JP2017058419A - Optical scanning device and endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanning device which is not negatively affected by reduction in mechanical strength of a mirror surface caused by recesses evenly distributed on a back surface of a mirror.SOLUTION: An optical scanning device has a first beam extending in a first direction and a first reflective part coupled with one end of the first beam and configured to be rotatable about the first beam. The first reflective part has a reflective surface for reflecting light and a back surface on a side opposite the reflective surface, and recesses formed by selectively removing portions of the back surface, and is configured such that volume of the recesses gradually increases from a first axis of the first reflective part, extending in the first direction through the first beam, toward edges of the first reflective part that are farthest from the first axis.SELECTED DRAWING: Figure 4

Description

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

As one of MEMS (Micro Electro Mechanical Systems), an optical scanning device having a reflecting surface is known. Conventionally, a through hole has been provided in a reflective surface (see, for example, Patent Documents 1 and 2). Conventionally, regular quadrangular pyramid recesses are uniformly arranged in a lattice pattern on the back surface of the reflecting surface (see, for example, Patent Document 3).
[Prior art documents]
[Patent Literature]
[Patent Document 1] JP-A-2006-321017 [Patent Document 2] JP-A 2009-213068 [Patent Document 3] JP-A-2011-064964

  When the reflective surface has a through hole, a problem arises because stray light is generated by the through hole. In addition, when the concave portions are provided uniformly on the back surface of the reflecting surface, there is a problem because the mechanical strength of the optical scanning device that rotates is lowered.

  (General Disclosure of Invention) An optical scanning device is connected to a first beam portion extending in a first direction and one end of the first beam portion, and can rotate around the first beam portion as a rotation axis. A first reflection unit. The first reflection unit may include a reflection surface that reflects light, a back surface that is located on the opposite side of the reflection surface, and a concave portion in which a part of the back surface is selectively removed. The volume of the concave portion extends from the first shaft portion of the first reflecting portion that passes through the first beam portion and extends in the first direction to the end portion of the first reflecting portion that is farthest from the first shaft portion. May increase.

  The recess may have a plurality of holes having a predetermined depth. The number of the plurality of holes may increase from the first shaft portion to the end portion of the first reflecting portion.

  The plurality of holes may be arranged symmetrically with respect to the first shaft portion.

  The plurality of holes may increase in density in the first direction from the first shaft portion to the end of the first reflecting portion.

  Each of the plurality of holes may have an equal volume. Each of the plurality of holes may be provided at a predetermined pitch in the first direction and the second direction orthogonal to the first direction.

  Each of the plurality of holes may be a cylinder or a prism.

  Each of the plurality of holes may not penetrate through to the reflection surface of the first reflection unit.

  The plurality of holes may not be provided in the first shaft portion.

  The plurality of holes may include a first hole, a second hole, and a third hole. The first hole may be provided at a position corresponding to a driving unit that rotates and vibrates the first reflecting unit. The second hole may be provided at a position corresponding to a detection unit that detects the rotation angle of the first reflection unit. The third hole may be provided at a position corresponding to the shield part that prevents capacitive coupling between the drive part and the detection part. The volume of the first hole may be smaller than the volume of the second hole. The volume of the second hole may be smaller than the volume of the third hole.

  The concave portion may continuously increase in volume from the first shaft portion to the end portion of the first reflecting portion.

  The optical scanning device may further include a second beam portion and a hanging frame portion. The second beam portion may extend in a second direction orthogonal to the first direction. The hanging frame portion may be connected to the other end of the first beam portion and one end of the second beam portion. The hanging frame portion may be able to rotate about the second beam portion as a rotation axis. The volume of the recess increases from the second shaft portion of the first reflecting portion that extends in the second direction through the second beam portion to the end portion of the first reflecting portion that is parallel to the second direction. It's okay.

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

  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 X scanner 20 and Y scanner 120 in the 1st example. 2 is a view showing a back surface 34 of the X scanner 20. FIG. It is a figure which shows the AA 'cross section of FIG. It is a figure explaining the detection of a rotation angle. It is a figure which shows the back surface 34 of (A) X scanner 20, and (B) BB 'cross section in a 1st modification. It is a figure which shows the back surface 34 of the X scanner 20 in a 2nd modification. It is a figure which shows the back surface 34 of the X scanner 20 in a 3rd modification. It is a figure which shows the back surface 34 of the X scanner 20 in 2nd Example. It is a figure which shows the back surface 34 of (A) X scanner 20, and (B) CC 'cross section in 3rd Example. It is a top view of the biaxial scanner 80 in 4th Example. It is a figure which shows the back surface 94 of the biaxial scanner 80. FIG.

  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.

  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 may output 488 nm laser light 312. 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 may include a fluorescent material that absorbs the laser light 312 in the blue band (about 435 nm to 500 nm in terms of wavelength) and emits the fluorescence 314 in the green band (about 500 nm to 560 nm in terms of wavelength). 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. In FIG. 2, the description of the fluorescence 314 is omitted. 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 direction as the first direction is a direction parallel to the optical axis direction of the objective lens 16. The X direction as the second direction and the Y direction as the third direction are both directions perpendicular to the Z direction. The X direction and the Y direction are also perpendicular to each other. The X direction, the Y direction, and the Z direction form a so-called right-handed system. Each direction only specifies the relative position of the component, and does not limit the specific direction. For example, the Z direction does not limit the height direction with respect to the ground. The + Z direction and the −Z direction are directions opposite to each other. When the positive and negative are not described and the Z direction is simply described, it means a direction parallel to the + Z direction and the −Z direction. In this example, it is assumed that the SOI (Silicon On Insulator) substrate 104 in the scanner unit is on the XZ plane.

  The tube 10 is a tube extending in the Z direction. The length of the tube 10 in the Z direction may be a length that can move while bending in the body of a human or other animal. The length of the tube 10 in the Z 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 this specification, the + Y direction is referred to as “up” or “upward” for convenience, and the −Y 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 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 has an X scanner 20 and a Y scanner 120. The X scanner 20 and the Y scanner 120 may be formed by patterning the active layer of the SOI substrate 104 by applying a known etching technique. The light incident from the collimating lens 17 is reflected between the reflecting surface of the fixed mirror 102 and the X scanner 20 and the Y scanner 120 and finally emitted from the objective lens 16.

  Each of the X scanner 20 and the Y scanner 120 can rotate and vibrate. The X scanner 20 and the Y scanner 120 reflect the laser light 312 while rotating and vibrating. Thereby, the scanner unit 100 can scan the laser beam 312 in the X direction and the Y direction on the focal plane 510.

  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 X scanner 20 and the Y scanner 120 in the first embodiment. The X scanner 20 includes a first reflecting portion 21 and a first beam portion 22 extending in the Z direction. The first reflecting portion 21 is connected to one end 23 of the first beam portion 22 and can rotate around the first beam portion 22 as a rotation axis.

  The first reflecting unit 21 has a reflecting surface 24 that reflects light. The reflective surface 24 may be formed by providing a metal layer such as aluminum having a thickness of 100 nm on the + Y direction side of the first reflective portion 21 made of silicon. The reflecting surface 24 is also rotated by the rotation of the first reflecting portion 21.

  The first reflecting portion 21 has a first shaft portion 26. The first shaft portion 26 passes through the first beam portion 22 and extends in the Z direction. That is, the first shaft portion 26 is located on the extension line of the first beam portion 22. The first shaft portion 26 is a portion serving as a rotation axis of the first reflecting portion 21. The first shaft portion 26 in this example has the same thickness as the thickness of the active layer of the SOI substrate 104. The thickness means the thickness in the Y direction. The first reflecting portion 21 has a plurality of comb teeth at the end portion 28 at a position farthest from the first shaft portion 26 in the X direction.

  The X scanner 20 includes a fixed unit 42, a drive unit 52, a shield unit 62, and a detection unit 72. The fixed portion 42 is connected to the other end opposite to the one end 23 of the first beam portion 22. The fixing part 42 mechanically supports the first reflecting part 21 via the first beam part 22.

  The drive unit 52, the shield unit 62, and the detection unit 72 are symmetrical with respect to the first shaft portion 26 and are provided to face the end portion 28 of the first reflection unit 21. The comb teeth included in each of the drive unit 52, the shield unit 62, and the detection unit 72 are provided so as to mesh with the comb teeth of the first reflection unit 21. However, the comb teeth do not contact each other. Accordingly, the comb teeth of the drive unit 52, the shield unit 62, and the detection unit 72 and the comb teeth of the first reflection unit 21 form a capacitance with air interposed therebetween.

  The driving unit 52 rotates and vibrates the first reflecting unit 21. For example, an AC voltage is applied to the driving unit 52 and a DC voltage is applied to the first reflecting unit 21. As a result, an electrostatic force is generated between the comb teeth, so that the first reflecting portion 21 can oscillate with the first beam portion 22 as the rotation axis.

  The detection unit 72-1 and the detection unit 72-3 in this example are provided at positions symmetrical to the drive unit 52-1. Similarly, the detection unit 72-2 and the detection unit 72-4 are provided at symmetrical positions with respect to the drive unit 52-2. The detection unit 72 is provided to detect a change in electrostatic capacitance between the comb teeth of the detection unit 72 and the comb teeth of the first reflection unit 21. The change in capacitance is transmitted from the detection unit 72 to the subsequent circuit. The detection of the change in capacitance will be described in detail with reference to FIG.

  The shield part 62 is provided between the drive part 52 and the detection part 72. The shield part 62 of this example is grounded and maintains the GND potential. Therefore, the shield part 62 has a function of preventing capacitive coupling between the detection part 72 and the drive part 52. Thereby, compared with the case where the shield part 62 is not provided, it can reduce that the signal of the alternating voltage input into the drive part 52 interferes with the detection part 72 as noise.

  The Y scanner 120 is a scanner obtained by rotating the X scanner 20 by 90 degrees in the XZ plane. Since the Y scanner 120 and the X scanner 20 are common in many respects, descriptions of common functions are omitted.

  The Y scanner 120 includes a second reflecting portion 121 and a second beam portion 122 extending in the X direction. The second reflecting portion 121 is connected to one end 123 of the second beam portion 122, and can rotate around the second beam portion 122 as a rotation axis. The second reflecting portion 121 has a second shaft portion 126 that passes through the second beam portion 122 and extends in the X direction. The second reflecting portion 121 has a second reflecting surface 124, a second shaft portion 126, and a second end portion 128.

  The Y scanner 120 includes a fixed unit 142, a drive unit 152, a shield unit 162, and a detection unit 172. The functions of the fixing unit 142, the driving unit 152, the shield unit 162, and the detecting unit 172 are the same as those of the fixing unit 42, the driving unit 52, the shield unit 62, and the detecting unit 72 of the X scanner 20.

  FIG. 4 is a view showing the back surface 34 of the X scanner 20. Note that the comb teeth are omitted in consideration of the visibility of the drawing. The first reflecting portion 21 has a back surface 34 and a recess 30 provided on the back surface 34. The back surface 34 is a surface located on the opposite side of the reflecting surface 24. In the present specification, the + Y direction of the first reflecting portion 21 is the reflecting surface 24 and the −Y direction is the back surface 34. For the sake of explanation, the first shaft portion 26 is also shown on the back surface 34. The concave portion 30 is a portion where a part of the back surface 34 is selectively removed. The recess 30 in this example has a plurality of holes 32.

In the present example, the plurality of holes 32 are arranged symmetrically with respect to the first shaft portion 26. Further, each of the plurality of holes 32 has an equal opening area. In this example, each of the plurality of holes 32 has a cylindrical shape having a circular opening. Each of the plurality of holes 32, in the Z direction and the X direction, are provided at a pitch P _X and P _Z predetermined. Each of the plurality of holes 32 has an equal volume.

  In this example, the number of the plurality of holes 32 increases from the first shaft portion 26 to the end portion 28, so that the volume of the concave portion extends from the first shaft portion 26 to the end portion 28 of the first reflecting portion 21. Will increase. That is, the number of holes 32 in the first shaft portion 26 is smaller than the number of holes 32 in the vicinity of the end portion 28.

  In this example, when the holes 32 are uniformly provided in the vicinity of the first shaft portion 26 and the end portion 28, and the number of the holes 32 in the first shaft portion 26 is the number of the holes 32 in the vicinity of the end portion 28. The mechanical strength of the first shaft portion 26 can be increased as compared with the case where the number of the first shaft portions 26 is larger. In addition, as compared with the case where the number of holes 32 in the first shaft portion 26 is larger than the number of holes 32 in the vicinity of the end portion 28, the moment of inertia around the first shaft portion 26 in the first reflecting portion 21. Can be reduced more effectively. In addition, since the moment of inertia can be effectively reduced, the power consumption required for driving the first reflecting portion 21 can be reduced.

  Further, in this example, since the plurality of holes 32 are arranged symmetrically with respect to the first shaft portion 26, the moment of inertia can be targeted with respect to the first shaft portion 26. In the etching process, a regular pattern is easier to create than an irregular pattern. In this example, since the holes 32 are provided at a predetermined regular pitch, the hole 32 can be easily created.

  FIG. 5 is a view showing a cross section taken along line AA ′ of FIG. The plurality of holes 32 have a predetermined depth 33. For example, the back surface 34 can be half-etched to form a hole 33 having a depth 33 and a flat bottom surface. In this example, the bottom surface is a surface parallel to the XZ plane on the reflecting surface 24 side of the hole 32. Each of the plurality of holes 32 does not penetrate to the reflecting surface 24 of the first reflecting portion 21. Thereby, generation | occurrence | production of a stray light can be prevented.

  FIG. 6 is a diagram illustrating detection of the rotation angle. In this example, the X scanner 20 will be described, but the same rotation angle detection mechanism can also be applied to the Y scanner 120. The detection unit 72 may be any of the detection unit 72-1 to the detection unit 72-4.

A DC voltage is applied to the first reflecting portion 21 of this example through the fixing portion 42. The detection unit 72 and the first reflection portion 21 to form a capacitor _{C 1.} Incidentally, a detection unit 72 and the shield portion 62 to form a capacitor _{C 2.} A shield portion 62 and the drive unit 52 to form a capacitor _{C 3.} An AC voltage is applied to the drive unit 52, but since the shield unit 62 is grounded, capacitive coupling between the drive unit 52 and the detection unit 72 is prevented.

In the capacitor _{C 1,} the potential difference _{V 1} of the between the detector 72 and the first reflecting portion 21 does not change. In contrast, the capacitance of the capacitor C ₁ with the rotation of the first reflecting part 21 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 first reflection unit 21 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 110. The charge voltage conversion circuit 110 converts the input current signal Iin into an output voltage signal Vout. The charge voltage conversion circuit 110 outputs the output voltage signal Vout to the control unit 119.

  The charge-voltage conversion circuit 110 of this example includes an amplifier 112 and a capacitor 118. The amplifier 112 has a non-inverting input terminal 113, an inverting input terminal 114, and an output terminal 115. The non-inverting input terminal 113 is electrically grounded, and the inverting input terminal 114 is electrically connected to the detection unit 72.

One end of the capacitor 118 (also shown as C ₄ ) is electrically connected to the inverting input terminal 114, and the other end is electrically connected to the output terminal 115. In this example, the capacitance of the capacitor 118 does not change. That is, the capacitance of the capacitor 118 is fixed. When the charge by the input current signal Iin is charged / discharged, the charge _{Q 4} of the capacitor 118 is changed. This is shown as ΔQ _4. In response to a change in the charge amount in the capacitor 118, the voltage _{V 4} changes in the capacitor 118. This is shown as ΔV ₄ . As a result, the information of ΔQ ₁ is converted into the information of ΔV ₄ , so that the input current signal Iin is converted into the output voltage signal Vout.

  One end of the resistor 116 is electrically connected to the inverting input terminal 114 and the other end is electrically connected to the output terminal 115. The resistor 116 may have a high resistance value of about MΩ to GΩ. The resistor 116 in this example has a resistance value of 1 GΩ. Therefore, the resistor 116 can function as a negative feedback path of the amplifier 112 without passing the DC component of the input current signal Iin.

The control unit 119 can convert the Vout information into rotation angle information. For example, when ΔC ₁ decreases due to an increase in the rotation angle, 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 first reflecting part 21 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 rotation angle increases, Vout increases, and when the rotation angle decreases, Vout decreases. Vout is converted into a rotation angle of the first reflecting unit 21 using the correspondence. Note that the control unit 119 may change the voltage value of the AC power supply according to the magnitude of the rotation angle. For example, the control unit 119 increases the voltage value of the AC power supply to increase the maximum deflection angle of the rotation angle.

  FIG. 7 is a diagram illustrating (A) the back surface 34 of the X scanner 20 and (B) a BB ′ cross section in the first modification. In this example, each of the plurality of holes 32 is a prism. This is different from the first embodiment. The other points are the same as in the first embodiment. The hole 32 in this example is a quadrangular prism, but the prism is not limited to a quadrangular prism and may be a polygon having five or more vertices. Similar to the first embodiment, the hole 32 having the depth 33 can be formed by half-etching the back surface 34.

  As a further modification of the first modification, a plurality of holes 32 adjacent in the Z direction may be connected to form a strip shape. In this case, three strips having different lengths in the Z direction are formed on both sides of the first shaft portion 26. Thereby, you may make it the volume of the recessed part 30 increase discontinuously from the 1st axial part 26 to the edge part 28. FIG.

  FIG. 8 is a diagram showing the back surface 34 of the X scanner 20 in the second modification. In this example, the plurality of holes 32 increase in density in the Z direction from the first shaft portion 26 to the end portion 28. Specifically, although there is one hole 32 at a position corresponding to the first shaft portion 26, the number of the holes 32 gradually increases to three, five, and seven as the end portion 28 is approached. Further, the three holes 32 arranged in the Z direction are separated by an equal distance in the Z direction. The same applies to five holes and seven holes arranged in the Z direction. This is different from the first embodiment. The other points are the same as in the first embodiment.

  FIG. 9 is a diagram showing the back surface 34 of the X scanner 20 in the third modification. In the present example, the plurality of holes 32 are not provided in the first shaft portion 26. This is different from the first embodiment. The other points are the same as in the first embodiment. With the configuration of this example, the strength of the first shaft portion 26 can be further improved.

  FIG. 10 is a diagram showing the back surface 34 of the X scanner 20 in the second embodiment. In the first reflecting portion 21 in this example, the opening area of the hole 32 differs depending on the position in the Z direction in the vicinity of the end portion 28. The plurality of holes 32 of the present example include a first hole 32-1 provided at a position corresponding to the drive unit 52, a second hole 32-2 provided at a position corresponding to the detection unit 72, and a shield. And a third hole 32-3 provided at a position corresponding to the portion 62.

  In this example, the hole 32 provided at a position corresponding to the drive unit 52 is a region that overlaps the first reflection unit 21 when the tip of the drive unit 52 provided with the comb teeth is extended in the X direction. Means the hole 32 closest to the end 28. Similarly, the holes 32 provided at the positions corresponding to the shield part 62 and the detection part 72 also have the first end when the tip part provided with the comb teeth of the shield part 62 and the detection part 72 is extended in the X direction. It means the hole 32 closest to the end portion 28 in the region overlapping with the reflecting portion 21.

  Since the driving unit 52 rotates and vibrates the first reflecting unit 21, the comb tooth at the position corresponding to the driving unit 52 needs the most mechanical strength. Since the detection unit 72 detects the rotation angle of the first reflection unit 21, the comb teeth provided at the position corresponding to the detection unit 72 require mechanical strength next to the comb teeth of the drive unit 52. On the other hand, since the shield part 62 only needs to exhibit a function of preventing the capacitive coupling between the drive part 52 and the detection part 72, the mechanical strength of the comb teeth provided at the position corresponding to the shield part 62 is 52 and the shield part 62 may be lower.

  Therefore, in this example, the volume of the first hole 32-1 is made smaller than the volume of the second hole 32-2, and the volume of the second hole 32-2 is made larger than the volume of the third hole 32-3. Make it smaller. Specifically, the first hole 32-1, the second hole 32-2, and the third hole 32-3 of the present example have the same depth 33. However, the opening area of the first hole 32-1 is smaller than the opening area of the second hole 32-2, and the opening area of the second hole 32-2 is the opening area of the third hole 32-3. Less than. Thereby, it is possible to reduce the moment of inertia as in the first embodiment, while preventing damage to the drive unit 52, the detection unit 72, and the shield unit 62 in descending order of priority.

  In this example as well as the first example, the plurality of holes 32 are arranged symmetrically with respect to the first shaft portion 26. In this example, the holes 32 other than the hole 32 closest to the end portion 28 have the same volume as the hole 32-2. In addition, each of the plurality of holes 32 has a cylindrical shape having a circular opening. Also in this example, the number of the plurality of holes 32 increases from the first shaft portion 26 to the end portion 28.

  FIG. 11 is a diagram illustrating (A) the back surface 34 of the X scanner 20 and (B) a CC ′ cross section in the third embodiment. The recess 30 in this example does not have a plurality of holes 32. The volume of the concave portion in this example continuously increases from the first shaft portion 26 to the end portion 28.

  As shown to (A), the recessed part 30 of this example has a triangular shape from which the width | variety of a Z direction becomes large from the 1st axial part 26 to the edge part 28 in a XZ plane. Moreover, as shown in (B), the recessed part 30 of this example has a triangular pyramid shape having a vertex on the first reflecting surface 24 side. The cone may have a shape that occurs when a triangular opening having a larger area than the hole 32 is etched. However, the etching conditions are controlled so that the apex of the cone does not penetrate the first reflecting surface 24.

  Also in this example, the moment of inertia around the first shaft portion 26 can be more effectively reduced while maintaining the mechanical strength of the first shaft portion 26. In addition, power consumption required for driving the first reflecting portion 21 can be reduced. The concave portion 30 of this example has a triangular shape on the back surface 34. However, if the volume continuously increases from the first shaft portion 26 to the end portion 28, a trapezoidal shape and other polygonal shapes may be used.

  FIG. 12 is a top view of the biaxial scanner 80 in the fourth embodiment. The biaxial scanner 80 of this example includes a first reflecting portion 81, a first beam portion 82, a suspension frame portion 90, and a second beam portion 92. The first reflecting portion 81 has a reflecting surface 84. The first reflecting portion 81 passes through the first beam portion 82 and extends in the Z direction, and the first shaft portion 86 passes through the second beam portion 92 and extends in the X direction. Part 96. As described above, the first shaft portion 86 and the second shaft portion 96 may have the same thickness as the thickness of the active layer of the SOI substrate 104.

  The first reflecting portion 81 is connected to one end 83 of the first beam portion 82 and can rotate around the first beam portion 82 as a rotation axis. The second beam portion 92 extends in the X direction. One end 93 of the second beam portion 92 is connected to the suspension frame portion 90. The hanging frame portion 90 is connected to the other end 85 of the first beam portion 82. The suspension frame portion 90 rotates around the second beam portion 92 as a rotation axis by electrostatic force between the comb teeth provided at the end portion in the Z direction and the comb teeth meshing with the comb teeth. The first reflecting portion 81 can rotate and vibrate with the first beam portion 82 and the second beam portion 92 as the rotation axes.

  FIG. 13 is a view showing the back surface 94 of the biaxial scanner 80. The first reflecting portion 81 has a back surface 94 located on the opposite side of the reflecting surface 84 and a concave portion 30 from which the rear surface portion is selectively removed. The recess 30 of this example also has a plurality of holes 95. Each of the plurality of holes 32 may have a cylindrical shape having a circular opening. The plurality of holes 95 in this example are provided at symmetrical positions with respect to the first shaft portion 86 and the second shaft portion 96.

  In this example, the end portion 88 is the end portion of the first reflecting portion 81 farthest from the first shaft portion 86, and the end portion 89 is the first reflecting portion 81 farthest from the second shaft portion 96. Is the end of The plurality of holes 95 in this example have the same depth. However, the hole 95-3 closest to the end portion 88 and the end portion 89 has the largest opening area, and the hole 95-1 located at the intersection of the first shaft portion 86 and the second shaft portion 96 has the largest opening area. small. The hole 95-2 located between the hole 95-1 and the hole 95-3 has an opening area larger than the hole 95-1 and smaller than the hole 95-3. Therefore, the volume of the recess 30 in this example increases from the first shaft portion 86 to the end portion 88 and increases from the second shaft portion 96 to the end portion 89.

  In this example, the moment of inertia of the first reflecting portion 81 can be reduced while maintaining the mechanical strength of the shaft portion in the X direction in addition to the Z direction. In addition, since the moment of inertia can be effectively reduced, the power consumption required for driving the first reflecting portion 81 can be reduced. The first modified example in FIG. 7, the second modified example in FIG. 8, the third modified example in FIG. 9, the second embodiment in FIG. 10, and the third embodiment in FIG. 11 may be applied to this example. .

  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.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Even if the operation flow in the claims, the description, and the drawings is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

10 .. Tube, 12 .. Flange, 14 .. Lens holder, 16 .. Objective lens, 17 .. Collimate lens, 18 .. Lens holder, 19 .. Optical fiber, 20. 1 reflecting part, 22 .. first beam part, 23 .. one end, 24 .. reflecting surface, 26 .. first shaft part, 28 .. end part, 30 .. recessed part, 32. 33 .. Depth, 34 .. Back, 42 .. Fixed part, 52 .. Drive part, 62 .. Shield part, 72 .. Detection part, 80 .. Biaxial scanner, 81. , 82 .. First beam portion, 83 .. One end, 84 .. Reflecting surface, 85 .. Other end, 86 .. First shaft portion, 88 .. End portion, 89 .. End portion, 90. .Suspension frame part 92 ..Second beam part 93 ..One end 94 ..Back surface 95 ..Hole 96 .. Second shaft part 100 ..Scanner unit 102 .. Fixed mirror, 104 .. SOI substrate, 106 .. Wiring substrate, 108 .. IC chip, 110 .. Charge-voltage converter circuit, 112 .. Amplifier, 113 .. Non-inverting input terminal, 114. Terminal 115, Output terminal 116, Resistor 118, Capacitor 119, Control unit 120, Y scanner 121, Second reflector 122, Second beam 123, 123 .., one end, 124..second reflecting surface, 126..second shaft portion, 128..end portion, 142..fixed portion, 152..drive portion, 162..shield portion, 172..detector 200 .. Optical scanning device, 210... Non-scanning optical device, 220.. Forceps port, 230 .. Light, 240. 314..Fluorescence, 320 .. Ichroic mirror, 330... Light detection section, 340... AD conversion section, 350... Image processing section, 360... Display section, 400 .. endoscope system, 500.

Claims (12)

A first beam portion extending in a first direction;
In an optical scanning device comprising: a first reflecting portion connected to one end of the first beam portion and capable of rotating about the first beam portion as a rotation axis;
The first reflecting portion is
A reflective surface that reflects light;
A back surface located on the opposite side of the reflective surface;
A recess having a part of the back surface selectively removed;
From the first shaft portion of the first reflecting portion extending in the first direction through the first beam portion, to the end portion of the first reflecting portion farthest from the first shaft portion. An optical scanning device in which the volume of the concave portion is increased. The recess has a plurality of holes having a predetermined depth;
The optical scanning device according to claim 1, wherein the number of the plurality of holes increases from the first shaft portion to the end portion of the first reflecting portion. The optical scanning device according to claim 2, wherein the plurality of holes are arranged symmetrically with respect to the first shaft portion. The optical scanning device according to claim 2, wherein the plurality of holes increase in density in the first direction from the first shaft portion to the end portion of the first reflecting portion. 4. The light according to claim 2, wherein each of the plurality of holes has an equal volume and is provided at a predetermined pitch in the first direction and a second direction orthogonal to the first direction. Scanning device. 6. The optical scanning device according to claim 2, wherein each of the plurality of holes is one of a cylinder and a prism. 7. The optical scanning device according to claim 2, wherein each of the plurality of holes does not penetrate to the reflection surface of the first reflection unit. The optical scanning device according to claim 2, wherein the plurality of holes are not provided in the first shaft portion. The plurality of holes are:
A first hole provided at a position corresponding to a driving unit for rotating and vibrating the first reflecting unit;
A second hole provided at a position corresponding to a detection unit for detecting a rotation angle of the first reflection unit;
A third hole provided at a position corresponding to a shield part that prevents capacitive coupling between the drive part and the detection part;
The volume of the first hole is smaller than the volume of the second hole,
The optical scanning device according to claim 2, wherein a volume of the second hole is smaller than a volume of the third hole. 2. The optical scanning device according to claim 1, wherein the volume of the concave portion continuously increases from the first shaft portion to the end portion of the first reflecting portion. A second beam portion extending in a second direction orthogonal to the first direction;
A suspension frame portion connected to the other end of the first beam portion and one end of the second beam portion and capable of rotating about the second beam portion as a rotation axis;
From the second shaft portion of the first reflecting portion that passes through the second beam portion and extends in the second direction to the end portion of the first reflecting portion that is parallel to the second direction, The optical scanning device according to claim 1, wherein the volume of the concave portion increases.   An endoscope equipped with the optical scanning device according to any one of claims 1 to 11.

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