JP2010240035A - Driving mechanism and endoscopic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving mechanism which is miniaturized and drives a lens or the like with high accuracy. <P>SOLUTION: The driving mechanism is provided with: a protection member which protects built-in objects for picking up an object; an actuator which can be extended and contracted; a driving member which is connected to the actuator; a driven member which is engaged with the driving member by friction; a stator which is arranged so as to be along the surface shape of the protection member; and a position detection part which is fixed to the driven member and arranged opposite to the stator. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a drive mechanism and an endoscope apparatus.

  2. Description of the Related Art Conventionally, in an optical apparatus such as a camera or an endoscope apparatus, a driving apparatus that moves a lens or the like along an optical axis in order to suitably form an image of an object is known. As an example of such a driving device, Patent Document 1 describes a driving device that drives the lens barrel forward and backward by an expansion and contraction operation of a piezoelectric element.

  The driving device described in Patent Document 1 includes a driving member that is frictionally engaged with a driven object, a piezoelectric element that has one end fixed to the driving member and the other end fixed to a stationary member, and the like. Piezoelectric element driving means for applying a voltage so that the speed differs from the speed of shrinkage. In addition, the drive device is provided with a sliding piece that operates integrally with the driven object and a fixed detection plate attached to the stationary member, so that the position of the driven object can be detected.

  Conventionally, an encoder has been used as a sensor for measuring the displacement of an object. For example, Patent Document 2 describes an electrostatic encoder including a scale formed on a glass substrate and a sensor head formed on a resin substrate that can move forward and backward with respect to the scale.

JP-A-4-69070 JP 2006-47135 A

  As described above, in the driving device that drives the driven object using the piezoelectric element, the driving member and the driven object are engaged by friction. For this reason, an unintended slip may occur between the driving member and the driven object. In this case, the driving force applied to the piezoelectric element may not match the driving force transmitted to the driven object. At this time, since the positional deviation between the driving member and the driven object occurs, the driving device described in Patent Document 1 requires means for detecting the movement displacement of the driven object.

  However, since the drive device described in Patent Document 1 is configured to detect the position of the driven object using the sliding piece and the fixed detection plate, it is difficult to reduce the size of the device.

  Moreover, since the electrostatic encoder described in Patent Document 2 uses a thick and hard substrate, there is a possibility that the apparatus configuration becomes large when applied to the drive device described above.

Therefore, there has been a demand for a driving device that is miniaturized and that can drive a lens or the like with high accuracy.
Further, there has been a demand for an endoscope apparatus that is reduced in diameter by including a drive device that is miniaturized as described above.

  The drive mechanism according to this embodiment includes a protective member that protects a built-in object for imaging an object, an actuator capable of extending and contracting, a drive member connected to the actuator, and frictionally engaged with the drive member. A position detector having a driven member, a stator arranged along the surface shape of the protection member, and a mover fixed to the driven member and arranged to face the stator; , Are provided.

  Since the stator is arranged so as to follow the surface shape of the protection member, the area occupied by the stator and the mover can be suppressed, and a miniaturized drive mechanism can be provided. In addition, since the area of the stator can be provided wider than before, a drive mechanism with improved positional accuracy of the driven member can be provided.

  The actuator preferably expands and contracts only in one direction.

  In this case, since the expansion / contraction operation is limited to one direction, a more compact drive mechanism can be provided.

The actuator is preferably a piezoelectric actuator.
In this case, compared with an actuator using a shape memory alloy, a servo motor, or a hydraulic cylinder, voltage control is easier, so a highly accurate drive mechanism can be provided.

Moreover, it is preferable that the said stator is provided in the plane site | part provided in the outer surface of the said protection member.
In this case, since the protection member and the stator can be stably bonded, it is possible to suppress the separation of the stator from the protection member.

  The stator is preferably provided along the inner surface of the protective member.

  In this case, position detection can be performed from a plurality of angles compared to the case where a stator is provided on a plane. Therefore, it is possible to provide a drive mechanism with higher positional accuracy.

An endoscope apparatus according to this embodiment includes the drive mechanism.
In this case, since the drive mechanism is downsized, the imaging mechanism can be reduced in diameter.
A measuring unit that measures a displacement amount of the stator and the moving element; and a drive control unit that transmits a driving pulse to the actuator, and the driving control unit is measured by the measuring unit. Preferably, the drive pulse to be transmitted next is determined in response to feedback of the displacement amount.
In this case, since the drive pulse to be transmitted next is determined based on the movement displacement amount in the measurement unit, the movement displacement amount can be adjusted with high accuracy.

  According to the drive mechanism of the present invention, it is possible to provide a drive device that is miniaturized and can drive a lens or the like with high accuracy. Moreover, the endoscope apparatus reduced in diameter can be provided by providing the drive device reduced in size as mentioned above.

It is a perspective view which shows the endoscope apparatus carrying the drive mechanism of 1st Embodiment of this invention. It is a perspective view which shows the structure of a part of the endoscope apparatus. It is sectional drawing which shows the structure of a part of the endoscope apparatus. It is a perspective view which shows the structure of a part of the endoscope apparatus. It is a perspective view which shows the structure of a part of the endoscope apparatus. It is a perspective view which decomposes | disassembles and shows the structure shown in FIG. (A) And (B) is a perspective view which shows the structure of a part of the endoscope apparatus. (A) And (B) is a side view which shows the operation | movement at the time of use of the same endoscope apparatus. It is a side view which shows the modification of the same endoscope apparatus. It is a perspective view which shows the structure of a part of endoscope apparatus of 2nd Embodiment of this invention. It is a perspective view which shows the structure of a part of the endoscope apparatus. It is a perspective view which shows the operation | movement at the time of use of the same endoscope apparatus.

The drive mechanism according to the present embodiment includes a protection member that protects a built-in object for imaging an object. Further, the actuator includes an actuator capable of extending and contracting, a driving member connected to the actuator, and a driven member frictionally engaged with the driving member.
And a position detector having a stator arranged along the surface shape of the protection member, and a mover fixed to the driven member and arranged facing the stator. Yes.

In this case, since the stator is arranged so as to follow the surface shape of the protective member, the area occupied by the stator and the mover can be suppressed, and a miniaturized drive mechanism can be provided. In addition, since the area of the stator can be provided wider than before, a drive mechanism with improved positional accuracy of the driven member can be provided.
The built-in object for imaging the target object may be not only an optical system and a solid-state imaging element described later, but also temperature detection means such as a light emitting element and a thermistor.

  In the first embodiment to be described later, a frame 71 of the imaging optical unit 70 is shown as a protective member. That is, the stator 64 is provided on a planar portion (planar seat) 71a provided on the outer surface of the frame 71, and the frame 71 and the stator 64 can be stably bonded. Therefore, it is possible to suppress the separation of the stator 64 from the frame 71.

  In a second embodiment to be described later, a cap 32 is shown as a protective member. That is, the stator 164 is provided along the inner surface of the cap 32, and the position of the mover 165 is detected from a plurality of angles as compared with the case where the stator is provided on a planar portion. Can do. Therefore, it is possible to provide a drive mechanism with higher positional accuracy.

The protective member is not limited to the frame 71 and the cap 32, and may be any member as long as the positional relationship is fixed with respect to the driven member. For example, you may arrange | position a stator so that the surface shape of case 31 may be followed. That is, if a stator is provided in the groove 31b provided in the case 31 and a slider is provided in the protrusion 63e provided in the support portion 63b, the movable element of the slider is maintained while maintaining the positional relationship between the stator and the slider. This is preferable because position detection can be performed.
(First embodiment)
Hereinafter, a drive mechanism and an endoscope apparatus according to a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view showing an endoscope apparatus equipped with the drive mechanism of the present embodiment. As shown in FIG. 1, an endoscope apparatus 1 includes a sheath 2 that extends from a proximal end toward a distal end, an imaging mechanism 3 that is disposed at the distal end of the sheath 2 and photographs an object, and a sheath 2. A bending drive unit 3a disposed on the proximal end side of the imaging mechanism 3 to bend the sheath 2, and an operation unit 4 disposed on the proximal end of the sheath 2 to bend the bending drive unit 3a. And a main body 5 extending from the operation section 4 to the proximal end side and connected thereto.

  Although not shown in detail, the sheath 2 is formed in a flexible cylindrical shape, and a wiring path extending from the operation unit 4 and the main body 5 to the imaging mechanism 3 and the bending drive unit 3a is inserted therein.

  The operation unit 4 is provided with a joystick 4a for a user to input a bending direction in order to bend the bending driving unit 3a. In the endoscope apparatus 1 of the present embodiment, the direction in which the joystick 4a is tilted with respect to a predetermined neutral position is input to the main body 5 as the direction in which the bending drive unit 3a is bent. In the main body 5, the bending drive unit 3a is bent based on the input from the joystick 4a.

  The main body 5 includes a display 5 a for displaying an image acquired by the imaging mechanism 3.

  FIG. 2 is a perspective view showing a part of the configuration of the endoscope apparatus 1, and shows the configuration of the imaging mechanism 3 in an exploded manner. FIG. 3 is a perspective view showing a partial configuration of the imaging mechanism 3. FIG. 4 is a cross-sectional view of the imaging mechanism 3. As shown in FIGS. 2 to 4, the imaging mechanism 3 is fixed to the case 31 fixed to the distal end of the sheath 2 shown in FIG. And a cap 32.

  A predetermined optical axis L is set in the imaging mechanism 3. Along the optical axis L, a cover glass 32a provided on the cap 32, a movable optical system 81 capable of moving back and forth along the optical axis L, and a positional relationship with respect to the cover glass 32a are fixed. The imaging optical unit 70 is arranged in this order. In the present embodiment, the cover glass 32a is a glass plate formed in a disk shape.

  The moving optical system 81 is for adjusting the focal length when the light incident from the cover glass 32a is guided to the imaging optical unit 70 to focus on the object to be imaged. In the present embodiment, a convex lens is disposed in the moving optical system 81.

  The imaging optical unit 70 includes an imaging lens group 82 having optical members 82 a and 82 b arranged in a frame 71, and a solid-state image sensor 72 that receives light emitted through the imaging lens group 82. (See FIG. 4). An optical image incident from the cover glass 32 a via the moving optical system 81 is imaged at a predetermined imaging position in the solid-state image sensor 72. Further, the imaging optical unit 70 is disposed with a positional relationship fixed with respect to the case 31.

  Although not shown in detail, a well-known CCD or CMOS area image sensor can be appropriately employed as the solid-state image sensor 72. Moreover, the solid-state image sensor 72 is electrically connected to the main body 5 shown in FIG. 1, and an image captured by the solid-state image sensor 72 is displayed on the display 5a.

  The imaging mechanism 3 includes a drive mechanism 60 for moving the moving optical system 81 forward and backward. The drive mechanism 60 includes a drive member 61 extending along the central axis O1, a piezoelectric actuator 62 connected to the drive member 61 and capable of extending and contracting in the direction of the central axis O1, and a driven member frictionally engaged with the drive member 61. An object 63 and a position detection unit 66 that detects a relative movement distance between the driven object 63 and the imaging optical system 71 are provided.

  The drive member 61 is formed in a cylindrical shape having a generatrix along the central axis O1. The drive member 61 is inserted through a hole 31a formed in the case 31, and is supported with the distal end 61a of the drive member 61 directed toward the distal end and the proximal end 61b of the drive member 61 directed toward the proximal end. Yes. A driven object 63 is frictionally engaged with the outer peripheral surface of the driving member 61.

The piezoelectric actuator 62 has a first end 62a and a second end 62b, and is fixed to the driving member 61 at the first end 62a. The piezoelectric actuator 62 uses a piezoelectric element such as a piezoelectric element, and is an actuator that operates by applying a voltage to the piezoelectric element.
Since the piezoelectric actuator 62 is easier to control the voltage than an actuator using a shape memory alloy, a servo motor, or a hydraulic cylinder, a highly accurate drive mechanism can be provided.
Further, the operation direction of the actuator is preferably one that expands and contracts in only one direction, and a more compact drive mechanism can be provided.

  Although not shown in detail, the piezoelectric actuator 62 has a second end 62b as a fixed end, and a positional relationship between the second end 62b and the case 31 is fixed. Therefore, when the piezoelectric actuator 62 expands and contracts, the first end 62a of the piezoelectric actuator 62 vibrates in the direction of the central axis O1 with the second end 62b as a fixed end. Although details are not shown, the piezoelectric actuator 62 is electrically connected to the main body 5 through the inside of the sheath 2 shown in FIG. 1, and is expanded and contracted by the drive control unit 50 a in the control unit 50.

  As shown in FIG. 3, the driven object 63 includes a friction engagement portion 63 a that frictionally engages the driving member 61, one end fixed to the driven object 63, and the other end facing the outer peripheral surface of the driving member 61. It has the elastic part 63c extended. The other end of the elastic portion 63c is provided with an attachment 63d that is frictionally engaged with the driving member 61 and fitted into the friction engaging portion 63a. The driven object 63 and the driving member 61 are relatively movable along the central axis O1.

  The driven object 63 is formed with a support portion 63b that supports the moving optical system 81, and the positional relationship between the driven object 63 and the moving optical system 81 is fixed. Further, a protrusion 63e is formed on the support portion 63b, and the protrusion 63e can be slidably fitted in a groove 31b formed in the case 31 in the direction of the central axis O1 (see FIG. 2).

Below, the structure of the position detection part 66 of this embodiment is demonstrated with reference to FIGS.
As shown in FIGS. 3 and 4, the position detection unit 66 is fixed to the stator 64 and the driven object 63 that are arranged with the positional relationship fixed to the second end 62 b of the piezoelectric actuator 62. And a movable element 65 which is disposed so as to face the stator 64 and is movable relative to the stator 64 in the direction of the central axis O1.

  The stator 64 is fixed to the imaging optical unit 70. As described above, the imaging optical unit 70 is fixed to the case 31, and the positional relationship between the second end 62b of the piezoelectric actuator 62 and the case 31 is fixed. For this reason, the relative positional relationship of the stator 64 with respect to the second end of the piezoelectric actuator 62 is fixed when the imaging mechanism 3 is assembled. In addition, the stator 64 includes a flexible substrate having flexibility, and includes a wiring path 64a extending in the proximal end direction.

  The mover 65 is fixed to a pedestal 63 f formed on the driven object 63. Further, the moving element 65 has a wiring path 65a that extends once in the distal end direction, then is folded back in the proximal end direction, and extends toward the proximal end side. The mover 65 includes a flexible substrate having flexibility.

  FIG. 5 is a perspective view showing the imaging optical unit 70 and the stator 64. FIG. 6 is an exploded perspective view showing the imaging optical unit 70 and the stator 64. As shown in FIGS. 5 and 6, in the imaging optical unit 70, the frame 71 is formed with a plane seat 71 a for arranging the stator 64 and a flange portion 71 b for positioning with respect to the case 31. Yes. The shape of the plane seat 71a is a shape in which a part of the outer peripheral surface of the frame 71 is removed by leaving an optical path for forming an optical image on the solid-state imaging device 72 in the imaging lens group 82.

  FIG. 7A is an enlarged bottom view showing the stator 64. As shown in FIG. 7A, the stator 64 is formed on the surface on the side facing the moving element 65 and extends in the direction of the central axis O1 (AB direction in the figure). The receiving coupling electrodes 641a, 641b, 641c, The receiving coupling electrode 641 having 641d, and the finger-like electrodes 642 provided from the receiving coupling electrode 641 at predetermined intervals in the direction orthogonal to the AB direction in the figure. The reception coupling electrode 641 and the finger electrode 642 constitute a scale that serves as a reference for the relative position with respect to the moving element 65.

  Although not shown in detail, the reception coupling electrode 641 extends along the wiring path 64a and is electrically connected to the measurement unit 50b provided in the main body 5 shown in FIG.

  The finger electrodes 642 are provided by being classified into four finger electrodes 642a, 642b, 642c, and 642d, and three sets are arranged in this order from the A to the B direction in the figure, and a total of twelve are provided. The finger electrodes 642a, 642b, 642c, 642d are electrically connected to the reception coupling electrodes 641a, 641b, 641c, 641d, respectively. Part of the finger electrodes (for example, the finger electrodes 642b and 642c) is connected to the reception coupling electrodes 641b and 641c through the through holes 643b and 643c in a layer different from the layer where the reception coupling electrode 641 is disposed. ing.

  FIG. 7B is an enlarged top view showing the mover 65. As shown in FIG. 7, the mover 65 applies an AC voltage to the transmission coupling electrodes 651 a and 651 b provided facing the reception coupling electrode 641 and to the transmission coupling electrodes 651 a and 651 b via a wiring (not shown). Voltage applying means 652 to be applied. In the present embodiment, the voltage application unit 652 is provided in the control unit 50.

  The transmission coupling electrodes 651a and 651b function as sensor heads that cause a potential change in the reception coupling electrode 641 in accordance with a change in the relative positional relationship with the finger electrode 642.

  In the position detection unit 66 of this embodiment, when an AC voltage is applied to the transmission coupling electrode 651, the electric field generated in the vicinity of the transmission coupling electrode 651 is received by the finger electrode 642. When the transmission coupling electrode 651 is moved relative to the finger electrode 642, the relative positional relationship between the transmission coupling electrode 651 and the finger electrode 642 changes, and the state of the electric field received by the finger electrode 642 changes. Change.

  At this time, the change in the electric field received at the finger electrode 642 is detected by the measuring unit 50b as the change in the potential at the reception coupling electrode 641. As described above, the position detection unit 66 is configured to measure the relative movement distance of the transmission coupling electrode 651 relative to the finger electrode 642 with reference to a predetermined reference position of the stator 64 where the finger electrode 642 is disposed. . In the present embodiment, the reference position is set at a position where the driven object 63 is closest to the base end 61b in the movable range of the driving member 61.

The operation of the drive mechanism 60 and the endoscope apparatus 1 according to the present embodiment configured as described above will be described with reference to FIGS. 4 and 8.
As shown in FIG. 4, in the endoscope apparatus 1 of the present embodiment, an optical image is incident from the cover glass 32 a toward the solid-state image sensor 72. The moving optical system 81 moves forward and backward along the optical axis L between the cover glass 32 a and the solid-state image sensor 72 in order to form an incident optical image on the solid-state image sensor 72 suitably. Preferably, the optical image is positioned at a target position where the optical image is formed. As described above, the moving optical system 81 is fixed to the driven object 63, and the relative movement between the driven object 63 and the imaging optical unit 70 is performed by the driving mechanism 60.

  In order to move the driven object 63 to the base end 61b side of the drive member 61, a first drive pulse for vibrating the piezoelectric actuator 62 is applied in the drive control unit 50a shown in FIG.

  The waveform of the first drive pulse is set so that the speed of extending the piezoelectric actuator 62 is relatively high and the speed of contracting the piezoelectric actuator 62 is relatively slow. For this reason, when the piezoelectric actuator 62 is extended, the driving member 61 and the driven object 63 are resisted against the frictional force generated between the friction engagement portion 63 a and the attachment 63 d of the driven object 63 and the driving member 61. Are slid and moved. At this time, the driving member 61 is linearly moved to the distal end side along the central axis O1, but the position of the driven object 63 is located at substantially the same position as the position before the driving member 61 is linearly moved. Yes.

Subsequently, the piezoelectric actuator 62 is contracted. At this time, since the contraction speed of the piezoelectric actuator 62 is relatively slow, the driving member 61 and the driven object 63 are integrated with each other by the frictional force generated between the frictional engagement portion 63 a and the attachment 63 d and the driving member 61. Moved to.
Therefore, when the first driving pulse is applied to the piezoelectric actuator 62, the driven object 63 is moved toward the base end 61b by a certain width along the central axis O1 with the expansion and contraction of the piezoelectric actuator 62 as one unit. Moved to.

  Conversely, in order to move the driven object 63 toward the tip 61 a side of the drive member 61, the drive controller 50 a applies a second drive pulse having a waveform different from that of the first drive pulse to the piezoelectric actuator 62.

  The waveform of the second drive pulse is set so that the speed of extending the piezoelectric actuator 62 is relatively slow and the speed of contracting the piezoelectric actuator 62 is relatively fast. Therefore, contrary to the driving by the first driving pulse described above, when the piezoelectric actuator 62 is extended, the driving member 61 and the driven object 63 are linearly moved integrally. Further, when the piezoelectric actuator 62 is contracted, the driven object 63 is located at substantially the same place as before the piezoelectric actuator 62 contracts.

  In this way, the driven object 63 is moved back and forth along the central axis O1 of the driving member 61 by the drive mechanism 60, and the moving optical system 81 fixed to the driven object 63 is moved back and forth along the optical axis L. .

  At this time, since the drive member 61 and the driven object 63 are engaged by friction, the amount of movement per drive pulse may change due to various external factors that cause the frictional force to fluctuate. For this reason, in the driving mechanism 60, the position detection unit 66 detects the relative movement distance between the driving member 61 and the driven object 63, and the position of the driven object 63 on the driving member 61 is determined.

  8A and 8B are side views showing the operation of the position detector 66 in the present embodiment. As shown in FIGS. 8A and 8B, the stator 64 is fixed to the frame 71 of the imaging optical unit 70, and the mover 65 is fixed to the base 63 f of the driven object 63. For this reason, the relative movement between the imaging optical unit 70 and the driven object 63 is interlocked with the relative movement between the stator 64 and the movable element 65.

  The imaging optical unit 70 and the driven object 63 move relative to each other along the central axis O1 of the driving member 61 shown in FIG. At this time, the relative positional relationship between the stator 64 and the mover 65 also changes along the central axis O1.

  An AC voltage is applied to the transmission coupling electrode 651 from the voltage applying unit 652. For this reason, an electric field (not shown) based on the AC voltage is generated in the vicinity of the transmission coupling electrode 651.

  Further, each of the finger electrodes 642 arranged to face the transmission coupling electrode 651 receives an electric field from the transmission coupling electrode 651 by electrostatic action, and has a potential corresponding to the position of the transmission coupling electrode 651. Has occurred.

  When there is no change in the relative position between the stator 64 and the mover 65, the electric field received by the finger electrode 642 does not change. Accordingly, the change in potential is not detected in the measurement unit 50b connected through the reception coupling electrode 641, and it is determined that the stator 64 and the mover 65 are not relatively moved.

  When the imaging optical unit 70 and the driven object 63 are relatively moved, the stator 64 and the mover 65 are relatively moved in the AB direction shown in FIG. 8B. For example, when the mover 65 is moved in the B direction shown in FIG. 8B with respect to the stator 64, the transmission coupling electrode 651 provided on the mover 65 is a finger electrode 642a provided on the stator 64. Toward and away from the finger electrode 642d. Then, in the finger electrode 642 that receives the electric field generated in the transmission coupling electrode 651, the potential varies according to the change in the distance from the transmission coupling electrode 651. The fluctuation of the potential is counted by the measuring unit 50b in the control unit 50, and measured as a moving distance from the reference position.

  The distance that the driven object 63 actually moved by the expansion and contraction of the piezoelectric actuator 62 is measured by the measuring unit 50b. The drive control unit 50a receives the feedback of the travel distance information measured by the measurement unit 50b, and applies a drive pulse to the piezoelectric actuator 62 so that the driven object 63 reaches the target position. Further, the drive control unit determines a drive pulse to be applied next based on the information on the movement distance measured by the measurement unit 50 b and drives the piezoelectric actuator 62.

  When the driven object 63 reaches the target position, the application of the drive pulse in the drive controller 50a is stopped, and the driven object 63 and the moving optical system 81 fixed to the driven object 63 are stopped at the target position. At this time, the moving optical system 81 is in a position where an optical image is suitably formed on the solid-state imaging device 72.

  As described above, according to the driving mechanism 60 and the endoscope apparatus 1 of the present embodiment, the amount of movement of the driven object 63 when the driven object 63 is advanced and retracted on the driving member 61 by the piezoelectric actuator 62 is the position. It is measured by the detection unit 66. For this reason, even if an unintended positional relationship shift occurs between the driven object 63 frictionally engaged and the drive member 61, the movement amount can be measured including this shift.

  In addition, since the change in the electric field generated based on the electrostatic action between the stator 64 and the mover 65 is detected as a potential difference in the measurement unit 50b, the relative movement amount between the stator 64 and the mover 65 is detected. High resolution for measuring. Furthermore, since the movement amount is measured by the change in the electric field, the measurement accuracy of the movement amount is kept high even when the surrounding temperature environment changes. For this reason, even when the endoscope apparatus is used in a high temperature environment, it is possible to suppress the occurrence of a measurement failure as in the related art.

  In addition, since the stator 64 and the mover 65 are formed of a flexible substrate, the position detection unit 66 can be configured to be thin. As a result, the drive mechanism 60 can be configured in a small size, and the position detection unit 66 can be disposed at a place where the internal space is limited like the imaging mechanism 3 of the endoscope apparatus 1. Further, since the drive mechanism 60 is downsized, it is possible to provide an endoscope apparatus in which the imaging mechanism 3 has a reduced diameter.

(Modification 1)
Below, the drive mechanism of 1st embodiment and the modification of an endoscope are demonstrated.
In this modification, a calibration mechanism is provided for calibrating a position that is a reference for measurement of the relative movement distance between the driven object 63 and the imaging optical unit 70 (see FIG. 4 below).
In the present modification, as in the first embodiment described above, the positional relationship in which the driven object 63 is positioned closest to the proximal end 61b of the driving member 61 is set as the reference position.

  When setting the reference position, the first drive pulse is applied only for a predetermined time for the driven object 63 to surely move to the base end 61b side. For example, a time obtained by adding a predetermined time to the time when the driven object 63 is moved from the distal end 61a side to the proximal end 61b side of the driving member 61 can be used as the predetermined time.

  In this modification, the calibration mechanism is configured in the control unit 50, and the control unit 50 transmits a control signal for applying the first drive pulse to the drive control unit 50a for a predetermined time. Subsequently, the calibration is performed by resetting the movement distance information stored in the measurement unit 50b in the control unit 50 after a predetermined time has elapsed.

  Even if the reference position is set in this way, the reference position can be set as in the first embodiment, and the reference position can be calibrated even when the drive mechanism and the endoscope apparatus are in use.

(Modification 2)
Hereinafter, another modification of the drive mechanism and the endoscope apparatus of the first embodiment will be described with reference to FIG.
FIG. 9 is a side view showing a partial configuration of the drive mechanism in the endoscope apparatus of the present modification. As shown in FIG. 9, in this modification, an elastic member 63g is interposed between the base 63f of the driven object 63 and the mover 65.

  The elastic member 63g has a biasing force that biases the moving element 65 from the base 63f toward the stator 64, and for example, rubber, sponge, leaf spring, or the like can be employed. In this modification, the stator 64 and the mover 65 are in contact. Further, although not shown in detail, this modification has a coating that prevents the finger-like electrode 642 and the transmission coupling electrode 651 from being short-circuited.

  Further, a lubricant that reduces the sliding resistance between the stator 64 and the mover 65 is disposed on the contact surface where the stator 64 and the mover 65 are in contact with each other. The lubricant has a thickness that can prevent peeling of the electrodes disposed on the stator 64 and the mover 65, and a thickness and material that allows the electric field generated by the transmission coupling electrode 651 to reach the reception coupling electrode 641. Preferably there is. Note that the above-described coating and the lubricant may be made of the same material and serve both functions.

  In this modification, since the stator 64 and the mover 65 are in contact with each other, the distance between the finger electrode 642 and the transmission coupling electrode 651 is short. Therefore, the attenuation until the electric field generated in the transmission coupling electrode 651 reaches the finger electrode 642 is small. For this reason, fluctuations in potential can be captured with higher sensitivity.

(Second Embodiment)
Below, the drive mechanism and endoscope apparatus of 2nd Embodiment of this invention are demonstrated with reference to FIGS. 10-12. In each embodiment described below, portions having the same configuration as those of the drive mechanism and endoscope apparatus of the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

  FIG. 10 is a perspective view showing a configuration of a part of an endoscope apparatus on which the drive mechanism of the present embodiment is mounted. FIG. 11 is a perspective view showing a state in which the imaging mechanism in the endoscope apparatus is assembled. As shown in FIGS. 10 and 11, this embodiment is different from the endoscope apparatus 1 of the first embodiment in that an imaging mechanism 103 is provided instead of the imaging mechanism 3.

  The imaging mechanism 103 is different from the imaging mechanism 3 of the first embodiment in that the imaging mechanism 103 includes a case 131 instead of the case 31 and a driving mechanism 160 instead of the driving mechanism 60.

  The drive mechanism 160 includes a position detection unit 166 instead of the position detection unit 66. The position detector 166 differs from the position detector 66 of the first embodiment in the arrangement positions of the stator and the mover. In this embodiment, a stator 164 is provided instead of the stator 64, and a mover 165 is provided instead of the mover 65.

  The stator 164 is curved along the inner wall surface of the cap 32. Although not shown in detail, the stator 164 is fitted to the cap 32 and the positional relationship is fixed. When the imaging mechanism 3 is assembled, the stator 164 and the imaging optical unit 70 are in a positional relationship. It is fixed. Also. As in the first embodiment, the positional relationship between the imaging optical unit 70 and the second end 62b of the piezoelectric actuator 62 is fixed.

  The mover 165 is curved between the moving optical system 81 and the cap 32 in a circular arc shape concentric with the stator 164 and disposed inside the stator 164. The movable element 165 is fixed to a driven object 163 provided in place of the driven object 63. In the present embodiment, the moving element 165 is fixed to a support portion 163b on which the moving optical system 81 is supported. For this reason, the driven object 163 does not include the pedestal 63f.

  Further, it further includes a connecting pin 171c that is inserted into the driven object 163 so as to be able to advance and retreat, and is connected to the imaging optical unit 70. The driven object 163 is supported by both the connecting pin 171c and the driving member 61. It moves forward and backward along the central axis O1.

  In the present embodiment, similarly to the first embodiment, both the stator 164 and the mover 165 are configured to have a flexible flexible substrate. Further, the stator 164 is provided with a scale having a receiving coupling electrode 1641 and a finger electrode 1642 as in the first embodiment. Further, the moving element 165 is provided with transmission coupling electrodes 1651a and 1651b similar to those in the first embodiment, thereby constituting a sensor head.

  In the present embodiment, it is preferable that there is an appropriate clearance between the stator 164 and the mover 165. This is because the stator 164 and the movable element 165 collide when the driven object 163 swings with respect to the central axis O1 of the driving member 61 due to the vibration of the driving member 61 accompanying the expansion and contraction of the piezoelectric actuator 62. This is to suppress the meshing.

  FIG. 12 is a perspective view showing the operation of the drive mechanism 160 of this embodiment. Also in this embodiment, the drive member 61 vibrates in the direction of the central axis O1 by the expansion and contraction of the piezoelectric actuator 62. At this time, the driven object 163 is moved back and forth on the driving member 61 based on the driving pulse, similarly to the driven object 63 of the first embodiment.

  Here, since the stator 164 is fixed to the cap 32 (see FIG. 10), the relative movement amount of the driven object 163 with respect to the second end 62b of the piezoelectric actuator 62 is the relative movement amount of the movable element 165 with respect to the stator 164. Is equal to

  Since the relative movement amount between the stator 164 and the mover 165 is measured by the measuring unit 50b as in the first embodiment, the driven object 163 is based on the relative move amount between the stator 164 and the mover 165. The relative movement amount is detected.

  Also in this embodiment, the position detector 166 measures the amount of movement of the driven object 163 when the driven object 163 is moved forward and backward on the driving member 61 by the piezoelectric actuator 62 as in the first embodiment. For this reason, even if an unintended positional relationship shift occurs between the driven object 163 frictionally engaged and the drive member 61, the movement amount can be measured including this shift.

  In addition, the stator 164 and the mover 165 are flexible because they are configured with a flexible substrate. For this reason, it is easy to arrange in a shape that follows the curve of the inner wall of the cap 32, and a miniaturized drive mechanism can be configured by efficiently using the inside of the imaging mechanism 103. Thereby, the diameter of the endoscope apparatus can be reduced.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, in the first embodiment, an example in which the scale is configured in the stator 64 and the sensor head is configured in the moving element 65 is shown, but the configuration of the present invention is not limited to this. For example, even if a sensor head is formed on the stator 64 and a scale is formed on the mover 65, the same effect as the present invention can be obtained.

  In the first embodiment, the configuration in which four finger electrodes 642 from finger electrodes 642a to 642d are provided is shown, but the number and arrangement of the finger electrodes are not limited to this, and the driven object It can be increased or decreased according to the amount of movement.

In the first embodiment, the configuration including the four reception coupling electrodes 641a, 641b, 641c, and 641d is shown. However, it is sufficient that at least two reception coupling electrodes are provided. What is necessary is just to comprise the ring electrode as a pair.
Note that it is preferable to apply the driving mechanism described above to a capsule endoscope because a small image with high image quality can be obtained.

DESCRIPTION OF SYMBOLS 1 Endoscope apparatus 2 Sheath 3, 103 Imaging mechanism 4 Operation part 5 Main body 50 Control part 50a Drive control part 50b Measuring part 60, 160 Drive mechanism 64, 164 Stator (scale)
65,165 Moving element (sensor head)
66,166 Position detection unit 641,1641 Reception coupling electrode 642,1642 Finger electrode

Claims (8)

A protective member for protecting the built-in object for imaging the object;
An actuator that can be extended and contracted;
A drive member connected to the actuator;
A driven member frictionally engaged with the driving member;
A position detector having a stator arranged along the surface shape of the protective member, and a mover fixed to the driven member and arranged to face the stator;
Drive mechanism with   The drive mechanism according to claim 1, wherein the actuator expands and contracts only in one direction.   The drive mechanism according to claim 1, wherein the actuator is a piezoelectric actuator.   The drive mechanism according to any one of claims 1 to 3, wherein the stator is provided on a flat surface provided on an outer surface of the protection member.   The drive mechanism according to any one of claims 1 to 3, wherein the stator is provided along an inner surface of the protection member.   The drive mechanism according to claim 1, wherein the stator and the mover are electrostatic encoders.   An endoscope apparatus comprising the drive mechanism according to any one of claims 1 to 6. A measuring unit that measures the amount of movement displacement between the stator and the mover;
A drive control unit for transmitting a drive pulse to the actuator;
With
8. The endoscope apparatus according to claim 7, wherein the drive control unit determines the drive pulse to be transmitted next in response to feedback of the movement displacement amount measured by the measurement unit.

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