JP2014044265A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanner capable of performing resonance driving in a first direction, and at the same time, performing stable scanning also in a second direction, without requiring complicated control, in optical fiber scanning.SOLUTION: An optical scanner comprises: an optical fiber having a fixing part and an oscillating part 11b oscillatable with respect to the fixing part; and oscillation driving means (28a to 28d) for performing oscillation driving of the oscillating part 11b of the optical fiber. The oscillating part 11b of the optical fiber has different resonance frequencies in X and Y directions orthogonal to an axial direction of the optical fiber, respectively, and the optical fiber performs optical scanning by emitting light from a tip 11c while performing the oscillation driving of the oscillating part 11b.

Description

  The present invention relates to an optical scanning device using a swingable optical fiber.

  Conventionally, an optical scanning type observation device that scans light from the tip of an optical fiber toward an object to be observed and detects light reflected or scattered by the object to be observed or fluorescence generated by a non-observed object. Is known (see, for example, Patent Document 1). In such an apparatus, in order to scan the irradiated light on the object to be observed, a part of the optical fiber is supported in a state where the end portion from which the light is emitted can be swung, and a piezoelectric element is provided in the vicinity of the support portion. Is arranged so that the tip of the optical fiber is deflected by vibrating the optical fiber.

  For example, according to Patent Document 1, two pairs of piezoelectric elements that vibrate an optical fiber in two orthogonal directions (X direction and Y direction) are provided. Then, the optical fiber is driven to vibrate in accordance with the resonance frequency of the oscillating portion supported by the support portion of the optical fiber. By gradually increasing or decreasing the amplitudes of the drive currents in the X and Y directions, the tip of the optical fiber vibrates in a spiral shape and scans the object to be observed. By driving at the resonance frequency, the optical fiber can be greatly bent to perform scanning.

  By the way, not a spiral scan as described above, but a raster scan that scans at a low speed in the second axis direction (Y direction) orthogonal to the first axis direction (X direction) while scanning at a high speed in the first axis direction (X direction), or a Lissajous Scanning may be preferred. However, when the optical fiber is sine vibrated in the first axis direction by resonant driving, it is known that the sine vibration due to the resonance frequency is also caused in the second axis direction, and the scanning line tends to be elliptical rather than straight. It has been. This is because a generally used optical fiber has an axially symmetric structure, and since this is held axially symmetrical, the resonance frequencies in both the first and second axial directions are substantially the same. If a slight force component in the second axial direction occurs during scanning in the first axial direction due to an assembly error of the piezoelectric element, etc., vibration in the second axial direction is greatly amplified by resonance, and This is because a phase difference is generated with respect to vibration in one axial direction.

Special table 2010-527028 gazette

  However, the scanning trajectory on the object to be observed is unstable and distorted even if a low-frequency vibration is further applied in the second axis direction to an optical fiber that generates an elliptical vibration in the second axis direction. It becomes difficult to observe with high accuracy. Further, if control is performed to detect and cancel the vibration of the resonance frequency generated in the second axis direction, there is a concern that the drive control of the apparatus becomes complicated.

  Accordingly, an object of the present invention made by paying attention to these points is that scanning is stable in the second direction while performing resonance driving in the first direction without requiring complicated control in scanning of the optical fiber. An object of the present invention is to provide an optical scanning device capable of performing the above.

The invention of an optical scanning device that achieves the above object
An optical fiber having a fixed portion and a swingable portion swingable with respect to the fixed portion;
Vibration drive means for driving the oscillation portion of the optical fiber to vibrate,
The oscillating part of the optical fiber has different resonance frequencies in a first direction and a second direction perpendicular to the axial direction of the optical fiber, and the optical fiber oscillates the oscillating part. In this state, light scanning is performed by emitting light from the tip of the swinging portion.

  The driving means preferably drives the optical fiber in resonance in the first direction and drives in the second direction at a frequency different from that of the first direction.

  The optical fiber may have a different Young's modulus in the first direction and the second direction.

  For example, the Young's modulus can be made different between the first direction and the second direction by partially coating the optical fiber with a metal film.

  Further, the optical fiber can have a second moment of section different between the first direction and the second direction.

  For example, the optical fiber has a cross-sectional shape having at least a partial four-fold symmetry, so that the second moment of section can be made different between the first direction and the second direction.

  Alternatively, the optical fiber may be attached with a weight having different second-order moments in the first direction and the second direction.

  Further, the vibration driving means includes a magnet coupled to the optical fiber and a plurality of electromagnetic coils that exert a magnetic force on the magnet, and the center of gravity of the magnet is shifted from the axis of the optical fiber. By positioning, the cross-sectional secondary moment can be made different.

  Further, the fixing portion fixes the optical fiber at different positions in the first direction and the second direction, and the length of the swinging portion in the first direction and the second direction. The length can be substantially different.

  Preferably, the vibration driving means drives a vibration having a frequency that does not cause resonance in the second direction.

  More preferably, the scanning locus of the optical scanning has a raster shape.

  Alternatively, the vibration driving unit may drive the optical fiber to resonate in the second direction. In this case, the difference frequency between the resonance frequency in the first direction and the resonance frequency in the second direction can be set in the vicinity of the imaging frame rate, and the scanning trajectory of the optical scanning can have a Lissajous shape.

  According to the present invention, the oscillating portion of the optical fiber has different resonance frequencies in the first direction and the second direction orthogonal to the axial direction of the optical fiber. It is possible to perform stable scanning in the second direction while performing resonance driving in the first direction without requiring control.

1 is a block diagram illustrating a schematic configuration of an optical scanning endoscope apparatus that is an example of an optical scanning observation apparatus according to a first embodiment. FIG. FIG. 2 is an overview diagram schematically showing the optical scanning endoscope main body of FIG. 1. FIG. 3 is a cross-sectional view of a distal end portion of the optical scanning endoscope main body of FIG. 2. 4A is a side view showing a vibration driving mechanism of the optical scanning endoscope apparatus and a swinging portion of the illumination optical fiber, and FIG. 4B is a cross-sectional view taken along line AA in FIG. FIG. 4C is a cross-sectional view taken along the line BB in FIG. FIG. 5A is a side view showing the vibration driving mechanism of the optical scanning endoscope apparatus according to the second embodiment and the oscillating portion of the optical fiber for illumination, and FIG. It is AA sectional drawing of a). FIG. 6A is a side view showing a vibration driving mechanism of the optical scanning endoscope apparatus according to the third embodiment and a swinging portion of the illumination optical fiber, and FIG. It is AA sectional drawing of a). Fig.7 (a) is a side view which shows the rocking | fluctuation part of the optical fiber for illumination of the optical scanning type endoscope apparatus which concerns on 4th Embodiment, FIG.7 (b) is FIG.7 (a). It is AA sectional drawing. FIG. 8A is a side view showing the vibration driving mechanism of the optical scanning endoscope apparatus according to the fifth embodiment and the oscillating portion of the illumination optical fiber, and FIG. FIG. 8A is a cross-sectional view taken along the line AA in FIG. 8A, and FIG. 8C is a cross-sectional view taken along the line BB in FIG. It is an enlarged view which shows the front-end | tip part of the optical scanning type endoscope apparatus which concerns on 6th Embodiment, Fig.9 (a) is sectional drawing of the front-end | tip part, FIG.9 (b) is the scanning of Fig.9 (a). FIG. 9C is a cross-sectional view taken along a plane perpendicular to the axis of the optical fiber of the portion including the deflection magnetic field generating coil and the permanent magnet of FIG. 9B.

  Prior to the description of the embodiment of the present invention, a formula for calculating the resonance frequency of the optical fiber, which is the basis of the present invention, will be described. When the vibration of the oscillating portion (from the fixed end to the tip end portion) of the optical fiber is regarded as simple cantilever vibration, the resonance frequency of the optical fiber is expressed by Expression (1).

Where f _n is the n-th resonance frequency, L is the length of the optical fiber, E is the Young's modulus of the optical fiber, I is the second moment of section, ρ is the density of the optical fiber, and A is the cross-sectional area of the optical fiber. is there. Further, λ _n is a solution of the characteristic equation expressed by the equation (2), and λ ₁ = 1.8751, λ ₂ = 4.66941, λ ₃ = 7.8548, λ ₄ = 10.996,. It is.

  Further, when the cross section of the optical fiber is a circle, the cross-sectional second moment is expressed by Expression (3).

  Therefore, the optical fiber density, Young's modulus, cross-section second moment, and optical fiber length (fixed end position) are different values in the first and second directions orthogonal to each other. In this case, the resonance frequency is different between the first direction and the second direction. The present invention is designed so that the resonance frequencies in the first and second directions orthogonal to each other of the oscillating portion of the optical fiber have different values, so that the vibration is driven by the resonance frequency in one direction. However, it does not affect the vibration in the other direction or reduces the influence.

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

(First embodiment)
FIG. 1 is a block diagram showing a schematic configuration of an optical scanning endoscope apparatus 10 which is an example of an optical scanning observation 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 voltage 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 main body 20 are optically connected by the illumination optical fiber 11 that is a single mode fiber, and the detection unit 40 and the optical scanning endoscope main body 20 are multi-connected. The optical fiber bundle 12 for detection comprised with a mode fiber is optically connected. The light source unit 30, the detection unit 40, the drive voltage 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 three primary colors, for example, red, green, and blue, and emits the light 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 may use one laser light source or other plural light sources.

  The optical scanning endoscope body 20 is obtained by scanning the light emitted from the light source unit 30 by the illumination optical fiber 11 on the object to be observed 100 by the scanning unit 21 (vibration driving unit), and obtained by this scanning. The signal light is collected and transmitted to the detection unit 40 via the detection optical fiber bundle 12. Here, based on control from the control unit 60, the drive voltage generation unit 50 applies an oscillating voltage to the scanning unit 21 via the wiring cable 13.

  The detection unit 40 decomposes the signal light that has passed through the detection optical fiber bundle 12 into spectral components, and converts the signal light into an electrical signal by a photodetector using a photodiode. The control unit 60 synchronously controls the light source unit 30, the detection unit 40, and the drive voltage generation unit 50, processes the electrical signal output by the detection unit 40, combines the images, and displays the images on the display unit 61. Further, various settings such as the scanning speed and the brightness of the display image can be performed on the optical scanning endoscope apparatus 10 from the input unit 62.

  FIG. 2 is a schematic view schematically showing the optical scanning endoscope body 20. The optical scanning endoscope main body 20 includes an operation unit 22 and an insertion unit 23, and one end of the operation unit 22 and one end of the insertion unit 23 are connected and integrated. The operation unit 22 is connected to the illumination optical fiber 11 from the light source unit 30, the detection optical fiber bundle 12 from the detection unit 40, and the wiring cable 13 from the drive voltage generation unit 50. The illumination optical fiber 11, the detection optical fiber bundle 12 and the wiring cable 13 pass through the inside of the insertion portion 23, and a distal end portion 24 (an end portion different from the end portion connected to the operation portion 22 of the insertion portion 23). 2) (the portion within the broken line in FIG. 2).

  3 is an enlarged cross-sectional view of the distal end portion 24 of the insertion portion 23 of the optical scanning endoscope main body 20 of FIG. The distal end portion 24 includes a scanning portion 21, projection lenses 25 a and 25 b, and a detection lens (not shown), and the illumination optical fiber 11 and the detection optical fiber bundle 12 that pass through the insertion portion 23 extend.

  The scanning unit 21 includes an actuator tube 27 fixed inside the insertion unit 23 of the optical scanning endoscope main body 20 by an attachment ring 26, and piezoelectric elements 28a to 28d and a fiber holding member disposed in the actuator tube 27. 29 (see FIGS. 4A and 4B). The illuminating optical fiber 11 is supported by a fiber holding member 29, and a fixed end 11a supported by the fiber holding member 29 to a tip end portion 11c constitute a swinging portion 11b that is swingably supported. On the other hand, the detection optical fiber bundle 12 is disposed so as to pass through the outer peripheral portion of the insertion portion 23, and extends to the distal end of the distal end portion 24.

  Further, the projection lenses 25 a and 25 b and the detection lens are arranged at the forefront of the distal end portion 24. The projection lenses 25 a and 25 b are configured so that the laser light emitted from the distal end portion 11 c 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.

  FIG. 4A is a view showing a vibration driving mechanism of the optical scanning endoscope apparatus 10 and a swinging portion 11b of the illumination optical fiber 11, and FIG. 4B is a cross-sectional view taken along line A- of FIG. A sectional view and FIG.4 (b) are BB sectional drawings of Fig.4 (a). The illumination optical fiber 11 passes through the center of the fiber holding member 29 having a prismatic shape, and is thereby fixed and held by the fiber holding member 29. Therefore, the portion of the illumination optical fiber 11 that passes through the fiber holding member 29 is a fixing portion of the illumination optical fiber 11. The four side surfaces of the fiber holding member 29 are directed in the + Y direction (first direction) and the + X direction (second direction) and in the opposite directions, respectively. The pair of piezoelectric elements 28a and 28c for driving in the Y direction are fixed in the + Y direction and the −Y direction of the fiber holding member 29, and the pair of piezoelectric elements 28b and 28c for driving in the X direction in the + X direction and −X direction. Is fixed.

On the other hand, a part of the oscillating portion 11b of the illumination optical fiber 11 is coated with metal films 71a and 71b in the ± Y direction by sputtering. This coating increases the Young's modulus E _{Y in} the Y direction of the oscillating portion 11b, compared to the Young's modulus EX in the _X direction, so that the resonance frequency in the Y direction is higher than the resonance frequency in the X direction.

  Each of the piezoelectric elements 28a to 28d is connected to the wiring cable 13 from the drive voltage generation unit 50. The drive voltage generation unit 50 can drive the X-direction driving piezoelectric elements 28b and 28d and the Y-direction driving piezoelectric elements 28a and 28c by applying a voltage independently at different vibration frequencies. . When the piezoelectric elements 28a and 28c for driving in the Y direction and the piezoelectric elements 28b and 28d for driving in the X direction are driven to vibrate, the swinging part 11b of the illumination optical fiber 11 vibrates and the tip part 11c is deflected. The laser beam emitted from the tip 11c sequentially scans the surface of the object 100 to be observed.

  With the above configuration, when observation is performed by the optical scanning endoscope apparatus 10, the drive voltage generation unit 50 is driven under the control of the control unit 60 and the scanning unit 21 is connected via the wiring cable 13. An oscillating voltage is applied to the piezoelectric elements 28 a to 28 d constituting the oscillating portion, and the oscillating portion 11 b of the illumination optical fiber 11 is oscillated. At this time, the Y-direction driving piezoelectric elements 28a and 28c are driven to vibrate at a resonance frequency in the Y direction of the swinging portion 11b of the illumination optical fiber 11, for example, several kHz. Further, the piezoelectric elements 28b and 28d for X drive are driven to vibrate at a non-resonant frequency of, for example, about 30 Hz, which is considerably slower than the resonant frequency in the Y direction.

  The control unit 60 causes laser light to be emitted from the light source unit 30 along with application of current by the drive voltage generation unit 50, and emits the laser light from the distal end portion 11 c toward the object to be observed 100 via the illumination optical fiber 11. . The laser beam sequentially scans the object under observation 100 by the deflection of the tip end portion 11c caused by the vibration of the swinging portion 11b of the illumination optical fiber 11.

  Reflected light, scattered light, or light generated from the object to be observed 100 obtained by irradiating the object to be observed 100 with the laser light is collected as detection light by the detection lens and coupled to the detection optical fiber bundle 12. The The detection light is guided to the detection unit 40 by the detection optical fiber bundle 12 and is separated and detected for each wavelength component in the detection unit 40.

  The control unit 60 calculates information on the scanning position on the scanning path from the phase of the oscillating voltage applied by the drive voltage generation unit 50, and from the electrical signal output from the detection unit 40, the object 100 to be observed at the scanning position. Pixel data is obtained. The control unit 60 sequentially stores information on the scanning position and pixel data in a storage unit (not shown), and generates an image of the object to be observed 100 by performing necessary processing such as interpolation processing after the scanning is completed or during the scanning. And displayed on the display unit 61.

  With the above configuration, the optical scanning endoscope apparatus 10 can generate a scanned image of the object 100 to be observed. Here, since the resonance frequency in the X direction of the oscillating portion 11b of the illumination optical fiber 11 is different from the resonance frequency in the Y direction, vibration driving by the resonance frequency in the Y direction causes vibration in the X direction. Even if it causes vibration in the X direction, it attenuates rapidly. For this reason, distortion and swelling in the X direction due to the resonance frequency do not occur. Therefore, it is possible to scan with a raster pattern that scans in the Y direction at high speed and scans in the X direction at a frame rate.

  As described above, according to the present embodiment, the oscillating portion 11b of the illumination optical fiber 11 has different resonance frequencies in the Y direction and the X direction orthogonal to the axial direction of the illumination optical fiber 11. Since it did in this way, in the scanning of the optical fiber 11 for illumination, it becomes possible to perform stable raster scanning at different frequencies in two different axial directions without requiring complicated control.

  In addition, since the pair of piezoelectric elements 28a, 28c for driving in the Y direction and the pair of piezoelectric elements 28b, 28d for driving in the X direction are driven with a voltage having a constant amplitude, the scanning locus is simple and driving is performed. The voltage generator 50 does not require complicated control. Furthermore, the scanned area becomes a rectangular area, and the image can be used without waste. Further, even when images are sampled at equal time intervals, an image with uniform pixels near the center can be obtained.

(Modification)
In the above embodiment, the piezoelectric elements 28b and 28d for driving in the X direction are driven to vibrate at a non-resonant frequency. However, the piezoelectric elements 28b and 28d vibrate at the resonant frequency in the X direction of the oscillating portion 11b of the illumination optical fiber 11. It may be driven. In this case, when the resonance frequency in the X direction is significantly different from the resonance frequency in the Y direction, the scanning locus becomes a raster pattern. When the resonance frequency (f _X ) in the X direction is not very different from the resonance frequency (f _Y ) in the Y direction, the scanning locus becomes a Lissajous pattern, and the difference frequency (f _Y −f _X ) becomes the frame rate.

  Also in this case, it is possible to perform stable scanning at different frequencies in two different axial directions without requiring complicated control, the scanning trajectory is simple, and complicated control is performed in the drive voltage generation unit 50. This is not necessary, and the effect is that the scanned area becomes a rectangular area and the image can be used without waste.

(Second Embodiment)
FIG. 5A is a side view showing the vibration driving mechanism of the optical scanning endoscope apparatus 10 and the swinging portion 11b of the illumination optical fiber 11 according to the second embodiment, and FIG. It is AA sectional drawing of Fig.5 (a). In the second embodiment, in order to make the resonance frequencies of the oscillating portion 11b of the illumination optical fiber 11 different in the X direction and the Y direction, the cross-sectional secondary moments in the X direction and the Y direction are made different. is there. A part of the swing part 11b of the illumination optical fiber 11 is removed by processing such as etching in the ± Y direction part of the cladding part. As a result, the cross section of the swinging part 11b loses symmetry (four-fold symmetry) when rotated by 90 °. By doing so, the sectional secondary moment I _{X in the X} direction becomes larger than the sectional secondary moment I _{Y in the} Y direction. As a result, the resonance frequency in the X direction of the oscillating portion 11b is higher than the resonance frequency in the Y direction. Since other configurations are the same as those of the first embodiment, the same or corresponding components are denoted by the same reference numerals and description thereof is omitted.

  In the present embodiment, the X direction is the first direction, the Y direction is the second direction, the oscillating portion 11b of the illumination optical fiber 11 is oscillated at the resonance frequency in the X direction, and the non-resonance frequency is in the Y direction. By virtue of the vibration, the same operation and effect as in the first embodiment can be obtained.

(Third embodiment)
FIG. 6A is a side view showing the vibration driving mechanism of the optical scanning endoscope apparatus 10 and the swinging portion 11b of the illumination optical fiber 11 according to the third embodiment, and FIG. It is AA sectional drawing of Fig.6 (a). Similarly to the second embodiment, the third embodiment also has different cross-sectional secondary moments in the X direction and the Y direction. For this reason, a rectangular parallelepiped weight 73 is attached to a part of the swinging portion 11 b of the illumination optical fiber 11. The weight 73 is provided with a hole that allows the illumination optical fiber 11 to pass through, and the width in the X direction is longer in the XY cross section than in the Y direction in a state where the weight 73 is attached to the swinging portion 11 b of the illumination optical fiber 11. Yes. By doing so, the sectional secondary moment I _{X in the X} direction becomes larger than the sectional secondary moment I _{Y in the} Y direction. As a result, the resonance frequency in the X direction of the oscillating portion 11b is higher than the resonance frequency in the Y direction. Other configurations are the same as those of the first and second embodiments. As a result, the X direction is the first direction and the Y direction is the second direction, and the same operations and effects as in the first and second embodiments can be obtained.

(Fourth embodiment)
Fig.7 (a) is a perspective view which shows the rocking | fluctuation part 11b of the optical fiber 11 for illumination of the optical scanning endoscope apparatus 10 which concerns on 4th Embodiment, FIG.7 (b) is FIG. It is AA sectional drawing of a). In the fourth embodiment, as in the second and third embodiments, the cross-sectional secondary moments in the X direction and the Y direction are different. For this reason, the rocking | swiveling part 11b of the optical fiber 11 for illumination has an elliptical shape whose cross section is longer in the X direction than in the Y direction. By doing so, the sectional secondary moment I _{X in the X} direction becomes larger than the sectional secondary moment I _{Y in the} Y direction. As a result, the resonance frequency in the X direction of the oscillating portion 11b is higher than the resonance frequency in the Y direction. Other configurations are the same as those in the first to third embodiments. As a result, the X direction is the first direction and the Y direction is the second direction, and the same operations and effects as in the first to third embodiments are obtained.

(Fifth embodiment)
FIG. 8A is a side view showing the vibration driving mechanism of the optical scanning endoscope apparatus 10 and the swinging portion 11b of the illumination optical fiber 11 according to the fifth embodiment, and FIG. 8A is a cross-sectional view taken along line AA, and FIG. 8C is a cross-sectional view taken along line BB in FIG. 8A. In the fifth embodiment, the length of the swinging portion 11b in the X direction and the length in the Y direction is changed by changing the application location of the adhesive 75 of the member that holds the illumination optical fiber 11 between the X direction and the Y direction. Are substantially different.

  For this reason, the adhesive 75 between the fiber holding member 29 and the illuminating optical fiber 11 is placed in the X direction at the emission-side end portion (BB cross-sectional position) of the illuminating optical fiber 11 with respect to the fiber holding member 29. It is applied so as to be biased, and this position is a fixed end in vibration in the X direction. In addition, at the end of the illumination optical fiber 11 on the incident side with respect to the fiber holding member 29 (A-A cross-sectional position), the adhesive 75 between the fiber holding member 29 and the illumination optical fiber 11 is placed in the Y direction. It is applied so as to be biased, and this position is a fixed end in the vibration in the Y direction. As a result, the resonance frequency in the X direction becomes larger than the resonance frequency in the Y direction. As another method, both the incident side end portion (position of the A-A cross section) and the exit side end portion (position of the BB cross section) of the illumination optical fiber 11 of the holding member 29 have X A rectangular hole that is approximately equal to the diameter of the optical fiber in the direction and longer than the diameter of the optical fiber is provided in the Y direction, and an adhesive is filled in the gap between the holes only at the incident side end (AA cross section side). , It may be fixed so as not to swing in the Y direction. As a result, the optical fiber is held at the emission side end of the holding member 29 in the X direction, and held at the incident side end of the holding member in the Y direction. Also in this case, the resonance frequency in the X direction can be increased with respect to the resonance frequency in the Y direction by changing the holding positions in the X direction and the Y direction.

  Also in this embodiment, the X direction is the first direction, the Y direction is the second direction, the oscillating portion 11b of the illumination optical fiber 11 is oscillated at the resonance frequency in the X direction, and the non-resonance frequency is in the Y direction. By virtue of the vibration, the same actions and effects as in the first to fourth embodiments can be obtained.

(Sixth embodiment)
In the sixth embodiment, the scanning unit 21 in the first embodiment is configured using a permanent magnet and a deflection magnetic field generating coil (electromagnetic coil) instead of a piezoelectric element. FIG. 9 is an enlarged view showing the distal end portion 24 of the optical scanning endoscope apparatus 10 according to the sixth embodiment. FIG. 9A is a cross-sectional view of the distal end portion 24, and FIG. 9A is an enlarged perspective view showing the scanning unit 21 in FIG. 9A, and FIG. 9C is for illuminating a portion including the deflection magnetic field generating coils 82a to 82d and the permanent magnet 83 in FIG. 9B. 3 is a cross-sectional view taken along a plane perpendicular to the axis of the optical fiber 11. FIG.

  A permanent magnet 83 magnetized in the axial direction of the illumination optical fiber 11 and having a through hole penetrates a part of the oscillation part 11b of the illumination optical fiber 11, and the oscillation part 11b of the illumination optical fiber 11 penetrates. Bonded through the hole. In addition, a square tube 81 having one end fixed to the mounting ring 26 is provided so as to surround the swinging portion 11b, and on each side surface of the square tube 81 at a portion facing one pole of the permanent magnet 83, , Spiral deflection magnetic field generating coils 82a to 82d are provided.

  A pair of deflection magnetic field generation coils 82a and 82c in the Y direction (second direction) and a pair of deflection magnetic field generation coils 82b and 82d in the X direction (first direction) are opposite surfaces of the square tube 81, respectively. The line connecting the center of the deflection magnetic field generating coil 82a and the center of the deflection magnetic field generating coil 82c, and the line connecting the center of the deflection magnetic field generating coil 82b and the center of the deflection magnetic field generating coil 82d are stationary. It is orthogonal in the vicinity of the central axis of the square tube 81 in which the illumination optical fiber 11 is disposed.

  In addition, a drive current generator (not shown) for applying a current to the deflection magnetic field generating coils 82a to 82d is provided in place of the drive voltage generator 50, and each deflection magnetic field generation coil 82a is connected by the wiring cable 13. To 82d.

As shown in FIG. 9C, the hole through which the swinging portion 11 b of the illumination optical fiber 11 in the permanent magnet 83 passes is shifted in the Y direction, and the center of gravity of the permanent magnet 83 is the illumination optical fiber 11. It is located off the axis. In this way, the cross-sectional secondary moment I _X in the X direction becomes larger than the cross-sectional secondary moment I _{Y in the} Y direction. As a result, the resonance frequency in the X direction of the oscillating portion 11b is higher than the resonance frequency in the Y direction. Since other configurations are the same as those of the first to fifth embodiments, the same or corresponding components are denoted by the same reference numerals and description thereof is omitted. Also in the present embodiment, since the resonance frequencies of the oscillating portion 11b of the illumination optical fiber 11 are different between the X direction and the Y direction, the same effects as those of the first to fifth embodiments can be obtained.

  In addition, this invention is not limited only to the said embodiment, Many deformation | transformation or a change is possible. For example, as a modification of the first embodiment, the example in which the oscillating portion 11b of the illumination optical fiber 11 is driven to vibrate in the second direction at the resonance frequency in the second direction has been described. Similarly, in the sixth embodiment, the oscillating portion 11b of the illumination optical fiber 11 can be resonantly driven at the resonance frequency in each direction in both the X direction and the Y direction orthogonal to each other. In the above embodiment, the direction having the higher resonance frequency among the orthogonal X direction and Y direction is the first direction, and the object to be observed is scanned at the resonance frequency in the first direction. It is also possible to scan at a resonance frequency in the lower direction and to scan at a non-resonance frequency in the higher resonance frequency direction. Furthermore, the vibration driving means is not limited to a method using a coil and a magnet or a method using a piezo element, and other vibration driving means may be used. The scanning device of the present invention can be applied not only to an endoscope device but also to other devices such as a microscope.

DESCRIPTION OF SYMBOLS 10 Optical scanning endoscope apparatus 20 Optical scanning endoscope main body 11 Illumination optical fiber 11a Fixed end 11b Oscillating part 11c Tip part 12 Detection optical fiber bundle 13 Wiring cable 21 Scanning part 22 Operation part 23 Insertion part 24 End portion 25a, 25b Projection lens 26 Mounting ring 27 Actuator tube 28a-28d Piezoelectric element 29 Fiber holding member 30 Light source 40 Detection unit 50 Drive voltage generation unit 60 Control unit 61 Display unit 62 Input unit 71a, 71b Metal film 73 Weight 75 Adhesive 81 Square tube 82a to 82d Coil for generating a deflection magnetic field 83 Permanent magnet 100 Object to be observed

Claims (13)

An optical fiber having a fixed portion and a swingable portion swingable with respect to the fixed portion;
Vibration drive means for driving the oscillation portion of the optical fiber to vibrate,
The oscillating part of the optical fiber has different resonance frequencies in a first direction and a second direction perpendicular to the axial direction of the optical fiber, and the optical fiber oscillates the oscillating part. An optical scanning device that performs optical scanning by emitting light from the tip of the oscillating portion in a state of being performed.   2. The optical scanning device according to claim 1, wherein the driving unit resonates the optical fiber in the first direction and drives the optical fiber in the second direction at a frequency different from that of the first direction.   The optical scanning device according to claim 1, wherein the optical fiber has different Young's modulus in the first direction and the second direction.   The optical scanning device according to claim 3, wherein the optical fiber has the Young's modulus different between the first direction and the second direction by partially coating a metal film. .   3. The optical scanning device according to claim 1, wherein the optical fiber has a second moment of section different between the first direction and the second direction. 4.   The optical fiber has a cross-sectional shape having at least a partial four-fold symmetry, and the second-order moment of the cross-section is made different between the first direction and the second direction. Item 6. The optical scanning device according to Item 5.   3. The optical scanning device according to claim 1, wherein weights having different second-order moments in the first direction and the second direction are attached to the optical fiber.   The vibration driving means includes a magnet coupled to the optical fiber and a plurality of electromagnetic coils that exert a magnetic force on the magnet, and the center of gravity of the magnet is located offset from the axis of the optical fiber. The optical scanning device according to claim 1, wherein the second moment of section is made different.   The fixing portion fixes the optical fiber at different positions in the first direction and the second direction, and the length of the swinging portion in the first direction and the length in the second direction The optical scanning device according to claim 1, wherein substantially different from each other.   The optical scanning device according to claim 1, wherein the vibration driving unit drives vibration having a frequency that does not cause resonance in the second direction.   The optical scanning device according to claim 10, wherein a scanning locus of the optical scanning has a raster shape.   The optical scanning device according to claim 1, wherein the vibration driving unit drives the optical fiber to resonate in the second direction.   The optical scanning device according to claim 12, wherein a difference frequency between the resonance frequency in the first direction and the resonance frequency in the second direction is set in the vicinity of an imaging frame rate, and a scanning locus of the optical scanning is a Lissajous shape.