JP5998014B2 - Imaging apparatus and endoscope apparatus - Google Patents

Description

  The present invention relates to an imaging apparatus and an endoscope apparatus.

A general endoscope apparatus is equipped with a pan-focus imaging apparatus capable of focusing from a near point to a far point. This imaging apparatus has a wide focusing range of 6 mm to 100 mm, for example. In recent years, since there is a need to observe a subject in proximity, an endoscope capable of selectively performing normal observation for a long distance object point and proximity observation for a short distance object point as disclosed in Patent Document 1, for example. Has been proposed. In this endoscope, two types of focusing ranges, a near-point focusing range with a shooting distance of 2 to 5 mm and a far-point focusing range with 5 to 100 mm, can be selectively used.
As a lens moving means for moving the lens in the optical axis direction for zooming and focusing, a cam shaft 81 is widely used as shown in a sectional view of the distal end portion of the endoscope in FIG. According to the imaging apparatus shown in FIG. 7, the cam shaft 81 is rotationally driven by the rotational driving force of the motor M being transmitted via the gear 83, the intermediate shaft 85, and the like. The lens holding members 91 and 93 that hold the lenses 87 and 89 are supported by the cam shaft 81 and have pins 99 and 101 that are inserted into the cam grooves 95 and 97, respectively. When the cam shaft 81 is driven to rotate, the pins 99 and 101 move along the cam grooves 95 and 97 in the optical axis direction. As the pins 99 and 101 move, the lenses 87 and 89 held by the lens holding members 91 and 93 move to desired positions in the optical axis direction, respectively.

Japanese Patent No. 4819969

However, when the cam shaft 81 is used as a means for moving the lenses 87 and 89, there is a disadvantage that it is difficult to reduce the size of the imaging apparatus. That is, when the diameter of the cam shaft 81 is reduced, the pins 99 and 101 inserted into the cam grooves 95 and 97 may be fixed to the cam grooves 95 and 97. Further, when the cam shaft 81 is reduced in diameter, the cam grooves 95 and 97 cannot be sufficiently deep.
SUMMARY OF THE INVENTION An object of the present invention is to provide an imaging device that does not use a cam shaft as a lens moving means and is more suitable for downsizing, and thus makes it possible to provide an endoscope device with a smaller diameter.

The present invention has the following configuration.
(1) By moving an optical member arranged on the imaging optical path along the optical axis, either the near-point focusing range for near-field shooting or the far-point focusing range for far-field shooting is focused. An imaging device that switches to a range,
A holding member that holds the optical member movably along the optical axis;
A rotating shaft that is arranged in parallel with the optical axis direction and that moves the optical member along the optical axis by rotational driving;
With
The rotating shaft has a plurality of first magnetic bodies arranged at different axial positions and different circumferential positions on a part of the circumferential surface of the rotating shaft,
The holding member has a second magnetic body that generates a magnetic force between the first magnetic body and a part of the holding member,
An imaging apparatus in which one of the first magnetic body and the second magnetic body face each other by rotational driving of the rotary shaft, and the holding member moves along the optical axis by a magnetic force generated between the magnetic bodies. .
(2) An endoscope apparatus in which the imaging device of (1) is arranged at the distal end portion of the endoscope.

  According to the present invention, an imaging apparatus suitable for further miniaturization can be obtained without using a cam shaft as a lens moving unit. Thereby, an endoscope apparatus with a smaller diameter can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for describing embodiment of this invention, and is sectional drawing which shows schematic structure of the imaging device arrange | positioned at the endoscope front-end | tip part. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. (A) is a far-focus mode in a state where the movable lens is moved to the rear end side, and (B) is an explanatory diagram showing a state of the near-focus mode in a state where the movable lens is moved to the front end side. It is a graph which shows distribution of MTF of the specific frequency by the rectangular chart with respect to the object surface distance to observation object. It is a partial cross section figure which shows the structure of another imaging device. It is a partial cross section figure which shows the structure of another imaging device. It is sectional drawing which shows the structure of the imaging device in the conventional endoscope front-end | tip part.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram for explaining an embodiment of the present invention, and is a cross-sectional view showing a schematic configuration of an imaging apparatus arranged at the endoscope distal end portion.
The imaging apparatus 100 has a function that can be switched to any one of a near-point focus range in which the closest point can be focused and a far-point focus range in which the farthest point can be focused. Have. The imaging device 100 includes an imaging unit 11 and a lens driving unit 13. The imaging unit 11 includes an objective lens 15, a movable lens 17, a triangular prism 19, and a circuit board 23 on which electronic components including an imaging element 21 are mounted.

  The movable lens 17 as an optical member is a lens that switches a focusing range, and is held by a lens holding member 25 so as to be movable along the optical axis of the objective lens 15. The triangular prism 19 bends the optical axis of the movable lens 17 at a right angle on the total reflection surface 19 a so that an optical image is formed on the image sensor 21.

  The circuit board 23 is connected to a flexible circuit board 31 on which an electronic component 27 is mounted and a lead wire 29 is soldered, and signals are exchanged between the image sensor 21 and the outside.

  The lens driving unit 13 is arranged in parallel with the optical axis direction of the movable lens 17 and rotatably supports the rotating shaft 33 that is rotationally driven by a driving unit (not shown), the lens holding member 25, and the rotating shaft 33. A shaft support member 41 having a front end side support portion 37 and a rear end side support portion 39.

  A rotary actuator such as a small motor (not shown) is attached to the rear end connection portion 33a of the rotary shaft 33, and the rotary shaft 33 is driven to rotate to a desired rotational position centered on the axis L. The lens holding member 25 has an insertion hole 35 through which the rotation shaft 33 is inserted, and is supported so as to be movable in the axial direction of the rotation shaft 33. The lens holding member 25 may be configured to move along other shafts and grooves (not shown) instead of the rotating shaft 33. However, the lens holding member 25 is configured to be inserted into the rotating shaft 33 and supported by the shaft. It can be reduced and the configuration can be more suitable for downsizing.

  The rotating shaft 33 has two drive magnets (first magnetic bodies) 43 and 45 arranged at different axial positions and different circumferential positions on a part of its circumferential surface. 2 is a cross-sectional view taken along line AA in FIG. The drive magnet 43 has a tip portion 43a inserted into the drill hole 35b of the rotary shaft 33 and a head portion 43b exposed outside the drill hole 35b. As shown by a dotted line in FIG. 2, in this configuration, the driving magnets 43 and 45 are arranged at a circumferential position (a position at the center angle φ = 180 °) of the rotating shaft 33 every 180 degrees. As shown in FIG. 1, the difference between the axial distance Wm between the head 43b of the pair of driving magnets 43 and the head 45b of the driving magnet 45 and the width Wh of the lens holding member 25 is movable. This is the moving distance of the lens 17 in the optical axis direction.

  The lens holding member 25 is provided with driven magnets (second magnetic bodies) 47 and 49 so as to oppose the projecting and projecting positions of the driving magnets 43 and 45 that appear alternately by the rotation of the rotary shaft 33. The driven magnets 47 and 49 are accommodated in recesses 51 and 53 formed on the side surface of the lens holding member 25 so as not to contact the driving magnets 43 and 45.

  The driving magnets 43 and 45 and the driven magnets 47 and 49 are permanent magnets, respectively, a pair of the driving magnet 43 and the driven magnet 47 facing each other, the driving magnet 45 and the driven magnet 49, The pairs are arranged as pairs in which different polarities attracting each other are exposed to the outside. For example, the driving magnets 43 and 45 are arranged to expose the N pole, and the driven magnets 47 and 49 are arranged to expose the S pole.

Next, the operation of the imaging apparatus 100 having the above configuration will be described.
FIG. 3A shows a far-point focusing range mode in which the movable lens 17 has moved to the rear end side (right side in the figure), and FIG. 3B shows a state in which the movable lens 17 has moved to the front end side (left side in the figure). It is explanatory drawing which shows the mode of the near point focusing range mode. In the following description, the same reference numerals are assigned to the same members, and the description thereof is simplified or omitted.
As shown in FIG. 3A, the rotary shaft 33 is rotationally driven, and the driving magnet 43 is disposed at the lowest point position in the figure. Then, the driven magnet 47 on the side facing the driving magnet 43 is attracted to the driving magnet 43 side by the magnetic force f1, and the lens holding member 25 moves in the direction D1 in the drawing. The movement of the lens holding member 25 toward the back side in the observation direction by the imaging device 100 stops at a position where the end 25c of the lens holding member 25 contacts the head 43b of the driving magnet 43. The stop position of the lens holding member 25 at this time is the position of the movable lens 17 that is in the far-point focusing range mode of the imaging apparatus 100.

  At this time, the driving magnet 45 is arranged at a position far from the driven magnet 49 at the uppermost point in the drawing, so that a magnetic force substantially acts between the driving magnet 45 and the driven magnet 49. Disappear.

  As shown in FIG. 3B, the rotary shaft 33 is rotationally driven from the state of FIG. 3A, and the driving magnet 45 is disposed at the lowest point position in the figure. Then, the driven magnet 49 facing the drive magnet 45 is attracted to the drive magnet 45 side by the magnetic force f2, and the lens holding member 25 moves in the direction D2 in the drawing. The movement of the lens holding member 25 toward the front side in the observation direction by the imaging apparatus 100 stops at a position where the end 25c of the lens holding member 25 contacts the head 45b of the driving magnet 45. The stop position of the lens holding member 25 at this time is the position of the movable lens 17 that is in the near point focusing range mode of the imaging apparatus 100.

  FIG. 4 shows the MTF distribution of a specific frequency according to a rectangular chart with respect to the object distance to the observation target. In the far-point focusing range mode, the contrast is high when the object surface distance is 6 mm or more, and in the near-point focusing range mode, the contrast is high in the range of 2 to 5 mm. Therefore, a high-resolution focused image can always be obtained by setting the near-point focusing range mode when the distance to the observation target is short and setting the far-point focusing range mode when the distance to the observation target is short.

  The rotary shaft 33 may be driven by rotating the endoscope operator by viewing a video image of an observation target displayed on the monitor and outputting a control signal for controlling a rotary actuator such as a small motor by operating a button. Alternatively, the rotation may be performed by connecting a rotating wire to the rotating shaft 33 and rotating the rotating wire by the operator. Further, the distance to the observation target is obtained from the image data of the observation image acquired by the imaging apparatus 100 by the estimation calculation by the control circuit, and the rotation shaft 33 is rotationally driven and controlled by the control circuit according to the estimated distance. Good. The estimation of the distance to the observation target can be obtained from, for example, luminance information of image data and AE information such as an aperture and a shutter speed at the time of image shooting.

  As described above, in the imaging apparatus 100 of the present configuration, the axial position of the movable lens 17 changes every time the rotary shaft 33 rotates 180 degrees, and the far-point focus range mode and the near-point focus range mode. And switch. In addition, since the imaging device 100 is configured such that the movable lens 17 moves using the magnetic force of the permanent magnet as a driving source, it can have a simple and less trouble driving function, and can always be switched to each mode reliably.

  The imaging apparatus 100 having this configuration is configured using the rotating shaft 33 without using the cam shaft shown in FIG. 7, and the lens holding member 25 can be moved in the axial direction even when the rotating shaft 33 is further reduced in diameter. There will be no trouble. Therefore, the image pickup apparatus 100 can be further reduced in size, and the endoscope distal end can be further reduced in diameter.

  The present invention is not limited to the above-described embodiments, and the configurations of the embodiments may be combined with each other, or may be modified or applied by those skilled in the art based on the description of the specification and well-known techniques. The invention is intended and is within the scope of seeking protection.

  For example, as illustrated in FIG. 5, the imaging apparatus 100 sets the driving magnets 43.45 provided on the rotary shaft 33 to have different polarities, and the driven magnets on the lens holding member 25 side face the driving magnets facing each other. The imaging device 100 </ b> A may be configured by a single magnet arranged so that the polarities 43 and 45 have different polarities. In this case, the number of parts can be reduced and the lens holding member 25 can be made thinner.

  Further, as shown in FIG. 6, the imaging apparatus 100 may be provided with auxiliary driving magnets 65 and 67 for applying a repulsive force in addition to providing the driving magnets 43 and 45 similar to those described above on the rotary shaft 33. Good. That is, an auxiliary driving magnet 63 having a polarity different from that of the driving magnet 43 is provided on the circumferential surface of the rotary shaft 33 at the same axial position 180 degrees opposite to the driving magnet 43. The imaging device 100 </ b> B may be provided with an auxiliary driving magnet 65 having a polarity different from that of the driving magnet 45 on the peripheral surface of the rotating shaft 33 on the opposite side of 180 degrees.

  In this case, an attractive force is generated between the driving magnet 43 and the driven magnet 47, and a repulsive force is generated between the auxiliary driving magnet 65 and the driven magnet 49. These suction force and repulsive force simultaneously act on the lens holding member 25 to drive the lens holding member 25 in the same direction. Thereby, switching between the far-point focusing range mode and the near-point focusing range mode can be performed at higher speed. Further, it is possible to reliably prevent the lens holding member 25 from being unintentionally detached from the movement destination position due to external impact or vibration.

  The imaging apparatus has been described as a configuration example of two-stage switching of the depth of field, but can be applied to a configuration that switches to three or more stages. In the case of switching to three stages, the drive magnets may be arranged in the circumferential direction at every central angle of 120 degrees.

  The driving magnet 43 and the driven magnet 47 may be configured such that one of them is a permanent magnet, the other is a ferromagnetic material such as steel, and the rotary shaft 33 is a non-magnetic material. Even in this configuration, the lens holding member 25 can be moved by the magnetic force generated between the permanent magnet and the ferromagnetic material.

The image pickup apparatus of the present invention can be used not only for switching the depth of field but also for switching the zoom position and the focus position as long as they do not depart from the spirit of the invention.
Furthermore, the imaging apparatus of the present invention can be applied not only to an endoscope apparatus but also to other medical equipment and industrial equipment.

As described above, the following items are disclosed in this specification.
(1) By moving an optical member arranged on the imaging optical path along the optical axis, either the near-point focusing range for near-field shooting or the far-point focusing range for far-field shooting is focused. An imaging device that switches to a range,
A holding member that holds the optical member movably along the optical axis;
A rotating shaft that is arranged in parallel with the optical axis direction and that moves the optical member along the optical axis by rotational driving;
With
The rotating shaft has a plurality of first magnetic bodies arranged at different axial positions and different circumferential positions on a part of the circumferential surface of the rotating shaft,
The holding member has a second magnetic body that generates a magnetic force between the first magnetic body and a part of the holding member,
An imaging apparatus in which one of the first magnetic body and the second magnetic body face each other by rotational driving of the rotary shaft, and the holding member moves along the optical axis by a magnetic force generated between the magnetic bodies. .
(2) The imaging apparatus according to (1),
The first magnetic body is a pair of imaging devices arranged at a circumferential position of 180 degrees of the rotating shaft.
(3) The imaging apparatus according to (2),
The image pickup apparatus, wherein the holding member is provided inside an arrangement range in the optical axis direction with respect to the pair of first magnetic bodies.
(4) The imaging apparatus according to any one of (1) to (3),
The imaging device in which at least one of the first magnetic body and the second magnetic body is a permanent magnet.
(5) The imaging device according to (4),
The imaging device in which the generated magnetic force is a magnetic force attracting each other.
(6) The imaging apparatus according to any one of (1) to (5),
The second magnetic body is an imaging device provided at each end of the holding member in the optical axis direction.
(7) The imaging apparatus according to any one of (1) to (6),
The rotating shaft is an imaging device that supports the holding member so as to be movable in the optical axis direction.
(8) An endoscope apparatus in which the imaging apparatus according to any one of (1) to (7) is disposed at an endoscope distal end portion.

DESCRIPTION OF SYMBOLS 11 Image pick-up part 13 Lens drive part 15 Objective lens 17 Movable lens 21 Image pick-up element 25 Lens holding member 33 Rotating shaft 43,45 Drive magnet 47,49 Driven magnet 61 Driven magnet 63,65 Auxiliary drive magnet 100 Imaging device

Claims (8)

By switching the optical member arranged on the imaging optical path along the optical axis, the focus is switched to either the near-point focus range for near-field shooting or the far-point focus range for far-field shooting. An imaging device,
A holding member that holds the optical member movably along the optical axis;
A rotating shaft that is arranged in parallel with the optical axis direction and that moves the optical member along the optical axis by rotational driving;
With
The rotating shaft has a plurality of first magnetic bodies arranged at different axial positions and different circumferential positions on a part of the circumferential surface of the rotating shaft,
The holding member has a second magnetic body that generates a magnetic force between the first magnetic body and a part of the holding member;
The imaging device in which one of the first magnetic body and the second magnetic body face each other by the rotational drive of the rotary shaft, and the holding member moves along the optical axis by a magnetic force generated between the magnetic bodies. . The imaging apparatus according to claim 1,
A pair of the first magnetic bodies are arranged at a circumferential position of every 180 degrees of the rotating shaft. The imaging apparatus according to claim 2,
The image pickup apparatus, wherein the holding member is provided inside an arrangement range in the optical axis direction with respect to the pair of first magnetic bodies. An imaging apparatus according to any one of claims 1 to 3,
An imaging apparatus in which at least one of the first magnetic body and the second magnetic body is a permanent magnet. The imaging apparatus according to claim 4,
The imaging apparatus, wherein the generated magnetic force is a magnetic force attracting each other. An imaging apparatus according to any one of claims 1 to 5,
The second magnetic body is an imaging device provided at each end of the holding member in the optical axis direction. The imaging apparatus according to any one of claims 1 to 6,
The rotating shaft is an imaging device that supports the holding member so as to be movable in the optical axis direction.   An endoscope apparatus in which the imaging apparatus according to any one of claims 1 to 7 is disposed at an endoscope distal end portion.

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