JP2019191417A - Optical imaging probe - Google Patents

Abstract

To provide an optical imaging probe that can measure a coaxial degree and squareness of a bottom surface with respect to an inner peripheral surface in a hole depth part of a measured object.SOLUTION: The present optical imaging probe comprises: a transmissivity member 11 that is integral with a tube-like case 10; a non-rotation optical fiber 1 that is fixedly arranged on an inner side of the case 10; a plurality of optical path conversion means 3, 6 and 7 that converts a direction of a light beam; and two motors or more. At least one of the plurality of optical path conversion means 3, 6 and 7 has a function branching the light beam into a plurality of directions, in which a direction of the light beam radiated from the optical fiber 1 is converted by the optical path conversion means 3, 6 and 7, and is configured to enable discharging of the light beam heading for an almost right-angle direction with respect to an axial line at two or more portions on the axial line of a rotation axis, transmitting the transmissivity member 11, and is configured to enable radiating of the light beam heading for an oblique front with respect to the axial line of the rotation axis, transmitting the transmissivity member 11.SELECTED DRAWING: Figure 1

Description

  The present invention inserts an optical sensor into the bottom of a hole such as a machine part, irradiates light, and three-dimensionally captures return light (reflected light) from the object to be measured, and three-dimensional observation of the bottom. The present invention relates to an optical imaging probe used in an optical measurement device that measures the dimension of the bottom part three-dimensionally.

  For example, the quality of the finished machining dimensions and geometric accuracy of the cylinder bores and fuel injection nozzle inner surfaces of automobile engines greatly influences the power performance and fuel consumption efficiency of automobiles, but these inspections are generally roundness measuring machines, It was inspected using a contact-type measuring machine such as a surface roughness meter. 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 for acquiring the shape data of the inner surface of the measurement object in a non-contact manner, an image diagnostic technique (optical imaging technique), for example, three-dimensionally irradiates laser light, white light, etc., captures interference fringes from the return light, and There is a method of obtaining a three-dimensional shape image by converting wavelength (frequency) and phase difference data into numerical data of a three-dimensional shape by computer analysis.

  Conventionally, however, optical non-contact measuring instruments lack the mechanism of an optical imaging probe that three-dimensionally emits light by inserting an optical sensor into the back of a hole in a cylinder bore or fuel injection nozzle of an automobile engine. It was. In particular, if there is no optical probe that can measure the perpendicularity of the bottom of the hole, these measurements cannot be performed, and if the accuracy of the machine parts is poor, the cylinder bore of the automobile engine will affect the increase in pressure leakage and friction loss, The fuel injection nozzle has a problem that it affects the controllability of the injection amount and causes leakage.

  A typical structure of an observation apparatus to which a technique for observing or measuring the inner surface by irradiating light to the inner peripheral surface and the bottom portion of an object to be measured such as a machine part is shown in Patent Documents 1 to 3, for example. It is.

In the endoscope shown in Patent Document 1, half of the imaging range of the CCD camera is made transparent to observe the front, and the other half of the CCD imaging range has an angle so as to obtain a side image. By attaching a mirror, it is possible to simultaneously observe half of the front and side images simultaneously with one CCD.
However, since this endoscope has neither a rotation mechanism nor a slide mechanism, only one point on the front and one side can be observed, and the inner diameter, roundness, and hole of the inner peripheral surface can be observed. It was not possible to measure the agreement axis and perpendicularity of the bottom.

In addition, the optical imaging probe shown in Patent Document 2 radiates near-infrared rays guided to the optical fiber (1, 2) by a condensing lens (20) rotating at a slight angle forward. The rotating prism mirror (3) radiates to the side to scan the entire side, not a single point, and collects three-dimensional data by OCT.
However, with this configuration, the front observation cannot be performed, and the concentricity and perpendicularity of the hole bottom cannot be measured.

In the invention described in Patent Document 3, the first probe divides the light beam into two and irradiates the light beam in a direction substantially perpendicular to the linear direction, and the second irradiator emits the light beam in a substantially right angle direction at the tip. In addition, the angle of the mirror is changed to change the radiation direction of the light beam within a small range, and data is collected in three dimensions.
However, this optical probe can only observe two points in a substantially perpendicular direction, and cannot measure the coaxiality and squareness of the bottom of the hole.

JP 2001-299679 A Japanese Patent No. 5961891 Japanese Patent No. 4864662

The present invention has been made in view of the above-described conventional circumstances, and the problem is that, first, rotationally radiates at a plurality of locations on the inner peripheral surface with respect to the hole bottom of the object to be measured. Second, radiate one or more rotations at the bottom or obliquely, radiate observation light to three or more places in total, capture the return light from these, capture the three-dimensional shape of the inner peripheral surface and the bottom, and use a computer The purpose is to obtain an entire stereoscopic image. Another object of the present invention is to provide an imaging optical probe capable of measuring the inner diameter and roundness of the inner peripheral surface of the hole bottom and the coaxiality and perpendicularity of the hole bottom with reference to the inner peripheral surface.

  One means for solving the above-described problems is that, in an optical imaging probe used in an optical measurement apparatus, a translucent member integrated with a substantially tubular case, a non-rotating optical fiber fixedly arranged inside the case, A plurality of optical path changing means for changing the direction of the light beam, and two or more motors for rotating the optical path changing means. At least one of the plurality of optical path conversion means has a function of branching the light beam in a plurality of directions, and the direction of the light beam emitted from the optical fiber is converted by the optical path conversion means, and two locations on the axis of the rotation axis. As described above, the light beam traveling substantially perpendicular to the axis can be transmitted through the translucent member, and the light beam traveling obliquely forward with respect to the axis of the rotation axis can be transmitted through the translucent member and emitted. It is composed.

  According to the present invention, observation light is branched and radiated obliquely forward from a plurality of locations on the inner peripheral surface at the back of the hole of the object to be measured, and the three-dimensional shape is obtained by capturing the return light from a total of three or more locations. In addition, it is possible to provide an optical imaging probe that measures the coaxial and perpendicularity of the bottom surface with respect to the inner peripheral surface by computer analysis.

Sectional drawing of the 1st rotation angle state at the time of the front oblique scan of the probe for optical imaging of this invention Sectional view of the probe in the second rotation angle state Sectional view of the probe in the third rotation angle state Sectional view of the probe in the fourth rotation angle state Explanatory diagram of radiation area of the probe to the object to be measured Squareness measurement diagram using the probe Explanatory diagram of the acquired waveform and translucent cap reference measurement of the probe Explanatory drawing of inner surface measurement by the probe Illustration of the sliding state of the probe in the axial direction Extensive perpendicularity measurement explanatory diagram using the probe Beam diameter explanatory drawing of the probe second embodiment Roughness data acquisition explanatory diagram of the second embodiment Existence explanation of translucency reference pipe of the second embodiment Measurement apparatus using the optical imaging probe of the present invention

The first feature of the optical imaging probe according to the present embodiment is that a light transmitting member integral with a substantially tube-shaped case, a non-rotating optical fiber fixedly arranged inside the case, and changing the direction of the light beam A plurality of optical path changing means, and two or more motors for rotating the optical path changing means. At least one of the plurality of optical path conversion means has a function of branching a light beam in a plurality of directions, and the direction of the light beam emitted from the optical fiber is converted by the optical path conversion means. The light beam that travels substantially perpendicularly to the axis at two or more locations on the axis of the rotation axis can be transmitted through the translucent member, and the light beam that travels obliquely forward with respect to the axis of the rotation axis. It can be emitted through the translucent member.
With this configuration, the observation light diverges and radiates obliquely forward from the inner peripheral surface at the back of the hole of the object to be measured, and the return light is captured and shaped from a total of three or more locations on the inner peripheral surface and the front oblique direction. Data can be taken in, and the computer can obtain the entire three-dimensional image and the coaxial and perpendicularity of the bottom surface with respect to the inner peripheral surface.

The second feature of the present invention is configured as follows as a more specific embodiment. There are first to third optical path conversion means as the plurality of optical path conversion means, and a first motor that rotationally drives the first optical path conversion means, and a second motor that rotationally drives the second optical path conversion means and the third optical path conversion means. 2 motors. The first optical path conversion unit has a function of branching a light beam in a plurality of directions, and the second optical path conversion unit and the third optical path conversion unit are located in front of the first optical path conversion unit. is doing. Then, the first optical path changing means radiates the light beam by diverging it in a direction substantially perpendicular to the rotation axis direction and obliquely forward. The light beam branched in the direction of the rotation axis from the first optical path conversion means is guided to the second optical path conversion means or the third optical path conversion means. The light beam guided to the second optical path conversion means is converted in the optical path in a direction substantially perpendicular to the rotation axis direction. The light beam guided to the third optical path conversion means is converted into an optical path more diagonally forward.
A light beam emitted from the first optical path conversion unit in a direction substantially perpendicular to the rotation axis direction, a light beam emitted from the second optical path conversion unit, and a light beam emitted from the third optical path conversion unit, The optical imaging probe according to claim 1, wherein the probe passes through the translucent member and irradiates the object to be measured.
With this configuration, the first optical path conversion unit having a function of branching the light beam in a plurality of directions, the second optical path conversion unit and the third optical path conversion unit arranged in front of the first optical path conversion unit are used to transmit the observation light. It can radiate by being branched obliquely forward from the inner peripheral surface at the hole depth of the object to be measured. Then, by capturing the return light, the shape data is taken from a total of three or more of the inner peripheral surface and the front oblique direction, and the entire three-dimensional image and the coaxial of the bottom surface with respect to the inner peripheral surface are obtained by the computer of the optical measuring device. A squareness can be obtained.

According to a third aspect of the present invention, the first motor has a hollow rotary shaft, and the optical fiber is inserted into the hollow rotary shaft so as to be relatively rotatable. It is in having.
With this configuration, the size can be reduced, and the light emitted from the optical fiber can be stably irradiated onto the first optical path conversion unit.

The fourth feature of the present invention is that the first optical path changing means is a polarization beam splitter composed of a plurality of rotating prisms or polarizing plates.
With this configuration, the light beam can be stably branched in the right-angle direction and the front oblique direction, and since it is lightweight, the rotational load of the motor unit can be kept small.

A fifth feature of the present invention resides in that a large or small difference is given to the beam spot diameter of the light beam branched into two by the first optical path changing means.
With this configuration, it is possible to measure the shape such as the inner diameter and the roundness with the light beam having the larger inner beam spot diameter, and the surface roughness with the smaller light beam.

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

  1 to 4 show an embodiment of an optical imaging probe according to the present invention.

  FIG. 1 is a cross-sectional view of an optical imaging probe used in an optical inner surface measuring instrument according to an embodiment of the present invention. The non-rotating optical fiber 1 is located at a substantially central position of the substantially tube-shaped case 10, and the optical fiber 1 is fixed by an optical fiber fixture 12 that is integrally attached to the case 10. For example, a spherical condenser lens 2 is provided on the tip side of the optical fiber 1. A first motor unit is disposed between the optical fiber fixture 12 and the condenser lens 2, and a second motor unit is disposed between the optical fiber fixture 12 and the first motor unit. The rotation shaft 5b of the first motor is hollow, and the optical fiber 1 is inserted into the hollow hole so as to be relatively rotatable.

  A first optical path conversion 3 composed of a plurality of prisms, polarizing plates and the like in front of the condenser lens 2 and having a function of branching light rays in a plurality of directions is provided on the first hollow shaft 5b by the first rotating bracket 4. It is attached and driven to rotate. Here, “front” indicates a direction toward the distal end side of the probe. The first optical path changer 3 diverges and emits light rays in a direction substantially perpendicular to the axis with respect to the rotation center and obliquely forward. An optical component generally called a polarization beam splitter using a half mirror or a polarizing plate is used for branching the light beam.

  The second motor 9 is built in the case or attached at least integrally. In front of the first optical path conversion 3, a second optical path conversion means 6 and a third optical path conversion means 7 comprising mirrors are freely rotatable. These second and third optical path conversion means are the second rotation of the second motor unit 9. It is attached to the shaft 9b and rotates. The second rotating shaft 9b also has a hollow hole, and the first rotating shaft 5b of the first motor 5 is inserted into the hollow hole so as to be relatively rotatable.

  The operation of this embodiment will be described below. Light rays 100 such as near-infrared light emitted from the optical unit main body 85 of the measuring apparatus shown in FIG. 9 are guided to the condenser lens 2 via the optical fiber 1 and are emitted in front of the central axis. The light beam 100 is guided to the first optical path changer 3 and branched, and a part of the light beam is emitted in a direction substantially perpendicular to the central axis, and the remaining light beam is inclined at a slight angle with respect to the central axis at a substantially forward position. Yes, the light beam is emitted toward either the second optical path changing means 6 or the third optical path changing means 7.

  When the second and third optical path conversion means are assumed to be a plane perpendicular to the rotation center line, the second and third optical path conversion means are arranged at positions that divide the angle with respect to the rotation center within the plane, and obliquely forward from the first optical path conversion 3 When the second light path means 6 is irradiated to the light beam, the light beam is emitted in a direction substantially perpendicular to the central axis. On the other hand, when the third light path conversion means 7 is irradiated, the light beam is centered. Radiated obliquely to the axis. The light beam 100 is thus emitted at three or more locations.

In FIG. 1, the rotation angle of the first motor unit 5 is detected by a rotation sensor 5c made of, for example, an optical slit disk, and the rotation angle of the second motor unit 9 is detected by a rotation sensor 9c. The rotation angle of the first motor unit is 5c. The two motor units of the first motor unit 5 and the second motor unit 9 are synchronously rotated, and the first motor drive circuit 86 and the second motor drive circuit 87 in FIG. Since the rotation angle phase of the first hollow shaft 5b and the second hollow shaft 9b can be freely adjusted, the rotation phase difference between the first optical path conversion 3 and the second and third optical path conversion means can be controlled to rotate. Yes, the light beam can be selectively directed to the second or third optical path changing means.
In FIG. 1, the rotation angle (θ1) of the first motor unit 5 is 0 degrees and the rotation angle (θ2) of the second motor unit 9 is 0 degrees. A part of the light is emitted slightly obliquely downward, and the third optical path changing means emits the light path largely obliquely downward as indicated by α1 in FIG. 1, and is transmitted through the translucent cap 11 which is a translucent member. The object to be measured is irradiated.

  In FIG. 2, the rotation angle (θ1) of the first motor unit 5 is 45 degrees, and the rotation angle (θ2) of the second motor unit 9 is 0 degrees. In this case, a part of the light beam is emitted slightly obliquely downward from the first optical path conversion 3, and the optical path is emitted largely obliquely downward as indicated by α2 in the figure by the third optical path conversion means, and the translucent cap 11 is removed. The light is transmitted and irradiated on the object to be measured.

  In this way, a part of the light beam 100 is emitted via the optical fiber 1 ⇒ the condensing lens ⇒ the first optical path conversion 3 in a right angle direction ⇒ the translucent cap ⇒ emitted to the inner peripheral cylindrical surface of the object to be measured. . The remaining rays are emitted via the optical fiber 1 ⇒ condensing lens ⇒ first optical path conversion 3 with a slight angle to the center of rotation and emitted approximately forward ⇒ third optical path conversion means ⇒ translucent cap 11 ⇒ covered Radiated to the bottom of the measurement object.

  The return light of the light beam 100 such as near infrared light emitted to the inner peripheral surface and the bottom surface of the object to be measured passes through the translucent cap 11 and finally passes through the optical fiber 1 in the reverse order. It is returned to the main body 85 of the measuring apparatus shown in FIG.

  In FIG. 3, the rotation angle (θ1) of the first motor unit 5 is in the range of 135 degrees to 225 degrees, and the rotation angle (θ2) of the second motor unit 9 is at the position of 0 degrees. In this case, a part of the light beam is emitted slightly obliquely upward from the first optical path conversion 3, and the optical path is emitted in a substantially right angle direction in the drawing by the second optical path conversion means 6, and passes through the translucent cap 11 to be measured. The object is irradiated.

  In FIG. 4, the rotation angle (θ1) of the first motor unit 5 is 180 degrees, and the rotation angle (θ2) of the second motor unit 9 is 180 degrees. In this case, a part of the light beam is emitted slightly obliquely upward from the first optical path conversion 3, and the optical path is emitted largely obliquely downward as indicated by α 1 in the figure by the third optical path conversion means 7, and the translucent cap 11. And the object to be measured is irradiated.

  In this way, in FIGS. 5 and 6, the observation light 100 diverges in the direction of the inner peripheral surface 16 i and the bottom surface 16 b or obliquely forward at the back of the hole of the DUT 16, and the return light is captured. The three-dimensional shape of the peripheral surface and the front oblique direction is taken in, and the entire stereoscopic image and the coaxial and perpendicularity of the bottom surface with respect to the inner peripheral surface can be obtained by a computer.

FIG. 7 and FIG. 8 are explanatory diagrams of measurement based on the translucent cap 11 by the probe.
FIG. 7 is a diagram showing an example of analysis data of the return light by the computer 89. The vertical axis shows the distance, and the horizontal axis shows the rotation angle of the rotational radiation. FIG. 7 shows three radial distance data. Data (a) is the distance to the inner surface of the inner translucent cap 11, (b) is the distance to the outer surface, and (c) is the measured object. This is the distance to the inner surface 16i or 16b of the object 16.
In actual measurement, calibration is performed before the start of measurement. In this measuring machine, (a) the distance to the inner surface of the translucent cap 11 is the same as that of a ring gauge or block gauge whose value is guaranteed in advance. A comparative measurement is performed to determine the true distance (Rp1-in in the figure) of the translucent cap 11, and data is stored in the computer 89 in advance.
Here, each data of (a) to (c) in FIG. 7 is very poor in reproducibility due to the influence of the vibration of the two motor units 5 and 9 of the optical imaging probe of about 1 to 3 micrometers. As it is, it cannot be used for high-precision measurement. Therefore, in FIG. 7, each measurement of the inner / bottom surface of the DUT 16 is performed by measuring the distance from the inner surfaces 16 i and 16 b to the inner surface of the inner translucent cap 11 (in the figure, from R-in and Rp1-in). High accuracy measurement is achieved by adding the true distance (Rp1-in in the figure) of the translucent cap 7 previously obtained by calibration to the distance difference. FIG. 8 is an example of the inner diameter measurement data of the object 16 thus obtained.

9 and 10, the optical imaging probe of the present invention performs measurement over a wide range of the bottom as shown in FIG. 8 by moving it up and down with the shaft lifting motor 83 shown in FIG. 14 at the bottom of the measurement object 16. be able to.

  11 to 13 show data showing the second embodiment. The configuration of the second embodiment is the same as that of the first embodiment shown in FIGS.

  FIG. 11 shows the beam spot diameter of the light beam 100 irradiated on the surface of the object to be measured. One beam diameter 101a is small and is about 0.5 μm to 5 μm (micrometer). On the other hand, the diameter of 101b is large, and the light is condensed so as to have a size of 10 μm to 50 μm. In the second embodiment of the present invention, a difference in the beam spot diameters of the two light beams 100 branched by the first optical path changing and branching means 3 is provided, and the surface roughness of the DUT 16 is measured with the smaller light beam. On the other hand, the shape accuracy of the diameter and roundness of the DUT 16 is measured with the larger light beam. In this way, shape measurement such as inner diameter and roundness can be performed with one of the branched light beams, and surface roughness can be simultaneously measured with one probe using the other light beam.

  FIG. 12 shows an example of surface data taken from the surface of the measurement object 16 when the optical imaging probe is rotated by the two motor units 5 and 9 or is slid by the Z-axis lifting motor shown in FIG. It is. The data captured by the small beam 101a faithfully displays the surface roughness, while the data captured by the large beam 101b is not easily affected by the surface roughness and accurately captures large undulations on the surface. .

  FIG. 13 shows the captured waveform data (Cap Based) when the surface roughness data is captured with the small beam 101a as shown in FIGS. This is experimental data obtained by acquiring data (Without Cap) obtained by removing the cap 11 and measuring the distance to the object 16 to be measured. As can be seen from FIG. 13, when there is no translucent cap 11, undulations and noise are added to the waveforms captured by the rotational vibration and vibration play of the first motor unit 5 and the second motor unit 9, Noise was an obstacle to correct measurement. On the other hand, by providing a translucent cap 11 as in the configuration of the present invention and adopting a measurement method for obtaining the distance to the object 16 to be measured with reference to the surface of the cap, the correct surface roughness with no noise is eliminated. Measurement is possible.

  The translucent cap 11 is made of a material such as glass, quartz, or sapphire that has a low coefficient of linear expansion and good transparency, and reduces surface reflection as necessary to minimize total reflection of light rays. A coating or the like is provided to increase the holding transmittance.

According to the present invention, observation light diverges and radiates obliquely forward from a plurality of locations on the inner peripheral surface at the back of the hole of the object to be measured, and three-dimensional shapes are acquired by capturing return light from the three or more locations. By computer analysis, the coaxial and squareness of the bottom surface with respect to the inner peripheral surface can be measured, and the surface roughness can be measured simultaneously. Further, the accuracy of the inner / bottom surface of the DUT 16 is determined based on the translucent cap 11 so that the influence of the shake of the motor units 5 and 9 is completely excluded, and repeatability is reproducible in nanometer order. An optical imaging probe capable of performing good measurement can be provided.

The optical imaging probe of the present invention is an optical deep hole shape precision measuring instrument, which irradiates light on the inner surface and the inner part of a sliding bearing inner surface and a rear portion having an automotive engine injection nozzle having a deep hole and a small diameter hole. It is possible to obtain and observe both three-dimensional shape observation images of the bottom surface at the same time, and to perform precise measurement of geometric accuracy such as the perpendicularity of the inner peripheral surface and the bottom of the bottom. Industrial and medical measuring devices and inspection devices Expected to be used in

DESCRIPTION OF SYMBOLS 1 Optical fiber 2 Condensing lens 3 1st optical path conversion (prism etc.)
4 1st rotation bracket 5 1st motor unit 5a electric wire 5b 1st hollow shaft 5c rotation sensor 6 2nd optical path conversion means 7 3rd optical path conversion means 8 2nd rotation bracket 9 2nd motor unit 9a electric wire 9b 2nd hollow shaft 9c Rotation sensor 10 Case 11 Translucent cap (translucent member)
12 Optical Fiber Fixture 16 Measured Object 16i Hole Inner Perimeter 16o Hole Bottom 80 Measuring Stand
81 Z-axis slider 82 Mounting portion 83 Z-axis lift motor 84 Connection portion 85 Optical unit main body 86 First motor drive circuit 87 Second motor drive circuit 88 Optical interference analysis unit 89 Computer 90 Monitor 100 Light beam 101a, 101b Beam spot

Claims (5)

In an optical imaging probe used in an optical measurement device,
A translucent member integral with the substantially tubular case;
A non-rotating optical fiber fixedly arranged inside the case;
A plurality of optical path changing means for changing the direction of the light beam;
Two or more motors for rotationally driving the optical path changing means,
At least one of the plurality of optical path changing means has a function of branching a light beam in a plurality of directions,
The direction of the light emitted from the optical fiber is converted by the optical path changing means,
A light beam traveling substantially perpendicular to the axis at two or more locations on the axis of the rotation axis can be transmitted through the translucent member, and a beam traveling obliquely forward with respect to the axis of the rotation axis can be emitted. A probe for optical imaging, characterized in that the probe can be transmitted through a conductive member.
There are first to third optical path conversion means as the plurality of optical path conversion means,
A first motor for rotationally driving the first optical path changing means;
A second motor that rotationally drives the second optical path changing means and the third optical path changing means,
The first optical path changing means has a function of branching a light beam in a plurality of directions,
The second optical path conversion means and the third optical path conversion means are located in front of the first optical path conversion means,
The first optical path changing means radiates a light beam by branching it in a substantially perpendicular direction and obliquely forward with respect to the rotation axis direction,
The light beam branched in the direction of the rotation axis from the first optical path conversion means is guided to the second optical path conversion means or the third optical path conversion means,
The light beam guided to the second optical path changing means has its optical path changed in a direction substantially perpendicular to the rotation axis direction,
The light beam guided to the third optical path changing means is converted into an optical path more diagonally forward,
A light beam emitted from the first optical path conversion unit in a direction substantially perpendicular to the rotation axis direction, a light beam emitted from the second optical path conversion unit, and a light beam emitted from the third optical path conversion unit, The optical imaging probe according to claim 1, wherein the probe passes through the translucent member and irradiates the object to be measured.
The first motor has a hollow rotating shaft, the optical fiber is inserted into the hollow rotating shaft so as to be relatively rotatable, and the optical fiber has a condensing lens on the tip side. The optical imaging probe according to claim 2.
4. The optical imaging probe according to claim 2, wherein the first optical path conversion unit is a polarization beam splitter including a plurality of rotating prisms or polarizing plates. 5.
  5. The optical imaging probe according to claim 2, wherein a difference in magnitude is given to the beam spot diameter of the light beam branched into two by the first optical path changing means.

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