JP2016189890A - Optical imaging probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a loss of light amount in an optical imaging probe.
Light incident from an optical fiber F2 is transmitted through a first optical path conversion unit 15, optical path converted, and irradiated to a detected part X. The light reflected by the detected part X is opposite to the irradiation. Is passed through the first optical path conversion unit 15 and the optical fiber F2. At this time, an optical repeater 14 is provided between the optical fiber F2 and the first optical path changer 15 so as to transmit light between them and to have a uniform internal refractive index. The optical path changing unit 15 is formed of a material having an equivalent refractive index and is joined.
[Selection] Figure 1

Description

  The present invention relates to an optical imaging probe used in an optical imaging apparatus that acquires and images light reflected by a detection target part.

In recent years, OCT (Optical Coherence Tomography) technology using optical coherence has attracted attention as a diagnostic imaging technique. Near-infrared light having a wavelength of about 1300 nm is often used as a light source, but near-infrared light is non-invasive to living bodies and has a shorter wavelength than ultrasonic waves, so it has excellent spatial resolution and is approximately 10 to 20 μm. Since identification is possible, it is often used especially in the medical field.
The optical imaging probe used in OCT changes the optical path of light incident from an optical fiber, irradiates the detected part, and causes the light reflected by the detected part to pass through the optical fiber through a path opposite to the irradiation. (See Patent Document 1 and Non-Patent Document 1). The light returned from the optical imaging probe to the optical fiber is converted into an electric signal by the line sensor, and further analyzed and imaged by the image processing apparatus.

  By the way, according to the above-described conventional optical imaging probe, when light is incident on the GRIN lens from the space in the optical path where the light reflected by the detected portion returns, a part of the light is reflected on the GRIN lens (for example, non-lighted). There is a risk that the amount of light reflected by the front end face of GL1) of Patent Document 1 and taken into the line sensor will be reduced.

Japanese Patent No. 4461216

Jigang Wu, Micheal Conry, Chunhui Gu, Fei Wang, Zahid Yaqoob, and Changhuei Yang “Paired-angle-rotation scanning optical coherence tomography forward-imaging probe” OPTICS LETTERS (USA) May 1,2006 Vol.31, No.9 1265 ~ 1267

  The present invention has been made in view of the above-described conventional circumstances, and a problem to be solved by the present invention is to provide an optical imaging probe capable of reducing the loss of light amount.

  One means for solving the above problem is that in an optical imaging probe, light incident from an optical fiber is transmitted through an optical path conversion unit, converted into an optical path, irradiated to the detected unit, and the light reflected by the detected unit is reflected. Then, the light is passed through the optical path changing unit and the optical fiber through a path opposite to the irradiation. An optical repeater that transmits light between the optical fiber and the optical path changer and has a uniform internal refractive index is provided. The optical repeater and the optical path changer have an equivalent refractive index. It is formed by materials and bonded.

  Since the present invention is configured as described above, it is possible to reduce the loss of light amount.

It is sectional drawing which shows an example of the probe for optical imaging which concerns on this invention. It is a principal part expanded sectional view which shows operation | movement of the optical imaging apparatus. It is a principal part expanded section which shows operation | movement about the other example of the probe for optical imaging which concerns on this invention.

The first feature of the present embodiment is that light incident from an optical fiber is transmitted through an optical path conversion unit, converted into an optical path, irradiated to the detected unit, and the light reflected by the detected unit is opposite to the irradiation. In the optical imaging probe that is allowed to pass through the optical path changing unit and the optical fiber through the path, the light between them is transmitted between the optical fiber and the optical path changing unit, and the internal refractive index is uniform. An optical repeater is provided, and the optical repeater and the optical path converter are formed and joined with a material having an equivalent refractive index.
According to this configuration, when the light reflected by the detection unit passes through the optical path conversion unit in the reverse direction and enters the optical relay unit, the amount of light due to reflection at the boundary surface between the optical path conversion unit and the optical relay unit is reduced. Loss can be reduced.
The “optical repeater” may be a mode in which a translucent member separate from the optical fiber is connected to the front end of the optical fiber. As another example, a part of the core on the front end side of the optical fiber is optically relayed. It can also be used as a part.

  As a second feature, as a specific mode for reducing the loss of light quantity, the optical repeater is formed in a long shape along the optical axis of the optical fiber and is coaxially joined to the front end of the optical fiber.

  As a third feature, in order to reduce the loss of light quantity particularly in the optical path conversion unit, the optical path conversion unit reflects the light incident from the optical repeater side in a direction intersecting the incident direction. The reflection optical element and a second reflection optical element that reflects light incident from the first reflection optical element side in a direction crossing the incident direction are joined to each other.

  As a fourth feature, in order to reduce the loss of the light amount at the joint portion, a translucent adhesive having an equivalent refractive index to these two members is used for joining the optical relay portion and the optical path changing portion. It was.

  As a fifth feature, in order to facilitate the positioning of the joint portion, the two member members arranged in the optical path direction have a polygonal shape having the same area between the joint end surface of one member and the joint end surface of the other member. I made it.

  As a sixth feature, in order to ensure a wide irradiation area, the optical path conversion unit is a first optical path conversion unit, and is emitted by the first optical path conversion unit on the emission direction side of the first optical path conversion unit. A second optical path conversion unit that converts the optical path of the light to be transmitted, and the optical relay unit, the first optical path conversion unit, and the second optical path conversion unit are respectively centered on the optical axis of the optical relay unit. A first rotation drive source that supports the rotation and rotates the optical repeater and the first optical path conversion unit; and a second rotation drive source that rotates the second optical path conversion unit. The rotational speeds of the optical repeater and the first optical path converter were made different from the rotational speed of the second optical path converter by controlling the first rotational drive source and the second rotational drive source, respectively.

  Next, a preferred embodiment having the above features will be described in detail with reference to the drawings.

FIG. 1 shows an optical imaging probe 1 according to the present invention.
The optical imaging probe 1 rotates the first rotating element 10 rotatably supported, the second rotating element 20 supported to rotate on the front side of the first rotating element 10, and the first rotating element 10. A first rotation drive source 30 and a second rotation drive source 40 that rotates the second rotation element 20 are provided.
The optical imaging probe 1 converts the light incident from the optical fibers F1 and F2 by the first optical path conversion unit of the first rotation element 10 and the second optical path conversion unit of the second rotation element 20. Irradiate the detected part X and reflect the light reflected by the detected part X to the first and second optical path changing parts and the optical fibers F1 and F2 in the reverse path to the irradiation to the detected part X. Let it pass. The light returned to the optical fiber F1 is analyzed by an optical imaging apparatus such as OCT (not shown), and information such as the shape of the detected part X is imaged.

The optical fiber F1 is connected to an optical imaging apparatus (not shown) and is supported so as not to rotate.
The optical fiber F2 is coaxially disposed on the front side of the optical fiber F1, and is inserted into the center of the first rotation element 10, the first rotation drive source 30, and the second rotation drive source 40 described later.
A light correction member f1 is connected to the front end of the optical fiber F1, a light correction member f2 is connected to the rear end of the optical fiber F2, and a gap s is secured between the light correction members f1 and f2. The light correction members f1 and f2 are graded index optical fibers that expand and collimate light emitted toward the gap s.

  The first rotating element 10 includes a hollow support body 11, a spacer 12 fitted on the rear end side of the support body 11, and a tube body 13 fixed in the spacer 12 and having an optical fiber F2 inserted therein. And an optical repeater 14 linearly connected to the front end of the optical fiber F2, a first optical path converter 15 connected to the front end of the optical repeater 14, and a front end of the first optical path converter 15 The lens 16 is configured so as to be integrally rotatable.

  The support 11 is a columnar member having a hollow storage space S therein, and is made of a hard material such as metal or synthetic resin, for example. In the support 11, the first optical path conversion unit 15, the optical relay unit 14, and the spacer 12 into which the front end portion of the tube body 13 is inserted are inserted and fixed. Note that the gap in the storage space S is filled with synthetic resin as necessary.

The spacer 12 is a columnar member having a through hole in the front-rear direction at the center, and is formed of a hard material such as metal or synthetic resin, for example.
The spacer 12 is press-fitted and fixed to the inner peripheral surface on the rear end side of the support body 11 in a state in which a tube body 13 described later is press-fitted and fixed.

The tubular body 13 is a long cylindrical member made of a hard metal material, ceramic, or the like, and its front end side is press-fitted into the spacer 12, and the rear side portion thereof is a first rotational drive source 30 and a second one described later. It extends in a long shape so as to be inserted into the two rotational drive sources 40.
The optical fiber F2 and the light correction member f1 described above are inserted into the tube 13.
The front end portions of the optical fiber F2, the spacer 12, and the tube body 13 are flush with each other.

The optical repeater 14 is a translucent member having a polygonal cross-section with a uniform (substantially uniform) internal refractive index, and is coaxially joined to the front end of the optical fiber F2 and elongated forward. It is extended.
More specifically, the optical repeater 14 is formed in a long shape having a square cross section and extending in the optical axis direction of the optical fiber F2, and the front end thereof is connected to the optical axis of the optical repeater 14. It has the inclined surface 14a which faces to the direction (According to FIG. 2, diagonally downward forward) (refer FIG. 2). That is, the inclined surface 14 a is a surface that is inclined with respect to a plane orthogonal to the optical axis of the optical relay unit 14.
The material of the optical repeater 14 is a material having a refractive index equivalent (substantially equivalent) to that of a first optical path converter 15 described later, and is, for example, quartz glass or other glass material.
The rear end surface of the optical repeater 14 is formed into a flat surface perpendicular to the optical axis of the optical repeater 14. As shown in FIG. 2, this flat surface is joined to these front end surfaces so as to straddle the front end portions of the optical fiber F2, the tube body 13, and the spacer 12.
The first optical path conversion unit 15 is joined to the inclined surface 14a at the front end of the optical relay unit 14.

  The first optical path conversion unit 15 reflects light incident from the optical relay unit 14 side in a direction intersecting the incident direction, and is incident from the first reflective optical element side 15a. The second reflection optical element 15b that reflects the reflected light in a direction intersecting the incident direction is joined.

  The joining end face of the optical relay unit 14 and the joining end face of the first optical path changing unit 15 are formed in a polygonal shape (for example, a square shape) having the same area, and these outer edges are overlapped and joined.

The first reflective optical element 15a is a prism having an incident surface having the same area and shape (rectangular shape in the illustrated example) as the inclined surface 14a at the front end of the optical relay unit 14, and the incident surface is the front end of the optical relay unit 14 It adheres to the inclined surface 14a. The first reflective optical element 15a reflects light that enters the first reflective optical element 15a from the optical repeater 14 to the internal reflection surface, thereby intersecting the optical axis of the optical repeater 14 ( According to FIG.
The material of the first reflective optical element 15a is a material having a refractive index equivalent (substantially equivalent) to that of the optical repeater 14 as described above, and is, for example, quartz glass or another glass material.

The second reflective optical element 15b is a prism bonded to the emission side surface (the lower surface according to FIG. 2) of the first reflective optical element 15a. The second reflective optical element 15b is inclined such that the light entering from the first reflective optical element 15a is reflected by the internal reflection surface so that it gradually separates forward with respect to the optical axis of the optical repeater 14. (Slightly lower left according to FIG. 2).
The material of the second reflective optical element 15b is a material having a refractive index equivalent (substantially equivalent) to that of the first reflective optical element 15a. For example, quartz glass or another glass material is used.

The lens 16 is bonded to the emission side surface (front end surface) of the second reflective optical element 15b. The lens 16 is a lens that condenses the light incident from the second reflective optical element 15b, and is configured by, for example, a cylindrical rod lens.
The material of the lens 16 is a material having a refractive index equivalent (substantially equivalent) to that of the second reflective optical element 15b. For example, quartz glass or other glass material is used.

  Joining of two members arranged in the optical path direction, such as the optical repeater 14 and the first reflective optical element 15a, the first reflective optical element 15a and the second reflective optical element 15b, the second reflective optical element 15b and the lens 16 As the adhesive used in the above, a translucent adhesive having a refractive index equivalent to those of these two members is used. As a specific example of this adhesive, a thermosetting acrylic UV adhesive can be used. It has been experimentally confirmed that the adhesive has a refractive index equivalent to that of the two members by appropriately adjusting the components.

  Here, more specifically, the refractive indexes of the optical repeater 14, the first reflective optical element 15a, the second reflective optical element 15b, the lens 16, and the adhesive used for joining them are substantially equal. Among these, the difference in the refractive index between the adhesive having the maximum refractive index and the adhesive having the minimum refractive index is preferably 0.01 or less.

  The second rotating element 20 includes a cylindrical case 21 in which the optical repeater 14 is rotatably rotatable, a second optical path conversion unit 22 fixed to the front end side of the cylindrical case 21, and the rear of the cylindrical case 21. A support member 23 that supports the end side and a tubular body 24 that is inserted and fixed in the center of the support member 23 are provided, and are configured to rotate integrally.

  The cylindrical case 21 is formed in a substantially cylindrical shape from a metal material, hard synthetic resin, or the like, and has a notch 21a that partially penetrates the peripheral wall in the circumferential direction on the front end side of the peripheral wall.

The second optical path conversion unit 22 is disposed on the emission direction side of the first optical path conversion unit 15 so as to correspond to the notch 21 a and is fixed to the inner wall surface on the front end side of the cylindrical case 21.
The second optical path conversion unit 22 is, for example, a glass reflector, and the reflection surface 22a is disposed on the path of light emitted forward from the lens 16. As shown in FIG. 2, the light incident on the second optical path changing unit 22 from the lens 16 side is reflected by the reflecting surface 22 a and is directed in a direction intersecting the optical axis of the lens 16.

The support member 23 is a cylindrical member fixed coaxially inside the rear end side of the cylindrical case 21. The support member 23 is made of, for example, a metal material or a hard synthetic resin.
A tube body 24 is inserted through and fixed to the center of the support member 23.

The tubular body 24 is a long cylindrical member made of a hard metal material, ceramic, or the like, and is formed to be slightly larger than the tubular body 13 described above. The tubular body 24 is inserted into the central portion of the tubular body 24 in a penetrating manner with a radial gap.
The rear end side of the tube body 24 is elongated in a rearward direction from the rear end surface of the support member 23 and functions as a rotation shaft of a first rotation drive source 30 described later.

  The first rotational drive source 30 includes a rotatable rotor 31, an electromagnetic coil 32 that covers the periphery of the rotor 31, a cylindrical housing 33 (stator) that covers the periphery of the electromagnetic coil 32, and a housing Bearing members 34 and 35 provided on the front side and the rear side in 33 (see FIG. 1), and an inner rotor type rotary electric motor that rotates the rotor 31 by supplying power to the electromagnetic coil 32 is configured. Yes.

The rotor 31 is configured in a cylindrical shape having a permanent magnet, and continuously rotates by a magnetic action with the electromagnetic coil 12. A through hole 31 a that is continuous in the axial direction is provided at the center of the rotor 31.
Further, the tube body 24 is connected to the front portion side of the rotor 31 so as to communicate with the through hole 31a, and the tube body 25 is also connected to the rear end portion side of the rotor 31 so as to communicate with the through hole 31a. Is connected.
The tubular body 13 containing the optical fiber F2 is inserted in the tubular body 24, the through hole 31a, and the tubular body 25 so as to have a gap in the radial direction.

  The electromagnetic coil 32 is provided in a substantially cylindrical shape with a predetermined clearance with respect to the outer peripheral surface of the rotor 31, and is fixed to the inner peripheral surface of the housing 33 so as not to rotate.

  The housing 33 (stator) is formed in a cylindrical shape from a magnetic material (for example, permalloy or the like), and the bearing members 34 and 35 are fixed to the inner peripheral surfaces of the front end side and the rear end side, respectively.

The front bearing member 34 is rotatably inserted through the tube body 24.
Similarly, the rear bearing member 35 is inserted through the tube body 25 and rotatably supported. The bearing member 35 projects rearward from the housing 33, and a second rotational drive source 40, which will be described later, is connected to the projecting portion.

The second rotational drive source 40 includes a rotatable rotor 41, an electromagnetic coil (not shown) that covers the periphery of the rotor 41, and a cylindrical housing 42 (stator) that covers the periphery of the electromagnetic coil. And bearing members 43 and 44 provided on the front side and the rear side in the housing 42 (see FIG. 1), and in the same manner as the first rotation drive source 30, the rotor 41 is supplied with power supplied to the electromagnetic coil. An inner rotor type rotary motor that rotates the motor is configured.
This second rotational drive source 40 is connected to the bearing 42 of the first rotational drive source 30 via the connecting member 45 by connecting the rear end portion of the housing 42 and the bearing member 43 to the first rotational drive source 40. The drive source 30 is coaxially connected to the rear side.

  A through hole that is continuous in the axial direction is provided at the center of the rotor 41, and the tubular body 13 containing the optical fiber F2 is inserted into the through hole in a through shape and fixed.

  The front bearing member 43 is inserted into the tube 13 and rotatably supported. Similarly, the rear bearing member 44 is rotatably inserted through the tube body 13. The bearing member 44 projects rearward from the housing 42, and the optical fiber F1 and the light correction member f1 are connected to the projecting portion through a cylindrical connection member or the like so as not to rotate.

  The first rotary drive source 30 and the second rotary drive source 40 having the above-described configuration are controlled by control circuits (not shown) so that the first rotary element 10 and the second rotary element 20 rotate at different speeds. Has been. Preferably, the first rotation drive source 30 and the second rotation drive source 40 are controlled so that the ratio between the rotation speed of the first rotation element 10 and the rotation speed of the second rotation element 20 does not become an integral multiple. .

Next, the characteristic operation and effect of the optical imaging probe 1 having the above configuration will be described in detail.
The optical imaging probe 1 is used by being inserted into a cylindrical detection portion X, for example, as shown in FIG. When light is supplied from an optical imaging apparatus (not shown) to the optical fiber F1 on the rear side of the optical imaging probe 1, this light passes through the optical correction member f1, the gap s, the optical fiber F2, and the like, and the optical relay unit 14 Enter. Further, this light passes through the optical repeater 14, is reflected twice within the first optical path converter 15, and is emitted from the front end surface of the lens 16. Then, the emitted light is reflected by the second optical path changing unit 22 as shown in FIG. 2 and is irradiated on the inner peripheral surface of the cylindrical detected portion X.
The irradiation light also moves in the circumferential direction while reciprocating in the axial direction on the inner circumferential surface of the detected part X by the rotation of the first rotating element 10 and the second rotating element 20.

Moreover, the light irradiated to the to-be-detected part X is reflected on the surface of the to-be-detected part X, the 2nd optical path conversion part 22, the lens 16, the 1st optical path conversion part 15, the optical relay part 14, and the optical fiber F2. , F1 and the like are passed in the reverse direction.
In particular, the light in the reverse direction enters the inclined surface 14a at the front end of the optical relay unit 14 from the first reflective optical element 15a, but the refractive indexes of the first reflective optical element 15a and the optical relay unit 14 are equivalent. In addition, since the refractive index of the adhesive that bonds between them is equivalent, it is difficult to cause a loss of light amount due to reflection at the boundary surface between them.

Further, since the optical repeater 14 and the first optical path changer 15 have the same area and the same polygonal end face, the optical repeater 14 and the first optical path changer 15 are manufactured in the manufacturing stage of the optical imaging probe 1. When joining the two, the work of aligning the optical axes of these two members can be facilitated.
Further, since the optical path is bent in a substantially crank shape by the first optical path conversion unit 15 including two prisms, the axial length of the lens 16 and the axial length of the optical path can be shortened. As a result, the entire optical imaging probe 1 can also be made relatively short.
In addition, since both the first optical path conversion unit 15 and the second optical path conversion unit 22 are rotated to change the irradiation trajectory in the axial direction and the circumferential direction, a relatively wide scan area is ensured. Can do.

Next, an optical imaging probe 2 that is another embodiment of the present invention will be described (see FIG. 3).
This optical imaging probe 2 replaces the above-described optical imaging probe 1 by replacing the cylindrical case 21 with the cylindrical case 21 'and replacing the second optical path conversion unit 22 with the second optical path conversion unit 22'. Therefore, the changed part will be mainly described in detail, and the overlapping parts are denoted by the same reference numerals as those of the optical imaging probe 1 and description thereof will be omitted.

The cylindrical case 21 ′ is formed in a substantially cylindrical shape in which the cutout portion 21a is omitted from the cylindrical case 21.
The second optical path conversion unit 22 ′ is a glass lens having a shape in which one end side of a cylindrical body is cut by a plane orthogonal to the central axis and the other end side is cut by a plane inclined to the central axis ( (See FIG. 3). The second optical path conversion unit 22 is coaxially fixed to the front end side in the cylindrical case 21 ′ so that the orthogonal plane faces the light source side.

According to the optical imaging probe 2 configured as described above, the light emitted from the front end surface of the lens 16 is refracted by the second optical path changing unit 22 ′ as shown in FIG. Irradiate the surface.
The irradiation light reciprocates in the radial direction while circularly moving on the surface of the detected part X ′ by the rotation of the first rotating element 10 and the second rotating element 20.

Further, the light reflected by the surface of the detected portion X ′ travels in the reverse direction and passes from the first reflective optical element 15a to the optical repeater 14 in the same manner as the optical imaging probe 1 described above. At the time of this passage, the refractive index of the first reflective optical element 15a and the optical relay unit 14 is equivalent, and the adhesive bonding between them is also equivalent in refractive index. It is possible to reduce the loss of light amount due to the reflection.
Therefore, the optical imaging probe 2 can obtain substantially the same effect as the optical imaging probe 1.

  In addition, according to the said Example, although it was set as the structure which rotates the 1st optical path conversion part 15 and the 2nd optical path conversion part 22, as another example, the 1st optical path conversion part 15 and the 2nd optical path conversion It is also possible to configure an optical imaging probe in which one or both of the sections 22 are not rotated. In this optical imaging probe, the refractive index of the first reflective optical element 15a and the optical relay section 14 is also possible. In addition, by making the refractive indexes of the adhesives equivalent, loss of light amount can be reduced.

DESCRIPTION OF SYMBOLS 1, 2: Probe for optical imaging 10: 1st rotation element 14: Optical relay part 15: 1st optical path conversion part 15a: 1st reflection optical element 15b: 2nd reflection optical element 20: 2nd rotation element 22 , 22 ': second optical path conversion unit 30: first rotation drive source 40: second rotation drive source X: detected portion F1, F2: optical fiber

Claims (6)

Light incident from the optical fiber is transmitted through the optical path conversion unit, converted into an optical path, irradiated to the detected unit, and the light reflected by the detected unit is reflected on the optical path conversion unit and the optical fiber through a path reverse to the irradiation. In the optical imaging probe that is allowed to pass through,
Between the optical fiber and the optical path conversion unit, there is provided an optical relay unit that transmits light between them and has a uniform internal refractive index. The optical relay unit and the optical path conversion unit have a refractive index. A probe for optical imaging, characterized in that it is formed of an equivalent material and bonded.   2. The optical imaging probe according to claim 1, wherein the optical repeater is formed in a long shape along the optical axis of the optical fiber and is coaxially joined to the front end of the optical fiber.   The optical path conversion unit includes a first reflective optical element that reflects light incident from the optical relay unit side in a direction intersecting the incident direction, and light incident from the first reflective optical element side. 3. The optical imaging probe according to claim 1, wherein a second reflective optical element that reflects in a direction crossing the incident direction is joined.   The optical imaging according to any one of claims 1 to 3, wherein a translucent adhesive having a refractive index equivalent to that of these two members is used for joining the optical repeater and the optical path changer. Probe.   The light according to any one of claims 1 to 4, wherein two members arranged in the optical path direction have a polygonal shape having the same area as a joint end surface of one member and a joint end surface of the other member. Imaging probe. The optical path conversion unit is a first optical path conversion unit, and on the emission direction side of the first optical path conversion unit, a second optical path conversion unit that optically converts the light emitted by the first optical path conversion unit,
The optical repeater, the first optical path changer, and the second optical path changer are each supported so as to rotate around the optical axis of the optical repeater,
A first rotation drive source that rotates the optical repeater and the first optical path conversion unit, and a second rotation drive source that rotates the second optical path conversion unit, respectively,
By controlling the first rotation drive source and the second rotation drive source, respectively, the rotation speed of the optical relay unit and the first optical path conversion unit and the rotation speed of the second optical path conversion unit are made different. The optical imaging probe according to claim 1, wherein the probe is for optical imaging.

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