JP3104984B2 - Optical scanning device for tomographic image observation - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical scanning device for tomographic image observation that scans light for tomographic image observation and facilitates visualization of internal information of a subject.

[Prior Art] In recent years, the use of images in medical treatment has become widespread, and the importance of a technique for non-invasively and non-contactly measuring internal information of a subject has been increasing.

Conventionally, non-invasive, non-contact measurement of information inside a subject such as a living body has been mainly performed by X-rays.
The use of X-rays has the problems of exposure to radiation and the difficulty of imaging biological functions, and fluoroscopy of tissue in body cavities has been performed with an ultrasonic endoscope.

However, the ultrasonic endoscope does not have a very high spatial resolution and cannot know information such as a physiological composition other than the form. Further, when the ultrasonic endoscope is used, a medium such as water is required, so that there is a problem that a procedure for observing the subject is complicated.

For this reason, recently, various technologies relating to optical CT for visualizing information inside a subject using light have been proposed. For example, Japanese Patent Application Laid-Open No. HEI 1-209342 discloses the prior art.

[Problems to be Solved by the Invention] In the tomographic image observation by the optical CT or the like, an insertion portion for guiding light for tomographic image observation is inserted into the subject, and the insertion portion is bent and operated. It is necessary to perform optical scanning properly.

However, conventionally, when a tomographic image of an observation site located on the outer periphery of the insertion portion is to be obtained, a complicated bending operation of the insertion portion is required, and there is a possibility that optical scanning may be inappropriate.

Furthermore, when the space inside the subject into which the insertion portion can be inserted is extremely narrow, for example, the movement of the insertion portion is restricted, so that appropriate optical scanning cannot be performed, and a desired tomographic image may not be obtained. There is.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an optical scanning device for tomographic image observation that can perform scanning of light necessary for tomographic image observation with a simple operation and reliably. Aim.

[Means and Actions for Solving the Problems] An optical scanning device for tomographic image observation according to the present invention includes an insertion portion to be inserted into a subject, a rotatable shaft inserted through the insertion portion, and a rotatable shaft. An optical fiber that is inserted and guides light for tomographic image observation; and a deflecting unit that is provided at a distal end of the shaft and deflects light for tomographic image observation guided by the optical fiber. And a motor disposed on the base end side of the shaft for rotating the shaft; detection means for detecting reflected light at each position of the observation part; and light of the observation part based on the output of the detection means. And a calculating means for constructing a tomographic image.The tomographic image observing optical scanning device according to the present invention is further provided on the shaft on the side of the observing site relative to the deflecting means, Deflection by deflection means Characterized by comprising a lens for light distribution of the light.

Further, the optical scanning device for tomographic image observation according to the present invention further outputs an encoder connected to the motor and scanning position information to which a signal from the encoder is input, and based on a signal from the encoder, A control circuit for driving the motor at a constant rotation speed, and the arithmetic means is based on the output of the control circuit and the detection means,
It is characterized in that an optical tomographic image of the observation site is constructed.

Further, an optical scanning device for tomographic image observation according to the present invention comprises: an elongated insertion portion to be inserted into a subject; a plurality of optical fibers arranged annularly along the outer periphery of the insertion portion; Scanning means for sequentially entering light for the plurality of optical fibers for scanning, sequentially emitting from the tip of the plurality of optical fibers, and detecting means for detecting reflected light at each position of the observation site, Calculating means for constructing an optical tomographic image of the observation site based on the output of the detecting means.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to the drawings.

1 to 3 show a first embodiment of the present invention. FIG. 1 is a schematic configuration diagram of an optical scanning device for tomographic image observation, FIG. 2 is an explanatory diagram showing the arrangement of optical fibers, and FIG. FIG. 4 is an explanatory view showing a tip shape of an optical fiber.

As shown in FIG. 1, an optical scanning device for observing a tomographic image includes an elongated flexible insertion portion 1 which is inserted into a subject.
And a light transmitting / receiving device 3 that emits light for tomographic image observation and receives reflected light from inside the subject, a galvanometer 4, and a control circuit 5 that controls the galvanometer 4.

The insertion section 1 is configured as, for example, an insertion section of an endoscope, and an illumination window 7, an observation window 8, a suction channel 9, and the like are formed in a channel portion 6a of the distal end portion 6.

A light distribution lens (not shown) is mounted inside the illumination window 7, and a light guide 10 is connected to the rear end of the light distribution lens. The light guide 10 is inserted through the inside of the insertion section 1 and connected to a light source device (not shown). The light guide 10 transmits irradiation light from the light source device to irradiate the observation portion of the subject from the illumination window 7. ing.

An objective lens (not shown) is provided inside the observation window 8, and a distal end surface of the image guide 11 is arranged at an image forming position of the objective lens. This image guide
Reference numeral 11 is inserted through the insertion section 1 and has a rear end face facing an eyepiece in an eyepiece (not shown). Then, the optical image of the observation site formed by the objective lens is guided by the image guide 11, and the naked eye can be observed from the eyepiece.

The insertion section 1 is provided with an optical fiber bundle 2 as a means for radially scanning light for tomographic image observation. The optical fiber bundle 2 is provided with a plurality of optical fibers on the outer peripheral side of the insertion section 1. 12 are arranged in a ring.

As shown in FIG. 2, the distal end of the optical fiber 12 is disposed on the outer peripheral side of the distal end portion 6 so as to surround the channel portion 6a, and as shown in FIG. For example, it is cut to 45 ° and the tapered surface 12a
Are formed.

Then, aluminum, silver, gold, or the like is vapor-deposited on the tapered surface 12a to form a mirror surface, and the mirror surface is arranged so as to be inward at the tip of the insertion portion 1. Light is emitted to the side of the fiber axis, and reflected light reflected from the inside of the subject enters the fiber axis direction.

Further, inside the light transmitting and receiving device 3, for example, a pulse laser for emitting a light pulse in picosecond units, a lens and a mirror group for forming an optical path of the light pulse emitted from the pulse laser, and an image pickup unit And so on.

When an optical pulse is emitted from the pulse laser of the light transmitting and receiving device 3, the swing angle of the mirror 4a of the galvanometer 4 is controlled by the control circuit 5 in conjunction with the emission of the optical pulse, and the optical fiber bundle 2 The light is incident on each optical fiber 12.

Incidentally, the optical fiber 12 may be provided with a prism without forming the tapered surface 12a at the end, and, instead of the optical fiber 12, as shown in FIG. The optical fiber bundle 2 may be constituted by using an optical fiber 13 bent outward from the portion 1.

Next, optical tomographic image observation using the optical scanning device for tomographic image observation will be described.

For example, when observing an optical tomographic image of an affected part of a human body organ,
First, the insertion section 1 is inserted into the body cavity. Next, when the outer peripheral side of the distal end portion 6 reaches the affected part position, an optical pulse having a very short time width with a half width of several picoseconds is generated from the pulse laser in the light transmitting and receiving device 3, and this optical pulse is transmitted to the mirror 4 a of the galvanometer 4. And is incident on each optical fiber 12 constituting the optical fiber bundle 2.

The light pulse incident on each of the optical fibers 12 is reflected by the tapered surface 12a at the tip and emitted to the side of the fiber axis,
Optical scanning is performed radially outward from the optical fiber bundle 2. When the light applied to the affected part is reflected on the tissue surface and inside, the reflected light is guided from the optical fiber bundle 2 through the mirror 4a of the galvanometer 4 into the light transmitting and receiving device 3, and Through a group of lenses and mirrors described above, for example, into an imaging means such as a streak camera.

In the streak camera, a time-resolved waveform of the reflected light is detected, and the time-resolved waveform is processed by a processing device (not shown) to obtain a tomographic image of an observation site and displayed on a display device (not shown).

That is, when observing a tomographic image by inserting the insertion portion 1 into the subject, the distal end portion 6 of the insertion portion 1 can be inserted into the observation site without complicated bending operation of the insertion portion 1. By simply performing the light scanning, the light scanning is performed radially from the insertion section 1, so that a tomographic image of a desired observation site can be easily obtained.

Instead of the galvanometer 4, as shown in FIG. 5, between the optical fiber bundle 2 and the light transmitting / receiving device 3,
AOM (acousto-optic element) 14 is arranged and this AOM 14 is used as a control circuit.
By controlling in step 15, scanning from the light transmitting and receiving device 3 may be controlled.

6 and 7 show a second embodiment of the present invention.
The figure is a system configuration diagram for optical tomographic image observation, and FIG. 7 is an explanatory diagram showing a probe holding balloon.

In the second embodiment, optical scanning is performed mechanically by using a single fiber in the first embodiment.

As shown in FIG. 6, the system for optical tomographic image observation includes a probe 21, an optical tomographic processing control unit 22, an image processing device 23, and a control circuit 24 for controlling the optical scanning drive of the probe 21. It has.

The probe 21 has an elongated and flexible insertion section 25 to be inserted into the subject, and a wide operation section 26 provided on the base side of the insertion section 25. A cylindrical translucent cover 27 having a closed front end is mounted on the front end side.

A flexible shaft 29 containing an optical fiber 28 connected to the optical tomography processing control unit 22 is inserted substantially on the axis of the insertion unit 25.
The tip side of 29 is rotatably supported by a bearing 30.
The optical fiber 28 is connected to the flexible shaft 29.
, And the optical fiber 28 and the flexible shaft 29 may be rotated simultaneously. further,
At the tip of the flexible shaft 29 exposed in the translucent cover 27, a mirror 31 having an inclination angle of, for example, 45 ° with respect to the axis of the flexible shaft 29, and reflected light from the mirror 31 are distributed. And a lens 32 are provided.

A gear 33 is externally fitted and fixed to the operation section 26 side of the flexible shaft 29, and a gear 34 meshes with the gear 33. The gear 34 is fixed to an output shaft of a motor 35, and an encoder 36 is connected to the motor 35.
The control circuit 24 is connected to the motor 35, and a signal from the encoder 36 is input to the control circuit 24 to control the rotation of the motor 35.

The optical tomographic processing control unit 22 includes, for example, a dye laser and Nd: Y
A pulse laser 37 in combination with an AG laser is provided, and the emitted light of the Nd: YAG laser is applied to a dye (for example, Rhodamine 6G) in a dye laser. Splitter
39 separates them into two.

The light transmitted through the beam splitter 39 is further transmitted through the beam splitter 40 and condensed by a lens 41.After being incident on the optical fiber 28 of the probe 21, the light is irradiated on an observation site through the optical fiber 28. You. The reflected light from the observation site passes through the lens 41, is reflected by the beam splitter 40, passes through the beam splitter 42, and
It is incident on a nonlinear optical element such as 3.

On the other hand, the light emitted from the pulse laser 37 and reflected by the beam splitter 39 is reflected by the mirrors 44a and 44b of the delay mirror device 44, is reflected by the beam splitter 42 via the mirror 45, and is used as the reference light by the KDP 43. To be incident on.

The KDP 43 generates a second harmonic by inputting the reflected light from the observation site and the reference light. The second harmonic passes through a filter 46 and is detected by a photomultiplier tube 47. The filter 46 has a second harmonic when the wavelength of the light emitted from the pulse laser 37 is λ.
It has a characteristic of passing a narrow band including the wavelength λ / 2 which is a harmonic.

In the delay mirror device 44, mirrors 44a and 44b facing each other are fixed to a movable stage 44c, and a moving device 44d for moving the movable stage 44c is driven by a motor 44e to change the optical path length of the reference light. It has become.

Since the intensity of the second harmonic generated by the KDP 43 is proportional to the integral value of the product of the reflected light and the reference light when the reflected light and the reference light are each a function of time, the mirrors 44a, 44
By moving b to change the optical path length of the reference light, the intensity of an arbitrary time component of the reflected light from the inside of the observation site can be detected by the photomultiplier 47.

The output of the photomultiplier tube 47 is input to the image processing device 23, in which the output of the photomultiplier tube 47 is highly sensitive by combining a synchronous detection amplifier and a DC ammeter. A lock-in amplifier 48 that detects an analog signal from the lock-in amplifier 48 and converts it into a digital signal.
A D converter 49 and a computer 50 that processes digital signals from the A / D converter 49 and performs image processing on an optical tomographic image of an observation site are provided.

 Next, the operation of the present embodiment will be described.

The insertion portion 25 of the probe 21 is inserted into a subject such as a living body, and the distal end side of the insertion portion 25 is positioned at an observation site. Emit a pulse. This light pulse passes through the beam splitters 39 and 40 and passes through the lens 41 to the optical fiber 2.
8, the light is guided through the optical fiber 28, and is emitted from the end face.

The light pulse emitted from the optical fiber 28 is reflected by the mirror 31 at the tip of the flexible shaft 29 exposed in the translucent cover 27, emitted to the side of the insertion portion 25 via the lens 32, and then to the observation site. Irradiated.

Then, when the irradiated light pulse is reflected on the boundary surface of the living tissue surface and the inside having a different refractive index, the reflected light pulse is guided to the optical tomographic processing control unit 22 by the optical fiber 28 and the lens 41 And is reflected by the beam splitter 49, passes through the beam splitter 42, and KD
It is incident on P43.

At this time, the light pulses emitted from the pulse laser 37 and separated by the beam splitter 39 are reflected by mirrors 44a and 44b.
The light is guided to a beam splitter 45 → a beam splitter 42, is reflected by the beam splitter 42, and is incident on the KDP 43 as reference light.

The second harmonic generated by the KDP 43 is detected by a photomultiplier tube 47 via a filter 46, further converted into a digital signal by an A / D converter 49 via a lock-in amplifier 48, and input to a computer 50. .

At the same time, the motor 35 incorporated in the operation unit 26 of the probe 21 is feedback-controlled by the control circuit 24 based on the output of the encoder 36, and is rotated at a constant rotation speed. The rotation of the motor 35 is transmitted to the flexible shaft 29 via gears 33 and 34, and the mirror 31 at the tip of the flexible shaft 29 is rotated.

When the light scanning is performed radially from the insertion section 25 and the above operation is repeated, the intensity of the time component of the reflected light at each position of the observation region is detected, and the scanning position information from the control circuit 24 is detected. The processing is performed by the computer 50. As a result, an optical tomographic image of the observation site is constructed and displayed on a display (not shown).

Also in the second embodiment, similarly to the first embodiment, when observing an optical tomographic image, an optical tomographic image of a desired observation site can be easily obtained without requiring a complicated bending operation of the insertion section 25. Can be.

When observing an optical tomographic image using the probe 21, it is desirable to use a probe holding balloon 51 attached to the insertion portion 25, as shown in FIG.

In this case, the insertion portion 25 is inserted into the subject, and when the distal end portion reaches the observation site, the position of the insertion portion 25 is not shifted by blowing air from the air supply / discharge channel 52 to the balloon 51. This has the advantage that the noise can be reduced and the S / N ratio can be improved with respect to the integrated value when the intensity of the reflected light from the inside of the subject is small.

FIG. 8 et seq. Show a third embodiment of the present invention, FIG. 8 is a configuration diagram of an endoscope apparatus for observing an optical tomographic image, FIG. 9 is a system configuration diagram, and FIG. It is sectional drawing which shows the structure of a tube.

As shown in FIG. 8, the endoscope device includes an endoscope 60, a light source device 61 to which the endoscope 60 is connected, and a video processor 6.
2 and an optical tomographic processing device 63, and a monitor 64 connected to the video processor 62.

The endoscope 60 has an elongated and flexible insertion portion 65,
An operation section 66 is provided at the rear end of the insertion section 65, and a universal cord 67 extends from a side of the operation section 66.

A light guide (not shown) for transmitting illumination light from the light source device 61 is inserted into the universal cord 67, and an end of the universal cord 67 is detachably connected to the light source device 61. A light source connector 68 is provided. A signal cable 69 extends from the light source connector 68, and a signal connector 70 detachably connected to the video processor 62 is provided at an end of the signal cable 69.

The operating section 66 is provided with a bending operation knob 71 for bending the bending section provided on the insertion section 65 and a light guide driving section 72.
The optical tomographic processing device 63 and the optical tomographic processing device 63 are connected via a ride guide 73.

An observation window 75 is provided on the side of the distal end 74 of the insertion section 65.
And two illumination windows 76 are provided, and a cylindrical translucent cover 77 having a closed front end is attached to the front end of the front end 74.

Further, a channel 78 is provided in the insertion section 65 and the operation section 66, the leading end side communicating with the inside of the translucent cover 77, and the rear end side connected to the light guide driving section 72.

As shown in FIG. 9, an objective lens 79 is provided inside the observation window 75, and a CCD 80 is provided at an image forming position of the objective lens 79, and a driving circuit 81 is connected to the CCD 80. . The signal line 82 connected to the drive circuit 81
Is inserted through the insertion section 65, the operation section 66, the universal cord 67, the light source connector 68, and the signal cable 69, is connected to the signal connector 70, and is connected to the video processor 62 via the signal connector 70. ing.

A light guide 83 for observing an optical tomographic image is inserted into the channel 78. This light guide
A prism 84 disposed inside the translucent cover 77 and having an optical axis directed to the side of the distal end portion 74 is fixed to the distal end surface of the 83.

On the other hand, the rear end of the light guide 83 is introduced into the light guide driving section 72, and a cylindrical base 85 is fixed to the rear end of the light guide 83 in the light guide driving section 72. Have been. A bearing for rotatably supporting the base 85 is provided in the light guide driving section 72.
86 is provided, a gear 87 is externally fitted and fixed to the base 85,
A gear 88 meshes with the gear 87.

The gear 88 is fixed to an output shaft of a first pulse motor 89, and the first pulse motor 89 and the bearing 86 are fixed to a rack 90. In addition, this rack 90
Pinion 92 fixed to the output shaft of second pulse motor 91
Are engaged.

Therefore, by rotating the first pulse motor 89, the light guide 83 rotates, and by rotating the second pulse motor 91, the light guide 83 moves forward and backward through the rack 90. Has become.

Further, in the optical tomographic processing apparatus 63, a pulse laser 37, a KDP 43, a filter 46, a photomultiplier 47, an image processing apparatus 23, and the like, which are the same as those in the second embodiment, are provided. Is incident on a group of laser mirrors in the light guide driving unit 72 via an optical fiber bundle 73a in the light guide 73.

In this group of laser mirrors, as in the second embodiment, the pulse laser is
The light emitted from 37 is split into two, and the light transmitted through the beam splitter 39 is further transmitted through the beam splitter 40, enters the light guide 83, and irradiates an observation site inside the subject. Has become.

Further, the reflected light from the observation site is guided from the light guide 83 to the beam splitter 40, is reflected by the beam splitter 40, passes through the beam splitter 42, and passes through the optical fiber bundle 73b in the light guide 73. Through KDP
43.

On the other hand, the light emitted from the pulse laser 37 and reflected by the beam splitter 39 is reflected by the mirrors 44a and 44b of the delay mirror device 43, further reflected by the beam splitter 42 via a mirror 45, and The light is incident on the KDP 43 as reference light via the bundle 73b.

Then, as in the above-described second embodiment, the second harmonic from the KDP 43 passes through the filter 46, is detected by the photomultiplier 47, passes through the lock-in amplifier 48, the A / D converter 49, and the computer 50. Image processing is performed.

The image signal processed by the computer 50 is input to, for example, a superimposing circuit in the video processor 62. In the superimposing circuit, the signal of the endoscope image and the signal of the optical tomographic image are synthesized. , Monitor 64
To be displayed.

As shown in FIG. 10, the light guide 83 includes a second outer tube 95 for covering the optical fiber bundle 94 of the light guide 83 in a first outer tube 93 attached to the base 85. The outer diameter D2 of the second outer tube 95 and the first outer tube 93
Is set to be substantially the same as the thickness t of the second exterior tube 95. Thereby, the movement in the axial direction at the time of bending is ensured, the durability of the optical fiber bundle 94 is improved, and breakage or the like can be prevented.

 Next, the operation of the present embodiment will be described.

Illumination light from the light source device 61 is applied to a subject, for example, an organ 96 from a light guide (not shown) in the universal cord 67 via an illumination window 76. The optical image of the organ 96 is captured by the CCD 80. An output signal of the CCD 80 is processed by a video signal processing circuit in a video processor 62, and a video signal from the video signal processing circuit is input to a monitor 64 via a superimposing circuit, and an endoscopic image is output to the monitor 64. Is displayed.

On the other hand, when observing an optical tomographic image of the living tissue 97 of the organ 96, first, the pulse laser in the optical tomographic processing device 63 is used.
Generate a light pulse of several picoseconds from 37. This light pulse passes through the beam splitters 39 and 40 and passes through the light guide 83.
, And irradiates the living tissue 97 of the organ 96 from the light guide 83 via the prism 84.

Then, with respect to the irradiated light pulse, a reflected light pulse reflected on the boundary surface having a different refractive index in the living tissue 97 is guided via the light guide 83 via the same light path as in the second embodiment described above. The light is incident on the KDP 43 together with the reference light.

The second harmonic from the KDP 43 is detected by the photomultiplier tube 47, and the above operation is repeated while scanning the observation position by moving the light guide 83 forward and backward by the light guide driving unit 72, thereby obtaining the biological tissue. Data necessary for constructing 97 optical tomographic images is acquired.

The data is processed by the optical tomographic processing device 63 to construct an optical tomographic image, and the superimposing circuit in the video processor 62 combines the endoscope image and the optical tomographic image and displays them on the monitor 64. .

As described above, according to the present embodiment, it is possible to observe the optical tomographic image of the living tissue 97 together with the normal endoscopic image observation. Other operations and effects are the same as those of the above-described embodiments.

[Effects of the Invention] As described above, according to the present invention, since the insertion portion inserted into the subject is provided with the means for radially scanning light for tomographic image observation from the insertion portion, optical scanning can be performed. There is an effect that it can be easily performed and a tomographic image can be reliably obtained.

[Brief description of the drawings]

1 to 3 show a first embodiment of the present invention, FIG. 1 is a configuration diagram of an optical scanning device for observing a tomographic image, FIG. 2 is an explanatory diagram showing an arrangement of optical fibers, and FIG. 4 and 5 show a modified example, FIG. 4 is an explanatory view showing the tip shape of the optical fiber, and FIG. 5 is a configuration of an optical scanning device for tomographic image observation. FIGS. 6, 6 and 7 show a second embodiment of the present invention, FIG. 6 is a system configuration diagram for optical tomographic image observation, FIG. 7 is an explanatory diagram showing a probe holding balloon, FIG. The following shows a third embodiment of the present invention, FIG. 8 is a configuration diagram of an endoscope apparatus for optical tomographic image observation, FIG. 9 is a system configuration diagram, and FIG. 10 is a configuration of an optical fiber outer tube. FIG. DESCRIPTION OF SYMBOLS 1 ... Insertion part 2 ... Optical fiber bundle 3 ... Transmitting / receiving apparatus 4 ... Galvanometer 5 ... Control circuit

Continuing on the front page (72) Inventor Shuichi Takayama 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-Limpus Optics Industry Co., Ltd. (72) Inventor Ichiro Nakamura 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-Limpus Optics Within Kogyo Co., Ltd. (72) Inventor Kazunari Nakamura 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-limpus Optical Co., Ltd. (72) Eiichi Fuse 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-limpus Optical Industry Co., Ltd. (72) Inventor Susumu Takahashi 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-limpus Optical Industry Co., Ltd. (72) Inventor Yoshihiro Kosaka 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-limpus Inside Optical Industry Co., Ltd. (72) Inventor Hiromasa Suzuki 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Industry Co., Ltd. (56) References JP-A-62-155827 (JP, A) JP-A-63 -26555 (JP, A) JP-A-63-85417 (JP, A) (58 ) Field surveyed (Int. Cl. ⁷ , DB name) A61B 10/00 A61B 1/00

Claims (4)

(57) [Claims] An insertion part to be inserted into a subject, a rotatable shaft inserted through the insertion part, and a light provided through the shaft to guide light for tomographic image observation. A fiber, provided at the distal end of the shaft, a deflecting unit that deflects light for tomographic image observation guided by the optical fiber, and is disposed on the proximal end side of the shaft,
A motor for rotating the shaft, detection means for detecting reflected light at each position of the observation site, and calculation means for constructing an optical tomographic image of the observation site based on the output of the detection means. Characteristic optical scanning device for tomographic image observation. 2. A tomographic image according to claim 1, further comprising a lens provided on said shaft on an observation site side of said deflecting means, and for distributing the light deflected by said deflecting means. Optical scanning device for observation. 3. An encoder connected to the motor, a control circuit receiving a signal from the encoder, outputting scanning position information, and driving the motor at a constant rotation speed based on a signal from the encoder. And with
The optical scanning device for tomographic image observation according to claim 1, wherein the arithmetic unit constructs an optical tomographic image of an observation site based on outputs from the control circuit and the detection unit. 4. An elongated insertion portion to be inserted into a subject, a plurality of optical fibers arranged annularly along the outer periphery of the insertion portion, and a plurality of light beams for observing tomographic images. Scanning means for sequentially entering the fiber, sequentially emitting and scanning from the tips of the plurality of optical fibers, detecting means for detecting reflected light at each position of the observation site, and based on the output of the detecting means, An optical scanning device for observing a tomographic image, comprising: an arithmetic unit configured to construct an optical tomographic image of an observation site.