Diaphragm mechanism

Abstract

An object is to provide a diaphragm mechanism that can be miniaturized. A diaphragm mechanism A includes a frame portion 1 formed around an optical axis, a diaphragm plate 2 provided so as to be movable in a direction intersecting the optical axis with respect to the frame portion 1 and configured to change an opening area that opens in the optical axis direction as it moves, and a drive unit 3 that drives the diaphragm plate 2 to move. The drive unit 3 includes an SIDM31 as a drive source that generates a driving force in a linear direction by expanding and contracting in the linear direction in response to energization, a conversion unit 32 that converts the driving force in the linear direction of the SIDM31 into a rotational driving force, and a rotational transmission unit 33 that is continuous with the conversion unit 32 and connected to the diaphragm plate 2 and rotates about a rotation center.

Description

Technical Field

[0001] The present invention relates to a diaphragm mechanism applicable to a camera incorporated in an information device such as a smartphone or a tablet.

Background Art

[0002] As a conventional technique, for example, there is a diaphragm mechanism described in Japanese Patent Application Laid-Open No. 2011-90028. In this conventional technique, a galvanometer is used as a drive source for moving the diaphragm plate. Since a galvanometer is composed of a combination of a coil, a permanent magnet, and a spring, it is difficult to miniaturize the diaphragm mechanism, and there is room for improvement in applying it to a camera incorporated in an information device.

Summary of the Invention

Problems to be Solved by the Invention

[0003] In view of this, an object of the present invention is to provide a diaphragm mechanism that can be miniaturized.

Means for Solving the Problems

[0004] One aspect of the present invention is a diaphragm mechanism that increases or decreases the light passing area in the optical axis direction, including a frame portion formed around the optical axis, a diaphragm plate provided movably in a direction intersecting the optical axis with respect to the frame portion and configured to change the opening area that opens in the optical axis direction as it moves, and a drive unit that drives to move the diaphragm plate. The drive unit includes a SIDM (Smooth Impact Drive Mechanism) as a drive source that generates a linear driving force by expanding and contracting in a linear direction in response to energization, a conversion unit that converts the linear driving force of the SIDM into a rotational driving force, and a rotational transmission unit that is continuous with the conversion unit and connected to the diaphragm plate and rotates around a rotation center.

[0005] In addition, a pair of combinations of the aperture plate and the drive unit can also be provided in two pairs sandwiching the optical axis in a direction intersecting the optical axis.

[0006] The SIDM has an output shaft extending along the linear direction, the conversion unit has a pair of clamping portions facing each other in the optical axis direction, the output shaft is sandwiched between the pair of clamping portions so as to allow slippage, and in the conversion unit, the driving force in the linear direction on the output shaft is converted into the rotational driving force by contact between the outer peripheral surface of the output shaft and the pair of clamping portions, so that the rotational transmission unit can be configured to rotate and move.

[0007] Each opposing surface of the pair of clamping portions can also be configured to be a flat surface.

[0008] In the pair of clamping portions, a distance holding portion that holds the distance between the pair of clamping portions can also be provided at a position radially symmetric with respect to the rotation center of the conversion unit with respect to the position where the outer peripheral surface of the output shaft contacts.

[0009] The distance holding portion can also be configured as a rotating body sandwiched between the pair of clamping portions and rotatable with respect to the pair of clamping portions.

[0010] The rotating body can also be configured as a sphere.

[0011] At least one of the pair of clamping portions can also have a concave portion into which a part of the sphere fits.

[0012] The concave portion can also be configured as a through hole penetrating at least one of the pair of clamping portions.

[0013] The conversion unit has a biasing portion, and the biasing portion can also be configured to apply a biasing force in the opposing direction of the pair of clamping portions so as to keep the distance constant with respect to the pair of clamping portions.

[0014] The rotation transmission unit has a permanent magnet curved along the circumferential direction with respect to the rotation center, and the frame unit may have a magnetic force detection element at a position facing the permanent magnet in the optical axis direction.

[0015] The aperture plate can also be supported at an end far from the rotation center.

[0016] The aperture plate has a long hole extending along a direction orthogonal to the moving direction with respect to the frame unit and the optical axis direction, and the end of the rotation transmission unit can be connected to the long hole.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0018] An aperture mechanism A according to an embodiment of the present invention will be described while showing the drawings. Note that in the following, the "optical axis" will be described as passing through the centers of the respective lenses in a lens assembly B in which a plurality of lenses are combined.

[0019] The aperture mechanism A of this embodiment is applied to a camera incorporated in, for example, an information device (such as a smartphone) not shown in the figure, and is configured to increase or decrease the light passing area in the optical axis direction in order to allow an appropriate amount of light to reach the imaging element C. FIG. 1 shows an example of the configuration of the aperture mechanism A and related mechanisms. The vertical direction in FIG. 1 coincides with the optical axis direction (the direction of the optical axis in the aperture mechanism A, the lens assembly B, and the imaging element C). This optical axis direction is along the surface (in many cases, the surface having the screen) and the back surface of the information device, and is along the long side or the short side. In FIG. 1, a prism D, an aperture mechanism A, a lens assembly B, and an imaging element C are combined in order from the incident side of the imaging light. Note that a part of the lens assembly B is arranged overlapping inside the aperture mechanism A. The prism D refracts the imaging light taken in from the outside through an opening, for example, on the back surface of the information device, and guides it to the aperture mechanism A. The imaging light that has passed through the aperture mechanism A reaches the imaging element C through the lens assembly B. Although not shown, an autofocus mechanism for forming an image on the imaging element C is also provided.

[0020] The aperture mechanism A mainly includes a frame portion 1, an aperture plate 2, and a drive portion 3. FIGS. 2 to 5 show the shapes and positional relationships of the respective portions. The frame portion 1 is a portion formed around the optical axis. The frame portion 1 of the present embodiment is rectangular when viewed in the optical axis direction and is a box-shaped body (specifically, a rectangular parallelepiped) that is flattened in the optical axis direction. The bottom portion 11 (the portion closer to the lens assembly B) of the frame portion 1 has openings in the region around the optical axis and the portion where the conversion portion 32 is supported, and the other regions are closed. A drive substrate 14 is provided in the closed region of the bottom portion 11, is electrically connected to the main body side of the information device, controls the energization to the drive portion 3, and receives a detection signal related to the operation of the drive portion 3. A flexible substrate is used for the drive substrate 14. On the other hand, the top portion 12 (the portion closer to the prism D) has an opening on the entire surface, and a cover plate 16 having a substantially rectangular opening in the center is attached outside the frame portion 1 with respect to the aperture plate 2. The cover plate 16 prevents the imaging light from passing through the frame portion 1 except for the portion corresponding to the opening formed by the light transmissive portion 21 (described later) of the aperture plate 2. Also, the four side portions 13 are closed. Note that the frame portion 1 only needs to be configured to be able to support at least the aperture plate 2 and the drive portion 3, and the form can be variously changed according to the shape of the object (such as an information device) to which the aperture mechanism A is to be installed. For this reason, it does not necessarily have to be in a frame shape.

[0021] The aperture plate 2 is provided so as to be movable in a direction intersecting the optical axis with respect to the frame portion 1. The aperture plate 2 of the present embodiment reciprocates in a direction orthogonal to the optical axis and along a straight line along the long side of the frame portion 1. The aperture plate 2 is guided and moved, for example, on the inner surface of the side portion 13 of the frame portion 1. In the aperture mechanism A, a pair (two sheets) of aperture plates 2, 2 are arranged in the frame portion 1 so as to partially overlap in the optical axis direction. When viewed from the optical axis direction, the pair of aperture plates 2, 2 coincide with the optical axis and are symmetrically arranged with respect to a straight line parallel to the short side of the frame portion 1. And the pair of aperture plates 2, 2 are controlled so that each moves synchronously. That is, one and the other of the pair of aperture plates 2, 2 move in a straight line direction by the same distance per unit time when reciprocating. Each aperture plate 2 has a shape in which a notch is formed inside from one short side of a rectangular flat plate, and this portion is a light transmitting portion 21 that allows imaging light to pass through in the optical axis direction. The notch of the light transmitting portion 21 has a straight line portion along the long side of the rectangle, and a hypotenuse portion that is continuous inward of the rectangle with respect to this straight line portion and is linear and inclined with respect to the long side and the short side. Thereby, the light transmitting portion 21 becomes a horizontally long hexagonal shape (when the opening is wide) or a rhombus shape (when the opening is narrow) according to the movement of the aperture plate 2 in combination with the pair of aperture plates 2, 2. FIG. 7 shows examples of a plurality of movement states (opening degrees) of one of the pair of aperture plates 2, 2 by solid lines and two-dot chain lines. The aperture plate 2 can be moved steplessly, or can be moved stepwise so as to have an opening degree corresponding to the aperture value (for example, each opening degree shown in FIG. 7).

[0022] The aperture plate 2 is supported at an end on the side far from the rotation center of the rotation transmission part 33 (described later) in the drive part 3 (the corner of the rectangle / the lower corner in FIG. 5). By setting such a positional relationship, the rotation transmission part 33 can be arranged so as to overlap the aperture plate 2 when viewed in the optical axis direction. Therefore, no useless space is generated inside the frame part 1, and the aperture mechanism A can be configured compactly. The aperture plate 2 has a long hole 22 extending along the moving direction with respect to the frame part 1 and the direction orthogonal to the optical axis direction. The end part of the rotation transmission part 33 enters this long hole 22, and a connection protrusion 332 protruding parallel to the rotation axis of the rotation transmission part 33 at the end part enters, so that power can be transmitted from the rotation transmission part 33 to the aperture plate 2 in a connectable manner. In the present embodiment, as shown in FIG. 5, the long hole 22 is formed along the short side at the corner on the lower end side of the aperture plate 2. The connection protrusion 332 is formed in a columnar shape with a circular cross-section. Since the connection protrusion 332 can move inside the long hole 22, the long hole 22 can absorb the displacement between the rotation transmission part 33 that rotates and the aperture plate 2 that moves linearly. Therefore, the rotational movement of the rotation transmission part 33 can be smoothly converted into the linear movement of the aperture plate 2. The aperture plate 2 configured as described above can change the opening area that opens in the optical axis direction by the light transmitting part 21 in the combination of the pair of aperture plates 2, 2 as it moves with respect to the frame part 1. In the present embodiment, since the pair of aperture plates 2 are configured to move with the optical axis interposed therebetween, the change in the opening area that opens in the axial direction can be made rapid.

[0023] The drive part 3 is a part that drives to move the aperture plate 2. As shown in FIG. 5, two pairs of combinations of the aperture plate 2 and the drive part 3 are provided with the optical axis interposed therebetween in the direction intersecting the optical axis (specifically, the orthogonal direction). As shown in FIG. 6, the drive part 3 includes a SIDM (Smooth Impact Drive Mechanism) 31 as a drive source, a conversion part 32, and a rotation transmission part 33.

[0024] The SIDM31 generates a driving force in the linear direction by expanding and contracting in the linear direction in response to energization. Since the SIDM itself is a known device, the explanation will be brief. The SIDM31 has an output shaft 311 that extends along the linear direction, which is the direction of the driving force. The output shaft 311 is a straight rod, for example, made of CFRP. At one end in the axial direction of the output shaft 311 (the end close to the end of the frame portion 1), a piezoelectric element 312 and a weight 313 are provided integrally with the output shaft 311. The weight 313 of the SIDM31 is fixed to the inner surface of the frame portion 1 by adhesion or the like as shown in FIG. 2. Electric power is supplied to the piezoelectric element 312 from the drive substrate 14. The piezoelectric element 312 expands and contracts in the axial direction when energized. That is, the mode of this piezoelectric element 312 is the d33 mode. By adjusting the energization state, the elongation of the piezoelectric element 312 is performed gently while the shortening is performed rapidly, or the elongation is performed rapidly while the shortening is performed gently, that is, by providing a difference between the elongation and the shortening, a driving force in one direction in the linear direction can be transmitted to the object to which the driving force is transmitted (the conversion unit 32 in this embodiment) by frictional force on the outer peripheral portion of the output shaft 311. By changing the modes of elongation and shortening of the piezoelectric element 312, the transmission direction of the driving force can be determined. Note that the energization of the SIDM31 is not continuous and is performed intermittently during elongation or shortening. Therefore, the power consumption for driving can be suppressed. Also, it can be energized both during elongation and shortening, or it can be energized only when causing rapid deformation.

[0025] The conversion unit 32 is a part that converts the driving force in the linear direction generated from the SIDM 31 into a rotational driving force. The conversion unit 32 has a columnar support portion 323 rotatably supported by the bottom portion 11 of the frame portion 1. A sphere is provided at the portion of the frame portion 1 that supports the support portion 323, and the conversion unit 32 is configured to rotate smoothly. The conversion unit 32 has a pair of clamping portions 321, 321 that face each other in the optical axis direction. The pair of clamping portions 321, 321 are integrated by concave-convex fitting as shown in, for example, FIG. 3 or FIG. 6, and are thus integrally rotatable. The clamping portion 321 is in the shape of a disk. For this reason, the opposing surfaces 3211 of the pair of clamping portions 321, 321 are flat surfaces. The output shaft 311 of the SIDM 31 is in contact with the pair of clamping portions 321, 321 (the opposing surfaces 3211 facing inward) so that friction is generated, and is clamped so as to allow slippage. The friction acts in the axial direction of the output shaft 311. The slippage occurs in the circumferential direction of the clamping portion 321. The arrangement of the SIDM 31 with respect to the conversion unit 32 is such that the circumferential direction (or tangential direction) of the clamping portion 321 is along the axial direction of the output shaft 311. For this reason, the driving force in the linear direction by the SIDM 31 is transmitted as a force directed in the circumferential direction to the clamping portion 321 by the friction acting between the output shaft 311 and the clamping portion 321. Since this transmitted force is the rotational driving force, the direction of the force is converted from the linear direction to the rotational direction between the output shaft 311 of the SIDM 31 and the clamping portion 321 of the conversion unit 32. In the present embodiment, since the clamping portion 321 is flat and contacts the output shaft 311, the contact area between the output shaft 311 and the pair of clamping portions 321, 321 can be made constant regardless of the rotation angle of the conversion unit 32, so that the conversion of the driving force can be performed stably. As described above, in the conversion unit 32, the driving force in the linear direction on the output shaft 311 is converted into a rotational driving force by the contact between the outer peripheral surface of the output shaft 311 and the pair of clamping portions 321, 321, whereby the rotation transmission unit 33 rotates and moves. According to this configuration, there is an advantage that the configuration for converting the driving force in the linear direction generated from the SIDM 31 into a rotational driving force can be simplified. Further, when the conversion unit 32 is stopped, the position holding is performed by the friction between the output shaft 311 of the SIDM 31 and the clamping portion 321, so that no power is required for position holding.

[0026] In a pair of clamping portions 321, 321, at a position where the outer peripheral surface of the output shaft 311 in the SIDM 31 comes into contact, an interval holding portion 3212 for maintaining the interval between the pair of clamping portions 321, 321 is provided at a position that is radially symmetric (a position 180 degrees apart in the circumferential direction) with respect to the rotation center of the conversion portion 32. Due to the interval holding portion 3212 combined with the output shaft 311, the distance in the facing direction of the pair of clamping portions 321, 321 is kept constant, so that the driving force of the output shaft 311 can be stably transmitted to the conversion portion 32. The interval holding portion 3212 is sandwiched between the pair of clamping portions 321, 321 and is a rotating body that can rotate with respect to the pair of clamping portions 321, 321. Since the interval holding portion 3212 is a rotating body, even if a positional deviation in the rotation direction occurs between the pair of clamping portions 321, 321, the interval holding portion 3212 is not affected. Specifically, the interval holding portion 3212 is a sphere with a circular cross-section, and for example, a metal sphere or a ceramic sphere is used. By making it a sphere, a rotatable rotating body can be easily formed and general-purpose products can be used. The rotation of the interval holding portion 3212 is possible in all directions. Corresponding to this interval holding portion 3212, at least one of the pair of clamping portions 321, 321 has a recess 3213 into which a part of the sphere fits. Due to this recess 3213, the spherical interval holding portion 3212 can be held at a fixed position in the clamping portion 321. In the present embodiment, the recess 3213 is a through-hole that penetrates in the thickness direction of the clamping portion 321, and the spherical interval holding portion 3212 is fitted therein in a rotatable state. By making it a through-hole, the formation of the recess 3213 can be facilitated compared to having a bottom. In combination with the recess 3213, the interval holding portion 3212 is rotatably supported at a fixed position in the clamping portion 321. In this way, in the pair of clamping portions 321, 321, the contact location of the output shaft 311 of the SIDM 31 and the interval holding portion 3212 are provided at positions that are radially symmetric. Therefore, the distance in the facing direction of the pair of clamping portions 321, 321 is kept constant. Accordingly, the frictional force related to the contact can be kept constant between the output shaft 311 of the SIDM 31 and the clamping portion 321, so that the driving force of the output shaft 311 can be stably transmitted to the conversion portion 32.

[0027] The conversion unit 32 has a biasing unit 322. The biasing unit 322 applies a biasing force to the pair of clamping units 321, 321 in the facing direction of the pair of clamping units 321, 321 so as to keep the interval constant. With this biasing unit 322, the degree of contact between the output shaft 311 of the SIDM 31 and the pair of clamping units 321, 321 can be kept constant, and the spherical spacing holding unit 3212 can be prevented from coming off the concave portion 3213. As the biasing unit 322 of the present embodiment, a coil spring which is a compression spring is used. The biasing unit 322 is wound around the shaft portion of a connecting member 324 which is a screw. The connecting member 324 is screwed to the clamping unit 321 on the side opposite to the biasing unit 322, and is movable in the axial direction with respect to the clamping unit 321 on the side in contact with the biasing unit 322. The clamping unit 321 on the side in contact with this biasing unit 322 (coil spring) is biased so that the clamping unit 321 on the opposite side (the facing side) is attracted by the reaction force of the spring force. By this biasing, the interval between the pair of clamping units 321, 321 is kept so as to be narrowed.

[0028] The rotation transmission unit 33 is continuous with the conversion unit 32 and is connected to the aperture plate 2, and rotates and moves with reference to the rotation center. Note that the rotation center is not in the rotation transmission unit 33 itself, but is located in the clamping unit 321 in the conversion unit 32. The direction in which the rotation center extends is parallel to the optical axis direction. In the present embodiment, it is an arm-like portion 331 extending radially from the disk-shaped clamping unit 321 located on the top portion 12 side of the frame portion 1 among the pair of conversion units 32. This arm-like portion 331 is provided integrally with the clamping unit 321 and is formed as a single flat plate. The rotation transmission unit 33 has a connecting protrusion 332 for connecting to the aperture plate 2. In the rotation transmission unit 33 having the arm-like portion 331, according to the ratio between the radial distance from the rotation center in the conversion unit 32 to the contact position of the output shaft 311 in the SIDM 31 and the distance from the rotation center to the connecting protrusion 332, the movement distance of the connecting protrusion 332 in the output of the driving force of the rotation transmission unit 33 can be adjusted with respect to the input of the driving force from the SIDM 31. Therefore, the movement distance of the aperture plate 2 in the frame portion 1 can be adjusted, and a desired output (that is, movement distance) can be set.

[0029] The rotation transmission unit 33 has a permanent magnet 333 that is curved along the circumferential direction with respect to the rotation center of the conversion unit 32. The permanent magnet 333 is arranged such that one pole (for example, the N pole) is located on one side in the circumferential direction of the rotation transmission unit 33, and the other pole (for example, the S pole) is located on the other side. Correspondingly, the frame portion 1 has a magnetic force detection element 15 at a position facing the permanent magnet 333 in the optical axis direction. As the magnetic force detection element 15, for example, a Hall element or an MR element is used. The detection signal of the magnetic force detection element 15 is sent to the drive substrate 14. The detection result of the magnetic force detection element 15 is used in a control unit (not shown) provided in the object to which the aperture mechanism A is applied (information device). Based on the detection result, the control unit controls the drive unit 3 (specifically, the energization of the SIDM 31). By such a combination of the permanent magnet 333 and the magnetic force detection element 15, the rotation state of the rotation transmission unit 33 can be grasped.

[0030] As described above, the present embodiment is an aperture mechanism A that increases or decreases the light passing area in the optical axis direction, and includes a frame portion 1 formed around the optical axis, a diaphragm plate 2 that is provided so as to be movable in a direction intersecting the optical axis with respect to the frame portion 1 and whose opening area that opens in the optical axis direction changes as it moves, and a drive unit 3 that drives to move the diaphragm plate 2. The drive unit 3 includes an SIDM 31 as a drive source that generates a driving force in a linear direction by expanding and contracting in the linear direction in response to energization, a conversion unit 32 that converts the driving force in the linear direction of the SIDM 31 into a rotational driving force, and a rotation transmission unit 33 that is continuous with the conversion unit 32 and is connected to the diaphragm plate 2 and rotates around a rotation center. By this configuration, by using the SIDM 31 and configuring the diaphragm plate 2 to be moved by the conversion unit 32 and the rotation transmission unit 33, a compact aperture mechanism A can be realized.

[0031] Also, a pair of combinations of the diaphragm plate 2 and the drive unit 3 can be provided in two pairs sandwiching the optical axis in a direction intersecting the optical axis. With this configuration, since each diaphragm plate 2 belonging to the two pairs is configured to move with the optical axis interposed therebetween, the change in the opening area that opens in the axial direction can be made rapid.

[0032] Further, the SIDM31 has an output shaft 311 extending along the linear direction, the conversion unit 32 has a pair of clamping portions 321, 321 facing each other in the optical axis direction, the output shaft 311 is clamped by the pair of clamping portions 321, 321 so as to allow slippage, and in the conversion unit 32, the driving force in the linear direction on the output shaft 311 is converted into the rotational driving force by the contact between the outer peripheral surface of the output shaft 311 and the pair of clamping portions 321, 321, so that the rotational transmission unit 33 can be configured to rotate and move. With this configuration, the configuration for converting the linear driving force generated from the SIDM31 into the rotational driving force can be simplified.

[0033] Further, each opposing surface 3211 of the pair of clamping portions 321, 321 can also be configured to be a flat surface. With this configuration, by contacting with a flat surface, the contact area between the output shaft 311 of the SIDM31 and the pair of clamping portions 321, 321 can be made constant regardless of the rotational angle of the conversion unit 32, so that the conversion of the driving force can be stably performed.

[0034] Further, in the pair of clamping portions 321, 321, a distance holding portion 3212 for holding the distance between the pair of clamping portions 321, 321 can also be provided at a position radially symmetric with respect to the rotation center of the conversion unit 32 with respect to the position where the outer peripheral surface of the output shaft 311 contacts. With this configuration, since the distance holding portion 3212 keeps the distance in the opposing direction of the pair of clamping portions 321, 321 constant, the driving force of the output shaft 311 can be stably transmitted to the conversion unit 32.

[0035] Further, the distance holding portion 3212 can also be configured as a rotating body sandwiched between the pair of clamping portions 321, 321 and rotatable with respect to the pair of clamping portions 321, 321. With this configuration, since the distance holding portion 3212 is a rotating body, the distance holding portion 3212 is not affected even if a positional deviation in the rotational direction occurs between the pair of clamping portions 321, 321.

[0036] Further, the rotating body can also be formed as a sphere. With this configuration, a rotatable rotating body can be easily formed.

[0037] Also, at least one of the pair of clamping portions 321, 321 can have a recess 3213 into which a part of the sphere fits. With this configuration, the recess 3213 can hold the spherical spacing holding portion 3212 at a fixed position in the clamping portion 321.

[0038] Also, the recess 3213 can be configured as a through hole that penetrates at least one of the pair of clamping portions 321, 321. With this configuration, the formation of the recess 3213 can be facilitated.

[0039] Also, the conversion portion 32 has a biasing portion 322, and the biasing portion 322 can be configured to apply a biasing force in the facing direction of the pair of clamping portions 321, 321 so as to keep the distance between the pair of clamping portions 321, 321 constant. With this configuration, the degree of contact between the output shaft 311 of the SIDM 31 and the pair of clamping portions 321, 321 can be kept constant, and the spherical spacing holding portion 3212 can be prevented from coming out of the recess 3213.

[0040] Also, the rotation transmission portion 33 has a permanent magnet 333 that is curved along the circumferential direction with respect to the rotation center, and the frame portion 1 can have a magnetic force detection element 15 at a position facing the permanent magnet 333 in the optical axis direction. With this configuration, the rotation state of the rotation transmission portion 33 can be grasped by the combination of the permanent magnet 333 and the magnetic force detection element 15.

[0041] Also, the aperture plate 2 can be supported at the end on the side far from the rotation center. With this configuration, the rotation transmission portion 33 can be arranged so as to overlap the aperture plate 2 when viewed in the optical axis direction, so that the aperture mechanism A can be configured compactly.

[0042] Further, the aperture plate 2 has a long hole 22 extending along the moving direction with respect to the frame portion 1 and in a direction orthogonal to the optical axis direction, and the end portion of the rotation transmission portion 33 can also be connected to the long hole 22. With this configuration, the long hole 22 can absorb the displacement between the rotation transmission portion 33 and the aperture plate 2, so that the rotational movement of the rotation transmission portion 33 can be smoothly converted into the linear movement of the aperture plate 2.

[0043] According to the aperture mechanism A of the present embodiment, by using the SIDM 31 and configuring the aperture plate 2 to be moved by the conversion portion 32 and the rotation transmission portion 33, a compact configuration can be realized. Therefore, the aperture mechanism A can be miniaturized. Since miniaturization is possible, for example, it can also be applied to a built-in camera of a foldable smartphone that is thinner than a conventional smartphone.

[0044] The present embodiment is as described above. However, the present invention is not limited to the above-described form, and can be appropriately designed and changed within the scope intended by the present invention. Also, the effects of the present invention are not limited to those described in the above embodiment. That is, the disclosed embodiment is illustrative in all respects and does not limit the present invention. The scope of the present invention is defined by the claims rather than the foregoing description. Also, it is intended that the scope of the present invention includes all modifications within the meaning and scope equivalent to the claims.

[0045] For example, the aperture mechanism A of the present embodiment has been described as being used for a camera built in an information device (such as a smartphone). However, it is not limited to this, and it can also be used for a single-function camera, or can be incorporated and used in other devices (such as in-vehicle devices such as car navigation devices, household appliances such as air conditioners, and intercoms). Furthermore, the aperture mechanism A can also be incorporated and used in an optical device other than a camera.

[0046] Regarding the aperture plate 2, in the above-described embodiment, a pair of two plates was used, but it may be configured with only one plate, or three or more plates. Further, even when configured with two plates, one aperture plate 2 may be fixed to the frame portion 1 without moving it.

[0047] Regarding the drive unit 3, only one set of the drive unit 3 (particularly the SIDM 31 and the conversion unit 32 among them) may be configured, and the driving force may be branched by the rotation transmission unit 33, and the pair (two sheets) of aperture plates 2, 2 may be moved by the branched driving force.

[0048] Regarding the conversion unit 32, the clamping portion 321 was disc-shaped in the above-described embodiment, but it is not limited thereto, and for example, it may be a sector corresponding to the range of rotational movement. Further, the contact with friction between the output shaft 311 of the SIDM 31 and the clamping portion 321 may be made directly, or a sheet-like body separate from the output shaft 311 and the clamping portion 321 may be interposed. Further, the friction can also be adjusted by performing processing such as coating or unevenness on the outer peripheral surface of the output shaft 311 or the opposing surface 3211 of the clamping portion 321.

[0049] Regarding the rotation transmission unit 33, in the above-described embodiment, it was configured by the arm-shaped portion 331, but it can be configured in various ways capable of transmitting the driving force from the drive unit 3 and the conversion unit 32 to the aperture plate 2.

Explanation of Reference Numerals

[0050] 1 Frame portion 11 Bottom portion of the frame portion 12 Top portion of the frame portion 13 Side portion of the frame portion 14 Drive substrate 15 Magnetic force detection element 16 Cover plate 2 Aperture plate 21 Light-transmitting portion 22 Long hole 3 Drive unit 31 SIDM 311 Output shaft 312 Piezoelectric element 313 Weight 32 Conversion Unit 321 Clamping Unit 3211 Opposing Surface 3212 Spacing Retaining Unit 3213 Recess 322 Biasing Unit 323 Support Unit 324 Connecting Member 33 Rotation Transmission Unit 331 Arm-shaped Portion 332 Connecting Projection 333 Permanent Magnet A Diaphragm Mechanism B Lens Assembly C Image Sensor D Prism

Claims

1. A diaphragm mechanism for increasing or decreasing the light passing area in the optical axis direction, comprising: a frame portion formed around the optical axis; a diaphragm plate provided movably in a direction intersecting the optical axis with respect to the frame portion, and the opening area opening in the optical axis direction is changed as it moves; a drive unit for driving to move the diaphragm plate, and having: the drive unit includes: a SIDM (Smooth Impact Drive Mechanism) as a drive source that generates a driving force in a linear direction by expanding and contracting in a linear direction in response to energization; a conversion unit that converts the linear driving force of the SIDM into a rotational driving force; a rotation transmission unit that is continuous with the conversion unit and connected to the diaphragm plate, and rotates and moves with respect to a rotation center; a diaphragm mechanism.

2. The diaphragm mechanism according to claim 1, wherein a pair of combinations of the diaphragm plate and the drive unit are provided in two pairs sandwiching the optical axis in a direction intersecting the optical axis.

3. The SIDM has an output shaft extending along the linear direction, the conversion unit has a pair of clamping portions facing each other in the optical axis direction, the output shaft is sandwiched between the pair of clamping portions so as to allow slippage, In the conversion unit, the linear driving force on the output shaft is converted into the rotational driving force by contact between the outer peripheral surface of the output shaft and the pair of clamping portions, so that the rotation transmission unit rotates and moves. The diaphragm mechanism according to claim 1 or 2.

4. The diaphragm mechanism according to claim 3, wherein each opposing surface of the pair of clamping portions is a flat surface.

5. In the pair of clamping portions, a spacing holding portion for holding the spacing between the pair of clamping portions is provided at a position radially symmetric with respect to the rotation center of the conversion unit with respect to the position where the outer peripheral surface of the output shaft contacts. The diaphragm mechanism according to claim 3 or claim 4.

6. The diaphragm mechanism according to claim 5, wherein the spacing holding portion is a rotating body sandwiched between the pair of clamping portions and rotatable with respect to the pair of clamping portions.

7. The diaphragm mechanism according to claim 6, wherein the rotating body is a sphere.

8. The diaphragm mechanism according to claim 7, wherein at least one of the pair of clamping portions has a concave portion into which a part of the sphere fits.

9. The diaphragm mechanism according to claim 8, wherein the concave portion is a through hole penetrating at least one of the pair of clamping portions.

10. The conversion unit has a biasing portion, The biasing portion applies a biasing force in the facing direction of the pair of clamping portions so as to keep a constant interval with respect to the pair of clamping portions, the aperture mechanism according to claim 8 or 9.

11. The rotation transmission portion has a permanent magnet curved along the circumferential direction with respect to the rotation center, The frame portion has a magnetic force detection element at a position facing the permanent magnet in the optical axis direction, the aperture mechanism according to any one of claims 1 to 10.

12. The aperture plate is supported at an end portion on the side far from the rotation center, the aperture mechanism according to any one of claims 1 to 11.

13. The aperture plate has a long hole extending along a direction perpendicular to the moving direction with respect to the frame portion and the optical axis direction, The end portion of the rotation transmission portion is connected to the long hole, the aperture mechanism according to claim 12.

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