JP4512422B2 - Endoscope objective optical system and fluorescence observation endoscope - Google Patents

Description

  The present invention relates to a fluorescence observation endoscope in which an image of an inner wall of a body cavity caused by fluorescence emitted from a living tissue under the inner wall of the body cavity by an excitation light introduced into the body cavity is picked up by an imaging device, and such a fluorescence observation endoscope The present invention relates to an endoscope objective optical system used in the above.

  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 has less fluorescence than a normal living tissue. In recent years, endoscope systems have been developed for detecting abnormalities occurring in living tissue under the body cavity wall by utilizing this reaction phenomenon.

As such an endoscope system, an image (normal image) of the inner wall of the body cavity formed by the illumination light reflected by the surface of the inner wall of the body cavity and the lower part of the body cavity wall with the distal end of the endoscope inserted into the body cavity A device capable of selectively capturing an image of the inner wall of a body cavity (fluorescent image) formed by fluorescence emitted from the living tissue is used in practice (see, for example, Patent Document 1). A light source device used in this type of endoscope system includes an excitation light transmission filter that extracts excitation light for exciting biological tissue from white light, and is in the optical path of white light emitted from the light source. By inserting or extracting the excitation light transmission filter, white light and excitation light as illumination light are selectively introduced into the light guide in the endoscope. However, in this type of endoscope system, in order to prevent the image inside the body cavity formed by the excitation light reflected by the surface of the body cavity wall when the excitation light is irradiated into the body cavity from being mixed with the fluorescence image, It is necessary to incorporate an excitation light cut filter for removing excitation light on the optical path from the objective optical system to the imaging apparatus. For example, in the endoscope system described in Patent Document 1, excitation light cut coating is applied to the lens surface of one lens included in the objective optical system.
JP 2002-153414 A

  Such an excitation light cut filter cuts light components in the wavelength band of the excitation light and shorter wavelength bands, so that white light is introduced into the light guide in the endoscope and a normal image is taken. Even in this case, the light component in the band in the reflected light on the surface of the body cavity wall is blocked. Even so, if the excitation light is in the ultraviolet region, the wavelength component blocked by the excitation light cut filter is in the ultraviolet region, and no visible light component is lost. There is no problem.

  However, when visible light near 400 to 450 nm, for example, is used as the excitation light, the wavelength component blocked by the excitation light cut filter is a visible light component, so that color reproducibility becomes a problem during normal image observation.

  As means for solving this problem, an imaging device for normal image observation for capturing a normal image while white light is introduced into the light guide in the endoscope, and an excitation light for the light guide in the endoscope Incorporating a fluorescence image observation image sensor for taking a fluorescent image while it is being introduced into the distal end of the body cavity insertion part of a single endoscope, between the objective optical system and the fluorescence image observation image sensor It is also conceivable to arrange the excitation light cut filter only on the optical path. However, in order to adopt this configuration, two imaging elements and corresponding complex optical systems are required in the distal end of the insertion part in the body cavity. Have difficulty.

  As another means for solving the above problem, a configuration in which only one image sensor is used and an excitation light cut filter is selectively inserted in the optical path between the objective optical system and the image sensor can be considered. However, in order to adopt this configuration, it is necessary to secure a space for retracting the excitation light cut filter to the side of the optical path in addition to the arrangement space of the drive mechanism of the excitation light cut filter. A dead space is increased inside the tip of the inner insertion portion, and its outer diameter is increased.

  Therefore, an object of the present invention is to provide a fluorescent image and a normal image with accurate color reproducibility with a single image sensor, but in addition to the installation space for the observation and drive mechanism, In addition, since it is not necessary to secure a retreat space for the excitation light cut filter, the fluorescence observation endoscope that can prevent the outer diameter of the insertion portion in the body cavity from being thickened, and the endoscope used for such an endoscope A scope objective optical system is provided.

  The endoscope objective optical system according to the present invention devised to solve the above problems is excited by an image of a subject by reflected light of white light introduced into a body cavity and excitation light introduced into the body cavity. Objective optical system for endoscope which is incorporated in the tip of a fluorescence observation endoscope for selectively capturing an image of a subject by fluorescence emitted from a living tissue, and forms each image on the imaging surface of an image sensor In addition, one or a plurality of lenses each having a refractive power and a rotation axis orthogonal to the optical axis of each lens are rotatably held, and a part of the surface thereof is provided with the rotation Excitation in which the entire object light toward the imaging surface of the image sensor is incident at the first rotation position due to movement, and is entirely retracted from the optical path of the subject light at the second rotation position due to rotation. Light cut coating And it is rotated optical element, characterized in that it contains.

  Similarly, the fluorescence observation endoscope according to the present invention devised to solve the above-described problems is based on the image of the subject by the reflected light of white light introduced into the body cavity and the excitation light introduced into the body cavity. A fluorescence observation endoscope for selectively capturing an image of a subject by fluorescence emitted from an excited biological tissue, an image sensor that captures an image formed on an imaging surface thereof, and imaging of the image sensor In order to form each of the images on the surface, the lens is held rotatably about one or more lenses each having refractive power, and a rotation axis orthogonal to the optical axis of each lens. The entire subject light toward the imaging surface of the imaging element is incident on a part of the surface at the first rotation position due to the rotation, and the subject light is incident at the second rotation position due to the rotation. Evacuate the whole from the light path An objective optical system including a rotating optical element excitation light cut coating is applied, characterized by comprising incorporating into the tip of the body cavity insertion portion of the elongate.

  With this configuration, at the time of fluorescence observation, all components of the subject light can be incident on the excitation light cut filter by rotating the rotation optical element to the first rotation position. In the normal observation, the entire excitation light cut filter can be obtained by rotating the rotating optical element to the second rotating position. Since the object light can be retracted outside the optical path, an image that accurately reproduces the actual color distribution of the object can be obtained. Moreover, since the excitation light cut coating is retracted from the subject light by the rotation of the rotating optical element, an installation space for the mechanism for rotating the rotating optical element is necessary, but the excitation light cut filter itself. There is no need for space to evacuate. Accordingly, it is possible to prevent the outer diameter of the distal end of the body cavity insertion portion from being increased accordingly.

  According to the fluorescence observation endoscope and the endoscope objective optical system of the present invention configured as described above, a single image pickup device can capture a fluorescent image and a normal image with accurate color reproducibility. In addition to the installation space for the observation and drive mechanism, it is not necessary to secure a retreat space for the excitation light cut filter on the side of the objective optical system. Therefore, according to the fluorescence observation endoscope according to the present invention and the endoscope incorporating the endoscope objective optical system according to the present invention, an increase in the outer diameter of the body cavity insertion portion can be suppressed.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram illustrating a configuration of an endoscope system according to an embodiment of the present invention. As shown in FIG. 1, the endoscope system includes a fluorescence observation endoscope 10, a light source processor device 20, and a monitor 30.

  FIG. 2 is an external view of the fluorescence observation endoscope 10 used in this endoscope system. As shown in FIG. 2, the fluorescence observation endoscope 10 has a flexible tubular body cavity insertion portion 10a to be inserted into the body cavity. A bending portion is incorporated at the distal end of the body cavity insertion portion 10a, and an operation portion 10b provided with an angle knob and various switches for operating the bending amount and the bending direction of the bending portion at the proximal end. It is connected. Further, the distal end of the light guide flexible tube 10c is connected to the side surface of the operation portion 10b, and the connector 10d is connected to the proximal end of the light guide flexible tube 10c.

  As shown in the schematic diagram of FIG. 1, three through holes are formed in the distal end surface of the body cavity insertion portion 10 a, and the light distribution lens 11 and the objective optical system 12 are provided in two of the through holes. Each is fitted. The light distribution lens 11 is composed of a single negative lens. The objective optical system 12 is an imaging optical system composed of a large number of lenses, and a specific configuration thereof will be described in detail later with reference to FIG. The remaining one through hole formed in the body cavity insertion portion 10a is used as the forceps port 13. A thin tube 14 connecting the forceps port 13 and the forceps port pierced in the operation portion is passed through the body cavity insertion portion 10a. The thin tube 14 functions as a forceps channel for inserting a treatment tool such as a forceps, a scissors, or a coagulation electrode.

  Further, the light guide 18 is passed through the body cavity insertion portion 10a. The light guide 18 is composed of a large number of flexible optical fibers, and the front end surface thereof faces the light distribution lens 11. Further, the base end of the light guide 18 is fixed in a metal pipe that is led through the operation portion 10b and the light guide flexible tube 10c and protrudes from the base end surface of the connector 10d.

  Furthermore, an imaging element (color CCD) 16 that captures an image of a subject formed by the objective optical system 12 on its imaging surface is incorporated in the body cavity insertion portion 10a. An optical filter 15 (see FIG. 3) is interposed between the elements 16.

  As shown in FIGS. 3A and 3B, the objective optical system 12 is an imaging optical system having four negative, positive, negative, and positive components in order from the object side, and the first to third lenses are provided. These are a plurality of lenses each having a refractive power, and the most image side lens is a ball lens 120 as a rotating optical element made of a perfect sphere. The ball lens 120 is supported by a drive motor 19 shown in FIG. 1 so as to be rotatable (spinning) around a rotation axis that is orthogonal to the optical axis of the entire objective optical system 12 and penetrates its center. The surface of the ball lens 120 is provided with an excitation light cut coating 120a centering on one point that intersects the optical axis of the entire objective optical system 12 during the rotation (spinning) by the drive motor 19. The excitation light cut coating 120a blocks light in the same wavelength band as the excitation light to be used (and the shorter wavelength side band) and transmits only light in the longer wavelength side band.

  The outer diameter of the excitation light cut coating 120 a is 90 ° when viewed from the center of the ball lens 120 in a cross section that includes the optical axis and is perpendicular to the rotation axis, and is larger than the effective diameter of the ball lens 120. It is set to be large enough. Therefore, when the center of the excitation light cut coating 120a is on the optical axis (that is, the first rotation position), it enters from the object side surface of the objective optical system 12 and enters the light receiving surface of the image sensor 16 described later. All the light fluxes (hereinafter referred to as “subject light”) enter the excitation light cut coating 120a. On the other hand, when the ball lens 120 is rotated by 90 ° from the state where the center of the excitation light cut coating 120a is on the optical axis (that is, the second rotation position), the entire excitation light cut coating 120a. Retracts out of the optical path of the subject light.

  A large number of switches 10g (only one is shown in FIG. 1) are provided on the outer surface of the operation unit 10b of the fluorescence observation endoscope 10. In addition, a driver 17 that is a circuit for driving the image sensor 16 and the drive motor 19 is incorporated in the connector 10d of the endoscope 10 in accordance with instructions from a system control unit 22 in the light source processor device 20 described later. .

Video signal imaging element 1 6 has output by taking an image is output through a signal cable 16b. The signal cable 16b is passed through the body cavity insertion portion 10a, the operation portion 10b, and the light guide flexible tube 10c, and is included among the many signal pins constituting the electrical connector 31 provided on the end surface of the connector 10d. Some are connected. In parallel with the signal cable 16b, a plurality of signal lines respectively connected to the respective switches 10g are routed through the operation unit 10b and the light guide flexible tube 10c to any one of the signal pins constituting the electrical connector 31. Each is connected. Similarly, a signal line for inputting a control signal from the system control unit 22 to the driver 17 is also connected to any signal pin constituting the electrical connector 31.

  The light source processor device 20 includes a light source block 24 that selectively introduces white light (light including all bands in the visible region) and excitation light to the end face of the light guide 18 of the fluorescence observation endoscope 10, and the fluorescence observation endoscope. The image processing unit 23 that generates a video signal by performing image processing on the video signal received from the image sensor 16 through the ten electrical connectors 31, and the light source block 24 and the image processing unit 23 are integratedly controlled. The system control unit 22 is the main component.

  A socket (not shown) into which the light guide 18 protruding from the connector 10 d of the fluorescence observation endoscope 10 is inserted is provided on the side surface of the housing of the light source processor device 20. A rotating filter 241, a condenser lens 243 and a white light source 245 constituting the light source block 24 are arranged on an extension line of the central axis of the light guide 18 inserted into the socket.

  The white light source 245 is controlled by the system control unit 22 and emits white light including at least light in the entire visible region and light in a band used as excitation light (visible light or ultraviolet light) to the optical axis of the condenser lens 243. (Ie, along the extension of the central axis of the light guide 18) along the axis of the light guide 18. The condensing lens 243 condenses the parallel light emitted from the white light source 245 along the optical axis on the base end surface of the light guide 18 inserted in the socket.

  The rotation filter 241 disposed between the light guide 18 inserted into the socket and the condenser lens 243 is rotated about the rotation axis by the filter motor 242 controlled by the system control unit 22. The rotary filter 241 is provided with a transmission part and an excitation light transmission filter that are concentric with the rotation center and have a central angle of 180 ° and are congruent to each other. This transmission part transmits all white light. On the other hand, the excitation light transmission filter transmits only light in a band used as excitation light from white light. The rotation filter 241 is disposed at a position where the transmission unit and the excitation light transmission filter alternately enter the optical path of white light as the rotation filter 241 rotates.

  The side surface of the housing of the light source processor device 20 is further provided with a large number of electrodes that are electrically connected to the respective terminals constituting the electrical connector 31 when the light guide 18 is inserted into the socket described above. Due to the conduction of these terminals and electrodes, the driver 17 and the switches 10 g are connected to the system control unit 22, and the signal cable 16 b that transmits the video signal from the image sensor 16 is connected to the image processing unit 23.

  The system control unit 22 switches the operation mode alternately between the normal observation mode and the fluorescence observation mode every time a specific switch (mode changeover switch) 10g is operated. Then, the system control unit 22 emits white light from the white light source 245 in any operation mode.

  In the normal observation mode, the system control unit 22 controls the filter motor 242 so that the rotary filter 241 is stopped at the rotational position where the transmission part of the rotary filter 241 enters the optical path of white light. As a result, the entire white light always enters the light guide 18 and is irradiated to the subject through the light distribution lens 11. At the same time, the system control unit 22 controls the drive motor 19 to stop the ball lens 120 at the rotational position where the excitation light cut coating 120 a is retracted from the optical path of the subject light, and the image formed by the objective optical system 12. Is commanded to the driver 17 to control the image sensor 16 so as to be imaged every predetermined vertical synchronization period. As a result, a video signal obtained by capturing a subject image by reflected white light on the subject surface is output from the image sensor 16 and input to the image processing unit 23 at each vertical synchronization period.

  On the other hand, when the operation mode is switched to the fluorescence observation mode, the system control unit 22 rotates the rotary filter 241 at a constant speed of twice the vertical synchronization period and transmits the transmission unit or excitation light at every vertical synchronization timing. The filter motor 242 is controlled so that the center of the filter intersects the optical axis of the condenser lens 243, respectively. As a result, in the vertical synchronization period, the light that enters the light guide 18 and is irradiated on the subject through the light distribution lens 11 is alternately switched between white light and excitation light. At the same time, the system control unit 22 rotates the ball lens 120 at a constant speed of four times the vertical synchronization period, and while the object is irradiated with white light, the excitation light cut coating 120a is applied to the object light. Retreating from the optical path and driving so that the center of the excitation light cut coating 120a intersects the optical axis of the entire objective optical system 12 at the timing when the center of the excitation light filter of the rotary filter 241 intersects the optical axis of the condenser lens 243. In addition to controlling the motor 19, the driver 17 is instructed to control the image sensor 16 so that an image formed by the objective optical system 12 is captured at each timing of vertical synchronization. It should be noted that the period during which the outer edge of the excitation light cut coating 120a crosses the optical path of the subject light is spent for the image sensor 16 to transfer the video signal, and the outer edge of the excitation light cut coating 120a is outside the optical path of the subject light. Imaging (that is, charge accumulation) is performed by the imaging element 16 only within the period. As a result, only a video signal obtained by capturing a subject image by reflected white light on the subject surface (referred to as a “white light video signal” for convenience) and fluorescence emitted from living tissue excited by excitation light. A video signal (referred to as a “fluorescent video signal” for convenience) obtained by capturing the subject image is alternately output from the image sensor 16 for each vertical synchronization period and enters the image processing unit 23.

  The system control unit 22 is also connected to the image processing unit 23, and also notifies the image processing unit 23 of the vertical synchronization timing and the current operation mode. While the operation mode notified from the system control unit 22 is the normal observation mode, the image processing unit 23 converts the video signal input from the image sensor 16 into a video signal and outputs it to the monitor 30 as it is. . On the other hand, while the operation mode notified from the system control unit 22 is the fluorescence observation mode, the image processing unit 23 continuously distributes the luminance value distribution of the white light video signal and the fluorescence video signal input from the image sensor 16. In the latter case, a portion that is reflected as a dark portion but is not a dark portion in the former is identified as a lesion portion, and the identified lesion portion is the original reference video signal in a specific color. A video signal superimposed on the inside (referred to as “diagnostic video signal” for convenience) is generated, and the diagnostic video signal is converted into a video signal and output to the monitor 30.

  The surgeon performing the operation using the fluorescence endoscope system configured as described above switches the operation mode of the light source processor device 20 to the normal observation mode by appropriately operating the switch 10g of the fluorescence observation endoscope 10. After that, the intra-body cavity insertion portion 10a of the fluorescence observation endoscope 10 is inserted into the body cavity of the subject while watching the image projected on the monitor 30. At this time, as described above, white light is always introduced into the light guide 18 by the control of the system control unit 22, and the ball lens 120 is in a state where the excitation light cut coating 120a is retracted out of the optical path of the subject light. It has stopped. Therefore, all the components of the reflected light composed of the components reflected in the spectrum corresponding to the color of the subject surface among the white light irradiated on the subject surface are captured without being blocked by the excitation light cut coating 120a. Heading to the imaging surface of the element 16 Therefore, the video displayed on the monitor 30 by the video signal obtained based on the incident light accurately reproduces the color distribution on the surface of the subject.

  When the surgeon captures a site that appears to be a lesion in the image displayed on the monitor 30 in this way, the operation mode of the light source processor device 20 is switched to the fluorescence observation mode by operating the mode switch 10g. . Then, the rotation filter 241 and the ball lens 120 rotate in synchronization with each other under the control of the system control unit 22. As a result, at each vertical synchronization period, the light applied to the subject is switched between white light and excitation light, and while the white light is applied to the subject, the color of the subject surface is changed as described above. While an accurately reproduced white light video signal is obtained and the subject is irradiated with the excitation light, the excitation light component is blocked by the excitation light cut coating 120a, and the fluorescence is based only on the fluorescence emitted by the living tissue. A video signal is obtained. The surgeon determines whether or not the site is a lesion by viewing the video displayed on the monitor 30 by the diagnostic video signal generated based on the white light video signal and the fluorescent video signal. Do it.

As described above, according to the present embodiment, an installation space for the mechanism for driving the ball lens 120 (that is, the drive motor 19) is necessary, but the type of excitation light cut filter is retracted from the optical path of the subject light. Evacuation space becomes unnecessary. Therefore, the outer diameter of the body cavity insertion portion 10a of the fluorescence observation endoscope 10 is not increased.
[Modification]

  In the above-described embodiment, in the fluorescence observation mode, the system control unit 22 rotates the rotary filter 241 and the ball lens 120 at a constant speed, and the image processing unit 23 performs the white light video signal and the fluorescence video signal. Based on the above, a diagnostic video signal is generated. By modifying this, the system control unit 22 controls the filter motor 242 to stop the rotary filter 241 at the rotational position where the excitation light filter of the rotary filter 241 has entered the optical path of white light, and the excitation light. The drive motor 19 may be controlled so that the ball lens 120 is stopped at a rotational position where the center of the cut coating 120 a coincides with the optical axis of the objective optical system 12. Then, only the fluorescent video signal is always input to the image processing unit 23. In this case, the image processing unit 23 converts the fluorescent video signal into a video signal as it is and displays the video on the monitor 30. As a result, since the fluorescence intensity distribution of the subject is displayed on the monitor 30, the surgeon determines the presence / absence of a lesion based on the fluorescence intensity distribution.

  In this case, since the ball lens 120 is not rotated at a constant speed during the fluorescence mode, it is not necessary to consider the existence of a period in which the outer edge of the excitation light cut coating 120a crosses the optical path of the subject light. Accordingly, the outer diameters of the excitation light cut coating 120a and the ball lens 120 can be made as small as possible, and thus the outer diameter of the body cavity insertion portion 10a can be further reduced.

Embodiment 2

  FIG. 4 is a rotation filter as a rotation optical element substituted for the ball lens 120 of the first embodiment described above in the fluorescence observation endoscope constituting the endoscope system according to the second embodiment of the present invention. 130 shows a longitudinal section. The rotation filter 130 has a regular quadrangular prism shape (cubic shape) arranged so that its central axis is orthogonal to the optical axis of the entire objective optical system 12, and is driven to rotate about the central axis as a rotation axis. It is held by a motor 19. An excitation light cut coating 130 a is applied to one side surface of the rotation filter 130 that is parallel to the rotation axis.

  In the second embodiment, the system control unit 22 and the image processing unit 23 operate in the same manner as the modified example of the first embodiment described above. That is, in the normal observation mode, the surface adjacent to the excitation light cut coating 130a of the rotation filter 130 is inserted into the optical path of the subject light, and the excitation light cut coating 130a is retracted from the optical path of the subject light (second state). The rotation filter 130 is stopped at the rotation position), and in the fluorescence observation mode, the excitation light cut coating 130a in the rotation filter 130 is rotated in the state (first rotation position) inserted in the optical path of the subject light. The filter 130 is stopped.

The rotating filter 130 does not exert power on the subject light both in the normal observation mode and in the fluorescence observation mode. Accordingly , the degree of freedom in designing other lenses of the objective optical system 12 is increased.

  Other functions and effects of the second embodiment are exactly the same as those of the first embodiment described above, and a description thereof will be omitted.

Embodiment 3

  FIG. 5 shows a rotating lens as a rotating optical element that can be used in place of the ball lens 120 of the first embodiment described above in a fluorescence observation endoscope that constitutes an endoscope system according to the third embodiment of the present invention. 140 shows a longitudinal section. The rotating lens 140 has a surface on which the excitation light cut coating 130a is applied in the rotation filter 130 of the above-described second embodiment (an area on which the excitation light cut coating is applied on the surface of the rotation optical element), And it has a shape equivalent to the surface adjacent to this (the region inserted into the optical path of the subject light at the second rotation position) having the same lens surface shape with the same refraction action. The lens surface shape is not limited to a spherical surface like the ball lens 120 of the first embodiment, and may be an aspherical shape. Therefore, the rotation lens 140 can bear a part of the performance required for the objective lens 12 without causing much aberration due to the rotation lens 140 itself. Further, the excitation light cut coating 140a may be provided on a plane facing the lens surface.

  In the third embodiment, the system control unit 22 and the image processing unit 23 operate in the same manner as the modified example of the first embodiment described above. That is, in the normal observation mode, the lens surface adjacent to the excitation light cut coating 140a in the rotating lens 140 is inserted in the optical path of the subject light adjacent to the optical filter 15 side, and the excitation light cut coating 140a is applied to the subject light. The rotating lens 140 is stopped in the state of being retracted from the optical path (second rotating position), and in the fluorescence observation mode, the excitation light cut coating 140a in the rotating lens 140 is close to the optical filter 15 side and transmits the subject light. The rotating lens 140 is stopped in the state inserted in the optical path (first rotating position).

  Therefore, according to the third embodiment, the degree of freedom in designing the other lenses of the objective optical system 12 is increased as compared with the first embodiment described above, and the objective optics is compared with the second embodiment described above. There is an advantage that the total length of the system 12 can be kept short.

  Other functions and effects of the second embodiment are exactly the same as those of the first embodiment described above, and a description thereof will be omitted.

Embodiment 4

  FIG. 6 shows a rotation lens as a rotation optical element that can be used in place of the ball lens 120 of the first embodiment described above in a fluorescence observation endoscope constituting an endoscope system according to the fourth embodiment of the present invention. 150. The rotating lens 150 has a surface facing the lens surface of the rotating lens 140 of the third embodiment described above and a surface facing the surface subjected to the excitation light cut coating and a surface subjected to the excitation light cut coating. The lens surface shape is provided so that the surfaces facing the surfaces adjacent to each other have the same refractive action.

  In the fourth embodiment, the system control unit 22 and the image processing unit 23 operate in the same manner as the modified example of the first embodiment described above. That is, in the normal observation mode, the lens surface adjacent to the excitation light cut coating 150a in the rotating lens 150 is inserted in the optical path of the subject light close to the optical filter 15 side, and the excitation light cut coating 150a is applied to the subject light. In the state of retracting from the optical path (second rotation position), the rotation lens 150 is stopped, and in the fluorescence observation mode, the excitation light cut coating 150a in the rotation lens 150 is close to the optical filter 15 side and transmits the subject light. The rotation lens 150 is stopped in the state inserted in the optical path (first rotation position).

  Therefore, according to the fourth embodiment, in the above-described third embodiment, the power that only one surface of the pair of surfaces of the rotating lens 140 inserted into the optical path of the subject light bears the other. Since the surface can be shared, the degree of freedom in designing the lens is further increased compared to the third embodiment, and the total length of the objective optical system 12 can be kept short.

  Other functions and effects of the fourth embodiment are exactly the same as those of the first embodiment described above, and a description thereof will be omitted.

Schematic which shows the internal structure of the endoscope system by the 1st Embodiment of this invention. External view of fluorescence observation endoscope Optical configuration diagram showing the optical configuration from the objective optical system to the image sensor The longitudinal cross-sectional view of the rotation filter used for the 2nd Embodiment of this invention Longitudinal sectional view of a rotating lens used in the third embodiment of the present invention The longitudinal cross-sectional view of the rotation lens used for the 4th Embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fluorescence observation endoscope 11 Light distribution lens 12 Objective optical system 16 Image pick-up element 18 Light guide 20 Light source processor apparatus 22 System control circuit 23 Image processing part 24 Light source block 120 Ball lens 241 Rotation filter 242 Filter motor 245 White light source

Claims (4)

Fluorescence observation endoscopy for selectively capturing an image of a subject by reflected light of white light introduced into a body cavity and an image of a subject by fluorescence emitted from living tissue excited by excitation light introduced into the body cavity An endoscope objective optical system that is incorporated in the tip of a mirror and forms each image on the imaging surface of an imaging device,
One or more lenses each having refractive power;
The lens is rotatably held around a rotation axis orthogonal to the optical axis of each lens, and a part of the surface of the lens has an imaging surface of the imaging element at the first rotation position by the rotation. with entire subject light is incident toward, in the second rotational position by the pivoting saw including a rotating optical element excitation light cut coating its entirety is retracted from the optical path of the object light is applied ,
The area where the excitation light cut coating is applied on the surface of the rotating optical element and the area inserted into the optical path of the subject light at the second rotating position have the same refraction action. An endoscope objective optical system characterized by being formed as a lens surface . An area facing the area where the excitation light cut coating is applied on the surface of the rotating optical element, and an area facing the area inserted into the optical path of the subject light at the second rotating position, respectively, according to claim 1 Symbol placement endoscope objective optical system, characterized in that it is formed as a lens surface having the same refraction effect each other. Claim 2 Symbol placement endoscope objective optical system, characterized in that the shape of the rotating optical element is spherical. Fluorescence observation endoscopy for selectively capturing an image of a subject by reflected light of white light introduced into a body cavity and an image of a subject by fluorescence emitted from living tissue excited by excitation light introduced into the body cavity A mirror,
An image sensor that captures an image formed on the imaging surface;
To each form the respective image on the imaging surface of the IMAGING element, one or a plurality of lenses each having a refractive power, and held rotatably about a rotation axis perpendicular the optical axis of each lens In addition, the entire object light toward the imaging surface of the imaging element is incident on a part of the surface of the surface at the first rotation position by the rotation, and the second rotation by the rotation is performed. In the position, an excitation light cut coating that is entirely retracted from the optical path of the subject light is applied , and in the region where the excitation light cut coating is applied and in the second rotation position, the object light Each of the regions inserted into the optical path includes an objective optical system including a rotating optical element formed as a lens surface having the same refractive action .
A fluorescence observation endoscope which is incorporated in the distal end of a long body cavity insertion portion.