JP6495555B1 - Optical unit and endoscope - Google Patents

Abstract

  The optical unit 1 includes a movable lens holding frame 23 that is disposed so as to be movable back and forth with respect to the fixed lens holding frame 21, a biasing member 31 that biases the movable lens holding frame 23 toward the base end side, and a fixed lens holding unit. A drive mechanism 30 that is disposed on the frame 21 and drives the movable lens holding frame 23 toward the distal end against the urging force of the urging member 31, and parallel to the photographing optical axis O formed on the fixed lens holding frame 21. An adjustment member 26 that is fixed in a state in which the posture is uniquely determined by line contact or surface contact with the two edges C or the tapered surface 29, and that adjusts the advance / retreat position by contacting the movable lens holding frame 23. It has.

Description

  The present invention relates to an optical unit and an endoscope that are provided at a distal end portion of an endoscope insertion portion and have a movable lens driving unit that moves a part of an objective lens.

  An endoscope having an imaging unit that can be introduced into the living body or the structure from outside the living body or the structure to observe a portion that is difficult to observe, such as the inside of the living body or the structure. Mirrors are used, for example, in the medical and industrial fields.

  An imaging unit of an endoscope captures an objective lens that forms a subject image and a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) sensor that is generally disposed on the imaging surface of the objective lens. It comprises an element.

  For example, Japanese Patent Application Laid-Open No. 2013-116349 has a function (magnification function, zoom function) that has a movable lens in an objective lens and changes the photographing magnification by moving the movable lens in the optical axis direction. An endoscope optical unit provided is disclosed.

  The optical unit disclosed in Japanese Patent Application Laid-Open No. 2013-116349 photographs a pressing force applied to a contacted surface from a contact member by the contact member contacting the contacted surface of the movable lens holding frame. By distributing in a direction substantially perpendicular to the optical axis and in a second direction along the photographic optical axis, the movable lens holding frame is extended in the direction along the photographic optical axis, and the desired optical characteristics are stabilized. A technique has been disclosed that prevents the occurrence of vignetting by improving the reproducibility of stopping the movable lens holding frame at a certain wide end position while preventing the image from shaking when moving forward and backward. .

  By the way, the optical unit for endoscopes is likely to suffer from defects in optical performance such as one-sided blur due to the inclination and decentration of the objective optical system, etc., with the recent decrease in pitch due to the increase in the number of pixels of the image sensor. .

  For this reason, a conventional optical unit having a movable lens holding frame that moves back and forth as described in Japanese Patent Application Laid-Open No. 2013-116349 has a backlash that fits between the movable lens holding frame and the fixed lens frame. When there is a stick, the movable lens holding frame has a problem that the front and rear stop positions vary and the movable lens holding frame does not stop at a position that satisfies the desired optical characteristics.

  Accordingly, the conventional optical unit is required to have high accuracy of the movable lens holding frame and the fixed lens frame.

  Furthermore, the optical unit is required to be miniaturized to reduce the diameter of the insertion portion, and the optical characteristics are likely to be affected by small components even with the same dimensional accuracy as in the past.

  For this reason, there is a problem in that the optical performance cannot be satisfied unless the component parts that define the movement stop position of the movable lens holding frame are small and the parts accuracy cannot be secured.

  From the above, the conventional optical unit has a problem that it is difficult to ensure stable optical characteristics when it is further downsized.

  Therefore, in view of the above-described circumstances, the present invention aims to easily set the advance / retreat stop position of the movable lens holding frame so that a predetermined optical performance can be stably obtained at the time of assembly even if it is downsized. An optical unit and an endoscope that can be adjusted are realized.

An optical unit according to an aspect of the present invention includes a fixed lens holding frame that holds a fixed lens, a movable lens holding frame that is arranged to be movable forward and backward relative to the fixed lens holding frame, and the movable lens. An arm portion provided on the lens holding frame and projecting to the outside of the fixed lens holding frame; an urging member for urging the arm portion toward the base end; and an urging force provided on the fixed lens holding frame. A driving mechanism that presses the arm to drive the movable lens holding frame toward the distal end against a biasing force of a member; and a holding base formed on the fixed lens holding frame; A tubular member that abuts on the arm portion in order to adjust the advancing / retreating position of the holding frame, and the fixed lens holding frame is formed with a slit through which the arm portion penetrates. A rectangular parallelepiped along the slit One of the wall portions are formed, the tubular member, the two ridgelines is a boundary between the two walls facing the wall with the two walls projecting end face of, and is fixed by an adhesive.

An endoscope according to an aspect of the present invention includes a fixed lens holding frame that holds a fixed lens, a movable lens holding frame that is disposed to be movable forward and backward with respect to the fixed lens holding frame, and holds the movable lens; An arm portion provided on the movable lens holding frame and projecting to the outside of the fixed lens holding frame; a biasing member for biasing the arm portion toward the base end side; and disposed on the fixed lens holding frame. A drive mechanism that presses the arm to drive the movable lens holding frame toward the distal end against the urging force of the biasing member, and a movable base that is fixed to a holding base formed on the fixed lens holding frame. A tubular member that abuts on the arm portion to adjust the advancing / retreating position of the lens holding frame, and the fixed lens holding frame is formed with a slit through which the arm portion penetrates. Two rectangular parallelepiped shapes along the slit Parts are formed, the tubular member, the two ridgelines is a boundary between the two walls facing the wall with the two walls projecting end face of the comprises an optical unit is fixed by adhesive .

The figure explaining an endoscope provided with an optical unit Sectional drawing explaining the outline of the front-end | tip part of the insertion part of an endoscope Front view of the endoscope optical unit viewed from the front end side IV-IV sectional view of FIG. Partial sectional view for explaining a state in which the movable lens holding frame has moved to the proximal end side The perspective view which showed the state by which the adjustment member was arrange | positioned by the fixed frame An exploded perspective view showing a state in which the adjustment member is disposed on the fixed frame The perspective view which showed the state in which an adjustment member is adjusted back and forth The perspective view which shows the state in which the adjustment member was fixed to the fixed frame Partial sectional view showing a state in which the adjustment member is fixed to the fixed frame The fragmentary sectional view which shows the state by which the adjustment member of the 1st modification was fixed to the fixed frame The perspective view which shows the state in which the adjustment member of the 2nd modification was mounted in the holding stand. The perspective view which shows the state by which the adjustment member of the 3rd modification was fixed to the holding stand. The perspective view which shows the state by which the adjustment member of the 4th modification was fixed to the holding stand. The perspective view which shows the state in which the adjustment member of the 5th modification was mounted in the holding stand. The top view which shows the adjustment member of the 5th modification, and the arm part of a movable lens holding frame The perspective view which shows the state in which the adjustment member of the 6th modification was mounted in the holding stand. The fragmentary sectional view which shows the state by which the adjustment member of the 7th modification was fixed to the holding stand The fragmentary sectional view which shows the state by which the adjustment member of the 8th modification was fixed to the holding stand. The fragmentary sectional view which shows the state by which the adjustment member of the 9th modification was fixed to the holding stand The fragmentary sectional view which shows the state by which the adjustment member of the 10th modification was fixed to the holding stand.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
In the drawings used for the following description, the scale of each component is made different in order to make each component recognizable on the drawing. It is not limited only to the quantity of the component described in (1), the shape of the component, the ratio of the size of the component, and the relative positional relationship of each component.
Hereinafter, an example of an embodiment of the present invention will be described. FIG. 1 is a diagram illustrating an endoscope including an endoscope optical unit, FIG. 2 is a cross-sectional view illustrating an outline of a distal end portion of an insertion portion of the endoscope, and FIG. 3 is a diagram illustrating an endoscope optical unit. FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3, FIG. 5 is a partial sectional view for explaining a state in which the movable lens holding frame has moved to the proximal side, and FIG. FIG. 7 is an exploded perspective view showing a state in which the adjustment member is arranged on the fixed frame, and FIG. 8 is a perspective view showing a state in which the adjustment member is adjusted back and forth. 9 is a perspective view showing a state in which the adjustment member is fixed to the fixed frame, and FIG. 10 is a partial cross-sectional view showing a state in which the adjustment member is fixed to the fixed frame.

  First, with reference to FIG. 1, an example of a configuration of an endoscope 101 including an optical unit 1 according to the present invention will be described. In the following, the optical unit 1 mounted on the endoscope here is simply referred to as an imaging unit 1. The endoscope 101 of the present embodiment has a configuration that can be introduced into a subject such as a human body and optically images a predetermined observation site in the subject. The subject into which the endoscope 101 is introduced is not limited to a human body, and may be another living body or an artificial object such as a machine or a building.

  The endoscope 101 includes an insertion portion 102 introduced into the subject, an operation portion 103 located at the proximal end of the insertion portion 102, and a universal cord 104 extending from a side portion of the operation portion 103. It is mainly composed.

  The insertion portion 102 is disposed at the distal end portion 110 disposed at the distal end, the bendable bending portion 109 disposed on the proximal end side of the distal end portion 110, and the proximal end side of the bending portion 109. A flexible tube portion 108 having flexibility and connected to the distal end side is continuously provided. Note that the endoscope 101 may have a so-called rigid endoscope that does not include a flexible portion in the insertion portion.

  As will be described in detail later, the distal end portion 110 is provided with an imaging unit 1 as an optical unit and an illumination light emitting portion 113 (not shown in FIG. 1) shown in FIG. In addition, the operation unit 103 is provided with an angle operation knob 106 for operating the bending of the bending unit 109.

  The operation unit 103 is provided with a scaling operation unit 107 which is a lever switch for instructing an operation of an actuator 30 as a drive mechanism unit described later and performing an imaging magnification changing operation of the imaging unit 1. The scaling operation unit 107 may be other types such as a rotary switch, a push switch, or a touch sensor.

  An endoscope connector 105 connected to the external device 120 is provided at the base end portion of the universal cord 104. The endoscope 101 includes a universal cord 104, an electric cable 115 inserted into the operation unit 103 and the insertion unit 102, and an optical fiber bundle 114 (not shown in FIG. 1) shown in FIG. Yes.

  The electric cable 115 is configured to electrically connect the connector unit 105 and the imaging unit 1. By connecting the connector unit 105 to the external device 120, the imaging unit 1 is electrically connected to the external device 120 via the electric cable 115. Via the electric cable 115, power is supplied from the external device 120 to the imaging unit 1, and communication between the external device 120 and the imaging unit 1 is performed.

  The optical fiber bundle 114 is configured to transmit light emitted from the light source unit included in the external device 120 to the illumination light emitting unit 113 of the distal end portion 110. The light source unit may be configured to be disposed on the operation unit 103 or the distal end portion 110 of the endoscope 101.

  The external device 120 includes, for example, a light source unit, a power supply unit 120a, an image processing unit 120b, and an image display unit 121. The power supply unit 120a is configured to output electric power for operating the actuator 30 included in the imaging unit 1 in accordance with the operation of the scaling operation unit 107 by the user.

  As will be described in detail later, as an example in the present embodiment, the power supply unit 120a includes a shape memory alloy wire (hereinafter abbreviated as SMA wire) 36 (hereinafter abbreviated as SMA wire) 36, which is a wire-shaped shape memory alloy of the actuator 30. (Not shown) is configured to apply a current.

  The image processing unit 120 b has a configuration that generates a video signal based on the imaging element output signal output from the imaging unit 1 and outputs the video signal to the image display unit 121. That is, the optical image picked up by the image pickup unit 1 is displayed on the display unit 121 as a video. Note that some or all of the power supply unit 120a, the image processing unit 120b, and the image display unit 121 may be arranged in the endoscope 101 instead of the external device 120.

  Next, the configuration of the distal end portion 110 will be described. As shown in FIG. 2, the imaging unit 1 and the illumination light emitting unit 113 are disposed at the distal end portion 110.

  In the present embodiment, as an example, the imaging unit 1 is disposed so as to capture the distal end direction along the longitudinal direction (insertion axis direction) of the insertion portion 102 indicated by an arrow A in FIG. More specifically, the imaging unit 1 is arranged such that the photographing optical axis (hereinafter abbreviated as “optical axis”) O of the objective lens 11 is along the longitudinal direction of the insertion portion 102. Note that the imaging unit 1 may be arranged such that the optical axis O forms a predetermined angle with respect to the longitudinal direction of the insertion portion 102.

  Further, the illumination light emitting unit 113 has a configuration for emitting light emitted from the tip of the optical fiber bundle 114 so as to illuminate the subject of the imaging unit 1. In the present embodiment, the illumination light emitting portion 113 is configured to emit light from the distal end surface of the distal end portion 110 toward the distal end direction along the longitudinal direction of the insertion portion 102.

  The imaging unit 1 and the illumination light emitting unit 113 are held by a holding unit 111 provided at the distal end portion 110. The holding part 111 is a hard member exposed on the tip surface of the tip part 110, and is provided with through holes 111 a and 111 b that are drilled along the longitudinal direction of the insertion part 102. In the through holes 111a and 111b, the imaging unit 1 and the illumination light emitting unit 113 are fixed by a method such as adhesive or screwing. In addition, the optical fiber bundle 114 is inserted and fixed in the through hole 111b from the base end side.

  Next, the configuration of the imaging unit 1 of the present embodiment will be described. As shown in FIGS. 2 and 3, the imaging unit 1 includes an objective lens 11 and a lens barrel portion 20 that holds an imaging device 12 disposed on the image side of the objective lens 11, and the lens barrel portion 20 side. And an actuator 30 which is a drive mechanism section disposed in the section.

  As shown in the sectional view of FIG. 4, the objective lens 11 is composed of an optical system member such as a plurality of lenses that form a subject image.

  The objective lens 11 according to the present embodiment includes a fixed lens 11a composed of one or a plurality of lenses whose positions are fixed in the lens barrel portion 20, and 1 that is movable in the optical axis O direction in the lens barrel portion 20. The movable lens 11b includes one or a plurality of lenses.

  In the present embodiment, as an example, the objective lens 11 is configured such that as the movable lens 11b is positioned on the image side (tele end position), the photographing magnification increases (tele state where the angle of view decreases). .

  In addition, the objective lens 11 of the present embodiment has a tele state in which the photographing magnification increases as the movable lens 11b becomes the tele end position on the image side. However, the objective lens 11 has the movable lens 11b on the image side. As a wide position located at, a wide state in which the photographing magnification is low may be used.

  Further, in the present embodiment, the fixed lens 11a is disposed before and after the movable lens 11b. However, the movable lens 11b may be disposed on the most object side of the objective lens 11 or may be configured with an objective. The lens 11 may be arranged on the most image side.

  The objective lens 11 may include other optical system members such as a diaphragm, a prism, and an optical filter.

  The image pickup device 12 is formed by arranging a plurality of light receiving devices that photoelectrically convert incident light. For example, the image pickup device 12 is generally referred to as a CCD (charge coupled device), a CMOS (complementary metal oxide semiconductor) sensor, or the like. Alternatively, various other types of imaging devices can be applied. The image sensor 12 is disposed such that the light receiving element is positioned on the image forming surface of the objective lens 11.

  A cover glass 13 is adhered to the light receiving surface of the image sensor 12 on which the light receiving element is disposed by an adhesive. A circuit board 14 is electrically connected to the image sensor 12. The circuit board 14 is electrically connected to the electric cable 115.

  First, the configuration of the lens barrel 20 will be described. The lens barrel 20 that holds the objective lens 11 and the image pickup element 12 described above is formed of a fixed frame 21 that is a fixed lens holding frame, which is mainly formed of a metal such as aluminum or stainless steel or a non-magnetic material of hard resin, and an object. A side lens holding frame 22, a movable lens holding frame 23, and an image side lens holding frame 24 are included.

  The fixed frame 21, the object side lens holding frame 22, and the image side lens holding frame 24 are each substantially cylindrical members, and their positions are fixed by an adhesive, press-fitting, or the like.

  One cover glass 13 is fixed to the base end side of the fixed frame 21 with an adhesive. That is, the image sensor 12 is fixed to the base end side of the fixed frame 21 via the two cover glasses 13.

  A substantially cylindrical cylindrical portion 21 a is provided on the distal end side of the fixed frame 21. A slit 21b, which is a through hole into which an arm portion 23b of a movable lens holding frame 23 described later is inserted, is formed on a side surface portion of the cylindrical portion 21a. The slit 21b is a long hole whose longitudinal direction is substantially parallel to the optical axis O.

  In addition, a holding portion 21c that protrudes outward in the radial direction (direction perpendicular to the optical axis O) in an arm shape is provided on the side of the fixed frame 21 on the base end side of the slit 21b. The slit 21b and the holding portion 21c are provided in substantially the same circumferential direction with respect to the optical axis O when viewed from the optical axis O direction.

  The holding portion 21 c is a portion that positions and holds the distal end portion of the guide pipe 33 that constitutes the actuator 30. Specifically, a through hole substantially parallel to the optical axis O is formed in the holding portion 21c, and the substantially cylindrical guide pipe 33 is inserted into the through hole and fixed. In the guide pipe 33, a pressing portion 32 is disposed so as to be movable back and forth in the direction of the optical axis O.

  An object side lens holding frame 22 is fixed to the distal end side of the cylindrical portion 21 a of the fixed frame 21. The object side lens holding frame 22 is a substantially cylindrical member that holds the fixed lens 11a of the objective lens 11 that is located on the object side of the movable lens 11b.

  On the side surface of the object-side lens holding frame 22, a convex portion 22 a that protrudes outward in the radial direction (a direction orthogonal to the optical axis O) in an arm shape is provided.

  The protrusion 22a is provided in the substantially same circumferential direction as the slit 21b with respect to the optical axis O when viewed from the optical axis O direction. The convex portion 22 a is a part that constitutes a part of the actuator 30.

  A movable lens holding frame 23 is disposed inside the cylindrical portion 21a of the fixed frame 21 so as to be movable back and forth in the direction of the optical axis O. The movable lens holding frame 23 is a moving frame member that holds the movable lens 11 b of the objective lens 11.

  The movable lens holding frame 23 holds the movable lens 11b inside, and has an arm portion 23b protruding outward from the side surface in the radial direction (direction orthogonal to the optical axis O).

  The movable lens holding frame 23 is disposed in the cylindrical portion 21a of the fixed frame 21 so as to be able to advance and retract. That is, the movable lens holding frame 23 is configured to be slidable in the direction of the optical axis O in the cylindrical portion 21a.

  In the state where the movable lens holding frame 23 is disposed in the cylindrical portion 21a, the arm portion 23b is inserted into the slit 21b. By inserting the arm portion 23b into the slit 21b, the rotation of the movable lens holding frame 23 around the optical axis O is restricted.

  The arm portion 23b comes into contact with the flat surface portion on the base end side of the convex portion 22a of the object side lens holding frame 22 when the movable lens holding frame 23 is moved to the tip side which is the object side. Thereby, the movement of the movable lens holding frame 23 is restricted, and the movement thereof is positioned.

  FIG. 4 shows a state in which the arm portion 23b is in contact with the flat surface portion on the proximal end side of the convex portion 22a, and the movable lens holding frame 23 is located on the most distal side in the movable range.

  On the other hand, when the movable lens holding frame 23 is moved to the proximal side, which is the image side, the movable lens holding frame 23 comes into contact with the distal end surface of the tubular adjustment member 26 fixed on the slit 21b of the cylindrical portion 21a, and the image side Movement to the base end side is restricted. The detailed configuration of the adjustment member 26 will be described in detail later.

  As described above, in the present embodiment, the movable range of the movable lens holding frame 23 in the optical axis O direction is such that the arm portion 23 b has the base end surface of the convex portion 22 a of the object side lens holding frame 22 and the distal end surface of the adjustment member 26. It is determined by the range until it contacts.

  A columnar core metal 25 that protrudes toward the distal end side is fitted into the distal end side surface of the arm portion 23b so that an axis Z substantially parallel to the optical axis O becomes the central axis. The core metal 25 is fixed to the arm portion 23b by adhesion, press fitting, or the like.

  The cored bar 25 is provided at a position where the cored bar 25 enters the concave portion 22c provided in the flat portion on the base end side of the convex portion 22a of the object side lens holding frame 22. The cored bar 25 is a part for preventing buckling of the first spring 31 that is an urging member constituting the actuator 30 described later.

  Inside the cylindrical portion 21a of the fixed frame 21, an image side lens holding frame 24 is fixed to the base end side of the movable lens holding frame 23 and the object side of the most advanced fixed lens 11a serving as a cover glass. Yes. The image-side lens holding frame 24 is a substantially cylindrical member that holds the fixed lens 11a of the objective lens 11 that is positioned on the image side (tele end position) with respect to the movable lens 11b.

  On the proximal end side of the fixed frame 21, the periphery of the image sensor 12, the circuit board 14, and the electric cable 115 is surrounded by a cylindrical shield frame 15 made of a thin metal plate. An electrically insulating sealing resin 16 is filled.

  And the circumference | surroundings of the front-end | tip part of the shield frame 15 and the electric cable 115 are coat | covered with the heat contraction tube 17. FIG.

  The movable lens holding frame 23 of the lens barrel portion 20 described above is driven back and forth in the direction of the optical axis O by the actuator 30 disposed on the side portion of the lens barrel portion 20.

  Here, the configuration of the actuator 30 of the present embodiment will be described in detail below.

The actuator 30 here has a configuration for driving the movable lens holding frame 23 in the direction of the optical axis O by expansion and contraction of the SMA wire 36.

  As described above, in the actuator 30, the guide pipe 33 is a cylindrical pipe, and the tip portion is fixed to the holding portion 21 c in a state where the tip portion is inserted into the through hole provided in the holding portion 21 c of the fixed frame 21. Yes.

  The guide pipe 33 is positioned and fixed on the side of the fixed frame 21 along the axis Z, which is the longitudinal center axis, by the holding portion 21c so that the center axis is substantially parallel to the optical axis O.

  An outer tube 35 is connected to the proximal end of the guide pipe 33. The first outer tube 35 is a pipe made of a synthetic resin such as polyether / ether / ketone resin (PEEK).

  An SMA wire 36 is inserted into the outer tube 35. The outer tube 35 is covered with a heat shrinkable tube 56 that integrally covers the proximal end portion of the guide pipe 33.

  The first outer tube 35 can be bent along the curve of the bending portion 109 of the insertion portion 102 of the endoscope 101, and is configured to resist the tension applied to the SMA wire 36 inserted therein. Yes.

  In the guide pipe 33, a piston-like pressing portion 32 is slidably disposed in the axis Z direction. The pressing portion 32 protrudes in the tip direction from the tip of the guide pipe 33.

  The guide pipe 33 is provided with a pressing cap 32 a that is a contact portion that directly contacts the arm portion 23 b of the movable lens holding frame 23 at the distal end portion. The distal end of the expanding and contracting SMA wire 36 is fixed to the pressing cap 32a.

  A second spring 34 that urges the pressing portion 32 toward the distal end is disposed in the guide pipe 33. In the present embodiment, the second spring 34 is a compression coil spring.

  Therefore, when no tension is applied to the SMA wire 36, the pressing cap 32a provided at the distal end of the pressing portion 32 causes the arm portion 23b of the movable lens holding frame 23 to move in the distal direction by the urging force of the second spring 34. Press to.

  That is, the pressing cap 32a that is a contact portion directly contacts the arm portion 23b that is a protruding pattern of the movable lens holding frame 23. Thereby, transmission loss of the driving force of the actuator 30 is reduced.

  The first spring 31, which is an urging member, is disposed so as to urge the movable lens holding frame 23 in the proximal direction along the axis Z. In the present embodiment, the first spring 31 is a compression coil spring and is disposed in a concave portion 22 c provided in the convex portion 22 a of the object side lens holding frame 22.

  Accordingly, the first spring 31 is disposed on the opposite side of the pressing portion 32 with the arm portion 23b of the movable lens holding frame 23 interposed therebetween.

  Here, the first spring 31 has a force that biases the arm portion 23b in the proximal direction along the axis Z, and a force that biases the arm portion 23b in the distal direction along the axis Z by the second spring 34. Also configured to be weak. Therefore, when the SMA wire 36 is extended, the arm portion 23b moves in the distal direction so as to be in the state shown in FIG. 4 by the urging force of the second spring 34, and comes into contact with the convex portion 22a.

  That is, when the SMA wire 36 is not contracted, the movable lens holding frame 23 is positioned at the tip of the movable range. In addition, when the SMA wire 36 contracts and the second spring 34 contracts, and the pressing cap 32 a and the pressing portion 32 move along the axis Z in the proximal direction, the arm portion 23 b biases the first spring 31. To move to the proximal side along the axis Z (see FIG. 5).

  That is, the pressing portion 32 is configured to move forward and backward on the axis Z along the optical axis O direction in accordance with a change in the tension of the SMA wire 36, and the movable lens holding frame by the urging force of the first spring 31. 23 is moved along an optical axis O parallel to the axis Z. The SMA wire 36 is configured to contract when the temperature rises.

  In the present embodiment, the SMA wire 36 is configured to be electrically connectable to the power supply unit 120a shown in FIG. 1 via a pair of electric wires (not shown). The current output from the power supply unit 120a is: Applied to the SMA wire 36.

  The SMA wire 36 generates heat in response to an applied current, and contracts in response to the generated heat to apply tension. As described above, the actuator 30 is configured to generate a driving force for driving the movable lens holding frame 23.

  In addition, since the structure of the actuator 30 using the expansion / contraction of such SMA wire 36 is the same as the past, detailed description about another component is abbreviate | omitted.

  In addition, the configuration of the actuator 30 that is a drive mechanism unit is not particularly limited as long as it is disposed on the side of the lens barrel unit 20 and can drive the movable lens holding frame 23 in the optical axis O direction. Absent.

  For example, instead of the actuator 30 that electrically drives the movable lens holding frame 23, the drive mechanism unit uses a lever provided on the operation unit 103 of the endoscope 101 for a wire routed along the electric cable 115. A mechanism for manually driving the movable lens holding frame 23 by pushing and pulling may be used. The actuator 30 may be configured to drive the movable lens holding frame 23 by a linear motor, for example.

  The imaging unit 1 configured as described above has a drive shaft on the same axis Z parallel to the optical axis O and generates a driving force for driving the movable lens holding frame 23 forward and backward. .

  That is, in the imaging unit 1, the pressing portion 32 is moved by the urging shaft of the urging force for urging the movable lens holding frame 23 by the first spring 31 toward the image side base end and the urging force of the second spring 34. The drive shaft for driving the holding frame 23 in the distal direction on the object side is configured to be provided on the same axis Z in the arm portion 23b.

  As a result, the movable lens holding frame 23 is configured so that a rotational moment due to the urging force toward the proximal end by the first spring 31 and the urging force toward the distal end from the pressing portion 32 does not occur during forward and backward movement. . As a result, the movable lens holding frame 23 can be configured so as not to cause a so-called bend that does not move due to being caught when moving forward and backward in the fixed frame 21.

  Next, the configuration of the adjusting member 26 that abuts and restricts the movement of the movable lens holding frame 23 toward the base side, which is the image side, and the state of being fixed to the fixed frame 21 will be described in detail.

  As shown in FIG. 6, the adjustment member 26 is a tubular member that includes a pressing cap 32 a of the pressing portion 32 that moves forward and backward. The adjustment member 26 is placed on a holding base 27 formed so that its outer peripheral portion protrudes from the side peripheral portion of the cylindrical portion 21 a of the fixed frame 21 along the longitudinal direction, and is bonded and fixed by an adhesive 28. .

  As shown in FIG. 7, the holding base 27 on which the adjusting member 26 is disposed is formed so as to protrude in the outer diameter direction, which is the same direction as the holding portion 21c, along the slit 21b formed in the cylindrical portion 21a. .

  The holding base 27 has two rectangular wall portions parallel to the slit 21b, in this case, rectangular parallelepiped walls, and the opposite edges C at the projecting ends of the two wall portions are parallel to the optical axis O. It has become.

  The edge C here is a boundary line between the opposing wall surfaces (side surfaces) of the two wall portions of the holding table 27 along the slit 21b and the protruding end surfaces (upper surfaces in the drawing) of the two wall portions. It is two straight ridgelines.

  Then, as shown in FIGS. 8 to 10, after the adjustment member 26 is placed on the holding table 27 using a jig (not shown), the position is adjusted in the front-rear direction (F-R) and the adhesive 28 is used. It is fixed.

  Specifically, the adjusting member 26 is adjusted in the front-rear direction (F-R) in a state where the outer peripheral surface which is the outer surface is in contact with the two edges C of the holding table 27 and is fixed by the holding table 27 and the adhesive 28. . The fixing position of the adjustment member 26 is a position where the movable lens holding frame 23 (not shown here) contacts the adjustment member 26 at a tele end position that satisfies the optical performance.

  In other words, the adjustment member 26 has a tele end position where the movable lens holding frame 23 stops moving at a position where the distal end surface 26a serving as the contact surface comes into contact with the base end surface of the arm 23b of the movable lens holding frame 23. The position is adjusted in the front-rear direction (F-R) and is fixed to the holding table 27 by the adhesive 28.

  In this state, the adjusting member 26 is in a state in which the outer peripheral surface is in line contact with two parallel edges C of the holding base 27 (contact portion with the edge C shown in the circle d shown in FIG. 10), and is uniquely. It is fixed in a state where the posture along the axis Z parallel to the optical axis O is determined.

  With this configuration, the contact position between the distal end surface 26a of the adjustment member 26, which is the tele end position where the movable lens holding frame 23 stops moving, and the proximal end surface of the arm portion 23b of the movable lens holding frame 23 is accurate. The adjustment member 26 can be attached to the fixed frame 21 easily and easily.

  As a result, the movable lens holding frame 23 disposed in the fixed frame 21 is moved to the axis X direction in the plane including the optical axis O and the axis Z shown in FIGS. Even if the play is caused by a tolerance greater than the clearance set in the orthogonal axis Y direction, the inclination when the movable lens holding frame 23 stops moving at the tele end position is corrected by the adjustment member 26 that contacts the arm portion 23b. The predetermined optical performance can be satisfied.

  Further, like the endoscope 101 of the present embodiment, in particular, the imaging unit 1 built in the distal end portion 110 of the insertion portion 102 is very small, and various components of the imaging unit 1 are very small, It is difficult to ensure the accuracy of each part. For this reason, the fixed frame 21 and the movable lens holding frame 23 are also small in size, and it is difficult to ensure the component accuracy. However, the adjustment member 26 corrects the inclination of the movable lens holding frame 23 when the movement is stopped at the tele end position. can do.

  In the present embodiment, the central axis of the adjustment member 26 is illustrated so as to coincide with the axis X, and such a configuration is desirable. Of course, the adjustment member 26 hinders the forward / backward movement of the pressing portion 32. However, if the distal end surface 26a is in contact with the proximal end surface of the arm portion 23b of the movable lens holding frame 23, the central axis does not necessarily need to coincide with the axis X.

  As described above, the adjustment member 26 fixed to the holding base 27 of the fixed frame 21 is fixed in a state where the outer peripheral surface thereof is in line contact with the two parallel edges C of the holding base 27, so that the adjustment member 26 does not tilt and is accurate. Can be attached.

  As described above, the imaging unit 1 disposed in the endoscope 101 according to the present embodiment can move the movable lens holding frame forward and backward so that predetermined optical performance can be stably obtained even when the imaging unit 1 is miniaturized. It can be set as the structure which can adjust a stop position easily.

  Note that, in the above description, the telephoto state where the photographing magnification is high is more affected by the optical characteristics due to the tilt of the movable lens holding frame 23 than the wide state where the photographing magnification is low. Although the configuration of the adjustment member 26 that suppresses the tilt of the movable lens holding frame 23 is illustrated, the configuration of the movable lens holding frame 23 is corrected when the movement is stopped at the wide end position without being limited thereto. Also good.

  In other words, the objective optical system may be designed so that the position where the movable lens holding frame 23 moves to the base end and stops becomes the wide end, or moves to the distal end side of the movable lens holding frame 23 and stops. The adjustment member 26 may be provided on the distal end side so as to correct the inclination.

  Here, the imaging unit 1 is set to satisfy the optical performance at the wide end position where the movable lens holding frame 23 moves to the front end side and stops at the time of assembly, and then the position of the adjustment member 26 is adjusted. Thus, the telephoto end position where the movable lens holding frame 23 moves to the base end side and stops is adjusted.

(Modification)
The imaging unit 1 provided in the endoscope 101 described in the above embodiment may include configurations of various modifications described below.

(First modification)
FIG. 11 is a partial cross-sectional view showing a state in which the adjustment member of the first modification is fixed to the fixed frame.
As shown in FIG. 11, a tapered surface 29 is formed opposite to the protruding ends of the two wall portions of the holding base 27, and the two tapered surfaces 29 and the outer peripheral surface of the adjustment member 26 are in line contact (circle d in the figure). The line contact (including the points inside) is very good.

  Also in the configuration of this modification, the adjustment member 26 is moved and adjusted in the front-rear (F-R) direction and is fixed to the holding table 27 by the adhesive 28.

  Even in such a configuration, the positions of the adjustment member 26 in the axis X direction and the axis Y direction are uniquely determined, and can be easily fixed to the fixed frame 21.

(Second modification)
FIG. 12 is a perspective view showing a state in which the adjustment member of the second modification is placed on the holding table.
As shown in FIG. 12, the adjusting member 26 may have a hole 26 b as a jig receiving part for hooking a jig or the like on the outer peripheral part when the adjusting member 26 is moved in the front-rear (F-R) direction. In addition, although the hole part 26b here has illustrated circular shape, it may be any shape such as a square shape, and may be a groove, a protrusion, or the like.

  By providing the hole 26b, it is easy to adjust the front-rear (F-R) direction of the adjustment member 26 by hooking a jig or the like, and to easily position the adjustment member 26.

(Third Modification)
FIG. 13 is a perspective view showing a state in which the adjustment member of the third modified example is fixed to the holding base.
As shown in FIG. 13, a recess 27 a may be formed in the extended end portion of the holding base 27 so that the adhesive strength by the adhesive 28 is increased. The concave portion 27 a is formed in a region where the adhesive 28 is bonded.

  When the adhesive 28 enters and cures in the recess 27a, an anchor effect is obtained, and the adhesive force and fixing durability between the adjusting member 26 and the holding base 27 can be improved.

(Fourth modification)
FIG. 14 is a perspective view showing a state in which the adjustment member of the fourth modified example is fixed to the holding base.
As shown in FIG. 14, a bottomed groove 26 c may be formed on the outer peripheral portion serving as the outer surface of the adjustment member 26 so that the adhesive strength by the adhesive 28 is increased. This groove portion 26 c is also formed in an adhesive region by the adhesive 28.

  Similarly to the third modification, the adhesive 28 enters and hardens into the groove portion 26c, whereby an anchor effect is obtained, and the adhesive force and fixing durability between the adjustment member 26 and the holding base 27 can be improved. In addition, by combining the configuration of the present modification and the configuration of the third modification, it is possible to further improve the adhesive force and fixing durability between the adjustment member 26 and the holding base 27.

(Fifth modification)
FIG. 15 is a perspective view illustrating a state in which the adjustment member of the fifth modification is placed on the holding table, and FIG. 16 is a plan view illustrating the adjustment member of the fifth modification and the arm portion of the movable lens holding frame. is there.
As shown in FIG. 15, a convex portion 26 d is provided on the tip end surface 26 a of the adjustment member 26, and the inclination of the arm 23 b of the movable lens holding frame 23 is finely adjusted by adjusting the position around the axis of the adjustment member 26. You may be able to do it.

  Specifically, as shown in FIG. 16, the tilt of the movable lens holding frame 23 can be sufficiently corrected by the contact of the base end surface of the arm portion 23b of the movable lens holding frame 23 with the distal end surface 26a of the adjustment member 26. Then, the adjustment member 26 is fixed so that the convex portion 26 is in the retracted position where it does not contact the arm portion 23b.

  In addition, when the movable lens holding frame 23 is tilted due to component accuracy or the like, the adjustment member 26 is rotated and fixed around the axis so that the convex portion 26d contacts the arm portion 23b at an appropriate position. Fine adjustment of the tilt correction of the lens holding frame 23 in the axis X direction and the axis Y direction can be performed.

(Sixth Modification)
FIG. 17 is a perspective view showing a state in which the adjustment member of the sixth modified example is placed on the holding table.
Note that the convex portion 26d of the adjustment member 26 illustrated in the fifth modified example has a convex surface that is a convex curved surface, so that the finer correction of the tilt of the movable lens holding frame 23 in the axis X direction and the axis Y direction is fine. The configuration can be adjusted.
In addition, the structure of each modification mentioned above can be combined, respectively.

(Seventh Modification)
Hereinafter, FIG. 18 is a partial cross-sectional view showing a state in which the adjustment member of the seventh modified example is fixed to the holding base.
As shown in FIG. 18, the adjustment member 26 may have a configuration in which two tapered surfaces 26 e are formed in the longitudinal direction and are fixed in a state of being in line contact with the holding table 27.

(Eighth modification)
FIG. 19 is a partial cross-sectional view showing a state in which the adjustment member of the eighth modification is fixed to the holding base.
As shown in FIG. 19, the adjustment member 26 has a cross-sectional shape having two corners, and is fixed in a state of line contact with two tapered surfaces 29 formed at the protruding ends of the two wall portions of the holding base 27. It is good also as a structure to be.

(Ninth Modification)
FIG. 20 is a partial cross-sectional view showing a state in which the adjustment member of the ninth modified example is fixed to the holding base.
As shown in FIG. 20, the adjustment member 26 has two tapered surfaces 26 e formed in the longitudinal direction, and is in surface contact with the two tapered surfaces 29 formed at the projecting ends of the two wall portions of the holding base 27. It is good also as a structure fixed by.

(10th modification)
FIG. 21 is a partial cross-sectional view showing a state where the adjustment member of the tenth modification is fixed to the holding base.
As shown in FIG. 21, the adjustment member 26 has one tapered surface 26 e formed in the longitudinal direction, is in surface contact with the tapered surface 29 formed at the protruding end of one wall portion of the holding base 27, and the side surface is held. It is good also as a structure fixed in the state which is in surface contact with the wall surface of the other wall part of the stand 27. FIG.

  The present invention described above is not limited to the above-described embodiments, modifications, and reference examples, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification. An optical unit for an endoscope with such a change is also included in the technical scope of the present invention.

  According to the present invention, it is possible to provide an optical unit and an endoscope that can easily adjust the advancing / retreating stop position of the movable lens holding frame so that predetermined optical performance can be stably obtained at the time of assembly even if it is downsized. it can.

  This application is filed on the basis of the priority claim of Japanese Patent Application No. 2017-092536 filed in Japan on May 8, 2017, and the above disclosure is included in the present specification and claims. Shall be quoted.

Claims (7)

A fixed lens holding frame for holding the fixed lens;
A movable lens holding frame that is arranged to be movable back and forth with respect to the fixed lens holding frame, and holds a movable lens;
An arm provided on the movable lens holding frame and projecting to the outside of the fixed lens holding frame;
A biasing member that biases the arm portion toward the proximal end;
A drive mechanism portion that is disposed on the fixed lens holding frame and presses the arm portion to drive the movable lens holding frame to the distal end side against the biasing force of the biasing member;
A tubular member fixed to a holding base formed on the fixed lens holding frame and abutting on the arm portion in order to adjust the advance / retreat position of the movable lens holding frame;
Comprising
The fixed lens holding frame is formed with a slit through which the arm portion passes,
As the holding base, two rectangular parallelepiped wall portions are formed along the slit,
The optical unit, wherein the tubular member is fixed to two ridgelines that are boundaries between the opposing wall surfaces of the two wall portions and the projecting end surfaces of the two wall portions with an adhesive .   The optical unit according to claim 1, wherein the tubular member has a jig receiving portion for hooking a jig or the like.   The optical unit according to claim 1, wherein the fixed lens holding frame is provided with the holding table having an edge or a tapered surface.   2. The optical unit according to claim 1, wherein an urging shaft of the urging member and a driving shaft of the driving mechanism unit are coaxial.   The optical unit according to claim 4, wherein a central axis of the tubular member is coaxial with the urging shaft and the drive shaft.   2. The optical unit according to claim 1, wherein the tubular member is provided with a convex portion for adjusting an inclination of the movable lens holding frame on a contact surface with which the movable lens holding frame comes into contact.   An endoscope comprising the optical unit according to claim 1.

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