JP2018128700A - Drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an appropriate driving force by a simple configuration.SOLUTION: A drive device (101) comprises: a first base unit (110) connected with a driven unit; a coil (300) arranged on the first base unit; a first magnet (710) arranged so as to enclose a portion of the outer circumference of the coil; a second magnet (720) arranged so as to enclose a portion of the outer circumference of the coil that is not enclosed by the first magnet; a first middle yoke (810) provided on the first magnet; and a second middle yoke (820) provided on the second magnet. The first magnet is smaller than the second magnet, the first middle yoke is arranged so that the distance from the coil to the second middle yoke in a direction in which the driven unit is arranged is greater than the distance from the coil to the first middle yoke in a different direction as seen from the coil.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technical field of a driving device such as a MEMS scanner that drives a driven object such as a mirror.

  For example, in various technical fields such as a display, a printing apparatus, precision measurement, precision processing, and information recording / reproduction, research on a MEMS (Micro Electro Mechanical System) device manufactured by a semiconductor process technology is actively advanced. As such a MEMS device, for example, a display field in which light incident from a light source is scanned with respect to a predetermined screen region to embody an image, or light reflected by scanning light with respect to a predetermined screen region. In the scanning field where light is received and image information is read, a micro-structured mirror driving device (optical scanner or MEMS scanner) has attracted attention.

  In a mirror driving device, a configuration in which a mirror is driven using a coil and a magnet is generally used. In this case, a force in the rotational direction is applied to the mirror by the interaction between the magnetic field generated by passing a current through the coil and the magnetic field of the magnet, and as a result, the mirror is rotated (see, for example, Patent Document 1). ).

JP-A-11-231252

  In Patent Document 1 described above, a magnetic field is generated by arranging two magnets on the side of the coil. However, for example, when the MEMS scanner and the magnet are arranged so as to overlap with each other in a plane, the arrangement space of the magnet is limited in order to secure the drive area of the MEMS scanner. On the other hand, it is desirable for the magnet to impart a well-balanced magnetic field to the MEMS scanner. For this reason, it is not easy to properly lay out the magnets, and as a result, the apparatus configuration may be complicated and enlarged.

  Examples of problems to be solved by the present invention include the above. It is an object of the present invention to provide a driving device that can realize an appropriate driving force with an easy configuration.

  In order to solve the above-described problem, the driving device is disposed so as to surround a first base portion connected to the driven portion, a coil disposed on the first base portion, and a part of an outer periphery of the coil. A first magnet, a second magnet disposed to surround a portion of the outer periphery of the coil and not surrounded by the first magnet, and a first magnet provided on the first magnet. A middle yoke and a second middle yoke provided on the second magnet, wherein the first magnet is smaller than the second magnet, and the first middle yoke has the driven portion from the coil. It arrange | positions so that the distance from the said coil to the said 1st middle yoke in the direction different from the said direction may become near from the distance to the said 2nd middle yoke in the arrange | positioned direction.

It is a top view which shows the structure at the time of seeing the MEMS scanner which concerns on an Example from the front side. It is a top view which shows the structure at the time of seeing the MEMS scanner which concerns on an Example from the back side. It is sectional drawing which shows the laminated structure of the MEMS scanner which concerns on an Example. It is a side view which shows notionally the aspect of operation | movement of the MEMS scanner which concerns on an Example. It is a top view which shows arrangement | positioning of the magnet and middle yoke with respect to the MEMS scanner which concerns on an Example. It is sectional drawing which shows the structure of the member which applies a magnetic field to the MEMS scanner which concerns on an Example. It is a conceptual diagram which shows the positional relationship of the member which applies a magnetic field to a coil. It is a top view which shows arrangement | positioning of the magnet and middle yoke with respect to the MEMS scanner which concerns on a 1st comparative example. It is a top view which shows arrangement | positioning of the magnet and middle yoke with respect to the MEMS scanner which concerns on a 2nd comparative example. It is a conceptual diagram explaining the presence or absence of interference with the middle yoke at the time of V-axis drive.

  Hereinafter, embodiments of the drive device will be described in order.

<1>
The driving device according to the present embodiment includes a first base portion, a second base portion, an elastic portion that connects the first base portion and the second base portion, and a coil disposed on the first base portion. A first magnet disposed on one side of the coil, a second magnet disposed on the opposite side of the first magnet when viewed from the coil, and a surface of the first magnet facing the coil And a second middle yoke provided on a surface of the second magnet facing the coil, the first magnet being smaller than the second magnet, The first middle yoke is disposed closer to the coil than the second middle yoke.

  According to the driving device of the present embodiment, the first base portion and the second base portion are directly or indirectly coupled (in other words, connected) by an elastic portion (for example, a spring portion described later) having elasticity. ) Here, it is preferable that the rigidity of the elastic part is lower than the rigidity of one or both of the first base part and the second base part due to the elasticity of the elastic part. In other words, it is preferable that the elastic portion is relatively easily deformed relative to both or one of the first base portion and the second base portion. In other words, it is preferable that both or one of the first base portion and the second base portion is relatively difficult to deform while the elastic portion is relatively easily deformed.

  A coil is disposed on the first base portion. For example, the first base portion is configured as a frame-like frame having an opening portion, and a coil is wound around the opening portion. A first magnet is disposed on one side of the coil, and a second magnet is disposed on the opposite side of the coil from the first magnet. That is, two magnets are arranged so as to sandwich the coil. For this reason, the magnetic field resulting from two magnets generate | occur | produces around a coil. Therefore, a Lorentz force on the coil can be generated by supplying a predetermined control current to the coil.

  The surface on the side facing the coil of the first magnet and the surface on the side facing the coil of the second magnet typically have different polarities. Specifically, when the surface of the first magnet facing the coil is an N pole, the surface of the second magnet facing the coil is an S pole. Alternatively, when the surface of the first magnet facing the coil is the south pole, the surface of the second magnet facing the coil is the north pole. In this case, when a control current is passed through the coil, Lorentz forces having different directions are generated on the first magnet side and the second magnet side of the coil. Such Lorentz force acts as a driving force for rotating the first base portion on which the coil is disposed. Such a driving force may be transmitted to the second base portion via an elastic portion connected to the first base portion.

  A first middle yoke is provided on the surface facing the coil of the first magnet. A second middle yoke is provided on the surface facing the coil of the second magnet. It is preferable that the first middle yoke and the second middle yoke include a soft magnetic material having a high relative permeability such as pure iron, permalloy, silicon iron, sendust, and the like. According to such a 1st middle yoke and a 2nd middle yoke, the magnetic flux which generate | occur | produces from a 1st magnet and a 2nd magnet can be suitably converged with respect to a coil. Therefore, the driving force applied to the coil can be improved.

  Here, in the present embodiment, in particular, the first magnet is configured to be smaller than the second magnet. More specifically, for example, the coil-side surface area of the first magnet is configured to be narrower than the coil-side surface area of the second magnet. In addition, the first middle yoke is disposed closer to the coil than the second middle yoke. That is, the middle yoke provided in the smaller magnet is disposed closer to the coil than the middle yoke provided in the larger magnet.

  According to the configuration described above, the magnetic field that the first magnet gives to the coil is smaller than the magnetic field that the second magnet gives to the coil because the first magnet is smaller than the second magnet. However, since the first middle yoke provided on the first magnet is closer to the coil than the second middle yoke provided on the second magnet, the first middle yoke focuses the magnetic flux on the coil more than the second middle yoke. High effect. Therefore, the difference in the magnitude of the magnetic field due to the size of the first magnet and the second magnet is offset by the difference in the magnetic flux focusing effect due to the difference in the distance between the first middle yoke and the second middle yoke. A balanced magnetic field can be applied to the coil. Thereby, the Lorentz force generated in the coil can be brought close to a couple, and more suitable driving of the first base portion can be realized.

  A well-balanced magnetic field can be realized even if the sizes of the first and second magnets are the same, but depending on the space where the magnets can be placed, it is difficult to align the sizes of the two magnets. There is also. In particular, in the aspect in which the second base portion is connected to the first base portion provided with the coil as in the present embodiment, there is a high possibility that each member is required to be arranged asymmetrically with respect to the coil. .

  However, in the present embodiment, as described above, even if there is a difference in size between the first magnet and the second magnet, the distance between the first middle yoke and the second middle yoke and the coil is adjusted. An appropriate magnetic field can be applied to the coil. Therefore, an appropriate driving force can be applied to the coil, and a suitable driving can be realized.

<2>
In another aspect of the driving apparatus of the present embodiment, the second magnet is disposed on the second base portion side when viewed from the coil.

  According to this aspect, the 2nd magnet which is a larger magnet is arrange | positioned at the 2nd base part side seeing from a coil. In other words, the smaller magnet is disposed on the side opposite to the second base portion when viewed from the coil.

  Here, on the side of the second base portion where the second magnet is provided, there is necessarily a space for arranging the second base portion. Therefore, for example, if a space overlapping the second base portion in plan is used, it is easy to dispose a relatively large second magnet.

  On the other hand, considering that the second base portion is also driven by the driving force transmitted from the first drive portion, it is required to secure an area for driving the second base portion. However, a member that is desired to be disposed at a position close to the coil (in other words, a position close to the second base portion) like the middle yoke may interfere with driving of the second base portion.

  However, the second middle yoke provided in the second magnet has a larger distance from the coil than the first middle yoke. Therefore, it is easy to arrange the second middle yoke at a distance that does not interfere with the drive region of the second base portion, for example.

<3>
As described above, in the aspect in which the second magnet is disposed on the second base portion side, the first magnet is provided along the first side of the first base portion on the side not facing the second base portion. A first portion and a second portion provided along a second side adjacent to the first side, and the second magnet includes the second base of the first base portion. A third portion provided along a third side on the side facing the part, and a fourth portion provided along a fourth side adjacent to the third side, The first portion is smaller than the third portion, and the portion of the first middle yoke provided on the surface of the first portion is provided on the surface of the third portion of the second middle yoke. You may arrange | position in the position near the said coil rather than the provided part.

  In this case, the first part of the first magnet is provided smaller than the third part of the second magnet. Specifically, the first portion provided along the first side of the first base part (that is, the side that does not face the second base part) is the third side of the first base part (that is, the side that is not opposed to the second base part). , Provided on the side opposite to the second base portion) and smaller than the third portion. Accordingly, the second magnet disposed on the second base portion side is larger than the first magnet. In addition, about the magnitude | size of the other 2nd part and the 4th part, although it is typically set as the substantially same magnitude | size, it does not specifically limit.

  On the other hand, the portion of the first middle yoke provided on the surface of the first portion is disposed closer to the coil than the portion of the second middle yoke provided on the surface of the third portion. . Therefore, the difference in the magnitude of the magnetic field caused by the magnitudes of the first part and the third part is the difference in the magnetic flux focusing effect caused by the difference in the distance between the middle yokes provided in the first part and the third part. More offset. Therefore, a balanced magnetic field can be applied to the coil.

<4>
In another aspect of the driving apparatus of the present embodiment, the first middle yoke and the second middle yoke are disposed so as not to overlap the first base portion and the second base portion in plan view. .

  According to this aspect, the first middle yoke and the second middle yoke can be prevented from obstructing the driving of the first base portion and the second base portion. In other words, the first middle yoke and the second middle yoke are arranged so as not to overlap the first base portion and the second base portion in a plan view, but in terms of height, the first base portion and the second middle yoke are arranged. 2 Can be arranged close to the base part. Therefore, the magnetic flux focusing function by the first middle yoke and the second middle yoke can be effectively exhibited.

<5>
In another aspect of the drive device of the present embodiment, the drive device further includes a yoke inserted through the opening portion of the first base portion.

  According to this aspect, the magnetic flux can be focused on the coil by the yoke inserted through the opening portion of the first base portion. Therefore, the Lorentz force generated by passing a control current through the coil can be increased. That is, the driving force applied by the coil can be increased. As with the first middle yoke and the second middle yoke, the yoke is preferably configured to include a soft magnetic material having a high relative permeability such as pure iron, permalloy, silicon iron, sendust, and the like.

  In order to enhance the magnetic flux focusing effect by the yoke, it is preferable that the distance between the yoke and the coil is small. For this reason, it is preferable that the yoke is enlarged in a range that does not hinder driving of the first base portion on which the coil is arranged. Moreover, it is preferable that the cross section of a yoke is a shape close | similar to the shape of the opening part of a 1st base part.

  Furthermore, the yoke is inserted, for example, from the lower side to the upper side of the first base portion. In order to enhance the magnetic flux focusing effect by the yoke, it is preferable that the yoke is configured to extend to some extent upward. For this reason, it is preferable that a yoke is comprised long in the range which does not prevent the drive of the 1st base part in which the coil is arrange | positioned.

<6>
In another aspect of the driving device of the present embodiment, the driving device further includes a driven portion supported by the second base portion.

  According to this aspect, the second base portion supports the driven portion configured as, for example, a mirror. At this time, the second base portion supports the driven portion so that the driven portion can be driven (for example, rotatable or movable). More specifically, for example, the second base portion and the driven portion are connected by an elastic portion having elasticity, so that the second base portion supports the first driven portion in a drivable manner. Also good.

  According to the drive device having such a configuration, the driven part can be suitably driven (for example, rotated or moved). That is, according to the drive device having such a configuration, the driven part can be driven (for example, rotated or moved) suitably. Specifically, for example, when the first base portion moves, the second base portion connected to the first base portion via the elastic portion also moves along with the movement of the first base portion. . When the second base portion moves, the driven portion supported by the second base portion also moves along with the movement of the second base portion. As a result, the driven part can be driven suitably.

  Hereinafter, embodiments of the drive device of the present invention will be described with reference to the drawings. In the following, an example in which the driving device is applied to a MEMS scanner will be described. However, it goes without saying that the drive device of the present invention may be applied to any drive device other than the MEMS scanner.

(1) Basic Configuration First, the configuration of the MEMS scanner 101 according to the present embodiment will be described with reference to FIGS. FIG. 1 is a plan view showing the configuration when the MEMS scanner 101 according to the embodiment is viewed from the front side, and FIG. 2 shows the configuration when the MEMS scanner 101 according to the embodiment is viewed from the back side. It is a top view. FIG. 3 is a cross-sectional view illustrating a stacked structure of the MEMS scanner 101 according to the embodiment.

  As shown in FIGS. 1 and 2, the MEMS scanner 101 according to the present embodiment includes a first base 110, a second base 120, V torsion bars 150 and 160, a spring part 210, a wiring spring part 220, and the like. The coil 300, the mirror 400, and the H torsion bar 450 are provided.

  The 1st base 110 has a frame shape provided with a space (opening part) inside. That is, the first base 110 has two sides extending in the Y-axis direction in the drawing and two sides extending in the X-axis direction (that is, a direction orthogonal to the Y-axis direction) in the drawing, and Y It has a frame shape having a gap surrounded by two sides extending in the axial direction and two sides extending in the X-axis direction. In the example shown in FIGS. 1 and 2, the first base 110 has a square shape, but is not limited thereto. For example, the first base 110 has other shapes (for example, a rectangular shape such as a rectangle). Or a circular shape or the like. Further, the first base is not limited to the frame shape.

  A coil 300 is disposed on the first base. The coil 300 is a plurality of windings made of, for example, a material having relatively high conductivity (for example, gold, copper, etc.). In the present embodiment, the coil 300 has a square shape along the first base 110. However, the coil 300 may have any shape (for example, a rectangle, a rhombus, a parallelogram, a circle, an ellipse, or any other loop shape).

  The coil 300 is supplied with a control current from a power supply via a power supply terminal (not shown). Note that the power source may be a power source provided in the MEMS scanner 101 itself, or may be a power source prepared outside the MEMS scanner 101. A magnet (not shown) is arranged around the coil 300, and a rotational force is applied by the interaction between the magnetic field generated by passing a control current through the coil 300 and the magnetic field of the magnet. The first base 110 provided with the coil 300 is rotated in a direction corresponding to the direction of the magnetic field and the control current.

  Similar to the first base portion 110, the second base portion 120 has a frame shape with a gap inside. A mirror 400 is disposed in the gap of the second base 120. The mirror 400 is arranged to be suspended or supported by the H torsion bar 450.

  The H torsion bar 450 is a member having elasticity such as a spring made of silicon, copper alloy, iron-based alloy, other metal, resin, or the like. The H torsion bar 450 is arranged to extend in the Y-axis direction in FIG. In other words, the H torsion bar 450 has a shape having a long side extending in the Y-axis direction and a short side extending in the X-axis direction. One end of the H torsion bar 450 is connected to the second base 110. The other end of the H torsion bar 450 is connected to the mirror 400. For this reason, the mirror 400 can rotate about the axis along the Y-axis direction as a rotation axis by the elasticity of the H torsion bar 450. The mirror 400 is a specific example of “driven part”.

  The first base 110 and the second base 120 are connected to each other by a spring part 210. The spring part 210 is a specific example of the “elastic part” and has a function of transmitting the driving force obtained from the coil 300 in the first base 110 to the second base 120. In addition, a wiring spring part 220 is provided between the first base 110 and the second base 120. The wiring spring part 220 is provided to realize electrical connection between the first base 110 and the second base 120. Specifically, a connection wiring 225 for connecting the coil 300 of the first base 110 and the wiring 500 of the second base 120 is arranged in the wiring spring part 220.

  The first base 110 and the second base 120 are fixed to a substrate or a support member (not shown) via V torsion bars 150 and 160 (in other words, fixed inside the MEMS scanner 101 system). Have been). Alternatively, the first base 110 may be suspended by a suspension (not shown) or the like.

  As shown in FIG. 3, the MEMS scanner 101 according to the present embodiment is configured by a laminated structure of a support layer 10, an active layer 20, a BOX layer 30 and a metal layer 40. However, a laminated structure including other layers may be employed.

Each of the support layer 10 and the active layer 20 includes, for example, silicon. The BOX layer 30 is made of, for example, an oxide film such as SiO ₂ and is disposed between the support layer 10 and the active layer 20. The BOX layer 30 insulates the support layer 10 and the active layer 20. The metal layer 40 includes, for example, a metal having high conductivity and is disposed on the active layer 20. The metal layer 40 constitutes the coil 300 in the first base 110, the wiring 500 in the second base 120, the connection wiring 225 in the wiring spring portion 220, and the like.

  The support layer 10 is formed so as to extend from the first base 110 to the spring portion 210 and the second base 120 (specifically, refer to FIG. 2). On the other hand, the active layer 20, the BOX layer 30, and the metal layer 40 are formed on the first base 110 and the second base 120, but are not formed on the spring portion 210. In other words, the spring part 210 is constituted only by the support layer 20. Further, the spring part 210 is configured integrally with the support layer 10 of the first base 110 and the support layer of the second base 120. The active layer 20 is not formed on the spring part 210, but the active layer 20 is formed on the wiring spring part 220 (see FIG. 1). For this reason, electrical connection between the first base 110 and the second base 120 can be realized.

(2) Operation of MEMS Scanner Next, the operation of the MEMS scanner 101 according to the present embodiment will be described with reference to FIG. FIG. 4 is a side view conceptually showing an operation mode of the MEMS scanner according to the embodiment. In FIG. 4 and subsequent figures, for convenience of explanation, detailed members constituting the MEMS scanner 101 described in FIG. 1 to FIG.

  As shown in FIG. 4A, in the MEMS scanner 101 according to the present embodiment, an external magnetic field is applied to the coil 300 from the upper right direction to the lower right direction in the drawing. The external magnetic field is applied by a magnet described later. However, the direction of the magnetic field here is an example, and the magnetic field may be applied in another direction.

  4A and 4B, a control current is supplied to the coil 300 when the MEMS scanner 101 according to this embodiment operates. Then, Lorentz force is generated due to electromagnetic interaction between a magnetic field generated by supplying a control current to the coil 300 and an external magnetic field. Specifically, a reverse Lorentz force is generated at one end and the other end of the coil 300.

  When the Lorentz force is generated, the first base provided with the coil 300 is driven. The driving force of the first base 110 is transmitted to the second base 120 via the spring part 210. Therefore, the second base 120 is also driven in conjunction with the driving of the first base 110. The driving force of the second base is also transmitted to the mirror 400 via the H torsion bar. Therefore, the mirror 400 is also driven in conjunction with the driving of the second base 120. As described above, when the Lorentz force is generated in the coil 300, each of the first base 110, the second base 120, and the mirror 400 is driven.

  Here, when the frequency of the control current supplied to the coil 300 is DC to several hundred Hz, the MEMS scanner 101 rotates around the X axis. Specifically, the MEMS scanner 101 rotates about the V torsion bars 150 and 160 as rotation axes. As a result, the mirror 400 also rotates about the X axis as a rotation axis, and so-called vertical scanning is executed.

  As shown in FIG. 4C, when the control current supplied to the coil 300 has a frequency corresponding to the natural resonance mode, the MEMS scanner 101 rotates around the Y axis. Specifically, each of the first base 110 and the second base 120 of the MEMS scanner 101 rotates about different axes along the Y axis. As a result, the mirror 400 also rotates about the Y axis as a rotation axis, and so-called lateral scanning is executed.

  At the time of driving described above, the Lorentz force generated in the coil 300 is preferably a couple. In particular, in driving using the Y axis as the rotation axis, the rotation center of the coil 300 is determined only by the dimensions, hardness, and weight of each part of the structure, and is easily affected when an external force is applied. If the Lorentz force generated in the coil 300 deviates from the couple, other movements (for example, the movement in which the coil 300 translates) are mixed with the resonance movement, which hinders smooth resonance movement.

  In order to make the Lorentz force generated in the coil 300 close to the couple, the magnetic field applied to the coil 300 is horizontal, and the strengths on the left and right sides of the coil 300 (that is, two regions where the Lorentz force is generated) are approximately the same. It is preferable that

(3) Arrangement of Magnet and Yoke Next, the configuration of the magnet and the yoke for generating a magnetic field for the MEMS scanner 101 according to the present embodiment will be described with reference to FIGS. FIG. 5 is a plan view showing the arrangement of the magnets and the middle yoke with respect to the MEMS scanner according to the embodiment. FIG. 6 is a cross-sectional view illustrating a configuration of a member that applies a magnetic field to the MEMS scanner according to the embodiment. FIG. 7 is a conceptual diagram showing the positional relationship of members that apply a magnetic field to the coil.

  In FIG. 5, according to the MEMS scanner 101 according to the present embodiment, the first magnet 710 is disposed on one side (upper right in the drawing) of the coil 300. The first magnet 710 has a dogleg shape so as to extend along two sides of the first base 110 on which the coil 300 is provided. A first middle yoke 810 is provided on the surface of the first magnet 710 facing the coil 300.

  A second magnet 720 is arranged on the other side of the coil 300 (lower left in the figure). The second magnet 720 has a dogleg shape along two sides of the first base 110 on which the coil 300 is provided (specifically, two sides different from the two sides along which the first magnet 710 is along). Yes. A second middle yoke 820 is provided on the surface of the second magnet 720 facing the coil 300. The second magnet 720 is disposed using a relatively wide space from the lower side of the second base 120 to the lower side of the V torsion bar 160. That is, the second magnet 720 is configured as a larger magnet than the first magnet 710. Further, the second middle yoke 820 does not cover the entire surface of the second magnet 720 but is provided at a position where it does not overlap the second base in a planar manner.

  In FIG. 6, the coil 300 is inserted with a yoke 600 extending upward from the lower yoke 650. A third magnet 730 and a fourth magnet 740 are disposed above the MEMS scanner 101. A third middle yoke 830 is provided on the surface of the third magnet 730 facing the coil 300. A fourth middle yoke 840 is provided on the surface of the fourth magnet 740 facing the coil 300.

  Here, each of the yoke 600, the lower yoke 650, the first middle yoke 810, the second middle yoke 820, the third middle yoke 830, and the fourth middle yoke 840 includes, for example, pure iron, permalloy, silicon iron, sendust, and the like. And a soft magnetic material having a high relative magnetic permeability. According to each of these yokes, the magnetic flux generated by the first magnet 710, the second magnet 720, the third magnet 730, and the fourth magnet 740 can be suitably focused on and parallel to the coil 300. . As a result, the driving force applied to the coil 300 can be improved.

  In FIG. 7, in the MEMS scanner 101 according to the present embodiment, in particular, the distance L1 between the portion of the first middle yoke 810 along the right side of the coil 300 in the drawing and the yoke 600 is the second middle yoke 820. The coil 300 is configured to be smaller than the distance L2 between the portion along the left side in the drawing and the yoke 600. For this reason, the magnetic flux focusing function for the coil 300 of the first middle yoke 810 is higher than that of the second middle yoke 820. Therefore, the difference in magnetic field strength due to the difference in size between the first magnet 710 and the second magnet 720 is offset by the difference in magnetic flux focusing function due to the difference in distance between the first middle yoke 810 and the second middle yoke 820. The In other words, the distances L1 and L2 between the first middle yoke 810 and the second middle yoke 820 and the yoke 600 are values that can cancel the difference in magnetic field strength between the first magnet 710 and the second magnet 720. It only needs to be adjusted.

  As a result, a well-balanced magnetic field is applied to the coil 300. Therefore, the Lorentz force generated in the coil 300 at the time of driving can be brought close to the couple, and more preferable driving can be realized.

(4) Comparison with Comparative Example Next, a comparison between the MEMS scanner 101b according to the first comparative example and the MEMS scanner 101c according to the second comparative example described with reference to FIGS. The advantages of the MEMS scanner 101 will be specifically described. FIG. 8 is a plan view showing the arrangement of magnets and middle yokes for the MEMS scanner according to the first comparative example. FIG. 9 is a plan view showing the arrangement of magnets and middle yokes for the MEMS scanner according to the second comparative example. FIG. 10 is a conceptual diagram illustrating the presence or absence of interference with the middle yoke during V-axis driving.

  In FIG. 8, the first magnet 710b and the first middle yoke 810b according to the first comparative example are the same as the first magnet 710 and the first middle yoke 810 (see FIG. 5) of the MEMS scanner 101 according to the present embodiment. It is provided as. On the other hand, the second magnet 720b and the second middle yoke 820b according to the first comparative example are provided as being smaller than the second magnet 720 and the second middle yoke 820 (see FIG. 5) of the MEMS scanner 101 according to the present embodiment. It has been. Specifically, the first magnet 710b and the second magnet 720b according to the first comparative example have the same size and are configured to apply an equivalent magnetic field to the coil 300.

  However, in the first comparative example, since the size of the second magnet 720 is smaller than that in the present embodiment, the driving efficiency is deteriorated. Specifically, since the empty space on the left side of the second base 120 cannot be effectively used, the magnetic field applied to the coil 300 is weakened accordingly, and the Lorentz generated in the coil 300 is also reduced.

  In FIG. 9, the first magnet 710c and the first middle yoke 810c according to the second comparative example are larger than the first magnet 710 and the first middle yoke 810 (see FIG. 5) of the MEMS scanner 101 according to the present embodiment. It is provided as a thing. On the other hand, the second magnet 720b according to the first comparative example is provided as the same as the second magnet 720 of the MEMS scanner 101 according to the present embodiment. However, the second middle yoke 820 according to the second embodiment is not partially provided like the second middle yoke 820 according to the present embodiment, but covers the entire surface of the second magnet 720 on the coil 300 side. It is provided as follows. Accordingly, in the second comparative example, as in the first comparative example described above, the first magnet 710c and the second magnet 720c have the same size and apply the same magnetic field to the coil 300. It is configured as.

  However, in the second comparative example, since the size of the first magnet 710 is larger than that in the present embodiment, the first comparative example has popped out of the chip. For this reason, the size of the device including the magnetic circuit is increased, resulting in an increase in the size of the apparatus.

  In FIG. 10A, in the first comparative example and the second comparative example, the second middle yoke 820 is further disposed at a position overlapping the second base 120 in a plane. Therefore, for example, when the MEMS scanner 101b or 101c drives with the V axis (X axis) as the rotation axis, the second base 120 and the second middle yoke 820 interfere with each other. As a method of avoiding such interference, for example, a method of disposing the second middle yoke 820 at a position away from the second base 120 is conceivable. However, the magnetic flux focusing function by the second middle yoke 820 is reduced accordingly. .

  On the other hand, in FIG. 10B, according to the present embodiment, the second middle yoke 820 is not disposed at a position overlapping the second base 120 in a plan view. Therefore, for example, even when the MEMS scanner 101 is driven with the V axis (X axis) as the rotation axis, it is possible to avoid the interference between the second base 120 and the second middle yoke 820.

  As described above, according to the MEMS scanner 101 according to the present embodiment, a plurality of magnets and yokes are arranged in a manner that can avoid interference with the MEMS scanner 101 during driving, A well-balanced magnetic field is applied. Therefore, suitable driving of the MEMS scanner 101 is realized.

  The MEMS scanner 101 according to each embodiment described above can be applied to various electronic devices such as a head-up display, a head-mounted display, a laser scanner, a laser printer, and a scanning drive device. it can. Therefore, these electronic devices are also included in the scope of the present invention.

  Further, the present invention can be appropriately changed without departing from the gist or concept of the present invention that can be read from the claims and the entire specification, and a drive device that includes such a change is also included in the technical concept of the present invention. It is.

DESCRIPTION OF SYMBOLS 10 Support layer 20 Active layer 30 BOX layer 40 Metal layer 101 MEMS scanner 110 1st base 120 2nd base 150,160 V torsion bar 210 Spring part 220 Wiring spring part 225 Connection wiring 300 Coil 400 Mirror 450 H Torsion bar 500 Wiring 600 Yoke 650 Lower yoke 710 1st magnet 720 2nd magnet 730 3rd magnet 740 4th magnet 810 1st middle yoke 820 2nd middle yoke 830 3rd middle yoke 840 4th middle yoke

Claims (1)

A first base connected to the driven part;
A coil disposed on the first base portion;
A first magnet disposed so as to surround a part of the outer periphery of the coil;
A second magnet arranged to surround a portion of the outer periphery of the coil that is not surrounded by the first magnet;
A first middle yoke provided on the first magnet;
A second middle yoke provided on the second magnet,
The first magnet is smaller than the second magnet,
The first middle yoke has a distance from the coil to the first middle yoke in a direction different from the direction from a distance from the coil to the second middle yoke in a direction in which the driven portion is disposed. Are arranged so as to be close to each other.