JP2014164101A - Optical deflector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical deflector capable of suppressing the deterioration of a deflection angle of the optical deflector, and accurately detecting the deflection angle of the optical deflector.SOLUTION: An optical deflector A1 includes: a moving portion 9 for supporting a reflecting portion 1 having an optical reflection surface 1b formed by a metallic thin film; a supporting base body 11 for supporting the moving portion 9; and outside piezoelectric actuators 101 and 102 for rocking the moving portion 9 about a second shaft X2 by piezoelectric drive. The outside piezoelectric actuators 101 and 102 are equipped with a plurality of piezoelectric cantilevers 31-34 which support a driving piezoelectric body 61 and bent and deformed with the driving piezoelectric body 61. The plurality of piezoelectric cantilevers 31-34 are coupled at end portions so as to accumulate each bending deformation. The moving portion 9 is provided with detecting cantilevers 91 and 92 bent and deformed according to the rocking about the second shaft X2, and the detecting cantilevers 91 and 92 support a detecting piezoelectric body 62 bent and deformed with their bending deformation.

Description

  The present invention relates to an optical deflector that can swing a reflecting surface.

  2. Description of the Related Art Conventionally, an optical deflector including a mirror unit having a reflecting surface and a piezoelectric actuator that drives the mirror unit is known (Patent Document 1).

  In this optical deflector, the piezoelectric actuator includes a piezoelectric body to which a driving voltage is applied, and a support body that supports the piezoelectric body and bends and deforms together with the piezoelectric body.

JP 2008-40240 A

  In the optical deflector described in Patent Document 1, the deflection angle can be accurately controlled by detecting and feeding back the actual deflection angle. In order to detect the actual deflection angle, it is conceivable to dispose a driving piezoelectric member and a detecting piezoelectric member on the support. Accordingly, the piezoelectric body for detection is bent and deformed together with the support body as the driving piezoelectric body is driven, and a voltage corresponding to the bending deformation is output from the piezoelectric body for detection.

  However, when the driving piezoelectric member and the detection piezoelectric member are provided on the support, the driving piezoelectric member occupying on the support is less than when the detection piezoelectric member is not provided on the support. Therefore, the bending deformation of the support is reduced. For this reason, there exists a possibility that the deflection angle of an optical deflector may fall.

  Furthermore, since the ratio of the area of the detection piezoelectric material that occupies the piezoelectric cantilever is small, the voltage output from the detection piezoelectric material is also small. For this reason, it becomes difficult to discriminate between the detection voltage and the noise component output from the piezoelectric body for detection, and the detection accuracy of the deflection angle of the optical deflector may be lowered.

  The present invention has been made in view of the above points, and an object thereof is to provide an optical deflector that can suppress a decrease in the deflection angle of the optical deflector and can accurately detect the deflection angle of the optical deflector. To do.

  The present invention includes a mirror portion having a reflecting surface and a piezoelectric actuator that swings the mirror portion around a predetermined axis (X2) by piezoelectric driving, and the piezoelectric actuator is a driving piezoelectric device to which a driving voltage is applied. An optical deflector comprising a body and a support body that supports the driving piezoelectric body and bends and deforms together with the driving piezoelectric body, wherein the mirror section swings around the predetermined axis. A detection cantilever that bends and deforms in response to the swinging of the detection cantilever, and the detection cantilever supports a detection piezoelectric body that bends and deforms along with the bending deformation of the detection cantilever. To do.

  According to the present invention, when the mirror portion is swung around a predetermined axis by the piezoelectric actuator, the detection cantilever is bent and deformed according to the swing. Along with the bending deformation, the detection piezoelectric body supported by the detection cantilever is bent and deformed. Accordingly, a voltage signal (detection voltage) corresponding to the swing of the mirror portion is output from the detection piezoelectric body.

  Since the detection piezoelectric body is not provided on the piezoelectric cantilever, the area of the driving piezoelectric body on the piezoelectric cantilever does not decrease. Thereby, it is possible to suppress the bending deformation of the piezoelectric cantilever from being reduced, and consequently to suppress the decrease in the deflection angle of the optical deflector.

  Further, the detection piezoelectric body is arranged on a detection cantilever different from the piezoelectric cantilever supporting the drive piezoelectric body. For this reason, it becomes possible to adjust the size (area) of the detection piezoelectric body so that the detection voltage output from the detection piezoelectric body can be determined from the detection voltage and the noise component. The deflection angle of the optical deflector can be accurately detected.

  In the present invention, the detection cantilever is preferably formed such that its free end side is heavier than the base end side. Since the free end side is heavier than the base end side, the bending deformation of the detection cantilever corresponding to the swinging of the mirror portion can be increased. Thereby, the detection voltage with respect to the area of the piezoelectric substance for a detection becomes large, and the deflection angle of an optical deflector can be detected accurately.

  In the present invention, the detection cantilever is preferably formed such that its longitudinal direction is perpendicular to the axial direction of the predetermined axis. Accordingly, the detection cantilever is easily bent and deformed according to the swinging of the mirror portion. Therefore, the deflection angle of the optical deflector can be detected with high accuracy.

  In the present invention, it is preferable that the detection cantilever is formed such that a base end thereof is positioned on a free end side of the detection cantilever with respect to the predetermined axis. As a result, the detection cantilever is formed so as not to include a predetermined axis that is the central axis of oscillation. Accordingly, the detection cantilever is easily bent and deformed according to the swing of the mirror portion, and the deflection angle of the optical deflector can be detected with high accuracy.

  In the present invention, the piezoelectric actuator includes a plurality of piezoelectric cantilevers each having the driving piezoelectric body and the support, and the plurality of piezoelectric cantilevers have end portions connected so as to accumulate respective bending deformations. Preferably it is. Thereby, since the bending deformation of the plurality of piezoelectric cantilevers is accumulated, the deflection angle of the optical deflector can be increased.

  In the present invention, the mirror unit includes a reflecting unit having the reflecting surface, another piezoelectric actuator that swings the reflecting unit around an axis (X1) different from the predetermined axis by piezoelectric driving, A support portion that supports the reflection portion via another piezoelectric actuator, and the another piezoelectric actuator supports another drive piezoelectric body to which a drive voltage is applied, and the other drive piezoelectric body. A plurality of other piezoelectric cantilevers that bend and deform together with the other driving piezoelectric body, and the plurality of other piezoelectric cantilevers are connected at their ends so as to accumulate each bending deformation, and are connected to the reflecting portion. Is provided with another detection cantilever that bends and deforms in response to the swinging of the reflecting portion about the other axis, and the other detection cantilever is provided with the other detection cantilever. With bending deformation It is preferred to support the different sensing piezoelectric member to tune deformed.

  Thus, when the mirror portion is swung around another axis by another piezoelectric actuator, another detection cantilever is bent and deformed in accordance with the swing. Along with this bending deformation, another detection piezoelectric member supported by the other detection cantilever is bent and deformed. Accordingly, a voltage signal (detection voltage) corresponding to the swing of the mirror portion is output from another detection piezoelectric body.

  Since another detection piezoelectric body is not provided on another piezoelectric cantilever, the area of another driving piezoelectric body occupying on another piezoelectric cantilever is not reduced. Thereby, it is possible to suppress the bending deformation of another piezoelectric cantilever from being reduced, and consequently to suppress a decrease in the deflection angle around another axis of the optical deflector.

  Further, another detection piezoelectric body is arranged on another detection cantilever different from another piezoelectric cantilever supporting another drive piezoelectric body. For this reason, the size (area) of the other detection piezoelectric member is adjusted so that the detection voltage output from the other detection piezoelectric member is large enough to distinguish the detection voltage and the noise component. Therefore, the deflection angle around another axis of the optical deflector can be accurately detected.

The perspective view which shows the structure of the optical deflector of 1st Embodiment of this invention. The enlarged view of the detection cantilever of the optical deflector of FIG. Sectional drawing which shows typically structures, such as a piezoelectric cantilever with which the optical deflector of FIG. 1 is equipped. The perspective view which shows the structure of the optical deflector of 2nd Embodiment of this invention.

[First Embodiment]
The optical deflector according to the first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the optical deflector A1 of the present embodiment includes a reflection unit 1 having a reflection surface 1b that reflects incident light, a movable unit 9 on which the reflection unit 1 is mounted, and the reflection unit 1. Piezoelectric actuators (hereinafter referred to as “inner piezoelectric actuators”) 81 and 82 for causing the movable portion 9 to swing around the first axis X 1, and the reflecting portion 1 and the movable portion 9 with respect to the support base 11. Piezoelectric actuator (hereinafter referred to as “axis perpendicular to the first axis X1; however, the first axis X1 and the second axis X2 do not have to be exactly perpendicular to each other”). 101 and 102 (referred to as “outer piezoelectric actuators”).

  The reflecting portion 1 includes a disk-shaped reflecting portion base 1a and a reflecting surface 1b formed of a metal thin film on the reflecting portion base 1a, and extends outward from both ends in the diameter direction of the reflecting portion base 1a. It is connected to the movable part 9 via a pair of torsion bars 2a, 2b provided.

  Specifically, the movable portion 9 is formed in a rectangular frame shape and is provided so as to surround the periphery of the reflecting portion 1. And the front-end | tip part of each torsion bar 2a, 2b extended from the reflection part base | substrate 1a is connected with the inner peripheral part of the movable part 9. As shown in FIG. As a result, the reflecting portion 1 is connected to the movable portion 9 and can swing around the first axis X1 that is the axis of the torsion bars 2a and 2b by twisting the torsion bars 2a and 2b. Yes.

  In addition, when the movable portion 9 swings around the second axis X2 by the outer piezoelectric actuators 101 and 102, the movable cantilever 91 and 92 for detection are bent and deformed in response to the swing. Is provided. Specifically, the detection cantilevers 91 and 92 are formed so that the longitudinal direction thereof is orthogonal to the axial direction of the second axis X2. At this time, the detection cantilevers 91 and 92 are connected to the connecting portion where the outer piezoelectric actuators 101 and 102 and the movable portion 9 are connected in the direction parallel to the axis of the first axis X1. The base ends 91a and 92a are provided, and the free ends 91b and 92b of the detection cantilevers 91 and 92 are provided on the side opposite to the connection portion with respect to the base ends 91a and 92a.

  Further, the detection cantilevers 91 and 92 have their base ends 91a and 92a positioned closer to the free ends 91b and 92b of the detection cantilevers 91 and 92 than the second axis X2 in the axial direction of the first axis X1. It is formed as follows.

  In the present embodiment, the second axis X2 is located at the center of the movable portion 9 in the axial direction of the first axis X1. For this reason, the base ends 91 a and 92 a of the detection cantilevers 91 and 92 are formed so as to be located slightly on the free ends 91 b and 92 b side from the center of the movable portion 9.

  The detection cantilevers 91 and 92 are formed such that the free ends 91b and 92b are heavier than the base ends 91a and 92a. Specifically, the thick portions 91c and 92c are formed so that the thickness on the free ends 91b and 92b side is thicker than that on the base ends 91a and 92a side (see FIGS. 2 and 3).

  The inner piezoelectric actuators 81 and 82 that swing the reflecting portion 1 with respect to the movable portion 9 are each formed in a semicircular arc shape, and are disposed with a gap so as to surround the reflecting portion 1. The inner piezoelectric actuators 81 and 82 are arranged such that one end of each is opposed to sandwich one torsion bar 2a, and the other end of each is opposed to sandwich the other torsion bar 2b. Yes. Each of the inner piezoelectric actuators 81 and 82 is configured by a piezoelectric cantilever configured to bend and deform by piezoelectric driving. As a result, the inner piezoelectric actuators 81 and 82 are bent and deformed by the piezoelectric drive, whereby the torsion bars 2a and 2b are twisted.

  The support base 11 is formed in a rectangular frame shape and is provided so as to surround the periphery of the movable portion 9. A pair of outer piezoelectric actuators 101 and 102 that swing the reflecting portion 1 and the movable portion 9 with respect to the support base 11 are provided between the inner peripheral portion of the support base 11 and the outer peripheral portion of the movable portion 9. The movable portion 9 is supported by the support base 11 via the outer piezoelectric actuators 101 and 102 via the outer piezoelectric actuators 101 and 102.

  Each of the outer piezoelectric actuators 101 and 102 is configured by connecting a plurality of (four in the illustrated example) piezoelectric cantilevers 31 to 34 each configured to bend and deform by piezoelectric driving. In this case, the plurality of piezoelectric cantilevers 31 to 34 constituting the respective outer piezoelectric actuators 101 and 102 are arranged in a direction perpendicular to the second axis X2 between the inner peripheral portion of the support base 11 and the outer peripheral portion of the movable portion 9. The piezoelectric cantilevers 31 to 34 are connected so as to be folded with respect to the adjacent piezoelectric cantilevers while extending and arranged so as to be aligned in the direction of the second axis X2. Therefore, each outer piezoelectric actuator 101, 102 extends so as to meander with the direction orthogonal to the second axis X2 as the amplitude direction.

  One end of each outer piezoelectric actuator 101, 102 (the base end of the piezoelectric cantilever 34 closest to the support base 11) is connected to the inner periphery of the support base 11, and the other end (most movable part 9). A distal end portion of the piezoelectric cantilever 31 on the side is connected to the outer peripheral portion of the movable portion 9.

  As a result, the movable portion 9 is supported by the support base 11 via the outer piezoelectric actuators 101 and 102, and the support base 11 is deformed by bending deformation of the piezoelectric cantilevers 31 to 34 constituting the outer piezoelectric actuators 101 and 102. Thus, it can swing around the second axis X2.

  In the following description, the piezoelectric cantilevers 31 to 34 constituting the outer piezoelectric actuators 101 and 102 are respectively defined as the first, second, third, and fourth piezoelectric cantilevers in order from the movable portion 9 side. The piezoelectric cantilevers 31 and 33 may be referred to as odd-numbered piezoelectric cantilevers, and the piezoelectric cantilevers 32 and 34 may be referred to as even-numbered piezoelectric cantilevers.

  In the illustrated optical deflector A1, the number of the piezoelectric cantilevers 31 to 34 constituting each of the outer piezoelectric actuators 101 and 102 is four. However, the outer piezoelectric actuators 101 and 102 are composed of more piezoelectric cantilevers. Of course, you may do it.

  Each of the inner piezoelectric actuators 81 and 82, each of the piezoelectric cantilevers 31 to 34 constituting the outer piezoelectric actuators 101 and 102, and each of the detection cantilevers 91 and 92 is shown in a schematic sectional view in FIG. Further, the piezoelectric cantilever has a structure in which a layer of a lower electrode 5, a piezoelectric body 6, and an upper electrode 7 is laminated on a layer of a support body 4 as a strain generating body (cantilever body).

  Among these, each of the inner piezoelectric actuators 81 and 82 and each of the piezoelectric cantilevers 31 to 34 constituting the outer piezoelectric actuators 101 and 102 apply a driving voltage to the piezoelectric body 6 between the lower electrode 5 and the upper electrode 7. By doing so, the support body 4 is bent and deformed together with the piezoelectric body 6. Further, the detection cantilevers 91 and 92 are configured such that a voltage corresponding to the bending deformation is output from the piezoelectric body 6 when the support body 4 and the piezoelectric body 6 are bent and deformed.

  In the following description, the piezoelectric body 6 disposed in the piezoelectric cantilevers 31 to 34 is referred to as a driving piezoelectric body 61, and the piezoelectric body 6 disposed in the detection cantilevers 91 and 92 is referred to as a detection piezoelectric body 62.

  The connecting portions of the adjacent piezoelectric cantilevers among the piezoelectric cantilevers 31 to 34 of the outer piezoelectric actuators 101 and 102 are portions where the supporting bodies 4 of the adjacent piezoelectric cantilevers are integrally connected, The layers of the piezoelectric body 6 and the upper electrode 7 are not provided.

  On the support base 11, ten electrode pads 121 to 126, 131, 132, 141, 142 are provided.

  Of these electrode pads 121 to 126, 131, 132, 141, 142, two electrode pads 131, 132 are electrode pads that serve as reference potential points (hereinafter referred to as “lower electrode pads”).

  In the following description, the eight electrode pads 121 to 126, 141, and 142 other than the lower electrode pads 131 and 132 may be referred to as upper electrode pads.

  The eight upper electrode pads 121 to 126, 141, and 142 are six upper electrode pads (hereinafter referred to as “drive electrode pads”) 121 to piezoelectrically drive the inner piezoelectric actuators 81 and 82 and the outer piezoelectric actuators 101 and 102. 126 and two upper electrode pads (hereinafter referred to as “detection electrode pads”) 141 and 142 for acquiring a voltage output from the detection cantilevers 91 and 92 according to the bending deformation of the detection cantilevers 91 and 92. It consists of.

  The drive electrode pad 121 is an upper electrode pad for applying a drive voltage between the upper electrode 7 and the lower electrode 5 of the inner piezoelectric actuator 81. The drive electrode pad 122 is an upper electrode pad for applying a drive voltage between the upper electrode 7 and the lower electrode 5 of the inner piezoelectric actuator 82.

  The drive electrode pad 123 is an upper electrode pad for applying a drive voltage between the upper electrode 7 and the lower electrode 5 of the odd-numbered piezoelectric cantilevers 31 and 33 of the outer piezoelectric actuator 101. The drive electrode pad 124 is an upper electrode pad for applying a drive voltage between the upper electrode 7 and the lower electrode 5 of the even-numbered piezoelectric cantilevers 32 and 34 of the outer piezoelectric actuator 101.

  The drive electrode pad 125 is an upper electrode pad for applying a drive voltage between the upper electrode 7 and the lower electrode 5 of the odd-numbered piezoelectric cantilevers 31 and 33 of the outer piezoelectric actuator 102. The drive electrode pad 126 is an upper electrode pad for applying a drive voltage between the upper electrode 7 and the lower electrode 5 of the even-numbered piezoelectric cantilevers 32 and 34 of the outer piezoelectric actuator 102.

  The detection electrode pad 141 is an upper electrode pad for acquiring a voltage output from the piezoelectric body 6 (that is, the detection piezoelectric body 62) of the detection cantilever 91. The detection electrode pad 142 is an upper electrode pad for acquiring a voltage output from the piezoelectric body 6 (that is, the detection piezoelectric body 62) of the detection cantilever 92.

  The lower electrode pad 131 is a lower electrode pad common to the upper electrode pads 121, 123, 124, and 141. The lower electrode pad 132 is a common lower electrode pad for the upper electrode pads 122, 125, 126, and 142.

  The lower electrode 5 and the lower electrode pads 131 and 132 are a metal thin film (in this embodiment, two metal thin films; hereinafter referred to as a lower electrode layer) on a semiconductor substrate (for example, a silicon substrate) constituting the support 4. ) Is processed by using a semiconductor planar process. As a material of the metal thin film, for example, titanium (Ti) is used for the first layer (lower layer), and platinum (Pt) is used for the second layer (upper layer).

  The lower electrodes 5 of the inner piezoelectric actuators 81 and 82 (piezoelectric cantilevers) are formed on almost the entire surface of the inner piezoelectric actuators 81 and 82 on the support 4. The lower electrodes 5 of the piezoelectric cantilevers 31 to 34 of the outer piezoelectric actuators 101 and 102 are respectively on the support body 4 (the whole of the linear portion (the portion where each piezoelectric cantilever 31 to 34 extends) and the connecting portion are combined). It is formed on almost the entire surface. The lower electrodes 5 of the detection cantilevers 91 and 92 are formed on substantially the entire surface of the support 4.

  The lower electrode pads 131 and 132 are respectively connected to the lower electrode 5 of the inner piezoelectric actuators 81 and 82 and the outer piezoelectric actuators 101 and 102 via lower electrode layers formed on the support base 11 and the movable portion 9. Conduction is conducted to the lower electrode 5 and the lower electrodes 5 of the detection cantilevers 91 and 92.

  The inner piezoelectric actuators 81 and 82 (piezoelectric cantilevers), the piezoelectric cantilevers 31 to 34 of the outer piezoelectric actuators 101 and 102, and the piezoelectric bodies 6 of the detection cantilevers 91 and 92 are formed using a semiconductor planar process. By forming a single piezoelectric film (hereinafter sometimes referred to as a piezoelectric layer) on the electrode layer, the piezoelectric films are formed separately on the lower electrode 5 of each piezoelectric cantilever. As a material of this piezoelectric film, for example, lead zirconate titanate (PZT) which is a piezoelectric material is used.

  In this case, the piezoelectric body 6 of each of the inner piezoelectric actuators 81 and 82 is formed on almost the entire surface of the lower electrode 5 for each of the inner piezoelectric actuators 81 and 82. In addition, the piezoelectric body 6 (specifically, the driving piezoelectric body 61) of each of the outer piezoelectric actuators 101 and 102 is disposed on almost the entire surface of the lower electrode 5 in the extending portion (straight portion) of each piezoelectric cantilever 31-34. Is formed. The piezoelectric bodies 6 (specifically, the detection piezoelectric bodies 62) of the detection cantilevers 91 and 92 are formed on substantially the entire surface of the lower electrode 5 of the detection cantilevers 91 and 92.

  Each upper electrode 7, upper electrode pads 121 to 126, 141, and 142, and upper electrode wiring (not shown) that conducts them are formed using a metal thin film (this embodiment) on the piezoelectric layer using a semiconductor planar process. Then, a single metal thin film (hereinafter sometimes referred to as an upper electrode layer) is formed by shape processing. For example, platinum (Pt) or gold (Au) is used as the material of the metal thin film.

  In this case, the upper electrodes 7 of the inner piezoelectric actuators 81 and 82 are formed on almost the entire surface of the piezoelectric body 6 for each piezoelectric cantilever. The upper electrodes 7 of the outer piezoelectric actuators 101 and 102 are formed on almost the entire surface of the piezoelectric body 6 for each piezoelectric cantilever. The upper electrodes 7 of the detection cantilevers 91 and 92 are formed on almost the entire surface of the piezoelectric can 6 of the detection cantilevers 91 and 92.

  The drive electrode pads 121 and 122 are electrically connected to the upper electrode 7 of the inner piezoelectric actuator 81 and the upper electrode 7 of the inner piezoelectric actuator 82 via upper electrode wiring (not shown), respectively.

  Further, the drive electrode pads 123 to 126 are respectively the upper electrodes 7 of the odd-numbered piezoelectric cantilevers 31 and 33 of the outer piezoelectric actuator 101, the upper electrodes 7 of the even-numbered piezoelectric cantilevers 32 and 34 of the outer piezoelectric actuator 101, and the outer piezoelectric. The upper electrode 7 of the odd-numbered piezoelectric cantilevers 31 and 33 of the actuator 102 and the upper electrode 7 of the even-numbered piezoelectric cantilevers 32 and 34 of the outer piezoelectric actuator 102 are electrically connected to each other via an upper electrode wiring (not shown). Is done.

  The detection electrode pads 141 and 142 are electrically connected to the upper electrode 7 of the detection cantilever 91 and the upper electrode 7 of the detection cantilever 92 via an upper electrode wiring (not shown).

  The reflecting surface 1b of the reflecting portion 1 is formed by processing a metal thin film (one metal thin film in this embodiment) on the reflecting portion base 1a using a semiconductor planar process. As the material of the metal thin film, for example, gold (Au), platinum (Pt), silver (Ag), aluminum (Al), or the like is used.

  Further, the reflecting portion base 1a, the torsion bars 2a and 2b, the support 4, the movable portion 9, and the supporting base 11 are formed by processing a semiconductor substrate (silicon substrate) composed of a plurality of layers. It is integrally formed. As a technique for processing a shape of a semiconductor substrate, a semiconductor planar process and a MEMS process using a photolithography technique or a dry etching technique are used.

  Further, the thick portions 91c and 92c provided on the detection cantilevers 91 and 92 of the movable portion 9 are surfaces opposite to the surfaces on which the lower electrodes 5 and the like of the support 4 of the detection cantilevers 91 and 92 are provided. From, it protrudes toward the normal direction of the surface (refer to Drawing 2 and Drawing 3). The thick portions 91c and 92c are formed when the silicon substrate is processed.

  Further, the optical deflector A1 is connected to a control circuit (not shown) that controls the swinging (deflection and scanning) of the reflection unit 1. The control circuit is an electronic circuit unit including a CPU, a processor, a storage device, and the like. The control circuit controls drive voltages applied to the inner piezoelectric actuators 81 and 82 and the outer piezoelectric actuators 101 and 102.

  The control circuit detects the voltage output from the piezoelectric body 6 (that is, the detection piezoelectric body 62) of the detection cantilevers 91 and 92. Based on the detected voltage, the control circuit so that the swing of the movable portion 9 with respect to the support base 11 becomes a target swing (that is, the deflection angle of the reflecting portion 1 around the second axis X2 is The drive voltage applied to the outer piezoelectric actuators 101 and 102 is feedback controlled so that the target deflection angle is obtained.

  In the present embodiment, the reflecting portion 1, the torsion bars 2a and 2b, the inner piezoelectric actuators 81 and 82, and the movable portion 9 constitute a mirror portion in the present invention. The outer piezoelectric actuators 101 and 102 correspond to “piezoelectric actuators” in the present invention. The support 4 of each of the piezoelectric cantilevers 31 to 34 of the outer piezoelectric actuators 101 and 102 corresponds to the “support” in the present invention. The second axis X2 corresponds to the “predetermined axis” in the present invention.

  Next, the operation of the optical deflector A1 of this embodiment will be described.

  The optical deflector A1 is provided in an image display apparatus such as an electrophotographic image forming apparatus or a scanning display, for example, and deflects and scans light incident on the reflection unit 1 with respect to an image projection surface or the like.

  In this case, the inner piezoelectric actuators 81 and 82 are piezoelectrically driven to swing the reflecting portion 1 around the first axis X1, and the outer piezoelectric actuators 101 and 102 are piezoelectrically driven to reflect the reflecting portion 1 (or moveable). Part 9) is swung around the second axis X2. The swinging around the first axis X1 and the swinging around the second axis X2 of the reflecting unit 1 are, for example, swinging for horizontal deflection and scanning, vertical deflection and scanning, respectively.

  The reflection unit 1 is swung around the first axis X1 as follows. In other words, the control circuit applies a first drive voltage between the upper electrode 7 and the lower electrode 5 of the inner piezoelectric actuator 81 and performs a second drive between the upper electrode 7 and the lower electrode 5 of the inner piezoelectric actuator 82. Apply voltage. In this case, the first drive voltage and the second drive voltage are alternating voltages (for example, sine waveforms) having a predetermined frequency that are opposite in phase or shifted in phase.

  As a result, the inner piezoelectric actuators 81 and 82 are piezoelectrically driven so as to bend and deform in opposite directions. These bending deformations cause torsional deformation of the torsion bars 2a and 2b. As a result, the reflecting portion 1 swings around the first axis X1. As a result, light deflection and scanning around the first axis X1 are performed.

  In the present embodiment, a voltage signal having a frequency near the mechanical resonance frequency of the reflector 1 including the inner piezoelectric actuators 81 and 82 is applied to the inner piezoelectric actuators 81 and 82 for resonance driving.

  The reflection unit 1 (or the movable unit 9) swings around the second axis X2 as follows. The control circuit outputs a third drive voltage for piezoelectrically driving the even-numbered piezoelectric cantilevers 32 and 34 of each of the outer piezoelectric actuators 101 and 102, and also outputs the odd-numbered piezoelectric cantilevers of each of the outer piezoelectric actuators 101 and 102. A fourth drive voltage for piezoelectrically driving 31 and 33 is output. Here, the fourth drive voltage is a voltage signal having a waveform having an opposite phase to the waveform of the third drive voltage.

  At this time, the control circuit applies a third drive voltage between the lower electrode 5 and the upper electrode 7 of each of the even-numbered piezoelectric cantilevers 32 and 34 of each of the outer piezoelectric actuators 101 and 102, thereby The piezoelectric cantilevers 32 and 34 are bent and deformed by piezoelectric driving. At the same time, the control circuit applies a fourth drive voltage between the lower electrode 5 and the upper electrode 7 of each of the odd-numbered piezoelectric cantilevers 31 and 33 of each of the outer piezoelectric actuators 101 and 102, thereby The cantilevers 31 and 33 are piezoelectrically driven to bend and deform.

  As a result, the distal end portion of the piezoelectric cantilever 34 (connecting portion with the movable portion 9) and the distal end portion of the piezoelectric cantilever 32 (connecting portion with the piezoelectric cantilever 33) are located at the base end portion of each piezoelectric cantilever 32, 34. The even-numbered piezoelectric cantilevers 32 and 34 are bent and deformed so as to be displaced in the same direction. The distal end portion of the piezoelectric cantilever 33 (connection portion with the piezoelectric cantilever 34) and the distal end portion of the piezoelectric cantilever 31 (connection portion with the piezoelectric cantilever 32) are relative to the base end portions of the piezoelectric cantilevers 31 and 33, respectively. The odd-numbered piezoelectric cantilevers 31 and 33 are bent and deformed so as to be displaced in the direction opposite to that of the piezoelectric cantilevers 32 and 34. Thereby, in the outer piezoelectric actuators 101 and 102, an angular displacement having a magnitude obtained by accumulating the magnitudes of the bending deformations of the piezoelectric cantilevers 31 to 34 is generated.

  By the operation of the outer piezoelectric actuators 101 and 102 as described above, the reflecting portion 1 swings around the second axis X2. Specifically, the deflection angle (swing amount) of the reflecting portion 1 changes in a waveform that substantially follows the waveforms of the third drive voltage and the fourth drive voltage.

  At this time, the outer piezoelectric actuators 101 and 102 are driven to resonate by applying a voltage signal having a frequency near the mechanical resonance frequency of the movable portion 9 including the outer piezoelectric actuators 101 and 102 as a drive voltage, thereby increasing the driving voltage. Optical scanning can be performed at a deflection angle.

  Further, since the outer piezoelectric actuators 101 and 102 are configured to accumulate the magnitude of the bending deformation of each piezoelectric cantilever 31 to 34, the voltage of the non-resonant frequency that is not the mechanical resonant frequency of the optical deflector A1. Even when a signal is applied, a deflection angle capable of optical scanning can be obtained sufficiently.

  Further, when the movable part 9 is swung around the second axis X2, it is not necessary to apply a voltage signal having periodicity as described above, and a DC voltage signal may be applied. In this case, the magnitude of bending deformation generated in the piezoelectric cantilevers 31 to 34 changes linearly according to the magnitude of the DC voltage. Therefore, for example, unlike the case where the piezoelectric cantilever is driven by resonance by applying a voltage signal having periodicity, an arbitrary output can be obtained from the outer piezoelectric actuators 101 and 102 by controlling the magnitude of the DC voltage.

  Thus, in the optical deflector A1, when swinging around the second axis X2, the deflection angle can be controlled linearly in accordance with the magnitude of the DC voltage applied as the drive voltage. An arbitrary deflection angle can be obtained at a speed of.

  In the optical deflector A1 of the present embodiment, the frequency of the first drive voltage and the second drive voltage applied when the reflecting unit 1 is swung around the first axis X1 is 30 [kHz]. The frequency of the third drive voltage and the fourth drive voltage applied when the reflecting portion 1 (or the movable portion 9) is swung around the second axis X2 is 60 [Hz].

  As described above, when the reflecting portion 1 (or the movable portion 9) is swung around the second axis X2 by the outer piezoelectric actuators 101 and 102, the detection cantilevers 91 and 92 bend according to the swing. Deform. With this bending deformation, the piezoelectric body 6 (that is, the detection piezoelectric body 62) of the detection cantilevers 91 and 92 is bent and deformed, and the detection cantilevers 91 and 92 vibrate in the direction indicated by the arrow in FIG. To do. Accordingly, a voltage signal (detection voltage) corresponding to the swing of the reflecting portion 1 (or the movable portion 9) is output from the detecting piezoelectric body 62 of the detecting cantilevers 91 and 92.

  At this time, since the detecting piezoelectric body 62 is not provided in the outer piezoelectric actuators 101 and 102, the area of the piezoelectric body 6 (that is, the driving piezoelectric body 61) occupying on each of the piezoelectric cantilevers 31 to 34 does not decrease. . Thereby, it can suppress that the bending deformation of each piezoelectric cantilever 31-34 becomes small, and can suppress the fall of the deflection angle of optical deflector A1 by extension.

  Further, the detection piezoelectric body 62 is disposed on detection cantilevers 91 and 92 different from the piezoelectric cantilevers 31 to 34 that support the drive piezoelectric body 61. For this reason, the size (area) of the detection cantilevers 91 and 92 and the detection piezoelectric body 62 is set so that the detection voltage output from the detection piezoelectric body 62 can be distinguished from the detection voltage and the noise component. ) Can be adjusted, and the deflection angle of the optical deflector A1 can be accurately detected.

  The detection cantilevers 91 and 92 are formed such that the free ends 91b and 92b are thicker than the base ends 91a and 92a. Thereby, in the detection cantilevers 91 and 92, the free ends 91b and 92b are heavier than the base ends 91a and 92a. Since the detection cantilevers 91 and 92 move on the free ends 91b and 92b from the base ends 91a and 92a as base points, the bending deformation of the detection cantilevers 91 and 92 increases as the free ends 91b and 92b become heavier (that is, The bending deformation of the detection cantilevers 91 and 92 corresponding to the swing of the movable portion 9 is increased). As a result, the voltage output from the detection piezoelectric body 62 becomes larger than the area of the detection piezoelectric body 62, and the deflection angle of the optical deflector A1 can be detected with high accuracy.

  Further, the detection cantilevers 91 and 92 are formed such that the longitudinal direction thereof is orthogonal to the axial direction of the second axis X2. Thereby, the detection cantilevers 91 and 92 are easily bent and deformed in accordance with the swinging of the reflecting portion 1 (or the movable portion 9). Therefore, the voltage output from the detection piezoelectric body 62 is increased, and the deflection angle of the optical deflector A1 can be detected with high accuracy.

  Further, the detection cantilevers 91 and 92 are formed such that their base ends 91a and 92a are located closer to the free ends 91b and 92b of the detection cantilevers 91 and 92 than the second axis X2. In other words, the detection cantilevers 91 and 92 are formed so as not to include the second axis X2 that is the central axis of the swing of the reflecting portion 1 (or the movable portion 9). Accordingly, the detection cantilevers 91 and 92 are easily bent and deformed in accordance with the swing of the reflecting portion 1 (or the movable portion 9), and the deflection angle of the optical deflector A1 can be detected with high accuracy.

[Second Embodiment]
Next, the optical deflector A2 of the second embodiment will be described with reference to FIG. The optical deflector A2 of the present embodiment is the same as the optical deflector A1 of the first embodiment, the reflecting portion 1 (corresponding to 201 in the present embodiment), and inner piezoelectric actuators 81 and 82 (281 and 282 in the present embodiment). The structure of Hereinafter, the description of the optical deflector A2 of the present embodiment will be made of differences from the optical deflector A1 of the first embodiment.

  In the present embodiment, the reflecting portion 201 is a reflecting surface formed of a rectangular plate-shaped reflecting portion base 201a and a rectangular metal thin film formed as a light reflecting surface at the central portion on the reflecting portion base 201a. 201b.

  Then, when the reflecting portion base 201a swings around the first axis X1 by the inner piezoelectric actuators 281 and 282, the detecting cantilever 291 that bends and deforms in response to the swinging. , 292 are provided. Specifically, the detection cantilevers 291 and 292 are formed such that the longitudinal direction thereof is orthogonal to the axial direction of the first axis X1. At this time, the detection cantilevers 291 and 292 are connected to the bases of the detection cantilevers 291 and 292 on the connecting portion side where the inner piezoelectric actuators 281 and 282 are connected to the reflecting portion base 201a in the axial direction of the second axis X2. Ends 291a and 292a are provided, and free ends 291b and 292b of the detection cantilevers 291 and 292 are provided on the side opposite to the connecting portion with respect to the base ends 291a and 292a.

  In addition, the detection cantilevers 291 and 292 have base ends 291a and 292a that are positioned closer to the free ends 291b and 292b of the detection cantilevers 291 and 292 than the first axis X1 in the axial direction of the second axis X2. It is formed as follows.

  In the present embodiment, the first axis X1 is located at the center of the reflecting portion base 201a in the axial direction of the second axis X2. For this reason, the base ends 291a and 292a of the detection cantilevers 291 and 292 are formed so as to be located slightly on the free ends 291b and 292b side from the center of the reflecting portion base 201a.

  The detection cantilevers 291 and 292 are formed such that the free ends 291b and 292b are heavier than the base ends 291a and 292a. Specifically, the thick portion (similar to the thick portions 91c and 92c of the detection cantilevers 91 and 92) is formed so that the thickness of the free ends 291b and 292b is thicker than the base ends 291a and 292a. Is formed.

  In the present embodiment, the inner piezoelectric actuators 281 and 282 have the same configuration as the outer piezoelectric actuators 101 and 102. Specifically, a plurality of (four in the illustrated example) inner piezoelectric cantilevers 231 to 234 each configured to bend and deform by piezoelectric driving are connected. In this case, the plurality of inner piezoelectric cantilevers 231 to 234 constituting the inner piezoelectric actuators 281 and 282 are orthogonal to the first axis X1 between the inner peripheral portion of the movable portion 9 and the outer peripheral portion of the reflecting portion base 1a. The inner piezoelectric cantilevers 231 to 234 are folded back with respect to the adjacent inner piezoelectric cantilevers while extending in the direction and arranged in the direction of the first axis X1 with a space therebetween. It is connected. Accordingly, the inner piezoelectric actuators 281 and 282 extend so as to meander with the direction orthogonal to the first axis X1 as the amplitude direction.

  One end portion of each inner piezoelectric actuator 281, 282 (the base end portion of the inner piezoelectric cantilever 234 closest to the movable portion 9) is connected to the inner peripheral portion of the movable portion 9 and the other end portion (most reflective portion). The tip of the inner piezoelectric cantilever 231 near the base 1a is connected to the outer periphery of the reflecting base 1a.

  As a result, the reflecting portion 201 is supported by the movable portion 9 via the inner piezoelectric actuators 281 and 282, and is moved to the movable portion 9 by bending deformation of the inner piezoelectric cantilevers 231 to 234 constituting the inner piezoelectric actuators 281 and 282. On the other hand, it can swing around the first axis X1.

  In the following description, the inner piezoelectric cantilevers 231 to 234 constituting the inner piezoelectric actuators 281 and 282 are respectively defined as the first, second, third, and fourth inner piezoelectric cantilevers in order from the reflecting portion 201 side. The inner piezoelectric cantilevers 231 and 233 may be referred to as odd-numbered inner piezoelectric cantilevers, and the inner piezoelectric cantilevers 232 and 234 may be referred to as even-numbered inner piezoelectric cantilevers.

  In the illustrated optical deflector A2, the number of the inner piezoelectric cantilevers 231 to 234 constituting each of the inner piezoelectric actuators 281 and 282 is four. However, the inner piezoelectric actuators 281 and 282 are configured by a larger number of inner piezoelectric cantilevers. Of course, you may make it comprise. Of course, the number of the inner piezoelectric cantilevers 231 to 234 of the inner piezoelectric actuators 281 and 282 may be different from the number of the piezoelectric cantilevers 31 to 34 of the outer piezoelectric actuators 101 and 102.

  The inner piezoelectric cantilevers 231 to 234 constituting the inner piezoelectric actuators 281 and 282 and the detection cantilevers 291 and 292 are the same as the inner piezoelectric cantilevers 231 to 234 constituting the outer piezoelectric actuators 101 and 102, etc. Further, the piezoelectric cantilever has a structure in which a layer of a lower electrode 5, a piezoelectric body 6, and an upper electrode 7 is laminated on a layer of a support 4 as a strain generating body (cantilever body).

  Each of the inner piezoelectric cantilevers 231 to 234 constituting the inner piezoelectric actuators 281 and 282 applies a driving voltage to the piezoelectric body 6 between the lower electrode 5 and the upper electrode 7, thereby supporting the support body 4 together with the piezoelectric body 6. Is bent and deformed. Further, the detection cantilevers 291 and 292 are configured such that a voltage corresponding to the bending deformation is output from the piezoelectric body 6 when the support body 4 and the piezoelectric body 6 are bent and deformed.

  In the following description, the piezoelectric body 6 disposed on the inner piezoelectric cantilevers 231 to 234 is referred to as a driving piezoelectric body 61, and the piezoelectric body 6 disposed on the detection cantilevers 291 and 292 is referred to as the detection piezoelectric body 62. Called.

  The connecting portions of the inner piezoelectric cantilevers 231 to 234 adjacent to each other of the inner piezoelectric actuators 281 and 282 are portions integrally connecting the supports 4 of the adjacent inner piezoelectric cantilevers 231 to 234, The connecting portion is not provided with the layers of the piezoelectric body 6 and the upper electrode 7.

  On the support base 11, in addition to the electrode pads of the first embodiment, two electrode pads 127 and 128 are provided as drive electrode pads for piezoelectrically driving the inner piezoelectric actuators 281 and 282, and the two electrode pads 143 are provided. , 144 are provided as detection electrode pads for acquiring the voltage output from the detection cantilevers 291, 292 according to the bending deformation of the detection cantilevers 291, 292.

  In the present embodiment, the drive electrode pad 121 is an upper electrode pad for applying a drive voltage between the upper electrode 7 and the lower electrode 5 of the odd-numbered inner piezoelectric cantilevers 231 and 233 of the inner piezoelectric actuator 281. The drive electrode pad 122 is an upper electrode pad for applying a drive voltage between the upper electrode 7 and the lower electrode 5 of the odd-numbered inner piezoelectric cantilevers 231 and 233 of the inner piezoelectric actuator 282.

  The drive electrode pad 127 is an upper electrode pad for applying a drive voltage between the upper electrode 7 and the lower electrode 5 of the even-numbered inner piezoelectric cantilevers 232 and 234 of the inner piezoelectric actuator 281. The drive electrode pad 128 is an upper electrode pad for applying a drive voltage between the upper electrode 7 and the lower electrode 5 of the even-numbered inner piezoelectric cantilevers 232 and 234 of the inner piezoelectric actuator 282.

  The detection electrode pad 143 is an upper electrode pad for acquiring a voltage output from the piezoelectric body 6 (that is, the detection piezoelectric body 62) of the detection cantilever 291. The detection electrode pad 144 is an upper electrode pad for acquiring a voltage output from the piezoelectric body 6 (that is, the detection piezoelectric body 62) of the detection cantilever 292.

  In the present embodiment, the lower electrode pad 131 is a common lower electrode pad for the upper electrode pads 121, 123, 124, 127, 141, and 143. The lower electrode pad 132 is a lower electrode pad common to the upper electrode pads 122, 125, 126, 128, 142, and 144.

  In each of the inner piezoelectric cantilevers 231 to 234 and the detection cantilevers 291 and 292, the configurations of the lower electrode 5, the piezoelectric body 6, and the upper electrode 7 are the same as those of the other piezoelectric cantilevers, and thus the description thereof is omitted.

  The drive electrode pads 121, 122, 127, and 128 are the upper electrodes 7 of the odd-numbered inner piezoelectric cantilevers 231 and 233 of the inner piezoelectric actuator 281 and the odd-numbered inner piezoelectric cantilevers 231 and 233 of the inner piezoelectric actuator 282, respectively. Upper electrode wiring (not shown) is connected to the upper electrode 7, the upper electrode 7 of the even-numbered inner piezoelectric cantilevers 232 and 234 of the inner piezoelectric actuator 281, and the upper electrode 7 of the even-numbered inner piezoelectric cantilevers 232 and 234 of the inner piezoelectric actuator 282. ).

  The detection electrode pads 143 and 144 are electrically connected to the upper electrode 7 of the detection cantilever 291 and the upper electrode 7 of the detection cantilever 292 via upper electrode wiring (not shown).

  The thick part provided in the detection cantilevers 291 and 292 of the reflecting portion base 201a is the surface from the surface opposite to the surface on which the lower electrode 5 and the like of the support 4 of the detection cantilevers 291 and 292 are provided. It protrudes toward the normal direction. The thick portions 91c and 92c are integrally formed by processing a semiconductor substrate (silicon substrate) composed of a plurality of layers.

  Here, in the present embodiment, the movable portion 9 corresponds to a “support portion” in the present invention. The outer piezoelectric actuators 101 and 102 correspond to “piezoelectric actuators” in the present invention. The piezoelectric cantilevers 31 to 34 of the outer piezoelectric actuators 101 and 102 correspond to “piezoelectric cantilevers” in the present invention. The piezoelectric bodies 6 of the piezoelectric cantilevers 31 to 34 of the outer piezoelectric actuators 101 and 102 correspond to the “driving piezoelectric body” in the present invention. The piezoelectric body 6 of the detection cantilevers 91 and 92 provided in the movable portion 9 corresponds to the “detection piezoelectric body” in the present invention. The inner piezoelectric actuators 281 and 282 correspond to “another piezoelectric actuator” in the present invention. The inner piezoelectric cantilevers 231 to 234 of the inner piezoelectric actuators 281 and 282 correspond to “another piezoelectric cantilever” in the present invention. The piezoelectric bodies 6 of the inner piezoelectric cantilevers 231 to 234 of the inner piezoelectric actuators 281 and 282 correspond to “another driving piezoelectric body” in the present invention. The piezoelectric body 6 of the detection cantilevers 291 and 292 provided on the reflecting portion base 201a corresponds to “another detection piezoelectric body” in the present invention. The second axis X2 corresponds to the “predetermined axis” in the present invention. The first axis X1 corresponds to “another axis” in the present invention.

  Next, the operation of the optical deflector A2 of this embodiment will be described.

  The swinging of the reflecting portion 201 (or the movable portion 9) about the second axis X2 is the same as in the first embodiment. The swinging of the reflecting part 201 around the first axis X1 is performed in the same manner as the swinging of the reflecting part 201 (or the movable part 9) around the second axis X2 by the outer piezoelectric actuators 101 and 102.

  Specifically, the control circuit outputs a first drive voltage for piezoelectrically driving the even-numbered inner piezoelectric cantilevers 232 and 234 of each of the inner piezoelectric actuators 281 and 282, and also outputs each of the inner piezoelectric actuators 281 and 282. A second drive voltage for piezoelectrically driving the odd-numbered inner piezoelectric cantilevers 231 and 233 is output. Here, the first drive voltage is a voltage signal having a waveform having an opposite phase to the waveform of the second drive voltage.

  At this time, the control circuit applies a first drive voltage between the lower electrode 5 and the upper electrode 7 of each of the even-numbered inner piezoelectric cantilevers 232 and 234 of each of the inner piezoelectric actuators 281 and 282, Each inner piezoelectric cantilever 231 to 234 is bent and deformed by piezoelectric driving. At the same time, the control circuit applies a second drive voltage between the lower electrode 5 and the upper electrode 7 of each of the odd-numbered inner piezoelectric cantilevers 231 and 233 of each of the outer piezoelectric actuators 101 and 102, thereby The inner piezoelectric cantilevers 231 to 234 are bent and deformed by piezoelectric driving.

  As a result, the front end portion of the inner piezoelectric cantilever 234 (the connection portion with the reflecting portion base 201a) and the front end portion of the inner piezoelectric cantilever 232 (the connection portion with the piezoelectric cantilever 233) are connected to each of the inner piezoelectric cantilevers 232 and 234. The even-numbered inner piezoelectric cantilevers 232 and 234 are bent and deformed so as to be displaced in the same direction with respect to the base end portion. The distal end of the inner piezoelectric cantilever 233 (the connecting portion with the inner piezoelectric cantilever 234) and the distal end of the inner piezoelectric cantilever 231 (the connecting portion with the inner piezoelectric cantilever 232) are the base ends of the inner piezoelectric cantilevers 231 and 233, respectively. The odd-numbered inner piezoelectric cantilevers 231 and 233 are bent and deformed so as to be displaced in the opposite direction to the inner piezoelectric cantilevers 232 and 234 with respect to the portion. Thereby, in the inner piezoelectric actuators 281 and 282, an angular displacement having a magnitude obtained by accumulating the magnitude of the bending deformation of each inner piezoelectric cantilever 231 to 234 is generated.

  As a result, in the inner piezoelectric actuators 281 and 282, as in the outer piezoelectric actuators 101 and 102, either a voltage signal having a frequency near the mechanical resonance frequency of the optical deflector A2 or a voltage signal having a non-resonance frequency is applied. Even in this case, it is possible to obtain a sufficient deflection angle capable of optical scanning, and when applying a DC voltage signal, the inner piezoelectric element can be controlled by controlling the magnitude of the voltage signal. The effect that an arbitrary output can be obtained from the actuators 281 and 282 is obtained.

  As described above, in the optical deflector A2, even when it swings around any of the first axis X1 and the second axis X2, linearly according to the magnitude of the DC voltage applied as the drive voltage. Since the deflection angle can be controlled, an arbitrary deflection angle can be obtained at an arbitrary speed.

  Thus, when the reflecting portion 201 is swung around the first axis X1 by the inner piezoelectric actuators 281 and 282, the detection cantilevers 291 and 292 are bent and deformed according to the swing. Along with this bending deformation, the piezoelectric body 6 (that is, the detecting piezoelectric body 62) of the detection cantilevers 291 and 292 is bent and deformed. Accordingly, a voltage signal (detection voltage) corresponding to the swinging of the reflecting portion 201 is output from the detection piezoelectric body 62 of the detection cantilevers 291 and 292.

  At this time, since the detecting piezoelectric body 62 is not provided in the inner piezoelectric actuators 281 and 282, the area of the piezoelectric body 6 (that is, the driving piezoelectric body 61) occupying on each inner piezoelectric cantilever 231 to 234 is reduced. do not do. Thereby, it is possible to suppress the bending deformation of each of the inner piezoelectric cantilevers 231 to 234 from being reduced, and as a result, it is possible to suppress a decrease in the deflection angle around the first axis X1 of the optical deflector A2.

  Further, the detection piezoelectric body 62 is disposed on detection cantilevers 291 and 292 different from the inner piezoelectric cantilevers 231 to 234 that support the drive piezoelectric body 61. Therefore, the sizes (areas) of the detection cantilevers 291 and 292 and the detection piezoelectric body 62 are set so that the detection voltage output from the detection piezoelectric body 62 can be determined from the detection voltage and the noise component. ) Can be adjusted, and the deflection angle of the optical deflector A2 can be accurately detected.

  The detection cantilevers 291 and 292 are formed such that the free ends 291b and 292b are thicker than the base ends 291a and 292a. As a result, in the detection cantilevers 291 and 292, the free ends 291b and 292b are heavier than the base ends 291a and 292a. Since the detection cantilevers 291 and 292 move from the base ends 291a and 292a to the free ends 291b and 292b, the bending deformation of the detection cantilevers 291 and 292 increases as the free ends 291b and 292b are heavier (that is, The bending deformation of the detection cantilevers 291 and 292 corresponding to the swing of the movable portion 9 is increased). As a result, the voltage output from the detection piezoelectric body 62 becomes larger than the area of the detection piezoelectric body 62, and the deflection angle of the optical deflector A2 can be detected with high accuracy.

  The detection cantilevers 291 and 292 are formed such that the longitudinal direction thereof is orthogonal to the axial direction of the first axis X1. Accordingly, the detection cantilevers 291 and 292 are easily bent and deformed in accordance with the swinging of the reflecting portion 201. Therefore, the voltage output from the detection piezoelectric body 62 is increased, and the deflection angle of the optical deflector A2 can be detected with high accuracy.

  Further, the detection cantilevers 291 and 292 are formed such that their base ends 291a and 292a are located closer to the free ends 291b and 292b of the detection cantilevers 291 and 292 than the second axis X2. In other words, the detection cantilevers 291 and 292 are formed so as not to include the second axis X <b> 2 that is the central axis of the swing of the reflection unit 201. Accordingly, the detection cantilevers 291 and 292 are easily bent and deformed according to the swinging of the reflecting portion 201, and the deflection angle of the optical deflector A2 can be detected with high accuracy.

  In the first and second embodiments, the free ends 91b, 92b, 291b, and 292b of the detection cantilevers 91, 92, 291, and 292 are compared to the base ends 91a, 92a, 291a, and 292a. However, the free end side and the base end side may be configured to have the same weight. Even in this case, it is possible to obtain an effect of suppressing a decrease in the deflection angle of the optical deflector and accurately detecting the deflection angle of the optical deflector.

  In the first and second embodiments, the free ends 91b, 92b, 291b, and 292b of the detection cantilevers 91, 92, 291, and 292 are set to the base ends 91a, 92a, 291a, and 292a. In order to be configured to be heavier in comparison, the free end 91b, 92b, 291b, 292b side is configured to be thicker than the base ends 91a, 92a. However, even if these thicknesses are the same, the weight on the free end side becomes heavier than the base end side, for example, by using different materials (using a material having a large specific gravity on the free end side). If it is the aspect comprised by this, the detection voltage with respect to the area of the piezoelectric material for a detection will become large, and the effect that the deflection angle of an optical deflector can be detected accurately will be acquired.

  In the first and second embodiments, the detection cantilevers 91, 92, 291, 292 are located on the free ends 91 b, 92 b, 291 b, 292 b side of the detection cantilevers 91, 92, 291, 292. The support 4 is provided so as to protrude from the surface opposite to the surface on which the lower electrode 5 and the like are provided toward the normal direction of the surface, but the protruding direction is not limited thereto. For example, a predetermined member may be further laminated on the oxide film or the like covering the upper electrode 7 and the electrode wiring disposed thereon to provide a thickness. As an example, an etching process or the like may be performed so that the free end side is thicker than the base end side.

  In the first and second embodiments, the detection cantilevers 91, 92, 291, and 292 have their longitudinal directions orthogonal to the axial direction of the second axis X 2 or the first axis X 1. However, the present invention is not limited to this, and if the detection cantilever bends and deforms in response to the swing by the swing of the piezoelectric actuator or another piezoelectric actuator, the detection cantilever is , Any orientation may be adopted.

  In the first and second embodiments, the detection cantilevers 91, 92, 291, 292 have base ends 91 a, 92 a, 291 a, 292 a from the second axis X 2 or the first axis X 1. Is a mode in which the detection cantilevers 91, 92, 291, and 292 are formed on the free ends 91 b, 92 b, 291 b, and 292 b side, but is not limited to this mode.

  In the first embodiment and the second embodiment, the piezoelectric cantilevers 31 to 34 of the outer piezoelectric actuators 101 and 102 and the inner piezoelectric cantilevers 231 to 234 of the inner piezoelectric actuators 281 and 282 have the respective lengths. Although it is the aspect currently formed (or substantially the same), it is not restricted to this, For example, the outside piezoelectric actuators 101 and 102 may be comprised as demonstrated below.

  Specifically, the length of the first piezoelectric cantilever 31 and the fourth piezoelectric cantilever 34 in the first embodiment is formed to be less than half the length of the second piezoelectric cantilever 32 and the third piezoelectric cantilever 33, The distal end portion of the first piezoelectric cantilever 31 is connected to the vicinity of the central portion of the outer peripheral portion of the movable portion 9 in the first axis X1 direction, and the proximal end portion of the fourth piezoelectric cantilever 34 is the inner periphery of the support base 11. The aspect connected with the center part vicinity in the 1st axis | shaft X1 direction among parts may be sufficient.

  At this time, the detection cantilevers 91 and 92 provided in the movable portion 9 are at the same position as the first piezoelectric cantilever 31 in the second axis X2 direction and in the first axis X1 direction. It is formed at a position on the opposite side to. At this time, the base ends 91a and 92a of the detection cantilevers 91 and 92 are on the connecting portion side where the first piezoelectric cantilever 31 and the movable portion 9 are connected in the axial direction of the first axis X1. Free ends 91b and 92b of the detection cantilevers 91 and 92 are provided on the side opposite to the part.

  In the optical deflector A2 as in the second embodiment, at least one of the outer piezoelectric actuators 101 and 102 and the inner piezoelectric actuators 281 and 282 may have the above-described mode.

  As described above, the piezoelectric actuator and the other piezoelectric actuator according to the present invention can swing the mirror portion around a predetermined axis or swing the reflecting portion around another axis by piezoelectric driving. If there is, it is not limited to the aspect of the present embodiment, but may be other aspects.

  Moreover, in the said 1st Embodiment or 2nd Embodiment, although it is an aspect which rocks | fluctuates an optical deflector around the 2nd axis | shaft of the 1st axis | shaft X1 and the 2nd axis | shaft X2, it is not restricted to this, It is only about 1 axis | shaft It is also possible to have a mode that swings. That is, the optical deflector may be configured such that the plurality of piezoelectric cantilevers swing the reflecting portion only around a predetermined axis (for example, the second axis X2) by the piezoelectric actuator. More specifically, the optical deflector is configured such that, for example, in the optical deflector A1 of the first embodiment, the inner piezoelectric actuators 81 and 82 are not provided, and the reflecting portion 1 is fixed to the movable portion 9. There may be. As another example, in the optical deflector A1 of the first embodiment, the inner piezoelectric actuators 81 and 82 are not provided, and the outer piezoelectric actuators 101 and 102 are the inner piezoelectric actuators 81 and 82 of the first embodiment. The aspect comprised like 82 may be sufficient.

A1 ... Optical deflector, X1 ... first axis, X2 ... second axis, 1 ... reflecting part, 1b ... reflecting surface, 61 ... piezoelectric element for driving, 62 ... piezoelectric element for detection, 9 ... moving part, 91a, 92a ... proximal end, 91b, 92b ... free end, 101, 102 ... outer piezoelectric actuator, A2 ... optical deflector, 201 ... reflector, 201b ... reflecting surface, 291a, 292a ... proximal end, 291b, 292b ... free end.

Claims (6)

A mirror section having a reflecting surface; and a piezoelectric actuator that swings the mirror section about a predetermined axis (X2) by piezoelectric driving, the piezoelectric actuator including a driving piezoelectric body to which a driving voltage is applied; An optical deflector comprising: a supporting body that supports the driving piezoelectric body and bends and deforms together with the driving piezoelectric body;
The mirror portion is provided with a detection cantilever that bends and deforms in response to the swinging of the mirror portion around the predetermined axis, and the detection cantilever is bent by the detection cantilever. An optical deflector that supports a piezoelectric body for detection that bends and deforms with deformation.   2. The optical deflector according to claim 1, wherein the detection cantilever is formed such that a free end side thereof is heavier than a base end side.   3. The optical deflector according to claim 1, wherein the detection cantilever is formed so that a longitudinal direction thereof is orthogonal to an axial direction of the predetermined axis. .   4. The optical deflector according to claim 3, wherein the detection cantilever is formed such that a base end thereof is positioned on a free end side of the detection cantilever with respect to the predetermined axis. Optical deflector. In the optical deflector according to any one of claims 1 to 4,
The piezoelectric actuator includes a plurality of piezoelectric cantilevers having the driving piezoelectric body and the support,
The plurality of piezoelectric cantilevers are connected at their ends so as to accumulate each bending deformation. The optical deflector according to any one of claims 1 to 5,
The mirror section includes a reflecting section having the reflecting surface, another piezoelectric actuator that swings the reflecting section around an axis (X1) different from the predetermined axis by piezoelectric driving, and the another piezoelectric actuator. A support part for supporting the reflection part via
The another piezoelectric actuator includes another driving piezoelectric body to which a driving voltage is applied, and a plurality of other piezoelectric cantilevers that support the other driving piezoelectric body and bend and deform together with the other driving piezoelectric body. With
The plurality of other piezoelectric cantilevers are connected at their ends so as to accumulate each bending deformation,
The reflective portion is provided with another detection cantilever that bends and deforms in response to the swing of the reflective portion when the reflective portion swings around the other axis. An optical deflector which supports another detection piezoelectric body that bends and deforms along with the bending deformation of the detection cantilever.