JP7058869B2 - Optical imaging probe and optical measuring device - Google Patents

Description

In the present invention, the inner peripheral surface and the outer peripheral surface of a substantially cylindrical machine component or the like are simultaneously irradiated with observation light, and the return light (reflected light) from the inner outer peripheral surface of the object to be measured is taken in to capture the inner peripheral surface of the machine component. The present invention relates to a probe for optical imaging for observing the shape of an object and measuring coaxiality, and an optical measuring device using the probe for optical imaging.

For example, the inner / outer peripheral surfaces of the inner ring of a ball bearing are required to maintain high accuracy in coaxiality between both sides in addition to measuring the diameter and roundness of each surface. Further, in a slide bearing used for a rotating spindle of an optical disk device such as a DVD, the coaxiality of the inner / outer diameter and the diameter of the inner peripheral surface of the bearing are required with high accuracy. In addition, if these accuracyes are poor, the performance of electronic device products such as DVDs may not be obtained.

Conventionally, the measurement of the processing accuracy of these machine parts and the like has generally been performed by using a contact type measuring machine such as a roundness measuring machine. However, in recent years, an optical non-contact measuring machine has been demanded for the purpose of not damaging the object to be measured. As an example of diagnostic imaging technology (optical imaging technology) that acquires shape data of the inner surface of the object to be measured by a non-contact measurement method, for example, laser light, white light, etc. are irradiated to capture interference fringes from the return light, and the wavelength thereof. There is a method of obtaining an image by converting (frequency) or phase difference data into numerical data of shape by computer analysis.

However, in order to measure the coaxiality of these mechanical parts with high accuracy without contact, it is necessary to irradiate the inner peripheral surface and the outer peripheral surface at the same time and capture the return light from them at the same time. Optical probes and optical measuring instruments capable of measuring coaxiality have not been provided on the market.

For example, Patent Document 1 and Patent Document 2 show typical conventional structures of an observation device to which a technique of irradiating the surface of a mechanical part or the like with a light beam to observe or measure the inner surface is applied.

In Patent Document 1, the first irradiation unit emits a first light ray in a substantially right-angle direction, the second irradiation unit emits a second light ray at a tip in a substantially right-angle direction, and the angle of the mirror is variable. An optical probe is shown in which the direction of radiation of light rays is changed within a small range, data is collected three-dimensionally, and return light is obtained from two points on the inner peripheral surface.
However, although this optical probe can measure two points in a substantially right-angled direction, it cannot measure the coaxiality between the outer peripheral surface and the inner outer peripheral surface of the object to be measured.

In Patent Document 2, a condensing lens (20) radiates a light beam guided by an optical fiber (1, 2) at a slight angle forward, and a rotating prism mirror (3) laterally radiates the light beam. An optical imaging probe that collects three-dimensional data by performing a full-circle scan instead of one point on the side by rotating radiation is shown.
However, in this configuration, it was possible to observe only one place in a substantially right-angled direction, and it was not possible to measure the coaxiality of the inner / outer peripheral surfaces.

Japanese Patent No. 4864662 Japanese Patent No. 5961891

The present invention has been made in view of the above-mentioned conventional circumstances, and the subject thereof is to simultaneously irradiate the inner peripheral surface and the outer peripheral surface of the object to be measured such as a substantially cylindrical machine component with observation light. The purpose is to take in the return light (reflected light) to measure the dimensions and shape of the inner / outer peripheral surfaces and to measure the coaxiality between the inner / outer peripheral surfaces.

One means for solving the above problems is to configure a probe for optical imaging and an optical measuring device using the probe for optical imaging as follows.
The probe for photoimaging includes a plurality of optical path conversion means for changing the direction of light rays, and an inner translucent member and an outer translucent member which are hollow cylinders and have different diameter sizes. At least one of the plurality of optical path conversion means has a function of branching a light ray in a plurality of directions, and the inner translucent member and the outer translucent member are arranged substantially coaxially. Then, the object to be measured is inserted between the outer peripheral surface of the inner translucent member and the inner peripheral surface of the outer translucent member, and the object to be measured is translucent from the inner translucent member side to the outer translucent member. Light can be emitted from both directions from the member side. The optical measuring device obtains shape data of the measured object by a computer from the return light from the measured object obtained by this optical imaging probe.

Simultaneously irradiate the inner and outer peripheral surfaces of the cylindrical object to be measured with light rays, and take in the return light (reflected light) from the inner / outer surface of the object to be measured to observe the dimensions / shape of the object to be measured. Coaxiality data between inner / outer surfaces can be obtained.

Cross-sectional view of the first rotation angle state during forward scanning of the probe for optical imaging of the present invention. Cross-sectional view of the probe in the second rotation angle state Explanatory diagram of coaxiality measurement using the same probe Explanatory diagram of acquired waveform of the probe and reference measurement of translucent pipe Explanatory diagram of coaxiality by the same probe Axial slide state explanatory diagram of the probe Explanatory diagram of 3D measurement by the same probe Explanatory drawing of translucent pipe reference measurement by the same probe Second embodiment sectional view of the probe Explanatory drawing of an optical measuring apparatus using the probe for optical imaging of this invention.

The first feature of the optical imaging probe of the present embodiment is a plurality of optical path conversion means for changing the direction of light rays, and an inner translucent member and an outer translucent member which are hollow cylinders and have different diameter sizes. At least one of the plurality of the optical path conversion means has a function of branching a light beam in a plurality of directions, and the inner translucent member and the outer translucent member are arranged substantially coaxially. An object to be measured is inserted between the outer peripheral surface of the inner translucent member and the inner peripheral surface of the outer translucent member, and the object to be measured is viewed from the inner translucent member side and the above. It is possible to irradiate light from both directions from the outer translucent member side.
According to this configuration, the inner peripheral surface and the outer peripheral surface of the cylindrical object to be measured can be simultaneously irradiated with light rays, and the return light (reflected light) from the inner / outer peripheral surface of the object to be measured can be taken in. ..

As a second feature, as a more specific embodiment, it is configured as follows. A substantially tubular case is connected to the inner translucent member, and the outer translucent member is integrally fixed via the outer case, so that the inner translucent member or the inside of the case is integrally fixed. A fixed-side optical fiber fixed in a non-rotating state is arranged in, and a rotating-side optical fiber driven to rotate by a motor unit is arranged on the tip side of the fixed-side optical fiber. There are first to fourth optical path conversion means as the plurality of the optical path conversion means, and the first optical path conversion means and the second optical path conversion means are integrally arranged with the rotating side optical fiber, and the third optical path conversion is performed. The means and the fourth optical path conversion means are arranged integrally with the outer case. Then, the first optical path conversion means branches the light beam in a substantially perpendicular direction and a rotation axis direction, and the second optical path conversion means is located in front of the first optical path conversion and on substantially the same line, and the first (1) The light beam emitted from the optical path conversion means in the direction of the rotation axis is changed in angle in a substantially perpendicular direction, and is emitted from the inner peripheral side of the inner translucent member through the inner translucent member. Then, the third optical path conversion means converts the light rays emitted from the first optical path conversion means in a direction substantially perpendicular to the axis in parallel with the axis, and the fourth optical path conversion means is emitted from the third optical path conversion means. The light beam is converted into an angle in a substantially perpendicular direction, and is emitted from the outer peripheral side of the outer translucent member through the outer translucent member. Then, the return light from the inner peripheral surface of the hollow cylindrical object to be measured is guided from the second optical path conversion means to the fixed side optical fiber via the rotating side optical fiber and the first optical path conversion means, and the said. The return light from the outer peripheral surface of the object to be measured can be guided from the fourth optical path conversion means to the fixed optical fiber via the third optical path conversion means and the first optical path conversion means.
According to this configuration, the observation light is simultaneously irradiated with light rays on the inner peripheral surface and the outer peripheral surface of the object to be measured such as a cylindrical mechanical component by a plurality of optical path conversion means of the first to fourth objects to be measured. It is possible to capture the return light (reflected light) from the inner / outer peripheral surface of the.

A third feature is that the first optical path conversion having a function of branching a light ray in a plurality of directions is a polarization beam splitter composed of a plurality of rotating prisms.
With this configuration, the light beam can be stably branched in the perpendicular direction and the forward oblique direction, and since it is lightweight, the rotational load of the motor unit can be kept small.

The fourth feature is that the second optical path conversion means is a rotating mirror formed at a substantially right angle to the central axis and a substantially plane.
According to this configuration, the observation light can be radiated laterally from the probe to the object to be measured with a more compact structure.

A fifth feature is that the third and fourth optical path conversion means are substantially conical mirrors attached in a non-rotating manner.
According to this configuration, a light beam can be emitted to the object to be measured with a more compact structure.

As another feature, the shape data of the measured object is obtained by processing the return light from the measured object obtained by the optical imaging probe having at least one of the first to fifth features with a computer. It is in the construction of an optical measuring device that can be obtained.
According to this configuration, it is possible to observe the dimensions / shape of an object to be measured such as a cylindrical machine part and obtain coaxiality data between inner / outer peripheral surfaces.

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

1 and 2 are cross-sectional views showing the structure of the optical imaging probe of the first embodiment of the present invention.

As shown in FIG. 1, in the optical imaging probe, an inner case 6 made of a metal or the like and an inner translucent pipe 7 made of a material having a small thermal expansion such as quartz are connected as a translucent member. Similarly, the outer translucent pipe 10 made of quartz or the like is connected by the outer case 13 made of metal or the like and is integrally provided.

The non-rotating fixed-side optical fiber 1 is fixed to the inner case 6 by the fixture 14, the motor unit 8 is built-in and fixed in the inner case 6, and the motor unit 8 rotates the rotating-side optical fiber 2. The fixed-side optical fiber 1 and the rotating light-side optical fiber 2 face each other with a right-angled and smoothed end face, and face each other with a minute gap to form an optical rotating joint 3.

On the side of the rotating optical fiber 2 far from the motor unit 8, a first optical path conversion means 4 composed of, for example, a polarizing beam splitter, a plurality of prisms, a polarizing plate, and the like and having a function of branching light rays in a plurality of directions is attached. Has been Further, a second optical path conversion means is attached to the tip side thereof, and the light beam guided from the fixed side optical fiber 1 is rotationally emitted in a substantially right angle direction. Here, the "tip side" refers to the side closer to the tip of the probe. The bearing 9 is a bearing that supports the rotation of the rotating side optical fiber 2.

Inside the outer case 13, a third optical path conversion means 11 and a fourth optical path conversion means, which are formed of a mirror or the like having a reflecting surface having an inclination on the circumference, are attached. The light rays branched by the first optical path conversion means 4 and emitted in the perpendicular direction are optical path-converted substantially parallel to the rotation axis by the third optical path conversion means 11, and further, the optical path is converted again by the fourth optical path conversion means. The light beam guided from the fixed-side optical fiber 1 is transmitted from the outer peripheral surface of the outer translucent pipe 10 through the pipe 10 and radiated in the direction of the rotation axis.

FIG. 2 shows a state in which the motor unit 8 of the optical imaging probe is rotated and light rays are emitted to the opposite side of FIG. 1 by 180 degrees.

The operation of the probe for optical imaging of the present invention will be described below with reference to FIGS. 3 to 8.

FIG. 3 shows a state in which the probe for optical imaging of the present invention is inserted into the inner / outer peripheral surface of the object 16 having a substantially cylindrical shape. Light rays such as near-infrared light emitted from the optical unit main body 85 of the measuring device shown in FIG. 10 are guided to a probe for optical imaging via a fixed-side optical fiber 1. The light beam passes through the optical rotation joint 3 and is guided to the rotating side optical fiber 2 and the first optical path conversion means 4, and among the branched light rays, the portion guided forward is transmitted from the second optical path conversion means 5 inside. It passes through the sex pipe 7 and is radiated to the inner peripheral surface 16i of the object 16 to be measured. Here, "forward" refers to the direction toward the tip end side of the probe. The return light from the inner peripheral surface of the object 16 to be measured is optical from the fixed side optical fiber 1 via the inner translucent pipe 7, the second optical path conversion means 5, the first optical path conversion means 4, and the rotating side optical fiber 2. It is returned to the unit 85, analyzed by the computer 89, and the analysis result is displayed on the monitor 90. 84 is a polarizing device, 88 is an optical interference analysis unit, and 86 is a motor drive circuit.

Further, the light rays radiated from the first optical path conversion means 4 at a substantially right angle to the rotation axis are reflected by the third optical path conversion means 11 and the fourth optical path conversion means 12 and pass through the outer translucent pipe 10. It is radiated to the outer peripheral surface 16o of the object 16 to be measured. The return light from the outer peripheral surface 16o passes through the outer translucent pipe 10, the fourth and third optical path conversion means 12, 11, the first optical path conversion and branching means 4, the rotating side optical fiber 2, and the fixed side optical fiber 1, and is optically optical. It is returned to the unit body 85.

FIG. 4 is a diagram showing an example of analysis data of the return light by the computer 89, in which the vertical axis shows the radial distance and the horizontal axis shows the rotation angle of the rotational radiation. Six radius distance data are shown in FIG. 4, in which data (a) is the radius of the inner peripheral surface of the inner translucent pipe, (b) is the radius of the outer peripheral surface, and (c) is the measured object. It is the radius of the inner peripheral surface 16i of the object 16. Next, the data (d) is the radius of the outer peripheral surface of the outer translucent pipe 10, (e) is the radius of the inner peripheral surface, and (f) is the data showing the radius of the outer peripheral surface 16o of the object 16 to be measured.

In the actual measurement, calibration is performed before the start of measurement, but in this measuring machine, (a) the radius of the inner peripheral surface of the inner translucent pipe and (d) the radius of the outer peripheral surface of the outer translucent pipe 10. Performs comparative measurement with a ring gauge whose numerical value is guaranteed in advance to obtain the true radius of the translucent pipe (Rp1-in in the figure), stores the data in advance in the computer 89, and further hollows out. By measuring the outer diameter of the pin gauge of the shape, the true radius (Rp2-Outer in the figure) of the outer peripheral surface of the outer translucent pipe 10 is obtained, and the data is stored in advance in the computer 89.

Here, each of the data (a) to (f) in FIG. 4 is affected by the axial runout of about 1 to 3 micrometers in the radial direction of the motor unit 8 and the bearing 9 of the optical imaging probe, and the reproducibility is very high. It is scarce and cannot be used for high-precision measurement as it is.

Therefore, in FIG. 4, each measurement of the inner / outer peripheral surface of the object to be measured is the distance from the inner peripheral surface 16i to the inner peripheral surface of the inner translucent pipe 7 (R-in and Rp1-in in the figure). The true radius (Rp1-in in the figure) of the inner translucent pipe 7 obtained in advance by calibration is added to the radius distance to the distance.
Similarly, the correct radius measurement of the outer peripheral surface 16o is pre-calibrated to the distance from the outer peripheral surface 16o to the inner peripheral surface of the outer translucent pipe 10 (radial distance between R-outer and Rp2-outer in the figure). It is obtained by adding the true outer radius (Rp2-outer in the figure) of the outer translucent pipe 7 that has been obtained.

FIG. 5 is an example of the inner / outer diameter measurement data of the object 16 to be measured thus obtained.

As shown in FIG. 6, the probe for optical imaging is slid in the axial direction by the Z-axis elevating motor shown in FIG. 83 of the measuring machine of FIG. 10, so that the inner peripheral surface 16i and the outer peripheral surface 16o of FIG. 7 are three-dimensional. Shape and dimension data can be obtained. FIG. 8 is an example of the measured value.

According to the present invention, the diameter of the inner / outer peripheral surface of the object 16 to be measured is set based on the inner / outer translucent pipes 7 and 10, so that the influence of the runout of the motor unit 8 and the bearing 9 is completely excluded. However, it becomes possible to obtain probes and measuring instruments for optical imaging with good repeatability on the order of nanometers.

FIG. 9 is a cross-sectional view of a second embodiment of the optical imaging probe.
In the second embodiment, the fixed-side optical fiber 21 is relatively rotatably inserted into the hollow hole of the rotating shaft of the motor unit 28, and the condenser lens 22a is integrally configured at the tip thereof. .. The light beam emitted from the condenser lens 22a is emitted toward the first optical path conversion and the spectroscopic means 24, and the light ray is branched in a substantially perpendicular direction and a direction forward of the rotation axis.

Further, the rotating shaft of the motor unit 28 and the rotating side optical fiber 22 are connected by the rotating side fiber connector 23 and rotate integrally.
Subsequent configurations and operations are the same as those of the first embodiment shown in FIGS. 1 to 8.

As described above, according to the second embodiment of the present invention, it is possible to provide a probe for photoimaging with less attenuation in the optical path and capable of performing more accurate measurement.

The probe for optical imaging of the present invention simultaneously irradiates the inner peripheral surface and the outer peripheral surface of a substantially cylindrical object to be measured, such as mechanical parts, with observation light by a plurality of optical path conversion means, and the inside of the object to be measured / We can provide optical imaging probes that can capture the return light (reflected light) from the outer peripheral surface to observe the dimensions / shapes of mechanical parts and obtain coaxiality data between the inner / outer peripheral surfaces, and can be used for industrial and medical measuring devices. It is expected to be used for inspection equipment.

1, 21 Fixed side optical fiber 2, 22 Rotating side optical fiber 3 Optical rotating joint 4, 24 First optical path conversion means (prism, etc.)
5, 25 Second optical path conversion means (prism, etc.)
6,26 Inner case 7,27 Inner translucent pipe (cap)
8, 28 Motor unit 9, 29 Bearing 10, 30 Outer translucent pipe 11, 31 Third optical path conversion means 12, 32 Fourth optical path conversion means 13, 33 Outer case 14, 34 Fixed side optical fiber fixture 16 Object to be measured 22a Condensing lens 23 Rotating side fiber connector 80 Measuring table
81 Z-axis slider 82 Mounting part 83 Z-axis elevating motor 84 Polarizer 85 Optical unit body 86 Motor drive circuit 88 Optical interference analysis unit 89 Computer 90 Monitor 100 Rays

Claims (6)

Multiple optical path conversion means that change the direction of light rays,
It has an inner translucent member and an outer translucent member that are hollow and have different diameters.
At least one of the plurality of optical path conversion means has a function of branching a light ray in a plurality of directions.
The inner translucent member and the outer translucent member are arranged substantially coaxially.
An object to be measured is inserted between the outer peripheral surface of the inner translucent member and the inner peripheral surface of the outer translucent member.
A probe for photoimaging, characterized in that the object to be measured can be irradiated with light from both the inner translucent member side and the outer translucent member side. A substantially tubular case is connected to the inner translucent member, and the outer translucent member is integrally fixed via the outer case.
A fixed-side optical fiber fixed in a non-rotating state is arranged inside the inner translucent member or the case.
On the tip side of the fixed-side optical fiber, a rotating-side optical fiber that is rotationally driven by a motor unit is arranged.
There are first to fourth optical path conversion means as the plurality of optical path conversion means.
The first optical path conversion means and the second optical path conversion means are arranged integrally with the rotating side optical fiber.
The third optical path conversion means and the fourth optical path conversion means are arranged integrally with the outer case.
The first optical path conversion means branches a light ray in a substantially perpendicular direction and a rotation axis direction, and the light beam is branched.
The second optical path conversion means is located in front of the first optical path conversion means and on substantially the same line, and converts the angle of the light beam emitted from the first optical path conversion means in the rotation axis direction in a substantially perpendicular direction. Then, it is emitted from the inner peripheral side of the inner translucent member through the inner translucent member.
The third optical path conversion means converts the light rays emitted from the first optical path conversion means in a direction substantially perpendicular to the axis in parallel with the axis.
The fourth optical path conversion means converts the angle of the light beam emitted from the third optical path conversion means in a substantially right angle direction, and passes through the outer translucent member from the outer peripheral side of the outer translucent member. Release,
The return light from the inner peripheral surface of the hollow cylindrical object to be measured is guided from the second optical path conversion means to the fixed side optical fiber via the rotating side optical fiber and the first optical path conversion means, and is measured. The light according to claim 1, wherein the return light from the outer peripheral surface of the object is guided from the fourth optical path conversion means to the fixed side optical fiber via the third optical path conversion means and the first optical path conversion means. Probe for imaging. The probe for optical imaging according to claim 2, wherein the first optical path conversion means is a polarization beam splitter composed of a plurality of rotating prisms or polarizing plates. The second optical path conversion means is a rotating mirror that is substantially perpendicular to the central axis and is formed of a substantially plane, and at least a part of the right-angled projection surface including the central axis is notched so that light rays do not abut. 2. The probe for optical imaging according to claim 2. The probe for optical imaging according to claim 2, wherein the third optical path conversion means and the fourth optical path conversion means are substantially conical and are mirrors attached in a non-rotating manner. An optical measuring device, characterized in that shape data of a measured object is obtained by a computer from the return light from the measured object obtained by the optical imaging probe according to any one of claims 1 to 5.

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