JP2010051650A - Endoscope system, and method for detection of optical fiber breakage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a breakage condition of an optical fiber automatically in real time. <P>SOLUTION: Optical fibers 65 composing a light guide 35 inserted into an electronic endoscope 10 are each covered with a conductive film 67. A specific voltage is applied to the conductive film 67, and the current value running through the conductive film 67 is measured. A comparison circuit 57 of a light source device 12 compares the measured current value with a reference value. In a case where the measured current value is greater than the reference value, a CPU 60 determines that a specified number or more of the optical fibers 65 are broken, and warns for replacement of the electronic endoscope 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an endoscope system and a breakage detection method suitable for detecting breakage of a plurality of optical fibers constituting a light guide for guiding light inserted through an endoscope.

  In recent years, endoscope systems have been widely used in the medical field and the industrial field. An endoscope system includes an endoscope that incorporates a solid-state imaging device at a distal end of a thin and bendable insertion portion, a processor device that receives an imaging signal from the solid-state imaging device of the endoscope, and generates an image; The light source device supplies illumination light for illuminating the subject to the endoscope. A light guide is disposed inside the endoscope, and illumination light supplied from the light source device is guided to the distal end of the endoscope via the light guide, and from an illumination window provided at the distal end. The subject is illuminated.

  The light guide is configured by bundling a plurality of optical fibers with a converging material such as a wound tape. These optical fibers are cured over time due to the properties of the materials. In an endoscope, since an insertion portion is bent at a sharp angle when used, the optical fiber may be broken by the pressure of bending when the optical fiber is cured. Then, light leaks from the broken part, and the amount of illumination light applied to the subject decreases.

While the number of broken optical fibers is small, the decrease in the amount of illumination light is not so serious and does not hinder the use of the endoscope. However, when a predetermined number or more of optical fibers are broken, the amount of illumination light applied to the subject is remarkably reduced, so that the endoscopic image becomes dark and the amount of information is reduced, resulting in misdiagnosis and the like. Result. Therefore, conventionally, when the endoscope system is not used, the light guide is regularly checked for breakage (see, for example, Patent Document 1).
JP-A-60-35709

  However, the above-described conventional technique requires a complicated operation of installing a white plate at the distal end of the endoscope and performing photometry. In addition, it is necessary to provide time for inspection regularly, which is a burden on the user in terms of operation and time.

  Furthermore, in the prior art, it is impossible to know the breakage of the optical fiber during the use of the endoscope. As a result, the amount of illumination light suddenly decreases during use of the endoscope, and there is a risk that the use may be interrupted. In particular, if the breakage is not inspected for a long period of time, the possibility that the optical fiber breaks unexpectedly cannot be excluded, and the user is stressed.

  The present invention has been made in view of the above problems, and an endoscope system and an optical fiber breakage detection method capable of automatically and in real time detecting a breakage state of an optical fiber constituting a light guide. The purpose is to provide.

  In order to achieve the above object, an endoscope system according to the present invention includes a conductive film, a power feeding unit, and a determination unit. The conductive film individually covers a plurality of optical fibers constituting the light guide for guiding light inserted through the endoscope. The power supply means supplies a predetermined level of power to the conductive film. And a determination means determines the break condition of an optical fiber based on the change of the electric power applied to the some optical fiber covered with the electrically conductive film.

  The conductive film is preferably applied or sputtered on the outer peripheral surface of the optical fiber. Furthermore, the conductive film is preferably made of a conductive resin, copper, or indium tin oxide.

  In a preferred embodiment of the present invention, the power supply means is a constant voltage source that applies a constant voltage to the conductive film, and the determination means is an ammeter that measures a current flowing through the conductive film, and a measurement value of the ammeter is a reference value. And a comparison circuit for comparison. This reference value is stored in a storage means provided in the endoscope system.

  The determination means preferably further determines whether or not the light guide can withstand use based on the determination result of the breakage status. Moreover, it is preferable to further include display means for displaying the determination result of the determination means.

  An optical fiber breakage detection method according to the present invention supplies a predetermined level of electric power to a conductive film that individually covers a plurality of optical fibers constituting a light guide for light guide inserted through an endoscope. The present invention is characterized in that a breakage state of an optical fiber is determined based on a change in electric power applied to a plurality of covered optical fibers.

  According to the present invention, power is supplied to the conductive film covering each optical fiber constituting the light guide, and the change in the power is monitored to determine the breakage state of the optical fiber. And can be detected in real time. Therefore, a complicated operation for checking the breakage of the optical fiber becomes unnecessary.

  Further, even when the endoscope is in use, the broken state of the optical fiber can be detected, so that the inspection time and replacement time of the endoscope can be accurately grasped. As a result, a situation in which the endoscope cannot be used during the examination can be avoided, and the stress on the user during the examination is reduced.

  Furthermore, since the conductive film is formed on the outer peripheral surface of the optical fiber, it does not hinder the diameter reduction of the endoscope and does not hinder the bending operation.

  As shown in FIG. 1, the endoscope system 2 illuminates the inside of the body cavity, the electronic endoscope 10 that images the inside of the body cavity of the subject, the processor device 11 that generates the endoscope image from the imaging signal. The light source device 12 supplies illumination light for the purpose. The electronic endoscope 10 includes a flexible insertion portion 13 that is inserted into a body cavity, an operation portion 14 that is connected to a proximal end portion of the insertion portion 13, and a universal cord 15 that is connected to the operation portion 14. And.

  A bending portion 16 that connects a plurality of bending pieces is formed at the distal end of the insertion portion 13. At the distal end of the bending portion 16, a distal end portion 17 incorporating an optical system for in-vivo imaging is continuously provided. The bending portion 16 is bent in the vertical and horizontal directions by operating the angle knob 18 provided in the operation portion 14 and pushing and pulling the wire inserted in the insertion portion 13. Thereby, the front-end | tip part 17 is orient | assigned to the desired direction in a body cavity.

  A connector 19 is connected to the extended tip of the universal cord 15. The connector 19 is a composite type connector including a communication connector and a light source connector, and the electronic endoscope 10 is detachably connected to the processor device 11 and the light source device 12 through the connector 19.

  As shown in FIG. 2, the electronic endoscope 10 includes a CCD 25 at the distal end portion 17 and an analog signal processing circuit (AFE: Analog Front End) 26 at the operation portion 14. On the end face of the distal end portion 17, there are provided an observation window 27 for taking in the image light of the subject and an illumination window 28 to which illumination light is irradiated. In the back of the observation window 27, an objective optical system 29 and a prism 30 are arranged. The subject light that has passed through the objective optical system 29 and the prism 30 enters the light receiving surface of the CCD 25. The CCD 25 outputs an imaging signal based on this incident light and inputs it to the AFE 26.

  The AFE 26 includes a correlated double sampling circuit (CDS) 31, an automatic gain control circuit (AGC) 32, and an analog / digital converter (A / D) 33. The CDS 31 performs correlated double sampling processing on the imaging signal input from the CCD 25 to remove reset noise and amplifier noise. The AGC 32 amplifies the imaging signal from which noise has been removed by the CDS 31 with a predetermined gain (amplification factor). The A / D 33 converts the imaging signal amplified by the AGC 32 into a digital signal having a predetermined number of bits, and inputs the digital signal to the processor device 11 via the connector 19.

  An irradiation lens 34 that irradiates a subject with illumination light is attached to the back of the illumination window 28. The irradiation lens 34 is directed to an emission end of a light guide 35 that guides illumination light from the light source device 12. The light guide 35 penetrates through the insertion portion 13, the operation portion 14, and the universal cord 15, and an incident end thereof is inserted into the light source device 12 through the connector 19.

  As shown in the cross section of FIG. 3, the light guide 35 includes a plurality of (for example, 100) optical fibers 65 made of quartz or the like, and an insulating sheath 66 that covers these optical fibers 65. As shown in FIG. 4, the outer periphery of each optical fiber 65 is covered with a conductive film 67. The conductive film 67 is a thin film formed by applying a conductive resin mixed with a low resistivity material such as graphite powder to the outer peripheral surface of the optical fiber 65. Each optical fiber 65 is hardened by a filler 69 injected between the optical fibers in the vicinity of both ends thereof, and is bundled into one optical fiber bundle. The filler 69 is made of a resin mixed with a conductive material and electrically connects the conductive films 67 of the optical fibers 65. Further, in order to electrically isolate each optical fiber 65, the outer periphery of the conductive film 67 is coated with an insulating film 68 except for the vicinity of both ends solidified by the filler 69. The conductive film 67 of each optical fiber 65 is connected to a constant voltage source 55 and an ammeter 56 (both see FIG. 2) of the light source device 12 via electrodes 69a and 69b (see FIG. 5) formed on the filler 69. Has been. The conductive film 67 may be made of conductive paint such as copper, ITO (indium tin oxide) ink, or the like, or may be formed by sputtering.

  Returning to FIG. 2, the processor device 11 supplies power to the electronic endoscope 10 via a transmission cable inserted into the universal cord 15 and receives an imaging signal from the electronic endoscope 10 to receive an image. Generate data. The image data generated by the processor device 11 is displayed on the monitor 20 (see also FIG. 1) as an endoscopic image. The processor device 11 is electrically connected to the light source device 12 and controls the operation of the endoscope system 2 in an integrated manner.

  The processor device 11 includes a timing / driver circuit 40, a digital signal processing circuit (DSP) 41, a digital / analog converter (D / A) 42, and a CPU 44 that comprehensively controls these units. The timing / driver circuit 40 is connected to the CCD 25 via a transmission cable. The timing / driver circuit 40 inputs a timing signal (clock pulse) to the CCD 25 in accordance with an instruction from the CPU 44. By this timing signal, the timing for reading the accumulated charge from the CCD 25, the shutter speed of the electronic shutter of the CCD 25, and the like are controlled.

  The DSP 41 performs color separation, color interpolation, gain correction, white balance adjustment, gamma correction, and the like on the imaging signal input from the AFE 26 of the electronic endoscope 10 to generate image data. This image data is converted into an analog signal by the D / A 42 and input to the monitor 20. Thereby, an endoscopic image is displayed on the monitor 20.

  The light source device 12 includes a light source 50, a light source driver 51, an aperture adjustment mechanism 52, an iris driver 53, a condensing lens 54 that guides illumination light to the incident end of the light guide 35, a constant voltage source 55, and an ammeter. 56, a comparison circuit 57, a memory 58, a notification device 59, and a CPU 60 for controlling these components.

  The light source 50 is turned on and off under the control of the light source driver 51, and irradiates illumination light toward the condenser lens 54 located in front. As the light source 50, for example, a xenon lamp, a halogen lamp, an LED (light emitting diode), a fluorescent light emitting element, or an LD (laser diode) can be used.

  The aperture adjustment mechanism 52 is disposed between the light source 50 and the condenser lens 54 and adjusts the amount of illumination light so that the endoscopic image captured by the CCD 25 has substantially constant brightness. The aperture adjustment mechanism 52 includes an aperture blade that changes the diameter (diaphragm diameter) of an aperture opening through which illumination light passes, and a motor that drives the aperture blade. The diaphragm adjustment mechanism 52 is driven and controlled by the iris driver 53, and changes the passage area of the illumination light according to the change of the diaphragm diameter, thereby adjusting the amount of illumination light incident on the light guide 35.

  When an instruction to reduce the amount of illumination light is given from the CPU 60, the iris driver 53 closes the aperture blades of the aperture adjustment mechanism 52 to reduce the diameter of the illumination light. Conversely, when an instruction is given from the CPU 60 to increase the amount of illumination light, the iris driver 53 opens the aperture blades of the aperture adjustment mechanism 52 to increase the light diameter of the illumination light. Thereby, the light quantity of illumination light is adjusted.

  The constant voltage source 55 applies a constant voltage to the conductive film 67 of each optical fiber 65. The constant voltage source 55 is connected in series to the conductive film 67 together with the ammeter 56 on the proximal end side of the bundle of optical fibers 65. On the tip end side of the bundle of optical fibers 65, the conductive film 67 is connected to the signal ground of the CCD 25 via the electrode 69b and grounded. A current flows through the conductive film 67 by the voltage applied from the constant voltage source 55. The ammeter 56 measures the current flowing through the conductive film 67 and inputs the obtained current value to the comparison circuit 57.

  In FIG. 5 showing an equivalent circuit of the constant voltage source 55, the ammeter 56, and the conductive film 67, electrodes 69a and 69b are connected to both ends of the conductive film 67 of each optical fiber 65 as described above. The voltage V of the constant voltage source 55 is applied to the conductive film 67 through these electrodes 69a and 69b.

  Since the voltage V = constant, the current I measured by the ammeter 56 depends only on the resistance value R of the conductive film 67. That is, the current I decreases as the resistance value R increases, and the current I increases as the resistance value R decreases. When the bundle of optical fibers 65 is regarded as a single conductor, the resistance value R increases when the resistance of the conductor increases, that is, when the optical fiber 65 breaks and the conductive film 67 has poor conduction, or This is when it becomes non-conductive.

  The conductive film 67 is formed so that the resistance value R when the optical fiber 65 is not broken is in the range of several hundred ohms to several thousand kiloohms. If the resistance value is set lower than this range, the ammeter 56 requires high resolution, which is not practical. If the resistance value is set higher than this range, a high voltage must be applied from the constant voltage source 55, which is not practical.

  In a state where the optical fiber 65 is not broken, the resistance value of the conductive film 67 does not change from the initial value, and the ammeter 56 measures a constant current value corresponding to the resistance value. On the other hand, when the optical fiber 65 is broken, the conductive film 67 is also broken at the same time, and the level of the current flowing through the conductive film 67 is lowered. Therefore, the ammeter 56 measures a current value lower than that when no breakage occurs. That is, as shown in FIG. 6, when the optical fiber 65 is broken, the resistance value of the conductive film 67 increases, and the current value decreases as the resistance value increases. When this is viewed as the entire light guide 35, the resistance value increases and the current value decreases as the number of broken optical fibers 65 increases. Therefore, by measuring the current value of the conductive film 67, it is possible to grasp the breakage state (the presence or absence of breakage and the number of breakage) of the optical fiber 65.

  The comparison circuit 57 reads the reference value stored in advance in the memory 58 and compares the current value measured by the ammeter 56 with the reference value. When the measured current value is below the reference value, a signal indicating that fact (for example, “0”) is output to the CPU 60. The CPU 60 receives the signal and determines that the optical fiber 65 is not broken or only a small number of optical fibers 65 are broken. Further, when the measured current value exceeds the reference value, the comparison circuit 57 outputs a signal (for example, “1”) indicating that to the CPU 60. The CPU 60 receives the signal and determines that the optical fibers 65 exceeding the predetermined number are broken.

  Next, the CPU 60 determines whether or not the light guide 35 can withstand use based on the broken state of the optical fiber 65. For example, when there is no broken optical fiber 65 or the number is small, it is determined that the light guide 35 can withstand use. On the other hand, when the number of broken optical fibers 65 exceeds a predetermined number, it is determined that the light guide 35 cannot be used.

  The notification device 59 is a liquid crystal display panel provided on the front surface of the light source device 12, for example, and displays character information. The notification device 59 is controlled by the CPU 60 and displays a message corresponding to the breakage status, such as “OK” when the light guide 35 can be used and “Replacement” when the light guide 35 cannot be used. In addition, as the alarm device 59, you may notify by a LED lamp or an audio | voice other than a liquid crystal display panel. Further, a message may be displayed on the monitor 20 by communicating with the CPU 44 of the processor device 11.

  Next, the operation of the endoscope system 2 configured as described above will be described. When the power of the endoscope system 2 is turned on, the processor device 11 and the light source device 12 are activated. The CPU 60 of the light source device 12 drives the light source driver 51 to turn on the light source 50 and irradiates illumination light toward the condenser lens 54. The amount of illumination light is adjusted by passing through the aperture adjustment mechanism 52 and is incident on the condenser lens 54. The illumination light is guided to the incident end of the light guide 35 and guided to the distal end portion 17 of the electronic endoscope 10. Further, the CPU 60 drives and controls the constant voltage source 55 to apply a constant voltage to the conductive film 67 covering each optical fiber 65.

  Next, the insertion portion 13 of the electronic endoscope 10 is inserted into the body cavity, and an image in the body cavity is captured by the CCD 25 while illuminating the inside of the body cavity with the illumination light from the light source device 12. The imaging signal output from the CCD 25 is subjected to various processes by the units 31 to 33 of the AFE 26 and then input to the DSP 41 of the processor device 11. In the DSP 41, various signal processing is performed on the input imaging signal to generate image data. The image data generated by the DSP 41 is displayed as an endoscopic image on the monitor 20 via the D / A 42.

  The ammeter 56 of the light source device 12 measures the current value flowing through the conductive film 67 and inputs the obtained current value to the comparison circuit 57. When the optical fiber 65 is not broken, the ammeter 56 measures a current value at a certain level. On the other hand, when breakage occurs in the optical fiber 65, the ammeter 56 measures a lower current value than when no breakage occurs.

  The comparison circuit 57 compares the current value measured by the ammeter 56 with the reference value read from the memory 58. Based on the comparison result, the CPU 60 determines whether the optical fiber 65 is broken, and determines whether the light guide 35 can withstand use.

  In accordance with the determination result, the CPU 60 causes the alarm device 59 to display a message. When it is determined that the light guide 35 can be used, a message “OK” is displayed on the alarm device 59. On the other hand, when it is determined that the light guide 35 cannot be used, a message “replacement” is displayed on the alarm device 59 to prompt the user to replace the electronic endoscope 10. These messages are continuously displayed while the endoscope system 2 is in operation, and are changed in accordance with the change when the determination result is changed. As described above, the breakage state of the optical fiber 65 is automatically detected in real time, and whether or not the light guide 35 can withstand use is displayed as a message. It is possible to accurately grasp the time and replacement time. Further, unnecessary stress is not felt in view of the unexpected breakage of the optical fiber 65.

  In the embodiment described above, a voltage is applied to the conductive film 67 to detect the breakage state of the optical fiber 65. However, a high-frequency impulse wave is applied to the conductive film 67 to restore the shape of the reflected wave. Alternatively, the breakage status of the optical fiber 65 may be detected. In that case, a pulse wave generation circuit is provided instead of the constant voltage source 55, and a pulse wave detection circuit is provided instead of the ammeter 56.

  In the above embodiment, the constant voltage source 55 is always driven. However, the constant voltage source 55 may be driven at a constant time interval to determine breakage. Alternatively, an operation member such as an inspection button may be provided in the light source device 12, and the constant voltage source 55 may be driven only when the operation member is operated to make a breakage determination.

  Further, only one reference value is prepared and it is determined whether or not the light guide 35 can withstand use. However, a plurality of reference values may be prepared and a stepwise determination may be made. For example, the light guide 35 can be used at the present time, but it is possible to grasp the breakage situation in detail, such as when it becomes impossible to use early or late, or when there is a high risk of misdiagnosis if the use is not stopped immediately. .

  Furthermore, since the reference value varies depending on the type of electronic endoscope 10 (the number and thickness of the optical fibers 65), it is preferable to store the reference value for each type of electronic endoscope 10. In this case, when the electronic endoscope 10 is connected to the processor device 11, a reference value corresponding to the ID of the electronic endoscope 10 sent from the EEPROM or the like provided in the electronic endoscope 10 to the processor device 11 is stored in the memory. 58 and read out for comparison with the current value. The reference value may be read from a ROM provided in the electronic endoscope 10 and used.

  In the above embodiment, the determination is made based on the current value measured by the ammeter 56, but the current value may be converted into a resistance value and the determination may be made based on this.

  In the embodiment described above, a constant voltage is applied from the constant voltage source 55 to the conductive film 67 and the breakage of the optical fiber 65 is determined based on the current value measured by the ammeter 56. A constant current source may be used. In this case, a voltmeter is provided instead of the ammeter 56. As shown in FIG. 7, when the optical fiber 65 is broken, the resistance value of the conductive film 67 increases, and the output voltage value of the constant current source increases as the resistance value increases. Therefore, by measuring the output voltage value of the constant current source, it is possible to grasp the breakage status (the presence or absence of breakage and the number of breakage) of the optical fiber 65.

  In the above embodiment, when it is determined that the light guide 35 is unusable, the message “replacement” is displayed immediately. However, if the electronic endoscope 10 is prompted to be replaced during the examination, the user There is a risk of stress. Therefore, the “replacement” message may not be displayed during the inspection, and the “replacement” message may be displayed after the inspection is completed or before the next use. Further, when the endoscope system 2 is connected to a hospital LAN or the like and incorporated in a system that collectively manages the examination status and the like by the host computer, the broken status of the optical fiber 65 may be notified only to the host computer. . Thereby, it can avoid giving unnecessary stress to the user under examination.

  In the above embodiment, the processor device 11 and the light source device 12 are separated, but they may be integrated. In the above embodiment, the living body observation endoscope has been described as an example. However, the present invention can also be applied to an industrial endoscope.

It is a figure which shows schematic structure of an endoscope system. It is a block diagram which shows the structure of an endoscope system. It is sectional drawing of a light guide. It is the schematic which shows the structure of an optical fiber bundle. It is an equivalent circuit diagram of a constant voltage source, an ammeter, and a conductive film. It is a graph which shows the relationship between resistance value and electric current value. It is a graph which shows the relationship between a resistance value and a voltage value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Endoscope system 10 Electronic endoscope 11 Processor apparatus 12 Light source apparatus 13 Insertion part 35 Light guide 55 Constant voltage source 56 Ammeter 57 Comparison circuit 59 Alarm device 60 CPU
65 Optical fiber 67 Conductive film

Claims (8)

A conductive film that individually covers a plurality of optical fibers constituting a light guide for guiding light inserted through an endoscope; and
Power supply means for supplying a predetermined level of power to the conductive film;
Based on a change in power applied to the plurality of optical fibers covered with the conductive film, determination means for determining a breakage state of the optical fiber;
An endoscope system comprising:   The endoscope system according to claim 1, wherein the conductive film is applied or sputtered on an outer peripheral surface of the optical fiber.   The endoscope system according to claim 1, wherein the conductive film is made of conductive resin, copper, or indium tin oxide. The power supply means is a constant voltage source that applies a constant voltage to the conductive film,
The said determination means has an ammeter which measures the electric current which flows through the said electrically conductive film, and a comparison circuit which compares the measured value of the said ammeter with a reference value, The inside of Claim 1 thru | or 3 characterized by the above-mentioned. Endoscopic system.   The endoscope system according to claim 4, further comprising storage means for storing the reference value.   6. The endoscope system according to claim 1, wherein the determination unit further determines whether or not the light guide can withstand use based on a determination result of a breakage state.   The endoscope system according to claim 1, further comprising a display unit that displays a determination result of the determination unit. A predetermined level of power is supplied to a conductive film that individually covers a plurality of optical fibers constituting a light guide for light guiding inserted through an endoscope,
An optical fiber breakage detection method, comprising: determining a breakage state of the optical fiber based on a change in electric power applied to the plurality of optical fibers covered with the conductive film.

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