JP6484087B2 - Camera focal plane shutter and camera - Google Patents

Description

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

  2. Description of the Related Art Conventionally, a focal plane shutter for a camera includes a ground plane provided with an opening for irradiating light from a subject to a solid-state imaging device, and a plurality of blades attached to the ground plane so that the opening can be opened and closed. Various mechanisms have been proposed as mechanisms for driving the blades. For example, a focal plane shutter for a camera described in Patent Document 1 includes a coil and a rotor (rotor) that rotates by a magnetic force generated by the coil. The blade receives a driving force from the rotor and reciprocates between a fully open position where the entire opening is exposed and a fully closed position where the entire opening is closed.

JP 2012-215658 A

  In the configuration described in Patent Document 1, it is difficult to rotate the rotor at a rated speed immediately after the coil is energized, and the rotor gradually rotates faster after a current is passed through the coil. Therefore, immediately after moving from the fully open position toward the fully closed position, the moving speed of the blades is slow. Thereafter, as the blades accelerate, the moving speed of the blades gradually increases. As described above, when the moving speed changes during the movement of the blade, the exposure time of the individual image sensor changes depending on the area of the imaging surface of the individual image sensor, and as a result, the image quality of the captured image may deteriorate.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide a focal plane shutter for a camera and a camera capable of suppressing a speed change during movement of a blade.

In order to achieve the above object, a focal plane shutter for a camera according to a first aspect of the present invention includes:
A main plate having an opening;
An arm that pivots about a first axis fixed to the base plate and has a sliding hole portion that forms a long hole;
A blade that is connected to the arm and moves with the turning of the arm to change the state of the opening between a fully opened state in which the opening is opened and a fully closed state in which the opening is closed;
A main actuator that provides a force for the arm to pivot;
A sub-actuator for assisting the turning of the arm,
The sub-actuator is
A second rotor that rotates around a second axis that is parallel to the first axis and that is fixed to the ground plane at a position different from the first axis;
The fully-opened state and the fully-closed state are accommodated in the sliding hole portion from the first position corresponding to one of the fully-opened state and the fully-closed state as the second rotor rotates. A sliding portion that pivots with respect to the base plate to a second position corresponding to any one of
The sliding hole portion includes a first curved wall that contacts while the sliding portion moves from the first position to the second position;
The first curved wall includes a tangential direction of the first curved wall and a turning direction of the arm at a position where the sliding portion abuts while the sliding portion moves from the first position to the second position. It curves so that the angle made with becomes gradually smaller.

  In order to achieve the above object, a camera according to a second aspect of the present invention includes a focal plane shutter for a camera according to the first aspect of the present invention.

  According to the present invention, it is possible to suppress the speed change during the movement of the blades.

It is a block diagram which shows the functional structure of the focal plane shutter for cameras which concerns on one Embodiment of this invention. It is a front view of the focal plane shutter for cameras concerning one embodiment of the present invention. It is a front view of an actuator, a wing, and an arm concerning one embodiment of the present invention. It is a disassembled perspective view of the focal plane shutter for cameras concerning one embodiment of the present invention. It is a side view of the focal plane shutter for cameras concerning one embodiment of the present invention. It is an enlarged front view of an actuator, a blade | wing, and an arm when the shutter curtain which concerns on one Embodiment of this invention exists in a full open position. It is an enlarged front view of an actuator, a blade, and an arm when the shutter curtain according to one embodiment of the present invention is moving. It is an enlarged front view of an actuator, a blade | wing, and an arm when the shutter curtain which concerns on one Embodiment of this invention exists in a fully closed position. FIG. 9 is an enlarged view around the second rotor in FIG. 8. It is a graph which shows the transmission efficiency of the subactuator which concerns on one Embodiment of this invention. It is a flowchart which shows an example of the process sequence of the control circuit which concerns on one Embodiment of this invention. It is a front view of the focal plane shutter for cameras concerning other embodiments of the present invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The focal plane shutter for a camera according to the present embodiment is mounted on a camera such as a digital camera or a still camera.

<Configuration>
As shown in FIG. 1, the camera focal plane shutter system 1 includes a camera focal plane shutter (hereinafter also simply referred to as “shutter”) 2 and a control device 3 that controls the shutter 2. In the present embodiment, an example in which the shutter 2 is a single curtain shutter will be described.

  As shown in FIGS. 2 and 3, the shutter 2 is a so-called square shutter, and can operate the base plate 210 having the opening 211, the shutter curtain 150 that opens and closes the opening 211, and the base plate 210 and the shutter curtain 150. A first arm 141 and a second arm 142 to be connected, a main actuator 110 that applies operating force to the shutter curtain 150, and a subactuator 120 that applies operating force to the shutter curtain 150 to assist the main actuator 110 are provided.

  The base plate 210 is formed in a substantially rectangular plate shape, and a rectangular opening 211 penetrating in the thickness direction of the base plate 210 is formed in the center of the base plate 210. As shown in FIG. 4, a rectangular holder 220 is provided on the upper surface of the base plate 210 so as to be along the short direction of the opening 211. The holder 220 includes a box-shaped holder main body 220a whose upper side is open and a lid portion 220b attached to the upper surface of the holder main body 220a. On the lower surface of the base plate 210, an auxiliary plate (not shown) is overlapped with the base plate 210 so as to have a gap.

  As shown in FIG. 4, a first storage space 220e that forms a rectangular parallelepiped corresponding to the main actuator 110 and a second storage space 220f that forms a rectangular parallelepiped corresponding to the subactuator 120 are formed inside the holder main body 220a. Yes. The first storage space 220e and the second storage space 220f are arranged along the longitudinal direction of the holder body 220a.

  A through hole 220g through which the cylindrical shaft portion 222 is inserted is provided on the inner bottom surface of the holder main body 220a in the first storage space 220e, and a cylindrical shaft is formed on the inner bottom surface of the holder main body 220a in the second storage space 220f. A through hole 220h through which the portion 223 is inserted is provided. These shaft portions 222 and 223 are fixed to the upper surface of the main plate 210.

  The lower end of the side wall of the holder main body 220 a is fixed to the upper surface of the main plate 210, and the inner bottom plate of the holder main body 220 a is supported by these side walls so as to be separated from the upper surface of the main plate 210. The holder body 220a is fitted with the lid 220b from above in a state where the main actuator 110 and the sub-actuator 120 are accommodated.

  As shown in FIG. 4, the main actuator 110 is housed in the first housing space 220e, a U-shaped first yoke 112, a first coil 111 inserted through a part of the first yoke 112, And a first rotor 113 that rotates about a shaft portion 222 by a magnetic force generated by the first coil 111.

  As shown in FIGS. 3 and 4, the first rotor 113 is constituted by a cylindrical magnet inserted through the shaft portion 222. The first rotor 113 is alternately magnetized with N and S poles along the circumferential direction thereof, and rotates about the rotation axis J <b> 21 by a change in the magnetic field formed by the first coil 111. The rotation axis J21 passes through the center of the shaft portion 222.

  As shown in FIG. 3, the first yoke 112 is made of a magnetic material such as iron. The first yoke 112 is entirely U-shaped by a pair of extending portions 112a and 112b extending in a direction orthogonal to the rotation axis J21 of the first rotor 113 and a connecting portion 112c connecting the pair of extending portions 112a and 112b. Composed in a letter shape. The pair of extending portions 112a and 112b are separated in a direction perpendicular to the rotation axis J21 of the first rotor 113. Arc-shaped recesses corresponding to the outer periphery of the first rotor 113 are formed on the inner surfaces at the distal ends of the pair of extending portions 112a and 112b. A first rotor 113 is provided between the distal ends of the pair of extending portions 112a and 112b.

  As shown in FIGS. 3 and 4, the first coil 111 includes a rectangular cylindrical bobbin 111a and a winding 111b of a conductive material such as copper wound around the outer periphery of the bobbin 111a. As shown in FIG. 1, two conductive lines L <b> 11 and L <b> 12 extend from the winding 111 b to the outside of the first coil 111, and the conductive lines L <b> 11 and L <b> 12 are connected to the control device 3. The first coil 111 is inserted through the extended portion 112 a far from the shutter curtain 150 in the first yoke 112.

  As shown in FIG. 4, a rotating portion 116 that rotates integrally with the first rotor 113 and applies a rotational force to the shutter curtain 150 is attached to the lower end of the first rotor 113. The rotating part 116 extends in the radial direction of the first rotor 113 so as to be able to rotate integrally with the first rotor 113. Specifically, the rotating portion 116 includes a holding portion 116a that holds the first rotor 113 from its lower end, and a tip portion that extends in the radial direction of the first rotor 113 and is bent at a right angle from the tip toward the base plate 210. 116b. As shown in FIG. 4, the rotation part 116 extends to the lower side of the holder body 220a through a through hole 220g formed in the inner bottom plate of the holder body 220a. The holding part 116a of the rotating part 116 rotates between the holder main body 220a and the main plate 210 around the rotation axis J21 of the first rotor 113.

  As shown in FIGS. 3 and 4, the subactuator 120 is housed in the second housing space 220 f and, like the main actuator 110, the U-shaped second yoke 122 and a part of the second yoke 122. And a second rotor 123 that rotates about a shaft portion 223 by a magnetic force generated by the second coil 121. The sub-actuator 120 and the main actuator 110 are configured to be line symmetrical about the symmetry axis extending between the first storage space 220e and the second storage space 220f in a direction perpendicular to the rotation axis J21 of the first rotor 113. Yes. Since the configuration of each part of the sub-actuator 120 is the same as that of the main actuator 110, the description of common parts is omitted, and only the parts different from the main actuator 110 are described.

  As shown in FIG. 4, a rotating part 126 that rotates integrally with the second rotor 123 and applies a rotational force to the shutter curtain 150 is attached to the lower end of the second rotor 123. The rotating portion 126 includes a holding portion 126a attached to the lower end of the second rotor 123, and a columnar shape that extends in the radial direction of the second rotor 123 and has a tip bent at a right angle toward the main plate 210. And a sliding portion 126b. The holding part 126a is formed in a cylindrical shape so that the second rotor 123 can be held from below. The sliding portion 126b may be molded with a resin integrally with the holding portion 126a, or may be formed of metal separately from the holding portion 126a. When the sliding portion 126b is formed separately from the holding portion 126a, the sliding portion 126b is fixed to the holding portion 126a with a screw or an adhesive. The rotating part 126 extends to the lower side of the holder main body 220a through a through hole 220h formed in the inner bottom plate of the holder main body 220a, and the holding part 126a of the rotating part 126 extends between the holder main body 220a and the base plate 210. Rotate.

  As shown in FIG. 4, the base plate 210 is formed with a first long hole 213 and a second long hole 214 that penetrate in the thickness direction of the base plate 210. The first long hole 213 is formed so that the tip end portion 116b of the rotating portion 116 can be inserted from above, and has an arc shape corresponding to the movement locus of the tip end portion 116b accompanying the rotation of the first rotor 113. . The second long hole 214 is formed so that the sliding portion 126b of the rotating portion 126 can be inserted from above, and the sliding portion 126b is relative to the second arm 142 when the second rotor 123 rotates. It has an arc shape according to the movement trajectory. In the present embodiment, the end portion 214a on the opening 211 side of the second long hole 214 is an example of a stopper portion.

  As shown in FIGS. 3 and 5, the first arm 141 is located on the inner surface of the main plate 210, and operably connects the tip end portion 116 b of the rotating portion 116 and the blades 151, 152, 153, and 154. ing. The second arm 142 is located on the inner surface of the base plate 210 and operatively connects the sliding portion 126b of the rotating portion 126 and the blades 151, 152, 153, and 154. The first arm 141 and the second arm 142 have a shape in which the tip is bent as viewed from the thickness direction. The configuration of the connecting portion between the first arm 141 and the rotating portion 116 and the connecting portion between the second arm 142 and the rotating portion 126 will be described in detail later.

  As shown in FIG. 3, the shutter curtain 150 is composed of four blades 151, 152, 153, and 154. Each blade | wing 151,152,153,154 is formed in the substantially rectangular plate shape. As shown in FIGS. 2 and 5, the shutter curtain 150 is arranged on the inner surface side of the main plate 210 and is configured to be able to open and close the opening 211. Specifically, as shown in FIG. 8, the four blades 151, 152, 153, and 154 are connected to the first arm 141 and the second arm 142 by pins 141a, 141b, 141c, 141d, 142a, 142b, 142c, It is rotatably connected through 142d. The four pins 141a, 141b, 141c, 141d related to the first arm 141 are arranged in order from the tip side of the first arm 141. Similarly, the four pins 141a, 141b, 141c, 141d related to the second arm 142 are The two arms 142 are arranged in order from the tip side.

  As shown in FIG. 8, the blade 151 is rotatably connected to the first arm 141 and the second arm 142 via two pins 141a and 142a. The blade 152 is rotatably connected to the first arm 141 and the second arm 142 via two pins 141b and 142b. The blade 153 is rotatably connected to the first arm 141 and the second arm 142 via two pins 141c and 142c. The blade 154 is rotatably connected to the first arm 141 and the second arm 142 via two pins 141d and 142d.

  The shutter curtain 150 changes between a fully open state and a fully closed state with respect to the opening 211 of the main plate 210 via the first arm 141 and the second arm 142 by driving the main actuator 110 and the subactuator 120. When the shutter curtain 150 is in the fully open state, the plurality of blades 151, 152, 153, and 154 are in the fully open position, and when the shutter curtain 150 is in the fully closed state, the plurality of blades 151, 152, 153, and 154 are fully open. Exists in the closed position. As shown in FIGS. 2 and 6, in the fully open position, the plurality of blades 151, 152, 153, and 154 are arranged at the lower edge (on the main actuator 110 side) of the opening 211 of the base plate 210 when viewed from the thickness direction of the base plate 210. Are overlapped with each other in the retracted state. When the plurality of blades 151, 152, 153, 154 are in the fully open position, the entire area of the opening 211 is exposed to the outside.

  The blades 151, 152, 153, and 154 move sequentially from the fully open position toward the upper edge of the opening 211 of the main plate 210 (edge on the subactuator 120 side). As a result, the opening 211 is closed by the blades 151, 152, 153, and 154. As shown in FIG. 8, when the blade 151 comes into contact with the upper edge of the opening 211 of the base plate 210, the shutter curtain 150 is in the fully closed position. In the fully closed position, the plurality of blades 151, 152, 153, and 154 cover the entire area of the opening 211 of the main plate 210.

  Next, the structure of the connection part of the 1st arm 141 and the rotation part 116 and the connection part of the 2nd arm 142 and the rotation part 126 is demonstrated.

  As shown in FIG. 7, a rectangular fitting hole 141 e penetrating in the thickness direction of the first arm 141 is formed at the base end portion of the first arm 141. The front end portion 116b of the rotating portion 116 is fitted in the fitting hole 141e.

  A shaft through hole 142 e into which the shaft portion 143 is inserted is formed at the base end portion of the second arm 142. The rotation axis J23 (first axis) of the second arm 142 is different from the rotation axis J22 (second axis) of the second rotor 123, in this embodiment, relative to the rotation axis J22 of the second rotor 123. It is located in a direction away from the second arm 142.

  As shown in FIG. 6, a sliding hole portion 145 having a long hole penetrating in the thickness direction of the second arm 142 is formed at the base end portion of the second arm 142 in addition to the shaft through hole 142 e. Yes. The sliding hole portion 145 forms a long hole extending substantially in an arc shape when viewed from the thickness direction of the second arm 142. The sliding hole portion 145 follows the locus of relative movement of the sliding portion 126b with respect to the second arm 142 so that the second arm 142 and the sliding portion 126b of the second rotor 123 can be linked. Is formed. Specifically, the sliding hole portion 145 includes a first curved wall 145a and a second curved wall 145b that are spaced apart from each other, and a first connecting the first curved wall 145a and the second curved wall 145b at both ends thereof. It consists of an end wall 145c and a second end wall 145d. The first curved wall 145a and the second curved wall 145b are made of curved wall surfaces, and face each other while being separated by a distance larger than the diameter of the sliding portion 126b of the rotating portion 126. Each end wall 145c, 145d forms a semicircular wall surface corresponding to the outer periphery of the sliding portion 126b of the rotating portion 126. The first end wall 145c is located at the end of the sliding hole 145 that faces the outer side in the radial direction of the second rotor 123, and the second end wall 145d is the second arm 142 in the sliding hole 145. Is located at the end of the extension. A sliding portion 126b located inside the main plate 210 is inserted through the sliding hole portion 145.

  As shown in FIG. 1, the control device 3 includes a control circuit 3a composed of a CPU (Central Processing Unit), a storage unit 3b composed of a memory, and a timer 3c composed of a hardware timer or a software timer. An input unit 5 that outputs an operation signal based on a user's pressing operation is connected to the control circuit 3a.

<Control procedure>
When receiving the operation signal from the input unit 5, the control circuit 3a operates the shutter 2 by reading and executing the program stored in the storage unit 3b. Hereinafter, this program will be described with reference to the flowchart of FIG. This program is executed to displace the shutter curtain 150 from the fully open position to the fully closed position.

  When the shutter curtain 150 is in the fully open position, when receiving an operation signal from the input unit 5, the control circuit 3a supplies a current in the first direction to the first coil 111 via the conductive lines L11 and L12, and the conductive line. A current in the first direction is supplied to the second coil 121 via L21 and L22 (step S101). At this time, as shown in FIG. 11, the first coil 111 and the second coil 121 form magnetic poles around the first rotor 113 and the second rotor 123 as electromagnets. As a result, the first rotor 113 and the second rotor 123 receive the repulsive force or the attractive force generated between the corresponding first coil 111 and the second coil 121 and rotate clockwise in FIG. It rotates in the first direction B1.

  As shown in FIG. 11, the control circuit 3a waits for a predetermined time T1 from the start of energization of the first coil 111 and the second coil 121 through the timer 3c (NO in step S102). The predetermined time T1 is set in advance to a time required for the shutter curtain 150 to reach the fully closed position from the fully open position. When determining that the predetermined time T1 has elapsed (YES in step S102), the control circuit 3a stops energization to the first coil 111 and switches the energization direction to the second coil 121 (step S103). That is, a current in a second direction opposite to the first direction is supplied to the second coil 121. Then, the control circuit 3a waits for a predetermined time T2 to elapse from the start of energization of the second coil 121 in the second direction (NO in step S104). As will be described later with reference to FIG. 8, this fixed time T2 is the time required for the sliding portion 126b of the rotating portion 126 to move from the second position Pb to the third position Pc in the sliding hole portion 145. Is set to When the control circuit 3a determines that the predetermined time T2 has elapsed (YES in step S104), the control circuit 3a stops energizing the second coil 121 (step S105). As described above, the control circuit 3a can displace the shutter curtain 150 from the fully open position to the fully closed position, and can lock the shutter curtain 150 in the fully closed position.

  On the contrary, in order to move the shutter curtain 150 from the fully closed position to the fully open position, the control circuit 3a first supplies a current in the first direction to the second coil 121 for a predetermined time T2, and then the first coil. A current in the second direction is supplied to the first coil 111 and the second coil 121 for a predetermined time T1. Accordingly, the sliding portion 126b of the rotating portion 126 moves toward the first position Pa after moving from the third position Pc to the second position Pb in the sliding hole portion 145. For this reason, the shutter curtain 150 moves from the fully closed position to the fully open position. The control circuit 3a does not have to energize the second coil 121 when moving the shutter curtain 150 from the fully closed position to the fully open position.

<Operation>
Here, the movement of the sliding hole 145 when the shutter curtain 150 moves will be described first, and then the operation of the shutter 2 when the program is executed will be described.

  As shown in FIGS. 6 to 8, the sliding hole portion 145 rotates around the rotation axis J <b> 23 together with the second arm 142 in which the sliding hole portion 145 is formed, and the sliding portion of the rotating portion 126. 126b rotates around the rotation axis J22 together with the second rotor 123. For this reason, the sliding hole portion 145 is configured to change the posture with respect to the second rotor 123 in accordance with the rotational positions of the second arm 142 and the second rotor 123.

  Specifically, as shown in FIG. 6, when the shutter curtain 150 is in the fully open position, the sliding hole portion 145 faces the rotation axis J23 of the second arm 142 with the second rotor 123 interposed therebetween. To position. At this time, the first curved wall 145a and the second curved wall 145b on the first end wall 145c side are orthogonal to the turning direction A1 of the second arm 142, and the first curved wall 145a and the second curved wall on the second end wall 145d side. The wall 145b is along the turning direction A1 of the second arm 142.

  As shown in FIG. 7, when the shutter curtain 150 moves from the fully open position toward the fully closed position by a predetermined distance, the sliding hole portion 145 faces the first rotor 113 with the second rotor 123 interposed therebetween. Is located. As shown in FIG. 8, when the shutter curtain 150 reaches the fully closed position, the sliding hole 145 is positioned so as to face the first rotor 113 with the rotation axis J23 of the second arm 142 interposed therebetween. To do. As the shutter curtain 150 moves toward the fully closed position, the sliding hole 145 revolves around the rotation axis J23 of the second arm 142 while rotating clockwise.

  Next, the mechanical operation of the shutter 2 when the above program is executed will be described.

  As shown in FIG. 6, when the shutter curtain 150 is in the fully open position, the first rotor 111 and the second rotor 123 are turned clockwise in FIG. 6 by energizing the first coil 111 and the second coil 121. Rotate in one direction B1. The rotational force of the first rotor 113 is transmitted to the first arm 141 and the blades 151, 152, 153 and 154 through the rotating part 116. The rotational force of the second rotor 123 is applied to the first arm 141 and the blades 151, 152, 153, and 154 via the sliding part 126 b of the rotating part 126 in order to assist the rotational force of the first rotor 113. Communicated. Each blade 151, 152, 153, 154 changes between the fully open state and the fully closed state as the first arm 141 and the second arm 142 rotate.

  For example, as shown in FIG. 6, when the shutter curtain 150 is in the fully open position, the sliding portion 126 b of the rotating portion 126 is in the first position Pa that is in contact with the first end wall 145 c in the sliding hole portion 145. Located in. At this time, the first curved wall 145a and the second curved wall 145b on the first end wall 145c side are positioned so as to be orthogonal to the turning direction A1 of the second arm 142. Therefore, when the rotating part 126 rotates in the first direction B1 together with the second rotor 123, the wall surface at the position where the sliding part 126b of the rotating part 126 contacts the first curved wall 145a. The force F1 is applied in a direction perpendicular to the tangential direction. This force F1 acts in a direction that coincides with the turning direction A1 of the second arm 142. For this reason, as shown in FIG. 10, at the time t0 when the shutter curtain 150 is in the fully open state, the rotational force of the second rotor 123 is the second arm 142 with the maximum transmission efficiency Em as the rotational force of the second arm 142. 142.

  As shown in FIG. 7, as the second arm 142 rotates about the rotation axis J23 and the first arm 141 rotates about the rotation axis J21, the blades 151, 152, 153, and 154 expand. . Here, since the rotation axis J23 of the second arm 142 and the rotation axis J22 of the rotating portion 126 are different, the rotation of the second arm 142 within the sliding hole portion 145 of the second arm 142 occurs. The sliding part 126b of the moving part 126 moves. In other words, when the sliding portion 126b of the rotating portion 126 moves within the sliding hole portion 145, the second arm 142 and the rotating portion 126 having different rotation axes can be linked.

  As shown in FIG. 7, when the sliding portion 126b of the rotating portion 126 is rotated from the first position Pa in the first direction B1 by energizing the second coil 121, the rotation of the first arm 141 and the second arm 142 is performed. In addition, from the first position Pa where the sliding portion 126b of the rotating portion 126 contacts the first end wall 145c (first end) in the sliding hole portion 145, the second end wall 145d (second end portion). ) Along the first curved wall 145a. The first curved wall 145a and the second curved wall 145b are formed so as to incline in a direction along the turning direction A1 of the second arm 142 toward the second end wall 145d. Therefore, as the sliding part 126b moves from the first position Pa to the second position Pb located on the second end wall 145d side, the tangential direction of the first curved wall 145a at the position where the sliding part 126b comes into contact with the second position Pb. The angle formed by the turning direction A1 of the two arms 142 becomes smaller. Along with this, the vector of the force F1 applied to the first curved wall 145a by the sliding portion 126b of the rotating portion 126 rotates in the direction toward the rotation axis J23 of the second arm 142. For this reason, when the sliding portion 126b breaks down the component of the force F1 applied to the first curved wall 145a, the component force F2 acting in the turning direction A1 of the second arm 142 decreases, and the rotation axis J23 of the second arm 142 decreases. The component force F3 acting in the direction increases. Therefore, as shown in FIG. 10, as the deployment of the shutter curtain 150 proceeds from time t 0, the transmission efficiency E is such that the rotational force of the second rotor 123 is transmitted to the second arm 142 as the rotational force of the second arm 142. Gradually decreases. As the transmission efficiency E decreases, excessive acceleration of the first arm 141 and the second arm 142, and thus the shutter curtain 150, is suppressed.

  As shown in FIG. 8, when the shutter curtain 150 reaches the fully closed position, the sliding portion 126b of the rotating portion 126 is slightly closer to the center in the extending direction of the sliding hole portion 145 and slightly closer to the second end wall 145d. Located at 2 position Pb. When the sliding portion 126b is in the second position Pb, there is a gap between the sliding portion 126b and the second curved wall 145b of the sliding hole portion 145, so that the sliding portion 126b is counterclockwise. It can rotate in two directions B2. In other words, the sliding hole portion 145 extends from the second position Pb toward the second end portion 145d toward the second direction B2. When the sliding portion 126b rotates in the second direction B2 from the second position Pb, the sliding portion 126b of the rotating portion 126 moves in the sliding hole portion 145 toward the second end wall 145d side while moving to the first curve. The position moves from the position in contact with the wall 145a to the third position Pc in contact with the second curved wall 145b. At this time, since only the sliding part 126 b is moving in the sliding hole part 145 of the second arm 142 stopped, the rotating part 126 does not give any force to the second arm 142. When viewed from the rotation axis J22 of the second rotor 123, the third position Pc is located between the first position Pa and the second position Pb.

As shown in an enlarged view in FIG. 9, at the third position Pc, the sliding portion 126b of the rotating portion 126 abuts on the lock surface 145e of the sliding hole portion 145, and as an example of the stopper portion shown in FIG. It abuts on the end 214a of the second long hole 214 formed in the main plate 210. The lock surface 145e is a part of the first curved wall 145a on the second end wall 145d side. When the sliding portion 126b reaches the third position Pc, the perpendicular of the lock surface 145e (the line extending on the line of the force Fa in FIG. 9) passes the shutter curtain 150 side from the rotation axis J22 of the second rotor 123. To do. The end portion 214a of the second long hole 214 indicates that the sliding portion 126b at the third position Pc moves in the second direction B2 (direction toward the first position Pa as viewed from the rotation axis J22 of the second rotor 123). And restricting through contact with the sliding part 126b. When the sliding part 126b is in the third position Pc, a gap is formed between the sliding part 126b and the second end wall 145d of the sliding hole part 145.
Here, when the blades 151, 152, 153, 154 reach the fully closed position, the blade 151 collides with the edge of the opening 211 at a predetermined speed. Thereby, a bounding force F4 acts on the blades 151, 152, 153, 154, the first arm 141, and the second arm 142 toward the fully open position. When this sliding force 126 is applied to the second arm 142 when the sliding part 126b of the rotating part 126 is at the third position Pc, the rotational force of the second arm 142 is applied to the rotating part via the lock surface 145e. The sliding part 126b of 126 receives. At this time, the lock surface 145e presses the sliding portion 126b with a force Fa toward the shutter curtain 150 from the rotation axis J22 of the second rotor 123. The force Fa applied to the sliding portion 126b is decomposed into a component force Fb toward the rotation axis J22 of the second rotor 123 and a component force Fc toward the second end wall 145d of the sliding hole portion 145. The component force Fb does not cause a force to rotate the second rotor 123, and the component force Fc strongly presses the sliding portion 126b against the end 214a of the second long hole 214 formed in the base plate 210. Therefore, even when the bounding force F4 is applied, the sliding portion 126b is maintained at the third position Pc.

<Effect>
The focal plane shutter for a camera according to the above embodiment has the following effects.

  (1) The first curved wall 145a has the tangential direction of the first curved wall 145a and the second arm 142 at a position where the sliding portion 126b contacts as the sliding portion 126b moves from the first position Pa to the second position Pb. It is curved so that the angle formed by the turning direction A1 is small. For example, when the shutter curtain 150 is in the fully open position, the angle formed by the tangential direction of the first curved wall 145a and the turning direction A1 of the second arm 142 at the position where the sliding portion 126b contacts is 90 °. At this time, the turning direction A1 of the second arm 142 coincides with the direction of the force F1 transmitted by the sliding portion 126b to the second arm 142. Therefore, the first curved wall 145a can transmit the rotational force of the sliding portion 126b by the subactuator 120 to the second arm 142 with high efficiency as the rotational force of the second arm 142. Therefore, the subactuator 120 can quickly increase the speed of the shutter curtain 150 immediately after the blades 151, 152, 153, and 154 start moving.

  Further, as the shutter curtain 150 is deployed, the sliding portion 126b of the subactuator 120 moves from the first position Pa on the first end wall 145c side to the second position Pb on the second end wall 145d side in the sliding hole portion 145. Move towards. As a result, the angle formed by the tangential direction of the first curved wall 145a and the turning direction A1 of the second arm 142 at the position where the sliding portion 126b contacts is gradually reduced. Therefore, of the force F1 applied to the second arm 142 by the sliding portion 126b of the subactuator 120, the component force F2 acting in the turning direction of the second arm 142 is reduced. Therefore, as the shutter curtain 150 is deployed and the blades 151, 152, 153, and 154 are accelerated, the rotational force that the subactuator 120 applies to the second arm 142 gradually decreases. For this reason, it is suppressed that the shutter curtain 150 moves exceeding a desired speed.

As described above, the rotational force transmitted from the subactuator 120 to the second arm 142 is changed in accordance with the deployed position of the shutter curtain 150, thereby suppressing the speed change during the movement of the blades 151, 152, 153, and 154. It becomes possible to do.
Further, when the shutter curtain 150 approaches the fully closed position, excessive acceleration of the shutter curtain 150 is suppressed, so that when the shutter curtain 150 reaches the fully closed position, the shutter curtain 150 reaches the edge of the opening 211. The bounce force F4 applied to the shutter curtain 150 due to the collision can also be reduced.

  (2) When the shutter curtain 150 is in the fully closed position, the first curved wall 145a is struck by the sliding portion 126b as the second rotor 123 rotates in the second direction B2 (counterclockwise in FIG. 9). It includes a locking surface 145e that contacts. When a rotational force is applied to the second arm 142 by the bound force F4 in a state where the sliding portion 126b is in contact with the lock surface 145e, the lock surface 145e is separated in the direction of the rotation axis J22 of the second rotor 123. The sliding part 126b is pressed so that the force Fb acts. For this reason, it is suppressed that the sliding part 126b rotates centering around the rotating shaft J22 of the 2nd rotor 123, and bounce force F4 was added to the 2nd arm 142 via the blade | wings 151,152,153,154. Even in this case, the rotation of the second arm 142 is restricted, and the bounce of the blades 151, 152, 153, and 154 connected to the second arm 142 can be suppressed.

  (3) The end portion 214a of the second long hole 214, which is an example of a stopper portion, regulates the movement of the sliding portion 126b in the third position Pc in the second direction B2 through contact with the sliding portion 126b. . In the state where the sliding portion 126b is in contact with the lock surface 145e, when a rotational force is applied to the second arm 142 by the bound force F4, the lock surface 145e is connected to the rotation axis J22 of the second rotor 123 and the second length. The sliding portion 126b is pressed with the force Fa so that the component forces Fb and Fc are applied to the end portion 214a of the hole 214, respectively. Depending on the component force Fb, no force is generated to rotate the second rotor 123, and the sliding portion 126b is more strongly pressed against the main plate 210 by the component force Fc. For this reason, even when the bounding force F4 is applied, the sliding portion 126b is maintained at the third position Pc, and the rotation of the second arm 142 is restricted by the sliding portion 126b.

  (4) The end portion 214a of the second long hole 214 is an example of a stopper portion that restricts movement of the sliding portion 126b in the third position Pc toward the second direction B2 through contact with the sliding portion 126b. Configured as Thus, by providing the stopper portion on the base plate 210, the sliding portion 126b can be stopped at the third position Pc with higher accuracy.

  When the sliding portion 126b reaches the third position Pc, the sliding portion 126b comes into contact with the end portion 214a of the second long hole 214 before the second end wall 145d of the sliding hole portion 145. For this reason, in order to stop the sliding part 126b in the 3rd position Pc, the high shape precision and assembly | attachment precision are not requested | required of the sliding hole part 145 of the 2nd arm 142, and manufacturability improves.

  (5) In this embodiment, the rotational force transmitted from the subactuator 120 to the second arm 142 is adjusted by the mechanical configuration, for example, the shape and arrangement of the sliding portion 126b and the sliding hole portion 145. . Therefore, the control of the control device 3 is not complicated.

  (6) The moving speed of the shutter curtain 150 is controlled by the subactuator 120. Therefore, it is not necessary to suppress the output of the main actuator 110 in order to control the moving speed of the shutter curtain 150, and the moving speed of the shutter curtain 150 can be increased.

(Modification)
In the above embodiment, the lock surface 145e is formed in the sliding hole portion 145 for bounce suppression, but the lock surface 145e may be omitted. In this case, the sliding hole portion 145 has a shape in which a part on the second end wall 145d side is omitted. In this configuration, the control circuit 3a stops energization to the first coil 111 and the second coil 121 instead of step S103 after steps S101 and S102 in FIG. Thereafter, the program for developing the shutter curtain 150 is terminated without executing the processes of steps S104 and S105.

  In the above-described embodiment, the camera focal plane shutter is a single-curtain type shutter having one shutter curtain. For example, the camera focal plane shutter is a two-curtain type focal plane having two shutter curtains. It may be a shutter.

  For example, as shown in FIG. 12, in the two-curtain type focal plane shutter, a rear curtain device 300 and a front curtain device 400 are arranged with respect to one base plate 210. The rear curtain device 300 and the front curtain device 400 have the same configuration, and specifically have the same configuration as the shutter 2 of the above embodiment. The front curtain device 400 is arranged in a direction rotated by 180 ° with respect to the rear curtain device 300 about the rotation axis J22 of the second rotor 123 as a rotation center. The shutter curtain 150 of the front curtain device 400 and the shutter curtain 150 of the rear curtain device 300 are arranged to face each other with the opening 211 therebetween. In this configuration, the control circuit first changes the shutter curtain 150 of the front curtain device 400 from the fully open state to the fully closed state, and then again to the fully open state. Thereafter, when a preset time elapses, the control circuit changes the shutter curtain 150 of the rear curtain device 300 from the fully open state to the fully closed state, and then returns to the fully open state again. For example, when the imaging device is disposed opposite to the opening 211 of the focal plane shutter for the camera, the imaging device is configured such that the shutter curtain 150 of the rear curtain device 300 is changed after the shutter curtain 150 of the front curtain device 400 is changed from the fully closed state to the fully opened state. The image can be captured during the time until the fully closed state.

  In the above embodiment, the example in which the shutter curtain 150 includes the four blades 151, 152, 153, and 154 has been described. However, the number of blades configuring the shutter curtain is not limited to four. There may be fewer than four or more than four.

  In the above embodiment, an example in which one shutter curtain 150 functions as a rear curtain has been described. However, for example, one shutter curtain 150 may be driven as a front curtain and then driven as a rear curtain.

  In the above embodiment, the control circuit 3a determines that the shutter curtain 150 has reached the fully closed position after a certain time T1 has elapsed from the start of the movement of the shutter curtain 150 in the fully open position. It may be determined that the curtain 150 has reached the fully closed position. For example, a detection switch that is pressed by the shutter curtain 150 when the shutter curtain 150 reaches the fully closed position is newly provided in the shutter 2. The control circuit 3a may determine that the shutter curtain 150 has reached the fully closed position based on the detection result of the detection switch.

  In the above embodiment, two arms are provided, but the number of arms is not limited to this, and may be one or three or more. When there is a single arm, the main actuator 110 and the sub-actuator 120 are each configured to apply a rotational force to the single arm.

In the above-described embodiment, the end 214a of the second long hole 214 receives a part of the force from the sliding portion 126b at the third position Pc and restricts the movement of the sliding portion 126b in the second direction B2. The second end wall 145d of the sliding hole portion 145 may constitute the stopper portion instead of the end portion 214a of the second long hole 214 or together with the end portion 214a. . Further, this stopper portion may be omitted. Even in this case, the lock surface 145 e presses the sliding portion 126 b at the third position Pc toward the second rotor 123. Thereby, rotation of the sliding part 126b is suppressed.
In the above embodiment, the sub-actuator 120 can assist the rotational force applied to the second arm 142 when the shutter curtain 150 moves from the fully open position to the fully closed position. However, conversely, when the shutter curtain 150 moves from the fully closed position to the fully open position, the sub-actuator 120 may be configured to be able to assist the rotational force applied to the second arm 142. In this case, the shutter curtain 150 is fully closed at the position of the arm shown in FIG. 7, and the shutter curtain 150 is fully opened at the position of the arm shown in FIG.

DESCRIPTION OF SYMBOLS 1 ... Camera focal plane shutter system, 2 ... Shutter, 3 ... Control apparatus, 3a ... Control circuit, 3b ... Memory | storage part, 3a ... Control circuit, 3c ... Timer, 110 ... Main actuator, 111 ... 1st coil, 112 ... Yoke, 113 ... first rotor, 120 ... subactuator, 121 ... second coil, 122 ... yoke, 123 ... second rotor, 126 ... rotating part, 126a ... holding part, 126b ... sliding part, 141 ... 1st arm, 145 ... sliding hole, 145a ... 1st curved wall, 145b ... 2nd curved wall, 145c ... 1st end wall, 145d ... 2nd end wall, 145e ... lock surface, 150 ... shutter curtain, 151 , 152, 153, 154 ... blades, 210 ... ground plane, 211 ... opening.

Claims (5)

A main plate having an opening;
An arm that pivots about a first axis fixed to the base plate and has a sliding hole portion that forms a long hole;
A blade that is connected to the arm and moves with the turning of the arm to change the state of the opening between a fully opened state in which the opening is opened and a fully closed state in which the opening is closed;
A main actuator that provides a force for the arm to pivot;
A sub-actuator for assisting the turning of the arm,
The sub-actuator is
A second rotor that rotates around a second axis that is parallel to the first axis and that is fixed to the ground plane at a position different from the first axis;
The fully-opened state and the fully-closed state are accommodated in the sliding hole portion from the first position corresponding to one of the fully-opened state and the fully-closed state as the second rotor rotates. A sliding portion that pivots with respect to the base plate to a second position corresponding to any one of
The sliding hole portion includes a first curved wall that contacts while the sliding portion moves from the first position to the second position;
The first curved wall includes a tangential direction of the first curved wall and a turning direction of the arm at a position where the sliding portion abuts while the sliding portion moves from the first position to the second position. A focal-plane shutter for a camera that curves so that the angle between and becomes gradually smaller. The sliding portion turns with respect to the ground plane by turning in a direction opposite to the turning direction when moving from the first position to the second position as the second rotor rotates. Moving from the second position to a third position between the first position and the second position;
Furthermore, when the sliding portion moves from the second position to the third position, one end portion located close to the both ends of the sliding hole portion when positioned at the second position. Move inside the sliding hole so as to get closer to
The sliding hole portion includes a lock surface that comes into contact with the sliding portion positioned at the third position among the second curved walls facing the first curved wall;
The camera focal according to claim 1, wherein the lock surface is formed so as to press the sliding portion positioned at the third position in a direction in which a force directed to the second axis is applied to the sliding portion. Plain shutter. A stopper portion for restricting movement of the sliding portion in contact with the lock surface toward the first position;
The focal plane shutter for a camera according to claim 2, wherein the lock surface is formed so as to press the sliding portion in a direction in which a component force toward each of the second shaft and the stopper portion is applied to the sliding portion. . The said base plate, said sliding part is inserted, the sliding portion which is the insertion elongated hole for moving are formed,
The stopper portion, the camera focal plane shutter according to claim 3 which is an end portion of the front SL slot. Comprising the focal plane shutter for a camera according to any one of claims 1 to 4,
camera.

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