JP2011255015A - Endoscopic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct the light quantity of illumination light without using a calibration tool in an endoscopic apparatus.SOLUTION: The endoscopic apparatus includes: a light source which emits the light having a specified wavelength band zone; an emission optical fiber which is combined with the light from the light source through a light combining means, and spreads the light; a scanning means which makes the light spread by the emission optical fiber scan in an objective area; a light receiving element which receives leaked light from the emission optical fiber; and a light quantity correcting means which corrects the emission light quantity of the light source conforming to the received light quantity of the light receiving element.

Description

  The present invention relates to an endoscope apparatus, and more particularly, to an apparatus that corrects the amount of illumination light used for imaging an endoscope by controlling a light source.

  An endoscope is generally known as an apparatus used when a doctor observes a body cavity of a patient. A doctor who uses the endoscope inserts the insertion portion of the endoscope into the body cavity and guides the distal end portion of the insertion portion to the vicinity of the site to be observed. And the image in a body cavity is imaged with the image pick-up element incorporated in the front-end | tip part. The image signal imaged in the body cavity is transmitted from the endoscope to the video processor. The video processor performs predetermined processing on the received image signal and displays an image in the body cavity on the monitor. The doctor observes the image in the body cavity displayed on the monitor and performs examinations and treatments.

  Conventional general endoscopes use an image sensor for acquiring an observation image, such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). A next-generation imaging system disclosed in Document 1 has been proposed. In this imaging system, an observation target region is scanned using a scanning optical fiber and laser light, and color information for each dot of the observation target region is obtained and imaged.

  Patent Document 1 discloses a distal end portion of an endoscope insertion portion in a conventional scanning endoscope using such an imaging system. A scanning optical fiber is inserted through a cylindrical piezoelectric element. The piezoelectric element is provided with an electrode, and the piezoelectric element is driven by the electrode. The piezoelectric element is fixed in the sheath of the insertion portion by a fixing material, and is joined to the scanning optical fiber by an adhesive.

  The piezoelectric element resonates the tip of the optical fiber, whereby the tip of the optical fiber is scanned spirally, and this spiral scanning is repeated at a predetermined cycle. The light emitted from the optical fiber at this predetermined period is condensed on the observation target by the optical lens, scanned on the observation target with the above scanning pattern, and the reflected light from the observation target is transmitted through the optical fiber. It propagates through a plurality of light receiving optical fibers arranged in an annular shape as the center and reaches a light receiving portion in the video processor. The technical principle that a spiral scan of the tip of the scanning optical fiber is repeatedly executed at a predetermined cycle, whereby a full-color image is displayed on the monitor is described in Patent Document 2 and Non-Patent Document 1. Are described in technical literature.

US Pat. No. 6,563,105 US Pat. No. 6,856,712

SPIE Bulletin, Optical Engineering, February 2006, Volume 6083, Sebel et al. “A full-color scanning fiber endoscope” Proceeding of SPIE, Vol. 6083, Optical Engineering, February, 2006

  In the conventional scanning endoscope system described above, an optical fiber for propagating the laser light emitted from the light source in the video processor and an emitted light for guiding the laser light to the distal end of the insertion portion in the endoscope. The fiber is connected using an optical connector provided in the endoscope and the video processor as optical coupling means. Then, in order to prevent the amount of laser light emitted from the distal end of the insertion portion from exceeding a predetermined amount, the light source is emitted by a calibration jig provided on the video processor side that can insert the distal end of the insertion portion. It is necessary to initialize the amount of light. Since the calibration jig is often non-sterile, a sterilized endoscope must be brought into contact with the non-sterile jig at the site where the medical device is handled. This raises concerns about hygiene management during calibration. Also, when connecting the endoscope and the calibration jig separately using a mediation jig, there are new problems such as the manufacturing cost of the mediation jig and the labor involved in installing and removing the mediation jig during calibration. It can happen. In addition, if the surgeon starts the procedure without performing calibration work, the illumination light is emitted with a light quantity that is regarded as a dangerous area at the start of the procedure, or the illumination light does not reach the desired light quantity, causing a hindrance to the procedure. there's a possibility that.

  In addition, repeated connection between the endoscope and the video processor results in light loss due to deterioration of the end face of the optical connector connection, scratches on the end face, dust adhering to the end face, misalignment of the end face, etc. appear. If the light loss at the optical connector is large, the light quantity of the illumination light is reduced, and the image quality of the captured image of the endoscope may be reduced. Further, when the laser output of the light source on the video processor side is increased in order to compensate for the loss of the light amount on the endoscope side, the amount of light emitted from the light source may become excessive.

  The present invention has been made in view of the above circumstances. It is an object of the present invention to detect a light amount loss in propagation of illumination light used for imaging of a target region, in particular, a light amount loss in an optical connector used on a propagation path of illumination light, and to correct the light amount of illumination light. A mirror device is provided.

  An endoscope apparatus according to an embodiment of the present invention includes a light source that emits light having a predetermined wavelength band, an output optical fiber that is coupled with light from the light source via an optical coupling unit, and propagates the light, Scanning means for scanning the light propagated by the outgoing optical fiber over the target portion, a light receiving element for receiving the leaked light from the outgoing optical fiber, and a light quantity correcting means for correcting the outgoing light quantity of the light source based on the amount of light received by the light receiving element And have. The endoscope apparatus further includes a received light amount comparing unit that compares the received light amount of the light receiving element with a first threshold, and the light amount correcting unit is based on a result of comparison by the received light amount comparing unit. Perform the correction.

  Preferably, the light quantity correction means corrects the emitted light quantity of the light source when the comparison result by the light reception quantity comparison means indicates that the light reception quantity of the light receiving element is different from the first threshold value, and the light reception quantity comparison means When the comparison result indicates that the amount of light received by the light receiving element is equal to the first threshold value, the amount of light emitted from the light source is not corrected.

  Further, when the received light amount of the light receiving element is different from the first threshold value, the received light amount comparing unit compares the received light amount of the light receiving element with a second threshold value smaller than the first threshold value, and the light amount correcting unit When the result of comparison by the amount comparison means indicates that the amount of light received by the light receiving element is smaller than the second threshold value, the amount of light emitted from the light source is not corrected.

  More preferably, the endoscope apparatus further includes a threshold setting unit that sets a first threshold based on an initial setting value of the emitted light amount of the light source. Therefore, by setting the emitted light quantity of the light source at the time of light quantity correction to a value smaller than the initial setting value for the treatment, the emitted light quantity from the light source can be reliably stored in a safe range and the light quantity can be corrected. It can be expected to improve safety during light amount correction. The light receiving element is arranged in the vicinity of the optical coupling means. Thereby, the light quantity loss in the optical coupling means can be detected with higher accuracy and the light quantity can be corrected. The endoscope apparatus further includes notification means for notifying that the result of comparison by the received light amount comparing means is that the received light amount of the light receiving element is smaller than the second threshold value.

  The predetermined wavelength band includes wavelengths of light of red (R), green (G), and blue (B), and the first and second threshold values are set for each of R, G, and B light. The received light amount comparing means compares the received light amount received by the light receiving element for each of R, G, B from the light source with a first threshold value for each of R, G, B light, When the received light amount of the element is different from the first threshold value, the received light amount of the light receiving element is compared with the second threshold value for each of R, G, and B light, and the light amount correcting means is set for each of R, G, and B light. In addition, when the comparison result by the received light amount comparing means indicates that the received light amount of the light receiving element is smaller than the second threshold value, the emitted light amount of the light source is corrected. The predetermined wavelength band includes a wavelength at which the light receiving sensitivity of the light receiving element is low, and at least one of the light receiving surface of the light receiving element, the vicinity of the light receiving element, and the outgoing optical fiber has a wavelength at which the light receiving sensitivity of the light receiving element is low. A fluorescent member that emits fluorescence when excited is applied. As a result, even in an endoscope apparatus in which the light source is composed of LEDs that emit R, G, and B color lights and performs visible light observation, special light observation is performed by emitting only light of a specific short wavelength from the light source. Also in the endoscope, the amount of light emitted from the light source can be suitably controlled.

  According to the endoscope apparatus of the present invention, the threshold value is set based on the amount of light received by the light receiving element at the time of factory shipment or initial connection, and the light source (the light of each wavelength when a plurality of wavelengths are used) based on the threshold value. ), The operation can be performed with the light quantity emitted from the light source set to a suitable value. Moreover, when performing a treatment using light of a plurality of wavelengths, the balance of the light amounts of the respective wavelengths can be adjusted. Furthermore, since it is not necessary to use a calibration jig, it is possible to perform light quantity correction while maintaining the sterilized state of the endoscope tip, and it is possible to save work such as jig sterilization.

FIG. 1 is a schematic diagram showing an endoscope apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing a part of the endoscope apparatus according to the first embodiment of the present invention. FIG. 3 is a schematic diagram showing a part of the endoscope apparatus according to the first embodiment of the present invention. FIG. 4 is a schematic diagram illustrating a part of the endoscope apparatus according to the first embodiment of the present invention. FIGS. 5A to 5C are graphs showing the characteristics of the light receiving elements of the endoscope apparatus according to the first embodiment of the present invention. FIGS. 6A to 6C are flowcharts of light amount correction processing by the endoscope apparatus according to the first embodiment of the present invention. FIG. 7 is a block diagram showing a part of an endoscope apparatus according to the second embodiment of the present invention. FIG. 8 is a schematic diagram showing a part of an endoscope apparatus according to the second embodiment of the present invention. FIGS. 9A to 9C are graphs showing the characteristics of the light receiving elements of the endoscope apparatus according to the second embodiment of the present invention. FIG. 10 is a schematic diagram showing a part of an endoscope apparatus according to the second embodiment of the present invention.

  Hereinafter, an endoscope apparatus according to an embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol shall be attached | subjected when showing the same member over several figures.

  FIG. 1 shows a schematic diagram of an endoscope apparatus 100 according to the first embodiment. As shown in the figure, the endoscope apparatus 100 includes a scanning endoscope 1 for imaging a target region. The endoscope 1 includes a flexible tube 6 covered with a flexible sheath. Connected to the distal end of the flexible tube 6 is a distal end portion 4 covered with a hard resin. The flexible tube 6 and the distal end portion 4 are connected by a bending portion 5. The bending portion 5 is configured to be bendable by an angle knob 8 that is rotatably provided at an operation portion 7 connected to the base end of the flexible tube 6. The bending mechanism of the bending portion 5 is a well-known mechanism incorporated in a general endoscope, and the bending portion 5 is bent by pulling the operation wire in conjunction with the turning operation of the angle knob 8. The imaging region by the endoscope 1 is changed by changing the direction of the distal end portion 4 in accordance with the bending operation by the above operation. The operation unit 7 is connected to the video processor 2 via a universal cable 9 and a base unit 10. Furthermore, the video processor 2 is connected to a monitor 3.

  FIG. 2 is a block diagram illustrating a configuration of the base 10 and the video processor 2 of the endoscope 1. The base 10 and the video processor 2 are optically or electrically connected via an outgoing optical fiber connector 17, a light receiving fiber connector 18, and an electrical connector 19. Light sources 23a to 23c of the video processor 2 emit light having wavelengths corresponding to R, G, and B colors, respectively. The lights emitted from the light sources 23a to 23c are respectively guided to the optical multiplexer 20 and combined with white light. The white light combined by the optical multiplexer 20 is propagated to the outgoing optical fiber connector 17 by the optical fiber. The outgoing optical fiber 13 is connected to the outgoing optical fiber connector 17 which is an optical coupling means. The outgoing optical fiber 13 is inserted from the base portion 10 of the endoscope 1 into the universal cable 9, the operation portion 7, the flexible tube 6, and the bending portion 5, and extends to the distal end portion 4. Therefore, the white light propagated to the outgoing optical fiber connector 17 is propagated to the outgoing end of the outgoing optical fiber 13 at the distal end portion 4.

  The exit end of the exit optical fiber 13 is moved by the scanning means provided at the distal end portion 4 so as to draw a spiral locus, and the white light emitted from the exit end travels to the target site. White light as return light reflected by the target portion is incident on the end face of the light receiving fiber 14 disposed at the distal end portion 4. Details of the configuration of the distal end portion 4 and the operation of the scanning means will be described later. Similarly to the outgoing optical fiber 13, the light receiving fiber 14 is inserted from the base portion 10 to the universal cable 9, the operation portion 7, the flexible tube 6, and the bending portion 5, and extends to the distal end portion 4. Therefore, the return light from the target site is propagated from the distal end portion 4 to the base portion 10. Then, the return light propagated to the base 10 by the light receiving fiber 14 is guided to the light receiver 21 of the video processor 2 through the light receiving fiber connector 18 and the optical fiber. In the light receiver 21, the return light is separated into R, G, and B components by an optical element such as a dichroic mirror and a dichroic prism and guided to a photomultiplier tube for detecting each component. The R, G, and B component lights detected by each photomultiplier tube are photoelectrically converted and then sent to the video signal processing circuit 24.

  The video signal processing circuit 24 performs various signal processing such as clamp, knee, γ correction, interpolation processing, and AGC (Auto Gain Control) on the input signal, and then converts the processed signal into a digital signal sequence. To the image memory 26. The image memory 26 buffers the input image signal in units of frames. The video signal processing circuit 24 sends the image signal swept from the image memory 26 at a predetermined timing to the video signal output circuit 27. The video signal output circuit 27 converts the image signal into a video signal conforming to a predetermined standard such as NTSC (National Television System Committee) or PAL (Phase Alternating Line), and outputs the video signal to the monitor 3. As a result, a color image of the target part is displayed on the monitor 3.

  Information about the endoscope 1 is stored in the memory 11 of the base 10. The sub CPU 16 reads out information necessary for the operation of the scanning means of the distal end portion 4 from the memory 11 and designates necessary setting values for the scanning driver 15. In addition, when the endoscope 1 is connected to the video processor 2, the sub CPU 16 stores the identification information of the endoscope 1 and the property information of the scanning unit among the information stored in the memory 11 in the video processor 2. Information necessary for the above processing is transmitted to the CPU 25 of the video processor 2 through the electrical connector 19.

  The CPU 25 stores information acquired from the sub CPU 16 via the electrical connector 19 in the memory 22. The CPU 25 sends a signal necessary for controlling the endoscope 1 such as scanning means to the sub CPU 16. Further, the CPU 25 controls the light amounts of the light sources 23 a to 23 c and the image processing in the video signal processing circuit 24.

  Here, the configuration of the distal end portion 4 of the endoscope 1 will be described in detail with reference to FIG. As shown in FIG. 3, the Z axis is defined in the longitudinal direction of the insertion portion 4, and the direction toward the distal end side of the insertion portion 4 is defined as a positive Z direction. A plane perpendicular to the Z axis is defined as a plane (XY plane) in the XY orthogonal coordinate system. A direction perpendicular to the paper surface and proceeding to the back is defined as a positive X direction, and an upward direction on the paper surface is defined as a positive Y direction. A midway portion on the distal end side of the outgoing optical fiber 13 is inserted into a cylindrical or box-shaped piezoelectric element unit including a piezoelectric element 30 and an electrode 31, and is bonded to the distal end of the piezoelectric element unit by an adhesive 35. It is fixed. The piezoelectric element unit is fixed in the sheath 34 by a fixing material 33. Electric wires 32 a to 32 d are connected to the electrode 31, and each electric wire is connected to an X-axis driver (not shown) or a Y-axis driver (not shown) in the scanning driver 15 of the base 10.

  The piezoelectric element 30 includes a pair of actuators that resonate the tip of the outgoing optical fiber 13. The actuator is a piezoelectric actuator. The X-axis driver applies a first AC voltage to one actuator based on the drive control signal transmitted from the scanning driver 15. Further, the Y-axis driver applies a second AC voltage whose phase is orthogonal to the other actuator based on the drive control signal transmitted from the scanning driver 15 at the same frequency as the first AC voltage.

  The two actuators vibrate in accordance with the applied first and second AC voltages, and cause a resonance motion in the X-axis direction and the Y-axis direction of the tip of the outgoing optical fiber 13. As a result, the output end of the output optical fiber 13 is centered on the central axis AX of the insertion portion 4 on a surface that approximates the XY plane by combining the kinetic energy in the X-axis direction and the Y-axis direction generated by the actuator. Draw a locus of a circle with a predetermined radius.

  Then, the application of the AC voltage to the actuator is stopped in a state where the tip of the outgoing optical fiber 13 draws a circular locus with a predetermined radius, and the resonance of the tip of the outgoing optical fiber 13 is attenuated. Due to this attenuation, the tip of the outgoing optical fiber 13 moves toward the central axis AX while drawing the locus of the spiral pattern on a plane that approximates the XY plane, and finally stops on the central axis AX. After the tip of the outgoing optical fiber 13 stops on the central axis AX, an AC voltage is applied again to each actuator, and the tip of the outgoing optical fiber 13 is in a state of drawing a locus of a circle with the predetermined radius. Thus, the tip of the outgoing optical fiber 13 repeats the above operation. The white light emitted from the outgoing optical fiber 13 is reflected by the target portion and enters the tip surface of the light receiving fiber 14.

  Next, the light amount correction in the present embodiment will be described with reference to FIG. In the base 10 of the endoscope 1, a light receiving element 12 is provided in the vicinity of the outgoing optical fiber 13 so as to face the outgoing optical fiber 13. As the light receiving element 12, a photodiode, an avalanche photodiode, a photomultiplier tube, or the like is used. The light receiving element 12 is disposed on the substrate of the endoscope 1. Light leaked from the side surface of the outgoing optical fiber 13 is received by the light receiving element 12, the received light amount is converted into an electric signal and A / D converted by the signal processing circuit 42, and then the sub CPU 16 via the signal output unit 43. Is output.

  Here, the sensitivity of the light receiving element 12 and the signal amount of the output signal will be described with reference to the graphs of FIGS. Consider a case in which the light receiving element 12 receives light of R, G, and B wavelengths having the same light amount, that is, the same output, as shown in FIG. As shown in the graph of FIG. 5B, the light receiving element 12 has a light receiving sensitivity characteristic in which the sensitivity increases from a short wavelength to a long wavelength. Accordingly, when the signal amount of the output signal at the maximum sensitivity of the light receiving element 12 is 100, the light receiving element 12 that has received the R, G, and B wavelengths of the same light amount is shown in FIG. 5C. , G, and B light, the output signal amount is 90, 70, and 30, respectively, and signals having different signal amounts are output.

FIGS. 6A to 6C are flowcharts of the light amount correction process in the present embodiment. In the present embodiment, the emitted light amounts S _R0 , S _G0 , S _{B0 of} the light sources 23 a to 23 c based on the initial setting values of the R, G, and B lights, and R, G, Data such as received light amounts O _R0 , O _G0 , and O _B0 in the light receiving element 12 when each light of B is emitted are stored in the memories 11 and 22 in advance at the time of shipment from the factory. In the present embodiment, light amount correction of R light among R, G, and B light is first performed. FIG. 6A shows a flowchart of the R light amount correction process. First, in step S101, the CPU 25 reads each value of S _R0 , S _G0 , S _B0 from the memory 22 of the video processor 2 and reads each value of O _R0 , O _G0 , O _B0 from the memory 11 of the endoscope 1. After reading the data at the time of factory shipment, the process proceeds to step S103.

In step S103, the received light amount comparison circuit 28 calculates the received light amount O _R1 in the light receiving element 12 when the output of the light source 23a is 50% of S _R0 . Here, the output of the light source 23a is set to 50% of _SR0 in order to guarantee at the time of light quantity correction. Therefore, by setting the output of the light source to a value smaller than the factory default value, the emitted light quantity of the light source at the time of light quantity correction can be surely kept within the safe range. Of course, an arbitrary ratio may be adopted, or the light source 23 may be output by setting the value S _R0 at the time of factory shipment. Next, in step S105, the amount of emitted light is set to 50% of S _R0 and R light is emitted from the light source 23a. Then, in step S107, measuring the received light amount _{O R2} by the light receiving element 12, the measurement result is sent to the light receiving amount comparison circuit 28 via the CPU 25.

In step S109, the received light amount comparison circuit 28 compares the _{O R2} and _{O R1,} and determines whether these two values are substantially equal. When it is determined that the values are substantially equal, the CPU 25 determines that it is not necessary to correct the light amount of the light source 23a, ends the R light amount correction process, and proceeds to the G light amount correction process. _Further, if _{the O R2} and _{O R1} is not determined to be approximately equal, the process proceeds to step S111 considers that it is necessary to correct the light quantity of the light source 23a.

In step S111, it determines whether the received light amount comparison circuit 28 or _{O R2} is 20% or less of _{O R1.} If O _R2 is 20% or less of O _R1 is dust adhesion and large scratches on the connecting portion of the outgoing optical fiber connector 17, the outgoing optical fiber 13 to a fatal defect such as axial deviation occurs There is a high possibility that the amount of R light propagating is extremely reduced. Therefore, the process proceeds to step S113 without performing the light quantity correction process, and an error is displayed on the monitor 3, and the light quantity correction process of the present embodiment is terminated. When the error is displayed on the monitor 3, the surgeon appropriately performs operations such as dust removal and replacement of the outgoing optical fiber connector 17, and then executes the light amount correction processing of this embodiment again. If O _R2 is not less than 20% of O _R1 is potentially fatal defect as described above has occurred is low, the need to promote the work of removal and replacement of dust surgeon with an error since it can be regarded that there is no, the process proceeds to step S115, CPU 25 has a light quantity correction means performs a process of the light receiving amount of the light receiving element 12 changes the light emission amount of the light source 23a until the _{O R1.} When O _R2 = O _R1 , the R light quantity correction process is terminated, and the process proceeds to the G light quantity correction process. As the criterion for determining whether _{O R2} and _{O R1} is approximately equal at step _S109, the allowable range, such as for example whether or not the difference between the _{O R2} and _{O R1} falls within 10% of _{O R1} and to within 20% Can be used. Further, in step _S111, it is possible _{to O R2} is instead equal to or smaller than 20% of _{O R1, O R2} to determine whether more than 50% of the _{O R1.} Thereby, even when it is not necessarily highly likely that a fatal defect has occurred, it is possible to provide a configuration that prompts the operator to check the state of the outgoing optical fiber connector by displaying an error. .

Next, the G light amount correction process will be described with reference to FIG. In step S201, the received light amount comparison circuit 28 calculates the received light amount O _G1 in the light receiving element 12 when the output of the light source 23b is 50% of S _G0 . Also here, the output of the light source 23b may be set to an arbitrary ratio other than 50% of S _G0 , or may be set to a factory default value S _G0 . Next, in step S203, the amount of emitted light is set to 50% of S _G0 and G light is emitted from the light source 23b. In step S <b> 205, the light reception amount OG <b> ₂ by the light receiving element 12 is measured, and the measurement result is sent to the light reception amount comparison circuit 28.

In step S207, the received light amount comparison circuit 28 compares the _{O G2} and _{O G1,} it is determined whether the two values are approximately equal. When it is determined that the values are substantially equal, the CPU 25 regards that it is not necessary to correct the light amount of the light source 23b, ends the G light amount correction process, and proceeds to the G light amount correction process. _Further, if _{the O G2} and _{O G1} is not determined to be approximately equal, the process proceeds to step S209 considers that it is necessary to correct the light quantity of the light source 23b. As in the R light quantity correction processing, whether or not the difference between O _G2 and O _G1 falls within 10% or 20% of O _G1 is used as a criterion for determining whether O _G2 and O _G1 are substantially equal. An acceptable range such as can be used.

In step S209, it determines whether the received light amount comparing circuit 28 is 20% or less of _{O G2} is _{O G1.} If O _G2 is 20% or less of O _G1 , as in step S111 in the first embodiment, the process proceeds to step S211 without performing the correction process, and an error is displayed on the monitor 3, and the light amount of this embodiment The correction process ends. When the error is displayed on the monitor 3, the surgeon appropriately performs operations such as dust removal and replacement of the outgoing optical fiber connector 17, and then executes the light amount correction processing of this embodiment again. If O _G2 is not less than 20% of _{O G1,} the process proceeds to step S213, the light amount is a correction means CPU25 performs a process for changing the amount of emitted light of the light source 23b to the light receiving amount of the light receiving element 12 becomes _{O G1.} When O _G2 = O _G1 , the G light quantity correction process is terminated, and the process proceeds to the B light quantity correction process. In the G light quantity correction processing, whether or not O _G2 is 50% or less of O _G1 is determined instead of determining whether or not O _G2 is 20% or less of O _G1 in Step S209. Can be determined. As shown in FIG. 6C, the light amount correction process for the B light is performed by using S _B0 , O _B1 , and the received light amount _OB2 by the light receiving element 12 instead of S _G0 , O _G1 , and O _G2. Since it is the process of the same conditions and content as the light quantity correction process of G light, description is abbreviate | omitted. By executing the above light amount correction processing of each R, G, B light, the ratio of the R, G, B light of the illumination light emitted from the distal end of the endoscope, that is, the color balance can be set at the time of shipment from the factory. In accordance with the state, the amount of light emitted from the light source can be set to a suitable value.

  When the target part is imaged using the endoscope apparatus 100 after the above light amount correction processing is completed, the R, G, and B lights emitted from the light sources 23a to 23c are converted into white light by the optical multiplexer 20. The signals are combined and output to the target site via the output optical fiber connector 17 and the output optical fiber 13 by the scanning mechanism of the distal end portion 4. When changing the amount of white light emitted to the target part during imaging, the R, G, B light corrected by the light amount correction process based on the amount of white light leakage detected by the light receiving element 12 is used. While maintaining the ratio, with the upper limit of the amount of white light when light is emitted from each light source at the initial set value, the control voltage of the light sources 23a to 23c is changed to change the amount of light emitted from each of the R, G, and B lights. adjust.

  Here, another method for adjusting the amount of white light after the light amount correction processing will be described. In the present embodiment, a period from when the application of the AC voltage to the actuator of the piezoelectric element 30 is stopped to when the tip of the outgoing optical fiber 13 is scanned on a plane that approximates the XY plane and stops on the central axis AX (a spiral pattern). The target part is imaged during a period). A period between the spiral pattern periods is an interruption period in which imaging is not performed. Therefore, in the spiral pattern period, the light sources 23a to 23c are simultaneously turned on to emit the R, G, and B light to capture the target region, and in the interruption period, individual lighting is performed to turn on any of the light sources 23a to 23c. The amount of R, G, B light emitted from each light source is detected by switching and the light receiving element 12, and the ratio of R, G, B light set by the above light amount correction processing is maintained. , G, and B can be confirmed that the amount of light does not exceed the initial setting value, and the amount of light emitted from each light source can be controlled as necessary. Since imaging is performed by scanning while periodically repeating the spiral pattern period and the interruption period, the interruption period occurs periodically, so that the amount of white light can be adjusted periodically and automatically.

  Next, an endoscope apparatus according to a second embodiment of the present invention will be described. The endoscope used for the endoscope apparatus according to the present embodiment is a confocal endoscope. FIG. 7 is a block diagram showing the endoscope base 210 and the video processor 220 of the endoscope apparatus according to this embodiment. The light emitted from the light source 223 is propagated to the confocal optical unit 200 at the distal end portion of the endoscope via the optical demultiplexer / multiplexer 221, the outgoing optical fiber connector 216, and the outgoing optical fiber 213. A damper 222 for terminating the light emitted from the light source 223 without reflection is connected to the optical demultiplexer / multiplexer 221.

  FIG. 8 is a schematic diagram showing a configuration of the confocal optical unit 200 incorporated in the distal end portion of the endoscope. For convenience, the longitudinal direction of the confocal optical unit 200 is the positive Z direction, and the X direction and the Y direction that are orthogonal to the Z direction and orthogonal to each other are set. Further, the upward direction in FIG. 7 is defined as a positive X direction, and the direction toward the front side of the sheet is defined as a positive Y direction.

  As shown in FIG. 8, the confocal optical unit 200 has a metal outer cylinder 201 that houses each component of the unit. The outer cylinder 201 holds an inner cylinder 202 having an outer wall surface shape corresponding to the inner wall surface shape of the outer cylinder 201 coaxially and slidably in the Z direction. The exit end of the exit optical fiber 213 is supported inside the inner cylinder 202 through openings formed in the base end surfaces of the outer cylinder 201 and the inner cylinder 202. The outer cylinder 201 has an objective optical system 203. The objective optical system 203 has a plurality of optical lenses held by a lens frame (not shown). The lens frame is fixed and supported relative to the inner cylinder 202 inside the outer cylinder 201. Therefore, the optical lens group held by the lens frame slides in the Z-axis direction integrally with the inner cylinder 202 inside the outer cylinder 201.

  The vicinity of the exit end of the exit optical fiber 213 is vibrated by a piezoelectric actuator (not shown). This piezoelectric actuator is driven and controlled by the scanning driver 214 of the base 210. The exit end of the exit optical fiber 213 periodically moves on a surface that approximates the XY plane by the vibration of the piezoelectric actuator. The light emitted from the emission end is focused on the objective optical system 203, and the object is two-dimensionally scanned as the emission end moves on a plane that approximates the XY plane.

  The confocal optical unit 200 includes a compression coil spring 204 between the base end surface of the inner cylinder 202 and the inner wall surface of the outer cylinder 201. The compression coil spring 204 is sandwiched between the base end surface of the inner cylinder 202 and the inner wall surface of the outer cylinder 201 in an initially compressed state from the natural length along the Z direction. The confocal optical unit 200 has a rod-shaped shape memory alloy 205 that is long in the Z direction. When the shape memory alloy 205 is heated by energization, it contracts in the Z direction against the restoring force of the compression coil spring 204. The inner cylinder 202 fixed to one end of the shape memory alloy 205 moves back in the Z direction along with the outgoing optical fiber 213 supported by the inner cylinder 202 as the shape memory alloy 205 contracts. The amount of contraction of the shape memory alloy 205 is controlled by the amount of current supplied to the shape memory alloy 205.

  The light emitted from the emission end of the emission optical fiber 213 is focused on the surface or surface layer of the target site via the objective optical system 203. This focal position is displaced in the Z direction in accordance with the advance and retreat of the exit end of the exit optical fiber 213. That is, the confocal optical unit 200 performs three-dimensional movement of the emitting end by the piezoelectric actuator and three-dimensional movement of the emitting end by the compression coil spring 204 and the shape memory alloy 205 in one axis direction. Scan.

  The light scanned on the target part by the confocal optical unit 200 is reflected by the target part, returns to the outgoing optical fiber 213, propagates through the outgoing optical fiber 213 as return light, and passes through the outgoing optical fiber connector 216. Proceed to the demultiplexer / multiplexer 221. Then, it is branched from the optical path of the light from the light source 223 by the optical demultiplexer / multiplexer 221, propagates through the light receiving fiber 224, and enters the light receiver 225. The return light is converted into a light reception signal by the light receiver 225 and output to the video signal processing circuit 226.

  The video signal processing circuit 226 performs various signal processing on the input signal, converts the processed signal into a digital signal sequence, and outputs the digital signal sequence to the image memory 230. The image memory 230 buffers the input image signal in units of frames. The video signal processing circuit 226 sends the image signal swept from the image memory 230 at a predetermined timing to the video signal output circuit 227. The video signal output circuit 227 converts the image signal into a video signal conforming to a predetermined standard such as NTSC or PAL, and outputs the video signal to the monitor. Thereby, the observation image of the target part is displayed on the monitor.

  Information relating to the endoscope is stored in the memory 211 of the base 210. The sub CPU 215 reads information necessary for the operation of the confocal optical unit 200 from the memory 211 and designates a setting value necessary for the scan driver 214. In addition, when the endoscope is connected to the video processor 220, the sub CPU 215 stores the identification information of the endoscope and the property information of the confocal optical unit 200 among the information stored in the memory 211 within the video processor 220. Information necessary for this processing is transmitted to the CPU 229 of the video processor 220 via the electrical connector 217.

  The CPU 229 stores information received from the sub CPU 215 via the electrical connector 217 in the memory 228. The CPU 229 sends a signal necessary for controlling the endoscope such as the confocal optical unit 200 to the sub CPU 215. In addition, the CPU 229 performs control of the light amount of the light source 223 and image processing in the video signal processing circuit 226.

  Also in the present embodiment, as in the first embodiment, the light receiving element 212 receives light leaked from the outgoing optical fiber 213 when light is emitted from the light source 223 at the factory setting at the initial setting value. Data such as the amount of emitted light 223 and the amount of light received by the light receiving element 212 are stored in the memories 211 and 228 in advance. Then, similarly to the first embodiment shown in FIG. 6A, light is emitted from the light source 223 with a predetermined amount of emitted light, and the amount of light received by the light receiving element 212 is a desired value based on data at the time of factory shipment. As in the first embodiment, light amount correction processing is performed.

  In order to perform confocal observation, drug fluorescence observation, autofluorescence observation, and the like, light having a short wavelength may be emitted from the light source 223. As shown in the graph of FIG. 5B, the light receiving element has a light receiving sensitivity characteristic in which the sensitivity increases from a short wavelength to a long wavelength. Therefore, when light having a short wavelength shown in FIG. 9A is emitted from the light source 223, the sensitivity of the light receiving element 212 to this light is low as shown in FIG. 9B, as shown in FIG. 9C. In addition, the amount of signal output from the light receiving element 212 is small. Therefore, as shown in FIG. 10, a fluorescent member that emits fluorescence by applying light at the wavelength of light emitted from the light source 223 is applied to the light receiving surface of the light receiving element 212. Further, similar fluorescent members 212a and 212b may be applied to the periphery of the light receiving element 212, the portion of the outgoing optical fiber 213 facing the light receiving element 212, and the like. As a result, as shown in FIG. 9 (c), the leakage light from the outgoing optical fiber 213 is converted into light having a high light receiving sensitivity of the light receiving element 212, and the short wavelength leakage light is also detected with high sensitivity. It is possible to improve the accuracy of light amount control in the above light amount correction processing. In addition, as a material used for the fluorescent members 212a and 212b, for example, when emitting light having a blue or blue-violet wavelength from the light source 223, a sialon phosphor is used, and when emitting light having a green wavelength from the light source 223, Boron dipyrromethene can be used.

  In a conventional confocal endoscope, an optical demultiplexer is provided on the endoscope side to monitor the amount of illumination light on the endoscope side, and the light output from the optical demultiplexer is received. It was necessary to receive light with the element. For this reason, it is complicated to use an optical demultiplexer / multiplexer, a light receiving optical fiber for propagating return light from the target site, and an optical connector for connecting the light receiving optical fiber between the endoscope and the video processor. It is necessary to provide a member having such a structure in the endoscope, which may hinder the reduction in size and diameter of the endoscope. However, as described in the second embodiment, according to the present invention, the light demultiplexing / multiplexing unit is provided on the video processor side, and the endoscope is downsized, and the amount of illumination light is reduced with a simple configuration on the endoscope side. Can be detected and corrected.

  The above is the description regarding the embodiment of the present invention. The present invention is not limited to the above-described configuration, and various modifications can be made within the scope of the technical idea of the present invention. For example, the light receiving element does not need to be provided on the base or disposed on the substrate, and can be disposed at an arbitrary position where light leaked from the outgoing optical fiber can be received. In the above description, data used as a reference for light amount correction in the light amount correction process is data acquired at the time of shipment from the factory, but data may be acquired at the first connection after shipment. In the above description, the scanning endoscope and the confocal endoscope are used. However, in addition to the spectroscopic endoscope, the above configuration is applied to an endoscope and a probe capable of a therapeutic function and laser ablation. By doing so, the effects of the present invention can be achieved.

  In addition, the ratios of the R, G, and B lights that are required vary depending on the target site to be observed and the type of observation to be performed. Therefore, it is also possible to store in the memories 11 and 22 data serving as a reference for light amount correction in the light amount correction process for each ratio of R, G, and B light according to various observations. For example, in the above description, the amount of light received by the light receiving element 12 when each color light is emitted from each light source at the ratio of R, G, B light according to various observations is stored in the memories 11 and 22 at the time of shipment from the factory. Alternatively, a configuration may be adopted in which data serving as a reference for light amount correction is read according to the type of observation designated by the surgeon at the start of the light amount correction process. Further, data used as a reference for light quantity correction in the light quantity correction process can be stored in the endoscope-side memory, and data necessary for connection to the video processor can be stored in the video processor-side memory. In the above description, the light amount correction processing is performed in the order of R light, G light, and B light, but the light amount correction processing can be performed in an arbitrary order.

DESCRIPTION OF SYMBOLS 1 Endoscope 4 Front-end | tip part 12,212 Light receiving element 13,213 Outgoing optical fiber 17,216 Outgoing optical fiber connector 23a, 23b, 23c, 223 Light source 25,229 CPU
28, 231 Received light amount comparison circuit 200 Confocal optical unit 212a, 212b Fluorescent member

Claims (9)

A light source that emits light having a predetermined wavelength band;
An outgoing optical fiber coupled with light from the light source via optical coupling means and propagating the light;
Scanning means for scanning light propagated by the outgoing optical fiber over a target site;
A light receiving element for receiving leakage light from the outgoing optical fiber;
A light amount correction means for correcting the amount of light emitted from the light source based on the amount of light received by the light receiving element,
An endoscope apparatus characterized by that. The endoscope apparatus further includes a received light amount comparing means for comparing a received light amount of the light receiving element with a first threshold value,
The light amount correction unit corrects the amount of light emitted from the light source based on a comparison result by the received light amount comparison unit.
The endoscope apparatus according to claim 1. The light amount correction means includes
When the result of comparison by the received light amount comparing means indicates that the received light amount of the light receiving element is different from the first threshold value, the emitted light amount of the light source is corrected,
When the comparison result by the received light amount comparison means indicates that the received light amount of the light receiving element is equal to the first threshold value, correction of the emitted light amount of the light source is not performed.
The endoscope apparatus according to claim 2. The received light amount comparing means compares the received light amount of the light receiving element with a second threshold value smaller than the first threshold value when the received light amount of the light receiving element is different from the first threshold value;
The light amount correction unit does not correct the emitted light amount of the light source when the comparison result by the received light amount comparison unit indicates that the received light amount of the light receiving element is smaller than the second threshold value.
The endoscope apparatus according to claim 3.   5. The endoscope apparatus according to claim 1, further comprising a threshold setting unit configured to set the first threshold based on an initial setting value of an emitted light amount of the light source. The endoscope apparatus described in 1.   The endoscope apparatus according to any one of claims 1 to 5, wherein the light receiving element is disposed in the vicinity of the optical coupling unit.   5. The endoscope apparatus according to claim 4, further comprising notification means for notifying that a result of comparison by the received light amount comparing means is that a received light amount of the light receiving element is smaller than the second threshold value. The endoscope apparatus according to any one of Items 6. The predetermined wavelength band includes wavelengths of light of red (R), green (G), and blue (B).
The first and second threshold values are set for each of R, G, and B light,
The received light amount comparing means compares the received light amount received by the light receiving element for each of R, G, and B from the light source with the first threshold value for each of R, G, and B light, When the amount of light received by the light receiving element is different from the first threshold, the amount of light received by the light receiving element is compared with the second threshold for each of R, G, and B light;
The light amount correcting means emits light from the light source when the result of comparison by the received light quantity comparing means indicates that the received light quantity of the light receiving element is smaller than the second threshold value for each of R, G, and B light. Correct the amount of light,
The endoscope apparatus according to any one of claims 4 to 7, wherein the endoscope apparatus is characterized. The predetermined wavelength band includes a wavelength at which the light receiving sensitivity of the light receiving element is low,
At least one of the light-receiving surface of the light-receiving element, the vicinity of the light-receiving element, and the outgoing optical fiber is coated with a fluorescent member that emits fluorescence when excited at a wavelength at which the light-receiving sensitivity of the light-receiving element is low.
The endoscope apparatus according to any one of claims 1 to 8, wherein the endoscope apparatus is characterized in that:

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