JP4459724B2 - Endoscope light source device - Google Patents

Description

  The present invention relates to an endoscope light source device for selectively introducing illumination light for normal observation and laser light for fluorescence excitation into a light guide in an endoscope.

  As is well known, biological tissue is excited to emit fluorescence when irradiated with light of a specific wavelength. In addition, an abnormal living tissue in which a lesion such as a tumor or cancer has occurred emits weaker fluorescence than a normal living tissue. This reaction phenomenon can also be caused by living tissue below the body cavity wall. In recent years, endoscope systems have been developed that detect abnormalities occurring in a living tissue under a body cavity wall using this reaction phenomenon.

  As one of this type of endoscope system, a body cavity is illuminated by emitting illumination light in the visible band from the distal end of the endoscope, and an image of reflected light from the inner wall surface of the body cavity is captured by an imaging device. In addition to the observation mode, light of a specific wavelength band that excites the living tissue is emitted from the tip of the endoscope, and an image of fluorescence emitted from the living tissue under the inner wall of the body cavity excited by this light is captured by the imaging device There are endoscope systems that operate in the fluorescence observation mode.

  A light source device used for such an endoscope system includes an optical path of illumination light (white light) emitted from a visible light source together with a visible light source (for example, a halogen lamp) and a laser light source (for example, a semiconductor laser). And an optical path synthesizing element (half mirror, dichroic mirror, quick return mirror, etc.) for synthesizing the optical path of laser light emitted from a laser light source (light having a specific wavelength in a blue to ultraviolet band). The light source device emits illumination light emitted from a visible light source in a normal observation mode to a light guide guide fiber bundle of an endoscope inserted into a socket provided on the front surface, and a laser light source in a fluorescence observation mode. The laser beams emitted from are respectively introduced through optical path synthesis elements.

  The illumination light or laser light thus introduced into the light guide fiber bundle is transmitted by the light guide fiber bundle from the light guide flexible tube of the endoscope through the operation portion to the inside of the body cavity insertion portion. It is injected from the tip of the inner insertion part. Therefore, when this body cavity insertion part is inserted into the body cavity of the subject, in the normal observation mode, the reflected light from the body cavity inner wall irradiated with the illumination light emitted from the distal end of the body cavity insertion part The image of the inner wall of the body cavity by the imaging device (the objective optical system and imaging element incorporated in the distal end of the body cavity insertion portion, or the objective optical system incorporated in the body cavity insertion portion, the image formed by this objective optical system In the fluorescence observation mode, the image guide fiber bundle drawn through the body cavity insertion portion for transmission and a TV camera that captures an image transmitted by the image guide fiber bundle) An image by fluorescence emitted from a living tissue under the inner wall of the body cavity excited by laser light emitted from the tip is captured by the imaging device.

Each image data obtained by imaging in these two modes is processed by an image processor incorporated in the light source device or a separate image processing device. In the normal observation mode, image data for displaying a color image with visible light on the inner wall of the body cavity is generated, and the color image of the inner wall of the body cavity is displayed on the monitor based on the image data. On the other hand, in the fluorescence observation mode, image data for displaying the affected part in a specific color is generated, and a fluorescence image is displayed on the monitor based on the image data. By comparing these images, a doctor who is an operator of the endoscope can confirm the position and state of the affected part, and can perform various medical procedures for biopsy and treatment.
JP 07-005333 A JP-A-10-142449 JP 2002-071539 A

  However, in the conventional light source device for fluorescence observation, although the laser light source movable mechanism by the key switch is provided, the laser light leaks from the optical path from the laser light source to the light guide bundle of the endoscope through the optical path synthesis element. Was not considered. Therefore, even if there is no problem when the optical system is functioning as designed, the form of the optical system is no longer as designed because part of the optical system is damaged, tilted or dropped. In some cases, the laser beam may deviate from the designed optical path and become stray light.

  Such stray light is a laser beam with energy that is never low, so for example, when it leaks out from the housing of the light source device and enters the eyes of a medical staff such as a subject or a doctor, its visual function is affected. There was a possibility of causing problems such as causing troubles to some extent. In addition, when the laser beam deviates from the designed optical path, the amount of laser beam incident on the light guide bundle of the endoscope is reduced, so that the laser beam irradiated to the living tissue is insufficient and fluorescent light is emitted. This causes a problem that the amount of light decreases.

  The present invention has been made in view of such problems, and the problem is that an obstacle on the optical path from the laser light source to the light guide bundle is detected inside the light source device, and the output of the laser light is immediately stopped. It is an object to provide an endoscope light source device.

  An endoscope light source device invented to solve the above problems introduces a laser beam having a wavelength that excites a living tissue under a body cavity wall to emit fluorescence into a light guide fiber bundle of the endoscope. An endoscope light source device, wherein a socket into which a proximal end of the light guide fiber bundle is inserted, a laser light source for emitting the laser light, and the light guide fiber into which the laser light is inserted into the socket In the optical path between the laser beam optical system guided toward the end surface of the bundle, the photometric means for measuring the amount of the laser beam, and the end surface of the light guide fiber bundle inserted into the socket In contrast, a drive mechanism for selectively inserting the photometric means, a photometric result obtained by the photometric means being inputted, and the laser light source and the Control means for controlling a moving mechanism, wherein the control means causes the laser light source to emit a standard amount of laser light while the drive mechanism is inserting the photometric means into the optical path, and at this time, When the light quantity measured by the photometry means is lower than a threshold value corresponding to the standard light quantity, the laser light emission from the laser light source is stopped.

  If comprised in this way, a control means will be with respect to the optical path of the laser beam between a laser light source and this light guide fiber bundle prior to introducing a laser beam into the light guide fiber bundle of an endoscope. The photometric means is inserted by the drive mechanism, and a standard amount of laser light is emitted from the laser light source. At this time, if there is no failure in the laser light optical system between the laser light source and the photometric means, most of the light quantity reaches the insertion position of the photometric means except for the loss due to the optical surface and medium of each optical member constituting the optical system. Therefore, the amount of light measured by the light metering means should be a predetermined amount of light that is uniquely determined with respect to the standard light amount. On the other hand, if there is any failure in the laser light optical system between the laser light source and the photometry means, the laser light is reflected, refracted or scattered at this failure location, and reaches the insertion position of the photometry means. The laser beam to be attenuated greatly. For this reason, the amount of light measured by the light metering means is significantly less than the predetermined amount of light that is uniquely determined with respect to the standard light amount. Therefore, the control circuit compares the photometric result obtained by the photometric means with a predetermined threshold corresponding to the standard light quantity, and if the former is less than the latter, there is a high possibility that the laser beam optical system has failed. Therefore, the laser light emission from the laser light source is immediately stopped. As a result, the problem of leakage of laser light due to continued emission of laser light when a failure occurs in the laser light optical system is solved.

  As described above, according to the endoscope light source device of the present invention, a fault on the optical path from the laser light source to the light guide bundle can be easily detected inside the light source device. Output can be stopped.

  Next, modes for carrying out the present invention will be described based on the attached drawings.

Embodiment 1

  FIG. 1 is an external view of an endoscope system including a light source device that is a first embodiment of an endoscope light source device according to the present invention. As shown in FIG. 1, the endoscope system includes a fluorescence observation endoscope 10, a light source device 20, and a monitor 60.

  The fluorescence observation endoscope 10 is obtained by adding a modification for fluorescence observation to a normal electronic endoscope, and is inserted into a body cavity. An operation portion 10b having an angle knob for bending the tip portion of the portion 10a, a light guide flexible tube 10c for connecting the operation portion 10b and the light source device 20, and the light guide flexible tube 10c. A connector 10d provided at the proximal end is provided.

  FIG. 2 is a schematic diagram showing an internal configuration of the endoscope system. As shown in FIG. 2, an illumination window and an imaging window in which the light distribution lens 11 and the objective lens 12 are fitted are formed on the distal end surface of the body cavity insertion portion 10a. In the body cavity insertion portion 10 a, the imaging element 13 that captures the image of the subject formed by the objective lens 12, the buffer circuit 15 for transmitting the output of the imaging element 13, and the objective lens 12 are emitted. A laser light cut filter 14 for removing a wavelength component corresponding to a laser beam for fluorescence excitation described later from the emitted light is incorporated. A signal cable 18 for transmitting an image signal output from the image sensor 13 and processed by the buffer circuit 15 is passed through the body cavity insertion portion 10a, the operation portion 10b, and the light guide flexible tube 10c, and is connected to the connector. It is connected to a plurality of connector pins 31a constituting an electrical connector 31 (see FIG. 3) formed on the end face of 10d. In parallel with the signal cable 18, a light guide fiber bundle 16 made of quartz fiber is passed through the body cavity insertion portion 10a, the operation portion 10b, and the light guide flexible tube 10c. The distal end of the light guide fiber bundle 16 faces the light distribution lens 11 in the distal end portion of the body cavity insertion portion 10a, and the proximal end thereof is in a metal pipe 19 (see FIG. 3) protruding from the end face of the connector 10d. It is inserted and fixed.

  Further, a ROM (Read Only Memory) 17 storing identification information indicating the attributes of the endoscope is stored in the connector 10d. Each terminal of the ROM 17 is also connected to a circuit board (not shown). The signal connector 31 is connected to a plurality of other connector pins 31b via wiring. Since the endoscope described in this embodiment is the fluorescence observation endoscope 10, the ROM 17 stores identification information indicating that the endoscope is the fluorescence observation endoscope 10.

  Note that a normal electronic endoscope that can be used in exchange for the fluorescence observation endoscope 10 is not provided with a laser light cut filter 14 in that the optical fiber constituting the light guide fiber bundle 16 is not a quartz fiber. On the other hand, the fluorescence observation endoscope 10 has the same configuration except that the identification information stored in the ROM 17 indicates a normal electronic endoscope.

  The light source device 20 selectively introduces illumination light (white light) or laser light into the end face of the light guide fiber bundle 16 of the fluorescence observation endoscope 10 and also uses a buffer circuit through the connector pin 31a of the fluorescence observation endoscope 10. 15 is a device that generates a video signal by performing image processing on the image signal received from 15, and outputs it to the monitor 60. A specific configuration of the light source device 20 will be described in more detail with reference to FIGS. 1 and 2.

  As shown in FIGS. 1 and 2, a pipe 19 of an endoscope (fluorescence observation endoscope 10 or electronic endoscope) is inserted into the front panel of the casing of the light source device 20 from the outer surface side. A socket 20a, which is a cylinder, is provided. Inside the socket 20a, about 3/2 on the back side is enlarged in the radial direction, and a partition wall 24 is installed just in the middle position. A through hole is formed at the center of the partition wall 24. When the pipe 19 is inserted into the socket 20a, the through hole is pushed open by the pipe 19 itself, and the pipe 19 is pulled out from the socket 20a. In this case, it is closed by a lid-shaped shielding plate 24a that is restored by a restoring spring (not shown). When the shielding plate 24a is closed, the partition wall 24 can shield light leakage from the back of the socket 20a to the outside.

  Further, a pressing member 25 made of an annular plate is held at the innermost part of the socket 20a so as to be displaceable only in the axial direction (that is, the direction in which the pipe 19 is inserted and pulled out). . The hole formed in the center of the pressing member 25 has a taper shape that has substantially the same inner diameter as the pipe 19 and expands toward the back side. The pressing member 25 is urged outward by a plurality of compression springs 26 and is in a position close to the partition wall 24 when the pipe 19 is pulled out. When the pipe 19 is inserted into the socket 20a, the pipe 19 is pushed by the tip of the pipe 19 to move to the position shown in FIG. In this way, when the pressing member 25 finishes moving by being pushed by the pipe 19, at this position, the pressing member 25 is detected by a detection sensor (magnetic sensor, microswitch, etc.) attached to the inner wall of the socket 20a. And so on).

  The innermost wall of the socket 20 a is cut out except for the portion that supports the compression spring 26, and communicates with the internal space of the light source device 20. In the inner space of the light source device 20, the first rotary shutter 27 and the collector are arranged in order along the extension line of the central axis of the pipe 19 inserted into the socket 20 a (that is, the central axis of the light guide fiber bundle 16). An optical lens 28, a half mirror 29, a second rotary shutter 32, and a lamp 33 are disposed.

  The condensing lens 28 is a lens that condenses the parallel light incident from the half mirror 29 side along the optical axis onto the base end surface of the light guide fiber bundle 16 accommodated in the pipe 19.

  The first rotary shutter 27 and the second rotary shutter 32 are both discs having the same diameter, and are coaxial with each other and with respect to the central axis of the pipe 19 by a single shaft 35 that is rotationally driven by a motor 34. Offset and hold.

  FIG. 4 is a diagram showing a state in which the first rotary shutter 27 is viewed from the lamp 33 side. As shown in this figure, the first rotary shutter 27 has a fan-shaped (3/4 annular) opening 27a having a central angle of 270 degrees. As the first rotary shutter 27 rotates, the center of the first rotary shutter 27 (and hence the shaft 35) is such that the optical axis of the condenser lens 28 passes through the center of the opening 27a in the radial direction. It is positioned. In addition, in the fan-shaped (1/4 ring) region having a central angle of 90 degrees left by the formation of the opening 27a, a relative passage locus of the extension line of the pipe 19 accompanying the rotation of the first rotary shutter 27 is provided. A light receiving sensor 27b is attached at the center along the line. A weight (not shown) as a balancer is attached to the edge of the first rotary shutter 27 on the opening 27a side so that the center of gravity offset by the opening 27a and the light receiving sensor 27b matches the rotation center. The light receiving sensor 27b corresponds to a photometric unit, and the first rotary shutter 27, the shaft 35, and the motor 34 correspond to a driving mechanism.

  FIG. 5 is a diagram illustrating a state in which the second rotary shutter 32 is viewed from the lamp 33 side. As shown in this figure, the second rotary shutter 32 is provided with a fan-shaped (1/2 annular) opening 32a having a central angle of 180 degrees. As the first rotary shutter 32a rotates, the optical axis of the condenser lens 28 passes through the center of the opening 32a in the radial direction. In addition, a weight (not shown) as a balancer is attached to the edge of the second rotary shutter 32 on the opening 32a side so that the center of gravity offset by the opening 32a matches the rotation center. The first rotary shutter 27 and the second rotary shutter 32 are arranged so that the counterclockwise ends of the respective openings 27a and 32a coincide with each other when viewed from the lamp 33 side (that is, relative positions shown in FIGS. 4 and 5). Are connected to each other by a shaft 35. The shutters 27 and 32 are driven to rotate clockwise by the motor 34 when viewed from the lamp 33 side.

  A brush fixing disk 36 is coaxially fixed to the shaft 35, and an annular brush receiver 37 with the shaft 35 passing through the through hole is fixed to a frame (not shown) of the light source device 20. Yes. A pair of inner and outer brushes (not shown) connected to the electrodes of the light receiving sensor 27 b are fixed to the surface of the brush receiving disk 36 on the brush receiver 37 side, while the brush fixing disk 36 in the brush receiver 37 is fixed. On the side surface, concentric double circular electrodes (not shown) are formed which respectively match the rotation trajectory of each brush tip accompanying the rotation of the brush fixing disk 36 and contact the tip of each brush. Yes.

  The lamp 33 includes a light bulb (not shown) that emits white light when a power supply current is supplied from the lamp power supply 38, and a lens or reflector (not shown) that converts the white light emitted from the light bulb into parallel light. I have. As a result, the lamp 33 emits white light as parallel light along the optical axis of the condenser lens 28 through the half mirror 29 toward the condenser lens 28. This lamp 33 corresponds to a visible light source.

  The half mirror 29 is disposed with an inclination of 45 degrees with respect to the optical axis of the condenser lens 28. Therefore, the half mirror 29 transmits white light from the lamp 33 and reflects light from a direction perpendicular to the optical axis of the condenser lens 28 along the optical axis of the condenser lens 28. The light enters the condenser lens 28. A collimator lens 39 and a laser light source 40 are arranged in order on the optical axis of the condenser lens 28 bent 90 degrees by the half mirror 29. The half mirror corresponds to an optical path combining element that combines an optical path of white light emitted from the lamp 33 and an optical path of laser light emitted from a laser light source 40 described later.

  The laser light source 40 is a semiconductor laser that emits laser light in a wavelength band (ultraviolet to blue) that functions as excitation light as divergent light. The collimator lens 39 is a lens that converts laser light emitted from the laser light source 40 into parallel light. The collimator lens 39, the half mirror 29, and the condenser lens 28 correspond to a laser beam optical system.

  The half mirror 29 and the collimator lens 39 are covered with a bottomed cylindrical laser light source case 41. Specifically, the laser light source case 41 has a shape of a bottomed cylinder or a bottomed rectangular tube, and an opening end thereof is in close contact with a side surface of the laser light emission port in the casing of the laser light source 40 main body. Yes. The collimator lens 39 is fixed so as to be integrated within the laser light source case 41 so as not to form a gap with the inner surface of the laser light source case 41. Further, a half mirror 29 is fixed near the closed end inside the laser light source case 41. Therefore, the laser light source case 41 occupies a position between the condenser lens 28 and the second rotary shutter 32. The wall surface of the laser light source case 41 is cut out at two locations so that an opening that is slightly larger than the optical path of the white light is formed along the optical path of the white light emitted from the lamp 33. Therefore, the laser light emitted from the laser light source 40 is shielded by the inner surface of the laser light source case 41 even if the collimator lens 39 is off the original optical path due to tilting or dropping off. It will not leak outside. A part of the laser light passes through the half mirror. However, since the closed end of the laser light source case 41 exists at the end of the laser beam, the laser light does not leak outside the laser light source case 41. However, in order to prevent the laser light hitting the closed end from being reflected and becoming stray light, it is desirable that the inner surface of the laser light source case 41 is subjected to antireflection treatment.

  With the above optical configuration, the white light emitted from the lamp 33 passes through the second rotary shutter 32 only during the period in which the opening 32a of the second rotary shutter 32 is positioned on the optical axis of the condenser lens 28, and Then, the light passes through the half mirror 29 and the condenser lens 28. At this time, since the opening 27 a of the first rotary shutter 27 is always located on the optical axis of the condenser lens 28, the white light passes through the first rotary shutter 27 and enters the light guide fiber bundle 16. On the other hand, the laser light source 40 controlled by a system control circuit 42 to be described later emits laser light only during a period in which the second rotary shutter 32 blocks white light. The laser light is collimated by the collimator lens 39, reflected by the half mirror 29, and transmitted through the condenser lens 28. At this time, a portion where the opening 27a of the first rotary shutter 27 is not formed is first positioned on the optical axis of the condenser lens 28, and then the opening 27a is positioned. Accordingly, the laser light first enters the light receiving sensor 27b, and then passes through the opening 27a and enters the light guide fiber bundle 16.

  On the other hand, on the front panel of the housing of the light source device 20, an electrical socket 21 made up of a number of electrodes each conducting with the connector pins 31a, 31b constituting the electrical connector 31 in a state where the pipe 19 is inserted into the socket 20a. And a key switch 22 that is an electric switch whose circuit is opened and closed only by a key that can be inserted from the outside, and a plurality of switches that are operated from the outside (only the mode switch 23a and the laser switch 23b are shown in FIG. 2). An operation panel 23 is provided. The key switch 22 is connected in the middle of a circuit that supplies a drive current to the laser light source 40 from a main power supply device (not shown). Therefore, the laser light source 40 does not emit laser light unless the key switch 22 is inserted from the outside and closed.

  The electrodes constituting the electrical socket 21 connected to the ROM 17 and the switches 23a and 23b on the operation panel 23 are respectively connected to a system control circuit 42 serving as a control means. As a result, the data of the identification information in the ROM 17 is input to the system control circuit 42 through the connector pin 31b and the electrical socket 21. Similarly, operation signals generated by operations on the switches 23 a and 23 b on the operation panel 23 are respectively input to the system control circuit 42. Of the electrodes constituting the electrical socket 21, the electrode connected to the buffer circuit 15 is connected to the video signal processing circuit 43. As a result, the image signal output from the image sensor 13 through the buffer circuit 15 is input to the video signal processing circuit 43 through the connector pin 31 a and the electrical socket 21.

  The detection sensor 30 described above is also connected to the system control circuit 42, and a signal for detecting that the pipe 19 of the endoscope 10 has been inserted to the most position (ie, pushed by the tip of the pipe 19). The detection signal generated by the detection sensor 30 when the pressing member 25 is detected is input. Further, the system control circuit 42 receives the output signal of the light receiving sensor 27b (that is, the light incident on the light receiving sensor 27b) via each brush on the brush fixing plate 36 and each circular electrode on the brush receiver 37. The signal indicating the amount of light) is input. Further, the system control circuit 42 is connected to the motor 34, the lamp power supply 38 and the laser light source 40 described above, and outputs signals for controlling them.

  The system control circuit 42 is connected to the video signal processing circuit 43, and exchanges signals with the video signal processing circuit 43. Hereinafter, functions of the system control circuit 42 and the video signal processing circuit 43 will be described.

  The system control circuit 42 is in a period during which a detection signal is input by the detection sensor 30 (that is, a period in which the connector 10d of the endoscope 10 is attached to the light source device 20 and its pipe 19 is inserted into the socket 10a). Only the lamp power supply 38, the laser light source 40, and the video signal processing circuit 43 can be activated. Then, the system control circuit 42 determines whether the mounted endoscope 10 is a normal endoscope or a fluorescence observation endoscope based on the identification information read from the ROM 17 in the connector 10d. . If the mounted endoscope 10 is a normal endoscope, the operation mode is fixed to the normal observation mode, and if the mounted endoscope is a fluorescence observation endoscope, the mode is switched. Each time the switch 23a is pressed, the operation mode is switched between the normal observation mode and the fluorescence observation mode. On the other hand, the video signal processing circuit 43 receives a signal from the system control circuit 42, and is output from the image sensor 13 through the buffer circuit 15 only while the socket 10 a of the endoscope 10 is attached to the light source device 20. Process the image signal.

  Then, the system control circuit 42 activates the lamp power supply 38 to emit white light from the lamp 33 and uses a timing signal (vertical synchronization signal indicating the start timing of each frame) generated in the lamp 34 to the motor 34. 6b, white light emitted from the lamp 33 is emitted from the lamp 33 only during the period corresponding to the odd-numbered frame, as shown in FIG. 6B, and the opening 27a of the second rotary shutter 27 and the opening 27a of the first rotary shutter 27. The rotation of the motor 34 is controlled so that it passes through the light guide fiber bundle 16 and enters the light guide fiber bundle 16. Note that the system control circuit 42 does not depend on the operation mode, and immediately after the detection sensor 30 detects that the pipe 19 of the endoscope 10 has been inserted to the most extent, the laser light source 40 is input. Does not start.

  On the other hand, regardless of the operation mode, the video signal processing circuit 43, during the period corresponding to each odd-numbered frame, according to the timing signal received from the system control circuit 42, as shown in FIG. The received image signal is processed as an image signal of a visible image obtained by reflected light of white light, and the image signal received during a period corresponding to an even-numbered frame is used as an image signal of a fluorescent image obtained by laser light. Process. Then, the video signal processing circuit 43 inputs the level (average luminance value) of the image signal in each frame to the system control circuit 42.

  At this time, as shown in FIG. 6C, if the difference between the level of the image signal in the odd-numbered frame and the level of the image signal in the even-numbered frame is equal to or less than a predetermined reference value Δv, the system control circuit 42 It is determined that external light is incident on the image sensor 13 (that is, the intracorporeal insertion portion 10a of the endoscope 10 has not yet been inserted into the body cavity of the subject), and depends on the operation mode. First, the laser light source 40 is kept stopped. On the other hand, when the difference exceeds the predetermined reference value Δv, the system control circuit 42 has no external light incident on the image sensor 13 (that is, the body cavity insertion portion 10a of the endoscope 10 is subject to the subject). If the operation mode is the fluorescence observation mode and the laser switch 23b is pressed, the stop of the laser light source 40 is released. Note that the level of the image signal of the fluorescent image is much lower than that of the visible image. Therefore, even after this, the system control circuit 42 is in the fluorescence observation mode if the difference between the level of the image signal in the odd-numbered frame and the level of the image signal in the even-numbered frame is equal to or less than the predetermined reference value Δv. However, when the laser light source 40 is stopped and the difference exceeds the predetermined reference value Δv, the stop of the laser light source 40 is canceled on the condition that the mode is the fluorescence observation mode and the laser switch 23b is pressed.

  Specifically, while the stop of the laser light source 40 is released, the system control circuit 42 is a timing at which the light receiving sensor 27b reaches the optical path from the condenser lens 28 as shown in FIG. First (within the period of the first field in each even-numbered frame), first, the laser light source 40 is caused to emit light with an allowable maximum light amount (standard light amount). At this time, if the level of the image signal input from the video signal processing circuit 43 is below a predetermined threshold corresponding to the light quantity, the system control circuit 42 is in the middle of the optical path from the laser light source 40 to the first rotary shutter 27. When it is determined that some kind of failure has occurred, the laser light source 40 is immediately stopped. In contrast, if the level of the image signal input from the video signal processing circuit 43 is equal to or higher than a predetermined threshold corresponding to the light amount, the system control circuit 42 is on the optical path from the laser light source 40 to the first rotary shutter 27. In the period until the end of the same frame, the luminance level of the image signal input from the video signal processing circuit 43 is set to a target value for automatic light control that is lower than the predetermined threshold. The amount of light emitted from the laser light source 40 is automatically adjusted so as to approximately match. As a result, image data obtained by capturing an image by fluorescence is input to the video signal processing circuit 43 within the period of the second field in each even-numbered frame.

  In the normal observation mode, the video signal processing circuit 43 generates color image data by processing the image signals of all fields in odd-numbered frames, and displays a visible image based on the color image data on the monitor 60. . On the other hand, in the fluorescence observation mode, the video signal processing circuit 43 compares the luminance distribution component in the image signal of the odd-numbered frame with the luminance component of the image signal of the second field in the even-numbered frame, and the ratio between them. A portion where is equal to or greater than a certain value is identified as a lesion, fluorescence observation image data in which the identified lesion is superimposed on color image data is generated, and a fluorescence observation image based on this fluorescence observation image data is displayed on the monitor 60 .

  As described above, according to the endoscope system of the present embodiment, the identification information data in the ROM 17 is not input to the system control circuit 42 while no endoscope is attached to the light source device 20. In addition, since the output of the detection sensor 30 is not input to the system control circuit 42, the system control circuit 42 does not activate the laser light source 40. Therefore, laser light is not emitted from the laser light source 40. Even if a laser beam is emitted from the laser light source 40 due to some failure, the laser beam does not leak to the outside of the laser light source case 41, and the laser beam reflected by the half mirror 29 is separated from the partition wall. 24 and the shielding plate 24a. Therefore, in any case, the laser light does not leak to the outside of the light source device 2.

  On the other hand, when a normal endoscope is mounted on the light source device 20, the pressing member 25 into which the tip of the pipe 19 of the connector 10d has been pressed is detected by the detection sensor 30, and the detection signal is a system control circuit 42. Is input. However, since only the identification information indicating that the endoscope is a normal endoscope is stored in the ROM 17 in the connector 10d of the attached endoscope, the system control circuit 42 does not include the laser light source 40. Never start. Therefore, the laser beam is not emitted from the distal end surface of the body cavity insertion portion of the endoscope against the will of the operator.

  Next, when the fluorescence observation endoscope 10 is attached to the light source device 20, the detection signal output from the detection sensor 30 as described above is input to the system control circuit 42 and the ROM 17 in the connector 10d. The identification information (identification information indicating that the endoscope is a fluorescence observation endoscope) read out from is input to the system control circuit 42. Therefore, when the mode switch 23a is pressed, the operation mode of the system control circuit 42 is switched to the fluorescence observation mode. Further, when the laser switch 23b is pressed, the system control circuit 42 can operate in the fluorescence observation mode. Become.

  Therefore, the system control circuit 42 first causes the motor 34 to rotate the first rotary shutter 27 and the second rotary shutter and emit white light from the lamp 34 without starting the laser light source 40. As a result, the image signal of the odd-numbered frame obtained during the period when the white light is incident on the light guide fiber bundle 16 from the buffer circuit 15 of the image sensor 13 and the white light are transmitted to the system control circuit 42. The image signals of even-numbered frames obtained during a period when the light is not incident on the guide fiber bundle 16 are alternately incident. At this time, if the body cavity insertion portion 10a of the fluorescence observation endoscope 10 is outside the body cavity of the subject, the light emitted from the light distribution window 11 does not contribute much to the level of the image signal. There is not much difference between the level of the image signal of the current frame and the level of the image signal of the even-numbered frame. Therefore, the system control circuit 42 keeps the laser light source 40 stopped. When the body cavity insertion portion 10a of the fluorescence observation endoscope 10 is inserted into the body cavity of the subject, the level of the image signal of the odd-numbered frame depends on the white light emitted from the light distribution window 11. Thus, the level of the image signal of the even-numbered frame is the lowest level as long as no light is emitted from the light distribution window 11. Therefore, since the level difference between the two image signals becomes large, the system control circuit 42 activates the laser light source. As a result, laser light is emitted from the light distribution window 11 and fluorescence is emitted from the living tissue below the inner wall of the body cavity, but the level of this fluorescence is much smaller than the level of the reflected light of the white light. The level difference remains large. Therefore, the system control circuit 42 continues to activate the laser light source 40. The laser light emitted from the laser light source 40 activated in this way does not leak outside the laser light source case 41. Even if the collimator lens 39 and the half mirror 29 in the laser light source case 41 are displaced or dropped, the laser light source case 41 blocks the light and the laser light does not leak outside.

  Further, in the fluorescence observation mode, the system control circuit 42 emits a laser beam with a predetermined maximum output value from the laser light source 40 within the period of the first field of each even-numbered frame, and at this time, the condenser lens The output of the laser beam emitted from 28 is measured by the light receiving sensor 27b. If the measured value is equal to or less than the predetermined threshold value, it is determined that some failure has occurred on the optical path from the laser light source 40 to the condenser lens 28, and the laser light source 40 is immediately stopped. On the other hand, if the measured value exceeds the predetermined threshold value, it is determined that there is no abnormality on the optical path, and laser light is emitted from the laser light source 40 with an appropriate amount of light in the subsequent second field. As a result, when a failure has occurred on the optical path from the laser light source 40 to the condenser lens 28, the laser light source 40 is stopped, so that the laser light is prevented from leaking from the failure location. However, if the failure location is on the optical path from the laser light source 40 to the half mirror 29, the laser light source case 41 prevents leakage of the laser light.

  As described above, according to the endoscope system of the present embodiment, except when the fluorescent endoscope 10 is emitted from the light distribution lens 11 of the body cavity insertion portion 10a when connected to the light source device 2. Laser light is prevented from leaking outside the endoscope system. Therefore, it is possible to prevent accidents due to unintended leakage of laser light.

Embodiment 2

  FIG. 8 is a cross-sectional view showing a structure of a laser light source case 141 used in the light source device 20 according to the second embodiment of the present invention. As shown in FIG. 8, the structure of the laser light source case 141 has the same shape as the laser light source case 41 of the first embodiment, and has an opening for allowing white light from the lamp 33 toward the half mirror 29 to pass therethrough. The laser light cut filter 142 is closed. FIG. 9 is a graph showing the transmission characteristics of the laser light cut filter 142, where the horizontal axis represents wavelength and the vertical axis represents transmitted light intensity. In FIG. 9, α indicates the spectral characteristic of laser light, and β indicates the transmission characteristic of the laser light cut filter 142.

  According to the second embodiment, even when a failure occurs in the laser light source 40, the collimator lens 39, or the half mirror 29, one of the openings (opening on the lamp 33 side) through which the laser light can leak to the outside is the laser light cut filter. Therefore, the possibility that the laser light leaks outside the laser light source case 141 is reduced as compared with the first embodiment.

  Other configurations and operations in the second embodiment are exactly the same as those in the first embodiment, and thus description thereof is omitted.

Embodiment 3

  FIG. 10 is a sectional view showing a structure of a laser light source case 241 used in the light source device 20 according to the third embodiment of the present invention. As shown in FIG. 10, the laser light source case 241 has substantially the same shape as that of the laser light source case 41 of the first embodiment, but is controlled by the system control circuit 42 inside thereof. An inner cylinder 242 is inserted so as to be movable in the axial direction by the motor 244. The inner cylinder 242 has a bottomed cylindrical shape with the open end facing the collimator lens 39, and the outer diameter thereof is slightly smaller than the inner diameter of the laser light source case 241. Therefore, although the inner cylinder 242 can move within the laser light source case 241, the laser light does not leak from the gap between them. In addition, a mirror 243 is fixed in the inner cylinder 242 in such a positional relationship that the optical axis of the condenser lens 28 intersects the center thereof at an angle of 45 ° when moved to the position farthest from the collimator lens 39. Has been. Further, the side wall of the inner cylinder 242 closer to the condenser lens 28 overlaps the opening of the laser light source case 241 on the condenser lens 28 side when the inner cylinder 242 moves to the position farthest from the collimator lens 39. An opening is drilled.

  In the fluorescence observation mode, the third embodiment is suitable for a configuration in which only the laser light is irradiated without irradiating the inner wall of the body cavity with white light, and the lesion is determined only from the image formed by the fluorescence. Therefore, in the fluorescence observation mode, the mirror 243 is disposed at the position shown in FIG. In this state, even if the laser light source 40, the collimator lens 39, or the mirror 243 has a failure, one of the openings (opening on the lamp 33 side) through which the laser light can leak to the outside is close to the lamp 33 of the inner cylinder 242. Since it is covered with the side wall on the side, the possibility that the laser light leaks to the outside of the laser light source case 241 is reduced by half compared to the first embodiment. On the other hand, in the normal observation mode, the inner cylinder 242 moves together with the mirror 243 toward the collimator lens 39, and retracts from the white light path so that the white light enters the condenser lens 28. In this state, even if the laser light is emitted from the laser light source 40 due to some failure, the laser light is completely shielded by the inner cylinder 242 and therefore does not leak outside the laser light source case 241.

  Other configurations and operations in the third embodiment are exactly the same as those in the first embodiment, and thus description thereof is omitted.

Embodiment 4

  FIG. 11 is an optical configuration diagram showing only the main configuration of the light source device 20 according to the fourth embodiment of the present invention. As shown in FIG. 11, in the fourth embodiment, as compared with the first embodiment described above, instead of the first rotary shutter 27, it is selectively inserted into the optical path by being rotated by a motor 45. A blade-type shutter 44 is provided. A light receiving sensor 46 corresponding to the light receiving sensor 27b in the first embodiment is attached to the surface of the blade-type shutter 44 on the condenser lens 28 side. The output of the light receiving sensor 46 is input to the system control circuit 42 via a signal line (not shown). However, the blade-type shutter 44 cannot be inserted into the optical path at the same speed as the first rotary shutter 27 in the first embodiment because of its structure. Therefore, in the third embodiment, the system control circuit 42 enters the blade-type shutter 44 into the optical path of the laser light immediately after the operation mode is switched to the fluorescence observation mode and the laser light source 40 can emit light, for example. Then, the light quantity of the laser beam is measured by the light receiving sensor 46, the laser light source 40 is stopped if the photometric light quantity is lower than a predetermined threshold value, and if the photometric light quantity exceeds the predetermined threshold value, the laser Continue to emit laser light with an appropriate amount of light adjusted from the light source 40. The light receiving sensor 46 described above corresponds to the photometric means, and the blade-type shutter 44 and the motor 45 correspond to the driving mechanism.

1 is an external view showing an external appearance of an endoscope system according to a first embodiment of the present invention. Schematic showing the internal configuration of the endoscope system External view of fluorescence observation endoscope Front view of the first rotary shutter Front view of the second rotary shutter The graph which shows the principle which detects that the insertion part in a body cavity is inserted in the body cavity of a subject Graph showing laser light measurement and light intensity adjustment in fluorescence observation mode Sectional drawing which shows the laser light source case by 2nd Embodiment of this invention. Graph showing transmission characteristics of laser light cut filter Sectional drawing which shows the laser light source case by 3rd Embodiment of this invention. Sectional drawing which shows the laser light source case by 4th Embodiment of this invention.

Explanation of symbols

10 Fluorescence observation endoscope 16 Light guide fiber bundle 17 ROM
19 Pipe 20 Light source device 27 First rotary shutter 27b Light receiving sensor 28 Condensing lens 29 Half mirror 33 Lamp 39 Collimator lens 40 Laser light source 41 Laser light source case 42 System control circuit 43 Video signal processing circuit 60 Monitor

Claims (6)

An endoscope light source device for introducing a laser beam having a wavelength for exciting a living tissue under a body cavity wall to emit fluorescence into a light guide fiber bundle of an endoscope,
A socket into which the proximal end of the light guide fiber bundle is inserted;
A laser light source for emitting the laser light;
A laser beam optical system for guiding the laser beam toward an end surface of the light guide fiber bundle inserted into the socket;
A photometric means for measuring the amount of the laser beam;
A drive mechanism for selectively inserting the photometric means into an optical path between the laser beam optical system and an end face of the light guide fiber bundle inserted into the socket;
And a control means for controlling the laser light source and the drive mechanism while inputting a photometric result by the photometric means,
The control means emits a standard amount of laser light from the laser light source while the drive mechanism inserts the photometry means into the optical path, and the amount of light measured by the photometry means at this time is changed to the standard light quantity. An endoscope light source device that stops the emission of laser light from the laser light source if it is lower than a threshold corresponding to the amount of light. The threshold value corresponds to a light amount measured by the light metering means when a laser light having a standard light amount is emitted from the laser light source in a state where the laser light optical system is not damaged. The endoscope light source device according to 1. If the light quantity measured by the photometry means is equal to or greater than the threshold, the control means changes the light quantity of the laser light emitted from the laser light source to a light quantity suitable for emitting the fluorescence, 2. The endoscope light source device according to claim 1, wherein the photometric means is retracted from the optical path by the driving mechanism. 2. The endoscope light source device according to claim 1, wherein the photometric means is attached to a surface of a shutter that is selectively inserted into the optical path by the driving mechanism. The internal shutter according to claim 4, wherein the shutter is a rotary shutter that is formed of a disc having an opening through which a portion of the laser beam is transmitted in a circumferential direction, and is rotationally driven by the driving mechanism. Mirror light source device. While further comprising a white light source that emits white light as parallel light,
The laser beam optical system includes a collimator lens that collimates the laser beam emitted from the laser light source, reflects the laser beam transmitted through the collimator lens, and transmits the white light while transmitting the white light. And a condensing lens that condenses the laser light and white light on the end face of the light guide fiber bundle inserted into the socket. Item 5. The endoscope light source device according to Item 1.