JP6980267B2 - Probe for optical imaging - Google Patents

Description

The present invention relates to a three-dimensional scanning type optical imaging probe for three-dimensionally capturing and observing light reflected by a subject in an optical measuring device or a medical device.

Diagnostic imaging technology (optical imaging technology) is a technology that is widely used in the field of equipment, machinery, medical treatment, and the like. For example, in medical sites and manufacturing sites of precision machine parts, as a method of image diagnosis, X-rays capable of taking tomographic images and three-dimensional tomographic images in addition to general camera observation and ultrasonic diagnostic equipment are possible. Methods such as CT, nuclear magnetic resonance, and OCT images (optical interference tomography) that utilize the coherence of light are being researched and utilized. In recent years, the development of OCT diagnostic imaging technology that can obtain the finest captured images among these methods has attracted particular attention for this tomographic image and three-dimensional tomographic imaging.

OCT images often use near-infrared rays with a wavelength of about 1300 nm (nanometers) as a light source, but near-infrared rays are non-invasive to living organisms and have excellent spatial resolution because they have a shorter wavelength than ultrasonic waves. There is. Therefore, it is expected that the tomography method will be incorporated into the endoscope and used in the medical field for the detection, diagnosis and treatment of affected parts in blood vessels such as the stomach, small intestine and arterial flow of the human body. In industrial applications, it is expected to be applied to the measurement of accuracy in pipes and the measurement of coating film thickness. A typical structure of an OCT endoscope probe to which this OCT imaging technique is applied is, for example, as shown in Patent Document 1.

In the OCT endoscopic probe shown in Patent Document 1, an elongated tubular catheter is inserted inside the annular guide catheter shown in FIG. 1 in the document. The inside of the catheter has an optical fiber or a core that is rotatable and slidable and optically connected, and the optical fiber is rotated and moved in the length direction as shown in FIG. 3 in the document to move the body tissue. This is an OCT three-dimensional image system that irradiates an optical fiber and observes an analyzed image. However, in this configuration, there is a problem that frictional resistance is generated between the inner peripheral surface of the catheter and the inner core (106). In addition, the internal core (106) is rubbed, bent, and twisted, resulting in uneven rotation speed, delay in rotation transmission, fluctuation in torque loss, etc., which distorts the obtained analysis image and requires spatial resolution. I couldn't get it. Further, the internal core (106) rotates at high speed while being sealed by the high-speed sealing member (210) and is connected to the rotary joint [optical rotary joint] (214), but there is optical loss due to this optical rotary joint. , The size and cost of the equipment was a problem.

Japanese Patent No. 4520993

The present invention has been made in view of the above-mentioned conventional circumstances, and an object thereof is to rotate a light beam by reducing the occurrence of rotation transmission delay, torque loss, etc. in an endoscope type optical imaging probe. In addition to preventing rotation unevenness, shaft runout, rubbing, and rotation transmission delay of the radiating rotation mechanism, three-dimensional scanning of a certain length is performed by radiating not only in the rotation direction but also in the axial direction. Further, it is possible to realize a probe for optical imaging that can obtain a three-dimensional observation image with little optical attenuation while eliminating the need for an optical rotation joint.

One means for solving the above problems is configured as follows for an optical imaging probe that guides the light incident on the front end side to the rear side. An optical fiber arranged non-rotatably in a tube, a first optical fiber conversion means located on the tip side of the optical fiber and rotationally driven by a first motor to radiate light rays in a substantially radial direction, and an optical fiber and a first optical path conversion means. It is provided with a second optical path conversion means, which is located between the two and is rotationally driven by a second motor to rotate and radiate a light ray emitted from the tip of an optical fiber at a small angle with respect to the center of rotation. Then, the optical fiber, the first optical path conversion means, and the second optical path conversion means are arranged on substantially the same line so that the light rays can be emitted from the end face of the optical fiber toward the second optical path conversion means side.

According to the present invention, since the optical fiber is not rotated in a catheter such as an endoscope device, it does not rub, and rotation transmission delay and torque loss do not occur. In addition, it is not necessary to use a rotating optical joint, and optical loss is reduced. Furthermore, since the first optical path conversion means and the second optical path conversion means rotate independently, the radiation angle of the light beam can be intentionally changed in both the substantially radial direction and the central axis direction, so that the precision measurement for the inner surface of the deep hole can be performed. It is possible to obtain highly accurate observation image data with high three-dimensional spatial resolution in a machine or OCT endoscope.

Sectional drawing of probe for optical imaging which concerns on 1st Embodiment of this invention Configuration diagram of the inner surface measuring machine using the probe for photoacoustic imaging Explanatory drawing of rotational scanning direction of probe for photoacoustic imaging Explanatory drawing of rotational scanning direction of probe for photoacoustic imaging Explanatory drawing of rotational scanning direction of probe for photoacoustic imaging Explanatory drawing of rotational scanning direction of probe for photoacoustic imaging Explanatory drawing of rotational scanning direction of probe for photoacoustic imaging Explanatory drawing of 3D scanning range of probe for photoacoustic imaging Explanatory drawing of the pulse generation part of the first motor of the probe for photoacoustic imaging Explanatory drawing of the pulse generation part of the second motor of the probe for photoacoustic imaging Timing chart of motor pulse of probe for photoacoustic imaging Explanatory drawing of 3D image collected by the probe for photoacoustic imaging

The first feature of the optical imaging apparatus of the present invention is an optical fiber that is inserted into a non-rotatable tube and cannot rotate in an optical imaging probe that guides light incident on the tip side to the rear side, and the tip of the optical fiber. It is located on the side, is rotationally driven by the first motor, and is located between the optical fiber and the first optical path conversion means, and is rotationally driven by the second motor. A second optical path conversion means for rotating and radiating a light ray emitted from the tip of the optical fiber at a slight angle with respect to the center of rotation is arranged on substantially the same line, and the light ray is directed from the end face of the optical fiber toward the second optical path conversion means. It was made possible to release.
According to this configuration, the first optical path conversion means rotates to reflect the light rays sent to the optical fiber from the rear in a two-dimensional radial manner, and the second optical path conversion means rotates to emit the light rays. By changing the angle with respect to the center of rotation, three-dimensional observation becomes possible and a three-dimensional observation image can be obtained.

The second feature is that the rotation shafts of the first motor and the second motor are both hollow, and the second optical path conversion means is provided in the hole of the rotation axis of the first motor to which the first optical path conversion means is fixed. The fixed rotation shaft of the second motor was inserted so as to be relatively rotatably inserted, and the hole of the rotation shaft of the second motor was configured to pass a non-rotatable optical fiber or a light beam emitted from the optical fiber.
According to this configuration, since the optical fiber does not rotate, there is no twist or rotational friction, and the light beam is sent in the middle of the optical path without passing through the optical rotation joint, so that it is a compact, light attenuation, and high spatial resolution three-dimensional observation image. Can be obtained.

The third feature is a first pulse generating means that generates a pulse at least once per rotation according to the rotation angle of the first motor, and at least once per rotation according to the rotation angle of the second motor. It has a second pulse generating means for generating the above pulse, has a control means for adjusting the rotational speed of the first and second motors by the pulses from the first and second pulse generating means, and has the first motor. By rotating the relationship between the rotation speed N1 and the rotation speed N2 of the second motor at N2 = N1-X [rotation / sec], the rotation speed of N1 [rotation / sec] from the first optical path conversion means is approximately radial. The optical imaging probe according to claim 1 or 2, wherein the emission angle of the light beam is changed in the axial direction at a speed of X [reciprocating / second].
According to this configuration, while the light emission rotates at a high speed of N1 (for example, 30 rotations / second), the radiation angle is changed in the axial direction at a slow speed of X round trips per second (for example, 1 round trip / second), and the light beam is emitted. It is possible to radiate in a spiral shape, it is possible to efficiently collect three-dimensional data, and it is possible to obtain an endoscopic probe that obtains a three-dimensional observation image with high spatial resolution.

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

1 to 10 show embodiments of the optical imaging probe according to the present invention.
FIG. 1 is a cross-sectional view showing the structure of a three-dimensional scanning optical imaging probe according to the first embodiment of the present invention. The optical fiber 1 that guides a light beam from the rear end side to the tip side of the probe is inserted into a hole of a sufficiently long tube 6 and fixed in a non-rotating state by an optical fiber fixture 5.

The tip side of the optical fiber 1 is processed so that its end face is right-angled and smooth so that light rays can be emitted forward. Alternatively, a condenser lens 2 is attached to the tip side of the optical fiber 1 as needed, so that light rays can be further emitted without diffuse reflection.

The first motor 12 and the second motor 17 are arranged substantially coaxially with the optical fiber 1, and the first motor 12 has first bearings 9a and 9b, a first motor coil 10, a first rotor magnet 11, and a hollow hole. The first hollow rotating shaft 8 is composed of the first bearings 9a and 9b, the first motor coil 10 is fixed inside a thin tube 6 made of metal, for example, and the first rotor magnet 11 is the outer periphery of the first hollow rotating shaft 8. It is fixed to the surface. The optical fiber 1 is relatively rotatably inserted into the hole of the first hollow rotating shaft 8.

The second motor 17 includes second bearings 14a and 14b, a second motor coil 15, a second rotor magnet 16 and a second hollow rotary shaft 13 having a hollow hole, and the second bearings 14a and 14b and a second motor coil. 15 is fixed to the inside of the tube 6, and the second rotor magnet 16 is fixed to the outer peripheral surface of the second hollow rotating shaft 13. The second hollow rotary shaft 13 is relatively rotatably inserted into the hole of the first hollow rotary shaft 8.

A first optical path conversion means 3 including a first connecting portion and a mirror is fixed to the tip side of the optical fiber 1 of the first hollow rotating shaft 8 of the first motor 12, and the second hollow rotating shaft 13 of the second motor 17 is fixed. A second connecting portion 13a is attached to the tip end side of the optical fiber, and a second optical path converting means 4 made of a prism or the like is fixed between the first optical path converting means 3 and the optical fiber 1.

A translucent portion 7 made of glass, quartz, sapphire, or the like is attached to the vicinity of the tip of the tube 6 so as to allow light rays to pass through while protecting each internal component. Further, if necessary, a coating or the like is applied to reduce surface reflection and increase the transmittance of light rays.

A first collar 22 or a lubricant for enhancing slidability is inserted in the gap between the first hollow rotary shaft 8 and the second motor rotary shaft 13, and the optical fiber 1 and the second hollow rotary shaft 13 are inserted. A second collar 23 or a lubricant is inserted in the gap between them as needed to smooth the relative rotation.

The first pulse generating means 20a and 20b are attached to the first motor 12 as needed, and a pulse signal is generated by the rotation of the first motor 12. Second pulse generating means 21a and 21b are attached to the second motor 17 as needed, and are configured to generate a pulse signal by rotation of the second motor 17. However, if these first and first pulse generating means are not available, it can be replaced by detecting weak voltage pulses generated from the first and second motor coils 10 and 15.

The optical fiber 1 shown in FIG. 1 is a flexible glass fiber having a diameter of about 0.75 to 0.25 mm, and can be arranged inside the second hollow rotating shaft 13 in a contacted state. ing. However, the optical fiber 1 does not necessarily have to be arranged inside the second hollow rotating shaft, but is arranged on the main body 85 side of the second hollow rotating shaft, and only the light rays radiated from the end of the fiber 1 are the second hollow rotating shaft. The same effect can be obtained even if it penetrates the inside of 13 and is radiated to the second optical path conversion means.

The diameter of the hole of the second hollow rotating shaft 13 shown in FIG. 1 is 0.15 to 0.3 mm, and the material thereof is a metal or ceramic material. Then, it is made by drawing of molten metal with a die, electric pole processing, extrusion processing with a ceramic die before firing, etc., and the outer peripheral surface is finished by a polishing method or the like.

Further, a first wiring 18 usually composed of four thin lead wires is connected to the first motor 12, and a second wiring 19 is connected to the second motor 17.

FIG. 2 is a block diagram of an internal surface measuring machine using the probe for optical imaging of the present invention. The stand 81 is fixed to the base 80, and the slider 82 is moved up and down together with the optical imaging probe 36 of the present invention by the slider motor 83. The object 30 to be inspected is set on the base 80, the optical probe 36 goes in and out of the deep hole of the object 30 to be inspected, the optical fiber 1 is covered with a universal tube 31, and the connection portion 84 of the measuring machine main body 85 is connected. It is optically connected to the optical interference analysis unit 88 via the light interference analysis unit 88.

The light rays of near-infrared light or white light generated by the measuring machine main body 85 pass through the optical fiber 1 and are emitted from the translucent portion 7 of the optical probe 36. The light rays reflected on the inner peripheral surface of the object 30 pass through the optical probe 36, the optical fiber 1, and the connection portion 84 of the measuring instrument main body 85, enter the optical interference analysis unit 88, and are analyzed by the computer 89. The image is displayed on the monitor 90.

Further, the flexible tube 31 has a diameter of 5 mm or less and is made of a durable and flexible fluororesin tube or the like.

The first motor 12 in FIG. 1 is rotationally driven by being supplied with electric power from the first motor driver circuit 86 in FIG. 2, and the second motor 17 is rotationally driven by applying a voltage from the second motor driver circuit 87.

Next, the characteristic action and effect of the above-mentioned optical imaging probe of FIG. 1 will be described in detail with reference to FIGS. 3 to 12.

In FIG. 1, power is supplied from the first electric wire 18, and when the first motor 12 rotates at a constant speed of N rpm (range of about 1800 to 20,000 rpm), it is guided from the measuring machine main body 85 through the optical fiber 1. The light beam passes through the second optical path conversion means 4, is reflected by the first optical path conversion means 3 in a substantially perpendicular direction, and is emitted in the entire circumference of 360 degrees. Further, when electric power is supplied from the second electric wire 19 and the second motor 17 rotates at a constant speed slightly different from that of the first motor 12, for example, at (N−x) rpm, the first optical path conversion means rotates at a high speed at the same time. Since an angular phase difference is slowly generated between the first optical path conversion means 3 and the second optical path conversion means 4, the electric power is radiated in a three-dimensional direction in a screw shape.

FIG. 1 shows a momentary state in which the rotation angle (α) shown in FIGS. 9 and 10 of the first motor 12 is 0 ° and the rotation angle (β) of the first motor 17 is also 0 °. .. At this moment, the light beam is radiated downward in the direction of θ2 as shown by the arrow in the figure, the reflected light from the object to be measured returns from the same angle, passes through the optical fiber 1, and enters the optical interference analysis unit 88. do.

FIG. 3 shows a momentary state in which the rotation angle (α) of the first motor 12 is 180 ° and the rotation angle (β) of the first motor 17 is 180 °, which is the rotation of FIG. It is in an inverted state with the angle unchanged. At this moment, the light beam is emitted upward in the direction of θ2 as shown by the arrow in the figure.

In FIG. 4, a rotation phase difference is eventually generated between the two motors, and the rotation angle (α) of the first motor 12 is 0 ° and the rotation angle (β) of the first motor 17 is 90 °. It shows a certain momentary state. At this moment, the light beam is emitted in the downward direction, as shown by the arrow in the figure.

In FIG. 5, a rotation phase difference is eventually generated between the two motors, and the rotation angle (α) of the first motor 12 is 180 ° and the rotation angle (β) of the first motor 17 is 270 °. It shows a certain momentary state. At this moment, the light beam is emitted in the upward direction, as shown by the arrow in the figure.

In FIG. 6, a rotation phase difference is further generated between the two motors, and the rotation angle (α) of the first motor 12 is 0 ° and the rotation angle (β) of the first motor 17 is 180 °. It shows a certain momentary state. At this moment, the light beam is emitted at an angle of θ1 in the lower right direction as shown by the arrow in the figure.

In FIG. 7, a rotation phase difference is further generated between the two motors, and the rotation angle (α) of the first motor 12 is 180 ° and the rotation angle (β) of the first motor 17 is 180 °. It shows a certain momentary state. At this moment, the light beam is emitted at an angle of θ1 in the lower right direction as shown by the arrow in the figure.

The radiation range of the light beam at this time, that is, the scanning range of the optical interference endoscope has a diameter d2 (about 5 to 10 mm) from an outer diameter d1 (about 1.5 to 5 mm) of the translucent portion 7 as shown in FIG. It is designed so that light rays pass through to a distance and are in focus in the entire range between them, and it is scanned two-dimensionally in the entire circumferential direction of 360 degrees. When the first motor 12 and the second motor 17 rotate, the radiation direction of the light rays is gradually changed in the range of θ1 to θ2, so that the radiation range of the light rays is in the range of θ1 + 2θ and can be scanned three-dimensionally.

9 to 10, the first motor 12 is provided with the first pulse generating means 20a and 20b, and generates a pulse signal once per rotation. Further, the second motor 17 is provided with 21a and 21b to generate a pulse signal once per rotation.

FIG. 11 shows the generation pulse timing charts of the first motor 12 and the second motor 17 of the optical invention imaging probe, and the upper diagram in the figure shows the generation from the first pulse generation means 20 of the first motor 12. The pulse, the lower diagram in the figure shows the generated pulse of the second pulse generating means 21 of the second motor 17, and the horizontal axis shows the time axis.
The time zone indicated by Stand by in the figure is a state in which the first motor 12 and the second motor 17 are rotating at the same rotation speed and waiting for a scanning start signal.

Next, when the Start signal is output by the operation of the operator of the imaging probe, at the same time, the first motor 12 rotates at a speed represented by, for example, N pulses / second (for example, 30 rotations / second), and the subject is subjected to rotation. The OCT observation image data of the above is started to be accumulated in the computer 89.

At the same time, the second motor 17 rotates at a speed of, for example, (N-1) pulse / sec (for example, 29 rpm), so that the radiation angle is 0.5 sec from θ1 to θ2 as shown in FIG. It changes, and after 1 second, it returns to the angle of θ1 again and completes the emission of the light ray in the three-dimensional direction.

In this case, the computer captures a total of two (one set of two) three-dimensional data within the time it takes for the radiation angle to reciprocate between θ1 and θ2, and obtains a clear three-dimensional OCT diagnostic image without any omissions. When the data can be captured and stored, the first motor 12 and the second motor 17 are in the Stand by state again, and rotate while waiting for the next Start signal.

In the present embodiment, since the optical fiber 1 is not rotated in the long tube 6 inside the entire length from the rear to the tip of the tube 6, it does not rub, and it is possible to prevent the occurrence of rotation transmission delay and torque loss.

The most important required performance in the inner surface measuring machine using the optical imaging probe shown in FIG. 2 is to improve the measurement accuracy in the three-dimensional space, and the factor of the measurement accuracy is the first hollow rotating shaft of the first motor 12. There are runout accuracy of 8, shape accuracy and surface roughness of the first optical path conversion means 3 and the second optical path conversion means 4.

Of these, the one with the greatest influence is the rotational runout of the motor 12, so the motor 12 is built in at the tip, and the first optical path conversion means 3 is configured to rotate with high accuracy and even rotation speed. .. The endoscope probe of the present invention can stably achieve high three-dimensional shape accuracy (roundness, cylindricity, surface roughness) of, for example, 0.02 micron or less.

FIG. 12 is an example of a three-dimensional image collected by the probe for optical imaging of the present invention. Three-dimensional data of the inner peripheral surface with a diameter of 2 mm can be captured with high accuracy and high resolution.

According to the present invention, since the optical fiber is not rotated in the tube of the endoscope device or the like, the optical fiber is not rubbed, and the occurrence of rotation transmission delay and torque loss can be reduced. In addition, the synchronous rotation of the first and second optical path conversion means can radiate and scan light rays three-dimensionally, and the shape accuracy of small holes and deep holes can be measured with high accuracy of 0.02 micron level. It is possible.

The three-dimensional scanning type optical imaging probe of the present invention provides a highly accurate rotational scanning mechanism by providing an optical path conversion means that rotates evenly with a motor near the tip of the tube without rotating the optical fiber in the long tube. By having it, it is possible to improve the measurement accuracy of the precision measuring machine. Further, since the entire optical fiber can be fixed in a non-rotating state, it is not necessary to use a rotating optical joint, attenuation of light rays can be prevented, and measurement can be performed with high accuracy. As a result, it can be expected to be used for industrial internal surface measuring machines and industrial OCT devices, and can also be applied to medical endoscope devices.

1 Optical fiber 2 Condensing lens 3 1st optical path conversion means 4 2nd optical path conversion means 5 Optical fiber fixture 6 Tube 7 Translucent part 8 1st hollow rotating shaft 8a 1st connecting part 9a, 9b 1st bearing 10 1st motor coil 11 1st rotor magnet 12 1st motor 13 2nd hollow rotary shaft 13a 2nd connecting part 14a, 14b 2nd bearing 15 2nd motor coil 16 2nd motor magnet 17 2nd motor 18 1st wiring 19 2nd wiring 20a, 20b 1st pulse generating means 21a, 21b 2nd pulse generating means 22 1st color 23 2nd color 30 Object 31 Flexible tube 36 Probe 80 Base 81 Stand 82 Slider 83 Slider motor 84 Connection part 85 Measuring machine main body 86 1 Motor driver circuit 87 2nd motor driver circuit 88 Optical interference analysis unit 89 Computer 90 Monitor

Claims (2)

In a probe for photoimaging that guides light incident on the tip side to the rear side,
An optical fiber placed in a tube that cannot rotate, and
A first optical path conversion means, which is located on the tip side of the optical fiber, is rotationally driven by a first motor, and emits light rays in a substantially radial direction.
A second optical fiber located between the optical fiber and the first optical path conversion means, rotationally driven by a second motor, and rotationally radiating a light ray emitted from the tip of the optical fiber at a slight angle with respect to the center of rotation. The optical path conversion means are arranged on substantially the same line,
The first motor and the second motor are in the tube.
The first motor includes a first bearing, a first motor coil, a first rotor magnet, and a hollow first hollow rotating shaft.
The first bearing and the first motor coil are fixed to the inside of the tube.
The first rotor magnet is fixed to the outer peripheral surface of the first hollow rotating shaft.
The first optical path conversion means is fixed to the first hollow rotation shaft, and is fixed to the first hollow rotation shaft.
The optical fiber 1 is relatively rotatably inserted into the hole of the first hollow rotating shaft.
The second motor includes a second bearing, a second motor coil, a second rotor magnet, and a hollow second hollow rotating shaft.
The second bearing and the second motor coil are fixed to the inside of the tube.
The second rotor magnet is fixed to the outer peripheral surface of the second hollow rotating shaft.
The second optical path conversion means is fixed to the second hollow rotation shaft, and is fixed to the second hollow rotation shaft.
The second hollow rotary shaft is relatively rotatably inserted into the hole of the first hollow rotary shaft.
The optical fiber penetrates into the hole of the second hollow rotating shaft of the second motor.
A light ray is emitted from the end face of the optical fiber toward the second optical path conversion means, passes through the second optical path conversion means, is reflected by the first optical path conversion means in a substantially right angle direction, and is reflected in a substantially perpendicular direction, 360 degrees all around. A probe for optical imaging characterized by being able to emit light.
A first pulse generating means that generates a pulse at least once per rotation according to the rotation angle of the first motor, and a pulse generated at least once per rotation according to the rotation angle of the second motor. It has a second pulse generating means and a control means for adjusting the rotation speeds of the first motor and the second motor by the pulses from the first pulse generating means and the second pulse generating means.
By rotating the relationship between the rotation speed N1 of the first motor and the rotation speed N2 of the second motor at N2 = N1-X [rotation / sec], N1 [rotation / sec] from the first optical path conversion means. The probe for optical imaging according to claim 1, wherein the probe emits light in a substantially radial direction at a rotation speed of 1 and changes the emission angle of a light beam in the axial direction at a speed of X [reciprocating / second].

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