe capable of rotating and scanning in a direction around the longitudinal axis of the probe is known (see Patent Documents 1 and 2). By performing rotational scanning using an optical rotating probe, for example, it is possible to measure the inner surface shape of a cylindrical measurement object, or simultaneously measure the surface shape of multiple measurement objects placed on a surface plate. can be done.

Patent Document 1 discloses a fixed-side optical fiber cable that guides measurement light from a light source, an optical rotary connector, a rotating-side optical fiber cable connected to the fixed-side optical fiber cable via the optical rotary connector, and a rotating-side optical fiber cable. An optical rotary probe is described that includes an imaging optic located distal to the . In this optical rotary probe, by connecting the fixed-side optical fiber cable and the rotating-side optical fiber cable with an optical rotary connector, the rotating-side optical fiber cable and the imaging optical system can be integrally rotated around the longitudinal axis of the probe. can.

Patent Literature 2 describes an optical rotating probe that is rotatable around the longitudinal axis of the probe by utilizing the slack of the optical fiber cable. This optical rotary probe can be rotated about the longitudinal axis of the probe within the torsional elastic limit of the optical fiber cable.

JP 2015-29567 A WO2010/047190

By the way, in the optical rotary probe described in Patent Document 1, the fixed-side optical fiber cable and the rotary-side optical fiber cable are connected by an optical rotary connector. Here, since a single-mode optical fiber cable is used as the optical fiber cable in the above-described known measurement method using an interferometer, if the rotation accuracy deteriorates due to wear of the optical rotary connector, the light reception sensitivity of reflected light, etc., through the optical rotary probe will be reduced. decreases significantly. A polarization-maintaining optical fiber cable is used as the optical fiber cable for more accurate measurement, but due to its structure, the polarization-maintaining optical fiber cable cannot be connected with an optical rotary connector.

The optical rotary probe described in Patent Document 2 cannot be rotated beyond the torsional elastic limit range of the optical fiber cable, so there is a problem that the number of rotations of the optical rotary probe is limited.

The present invention has been made in view of such circumstances, and provides an optical rotating probe that achieves prevention of a decrease in sensitivity to reflected light, avoidance of restrictions on the number of rotations, and compatibility with polarization-maintaining optical fiber cables, and An object of the present invention is to provide a shape measuring apparatus equipped with this optical rotating probe.

An optical rotary probe for achieving the object of the present invention emits measurement light emitted from a light source toward an object to be measured, and receives the reflected light of the measurement light reflected by the object to be measured. a light guide path for guiding the measurement light and the reflected light, the light guide path having an input/output end from which the measurement light is emitted and the reflected light is incident; a hollow first shaft having a first longitudinal axis parallel to both optical paths of reflected light incident on and a first inner surface surrounding the optical paths; and a shaft rotation mechanism that rotates the first shaft on the side opposite to the side facing the incident/exit end of the first shaft, and reflects the measurement light incident through the inside of the first shaft toward the object to be measured. and a reflector that reflects the reflected light from the object to be measured toward the incident/exit end.

According to this optical rotating probe, the first shaft and the reflector are rotated by the shaft rotating mechanism without rotating the light guide, so that the measurement light can be rotated and scanned with respect to the object to be measured.

An optical rotary probe according to another aspect of the present invention comprises an imaging lens provided inside the first shaft for focusing the measurement light onto the measurement object. Thereby, the measurement light can be focused on the measurement object.

In an optical rotary probe according to another aspect of the present invention, a second hollow shaft inserted inside the first shaft and having a second longitudinal axis parallel to the optical path and a second inner surface surrounding the optical path. It comprises a second shaft and a shaft holding part that holds the second shaft in a non-rotatable direction about the second longitudinal axis, and an imaging lens is provided inside the second shaft. This prevents the optical axis of the imaging lens from moving (vibrating) in the direction perpendicular to the optical path due to the rotation of the first shaft or the like by the shaft rotation mechanism, thereby improving the stability of the optical axis of the imaging lens. can be improved.

In the optical rotation probe according to another aspect of the present invention, the reflector has an exit/incidence surface for emitting the measurement light toward the measurement object and for receiving the reflected light from the measurement object, and An imaging lens is provided and focuses the measurement light onto the measurement object. This makes it possible to use an imaging lens with a short focal length.

In the optical rotary probe according to another aspect of the present invention, a collimator is provided between the incident/exiting end and the first shaft. As a result, it is possible to prevent the light receiving sensitivity of the reflected light from being lowered due to misalignment between the light guide path and the optical system in the first shaft.

In the optical rotating probe according to another aspect of the present invention, a shaft rotating mechanism is provided between the light guide path and the first shaft, and the shaft rotating mechanism has a hollow portion through which the measurement light and the reflected light pass. Thereby, the first shaft can be rotated without blocking the measurement light and the reflected light.

In an optical rotating probe according to another aspect of the invention, the reflector is a rectangular prism mirror.

A shape measuring apparatus for achieving the object of the present invention is a shape measuring apparatus for measuring the shape of an object to be measured, comprising: a light source for emitting measurement light; the optical rotating probe; and an interference signal detection unit that detects an interference signal between the reflected light and the reference light that is a part of the measurement light reflected on a reflecting surface different from the measurement object. This reflective surface includes an outgoing and incoming edge.

INDUSTRIAL APPLICABILITY The present invention can realize prevention of a decrease in the light receiving sensitivity of reflected light, avoidance of rotation speed limitations, and compatibility with polarization-maintaining optical fiber cables.

1 is a schematic diagram of a three-dimensional coordinate measuring device; FIG. FIG. 4 is a cross-sectional view of an optical rotary probe; FIG. 4 is an explanatory diagram for explaining shape measurement of a measurement surface of a work using an optical rotating probe; FIG. 10 is a cross-sectional view of an optical rotating probe of another embodiment 1; FIG. 11 is a cross-sectional view of an optical rotating probe of another embodiment 2;

[Configuration of three-dimensional coordinate measuring device]
FIG. 1 is a schematic diagram of a three-dimensional coordinate measuring device 10 corresponding to the shape measuring device of the present invention. The X-axis, Y-axis, and Z-axis in FIG. 1 are a machine coordinate system defined based on a machine coordinate origin specific to the three-dimensional coordinate measuring apparatus 10.

As shown in FIG. 1, the three-dimensional coordinate measuring apparatus 10 uses an optical rotating probe 26 to measure the shape of a work W, which is the object to be measured in the present invention, for example, to measure the shape of the inner peripheral surface of a cylindrical work W. I do. The shape of the work W here includes the three-dimensional shape, two-dimensional shape, surface shape, contour shape, and various dimensions such as length and diameter of the work W. Moreover, the shape and type of the workpiece W to be measured are not particularly limited.

The three-dimensional coordinate measuring apparatus 10 includes a pedestal 12, a table 14 (surface plate) provided on the pedestal 12, a right Y carriage 16R and a left Y carriage 16L erected on both ends of the table 14, a right Y and an X guide 18 that connects the upper portions of the carriage 16R and the left Y carriage 16L. The right Y carriage 16R, the left Y carriage 16L, and the X guide 18 constitute a portal frame 19. As shown in FIG.

Sliding surfaces on which the right Y carriage 16R and the left Y carriage 16L slide along the Y axis are formed on the upper surface and side surfaces of both ends of the table 14 in the X axis direction. An air bearing (not shown) is provided at a position facing the sliding surface of the table 14 on the right Y carriage 16R and the left Y carriage 16L. As a result, the right Y carriage 16R and the left Y carriage 16L become movable along with the X guide 18 in the Y-axis direction.

An X carriage 20 is attached to the X guide 18 . The X guide 18 has a sliding surface along the X axis direction on which the X carriage 20 slides. Also, the X carriage 20 is provided with an air bearing (not shown) at a position facing the sliding surface of the X guide 18 . This allows the X carriage 20 to move freely in the X-axis direction.

A Z carriage 22 (also referred to as a Z spindle) is attached to the X carriage 20 . The X carriage 20 is also provided with an air bearing (not shown) for guiding the Z carriage 22 in the Z axis direction. Thereby, the Z carriage 22 is held by the X carriage 20 so as to be movable in the Z-axis direction. At the lower end of the Z carriage 22, a measuring head 24 is provided for selectively detachably holding various known probes including an optical rotating probe 26. As shown in FIG.

Although not shown, the three-dimensional coordinate measuring apparatus 10 includes a Y-axis driving unit for moving the portal frame 19 in the Y-axis direction, an X-axis driving unit for moving the X carriage 20 in the X-axis direction, and a Z-axis drive unit that moves the Z carriage 22 in the Z-axis direction. Thereby, the measuring head 24 (optical rotating probe 26) can be moved in three mutually orthogonal axial directions (XYZ axial directions).

A Y-axis linear scale (not shown) is provided at the end of the table 14 on the right Y carriage 16R side. The X guide 18 is provided with an X-axis linear scale (not shown), and the Z carriage 22 is provided with a Z-axis linear scale (not shown).

On the other hand, the right Y carriage 16R is provided with a Y-axis detector (not shown) for reading the Y-axis linear scale. The X carriage 20 is also provided with an X-axis detection section (not shown) and a Z-axis detection section (not shown) for reading the X-axis linear scale and the Z-axis linear scale, respectively. A detection result of each detection unit is output to the control device 72 via the controller 70 .

The measurement head 24 includes a head drive unit (not shown) such as a motor that rotates the optical rotating probe 26 around a rotation axis parallel to the Z-axis and around a rotation axis perpendicular to the Z-axis. ) is provided. Thereby, the measurement head 24 can steplessly adjust the rotation angle of the optical rotary probe 26 in the directions around the two rotation axes. As a result, the posture of the optical rotary probe 26 can be arbitrarily displaced (rotated).

The measuring head 24 is provided with a probe rotation angle detector (not shown) such as a rotary encoder for detecting the rotation angle of the optical rotary probe 26 . A result of detection by the probe rotation angle detection unit is output to the control device 72 via the controller 70 .

The optical rotating probe 26 is detachably attached to the measuring head 24 . The optical rotating probe 26 emits the measurement light LA input from the wavelength swept light source 28 via the optical fiber cable 30 and the fiber circulator 32 toward the measurement surface (here, the inner peripheral surface) of the workpiece W. Further, the optical rotating probe 26 receives the reflected light LB reflected by the measurement surface of the work W, and transmits this reflected light LB and a reference light LC (see FIG. 3) to be described later via the fiber circulator 32 and the optical fiber cable 34. output to the photodetector 36.

Further, although details will be described later, the tip portion (rotating optical system 42, see FIG. 2) of the optical rotating probe 26 is configured to be rotatable around a longitudinal axis 62a (see FIG. 2), which will be described later. . Thereby, the optical rotary probe 26 can rotate and scan the measurement light LA along the measurement surface of the workpiece W by rotating the tip portion thereof.

FIG. 2 is a cross-sectional view of the optical rotary probe 26. As shown in FIG. As shown in FIG. 2, the optical rotary probe 26 includes a fixed optical system 40 fixed to the measurement head 24 and a rotary optical system rotated by the fixed optical system 40 around the longitudinal axis 62a of the optical rotary probe 26. 42 and.

The fixed optical system 40 includes an optical fiber cable 44 , a head mounting portion 46 , a collimator lens 48 and a hollow motor 50 .

The optical fiber cable 44 corresponds to the light guide path of the present invention. As the optical fiber cable 44 (similarly to the other optical fiber cables 30 and 34), various known optical fiber cables such as a single mode optical fiber cable and a polarization maintaining optical fiber cable are used.

One end of the optical fiber cable 44 is inserted through the measurement head 24 and the Z carriage 22 and connected to the fiber circulator 32 . Also, the other end side of the optical fiber cable 44 is connected to the head mounting portion 46 . The end surface of the optical fiber cable 44 on the other end side emits the measurement light LA input from the wavelength sweeping light source 28 via the optical fiber cable 30 and the like, and the reflected light LB and the like reflected by the measurement surface of the workpiece W enters. It becomes the input/output end 44a. The symbol P in the drawing indicates the optical path of the measurement light LA and the reflected light LB.

Part of the measurement light LA input from the wavelength swept light source 28 or the like to the optical fiber cable 44 is reflected as the reference light LC (see FIG. 3) at the incident/output end 44a. Therefore, the incident/output end 44a also functions as a reflecting surface of the present invention.

The head mounting portion 46 is a hollow cylinder extending in a direction parallel to the optical path P (longitudinal axis 62a). One end of the head attachment portion 46 is detachably attached to the measurement head 24 described above. A hollow motor 50 is fixed to the other end of the head mounting portion 46 . Further, one end side of the head attachment portion 46 is provided with a cable connection portion 46a to which the other end side of the optical fiber cable 44 is connected. The cable connecting portion 46a holds the input/output end 44a of the optical fiber cable 44 inside the head mounting portion 46 at a position that coincides (including substantially coinciding with) the central axis of the head mounting portion 46. As shown in FIG.

The collimator lens 48 is provided inside the head mounting portion 46 and at a position between the incident/output end 44 a and the hollow motor 50 . The optical axis of this collimator lens 48 coincides with the center line of the optical path P. As shown in FIG. The collimator lens 48 converts the measurement light LA emitted from the incident/exit end 44a into parallel light, and then emits the measurement light LA toward an imaging lens 64 in a shaft 62, which will be described later. As a result, it is possible to prevent a decrease in the light receiving sensitivity of the reflected light LB caused by misalignment between the fixed optical system 40 and the rotating optical system 42 . Also, the collimator lens 48 emits the reflected light LB incident from the imaging lens 64 toward the incident/exiting end 44a.

The hollow motor 50 corresponds to the shaft rotation mechanism of the present invention, and rotates a shaft 62, which will be described later, in a direction around its longitudinal axis 62a (hereinafter simply referred to as a direction around the longitudinal axis). The hollow motor 50 includes a hollow stator 52 (also called a stator) formed by winding a coil (not shown), and a hollow rotor 54 (also called a rotor) rotating inside the stator 52 in the direction around the longitudinal axis. And prepare. Since the detailed structure of the hollow motor 50 is a well-known technology, the detailed description thereof will be omitted.

The rotor 54 is formed with a hollow portion 54a through which the optical path P passes and extending in a direction parallel to the optical path P (longitudinal axis 62a). As a result, the measurement light LA emitted from the collimator lens 48 passes through the hollow portion 54a and enters an imaging lens 64, which will be described later, and the reflected light LB emitted from the imaging lens 64 passes through the hollow portion 54a. Incident into the collimator lens 48 .

The rotor 54 rotates about the longitudinal axis 62 a in response to application of a drive signal (voltage) to the stator 52 from the controller 70 . The hollow motor 50 is provided with a rotor rotation angle detector (not shown) such as a rotary encoder that detects the rotation angle of the rotor 54 . A detection result by the rotor rotation angle detection unit is output to the control device 72 via the controller 70 . Instead of using the rotor rotation angle detection unit, the rotation angle of the rotor 54 may be detected by controlling the rotation angle of the rotor 54 by, for example, known servo control.

A shaft holding plate 60 that constitutes the rotating optical system 42 and will be described later is fixed to the annular distal end surface 54 b of the rotor 54 facing the rotating optical system 42 .

The hollow motor 50 is not limited to the configuration (structure) shown in FIG. 2, and various known hollow motors may be used instead.

The rotating optical system 42 rotates around the longitudinal axis in accordance with the rotation of the rotor 54 . The rotating optical system 42 includes a shaft holding plate 60 , a shaft 62 , an imaging lens 64 and a rectangular prism mirror 66 .

The shaft holding plate 60 is formed in substantially the same shape (annular shape) as the tip surface 54b of the rotor 54, and is fixed on the tip surface 54b in a posture parallel to the tip surface 54b. The shaft holding plate 60 is formed with a fitting hole through which the optical path P passes and extending in a direction parallel to the optical path P (longitudinal axis 62a). One end of the shaft 62 is fitted into this fitting hole. As a result, the shaft holding plate 60 holds the shaft 62 with its longitudinal axis 62a aligned with the centerline of the optical path P. As shown in FIG.

The shaft 62 corresponds to the first shaft of the invention. The shaft 62 is a hollow cylinder extending in a direction parallel to the optical path P, and has a longitudinal axis 62a (corresponding to the first longitudinal axis of the present invention) parallel to the optical path P. In a state in which one end of the shaft 62 is fixed to the shaft holding plate 60, the longitudinal axis 62a coincides (substantially coincides) with the center line of the optical path P, and the inner surface 62b of the shaft 62 (first inner surface of the present invention). ) surrounds the optical path P.

An imaging lens 64 is provided inside the shaft 62 and at the other end of the shaft 62 opposite to the one end described above. A rectangular prism mirror 66 is provided at the other end of the shaft 62 so as to cover the opening on the other end side of the shaft 62 .

The imaging lens 64 is arranged at a position where its optical axis coincides with the centerline of the optical path P. As shown in FIG. The imaging lens 64 forms an image of the measurement light LA incident from the collimator lens 48 on the measurement surface of the workpiece W through the rectangular prism mirror 66 . Also, the imaging lens 64 emits the reflected light LB incident through the rectangular prism mirror 66 toward the collimator lens 48 .

The rectangular prism mirror 66 corresponds to the reflector of the present invention, and reflects the measurement light LA incident through the inside of the shaft 62 and the imaging lens 64 toward the measurement surface of the workpiece W. Specifically, the rectangular prism mirror 66 refracts the measurement light LA incident from the imaging lens 64 by 90° (including approximately 90°) to form a plane of rotation of the rectangular prism mirror 66 or the like [longitudinal axis 62a (rotational axis). surface perpendicular to], and then emitted toward the surface of the work W to be measured.

Also, the rectangular prism mirror 66 reflects the reflected light LB reflected by the measurement surface of the workpiece W toward the imaging lens 64 . As a result, the reflected light LB passes through the collimator lens 48 from the right-angle prism mirror 66 and enters the incident/output end 44 a of the optical fiber cable 44 .

The shaft holding plate 60, the shaft 62, the imaging lens 64, and the rectangular prism mirror 66, which constitute the rotating optical system 42, integrally rotate around the longitudinal axis as the rotor 54 rotates. Then, the rectangular prism mirror 66 is rotated around the longitudinal axis, so that the measurement light LA is rotationally scanned along the measurement surface of the workpiece W. As shown in FIG.

Returning to FIG. 1, when the three-dimensional coordinate measuring apparatus 10 is in the manual measurement mode, the controller 70 controls each drive unit (not shown) (XYZ drive unit and head drive unit) according to an operation input to an operation unit (not shown). ) is driven to displace the position and posture of the optical rotating probe 26, and the hollow motor 50 is driven to rotate the rectangular prism mirror 66 and the like in the direction around the longitudinal axis. Further, when the three-dimensional coordinate measuring apparatus 10 is in the automatic measurement mode, the controller 70 drives each drive unit and the hollow motor 50 under the control of the control device 72 to displace the position and posture of the optical rotary probe 26. At the same time, the rectangular prism mirror 66 and the like are rotated around the longitudinal axis.

Further, the controller 70 is connected to the aforementioned detection units (the XYZ axis detection unit, the probe rotation angle detection unit, and the rotor rotation angle detection unit) (not shown), and signals and the like output from these units are controlled by the controller. 72.

FIG. 3 is an explanatory diagram for explaining the shape measurement of the measurement surface of the workpiece W using the optical rotating probe 26. FIG. As shown in FIG. 3 and FIGS. 1 and 2 already described, the wavelength swept light source 28 emits the measurement light LA to the fiber circulator 32 via the optical fiber cable 30 . The measurement light LA is a wavelength swept light whose wavelength sinusoidally changes in a given wavelength band at every given wavelength sweep period (fixed wavelength sweep frequency).

Fiber circulator 32 is connected to swept wavelength light source 28 via fiber optic cable 30 , to photodetector 36 via fiber optic cable 34 , and to fiber optic cable 44 of optical rotating probe 26 .

The fiber circulator 32 is, for example, a non-reciprocating unidirectional device and has three ports, and outputs the measurement light LA input from the wavelength swept light source 28 via the optical fiber cable 30 to the optical fiber cable 44. . Thereby, the measurement light LA from the wavelength swept light source 28 is input to the optical rotating probe 26 . As a result, the reflected light LB reflected by the measurement surface of the workpiece W and the reference light LC reflected by the input/output end 44 a are input to the fiber circulator 32 via the optical fiber cable 44 .

The fiber circulator 32 also outputs the interference signal SG of the reflected light LB and the reference light LC input from the optical rotating probe 26 to the photodetector 36 via the optical fiber cable 34 .

The photodetector 36 corresponds to the interference signal detection section of the present invention, and may be, for example, a silicon photodiode, an InGaAs (indium gallium arsenide) photodiode, a phototube, a photomultiplier tube, or the like. Under the control of the controller 72 , the photodetector 36 converts and amplifies the interference signal SG input from the fiber circulator 32 via the optical fiber cable 34 into an electrical signal and outputs the electrical signal to the controller 72 .

The control device 72 is composed of an arithmetic device such as a personal computer, and has an arithmetic circuit composed of various processors, memories, and the like. Various processors include CPU (Central Processing Unit), GPU (Graphics Processing Unit), ASIC (Application Specific Integrated Circuit), and programmable logic devices [for example, SPLD (Simple Programmable Logic Devices), CPLD (Complex Programmable Logic Device), and FPGAs (Field Programmable Gate Arrays)]. Various functions of the control device 72 may be realized by one processor, or may be realized by a plurality of processors of the same type or different types.

For example, in the automatic measurement mode, the control device 72 drives each driving unit (not shown) and the hollow motor 50 according to a predetermined measurement program to change the position and posture of the optical rotating probe 26 and the rectangular prism. and rotation of the mirror 66 or the like about its longitudinal axis. As a result, the measurement light LA of the optical rotary probe 26 rotates and scans the measurement surface of the workpiece W, and the photodetector 36 detects the interference signal SG for each of a plurality of measurement points on the measurement surface. As a result, the detection result of the interference signal SG for each measurement point is input from the photodetector 36 to the controller 72 . Note that, in the manual measurement mode, the control device 72 causes the measurement light LA to rotate and scan according to an operation input to an operation unit (not shown).

Further, in both the automatic measurement mode and the manual measurement mode, the control device 72 controls the measurement surface of the workpiece W from the rectangular prism mirror 66 based on the detection result of the interference signal SG for each measurement point detected by the photodetector 36. A distance L2 to the measurement point is calculated for each measurement point.

Specifically, based on the detection result of the interference signal SG for each measurement point, the control device 72 determines the total distance between the distance L1 from the incident/exit end 44a to the rectangular prism mirror 66 and the distance L2 for each measurement point described above. (L1+L2) is calculated for each measurement point. Note that the method for calculating the total distance value is a known technology (for example, JP-A-2016-024086 and JP-A-2018-084434), so a specific description is omitted here.

Next, the control device 72 calculates the distance L2 for each measurement point based on the calculation result of the distance total value for each measurement point and the known distance L1. Then, the control device 72 calculates the position and attitude of the optical rotating probe 26 for each measurement point, the rotation angle around the longitudinal axis of the rectangular prism mirror 66 for each measurement point, and the distance L2 for each measurement point. , to calculate the three-dimensional coordinates of each measurement point. Thereby, the control device 72 can calculate the shape of the measurement surface of the work W scanned by the measurement light LA.

[Effect of this embodiment]
As described above, the optical rotating probe 26 of the present embodiment rotates the rotating optical system 42 (rectangular prism mirror 66, etc.) with respect to the fixed optical system 40 without rotating the optical fiber cable 44, thereby measuring the workpiece W. Rotational scanning of the light LA becomes possible. This enables rotational scanning of the measurement light LA without using an optical rotary connector or twisting an optical fiber cable as described in Patent Documents 1 and 2 above. As a result, it is possible to prevent the deterioration of the light reception sensitivity of the reflected light LB caused by the abrasion of the optical rotary connector, and it is possible to cope with the polarization maintaining optical fiber cable, and the rotation of the optical rotating probe 26 (rotating optical system 42) is possible. Number limits are also circumvented.

[Optical Rotating Probe of Other Embodiment 1]
FIG. 4 is a cross-sectional view of the optical rotating probe 26 of another embodiment 1. FIG. In the above-described embodiment, the imaging lens 64 is provided inside the shaft 62, but as shown in FIG. Note that the optical rotation probe 26 of the other embodiment 1 has basically the same configuration as the optical rotation probe 26 of the above-described embodiment, except that the imaging lens 64 is arranged differently. For this reason, the same reference numerals are given to the same functions or configurations as those of the above-described embodiment, and the description thereof will be omitted.

The imaging lens 64 of another embodiment 1 is provided on an incident/exiting surface 66a, which is a surface facing the workpiece W in the rectangular prism mirror 66. As shown in FIG. The exit/incidence surface 66a is an exit surface for emitting the measurement light LA toward the measurement surface of the work W and an entrance surface for the reflected light LB reflected by the measurement surface of the work W to enter. Thus, by providing the imaging lens 64 on the exit/incident surface 66a, the measurement light LA is condensed onto the measurement surface of the workpiece W by the imaging lens 64 even if the focal length of the imaging lens 64 is short. can be made As a result, an imaging lens 64 with a short focal length can be used.

[Optical Rotating Probe of Another Embodiment 2]
FIG. 5 is a cross-sectional view of the optical rotating probe 26 of the second embodiment. In the optical rotating probe 26 of the above embodiment, the imaging lens 64 also rotates together with the shaft 62 and the like as the rotating optical system 42 rotates. ing.

The optical rotation probe 26 of the second embodiment has basically the same configuration as the optical rotation probe 26 of the above-described embodiment, except that it has a shaft 74 for fixing the imaging lens 64 to the fixed optical system 40. is. For this reason, the same reference numerals are given to the same functions or configurations as those of the above-described embodiment, and the description thereof will be omitted.

The shaft 74 corresponds to the second shaft of the invention. The shaft 74 is a hollow cylinder extending in a direction parallel to the optical path P, and has a longitudinal axis 74a (corresponding to the second longitudinal axis of the present invention) parallel to the optical path P. Also, the outer diameter of the shaft 74 is formed smaller than the inner diameter of the shaft 62 . One end of this shaft 74 is fixed to the stationary optical system 40 (excluding the rotor 54 ), for example the stator 52 .

The stator 52 is formed with a shaft holding portion 52a having a fitting hole through which the optical path P passes and extending in a direction parallel to the optical path P (longitudinal axes 62a, 74a). One end of the shaft 74 is fitted and fixed to the fitting hole of the shaft holding portion 52a. This fixes the shaft 74 to the stationary optical system 40 (optical fiber cable 44). As a result, the shaft 74 is held by the shaft holding portion 52a so as not to be rotatable around the longitudinal axis 74a (the longitudinal axis 62a).

With one end of the shaft 74 fixed to the shaft holding portion 52a, the longitudinal axis 62a of the shaft 74 coincides with the center line of the optical path P and the longitudinal axis 62a, and the inner surface 74b (the second inner surface of the present invention) equivalent) surrounds the optical path P.

The other end opposite to the one end of the shaft 74 is inserted through the inside of the shaft 62 and is open inside the shaft 62 and near the rectangular prism mirror 66 . An imaging lens 64 is provided inside the other end of the shaft 74 . If the inner diameter of the shaft 62 is the same in the above-described embodiment and the second embodiment, a lens having a smaller diameter than the imaging lens 64 in the above-described embodiment is selected as the imaging lens 64 in the second embodiment. be done.

Since the imaging lens 64 is fixed with respect to the fixed optical system 40 by providing the imaging lens 64 inside the shaft 74 in this way, the imaging lens 64 rotates according to the rotation of the rotating optical system 42 . is prevented. This prevents the optical axis of the imaging lens 64 from moving (vibrating) in the direction perpendicular to the optical path P due to the rotation of the rotating optical system 42 . As a result, the stability of the optical axis of the imaging lens 64 can be improved.

Although one end portion of the shaft 74 is fixed to the stator 52 in the second embodiment, it may be fixed to another portion of the fixed optical system 40 (excluding the rotor 54), for example, the head mounting portion 46. FIG.

[others]
In each of the above embodiments, the rotating optical system 42 is rotated by the hollow motor 50, but various rotating mechanisms having a hollow portion, such as a hollow rotary actuator having a hollow portion, may be used as the shaft rotating mechanism of the present invention. good too.

Alternatively, the rotating optical system 42 (shaft 62) may be rotated by a shaft rotating mechanism that does not have a hollow portion as long as the optical path P is not obstructed. An example of the shaft rotation mechanism in this case includes a driving source such as a motor disposed outside the optical path P, a gear formed on the outer peripheral surface of the shaft 62 (or the shaft holding plate 60), and the driving force of the driving source. and a drive transmission mechanism that transmits to the gear to rotate the gear.

In each of the above-described embodiments, the right-angle prism mirror 66 refracts the measurement light LA and the reflected light LB by 90°, but the refraction angles of the measurement light LA and the reflected light LB may be other than 90°. In each of the above-described embodiments, the rectangular prism mirror 66 is used as an example of the reflector of the present invention, but various reflectors such as mirrors may be used.

In each of the above embodiments, the wavelength swept light source 28 is used as the light source of the interferometer, and the end surface reflected light at the incident/exit end 44a is used as the reference light LC, but the total value (L1+L2) of the distances L1 and L2 can be calculated. If so, the type of light source and the type of interference optical system inside and outside the optical rotating probe 26 are not particularly limited. Also, in this case, part of the measurement light LA reflected by a reflecting surface other than the work W, such as a mirror and a prism, may be used as the reference light LC.

In each of the above-described embodiments, various optical systems such as the collimator lens 48 and the imaging lens 64 are arranged in the optical rotation probe 26. Regarding the types of optical systems arranged in the optical rotation probe 26 and whether or not they are arranged, may be changed as appropriate.

In each of the above embodiments, the rotating optical system 42 (the shaft 62, the rectangular prism mirror 66, etc.) is rotated with respect to the fixed optical system 40 having the optical fiber cable 44, thereby rotating and scanning the measurement light LA. Although examples have been described using FIGS. 1 to 5, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.

In each of the above embodiments, the three-dimensional coordinate measuring device 10 is taken as an example of the shape measuring device of the present invention. The present invention can be applied to a shape measuring device.

10 ... Three-dimensional coordinate measuring device,
26... optical rotating probe,
28 ... wavelength swept light source,
36 ... photodetector,
40... fixed optical system,
42 ... rotating optical system,
44 optical fiber cable,
44a... input/output end,
48 ... collimator lens,
50... Hollow motor,
52... Stator,
52a ... Shaft holding portion,
54 ... Rotor,
54a... Hollow part,
62 ... Shaft,
62a ... longitudinal axis,
62b... inner surface,
64 ... imaging lens,
66...Rectangular prism mirror,
66a... entrance/exit surface,
70 controller,
72 ... control device,
74 ... Shaft,
74a ... longitudinal axis,
74b... inner surface

Claims (5)

An optical rotating probe that emits measurement light emitted from a light source toward an object to be measured and receives reflected light of the measurement light that is reflected by the object to be measured,
a light guide path for guiding the measurement light and the reflected light, the light guide path having an exit and entrance end from which the measurement light is emitted and into which the reflected light is incident;
A first hollow first surface having a first longitudinal axis parallel to optical paths of both the measurement light emitted from the exit/incident end and the reflected light entering the exit/incidence end, and a first inner surface surrounding the optical paths. a shaft;
a shaft rotation mechanism that rotates the first shaft in a direction around the first longitudinal axis;
provided at the end of the first shaft opposite to the side facing the exit/incident end, and reflects the measurement light incident through the inside of the first shaft toward the object to be measured; a reflector that reflects the reflected light from the measurement object toward the incident/exit end;
an imaging lens provided inside the first shaft and condensing the measurement light onto the object to be measured;
a hollow second shaft inserted within the first shaft and having a second longitudinal axis parallel to the optical path and a second inner surface surrounding the optical path;
a shaft holding portion that holds the second shaft in a non-rotatable direction about the second longitudinal axis;
with
An optical rotary probe , wherein said imaging lens is provided inside said second shaft . 2. The optical rotary probe according to claim 1 , wherein a collimator is provided between said outgoing/incoming end and said first shaft. The shaft rotation mechanism is provided between the light guide path and the first shaft,
3. The optical rotary probe according to claim 1 , wherein the shaft rotating mechanism has a hollow portion through which the measurement light and the reflected light pass. 4. An optical rotary probe according to any one of claims 1 to 3 , wherein said reflector is a rectangular prism mirror. In a shape measuring device that measures the shape of an object to be measured,
a light source that emits measurement light;
an optical rotating probe according to any one of claims 1 to 4 ;
Interference signal detection for detecting an interference signal between the reflected light incident on the light guide path from the incident/exit end and reference light that is a part of the measurement light reflected by a reflecting surface different from the measurement object. Department and
A shape measuring device comprising:

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