An endoscope includes a movable lens group that is movable forward and backward in an optical axis direction, a flexible shaft that has a shaft axis, is configured to rotate in a rotation direction about the shaft axis, and moves the movable lens group in the optical axis direction in a case in which the flexible shaft rotates in the rotation direction, a zoom operation knob, a slider that moves forward and backward in a direction of the shaft axis according to an operation of the zoom operation knob, and a power conversion transmission mechanism that rotates the flexible shaft by the forward and backward movement of the slider.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority under 35 U.S.C § 119(a) to Japanese Patent Application No. 2022-134105 filed on Aug. 25, 2022, which is hereby expressly incorporated by reference, in its entirety, into the present application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an endoscope, and particularly relates to an endoscope comprising a zoom operation mechanism for moving a distal end optical system provided on a distal end side of an insertion part forward and backward in an optical axis direction.

2. Description of the Related Art

In general, an endoscope comprises an elongated insertion part to be inserted into a body and a hand operating part connected to a base end side of the insertion part. The insertion part includes a distal end optical system on a distal end side, and displays an observation image of a subject captured from the distal end optical system on a display device, such as a monitor.

JP1998-108828A (JP-H10-108828A) discloses an endoscope that performs focus adjustment by moving an objective lens forward and backward in an optical axis direction. With this endoscope, the objective lens is moved forward and backward in the optical axis direction by operating a focus adjustment knob of the hand operating part is to rotate a flexible shaft, converting the rotational movement into linear movement by a feed screw mechanism, and transmitting the converted linear movement to a lens frame.

Further, an endoscope disclosed in JP2001-166225A moves a movable lens forward and backward in an optical axis direction by rotating a linear transmitting member by the power of a motor, converting the rotational movement into the linear movement by a feed screw mechanism, and transmitting the converted linear movement to a lens frame.

SUMMARY OF THE INVENTION

Since the endoscope disclosed in JP1998-108828A (JP-H10-108828A) is an apparatus that moves the lens forward and backward by manually operating the focus adjustment knob, there is an advantage that costs (manufacturing cost and running cost) can be reduced as compared with the endoscope disclosed in JP2001-166225A that moves the lens forward and backward by the motor. However, JP1998-108828A (JP-H10-108828A) does not describe any zoom operation mechanism for efficiently transmitting an operation force of the focus adjustment knob to the shaft. That is, JP1998-108828A (JP-H10-108828A) does not disclose at all the zoom operation mechanism for efficiently moving the distal end optical system forward and backward in the optical axis direction.

The present invention has been made in view of such circumstances, and is to provide an endoscope comprising a zoom operation mechanism that can efficiently move a distal end optical system forward and backward in an optical axis direction.

An aspect of the present invention relates to an endoscope comprising a distal end optical system that is movable forward and backward in an optical axis direction, a shaft that has a shaft axis, is configured to rotate in a rotation direction about the shaft axis, and moves the distal end optical system in the optical axis direction in a case in which the shaft rotates in the rotation direction, an operation member, a slider that moves forward and backward in a direction of the shaft axis according to an operation of the operation member, and a power conversion transmission mechanism that rotates the shaft by the forward and backward movement of the slider.

According to the aspect of the present invention, it is preferable that the operation member is a rotational operation member configured to be rotationally operated, and the endoscope further comprises a swing member that swings in a case in which the rotational operation member is rotationally operated, and a link member that links the swing member with the slider and moves the slider forward and backward in a direction of the shaft axis in a case in which the swing member swings.

According to the aspect of the present invention, it is preferable that the power conversion transmission mechanism includes an engagement member provided on the slider, and a shaft member that is linked with the shaft and is formed with a spiral engaged part, on an outer peripheral surface, with which the engagement member is engaged, and the shaft member rotates in the rotation direction about the shaft axis by linear movement of the engagement member accompanied by the forward and backward movement of the slider.

According to the aspect of the present invention, it is preferable that the engagement member is a nut including a female screw, and the shaft member is a screw shaft including a male screw which is the engaged part.

According to the aspect of the present invention, it is preferable that the engagement member is a cam pin, and the shaft member is a cam shaft including a cam groove which is the engaged part.

According to the aspect of the present invention, it is preferable that the endoscope further comprises a rotation detection unit that detects a rotation angle of the shaft.

According to the aspect of the present invention, it is preferable that the endoscope further comprises an insertion part, and a hand operating part that is connected to a base end side of the insertion part, in which the operation member, the slider, and the power conversion transmission mechanism are provided on the hand operating part, the shaft is provided from the hand operating part to the insertion part, and the distal end optical system is provided on a distal end side of the insertion part.

According to the aspect of the present invention, it is preferable that the operation member is a rotational operation member configured to be rotationally operated, a bending operation knob that performs a bending operation of the insertion part is provided to be rotationally operated, on the hand operating part, and a rotation axis of the rotational operation member is disposed coaxially with a rotation axis of the bending operation knob.

According to the present invention, the distal end optical system can be efficiently moved forward and backward in the optical axis direction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of an endoscope according to the present invention will be described with reference to the accompanying drawings.FIG.1is an overall configuration diagram of an endoscope10according to the embodiment.

As shown inFIG.1, the endoscope10comprises an insertion part12and a hand operating part14to which a base end side of the insertion part12is connected. A base end of a universal cable16is connected to the hand operating part14. A connector device (not shown) connected to a processor device200is provided at the distal end of the universal cable16. The processor device200comprises a light source device300and an image processing device400. The light source device300comprises a processor-side connector (not shown) to which the connector device is connected. In addition, a display (not shown) that displays an image processed by the image processing device400is connected to the image processing device400. An endoscope system of the present example comprising the endoscope10and the processor device200has a configuration in which the power, the light signal, or the like is transmitted in a noncontact manner between the endoscope10and the processor device200via the connector portion composed of the connector device and the processor-side connector.

The hand operating part14is provided with an air supply/water supply button18, a suction button20, a shutter button22, a zoom operation knob24, a pair of bending operation knobs26, and a forceps insertion part28at predetermined positions, respectively.

The insertion part12has a longitudinal axis A, and includes a soft portion30, a bendable portion32, and a distal end hard portion34from the base end side toward a distal end side. The bending operation is performed on the bendable portion32remotely by rotationally operating the pair of bending operation knobs26provided on the hand operating part14. As a result, a distal end surface36of the distal end hard portion34can be directed in a desired direction.

FIG.2is a front view of the distal end surface36of the distal end hard portion34. As shown inFIG.2, on the distal end surface36of the distal end hard portion34, an observation window38, a pair of illumination windows40A and40B, an air supply/water supply nozzle42, and a forceps port44are arranged at predetermined positions, respectively. As an example, the observation window38is disposed substantially in the center of the distal end surface36, and the illumination windows40A and40B are arranged on both sides of the observation window38. In addition, the air supply/water supply nozzle42is arranged toward the observation window38, and the forceps port44is arranged in a space surrounded by the observation window38, the illumination window40A, and the air supply/water supply nozzle42.

Hereinafter, a configuration of an observation optical system39including the observation window38provided in the distal end hard portion34will be described.FIG.3is a vertical cross-sectional view of the distal end hard portion34along the longitudinal axis A.FIG.4is a vertical cross-sectional view of the observation optical system39along an optical axis P of the observation optical system39. It should be noted that the longitudinal axis A and the optical axis P are parallel to each other.

As shown inFIG.3, the observation window38is attached to a distal end part body46. The distal end part body46is formed in a substantially cylindrical shape, and is formed with a through-hole46A in a direction of the longitudinal axis A. The observation window38is inserted into the through-hole46A from a base end side to a distal end side of the through-hole46A, and then is fixed to the distal end part body46by a screw50. It should be noted that, in the distal end hard portion34, after the contents, such as the observation window38, are fixed to the distal end part body46, an outer peripheral surface of the distal end part body46is covered with an outer cover49, and the distal end surface of the distal end part body46is equipped with a cap48.

As shown inFIG.4, the observation optical system39comprises stationary lens groups54F and54L and movable lens groups56F and56L, and these lens groups are accommodated in a housing52. The stationary lens groups54F and54L and the movable lens groups56F and56L are each composed of one or several lenses.

The stationary lens groups54F and54L are mounted on stationary lens frames58F and58L, respectively, and are fixed to the housing52via the stationary lens frames58F and58L. The stationary lens frames58F and58L are disposed at intervals in a direction of the optical axis P shown inFIG.4.

The movable lens groups56F and56L are disposed between the stationary lens group54F and the stationary lens group54L on the optical axis P and are held by movable lens frames60F and60L, respectively. Arms64F and64L are installed consecutively to the movable lens frames60F and60L, and ring parts66F and66L are formed at the distal ends of the arms64F and64L. A cam shaft68is inserted into the ring parts66F and66L, and the ring parts66F and66L are slidably supported by the cam shaft68. In addition, cam pins70F and70L are projected on the ring parts66F and66L toward the inside of the ring parts66F and66L, and the cam pins70F and70L are engaged with cam grooves68F and68L spirally formed on an outer surface of the cam shaft68. Therefore, by rotating the cam shaft68about an axial center of the cam shaft68, the ring parts66F and66L move to the distal end side (right direction side inFIG.4) or the base end side (left direction side inFIG.4), and the movable lens groups56F and56L move forward and backward along the direction of the optical axis P. In this case, the movable lens groups56F and56L move in a direction close to or away from each other, whereby the focus adjustment or the zoom operation is performed. It should be noted that the lens configuration of the observation optical system39shown inFIGS.3and4is not limited to the embodiment described above, and for example, an embodiment may be adopted in which the stationary lens group may be composed of one group or the movable lens group may be composed of one group or three groups. The movable lens groups56F and56L of the present example are examples of a distal end optical system according to the embodiment of the present invention, and are provided on the distal end side of the insertion part12.

In the cam shaft68, the axial center of the cam shaft68is disposed parallel to the optical axis P of the observation optical system39, and is supported by the housing52in a rotationally movable manner. A flexible shaft74is attached to a base end part of the cam shaft68via a linking tool72.

The flexible shaft74has a shaft axis B, and is provided from the hand operating part14to the insertion part12inFIG.1. The flexible shaft74is configured to rotate in a rotation direction about the shaft axis B by linking a distal end side with the cam shaft68via the linking tool72and linking a base end side with a linking tool76(seeFIG.5), which will be described below, as shown inFIG.4. In a case in which the flexible shaft74rotates in the rotation direction described above, the cam shaft68is rotated about the axial center. As a result, the movable lens groups56F and56L are moved in the direction of the optical axis P, and the focus adjustment or the zoom operation is performed. The flexible shaft74of the present example is an example of a shaft according to the embodiment of the present invention, and is composed of a close contact coil spring as an example. It should be noted that an operation member or the like for rotationally operating the flexible shaft74will be described below.

As shown inFIG.4, a distal end side of a protective tube78is fixed to a base end side of the housing52. The flexible shaft74is protected by being inserted into the protective tube78, and other contents (light guide, signal cable, air supply/water supply tube, and the like) contained in the insertion part12(seeFIG.1) are prevented from coming into contact with the flexible shaft74. Similarly to the flexible shaft74, the protective tube78is provided from the hand operating part14to the insertion part12ofFIG.1.

In addition, an imaging apparatus80is attached to the housing52. The imaging apparatus80is disposed on the hand operating part14(seeFIG.1) side with respect to the stationary lens frame58L. The imaging apparatus80mainly includes a prism82that bends an optical path of the observation optical system39by 90°, and a solid-state imaging element84that is disposed at an image-forming position of the observation optical system39. The imaging apparatus80is attached to the observation optical system39by fixing a lens barrel holder86, which is adhered to the prism82, to the housing52.

Hereinafter, some embodiments (first and second embodiments) of the zoom operation mechanism that rotates the flexible shaft74about the shaft axis B for performing the zoom operation will be described.

First Embodiment of Zoom Operation Mechanism

FIG.5is an explanatory diagram showing a configuration of a zoom operation mechanism90according to the first embodiment. As shown inFIG.5, the zoom operation mechanism90according to the first embodiment comprises a zoom operation knob24, a slider92, and a power conversion transmission mechanism94. The zoom operation knob24, the slider92, and the power conversion transmission mechanism94are each provided in the hand operating part14.

As shown inFIG.1, the zoom operation knob24is provided to be exposed to the outside of the hand operating part14, and is manually operated by an operator who operates the endoscope10. The zoom operation knob24is configured to rotate by being rotatably supported by a frame96of the hand operating part14shown inFIG.5. Further, as an example, a rotation axis C of the zoom operation knob24is disposed coaxially with a rotation axis D (seeFIG.5) of the bending operation knob26(seeFIG.1). With such a configuration, the zoom operation knob24can be easily operated with the finger of the operator who operates the bending operation knob26. In addition, since the rotation axis C is shared with the rotation axis D, it is not necessary to separately provide the rotation axis C, so that the zoom operation mechanism90can be simplified. The zoom operation knob24is an example of an operation member according to the present invention, and is an example of a rotational operation member.

The slider92shown inFIG.5moves forward and backward in the direction of the shaft axis B according to the rotational operation of the zoom operation knob24. Hereinafter, an example of a transmission mechanism98for transmitting a rotational operation force of the zoom operation knob24to the slider92will be described.

The transmission mechanism98of the present example includes a swing member100and a link member102. The swing member100is a rotating ring104that is integrally configured with the zoom operation knob24, and is configured as a protruding portion that protrudes from an outer peripheral portion of the rotating ring104that is rotatable about the rotation axis C. With such a configuration, in a case in which the zoom operation knob24is rotationally operated in a direction indicated by an arrow E inFIG.5, the swing member100can swing in a direction of an arrow F about the rotation axis C. The swing member100is an example of a swing member according to the embodiment of the present invention.

The link member102links the swing member100with the slider92. Specifically, inFIG.5, a left end of the link member102is supported pivotally by the swing member100via a pin106, and a right end of the link member102is supported pivotally by the slider92via a pin108. With such a configuration, in a case in which the swing member100swings in a clockwise direction about the rotation axis C, the link member102can linearly move the slider92in a right direction inFIG.5in the direction of the shaft axis B. Further, in a case in which the swing member100swings in a counterclockwise direction about the rotation axis C, the link member102can linearly move the slider92in a left direction inFIG.5in the direction of the shaft axis B. As a result, the link member102functions as a member that moves the slider92forward and backward in the direction of the shaft axis B. The link member102is an example of a link member according to the embodiment of the present invention.

The power conversion transmission mechanism94shown inFIG.5rotates the flexible shaft74about the shaft axis B by the forward and backward movement of the slider92. Hereinafter, a specific configuration of the power conversion transmission mechanism94will be described with reference toFIGS.6to8.

FIG.6is an overall perspective view of the power conversion transmission mechanism94.FIG.7is a perspective view of a nut110, which is one of components of the power conversion transmission mechanism94.FIG.8is a perspective view of a screw shaft112, which is one of the components of the power conversion transmission mechanism94. As shown inFIGS.6to8, the power conversion transmission mechanism94includes the nut110and the screw shaft112. As shown inFIG.7, the nut110is provided on the slider92. The nut110is configured as a substantially tubular body including a nut axis G and a female screw114is spirally formed on an inner peripheral surface thereof along a direction of the nut axis G. The nut110is an example of an engagement member according to the embodiment of the present invention. It should be noted that the slider92of the present example is configured as a substantially tubular body that covers an outer surface (excluding a flat bottom surface110A ofFIG.7) of the nut110.

As shown inFIG.8, the screw shaft112is a shaft body having an axial center H, and a male screw116is spirally formed on an outer peripheral surface thereof along a direction of the axial center H. The male screw116and the female screw114of the nut110(seeFIG.7) are engaged (screwed) to configure the power conversion transmission mechanism94of the present example as shown inFIG.6. The power conversion transmission mechanism94is an example of a power conversion transmission mechanism according to the embodiment of the present invention. The screw shaft112is an example of a shaft member according to the embodiment of the present invention, and the male screw116is an example of an engaged part according to the embodiment of the present invention.

As an example, the power conversion transmission mechanism94configured as described above is provided in the hand operating part14as follows. That is, as shown inFIG.5, after the axial center H of the screw shaft112is disposed on an extension line of the shaft axis B of the flexible shaft74, a distal end (right end112A ofFIG.6) of the screw shaft112is linked with the base end of the flexible shaft74via the linking tool76. Also, a base end (left end112B inFIG.6) of the screw shaft112is attached to the frame96via a bearing (not shown). As a result, the power conversion transmission mechanism94is provided in the hand operating part14. Further, with the power conversion transmission mechanism94of the present example, in a case in which the slider92moves forward and backward by the rotational operation of the zoom operation knob24, the nut110linearly moves with the forward and backward movement of the slider92. Then, in a case in which the linear movement of the nut110is converted into the rotational movement by the female screw114and the male screw116, the screw shaft112rotates in the rotation direction about the shaft axis B. As a result, the rotation of the screw shaft112is transmitted to the flexible shaft74via the linking tool76, and the flexible shaft74rotates about the shaft axis B.

Hereinafter, an action of the zoom operation mechanism90according to the first embodiment will be described.

In a case in which the zoom operation knob24shown by a solid line inFIG.5is rotationally operated in a counterclockwise direction about the rotation axis C, the swing member100and the rotating ring104swing in a counterclockwise direction from the position shown by the solid line. As a result, the link member102linked with the swing member100is pulled by the swing member100and moves in the left direction inFIG.5, and the slider92linked with the link member102moves in the left direction inFIG.5.

Then, the nut110(seeFIG.6) linearly moves in the left direction with the movement of the slider92in the left direction. Then, the linear movement of the nut110in the left direction is converted into the rotational movement by the female screw114(seeFIG.7) of the nut110and the male screw116(seeFIG.8) of the screw shaft112. As a result, the screw shaft112smoothly rotates in the rotation direction about the shaft axis B (for example, in a clockwise direction CW as the screw shaft112is viewed from the left end112B inFIG.6), the rotation of the screw shaft112is transmitted to the flexible shaft74via the linking tool76, and the flexible shaft74rotates about the shaft axis B. As a result, by rotating the cam shaft68shown inFIG.4, the movable lens groups56F and56L are moved in the direction of the optical axis P, and the zoom operation is performed, for example, on a wide side.

On the contrary, in a case in which the zoom operation knob24shown by a two-dot chain line inFIG.5is rotationally operated in a clockwise direction about the rotation axis C, the swing member100and the rotating ring104swing in a clockwise direction from the position shown by the two-dot chain line. As a result, the link member102linked with the swing member100is pushed by the swing member100and moves in the right direction inFIG.5, and the slider92linked with the link member102moves in the right direction inFIG.5.

Then, the nut110linearly moves in the right direction with the movement of the slider92in the right direction. Then, the linear movement of the nut110in the right direction is converted into the rotational movement by the female screw114(seeFIG.7) of the nut110and the male screw116(seeFIG.8) of the screw shaft112. As a result, the screw shaft112smoothly rotates in the rotation direction about the shaft axis B (for example, in a counterclockwise direction CCW as the screw shaft112is viewed from the left end112B inFIG.6), the rotation of the screw shaft112is transmitted to the flexible shaft74via the linking tool76, and the flexible shaft74rotates about the shaft axis B. As a result, by rotating the cam shaft68shown inFIG.4, the movable lens groups56F and56L are moved in the direction of the optical axis P, and the zoom operation is performed, for example, on a telephoto side.

Therefore, with the zoom operation mechanism90of the first embodiment, since the configuration is adopted in which the slider92is moved forward and backward in the direction of the shaft axis B according to the rotational operation of the zoom operation knob24, and the flexible shaft74is rotated by the power conversion transmission mechanism94by the forward and backward movement of the slider92, the movable lens groups56F and56L can be efficiently moved forward and backward in the direction of the optical axis P. In addition, since the feed screw mechanism including the nut110and the screw shaft112is adopted as the power conversion transmission mechanism94, the linear movement of the slider92can be effectively converted into the rotational movement.

Second Embodiment of Zoom Operation Mechanism

FIG.9is an explanatory diagram showing a configuration of a zoom operation mechanism120according to the second embodiment.

Here, a difference in configuration between the second embodiment shown inFIG.9and the first embodiment shown inFIG.5will be described. The feed screw mechanism including the nut110and the screw shaft112is adopted as the power conversion transmission mechanism94of the first embodiment, whereas a cam mechanism including a cam pin132(seeFIG.11) and a cam shaft134is adopted as a power conversion transmission mechanism130of the second embodiment shown inFIG.9. Since the other configurations (zoom operation knob24, slider92, swing member100, and link member102) are the same, in the description of the zoom operation mechanism120of the second embodiment, the power conversion transmission mechanism130shown inFIGS.10to12will be mainly described.

FIG.10is an overall perspective view of the power conversion transmission mechanism130.FIG.11is a perspective view of a pair of cam pins132which are one of the components of the power conversion transmission mechanism130.FIG.12is a perspective view of the cam shaft134, which is one of the components of the power conversion transmission mechanism130. As shown inFIGS.10to12, the power conversion transmission mechanism130includes the pair of cam pins132and the cam shaft134.

As shown inFIG.11, the slider92is formed in a tubular shape, and the pair of cam pins132are projected from the inner peripheral surface of the slider92to face each other. The cam pin132is an example of an engagement member according to the embodiment of the present invention.

As shown inFIG.12, the cam shaft134is a shaft body having an axial center J, and a cam groove136is spirally formed on an outer peripheral surface thereof along a direction of the axial center J. The cam groove136and the pair of cam pins132(seeFIG.11) are engaged with each other to configure the power conversion transmission mechanism130of the present example as shown inFIG.10. The power conversion transmission mechanism130is an example of a power conversion transmission mechanism according to the embodiment of the present invention. The cam shaft134is an example of a shaft member according to the embodiment of the present invention, and the cam groove136is an example of an engaged part according to the embodiment of the present invention.

As an example, the power conversion transmission mechanism130configured as described above is provided in the hand operating part14as follows. That is, as shown inFIG.9, after the axial center J of the cam shaft134is disposed on an extension line of the shaft axis B of the flexible shaft74, a distal end (right end134A ofFIG.10) of the cam shaft134is linked with the base end of the flexible shaft74via the linking tool76. Also, a base end of the cam shaft134(left end134B inFIG.10) is attached to the frame96via a bearing (not shown). As a result, the power conversion transmission mechanism130is provided in the hand operating part14. Further, with the power conversion transmission mechanism130of the present example, in a case in which the slider92moves forward and backward by the rotational operation of the zoom operation knob24, the pair of cam pins132linearly move with the forward and backward movement of the slider92. Further, in a case in which the linear movement of the pair of cam pins132is converted into the rotational movement by the cam groove136, the cam shaft134rotates in the rotation direction about the shaft axis B. As a result, the rotation of the cam shaft134is transmitted to the flexible shaft74via the linking tool76, and the flexible shaft74rotates about the shaft axis B.

Hereinafter, an action of the zoom operation mechanism120according to the second embodiment will be described. It should be noted that a point that overlaps with the action of the zoom operation mechanism90of the first embodiment will be described repeatedly.

In a case in which the zoom operation knob24shown by a solid line inFIG.9is rotationally operated in a counterclockwise direction about the rotation axis C, the swing member100and the rotating ring104swing in a counterclockwise direction from the position shown by the solid line. As a result, the link member102linked with the swing member100is pulled by the swing member100and moves in the left direction inFIG.9, and the slider92linked with the link member102moves in the left direction inFIG.9.

Then, the pair of cam pins132linearly move in the left direction with the movement of the slider92in the left direction. Then, the linear movement of the pair of cam pins132in the left direction is converted into the rotational movement by the cam groove136(seeFIG.12) of the cam shaft134. As a result, the cam shaft134smoothly rotates in the rotation direction about the shaft axis B (for example, in the clockwise direction CW as the cam shaft134is viewed from the left end134B inFIG.10), the rotation of the cam shaft134is transmitted to the flexible shaft74via the linking tool76, and the flexible shaft74rotates about the shaft axis B. As a result, by rotating the cam shaft68shown inFIG.4, the movable lens groups56F and56L are moved in the direction of the optical axis P, and the zoom operation is performed, for example, on the wide side.

On the contrary, in a case in which the zoom operation knob24shown by a two-dot chain line inFIG.9is rotationally operated in a clockwise direction about the rotation axis C, the swing member100and the rotating ring104swing in a clockwise direction from the position shown by the two-dot chain line. As a result, the link member102linked with the swing member100is pushed by the swing member100and moves in the right direction inFIG.9, and the slider92linked with the link member102moves in the right direction inFIG.9.

Then, the pair of cam pins132linearly move in the right direction with the movement of the slider92in the right direction. Then, the linear movement of the pair of cam pins132in the right direction is converted into the rotational movement by the cam groove136(seeFIG.12) of the cam shaft134. As a result, the cam shaft134smoothly rotates in the rotation direction about the shaft axis B (for example, in the counterclockwise direction CCW as the cam shaft134is viewed from the left end135B inFIG.10), the rotation of the cam shaft134is transmitted to the flexible shaft74via the linking tool76, and the flexible shaft74rotates about the shaft axis B. As a result, by rotating the cam shaft68shown inFIG.4, the movable lens groups56F and56L are moved in the direction of the optical axis P, and the zoom operation is performed, for example, on the telephoto side.

Therefore, with the zoom operation mechanism120of the second embodiment, since the configuration is adopted in which the slider92is moved forward and backward in the direction of the shaft axis B according to the rotational operation of the zoom operation knob24, and the flexible shaft74is rotated by the power conversion transmission mechanism130by the forward and backward movement of the slider92, the movable lens groups56F and56L can be efficiently moved forward and backward in the direction of the optical axis P. Further, since the cam mechanism including the pair of cam pins132and the cam shaft134is adopted as the power conversion transmission mechanism130, the linear movement of the slider92can be effectively converted into the rotational movement.

Rotary Encoder

Here, a rotary encoder140is also provided in the first embodiment shown inFIG.5and the second embodiment shown inFIG.9. The rotary encoder140detects a rotation angle of the flexible shaft74, is linked with the left end112B (seeFIG.6) of the screw shaft112as an example in the first embodiment ofFIG.5, and is linked with the left end134B (seeFIG.10) of the cam shaft134as an example in the second embodiment ofFIG.9. The rotary encoder140is an example of a rotation detection unit according to the embodiment of the present invention.

A detection signal output from the rotary encoder140is input to the processor device200(seeFIG.1) of the endoscope10as an example.FIG.13is a functional block diagram showing a configuration of the processor device200. The processor device200comprises a processor202and a memory204.

As shown inFIG.13, the processor202includes an encoder signal acquisition unit206that acquires the detection signal output from the rotary encoder140, an imaging magnification acquisition unit208that acquires information indicating an imaging magnification corresponding to the detection signal acquired by the encoder signal acquisition unit206from the memory204, a shutter speed setting unit210that sets a shutter speed corresponding to the imaging magnification acquired by the imaging magnification acquisition unit208, and a light amount setting unit212that sets a light amount corresponding to the imaging magnification acquired by the imaging magnification acquisition unit208.

The shutter speed setting unit210sets the shutter speed corresponding to the imaging magnification to a shutter controller214, and the shutter controller214controls a shutter216at the set shutter speed. In addition, the light amount setting unit212sets the light amount corresponding to the imaging magnification to a light source controller302of the light source device300, and the light source controller302controls the light source304with the set light amount.

The processor202executes a command stored in the memory204. A hardware structure of the processor202is various processors as described below. Various processors include a central processing unit (CPU) as a general-purpose processor which acts as various function units by executing software (program), a graphics processing unit (GPU) as a processor specialized in image processing, a programmable logic device (PLD) as a processor of which a circuit configuration can be changed after manufacture, such as a field programmable gate array (FPGA), a dedicated electric circuit as a processor which has a circuit configuration specifically designed to execute specific processing, such as an application specific integrated circuit (ASIC), and the like.

One processing unit may be configured by using one of these various processors, or two or more processors of the same type or different types (for example, a plurality of FPGAs, or a combination of a CPU and an FPGA, or a combination of a CPU and a GPU). Moreover, a plurality of function units may be configured by using one processor. As a first example in which the plurality of function units are configured by using one processor, as represented by a computer such as a client or a server, there is a form in which one processor is configured by using a combination of one or more CPUs and software, and this processor acts as the plurality of function units. As a second example thereof, as represented by a system on chip (SoC), there is a form in which a processor, which implements the functions of the entire system including the plurality of function units by one integrated circuit (IC) chip, is used. As described above, various function units are configured by using one or more of the various processors described above as the hardware structure.

Further, the hardware structures of these various processors are, more specifically, an electric circuit (circuitry) in which circuit elements such as semiconductor elements are combined.

FIG.14is a flowchart showing a flow of processing of setting the shutter speed and setting the light amount by the processor202shown inFIG.13. As shown inFIG.14, in step S10, the encoder signal acquisition unit206(seeFIG.13) acquires the detection signal from the rotary encoder140(seeFIG.13). Next, in step S20, the imaging magnification acquisition unit208(seeFIG.13) acquires the information indicating the imaging magnification corresponding to the detection signal acquired by the encoder signal acquisition unit206(seeFIG.13) from the memory204. Then, in step S30, the shutter speed setting unit210(seeFIG.13) sets the shutter speed corresponding to the imaging magnification acquired by the imaging magnification acquisition unit208(seeFIG.13). Then, in step40, the light amount setting unit212(seeFIG.13) sets the light amount corresponding to the imaging magnification acquired by the imaging magnification acquisition unit208(seeFIG.13). The above description is the flow of processing of setting the shutter speed and setting the light amount by the processor202. It should be noted that step S30and step S40may be processed in parallel or may be processed in a different order.

The processing of the processor202will be briefly described. Since the image blur is likely to occur in a case in which the imaging magnification is increased by the zoom operation, the processor202sets the shutter speed to high speed, and sets the light amount for obtaining a sufficient light amount even at the shutter speed. As a result, it is possible to suppress image blur in a case in which the imaging magnification is increased.

Modification Example

Hereinafter, a modification example according to the “shaft” and the “operation member” which are the configuration requirements of the present invention will be described.

Shaft

As the shaft, the flexible shaft74having a flexibility is described as an example in the embodiment, but the present invention is not limited to this. For example, a rigid (non-flexible) shaft may be applied as the shaft. In this case, the rigid shaft can be applied to a rigid mirror in which the insertion part is composed of a hard member.

Operation Member

As the operation member, the zoom operation knob24configured to rotate is described as an example in the embodiment, but the present invention is not limited to this. For example, an operation member configured to linearly move may be applied. Specifically, a configuration may be adopted in which a knob member corresponding to the operation member is directly linked with the slider92, and the knob member is linearly moved to move the slider92forward and backward. In this case, the zoom operation knob24and the transmission mechanism98(swing member100and link member102) shown inFIGS.5and9are not required. However, from the viewpoint that the operation member can be easily operated with the finger of the operator who operates the bending operation knob26(seeFIG.1), it is preferable to adopt the configurations of the first embodiment (seeFIG.5) and the second embodiment (seeFIG.9) in which the zoom operation knob24and the transmission mechanism98are provided.

Although the endoscope according to the embodiment is described above, the present invention may be improved or modified in some ways without departing from the gist of the present invention.

EXPLANATION OF REFERENCES