JP7481984B2 - Optical Unit - Google Patents

Description

The present invention relates to an optical unit.

Conventionally, optical units have been used that include a movable body with an optical module, a fixed body, a gimbal mechanism that rotatably supports the movable body relative to the fixed body, and a drive mechanism that rotates the movable body supported by the gimbal mechanism relative to the fixed body, with the drive mechanism including a coil and a magnet. For example, Patent Document 1 discloses a lens drive device that includes a movable body with a lens, a fixed body, a first frame that rotatably supports the movable body relative to the fixed body, and a coil and a magnet that rotate the movable body supported by the first frame relative to the fixed body.

JP 2020-52415 A Japanese Patent Application Laid-Open No. 9-45261

In conventional optical units such as the lens drive device of Patent Document 1, the magnets used in the drive mechanism are very small, and the grooves into which the magnets are inserted and fixed are also very small. For this reason, depending on the dimensional accuracy of the groove into which the magnets are fixed, there are cases where the magnets cannot be inserted into the grooves or the grooves are too wide for the magnets. Patent Document 2 describes how to improve the insertion accuracy of the insert by providing a semi-cylindrical convex portion in the insertion portion. However, in order to form a semi-cylindrical convex portion, a corner portion is generated at the boundary between the convex portion and the adjacent portion of the convex portion. In this way, a configuration in which a corner portion is generated is very difficult when the object to be formed is small. This is because even if a mold is formed using sheet metal or the like, it is difficult for a resin material to enter the corners. In other words, since the magnet insertion groove in the optical unit is very small, it is difficult to form a semi-cylindrical convex portion as disclosed in Patent Document 2. Therefore, the present invention aims to easily fix a magnet used in a drive mechanism that rotates a movable body supported by a gimbal mechanism relative to a fixed body in an optical unit.

The optical unit of the present invention comprises a movable body having an optical module, a fixed body, a gimbal mechanism that rotatably supports the movable body relative to the fixed body with one or more directions intersecting with the optical axis direction as the direction of the axis of rotation, and a drive mechanism that rotates the movable body supported by the gimbal mechanism relative to the fixed body, the drive mechanism having a coil provided on one of the movable body and the fixed body, and a magnet provided on the other of the movable body and the fixed body at a position facing the coil, the magnet being bonded to the plane of a flat yoke, the yoke being inserted into a yoke insertion groove provided on the other of the movable body and the fixed body, the yoke insertion groove being provided with a convex portion that protrudes in a curved shape and contacts the plane, and a concave portion that is adjacent to the convex portion and is recessed in a direction away from the plane while maintaining a continuous curved shape relative to the convex portion.

According to this aspect, the yoke insertion groove is provided with a convex portion that protrudes in a curved shape and contacts the flat surface of the yoke, and a concave portion that is adjacent to the convex portion and is recessed in a direction away from the flat surface of the yoke while maintaining a continuous curved shape relative to the convex portion. In other words, the configuration is such that no corners are generated at the boundary between the convex portion and the adjacent portion of the convex portion. Therefore, it is easy to fix the magnet used in the drive mechanism that rotates the movable body supported by the gimbal mechanism in the optical unit relative to the fixed body.

In the optical unit of the present invention, the convex portion can be provided at a position that contacts both ends of the yoke in the longitudinal direction, and the concave portion can be arranged closer to the end than the convex portion. With this configuration, the yoke can be firmly fixed at both ends in the longitudinal direction, and the yoke insertion groove can be configured so that no corners are generated at the boundary between the convex portion and the adjacent portion of the convex portion.

In the optical unit of the present invention, the recess can be configured to be recessed not only in the direction away from the plane but also in the direction toward the end. This configuration makes it particularly easy to form the yoke insertion groove.

The optical unit of the present invention can easily secure magnets used in a drive mechanism that rotates a movable body supported by a gimbal mechanism relative to a fixed body.

FIG. 2 is a plan view of an optical unit according to an embodiment of the present invention. FIG. 1 is a perspective view of an optical unit according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of an optical unit according to an embodiment of the present invention. FIG. 4 is an exploded perspective view of an optical unit according to an embodiment of the present invention, seen from a different direction than FIG. 3. FIG. 2 is a perspective view showing a part of a movable body in an optical unit according to an embodiment of the present invention, showing a state in which a magnet is attached. FIG. 2 is a perspective view showing a part of a movable body in an optical unit according to an embodiment of the present invention, with a magnet removed; 5A and 5B are diagrams illustrating the shape of a yoke insertion groove in an optical unit according to an embodiment of the present invention. 10A and 10B are diagrams illustrating the shape of a yoke insertion groove in an optical unit according to a reference example. 9 is a diagram showing the shape of a yoke insertion groove in an optical unit according to a reference example different from that in FIG. 8 .

The following describes an embodiment of the present invention with reference to the drawings. Note that the same components in the examples and reference examples are given the same reference numerals and will be described only in the examples, and the description of the components will be omitted in the reference examples.

First, an optical unit according to an embodiment of the present invention will be described with reference to Figs. 1 to 7. In Fig. 2, the dashed line with the symbol L indicates the optical axis, the dashed line with the symbol L1 indicates a first axis line intersecting with the optical axis, and the dashed line with the symbol L2 indicates a second axis line L2 intersecting with the optical axis L and the first axis line L1. The R direction is the direction around the optical axis. In each figure, the Z-axis direction is the optical axis direction, the X-axis direction is the direction intersecting with the optical axis, in other words, the yawing axis direction, and the Y-axis direction is the direction intersecting with the optical axis, in other words, the pitching axis direction. In the X-axis, Y-axis, and Z-axis directions, the direction of the arrows is the + direction, and the opposite direction is the - direction.

<Overall configuration of optical unit>
1 to 4, an outline of the configuration of an optical unit 10 according to this embodiment will be described. The optical unit 10 includes a movable body 14 having an optical module 12, and a fixed body 16 that holds the movable body 14 in a state in which it can be displaced in a direction about the Y-axis direction as the rotation axis (pitching direction) and in a direction about the X-axis direction as the rotation axis (yawing direction).

The optical unit 10 also includes a drive mechanism 18 that drives (rotates) the movable body 14 in the pitching and yawing directions relative to the fixed body 16, and a support mechanism 20 that supports the movable body 14 rotatably in the pitching and yawing directions relative to the fixed body 16. The optical unit 10 also includes a gimbal mechanism 21 that includes a first support extension 27a that supports the movable body 14 rotatably around the first axis L1, and a second support extension 27b that supports the movable body 14 rotatably around the second axis L2 on a member on the fixed body 16 side. The support mechanism 20 can be considered to constitute a part of the gimbal mechanism 21.

<Optical module>
In this embodiment, the optical module 12 is formed in an imaging unit 14A having a substantially rectangular housing shape, and is used as a thin camera mounted on, for example, a camera-equipped mobile phone or a tablet PC. The optical module 12 has a lens 12a on the subject side (+Z direction side), and an optical device for capturing an image is built into a rectangular housing 12b. As an example, the optical module 12 in this embodiment has a built-in actuator that corrects pitching vibration (vibration in the rotation direction around the Y-axis direction as the rotation axis) and yawing vibration (vibration in the rotation direction around the X-axis direction as the rotation axis) that occurs in the optical module 12, and is configured to be able to correct pitching vibration and yawing vibration.

In this embodiment, the optical module 12 is configured to be capable of correcting pitching vibration and yawing vibration, but is not limited to this configuration. For example, the optical module 12 may be configured to be capable of correcting only one of the pitching vibration and the yawing vibration.

<About moving parts>
As shown in Fig. 3 and Fig. 4, the movable body 14 includes an imaging unit 14A having an optical module 12 and an imaging element 50, and a holder frame 14B having magnets 24A and 24B. The holder frame 14B is configured as a rectangular frame-shaped member that is provided so as to surround the remaining four faces, excluding the front face (the face on the subject side) on which the lens 12a of the optical module 12 is provided, and the rear face on the opposite side. The holder frame 14B in this embodiment is configured, as an example, so that the optical module 12 can be detachably attached. Magnets 24A and 24B for correcting pitching and yawing are attached to the outer faces of the holder frame 14B by utilizing the two faces facing the fixed body 16.

The magnet 24A is adhered to the flat surface 26a of the yoke 26A, which is a flat iron plate, and the magnet 24B is adhered to the flat surface 26a of the yoke 26B, which is a flat iron plate (see FIG. 7). The magnet 24A is fixed to the holder frame 14B by fixing the yoke 26A to the holder frame 14B, and the magnet 24B is fixed to the holder frame 14B by fixing the yoke 26B to the holder frame 14B. The detailed configuration of the fixing parts 140A and 140B of the magnets 24A and 24B to the holder frame 14B will be described later.

<About the fixed body>
3 and 4, the fixed body 16 includes a fixed frame 16A to which the coils 32A and 32B are fixed, a bottom cover portion 16B having the coils 32A and 32B and their wiring, and a top surface portion 16C through which the lens 12a passes in the +Z direction. The fixed frame 16A is provided so as to surround four surfaces of the holder frame 14B of the movable body 14 in the direction around the optical axis (R direction). The fixed body 16 in this embodiment is configured so that the flexible wiring board 51 can be covered by the fixed frame 16A and the bottom cover portion 16B, and is configured to prevent the flexible wiring board 51 from coming into contact with other components and being damaged.

Coils 32A and 32B are attached to coil attachment portions 28A and 28B, respectively. In this embodiment, coils 32A and 32B are configured as wound coils as an example, but they may also be patterned boards (coil boards) in which the coils are incorporated as a pattern into the board wiring.

In this embodiment, when the movable body 14 is disposed within the fixed body 16, the magnet 24A and the coil 32A, and the magnet 24B and the coil 32B are opposed to each other. In this embodiment, the pair of the magnet 24A and the coil 32A, and the pair of the magnet 24B and the coil 32B constitute the drive mechanism 18. The drive mechanism 18 corrects the pitching and yawing of the movable body 14. Note that in this embodiment, the drive mechanism 18 has the magnets 24A and 24B formed on the movable body 14, and the coils 32A and 32B formed on the fixed body 16, but the magnets 24A and 24B may be formed on the fixed body 16, and the coils 32A and 32B may be formed on the movable body 14.

Pitching and yawing are corrected as follows. When the optical unit 10 shakes in both the pitching direction and the yawing direction or in either one of them, the shake is detected by a magnetic sensor (Hall element) (not shown), and the drive mechanism 18 is driven based on the result. Alternatively, the shake of the optical unit 10 may be detected using a shake detection sensor (gyroscope) or the like. Based on the shake detection result, the drive mechanism 18 acts to correct the shake. That is, a current is passed through each of the coils 32A and 32B so as to move the movable body 14 in a direction that cancels the shake of the optical unit 10, thereby correcting the shake.

In this way, the optical unit 10 of this embodiment is provided with a drive mechanism 18 that rotates the movable body 14 relative to the fixed body 16 around the pitch axis direction and the yaw axis direction as the rotation axis. Here, it is preferable that the drive mechanism 18 is disposed in a position other than the side (+X direction side) where the flexible wiring board 51 is disposed in the X-axis direction relative to the movable body 14. This is because the drive mechanism 18 can be disposed on the side where the flexible wiring board 51 is not formed, so there is no need to make the optical unit 10 larger to prevent contact between the drive mechanism 18 and the flexible wiring board 51, and the optical unit 10 can be made smaller. Note that "rotation" in this specification does not necessarily mean rotating 360°, but includes the case where it oscillates in the rotational direction.

<About the support mechanism>
3 and 4, the support mechanism 20 has a metal plate 20a forming a hemispherical convex curved surface 19 facing the inside of the optical unit 10, and a metal plate 20b forming a hemispherical convex curved surface 19 facing the inside of the optical unit 10. The metal plate 20a is arranged at two opposing positions among the four corners of the rectangular holder frame 14B, and the metal plate 20b is arranged at two opposing positions among the four corners of the rectangular frame-shaped portion of the fixed frame 16A. The fixed frame 16A and the holder frame 14B are arranged so that the positions of the four corners are aligned, and the metal plate 20a and the metal plate 20b are arranged one each at the four corners.

In the support mechanism 20 of this embodiment, the concave surface 17 provided on the first support extension 27a of the gimbal mechanism 21 is arranged inside the hemispherical convex surface 19 of the inward-facing sheet metal 20a. The support mechanism 20 supports the gimbal mechanism 21 relative to the fixed body 16 in this configuration by arranging the convex surface 19 within the concave surface 17. The support mechanism 20 supports the gimbal mechanism 21 relative to the fixed body 16 in this configuration by arranging the convex surface 19 within the concave surface 17 provided on the second support extension 27b of the gimbal mechanism 21 inside the hemispherical convex surface of the inward-facing sheet metal 20b. The support mechanism 20 supports the gimbal mechanism 21 relative to the movable body 14 in this configuration by arranging the convex surface 19 within the concave surface 17. That is, the support mechanism 20 of this embodiment is configured to support the movable body 14 rotatably relative to the fixed body 16 with one or more directions (at least one direction in the X-axis direction and the Y-axis direction) intersecting with the optical axis direction (Z-axis direction) as the rotation axis direction. In addition, the support mechanism 20 in this embodiment is configured to allow the movable body 14 to rotate around the pitch axis direction as the rotation axis and the yaw axis direction as the rotation axis, but it may also be configured to allow the movable body 14 to rotate in the rolling direction as well.

<Gimbal mechanism>
The gimbal mechanism 21 is a mechanism having spring properties formed by bending a metal flat plate material. Specifically, as shown in Figs. 1 to 4, the gimbal mechanism 21 is configured by including a gimbal frame portion 25 provided on the subject side as an example, and a first support portion extension portion 27a and a second support portion extension portion 27b formed by bending the four corner portions of the gimbal frame portion 25 by 90° in the optical axis direction. Note that the first support portion extension portion 27a and the second support portion extension portion 27b do not necessarily have to be entirely plate-shaped, and only a part of them may be formed into a plate shape to exhibit spring properties. Also, one of the first support portion extension portion 27a and the second support portion extension portion 27b may be formed into a shape other than a plate shape (for example, a rod shape, etc.).

<Image sensor>
3 and 4, the optical module 12 includes an image sensor 50 on the side opposite to the subject side. A flexible wiring board 51 is connected to the image sensor 50. In this embodiment, the connection portion of the image sensor 50 with the flexible wiring board 51 is formed on the +X direction side, and the flexible wiring board 51 is covered by the fixed frame 16A and the bottom cover 16B. The connection portion of the flexible wiring board 51 does not have to be provided on the image sensor 50, and may be provided on a portion of the imaging unit 14A other than the image sensor 50.

<Flexible wiring board>
3 and 4, the flexible wiring board 51 is folded multiple times in the area between the fixed frame 16A and the bottom cover portion 16B. This configuration allows the length of the flexible wiring board 51 to be increased, and by increasing the length of the flexible wiring board 51, the load on the flexible wiring board 51 is reduced even when the movable body 14 moves relative to the fixed body 16. However, there is no particular limitation on the configuration or arrangement of the flexible wiring board 51.

<Configuration of the part fixing the magnet to the holder frame>
As described above, the magnet 24A is adhered to the yoke 26A, which is an iron plate, and the magnet 24B is adhered to the yoke 26B, which is an iron plate. As shown in Figs. 5 and 6, the magnet 24A is fixed to the holder frame 14B by fixing the yoke 26A to the fixing portion 140A of the holder frame 14B. As shown in Figs. 5 and 6, the magnet 24B is fixed to the holder frame 14B by fixing the yoke 26B to the fixing portion 140B of the holder frame 14B. The magnet 24 (magnets 24A and 24B) is fixed to the holder frame 14B by inserting the yoke 26 (yokes 26A and 26B) in the -Z direction into the yoke insertion groove 141 extending in the Z-axis direction of the fixing portion 140 (fixing portions 140A and 140B).

The detailed structure of the fixed portion 140 (fixed portions 140A and 140B) will now be described with reference to FIG. 7 and in comparison with FIG. 8 and FIG. 9. In the optical unit 10 of this embodiment, the magnets 24A and 24B, the yokes 26A and 26B, and the fixed portions 140A and 140B have the exact same structure. The holder frame 14B is made of resin, and the magnets 24A and 24B, and the yokes 26A and 26B are made of metal.

First, the fixed portion 140 in FIG. 8 of the optical unit of the reference example will be described. The fixed portion 140 in FIG. 8 has a yoke insertion groove 141 formed with a width (width in the Y-axis direction) corresponding to the thickness (thickness in the Y-axis direction) of the yoke 26. Note that FIG. 8 only shows the end of the fixed portion 140 on the -X direction side, but the end on the +X direction side has the same configuration. The yoke insertion groove 141 has a flat portion 142b that is flat in the +Y direction, and the width between the flat portion 142b and the portion facing the flat portion 142b is formed to be constant so as to be the same as the thickness of the yoke 26.

In a fixing part 140 having such a configuration, if there is variation in the thickness of the yoke 26 or the width of the yoke insertion groove 141 due to design tolerances, etc., it may be impossible to insert the yoke 26 into the yoke insertion groove 141, or the yoke 26 may easily come off the yoke insertion groove 141 and not be able to be fixed securely. In addition, the corners 143b and 144b of the yoke insertion groove 141 form an acute angle (approximately 90°). The width of the yoke insertion groove 141 of the fixing part 140 used in the optical unit is very small, on the order of microns, so it is very difficult to form a yoke insertion groove 141 that has a portion that forms an acute angle. For this reason, it is very difficult to form the fixing part 140 in FIG. 8.

Next, the fixed part 140 in FIG. 9 of an optical unit of a reference example different from that in FIG. 8 will be described. The fixed part 140 in FIG. 9 has a yoke insertion groove 141 formed with a width slightly wider than the thickness of the yoke 26. The yoke insertion groove 141 has a substantially hemispherical convex part 142c formed therein that protrudes in the +Y direction. Note that FIG. 9 only shows the end of the fixed part 140 on the -X direction side, but the end on the +X direction side has the same configuration. When inserting the yoke 26 into the fixed part 140, the convex part 142c is pressed in while being crushed by the yoke 26.

Here, the convex portion 142c has a portion that contacts the periphery 145 at an acute angle (approximately 90°). Also, like the fixed portion 140 in FIG. 8, the corners 143c and 144c of the yoke insertion groove 141 form an acute angle (approximately 90°). Since the width of the yoke insertion groove 141 of the fixed portion 140 used in the optical unit is very small, on the order of microns, it is very difficult to form the yoke insertion groove 141 that has a portion that forms an acute angle. For this reason, it is very difficult to form the fixed portion 140 in FIG. 9. The fact that it is very difficult to form the fixed portion 140 in FIG. 9 means that it is difficult to form a configuration that easily fixes the magnet 24, which corresponds to the difficulty of easily fixing the magnet 24.

Next, the fixed portion 140 in FIG. 7 of the optical unit 10 of this embodiment will be described. Like the fixed portion 140 in FIG. 9, the fixed portion 140 in FIG. 7 has a yoke insertion groove 141 formed with a width slightly wider than the thickness of the yoke 26. The yoke insertion groove 141 has a convex portion 142a formed therein that protrudes in a curved shape in the +Y direction. Note that FIG. 7 only shows the end of the fixed portion 140 on the -X direction side, but the end on the +X direction side has the same configuration. When inserting the yoke 26 into the fixed portion 140, the convex portion 142a is pressed in while being crushed by the yoke 26.

In this way, the yoke insertion groove 141 is provided with a convex portion 142a that protrudes in a curved shape and contacts the flat surface 26a of the yoke 26. Furthermore, as shown in FIG. 7, the yoke insertion groove 141 is provided with a concave portion 143a that is adjacent to the convex portion 142a and is concave in a direction away from the flat surface 26a (-Y direction) while maintaining a continuously curved shape relative to the convex portion 142a.

In this way, in the optical unit 10 of this embodiment, the yoke insertion groove 141 is provided with a convex portion 142a that protrudes in a curved shape and contacts the flat surface 26a of the yoke 26, and a concave portion 143a that is adjacent to the convex portion 142a and is recessed in a direction away from the flat surface 26a of the yoke 26 while maintaining a continuously curved shape relative to the convex portion 142a. In other words, the fixed portion 140 in the optical unit 10 of this embodiment is configured so that no corners are generated at the boundary between the convex portion 142a and the adjacent portion of the convex portion 142a. Therefore, since the optical unit 10 of this embodiment can easily form the yoke insertion groove 141, it is possible to easily fix the magnet 24 used in the drive mechanism 18 that rotates the movable body 14 supported by the gimbal mechanism 21 relative to the fixed body 16.

In the optical unit 10 of this embodiment, the portion 144a that faces the recess 143a in the yoke insertion groove 141 in the Y-axis direction is also curved. Therefore, the optical unit 10 of this embodiment can particularly easily form the yoke insertion groove 141, and therefore can particularly easily fix the magnet 24 used in the drive mechanism 18 that rotates the movable body 14 supported by the gimbal mechanism 21 relative to the fixed body 16.

As described above, in FIG. 7, only the end of the fixed portion 140 on the -X direction side is shown, but the end on the +X direction side has the same configuration. Therefore, in the optical unit 10 of this embodiment, the convex portion 142a is provided at a position that contacts both ends of the yoke 26 in the longitudinal direction (X axis direction), and the concave portion 143a is disposed on the end side of the convex portion 142a. With this configuration, the yoke 26 can be firmly fixed at both ends in the longitudinal direction, and the yoke insertion groove 141 can be configured so that there are no corners at the boundary between the convex portion 142a and the adjacent portion of the convex portion 142a. Note that in this specification, "end" does not mean only the tip, but also includes the portion near the tip.

The recess 143a may be configured to be recessed not only in the direction away from the plane 26a (-Y direction) but also in the direction toward the end (direction along the X-axis: -X direction in FIG. 7). This configuration makes it particularly easy to form the yoke insertion groove 41.

The present invention is not limited to the above-mentioned embodiments, and can be realized in various configurations without departing from the spirit of the present invention. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention column can be replaced or combined as appropriate to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate.

10...optical unit, 12...optical module, 12a...lens, 12b...housing, 14...movable body, 14A...imaging unit, 14B...holder frame, 16...fixed body, 16A...fixed frame, 16B...bottom cover portion, 16C...upper surface portion, 17...concave surface, 18...driving mechanism, 19...convex surface, 20...support mechanism, 20a...sheet metal, 20b...sheet metal, 21...gimbal mechanism, 24...magnet, 24A...magnet, 24B...magnet, 25...gimbal frame portion, 26...yoke, 26A...yoke, 26B...yoke, 27a ...First support extension, 27b...Second support extension, 28A...Coil mounting portion, 28B...Coil mounting portion, 32A...Coil, 32B...Coil, 50...Image sensor, 51...Flexible wiring board, 140...Fixed portion, 140A...Fixed portion, 140B...Fixed portion, 141...Yoke insertion groove, 142a...Convex portion, 142b...Flat portion, 142c...Convex portion, 143a...Concave portion, 143b...Corner portion, 143c...Corner portion, 144a...Part, 144b...Corner portion, 144c...Corner portion, 145...Surroundings, L...Optical axis

Claims (3)

a movable body including an optical module;
A fixed body;
a gimbal mechanism that supports the movable body rotatably relative to the fixed body with one or more directions intersecting an optical axis direction as a rotation axis direction;
a drive mechanism that rotates the movable body supported by the gimbal mechanism relative to the fixed body,
the drive mechanism includes a coil provided on one of the movable body and the fixed body, and a magnet provided on the other of the movable body and the fixed body at a position facing the coil,
The magnet is attached to a flat surface of a flat yoke,
the yoke is inserted into a yoke insertion groove provided in the other of the movable body and the fixed body,
an optical unit characterized in that the yoke insertion groove is provided with a convex portion that protrudes in a curved shape and contacts the plane, and a concave portion that is adjacent to the convex portion and is recessed in a direction away from the plane while maintaining a continuously curved shape relative to the convex portion. 2. The optical unit according to claim 1,
the protrusions are provided at positions contacting both ends of the yoke in the longitudinal direction,
The optical unit according to claim 1, wherein the recess is disposed closer to the end portion than the protrusion. 3. The optical unit according to claim 2,
The optical unit according to claim 1, wherein the recess is recessed not only in a direction away from the flat surface but also in a direction toward the end portion.

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