JP2012196344A - Endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to run super-resolution processing on a captured image and acquire a high-resolution image in an endoscope while also adopting a configuration allowing for an insertion part to have a smaller diameter.SOLUTION: Adopted is a configuration comprising: a protective tube forming an insertion part inserted into a subject; a shaft 11 which is passed through the protective tube and is supported by a plurality of spacers 12A-12(E) disposed within the protective tube in the axial direction at a predetermined pitch; a solid-state imaging element 22 mounted onto the distal end-side of the shaft 11; and a piezoelectric actuator 41 for applying driving force to the proximal end-side of the shaft 11 on the outside of the protective tube, to thereby create vibration of the shaft 11 in the lateral direction, the support sites of the plurality of spacers 12A-12(E) serving as nodes therefor.

Description

  The present invention relates to an endoscope that images the inside of a subject that cannot be directly observed from the outside, and more particularly, to a technique for obtaining a high-resolution image in the endoscope.

  2. Description of the Related Art Conventionally, in a rigid endoscope having a highly rigid insertion portion, a configuration is known in which an imaging unit including a solid-state imaging device and a drive circuit board of the solid-state imaging device is provided at the distal end of the insertion portion (patent) Reference 1).

  In this type of endoscope, it is desirable to obtain a finer image using a high-resolution image sensor, but the size of the image sensor is required because of the need for downsizing of the apparatus (particularly, the diameter of the insertion portion). Is restricted by the diameter of the insert. As a technique for obtaining an image with a resolution higher than the number of pixels of the image sensor itself, for example, an optical image formed on the light receiving surface of the image sensor using an actuator composed of a piezo element and the like are relatively There is known a method of generating an image having a resolution higher than the original resolution of the image sensor from a plurality of original images acquired by so-called pixel shift, which is imaged while being slightly displaced (see Patent Documents 2 and 3).

  Further, as an image processing method for generating a high-resolution image from a plurality of original images acquired by pixel shifting, an image shift process for mapping pixel values of a low-resolution image to pixels of a high-resolution image, or an ML (Maximum-likelihood) method A super-resolution technique using a MAP (Maximum A Posterior) method, a POCS (Projection On to Convex Sets) method, or the like is known (see Patent Document 4).

JP 2010-279527 A JP-A-8-65569 JP-A-11-275408 JP 2008-306492 A

  By the way, an endoscope having a small-diameter insertion portion (for example, a tube having an outer diameter of 2 mm) is suitable for nasal pituitary surgery or the like. However, in such an endoscope, there is a problem that the actuators described in Patent Documents 2 and 3 cannot be arranged because the space in the insertion portion is limited. Although it is conceivable to arrange the actuator outside the insertion portion, in the conventional techniques described in Patent Documents 2 and 3, it is not possible to slightly displace the image pickup device arranged at the tip of the insertion portion with high accuracy. There was a problem that it was difficult. Further, when the actuator is disposed outside the insertion portion, the distance between the actuator and the image sensor increases, and therefore, in the conventional techniques described in Patent Documents 2 and 3, the displacement amount of the image sensor can be appropriately ensured. There was also a problem that it was difficult.

  The present invention has been devised in view of such a problem of the prior art, and has a configuration in which the diameter of the insertion portion can be reduced, while performing a super-resolution process on the captured image, thereby obtaining a high-resolution image. The main purpose is to provide an endoscope that can acquire the above.

  The endoscope of the present invention is supported by a protective tube that forms an insertion portion to be inserted into a subject, and a plurality of spacers that are inserted through the protective tube and arranged in the axial direction at a predetermined pitch in the protective tube. The driving force transmission shaft, the image sensor attached to the distal end side of the driving force transmission shaft, and the driving force applied to the base end side of the driving force transmission shaft outside the protective tube, And an actuator that generates a vibration in a lateral direction with a support portion of the plurality of spacers as a node with respect to the transmission shaft.

  As described above, according to the present invention, by applying a driving force from an actuator arranged outside the protective tube to vibrate the driving force transmission shaft, the image sensor attached to the tip side of the driving force transmission shaft is displaced. (I.e., the optical image formed on the light receiving surface of the image sensor and the image sensor are relatively displaced), so that the captured image can be obtained while the diameter of the insertion portion can be reduced. It is possible to obtain a high resolution image by performing super-resolution processing on the image.

A perspective view of endoscope 1 concerning a 1st embodiment. II-II line sectional view in FIG. Typical sectional drawing which shows the structure of 12 A of 1st spacers of the endoscope 1 which concerns on 1st Embodiment. Enlarged view of part IV in Fig. 2 Enlarged view of part V in Fig. 2 Enlarged view of part VI in Fig. 2 The perspective view which abbreviate | omits and shows a part of internal structure of the main-body part 2 of the endoscope 1 which concerns on 1st Embodiment. The partial perspective view of the internal structure of the main-body part 2 in the endoscope 1 which concerns on 1st Embodiment. Bottom view of the internal structure shown in FIG. The perspective view of the (A) board back side and (B) board surface side which show the circumference of light reception sensor 54 in main part 2 of endoscope 1 concerning a 1st embodiment. Operation explanatory diagram at the time of imaging of the endoscope 1 according to the first embodiment FIG. 11 is a diagram for explaining the operation of the endoscope 1 taken along the line XII-XII in FIG. The schematic diagram which shows the mode of the displacement of an image pick-up element at the time of the imaging of the endoscope 1 which concerns on 1st Embodiment. Operation | movement explanatory drawing at the time of imaging of the endoscope 1 which concerns on the modification of 1st Embodiment. Operation | movement explanatory drawing at the time of imaging of the endoscope 1 which concerns on 2nd Embodiment Operation | movement explanatory drawing at the time of imaging of the endoscope 1 which concerns on the modification of 2nd Embodiment ((A) Before operation | movement (B) After operation | movement) Operation | movement explanatory drawing at the time of imaging of the endoscope 1 which concerns on 3rd Embodiment. The schematic diagram which shows the mode of the displacement of an image pick-up element at the time of the imaging of the endoscope 1 which concerns on 3rd Embodiment. The schematic diagram which shows the mode of the displacement of an image pick-up element at the time of the imaging of the endoscope 1 which concerns on the modification of 3rd Embodiment.

  A first invention made to solve the above-mentioned problems is a protective tube that forms an insertion portion to be inserted into a subject, and is inserted through the protective tube and is arranged in the protective tube in the axial direction at a predetermined pitch. A driving force transmission shaft supported by a plurality of spacers, an image sensor attached to the distal end side of the driving force transmission shaft, and applying a driving force to the proximal end side of the driving force transmission shaft outside the protective tube Thus, an actuator for generating a lateral vibration having the support portions of the plurality of spacers as nodes on the driving force transmission shaft is provided.

  According to this, it is possible to displace the image sensor attached to the distal end side of the driving force transmission shaft by applying a driving force from an actuator arranged outside the protective tube to vibrate the driving force transmission shaft. Therefore, it is possible to obtain a high-resolution image by performing super-resolution processing on the captured image, while having a configuration in which the diameter of the insertion portion can be reduced.

  The second aspect of the invention further includes a biasing member that biases the driving force transmission shaft in an initial state between the spacers by biasing the driving force transmission shaft.

  According to this, since the driving force transmission shaft in the initial state is bent between the spacers, the backlash between each spacer and the shaft supported by the spacer is suppressed, and the shaft is attached to the front end side of the driving force transmission shaft. The obtained image sensor can be displaced more stably and with high accuracy.

  According to a third aspect of the present invention, the actuator includes two actuators that apply the driving force in two directions intersecting each other.

  According to this, it is possible to easily change the locus of displacement of the image sensor attached to the tip side of the driving force transmission shaft.

  According to a fourth aspect of the present invention, there is provided a configuration further comprising a position detection sensor that is further fixed to the base end side of the driving force transmission shaft of the actuator in the driving force transmission shaft and detects the position of the driving force transmission shaft. To do.

  According to this, since the degree of freedom of arrangement of the position detection sensor is improved, the displacement amount of the image sensor can be estimated easily and accurately from the displacement amount of the driving force transmission shaft.

  According to a fifth aspect of the present invention, there is provided a protective tube that forms an insertion portion to be inserted into a subject, a driving force transmission shaft that is supported by a plurality of spacers arranged in the axial direction at a predetermined pitch in the protective tube, An imaging device attached to the distal end side of the driving force transmission shaft, an urging member for bending the driving force transmission shaft in an initial state between the spacers by urging the driving force transmission shaft, and the protection An actuator that applies a driving force to the base end side of the driving force transmission shaft outside the tube, thereby causing the driving force transmission shaft to periodically rotate with support portions of the plurality of spacers as fulcrums; It is set as the structure provided with.

  According to this, by applying a driving force from an actuator arranged outside the protective tube and periodically rotating the driving force transmission shaft, the image sensor attached to the distal end side of the driving force transmission shaft is displaced. Therefore, it is possible to obtain a high-resolution image by performing super-resolution processing on the captured image, while having a configuration in which the diameter of the insertion portion can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a perspective view of an endoscope 1 according to an embodiment of the present invention. The endoscope 1 is a rigid endoscope used for medical use and industrial use, and mainly includes a main body portion 2 and an insertion portion 3 extending forward from the main body portion 2. Although not shown, the main body 2 can supply power from a commercial power source or the like via a power cable, and can also transmit image data to an external device (such as an image processing apparatus or a monitor) via a communication cable. And control signals can be transmitted and received. The insertion portion 3 has a relatively small diameter (for example, an outer diameter of 2 mm, an inner diameter of 1.6 mm) and has a high rigidity that does not easily bend, and is inserted into a subject (not shown) (for example, a patient's body). .

  2 is a cross-sectional view taken along the line II-II in FIG. 1, FIG. 3 is a schematic cross-sectional view showing the configuration of the first spacer 12A of the endoscope 1, and FIG. 4 is an enlarged view of a portion IV in FIG. 5 is an enlarged view of a V portion in FIG. 2, and FIG. 6 is an enlarged view of a VI portion in FIG.

  As shown in FIG. 2, the outer shell of the insertion portion 3 is fitted with a protective tube 4 made of a metal circular tube whose rear end portion is fixed to the main body portion 2, and a front end (front end) of the protective tube 4. And a tip cover 6 made of a transparent resin material such as a bottomed cylindrical acrylic. The tip cover 6 functions as an imaging window that transmits light from the subject. In the protective tube 4, the front opening is covered with the tip cover 6, while the rear opening communicates with the inside of the main body 2, thereby defining a sealed internal space of the insertion portion 3.

  A shaft (driving force transmission shaft) 11 that extends forward from the inside of the main body 2 and has the imaging unit 10 attached to the front end is inserted into the protective tube 4 and the tip cover 6. The shaft 11 is a rod-like member made of so-called spring steel and easily elastically deformed, and can be bent from a straight state when a predetermined external force is applied. The protective tube 4 and the main body 2 are supported by a plurality of (here, four) first spacers 12A to 12D arranged in the axial direction at a predetermined pitch. Thus, the shaft 11 is arranged coaxially with the protective tube 4 and the tip cover 6 in a state where no external force is received, and movement in the radial direction is restricted.

  As shown in FIG. 3, the first spacer 12 </ b> A includes a small-diameter annular member 13 in which the shaft 11 is fitted, a large-diameter annular member 14 that surrounds the small-diameter annular member 13, and an outer peripheral portion of the small-diameter annular member 13. A pair of rotating shafts disposed in the x-axis direction (vertical direction) that are interposed between the inner peripheral portion of the large-diameter annular member 14 and allow the small-diameter annular member 13 to be rotatable with respect to the large-diameter annular member 14. 15, 15, and a y-axis direction (left and right) that are interposed between the outer peripheral portion of the large-diameter annular member 14 and the inner peripheral portion of the protective tube 4 and make the large-diameter annular member 14 rotatable relative to the protective tube 4. A pair of rotating shafts 16 and 16 arranged in the direction), thereby forming a gimbal mechanism. That is, the shaft 11 is restricted from moving in the front-rear direction by the first spacer 12A, and can be tilted in any direction with the first spacer 12A as a fulcrum by the gimbal mechanism.

  Further, the second spacer 12B and the third spacer 12C sequentially disposed behind the first spacer 12A are in contact with the inner peripheral surface of the protective tube 4 and the outer peripheral surface of the shaft 11, as shown in FIG. Is provided. The second spacer 12B and the third spacer 12C support the shaft 11 so as to be slidable in the axial direction. Here, the second spacer 12B and the third spacer 12C are made of a synthetic resin annular member having an inner diameter substantially the same as the outer diameter of the shaft 11. However, the present invention is not limited thereto, and is equally spaced in the circumferential direction of the shaft 11. A plurality of (for example, four) support members arranged may be used. Further, in the cross section shown in FIG. 4, the inner peripheral surfaces (contact surfaces with the shaft 11) of the second spacer 12 </ b> B and the third spacer 12 </ b> C have an arc shape that protrudes toward the outer peripheral surface of the shaft 11. As a result, the shaft 11 can easily tilt in any direction with the second spacer 12B and the third spacer 12C as fulcrums.

  Further, as shown in FIG. 5, the fourth spacer 12D disposed in the main body 2 behind the third spacer 12C is made of an annular member having substantially the same configuration as the second spacer 12B and the third spacer 12C. The shaft 11 is slidably supported in the axial direction. In addition, although the example which uses four spacers 12A-12D which support the shaft 11 is shown here, the number and arrangement (intervals) of the spacers can be appropriately changed.

  The imaging unit 10 is provided so that a subject (not shown) located in front can be imaged at a predetermined viewing angle. As shown in FIG. 6, the imaging unit 10 is arranged behind the objective lens system 21 where the light from the subject enters through the tip cover 6, and the light from the objective lens system 21 is on the front side. A solid-state imaging device 22 that forms an image on the light-receiving surface of the solid-state imaging device, and a drive board 23 that is attached to the rear portion of the solid-state imaging device 22 and transmits / receives various signals to / from the solid-state imaging device 22 and receives power. ing. Although not shown in detail, the objective lens system 21 can be constituted by a plurality of optical lenses.

  The solid-state imaging device 22 is fixed to the front end of the shaft 11 through the drive substrate 23 in the front end cover 6. As the solid-state imaging device 22, a known image sensor made of a relatively small (for example, 1 mm × 1 mm) CMOS (Complementary Metal Oxide Semiconductor) or the like can be used. Note that the setting position of the solid-state imaging element 22 may be at least the front end side of the shaft 11 as long as the imaging is not inhibited.

  The drive board 23 is provided with a voltage conversion circuit of a power source for driving the solid-state imaging device 22, a clock generation circuit, and the like. Although not shown, a cable for transmitting and receiving captured image data, drive power, and the like is disposed between the drive board 23 and the main body 2.

  7 is a perspective view showing the internal structure of the main body 2 of the endoscope 1 with a part omitted, and FIG. 8 is a partially transparent perspective view of the internal structure of the main body 2 in the endoscope 1. 8 is a bottom view of the internal structure shown in FIG. 8, and FIG. 10 is a perspective view of the periphery of the light receiving sensor 54 in the main body 2 (A) on the back side of the substrate and (B) on the front side of the substrate. Hereinafter, the internal structure of the main body 2 will be described with reference to FIGS. 7 to 10 and FIG. For convenience of explanation, the main body 2 also omits the illustration of cables and the like for transmitting and receiving captured image data and driving power.

  As shown in FIG. 5, the housing of the main body 2 includes a substantially cup-shaped cover member 31 and a substantially flat base member 32 fixed to the front side of the cover member 31 with a screw. The opening on the front side of the cover member 31 is closed by the base member 32 to define an internal space. A rear end portion of the protective tube 4 is fitted into a cylindrical fixing portion 33 projecting forward at the front center portion of the base member 32.

  The rear end side of the shaft 11 is inserted into the main body 2 through a through hole 32 a formed at the base end of the fixing portion 33. A shaft pressing member 40 is disposed in the vicinity of the rear portion of the support portion of the fourth spacer 12 </ b> D in the shaft 11. As shown in FIG. 7, the shaft 11 is formed in a support recess 40 a provided on the upper portion of the shaft pressing member 40. It is in a clamped state. A piezo actuator 41 that applies a driving force to the shaft 11 is connected to the lower portion of the shaft pressing member 40.

  The piezo actuator 41 is in contact with the shaft 11 through the shaft pressing member 40 from below, and a driving force is applied to the shaft 11 by the vertical displacement of the piezo actuator 41 due to the reverse piezoelectric effect. The lower part of the piezo actuator 41 is supported by a support member 42, and this support member 42 is fixed to the base member 32 with screws.

  Further, a lower end portion of a compression spring (biasing member) 43 is connected to the upper portion of the shaft pressing member 40. The compression spring 43 is fitted on the shaft pressing member 40 and is in contact with the shaft 11 from above. As a result, the compression spring 43 applies a preload (initial load) to the piezo actuator 41 and expands and contracts in accordance with the vertical displacement when the piezo actuator 41 operates. The upper end portion of the compression spring 43 is connected to a convex portion 45 (see FIG. 5) on the lower surface side of the upper wall 44b in the bracket 44 in which the front wall 44a is fixed to the base member 32 with screws.

  The rear end portion of the shaft 11 is bent upward at a right angle to form an L shape, and the end thereof is supported by a bearing 51 attached to the upper wall 44 b of the bracket 44. The insertion hole 51a of the bearing 51 into which the end of the shaft 11 is inserted is formed as a long hole extending in the front-rear direction, as shown in FIG.

  Further, as shown in FIG. 5, a sensor attachment member 52 is fixed further rearward of the support portion of the shaft pressing member 40 in the shaft 11. As shown in FIG. 10, a light receiving sensor 54 made of a photodiode is attached to the sensor attachment member 52 via a sensor substrate 53. As shown in FIG. 10 (A), the sensor mounting member 52 includes a locking claw 56, a stepped portion 57 disposed so as to face the locking claw 56, and a rear end of the shaft 11 that is L-shaped by the locking hole 58. Since it is attached to the part, it is stably fixed to the shaft 11.

  Further, as shown in FIG. 8, an LED (Light Emitting Diode) 55 is disposed on the light receiving surface side (right side) of the light receiving sensor 54, and this LED 55 emits light toward the light receiving sensor 54 facing the LED 55. . Thereby, based on increase / decrease in the light from the LED 55 detected by the light receiving sensor 54, it is possible to detect the displacement of the shaft 11 (and hence the displacement of the solid-state imaging device 22 at the tip of the shaft 11 described later). As shown in FIG. 9, the LED 55 is fixed to the right wall 44 c of the bracket 44 together with the LED substrate 59.

  FIG. 11 is an operation explanatory diagram during imaging of the endoscope 1 according to the first embodiment, FIG. 12 is an operation explanatory diagram of the endoscope 1 along the XII-XII line section in FIG. 11, and FIG. It is a schematic diagram which shows the mode of the displacement of an image pick-up element at the time of imaging of the endoscope.

  In the endoscope 1, as shown by a solid line in FIG. 11, the shaft 11 is bent in advance by the urging force of the compression spring 43. At this time, in the shaft 11, the support portion by the first spacer 12 </ b> A to the fourth spacer 12 </ b> D is held on the central axis C of the shaft 11 before bending, and the portions between the spacers are vertically curved. Become. Thereby, the play between the first spacer 12A to the fourth spacer 12D and the shaft 11 is suppressed, and the shaft 11 can be stably vibrated or displaced with the first spacer 12A to the fourth spacer 12D as a fulcrum.

  In the endoscope 1, when imaging is started after the power is turned on, a driving voltage is applied to the piezo actuator 41 so that a driving force is applied from the piezo actuator 41 to the shaft 11. At this time, as indicated by an arrow A in FIGS. 11 and 12, the upper end of the piezo actuator 41 is displaced in the x-axis direction (vertical direction) with a predetermined stroke (several μm). As a result, as shown in FIG. 11, the shaft 11 is in a resonance state, and the shaft 11 undergoes a lateral vibration having a portion supported by the first spacer 12 </ b> A to the fourth spacer 12 </ b> D as a node. As a result, in the solid-state imaging device 22 at the tip of the shaft 11, as indicated by an arrow B in FIG. 13, the pixels P (for example, a pixel pitch of 2 μm) are linear within a certain range (for example, the size of several pixels pitch). Can be displaced. Strictly speaking, the displacement of the solid-state imaging device 22 can also occur in the direction of the central axis C, but it is negligible and defocusing does not become a problem.

  Here, the displacement amount of the solid-state imaging device 22 can be estimated from the detection result of the light receiving sensor 54. For example, the amount of displacement can be estimated with high accuracy by investigating the relationship between the amount of light detected by the light receiving sensor 54 and the displacement of the solid-state imaging device 22 in advance.

  As described above, in the endoscope 1 according to the first embodiment, the driving force is applied from the piezo actuator 41 arranged outside the protective tube 4 to vibrate the shaft 11, so that the endoscope 11 is attached to the distal end side of the shaft 11. The solid-state image sensor 22 can be displaced (that is, the light image formed on the light receiving surface of the solid-state image sensor 22 and the solid-state image sensor 22 can be relatively slightly displaced). While realizing a reduction in diameter, it is possible to generate an image having a resolution higher than the original resolution of the image sensor from a plurality of original images acquired by pixel shifting. The obtained imaging data is processed by an image processing apparatus (for example, a general-purpose computer) connected to the endoscope 1 and displayed on a liquid crystal monitor or the like.

  Here, as shown in FIG. 2 described above, the first spacer 12A to the fourth spacer 12D are sequentially arranged behind the mounting position of the imaging unit 10, and the imaging unit 10, the first spacer 12A, and the like. The distance between the first spacer 12A and the fourth spacer 12D is L2. Here, the interval L1 between the imaging unit 10 and the first spacer 12A is set to be smaller than the pitch L2 of the spacers 12A to 12D, but the vibration of the shaft 11 can be changed by changing the ratio between L1 and L2. The amount of displacement of the solid-state image pickup device 22 can be adjusted to a desired size.

  The piezo actuator 41 can be disposed so as to apply a driving force to a portion corresponding to the antinode of vibration of the shaft 11 (between the spacers), but the contact position between the third spacer 12C and the piezo actuator 41 ( It is also possible to adjust the amount of displacement of the solid-state imaging device 22 due to the vibration of the shaft 11 to a desired size by changing the size of the distance L3 (refer to FIG. 11) from the driving force application site. The piezo actuator 41 is capable of generating a relatively large driving force due to its nature, but it is relatively difficult to increase the amount of displacement thereof, so the interval L3 is reduced (in the vicinity of the fourth spacer 12D). To generate a bending moment.

<Modification of First Embodiment>
FIG. 14 is an explanatory diagram of an operation at the time of imaging of the endoscope 1 according to the modification of the first embodiment, and corresponds to FIG. 12 described above. Here, the same code | symbol is attached | subjected about the component similar to 1st Embodiment. Further, this modification example is the same as that of the above-described first embodiment except for matters specifically mentioned below.

  As shown in FIG. 14, in the modification, in the case of the first embodiment, the piezo actuator 41 and the compression spring 43 are arranged so as to be displaceable in the y-axis direction (left-right direction) orthogonal to the x-axis direction. Is different. Here, when a driving voltage is applied to the piezo actuator 41, a driving force acts in the direction of twisting the shaft 11 with the first spacer 12A to the fourth spacer 12D as fulcrums. As a result, the shaft 11 rotates within a predetermined range around the central axis C with the first spacer 12A to the fourth spacer 12D as fulcrums as indicated by an arrow D in FIG. As a result, the solid-state imaging device 22 at the tip of the shaft 11 can be displaced so as to move on the arc within a predetermined range (for example, a size of several pixels pitch).

Second Embodiment
FIG. 15 is an operation explanatory diagram at the time of imaging of the endoscope 1 according to the second embodiment, and corresponds to FIG. 11 described above. Here, the same code | symbol is attached | subjected about the component similar to 1st Embodiment. Moreover, in 2nd Embodiment, it is the same as that of the above-mentioned 1st Embodiment except the matter mentioned especially below.

  As shown in FIG. 15, in the second embodiment, a drive arm 61 extending in a direction orthogonal to the central axis C is provided at a portion to which the drive force of the shaft 11 is applied. The compression spring 43 and the piezo actuator 41 are both arranged so as to be displaceable in a direction parallel to the central axis C direction (left-right direction), and are in contact with the drive arm 61 from the front and rear, respectively. Accordingly, a driving force is applied from the piezoelectric actuator 41 to the shaft 11 via the driving arm 61 due to the displacement of the front end of the piezoelectric actuator 41 in the direction of the central axis C (front-rear direction). As in the case of the first embodiment, the shaft 11 is bent in advance by being biased by a biasing member such as a compression spring (not shown here).

  Here, when the front end of the piezo actuator 41 is displaced forward, the shaft 11 is displaced so as to increase its bending amount as indicated by a broken line in FIG. Thereby, the solid-state imaging device 22 at the tip of the shaft 11 can be linearly displaced in the x-axis direction. Therefore, by repeatedly displacing the front end of the piezo actuator 41 in the front-rear direction, the solid-state imaging device 22 can be linearly displaced within a certain range as in the case of the first embodiment.

  Thus, in the endoscope 1 according to the second embodiment, the driving force is applied from the piezo actuator 41 arranged outside the protective tube 4 to vibrate the shaft 11, so that the endoscope 11 is attached to the distal end side of the shaft 11. Since the solid-state imaging element 22 can be displaced, it is possible to obtain a high-resolution image by performing super-resolution processing on the captured image while reducing the diameter of the insertion portion 3.

<Modification of Second Embodiment>
FIG. 16 is an operation explanatory diagram at the time of imaging of the endoscope 1 according to the modification of the second embodiment. FIG. 16 shows the vicinity of the front end portion of the shaft 11 having a different configuration from that of the second embodiment. This modification is the same as in the case of the second embodiment except for matters specifically mentioned below.

  As shown in FIG. 16A, the front end of the shaft 11 is connected to the center of the rear portion of the drive substrate 23 that supports the solid-state imaging device 22 via the first rotation shaft 71. In addition, the front end of a rod 73 extending in parallel with the front end portion of the shaft 11 is connected to a second rotation shaft 72 provided below the first rotation shaft 71 at the rear portion of the drive substrate 23. The rod 73 has substantially the same length as the distance between the front end of the shaft 11 and the support portion of the first spacer 12A, and the rear end of the rod 73 is disposed below the first spacer 12A. The third rotation shaft 74 is connected. The third rotation shaft 74 is supported by the protective tube 4 or the tip cover 6 (see FIG. 6). An egg-shaped damping gel 75 is sandwiched between the front end of the shaft 11 and the rod 73.

  With such a configuration, a link mechanism is formed by the front end portion of the shaft 11, the rod 73, the first spacer 12 </ b> A and the first to third rotation shafts, and when a driving force is applied to the shaft 11, As shown in FIG. 16B, the solid-state imaging device 22 is displaced in the x-axis direction while maintaining the posture. That is, in the second embodiment described above, the angle with respect to the central axis C slightly changes with the displacement of the solid-state image pickup device 22, but such a link mechanism prevents the angle change of the solid-state image pickup device 22 and makes it more stable. In addition, highly accurate imaging can be realized. In addition, the damping gel 75 between the front end portion of the shaft 11 and the rod 73 can prevent resonance with respect to external vibration input.

<Third Embodiment>
FIG. 17 is an operation explanatory diagram during imaging of the endoscope 1 according to the third embodiment, FIG. 18 is an operation explanatory diagram of the endoscope 1 along the XVIII-XVIII cross section in FIG. 17, and FIG. It is a schematic diagram which shows the mode of the displacement of an image pick-up element at the time of imaging of the endoscope 1 which concerns on 3rd Embodiment. Here, the same code | symbol is attached | subjected about the component similar to 1st Embodiment. Further, the third embodiment is the same as the case of the first embodiment described above except for the matters specifically mentioned below.

  As shown in FIGS. 17 and 18, in the third embodiment, the piezoelectric actuators 41 a and 41 b and the compression springs 43 a and 43 b that make a pair intersect the direction of the central axis C (here, orthogonal), and The second embodiment is different from the first embodiment in that it is displaceable in the p-axis direction and the q-axis direction orthogonal to each other. Here, the piezo actuators 41a and 41b and the compression springs 43a and 43b are arranged between the fourth spacer 12D and the fifth spacer 12E. The fifth spacer 12E has a gimbal mechanism similarly to the first spacer 12A described above.

  When a drive voltage is applied to the piezo actuators 41a and 41b, the solid-state image pickup device 22 can be changed in various curves (circle, ellipse, etc.) like a Lissajous figure or on a straight line depending on the setting of the amount of displacement, frequency and phase. Can be displaced. For example, by shifting the phases of the piezoelectric actuators 41a and 41b by 90 ° and sine-wave vibration with the same displacement amount (amplitude), the shaft 11 is moved from the first spacer 12A to the first spacer as shown by the arrow H in FIG. The four spacers 12D can be rotated within a predetermined range around the central axis C with the fulcrum as a fulcrum. As a result, as indicated by an arrow I in FIG. 19, the pixel P can be moved on a circle having a certain diameter (for example, a size of several pixels pitch).

Although the present invention has been described based on specific embodiments, these embodiments are merely examples, and the present invention is not limited to these embodiments. For example,
Various changes can be made to the material and shape (diameter, length) of the shaft that transmits the driving force of the actuator. The shaft may be any shaft that can transmit at least the bending moment generated by the piezoelectric actuator on the rear end side to the front end side. Further, the number and arrangement of the piezoelectric actuators and compression springs can be variously changed, and a plurality of operation methods in the above-described embodiments can be used in combination. It should be noted that not all the constituent elements of the endoscope according to the present invention shown in the above embodiment are necessarily essential, and can be appropriately selected as long as they do not depart from the scope of the present invention.

  The endoscope according to the present invention can obtain a high-resolution image by performing super-resolution processing on a captured image while having a configuration in which the diameter of the insertion portion can be reduced. It is useful as an endoscope for obtaining

DESCRIPTION OF SYMBOLS 1 Endoscope 2 Main-body part 3 Insertion part 4 Protective tube 6 Tip cover 10 Imaging unit 11 Shaft (drive force transmission shaft)
12A to 12E First to fifth spacers 21 Objective lens system 22 Solid-state imaging device 23 Drive substrate 31 Cover member 32 Base member 41 Piezo actuator 41
43 Compression spring (biasing member)
54 Light receiving sensor 55 LED

Claims (5)

A protective tube that forms an insertion portion to be inserted into the subject;
A driving force transmission shaft that is inserted through the protective tube and supported by a plurality of spacers arranged in the axial direction at a predetermined pitch in the protective tube;
An image sensor attached to the tip side of the driving force transmission shaft;
An actuator that generates lateral vibration with the support portions of the plurality of spacers as nodes in the driving force transmission shaft by applying a driving force to the base end side of the driving force transmission shaft outside the protective tube. And an endoscope.   The endoscope according to claim 1, further comprising a biasing member that biases the driving force transmission shaft in an initial state between the spacers by biasing the driving force transmission shaft.   The endoscope according to claim 1, wherein the actuator includes two actuators that apply the driving force in two directions intersecting each other.   The position detection sensor further fixed to the base end side rather than the drive force provision site | part of the said actuator in the said drive force transmission shaft, The position detection sensor which detects the position of the said drive force transmission shaft is further provided. Item 5. The endoscope according to any one of Items 3. A protective tube that forms an insertion portion to be inserted into the subject;
A driving force transmission shaft supported by a plurality of spacers arranged in the axial direction at a predetermined pitch in the protective tube;
An image sensor attached to the tip side of the driving force transmission shaft;
An urging member that bends the driving force transmission shaft in an initial state between the spacers by urging the driving force transmission shaft;
By applying a driving force to the base end side of the driving force transmission shaft outside the protective tube, the driving force transmission shaft is periodically rotated about the support portions of the plurality of spacers. An endoscope comprising an actuator.

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