Blade drive device and imaging device equipped therewith

Abstract

To provide a blade driving device that can open and close an opening at a high speed.SOLUTION: A blade driving device 1 comprises: a bottom board 10 that is provided with an opening S; blades 21-24 that are movable between closed positions and open positions; a rotational driving member 50 that has a driving pin 54 connected to the blades 21, 22 and a gear part 55 provided with a plurality of teeth along a circumferential direction, and can rotate around a driving shaft 15 to move the blades 21, 22; a rotational driving member 60 that has a driving pin 64 connected to the blades 23, 24 and a gear part 65 provided with a plurality of teeth along the circumferential direction, the plurality of teeth meshing with the teeth of the gear part 55 of the rotational driving member 50, and can rotate around a driving shaft 16 to move the blades 23, 24; and an electromagnetic coil unit 80 that rotates the rotational driving member 50.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a blade drive device and an imaging device provided with the same, and particularly to a blade drive device used as a shutter in a digital camera or the like.

Background Art

[0002] In a digital camera or the like, a blade drive mechanism is often provided that moves one or more shutter blades connected to a drive lever in one direction by rotating the drive lever, and opens and closes an exposure aperture with these shutter blades (see, for example, Patent Document 1). In recent years, a faster shutter operation has been demanded, and a blade drive mechanism that can open and close the exposure aperture at a higher speed has been desired.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention has been made in view of such problems of the prior art, and an object thereof is to provide a blade drive device capable of opening and closing an aperture at high speed.

Means for Solving the Problems

[0005] According to one aspect of the present invention, a blade drive device capable of opening and closing an opening at high speed is provided. This blade drive device comprises a base plate in which an opening is formed, at least one first blade movable between a first closed position that covers a part of the opening and a first open position that retracts to the outside of the opening, at least one second blade movable between a second closed position that covers a part of the opening and a second open position that retracts to the outside of the opening, a first connecting part connected to the at least one first blade, and a first gear part having a plurality of teeth formed along the circumferential direction, and the at least one first blade rotates around a first drive shaft. The device comprises a first rotary drive member capable of moving the first blade between the first closed position and the first open position; a second rotary drive member having a second connecting portion connected to the at least one second blade and a second gear portion having a plurality of teeth formed circumferentially that mesh with the teeth of the first gear portion of the first rotary drive member, and capable of moving the at least one second blade between the second closed position and the second open position by rotating around a second drive shaft; and a drive unit that rotates the first rotary drive member.

[0006] According to a second aspect of the present invention, an imaging device is provided comprising the above-mentioned blade drive device and an image sensor arranged on a surface in which light transmitted through the blade drive device forms an image. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a perspective view showing a blade drive device in one embodiment of the present invention. [Figure 2] Figure 2 is an exploded perspective view of the blade drive device shown in Figure 1. [Figure 3] Figure 3 is a front view showing the base plate in the blade drive device shown in Figure 1. [Figure 4] Figure 4 is a perspective view of the rotational drive member in the blade drive device shown in Figure 2. [Figure 5] Figure 5 is a perspective view of the rotational drive member in the blade drive device shown in Figure 2. [Figure 6]Figure 6 is a perspective view of the braking member in the blade drive device shown in Figure 2. [Figure 7] Figure 7 is a perspective view of the brake pad in the vane drive device shown in Figure 2. [Figure 8A] Figure 8A is a schematic plan view showing the blades in the closed position of the blade drive device shown in Figure 1. [Figure 8B] Figure 8B is a schematic plan view showing the blades in the open position in the blade drive device shown in Figure 1. [Figure 9A] Figure 9A is a schematic front view showing the state of the rotary drive member just before it moves from the first rotation position shown in Figure 8A to the second rotation position shown in Figure 8B. [Figure 9B] Figure 9B is a schematic front view showing the state in which the rotary drive member has rotated from the state shown in Figure 9A to the second rotation position. [Figure 9C] Figure 9C is a schematic front view showing the state of the rotary drive member just before it moves from the second rotational position shown in Figure 8B to the first rotational position. [Figure 9D] Figure 9D is a schematic front view showing the state in which the rotary drive member has rotated from the state shown in Figure 9C to the first rotation position. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of the blade drive device and imaging device according to the present invention will be described in detail with reference to Figures 1 to 9D. In Figures 1 to 9D, identical or corresponding components are denoted by the same reference numerals, and redundant descriptions are omitted. Also, in Figures 1 to 9D, the scale and dimensions of each component may be exaggerated, or some components may be omitted. In the following description, unless otherwise specified, terms such as "first" and "second" are used only to distinguish components from each other and do not represent a specific rank or order.

[0009] Figure 1 is a perspective view showing a blade drive device 1 in one embodiment of the present invention, and Figure 2 is an exploded perspective view. In this embodiment, the blade drive device 1 is described as a shutter device incorporated into an optical device such as a camera, but this is merely an example, and the blade drive device according to the present invention is not limited to such shutter devices.

[0010] As shown in Figures 1 and 2, the blade drive device 1 in this embodiment includes a base plate 10 with a rectangular opening (exposed opening) S formed therein, blades 21-24 housed in the space formed between the base plate 10 and a cover (not shown), blade arms 31 and 32 connected to blades 21 and 22 (first blades), and blade arms 33 and 34 connected to blades 23 and 24 (second blades). This blade drive device 1 is incorporated into an imaging device equipped with an image sensor (not shown) such as a CCD or CMOS sensor, with the +Z direction being the subject side. Light from the subject passes through the opening S in the base plate 10 and is incident on the image sensor located on the -Z direction side of the blade drive device 1. Depending on the camera configuration, the -Z direction may be the subject side and the +Z direction may be the image sensor side.

[0011] Each of the blades 21-24 is a thin, plate-like member that extends in the X direction as a whole. Blades 21 and 22 are stacked in the -Z direction, and blades 23 and 24 are also stacked in the -Z direction. Blade 21 is connected to blade arms 31 and 32 by pins 41 and 42, respectively, and blade 22 is connected to blade arms 31 and 32 by pins 43 and 44, respectively. Blade 23 is connected to blade arms 33 and 34 by pins 45 and 46, respectively, and blade 24 is connected to blade arms 33 and 34 by pins 47 and 48, respectively.

[0012] A circular hole 311 is formed at the end of the blade arm 31, and a substantially rectangular lever connection hole 312 is formed at a position slightly separated from the circular hole 311. A pin 313 is inserted into the circular hole 311 of the blade arm 31, and the pin 313 inserted into the circular hole 311 is press-fitted into a pin hole (not shown) formed in the floor 10. Thereby, the blade arm 31 is configured to be rotatable about the pin 313.

[0013] Also, a circular hole 321 is formed at the end of the blade arm 32. A pin 323 is inserted into the circular hole 321 of the blade arm 32, and the pin 323 inserted into the circular hole 321 is press-fitted into a pin hole (not shown) formed in the floor 10. Thereby, the blade arm 32 is configured to be rotatable about the pin 323.

[0014] Thus, a link mechanism is constituted by the blades 21, 22 and the blade arms 31, 32. That is, when the blade arm 31 rotates about the pin 313 and the blade arm 32 rotates about the pin 323, the blades 21, 22 move mainly in the Y direction while changing the overlapping region with each other by the link mechanism.

[0015] A circular hole 331 is formed at the end of the blade arm 33, and a substantially rectangular lever connection hole 332 is formed at a position slightly separated from the circular hole 331. The end of a drive shaft 16 described later is inserted into the circular hole 331 of the blade arm 33, and the blade arm 33 is configured to be rotatable about the drive shaft 16.

[0016] Also, a circular hole 341 is formed at the end of the blade arm 34. A pin 343 is inserted into the circular hole 341 of the blade arm 34, and the pin 343 inserted into the circular hole 341 is press-fitted into a pin hole (not shown) formed in the floor 10. Thereby, the blade arm 34 is configured to be rotatable about the pin 343.

[0017] Thus, a link mechanism is constituted by the blades 23, 24 and the blade arms 33, 34. That is, when the blade arm 33 rotates about the drive shaft 16 and the blade arm 34 rotates about the pin 343, the link mechanism changes the overlapping region of the blades 23, 24 with each other and mainly moves in the Y direction.

[0018] FIG. 3 is a front view showing the floor 10. As shown in FIG. 3, the floor 10 has a cylindrical shaft portion 12 with a circular hole 11 formed in the center and a cylindrical shaft portion 14 with a circular hole 13 formed in the center. Further, arc grooves 17 along an arc centered on the circular hole 11 and arc grooves 18 along an arc centered on the circular hole 13 are formed in the floor 10. As shown in FIG. 2, a drive shaft 15 extending in the Z direction is inserted and fixed into the circular hole 11 of the shaft portion 12. This drive shaft 15 is arranged coaxially with the pin 313 that pivotally supports the blade arm 31. Further, a drive shaft 16 extending in the Z direction is inserted and fixed into the circular hole 13 of the shaft portion 14.

[0019] As shown in FIGS. 1 and 2, the blade driving device 1 includes an electromagnetic coil unit 80, a rotation driving member 50 (first rotation driving member) rotationally driven by the electromagnetic coil unit 80, and a rotation driving member 60 (second rotation driving member) that rotates in conjunction with the rotation of the rotation driving member 50.

[0020] FIG. 4 is a perspective view of the rotation driving member 50. As shown in FIG. 4, the rotation driving member 50 has a shaft portion 51 in which an insertion hole 51A through which the drive shaft 15 is inserted is formed, a rotor 52 fixed to the end portion on the +Z direction side of the shaft portion 51, an arm portion 53 extending radially outward from the shaft portion 51, a drive pin 54 (first connecting portion) extending in the -Z direction from the end portion of the arm portion 53, and a gear portion 55 (first gear portion) having a plurality of teeth formed along the circumferential direction on the outer peripheral portion of the shaft portion 51.

[0021] The rotor 52 is composed of permanent magnets magnetized with different magnetic poles 52A and 52B in the diametrical direction. For example, magnetic pole 52A is the south pole and magnetic pole 52B is the north pole. The rotational drive member 50 is rotatably mounted on a drive shaft 15 which is installed in a circular hole 11 in the base plate 10.

[0022] The drive pin 54 of the rotary drive member 50 is configured to protrude in the -Z direction through the arc groove 17 of the base plate 10. This drive pin 54 protruding in the -Z direction is fitted snugly into the lever connecting hole 312 of the blade arm 31, and the rotary drive member 50 and the blade arm 31 are connected by the drive pin 54. As a result, when the rotary drive member 50 rotates around the drive shaft 15, the drive pin 54 moves within the arc groove 17 of the base plate 10, causing the blade arm 31 to rotate around the pin 313. The arm portion 53 of the rotary drive member 50 is capable of contacting the ends on both sides of the arc groove 17 of the base plate 10.

[0023] Returning to Figure 2, the electromagnetic coil unit 80 includes four metal yokes 81A, 81B, 82A, and 82B, two bobbins 83A and 83B, and two coils 84 wound around each bobbin 83A and 83B. The coils 84 are connected to a control unit (not shown), which controls the energization of the coils 84. This electromagnetic coil unit 80 and the rotor 52 of the rotary drive member 50 constitute a motor (drive unit) that rotates the rotary drive member 50 around the drive shaft 15.

[0024] Yokes 81A and 81B are arranged overlapping in the Z direction, and yokes 82A and 82B are arranged overlapping in the Z direction. Yokes 81A, 81B and yokes 82A, 82B are arranged opposite each other in the X direction, surrounding the rotor 52 of the rotary drive member 50. The ends of each yoke 81A, 81B, 82A, and 82B are inserted into the hollow parts of bobbins 83A and 83B. In the hollow part of bobbin 83A, yokes 81B and 82A are arranged overlapping in the Z direction, and in the hollow part of bobbin 83B, yokes 81A and 82B are arranged overlapping in the Z direction.

[0025] Figure 5 is a perspective view of the rotary drive member 60. As shown in Figure 5, the rotary drive member 60 has a shaft portion 61 through which a drive shaft 16 is inserted, an arm portion 63 extending radially outward from the shaft portion 61, a drive pin 64 (second connecting portion) extending in the -Z direction from the end of the arm portion 63, a gear portion 65 (second gear portion) having a plurality of teeth formed circumferentially on the outer circumference of the shaft portion 61, a pusher 66 protruding circumferentially from the arm portion 63, and a pusher 67 extending radially outward from the shaft portion 61. The teeth of the gear portion 65 of the rotary drive member 60 are configured to mesh with the teeth of the gear portion 55 of the rotary drive member 50.

[0026] The rotary drive member 60 is rotatably mounted on a drive shaft 16 that is attached to a circular hole 13 in the base plate 10. The end of the drive shaft 16 on the -Z direction side protrudes from the base plate 10 in the -Z direction through the circular hole 13 in the base plate 10. The end of the drive shaft 16 that protrudes from the base plate 10 in the -Z direction is inserted into a circular hole 331 in the blade arm 33.

[0027] The drive pin 64 of the rotary drive member 60 is configured to protrude in the -Z direction through the arc groove 18 of the base plate 10. This drive pin 64 protruding in the -Z direction is fitted snugly into the lever connecting hole 332 of the blade arm 33, and the rotary drive member 60 and the blade arm 33 are connected by the drive pin 64. As a result, when the rotary drive member 60 rotates around the drive shaft 16, the drive pin 64 moves within the arc groove 18 of the base plate 10, causing the blade arm 33 to rotate around the drive shaft 16. The arm portion 63 of the rotary drive member 60 can contact the ends on both sides of the arc groove 18 of the base plate 10.

[0028] Returning to Figure 2, a braking member 90 that can rotate around the shaft portion 14 is attached to the shaft portion 14 of the base plate 10. A brake pad 120 (sliding contact member) is positioned adjacent to the braking member 90. The base plate 10 has a spring receiving portion 101 on the +Y direction side of the brake pad 120, and a coil spring 110 (biasing member) is loaded in a compressed state between this spring receiving portion 101 and the brake pad 120. The biasing force of this coil spring 110 presses the brake pad 120 toward the braking member 90.

[0029] Figure 6 is a perspective view of the braking member 90. As shown in Figure 6, the braking member 90 has a ring portion 92 into which a circular hole 91 is formed into which the shaft portion 14 of the base plate 10 is inserted, a stopper piece 93 extending outward from the ring portion 92, and a brake piece 94 having a greater thickness in the Z direction than the ring portion 92. The outer circumferential surface 94A of the brake piece 94 is formed from a part of a cylindrical surface. One side surface 95 of the brake piece 94 is capable of contacting the pusher 66 (first pusher) of the rotary drive member 60, and the other side surface 96 is capable of contacting the pusher 67 (second pusher) of the rotary drive member 60.

[0030] Figure 7 is a perspective view of the brake pad 120. As shown in Figure 7, the brake pad 120 has a pad body 121 having a sliding contact surface 121A that slides against the outer circumferential surface 94A of the brake piece 94 of the braking member 90, and a spring receiving portion 122 that receives the coil spring 110. The sliding contact surface 121A is made up of a part of a cylindrical surface having the same diameter as the cylindrical surface that constitutes the outer circumferential surface 94A of the brake piece 94.

[0031] It is preferable that the braking member 90 and the brake pad 120 are formed from a combination of materials that easily generate frictional force when they come into contact. For example, one of the braking member 90 and the brake pad 120 can be made of acetal and the other of nylon.

[0032] The blades 21-24 are movable between the positions shown in Figure 8A and Figure 8B. In the state shown in Figure 8A, blades 21 and 22 block approximately the lower half of the opening S in the base plate 10, and blades 23 and 24 block approximately the upper half of the opening S in the base plate 10. Blades 21 and 24 overlap in the Z direction, and blades 21-24 as a whole block the opening S in the base plate 10. On the other hand, in the state shown in Figure 8B, blades 21 and 22 are retracted downward (towards the -Y direction) from the opening S in the base plate 10, and blades 23 and 24 are retracted upward (towards the +Y direction) from the opening S in the base plate 10, and the opening S is open.

[0033] In the state shown in Figure 8A, the positions of blades 21 and 22 are referred to as the "first closed position" or simply the "closed position," and the positions of blades 23 and 24 are referred to as the "second closed position" or simply the "closed position." In the state shown in Figure 8B, the positions of blades 21 and 22 are referred to as the "first open position" or simply the "open position," and the positions of blades 23 and 24 are referred to as the "second open position" or simply the "open position."

[0034] Generally, the operation of a camera's blade drive mechanism can be divided into two types: normally closed operation, where the blades are initially closed to the exposure aperture, and the blades immediately activate when the release button is pressed for shooting; and normally open operation, where the blades are initially open to the exposure aperture, and the blades only activate after the release button is pressed, at the final stage of shooting. The blade drive mechanism 1 in this embodiment can handle either operation, but here we will describe the case where normally closed operation is performed.

[0035] In the normally closed operation, when the release button (not shown) is pressed, the vanes 21-24 move from the closed position shown in Figure 8A to the open position shown in Figure 8B. In the state shown in Figure 8A, the rotary drive member 50 is in the position rotated to its maximum extent counterclockwise, and the arm portion 53 of the rotary drive member 50 is in contact with the +Y direction end of the arc groove 17 of the base plate 10. At this time, the coil 84 of the electromagnetic coil unit 80 is not energized, but a counterclockwise rotational force acts on the rotor 52 of the rotary drive member 50 due to the magnetic attraction and repulsion forces generated between the two magnetic poles 52A, 52B of the rotor 52 of the rotary drive member 50 and the magnetic poles formed by the four yokes 81A, 81B, 82A, 82B. As a result, the rotary drive member 50 is held in the position shown in Figure 8A. Furthermore, because the teeth of the gear portion 55 of the rotary drive member 50 and the teeth of the gear portion 65 of the rotary drive member 60 mesh with each other, the rotary drive member 60 is also held in the position shown in Figure 8A. This position of the rotary drive member 60 is referred to as the "first rotation position".

[0036] When the photographer presses the release button in the state shown in Figure 8A, the coil 84 is energized, generating, for example, north poles on yokes 81A and 81B and south poles on yokes 82A and 82B. This change in magnetic poles generates a clockwise rotational force on the rotor 52 of the rotary drive member 50, causing the rotary drive member 50 to rotate clockwise around the drive shaft 15. Consequently, the drive pin 54 of the rotary drive member 50 causes the blade arm 31 to rotate clockwise, and the aforementioned link mechanism moves the blades 21 and 22 in the -Y direction.

[0037] Here, when the rotary drive member 50 rotates clockwise, the teeth of the gear portion 55 of the rotary drive member 50 and the teeth of the gear portion 65 of the rotary drive member 60 mesh, causing the rotary drive member 60 to rotate counterclockwise around the drive shaft 16. Consequently, the drive pin 64 of the rotary drive member 60 causes the blade arm 33 to rotate counterclockwise, and the aforementioned link mechanism moves the blades 23 and 24 in the +Y direction.

[0038] Finally, the arm portion 53 of the rotary drive member 50 comes into contact with the -Y direction end of the arc groove 17 of the base plate 10, causing the rotary drive member 50 to stop, and the rotary drive member 60 also stops. As a result, the blades 21-24 retract to the outside of the opening S in the base plate 10, as shown in Figure 8B, and the opening S is opened.

[0039] In the state shown in Figure 8B, a clockwise rotational force acts on the rotor 52 of the rotary drive member 50 due to the magnetic attraction and repulsion forces generated between the two magnetic poles 52A and 52B of the rotor 52 of the rotary drive member 50 and the magnetic poles formed by the four yokes 81A, 81B, 82A, and 82B. Therefore, even if the power supply to the coil 84 is stopped after the blades 21-24 have moved to the open position shown in Figure 8B, a clockwise rotational force is generated on the rotary drive member 50, and the rotary drive member 50 is held in the position shown in Figure 8B. In addition, the rotary drive member 60 is also held in the position shown in Figure 8B due to the meshing of the teeth of the gear portion 55 of the rotary drive member 50 and the teeth of the gear portion 65 of the rotary drive member 60. The position of the rotary drive member 60 at this time will be referred to as the "second rotational position".

[0040] Thus, according to this embodiment, when the rotary drive member 50 is rotated clockwise, the teeth of the gear portion 55 of the rotary drive member 50 and the teeth of the gear portion 65 of the rotary drive member 60 mesh, causing the rotary drive member 60 to rotate counterclockwise. As a result, the blades 21, 22 and 23, 24 move in opposite directions, opening the opening S of the base plate 10. Therefore, compared to the case where all blades move in one direction to close the opening S, the travel distance of each blade 21-24 required to open the opening S of the base plate 10 can be reduced by half, and the opening S of the base plate 10 can be opened at high speed.

[0041] Here, if the movement speed of the blades 21-24 is high, it is conceivable that when they stop in the open position shown in Figure 8B, they may bounce back and some of the blades 21-24 may enter the opening S, thus negatively affecting the image. However, in this embodiment, as described below, the speed of the blades 21-24 is reduced before they stop in the open position shown in Figure 8B.

[0042] In other words, when the vanes 21-24 move from the closed position shown in Figure 8A to the open position shown in Figure 8B, the rotary drive member 60 rotates counterclockwise from the first rotation position to the second rotation position (opening operation). However, just before the rotary drive member 60 reaches the second rotation position, as shown in Figure 9A, the pusher 66 of the rotary drive member 60 comes into contact with the side surface 95 of the brake piece 94 of the braking member 90. If the rotary drive member 60 rotates further counterclockwise from this state, the pusher 66 will push the brake piece 94 of the braking member 90 counterclockwise. Since the brake pad 120 is pressed toward the brake piece 94 of the braking member 90 by the coil spring 110, a frictional force is generated between the outer circumferential surface 94A of the brake piece 94 of the braking member 90 and the sliding contact surface 121A of the brake pad 120, which slows down the rotation of the braking member 90, and consequently the rotation of the rotary drive member 60. This reduces the speed of the blades 23 and 24 just before they stop, and suppresses the rebound of the blades 23 and 24 when they stop. In addition, because the teeth of the gear portion 55 of the rotary drive member 50 and the teeth of the gear portion 65 of the rotary drive member 60 mesh with each other, the speed of the blades 21 and 22 just before they stop is also reduced, and the rebound of the blades 21 and 22 when they stop is also suppressed.

[0043] The rotary drive member 50 eventually rotates until its arm portion 53 contacts the -Y-direction end of the arc groove 17 of the base plate 10, as described above, reaching the position shown in Figure 8B. At this time, the teeth of the gear portion 55 of the rotary drive member 50 and the teeth of the gear portion 65 of the rotary drive member 60 mesh, causing the rotary drive member 60 to rotate to the second rotation position shown in Figure 9B. The position of the braking member 90 at this time is referred to as the "first standby position".

[0044] As described above, after the blades 21-24 move to the open position shown in Figure 8B, the charge accumulated in the image sensor is released, and the accumulation of charge for imaging begins. After a predetermined time has elapsed, a signal from the control circuit causes a current in the opposite direction to the current previously flowed through the coil 84, so that, for example, south poles are generated in the yokes 81A and 81B, and north poles are generated in the yokes 82A and 82B. This change in magnetic poles generates a counterclockwise rotational force in the rotor 52 of the rotary drive member 50, causing the rotary drive member 50 to rotate counterclockwise around the drive shaft 15. Accordingly, the blade arm 31 rotates counterclockwise by the drive pin 54 connected to the arm portion 53 of the rotary drive member 50, and the blades 21 and 22 move in the +Y direction by the link mechanism described above.

[0045] Furthermore, when the rotary drive member 50 rotates counterclockwise, the teeth of the gear portion 55 of the rotary drive member 50 mesh with the teeth of the gear portion 65 of the rotary drive member 60, causing the rotary drive member 60 to rotate clockwise around the drive shaft 16. Consequently, the drive pin 64 of the rotary drive member 60 causes the blade arm 33 to rotate clockwise, and the aforementioned link mechanism causes the blades 23 and 24 to move in the -Y direction.

[0046] Finally, the arm portion 53 of the rotary drive member 50 comes into contact with the +Y direction end of the arc groove 17 of the base plate 10, causing the rotary drive member 50 to stop, and the rotary drive member 60 also stops. As a result, the blades 21-24 close the opening S of the base plate 10, as shown in Figure 8A.

[0047] Thus, according to this embodiment, when the rotary drive member 50 is rotated counterclockwise, the teeth of the gear portion 55 of the rotary drive member 50 and the teeth of the gear portion 65 of the rotary drive member 60 mesh, causing the rotary drive member 60 to rotate clockwise. As a result, the blades 21, 22 and 23, 24 move in opposite directions to close the opening S of the base plate 10. Therefore, compared to the case where all blades move in one direction to close the opening S, the travel distance of each blade 21-24 required to close the opening S of the base plate 10 can be reduced by half, and the opening S of the base plate 10 can be closed at high speed.

[0048] Here, as the vanes 21-24 move from the open position shown in Figure 8B to the closed position shown in Figure 8A, the rotary drive member 60 rotates clockwise from the second rotation position to the first rotation position (closing operation). However, just before the rotary drive member 60 reaches the first rotation position, as shown in Figure 9C, the pusher 67 of the rotary drive member 60 comes into contact with the side surface 96 of the brake piece 94 of the braking member 90 (which is located in the first standby position). If the rotary drive member 60 rotates further clockwise from this state, the pusher 67 will push the brake piece 94 of the braking member 90 clockwise. Since the brake pad 120 is pressed toward the brake piece 94 of the braking member 90 by the coil spring 110, a frictional force is generated between the outer peripheral surface 94A of the brake piece 94 of the braking member 90 and the sliding contact surface 121A of the brake pad 120, which slows down the rotation of the braking member 90, and consequently the rotation of the rotary drive member 60. This reduces the speed of the blades 23 and 24 just before they stop, and suppresses the rebound of the blades 23 and 24 when they stop. In addition, because the teeth of the gear portion 55 of the rotary drive member 50 and the teeth of the gear portion 65 of the rotary drive member 60 mesh with each other, the speed of the blades 21 and 22 just before they stop is also reduced, and the rebound of the blades 21 and 22 when they stop is also suppressed.

[0049] The rotary drive member 50 eventually rotates until its arm portion 53 contacts the +Y-direction end of the arc groove 17 of the base plate 10, as described above, reaching the position shown in Figure 8A. At this time, the teeth of the gear portion 55 of the rotary drive member 50 and the teeth of the gear portion 65 of the rotary drive member 60 mesh, causing the rotary drive member 60 to rotate to the first rotation position shown in Figure 9D. The position of the braking member 90 at this time is referred to as the "second standby position". In the opening operation of the rotary drive member 60 described above, the pusher 66 of the rotary drive member 60 comes into contact with the side surface 95 of the brake piece 94 of the braking member 90, which is located in this second standby position (see Figure 9A).

[0050] Thus, in this embodiment, the pushers 66 and 67 of the rotary drive member 60 function as contact parts configured to contact the brake piece 94 of the braking member 90 and push the braking member 90 before the end of the opening operation and the end of the closing operation. As the pushers 66 and 67, as contact parts, contact the brake piece 94 of the braking member 90 and push the braking member 90 before the end of the opening operation and the end of the closing operation of the rotary drive member 60, a frictional force is generated by sliding contact between the outer peripheral surface 94A of the brake piece 94 of the braking member 90 and the sliding contact surface 121A of the brake pad 120, thereby decelerating the rotation of the braking member 90, and consequently the rotation of the rotary drive member 60. In addition, the rotation of the rotary drive member 50 is also decelerated by the meshing of the teeth of the gear portion 55 of the rotary drive member 50 and the teeth of the gear portion 65 of the rotary drive member 60. As a result, the speed of the blades 21 to 24 before they stop can be reduced, and the rebound of the blades 21 to 24 when they stop can be suppressed.

[0051] Furthermore, in this embodiment, the pusher 67 can move the braking member 90 to a position where the pusher 66 of the rotary drive member 60 can make contact (first standby position), and the pusher 66 can move the braking member 90 to a position where the pusher 67 of the rotary drive member 60 can make contact (second standby position). Therefore, it is possible to reduce the speed of the blades 21-24 both before the end of the opening operation and before the end of the closing operation.

[0052] Here, as shown in Figure 2, the base plate 10 has a wall portion 102 (restricting portion) that protrudes in the +Z direction. This wall portion 102 has restricting walls 102A and 102B (restricting portions) at both ends that extend toward the center of the drive shaft 16. These restricting walls 102A and 102B are positioned adjacent to the stopper piece 93 of the braking member 90 in the circumferential direction and are capable of engaging with the stopper piece 93 of the braking member 90. As shown in Figure 9D, the restricting wall 102A restricts the clockwise rotation of the braking member 90, and as shown in Figure 9B, the restricting wall 102B is configured to restrict the counterclockwise rotation of the braking member 90. These restricting walls 102A and 102B define the rotation range of the braking member 90. In this way, the restricting walls 102A and 102B of the base plate 10 define the range in which the braking member 90 can rotate, and malfunctions caused by the braking member 90 moving to an unintended position can be prevented.

[0053] In this embodiment, the braking member 90 is configured to rotate around the drive shaft 16 of the base plate 10 and to rotate around the same axis as the rotary drive member 60. However, the braking member 90 does not need to be positioned coaxially with the rotary drive member 60, and it does not necessarily need to rotate around the axis as long as it is movable in the vicinity of the rotary drive member 60.

[0054] In this embodiment, the rotary drive member 50 is driven by the electromagnetic coil unit 80, but the method of driving the rotary drive member 50 is not limited to electromagnetic means, and the rotary drive member 50 may be configured to be driven using a biasing means such as a spring. Also, although only the rotary drive member 50 of the two rotary drive members 50 and 60 is driven by the electromagnetic coil unit 80, both rotary drive members 50 and 60 may be configured to be driven.

[0055] As described above, according to the first aspect of the present invention, a blade drive device capable of opening and closing an opening at high speed is provided. Specifically, the blade drive device according to the present invention can employ the following configuration.

[0056] (Composition 1) The blade drive device comprises a base plate with an opening formed therein, at least one first blade movable between a first closed position that covers a part of the opening and a first open position that retracts to the outside of the opening, at least one second blade movable between a second closed position that covers a part of the opening and a second open position that retracts to the outside of the opening, a first connecting part connected to the at least one first blade, and a first gear part having a plurality of teeth formed along the circumferential direction, and rotates the at least one first blade by rotating around a first drive shaft. The device comprises a first rotary drive member that can move between the first closed position and the first open position, a second rotary drive member having a second connecting portion connected to the at least one second blade, and a second gear portion having a plurality of teeth formed circumferentially that mesh with the teeth of the first gear portion of the first rotary drive member, and which can move the at least one second blade between the second closed position and the second open position by rotating around a second drive shaft, and a drive unit that rotates the first rotary drive member.

[0057] With this configuration, when the first rotary drive member is rotated in one direction, the teeth of the first gear section of the first rotary drive member mesh with the teeth of the second gear section of the second rotary drive member, causing the second rotary drive member to rotate in the opposite direction. As a result, the first and second blades move in opposite directions, opening and closing the base plate. Therefore, compared to the case where all blades move in one direction, the distance the blades need to move to open and close the base plate opening can be reduced by half, and the opening and closing of the base plate opening can be increased in speed.

[0058] (Configuration 2) In the above configuration 1, it is preferable that the opening in the base plate is closed by the at least one first vane located in the first closed position and the at least one second vane located in the second closed position.

[0059] (Composition 3) In the above configuration 1 or 2, the blade drive device may further include a braking member configured to be movable near one of the first rotation drive member and the second rotation drive member, and a sliding contact member that slides against the outer circumferential surface of the braking member to suppress the movement of the braking member by friction. Preferably, one of the first and second rotational drive members described above is configured to move the at least one first blade or the at least one second blade from the first closed position or the second closed position to the first open position or the second open position by rotating from the first rotational position to the second rotational position, and to move the at least one first blade or the at least one second blade from the first open position or the second open position to the first closed position or the second closed position by rotating from the second rotational position to the first rotational position, and has a contact portion configured to contact the braking member and push the braking member before the completion of at least one of the opening operation, which is rotating from the first rotational position to the second rotational position, and the closing operation, which is rotating from the second rotational position to the first rotational position.

[0060] With this configuration, the contact portion of the rotary drive member contacts the braking member and pushes the braking member before the completion of at least one of the opening and closing operations of the rotary drive member. As a result, a frictional force is generated between the outer surface of the braking member and the sliding contact member, which slows down the rotation of the braking member, and consequently the rotation of either the first rotary drive member or the second rotary drive member. This reduces the speed of the blade before it stops and suppresses rebound when the blade stops.

[0061] (Composition 4) In the above configuration 3, it is preferable that the contact portion includes a first pusher that pushes the braking member in a first direction before the opening operation is completed, and a second pusher that pushes the braking member in a second direction opposite to the first direction before the closing operation is completed. These pushers can decelerate the rotation of the rotary drive member both before the opening operation and before the closing operation is completed.

[0062] (Composition 5) In the above configuration 4, the first pusher may be configured to move the braking member to a first standby position at the end of the opening operation, and the second pusher may be configured to contact the braking member located at the first standby position before the end of the closing operation. With such a configuration, the first pusher can move the braking member to a position (first standby position) that the second pusher can contact.

[0063] (Composition 6) In the above configuration 4 or 5, the second pusher may be configured to move the braking member to a second standby position at the end of the closing operation, and the first pusher may be configured to contact the braking member located at the second standby position before the end of the opening operation. With such a configuration, the braking member can be moved by the second pusher of the rotary drive member to a position (second standby position) that can be contacted by the first pusher of the rotary drive member.

[0064] (Composition 7) In any one of the above configurations 3 to 6, it is preferable that the base plate has a restricting portion that defines the range of movement of the braking member, and the braking member has a stopper piece that can engage with the restricting portion of the base plate. With such a configuration, the restricting portion of the base plate can define the range in which the braking member can move, and malfunctions caused by the braking member moving to an unintended position can be prevented.

[0065] (Composition 8) In any one of the above configurations 3 to 7, the blade drive device may further include a biasing member that presses the sliding contact member against the outer circumferential surface of the braking member.

[0066] (Composition 9) In any one of the above configurations 1 to 8, the first rotational drive member may have a rotor having different magnetic poles in the diametrical direction, and the drive unit may include an electromagnetic coil unit that rotates the rotor.

[0067] According to a second aspect of the present invention, an imaging device is provided comprising a blade drive device described in any one of the above configurations 1 to 9, and an image sensor arranged on a surface where light transmitted through the blade drive device forms an image.

[0068] Although preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the embodiments described above and may be implemented in various different forms within the scope of its technical concept. [Explanation of Symbols]

[0069] 1. Blade drive device 10 Main plate 15 (First) drive shaft 16 (Second) drive shaft 17,18 Arc groove 21, 22 (First) feather 23, 24 (Second) feather 31-34 Wing Arm 50 (First) Rotary Drive Member 51 Shaft 52 rotors 53 Arm 54 Drive pin (first connecting part) 55 (First) Gear Section 60 (Second) Rotary Drive Member 61 Shaft 63 Arm 64 Drive pin (second connecting part) 65 (Second) Gear Section 66 (First) Pusher 67 (Second) Pusher 80 Electromagnetic coil unit (drive unit) 81A, 81B, 82A, 82B York 83A, 83B bobbins 84 coils 90 Braking member 93 Stopper piece 94 Brake fragments 102A, 102B Regulatory wall (regulatory section) 110 Coil spring (biasing member) 120 Brake pads (sliding contact members) S opening

Claims

1. A floorboard with an opening formed therein, At least one first vane that is movable between a first closed position that covers a portion of the opening and a first open position that retracts to the outside of the opening, At least one second vane that is movable between a second closed position that covers a portion of the opening and a second open position that retracts to the outside of the opening, A first rotary drive member having a first connecting portion connected to at least one first blade and a first gear portion having a plurality of teeth formed circumferentially, and capable of moving the at least one first blade between a first closed position and a first open position by rotating around a first drive shaft, A second rotational drive member having a second connecting portion connected to at least one second blade, and a second gear portion having a plurality of teeth formed circumferentially that mesh with the teeth of the first gear portion of the first rotational drive member, and capable of moving the at least one second blade between the second closed position and the second open position by rotating around a second drive shaft, A drive unit that rotates the first rotary drive member, A braking member rotatable around the second drive shaft, A sliding contact member that contacts the outer circumferential surface of the braking member in a radial direction centered on the second drive shaft and suppresses the rotation of the braking member by friction, Equipped with, The second rotational drive member has a contact portion that contacts the braking member and pushes the braking member around the second drive shaft before the completion of at least one of the following operations: an opening operation that moves the at least one second blade from the second closed position to the second open position and a closing operation that moves the at least one second blade from the second open position to the second closed position. The first drive shaft and the second drive shaft extend in the same direction, and are positioned at different locations relative to each other when viewed in the direction in which the first drive shaft and the second drive shaft extend. A vane drive device in which, when viewed in the direction in which the first drive shaft and the second drive shaft extend, the first rotary drive member, the second rotary drive member, and the sliding contact member are arranged in the direction in which the first drive shaft and the second drive shaft are aligned.

2. The blade drive device according to claim 1, wherein the opening in the base plate is closed by the at least one first blade located in the first closed position and the at least one second blade located in the second closed position.

3. The aforementioned contact portion is A first pusher pushes the braking member in a first direction around the second drive shaft before the opening operation is completed, A second pusher pushes the braking member in a second direction opposite to the first direction around the second drive shaft before the closing operation is completed, The blade drive device according to claim 1, including the following:

4. The first pusher is configured to move the braking member to a first standby position when the opening operation is completed. The vane drive device according to claim 3, wherein the second pusher is configured to contact the braking member located in the first standby position before the closing operation is completed.

5. The second pusher is configured to move the braking member to a second standby position when the closing operation is completed. The vane drive device according to claim 3, wherein the first pusher is configured to contact the braking member located in the second standby position before the opening operation is completed.

6. The base plate has a restricting portion that defines the range of movement of the braking member, The vane drive device according to any one of claims 1 to 5, wherein the braking member has a stopper piece that can engage with the restricting portion of the base plate.

7. The vane drive device according to any one of claims 1 to 5, further comprising a biasing member that presses the sliding contact member against the outer circumferential surface of the braking member.

8. The first rotational drive member has a rotor having different magnetic poles in the diametrical direction, The blade drive device according to any one of claims 1 to 5, wherein the drive unit includes an electromagnetic coil unit for rotating the rotor.

9. A blade drive device according to any one of claims 1 to 5, An image sensor is positioned on the plane where light transmitted through the aforementioned vane drive device forms an image, An imaging device equipped with the following features.

Images