JP2008173395A - Endoscope system and method of detecting shape of insertion part of endoscope used therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive endoscope system having excellent assembling property, detecting the three-dimensional shape of an insertion part by obtaining the information on the distortion from Fiber Bragg Grating without using an optical coupler and capable of being miniaturized; and a method of detecting the shape of the insertion part of the endoscope used therein. <P>SOLUTION: The endoscope system 1 comprises the insertion part 5 to be inserted into the space to be examined; an optical fiber 12 inserted into the insertion part 5 to constitute an FBG sensor λ in which a plurality of Bragg grating parts 42 are formed; a light source device 23 for introducing incident light into one end of the optical fiber 12; a detection part 26 for receiving the incident light transmitted inside the optical fiber 12, transmitting the Bragg grating parts 42 and emitted from the other end of the optical fiber 12 as transmitted light; and a control device 3 for computing the Bragg wavelength defect information and the quantity of deviation of the Bragg wavelength in the transmitted light and detecting the quantity of distortion of the optical fiber 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention, for example, detects the bending shape in a state where the insertion portion of the endoscope is inserted into the body cavity or the inspection object, and displays the three-dimensional shape of the insertion portion on the display portion. The present invention relates to an endoscope system that can be used and an endoscope insertion portion shape detection method used therefor.

  Conventionally, endoscopes have been widely used as medical tools. The endoscope can perform various therapeutic treatments by observing organs in the body cavity by inserting an elongated insertion portion into the body cavity or using a treatment tool inserted into the treatment tool channel as necessary. Also in the industrial field, endoscopes can observe and inspect internal scratches and corrosion of boilers, turbines, engines, chemical plants, etc. by inserting elongated insertion portions.

  Such an endoscope includes a bendable bending portion on the distal end side of the insertion portion. In the endoscope, the bending portion is bent up and down or left and right by operating the bending operation knob. When the endoscope is inserted into a complicated body cavity duct, for example, a lumen that draws a loop of 360 °, such as the large intestine, the bending portion is bent by the operation of the bending operation knob and twisted. The operation is performed, and the insertion portion is inserted toward the observation target site.

  However, the endoscope operation requires skill until it becomes possible to smoothly insert the insertion portion in a short time up to the complicated deep part of the large intestine. For an inexperienced operator, when inserting the insertion portion deep into the large intestine, there is a risk of losing sight of the insertion direction, or drastically changing the running state of the intestine.

  For this reason, various proposals have conventionally been made to improve the insertability of the insertion portion. For example, Patent Document 1 discloses a device that can three-dimensionally grasp the shape of the insertion portion when inserted into a body cavity.

  In the apparatus described in Patent Document 1, two optical fibers are used as a pair, end faces of these two optical fibers are cut obliquely, and connected so as to have a predetermined opening angle with each other. The bending state is also detected by calculating the opening angle of the end face of the optical fiber.

  However, in the apparatus described in Patent Document 1, when a pair of bonded optical fibers is used, four optical fibers are required to detect bending at a certain cross-sectional position in the insertion portion, and the length is long. Four pairs of optical fibers must be arranged in each direction with different positions of the joints. Therefore, if it is intended to increase the distance resolution function in the length direction of the insertion portion, that is, when the cross-sectional position of the detection location is increased, a very large number of optical fiber pairs must be provided.

  Therefore, in view of such problems, Patent Document 2 discloses a three-dimensional shape detection device for a long flexible member that can detect the three-dimensional shape of the long flexible member with a simple and compact configuration. ing.

  In the three-dimensional detection apparatus described in Patent Document 2, two pairs of fiber Bragg gratings are provided on a sensor cable, and signal light is transmitted to the fiber Bragg grating of the sensor cable by a light source unit. When emitted, the signal processing unit receives the reflected diffraction light from each fiber Bragg grating, and compares the wavelength of this reflected diffraction light with the wavelength of the reference reflected diffraction light to determine the fiber Bragg wavelength. By measuring the distortion of the grating, the three-dimensional shape of the long flexible member is detected.

Further, as a related technique in which a fiber Bragg grating is provided in an optical fiber, for example, as shown in Patent Document 3, at least one fiber Bragg grating is provided in an optical fiber, the optical fiber is inserted into a catheter, and the fiber A technique related to an optical fiber navigation system in which a bending angle of a catheter is derived from a change in physical properties of the Bragg grating is disclosed.
JP-A-5-91972 Japanese Patent Application Laid-Open No. 2004-251779 Special table 2003-515104 gazette

  However, the conventional three-dimensional device described in Patent Document 2 includes means for detecting a three-dimensional shape such as a curved shape of an insertion portion which is a long flexible member using a fiber Bragg grating. However, in order to detect the reflected light of the fiber Bragg grating, an optical coupler such as a beam splitter or a spectroscope for separating the incident light from the light source unit and the reflected light is required.

  For this reason, this optical coupler is expensive, and since it is a highly accurate optical member, its positioning adjustment is difficult. Therefore, since such an expensive optical coupler or spectroscope is used, the cost of the entire apparatus becomes high, the apparatus becomes large, and the assembly of the apparatus is difficult. was there.

  Further, in the system described in Patent Document 3, at least one fiber Bragg grating is provided in the optical fiber. However, this optical fiber is provided in the catheter to the last, and a configuration for solving the above problems. There is no disclosure or suggestion about the elements.

  Therefore, the present invention has been made in view of the above circumstances, and it is possible to obtain distortion information from the fiber Bragg grating without using an optical coupler and to detect the three-dimensional shape of the insertion portion at a low cost and downsizing. It is an object of the present invention to provide an endoscope system capable of being assembled and excellent in assemblability and an endoscope insertion portion shape detection method used therefor.

  An endoscope system according to the present invention includes an insertion portion that is inserted into a space to be examined, a fiber Bragg grating that is inserted into the insertion portion and has a plurality of Bragg grating portions, and is incident on one end of the fiber Bragg grating A light source unit for entering light, and a detection for transmitting the incident light transmitted through the fiber Bragg grating, passing through the Bragg grating unit, being emitted as transmitted light from the other end of the fiber Bragg grating, and receiving the transmitted light And a control unit for obtaining black wavelength defect information in the transmitted light and a shift amount of the black wavelength, and detecting a distortion amount of the fiber Bragg grating.

  In addition, an endoscope insertion portion shape detection method used in the endoscope system of the present invention includes a plurality of Bragg grating portions and is attached to one end of a fiber Bragg grating inserted into an insertion portion that is inserted into a space to be inspected. The incident light is incident on the light source unit, and the incident light is transmitted through the fiber Bragg grating, passes through the Bragg grating unit, and is emitted as transmitted light from the other end of the fiber Bragg grating. And a procedure for detecting black wavelength defect information in the transmitted light and a deviation amount of the black wavelength, and detecting a distortion amount of the fiber Bragg grating by the control unit. It is characterized by.

  According to the present invention, it is possible to obtain distortion information from a fiber Bragg grating without using an optical coupler and detect a three-dimensional shape of an insertion portion. A system and an endoscope insertion portion shape detection method used therefor can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

(Example)
1 to 9 relate to an embodiment of an endoscope system of the present invention, and FIG. 1 is a system configuration diagram showing a configuration of the entire endoscope system of this embodiment.

As shown in FIG. 1, the endoscope system 1 according to the present embodiment includes an imaging means (for example, CCD 18, see FIG. 2) in the distal end portion 9 of the insertion portion 5. 5 is an electronic endoscope (hereinafter simply referred to as an endoscope) 2 provided with a drive unit (specifically, a motor) 14 for bending the bending portion 10, and is detachably connected to the endoscope 2. A light source device 23 that supplies incident light to the endoscope 2 and a signal processing unit that controls an imaging unit of the endoscope 2 and processes a signal obtained from the imaging unit to output a standard video signal And a monitor 4 for displaying an image such as an endoscopic image based on a video signal obtained by signal processing by a signal processing unit of the control device 3.
The control device 3 may be provided with a connector portion that can electrically connect a printer, a video disk, an image recording device, or the like (not shown).

  The endoscope 2 includes an elongated insertion portion 5 to be inserted into a site to be observed, an operation portion 6 which is connected to a proximal end portion of the insertion portion 5 and has an operation knob 13 such as a video switch or a bending operation switch, A universal cord 7 extending from the side surface of the operation unit 6 and incorporating a signal cable connected to the imaging means, an optical fiber 12 to be described later, and the like, and provided at the end of the universal cord 7, is attached to and detached from the control device 3. And a connector portion 8 that is freely connected.

The insertion portion 5 is provided with a distal end portion 9 provided on the distal end side, a bendable bending portion 10 provided on the proximal side of the distal end portion 9, and a proximal side of the bending portion 10. A long and flexible flexible tube portion 11 formed of a member is provided in series.
Moreover, although it mentions later, the optical fiber 12 which comprises a fiber Bragg grating is penetrated in the insertion part 5. As shown in FIG.

  The distal end portion 9 has an image sensor such as a CCD (Charge Coupled Device) 18 or an image sensor such as a CMOS (Complementary Metal Oxide Semiconductor) as an imaging means.

  Further, the tip 9 is an imaging unit in which a circuit board for driving the CCD 18 is incorporated, an LED 18A for irradiating illumination light for illuminating an observation target site such as a body cavity, and the LED drive line of the LED 18A. 39 etc. are built in.

  The bending portion 10 is bent when the motor 14 as the driving portion is driven by the operation of the operation knob 13 of the operation portion 6. Note that the bending operation of the bending portion 10 may be bent by a manual operation without using the electric drive means such as the motor 14.

  The operation knob 13 is composed of, for example, a joystick. The operation knob 13 is electrically connected to a controller (not shown) in the control device 3 via a signal line (not shown), and an operation for bending the bending portion 10 by operating the operation knob 13. The signal is output to a controller (not shown). A controller (not shown) controls the motor 14 based on the supplied operation signal, so that the bending portion 10 is bent in a desired direction.

A connector portion 8 of the universal cord 7 of the endoscope 2 is detachably connected to a connector portion 16 provided in the control device 3.
The connector unit 8 includes a connector 8a for electrically connecting the drive signal lines 21 and 22 and the LED drive line 39 (see FIG. 2) electrically connected to the CCD 18 to the control device 3, and an internal view described later. An optical connector 8b for optically connecting the optical fiber 12 inserted into the insertion portion 5 of the mirror 2 and the universal cord 7 to the control device 3 is provided.

  In contrast, the connector unit 16 of the control device 3 includes a connector 16a for electrically connecting the connector 8a and a corresponding signal processing unit in the control device 3, and the optical connector 8b and the control device 3 in the control device 3. The optical connector 16b for optically connecting the light source device 23 and the detection unit 26 described later.

  A monitor 4 such as an LCD is provided above the control device 3. The monitor 4 includes, for example, an endoscopic image 4B based on a video signal (Video signal) captured by the CCD 18 and processed by a signal processing unit of the control device 3, and a fiber Bragg of an optical fiber 12 to be described later. The curved shape image 4C of the insertion unit 5 based on the shape CG signal detected by the grating and processed by the signal processing unit of the control device 3 is combined with the left and right and displayed on the screen 4A.

  Accordingly, the surgeon can perform observation and treatment while viewing the endoscope image 4B, and smoothly perform the forward / backward operation of the insertion portion 5 by viewing the curved shape image 4C of the insertion portion 5. be able to. The monitor 4 can selectively display any data during the operation.

  The operation panel 19 on the front side of the control device 3 is provided with operation switches 19 such as a power button, a monitor switch, and a power button of the light source device 23, for example.

Next, the configuration of the main part, which is a feature of the endoscope system 1 of the present embodiment, will be described with reference to FIGS.
FIG. 2 is a block diagram showing the electrical configuration of the entire system including the main part of the endoscope system of the present embodiment.
As shown in FIG. 2, a plurality of fiber Bragg gratings (hereinafter referred to as FBG sensors) λ1, λ2, λ3,... Λn (inside the insertion portion 5 and the universal cord 7 of the endoscope 2) The optical fiber 12 in which n is an integer) is inserted.

Further, inside the insertion portion 5 and the universal cord 7 of the endoscope 2, drive signal lines 21 and 22 from the drive buffer 19 </ b> A and the imaging signal buffer 20 connected to the input / output terminals of the CCD 18 in the distal end portion 9, respectively. The LED drive line 39 from the LED 18A in the distal end portion 9 is inserted.
A cover lens 17 that covers the imaging range of the CCD 18 and an illumination lens 18a that emits LED illumination light from the LED 18A are provided on the distal end surface of the distal end portion 9.

  Each of the FBG sensors λ1, λ2, λ3,... Λn of the optical fiber 12 obtains reflected light and transmitted light of the incident light by changing the wavelength of the incident light, and also includes a Bragg grating portion 42 (see FIG. 4). The configuration of the optical fiber 12 and the detection principle by the FBG sensor will be described later.

  Incident light 40 is incident on an incident end (specifically, optical connector 8 b) of the optical fiber 12 by a light source device 23 in the control device 3 to be described later, and is linearly arranged on the optical fiber 12. Each of the FBG sensors λ1, λ2, λ3,.

The light transmitted through each of the FBG sensors λ1, λ2, λ3,... Λn reaches the detection unit 26 in the control device 3 through the optical connector 8b as transmitted light 41.
For example, when distortion stress occurs due to the bending of the insertion portion 5, each of the FBG sensors λ 1, λ 2, λ 3,... Λn has a characteristic of converting the amount of distortion into each wavelength missing shift of the transmitted light 41. Yes. Then, transmitted light 41 having this wavelength missing information (also referred to as Bragg wavelength missing information) is supplied to the detection unit 26 in the control device 3, and the wavelength missing information is detected by this detection unit 26.
In addition, the specific structure of the control apparatus 3 which comprises a control part is mentioned later.

Here, a specific configuration of the optical fiber 12 and a detection principle by the FBG sensor λ for performing the endoscope insertion portion shape detection method will be described with reference to FIGS. 3 to 8.
3 is a partially broken perspective view showing the configuration of the insertion portion disposed through the optical fiber, and FIGS. 4 to 6 illustrate the configuration and principle of the optical fiber and the FBG sensor. Is an explanatory diagram for explaining the configuration and principle of an optical fiber having an FBG sensor, FIG. 5 is a spectral distribution graph showing the light intensity-wavelength characteristics of incident light supplied to the optical fiber, and FIG. 6 is an output from the optical fiber. FIG. 7 and FIG. 8 explain the state of the spectral shift of the transmitted light through the optical fiber and the determination of the shift amount from the change. FIG. FIG. 8 is a characteristic diagram for explaining a method of determining a missing wavelength by detecting a shift amount of a transmission spectrum, and FIG. 8 is a spectrum distribution graph of light intensity-wavelength characteristics showing spectral shift of light.

  As shown in FIG. 3, the optical fiber 12 is inserted from the proximal side of the insertion portion 5 to the distal end side of the insertion portion 5 and inserted to the proximal side of the insertion portion 5.

Each of the FBG sensors λ 1, λ 2, λ 3,. It arrange | positions for every predetermined space | interval in the longitudinal direction to a boundary part, or the longitudinal direction from the said boundary part to the hand side of the insertion part 5. FIG.
That is, the single optical fiber 12 includes an incident light side portion from the proximal side of the insertion portion 5 to the boundary portion, and a transmitted light side portion from the boundary portion to the proximal side of the insertion portion 5. . Each of the FBG sensors λ1, λ2, λ3,... Λn may be provided on at least one of the incident light side portion and the transmission hole side portion of the optical fiber 12.

  In this embodiment, as shown in FIG. 3, two optical fibers 12 are provided for detecting the UP direction of the insertion portion 5 and for detecting the DOWN direction of the insertion portion 5, respectively. These optical fibers 12 are arranged so as to face each other in the vertical direction in the insertion portion 5.

  In this case, the optical fiber 12 for the UP direction is provided with a plurality of FBG sensors λ1, λ2, λ3,... Λn having the Bragg grating portion 42, and the Bragg grating 43 is provided for the optical fiber 12 for the DOWN direction. A plurality of FBG sensors λ1, λ2, λ3,... Λn are provided.

  The UP-direction optical fiber 12 receives the UP incident light 40a from the hand side, and supplies the UP transmitted light 41a to the control device 3 through the incident light side portion and the transmitted light side portion. At the same time, the DOWN direction optical fiber 12 receives the DOWN incident light 40b from the hand side, and supplies the DOWN transmitted light 41b to the control device 3 via the incident light side portion and the transmitted light side portion. It has become.

  The folded portion on the distal end side of the insertion portion 5 of the optical fiber 12 is preferably disposed at the boundary portion between the distal end portion 9 and the bending portion 10, but is not limited to this.

  Further, in the present embodiment, as shown in FIG. 3, the two detection directions of the UP direction and the DOWN direction of the insertion unit 5 have been described. However, the present invention is not limited to this. When detecting in four directions, DOWN, LEFT, and REGHT, four optical fibers 12 (fiber Bragg gratings) may be arranged in the vertical and horizontal directions in the insertion portion 5.

A specific configuration of such an optical fiber 12 is shown in FIG.
As shown in FIG. 4, the optical fiber 12 includes a clad portion 12B and a core portion 12A arranged inside the clad portion 12B. The FBG sensor λ provided in the optical fiber 12 forms a Bragg grating portion 42 by periodically changing the refractive index in the axial direction in the core portion 12A through which the light of the single mode optical fiber propagates. .
Note that the lattice interval of the Bragg grating portion 42 is, for example, about 0.4 to 0.5 microns, and the sensor length is configured to be about several mm to several tens of mm.
In the present embodiment, the plurality of Bragg grating portions 42 may be arranged so as to gradually become denser from the proximal end side to the distal end side of the optical fiber 12 constituting the fiber Bragg grating. This makes it possible to detect the distortion amount of the FBG sensor λ with higher accuracy.

When the incident light 40 is incident on the FBG sensor λ, the Bragg grating portion 42 reflects only the Bragg wavelength component having a specific peak wavelength corresponding to the FBG grating interval and the refractive index (transmittance) at the FBG sensor λ.
Here, for example, when the FBG sensor λ is distorted (distorted), as shown in FIG. 4, light having a wavelength component shifted by Δλm with respect to the black wavelength reflected without distortion. 40x is reflected light.
As a result, the transmitted light 41 of the optical fiber 12 is transmitted as information in which only the Bragg wavelength component of the specific peak wavelength is missing.

  Note that the FGB lattice spacing and the refractive index (transmittance) of the FGB sensor λ vary depending on the strain and temperature of the FBG sensor λ. Therefore, when the strain information (strain amount) is detected with high accuracy using the FBG sensor λ, it is necessary to separate the temperature shift information.

  Therefore, in the endoscope system 1 of the present embodiment, when detecting strain information (amount of strain) using the FBG sensor λ, high-precision detection processing is performed by separating temperature shift information. Is possible.

  Specifically, the temperature (including the position) of the plurality of FBG sensors λ1, λ2, λ3,... Λn provided in the optical fiber 12 is detected using the temperature detection function that the optical fiber 12 originally has, Then, a temperature change amount due to a temperature change is obtained from the detection result, and a distortion amount applied to each Bragg grating portion 42 of the detected FBG sensors λ1, λ2, λ3,... Λn is corrected based on the temperature change amount. Thus, it is possible to detect the curved shape of the insertion portion 5 with high accuracy.

  In addition, without using the original temperature detection function of the optical fiber 12, for example, in the transmitted light side portion of the optical fiber 12 (the portion from the boundary portion between the distal end portion 9 and the bending portion 10 to the proximal side of the insertion portion 5), A plurality of temperature sensors for detecting the respective temperatures may be provided at corresponding positions of the FBG sensors λ1, λ2, λ3,.

  As described above, such an FGB sensor λ can detect the amount of mechanical distortion as a wavelength shift of light, and can perform wavelength multiplexing. Therefore, if the FBG sensors λ1, λ2, λ3,... Λn corresponding to a plurality of different specific peak wavelengths are arranged on the same optical fiber 12, distortion at a plurality of parts in the transmission path of one optical fiber 12 Information (distortion amount) can be detected as a shift of a specific wavelength.

Incident light having a spectral distribution as shown in FIG. 5 is supplied to the optical fiber 12 through the light source device 23 in the control device 3. In order to emit such incident light, for example, a broadband light source having ASE (Amplified Spontaneous Emission) characteristics is used, or discretely corresponding to the Bragg wavelength component of the Bragg grating portion 42 of the FBG sensor λ. It is also possible to use an oscillator that oscillates and operates a narrow-band laser beam.
The incident light preferably covers the strain response frequency (wavelength) of the FGB sensor λ provided in the optical fiber 12 and has high stability.

In this embodiment, the transmitted light that passes through the optical fiber 12 is transmitted as information in which only the Bragg wavelength component of the specific peak wavelength is missing in the Bragg grating portion 42 of the FBG sensor λ. In addition, the Bragg lattice spacing will change.
In such a case, as shown in FIG. 6, the transmitted light has a Bragg wavelength component with a specific peak wavelength shifted by Δλm.

  FIG. 7 shows a spectrum distribution graph of the light intensity-wavelength characteristic indicating the spectral shift of the transmitted light, explaining the state of the spectral shift of the transmitted light through the optical fiber and the determination of the shift amount from the change. Yes.

  In this embodiment, when the FBG sensor λ is not distorted, the transmitted light of the optical fiber 12 has a spectrum distribution that is missing at the specific peak wavelength λm portion as shown in FIG. That is, the transmitted light has a Bragg wavelength component 100 having a specific peak wavelength.

  On the other hand, when distortion occurs in the FBG sensor λ, the transmitted light of the optical fiber 12 has a Bragg wavelength component in which the Bragg wavelength component 100 of the specific peak wavelength is shifted by Δλm as shown in FIG. 101 is provided. For example, the Bragg wavelength component 101 is wavelength-shifted in a wavelength shift region of λm ± Δλm, and is a portion where the wavelength is missing.

  In this embodiment, the amount of deviation of the transmitted light spectrum is detected from the transmitted light from such an optical fiber 12 to determine missing information. FIG. 8 is a characteristic diagram for explaining a method for determining such missing information.

  In order to detect the distortion amount of the FBG sensor λ with high accuracy, it is necessary to accurately detect a portion where the specific peak wavelength is missing from the transmitted light from the optical fiber 12. That is, it is necessary to measure and determine the wavelength in consideration of the fact that the missing wavelength portion in the transmitted light has a finite spectral bandwidth.

  Therefore, in this embodiment, for example, a determination method for detecting a specific missing peak value and a missing wavelength width of transmitted light using a half-value wavelength concept as shown in FIG. 8 is performed.

For example, in FIG. 8, when the minimum wavelength 97 of the missing wavelength portion is Δλmin, the maximum wavelength 98 of the missing wavelength portion is Δλmax, and the half-value wavelength width 99 of the missing wavelength portion is w,
The minimum wavelength Δλmin of the missing wavelength portion is defined by taking the half value of the defect envelope 104, and similarly, the maximum wavelength Δλmax of the missing wavelength portion is defined by taking the half value of the defect envelope 104.

In this case, the half-value wavelength width w of the missing wavelength portion is
w = Δλmin−Δλmax (Formula 1)
Defined as
The center wavelength 102 of the defect envelope 104 is
λcent = (Δλmax + Δλmin) / 2 (Expression 2)
Define as

In this embodiment, the shift determination of a specific wavelength is performed by using at least one of the center wavelength λcent, the half-value wavelength width w, the minimum wavelength Δλmin, and the maximum wavelength Δmax, or a combination thereof.
Further, as a method for detecting the shift of the specific wavelength, a method of calculating a predicted intersection or approximate curve of the defect envelope 104 and estimating the specific wavelength peak based on the calculation result may be used.
This makes it possible to accurately detect a portion where the specific peak wavelength 103 is missing from the transmitted light from the optical fiber 12 with high accuracy.
Such shift determination of a specific wavelength is performed by the detection unit 26 described later.

Next, returning to FIG. 1, a specific configuration of the control device 3 having the detection unit 26 and an endoscope insertion portion shape detection method controlled by the control device 3 will be described.
As illustrated in FIG. 1, the control device 3 includes a light source device 23, a light source element 24, a light source control unit 25, a signal processing unit, a detection unit 26, a CPU 27 that controls the entire control device 3, and video processing. A unit 27A, a camera control unit (hereinafter referred to as CCU) 28, and a superimposing unit 35.

  As described above, the incident light 40 is incident on the incident side (specifically, the optical connector 8 b) of the optical fiber 12 by the light source device 23 in the control device 3, and the optical fiber 12 is linearly incident on the optical fiber 12. Are transmitted through the FBG sensors λ1, λ2, λ3,.

  And the light which permeate | transmitted each FBG sensor (lambda) 1, (lambda) 2, (lambda) 3 ... (lambda) n reaches | attains the detection part 26 in the control apparatus 3 via the optical connector 8b as the transmitted light 41. FIG.

  For example, when distortion stress occurs due to the bending of the insertion portion 5, each FBG sensor λ1, λ2, λ3,... Λn converts the distortion amount into each missing wavelength displacement of the transmitted light 41 as described above. The transmitted light 41 having this wavelength loss information is supplied to the detection unit 26 in the control device 3.

  And the detection part 26 will detect the wavelength missing information of transmitted light using the above-mentioned methods.

  The light source device 23 supplies incident light to the optical fiber 12 using a light source element 24 such as a lamp, LED, or laser, and is a light source that generates a broadband spectrum or a light source unit that scans a narrow band laser.

  For example, the light source device 23 is capable of high light output of total light output +13 dBm and light spectrum density -13 dBm / nm (wavelength range: 1530 nm to 1605 nm) in the C + L band, and total light output +6 dBm and light spectrum density -25 dBm in the S band. / Nm or higher (wavelength range: 1450 nm to 1510 nm) is desirable. Note that the light source device 23 is not limited to the light source device 23 as long as it can always supply the stable incident light 40 to the optical fiber 12.

  The light source control unit 25 performs control so that the light source wavelength (frequency) of the light source device 23 is always stabilized. Specifically, the light source control unit 25 controls the light source device 23 by supplying a control signal 30 that sets the light source wavelength (frequency) of the light source device 23 to f ± Δf.

  Further, the detection unit 26 detects specific wavelength missing information (black wavelength defect information) from the transmitted light from the optical fiber 12 as described above, and uses the specific wavelength missing information (frequency) as the fded signal 31 to be a light source control unit. 25, and the specific wavelength missing information (frequency) is output to the CPU 27 as an Fded detection signal 32.

  The light source control unit 25 controls the light source device 23 based on the supplied fded signal 31. In this case, the CPU 27 supplies a control signal such as the Fref setting signal 34 to the light source control unit 25 to set the wavelength (frequency) of the incident light, and the specific wavelength missing information (Fded signal 31) from the detection unit 26. , And the amount of distortion generated in each FBG sensor λ1, λ2, λ3,.

  That is, the CPU 27 obtains the specific frequency defect wavelength (black wavelength defect information) and the black wavelength shift amount of the Bragg grating part 42 of each FBG sensor λ using the transmitted light received by the detection part 26, and obtains this finding. Further, based on the specific frequency defect wavelength (black wavelength defect information) of each black grating part 42 and the shift amount of the black wavelength, an arithmetic processing is performed so as to detect the distortion amount applied to each Bragg grating part 42 in the optical fiber 12. Do.

  Further, the CPU 27 calculates three-dimensional shape information generated in the insertion portion 5 or the bending portion 10 from the distortion amount of each Bragg grating portion 42 of each FBG sensor λ1, λ2, λ3,. The video is output to the video processing unit 27A.

  Based on the supplied shape information CG signal, the video processing unit 27A converts the three-dimensional shape of the insertion unit 5 into a shape CG signal 37 which is a video signal for displaying on the monitor 4, and is supplied to the superimposing unit 35. The

  On the other hand, the superimposing unit 35 is supplied with a video signal (Video signal) 36 in which an image signal processed by the CCD 18 is processed by the CCU 28.

  The superimposing unit 35 is, for example, a multiplier, and superimposes the shape CG signal 37 on the supplied video signal (Video signal) 36 to generate a composite video signal (CG / Video signal) 38 and output it to the monitor 4.

  Thus, on the screen 4 A of the monitor 4, a composite video based on the composite video signal (CG / Video signal), that is, an endoscopic image 4 B based on the video signal (Video signal) 36 and an insertion unit based on the shape CG signal 37. A composite image in which the curved shape image 4C of 5 is combined on the left and right is displayed.

A display example of the screen 4A of the monitor 4 at this time is shown in FIG.
For example, as shown in FIG. 9, an endoscope image 4B is displayed on the left side of the screen 4A of the monitor 4, and a curved image 4C is displayed on the right side of the screen 4A.
In this case, the endoscopic image 4B is a live image of a normal subject, but the curved shape image 4C has, for example, a three-dimensional shape corresponding to the x, y, and z directions of the inserted portion 5 in the subject. In this three-dimensional shape, the position of the distal end portion 9 of the insertion portion 5 in the subject, and the positions of the respective FBG sensors λ1, λ2, λ3,... Λn provided in the optical fiber 12 in the insertion portion 5 in the three-dimensional shape A tertiary display displaying a marker display unit 45 for instructing a direction indication in the vertical and horizontal directions with respect to the tip portion 9 of the three-dimensional shape, and three-dimensional coordinate data indicating the positions of the FBG sensors λ1, λ2, λ3,. The original coordinate data display unit 46 is displayed.

  Thus, the surgeon can perform observation and treatment while viewing the endoscope image 4B. In addition, the operator can view the curved shape image 4C of the insertion portion 5 in any state. Since it is possible to recognize at a glance whether the insertion part 5 is arranged in the subject, it is possible to specify the examination site and to smoothly move the insertion part 5 back and forth.

  Therefore, according to the present embodiment, distortion information from the fiber Bragg grating can be obtained without using the expensive optical coupler used in the prior art, and the three-dimensional shape and the curved shape of the insertion portion 5 can be detected. An inexpensive endoscope system capable of detecting the three-dimensional shape of the insertion portion 5 and an endoscope insertion portion shape detection method used therefor can be provided.

  In addition, since an expensive optical coupler is not used, it is possible to obtain an effect of reducing the size and assembling of the endoscope system.

  Further, since the endoscope image 4B and the curved shape image 4C can be displayed on the monitor 4 in, for example, two screens, the operator can perform observation and treatment while viewing the endoscope image 4B. By looking at the curved shape image 4C of the insertion portion 5, it is possible to recognize at a glance in what state the insertion portion 5 of the endoscope 2 is arranged in the subject. The identification and the advance / retreat operation of the insertion portion 5 can be performed smoothly. Therefore, it greatly contributes to improving the operability of the endoscope 2.

  In this embodiment, the case where the endoscope image 4B and the two-screen display are displayed on the screen 4A of the monitor 4 as a display example of the curved shape image 4C has been described. However, the present invention is not limited to this and is necessary. The display may be switched as appropriate according to the situation.

Further, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

The system block diagram which shows the structure of the whole endoscope system of one Example of the endoscope system of this invention. The block diagram which shows the electrical structure of the whole system containing the principal part of the endoscope system of a present Example. The perspective view which fractured | ruptured partially which shows the structure of the insertion part arrange | positioned by inserting an optical fiber inside. Explanatory drawing for demonstrating the structure and principle of an optical fiber which has a FBG sensor. The spectrum distribution graph which shows the light intensity-wavelength characteristic of the incident light supplied to an optical fiber. The spectrum distribution graph which shows the light intensity-wavelength characteristic of the transmitted light which an optical fiber outputs. The spectral distribution graph of the light intensity-wavelength characteristic showing the spectral shift of transmitted light. The characteristic view for demonstrating the method of detecting the deviation | shift amount of a transmission spectrum and determining a missing wavelength. The figure which shows the example of a screen display of a monitor at the time of displaying an endoscopic image and a curved shape image on 2 screens.

Explanation of symbols

1 ... endoscope system,
2. Endoscope,
3 ... Control device,
4 ... Monitor,
4A ... screen,
4B ... Endoscopic image,
4C ... curved shape image,
5 ... Insertion part,
6 ... operation part,
7 ... Universal code,
8 ... Connector part,
8a ... Connector,
8b: optical connector,
9 ... the tip,
10: curved part,
11 ... Flexible tube part,
12A ... Core part,
12B ... clad part,
12C ... Bragg lattice part,
12: optical fiber,
13 ... Control knob,
14 ... motor,
16a ... Connector,
16 ... Connector part,
16b: optical connector,
19: Operation switch,
23 ... Light source device,
24. Light source element,
25 ... Light source control unit,
26: detection unit,
27A ... Video processing unit,
33 ... Light source control unit,
35 ... Superimposition part,
40: Incident light,
41 ... transmitted light,
42, 43 ... Bragg lattice part,
100: Bragg wavelength component,
102 ... Center wavelength,
103 ... specific peak wavelength,
104 ... Defect envelope,
w: Half-value wavelength width,
Δmax: maximum wavelength,
Δλmax: Maximum wavelength,
Δλmin: minimum wavelength,
λ ... FBG sensor,
λcent ... center wavelength,
λm: Specific peak wavelength.

Claims (10)

An insertion portion to be inserted into the inspection target space;
A fiber Bragg grating inserted into the insertion portion and formed with a plurality of Bragg grating portions;
A light source unit that makes incident light incident on one end of the fiber Bragg grating;
The incident light is transmitted in the fiber Bragg grating and transmitted through the Bragg grating part, and is emitted as transmitted light from the other end of the fiber Bragg grating, and a detection part that receives the transmitted light;
The black wavelength defect information in the transmitted light and the amount of deviation of the black wavelength are obtained, and a control unit that detects the distortion amount of the fiber Bragg grating,
An endoscope system comprising:   The at least one fiber Bragg grating is inserted from a proximal end side in the insertion portion to a distal end side in the insertion portion, and is further folded back at the distal end side and inserted to the proximal end side. The endoscope system according to Item 1.   The endoscope system according to claim 2, wherein a portion where the fiber Bragg grating is folded is disposed at a boundary between a distal end portion and a bending portion of the insertion portion.   The plurality of Bragg grating portions are arranged so as to gradually become denser from the proximal end side to the distal end side of the fiber Bragg grating. Endoscope system according to one. The light source unit is
The endoscope system according to claim 1, wherein the endoscope system scans a light source that generates a broadband spectrum or a narrow-band laser.   The detection of the Bragg wavelength defect information by the control unit is performed using a half value of the light intensity of the defect spectrum of the transmitted light. Endoscopic system. A signal processing unit for generating a three-dimensional shape of the insertion unit based on a strain amount of the fiber Bragg grating;
A display unit that displays an observation image observed by the insertion unit;
The endoscope apparatus according to any one of claims 1 to 6, wherein the control unit controls the observation image and the three-dimensional shape to be displayed on two screens.   The endoscope system according to claim 7, wherein the control unit controls the display unit to further display a marker indicating a vertical direction with respect to a distal end portion of the insertion unit. A main body that accommodates the control unit, the signal processing unit, the detection unit, and the light source unit therein, and is extended from the proximal side of the insertion unit, and the fiber Bragg grating and the signal line in the insertion unit are inserted therein. It has a connector part that detachably connects to the universal cord,
The connector part is detachable from the light source part, the detection part, and the fiber Bragg grating so that the incident light can be incident on the fiber Bragg grating and at the same time, the transmitted light from the fiber Bragg grating can be received. The endoscope system according to any one of claims 1 to 8, further comprising a connectable optical connector portion. A procedure including incident light by a light source unit at one end of a fiber Bragg grating including a plurality of Bragg grating units and inserted into an insertion unit that is inserted into a space to be inspected;
The incident light is transmitted in the fiber Bragg grating and passes through the Bragg grating part, and is emitted as transmitted light from the other end of the fiber Bragg grating, and the transmitted light is received by the detection part,
Obtaining black wavelength defect information in the transmitted light and the amount of deviation of the black wavelength, and detecting the amount of distortion of the fiber Bragg grating by the control unit;
An endoscope insertion portion shape detection method for use in an endoscope system, comprising:

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