JP2016047150A - Endoscope apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple structured endoscope apparatus capable of controlling the moving speed of a movable lens.SOLUTION: An endoscope apparatus comprises: an image pickup device 23; an imaging optical system including at least one movable lens 21 which is movable along an optical axis J1; a shaft member 11 having a cam part 30 which rotates about a rotation axis J2 parallel with the optical axis J1; a drive part 13 rotationally driving the shaft member 11; and a movable lens holding member 14 which has a follower 15 sliding on the cam part 30, and which is movable along the shaft member 11. The cam part 30 includes first and second cum parts of which positions on the rotation axis J2 continuously change circumferentially, and which are the same in their positional changing tendency on the rotation axis J2 and different from each other in their slope with respect to their extending directions, assuming that a point between the first cam part and the second cam part on the cam part 30 is a starting point.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an endoscope apparatus.

  2. Description of the Related Art An endoscope apparatus configured to be able to perform close-up magnification observation by moving a part of lenses of an optical system along an optical axis to change a focal length is known.

  In this type of endoscope apparatus, a shaft member having a cam is widely used for moving the lens, the cam groove is formed on the outer peripheral surface of the shaft member, and the cam surface replacing the cam groove is a shaft member. What is formed in the edge part (for example, refer patent document 1) etc. are known.

JP 2000-22215 A

  The cam groove formed on the outer peripheral surface of the shaft member is typically provided with an end point, and the cam follower is stopped against the end of the cam groove, thereby positioning the movable lens. In this case, the movable lens is reciprocated by repeating the forward rotation and reverse rotation of the shaft member. However, since the cam follower has only one trajectory, in order to control the moving speed of the movable lens, It is necessary to change the rotation speed.

  On the other hand, in the endoscope apparatus described in Patent Document 1, the cam surface is formed around the rotation axis of the shaft member so that the position on the rotation axis is constant in the circumferential direction and different from each other. The movable lens includes a plurality of arranged flat surfaces and a plurality of inclined surfaces connecting two flat surfaces adjacent to each other in the circumferential direction, and the cam follower is placed on any one of the flat surfaces, thereby positioning the movable lens. In this case, the movable lens is reciprocated by rotation of the shaft member in one direction in addition to repeated forward and reverse rotation of the shaft member. That is, there are a plurality of cam follower tracks. However, since the slopes of the plurality of inclined surfaces are uniform, it is necessary to change the rotational speed of the shaft member in order to control the moving speed of the movable lens.

  The present invention has been made in view of the above circumstances, and in an endoscope apparatus that moves a part of lenses of an optical system along an optical axis, the moving speed of a movable lens can be controlled with a simple configuration. An object of the present invention is to provide an endoscopic device that can be used.

  An endoscope apparatus according to an aspect of the present invention is rotatable about an imaging element, an imaging optical system including at least one movable lens movable along the optical axis, and a rotation axis parallel to the optical axis. There is a shaft member having a cam portion that circulates around the rotation shaft, a drive portion that rotationally drives the shaft member, and a follower that slides on the cam portion, and is movable along the shaft member. A movable lens holding member, wherein the cam portion includes a first cam portion and a second cam portion whose positions on the rotation shaft continuously change in the circumferential direction, and the first cam portion and the second cam portion. The cam portion is arranged on the rotating shaft in the extending direction of each of the first cam portion and the second cam portion when the point between the first cam portion and the second cam portion in the cam portion is a starting point. The change tendency of the position at is the same and the gradients are different from each other.

  According to the present invention, in an endoscope apparatus that moves a part of lenses of an optical system along an optical axis, an endoscope apparatus that can control the moving speed of a movable lens with a simple configuration is provided. Can do.

It is a figure showing the composition of an example of an endoscope apparatus for explaining an embodiment of the present invention. It is a figure which shows the structure of the imaging device provided in the front-end | tip part of the insertion part of the endoscope apparatus of FIG. It is a figure which decomposes | disassembles and shows the principal part of the imaging device of FIG. It is a figure which shows the structure of the principal part of the imaging device of FIG. It is a figure which shows an example of operation | movement of the imaging device of FIG. It is a figure which shows an example of operation | movement of the imaging device of FIG. It is a figure which shows the other example of operation | movement of the imaging device of FIG. It is a figure which shows the other example of operation | movement of the imaging device of FIG. It is a figure which shows the structure of the other example of the endoscope apparatus for demonstrating embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an exemplary configuration of an endoscope apparatus for explaining an embodiment of the present invention.

  The endoscope apparatus 1 includes an insertion unit 2 to be inserted into a subject, an operation unit 3 connected to the insertion unit 2, and a universal cord 4 extending from the operation unit 3.

  An illumination optical system that emits illumination light that illuminates the subject and an imaging device 5 that images the illuminated subject are provided at the distal end of the insertion portion 2.

  A connector is provided at the end of the universal cord 4, and the endoscope apparatus 1 processes the image signal acquired by the light source device that generates illumination light and the imaging device 5 via the connector at the end of the universal cord 4. Connected to the processor device.

  2 and 3 show the configuration of the imaging device 5.

  The imaging device 5 includes an imaging optical system including an objective lens 20 and a movable lens 21, and an imaging device such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor that images a subject through the imaging optical system. 23.

  The objective lens 20 is a lens whose position on the optical axis J1 of the imaging optical system is fixed. The objective lens 20 is configured by at least one lens. The objective lens 20 is held by an objective lens holding member 19 fixed to the housing 10.

  The movable lens 21 is a lens that switches a focusing range, and is configured by at least one lens. The movable lens 21 is held by a movable lens holding member 14 that is movable in the optical axis direction.

  A prism 22 is provided behind the movable lens 21. The prism 22 passes through the objective lens 20, further passes through the movable lens 21, and bends the light incident on the prism 22 by approximately 90 degrees to enter the imaging element 23.

  Note that the prism 22 may be omitted, and the imaging element 23 may be disposed on the optical axis J1 behind the movable lens 21.

  The imaging device 5 includes a shaft member 11 that is arranged in parallel with the imaging optical system and is rotatable about a rotation axis J2 that is parallel to the optical axis J1 of the imaging optical system.

  An object-side end (tip portion) 11A of the shaft member 11 is rotatably supported by a tip-side support portion 17 fixed to the housing 10. An end portion (rear end portion) 11 </ b> B opposite to the subject side of the shaft member 11 is rotatably supported by the housing 10 and a rear end side support portion 18 fixed to the housing 10.

  A movable lens holding member 14 that holds the movable lens 21 is fitted to the distal end portion 11A of the shaft member 11 so as to be movable along the rotation axis J2.

  A rotating shaft 12 is fixed to the rear end portion 11B of the shaft member 11. The rotating shaft 12 is connected to a driving unit 13 including an actuator, and the shaft member 11 receives the rotational driving force of the driving unit 13 and is rotated about the rotating shaft J2. In addition, the drive part 13 may be provided in the operation part 3 (refer FIG. 1), and the rotation shaft 12 is connected with the drive part 13 via the wire in that case.

  The shaft member 11 rotated about the rotation axis J2 is provided with a cam portion 30 for moving the movable lens 21 along an optical axis J1 parallel to the rotation axis J2. The movable lens holding member 14 is provided with a fitting hole 14a penetrating the movable lens holding member 14 along the rotation axis J2, and a pin (follower) 15 contacting the cam portion 30 is provided in the fitting hole 14a. Is inserted.

  The pin 15 includes a contact portion 15 a that contacts the cam portion 30 and a shaft portion 15 b that is inserted into the fitting hole 14 a of the movable lens holding member 14. The abutting portion 15 a has a cross-sectional area perpendicular to the shaft portion 15 b larger than that of the shaft portion 15 b, and is sandwiched between the movable lens holding member 14 and the cam portion 30.

  A coil spring 16 is interposed between the distal end side support portion 17 that supports the distal end portion 11A of the shaft member 11 and the movable lens holding member 14 that is fitted to the distal end portion 11A of the shaft member 11. The coil spring 16 urges the pin 15 fixed to the movable lens holding member 14 from the distal end side of the shaft member 11 toward the cam portion 30 along the rotation axis J2.

  The abutment portion 15 a is sandwiched between the movable lens holding member 14 and the cam portion 30 and further biased toward the cam portion 30 by the coil spring 16, so that the pin 15 is prevented from coming off from the movable lens holding member 14. ing.

  4A to 4C show the configuration of the shaft member 11.

  The diameter of the front end portion 11A of the shaft member 11 is smaller than the diameter of the rear end portion 11B, and the cam portion 30 is provided at a step between the front end portion 11A and the rear end portion 11B.

  The cam portion 30 includes a first cam surface 30a and a second cam surface 30b, a third cam surface 30c disposed between one end of the first cam surface 30a and the second cam surface 30b, and a first cam surface. 30a and a fourth cam surface 30d disposed between the other ends of the second cam surface 30b, and the first cam surface 30a to the fourth cam surface 30d are connected in an annular shape around the rotation axis J2. It is formed around.

  The first cam surface 30a and the second cam surface 30b are inclined surfaces whose positions on the rotation axis J2 continuously change in the circumferential direction. The third cam surface 30c and the fourth cam surface 30d are flat surfaces whose positions on the rotation axis J2 are constant in the circumferential direction, and the positions of the third cam surface 30c and the fourth cam surface 30d on the rotation axis J2 Are different from each other.

  The first cam surface 30a and the second cam surface 30b are the first cam surface 30a and the second cam surface 30b when starting from a point between the first cam surface 30a and the second cam surface 30b in the cam portion 30. In each extending direction, the change tendency of the position on the rotation axis J2 is the same and the gradients are different from each other.

  In the illustrated example, starting from a point P on the third cam surface 30c between the first cam surface 30a and the second cam surface 30b, the first cam surface 30a extends in the extending direction (arrow A direction). The second cam surface 30b is also closer to the distal end side of the shaft member 11 in the extending direction (arrow B direction), and the position of the second cam surface 30b is changed on the rotation axis J2. The trends are the same. However, the gradient η1 of the first cam surface 30a and the gradient η2 of the second cam surface 30b are different from each other, and the gradient of the first cam surface 30a is relatively steep (η1> η2).

  In other words, the first cam surface 30a and the second cam surface 30b have “the same change tendency of the position on the rotation axis J2” means that the front end side of the shaft member 11 is positioned in the positive direction ( Increase direction), the rear end side of the shaft member 11 as the negative direction (decrease direction) of the position on the rotation axis J2, and a point between the first cam surface 30a and the second cam surface 30b as a starting point In the extending direction of each of the first cam surface 30a and the second cam surface 30b, the positions of the first cam surface 30a and the second cam surface 30b on the rotation axis J2 both increase or decrease. Any difference in the rate of change (gradient) of the position is acceptable.

  In the endoscope apparatus 1 configured as described above, when switching of the focal length is instructed by an operation in the operation unit 3 (see FIG. 1), the shaft member 11 is rotated by the drive unit 13, and the shaft member 11 is moved. With rotation, the pin 15 slides on the cam portion 30, and the movable lens holding member 14 is moved along the rotation axis J2. Thereby, the movable lens 21 held by the movable lens holding member 14 is moved along the optical axis J1, and the focal length of the imaging device 5 is switched.

  In this example, the shaft member 11 is rotationally controlled by the drive unit 13 so that the pin 15 is disposed on the third cam surface 30 c or the fourth cam surface 30 d of the cam unit 30. Therefore, the movable lens 21 has a position P1 when the pin 15 is disposed on the third cam surface 30c (see FIG. 2) and a position P2 when the pin 15 is disposed on the fourth cam surface 30d (see FIG. 2). ) And the focal length of the imaging device 5 is switched in two stages.

  Even if a slight error occurs in the rotation of the shaft member 11, the third cam surface 30c and the fourth cam surface 30d are flat surfaces whose positions on the rotation axis J2 are constant in the circumferential direction. Accuracy is maintained. Since the movable lens 21 can be positioned without depending on the pin 15, the deformation of the pin 15 and the loss of the shaft member 11 and the pin 15 due to the impact due to the pin are suppressed, and the operation of the endoscope apparatus 1 is suppressed. Reliability and durability can be improved.

  Three or more flat surfaces whose positions on the rotation axis J2 are constant in the circumferential direction are provided, and two flat surfaces adjacent in the circumferential direction are inclined surfaces whose positions on the rotation axis J2 continuously change in the circumferential direction. The focal length of the imaging device 5 may be configured to be switched between three or more stages so as to be connected to each other.

  5 and 6A to 6E show an example of the operation of the pin 15 of the shaft member 11 and the movable lens holding member 14.

  In the example shown in FIGS. 5 and 6A to 6E, the shaft member 11 is rotationally driven in one direction, and the movable lens 21 is reciprocated between the position P1 and the position P2. It is.

  The shaft member 11 is rotated in the arrow C direction by the drive unit 13. The pin 15 slides in the order of the third cam surface 30c → the first cam surface 30a → the fourth cam surface 30d → the second cam surface 30b → the third cam surface 30c →.

  Here, as shown in FIG. 6B, the changing direction of the position of the pin 15 on the rotation axis J2 when sliding on the first cam surface 30a is directed from the rear end side to the front end side of the shaft member 11. This is opposite to the biasing direction of the coil spring 16 (the direction from the front end side to the rear end side of the shaft member 11).

  On the other hand, as shown in FIG. 6D, the direction of change of the position of the pin 15 on the rotation axis J2 when sliding on the second cam surface 30b is from the front end side of the shaft member 11 to the rear end side. This is the same direction as the biasing direction of the coil spring 16 (the direction from the front end side to the rear end side of the shaft member 11).

  In this case, the moving speed of the pin 15 moved along the rotation axis J2 is decelerated by the bias of the coil spring 16 when the pin 15 slides on the first cam surface 30a, and the pin 15 moves to the second cam. When sliding on the surface 30b, the coil spring 16 is accelerated.

  On the other hand, the gradient of the first cam surface 30a is relatively steep, and when the rotational speed of the shaft member 11 is constant, the moving speed of the pin 15 when sliding on the first cam surface 30a. Is larger than the moving speed of the pin 15 when sliding on the second cam surface 30b. Therefore, the influence of acceleration / deceleration due to the urging of the coil spring 16 is offset, and the moving speed of the pin 15 is made uniform on the first cam surface 30a and the second cam surface 30b. Thereby, the moving speed of the movable lens 21 reciprocated between the position P1 and the position P2 can be made uniform, and the focal length switching speed of the imaging device 5 can be made uniform.

  FIGS. 7A to 7E and FIGS. 8A to 8E show other examples of the operation of the pin 15 of the shaft member 11 and the movable lens holding member 14.

  In the examples shown in FIGS. 7A to 7E and FIGS. 8A to 8E, the shaft member 11 is rotationally driven in both forward and reverse directions, and the first cam surface 30a and the second cam surface are driven. The movable lens 21 is moved by selectively sliding the pin 15 on one cam surface of 30b.

  FIGS. 7A to 7E show the case where the pin 15 is slid on the first cam surface 30a having a relatively steep slope, and the pin 15 has the third cam surface 30c → the first cam. It slides in the order of the surface 30a → the fourth cam surface 30d → the first cam surface 30a → the third cam surface 30c →.

  8A to 8E show the case where the pin 15 is slid on the second cam surface 30b whose slope is relatively slow. The pin 15 has the third cam surface 30c → the second cam. It slides in the order of the surface 30b → the fourth cam surface 30d → the second cam surface 30b → the third cam surface 30c →.

  As described above, when the rotational speed of the shaft member 11 is constant, the moving speed of the pin 15 when sliding on the first cam surface 30a having a relatively steep slope is relatively slow. It becomes larger than the moving speed of the pin 15 at the time of sliding on the 2nd cam surface 30b.

  Therefore, without changing the rotational speed of the shaft member 11, the moving speed of the pin 15 is different between when the pin 15 slides on the first cam surface 30a and when the pin 15 slides on the second cam surface 30b. Can be changed in two stages, high speed and low speed. Thereby, the moving speed of the movable lens 21, that is, the switching speed of the focal length of the imaging device 5 can be changed in two stages of high speed and low speed.

  Thus, the moving speed of the movable lens 21 can be controlled by a simple configuration in which the gradients of the first cam surface 30a and the second cam surface 30b are different from each other.

  In the endoscope apparatus 1 described above, the third cam surface 30c and the fourth cam surface 30d are on the rotation axis J2 so that the positional accuracy of the movable lens 21 is maintained even if a rotation error occurs in the shaft member 11. 9 is a flat surface that is constant in the circumferential direction. As shown in FIG. 9, a detection unit 40 for detecting the position of the movable lens 21 on the optical axis J1 is provided and is detected by the detection unit 40. Alternatively, the drive unit 13 may be configured to control the rotation of the shaft member 11 based on the position of the movable lens 21. Accordingly, for example, when a DC motor that can be downsized as compared with a stepping motor but is inferior in accuracy of rotation control is used as an actuator of the drive unit 13, or the rotational driving force of the drive unit 13 is applied to the shaft member 11 via a wire. Even when transmitting to the lens, the positional accuracy of the movable lens 21 can be sufficiently maintained. It is also possible to switch the focal length steplessly by stopping the rotation of the shaft member 11 when the pin 15 reaches any position on the first cam surface 30a and the second cam surface 30b.

  As the detection unit 40, for example, a photo reflector whose output signal changes according to the distance from the movable lens 21 (movable lens holding member 14) can be used. Further, instead of the position of the movable lens 21 on the optical axis J1, the rotation angle of the shaft member 11 may be detected using, for example, a rotary encoder.

  As described above, the endoscope apparatus disclosed in the present specification includes an imaging element, an imaging optical system including at least one movable lens that can move along the optical axis, and the optical axis that is parallel to the optical axis. A shaft member having a cam portion that can rotate about the rotation shaft, and that rotates around the rotation shaft; a drive portion that rotationally drives the shaft member; and a follower that slides on the cam portion; A movable lens holding member movable along the shaft member, and the cam portion includes a first cam portion and a second cam portion whose positions on the rotating shaft continuously change in the circumferential direction, Each of the first cam portion and the second cam portion is an extension of each of the first cam portion and the second cam portion when a point between the first cam portion and the second cam portion in the cam portion is a starting point. In the present direction, the change tendency of the position on the rotation axis is the same, and the gradient is the same. Different.

  The disclosed endoscope apparatus further includes an urging member that urges the follower toward the cam portion along the rotation shaft, and the driving portion rotationally drives the shaft member in one direction. Of the first cam portion and the second cam portion, the change in the position of the follower sliding on the first cam portion and the second cam portion on the rotation shaft is the biasing direction of the biasing member. The slope of the cam portion in the opposite direction is relatively steep.

  Further, in the disclosed endoscope apparatus, the driving unit rotates the shaft member in both forward and reverse directions, and selectively selects one of the first cam unit and the second cam unit with the cam unit. Slide the follower.

  In the disclosed endoscope apparatus, the cam portion includes a third cam portion disposed between one end portions of the first cam portion and the second cam portion, the first cam portion, and the second cam portion. A fourth cam portion disposed between the other end portions of the cam portion, wherein the third cam portion has a constant position on the rotating shaft in the circumferential direction, and the fourth cam portion is The position on the rotating shaft is constant in the circumferential direction, and is disposed at a position different from the third cam portion.

  The disclosed endoscope apparatus further includes a detection unit that detects a position of the movable lens on the optical axis or a rotation angle of the shaft member, and the driving unit detects the movable unit detected by the detection unit. The shaft member is rotationally driven based on the position of the lens or the rotation angle of the shaft member.

DESCRIPTION OF SYMBOLS 1 Endoscope apparatus 5 Imaging apparatus 11 Shaft member 13 Drive part 14 Movable lens holding member 15 Pin (follower)
16 Coil spring (biasing member)
21 Movable lens 23 Image sensor 30 Cam portion 30a First cam surface 30b Second cam surface 30c Third cam surface 30d Fourth cam surface 40 Detector

Claims (5)

An image sensor;
An imaging optical system including at least one movable lens movable along the optical axis;
A shaft member that is rotatable about a rotation axis parallel to the optical axis and has a cam portion that circulates around the rotation axis;
A drive unit that rotationally drives the shaft member;
A movable lens holding member having a follower sliding on the cam portion and movable along the shaft member;
With
The cam portion includes a first cam portion and a second cam portion whose positions on the rotation shaft continuously change in the circumferential direction,
The first cam portion and the second cam portion of the first cam portion and the second cam portion when starting from a point between the first cam portion and the second cam portion in the cam portion. Endoscopic apparatuses having the same change tendency of the position on the rotation axis and different gradients in each extending direction. A biasing member that biases the follower toward the cam portion along the rotation axis;
The drive unit rotationally drives the shaft member in one direction,
Of the first cam portion and the second cam portion, the change in the position of the follower sliding on the first cam portion and the second cam portion on the rotation shaft is the biasing direction of the biasing member. The endoscope apparatus according to claim 1, wherein a gradient of the cam portion opposite to the direction is relatively steep.   2. The drive unit according to claim 1, wherein the drive unit rotationally drives the shaft member in both forward and reverse directions, and selectively slides the follower with one of the first cam unit and the second cam unit. Endoscopic device. The cam portion includes a third cam portion disposed between one end portions of the first cam portion and the second cam portion, and between the other end portions of the first cam portion and the second cam portion. A fourth cam portion disposed,
The position of the third cam portion on the rotating shaft is constant in the circumferential direction,
The internal view according to any one of claims 1 to 3, wherein the fourth cam portion is disposed at a position that is constant in the circumferential direction on the rotation shaft and that is different from the third cam portion. Mirror device. A detection unit that detects a position of the movable lens on the optical axis or a rotation angle of the shaft member;
The endoscope according to any one of claims 1 to 4, wherein the driving unit rotationally drives the shaft member based on a position of the movable lens detected by the detection unit or a rotation angle of the shaft member. apparatus.

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