JP6232550B2 - Optical inner surface measuring device - Google Patents

Description

  The present invention allows the probe to enter the inner peripheral surface or deep hole inner diameter of the object to be inspected, emit light rays to the inner surface or deep hole bottom surface, capture the reflected light three-dimensionally, and improve the size and geometric accuracy. The present invention relates to an optical inner surface measuring apparatus for measurement.

  For example, the quality of machining finish and geometric accuracy of cylinders for automobile engines greatly affect the power performance and fuel consumption efficiency of automobiles, but these inspections are generally performed by roundness measuring machines, surface roughness meters, and linear scales. It was inspected using a contact-type measuring machine such as a length measuring machine. However, in recent years, optical non-contact measuring machines have been introduced for the purpose of not scratching the object to be measured.

  As a means of observing the presence or absence of scratches on the inner surface of the object to be measured without contact, image diagnostic technology (optical imaging technology) is a technology widely used in the field of equipment machinery, medical care, etc. At the manufacturing site, as a method of inspecting the deep part of the deep hole and diagnostic imaging, in addition to observing the camera with a general endoscope, it irradiates light and captures the reflected light with an optical sensor, and the state of uneven glossiness is detected with a computer. A method of judging and automatically inspecting is adopted.

  On the other hand, in the medical field, there are methods such as X-ray CT, nuclear magnetic resonance, and OCT image (optical coherence tomography) using an endoscope that can observe a tomographic image for observing an affected part inside a human body. Researched and utilized.

  Near-infrared light used as a light source in the medical field reflects when the material of the inner peripheral surface of the deep hole of the object to be measured is metallic, and when there is a resin film layer on the inner surface of the metal, near-infrared light halves the resin. Since it penetrates, it is possible to simultaneously measure the thickness accuracy of the coating resin and observe the pinholes on the resin surface simultaneously with the three-dimensional shape observation of the inner peripheral surface.

  A typical structure of an observation apparatus to which a technique for observing or measuring the inner peripheral surface by irradiating light to the inner peripheral surface of a mechanical device or machine part is as shown in Patent Documents 1 to 3, for example.

  In the optical endoscope probe shown in Patent Document 1, a reflection film (14) is provided at one end of a motor shaft (5) shown in FIG. 1 in the document, and light is rotated and emitted in the entire circumferential direction. However, in this configuration, the electric wire of the motor (1) or the wiring board (22), (23) blocks the light emitted from the rotation, so that it is not possible to radiate 360 degrees all around, and there is a portion where image data cannot be captured. .

In the inner diameter shape measuring sensor shown in Patent Document 2, a hollow motor (26) provided on the distal end side of the flexible tube (29) rotates the reflecting mirror (20) as shown in FIG. Emitting light rays. Also, the four strain gauges (5) shown in FIG. 4 measure the length (diameter) of the inner diameter of the object to be measured in the XY direction, correct the ambiguity of the optical measurement value, and The shape dimensions are displayed correctly on the screen.
In general, however, the inner diameter geometric accuracy of the object to be measured is required to be as high as 0.05 μm (micron). With this configuration, when the hollow motor (26) rotates at a high speed, the shaft runs out (Run Out). Alternatively, non-repeatable run-out occurs more than the accuracy required for the inner diameter shape measurement sensor, so distortion and noise are added to the cross-sectional shape data of the collected inner surface of the object to be measured. The measured value cannot be obtained.

Moreover, in the in-pipe shape inspection apparatus described in Patent Document 3, a light beam is scanned in a spiral shape in the pipe, and the inner diameter dimension of the pipe is contactless and the three-dimensional shape data as shown in FIG. Is captured and displayed.
However, this document does not show a mechanism for rotating and radiating a light beam, and when the rotating motor of the radiation beam rotates at a high speed, the inner peripheral surface of the object to be collected that is caused by vibration or non-reproducible vibration on the rotation shaft. There was noise on the cross-sectional shape data, or the data was distorted, and a true measurement value could not be obtained.

Japanese Patent No. 4461216 Japanese Utility Model Publication No. 4-55504 Japanese Patent Laid-Open No. 5-180627

  This invention is made | formed in view of the said conventional situation, The place made into the subject exists in the point shown next. That is, the measurement probe is inserted into the inner peripheral surface of the object to be measured, the inner diameter of the deep hole, or the inner periphery of the long and bent pipe, and the light beam is radiated to the inner surface or the bottom surface of the deep hole, and the reflected light beam is stereoscopically Collected and computer processed to observe 3D image data, and to measure dimensions and geometric accuracy. Furthermore, by removing the distortion and vibration noise of the image data caused by the shake or non-reproducible shake of the rotating shaft or rotating part radiating to the inner peripheral surface from the original data, the correct and accurate inner diameter and inner peripheral surface can be obtained. It is an object to provide an optical inner surface measuring apparatus that enables accuracy measurement.

One means for solving the above problems is an optical inner surface measuring apparatus that measures the dimensional accuracy of an object to be inspected using an interference optical method (optical interference method, spectral interference method, etc.). An optical fiber, at least one optical path conversion means disposed on the tip side of the optical fiber, a motor that rotationally drives one or both of the optical fiber and the optical path conversion means,
Displacement detecting means for measuring the shake amount of the rotating shaft portion of the motor is provided. With this configuration, the shape data of the inner peripheral surface of the test object obtained by calculating the reflected light introduced from the test object through the optical fiber is corrected by the displacement amount data of the shake detecting means.

  According to the present invention, the shake or non-reproduced shake of the rotating shaft of the motor that radiates and emits light removes the distortion and vibration of the image given to the collected original image data, and the correct and accurate tertiary surface of the inner peripheral surface is obtained. Original observation and measurement with high accuracy of inner diameter and inner peripheral surface are possible.

The figure of the optical inner surface measuring device concerning a 1st embodiment of the present invention Three-dimensional diagram of the inner diameter shape of the object to be measured of the optical inner surface measuring apparatus Surface roughness explanatory drawing of the optical inner surface measuring device Geometric accuracy explanatory diagram of the optical inner surface measuring device Probe part configuration diagram of the optical inner surface measuring device Cross-sectional view of the probe part of the optical inner surface measuring device Explanatory diagram of scanning range of the optical inner surface measuring device Explanatory drawing of surface roughness correction method of the optical inner surface measuring device Explanatory drawing of roundness correction method of the optical inner surface measuring device Angle pitch correction method explanatory diagram of the optical inner surface measuring device Hydrodynamic bearing cross section of the same optical inner surface measuring device Sectional view of the probe part of the optical inner surface measuring apparatus according to the second embodiment of the present invention 3D scanning method explanatory diagram of the optical inner surface measuring device Explanatory drawing of scanning angle of the optical inner surface measuring device Explanatory drawing of scanning angle of the optical inner surface measuring device 3D scanning range explanatory drawing of the optical inner surface measuring device Sectional view of a probe part of an optical inner surface measuring apparatus according to a third embodiment of the present invention 3D scanning range explanatory drawing of the optical inner surface measuring device Sectional drawing of the optical inner surface measuring apparatus which concerns on the 1st Embodiment of this invention Sectional view of the optical inner surface measuring device

The first feature of the optical inner surface measuring apparatus for observing and measuring an object to be inspected using the interference optical method of the present embodiment is that an optical fiber built in the tube, and at least a distal end side of the optical fiber are arranged. One optical path changing means, a motor that rotationally drives one or both of the optical fiber and the optical path changing means, and a displacement detecting means that measures the shake amount of the rotating shaft portion of the motor.
With this configuration, the measurement error associated with the shake of the rotating part can be corrected using the displacement amount data of the shake detection means, so that observation and measurement with high accuracy are possible.

As a second feature, at least one shake detection sensor is arranged such that the displacement detection means for measuring the shake amount of the rotation shaft portion of the motor is opposed to the outer peripheral surface of the rotation shaft portion of the motor.
With this configuration, the shake detection sensor collects the shake amount data of the rotating shaft and corrects the waveform data, thereby enabling accurate and accurate measurement of the inner diameter and inner peripheral surface.

The third feature is that the reflected light from the object to be inspected obtained through the optical fiber is based on the shape data of the inner peripheral surface of the object to be inspected and the displacement amount data of the displacement detecting means obtained by calculating with a computer. It is to be corrected.
According to this configuration, it is possible to remove image distortion and vibration caused by shake and vibration of the rotating shaft portion from the original waveform data, and to measure the inner diameter and inner peripheral surface more accurately and accurately.

The fourth feature is that the displacement detection means detects the difference between the reference shape data of the inner periphery of the tube and the measurement data of the tube inner peripheral surface obtained during the rotation of the rotating shaft as a shake amount.
With this configuration, distortion and vibration of the image applied to the shape data of the inner peripheral surface of the object to be inspected can be removed from the collected waveform data, and accurate measurement of the inner diameter and inner peripheral surface can be accurately performed.

As a fifth feature, the bearing that supports the rotating shaft of the motor is a dynamic pressure bearing with a dynamic pressure groove.
According to this configuration, the amount of shake of the rotating shaft of the motor, particularly non-reproducible shake, is reduced, and image distortion and vibration given to the shape data by the shake of the rotating shaft are reduced. Accuracy measurement is possible.

The sixth feature is that the rotating shaft portion of the motor has a hollow shape, the optical path changing means is disposed so as to be rotatable integrally with the rotating shaft portion, and the optical fiber is driven to rotate relative to the rotating shaft portion. It was made the structure inserted in the hollow hole of a shaft.
According to this configuration, the rotational drive source is arranged near the optical path built in the tube and in the vicinity of the optical path changing means. This reduces the distortion and vibration of the image given to the shape data by the shake of the rotating shaft, so that more accurate measurement of the inner diameter and inner peripheral surface is possible.

As a seventh feature, the motor includes a first motor and a second motor disposed on the rear side of the first motor, and the optical path conversion unit is a first optical path conversion unit operated by the first motor. And second optical path conversion means operated by the second motor. The optical fiber is on the rear side of the second motor, on the rotation side that rotates integrally with the fixed-side optical fiber that is non-rotatably arranged on the tube via the fixture, and the rotation shaft portion of the first motor or the second motor. It consists of optical fiber. And the rotating shaft part of a 1st motor and a 2nd motor each has a hollow shape. The rotation-side optical fiber has at least a part on the tip side inserted into the hollow hole of the rotation shaft part of the first motor and at least a part on the rear side fixed to the hollow hole of the rotation shaft part of the second motor. ing. The first optical path conversion means is disposed so as to be rotatable integrally with the rotation shaft portion of the first motor on the tip side of the second optical path conversion means, and the second optical path conversion means is a tip of the rotation side optical fiber. The structure provided in.
According to this configuration, since there is no electric wire of the first and second motors within the range in which the light beam is radiated and scanned three-dimensionally, the light beam cannot be shaded and the collected data is not missing. Measurement is possible.

As an eighth feature, the first optical path changing means in the configuration shown in the seventh feature is a rotatable mirror or prism.
According to this configuration, it is possible to perform highly accurate measurement with high reflection efficiency and reduced optical loss.

As a ninth feature, the second optical path changing means in the configuration shown in the seventh feature is a prism having a substantially flat surface inclined at the tip.
According to this structure, the light condensing property is high, and the optical loss can be reduced and highly accurate measurement can be performed.

As a tenth feature, the rotating shaft portion of the motor has a hollow shape, and an optical fiber is inserted into the hollow hole of the rotating shaft so as to be rotatable relative to the rotating shaft. The motor has a hollow sliding shaft portion extending rearward, and includes a linear actuator having the sliding shaft portion as an output shaft. And the optical fiber is being fixed to the hollow hole of a sliding shaft part. In this structure, the output shaft of the linear actuator pushes and pulls the optical fiber, and at the same time, the optical path changing means, the motor, and the optical fiber near the tip end are slid in the axial direction.
According to this configuration, the first and direct-acting motors are within the range in which light is emitted three-dimensionally by the operation of the motor and the linear motion motor, the shape data can be collected three-dimensionally, and the light is emitted and scanned. Therefore, it is possible to perform high-accuracy measurement with no shadow on the light beam and no missing data in the collected data.

  Next, preferred embodiments of the present invention will be described with reference to the drawings.

A first embodiment of an optical inner surface measuring apparatus according to the present invention will be described.
1 to 10 show an embodiment of an optical inner surface measuring apparatus according to the present invention.

  FIG. 1 shows an optical inner surface measuring apparatus according to a first embodiment of the present invention. A stand 81 is fixed to the base 80, and a slider 82 moves up and down together with the probe 28 by a slider motor 83. The DUT 61 is set on the base 80, and the probes 28 and 58 enter and leave the deep hole 61a of the DUT 61 shown in FIG. The light beam that has entered the probes 28 and 59 passes through the tube 6, further passes through the connection portion 84 of the measuring device main body 85, enters the optical interference analysis portion 88, is analyzed by the computer 89, and an image is displayed on the monitor 90. indicate.

This optical inner surface measuring apparatus has a plurality of, for example, eight types of functions, which are as follows.
[A] The function of displaying the three-dimensional shape of the inner surface of the deep hole 61a shown in FIG. 2 and the appearance inspection function of burrs, scratches, etc. [B] The surface film 61b such as resin is formed on the inner peripheral surface of the deep hole 61a. If it is applied, the film thickness is measured, and the function for inspecting pinholes and protrusions is poor [C] The surface roughness measurement function shown in FIG. 3 [D] The diameter measurement shown in FIG. Function [E] Roundness measurement function shown in (2) of FIG. 4 [F] The roundness measurement data of FIG. 4 (2) is continuously collected in the longitudinal direction and obtained in three dimensions. Cylindricity measurement function [G] Uneven height measurement function of inner peripheral surface shown in (3) of FIG. 4 [H] Angular pitch measurement function shown in (4) of FIG.

  FIG. 5 is a configuration diagram of the probe unit 28 of the optical inner surface measuring apparatus according to the first embodiment of the present invention. The tube 6 is connected to the distal end side and the rear side, the optical fiber 1 fixed to the optical fiber fixture 4 and a condensing lens 24 such as a ball lens are integrally formed on the distal end side, and the vicinity of the distal end of the fixed optical fiber 1. Has a motor 12 having a hollow rotary shaft 10 substantially coaxially.

  The fixed-side optical fiber 1 passes through the hollow rotary shaft 10 so as to be relatively rotatable, and a holder portion 10a extending to the distal end side of the hollow rotary shaft 10 has a first made of, for example, a mirror or a prism on the distal end side of the condenser lens 24. The optical path changing means 3 is attached and rotated.

  Light rays 26 and 27 sent from the rear side of the fixed-side optical fiber 1 and passing through the condenser lens 24 are reflected at an angle from the axial center line, pass through the translucent part 21, and enter the deep hole 61a of the object 61 to be measured. Irradiate. At this time, the light rays 26 and 27 are radiated to the entire 360-degree range as shown in FIG. In the figure, D1 is the outer diameter of the light projecting member 21, and the light rays 26 and 27 can radiate in the range of radius 2 mm to 10 mm (millimeter) shown in D2 in the figure and collect the reflected light.

  Further, since the slider motor 83 shown in FIG. 1 moves the probe 28 in the axial direction of the deep hole 61a and the light beam 26 slides in the axial direction while rotating, the light beam is emitted to the entire deep hole 61a shown in FIG. It is possible to collect 3D shape data.

  In the first embodiment shown in FIG. 5, the movement of the light beam 26 in the axial direction is not built in the probe 28, but is performed by the slide motor 83 provided outside shown in FIG. The straight movement accuracy of the movement of the lens is configured with high accuracy of 0.1 μm (micron) or less.

  The motor 12 includes a motor case 8, bearings 9 a and 9 b, a motor coil 7, and a rotor magnet 11 fixed to the hollow rotary shaft 10. Electric power is supplied to the motor 12 from the first motor driver circuit 86, and a three-dimensional image generated by analysis by the computer 89 is displayed on the monitor 90.

  5 and 6, two shake detection sensors 22 a and 22 b detect the shake amount and the shake angular direction of the outer peripheral surface of the rotating hollow rotary shaft 10. The shake detection sensor detects changes in capacitance and reflected light caused by the shake of the hollow rotary shaft 10, converts them into displacement amounts, and captures them as data.

Eight types of measuring methods and operations of the optical inner surface measuring apparatus of the present invention described above will be described in order below.
[A] Display of three-dimensional shape and appearance inspection method for scratches, etc. Reflected light from the deep hole 61a of the measured object 61 shown in FIG. 1 is taken into the optical interference analysis unit 88, calculated by the computer 89, and shown in FIG. Although an image similar to the shape is displayed, the slider motor 83 tackles the reflected light three-dimensionally while sliding the probe 28 in the axial direction, so that a three-dimensional image can be displayed on the monitor 90. In the present invention, it is possible to observe a clear three-dimensional image of the inner peripheral surface with high resolution, which cannot be obtained by a conventional CCD camera or ultrasonic sensor system.
Further, it is possible to detect a defective appearance product by separately storing in advance a reference data of an object to be measured free of burrs and scratches and comparing it with the surface state of the object to be measured 61 taken in.
[B] Next, when the inner peripheral surface of the deep hole 61a is coated with a surface film such as a resin, the measurement of the thickness of the surface layer 61b, the pinhole defect and the protrusion defect are near red. Since external light or laser light is semi-transmitted through the resin, a high-resolution three-dimensional image including a film can be obtained and the film thickness can be inspected.
[C] As shown in FIG. 8, the surface roughness measuring method is based on the original waveform data (dashed waveform on the upper side in the figure) of the surface of the inner peripheral surface of the object 61 to be measured within the sampling length range [for example, 100 μm (microns)]. At the same time, the shaft runout waveform data (the lower waveform in the figure) taken by the shake detection means (sensors 22a and 22b in FIG. 5) for the outer circumference runout of the hollow rotating shaft 10 is collected to obtain the original waveform data. The corrected data (the thin solid line waveform on the upper side in the figure) obtained by subtracting the shaft runout data from can be obtained. The width between the maximum value and the minimum value of the corrected data is the true maximum surface roughness value. Thus, by obtaining and correcting the outer peripheral runout data of the hollow rotating shaft 10, the surface roughness can be measured with high accuracy.
[D] The diameter measurement method is as follows. A waveform indicated by a broken line on the outer periphery of FIG. 9 is an original waveform indicating the shape of the inner peripheral surface of the object 61 to be measured, which is obtained by calculating the reflected light of the light beam emitted from the first optical path changing means 3 all around the computer 89. The shaft deflection displacement data obtained from the shake detection means (sensors 22a and 22b in FIG. 5) shown in the thick solid line waveform on the inner periphery in the figure is subtracted, and after correction shown in the fine solid line on the outer diameter side in the figure Data is obtained, and a necessary inner diameter dimension can be obtained from the corrected data.
[E] In the roundness measurement method, the thin solid line shown on the outer diameter side in the figure described above is the corrected data. The inscribed circle and the circumscribed circle are obtained by calculation, and the radius difference between these two circles is calculated. Can be defined as roundness.
[F] The method for measuring cylindricity is that the slide motor 83 slides the probe 28 together with the slider 82 with a high accuracy of 0.1 μm (micron) or less, and the roundness measurement data is continued in the longitudinal direction. The difference in radius between the inscribed cylinder and the circumscribed cylinder in the three-dimensional image of the cylinder obtained by collecting data can be defined as cylindricity.
[G] The measurement of the uneven height of the inner peripheral surface corresponds to, for example, the measurement of the depth of the dynamic pressure groove processed on the inner peripheral surface of the dynamic pressure bearing, and this measuring method is the surface roughness explained above. This is the same as the measurement method.
[H] In the angular pitch measurement method, when the first motor 12 rotates the first optical path changing means 3, rotation speed unevenness (referred to as jitter or wow flutter) of the first motor 12 occurs. 10, it is necessary to solve the problem that the measurement variation occurs when the true angle θ is within the range of the maximum θpmax to the minimum θpmin. As a countermeasure, the measurement is repeated a sufficient number of times, and the computer You can average to find the true value.

  In FIG. 5, the runout on the outer peripheral surface of the rotating hollow rotating shaft 10 is usually about 1 μm (micron), and the runout is a periodic runout once per rotation and the frequency is not fixed and the frequency is low. It can be separated into non-repeatable run out that occurs in a wide range from high to high frequency.

  There are several design methods and types of the first bearing 9a. For example, when the ball bearing type is adopted, the ball rolling vibration causes many non-reproducible vibrations. On the other hand, when the sintered oil-impregnated bearing system is adopted for the first bearing, there is a problem that many non-reproducible vibrations due to vibrations around the vibrations and vibrations from the contact surface occur.

  In the present embodiment, as shown in FIG. 11, a dynamic pressure bearing 9a is shown in which a dynamic pressure generating groove 9c is formed on the inner peripheral surface of the bearing. The dynamic pressure bearing 9a is a bearing that rotates simultaneously with the rotation by the dynamic pressure generating groove 9c applying a pumping force to a lubricating fluid such as oil, and the rotating shaft floats and rotates in a non-contact manner with high accuracy.

  For this reason, there is no rolling vibration or vibration that the conventional ball bearing has, and the vibration around and rubbing unlike the sintered oil-impregnated bearing, and therefore non-reproducible vibration is very small. As a result, when the original data shown in FIGS. 8 and 9 is corrected by subtracting the shaft shake data, the shaft shake data is corrected with a smooth waveform, so the measurement accuracy is further improved. Become.

  5 and 6, the displacement detection means for measuring the amount of vibration of the rotating shaft portion of the first motor has a plurality of vibration detecting sensors 22a and 22b opposed to the outer peripheral surface of the first hollow rotating shaft. There are other displacement detection means.

  For example, other displacement detection means for measuring the deflection amount of the rotating shaft portion of the first motor 12 are obtained during the rotation of the first motor and the reference shape data stored in advance on the inner periphery of the tube 6. A difference in measurement data on the inner peripheral surface of the tube can be detected as a shake amount. In this case, the thick solid line data on the inner periphery in FIG. 9 is the data of the shake amount obtained from the difference between the reference shape data on the inner peripheral surface of the tube and the measurement data obtained during the rotation of the first motor. Even with this configuration and detection method, the distortion and vibration of the image given to the shape data of the inner peripheral surface of the object to be inspected can be removed from the collected waveform data, and the accuracy of the inner diameter and inner peripheral surface can be accurately measured. . The tube 6 is made of glass or transparent resin. If necessary, the inner peripheral surface is provided with a translucent metal coating with a thickness of several nanometers, and the contour of the collected waveform from the inner peripheral surface is further improved. It can also be detected reliably.

19 and 20 are cross-sectional views of the optical inner surface measuring apparatus according to the first embodiment of the present invention. Light rays emitted from the first optical path changing means 3 (rotating mirror) are radiated from the inner peripheral surface 21a and the transparent member outer peripheral surface 21b of the transparent member 21 and the measured object 61, and the reflected light is The light is returned to the fixed optical fiber 1 through the first optical path changing means.
At this time, the first optical path shown on the inner circumference side of the 360 ° circumference data taken from either the transparent member inner circumference surface 21a or the transparent member outer circumference surface 21b is shown in FIG. The conversion means 3 corresponds to the shake amount, and the distortion or vibration of the image applied to the shape data of the inner peripheral surface of the inspection object can be removed or corrected from the collected waveform data by this measurement.
In FIGS. 19 and 20, the position of the probe 28 including the transparent member 21 is displaced inside the object to be measured. However, in any case, the first optical path changing means captures the shape data of the entire circumference while rotating. The inner diameter shape can be measured without any problem.

  The tube 6 has a diameter of about 2 mm (millimeter), and the fixed-side optical fiber 1 penetrating through the tube 6 is a bendable glass fiber having a diameter of about 0.1 mm to 0.4 mm (millimeter). using.

  The first optical path changing means 3 shown in FIG. 1 is composed of a mirror or a prism having a smooth reflecting surface, and its surface roughness and flatness are polished to an accuracy equal to or higher than that of a general optical component in order to increase the reflectance. Yes.

  A first hollow rotary shaft 10 shown in FIG. 1 is made of metal or ceramics, and is formed into a hollow shape by drawing with a molten metal die or extruding with a ceramic die before firing. Finished by etc.

  In FIG. 1, the hole of the first hollow rotating shaft 10 has a diameter of 0.2 mm to 0.5 mm (millimeter), and is sufficiently larger than the diameter of the optical fiber 1, so the fixed-side optical fiber 1 fixed by the fixture 4. Does not contact the first hollow rotating shaft 10, and even if lightly contacted, the wear powder is not generated. Further, there is no problem that the rotational friction torque varies.

12 to 16 show Embodiment 2 of the optical inner surface measuring apparatus according to the present invention.
FIG. 12 is a cross-sectional view of an optical inner surface measuring apparatus according to the second embodiment of the present invention. The fixed-side optical fiber 31 that guides the light beam from the rear end side to the front-end side of the probe 59 is inserted into a sufficiently long hole of the tube 36 and fixed by the optical fiber fixture 34.

  A rotation-side optical fiber 32 is rotatably provided at the distal end side of the fixed-side optical fiber 31. First optical path conversion means 33a and 33b made of a substantially planar mirror or the like are attached to the tip of the rotation side optical fiber 32 so as to be rotatable independently of the rotation side optical fiber 32 by the first motor 42. Is radiated in the entire circumferential direction.

  In addition, the light beam transmitted through the fixed-side optical fiber 1 is condensed at the tip of the rotation-side optical fiber 32 and is emitted toward the first optical path changing means 33a and 33b with a slight angle in the tip direction while rotating. Two optical path changing means 50 are attached.

  The rotation-side optical fiber 32 and the fixed-side optical fiber 31 are opposed to each other with a minute distance of about 5 μm (micron). A high transmittance can be maintained between the fixed-side optical fibers 31 and they are optically connected with almost no loss.

  In the first motor 42, the motor coil 37 and the first bearings 39b and 39a are fixed to the motor case 38, and the first hollow rotating shaft 40 to which the rotor magnet 41 is attached rotates. A voltage is applied from the electric wire 23 to the motor coil 37, and the first optical path changing means 33 is attached to the first hollow rotary shaft 40.

  Similarly to the first motor 42, the second motor 49 has second bearings 48 a and 48 b attached to the motor case 38 and obstructs the second rotating shaft 43 to be freely rotatable. In FIG. 12, the second rotating shaft 43 is lightly press-fitted into a hole 44 a formed in the approximate center of the vibrating element 44, but the spring 44 has a spring property between the vibrating element 44 and the second rotating shaft 43. A stable friction force is generated.

  An electrostrictive element or a piezoelectric element 45 is attached to the outer periphery of the vibration element 44, and an electrode 46 is formed on these elements. Each of these electrodes is wired by an electric wire 47 shown in FIG. 12, and a voltage is applied thereto. The vibrating element 44 is prevented from rotating with respect to the second bearings 48a and 48b, and the electric wire 47 may simply function to prevent rotation.

  In FIG. 12, a translucent part 51 capable of transmitting light is attached to the tube 36 in the vicinity of the outer periphery of the first optical path changing means 33 that emits the light. The inner peripheral surface or the outer peripheral surface of the light transmitting portion 51 is coated with a coating for reducing surface reflection and increasing light transmittance as necessary.

  The first motor 42 shown in FIG. 12 is supplied with electric power from the first motor driver circuit 86 shown in FIG. 1 and is driven to rotate. The second motor 49 is supplied with voltage from the second motor driver circuit 87 and is driven to rotate.

  The first optical path changing means 33 is constituted by a rotatable mirror or prism, and has high reflection efficiency and can reduce the optical loss and perform highly accurate measurement.

  The second optical path conversion means 50 is composed of a prism having a substantially flat surface inclined at the tip, and has high light-condensing properties, and can perform high-accuracy measurement with reduced optical loss.

  Next, the characteristic operational effects of the above-described three-dimensional scanning optical imaging probe shown in FIGS. 12 to 16 will be described in detail.

  In FIG. 1, a light beam such as a near infrared ray or a laser beam emitted from a light source in the measuring instrument main body 85 passes through a fixed side optical fiber 31 built in the tube 36.

  In FIG. 12, when electric power is supplied from the electric wire 23 and the first motor 42 and the second motor 49 are rotated at the same rotational speed in the range of about 1800 to 20,000 rpm, the guided light beam is transmitted to the rotating optical connector 52 and the rotating side optical fiber. 32, emitted from the second optical path changing means 50a, reflected by the substantially plane portion of the first optical path changing means 33a, and rotated and radiated in a constant angular direction (θ1 in FIG. 12). The radiation range at this time is an umbrella-shaped range having an angle θ1 as shown in FIG.

  Light rays such as near-infrared rays further pass through the translucent member 51, and light rays reflected from the object to be measured 61 are transmitted through the same optical path in the opposite direction to the translucent member 51 → first optical path conversion means 33a → second optical path conversion means 50a. ⇒Rotation side optical fiber 32 ⇒Rotation optical connector 52 ⇒The fixed side optical fiber 31 is passed to the optical interference analysis unit 88.

  Next, the rotation speed of the first motor 42 and the second motor 49 is, for example, the rotation speed of the first motor 42 is kept constant at 3600 rpm, while the rotation speed of the second motor 49 is rotated at a constant speed of 3570 rpm. Switch to a rotating state that gives a slight difference in motor speed. In this state, as shown in FIG. 13, when the rotation angle phase of the first optical path conversion means 33 and the second optical path conversion means is gradually changed to the position of 50b and a phase difference of 180 degrees is produced, The path of the light beam reflected by the rotating first optical path changing means 33b changes by a certain angle and changes to θ2 in the figure. The radiation range of light at this moment has changed to an inclined range as shown in FIG.

  This rotational phase angle is shifted by the difference from the rotational speed of the second motor 49, that is, 30 revolutions while the first motor 42 rotates 3600 times per minute, that is, a rotational phase difference of 360 degrees occurs every 2 seconds. .

  The shake detection sensor 53a detects the outer circumference shake of the first hollow rotary shaft, and corrects the collected original waveform data as in the first embodiment of FIG. Alternatively, other displacement detection means for measuring the deflection amount of the rotation shaft portion of the first motor 42 is obtained during the rotation of the first motor and the reference shape data stored in advance on the inner periphery of the tube 6. This is done by detecting the difference in the measurement data on the inner peripheral surface of the tube as the shake amount.

  Subsequently, the rotational phase difference between the first optical path changing means 33 and the second optical path changing means 50 continues to occur slowly every second in 2 seconds. With this operation, the radiation direction of the light beam continuously changes in the range of θ1 to θ2. As shown in FIG. 16, the radiation range of light is repeatedly irradiated three-dimensionally in the range of θ1 + θ2, and since there are no signal lines or electric wires 23, 47 in the scanning range, clear three-dimensional image data without missing is obtained. Can be obtained.

17 to 18 show a third embodiment of the optical inner surface measuring apparatus according to the present invention.
FIG. 17 is a cross-sectional view of the optical inner surface measuring apparatus according to the embodiment of the present invention. The fixed-side optical fiber 1 that transmits light between the tip side of the probe 59 (the direction side of the translucent member 21) and the rear side is built in the tube 36, and from the tip side of the fixed-side optical fiber 1 from, for example, a ball lens or the like. A condensing lens 24 is provided.

  A first optical path conversion unit 33 including a rotating mirror having an inclination angle is provided on the distal end side of the condenser lens 24, and is rotated by the first motor 12 when a voltage is applied from the electric wire 23.

In the first motor 12, a motor coil 7 is incorporated in a slidable motor case 8 supported by a slide guide 20 fixed to the inner peripheral surface of the tube 6, and is supported by bearings 9a and 9b. One hollow rotating shaft 10 is provided.
The rotor magnet 11 is fixed to the first hollow rotary shaft 10 and the first optical path changing means 33 is integrally attached thereto.

  A slide second shaft 57 is integrally provided on the rear side of the sliding motor case 8 on a substantially central axis. The slide second shaft 57 is a hollow shaft, and the fixed-side optical fiber 1 is inserted into this hole. It penetrates and is fixed by adhesion.

  The linear motion motor 62 is provided with slide bearings 58 a and 58 b that support the slide second shaft 57 in a motor case 68 provided in the tube 36, and a substantially polygonal column-shaped vibration element 54 is provided on the outer periphery of the slide second shaft 57. A piezoelectric element 55 having a pattern electrode 56 is affixed to at least the outer peripheral surface of the vibration element 54.

  When a voltage is applied from the electric wire 47 to the pattern electrode 56, the piezoelectric element 55 starts to vibrate, and a wave-like or triangular wave-like traveling wave is generated in the vibration element 54, whereby the slide second shaft 57 is fixed to the linear motion motor 62. The side optical fiber 1, the condensing lens 24, and the first optical path changing means 33 are slid in the axial direction within a range of, for example, 5 to 30 mm (millimeters) as indicated by Ls in the drawing.

  In FIG. 17, the length of the fixed-side optical fiber 1 built in the tube 36 is longer than the length of the tube 36 by at least Ls millimeters (mm), curved in the tube 36, and stored with a margin in length. doing. Therefore, when the linear motor 62 operates in FIG. 17 to move the slide second shaft 57 and the first motor 12 to the distal end side in the tube 36, the operation of pushing and pulling the fixed-side optical fiber 1 with a sufficiently small force, Can slide smoothly.

  Next, the characteristic operation and effects of the optical inner surface measuring apparatus shown in FIGS. 17 to 18 will be described in detail.

  In FIG. 17, when the electric wire 23 is energized, the motor coil 7 of the first motor 12 generates a rotating magnetic field, gives a rotational force to the rotor magnet 11, and the first hollow rotating shaft 11 causes the first optical path changing means 33 to be turned on. For example, it rotates at a constant speed in the range of 1800 rpm to 10,000 rpm.

  The first optical path conversion means 33 is indicated by 33a according to its rotational position, and the optical path conversion means at a position rotated by 180 degrees from that angle is indicated by 33b.

For example, a near-infrared ray or a laser beam emitted from the measuring device main body 85 in FIG. 1 is guided to the fixed-side optical fiber 1, emitted forward from the condenser lens 24, and substantially perpendicular to the first optical path changing means 33. The light radiated in the direction and reflected from the object 61 to be measured is returned to the measuring machine main body 85 through the fixed-side optical fiber 1 again, and the apparatus main body 85 can display an image.
Here, the probe 28 in FIG. 1 corresponds to the probe 59 in FIG. In addition, the tube 6 in FIG. 1 corresponds to the tube 36 in FIG.

  In FIG. 17, when the pattern electrode 56 is energized through the electric wire 47, the piezoelectric element 55 generates a traveling wave, and a sliding force is applied to the slide second shaft 57 toward the distal end side. The slide second shaft 57 starts to move the first motor 12, the first optical path changing means 33, the fixed-side optical fiber 1, and the condenser lens 24 integrally to the distal end side, and the light rays are substantially perpendicular or in the direction indicated by θ1 in the figure. 360 can be slid in the axial direction at the same time, so that the three-dimensional image data can be collected and stored in the measuring instrument body 85 in FIG. 1 by radiating in three dimensions as shown in FIG. Is done.

  17 and 18, when the slide second shaft 57 moves by a distance Ls in the drawing, the moving side sensor 64c approaches the fixed side sensor 64a and generates a signal indicating the completion of the sliding operation. The voltage applied to the electrode 56 is stopped. Alternatively, the application method changes, and the slide second shaft 57 starts to move in the opposite direction.

  The shake detection sensor 63a detects the outer circumference shake of the first hollow rotary shaft, and corrects the collected original waveform data as in the first embodiment of FIG. Alternatively, other displacement detection means for measuring the deflection amount of the rotating shaft portion of the first motor 12 is obtained during the rotation of the first motor and the reference shape data stored in advance on the inner periphery of the tube 6. The difference in the measurement data on the inner peripheral surface of the tube is detected as the shake amount.

  In addition, although the condensing lens 24 uses the ball lens, even if it uses a conical condensing lens, it is the same.

  One of the required performances of this type of three-dimensional scanning inner surface observation and inspection apparatus is to increase the spatial resolution. Factors for achieving the spatial resolution include uneven rotation speed of the first motor 12 and first hollow rotation. There are shake and non-reproducible shake accuracy of the shaft 10, accuracy of the first optical path conversion element 33, surface accuracy of the condenser lens 24, and the like.

  Of these, the influence of the motor 12 is greatly affected by this, but the present system in which the first motor 12 is built in the tip of the probe 59 stabilizes a high three-dimensional spatial resolution of, for example, 1 μm (microns) or less. Can be achieved. Further, the sliding motion in the axial direction of the linear motion actuator 22 can emit light in a certain range in the axial direction, and a high-resolution three-dimensional observation image can be obtained.

  As described above, the optical inner surface measuring apparatus of the present invention is provided with means for detecting the amount of vibration of the rotating shaft portion of the motor. The shape data of the inner peripheral surface of the inspection object obtained by calculating the reflected light obtained from the inspection object through the optical fiber by the computer is corrected with the displacement amount data of the displacement sensor. The measurement error caused by the vibration of the rotating shaft and the rotational vibration on the inner peripheral surface shape data of the collected object to be measured can be eliminated and highly accurate measurement can be performed.

The optical inner diameter measuring apparatus for observing and measuring a test object using the interference optical method of the present invention can be applied to an industrial diagnostic apparatus to perform high-accuracy measurement, for example, a tertiary at the bottom of a deep hole. Original observation can be performed. In addition, it is expected to be used for numerical diagnosis and treatment of dimensional changes of minute lesions in the medical field.

DESCRIPTION OF SYMBOLS 1, 31 Fixed side optical fiber 32 Rotation side optical fiber 3, 33a, 33b 1st optical path conversion means (mirror)
34 Optical fiber fixture 35 Shield plate 6, 36 Tube 7, 37 Motor coil 8, 38, 68 Motor case 9 a, 9 b, 39 a, 39 b First bearing 9 c Dynamic pressure generating groove 10, 40 First hollow rotating shaft 10 a Holder part 11 , 41 Rotor magnets 12, 42 First motor 20 Slide guide 21, 51 Translucent member 21a Transparent member inner peripheral surface 21b Transparent member outer peripheral surfaces 22a, 22b, 53a, 63a Shake detection sensors 23, 47 Electric wire 24 Condensing lens 25, 55 Scanning range 26 Light beam 28, 59 Probe 43 Second rotating shaft 44, 54 Vibrator 44a Hole 45, 55 Electrostrictive element 46, 56 Pattern electrode 48a, 48b, 58a, 58b Second bearing 49 Second motor 50, 50a, 50b Second optical path changing means (prism etc.)
52 Rotating optical connector (optical rotary connector)
57 Slide second shaft 61 DUT 61a Deep hole 61b Surface layer 62 Linear motors 64a, 64b, 64c Z-axis position sensors 70a, 70b Tube inner surface reflected light 71a, 71b Tube outer surface reflected light 72a, 72b, 72C Measured object reflected light 80 Base 81 Stand 82 Slider 83 Slider motor 84 Connection section 85 Measuring machine body 86 First motor driver circuit 87 Second motor driver circuit 88 Optical interference analysis section 89 Computer 90 Monitor

Claims (10)

In an optical inner surface measurement apparatus that observes and measures a test object using an interference optical method,
An optical fiber built into the tube,
At least one optical path changing means arranged on the tip side of the optical fiber;
A motor that rotationally drives one or both of the optical fiber and the optical path changing means;
An optical inner surface measuring apparatus comprising: a displacement detecting means for measuring a shake amount of a rotating shaft portion of the motor.   2. The optical inner surface measuring apparatus according to claim 1, wherein the displacement detecting means is arranged such that at least one detection sensor is arranged to face the outer peripheral surface of the rotating shaft portion. The shape data of the inner peripheral surface of the object the reflected light obtained by calculating by the computer from the object to be examined obtained through the optical fiber, and correcting the displacement amount data of the displacement detecting means The optical inner surface measuring apparatus according to claim 1 or 2. The displacement detection means detects the difference between the reference shape data of the inner periphery of the tube and the measurement data of the tube inner peripheral surface or outer peripheral surface obtained during rotation of the rotating shaft portion as the amount of deflection. The optical inner surface measuring apparatus according to any one of claims 1 to 3.   5. The optical inner surface measuring apparatus according to claim 1, wherein the bearing supporting the rotating shaft portion is a dynamic pressure bearing with a dynamic pressure groove. The rotating shaft portion of the motor has a hollow shape,
The optical path changing means is disposed so as to be rotatable integrally with the rotary shaft portion,
The optical inner surface measuring apparatus according to any one of claims 1 to 5, wherein the optical fiber is inserted into a hollow hole of the rotary shaft portion so as to be rotatable relative to the rotary shaft portion . The motor includes a first motor and a second motor disposed on the rear side of the first motor,
The optical path conversion means includes a first optical path conversion means operated by the first motor and a second optical path conversion means operated by the second motor,
The optical fiber is integrated with a fixed-side optical fiber disposed in a non-rotatable manner in the tube via a fixture on the rear side of the second motor, and the rotating shaft portion of the first motor or the second motor. It consists of a rotation-side optical fiber that rotates
Each of the rotating shafts of the first motor and the second motor has a hollow shape,
At least a part of the rotation side optical fiber is inserted into the hollow hole of the rotation shaft part of the first motor, and at least a part of the rear side is fixed to the hollow hole of the rotation shaft part of the second motor. Has been
The first optical path changing means is disposed so as to be rotatable integrally with a rotary shaft portion of the first motor on the tip side of the second optical path changing means,
The optical inner surface measuring apparatus according to any one of claims 1 to 5, wherein the second optical path changing means is provided at a tip of the rotation side optical fiber.   8. The optical inner surface measuring apparatus according to claim 7, wherein the first optical path changing means is a rotatable mirror or prism.   8. The optical inner surface measuring apparatus according to claim 7, wherein the second optical path changing means is a prism having a substantially flat surface inclined at the tip. The rotating shaft portion of the motor has a hollow shape,
The optical fiber in the hollow hole of the rotary shaft portion, is relatively rotatably inserted with respect to the rotary shaft portion,
The motor has a hollow sliding shaft portion extending rearward,
A linear actuator having the sliding shaft as an output shaft;
Fixing the optical fiber in the hollow hole of the sliding shaft,
6. The optical path changer, the motor, and the optical fiber in the vicinity of the tip side are slid in the axial direction simultaneously with the output shaft of the linear actuator pushing and pulling the optical fiber. 2. An optical inner surface measuring apparatus according to item 1.

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