Aperture mechanism

Abstract

An aperture mechanism (A) is provided with: a frame section (1) formed around an optical axis; an aperture plate (2) capable of moving in a direction intersecting the optical axis with respect to the frame section (1) and capable of changing an opening area of the aperture plate in the optical axis direction as the aperture plate moves; and a drive unit (3) for driving the aperture plate (2) to move, the drive unit (3) comprising: an SIDM (31) as a drive source that expands and contracts in a linear direction in response to energization to generate a drive force in the linear direction; a conversion unit (32) that converts a linear driving force of the SIDM (31) into a rotational driving force; and a rotation transmission unit (33) which is connected to the aperture plate (2) in succession with the conversion unit (32), and which rotates with respect to the center of rotation.

Description

Aperture mechanism Technical Field

[0001] The present invention relates to an aperture mechanism, which can be applied to a camera built into information equipment such as a smartphone or a tablet computer. Background Art

[0002] An example of prior art is the aperture mechanism described in Japanese Patent Application Laid-Open No. 2011-90028. This prior art uses a galvanometer as the driving source for moving the aperture plate. Because the galvanometer is composed of a combination of coils, permanent magnets, and springs, miniaturization of the aperture mechanism is difficult, and there is room for improvement when applying this technology to cameras built into information devices.

[0003] Summary of the Invention

[0004] Problems to be solved by the invention

[0005] In view of the above, an object of the present invention is to provide an aperture mechanism that can be reduced in size.

[0006] Solutions for solving problems

[0007] According to one aspect of the present invention, there is provided an aperture mechanism that increases or decreases the area through which light passes in the direction of an optical axis, comprising: a frame formed around the optical axis; an aperture plate that can move relative to the frame in a direction intersecting the optical axis and can change the area of ​​an opening in the direction of the optical axis as the movement occurs; and a drive unit for driving the aperture plate to move, the drive unit comprising: a smooth impact drive mechanism (SIDM) as a drive source that expands and contracts in a linear direction in response to power-on to generate a linear driving force; a conversion unit that converts the linear driving force of the smooth impact drive mechanism into a rotational driving force; and a rotation transmission unit that is continuous with the conversion unit and connected to the aperture plate and performs rotational movement with a rotation center as a reference.

[0008] Furthermore, the combination of the aperture plate and the driving unit pair may be provided as two pairs, which sandwich the optical axis in a direction intersecting the optical axis.

[0009] It can also be configured that the smooth impact drive structure has an output shaft extending along the straight line direction, the conversion part has a pair of clamping parts that are in an opposing relationship in the direction of the optical axis, and the output shaft is clamped by the pair of clamping parts in a manner allowing sliding. In the conversion part, the driving force of the output shaft in the straight line direction is converted into the rotational driving force through the contact between the outer peripheral surface of the output shaft and the pair of clamping parts, so that the rotation transmission part performs the rotational movement.

[0010] It may also be configured that each opposing surface of the pair of clamping parts is a plane.

[0011] A spacing retaining portion for maintaining a spacing between the pair of clamping portions may be provided at a position of the conversion portion that is radially symmetrical with respect to the rotation center relative to a position where the outer peripheral surface of the output shaft contacts the pair of clamping portions.

[0012] The spacing portion may be sandwiched between the pair of sandwiching portions and may be formed of a rotating body rotatable relative to the pair of sandwiching portions.

[0013] The rotating body may also be composed of a sphere.

[0014] At least one of the pair of clamping parts may further include a recessed portion into which a portion of the spherical body is fitted.

[0015] The recessed portion may be formed of a through hole that penetrates at least one of the pair of clamping portions.

[0016] The conversion portion may further include a force applying portion configured to apply force to the pair of clamping portions in the opposing direction of the pair of clamping portions so as to keep the interval constant.

[0017] The rotation transmitting portion may include a permanent magnet curved in a circumferential direction with respect to the rotation center, and the frame portion may further include a magnetic force detecting element at a position facing the permanent magnet in the optical axis direction.

[0018] The aperture plate may be further supported by an end portion located away from the rotation center.

[0019] The aperture plate has a long hole extending in a moving direction relative to the frame portion and in a direction perpendicular to the optical axis direction.

[0020] The end portion of the rotation transmitting portion may be further connected to the long hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 is a perspective view showing a state in which an aperture mechanism, an imaging element, a lens assembly, and a prism are combined according to an embodiment of the present invention.

[0022] FIG. 2 is a front view showing the aperture mechanism.

[0023] FIG3 is a cross-sectional view taken along the arrow line III-III in FIG2 .

[0024] FIG4 is a cross-sectional view taken along the line IV-IV in FIG2 .

[0025] FIG. 5 is an exploded perspective view showing the aperture mechanism.

[0026] FIG. 6 is an exploded perspective view showing a driving portion in the aperture mechanism.

[0027] FIG. 7 is a diagram illustrating the relationship between a driving portion and movement of aperture plates in the aperture mechanism. DETAILED DESCRIPTION

[0028] An aperture mechanism A according to one embodiment of the present invention will be described with reference to the accompanying drawings. Note that the "optical axis" described below is an optical axis passing through the center of each lens in a lens assembly B composed of a plurality of lenses.

[0029] The aperture mechanism A of this embodiment is suitable for use in a camera built into, for example, an information device (e.g., a smartphone, not shown). It is configured to increase or decrease the area through which light passes along the optical axis so that an appropriate amount of light reaches the imaging element C. Figure 1 shows an example of the structure of the aperture mechanism A and its related mechanisms. The vertical direction in Figure 1 coincides with the optical axis direction (the optical axis direction of the aperture mechanism A, lens assembly B, and imaging element C). This optical axis direction is along the front (most often, the side with the screen) and back of the information device, and along either the long or short side. In Figure 1, a prism D, aperture mechanism A, lens assembly B, and imaging element C are assembled in this order, from the incident side of the imaging light. Note that a portion of lens assembly B is overlapped within aperture mechanism A. Prism D refracts imaging light entering from the outside through an opening, such as on the back of the information device, and guides it to the aperture mechanism A. The imaging light that passes through aperture mechanism A passes through lens assembly B and reaches imaging element C. In addition, although not shown in the figure, an autofocus mechanism is also provided for forming an image on imaging element C.

[0030] The aperture mechanism A primarily comprises a frame 1, an aperture plate 2, and a drive unit 3. The shapes and positional relationships of these components are shown in Figures 2 to 5. The frame 1 is the portion formed around the optical axis. In this embodiment, the frame 1 is rectangular when viewed from the optical axis and is flat in the optical axis direction, forming a box-shaped body (specifically, a cuboid). The bottom 11 of the frame 1 (the portion near the lens assembly B) is open in the area around the optical axis and in the portion supporting the conversion unit 32, with the remaining area being closed. A drive substrate 14 is provided in the closed area of ​​the bottom 11. This is electrically connected to the main body of the information device, controls the power supply to the drive unit 3, and receives detection signals related to the operation of the drive unit 3. A flexible substrate is used for the drive substrate 14. Meanwhile, the top 12 (the portion near the prism D) is entirely open, and a cover 16 with a roughly rectangular opening in the center is attached to the outside of the frame 1, closer to the aperture plate 2. This cover 16 prevents imaging light from passing through the frame 1 except for the portion corresponding to the opening of the light-transmitting portion 21 (described later) of the aperture plate 2. Furthermore, the four side portions 13 are closed. Furthermore, the frame 1 only needs to be configured to support at least the aperture plate 2 and the drive unit 3, and its configuration can be varied to suit the shape of the object (such as information equipment) in which the aperture mechanism A is installed. Therefore, a frame-like shape is not essential.

[0031] The aperture plates 2 are arranged to be movable relative to the frame 1 in a direction intersecting the optical axis. In this embodiment, the aperture plates 2 can reciprocate in a direction perpendicular to the optical axis, that is, in a linear direction along the long side of the frame 1. The aperture plates 2 are guided, for example, to the inner surface of the side portion 13 of the frame 1. In the aperture mechanism A, a pair (two) of aperture plates 2, 2 are arranged on the frame 1 so that they partially overlap in the direction of the optical axis. The pair of aperture plates 2, 2 are arranged so that they are aligned with the optical axis when viewed from the optical axis and symmetrically about a line parallel to the short side of the frame 1. The pair of aperture plates 2, 2 are then controlled to move synchronously. That is, during reciprocal movement, one and the other of the pair of aperture plates 2, 2 move the same distance in the linear direction per unit time. Each aperture plate 2 is a rectangular flat plate with a cutout formed inward from the short side. This cutout serves as the light-transmitting portion 21 through which the imaging light passes along the optical axis. The cutout of the light-transmitting portion 21 includes a straight portion along the long side of the rectangle and a beveled portion. The beveled portion is continuous with the straight portion in the interior direction of the rectangle and is inclined linearly relative to the long and short sides. Thus, the light-transmitting portion 21, through the combination of the pair of aperture plates 2, 2, assumes a laterally elongated hexagonal shape (when the aperture is wide) or a diamond shape (when the aperture is narrow) in response to the movement of the aperture plates 2. In Figure 7, solid lines and two-dot chain lines illustrate examples of multiple movement states (openings) for one of the pair of aperture plates 2, 2. The aperture plate 2 can move either continuously or in steps to achieve an opening corresponding to the aperture value (such as the various openings shown in Figure 7).

[0032] The aperture plate 2 is supported by the end portion of the drive unit 3 (the corner of the rectangle / the lower corner in Figure 5) that is distal to the rotation center of the rotation transmission unit 33 (described later). This positional arrangement allows the rotation transmission unit 33 to overlap the aperture plate 2 when viewed along the optical axis, eliminating wasted space within the frame 1 and enabling a compact aperture mechanism A. The aperture plate 2 has an elongated hole 22 that extends in the direction of movement relative to the frame 1 and perpendicular to the optical axis. The end portion of the rotation transmission unit 33 is connected to the elongated hole 22 by inserting a connecting protrusion 332 into the elongated hole 22, thereby enabling power transmission from the rotation transmission unit 33 to the aperture plate 2. The connecting protrusion 332 protrudes parallel to the rotation axis of the rotation transmission unit 33. In this embodiment, as shown in Figure 5, the elongated hole 22 is formed along the short side of the lower corner of the aperture plate 2. The connecting protrusion 332 is cylindrical with a perfect circular cross-section. Because the connecting protrusion 332 is movable within the elongated hole 22, the elongated hole 22 can absorb any positional misalignment between the rotationally moving rotation transmitting portion 33 and the linearly moving aperture plate 2. This allows for smooth conversion of the rotational motion of the rotation transmitting portion 33 into the linear motion of the aperture plate 2. As the aperture plate 2 configured as described above moves relative to the frame 1, the aperture area of ​​the aperture in the direction of the optical axis changes through the light-transmitting portion 21 of the pair of aperture plates 2, 2. In this embodiment, since the pair of aperture plates 2 are arranged so as to move about the optical axis, the aperture area of ​​the axial opening can be rapidly changed.

[0033] The drive unit 3 is responsible for driving the aperture plates 2. As shown in Figure 5 , two pairs of aperture plates 2 and drive units 3 are provided, sandwiching the optical axis in a direction intersecting (specifically, orthogonal to) the optical axis. As shown in Figure 6 , the drive unit 3 comprises a smooth impact drive mechanism (SIDM) 31 as the drive source, a conversion unit 32, and a rotation transmission unit 33.

[0034] The SIDM 31 generates a linear driving force by expanding and contracting in the linear direction in response to power supply. Since the SIDM itself is a well-known device, only a brief description will be given. The SIDM 31 has an output shaft 311 extending in the direction of the driving force, i.e., the linear direction. The output shaft 311 is a straight rod, for example, a straight rod made of carbon fiber reinforced plastic (CFRP). A piezoelectric element 312 and a weight 313 that are integral with the output shaft 311 are provided at one axial end of the output shaft 311 (the end near the end of the frame 1). As shown in Figure 2, the weight 313 of the SIDM 31 is fixed to the inner surface of the frame 1 by bonding or other methods. Power is supplied to the piezoelectric element 312 from the drive substrate 14. The piezoelectric element 312 expands and contracts in the axial direction due to power supply. That is, the piezoelectric element 312 mode is the d33 mode. By adjusting the energized state, relative to slowly extending the piezoelectric element 312, it is shortened sharply, or, relative to sharply extending, it is shortened slowly, that is, for the object (converter 32 in the present embodiment) to which the driving force is transmitted, by setting a difference between the extension and the shortening, the peripheral portion of the output shaft 311 can transmit a driving force in a straight line toward one direction through friction. By changing the extension and shortening of the piezoelectric element 312, the transmission direction of the driving force can be determined. It should be noted that the energization of SIDM31 is not continuous, but is carried out intermittently during the extension or shortening. Therefore, the power consumption for driving can be suppressed. In addition, it can be energized when extending or shortening, or it can be energized only when it is sharply deformed.

[0035] The conversion section 32 is a portion that converts the linear driving force generated by the SIDM 31 into a rotational driving force. In the conversion section 32, a cylindrical support portion 323 is rotatably supported on the bottom 11 of the frame 1. The configuration is such that a sphere is provided in the portion supporting the support portion 323 in the frame 1 so that the conversion section 32 can rotate smoothly. The conversion section 32 has a pair of clamping sections 321, 321 that are in an opposing relationship in the optical axis direction. The pair of clamping sections 321, 321 are integrated by concave and convex fitting, as shown in Figures 3 or 6, and can therefore rotate as a whole. The clamping section 321 is in the shape of a circular plate. Therefore, the opposing surfaces 3211 of the pair of clamping sections 321, 321 are flat. The output shaft 311 of the SIDM 31 contacts the pair of clamping sections 321, 321 (the opposing surfaces 3211 facing inward, respectively) in a manner that generates friction and is clamped in a manner that allows sliding. Friction acts in the axial direction of the output shaft 311. Sliding occurs in the circumferential direction of the clamping portion 321. The configuration of the SIDM 31 relative to the conversion portion 32 is such that the circumferential direction (or tangential direction) of the clamping portion 321 is along the axial relationship of the output shaft 311. Therefore, the driving force of the SIDM 31 in the linear direction is transmitted to the clamping portion 321 as a force in the circumferential direction through the friction acting between the output shaft 311 and the clamping portion 321. This transmitted force is a rotational driving force, so the direction of the force between the output shaft 311 of the SIDM 31 and the clamping portion 321 of the conversion portion 32 is converted from a linear direction to a rotational direction. In this embodiment, since the clamping portion 321 contacts the output shaft 311 in a plane, the contact area between the output shaft 311 and the pair of clamping portions 321, 321 can be kept fixed regardless of the rotation angle of the conversion portion 32, thereby enabling stable conversion of the driving force. As described above, in the conversion unit 32, the linear driving force of the output shaft 311 is converted into rotational driving force through the contact between the outer peripheral surface of the output shaft 311 and the pair of clamping parts 321, 321, thereby rotating the rotation transmission unit 33. This configuration has the advantage of simplifying the structure for converting the linear driving force generated by the SIDM 31 into rotational driving force. Furthermore, when the conversion unit 32 is stopped, the position is maintained by friction between the output shaft 311 of the SIDM 31 and the clamping parts 321, eliminating the need for power to maintain the position.

[0036] In the pair of clamping portions 321, 321, a spacing portion 3212 is provided at positions on the converter 32 that are radially symmetrical (180 degrees apart in the circumferential direction) with respect to the position where the pair of clamping portions 321, 321 contact the outer circumferential surface of the output shaft 311 of the SIDM 31. This spacing portion maintains the spacing between the pair of clamping portions 321, 321. Spacer holding portions 3212, combined with the output shaft 311, maintain a constant distance in the opposing direction between the pair of clamping portions 321, 321, thereby stably transmitting the driving force of the output shaft 311 to the converter 32. Spacer holding portions 3212 are rotating bodies that are clamped between the pair of clamping portions 321, 321 and are rotatable relative to the pair of clamping portions 321, 321. Because spacer holding portions 3212 are rotating bodies, even if the pair of clamping portions 321, 321 are displaced in the rotational direction, this spacing portion 3212 is not affected. Specifically, the spacer holding portion 3212 is a sphere with a perfect circular cross-section, for example, a metal ball or a ceramic ball can be used. By setting it as a sphere, a rotatable rotating body can be easily formed, and a general-purpose product can be used. The spacer holding portion 3212 can rotate in all directions. Corresponding to the spacer holding portion 3212, at least one of the pair of clamping portions 321, 321 has a recess 3213 for embedding a part of the sphere. Through the recess 3213, the spacer holding portion 3212, which is a sphere, can be maintained in a fixed position in the clamping portion 321. In this embodiment, the recess 3213 is a through hole that passes through the clamping portion 321 in the thickness direction, and the spacer holding portion 3212, which is a sphere, is embedded therein in a rotatable state. By setting it as a through hole, the recess 3213 can be formed more easily than when it is set with a bottom. By combining it with the recess 3213, the spacer holding portion 3212 is rotatably supported in a fixed position in the clamping portion 321. In this manner, the contact points of the output shaft 311 of the SIDM 31 and the spacing portions 3212 of the pair of clamping portions 321, 321 are arranged at radially symmetrical positions. Consequently, the distance between the pair of clamping portions 321, 321 in the opposing direction remains constant. Consequently, the frictional force associated with contact between the output shaft 311 of the SIDM 31 and the clamping portions 321 can be kept constant, allowing for stable transmission of the driving force of the output shaft 311 to the conversion portion 32.

[0037] The conversion portion 32 has a force-applying portion 322. The force-applying portion 322 applies force to a pair of clamping portions 321, 321 in opposite directions of the pair of clamping portions 321, 321 to maintain a fixed interval. Through the force-applying portion 322, the degree of contact between the output shaft 311 of the SIDM31 and the pair of clamping portions 321, 321 can be kept constant, while also preventing the interval-maintaining portion 3212, which is a sphere, from falling off from the recess 3213. In this embodiment, a coil spring serving as a compression spring is used as the force-applying portion 322. The force-applying portion 322 is wound around the shaft of a connecting component 324 serving as a screw. The connecting component 324 is threadedly fixed to the clamping portion 321 on the opposite side of the force-applying portion 322, and can move axially relative to the clamping portion 321 on the side in contact with the force-applying portion 322. The spring force reacts against the clamping portion 321 on the side in contact with the biasing portion 322 (coil spring) to bias the clamping portion 321 on the opposite side (opposite side) so as to attract the clamping portion 321. This biasing force keeps the gap between the pair of clamping portions 321, 321 narrow.

[0038] The rotation transmission unit 33 and the conversion unit 32 are connected to and rotated around the aperture plate 2, moving about the rotation center. The rotation center is not located within the rotation transmission unit 33 itself, but rather within the clamping portion 321 of the conversion unit 32. The rotation center extends parallel to the optical axis. In this embodiment, an arm-shaped portion 331 radially extends from the disc-shaped clamping portion 321 of the pair of conversion units 32, located on the top 12 side of the frame 1. This arm-shaped portion 331 is integrally formed with the clamping portion 321, forming a single flat plate. The rotation transmission unit 33 includes a connecting protrusion 332 that connects to the aperture plate 2. The rotation transmission unit 33 with the arm-shaped portion 331 can adjust the distance of movement of the connecting protrusion 332 during the output of driving force from the SIDM 31 based on the ratio between the radial distance from the conversion unit 32's rotation center to the contact point with the output shaft 311 of the SIDM 31 and the distance from the rotation center to the connecting protrusion 332. Therefore, the movement distance of the aperture plate 2 of the frame 1 can be adjusted, and a desired output (ie, movement distance) can be set.

[0039] The rotation transmission unit 33 includes a permanent magnet 333 that is curved in a circumferential direction relative to the rotation center of the conversion unit 32. The permanent magnet 333 is configured so that one pole (e.g., the north pole) is located on one side of the rotation transmission unit 33 in the circumferential direction, and the other pole (e.g., the south pole) is located on the other side. Accordingly, the frame 1 includes a magnetic force detection element 15 at a position opposite the permanent magnet 333 in the optical axis direction. The magnetic force detection element 15 can be, for example, a Hall element or an MR element. 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 on the application object (information equipment) of the aperture mechanism A. Based on the detection result, the control unit controls the drive unit 3 (specifically, the power supply of the SIDM 31). Through this combination of the permanent magnet 333 and the magnetic force detection element 15, the rotation state of the rotation transmission unit 33 can be detected.

[0040] As described above, this embodiment provides an aperture mechanism A that increases or decreases the area through which light passes in the direction of the optical axis. The mechanism comprises: a frame 1 formed around the optical axis; an aperture plate 2 movable relative to the frame 1 in a direction intersecting the optical axis, capable of varying the area of ​​the aperture opening in the direction of the optical axis as it moves; and a drive unit 3 for driving the aperture plate 2. The drive unit 3 includes: an SIDM 31 serving as a drive source, which linearly expands and contracts in response to power supply to generate a linear driving force; a conversion unit 32 that converts the linear driving force of the SIDM 31 into a rotational driving force; and a rotation transmission unit 33 connected to the conversion unit 32 and to the aperture plate 2, rotating the aperture plate 2 about its rotational center. This configuration utilizes the SIDM 31, enabling the conversion unit 32 and rotation transmission unit 33 to move the aperture plate 2, thereby achieving a compact aperture mechanism A.

[0041] Furthermore, two pairs of aperture plates 2 and drive units 3 are provided, sandwiching the optical axis in a direction intersecting the optical axis. This configuration allows the aperture plates 2 of the two pairs to move while sandwiching the optical axis, enabling rapid changes in the axial aperture area.

[0042] Furthermore, the SIDM 31 includes an output shaft 311 extending in the linear direction, and the conversion section 32 includes a pair of clamping sections 321, 321 that are opposed to each other in the optical axis direction. The output shaft 311 is slidably clamped by the pair of clamping sections 321, 321. The conversion section 32 can also be configured to convert the linear driving force of the output shaft 311 into the rotational driving force through contact between the outer peripheral surface of the output shaft 311 and the pair of clamping sections 321, 321, thereby causing the rotation transmitting section 33 to perform the rotational movement. This configuration can simplify the structure for converting the linear driving force generated by the SIDM 31 into the rotational driving force.

[0043] In addition, the opposing surfaces 3211 of the pair of clamping parts 321, 321 can also be configured as flat surfaces. According to this structure, by contacting with the flat surfaces, the contact area between the output shaft 311 of the SIDM 31 and the pair of clamping parts 321, 321 can be kept constant regardless of the rotation angle of the conversion part 32, thereby stably converting the driving force.

[0044] Furthermore, spacing portions 3212 for maintaining a spacing between the pair of clamping portions 321, 321 may be provided at positions on the conversion portion 32 that are radially symmetrical about the rotation center relative to the positions where the pair of clamping portions 321, 321 contact the outer circumferential surface of the output shaft 311. This configuration maintains a constant distance between the pair of clamping portions 321, 321 in the opposing direction by the spacing portions 3212, thereby enabling stable transmission of the driving force of the output shaft 311 to the conversion portion 32.

[0045] Alternatively, the spacer 3212 is held between the pair of clamping portions 321, 321 and may be formed of a rotating body rotatable relative to the pair of clamping portions 321, 321. With this configuration, since the spacer 3212 is a rotating body, even if the pair of clamping portions 321, 321 are displaced in the rotational direction, the spacer 3212 is not affected.

[0046] In addition, the rotating body may be formed of a sphere. According to this structure, a rotatable rotating body can be easily formed.

[0047] At least one of the pair of clamping parts 321, 321 may further include a recess 3213 for a portion of the sphere to fit in. With this configuration, the recess 3213 can hold the sphere-shaped spacer 3212 at a fixed position in the clamping part 321.

[0048] Alternatively, the recess 3213 may be formed of a through hole that penetrates at least one of the pair of clamping portions 321, 321. With this configuration, the recess 3213 can be easily formed.

[0049] Furthermore, the conversion portion 32 includes a force applying portion 322 that is configured to maintain a fixed spacing relative to the pair of clamping portions 321, 321 so as to apply force in the opposing directions of the pair of clamping portions 321, 321. This configuration maintains a constant degree of contact between the output shaft 311 of the SIDM 31 and the pair of clamping portions 321, 321, while also preventing the spherical spacer 3212 from falling out of the recess 3213.

[0050] Furthermore, the rotation transmitting portion 33 includes a permanent magnet 333 that is curved in a circumferential direction about the rotation center, and the frame portion 1 may further include a magnetic force detection element 15 at a position opposite to the permanent magnet 333 in the optical axis direction. With this configuration, the combination of the permanent magnet 333 and the magnetic force detection element 15 enables the rotation state of the rotation transmitting portion 33 to be detected.

[0051] In addition, the aperture plate 2 can be supported by its end portion away from the rotation center. With this configuration, the rotation transmitting portion 33 can be arranged to overlap the aperture plate 2 when viewed in the optical axis direction, thereby making the aperture mechanism A compact.

[0052] Furthermore, the aperture plate 2 has an elongated hole 22 extending in the direction of movement relative to the frame 1 and in a direction orthogonal to the optical axis, and the end portion of the rotation transmitting portion 33 may be connected to the elongated hole 22. With this configuration, since positional misalignment between the rotation transmitting portion 33 and the aperture plate 2 can be absorbed by the elongated hole 22, the rotational motion of the rotation transmitting portion 33 can be smoothly converted into linear motion of the aperture plate 2.

[0053] According to the aperture mechanism A of this embodiment, a compact structure is achieved by using the SIDM 31 to move the aperture plate 2 via the conversion unit 32 and the rotation transmission unit 33. This allows for miniaturization of the aperture mechanism A. This miniaturization allows existing smartphones to be thinner and can also be used in built-in cameras in foldable smartphones.

[0054] Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and appropriate design changes can be made within the scope of the present invention. In addition, the effects of the present invention are not limited to the contents described in the embodiments. That is, all aspects of the embodiments disclosed this time are merely examples and do not limit the present invention. The scope of the present invention is limited by the scope of the claims rather than the above description. In addition, the scope of the present invention is intended to include the same meaning as the claims, and all changes within the scope.

[0055] For example, while the aperture mechanism A of this embodiment has been described as being applicable to cameras built into information devices (e.g., smartphones), the invention is not limited thereto. It can also be applied to single-function cameras or incorporated into other devices (e.g., in-vehicle devices such as navigation systems, home appliances such as air conditioners, and intercoms). Furthermore, the aperture mechanism A can also be incorporated into optical devices other than cameras.

[0056] In the above embodiment, the aperture plate 2 is formed of two plates in a pair, but may also be formed of a single plate or three or more plates. Even when formed of two plates, a single aperture plate 2 may be immovably fixed to the frame 1.

[0057] Furthermore, the drive unit 3 may be configured as a single set of drive units 3 (particularly the SIDM 31 and the conversion unit 32 ), with the drive force divided by the rotation transmission unit 33 , and the pair of (two) aperture plates 2 , 2 moved by the divided drive force.

[0058] Furthermore, regarding the conversion unit 32, the clamping portion 321 is disk-shaped in the aforementioned embodiment, but is not limited thereto. For example, it may also be fan-shaped to correspond to the range of rotational movement. Furthermore, the frictional contact between the output shaft 311 of the SIDM 31 and the clamping portion 321 may be direct, or a separate sheet-like member may be interposed between the output shaft 311 and the clamping portion 321. Furthermore, the outer circumferential surface of the output shaft 311 or the opposing surface 3211 of the clamping portion 321 may be coated or processed with relief to adjust friction.

[0059] Furthermore, the rotation transmission unit 33 is constituted by the arm portion 331 in the above embodiment, but may be provided with various structures for transmitting the driving force from the driving unit 3 and the conversion unit 32 to the aperture plate 2 .

[0060] Explanation of the accompanying drawings: 1. Frame; 11. Bottom of the frame; 12. Top of the frame; 13. Side of the frame; 14. Drive substrate; 15. Magnetic detection element; 16. Cover; 2. Aperture plate; 21. Light-transmitting portion; 22. Long hole; 3. Drive portion; 31. SIDM; 311. Output shaft; 312. Piezoelectric element; 313. Counterweight; 32. Converter; 321. Clamping portion; 3211. Opposing surface; 3212. Spacing maintaining portion; 3213. Recessed portion; 322. Force-applying portion; 323. Support portion; 324. Connecting component; 33. Rotation transmission portion; 331. Arm-shaped portion; 332. Connecting protrusion; 333. Permanent magnet; A. Aperture mechanism; B. Lens assembly; C. Shooting element; D. Prism.

Claims

1. An aperture mechanism that increases or decreases the area through which light passes in the direction of an optical axis, the aperture mechanism comprising: a frame portion formed around the optical axis; an aperture plate that is movable relative to the frame in a direction intersecting the optical axis and that is capable of changing an opening area opened in the direction of the optical axis as the movement occurs; as well as, a driving unit, which is used to drive the aperture plate to move, The driving unit comprises: A smooth impact drive structure as a drive source, which expands and contracts in a linear direction in response to power supply to generate a driving force in the linear direction; a conversion portion that converts the linear driving force of the smooth impact driving structure into a rotational driving force; and The rotation transmission part is connected to the conversion part and the aperture plate, and performs rotational movement based on the rotation center.

2. The aperture mechanism according to claim 1, wherein: The combination of the aperture plate and the driving unit is provided in pairs, and sandwiches the optical axis in a direction intersecting the optical axis.

3. The aperture mechanism according to claim 1 or 2, wherein: The smooth impact drive structure has an output shaft extending along the straight direction, The conversion portion includes a pair of clamping portions that are in an opposing relationship in the optical axis direction. The output shaft is clamped by the pair of clamping parts in a manner allowing sliding. In the conversion portion, the linear driving force of 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 transmitting portion performs the rotational movement.

4. The aperture mechanism according to claim 3, wherein: Each opposing surface of the pair of clamping parts is a plane.

5. The aperture mechanism according to claim 3 or 4, wherein: In the pair of clamping parts, spacing maintaining parts for maintaining a spacing between the pair of clamping parts are provided at positions of the conversion part that are radially symmetrical with respect to the rotation center with respect to positions where the outer peripheral surface of the output shaft contacts.

6. The aperture mechanism according to claim 5, wherein: The spacing holding portion is a rotating body, and the rotating body is sandwiched between the pair of sandwiching portions and is rotatable relative to the pair of sandwiching portions.

7. The aperture mechanism according to claim 6, wherein: The rotating body is a sphere.

8. The aperture mechanism according to claim 7, wherein: At least one of the pair of clamping parts has a recessed portion into which a part of the spherical body is inserted.

9. The aperture mechanism according to claim 8, wherein: The recessed portion is a through hole that penetrates at least one of the pair of clamping portions.

10. The aperture mechanism according to claim 8 or 9, wherein: The conversion part has a force applying part, The force applying portion applies force to the pair of clamping portions in the opposing direction of the pair of clamping portions so as to keep the interval between them constant.

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

12. The aperture mechanism according to any one of claims 1 to 11, wherein: The aperture plate is supported by an end portion on a side away from the rotation center.

13. The aperture mechanism according to claim 12, wherein: The aperture plate has a long hole extending in a moving direction relative to the frame portion and in a direction orthogonal to the optical axis direction. The end portion of the rotation transmitting portion is connected to the long hole.

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