JP6529343B2 - Focal plane shutter for camera and camera - Google Patents

Description

  The present invention relates to a focal plane shutter for a camera and a camera.

  In general, a focal plane shutter for a camera comprises a base plate provided with an opening for irradiating light from a subject to a solid-state imaging device, and a shutter including a blade group attached to the base plate to be able to change the opening and closing of the opening. Prepare the curtain. The shutter curtain is driven, for example, using an actuator that rotates a rotor by magnetic force generated by a coil (see, for example, Patent Document 1).

  By the way, in recent cameras, for example, there is a demand for an increase in size of an image sensor and an increase in shutter speed. When a large-sized image sensor is mounted, the opening of the main plate usually increases in accordance with the size of the image sensor, and the blades for opening and closing it also become larger, and the blades become heavier accordingly. Therefore, it may be necessary to increase the driving force for driving the blades by the actuator. Also, in order to realize a high shutter speed, it is often desirable to increase the moving acceleration of the blades. Therefore, it may be necessary to increase the driving force for driving the blades by the actuator. As a method of increasing this driving force, it is conceivable to enlarge the rotor and yoke that constitute the actuator.

JP, 2012-215658, A

  However, when the rotor and yoke become large, the detent torque generally increases, and as a result, the responsiveness of the shutter curtain may decrease, or the drive power required to drive the shutter curtain may increase. There is. Here, the detent torque is a suction force that acts between the rotor and the yoke in a state in which no electromagnetic force is generated from the coil, that is, in a state in which the yoke is not excited.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a focal plane shutter for a camera and a camera capable of improving the responsiveness of the shutter curtain and reducing the driving power of the shutter curtain. .

In order to achieve the above object, a focal plane shutter for a camera according to the present invention is
A shutter curtain that operates to open and close an opening provided in the base plate;
An actuator for operating the shutter curtain;
The actuator is
Yoke,
A coil wound on the yoke;
And a rotor that rotates around a rotation axis to operate the shutter curtain by a magnetic force that acts from the yoke when the coil is energized.
The yoke is
The first sub yoke,
Wherein and the first sub yokes are spaced in the direction of the rotation axis of the rotor, possess a second sub-yokes which a permanent magnet is provided, and
The permanent magnet is
The arrangement direction of the north pole and the south pole is arranged along one closed magnetic path which can be formed by the second sub yoke and the rotor .

Further, each of the first sub yoke and the second sub yoke is
Two legs parallel to each other,
And a connecting piece for connecting one ends of the two leg pieces.
In the rotor, a portion on one end side in the rotation axis direction is located between the other ends of the two leg pieces of the first sub yoke, and a portion on the other end side in the rotation axis direction is the Located between the other end of each of the two legs of the second sub-yoke,
The permanent magnet may be embedded in the connection piece such that the alignment direction of the N pole and the S pole corresponds to the direction from one of the two leg pieces to the other.

Further, the yoke further includes
A shielding member may be provided between the first sub-yoke and the second sub-yoke to shield the electromagnetic field in the first sub-yoke and the electromagnetic field in the second sub-yoke from each other.

  Further, the force acting on the rotor from the first sub yoke may be larger than the force acting on the rotor from the second sub yoke when the coil is not energized.

  Further, the first thickness of the first sub yoke in the rotation axis direction of the rotor may be thicker than the second thickness of the second sub yoke in the rotation axis direction.

The camera according to the present invention seen from another point of view is
The above focal plane shutter for camera,
A lens portion comprising one or more lenses;
A control unit that controls an operation of the camera focal plane shutter at the time of shooting;
And a solid-state imaging device configured to convert light imaged through the lens unit into an electrical signal according to the operation of the camera focal plane shutter.

  According to the present invention, the permanent magnet is provided in the second sub yoke. The magnetic force from the permanent magnet biases the rotor in the rotational direction at the time of photographing by appropriately setting the direction of the permanent magnet. Therefore, the initial movement of the rotor at the time of photographing can be made faster than when the permanent magnet is not provided. Therefore, it is possible to improve the responsiveness of the shutter curtain.

  In addition, while the shutter curtain is operated at the time of photographing, not only the electromagnetic force from the coil but also the magnetic force from the permanent magnet can be used to rotate the rotor, so that the permanent magnet is not provided. The magnetic flux density of the yoke can be saturated with small power. Therefore, it is possible to reduce the drive power of the shutter curtain.

It is a perspective view of a camera concerning an embodiment. It is an exploded perspective view of a focal plane shutter for cameras concerning an embodiment. It is a front view of a focal plane shutter for cameras concerning an embodiment. It is a front view of a shutter curtain, an actuator, a drive gear, and an output gear according to the embodiment. It is a cross-sectional arrow line view in the AA line of FIG. 4 of the shutter curtain which concerns on embodiment, an actuator, a drive gear, and an output gear. It is a circuit diagram of a control device concerning an embodiment. It is operation | movement explanatory drawing of the actuator which concerns on embodiment. It is operation | movement explanatory drawing of the focal plane shutter for cameras which concerns on embodiment. It is operation | movement explanatory drawing of the actuator which concerns on embodiment. It is operation | movement explanatory drawing of the focal plane shutter for cameras which concerns on embodiment. It is operation | movement explanatory drawing of the actuator which concerns on embodiment. It is a top view of the actuator concerning a modification. It is a front view of a focal plane shutter for cameras concerning a modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the camera 1000 according to the present embodiment includes the focal plane shutter 1 for a camera, the control device 3, the solid-state imaging device 5, a housing 1001 for housing these, and one or more of them. And a lens unit 1020 including a lens. The camera 1000 is a digital camera, a still camera or the like. The housing 1001 is provided with an operation button 1010 operated by the user at the time of shooting. The control device 3 is a device that controls the overall operation of the camera 1000, and includes a processor, a memory, and the like. For example, when the operation button 1010 is pressed at the time of photographing, the control device 3 operates the camera focal plane shutter 1. The solid-state imaging device 5 is an element that converts light imaged through the lens unit 1020 into an electrical signal, and includes, for example, a charge coupled device (CCD) image sensor, a complementary MOS (CMOS) image sensor, or the like. In the present embodiment, the camera focal plane shutter 1 is described as being a single-curtain type.

  As shown in FIG. 2, the focal plane shutter 1 for a camera is a so-called square shutter, and includes a base plate 210, a shutter curtain 150, arms 141 and 142, a drive gear 131, an actuator 120, and a holder 220.

  The ground plate 210 has an opening 211 having a rectangular shape in plan view at a part thereof. As shown in FIG. 3, shaft portions 143 and 144 that pivotally support the arms 141 and 142 are provided on the outer peripheral portion of the opening 211 in the ground plate 210. Further, the main plate 210 has a shaft portion 143 that rotatably supports a drive gear 131 described later.

  The shutter curtain 150 is composed of a plurality of blades, and in the present embodiment is composed of four blades 151, 152, 153, 154. The shutter curtain 150 is connected to the arms 141 and 142, and at the time of photographing, the arm 141 pivots around the shaft portion 143 and the arm 142 pivots around the shaft portion 144, and is vertically moved in plan view. Moving.

  In detail, the shutter curtain 150 is in a state of covering a part of the opening 211 by moving the blades 151, 152, 153, 154 from the superimposed state. When the blades 151, 152, 153, 154 move further from that state, the shutter curtain 150 is in the unfolded state and the opening 211 is fully closed.

  The superimposed state is a state in which the plurality of blades 151, 152, 153, 154 overlap with the outer peripheral portion of the opening 211 of the main plate 210 in a plan view. In the superimposed state, the opening 211 is entirely open in plan view.

  The unfolded state is a state in which the plurality of blades 151, 152, 153, 154 unfold and cover the opening 211 of the ground plate 210 in plan view. In the unfolded state, the opening 211 is in a fully closed state where everything is covered in plan view. FIG. 3 shows the shutter curtain 150 in the unfolded state.

  The shutter curtain 150 is connected to the arms 141 and 142. The arm 141 is rotatably supported by a shaft portion 143 provided on the main plate 210. The arm 142 is rotatably supported by a shaft portion 144 provided on the main plate 210. As shown in FIG. 3, the arm 141 is connected to the blade 151 via the pin 141a, is connected to the blade 152 via the pin 141b, is connected to the blade 153 via the pin 141c, and is via the pin 141d. It is linked to 154. The arm 142 is connected to the blade 151 via the pin 142a, is connected to the blade 152 via the pin 142b, is connected to the blade 153 via the pin 142c, and is connected to the blade 154 via the pin 142d. There is.

  As shown in FIG. 4, the actuator 120 has a yoke 122, a coil 121 wound around a part of the yoke 122, and a rotor 123 for rotating the shutter curtain 150 by rotating around the rotation axis J2. . The coil 121 is connected to the control device 3 via a conductive wire. The rotor 123 is rotated by the magnetic force acting from the yoke 122 when the coil 121 is energized. The coil 121 is formed of a conductive material such as copper. The rotor 123 is formed of a magnet magnetized so that the N pole and the S pole are aligned in the direction orthogonal to the rotation axis J2.

  As shown in FIGS. 2 and 5, the yoke 122 has a first sub-yoke 122a and a permanent magnet 122d embedded in part, and is spaced from the first sub-yoke 122a in the direction of the rotation axis J2 of the rotor 123. And a second sub yoke 122b. Further, the yoke 122 has a shielding member 122c interposed between the first sub yoke 122a and the second sub yoke 122b to shield the electromagnetic field of the first sub yoke 122a and the electromagnetic field of the second sub yoke 122b from each other. Thereby, the loss of the magnetic flux in the first sub yoke 122a can be reduced, so the utilization efficiency of the electromagnetic force generated in the coil 121 can be improved, and the power to be supplied to the coil 121 can be reduced. .

  The first sub-yoke 122a is a long columnar pillar having a substantially rectangular cross section, has two leg pieces 125a arranged in parallel to each other, and a columnar pillar having a substantially rectangular cross section, and connects one end portions of the two leg pieces 125a to each other And has a substantially C-shaped shape as a whole. And the site | part of the one end side (-Z direction side of FIG. 5) in the rotating shaft J2 direction of the rotor 123 is located between the other end parts of the two leg pieces 125a. The first sub yoke 122a is formed of a magnetic material.

  Further, the second sub yoke 122b also has substantially the same shape as the first sub yoke 122a in a plan view, and is a connection for connecting one end portions of two leg pieces 126a and two leg pieces 126a arranged in parallel to each other. And a piece 126b. And the site | part of the other end side (+ Z direction side of FIG. 5) in the rotating shaft J2 direction of the rotor 123 is located between the other end parts of the two leg pieces 126a. The second sub yoke 122 b is formed of a magnetic material. Further, as shown in FIG. 5, the thickness (first thickness) W1 of the first sub-yoke 122a is set thicker than the thickness (second thickness) W2 of the second sub-yoke 122b. That is, the cross sectional area of the first sub yoke 122a is set larger than the cross sectional area of the second sub yoke 122b. Here, if the magnetomotive forces of the magnetic circuits corresponding to the magnetic paths formed in the first sub yoke 122a and the second sub yoke 122b are the same, the magnetic flux density of the magnetic flux flowing in the first sub yoke 122a flows in the second sub yoke 122b. It becomes larger than the flux density of the flux. The ratio of the thicknesses W1 and W2 is a force (detent torque) acting on the rotor 123 from the first sub yoke 122a to a force acting on the rotor 123 from the second sub yoke 122b when the coil 121 is not energized. It is set to be larger than it. Thus, in a state where the coil 121 is not energized, the shutter curtain 150 can be maintained in the superimposed state while reducing the detent torque acting on the rotor 123.

  The permanent magnet 122 d is arranged such that the alignment direction of its north pole and south pole is along one closed magnetic path which can be formed by the second sub yoke 122 b and the rotor 123. Here, the direction in which the N pole and the S pole are aligned is, in other words, the magnetization direction of the permanent magnet 122 d. The single closed magnetic path has a path from the rotor 123 back to the rotor 123 through the one leg 126a, the coupling piece 126b, and the other leg 126b of the two legs 126a. The permanent magnet 122d is embedded in the connecting piece 126b such that the alignment direction of the N pole and the S pole is in agreement with the direction (+ X direction in FIG. 4) from one of the two leg pieces 126a to the other. The shielding member 122c is made of a nonmagnetic material such as a resin material. The shielding member 122c has substantially the same shape as the first sub yoke 122a and the second sub yoke 122b in a plan view.

  The drive gear 131 is for driving the arm 141, and is provided integrally with the arm 141, and the rotation axis J1 coincides with the central axis of the shaft portion 143. The drive gear 131 is fixed to the base end of the arm 141 opposite to the side connected to the shutter curtain 150. As shown in FIG. 2, the drive gear 131 has an insertion hole 131 a into which the shaft portion 143 is inserted, and the arm 141 pivots around the shaft portion 143 when the drive gear 131 rotates around the rotation shaft J1. .

  The output gear 124 is a gear for transmitting the torque generated by the actuator 120 to the drive gear 131. The output gear 124 according to the present embodiment is fixed to the rotor 123 by fitting, and thereby rotates in conjunction with the rotor 123. The output gear 124 has arc-shaped teeth, which are in mesh with the drive gear 131.

  According to such a configuration, when the rotor 123 rotates, the output gear 124 rotates about the rotation axis J 2 of the rotor 123, and the output of the output gear 124 is transmitted to the drive gear 131. When the drive gear 131 rotates, the drive gear 131 of the arm 141 fixed to the drive gear 131 turns around the rotation axis J1. Then, the shutter curtain 150 moves as the arm 141 pivots. When the rotor 123 rotates counterclockwise, the state of the shutter curtain 150 shifts from the superimposed state to the unfolded state. On the other hand, when the rotor 123 rotates clockwise, the state of the shutter curtain 150 shifts from the unfolded state to the superimposed state.

  The holder 220 holds the actuator 120. The holder 220 is fixed to the main plate 210 by an adhesive or the like. The holder 220 is formed of synthetic resin or the like. The holder 220 is comprised from the holder main body 220a and the cover part 220b, as shown in FIG. The holder main body 220 a has a shaft 223 for rotatably supporting the rotor 123 of the actuator 120. A screw hole 220c is provided on the side of the holder body 220a opposite to the lid 220b, and a through hole 220d is provided at a position corresponding to the screw hole 220c in the lid 220b. The lid 220 b is fixed to the holder main body 220 a by screwing the screw 221 inserted into the through hole 220 d into the screw hole 220 c.

  Next, the configuration of the control device 3 will be described. The control device 3 controls the state of the shutter curtain 150 by supplying a current to the coil 121. As shown in FIG. 6, the control device 3 includes a drive circuit 320 that drives the camera focal plane shutter 1, a control circuit 310 that controls the drive circuit 320, and a battery that supplies power to the drive circuit 320 and the control circuit 310. And 300.

  The battery 300 is a power supply that supplies, for example, a voltage within a range of up to 3.2 V to at least 2.2 V to the drive circuit 320 and the control circuit 310.

  The drive circuit 320 has a function of switching the direction of the current flowing through the coil 121, and is formed of a circuit of a bridge configuration including four transistors Tr11, Tr12, Tr13, and Tr14. Here, when a current flows from the left side to the right side of FIG. 6 in the coil 121, the yoke 122 is excited so that the + Z direction side is an N pole and the −Z direction side is an S pole in FIGS. I assume. Further, when current flows from the right to the left in FIG. 6 in the coil 121, the yoke 122 is excited so that the −Z direction side in FIG. 3 and FIG. 4 has an N pole and the + Z direction side has an S pole. Do.

  The control circuit 310 individually controls the transistors Tr11, Tr12, Tr13, and Tr14 provided in the drive circuit 320. The control circuit 310 is connected to an input device (not shown) having an operation button 1010 provided on the camera 1000. When the operation button 1010 is pressed by the user, the input device outputs, to the control circuit 310, a photographing instruction signal instructing to drive the blades 151, 152, 153, 154 that constitute the shutter curtain 150. The control circuit 310 moves the shutter curtain 150 from the superimposed state to the deployed state or from the deployed state to the superimposed state in response to the input of the photographing instruction signal.

  Next, the operation of the camera focal plane shutter 1 according to the present embodiment will be described. First, before imaging, a current is not supplied from the control circuit 310 to the coil 121 of the actuator 120, which is a so-called non-energized state. In this state, in the first sub-yoke 122a, as shown in FIG. 7A, the magnetic field represented by the magnetic force line MP11 coming out of the N pole of the rotor 123 and entering the S pole of the rotor 123 becomes dominant. There is. In this case, the detent torque acts on the rotor 123 from the first sub-yoke 122a in the clockwise direction as viewed from the + Z direction of FIG. 7A (see arrow AR11). On the other hand, in the second sub yoke 122b, as shown in FIG. 7B, in the permanent magnet 122d, the direction in which the N pole and the S pole are aligned (+ X direction in FIG. 4) coincides with the extension direction of the connecting piece 126b. Embedded in the connection piece 126b. In the second sub yoke 122b, the magnetic field represented by a magnetic line of force MP12 that is output from the N pole of the permanent magnet 122d enters the S pole of the rotor 123 and exits the N pole of the rotor 123 and enters the S pole of the permanent magnet 122d It has become. As a result, a force acts on the rotor 123 from the second sub yoke 122b in the direction to rotate counterclockwise as viewed from the + Z direction in FIG. 7B (see arrow AR12).

  As described above, the thickness W1 of the first sub yoke 122a is set to be thicker than the thickness W2 of the second sub yoke 122b. Thus, the detent torque acting on the rotor 123 from the first sub yoke 122a is larger than the force acting on the rotor 123 from the second sub yoke 122b. Therefore, as shown in FIG. 8, a force acts on the rotor 123 and the output gear 124 in the clockwise direction as viewed from the + Z direction (see arrow AR13), and the drive gear 131 is viewed from the + Z direction. A force acts in a counterclockwise direction (see arrow AR14). Thus, the shutter curtain 150 is maintained in the superimposed state.

  When the operation button 1010 is pressed during photographing, the control circuit 310 turns on the transistors Tr11 and Tr14 and turns off the transistors Tr12 and Tr13. Thereby, current flows from the left side to the right side of FIG. 6 in the coil 121, and the yoke 122 is excited so that the + Y direction side in FIG. 3 and FIG. 4 becomes the N pole and the −Y direction side becomes the S pole.

  In this state, in the first sub yoke 122a, as shown in FIG. 9A, the magnetic field represented by the magnetic field line MP21 coming out of the N pole of the rotor 123, passing through the coil 121 and entering the S pole of the rotor 123 is Become dominant. In this case, a force acts on the rotor 123 from the first sub yoke 122a in a counterclockwise direction as viewed from the + Z direction (see an arrow AR21). On the other hand, in the second sub yoke 122b, as shown in FIG. 9B, the N pole of the permanent magnet 122d comes out, passes through the coil 121, enters the S pole of the rotor 123, and goes out of the N pole of the rotor 123. The magnetic field represented by the magnetic field line MP22 entering the S pole of the permanent magnet 122d becomes dominant. As a result, a force acts on the rotor 123 from the second sub yoke 122b in a direction to rotate counterclockwise as viewed from the + Z direction (see arrow AR22).

  As described above, the force applied from the first sub yoke 122 a to the rotor 123 and the force applied from the second sub yoke 122 b to the rotor 123 both rotate the rotor 123 counterclockwise as viewed from the + Z direction. Works. Therefore, as shown in FIG. 10, the rotor 123 and the output gear 124 rotate counterclockwise as viewed from the + Z direction (see arrow AR23), and the drive gear 131 rotates clockwise as viewed from the + Z direction (arrow AR24). Then, the shutter curtain 150 moves from the superimposed state to the expanded state (see an arrow AR25).

  After a specific time has passed since the shutter curtain 150 was in the unfolded state, the control circuit 310 turns off the transistors Tr11 and Tr14 and turns on the transistors Tr12 and Tr13. Thus, current flows from the right to the left in FIG. 6 in the coil 121, and the yoke 122 is excited so that the −Y direction side in FIG. 3 and FIG. 4 has an N pole and the + Y direction side has an S pole.

  In this state, in the first sub yoke 122a, as shown in FIG. 11A, the magnetic field represented by magnetic field line MP31 coming out of the N pole of rotor 123 and passing through coil 121 and entering the S pole of rotor 123 is Become dominant. In this case, a force acts on the rotor 123 from the first sub yoke 122a in the clockwise direction as viewed from the + Z direction (see arrow AR31). On the other hand, in the second sub yoke 122b, as shown in FIG. 11B, the N pole of the permanent magnet 122d comes out, passes through the coil 121, enters the S pole of the rotor 123, and goes out of the N pole of the rotor 123. The magnetic field represented by the magnetic force line MP32 entering the S pole of the permanent magnet 122d becomes dominant. As a result, a force acts on the rotor 123 from the second sub yoke 122b in the direction to rotate counterclockwise as viewed from the + Z direction (see arrow AR32).

  At this time, the force acting on the rotor 123 from the first sub-yoke 122 a is larger than the force acting on the rotor 123 from the second sub-yoke 122 b. Therefore, contrary to the case shown in FIG. 9, the rotor 123 and the output gear 124 rotate clockwise, and the drive gear 131 rotates counterclockwise. Then, the shutter curtain 150 moves from the unfolded state to the superimposed state. The force acting on the rotor 123 from the second sub-yoke 122 b acts in a direction that inhibits the clockwise rotation of the rotor 123. Therefore, when the shutter curtain 150 moves from the unfolded state to the superimposed state, the acceleration of the shutter curtain 150 is smaller than when the shutter curtain 150 moves from the superimposed state to the unfolded state.

  As described above, according to the focal plane shutter 1 for a camera of the present embodiment, the permanent magnet 122 d is provided in the second sub yoke 122 b. The magnetic force from the permanent magnet 122 d biases the rotor 123 in the rotational direction (counterclockwise direction) at the time of photographing by appropriately setting the direction of the permanent magnet 122 d. Therefore, since the rotor 123 can be biased in the rotational direction at the time of shooting before shooting, the initial movement of the rotor 123 at the time of shooting can be made faster than in the case where the permanent magnet 122 d is not provided. Accordingly, the responsiveness of the shutter curtain 150 can be improved.

  Further, while the shutter curtain 150 is operated at the time of photographing, since the rotor 123 can be rotated using not only the electromagnetic force from the coil 121 but also the magnetic force from the permanent magnet 122 d, the permanent magnet 122 d is provided. It is possible to saturate the magnetic flux density of the yoke 122 with less power than in the case where it is not used. Therefore, the drive power of the shutter curtain 150 can be reduced.

  Further, permanent magnet 122 d according to the present embodiment is arranged such that the alignment direction of its N pole and S pole is along one closed magnetic path which can be formed by second sub yoke 122 b and rotor 123. There is. Thus, when the shutter curtain 150 is shifted from the superimposed state to the unfolded state, the force to rotate the rotor 123 counterclockwise as viewed from the + Z direction in FIG. 4 is enhanced. Therefore, the acceleration of the shutter curtain 150 can be increased.

(Modification)
As mentioned above, although embodiment of this invention was described, this invention is not limited to the structure of above-mentioned embodiment. For example, the permanent magnet 122 d may be arranged to apply a force to rotate the rotor 123 clockwise from the second sub yoke 122 b to the rotor 123. In this case, the permanent magnet 122d may be embedded in the connecting piece 126b so that, for example, the alignment direction of the N pole and the S pole coincides with the + X direction in FIG.

  The yoke 122 according to the above-described embodiment has been described as to the configuration having the shielding member 122c interposed between the first sub yoke 122a and the second sub yoke 122b, but is not limited to the configuration having the shielding member 122c. . For example, an air gap may be formed between the first sub yoke 122a and the second sub yoke 122b. According to this configuration, since the shielding member 122c can be omitted, the number of parts of the yoke can be reduced, and the weight of the yoke can be reduced.

  In the actuator 120 according to the above embodiment, the permanent magnet 122d in the second sub yoke 122b is embedded in the connecting piece 126b, but the position where the permanent magnet 122d is embedded is limited to the connecting piece 126b. is not. For example, as in the actuator 2120 shown in FIG. 12, the permanent magnet 2122d may be embedded in one leg 2126a of the second sub yoke 2122b having two leg pieces 2126a and a connection piece 2126b.

  In the above embodiment, the thickness W1 of the first sub yoke 122a is set to be thicker than the thickness W2 of the second sub yoke 122b, so that rotation is performed from the first sub yoke 122a in a state in which the coil 121 is not energized. The configuration has been described in which the force acting on the child 123 is greater than the force acting on the rotor 123 from the second sub yoke 122 b. However, when the coil 121 is not energized, the force applied to the rotor 123 from the first sub yoke 122a is larger than the force applied to the rotor 123 from the second sub yoke 122b. It is not limited. For example, the gap between the first sub-yoke 122 a and the rotor 123 may be set smaller than the gap between the second sub-yoke 122 b and the rotor 123.

  Although the above embodiment has described the configuration in which no current is supplied from the control circuit 310 to the coil 121 of the actuator 120 in the state before imaging, the present invention is not limited to this configuration. For example, in the state before photographing, the control circuit 310 may be configured to keep the transistors Tr11 and Tr14 off and the transistors Tr12 and Tr13 on. Thus, current flows from the right to the left in FIG. 6 in the coil 121, and the yoke 122 is excited so that the −Y direction side in FIG. 3 and FIG. 4 has an N pole and the + Y direction side has an S pole. In this state, a force acts on the rotor 123 from the first sub-yoke 122a in the clockwise direction as viewed from the + Z direction (see arrow AR21). Since the force acting on the rotor 123 from the first sub-yoke 122a is larger than the force acting on the rotor 123 from the second sub-yoke 122b, the shutter curtain 150 is maintained in the superimposed state .

  According to this configuration, it is not necessary to adjust the ratio of the thickness of the first sub-yoke 122a to the thickness of the second sub-yoke 122b, so that the manufacturing of the actuator 120 can be facilitated.

  In the above embodiment, an example of the so-called single-curtain type camera focal plane shutter 1 having one shutter curtain 150 has been described, but the number of shutter curtains 150 is not limited to one. For example, the camera focal plane shutter may have a so-called two-curtain type configuration including two shutter curtains 150.

  As shown in FIG. 13, the focal plane shutter 3001 for a camera according to the present modification includes two sets of the actuator 120, the drive gear 131, the output gear 124, the shutter curtain 150, and the like described in the first embodiment.

  In this camera focal plane shutter 3001, for example, the shutter curtain 150 on the -Y direction side in FIG. 13 can be set as a so-called front curtain, and the shutter curtain 150 on the + Y direction side can be set as a rear curtain. In this case, the control circuit first executes the shutter drive processing of the first embodiment for the shutter curtain 150 of the front curtain, thereby changing the shutter curtain 150 of the front curtain from the fully open state to the fully closed state. Control the drive circuit to Thereafter, when the preset time has elapsed, the control circuit executes the shutter drive processing of the first embodiment for the shutter curtain 150 of the rear curtain to fully close the shutter curtain 150 from the fully open state. And then control the drive circuit to be fully open again. The solid-state imaging device is provided at a position where the light passing through the opening 3211 of the main plate 3210 forms an image, and therefore the shutter curtain 150 of the rear curtain is fully opened after the shutter curtain 150 of the front curtain becomes fully open from fully closed. Images can be captured during the time between closures.

  In the above-described embodiment, an example in which the shutter curtain 150 is composed of four blades 151, 152, 153, 154 has been described, but the number of blades constituting the shutter curtain is not limited to four. For example, it may be less than four, or more than four.

  In the above embodiment, although an example in which one shutter curtain 150 functions as a rear curtain has been described, for example, after driving one shutter curtain 150 as a front curtain, it may be driven as a rear curtain. Good.

  In the digital camera according to the above-described embodiment, when the operation button 1010 is pressed with the shutter curtain 150 fully open (superimposed state), the shutter curtain 150 is fully closed (deployed state), and then the shutter is again applied. The example in which the curtain 150 is fully open has been described. For example, when the shutter curtain 150 is fully closed and the operation button 1010 is pressed, the shutter curtain 150 may be fully opened, and then the shutter curtain 150 may be fully closed again. In this case, the exposure time can be adjusted by adjusting the time during which the shutter curtain 150 is fully open.

1: Focal plane shutter for camera, 3: Controller: 5: solid-state image sensor, 120: actuator, 121: coil, 122: yoke, 122a: first sub-yoke, 122b: second sub-yoke, 122c: shielding member, 122d, 2122d: permanent magnet, 123: rotor, 124: output gear, 131: drive gear, 131a: insertion hole, 141, 142: arm, 141a, 141b, 141c, 141d, 142a, 142b, 142c, 142d: pin, 143 , 144, 223: shaft portion, 150: shutter curtain, 151, 152, 153, 154: blade, 210, 3210: base plate, 211, 3211: opening, 220: holder, 220a: holder main body, 220b: lid portion, 221 : Screw, 300: Battery (power), 310: Control circuit, 320: Drive Circuit, 1000: Camera, 1001: casing, 1010: operation buttons, 1020: lens unit, J1, J2: rotary shaft, Tr11, Tr12, Tr 13, Tr14: transistor

Claims (6)

A shutter curtain that operates to open and close an opening provided in the base plate;
An actuator for operating the shutter curtain;
The actuator is
Yoke,
A coil wound on the yoke;
And a rotor that rotates around a rotation axis to operate the shutter curtain by a magnetic force that acts from the yoke when the coil is energized.
The yoke is
The first sub yoke,
Wherein and the first sub yokes are spaced in the direction of the rotation axis of the rotor, possess a second sub-yokes which a permanent magnet is provided, and
The permanent magnet is
The alignment direction of the north pole and the south pole is disposed along one closed magnetic path which can be formed by the second sub yoke and the rotor.
Focal plane shutter for camera. Each of the first sub yoke and the second sub yoke is
Two legs parallel to each other,
And a connecting piece for connecting one ends of the two leg pieces.
In the rotor, a portion on one end side in the rotation axis direction is located between the other ends of the two leg pieces of the first sub yoke, and a portion on the other end side in the rotation axis direction is the Located between the other end of each of the two legs of the second sub-yoke,
The permanent magnet is embedded in the connection piece such that an alignment direction of an N pole and an S pole coincides with a direction from one of the two leg pieces to the other.
The focal plane shutter for a camera according to claim 1 . The yoke further comprises:
A shielding member interposed between the first sub-yoke and the second sub-yoke to shield an electromagnetic field in the first sub-yoke and an electromagnetic field in the second sub-yoke from each other;
The focal plane shutter for cameras according to claim 1 or 2 . The force acting on the rotor from the first sub yoke is greater than the force acting on the rotor from the second sub yoke when the coil is not energized.
The focal plane shutter for cameras according to any one of claims 1 to 3 . The first thickness in the rotation axis direction of the first sub yoke is thicker than the second thickness in the rotation axis direction of the second sub yoke.
The focal plane shutter for cameras according to claim 4 . A focal plane shutter for a camera according to any one of claims 1 to 5 .
A lens portion comprising one or more lenses;
A control unit that controls an operation of the camera focal plane shutter at the time of shooting;
A solid-state imaging device configured to convert light imaged through the lens unit into an electrical signal according to the operation of the camera focal plane shutter;
camera.