JP2014145899A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanner capable of accurately vibrating a vibrated part in a desired direction with a simple structure.SOLUTION: An optical scanner two-dimensionally scans an object by radiating light emitted from an optical fiber 11 onto the object while vibrating the exit end part of the optical fiber 11 by a scanning part 21. The optical scanner includes a vibration adjustment part 70 for adjusting vibration characteristics of a vibrated part including the exit end part of the optical fiber 11.

Description

  The present invention relates to an optical scanning device.

  For example, as a medical endoscope or an industrial endoscope, an electronic endoscope using a solid-state imaging device such as a CCD or a CMOS as an imaging unit is known. However, the electronic endoscope has a limit in reducing the diameter of the endoscope distal end because the solid-state imaging device is disposed at the endoscope distal end. Therefore, as an endoscope in which the diameter of the endoscope tip can be made smaller than that of an electronic endoscope, the exit end of the optical fiber that irradiates light to the object to be observed is used at high speed without using a solid-state imaging device. There has been proposed a scanning endoscope that acquires an image by scanning an object to be observed by vibration (see, for example, Patent Document 1).

  The scanning endoscope disclosed in Patent Document 1 includes a permanent magnet attached to an emission end portion of an optical fiber, and four coils arranged on an inner wall of a housing around the permanent magnet. The four coils constitute an X coil in which one of the two opposing coils drives the exit end of the optical fiber in the X-axis direction, and the other two coils orthogonally intersect the exit end of the optical fiber with the X-axis direction. A Y coil driven in the Y-axis direction is configured. The X coil is fed with a current having a frequency corresponding to the resonance frequency of the vibrating end including the exit end of the optical fiber and the permanent magnet. A current having a frequency lower than the resonance frequency is supplied to the Y coil. As a result, the vibrating portion including the emission end of the optical fiber and the permanent magnet vibrates at high speed at the resonance frequency in the X-axis direction and vibrates at low speed in the Y-axis direction, and the object to be observed is raster scanned.

JP 2008-116922 A

  However, in the configuration disclosed in Patent Document 1, when the object to be observed is raster-scanned with a constant amplitude in the X-axis direction and the Y-axis direction, the vibration locus of the object to be observed, that is, the object to be observed is detected. The trajectory of the irradiating light may not be stably orthogonal to the X-axis direction and the Y-axis direction in the image acquisition scanning range, and the image may be distorted. As the cause, it is assumed that the vibrating part is not configured symmetrically in the X-axis direction or the Y-axis direction, the coil is inclined with respect to the optical fiber, or the like. Such a phenomenon occurs not only in raster scanning but also in other scanning such as spiral scanning.

  Accordingly, an object of the present invention made in view of such a point is to provide an optical scanning device capable of accurately vibrating a vibrating portion in a desired direction with a simple configuration.

An optical scanning device according to the present invention that achieves the above object is as follows.
An optical scanning device that two-dimensionally scans the object by irradiating the object with light emitted from the optical fiber while vibrating the exit end of the optical fiber by a scanning unit,
A vibration adjustment unit that adjusts vibration characteristics of a portion to be vibrated including the emission end of the optical fiber;
It is characterized by this.

  The scanning unit includes a permanent magnet that is provided at the exit end of the optical fiber and that forms the vibrated portion together with the exit end, and a plurality of coils that are disposed around the permanent magnet. can do.

  The vibration adjusting unit adjusts the stationary position of the vibration-receiving portion at least about the first axis or the second axis in the direction orthogonal to the two-dimensional scanning plane of the optical fiber, and the vibration characteristics May be adjusted.

  The vibration adjusting unit may adjust the vibration characteristic by adjusting a relative position of at least one of the coils with respect to the permanent magnet at a stationary position of the vibrating part.

  The vibration adjusting unit may have a notch formed in the permanent magnet, and may adjust the vibration characteristic by adjusting a direction of the notch.

  The vibration adjusting unit may adjust the vibration characteristic by adjusting a mass of the portion to be vibrated.

  The vibration adjustment unit may adjust the vibration characteristic by adjusting a mass of the permanent magnet.

  According to the present invention, it is possible to provide an optical scanning device that can vibrate a vibrating part accurately in a desired direction with a simple configuration.

1 is a block diagram illustrating a schematic configuration of an optical scanning endoscope apparatus that is an example of an optical scanning apparatus according to a first embodiment. FIG. FIG. 2 is an overview diagram schematically showing the optical scanning endoscope main body of FIG. 1. It is a figure which shows schematic structure of the front-end | tip part of the optical scanning endoscope main body of FIG. It is a figure which shows schematic structure of the vibration adjustment part of FIG. It is a perspective view which shows schematic structure of the vibration adjustment part of the optical scanning endoscope apparatus which concerns on 2nd Embodiment. It is an expanded view of the square tube of FIG. It is a figure which shows schematic structure of the vibration adjustment part of the optical scanning endoscope apparatus which concerns on 3rd Embodiment. It is a perspective view which shows schematic structure of the vibration adjustment part of the optical scanning endoscope apparatus which concerns on 4th Embodiment. It is a figure which shows the modification of 4th Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram illustrating a schematic configuration of an optical scanning endoscope apparatus that is an example of the optical scanning apparatus according to the first embodiment. The optical scanning endoscope apparatus 10 includes an optical scanning endoscope body 20, a light source unit 30, a detection unit 40, a drive current generation unit 50, a control unit 60, a display unit 61, and an input unit 62. It is comprised including. The light source unit 30 and the optical scanning endoscope body 20 are optically connected by an illumination optical fiber 11 made of, for example, a single mode fiber. The detection unit 40 and the optical scanning endoscope body 20 are optically connected by a detection optical fiber bundle 12 made of, for example, a multimode fiber. The light source unit 30, the detection unit 40, the drive current generation unit 50, and the control unit 60 may be housed in the same housing, or may be housed in separate housings.

  The light source unit 30 combines light from three laser light sources that emit CW (continuous oscillation) laser light of, for example, three primary colors of red, green, and blue, and emits it as white light. As the laser light source, for example, a DPSS laser (semiconductor excitation solid-state laser) or a laser diode can be used. Of course, the configuration of the light source unit 30 is not limited to this, and a single laser light source or a plurality of other light sources may be used.

  The optical scanning endoscope main body 20 irradiates the observation object 100 with light emitted from the light source unit 30 through the illumination optical fiber 11 while vibrating the emission end of the illumination optical fiber 11 by the scanning unit 21. Then, the object to be observed 100 is two-dimensionally scanned (in this embodiment, raster scanning), and the signal light obtained by the scanning is condensed and transmitted to the detection unit 40 via the detection optical fiber bundle 12. Here, the drive current generation unit 50 supplies a required oscillating current to the scanning unit 21 via the wiring cable 13 based on the control from the control unit 60.

  The detection unit 40 separates the signal light transmitted by the detection optical fiber bundle 12 into spectral components, and photoelectrically converts the separated signal light into an electrical signal. The control unit 60 synchronously controls the light source unit 30, the detection unit 40, and the drive current generation unit 50, processes the electrical signal output by the detection unit 40, and displays an image on the display unit 61. In addition, the control unit 60 performs various settings such as the scanning speed and the brightness of the display image based on the input signal from the input operation from the input unit 62.

  FIG. 2 is a schematic view schematically showing the optical scanning endoscope body 20. The optical scanning endoscope body 20 includes an operation unit 22 and a flexible insertion unit 23. The illumination optical fiber 11 from the light source 30, the detection optical fiber bundle 12 from the detection unit 40, and the wiring cable 13 from the drive current generation unit 50 pass through the inside of the insertion unit 23 to the tip 24 (see FIG. 2). (The portion indicated by a broken line). The distal end portion 24 is bent by the operation portion 22.

  3 (a) and 3 (b) show a schematic configuration of the distal end portion 24 of the optical scanning endoscope main body 20 of FIG. 2, FIG. 3 (a) is a cross-sectional view, and FIG. It is a partial expansion perspective view. The distal end portion 24 is provided with a scanning portion 21, projection lenses 25a and 25b, and a detection lens (not shown) (not shown), and the illumination optical fiber 11 and the detection optical fiber bundle 12 extend. ing.

  The scanning unit 21 includes a square tube 26, coils 27 a to 27 d, and a permanent magnet 28. The square tube 26 is a hollow square columnar tube that extends in the longitudinal direction along the central axis of the distal end portion 24. The rear end portion of the square tube 26 is fixed to the vibration adjusting unit 70. The vibration adjustment unit 70 is fixed in the insertion unit 23 via the support member 29. In addition, instead of the square tube 26, a tube having a cylindrical shape or another shape may be used.

  The illumination optical fiber 11 is supported by the vibration adjusting unit 70 at the exit end via a holding member 11b such as a ferrule. That is, the illumination optical fiber 11 is supported by the vibration adjusting unit 70 so that the exit end protruding from the holding member 11b can vibrate within a certain range. On the other hand, the detection optical fiber bundle 12 is disposed so as to pass through the outer peripheral portion of the distal end portion 24.

  The projection lenses 25 a and 25 b and the detection lens are disposed in the vicinity of the distal end surface of the distal end portion 24. The projection lenses 25 a and 25 b are configured so that the laser light emitted from the emission end face 11 a of the illumination optical fiber 11 is substantially condensed on the object to be observed 100. In addition, the detection lens emits light (light interacting with the object to be observed 100), fluorescence, or the like that is reflected, scattered, or refracted by the object to be observed 100 from the laser light collected on the object to be observed 100. It is taken in as detection light and arranged so as to be condensed and coupled to the detection optical fiber bundle 12 arranged after the detection lens. Note that the projection lens is not limited to a two-lens configuration, and may be composed of one lens or a plurality of other lenses.

  A permanent magnet 28 (magnetic material) magnetized in the axial direction of the illumination optical fiber 11 is disposed in a part between the support portion 11b of the illumination optical fiber 11 and the exit end face 11a. The permanent magnet 28 has a through hole formed in the axial direction of the illumination optical fiber 11, and is bonded and fixed to the illumination optical fiber 11 with the illumination optical fiber 11 passing through the through hole. In addition, coils 27 a to 27 d printed in a spiral shape are arranged at a portion of the square tube 26 facing the one pole of the permanent magnet 28. The coil 27a and the coil 27c are disposed on one opposing surface of the rectangular tube 26, and the coil 27b and the coil 27d are disposed on the other opposing surface of the rectangular tube 26. The line connecting the centers of the coils 27 a and 27 c and the line connecting the centers of the coils 27 b and 27 d are orthogonal to each other in the vicinity of the substantially central axis of the square tube 26.

  The wiring cable 13 from the drive current generation unit 50 passes through the insertion unit 23 and is connected to the coils 27a to 27d. The wiring cable 13 has, for example, two pairs of cables. The coil 27a and the coil 27c are connected in series or in parallel so that a magnetic field in the same direction is generated in one pair of cables. The coil 27a and the coil 27c are supplied with a current having a frequency corresponding to the resonance frequency of the vibrating portion including the emission end of the illumination optical fiber 11 and the permanent magnet 28, for example. The coil 27b and the coil 27d are connected in series or in parallel so that a magnetic field in the same direction is generated in the other pair of cables. The coil 27b and the coil 27d are fed with a current having a frequency lower than the frequency corresponding to the resonance frequency of the vibration part.

  Thereby, a deflection magnetic field is generated in the square tube 26 in the direction of the line connecting the centers of the coils 27a and 27c (for example, the X-axis direction), and the direction of the line connecting the centers of the coils 27b and 27d ( For example, a deflection magnetic field is generated in the Y-axis direction). Then, due to the interaction between the deflection magnetic field in the X-axis direction and the deflection magnetic field in the Y-axis direction and the magnetic flux of the permanent magnet 28, the exit end of the illumination optical fiber 11 vibrates according to the temporal change of each magnetic field strength. The object to be observed 100 is raster-scanned by light emitted through the illumination optical fiber 11.

  In the present embodiment, the vibration adjusting unit 70 is configured to be able to adjust the vibration characteristics of the vibration-receiving portion including the emission end portion protruding from the holding member 11 a of the illumination optical fiber 11 and the permanent magnet 28. Hereinafter, the configuration of the vibration adjusting unit 70 will be described with reference to the schematic diagrams shown in FIGS.

  4A and 4B are a side view and a plan view, respectively, showing the vibration adjusting unit 70 with a part cut away. FIG. 4C is a view of the vibration adjusting unit 70 as viewed from the emission end face 11 a side of the illumination optical fiber 11. The vibration adjusting unit 70 includes a rigid cylindrical member 71 having a square cross section, a yaw direction adjusting screw 72, a pitch direction adjusting screw 73, and an elastic member 74. The yaw direction adjusting screw 72 is screwed to the cylindrical member 71 so as to extend in the X-axis direction. The pitch direction adjusting screw 73 is screwed into the cylindrical member 71 so as to extend in the Y axis direction at a position different from the yaw direction adjusting screw 72 in the axial direction of the cylindrical member 71. The elastic member 74 is disposed between the holding member 11 b and the inner wall surface of the cylindrical member 71 so as to press the holding member 11 b against the respective tips of the yaw direction adjusting screw 72 and the pitch direction adjusting screw 73.

  According to the vibration adjusting unit 70 shown in FIGS. 4A to 4C, the yaw direction adjusting screw 72 is rotated and the yaw direction adjusting screw 72 enters the cylindrical member 71 in a stationary state of the vibrating portion. When the amount is changed, the holding member 11b rotates around the axis of the pitch direction adjusting screw 73, that is, around the Y axis in accordance with the change in the amount of approach. Similarly, when the pitch direction adjustment screw 73 is rotated to change the amount of the pitch direction adjustment screw 73 entering the cylindrical member 71, the holding member 11b adjusts the yaw direction according to the change in the amount of entry. It rotates around the axis of the screw 72, that is, around the X axis. Thereby, the stationary position of the vibrating part can be adjusted around the X axis (pitch or tilt direction) and Y axis (yaw direction) orthogonal to each other in the two-dimensional scanning plane by the illumination optical fiber 11. It is possible to adjust the vibration characteristics of the portion to be vibrated with the vibration start position.

  Therefore, with a simple configuration in which the stationary position of the vibration part is adjusted by the yaw direction adjustment screw 72 and the pitch direction adjustment screw 73, the vibration trajectory of the vibration part, that is, the trajectory of the irradiation light to the object 100 is acquired. In the scanning range, it is possible to adjust the vibration characteristics of the vibrating part so as to be stably orthogonal to the X-axis direction and the Y-axis direction. Note that the adjustment of the vibration characteristics of the portion to be vibrated is performed, for example, by scanning an image using an inspection apparatus or the like prior to incorporating the illumination optical fiber 11 into the optical scanning endoscope body 20. After the adjustment, the adjustment state is fixed and incorporated in the optical scanning endoscope body 20.

  Hereinafter, other embodiments of the present invention will be described. In the following description, components having the same functions as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

(Second Embodiment)
FIG. 5 is a perspective view illustrating a schematic configuration of a vibration adjustment unit of the optical scanning endoscope apparatus according to the second embodiment. In the present embodiment, the rectangular tube 26 is housed and arranged in the cylindrical member 80. As shown in a development view in FIG. 6, the square tube 26 has silicon substrates 82a to 82d on which coils 27a to 27d are respectively formed and mounted at predetermined intervals on a flexible sheet 81 such as polyimide. Then, the silicon substrates 82 a to 82 d are curved at the portion of the flexible sheet 81 and accommodated in the cylindrical member 80 so that each surface of the square tube 26 is formed. The holding member 11 a of the illumination optical fiber 11 is fixed to the support member 29.

  In the vibration adjustment unit 90 according to the present embodiment, an adjustment screw 91 and a coil 27b are formed at the rear end of the cylindrical member 80 so as to be in contact with the silicon substrate 82a on which the coil 27a is formed. And an adjustment screw 92 screwed to come into contact with the silicon substrate 82b. The screwed portions of the adjustment screws 91 and 92 of the cylindrical member 80 are preferably formed in a concave shape so that the heads of the adjustment screws 91 and 92 can be embedded after adjustment.

  The silicon substrate 82 a comes into contact with the tip of the adjustment screw 91 by the bending elastic force of the flexible sheets 81 on both sides. Similarly, the silicon substrate 82b comes into contact with the tip of the adjustment screw 92 by the bending elastic force of the flexible sheets 81 on both sides. Therefore, when the adjustment screw 91 is rotated and the amount of entry into the cylindrical member 80 is changed while the vibration part is stationary, the silicon substrate 82a is shifted in the X-axis direction in accordance with the change in the amount of entry. Or, it is displaced in the yaw direction. When the adjustment screw 92 is rotated to change the amount of entry into the cylindrical member 80, the silicon substrate 82b is shifted in the Y-axis direction or displaced in the pitch direction in accordance with the change in the amount of entry. As a result, the direction of the deflection magnetic field can be adjusted by adjusting the relative position of the permanent magnet 28 and the coils 27a and 27b at the stationary position of the vibration part, so that the stationary position is set as in the case of the first embodiment. It is possible to adjust the vibration characteristics of the portion to be vibrated as the vibration start position.

  As described above, also in the present embodiment, the vibration locus of the portion to be vibrated, that is, the object to be observed 100 is adjusted with a simple configuration in which the relative positions of the permanent magnet 28 and the coils 27a and 27b are adjusted by the adjusting screws 91 and 92. It is possible to adjust the vibration characteristics of the vibrating portion so that the irradiation light trajectory is stably orthogonal to the X-axis direction and the Y-axis direction in the image acquisition scanning range. In addition, the adjustment of the vibration characteristics of the above-described vibrating portion is performed in the same manner as in the first embodiment, for example, before the illumination optical fiber 11 is incorporated into the optical scanning endoscope body 20, an inspection apparatus or the like. This is done by scanning the image using. After the adjustment, the adjustment state is fixed and incorporated in the optical scanning endoscope body 20.

(Third embodiment)
FIGS. 7A and 7B show a schematic configuration of the vibration adjustment unit of the optical scanning endoscope apparatus according to the third embodiment, and FIG. 7A is a cross-sectional view of the vibration part. FIG. 7B is an enlarged perspective view of the vibration part. The vibration adjusting unit 110 according to the present embodiment has a notch 28 a formed in a part of the peripheral surface of the permanent magnet 28. The notch 28a is formed along the extending direction of the illumination optical fiber 11, for example. The holding member 11 a of the illumination optical fiber 11 is fixed to the support member 29.

  Prior to incorporation into the optical scanning endoscope body 20, the illumination optical fiber 11 is rotated by rotating the permanent magnet 28 using, for example, an inspection apparatus or the like, as shown in FIG. 7B. While adjusting the direction of 28a, vibration trajectories in the X-axis direction and the Y-axis direction are adjusted based on the scanning result of the image. Then, after the adjustment of the orientation of the notch portion 28 a of the permanent magnet 28, the adjusted state is fixed and incorporated in the optical scanning endoscope body 20.

  Therefore, also in this embodiment, with a simple configuration, the vibration trajectory of the portion to be vibrated, that is, the trajectory of the irradiation light on the object 100 is stabilized in the X-axis direction and the Y-axis direction in the image acquisition scanning range. It is possible to adjust the vibration characteristics of the portion to be vibrated so as to be orthogonal to each other.

(Fourth embodiment)
FIG. 8 is a perspective view illustrating a schematic configuration of a vibration adjustment unit of the optical scanning endoscope apparatus according to the fourth embodiment. The vibration adjusting unit 120 according to the present embodiment has a scratched part 28 b formed on a part of the peripheral surface of the permanent magnet 28. In other words, the vibration adjusting unit 120 adjusts the vibration characteristics of the vibrating part by adjusting the mass of the vibrating part by forming the scratched part 28 b in a part of the permanent magnet 28. Although not shown, the holding member 11 a of the illumination optical fiber 11 is fixed to the support member 29.

  The wound portion 28b is formed on the basis of a result obtained by scanning an image using an inspection device or the like before the illumination optical fiber 11 is incorporated into the optical scanning endoscope body 20, for example, such as a YAG laser. It is formed by laser light irradiation. Then, after the adjustment, the illumination optical fiber 11 is incorporated into the optical scanning endoscope body 20.

  As described above, in the present embodiment, the vibration adjustment unit 120 is configured by the scratched part 28b formed in a part of the permanent magnet 28 so as to adjust the mass of the part to be vibrated. Thus, the vibration characteristic of the vibration part is set so that the vibration path of the vibration part, that is, the light beam irradiated onto the object 100 is stably orthogonal to the X-axis direction and the Y-axis direction in the image acquisition scanning range. Can be adjusted.

  Note that the vibration adjustment unit 120 that adjusts the mass of the portion to be vibrated is configured, for example, by attaching a mass body 28c such as an adhesive or a solder ball to a part of the peripheral surface of the permanent magnet 28 as shown in FIG. You can also

  The present invention is not limited to the above-described embodiments, and many variations or modifications are possible. For example, in the first embodiment, the vibration part can be adjusted around the X axis and the Y axis, but may be configured to be adjustable only around one of the axes. Similarly, in the second embodiment, only the relative position between one coil and the permanent magnet may be adjustable.

  In addition, the two-dimensional scanning mode of the object to be observed is not limited to raster scanning, and the vibration target may be vibrated so as to perform other scanning such as spiral scanning. In addition, the scanning unit is not limited to an electromagnetic driving method using a permanent magnet and a coil. For example, a piezoelectric driving method in which a piezo element is attached to a vibrating portion and the vibrating portion is vibrated by deformation of the piezo element, or other driving methods. Also good. Furthermore, the present invention can be applied not only to the optical scanning endoscope apparatus but also to other scanning observation apparatuses and scanning apparatuses such as laser processing that do not have an observation function.

DESCRIPTION OF SYMBOLS 10 Optical scanning endoscope apparatus 20 Optical scanning endoscope main body 11 Illumination optical fiber 11a Ejection end surface 11b Holding member 12 Detection optical fiber bundle 13 Wiring cable 21 Scanning part 22 Operation part 23 Insertion part 24 Tip part 25a, 25b Projection lens 26 Square tube 27a to 27d Coil 28 Permanent magnet 28a Notch 28b Wound 28c Mass body 29 Support member 30 Light source 40 Detection unit 50 Drive current generator 60 Control unit 61 Display unit 62 Input unit 70, 90, 110, 120 Vibration adjustment unit 100 Object to be observed

Claims (7)

An optical scanning device that two-dimensionally scans the object by irradiating the object with light emitted from the optical fiber while vibrating the exit end of the optical fiber by a scanning unit,
A vibration adjustment unit that adjusts vibration characteristics of a portion to be vibrated including the emission end of the optical fiber;
An optical scanning device.   The scanning unit includes a permanent magnet that is provided at the exit end of the optical fiber and forms the vibration part together with the exit end, and a plurality of coils arranged around the permanent magnet. Item 4. The optical scanning device according to Item 1.   The vibration adjusting unit adjusts the stationary position of the vibration-receiving portion at least about the first axis or the second axis in the direction orthogonal to the two-dimensional scanning plane of the optical fiber, and the vibration characteristics The optical scanning device according to claim 1, wherein the optical scanning device is adjusted.   3. The optical scanning device according to claim 2, wherein the vibration adjustment unit adjusts the vibration characteristic by adjusting a relative position of at least one of the coils with respect to the permanent magnet at a stationary position of the vibrating portion. .   The optical scanning device according to claim 2, wherein the vibration adjustment unit includes a notch formed in the permanent magnet, and adjusts the vibration characteristic by adjusting a direction of the notch.   The optical scanning device according to claim 2, wherein the vibration adjusting unit adjusts the vibration characteristic by adjusting a mass of the vibrating portion. The optical scanning device according to claim 6, wherein the vibration adjustment unit adjusts the vibration characteristic by adjusting a mass of the permanent magnet.

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