JP2017058418A - Optical scanning device and endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanning device capable of properly detecting a rotational angle of a mirror.SOLUTION: An optical scanning device comprises: a first beam extending in a first direction; a first reflective part coupled with the first beam and configured to be rotatable about the first beam; first and second driving parts provided to face each other, partially sandwiching both ends of the first reflective part in a second direction that is different from the first direction; a first detection unit provided on a the same side as the first driving part in the first reflective part, at a position corresponding to a position on the first reflective part that is different from a position corresponding to the first driving part in the first direction; and a first shielding part provided on the same side as the first driving part at a position corresponding to a position on the first reflective part between the positions corresponding to the first driving part and the first detection part, and is configured to prevent capacitive coupling between the first detection part and the first driving part.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an optical scanning device and an endoscope.

Conventionally, it is known to rotate and vibrate with a torsion beam as a rotation axis to deflect a light beam (see, for example, Patent Document 1). Further, an optical scanning device that scans a beam two-dimensionally by using two mirrors that rotate around a rotation axis is known (for example, see Patent Document 2).
[Prior art documents]
[Patent Literature]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2004-069731 [Patent Document 2] Japanese Translation of PCT International Application No. 2008-514977

  In the optical scanning device, a drive electrode electrically connected to an AC power source is provided close to the mirror so as to rotationally drive the mirror. The optical scanning device is provided with a detection electrode in the vicinity of the mirror in order to detect the rotation angle of the mirror. Since the detection electrode and the drive electrode are provided close to each other, a drive signal sent from the AC power source to the drive electrode may interfere with the detection electrode. In this case, there is a problem that the detection electrode cannot correctly detect the rotation angle of the mirror.

  (General Disclosure of Invention) An optical scanning device may include a first beam portion extending in a first direction. The optical scanning device may include a first reflecting portion that is connected to the first beam portion and can rotate around the first beam portion as a rotation axis. In the second direction, which is a direction different from the first direction, the optical scanning device includes a first drive unit and a second drive unit that are provided to face each other while partially sandwiching both ends of the first reflection unit. May be provided. The optical scanning device is provided on the same side of the first reflecting unit as the first driving unit, and corresponds to the position of the first reflecting unit in the first direction different from the position corresponding to the first driving unit. You may provide the 1st detection part provided. The optical scanning device is provided on the same side as the first drive unit, and corresponds to the position of the first reflection unit between the position corresponding to the first drive unit and the position corresponding to the first detection unit. And a first shield part that prevents capacitive coupling between the first detection part and the first drive part.

  The 1st reflection part may have a plurality of comb teeth at both ends in the 2nd direction. Each of the first drive unit and the second drive unit may include two or more equal numbers of comb teeth that are spaced apart from the plurality of comb teeth of the first reflection unit. The comb teeth of the first driving unit and the second driving unit may be provided at positions symmetrical with respect to the first direction passing through the first beam unit.

  The optical scanning device does not have to include the detection unit on the same side as the second drive unit in the first reflection unit.

  The optical scanning device may further include a dummy unit. The dummy part has a ground potential, is provided on the same side as the second driving part in the first reflecting part, and the first reflecting part in the first direction different from the position corresponding to the second driving part. It may be provided corresponding to the position. The first shield part, the first detection part, and the dummy part may have the same number of comb teeth, and may be provided at positions symmetrical with respect to the first direction passing through the first beam part.

  The optical scanning device may further include a charge-voltage conversion circuit. The charge-voltage conversion circuit may include an amplifier and a capacitor. The amplifier may have a non-inverting input terminal that is electrically grounded. The amplifier may have an inverting input terminal electrically connected to the first detection unit. The amplifier may have an output terminal. The capacitor may have one end electrically connected to the inverting input terminal and the other end electrically connected to the output terminal.

  The optical scanning device may further include a second detection unit. The second detection unit is provided on the same side as the second drive unit in the first reflection unit, and corresponds to the position of the first reflection unit in the first direction different from the position corresponding to the second drive unit. May be provided.

  The optical scanning device may further include a second shield part. The second shield part is provided on the same side as the second drive part, and is located at the position of the first reflection part between the position corresponding to the second drive part and the position corresponding to the second detection part. It may be provided correspondingly.

  The optical scanning device may further include a second beam portion extending in the second direction. The optical scanning device may further include a second reflecting unit. The second reflecting portion is connected to the second beam portion, and is provided adjacent to the second driving portion rather than the first driving portion at a position away from the first reflecting portion. It may be possible to rotate about the part as a rotation axis.

  The optical scanning device may further include a third driving unit and a fourth driving unit. The third driving unit and the fourth driving unit may be provided to face each other with the both ends of the second reflecting unit partially sandwiched in the first direction. The optical scanning device may further include a third detection unit. The third detection unit is provided on the same side as the third drive unit in the second reflection unit, and the position of the second reflection unit in a second direction different from the position corresponding to the third drive unit. It may be provided corresponding to. The optical scanning device may further include a fourth detection unit. The fourth detection unit is provided on the same side of the second reflection unit as the fourth drive unit, and corresponds to the position of the second reflection unit in the second direction different from the position corresponding to the fourth drive unit. May be provided. The optical scanning device may further include a third shield unit positioned between the third drive unit and the third detection unit in the second direction. The optical scanning device may further include a fourth shield unit positioned between the fourth drive unit and the fourth detection unit in the second direction.

  The endoscope may be equipped with the optical scanning device described above.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

1 is a diagram showing an outline of an endoscope system 400. FIG. FIG. 3 is a diagram showing a YZ section of the optical scanning device 200. It is a top view of Y scanner 20 and X scanner 60 in a 1st embodiment. (A) And (B) is an enlarged view of a part including comb teeth 28-1, 38-1, 48-3, and 58-3 of the Y scanner 20. It is a figure explaining the detection of a rotation angle. It is a top view of Y scanner 20 and X scanner 60 in a 2nd embodiment. It is a top view of Y scanner 20 and X scanner 60 in a 3rd embodiment. It is a top view of Y scanner 20 and X scanner 60 in the 1st comparative example.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention. In this specification, technical matters will be described using orthogonal coordinate axes of the X axis, the Y axis, and the Z axis. The Cartesian coordinate axis only specifies the relative position of the component, and does not limit a specific direction. For example, the Z axis does not limit the height direction with respect to the ground. Note that the + Z-axis direction and the −Z-axis direction are directions opposite to each other. When the Z axis direction is described without describing positive and negative, it means a direction parallel to the + Z axis and the −Z axis.

  FIG. 1 is a diagram showing an outline of an endoscope system 400. The endoscope system 400 of this example includes an endoscope 300, a laser light source 310, a dichroic mirror 320, a light detection unit 330, an AD conversion unit 340, an image processing unit 350, and a display unit 360. In addition, this example is an exemplary configuration of the endoscope system 400, and the endoscope system 400 may have a configuration other than that shown here.

  The endoscope 300 includes a non-scanning optical device 210, a forceps port 220, a light 230, and a nozzle 240. The optical scanning device 200 is used by being inserted into the forceps port 220 and is a device different from the endoscope 300. The optical scanning device 200 may be mounted on the endoscope 300. The optical scanning device 200 will be described in detail in FIG. The optical scanning device 200 can scan light on the focal plane 510 (XY plane) of the object 500. The non-scanning optical device 210 is a normal optical device that cannot scan light in the XY plane.

  The object 500 may be a part of a human or other animal body. The forceps port 220 is an opening through which forceps for excising a part of the object 500 can enter and exit. The light 230 may be used to illuminate the object 500. The nozzle 240 has a function of supplying water or blowing air. A plurality of nozzles 240 may be provided according to the number of functions.

  The laser light source 310 generates light that serves as the light source of the optical scanning device 200. The laser light source 310 of this example outputs a laser beam 312 having a wavelength of 488 nm. The output of the laser light source 310 may be less than 1000 mW.

  The dichroic mirror 320 has a function of reflecting the laser light 312. The reflected laser beam 312 enters the optical fiber 19 of the optical scanning device 200, and enters the object 500 through the optical scanning device 200.

  The object 500 absorbs the laser light 312 and emits fluorescence 314. The object 500 of this example has a fluorescent material that absorbs the laser light 312 in the blue band (wavelength conversion of about 435 nm to 500 nm) and emits the fluorescence 314 in the green band (wavelength conversion of about 500 nm to 560 nm). This situation can be realized by introducing a fluorescent material into the body of a human or other animal.

  The fluorescence 314 emitted from the object 500 enters the light detection unit 330 through the optical scanning device 200, the optical fiber 19, and the dichroic mirror 320. Note that the dichroic mirror 320 of this example has a function of transmitting the fluorescence 314.

  The light detection unit 330 detects fluorescence from the object 500. The light detection unit 330 may include a photoelectric conversion device such as a photodiode. The light detection unit 330 generates an electric charge according to the intensity of the fluorescence 314. For example, the higher the intensity of the fluorescence 314, the more charges are generated.

  The AD conversion unit 340 includes an analog / digital converter that converts the amount of charge, which is analog information, into a digital signal. The AD conversion unit 340 outputs a digital signal to the image processing unit 350, and the image processing unit 350 generates an image based on the digital signal. In this example, the image processing unit 350 generates a Lissajous scan image from the digital signal, and the display unit 360 displays the Lissajous scan image. The user can visually recognize the focal plane 510 of the object 500 from the Lissajous scanning image.

  FIG. 2 is a diagram illustrating a YZ cross section of the optical scanning device 200. The optical scanning device 200 includes a tube 10, a flange 12, an objective lens 16, a collimating lens 17, a scanner unit 100, and a wiring board 106. In this specification, the Z-axis direction is a direction parallel to the optical axis direction of the objective lens 16. In FIG. 2, the description of the fluorescence 314 is omitted.

  The tube 10 is a tube that extends in the Z-axis direction. The length of the tube 10 in the Z-axis direction is desirably a length that can be moved while bending in the body of a human or other animal. The length of the tube 10 in the Z-axis direction may be 10 mm to 20 mm. Further, the outer diameter of the tube 10 may be 3.0 mm.

  The wiring board 106 is provided inside the tube 10. On the wiring substrate 106 of this example, the lens holder 14, the scanner unit 100, the lens holder 18, and a plurality of IC chips 108 are placed. In the present specification, the + Y-axis direction is referred to as “up” or “upward” for convenience, and the −Y-axis direction is referred to as “down” or “downward” for convenience.

  An objective lens 16 is fixedly provided on the lens holder 14. The objective lens 16 focuses the laser beam 312 emitted from the scanner unit 100 on the focal plane 510.

  The scanner unit 100 is placed on the wiring board 106. The scanner unit 100 includes a fixed mirror 102 and an SOI (Silicon On Insulator) substrate 104. The fixed mirror 102 has a plurality of reflecting surfaces. The fixed mirror 102 of this example has three reflecting surfaces.

  The SOI substrate 104 is provided with a plurality of reflecting portions. In this example, the plurality of reflecting portions are formed from the active layer of the SOI substrate 104. The light incident from the collimating lens 17 is reflected between the reflecting surface of the fixed mirror 102 and the reflecting portion of the SOI substrate 104 and is finally emitted from the objective lens 16.

  Each of the plurality of reflecting portions can be rotated and vibrated. The scanner unit 100 can scan the laser beam 312 in the X direction and the Y direction by reflecting the laser beam 312 with a plurality of reflection units.

  A collimating lens 17 is fixedly provided on the lens holder 18. The collimating lens 17 converts the laser light 312 emitted from the optical fiber 19 into parallel light. The flange 12 fixes the optical fiber 19. Thereby, the cross-sectional center of the optical fiber 19 and the optical axes of the collimating lens 17 and the objective lens 16 can be matched.

  The IC chip 108 may have an angle detection function for detecting the rotation angle of the reflection unit, a noise removal function, and an operational amplifier function. By placing both the scanner unit 100 and the IC chip 108 on the wiring board 106, they can be placed in close physical proximity. Thereby, a minute voltage signal that is easily buried in noise can be captured more accurately.

  FIG. 3 is a top view of the Y scanner 20 and the X scanner 60 in the first embodiment. The SOI substrate 104 includes a Y scanner 20 and an X scanner 60. The Y scanner 20 and the X scanner 60 disclosed in this example can be formed by patterning an SOI substrate by applying a known etching technique.

  (Y Scanner 20) The Y scanner 20 includes a beam portion 21 as a first beam portion, a first fixing portion 22-1 and a second fixing portion 22-2, and a reflecting portion as a first reflecting portion. 24. In this example, a metal layer such as aluminum having a thickness of 100 nm is provided on the surface in the + Y-axis direction of the reflector 24 to reflect light. The Y scanner 20 includes a drive unit 32-1 and 32-2 as a first drive unit and a second drive unit, and a detection unit 52-1 as a first, second, fifth, and sixth detection unit. To 52-4, and shield portions 42-1 to 42-4 as first, second, fifth and sixth shield portions.

  (Fixed portion 22, reflecting portion 24, comb tooth 28) The beam portion 21 extends in the X-axis direction as the first direction. Beam portions 21 are connected to both ends of the reflection portion 24 in the X-axis direction. The reflection part 24 can rotate with the beam part 21 as a rotation axis. The reflection unit 24 has a plurality of comb teeth 28 at both ends in the Z-axis direction as the second direction. Since the 2nd direction of this example is a Z-axis direction, it is a direction different from a 1st direction (X-axis direction), and is a direction orthogonal. The beam portion 21, the fixing portion 22, the reflection portion 24, and the comb teeth 28 in this example are formed from an active layer of the SOI substrate 104.

  (Driver 32, Comb Teeth 38) In this example, the driver 32-1 as the first driver is provided facing the position 35 of the end 26-1 of the reflector 24 in the + Z-axis direction. It is done. Further, the driving unit 32-2 as the second driving unit is provided at a position symmetrical to the driving unit 32-1 with respect to the X-axis direction passing through the beam unit 21. The drive units 32-1 and 32-2 are provided to face each other with the both ends of the reflection unit 24 partially interposed therebetween.

  The drive unit 32-1 has two or more comb teeth 38-1 provided apart from the plurality of comb teeth 28 of the reflection unit 24. The driving unit 32-2 is also provided so as to be separated from the comb teeth 28, and has two or more comb teeth 38-2 in the same number as the comb teeth 38-1. The comb teeth 38 are arranged so as to mesh with the comb teeth 28 of the reflecting portion 24. The comb teeth 38-1 and 38-2 are provided at positions symmetrical with respect to the X-axis direction passing through the beam portion 21.

  (Capacitance formation by comb teeth 28 and 38) The comb teeth 38 of the drive unit 32 and the comb teeth 28 of the reflection unit 24 do not contact each other. The comb teeth 38 do not contact the reflecting portion 24, and the comb teeth 28 do not contact the driving portion 32. Thus, the comb teeth 28 and the comb teeth 38 form a capacitance with air interposed therebetween.

  A DC voltage is applied to the reflecting portion 24 of this example via a pad (indicated by a square frame in FIG. 3) at the ± X-axis direction end portion of the fixed portion 22. In addition, the beam part 21, the fixing | fixed part 22, and the reflection part 24 are electrically connected. In addition, an alternating voltage is applied to the drive unit 32 of this example via a pad (indicated by a square frame in FIG. 3) at the end in the ± X axis direction. The pad may be a metal thin film layer such as aluminum. Due to the electrostatic force acting between the comb teeth 28 and the comb teeth 38, the reflecting portion 24 rotates and vibrates about the beam portion 21 as a rotation axis. In this example, the reflecting part 24 rotates the beam part 21 by making the electrostatic capacity of the driving part 32-1 and the reflecting part 24 equal to the electrostatic capacity of the driving part 32-2 and the reflecting part 24. The shaft can rotate and vibrate in a balanced manner from side to side.

  (Detection unit 52, comb tooth 58) The detection unit 52-1 is provided on the same side as the drive unit 32-1 in the reflection unit 24. Further, the detection unit 52-1 is provided corresponding to a position 55 different from the position 35 corresponding to the drive unit 32-1 in the reflection unit 24. The position 35 and the position 55 are different positions in the X-axis direction of the end portion 26 of the reflecting portion 24.

  The detection unit 52-1 as the first detection unit and the detection unit 52-2 as the second detection unit are provided at positions symmetrical with respect to the X-axis direction passing through the beam portion 21. The detection unit 52-2 is provided on the same side of the reflection unit 24 as the drive unit 32-2. The detection unit 52-2 is provided corresponding to the position of the reflection unit 24 in the X-axis direction different from the position corresponding to the drive unit 32-2. The detection unit 52-1 has comb teeth 58-1, and the detection unit 52-2 has comb teeth 58-2.

  The fifth detection unit 52-2 is provided at a position symmetrical to the detection unit 52-1 with respect to the drive unit 32-1. The sixth detection unit 52-4 is provided at a position symmetrical to the detection unit 52-2 with respect to the drive unit 32-2. The detection unit 52-3 and the detection unit 52-4 are provided at positions symmetrical with respect to the X-axis direction passing through the beam portion 21. The detector 52-3 has comb teeth 58-3, and the detector 52-4 has comb teeth 58-4.

  In this example, after each of the detection units 52-1 to 52-4 is electrically connected, a change in capacitance between the detection unit 52 and the reflection unit 24 is detected. The principle of detection will be described later with reference to FIG.

  (Capacity formation by the comb teeth 28 and the comb teeth 58) The comb teeth 58 of the detection unit 52 and the comb teeth 28 of the reflection unit 24 do not contact each other. The comb teeth 58 do not contact the reflection unit 24, and the comb teeth 28 do not contact the detection unit 52. Thereby, the comb teeth 28 and the comb teeth 58 form a capacitance with air sandwiched therebetween.

  The electrostatic capacitance of the comb teeth 28 and the comb teeth 58 changes according to the fact that the reflecting portion 24 rotates and vibrates about the beam portion 21 as a rotation axis. The detection unit 52 transmits the change in capacitance to a subsequent circuit. The detection unit 52 of this example has a pad (indicated by a square frame in FIG. 3) at an end in the ± X axis direction. The detection unit 52 outputs a change in charge according to a change in capacitance between the comb teeth 28 and the comb teeth 58 as an input current signal Iin to a subsequent circuit.

  (Shield part 42) The shield part 42-1 as the first shield part is provided on the same side as the drive part 32-1. The shield part 42-1 is provided corresponding to a position 45 between the position 35 and the position 55 of the reflecting part 24. The shield part 42 of this example is grounded and maintains the GND potential. Therefore, the shield unit 42 has a function of preventing capacitive coupling between the detection unit 52 and the drive unit 32. Thereby, compared with the case where the shield part 42 is not provided, it can reduce that the signal of the alternating voltage input into the drive part 32 interferes with the detection part 52 as noise.

  The shield part 42-2 as the second shield part is provided on the same side as the drive part 32-2. The shield part 42-2 is provided corresponding to the position of the reflection part 24 between the position of the reflection part 24 to which the drive part 32-2 corresponds and the position of the reflection part 24 to which the detection part 52-2 corresponds. The shield part 42-1 has comb teeth 48-1, and the shield part 42-2 has comb teeth 48-2.

  The fifth shield part 42-3 is provided at a position symmetrical to the shield part 42-1 with respect to the drive part 32-1. Further, the sixth shield part 42-4 is provided at a position symmetrical to the shield part 42-2 with respect to the drive part 32-2. The shield part 42-3 and the shield part 42-4 are provided at positions symmetrical with respect to the X-axis direction passing through the beam part 21. The shield part 42-3 has comb teeth 48-3, and the shield part 42-4 has comb teeth 48-4.

  (X Scanner 60) The shape of the X scanner 60 is different from that of the Y scanner 20. However, the X scanner 60 is functionally a scanner in which the Y scanner 20 is rotated 90 degrees on the XZ plane. Therefore, the Y scanner 20 and the X scanner 60 are common in many respects. Description of functions common to the Y scanner 20 is omitted.

  The X scanner 60 includes a beam portion 61 as a second beam portion, a third fixing portion 62-1 and a fourth fixing portion 62-2, and a reflecting portion 64 as a second reflecting portion. The X scanner 60 includes a drive unit 72-1 and 72-2 as a third drive unit and a fourth drive unit, and a detection unit 52-1 as a third, fourth, seventh, and eighth detection unit. To 52-4, and shield portions 42-1 to 42-4 as third, fourth, seventh and eighth shield portions.

  (Fixed portion 62, reflecting portion 64, comb tooth 68) The reflecting portion 64 is adjacent to the driving portion 32-2 rather than the driving portion 32-1 of the Y scanner 20 at a position away from the reflecting portion 24 on the XZ plane. Provided. The beam portion 61 extends in the Z-axis direction as the second direction. Beam portions 61 are connected to both ends of the reflecting portion 64 in the Z-axis direction. The reflection part 64 can rotate with the beam part 61 as a rotation axis. The reflecting portion 64 has a plurality of comb teeth 68 at both ends in the X-axis direction. The beam portion 61, the fixing portion 62, the reflecting portion 64, and the comb teeth 68 in this example are also formed from the active layer of the SOI substrate 104.

  In this example, the reflection unit 64 of the X scanner 60 is provided in the vicinity of the drive unit 32-2 of the Y scanner 20. Thereby, in this example which has the drive part 32, the shield part 42, and the detection part 52, the space | interval of the reflection part 24 of the Y scanner 20 and the reflection part 64 of the X scanner 60 can be minimized. As a result, the size of the optical scanning device 200 in the Z-axis direction can be reduced.

  (Driver 72, Comb 78) In this example, the driver 72-1 as the third driver is opposed to the position 75 of the end 66-1 of the reflector 64 in the -X-axis direction. Provided. The drive unit 72-2 as the fourth drive unit is provided at a position symmetrical to the drive unit 72-1 with respect to the Z-axis direction passing through the beam unit 61. The drive units 72-1 and 72-2 are provided to face each other with the both ends of the reflection unit 64 partially sandwiched in the X-axis direction.

  The drive unit 72-1 has two or more comb teeth 78-1 provided apart from the plurality of comb teeth 68 of the reflection unit 64. The drive unit 72-2 is also provided so as to be separated from the comb teeth 68, and has two or more comb teeth 78-2 as many as the comb teeth 78-1. The comb teeth 78 are arranged so as to mesh with the comb teeth 68 of the reflecting portion 64. The comb teeth 78-1 and 78-2 are provided at positions symmetrical with respect to the Z-axis direction passing through the beam portion 61.

  (Detection unit 92, comb tooth 98) The detection unit 92-1 is provided on the same side as the drive unit 72-1 in the reflection unit 64. The detection unit 92-1 is provided corresponding to a position 95 different from the position 75 corresponding to the driving unit 72-1 in the reflection unit 64. The position 75 and the position 95 are different positions in the Z-axis direction of the end portion 66 of the reflecting portion 64.

The detection unit 92-1 as the third detection unit and the detection unit 92-2 as the fourth detection unit are provided at positions symmetrical with respect to the Z-axis direction passing through the beam unit 61. The detection unit 92-2 is provided on the same side of the reflection unit 64 as the drive unit 72-2. The detection unit 92-2 is provided corresponding to the position of the reflection unit 64 in the Z-axis direction different from the position corresponding to the driving unit 72-2. The detection unit 92-1 has comb teeth 98-1, and the detection unit 92-2 has comb teeth 98-2.
(Shield part 82) The shield part 82-1 as the third shield part is located between the drive part 72-1 and the detection part 92-1 in the Z-axis direction. The shield part 82-2 as the fourth shield part is located at a position 85 between the drive part 72-2 and the detection part 92-2 in the Z-axis direction. The shield part 82-1 has comb teeth 88-1, and the shield part 82-2 has comb teeth 88-2.

  The shield part 83-3 as the seventh shield part is provided at a position symmetrical to the shield part 82-1 with respect to the drive part 72-1. The shield part 82-4 as the eighth shield part is provided at a position symmetrical to the shield part 82-2 with respect to the drive part 72-2. The shield part 82-3 and the shield part 82-4 are provided at positions symmetrical with respect to the Z-axis direction passing through the beam part 61. The shield part 82-3 has comb teeth 88-3, and the shield part 82-4 has comb teeth 88-4.

  4A and 4B are enlarged views of a portion including the comb teeth 28-1, 38-1, 48-3, and 58-3 of the Y scanner 20. FIG. In this example, the Y scanner 20 will be described, but the same applies to the X scanner 60. In this example, the thickness of the active layer of the reflection part 24 and the detection part 52 is the same. Therefore, the lowermost part of the active layer of the reflector 24 and the detector 52 is set as a reference position.

  (A) shows a state where the rotation angle is 0 degree. In (A), the lowermost portions of the active layers of the reflecting portion 24 and the detecting portion 52 are coincident with each other. (B) shows a state where the rotation angle is θ (≠ 0) degrees. In (B), the lowermost part of the reflecting part 24 and the lowermost part of the detecting part 52-3 form an angle θ with the beam part 21 as the rotation axis.

  In (A), the area where the reflection part 24 and the detection part 52-3 overlap in the X-axis direction is the maximum. Therefore, when the rotation angle is 0 degree, the capacitance formed by the reflection unit 24 and the detection unit 52-3 becomes the maximum value. On the other hand, the reflection part 24 rotates about the beam part 21 as the rotation axis (the rotation angle becomes ± θ degrees), and the area where the reflection part 24 and the detection part 52-3 overlap in the X-axis direction decreases. . Therefore, as the reflecting unit 24 rotates, the capacitance formed by the reflecting unit 24 and the detecting unit 52-3 decreases.

  FIG. 5 is a diagram illustrating detection of the rotation angle. In this example, the Y scanner 20 will be described, but the same rotation angle detection mechanism can also be applied to the X scanner 60.

A direct current voltage is applied to the reflecting portion 24 through the fixed portion 22. The reflective portion 24 and the detection unit 52 forms a capacitor _{C 1.} Incidentally, a detection unit 52 and the shield portion 42 to form a capacitor _{C 2.} The shield portion 42 and the drive unit 32 to form a capacitor _{C 3.} An AC voltage is applied to the drive unit 32, but since the shield unit 42 is grounded, capacitive coupling between the drive unit 32 and the detection unit 52 is prevented.

In the capacitor _{C 1,} the potential difference _{V 1} of the between the detector 52 and the reflecting portion 24 does not change. In contrast, the capacitance of the capacitor C ₁ with the rotation of the reflecting portion 24 is changed. This is referred to as ΔC _1. In response to a change in capacitance in the capacitor C _1, a change in charge Q ₁ at the capacitor C _1. Let this be ΔQ ₁ . Therefore, the information on the rotation angle of the reflection unit 24 is converted into information on ΔQ ₁ . Let ΔQ ₁ per unit time be the input current signal Iin.

  The optical scanning device 200 of this example includes a charge / voltage conversion circuit 120. The charge voltage conversion circuit 120 converts the input current signal Iin into an output voltage signal Vout. The charge voltage conversion circuit 120 outputs the output voltage signal Vout to the control unit 125.

  The charge-voltage conversion circuit 120 of this example includes an amplifier 110 and a capacitor 119. The amplifier 110 has a non-inverting input terminal 112, an inverting input terminal 114, and an output terminal 116. The non-inverting input terminal 112 is electrically grounded, and the inverting input terminal 114 is electrically connected to the detection unit 52.

One end of the capacitor 119 is electrically connected to the inverting input terminal 114, and the other end is electrically connected to the output terminal 116. In this example, (also shown as _{C 4.)} Capacitor 119 capacitance of unchanged. That is, the capacitance of the capacitor 119 is fixed. When the charge by the input current signal Iin is charged / discharged, the charge _{Q 4} of the capacitor 119 is changed. This is shown as ΔQ _4. In response to a change in the charge amount in the capacitor 119, the voltage _{V 4} changes in the capacitor 119. This is shown as ΔV ₄ . Thereby, the input current signal Iin is converted into the output voltage signal Vout.

  One end of the resistor 118 is electrically connected to the inverting input terminal 114, and the other end is electrically connected to the output terminal 116. The resistor 118 may have a high resistance value of about MΩ to GΩ. The resistor 118 in this example has a resistance value of 1 GΩ. Therefore, the resistor 118 can function as a negative feedback path of the amplifier 110 without passing the DC component of the input current signal Iin. Since the inverting input terminal 114 and the non-inverting input terminal 112 are virtually grounded, the detection unit 52 can be regarded as a ground potential.

The control unit 125 can convert the information on Vout into information on the rotation angle. For example, when ΔC ₁ decreases due to an increase in the absolute value of rotation angles | ± θ |, ΔQ ₁ decreases. In this case, since the decrease of ΔQ ₁ moves to the capacitor C ₄ , both ΔQ ₄ and ΔV ₄ increase. In this example, since the positive voltage of the DC power source to the reflecting portion 24 is applied, if the [Delta] C ₁ decreases, the negative electric charge of the capacitor C ₄ is increased, Delta] Q ₄ and [Delta] V ₄ increases. Therefore, Vout increases. That is, when the absolute value of rotation angle | ± θ | increases, Vout increases, and when the absolute value of rotation angle | ± θ | decreases, Vout decreases. Vout is converted into the rotation angle of the reflection unit 24 using the correspondence. Note that the control unit 125 may change the voltage value of the AC power supply in accordance with the magnitude of the rotation angle. For example, in order to increase the maximum deflection angle of the rotation angle, the control unit 125 increases the voltage value of the AC power supply.

  FIG. 6 is a top view of the Y scanner 20 and the X scanner 60 in the second embodiment. The Y scanner 20 of the optical scanning device 200 of this example does not have the second shield part 42-2 and the sixth shield part 42-4. Accordingly, the comb teeth 58-2 of the second detection unit 52-2 and the comb teeth 58-4 of the sixth detection unit 52-4 are replaced by the comb teeth 58-2 and the comb teeth 58- of the first embodiment. More than 4. This is different from the first embodiment. Other points are the same as in the first embodiment.

  In this example, since the second shield part 42-2 and the sixth shield part 42-4 are not provided, the reflecting part 24 and the reflecting part 64 can be brought closer to those of the first embodiment. Therefore, the size of the optical scanning device 200 in the Z-axis direction can be further reduced as compared with the first embodiment.

  FIG. 7 is a top view of the Y scanner 20 and the X scanner 60 in the third embodiment. The Y scanner 20 of the optical scanning device 200 of this example does not have the detection units 52-2 and 52-4 on the same side as the drive unit 32-2 in the reflection unit 24. In this example, instead of the detection units 52-2 and 52-4, a dummy part 132-1 as a first dummy part and a dummy part 132-2 as a second dummy part are provided. This is different from the second embodiment. Other points are the same as in the second embodiment.

  The dummy parts 132-1 and 132-2 have a ground potential. The dummy parts 132-1 and 132-2 are provided on the same side of the reflecting part 24 as the driving part 32-2. The dummy part 132-1 is provided corresponding to the position 135 of the reflecting part 24 different from the position 35-2 of the reflecting part 24 to which the driving part 32-2 corresponds. The position 35-2 and the position 135 are different positions in the X-axis direction. The dummy part 132-2 is provided at a position symmetrical to the dummy part 132-1 with respect to the driving part 32-2.

  Each of the dummy portions 132-1 and 132-2 has comb teeth 138-1 and 138.2. The shield part 42-1 and the detection part 52-1 and the dummy part 132-1 have the same number of comb teeth. In this example, there are one comb tooth 48-1 of the shield part 42-1 and one comb tooth 58-1 of the detection part 52-1 and two comb teeth 138-1 of the dummy part 132-1. . Further, the comb teeth 48-1, the comb teeth 58-1 and the comb teeth 138-1 are provided at positions symmetrical with respect to the X-axis direction passing through the beam portion 21.

  In the second embodiment, the detection units 52-2 and 52-4 and the drive unit 32-2 may be capacitively coupled, and noise may interfere with the detection units 52-2 and 52-4. On the other hand, in this example, since the detection units 52-2 and 52-4 are eliminated, there is no noise interference from the drive unit 32-2 to the detection unit on the drive unit 32-2. In addition, as described in the description of FIG. 5, the detection unit 52 can be regarded as a ground potential. Accordingly, the detection units 52-1 and 52-2, the shield units 42-1 and 42-2, and the dummy units 132-1 and 132-2 are all at the ground potential. Thereby, the electrostatic capacity can be made equal in the + Z-axis direction and the −Z-axis direction with the beam portion 21 interposed therebetween.

  Specifically, the electrostatic capacity formed by the shield part 42-1 and the detection part 52-1 and the reflecting part 24 is equal to the electrostatic capacity formed by the dummy part 132-1 and the reflecting part 24. In addition, the electrostatic capacity formed by the shield part 42-3 and the detection part 52-3 and the reflecting part 24 is equal to the electrostatic capacity formed by the dummy part 132-2 and the reflecting part 24. Furthermore, the capacitance formed by the drive unit 32-1 and the reflection unit 24 is equal to the capacitance formed by the drive unit 32-2 and the reflection unit 24. Thereby, it is possible to prevent the driving force to the reflecting portion 24 from becoming unbalanced in the + Z-axis direction and the −Z-axis direction with the beam portion 21 interposed therebetween.

  FIG. 8 is a top view of the Y scanner 20 and the X scanner 60 in the first comparative example. In this example, the Y scanner 20 does not have the dummy part 132. Instead, the driving unit 32-2 has comb teeth 38-2 corresponding to all of the comb teeth 28-2 of the reflecting unit 24. This is different from the third embodiment. In this example, noise from the driving unit 32-2 does not interfere in the detection unit, but the driving force to the reflecting unit 24 is unbalanced in the + Z axis direction and the −Z axis direction with the beam unit 21 interposed therebetween. There is a problem of becoming.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  10 .. Tube, 12 .. Flange, 14 .. Lens holder, 16 .. Objective lens, 17 .. Collimating lens, 18 .. Lens holder, 19 .. Optical fiber, 20 .. Y scanner, 21. , 22 .. Fixing part, 24 .. Reflection part, 26 .. End part, 28 .. Comb tooth, 32 .. Drive part, 35 .. Position, 38 .. Comb tooth, 42. .. Position, 48 .. Comb tooth, 52 .. Detection part, 55 .. Position, 58 .. Comb tooth, 60 .. X scanner, 61 .. Beam part, 62 .. Fixed part, 64. , 66 .. End, 68 .. Comb tooth, 72 .. Drive part, 75 .. Position, 78 .. Comb tooth, 82 .. Shield part, 85 .. Position, 88 .. Comb tooth, 92. Detection unit, 95 ... position, 98 ... comb, 100 ... scanner unit, 102 ... fixed mirror, 104 ... SOI substrate 106 .. Wiring board, 108 .. IC chip, 110... Amplifier, 112 .. Non-inverting input terminal, 114 .. Inverting input terminal, 116 .. Output terminal, 118 .. Resistance, 119. · Charge voltage conversion circuit 125 ·· Control unit 132 · · Dummy unit 135 · · Position 138 · · Comb teeth 200 · · Optical scanning device 210 · · Non-scanning optical device 220 · · Forceps port 230, Light, 240, Nozzle, 300, Endoscope, 310, Laser light source, 312, Laser light, 314, Fluorescent, 320, Dichroic mirror, 330, Light detector, 340 · AD conversion unit, 350 ·· Image processing unit, 360 · · Display unit, 400 · · Endoscope system, 500 · · Object, 510 · · Focal plane

Claims (10)

A first beam portion extending in a first direction;
A first reflecting portion connected to the first beam portion and capable of rotating about the first beam portion as a rotation axis;
A first driving unit and a second driving unit provided in a second direction, which is different from the first direction, by partially sandwiching both ends of the first reflecting unit and facing each other;
Provided on the same side as the first drive unit in the first reflection unit, corresponding to the position of the first reflection unit in a first direction different from the position corresponding to the first drive unit. A first detection unit,
Corresponding to the position of the first reflecting part between the position corresponding to the first driving part and the position corresponding to the first detecting part, provided on the same side as the first driving part. An optical scanning device, comprising: a first shield unit that is provided and prevents capacitive coupling between the first detection unit and the first drive unit. The first reflecting portion has a plurality of comb teeth at both ends in the second direction,
Each of the first driving unit and the second driving unit has two or more equal number of comb teeth provided apart from the plurality of comb teeth of the first reflecting unit,
2. The optical scanning device according to claim 1, wherein the comb teeth of the first driving unit and the second driving unit are provided at positions symmetrical with respect to the first direction passing through the first beam unit. .   3. The optical scanning device according to claim 1, wherein a detection unit is not provided on the same side of the first reflection unit as the second drive unit. 4. The first reflection unit has a ground potential, is provided on the same side as the second drive unit in the first reflection unit, and is different from the corresponding position of the second drive unit in the first direction. A dummy portion provided corresponding to the position;
The first shield part, the first detection part, and the dummy part have the same number of comb teeth and are provided at positions symmetrical with respect to the first direction passing through the first beam part. The optical scanning device according to claim 1. An electrically grounded non-inverting input terminal;
An inverting input terminal electrically connected to the first detection unit;
An amplifier having an output terminal;
5. The charge-voltage conversion circuit according to claim 1, further comprising: a capacitor having one end electrically connected to the inverting input terminal and the other end electrically connected to the output terminal. Optical scanning device.   Provided on the same side as the second driving unit in the first reflecting unit, corresponding to the position of the first reflecting unit in a first direction different from the position corresponding to the second driving unit. The optical scanning device according to claim 1, further comprising a second detection unit.   Corresponding to the position of the first reflection unit between the position corresponding to the second drive unit and the position corresponding to the second detection unit, provided on the same side as the second drive unit The optical scanning device according to claim 6, further comprising a second shield portion provided. A second beam portion extending in the second direction;
The second beam part is connected and provided at a position away from the first reflection part, more adjacent to the second drive part than the first drive part, and the second beam part is The optical scanning device according to claim 1, further comprising a second reflecting portion that can rotate as a rotation axis. A third drive unit and a fourth drive unit that are provided so as to face each other partially sandwiching both ends of the second reflection unit in the first direction;
Provided on the same side as the third drive unit in the second reflection unit, corresponding to the position of the second reflection unit in the second direction different from the position corresponding to the third drive unit. A third detector,
Provided corresponding to the position of the second reflecting portion in the second direction, which is provided on the same side as the fourth driving portion in the second reflecting portion, and is different from the corresponding position of the fourth driving portion. A fourth detector,
A third shield part located between the third drive part and the third detection part in the second direction;
9. The optical scanning device according to claim 8, further comprising a fourth shield portion positioned between the fourth driving unit and the fourth detection unit in the second direction.   An endoscope equipped with the optical scanning device according to any one of claims 1 to 9.

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