JP2016147021A - Scanning endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scanning endoscope capable of shortening the length of a hard section at a tip of an insertion section without lowering capability for swinging a light guide part.SOLUTION: The scanning endoscope includes: piezoelectric elements 61, 63, 65, and 67 that are provided lateral to a fiber tip-side area 12a of an illumination fiber that guides illumination light for illuminating a subject to exit it from an outgoing end, and that extend/contract for swinging the fiber tip-side area 12a according to an electric field; and piezoelectric elements 62, 64, 66, and 68 that are superposedly provided on an upper layer of the piezoelectric elements 61, 63, 65, and 67 and extend/contract for swinging the fiber tip-side area 12a according to the electric field.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a scanning endoscope that scans a subject with illumination light emitted from a light source unit to acquire an image.

  In endoscopes in the medical field, various techniques have been proposed for reducing the diameter of an insertion portion that is inserted into a body cavity of a subject in order to reduce the burden on the subject. As one of such techniques, a scanning endoscope that does not have a solid-state imaging device in an insertion portion is known.

  Specifically, for example, the scanning endoscope operates an actuator unit attached to an illumination fiber (light guide unit) that guides illumination light emitted from a light source unit, and connects the illumination fiber to a predetermined level. By oscillating with the scanning pattern, the subject within the scanning range corresponding to the scanning pattern is scanned. As an actuator unit used in this type of scanning endoscope, for example, a configuration in which an actuator made of a piezoelectric element is arranged on each side surface of a prismatic ferrule having an illumination fiber fixedly arranged at the center is known. (For example, refer to Patent Document 1).

JP 2014-94158 A

  By the way, generally an actuator part etc. need to be arrange | positioned in the hard frame which comprises the front-end | tip hard part of an insertion part. Therefore, in order to shorten the length of the hard tip portion and improve the insertability of the insertion portion, it is desirable to shorten the length in the insertion axis direction of each actuator constituting the actuator portion.

  However, when the length of each actuator is shortened, the amount of force for swinging the light guide portion is reduced. On the other hand, for example, it is conceivable to increase the output of a drive voltage or the like applied to each actuator as a drive signal. In particular, in a medical scanning endoscope inserted into a body cavity, the actuator is driven. There is a limit to increasing the signal output.

  The present invention has been made in view of the above circumstances, and provides a scanning endoscope capable of shortening the length of the hard portion at the distal end of the insertion portion without reducing the amount of force for swinging the light guide portion. The purpose is to provide.

  A scanning endoscope according to an aspect of the present invention is provided with a light guide unit that guides illumination light for illuminating a subject and emits the light from an output end, and is provided on a side of the light guide unit. A first actuator that expands and contracts to swing the tip of the light guide unit in response to the applied electric field, and is disposed to overlap the first actuator, and the light guide unit in accordance with the applied electric field. And a second actuator that expands and contracts in order to swing the tip.

  According to the scanning endoscope of the present invention, the length of the hard portion at the distal end of the insertion portion can be shortened without reducing the force for swinging the light guide portion.

The figure which shows the structure of the principal part of an optical scanning type observation system concerning one Embodiment of this invention. Same as above, sectional view of the main part of the hard tip The perspective view which shows the principal part of the actuator part with which the fiber for illumination was mounted | worn with the same as the above. As above, an explanatory view showing the polarization direction of each piezoelectric element constituting the actuator unit Same as above, end view showing the actuator section from the tip side Same as above, sectional view taken along line VI-IV in FIG. Same as above, operation explanation of actuator section The figure which shows an example of the signal waveform of the drive signal supplied to an actuator part same as the above. The figure which shows an example of the spiral scanning path | route from the center point A to the outermost point B same as the above. The figure which shows an example of the spiral scanning path | route from the outermost point B to the center point A same as the above. Explanatory drawing which shows the polarization direction of each piezoelectric element which comprises an actuator part according to a modification. Same as above, end view showing the actuator section from the tip side Same as above, sectional view taken along line XIII-XIII in FIG. Same as above, operation explanation of actuator section

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to an embodiment of the present invention, FIG. 1 is a diagram showing the configuration of the main part of the optical scanning observation system, FIG. 2 is a cross-sectional view of the main part of the hard tip, and FIG. FIG. 4 is an explanatory view showing the polarization direction of each piezoelectric element constituting the actuator part, FIG. 5 is an end view showing the actuator part from the tip side, and FIG. FIG. 7 is an explanatory diagram of the operation of the actuator unit, FIG. 8 is a diagram showing an example of a signal waveform of a drive signal supplied to the actuator unit, and FIG. 9 is an outermost point B from the center point A FIG. 10 is a diagram showing an example of a spiral scanning path extending from the outermost point B to the center point A. FIG.

  An optical scanning observation system 1 shown in FIG. 1 is connected to, for example, a scanning endoscope 2 inserted into a body cavity of a subject, a main body device 3 to which the endoscope 2 can be connected, and the main body device 3. And the monitor 4 to be configured.

  The scanning endoscope 2 has an elongated insertion portion 11 that can be inserted into a body cavity of a subject.

  A connector portion 41 for detachably connecting the endoscope 2 to the connector receiving portion 42 of the main body device 3 is provided on the proximal end side of the insertion portion 11. On the other hand, a hard distal end hard portion 11 a is provided at the distal end of the insertion portion 11.

  The distal end hard part 11a receives the light emission side end of the illumination fiber 12 having a function as a light guide part for guiding the illumination light supplied from the main body device 3, and the return light from the subject. A light incident side end of the light receiving fiber 13 guided to the main body device 3, a condensing optical system 14 configured to condense and emit the illumination light emitted from the illumination fiber 12, and the main body device 3 is provided with an actuator section 15 that can oscillate the light emission side end of the illumination fiber 12 based on a drive signal output from the illumination fiber 12.

  The main unit 3 includes a light source unit 21, a driver unit 22, a detection unit 23, a memory 24, and a controller 25.

  The light source unit 21 includes a light source 31a, a light source 31b, a light source 31c, and a multiplexer 32.

  The light source 31a includes, for example, a laser light source and the like, and is configured to emit red wavelength band light (hereinafter also referred to as R light) to the multiplexer 32 when turned on under the control of the controller 25. Yes.

  The light source 31b includes a laser light source, for example, and is configured to emit light in a green wavelength band (hereinafter also referred to as G) to the multiplexer 32 when turned on under the control of the controller 25. .

  The light source 31c includes, for example, a laser light source, and is configured to emit light in a blue wavelength band (hereinafter also referred to as B light) to the multiplexer 32 when turned on under the control of the controller 25. Yes.

  The multiplexer 32 multiplexes the R light emitted from the light source 31a, the G light emitted from the light source 31b, and the B light emitted from the light source 31c onto the light incident surface of the illumination fiber 12. It is configured to supply.

  The driver unit 22 includes a signal generator 33, D / A converters 34a and 34b, and an amplifier 35.

  Based on the control of the controller 25, the signal generator 33 generates a drive signal for swinging the end including the light emitting surface of the illumination fiber 12 and outputs the drive signal to the D / A converters 34a and 34b. It is configured.

  The D / A converters 34 a and 34 b are configured to convert the digital drive signal output from the signal generator 33 into an analog drive signal and output the analog drive signal to the amplifier 35.

  The amplifier 35 is configured to amplify the drive signals output from the D / A converters 34 a and 34 b and output the amplified drive signals to the actuator unit 15.

  On the other hand, the detection unit 23 includes a duplexer 36, detectors 37a, 37b, and 37c, and A / D converters 38a, 38b, and 38c.

  The demultiplexer 36 includes a dichroic mirror and the like, and separates the return light emitted from the light emitting surface of the light receiving fiber 13 into light for each of R (red), G (green), and B (blue) color components. And it is comprised so that it may radiate | emit to the detectors 37a, 37b, and 37c.

  The detector 37a detects the intensity of the R light output from the duplexer 36, generates an analog R signal corresponding to the detected intensity of the R light, and outputs the analog R signal to the A / D converter 38a. It is configured.

  The detector 37b detects the intensity of the G light output from the duplexer 36, generates an analog G signal corresponding to the detected intensity of the G light, and outputs the analog G signal to the A / D converter 38b. It is configured.

  The detector 37c detects the intensity of the B light output from the duplexer 36, generates an analog B signal according to the detected intensity of the B light, and outputs the analog B signal to the A / D converter 38c. It is configured.

  The A / D converter 38 a is configured to convert the analog R signal output from the detector 37 a into a digital R signal and output it to the controller 25.

  The A / D converter 38b is configured to convert the analog G signal output from the detector 37b into a digital G signal and output the digital G signal to the controller 25.

  The A / D converter 38 c is configured to convert the analog B signal output from the detector 37 c into a digital B signal and output it to the controller 25.

  The memory 24 stores in advance a control program for controlling the main device 3.

  The controller 25 includes a CPU and the like, reads a control program stored in the memory 24, and controls the light source unit 21 and the driver unit 22 based on the read control program, thereby controlling the light source control unit 25a and the scanning. Each function as the control unit 25b and the image generation unit 25c is realized. That is, the controller 25 (light source control unit 25a) is configured to perform control on the light source unit 21 based on the control information read from the memory 24, for example, to cause the light sources 31a to 31c to emit light simultaneously. Further, the controller 25 (scanning control unit 25b) performs control on the driver unit 22 to generate a drive signal having a signal waveform as shown in FIG. 8, for example, based on the control information read from the memory 24. It is configured as follows. For example, the controller 25 (image generation unit 25c) detects the most recent scanning path based on the image waveform of the drive signal generated according to the control of the scanning control unit 25b, and illumination on the detected scanning path. A raster scan format pixel position corresponding to the light irradiation position is specified, and a luminance value indicated by a digital signal output from the detection unit 23 is mapped to the specified pixel position, thereby generating an observation image for one frame. The generated one-frame sentence observation image is sequentially output to the monitor 4.

  Next, a detailed configuration of the distal end hard portion 11a including the actuator portion 15 will be described with reference to FIG.

  As shown in FIG. 2, the distal end hard portion 11 a has a hard lens frame pipe 50. A flexible sheath 51 is provided on the outer periphery of the lens frame pipe 50, and the distal ends of the plurality of light receiving fibers 13 are arranged in an annular shape between the lens frame pipe 50 and the sheath 51. It is held at.

  On the other hand, on the front end side of the lens frame pipe 50, a condensing unit is provided with a lens 14a into which the illumination light guided from the illumination fiber 12 is incident and a lens 14b that emits the illumination light that has passed through the lens 14a. The optical system 14 is held.

  Further, on the proximal end side with respect to the condensing optical system 14, the light emission side of the illumination fiber 12 is disposed inside the lens frame pipe 50, and further, the light emission side of the illumination fiber 12 is swung. The actuator portion 15 is provided.

  More specifically, in this embodiment, the region on the distal end side (fiber distal end region 12a) including the light emission side of the illumination fiber 12 disposed in the distal rigid portion 11a is the region on the proximal end side. It is configured by an optical fiber separate from the (fiber proximal end region 12b). And these fiber front end side area | region 12a and fiber base end side area | region 12b are optically connected through the ferrules 53 and 54 as a connection member. That is, the fiber front end side region 12a and the fiber base end side region 12b are optically connected by holding the ferrules 53 and 54 fixed to the respective connection parts in the ferrule folder 55 having a sleeve shape. ing.

  Further, the ferrule folder 55 is fitted to the proximal end side of the lens frame pipe 50, whereby the fiber distal end side region 12 a is in a state where the end portion on the light emitting side faces the lens 14 a of the condensing optical system 14. Are disposed in the lens frame pipe 50.

  Here, for example, as shown in FIGS. 3 and 5, in this embodiment, the ferrule 53 fixed to the fiber tip side region 12 a is formed in a quadrangular prism shape by a conductive material. That is, the ferrule 53 has a pair of side surfaces 53a and 53b that face each other in one direction perpendicular to the central axis O (hereinafter referred to as the X-axis direction), and is perpendicular to the central axis O and the X axis. And a pair of side surfaces 53c and 53d facing each other in the direction (hereinafter referred to as the Y-axis direction). In other words, the ferrule 53 includes a pair of side surfaces 53a and 53b perpendicular to the X axis, which are lateral to the illumination fiber 12 (fiber tip side region 12a), and the illumination fiber 12 (fiber tip side region 12a). It has a pair of side surfaces 53c and 53d perpendicular to the Y axis which is the side.

  The front end side of the ferrule 53 protrudes from the ferrule folder 55, and a plurality of actuators for configuring the actuator unit 15 are provided on the side surfaces 53 a to 53 d on the protruded front end side.

  That is, for example, as shown in FIGS. 2 to 6, the ferrule 53 has a piezoelectric element 61 as a first actuator attached to one side surface 53 a perpendicular to the X axis, and the piezoelectric element 61. On the upper layer, a piezoelectric element 62 as a second actuator is superposed and stuck. Each of the piezoelectric elements 61 and 62 includes an elongated (polarized) elongated piezoelectric layer 61a and 62a, and a first electrode layer formed on the positive electrode side in the polarization direction of the piezoelectric layers 61a and 62a. 61b, 62b and second electrode layers 61c, 62c formed on the negative electrode side in the polarization direction of the piezoelectric layers 61a, 62a. Among these, the piezoelectric element 61 is held by the ferrule 53 and is electrically connected to the ferrule 53 when the second electrode layer 61c is attached to the side surface 53a. In addition, the piezoelectric element 62 is superposed on the piezoelectric element 61 by the first electrode layer 62 b being attached to the first electrode layer 61 b of the piezoelectric element 61, and the first of the piezoelectric element 61 is also retained. The electrode layer 61b is electrically connected. For example, on the base end side of the piezoelectric elements 61 and 62, a single signal line 75a for transmitting a drive signal from the D / A converter 34a is electrically connected to the first electrode layers 61b and 62b. It is connected. On the other hand, an insulating portion 76 that insulates at least a part of the first electrode layers 61b and 62b is provided on the tip surfaces of the piezoelectric elements 61 and 62, and is made of a silver paste or the like formed across the insulating portion 76. The second electrode layer 62 c of the piezoelectric element 62 is electrically connected to the ferrule 53 through the conductive portion 77. With such mounting on the ferrule 53, an electric field in the same direction is applied to the piezoelectric elements 61 and 62 with respect to the polarization directions of the piezoelectric elements 61 and 62 by the drive signal applied from the signal line 75a. . That is, when a forward electric field is applied to the piezoelectric element 61 with respect to the polarization direction of the piezoelectric element 61 by the drive signal from the signal line 75 a, the piezoelectric element 62 is similarly configured of the piezoelectric element 62. A forward electric field is applied to the polarization direction. On the other hand, when an electric field in the direction opposite to the polarization direction of the piezoelectric element 62 is applied to the piezoelectric element 61 by the drive signal from the signal line 75a, the piezoelectric element 62 is similarly configured of the piezoelectric element 62. An electric field in the opposite direction to the polarization direction is applied. Thereby, the piezoelectric element 61 and the piezoelectric element 62 perform the same expansion / contraction operation according to the drive signal applied from the signal line 75a.

  In addition, a piezoelectric element 63 as a first actuator is attached to the ferrule 53 on the other side surface 53b perpendicular to the X-axis, and a piezoelectric element as a second actuator is formed above the piezoelectric element 63. 64 is superimposed and pasted. Each of the piezoelectric elements 63 and 64 includes an elongated (polarized) elongated piezoelectric layer 63a and 64a, and a first electrode layer formed on the positive electrode side in the polarization direction of the piezoelectric layers 63a and 64a. 63b, 64b, and second electrode layers 63c, 64c formed on the negative electrode side in the polarization direction of the piezoelectric layers 63a, 64a. Among these, the piezoelectric element 63 is held by the ferrule 53 and is electrically connected to the ferrule 53 by attaching the first electrode layer 63b to the side surface 53b. In addition, the piezoelectric element 64 is held in a superimposed manner on the piezoelectric element 63 by attaching the second electrode layer 64 c to the second electrode layer 63 c of the piezoelectric element 63, and the negative electrode of the piezoelectric element 63. It is electrically connected to the layer 63c. For example, on the base end side of the piezoelectric elements 63 and 64, a single signal line 75a for transmitting a drive signal from the D / A converter 34a is electrically connected to the second electrode layers 63c and 64c. It is connected. On the other hand, an insulating portion 76 that insulates at least a part of the second electrode layers 63c and 64c is provided on the front end surfaces of the piezoelectric elements 63 and 64, and is made of a silver paste or the like formed across the insulating portion 76. The first electrode layer 64 b of the piezoelectric element 64 is electrically connected to the ferrule 53 through the conductive portion 77. With such mounting on the ferrule 53, an electric field in the same direction is applied to the piezoelectric elements 63 and 64 with respect to each polarization direction of the piezoelectric elements 63 and 64 by a drive signal applied from the signal line. That is, when a forward electric field with respect to the polarization direction of the piezoelectric element 63 is applied to the piezoelectric element 63 by the drive signal from the signal line 75a, the piezoelectric element 64 is similarly configured to have the piezoelectric element 64. A forward electric field is applied to the polarization direction. On the other hand, when an electric field in the direction opposite to the polarization direction of the piezoelectric element 63 is applied to the piezoelectric element 63 by the drive signal from the signal line 75a, the piezoelectric element 64 is similarly configured of the piezoelectric element 64. An electric field in the opposite direction to the polarization direction is applied. Thereby, the piezoelectric element 63 and the piezoelectric element 64 perform the same expansion / contraction operation according to the drive signal applied from the signal line 75a. However, in the piezoelectric elements 63 and 64, since the second electrode layers 63c and 64c are connected to the signal line 75a, the piezoelectric elements 61 and 62 in which the first electrode layers 61b and 62b are connected to the signal line 75a. Reverse expansion and contraction is performed.

  In addition, a piezoelectric element 65 as a first actuator is attached to the ferrule 53 on one side surface 53c perpendicular to the Y-axis, and a piezoelectric element as a second actuator is formed above the piezoelectric element 65. 66 is superimposed and pasted. Each of the piezoelectric elements 65 and 66 includes an elongated (polarized) elongated piezoelectric layer 65a and 66a, and a first electrode layer formed on the positive electrode side in the polarization direction of the piezoelectric layers 65a and 66a. 65b, 66b and second electrode layers 65c, 66c formed on the negative electrode side in the polarization direction of the piezoelectric layers 65a, 66a. The piezoelectric elements 65 and 66 are held on the side surface 53c with the same configuration as the piezoelectric elements 61 and 62 provided on the one side surface 53a perpendicular to the X axis. However, instead of the signal line 75a, a single signal line 75b (see FIG. 1) for transmitting a drive signal from the D / A converter 34b is electrically connected to each of the first electrode layers 65b and 66b. Has been.

  In addition, a piezoelectric element 67 as a first actuator is attached to the ferrule 53 on the other side surface 53d perpendicular to the Y-axis, and a piezoelectric element as a second actuator is formed above the piezoelectric element 67. 68 is superimposed and pasted. Each of the piezoelectric elements 67 and 68 includes an elongated (polarized) elongated piezoelectric layer 67a and 68a, and a first electrode layer formed on the positive electrode side in the polarization direction of the piezoelectric layers 67a and 68a. 67b, 68b and second electrode layers 67c, 68c formed on the negative electrode side in the polarization direction of the piezoelectric layers 67a, 68a. These piezoelectric elements 67 and 68 are held on the side surface 53d with the same configuration as the piezoelectric elements 63 and 64 provided on the other side surface 53b perpendicular to the X axis. However, instead of the signal line 75a, a single signal line 75b (see FIG. 1) for transmitting a drive signal from the D / A converter 34b is electrically connected to each of the second electrode layers 67c and 68c. Has been.

  Accordingly, for example, as shown in FIG. 4, a plurality (one set) of piezoelectric elements 61, piezoelectric elements 62, and piezoelectric elements 63 are superimposed on the side surfaces 53 a to 53 d of the ferrule 53 in different polarization directions. The piezoelectric element 64, the piezoelectric element 65 and the piezoelectric element 66, and the piezoelectric element 67 and the piezoelectric element 68 are held.

  And in the actuator part 15 comprised in this way, the drive voltage according to the 1st drive signal which comprises a signal waveform as shown by the broken line of FIG. 8, for example is applied to the piezoelectric elements 61-64 of the actuator part 15 At the same time, a driving voltage corresponding to the second driving signal having a signal waveform as shown by a one-dot chain line in FIG. 8 is applied to the piezoelectric elements 65 to 68 of the actuator unit 15. As a result, the piezoelectric elements (piezoelectric element 61 and piezoelectric element 62, piezoelectric element 63 and piezoelectric element 64, piezoelectric element 65 and piezoelectric element 66, and piezoelectric element 67 and piezoelectric element 68) forming each set expand and contract according to each drive signal. Perform the action. For example, when the drive voltage Vt1 is applied to the piezoelectric elements 61 to 64 at a certain timing t, an electric field is generated between the electrode layers by the drive voltage Vt1. In response to this electric field, as shown in FIG. 7, the piezoelectric elements 61 and 62 expand (or contract), and the piezoelectric elements 63 and 64 contract (or expand) and expand and contract. As a result, the illumination fiber 12 (fiber tip side region 12a) is vibrated in the X-axis direction. Further, for example, when a driving voltage Vt2 having a predetermined phase delay from the driving voltage Vt1 is applied to the piezoelectric elements 65 to 68 at a certain timing t, an electric field is generated between the electrode layers by the driving voltage Vt2. Similarly, although not shown, the piezoelectric elements 65 and 66 expand (or contract) with a predetermined phase delay from the piezoelectric elements 61 and 62 according to the electric field, and the piezoelectric elements 67 and 68 The contraction operation (or expansion operation) with a predetermined phase delay from the piezoelectric elements 63 and 64 causes the illumination fiber 12 (fiber tip side region 12a) to be vibrated in the Y-axis direction. The Then, due to these vibrations, the exit end of the illumination fiber 12 (fiber tip side region 12a) is swung in a spiral shape, and the surface of the subject is shown in FIGS. 9 and 10 according to such swinging. Scanning is performed by such a spiral scanning path. FIG. 9 is a diagram illustrating an example of a spiral scanning path from the center point A to the outermost point B. FIG. FIG. 10 is a diagram illustrating an example of a spiral scanning path from the outermost point B to the center point A. FIG.

  According to such an embodiment, a fiber tip side region corresponding to an electric field is formed on the side of the fiber tip side region 12a of the illumination fiber 12 that guides illumination light for illuminating the subject and emits the light from the output end. The piezoelectric elements 61, 63, 65, 67 that expand and contract to swing the 12a are provided, and the fiber distal end side region 12a is swung according to the electric field on the piezoelectric elements 61, 63, 65, 67. For this reason, the length of the hard portion at the distal end of the insertion portion (the distal end is reduced without reducing the amount of force for swinging the fiber distal end side region 12a by providing the piezoelectric elements 62, 64, 66, and 68 that extend and contract in an overlapping manner. The length of the hard portion 11a) can be shortened.

  That is, by adopting a multilayer structure in which a plurality of piezoelectric elements are superposed on the actuator unit 15 and reducing the gap between the electrode layers of each piezoelectric element, each drive signal (drive voltage) can be output without increasing the output. A high electric field can be applied to the piezoelectric element, and the amount of force required to vibrate the fiber tip side region 12a can be increased as compared with the case where a single-phase piezoelectric element having an equivalent volume as a total is used. As a result, the length of the actuator unit 15 in the optical axis O direction can be shortened, and the length of the distal end hard portion 11a can be shortened.

  In this case, even when the piezoelectric elements are multi-layered by polarizing the superimposed piezoelectric elements in different polarization directions, it is possible to cope with each set of piezoelectric elements disposed on each side surface of the ferrule 53. The signal lines 75a and 75b to be shared can be efficiently shared, and the same expansion and contraction operation can be performed for each set of piezoelectric elements.

  The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the technical scope of the present invention. For example, in the above-described embodiment in which a plurality of piezoelectric elements are superimposed and arranged so that the polarization directions are staggered, three or more layers of piezoelectric elements are superimposed on each of the side surfaces 53a to 53d while maintaining the above-described wiring relationship. It is also possible. FIG. 11 shows an example in which piezoelectric elements 81, 82, 83, and 84 are superposed on the upper layers of the piezoelectric elements 62, 64, 66, and 68. In this case, the first-layer piezoelectric element and the second-layer piezoelectric element on the side of the fiber distal end region 12a correspond to the first actuator and the second actuator of the present invention. That is, in this modification, the first-layer piezoelectric element and the second-layer piezoelectric element are stacked in different polarization directions, and expand and contract in the same direction according to the applied drive signal. So that it is electrically connected. The second layer piezoelectric element and the third layer piezoelectric element also correspond to the first actuator and the second actuator of the present invention. In other words, in the present modification, the second-layer piezoelectric element and the third-layer piezoelectric element are stacked with different polarization directions, as described below, and according to the applied drive signal. Are electrically connected to expand and contract in the same direction.

  In such a configuration, for example, as shown in FIGS. 12 and 13, the second electrode layer 81 c formed on the negative electrode side in the polarization direction of the piezoelectric element 81 is formed on the second electrode layer 62 c of the piezoelectric element 62. By being affixed, the piezoelectric element 62 is superimposed and held, and is electrically connected to the second electrode layer 62c of the piezoelectric element 62. On the other hand, an insulating portion 76 that insulates at least a part of the second electrode layers 62c and 81c is provided on the base end surfaces of the piezoelectric elements 62 and 81, and is made of a silver paste or the like formed across the insulating portion 76. The first electrode layers 61 b and 62 b of the piezoelectric elements 61 and 62 are electrically connected to the first electrode layer 81 b of the piezoelectric element 81 through the conductive portion 77.

  Further, the first electrode layer 82 b formed on the positive electrode side in the polarization direction of the piezoelectric element 82 is attached to the first electrode layer 64 b of the piezoelectric element 64 so as to be superimposed on the piezoelectric element 64. In addition, it is electrically connected to the first electrode layer 64b of the piezoelectric element 64. On the other hand, an insulating portion 76 that insulates at least a part of the first electrode layers 63b and 64b is provided on the tip surfaces of the piezoelectric elements 63 and 64, and is made of a silver paste or the like formed across the insulating portion 76. The second electrode layers 63 c and 64 c of the piezoelectric elements 63 and 64 are electrically connected to the second electrode layer 82 c of the piezoelectric element 82 via the conductive portion 77.

  Although detailed description is omitted, for example, for the piezoelectric element 83, the first and second electrode layers 83b and 83c are connected in the same manner as the first and second electrode layers 81b and 81c of the piezoelectric element 81. The piezoelectric element 66 can be stacked on top of the piezoelectric element 66 so that the relationship is established. For the piezoelectric element 84, the first and second electrode layers 84b and 84c are the first and second electrode layers of the piezoelectric element 82. It can be laminated on the upper layer of the piezoelectric element 68 so as to have the same connection relationship as 82b and 82c. With these configurations, for example, as shown in FIG. 14, even when three or more piezoelectric elements are stacked, the same operation as that of the above-described embodiment can be realized.

  Furthermore, although not shown in the figure, for example, if it is assumed that an insulating layer or the like is appropriately interposed between electrode layers overlapping each other, and signal lines and conductive wirings are individually wired for each piezoelectric element as necessary, etc. It is also possible to superimpose a plurality of piezoelectric elements in the polarization direction.

DESCRIPTION OF SYMBOLS 1 ... Optical scanning observation system 2 ... Scanning endoscope 3 ... Main body apparatus 4 ... Monitor 11 ... Insertion part 11a ... Hard tip part 12 ... Illumination fiber 12a ... Fiber front end side area | region 12b ... Fiber base end side area | region 13 ... Light receiving fiber 14 ... Condensing optical system 14a ... Lens 14b ... Lens 15 ... Actuator unit 21 ... Light source unit 22 ... Driver unit 23 ... Detection unit 24 ... Memory 25 ... Controller 50 ... Lens frame pipe 51 ... Sheath 53 ... Ferrule 53a to 53d ... Side 54 ... Ferrule 55 ... Ferrule holder 61 ... Connector portion 61, 63, 65, 67 ... Piezoelectric element (first actuator)
62, 64, 66, 68 ... Piezoelectric element (second actuator / first actuator)
81-84 ... Piezoelectric element (second actuator)
61a, 62a, 63a, 64a, 65a, 66a, 67a, 68a ... Piezoelectric layer 61b, 62b, 63b, 64b, 65b, 66b, 67b, 68b ... First electrode layer (electrode)
61c, 62c, 63c, 64c, 65c, 66c, 67c, 68c ... 2nd electrode layer (electrode)
75a, 75b ... signal line 76 ... insulating part 77 ... conductive part

Claims (6)

A light guide for guiding the illumination light for illuminating the subject and emitting it from the exit end; and
A first actuator provided on a side of the light guide and extending and contracting to swing the tip of the light guide in response to an applied electric field;
A second actuator that is arranged so as to overlap with the first actuator and expands and contracts to swing the tip of the light guide unit according to an applied electric field;
A scanning endoscope characterized by comprising: A ferrule interposed between the light guide and the first actuator;
A common signal line electrically connected to each electrode formed on the overlapping surface of the first actuator and the second actuator;
The scanning endoscope according to claim 1, further comprising:   The scanning endoscope according to claim 2, wherein the first actuator and the second actuator are piezoelectric elements polarized in different polarization directions. A ferrule that is interposed between the light guide section and the first actuator and that is directly connected to an electrode formed on a surface of the first actuator that is not superimposed on the second actuator;
A common signal line electrically connected to each electrode formed on the overlapping surface of the first actuator and the second actuator;
A connection portion for conducting an electrode formed on a surface of the second actuator that is not overlapped with the first actuator, to the ferrule;
The scanning endoscope according to claim 1, further comprising: An insulating portion that insulates at least a part of the end portions of the electrodes formed on the overlapping surfaces of the first actuator and the second actuator;
The connecting portion is a conductive portion for conducting the electrode formed on the surface of the second actuator that is not superimposed on the first actuator, across the insulating portion to the ferrule. The scanning endoscope according to claim 4.   The scanning endoscope according to claim 4, wherein the first actuator and the second actuator are piezoelectric elements polarized in different directions.

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