JP5447481B2 - Optical scanner - Google Patents

Description

  The present invention relates to an optical scanner that scans light such as a laser.

  Currently, an optical scanner that scans light such as laser light with a swinging mirror is known. As an example of the optical scanner, a mirror unit that is swingably supported by a torsion beam unit is swung by a driving unit such as a piezoelectric element. For example, Patent Document 1 discloses an example of an optical scanner having a structure formed of stainless steel as a conductive material. In the optical scanner of Patent Document 1, a pair of drive units made of piezoelectric elements are provided on both sides of the mirror unit with a position on the structure. And a structure is installed on a base stand.

JP2011-27881A

  In an optical scanner, vibration is applied to a structure including a mirror part in order to swing the mirror part. The torsion beam vibrates by the vibration applied to the structure. However, this vibration causes not only torsional vibration of the torsion beam part but also vibration of the structure itself. The vibration of the structure itself causes a problem that abnormal noise is generated when the optical scanner is driven due to the contact between the structure, the base base, and the drive unit. If the drive frequency of the optical scanner is within the range of the sound frequency of human audible range, this abnormal sound can be heard and the user may feel uncomfortable. In addition, since the driving force for originally swinging the mirror portion is used for generating abnormal noise, the driving efficiency is reduced, and as a specific example, the driving voltage necessary to obtain the desired swinging angle of the mirror portion is obtained. A rise occurs. For this reason, it is desirable to suppress the vibration of the structure when the mirror portion is swung.

  An object of the present invention is to provide an optical scanner capable of suppressing vibration of a structure when a mirror portion is swung.

In order to solve the above problems, one aspect of the present invention provides a mirror unit having a reflecting surface that reflects incident light and configured to be swingable about a first axis, and from one end of the mirror unit. A first torsion beam portion extending parallel to the first axis, and a second torsion beam extending from the other end of the mirror portion in a direction parallel to the first axis and opposite to the first torsion beam portion. And a main body connected to the ends of the first torsion beam and the second torsion beam and spaced apart from the mirror and extending in a direction intersecting the first axis. A structure, a pedestal to which a part of the structure is fixed, and the main body, the structure is vibrated by applying a driving voltage, and the mirror portion is rotated around the first axis. A drive unit that can be swung, and the main body is parallel to the first axis. And a first through hole provided at a position farther from the mirror portion than the end of the first torsion beam portion and extending in a direction intersecting the first axis, and the first through hole in a direction parallel to the first axis. A second through hole provided at a position farther from the mirror part than the end of the two torsion beam parts and extending in a direction intersecting the first axis; and the first through hole in a direction parallel to the first axis A first fixed portion that is provided at a position farther from the mirror portion and is fixed to the pedestal, and is separated from the mirror portion than the second through hole in a direction parallel to the first axis. A second fixed portion that is provided at a position and is fixed to the pedestal; and extends in a direction along the first axis, and bridges the first through hole so as to bridge the main body portion and the first fixed portion. A first bridging part connecting the parts; Serial extends in a direction along the first axis, the second bridging portion connecting the second fixation portion and the body portion by bridging the second through-holes, only contains the first bridging portion Has a first separation bridging member that is separated from the first axis in a direction intersecting the first axis and connects the main body and the first fixed portion by bridging the first through hole. The second bridging portion is separated from the first axis in a direction intersecting the first axis, and connects the main body portion and the second fixed portion by bridging the second through hole. An optical scanner having a second separation bridging member .

The main body portion and the first fixed portion are connected by the first bridging portion that bridges the first through hole. The main body portion and the second fixed portion are connected by the second bridging portion that bridges the second through hole. Since the main body part is connected to the first fixed part and the second fixed part by the first bridging part and the second bridging part, when the mirror part is swung, the displacement of the main body part of the structure is not changed. Limited. As a result, it is possible to suppress the vibration amount in the main body portion of the structure when the mirror portion is swung.
Further, the first separation bridging member and the second separation bridging member are provided at positions separated from the first axis with respect to the direction intersecting the first axis. By providing the first separation bridging member and the second separation bridging member, the amount of vibration in the main body can be further suppressed. Furthermore, by adjusting the separation distance from the first axis, it is also possible to adjust the characteristics of the optical scanner, specifically, the degree of vibration suppression in the main body.

  In addition, the first bridging portion includes a first central bridging member that includes the first axis and connects the main body portion and the first fixed portion by bridging the first through hole, The second bridging portion may include a second central bridging member that includes the first axis and connects the main body portion and the second fixed portion by bridging the second through hole.

  The first center bridging member and the second center bridging member include a first axis. That is, the first center bridging member and the second center bridging member are present on the longitudinal extension of the first torsion beam portion and the second torsion beam portion. Thereby, when the mirror part is oscillated, the displacement of the part other than the mirror part is suppressed without hindering the swaying of the mirror part. Accordingly, it is possible to obtain stable optical characteristics in addition to suppressing vibration amount and reducing abnormal noise in the main body.

  Further, the main body portion is formed in line symmetry with respect to the first axis, and the pair of the first separation bridge member and the second separation bridge member are in line symmetry with respect to the first axis. It may be provided.

  Since the main body is line-symmetric with respect to the first axis, the magnitude of vibration in the main body is substantially line-symmetric with respect to the first axis. Therefore, by providing a pair of the first bridging member and the second bridging member so as to be axisymmetric with respect to the first axis, it is possible to further suppress vibration in the main body.

  In the direction intersecting the first axis, the first separation bridge member has a separation interval from the first axis of 15 to 15 of the distance between the first axis and the end of the first through hole. Provided at a position of 65%, and in the direction intersecting the first axis, the second spacing bridge portion is spaced from the first axis by an interval between the first axis and the end of the second through hole. It may be provided at a position that is 15 to 65% of the distance between the two.

  In the direction intersecting the first axis, the first separation bridge member and the second separation bridge member have a separation interval from the first axis between the first axis and the end of the first through hole and the second through hole. It is provided in the position which becomes 15 to 65% with respect to the distance. As shown in an embodiment described later, by providing the first separation bridge member and the second separation bridge member at this position, it is possible to sufficiently reduce the vibration of the main body.

  The first fixed portion and the second fixed portion are fixed to the base at a plurality of fixed portions, and the plurality of fixed portions are arranged in the direction intersecting the first axis in the first direction. You may provide in the position spaced apart with respect to a bridging part and the said 2nd bridging part.

  The plurality of fixed portions where the first fixed portion and the second fixed portion are fixed with respect to the pedestal are spaced apart from the first bridging portion and the second bridging portion in a direction intersecting the first axis. Provided. As shown in an embodiment described later, this configuration makes it possible to suppress warping in the first torsion beam and the second torsion beam. As a result, it is possible to suppress the positional deviation of the mirror part in the vertical direction and the scanning abnormality, and to maintain the optical characteristics of the optical scanner.

  According to the present invention, it is possible to obtain an optical scanner capable of suppressing vibration in the main body portion of the structure when the mirror portion is swung.

(A) The top view of the optical scanner 100 which concerns on 1st Embodiment, (B) AA sectional drawing of the optical scanner 100, (C) BB sectional drawing of the optical scanner 100. FIG. The figure explaining the change of the maximum vibration amount of the main-body part 114 by the presence or absence of the center bridge | bridging 116. FIG. The figure explaining the curvature amount of the 1st twist beam part 112a and the 2nd twist beam part 112b by the position of the fixed part FP. (A) The top view of the optical scanner 200 which concerns on 2nd Embodiment, (B) AA sectional drawing of the optical scanner 200, (C) BB sectional drawing of the optical scanner 200. FIG. The figure explaining the change of the maximum vibration amount of the main-body part 214 by the position of the 1st separation bridge 218a and the 2nd separation bridge 218b. (A) The top view of the optical scanner 300 which concerns on 3rd Embodiment, (B) AA sectional drawing of the optical scanner 300, (C) BB sectional drawing of the optical scanner 300. The figure explaining the change of the maximum vibration amount of the main-body part 314 by the position of the 1st separation bridge 318a and the 2nd separation bridge 318b.

<First Embodiment>
Hereinafter, a first embodiment reflecting one aspect of the present invention will be described with reference to the drawings. Note that the drawings to be referred to are used to explain technical features that can be adopted by the present invention, and the described configuration is merely an illustrative example rather than a limitation. For example, in each configuration described below, a predetermined configuration may be omitted or replaced with another configuration. Moreover, you may make it include another structure.

[Configuration of Optical Scanner 100]
As shown in FIG. 1, the optical scanner 100 includes a structure 110 and a pedestal 120. The mirror unit 130 is swung around the first axis s as a central axis by the piezoelectric element 117. By this swinging, the light incident on the mirror unit 130 is scanned.

  The structure 110 is a plate-like structure having a rectangular shape in plan view, which includes a pair of short sides parallel to the front-rear direction and a pair of long sides parallel to the left-right direction. Note that the front-rear direction is parallel to the first axis s. The structure 110 includes a swinging part 111, a first torsion beam part 112a, a second torsion beam part 112b, and a main body part 114. A piezoelectric element 117 is provided on one surface (for example, the upper surface) of the main body 114. In the present embodiment, a pair of piezoelectric elements 117 are provided so as to be line symmetric with respect to the first axis s. The structure 110 is made of a metal material such as stainless steel or titanium. However, the structure 110 may be formed of a semiconductor material such as silicon. The structure 110 is parallel to the front, rear, left and right surfaces in FIG. Moreover, the size of the structure 110 in the front-rear direction, the left-right direction, and the up-down direction is, for example, about 20 mm, 30 mm, and 0.1 mm, respectively.

  One end of the first torsion beam portion 112 a is connected to the front end portion of the swinging portion 111. The first torsion beam portion 112 a extends in the forward direction from the connection position with the swinging portion 111. One end of the second torsion beam portion 112 b is connected to the rear end portion of the swinging portion 111. The second torsion beam portion 112 b extends backward from the connection position with the swinging portion 111. The first torsion beam portion 112a and the second torsion beam portion 112b are simply referred to as the torsion beam portion 112 when not distinguished from each other. In the center of the main body 114, a rectangular third through-hole C having a long axis along the front-rear direction is formed. The third through hole C defines the swinging part 111 and the torsion beam part 112 with respect to the main body part 114. Here, the first axis s passes through the center of the torsion beam portion 112. That is, the swinging portion 111 is elastically supported by the torsion beam portion 112 so as to be swingable about the first axis s. That is, the torsion beam portion 112 has a role as a torsion bar that supports the swinging portion 111 so as to be swingable about the first axis s.

  The main body 114 is connected to the front end of the first torsion beam 112a and the rear end of the second torsion beam 112b. The main body 114 extends from the connecting position with the torsion beam 112 in a direction away from the swinging part 111 and intersecting the first axis s. In the present embodiment, the main body 114 extends from the connecting portion with the torsion beam 112 to both sides in the left-right direction.

  A first through hole A and a second through hole B are formed in the main body 114. The first through hole A is provided on the front side of the first torsion beam portion 112a, in other words, at a position farther from the mirror portion 130 than the end portion of the first torsion beam portion 112a in the front-rear direction. The 1st through-hole A is comprised by the rectangle, and the longitudinal direction is parallel to the left-right direction. The second through hole B is provided on the rear side of the second torsion beam portion 112b, in other words, at a position farther from the mirror portion 130 than the end portion of the second torsion beam portion 112b in the front-rear direction. The 2nd through-hole B is formed in a rectangle, and the longitudinal direction is parallel to the left-right direction. However, the first through hole A and the second through hole B may have any shape as long as the main body 114 and the fixed portion 115 can be separated from each other.

  A fixed portion 115 a that is fixed to the pedestal 120 is provided at a position farther from the mirror portion 130 than the through hole A in the front-rear direction, that is, in front of the through hole A. A fixed portion 115b fixed to the pedestal 120 is provided at a position farther from the mirror portion 130 than the through hole B in the front-rear direction, that is, at the rear side of the through hole B. In addition, when not distinguishing the to-be-fixed part 115a and the to-be-fixed part 115b, it only calls the to-be-fixed part 115. FIG. The fixed portion 115 is a band-like region extending in the left-right direction. The fixed portion 115 is connected to the main body portion 114 at both ends in the left-right direction and a first bridging portion and a second bridging portion which will be described later.

  The first center bridging member 116a includes the first axis s, and bridges the first through hole A to connect the main body 114 and the first fixed portion 115a. In other words, the first center bridging member 116a is formed on the same straight line as the first torsion beam portion 112a and extends in the front-rear direction. That is, the through hole A is divided into right and left by the first center bridging member 116a at the center in the left-right direction. The first center bridging member 116a is an example of a first bridging portion that extends in a direction along the first axis s. The second center bridging member 116b includes the first axis s, and bridges the second through hole B to connect the main body 114 and the second fixed portion 115b. In other words, the second center bridging member 116b is formed on the same straight line as the second torsion beam portion 112b and extends in the front-rear direction. That is, the through-hole B is divided into right and left by the second center bridging member 116b at the center in the left-right direction. The second center bridging member 116b is an example of a second bridging portion that extends in the direction along the first axis s. Further, when the first center bridging member 116a and the second center bridging member 116b are not distinguished, they are simply referred to as the center bridging member 116.

  A piezoelectric element 117 as an example of a drive unit is provided on the upper surface of the main body 114. A pair of the piezoelectric elements 117 is provided at an intermediate position in the front-rear direction of the main body 117 and is symmetrical with respect to the first axis s at both ends in the left-right direction. However, the piezoelectric element 117 may be provided at a position other than this. For example, the piezoelectric elements 117 may be provided on the upper and lower surfaces of the main body 114. The piezoelectric element 117 is formed by laminating 0.2 μm to 0.6 μm of gold, platinum, or the like as an electrode layer on both surfaces of a piezoelectric material such as lead zirconate titanate formed into a flat plate having a thickness of 30 μm to 100 μm, for example. It is formed by doing. The piezoelectric element 117 and the main body 114 are bonded with a conductive adhesive. A fine metal wire (not shown) such as gold is connected to the upper surface of the piezoelectric element 117 by wire bonding or the like.

  On the upper surface of the oscillating portion 111, a mirror portion 130 that reflects light such as a laser is fixed. The rectangular mirror part 130 in plan view is configured separately from the oscillating part 111 by a dielectric having transparency to visible light, such as sapphire or diamond. A metal thin film such as aluminum or silver is formed on the upper surface or the lower surface of the mirror unit 130 by a method such as sputtering or vapor deposition in order to reflect light such as laser. The oscillating part 111 and the mirror part 130 are fixed with a thermosetting adhesive such as epoxy, phenol or silicon. The swinging part 111 and the mirror part 130 are provided symmetrically with respect to the first axis s. In addition, without using a separate mirror unit 130, a mirror surface processing such as polishing or formation of a reflective film is performed on the upper surface of the oscillating unit 111 to provide a reflecting surface, and the oscillating unit 111 itself is used as the mirror unit. It does not matter.

  The pedestal 120 is a plate-like member formed in a rectangular shape. The long side of the pedestal 120 is parallel to the left-right direction. The short side of the pedestal 120 is parallel to the front-rear direction. In the center of the pedestal 120, a rectangular through hole whose longitudinal direction extends in the left-right direction is provided. The structure 110 is fixed to the upper surface of the pedestal 120 at the fixed portion 115. The left and right ends of the main body 114 are separated from the pedestal 120 in the left-right direction. The vertical thickness of the pedestal 120 is sufficiently larger than the vertical thickness of the structure 110, for example, about 1 mm. Therefore, even if the optical scanner 100 is driven, the pedestal 120 is hardly deformed. In other words, when the optical scanner 100 is driven, the fixed portion 115 is hardly deformed integrally with the base 120, and the main body 114 is mainly deformed. The pedestal 120 is made of a metal material such as stainless steel, for example.

  The fixed portion 115 and the pedestal 120 are fixed at a plurality of fixed portions FP (shaded circle portions in FIG. 1). The fixed portion FP is a region having a diameter of about several millimeters, for example. Fixing at the fixing portion FP is achieved by laser welding or a conductive thermosetting adhesive. The fixed portions FP are aligned in a line in the left-right direction at the fixed portion 115. The fixed part FP is provided in the vicinity of the connection part of the fixed part 115 with the main body 114. However, the fixed portion FP is provided at a position separated from the center bridging member 116 in the left-right direction. In other words, the fixed portion FP is not provided on the extension line in the front-rear direction of the center bridging member 116. The reason will be described later with reference to FIG.

[Driving of optical scanner 100]
Since the structure body 110 is made of metal, the piezoelectric element 117 can be deformed by applying a voltage between the structure body 110 and a metal thin wire connected to the upper surface of the piezoelectric element 117. The main body 114 is vibrated by the deformation of the piezoelectric element 117. A drive signal is periodically applied to the piezoelectric element 117 provided on the right side and the piezoelectric element 117 provided on the left side so as to have opposite phases. When the frequency of the drive signal corresponds to the frequency necessary for the resonance drive of the optical scanner 100, a plate wave is excited in the main body 114 with the deformation of the piezoelectric element 117. The plate wave is transmitted to the swing part 111 via the main body part 114 and the torsion beam part 112, so that the swing part 111 swings around the first axis s at a predetermined resonance frequency. Here, the structure 110 is fixed to the pedestal 120 at the fixed portion 115, and the main body 114 is in a state of being suspended in the air by the pedestal 120. Therefore, when the optical scanner 100 is driven, the main body 114 is displaced in the vertical direction. Since the torsion beam portion 112 is provided at a position that becomes a vibration node of the main body portion 114, even if the main body portion 114 is displaced in the vertical direction, the torsion beam portion 112 is suppressed from being displaced in the vertical direction. Note that the frequency of the drive signal may not exactly match the resonance frequency of the optical scanner 100. The frequency of the drive signal may be appropriately offset from the resonance frequency of the optical scanner 100 according to the Q value of the optical scanner 100 and the linearity of the frequency characteristics.

[Create Optical Scanner 100]
A production process of the optical scanner 100 will be described. Here, the case where the structure 110 is made of metal will be described as an example. First, a metal plate (for example, stainless steel or titanium) constituting the structure 110 is divided into a size equal to the outer shape of the structure 110. And the 1st through-hole A, the 2nd through-hole B, and the 3rd through-hole C are formed by performing a predetermined removal process with respect to the divided | segmented metal plate. By forming the first through hole A, the second through hole B, and the third through hole C, the swinging portion 111, the torsion beam portion 112, the main body portion 114, the fixed portion 115, and the center bridging member 116 are formed. The predetermined removal processing includes, for example, etching, press processing, electric discharge processing, laser processing, and the like. As an example, when wet etching is performed, a resist film for masking is formed at a position of the divided metal plate excluding the first through hole A, the second through hole B, and the third through hole C. . Thereafter, after the outer shape of the structure 110 is formed by wet etching, the resist film is removed. It should be noted that, after the outer shapes of the plurality of structures 110 are formed on a metal plate that is sufficiently larger than the outer shape of the structures 110, a large number of pieces can be divided into individual structures.

  Next, bulk piezoelectric elements 117 having electrode layers on both sides of the piezoelectric material in advance are mounted on the structure 110. This mounting is performed using, for example, a conductive adhesive containing a conductive material such as a metal filler in a synthetic resin material such as epoxy, acrylic or silicon. Specifically, the piezoelectric element 117 is installed on the conductive adhesive applied to the main body 114 of the structure 110. After the piezoelectric element 117 is installed, the conductive adhesive is cured by placing the structure 110 in a heating furnace maintained in an atmosphere of 100 to 200 ° C. for 30 to 60 minutes. Thus, the mounting of the piezoelectric element 117 is completed.

  Next, the pedestal 120 is created. The outer shape of the pedestal 120 is obtained by performing removal processing such as etching or pressing on the constituent material of the pedestal 120, as in the case of the structure 110.

  Next, the pedestal 120 and the structure 110 are fixed at a plurality of fixed positions FP. As described above, this fixing is performed using laser welding or a conductive thermosetting adhesive. Therefore, the structure 110 and the pedestal 120 are in an electrically connected state.

  Finally, signal lines are connected to the piezoelectric element 117 and the pedestal 120 by wire bonding. This signal line is connected to an AC power source (not shown). When the optical scanner 100 is driven, a drive signal is supplied between the piezoelectric element 117 and the pedestal 120 via this signal line. Thus, the creation process of the optical scanner 100 is completed.

[Effects of bridging part]
The degree of vibration suppression in the main body 114 of the structure 110 due to the provision of the center bridging member 116 will be described with reference to FIG. The maximum amount of vibration is the amount of vibration at a position where the amount of displacement in the vertical direction of the main body 114 is maximized during driving. The position where the displacement amount is maximum is, for example, a position where the piezoelectric element 117 of the main body 114 is provided. Further, the maximum vibration amount is expressed as a percentage by dividing by the maximum displacement amount in the vertical direction of the mirror unit 130 during driving. In the case of the optical scanner 100 shown in FIG. 1, the maximum vibration amount in the main body 114 during driving is “20.9%”. On the other hand, in the case of an optical scanner in which the center bridging member 116 does not exist, the maximum vibration amount is “27.0%”. Therefore, by providing the center bridging member 116, the maximum vibration amount in the main body 114 is suppressed by about 20%. The values shown in FIG. 2 are values obtained by a simulation performed based on parameters such as the shape and material of the optical scanner in which the optical scanner 100 and the center bridging member 116 do not exist.

[Effects of the position of the fixed part FP]
In the case of fixing using laser welding or a thermosetting adhesive, the temperature of the structure 110 and the pedestal 120 at the time of fixing is higher than the normal temperature when the optical scanner 100 is driven. When there is a difference in the coefficient of thermal expansion between the structure 110 and the pedestal 120, the amount of reduction when the structure 110 and the pedestal 120 return to normal temperature after the temperature rise during fixation differs. Due to the difference in the reduction amount, the structure 120 is warped. This warpage leads to the occurrence of stress and distortion in the vertical direction. When the torsion beam 112 is warped, it causes a positional shift in the vertical direction of the mirror 130 and scanning abnormality such as wobble. In order to suppress the warp, for example, methods such as reducing the intensity of the laser used for welding and reducing the area to be bonded can be considered. If these methods are applied, the warpage itself is certainly reduced. However, since the joint strength between the structure 110 and the pedestal 120 is lowered, it cannot be applied practically.

  In the present embodiment, the fixed portion FP is provided at a position separated from the center bridging member 116 in the left-right direction. If the fixed portion FP is provided on the extension line in the front-rear direction of the center bridging member 116, the difference in reduction amount that occurs when the temperature returns from the temperature at the time of fixing to the normal temperature is twisted via the center bridging member 116. Directly transmitted to the beam 112. As a result, the torsion beam portion 112 is greatly warped. On the other hand, when the fixed portion FP is provided at a position separated from the center bridging member 116 as in the present embodiment, the difference in the reduction amount is absorbed to some extent by the deformation of the fixed portion 115 in the front-rear direction. As a result, the difference in the reduction amount is not directly transmitted to the torsion beam portion 112, and as a result, the warp of the torsion beam portion 112 is suppressed.

  The horizontal axis in FIG. 3 indicates the position of the torsion beam portion 112 in the front-rear direction. However, the horizontal axis of FIG. 3 has the front end of the first center bridging member 116a as the start point and the rear end of the second center bridging member 116b as the end point. Moreover, since the upper surface of the mirror part 130 is located upward with respect to the torsion beam part 112, the measured value of the position where the mirror part 130 is provided is not obtained. The vertical axis in FIG. 3 indicates the amount of warping of the torsion beam portion 112 (and the center bridging member 116) in the vertical direction when the starting point position of the horizontal axis is “0”. A plot indicated by a solid line and a black circle and a plot indicated by a broken line and a black triangle are actually measured values in the optical scanner 100. The difference between the two is the difference in the created samples. The plots indicated by dotted lines and crosses and the plots indicated by alternate long and short dash lines and white squares are obtained when the fixed part FP is provided on the extension line in the front-rear direction of the center bridging member 116 in the fixed part 115. It is actual measurement data. The difference between the two is the difference in the created samples.

  As apparent from FIG. 3, when the fixed portion FP is provided at a position separated from the central bridging member 116 as compared with the case where the fixed portion FP is provided on the extension line in the front-rear direction of the central bridging member 116, the torsion beam The amount of warpage of the portion 112 is suppressed by about 1/3 to 1/4. As a result, the vertical misalignment of the mirror unit 130 and scanning anomalies such as wobble can be suppressed, and the optical characteristics of the optical scanner 100 can be maintained.

Second Embodiment
[Configuration of Optical Scanner 200]
3 shows a second embodiment reflecting another aspect of the present invention. The optical scanner 200 according to the second embodiment differs from the optical scanner 100 according to the first embodiment in the shape of the structure 210. Therefore, in the optical scanner 200, the same components as those in the optical scanner 100 are given the same numbers, and the description thereof is omitted.

  As shown in FIG. 4, the optical scanner 200 includes a structure 210 and a pedestal 120. The structure 210 is different from the structure 110 in the first embodiment in the configuration of the first bridging portion and the second bridging portion. In the second embodiment, the first bridging portion includes a first separation bridging member 218a in addition to the first central bridging member 116a. The first separation bridge member 218a is separated from the first axis s in the left-right direction. The first separation bridging member 218a bridges the first through hole A in the front-rear direction, thereby connecting the main body 214 and the first fixed portion 115a. A pair of first separation bridging members 218a are provided on both the left and right sides of the first central bridging member 116a so as to be line symmetric with respect to the first axis s. Similarly, the second bridging portion includes a second separated bridging member 218b in addition to the second central bridging member 116b. The second separation bridging member 218b is separated from the first axis s in the left-right direction. The second separation bridge member 218b bridges the second through hole B in the front-rear direction, thereby connecting the main body 214 and the second fixed portion 115b. A pair of second separating bridge members 218b are provided on both the left and right sides of the second center bridging member 116b so as to be line symmetric with respect to the first axis s. In addition, when not distinguishing the 1st separated bridge member 218a and the 2nd separated bridge member 218b, it calls the separated bridge member 218 only. The fixed portion FP is provided at a position separated from the separation bridge member 218 in the left-right direction, avoiding an extension line in the front-rear direction of the separation bridge member 218.

[Examination of configuration of separation bridging member 218]
By adjusting the separation distance of the separation bridging member 218 from the first axis s, it is possible to adjust the characteristics of the optical scanner 200, specifically, the degree of suppression of the maximum vibration amount in the main body 214. Here, a desirable configuration of the separation bridging member 218 will be considered with the separation interval of the separation bridging member 218 from the first axis s as a variable.

  FIG. 5 shows a result of changing the position of the separation bridging member 218 by simulation under the same condition (outer shape and material) of the structure 210 as that of the optical scanner 200. The horizontal axis in FIG. 5 indicates the separation interval of the separation bridging member 218 from the first axis s. Specifically, a value obtained by dividing La by Lb in FIG. 4 is adopted as the horizontal axis of FIG. La is a distance between the first axis s and the center line in the front-rear direction of the separation bridging member 218. Lb is the distance from the first axis s to the left end of the second through hole B. Since the second through hole B is axisymmetric with respect to the first axis s, the distance from the first axis s to the right end of the second through hole B is also Lb. Further, the first through hole A and the second through hole B are symmetric with respect to the mirror portion 130. For this reason, in the first through hole A, the distance from the first axis s to the left and right ends is also Lb. The vertical axis in FIG. 5 represents the maximum amount of vibration at a position where the amount of displacement in the vertical direction of the main body 214 is maximum during driving. Further, the maximum vibration amount is expressed as a percentage by dividing by the maximum displacement amount in the vertical direction of the mirror unit 130 during driving.

  As apparent from FIG. 5, regardless of the position of the separation bridging member 218, the value of the maximum vibration amount remains at about 20% or less. That is, in addition to the center bridging member 116, the separation bridging member 218 is provided, so that the vibration amount in the main body 214 can be further suppressed (see FIG. 2). More specifically, the maximum vibration amount decreases as the position of the separating bridge member increases from 0%. Then, the maximum vibration amount is reduced to about 10% when the separation bridging member position is around 15%. Thereafter, the maximum amount of vibration decreases as the position of the separation bridging member increases. The maximum amount of vibration is minimized when the separation bridging member position is around 35%. Thereafter, the maximum vibration amount starts to increase as the position of the separation bridging member increases. The maximum vibration amount increases to about 10% when the separation bridging member position is around 55%. Thereafter, the maximum amount of vibration increases with an increase in the position of the separating bridge member.

  Empirically, from the viewpoint of reducing abnormal noise, if the maximum vibration amount of the main body 214 is 10% or less, it is effective. Further, when the maximum vibration amount of the main body 214 is 10% or less, the Q value of the optical scanner 200 is empirically higher than when the maximum vibration amount of the main body 214 is 10% or more. The optical scanner having a high Q value reduces the attenuation of air resistance and the like and can be driven with high efficiency, which contributes to lowering the driving voltage. Therefore, in the optical scanner 200, the separation interval from the first axis s of the separation bridging member 218 is desirably 15% to 55% where the maximum vibration amount is 10% or less. Further, it is more preferable that the separation distance from the first axis s of the separation bridging member 218 is 35% at which the maximum vibration amount is minimized.

<Third Embodiment>
[Configuration of Optical Scanner 300]
3rd Embodiment reflecting the other side surface of this invention is shown. The optical scanner 300 according to the third embodiment differs from the optical scanner 200 according to the second embodiment in the shape of the structure 310. Therefore, in the optical scanner 300, the same components as those in the optical scanner 200 are given the same numbers, and the description thereof is omitted.

  As shown in FIG. 6, the optical scanner 300 includes a structure 310 and a pedestal 120. The structure 310 is different from the structure 210 in the second embodiment in the configuration of the first bridging portion and the second bridging portion. Specifically, in the third embodiment, the first center bridging member 116a and the second center bridging member 116b do not exist. That is, the first bridging portion has only the first separation bridging member 218a. Further, the second bridging portion has only the second separation bridging member 218b.

[Examination of configuration of separation bridging member 218]
As in the second embodiment described above, a desirable configuration of the separation bridging member 218 will be considered with the separation interval of the separation bridging member 218 from the first axis s as a variable.

  FIG. 7 shows a result of changing the position of the separation bridging member 218 by simulation under the same condition (outer shape and material) of the structure 310 as that of the optical scanner 300. The horizontal axis and horizontal axis in FIG. 7 are the same as the vertical axis and horizontal axis in FIG.

  As is apparent from FIG. 7, the maximum vibration amount remains at about 15% or less regardless of the position of the separation bridging member 218. That is, by providing only the separation bridging member 218, the vibration amount in the main body 314 can be further suppressed as compared with the case of being provided with the central bridging member 116 (see FIG. 5). More specifically, the maximum vibration amount decreases as the position of the separating bridge member increases from 0%. Then, the maximum vibration amount is reduced to about 10% when the separation bridging member position is around 15%. Thereafter, the maximum amount of vibration decreases as the position of the separation bridging member increases. The maximum amount of vibration is minimized when the separation bridging member position is around 35%. Thereafter, the maximum vibration amount starts to increase as the position of the separation bridging member increases. The maximum vibration amount increases to about 10% when the position of the separation bridging member is around 65%. Thereafter, the maximum amount of vibration increases with an increase in the position of the separating bridge member.

  Similar to the optical scanner 200 shown in FIG. 5, the separation distance from the first axis s of the separation bridging member 218 is preferably a region where the maximum vibration amount is 10% or less. Specifically, an area of 15% to 65% in which the upper limit value is slightly expanded as compared with the optical scanner 200 shown in FIG. 5 is desirable as the separation interval from the first axis s of the separation bridging member 218. . Further, it is more desirable that the separation distance from the first axis s of the separation bridging member 218 is 35% at which the maximum vibration amount is minimized.

  The present invention is not limited to the embodiments described so far, and various modifications and changes can be made without departing from the spirit of the present invention. An example is described below.

  In the above-described embodiment, the piezoelectric element 117 is used as the drive unit. However, even an optical scanner that employs another driving method such as an electromagnetic driving method using a combination of a magnet and a coil pattern or an electrostatic driving method using an electrostatic force acting between electrode plates is included in the scope of the present invention. .

  In the above-described embodiment, the main body portion extends from the connecting portion with the torsion beam portion to both sides in the left-right direction. In other words, the torsion beam portion is supported at both ends in the left-right direction by the main body portion. However, for example, the main body portion may extend only in any one of the left and right directions from the connecting portion with the torsion beam portion. In other words, the torsion beam portion may be cantilevered in the left-right direction by the main body portion. When the torsion beam part is cantilevered, the drive part provided in the main body part also corresponds to the main body part extending only in one of the left and right directions, and is provided only on one side with respect to the first axis s. .

  In the above-described embodiment, the pedestal 120 is a plate-like member formed in a rectangular shape. However, the pedestal is not limited to this shape. As long as the fixed part of the structure can be fixed, the pedestal may have any shape. For example, a pair of rod-like members having the same width in the front-rear direction as the fixed portion and the longitudinal direction parallel to the left-right direction may be used as the pedestal.

  In the embodiment described above, the optical scanner is driven at a resonant frequency. However, the present invention can also be applied to an optical scanner that is not resonantly driven. This is because, even in an optical scanner that is not resonantly driven, vibration is applied to the structure for driving, so that the problem of vibration of the structure also occurs.

100, 200, 300 Optical scanner 110, 210, 310 Structure 111 Oscillating part 112a First torsion beam part 112b Second torsion beam part 114 Main body part 115a First fixed part 115b Second fixed part 116a First central bridge Member 116b Second central bridging member 117 Piezoelectric element 120 Base 130 Mirror part 218a First spacing bridging member 218b Second spacing bridging member

Claims (5)

A mirror portion having a reflecting surface for reflecting incident light and configured to be swingable about a first axis;
A first torsion beam portion extending in parallel with the first axis from one end of the mirror portion;
A second torsion beam part extending from the other end of the mirror part in a direction parallel to the first axis and opposite to the first torsion beam part;
A main body connected to ends of the first torsion beam part and the second torsion beam part and extending away from the mirror part and intersecting the first axis;
A planar structure having
A pedestal to which a part of the structure is fixed;
A drive unit that is provided in the main body unit and can vibrate the structure by applying a drive voltage, and can swing the mirror portion around the first axis;
The body part is
A first through hole provided at a position farther from the mirror part than an end of the first torsion beam part in a direction parallel to the first axis, and extending in a direction intersecting the first axis;
A second through hole provided at a position farther from the mirror part than an end of the second torsion beam part in a direction parallel to the first axis, and extending in a direction intersecting the first axis;
A first fixed portion provided at a position farther from the mirror part than the first through hole in a direction parallel to the first axis, and fixed to the pedestal;
A second fixed portion that is provided at a position farther from the mirror portion than the second through hole in a direction parallel to the first axis, and is fixed to the pedestal;
A first bridging portion that extends in a direction along the first axis and bridges the first through-hole to connect the main body and the first fixed portion;
A second bridging portion that extends in a direction along the first axis and connects the main body portion and the second fixed portion by bridging the second through hole;
Only including,
The first bridging portion is spaced apart from the first axis in a direction intersecting the first axis, and connects the main body portion and the first fixed portion by bridging the first through hole. Having a spacing bridge member;
The second bridging portion is separated from the first axis in a direction intersecting the first axis, and the second bridging portion bridges the second through hole to connect the main body portion and the second fixed portion. Having a spacing bridge member;
An optical scanner characterized by that. The first bridging portion includes the first axis, and includes a first central bridging member that connects the main body portion and the first fixed portion by bridging the first through hole.
The second bridging portion includes the first axis, and has a second central bridging member that connects the main body portion and the second fixed portion by bridging the second through hole.
The optical scanner according to claim 1. The main body is formed symmetrically with respect to the first axis.
A pair of the first separation bridge member and the second separation bridge member are provided so as to be line symmetric with respect to the first axis, respectively.
The optical scanner according to claim 1 or 2 . In the direction intersecting the first axis, the first spacing bridge member has a spacing distance from the first axis of 15 to 65% of the distance between the first axis and the end of the first through hole. Provided at the position
In the direction crossing the first axis, the second spacing bridge portion has a spacing distance from the first axis of 15 to 65% of the distance between the first axis and the end of the second through hole. Provided at a position,
The optical scanner according to claim 1 . The first fixed portion and the second fixed portion are fixed to the base at a plurality of fixing portions,
The plurality of fixed portions are provided at positions separated from the first bridging portion and the second bridging portion in a direction intersecting the first axis.
The optical scanner according to any one of claims 1-4.

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