JP2023095943A - Drive device - Google Patents

Abstract

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 driving devices such as MEMS scanners that drive driven objects such as mirrors.

For example, in various technical fields such as displays, printing devices, precision measurement, precision processing, and information recording/reproducing, researches on MEMS (Micro Electro Mechanical System) devices manufactured by semiconductor process technology are being actively pursued. Such a MEMS device may be used, for example, in the display field in which an image is realized by scanning a predetermined screen area with light incident from a light source, or in the light reflected by scanning a predetermined screen area. In the field of scanning for reading image information by receiving light, minute-structured mirror driving devices (optical scanners or MEMS scanners) are attracting attention.

A mirror driving device generally has a configuration in which a coil and a magnet are used to drive a mirror. In this case, the interaction between the magnetic field generated by the current flowing through the coil and the magnetic field of the magnet applies a rotational force to the mirror, and as a result, the mirror is rotated (see, for example, Patent Document 1). ).

JP-A-11-231252

In Patent Literature 1 mentioned above, a magnetic field is generated by arranging two magnets on the sides of the coil. However, for example, when the MEMS scanner and the magnet are arranged so as to overlap each other in a plane, the space for arranging the magnet is limited in order to secure the driving area of the MEMS scanner. On the other hand, it is desirable for the magnet to provide a well-balanced magnetic field to the MEMS scanner. For this reason, it is not easy to lay out the magnets appropriately, and as a result, there is a risk of complicating the device configuration and increasing the size.

Examples of the problems to be solved by the present invention are as described above. SUMMARY OF THE INVENTION An object of the present invention is to provide a driving device capable of achieving an appropriate driving force with a simple configuration.

In order to solve the above problems, a driving device includes a first base portion connected to a driven portion, a coil arranged on the first base portion, and a coil arranged to surround a part of the outer circumference of the coil. a first magnet, a second magnet disposed so as to surround a part of the outer periphery of the coil that is 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 extends from the coil to the driven portion. The coils are arranged so that the distance from the coil to the first middle yoke in a direction different from the direction is shorter than the distance to the second middle yoke in the direction in which they are arranged.

FIG. 2 is a plan view showing the configuration of the MEMS scanner according to the embodiment when viewed from the front side; FIG. 3 is a plan view showing the configuration of the MEMS scanner according to the embodiment when viewed from the back side; FIG. 3 is a cross-sectional view showing a laminated structure of the MEMS scanner according to the example; FIG. 4 is a side view conceptually showing the mode of operation of the MEMS scanner according to the example. FIG. 4 is a plan view showing the arrangement of magnets and middle yokes for the MEMS scanner according to the example; FIG. 4 is a cross-sectional view showing the configuration of a member that applies a magnetic field to the MEMS scanner according to the example; FIG. 4 is a conceptual diagram showing the positional relationship of members that apply magnetic fields to coils. FIG. 10 is a plan view showing the arrangement of magnets and middle yokes for the MEMS scanner according to the first comparative example; FIG. 11 is a plan view showing the arrangement of magnets and middle yokes for a MEMS scanner according to a second comparative example; FIG. 5 is a conceptual diagram for explaining presence/absence of interference with a middle yoke during V-axis driving;

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

<1>
The drive device of this embodiment includes a first base portion, a second base portion, an elastic portion connecting the first base portion and the second base portion, and a coil disposed on the first base portion. and a first magnet arranged on one side of the coil, a second magnet arranged on the side opposite to 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, wherein the first magnet is smaller than the second magnet and the second magnet The first middle yoke is arranged at a position closer to the coil than the second middle yoke.

According to the drive device of the present embodiment, the first base portion and the second base portion are directly or indirectly connected (in other words, connected ). Here, due to the elasticity of the elastic portion, the rigidity of the elastic portion is preferably lower than the rigidity of either or both of the first base portion and the second base portion. In other words, it is preferable that the elastic portion is relatively easier to deform than both or one of the first base portion and the second base portion. Further, in other words, it is preferable that both or one of the first base portion and the second base portion is relatively hard to deform while the elastic portion is relatively easy to deform.

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

The surface of the first magnet facing the coil and the surface of the second magnet facing the coil typically have different polarities. Specifically, when the surface of the first magnet facing the coil is the north pole, the surface of the second magnet facing the coil is the south pole. Alternatively, if 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 with 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 rotationally moving the first base portion on which the coil is arranged. Incidentally, such driving force may be transmitted to the second base portion via the elastic portion connected to the first base portion.

A first middle yoke is provided on the surface of the first magnet facing the coil. A second middle yoke is provided on the surface of the second magnet facing the coil. The first middle yoke and the second middle yoke preferably contain a soft magnetic material having a high relative magnetic permeability, such as pure iron, permalloy, silicon iron, or sendust. According to the first middle yoke and the second middle yoke, the magnetic flux generated by the first magnet and the second magnet can be preferably focused on the coil. Therefore, the driving force applied to the coil can be improved.

Here, particularly in this embodiment, 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 arranged closer to the coil than the second middle yoke. That is, the middle yoke of the smaller magnet is located closer to the coil than the middle yoke of the larger magnet.

According to the configuration described above, since the first magnet is smaller than the second magnet, the magnetic field applied to the coil by the first magnet is smaller than the magnetic field applied to the coil by 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 concentrates the magnetic flux to the coil more than the second middle yoke. Highly effective. 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 distance between the first middle yoke and the second middle yoke, resulting in A balanced magnetic field can be applied to the coil. As a result, the Lorentz force generated in the coil can be brought closer to the force couple, and more suitable driving of the first base portion can be realized.

A balanced magnetic field can be realized even if the sizes of the first and second magnets are the same, but depending on the space available for arranging the magnets, it may be difficult to match the sizes of the two magnets. There is also In particular, in a mode in which the second base portion is connected to the first base portion on which the coil is provided, 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 this embodiment, as described above, even if the first magnet and the second magnet have different sizes, the distance between the first middle yoke and the second middle yoke and the coil can be adjusted. , a suitable magnetic field can be applied to the coil. Therefore, it is possible to apply an appropriate driving force to the coil and realize suitable driving.

<2>
In another aspect of the drive device of the present embodiment, the second magnet is arranged on the second base portion side when viewed from the coil.

According to this aspect, the second magnet, which is the larger magnet, is arranged on the second base side when viewed from the coil. In other words, the smaller magnet will be located on the opposite side of the coil from the second base.

Here, a space for arranging the second base portion is inevitably created on the side of the second base portion where the second magnet is provided. Therefore, it is easy to dispose a relatively large second magnet, for example, by using a space that planarly overlaps with the second base portion.

On the other hand, considering that the second base portion is also driven by the driving force transmitted from the first driving portion, it is necessary to secure a region for driving the second base portion. However, a member such as the middle yoke that is desired to be arranged at a position close to the coil (in other words, a position close to the second base) may interfere with the driving of the second base.

However, the second middle yoke provided on the second magnet has a greater 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 area of the second base portion, for example.

<3>
In the mode in which the second magnet is arranged on the second base portion side as described above, the first magnet is provided along the first side of the first base portion on the side not facing the second base portion. and a second portion provided along a second side adjacent to the first side, wherein the second magnet is located on the second base of the first base portion. a third portion provided along a third side facing the portion; 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. It may be arranged at a position closer to the coil than the part where the coil is attached.

In this case, the first portion of the first magnet is provided smaller than the third portion of the second magnet. Specifically, the first portion provided along the first side of the first base portion (that is, the side that does not face the second base portion) is provided along the third side of the first base portion (that is, , the side facing the second base portion). Therefore, the second magnet arranged on the second base portion side is larger than the first magnet. The sizes of the other second portion and the fourth portion are typically approximately the same, but are not particularly limited.

On the other hand, the portion of the first middle yoke provided on the surface of the first portion is located 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 magnitude of the first portion and the third portion is the difference in the magnetic flux convergence effect caused by the difference in the distance of the middle yoke provided in each of the first portion and the third portion. more offset. Therefore, a balanced magnetic field can be applied to the coil.

<4>
In another aspect of the drive device of the present embodiment, 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 plan view. .

According to this aspect, it is possible to prevent the first middle yoke and the second middle yoke from interfering with 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 with the first base portion and the second base portion in a plan view, but are arranged so as to overlap the first base portion and the second base portion in terms of height. 2 can be placed close to the base. Therefore, the magnetic flux convergence function of the first middle yoke and the second middle yoke can be effectively exhibited.

<5>
In another aspect of the driving device of the present embodiment, the driving device further includes a yoke inserted through the opening 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 of the first base portion. Therefore, the Lorentz force generated by applying a control current to the coil can be increased. That is, the driving force applied by the coil can be increased. Like the first middle yoke and the second middle yoke, the yoke preferably contains a soft magnetic material having a high relative magnetic permeability, such as pure iron, permalloy, silicon iron, or sendust.

In order to enhance the effect of converging the magnetic flux 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 be made large within a range that does not hinder the driving of the first base portion on which the coil is arranged. Moreover, it is preferable that the cross section of the yoke has a shape close to the shape of the opening of the first base portion.

Furthermore, the yoke is inserted from the lower side to the upper side of the first base portion, for example, and in order to enhance the effect of converging the magnetic flux by the yoke, it is preferable to configure the yoke to extend upward to some extent. For this reason, it is preferable that the yoke be long enough to drive the first base portion on which the coil is arranged.

<6>
In another aspect of the driving device of the present embodiment, it 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 part supports the driven part so that the driven part 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 elastic portion so that the second base portion supports the first driven portion in a drivable manner. good too.

According to the driving device having such a configuration, it is possible to suitably drive (for example, rotate or move) the driven part. That is, according to the driving device having such a configuration, the driven part can be driven (for example, rotated or moved) appropriately. 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 moves, the driven part supported by the second base also moves with the movement of the second base. As a result, the driven part can be driven favorably.

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

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

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

The first base 110 has a frame shape with a gap (opening) 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 in the drawing (that is, a direction orthogonal to the Y-axis direction). It has a frame shape with 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 to this, and may have other shapes (for example, a rectangular shape such as a rectangle). or circular shape). Also, the first base is not limited to a frame shape.

A coil 300 is arranged on the first base. Coil 300 is a plurality of windings made of, for example, a relatively highly conductive material (eg, gold, copper, etc.). In this embodiment, the coil 300 has a square shape along the first base 110 . However, coil 300 may have any shape (eg, rectangular, rhombic, parallelogram, circular, elliptical, or any other loop shape).

A control current is supplied to the coil 300 from a power supply via a power supply terminal (not shown) or the like. The power source may be a power source provided in the MEMS scanner 101 itself, or may be a power source provided 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 applying a control current to the coil 300 and the magnetic field of the magnet. The first base 110, on which the coil 300 is mounted, is rotated in a direction depending on the directions of the magnetic field and the control current.

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

The H torsion bar 450 is an elastic member such as a spring made of silicon, copper alloy, iron-based alloy, other metals, 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 with a long side extending in the Y-axis direction and a short side extending in the X-axis direction. One end of H torsion bar 450 is connected to second base 110 . Also, the other end of the H torsion bar 450 is connected to the mirror 400 . Therefore, the elasticity of the H torsion bar 450 allows the mirror 400 to rotate about the axis along the Y-axis direction. Mirror 400 is a specific example of a "driven part."

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

The first base 110 and the second base 120 are fixed to a substrate or support member (not shown) via V torsion bars 150 and 160 (in other words, they are fixed inside the system called the MEMS scanner 101). is being used). 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 this embodiment has a laminated structure of a support layer 10, an active layer 20, a BOX layer 30 and a metal layer 40. As shown in FIG. However, it may be a laminated structure including other layers.

Each of the support layer 10 and the active layer 20 contains, for example, silicon. The BOX layer 30 is composed of an oxide film such as SiO ₂ or the like, and is arranged 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 contains, for example, a metal with high conductivity, and is arranged 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 to extend from the first base 110 to the spring portion 210 and the second base 120 (see FIG. 2 for details). 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 respectively, but not formed on the spring portion 210 . In other words, the spring portion 210 is composed only of the support layer 20 . Also, the spring portion 210 is integrally formed 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 in the spring portion 210, but the active layer 20 is formed in the wiring spring portion 220 (see FIG. 1). Therefore, electrical connection between the first base 110 and the second base 120 can be achieved.

(2) Operation of MEMS Scanner Next, the operation of the MEMS scanner 101 according to this embodiment will be described with reference to FIG. FIG. 4 here is a side view conceptually showing the mode of operation of the MEMS scanner according to the example. 4 and subsequent drawings, for convenience of explanation, detailed members constituting the MEMS scanner 101 shown in FIGS.

As shown in FIG. 4A, in the MEMS scanner 101 according to this embodiment, an external magnetic field is applied to the coil 300 from the upper right direction to the lower right direction in the figure. An external magnetic field is applied by a magnet, which will be described later. However, the direction of the magnetic field here is an example, and the magnetic field may be applied in other directions.

In FIGS. 4A and 4B, a control current is supplied to the coil 300 during operation of the MEMS scanner 101 according to this embodiment. Then, Lorentz force is generated due to the electromagnetic interaction between the magnetic field generated by supplying the control current to the coil 300 and the external magnetic field. Specifically, opposite Lorentz forces are 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 portion 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 . In this way, the Lorentz force is generated in the coil 300, and 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 around the V torsion bars 150 and 160 as rotation axes. As a result, the mirror 400 also rotates around the X-axis, and a so-called vertical scan is performed.

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, and a so-called horizontal scan is performed.

It is preferable that the Lorentz force generated in the coil 300 be a couple during the driving described above. In particular, in driving with the Y-axis as the rotation axis, the center of rotation of the coil 300 is determined only by the dimensions, hardness, and weight of each structural part, and is easily affected when an external force is applied. If the Lorentz force generated in the coil 300 were to deviate from the force couple, other motion (for example, translational motion of the coil 300) would be mixed with the resonant motion, hindering smooth resonant motion.

In order to bring the Lorentz force generated in the coil 300 closer to the force couple, the magnetic field applied to the coil 300 is horizontal, and the strength in the left and right sides of the coil 300 (that is, the two regions where the Lorentz force is generated) is about the same. is preferably

(3) Arrangement of Magnet and Yoke Next, the arrangement of the magnet and yoke for generating a magnetic field for the MEMS scanner 101 according to this embodiment will be described with reference to FIGS. 5 to 7. FIG. FIG. 5 is a plan view showing the arrangement of magnets and middle yokes for the MEMS scanner according to the example. Also, FIG. 6 is a cross-sectional view showing the 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 magnetic fields to coils.

In FIG. 5, according to the MEMS scanner 101 according to this embodiment, the first magnet 710 is arranged on one side of the coil 300 (upper right in the drawing). The first magnet 710 has a dogleg shape 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 (bottom 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 extends). there is A second middle yoke 820 is provided on the surface of the second magnet 720 facing the coil 300 . The second magnet 720 is arranged using a relatively wide space from below the second base 120 to below the V torsion bar 160 . That is, the second magnet 720 is configured as a magnet larger than the first magnet 710 . Furthermore, the second middle yoke 820 does not cover the entire surface of the second magnet 720, but is provided at a position that does not planarly overlap the second base.

In FIG. 6, a yoke 600 extending upward from a lower yoke 650 is inserted through the coil 300 . A third magnet 730 and a fourth magnet 740 are arranged 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 is made of, for example, pure iron, permalloy, silicon iron, or sendust. It is composed of a soft magnetic material with a high relative magnetic permeability such as. According to these yokes, the magnetic fluxes generated by the first magnet 710, the second magnet 720, the third magnet 730, and the fourth magnet 740 can be suitably focused 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, 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 distance L2 between the yoke 600 and the portion along the left side of the coil 300 in the figure is configured to be smaller than the distance L2. Therefore, the magnetic flux convergence function of the first middle yoke 810 with respect to the coil 300 is higher than that of the second middle yoke 820 . Therefore, the difference in the strength of the magnetic field due to the difference in size of the first magnet 710 and the second magnet 720 is offset by the difference in the magnetic flux convergence function due to the difference in distance between the first middle yoke 810 and the second middle yoke 820. be. In other words, L1 and L2, which are the distances between the first middle yoke 810 and the second middle yoke 820, and the yoke 600, are values that can cancel out the difference in magnetic field strength of the first magnet 710 and the second magnet 720. It should 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 during driving can be brought closer to the force couple, and more suitable driving can be realized.

(4) Comparison with Comparative Example Next, comparison with a MEMS scanner 101b according to a first comparative example and a MEMS scanner 101c according to a second comparative example, which will be described with reference to FIGS. 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 for explaining whether or not there is 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 this embodiment. is established as On the other hand, the second magnet 720b and the second middle yoke 820b according to the first comparative example are provided to be 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 is Specifically, the first magnet 710b and the second magnet 720b according to the first comparative example have approximately the same size and are configured to apply the same 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 drive efficiency deteriorates. Specifically, since the empty space on the left side of the second base 120 is not effectively utilized, the magnetic field applied to the coil 300 is correspondingly weakened, 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. established 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 this embodiment. However, the second middle yoke 820 according to the second embodiment is not provided partially like the second middle yoke 820 according to the present embodiment, but rather covers the entire surface of the second magnet 720 on the coil 300 side. is provided as follows. Therefore, in the second comparative example, similarly to the above-described first comparative example, the first magnet 710c and the second magnet 720c have approximately the same size and apply the same magnetic field to the coil 300. 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 magnet 710 protrudes outside the chip. As a result, the size of the device including the magnetic circuit becomes large, resulting in an increase in the size of the device.

In FIG. 10A, in the first comparative example and the second comparative example, the second middle yoke 820 is arranged at a position overlapping the second base 120 in plan view. Therefore, for example, when the MEMS scanner 101b or 101c is driven around the V-axis (X-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 arranging the second middle yoke 820 at a position distant from the second base 120 is conceivable, but the magnetic flux convergence function of the second middle yoke 820 is reduced accordingly. .

On the other hand, in FIG. 10(b), according to the present embodiment, the second middle yoke 820 is not arranged at a position overlapping the second base 120 in plan view. Therefore, even when the MEMS scanner 101 is driven around the V-axis (X-axis), for example, interference between the second base 120 and the second middle yoke 820 can be avoided.

As described above, according to the MEMS scanner 101 according to the present embodiment, a plurality of magnets and yokes are arranged in such a manner as to 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. can. Therefore, these electronic devices are also included in the scope of the present invention.

In addition, the present invention can be modified as appropriate within the scope not contrary to the gist or idea of the invention that can be read from the scope of claims and the entire specification, and driving devices that involve such modifications are also included in the technical concept of the present invention. be

REFERENCE SIGNS LIST 10 support layer 20 active layer 30 BOX layer 40 metal layer 101 MEMS scanner 110 first base 120 second 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 First magnet 720 Second magnet 730 Third magnet 740 Fourth magnet 810 First middle yoke 820 Second middle yoke 830 Third middle yoke 840 Fourth middle yoke

Claims (1)

a first base portion coupled to the driven portion;
a coil disposed on the first base;
a first magnet arranged to surround part of the outer periphery of the coil;
a second magnet arranged to surround a portion of the outer circumference 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 is the distance from the coil to the first middle yoke in a direction different from the distance from the coil to the second middle yoke in the direction in which the driven part is arranged. A driving device characterized in that they are arranged so that the

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