JP2016161727A - Camera focal plane shutter system and camera focal plane shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera focal plane shutter system, camera focal plane shutter and camera that can achieve miniaturization.SOLUTION: A camera focal plane shutter 1 includes a driving gear 131, and two output gears 114 and 124. The driving gear 131 is integrally provided with arms 141 and 142, in which a rotation shaft J1 agrees with a central shaft of a shaft section 143. The output gear 114 engages with the driving gear 131, in which a rotation shaft J21 agrees with the rotation shaft J21 of a first rotator 113, and the output gear 114 is rotated in conjunction with the first rotator 113. The output gear 124 engages with the driving gear 131, in which a rotation shaft J22 agrees with the rotation shaft J22 of a second rotator 123, and the output gear 124 is rotated in conjunction with the second rotator 123.SELECTED DRAWING: Figure 1

Description

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

  A focal plane shutter for a camera generally includes a ground plate provided with an opening for irradiating light from a subject to a solid-state imaging device, and a blade attached to the ground plate so that opening / closing of the opening can be changed. Various mechanisms have been proposed as mechanisms for driving the blades. For example, Patent Document 1 drives the blades using an actuator that rotates the rotor (rotor) by the magnetic force generated by the coil. A mechanism has been proposed.

JP 2012-215658 A

  By the way, in recent cameras, there are demands such as an increase in the size of an image sensor and an increase in shutter speed. When a large image sensor is mounted, the opening of the ground plane also increases according to the size of the image sensor, and the blades for opening and closing it also increase. The larger the blade, the heavier the blade. Therefore, it is necessary to increase the driving force for driving the blades by the actuator. Further, in order to realize a high shutter speed, it is desired to increase the moving acceleration of the blade, so that it is necessary to increase the driving force for driving the blade by the actuator.

  As a method for increasing the driving force for driving the blades by the actuator, it is conceivable to increase the rotor and yoke constituting the actuator or increase the number of windings constituting the coil. Here, the yoke is made of a magnetic material and has a function of causing a magnetic force generated by a coil wound around a part of the yoke to act on the rotor. As the size of the yoke increases, the winding diameter of the coil also increases, and the overall size of the coil also increases.

  However, in such a method, the size of the entire actuator is increased, which leads to an increase in the size of the camera focal plane shutter system and camera focal plane shutter.

  In general, when the number of turns of the coil is increased, the winding is wound at a position away from the yoke, so that the winding efficiency is lowered. For this reason, for example, to increase the electromagnetic force while adopting the same magnetic rotor and the same size yoke, it is usually not sufficient to increase the number of windings in proportion to the electromagnetic force to be increased. The number of turns more than the magnification to be used is required, and the volume of the coil increases.

  Further, when the number of turns of the coil winding is increased, the cross-sectional area of the coil is increased, and as a result, the responsiveness at the start-up may be deteriorated as a result of an increase in inductance.

  The present invention has been made in view of the above circumstances, and provides a focal plane shutter system for a camera, a focal plane shutter for a camera, and a camera capable of driving a blade with a large driving force while reducing the size. For the purpose.

In order to achieve the above object, a focal plane shutter system for a camera according to the present invention comprises:
A main plate provided with a shaft portion having an opening and rotatably supporting an arm on an outer peripheral portion of the opening;
A shutter curtain connected to the arm and capable of taking a first state retracted to an outer peripheral portion of the opening of the base plate and a second state covering the opening of the base plate by turning the arm around the shaft portion. When,
A first actuator having a first rotor that rotates on a rotating shaft parallel to the shaft portion by a magnetic force generated by a first coil wound around a part of the first yoke;
A second actuator having a second rotor that rotates on a rotation axis parallel to the shaft portion by a magnetic force generated by a second coil wound around a part of the second yoke;
A main gear fixed to the arm and having a rotation axis coinciding with the central axis of the shaft portion;
A first sub-gear that meshes with the main gear, and whose rotation axis coincides with the rotation axis of the first rotor and rotates in conjunction with the first rotor;
A focal plane shutter for a camera having a second sub gear that meshes with the main gear and has a rotation axis that coincides with the rotation axis of the second rotor and rotates in conjunction with the second rotor;
A shutter control device that controls the operation of the shutter curtain by supplying voltage or current to the first coil and the second coil.

Further, a focal plane shutter system for a camera according to the present invention includes:
The shutter control device comprises:
Regarding the first rotor, the second rotor, the main gear, the first sub gear, and the second sub gear, the state of the shutter curtain is one of the first state and the second state. The state of the shutter curtain is changed from the one state to the other state when the rotation direction at the time of transition from the state to the other state is the main rotation direction and the rotation direction opposite to the main rotation direction is the reverse rotation direction. When the first rotor is in the one state immediately before shifting to the first rotor, the first rotor generates the first reverse rotation torque, the second rotor generates the second rotation forward torque,
The magnitude of the first torque may be greater than the magnitude of the second torque.

Further, a focal plane shutter system for a camera according to the present invention includes:
The shutter control device comprises:
Regarding the first rotor, the second rotor, the main gear, the first sub gear, and the second sub gear, the state of the shutter curtain is one of the first state and the second state. The state of the shutter curtain is changed from the one state to the other state when the rotation direction at the time of transition from the state to the other state is the main rotation direction and the rotation direction opposite to the main rotation direction is the reverse rotation direction. In the middle of shifting to, the third rotor generates the third torque of the reverse rotation, the second rotor generates the fourth torque of the forward rotation,
The magnitude of the third torque may be smaller than the magnitude of the fourth torque.

Further, a focal plane shutter system for a camera according to the present invention includes:
The shutter control device comprises:
A driving circuit for driving the focal plane shutter for the camera;
A control circuit for controlling the drive circuit;
A power supply for supplying power to the drive circuit and the control circuit,
The drive circuit is
A polarity switching circuit for individually switching the polarity of the voltage supplied to the first coil and the second coil;
A voltage changing circuit for changing the magnitude of the voltage supplied to the first coil and the second coil,
The modification circuit is
A voltage dividing circuit formed by connecting a plurality of resistors in series;
And a switching element that is connected in parallel to a part of the plurality of resistors and bypasses a part of the plurality of resistors when in an ON state.

Further, a focal plane shutter system for a camera according to the present invention includes:
In the first actuator and the second actuator, when the same voltage or current is supplied to the first coil and the second coil, the torque generated in the first rotor is the second actuator. It may be configured to be larger than the torque generated in the rotor.

Further, a focal plane shutter system for a camera according to the present invention includes:
The shutter control device comprises:
Regarding the first rotor, the second rotor, the main gear, the first sub gear, and the second sub gear, the state of the shutter curtain is one of the first state and the second state. Assuming that the rotation direction at the time of transition from the state to the other state is the main rotation direction, and the rotation direction opposite to the main rotation direction is the reverse rotation direction, the state of the shutter curtain changes from the one state to the other state. During the transition, the first rotor is caused to generate the forward rotation of the fifth torque, the second rotor is caused to generate the reverse rotation of the sixth torque,
The magnitude of the fifth torque may be greater than the magnitude of the sixth torque.

  The present invention may be a camera including any one of the above-described focal plane shutter systems for cameras.

The focal plane shutter for a camera according to the present invention is:
A main plate provided with a shaft portion having an opening and rotatably supporting an arm on an outer peripheral portion of the opening;
A shutter curtain connected to the arm and capable of taking a first state retracted to an outer peripheral portion of the opening of the base plate and a second state covering the opening of the base plate by turning the arm around the shaft portion. When,
A first actuator having a first rotor that rotates on a rotating shaft parallel to the shaft portion by a magnetic force generated by a first coil wound around a part of the first yoke;
A second actuator having a second rotor that rotates on a rotation axis parallel to the shaft portion by a magnetic force generated by a second coil wound around a part of the second yoke;
A main gear fixed to the arm and having a rotation axis coinciding with the central axis of the shaft portion;
A first sub-gear that meshes with the main gear, and whose rotation axis coincides with the rotation axis of the first rotor and rotates in conjunction with the first rotor;
A second sub-gear that meshes with the main gear and whose rotation axis coincides with the rotation axis of the second rotor and rotates in conjunction with the second rotor.

  According to the present invention, the driving force generated by the first actuator is transmitted to the main gear via the first sub gear, and the driving force generated by the second actuator is transmitted to the main gear via the second sub gear. . Therefore, when a large torque is generated in the main gear, the driving force generated in each of the first actuator and the second actuator may be smaller than in the configuration in which the main gear is driven by a single actuator. The total volume of the first actuator and the second actuator can be made smaller than the volume of. Therefore, it is possible to drive the blades with a large driving force while reducing the size.

2 is a front view of a focal plane shutter for a camera according to Embodiment 1. FIG. 2 is a front view of a shutter, an arm, an actuator, a drive gear, and an output gear according to Embodiment 1. FIG. FIG. 3 is a perspective view of a ground plane, an actuator, a drive gear, and an output gear according to the first embodiment. FIG. 3 is an exploded perspective view of a ground plane, an actuator, a drive gear, and an output gear according to the first embodiment. 1 is a configuration diagram of a shutter control device according to Embodiment 1. FIG. It is a figure for demonstrating the control table which the shutter control apparatus which concerns on Embodiment 1 uses. 4 is a flowchart illustrating an example of shutter drive processing according to the first embodiment. 6 is a time chart showing a relationship among a shutter state, a voltage applied to a first coil, and a voltage applied to a second coil in the shutter driving process according to the first embodiment. 6 is an operation explanatory diagram of a focal plane shutter for a camera according to Embodiment 1. FIG. 6 is an operation explanatory diagram of a focal plane shutter for a camera according to Embodiment 1. FIG. 6 is an operation explanatory diagram of a focal plane shutter for a camera according to Embodiment 1. FIG. 5 is a configuration diagram of a shutter control device according to Embodiment 2. FIG. It is a figure for demonstrating the control table which the shutter control apparatus which concerns on Embodiment 2 uses. 6 is a flowchart illustrating an example of a shutter drive process according to the second embodiment. In the shutter driving process according to the second embodiment, the relationship among the shutter state, the applied voltage to the first coil, the applied voltage to the second coil, the torque generated in the first rotor, and the torque generated in the second rotor is shown. It is a time chart which shows. It is a front view of the focal plane shutter for cameras concerning a modification.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
The focal plane shutter system for a camera according to the present embodiment is mounted on a camera such as a digital camera or a still camera. The camera focal plane shutter system includes a camera focal plane shutter and a shutter control device that controls the camera focal plane shutter. As shown in FIG. 1, 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, a first actuator 110, a second actuator 120, and a holder. 220. In the present embodiment, the focal plane shutter 1 is described as a single curtain type.

  The base plate 210 has an opening 211 having a rectangular shape in plan view in a part thereof. Shaft portions 143 and 144 that support the arms 141 and 142 in a turnable manner are provided on the outer peripheral portion of the opening 211 in the base plate 210. Further, a stopper 212 for maintaining the shutter curtain 150 in a set state is disposed on the outer peripheral portion of the opening 211 in the base plate 210. The set state is a state where the shutter curtain 150 covers the opening 211. The stopper 212 restricts the movement of the arm 141 by, for example, electromagnetic force, and thereby maintains the shutter curtain 150 in the set state.

  The shutter curtain 150 includes a plurality of blades. In the present embodiment, the shutter curtain 150 includes four blades 151, 152, 153, and 154 as shown in FIG. The shutter curtain 150 is connected to the arms 141 and 142, and moves up and down in plan view in conjunction with the arm 141 turning around the shaft portion 143 during photographing.

  Specifically, the shutter curtain 150 is in a state of covering a part of the opening 211 as the blades 151, 152, 153, and 154 move from the superimposed state (first state). When the blades 151, 152, 153, and 154 further move from this state, the shutter curtain 150 is in the unfolded state (second state) and the opening 211 is fully closed.

  The overlapping state is a state in which a plurality of blades 151, 152, 153, and 154 overlap each other on the outer periphery of the opening 211 of the base plate 210 in 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 are unfolded to 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 in which everything is covered in plan view. FIG. 1 shows the shutter curtain 150 in the unfolded state.

  A 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. 2, the arm 141 is connected to the blade 151 through the pin 141a, is connected to the blade 152 through the pin 141b, and is connected to the blade 153 through the pin 141c. The arm 142 is connected to the blade 151 via the pin 142a, is connected to the blade 152 via the pin 142b, and is connected to the blade 153 via the pin 142c.

  The first actuator 110 includes a first yoke 112, a first coil 111 wound around a part of the first yoke 112, and a rotating shaft J21 parallel to the shaft portion 143 by a magnetic force generated by the first coil 111. It has the 1st rotor 113 which rotates. Further, as shown in FIG. 3, the conductive lines L11 and L12 derived from the first coil 111 and the conductive lines L21 and L22 derived from the second coil 121 are connected to the shutter control device 3. Here, when a current is supplied from the shutter control device 3 to the first coil 111 via the conductive wires L <b> 11 and L <b> 12, the first yoke 112 is excited by the first coil 111, and magnetic force is applied to the first rotor 113. Make it work. The second actuator 120 has the same configuration as the first actuator 110, and includes a second rotor 123, a second yoke 122, and a second coil 121. When a current is supplied from the shutter control device 3 to the second coil 121 via the conductive wires L21 and L22, the second yoke 122 is excited by the second coil 121 and causes a magnetic force to act on the second rotor 123. The first yoke 112 and the second yoke 122 are made of a magnetic material such as iron. The first coil 111 and the second coil 121 are made of a conductive material such as copper. The first rotor 113 and the second rotor 123 are formed from magnets.

  The drive gear (main gear) 131 is for driving the arm 141, is provided integrally with the arm 141, and the rotation axis J <b> 1 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 FIGS. 2 and 4, the drive gear 131 has an insertion hole 131a through which the shaft portion 143 is inserted. When the drive gear 131 rotates on the rotation shaft J1, the arm 141 is rotated around the shaft portion 143. Turn to.

  The first output gear (first sub gear) 114 is a gear for transmitting the torque generated by the first actuator 110 to the drive gear 131. The first output gear 114 according to the present embodiment is fixed to the first rotor 113 by fitting, and thereby rotates in conjunction with the first rotor 113. The first output gear 114 has teeth provided in an arc shape, and these teeth mesh with the drive gear 131.

  The second output gear (second sub gear) 124 meshes with the drive gear 131, the rotation axis thereof coincides with the rotation axis J <b> 22 of the second rotor 123, and rotates in conjunction with the second rotor 123. The first output gear 114 and the second output gear 124 are fitted to the first rotor 113 and the second rotor 123, respectively.

  According to such a configuration, when the first rotors 113 and 123 rotate, the first output gear 114 rotates about the rotation axis J21 of the first rotor 113, and the second output gear 124 It rotates around the rotor 123. Then, the outputs of the first output gear 114 and the second output gear 124 are transmitted to the drive gear 131. When the drive gear 131 rotates, 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 turns.

  In addition, as shown in FIG. 4, angle deviation suppressing members 116 and 117 for suppressing the deviation of the rotation angle with respect to the drive gear 131 are arranged between the first output gear 114 and the second output gear 124. Yes.

  The holder 220 holds the first actuator 110 and the second actuator 120. The holder 220 is fixed to the base plate 210 with an adhesive or the like. The holder 220 is formed from a synthetic resin or the like. As shown in FIGS. 3 and 4, the holder 220 includes a holder main body 220a and a lid portion 220b.

  The holder main body 220a includes a shaft portion 222 that rotatably supports the first rotor 113 of the first actuator 110, and a shaft portion 223 that rotatably supports the second rotor 123 of the second actuator 120.

  The holder main body 220a has a shaft portion 143 that protrudes on the opposite side of the shaft portions 222 and 223 from which the shaft portions 222 and 223 protrude and supports the drive gear 131 in a rotatable manner. A screw hole 220c is provided on the side of the holder main body 220a facing 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 220b is fixed to the holder main body 220a by screwing a screw 221 inserted through the through hole 220d into the screw hole 220c.

  Next, the configuration of the shutter control device 3 will be described. The shutter control device controls the state of the shutter curtain 150 by supplying a voltage to the first coil 111 and the second coil 121. As shown in FIG. 5, the shutter control device 3 supplies power to the drive circuit 320 that drives the camera focal plane shutter 1, the control circuit 310 that controls the drive circuit 320, and the drive circuit 320 and the control circuit 310. A battery (power source) 300.

  The battery 300 is a power source that supplies a voltage within a range of, for example, a maximum of 3.2 V to a minimum of 2.2 V to the drive circuit 320 and the control circuit 310.

  The drive circuit 320 includes a polarity switching circuit 321 and 322 for individually switching the polarity of the voltage applied to the first coil 111 and the second coil 121, and the voltage applied to the first coil 111 and the second coil 121. Voltage changing circuits 323 and 324 for changing the voltage value.

  The polarity switching circuit 321 switches the polarity of the voltage applied to the first coil 111, and the polarity switching circuit 322 switches the polarity of the voltage applied to the second coil 121. The voltage changing circuit 323 changes the voltage value of the voltage output to the polarity switching circuit 321, and the voltage changing circuit 324 changes the voltage value of the voltage output to the polarity switching circuit 322.

  The polarity switching circuit 321 is a circuit having a bridge configuration including four transistors Tr11, Tr12, Tr13, Tr14. The polarity switching circuit 322 is also a bridge-structured circuit including four transistors Tr21, Tr22, Tr23, Tr24.

  The voltage changing circuit 323 includes a voltage dividing circuit formed by connecting a plurality of (two in FIG. 5) resistors R11 and R12 in series, and a transistor that is connected in parallel to the resistor R11 and bypasses the resistor R11 when in an on state. (Switching element) Tr10. In addition, the voltage changing circuit 324 is connected to the voltage dividing circuit formed by connecting a plurality of (two in FIG. 5) resistors R21 and R22 in series and the resistor R21 in parallel, and bypasses the resistor R21 when in the on state. Transistor (switching element) Tr20.

  Thus, in the shutter control device 3, the voltage changing circuits 323 and 324 have a relatively simple circuit configuration. As a result, the number of components of the drive circuit 320 can be reduced, and there is an advantage that the shutter control device 3 can be easily downsized.

  The control circuit 310 includes a CPU (Central Processing Unit) and a storage unit. The CPU reads out and executes a program stored in the storage unit, whereby the transistors included in the polarity switching circuit 321 and the voltage change circuit 323 are individually provided. To control. The control circuit 310 is connected to an input device (not shown) of a digital camera on which the shutter control device 3 is mounted. The input device includes an operation button. When the operation button 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 constituting the shutter curtain 150. As will be described later, the control circuit 310 performs a series of processes in response to the input of the operation notification signal. In addition, the control circuit 310 includes a timer unit 311 configured from a hardware timer or a software timer.

  The memory of the control circuit 310 stores a control table that defines four operation modes M1, M2, M3, and M4 as shown in the left six columns of the table of FIG. The two columns on the right side of the table of FIG. 6 show operations corresponding to the operation modes M1, M2, M3, and M4. The “forward rotation” shown in the second column from the right in the table of FIG. 6 means that the first rotor 113 of the first actuator 110 or the second rotor 123 of the second actuator 120 in FIG. 1 rotates counterclockwise. The “reverse rotation” shown in the second column from the right in the table of FIG. 6 is a direction in which the first rotor 113 or the second rotor 123 rotates clockwise in FIG.

  As shown in FIG. 6, in the operation modes M1 and M3, the first rotor 113 or the second rotor 123 rotates forward, and in the operation modes M2 and M4, the first rotor 113 or the second rotor 123 is reversed. Rotate. In the operation modes M1 and M2, the applied voltage to the first coil 111 or the second coil 121 is V0. In the operation modes M3 and M4, the applied voltage to the first coil 111 or the second coil 121 is from V0. V11 is also low. Thereby, in the operation modes M1 and M2, the torque generated in the first rotor 113 or the second rotor 123 is larger than in the operation modes M3 and M4.

  Next, shutter drive processing executed by the control circuit 310 according to the present embodiment will be described with reference to FIG. Here, a description will be given assuming that the camera focal plane shutter system is mounted on a digital camera. In this digital camera, when the operation button is pressed, exposure is started by operating the image sensor, and thereafter, a series of operations are performed in which the shutter curtain 150 is closed at a timing when a preset exposure time elapses. The Here, in particular, a shutter drive process for executing the opening / closing operation of the shutter curtain 150 will be described. The shutter driving process is started when a shooting instruction is received from the user, for example, when the shutter button is pressed while the digital camera is powered on.

  First, the control circuit 310 determines whether or not a shooting instruction signal for instructing shooting has been input (step S1). The shooting instruction signal is input to the control circuit 310 after the user presses the operation button of the digital camera. The control circuit 310 maintains the standby state while the imaging instruction signal is not input (step S1: No).

  On the other hand, when the photographing instruction signal is input to the control circuit 310 (step S1: Yes), the control circuit 310 refers to the control table, and the first actuator 110 is in the operation mode M2, and the second actuator 120 is in the operation mode M3. The drive circuit 320 is controlled to operate at (Step S2). At this time, the control circuit 310 operates the timer unit 311 to start timing.

  As shown in FIG. 8, it is assumed that an operation button of the digital camera is pressed at time t0, and a shutter close command signal is input to the control circuit 310 at time t0. At time t0, the voltage −VO is applied to the first coil 111 of the first actuator 110, and the voltage V11 is applied to the second coil 121 of the second actuator 120. In this case, as shown in FIG. 9, reverse rotation torque (see arrow AR11 in FIG. 9) is generated in the first rotor 113, and forward rotation torque (FIG. 9) is generated in the second rotor 123. Middle arrow AR21) occurs.

  When reverse rotation torque is generated in the first rotor 113, a force is generated in the drive gear 131 to rotate in the direction in which the shutter curtain 150 closes (arrow AR31 in FIG. 9). Further, when a forward rotation torque is generated in the second rotor 123, a force is generated in the drive gear 131 that rotates in the direction in which the shutter curtain 150 opens (the direction opposite to the arrow AR31 in FIG. 9).

  Since the absolute value V0 of the voltage applied to the first coil 111 is smaller than the absolute value V11 of the voltage applied to the second coil 121, the magnitude of the reverse rotation torque of the second rotor 123 is It becomes larger than the magnitude of the forward rotation torque of the single rotor 113. Therefore, as shown in FIG. 9, the shutter curtain 150 is maintained in a superimposed state.

  Returning to FIG. 7, the control circuit 310 determines whether or not a preset first waiting time has elapsed after executing the process of step S <b> 2 (step S <b> 3). The control circuit 310 determines the elapse of the first standby time based on the time value of the time measuring unit 311. The first standby time is set to a time longer than the rising time from when a voltage is applied to the first coil 111 or the second coil 121 until the torque is generated in the first rotor 113 or the second rotor 123. .

  The control circuit 310 continues operating the first actuator 110 in the operation mode M2 and the second actuator 120 in the operation mode M3 until the first standby time elapses (step S3: No).

  In step S3, when the first standby time has elapsed, the control circuit 310 determines that the first standby time has elapsed (step S3: Yes). In this case, the control circuit 310 refers to the control table and controls the drive circuit 320 so that both the first actuator 110 and the second actuator 120 operate in the operation mode M1 (step S4).

  As shown in FIG. 8, when the first standby time elapses at time t <b> 2, the voltage + VO is applied to both the first coil 111 and the second coil 121. In this case, as shown in FIG. 10, forward rotation torque (see arrows AR <b> 12 and AR <b> 22 in FIG. 10) is generated in the first rotor 113 and the second rotor 123. In this case, both the first rotor 113 and the second rotor 123 rotate forward, and the drive gear 131 rotates in the direction in which the shutter curtain 150 is fully closed (see arrow AR32 in FIG. 10). As a result, the shutter curtain 150 moves in a direction to fully close the opening of the base plate 210 (arrow AR52 in FIG. 10).

  Returning to FIG. 7, the control circuit 310 determines whether or not a preset second standby time has elapsed after executing the process of step S <b> 4 (step S <b> 5). The control circuit 310 determines the elapse of the second standby time based on the time value of the time measuring unit 311. As shown in FIG. 11, the second waiting time is the time required for the shutter curtain 150 to reach a state of covering about 4/5 of the opening 211 (L2 / L1 in FIG. 11 is about 4/5). Set to The control circuit 310 continues operating both the first actuator 110 and the second actuator 120 in the operation mode M1 until the second standby time has elapsed (step S5: No). As shown in FIG. 8, the shutter curtain 150 approaches the fully closed state with time.

  Returning to FIG. 7, in step S5, when the second standby time has elapsed, the control circuit 310 determines that the second standby time has elapsed (step S5: Yes). In this case, the control circuit 310 refers to the control table and controls the drive circuit 320 so that the first actuator 110 operates in the operation mode M4 and the second actuator 120 operates in the operation mode M1 (step S6). That is, the control circuit 310 switches the second actuator 120 to the operation mode M1 while continuously operating the first actuator 110 in the operation mode M4.

  As shown in FIG. 8, when the second standby time has elapsed at time t3, the voltage −V11 is applied to the first coil 111. In this case, as shown in FIG. 11, reverse rotation torque (see arrow AR13 in FIG. 11) is generated in the first rotor 113, and forward rotation torque (FIG. 11) is generated in the second rotor 123. Middle arrow AR23) occurs. Since the magnitude of the reverse rotation torque generated in the first rotor 113 is smaller than the magnitude of the forward rotation torque generated in the second rotor 123, the drive gear 131 continues normal rotation. However, the drive gear 131 is decelerated by the reverse rotation torque generated in the first rotor 113.

  Returning to FIG. 7, after executing the process of step S <b> 6, the control circuit 310 determines whether or not a preset third standby time has elapsed (step S <b> 7). The control circuit 310 determines the elapse of the third standby time based on the time value of the time measuring unit 311. The third standby time is set to be longer than the time required for the shutter curtain 150 to be in the unfolded state. The control circuit 310 continues operating the first actuator 110 in the operation mode M4 and the second actuator 120 in the operation mode M1 until the third standby time has elapsed (step S7: No). Thus, the shutter curtain 150 is at a lower speed immediately after the shutter curtain 150 starts moving in the fully closing direction, that is, when both the first actuator 110 and the second actuator 120 are operating in the operation mode M1. It moves in the direction to fully close the opening of the main plate 210 (arrow AR53 in FIG. 11). Thereafter, when the movement of the arm 142 is restricted by the stopper 212, the shutter curtain 150 is maintained in a state of covering the opening 211 of the base plate 210 in the unfolded state.

  If it is determined in step S7 that the third standby time has elapsed (step S7: Yes), the control circuit 310 stops the drive circuit 320 (step S8). The control circuit 310 stops the drive circuit 320 by turning off all the transistors constituting the polarity switching circuit 321. As shown in FIG. 8, when it is determined that the shutter curtain 150 is in the unfolded state at time t4, the voltages applied to the first coil 111 and the second coil 121 are set to zero.

  Returning to FIG. 7, after executing the process of step S8, the control circuit 310 determines whether or not a preset fourth waiting time has elapsed (step S9). The control circuit 310 determines the elapse of the fourth standby time based on the time value of the time measuring unit 311. The fourth standby time is set based on, for example, the exposure time of the digital camera. The control circuit 310 maintains the drive circuit 320 in a stopped state until the fourth standby time has elapsed (step S9: No).

  In step S9, when the fourth standby time has elapsed, the control circuit 310 determines that the fourth standby time has elapsed (step S9: Yes). In this case, the control circuit 310 refers to the control table and controls the drive circuit 320 to operate both the first actuator 110 and the second actuator 120 in the operation mode M2 (step S10).

  As illustrated in FIG. 8, if the fourth standby time has elapsed at time t <b> 5, the voltage −VO is applied to both the first coil 111 and the second coil 121. In this case, reverse rotation torque is generated in the first rotor 113 and the second rotor 123. In this case, both the first rotor 113 and the second rotor 123 rotate in the reverse direction, and the drive gear 131 rotates in the direction in which the shutter curtain 150 is fully opened. Thereby, as shown in FIG. 8, the shutter curtain 150 approaches the fully open state with time.

  Returning to FIG. 7, after executing the process of step S <b> 10, the control circuit 310 determines whether or not a preset fifth standby time has elapsed (step S <b> 11). The control circuit 310 determines the elapse of the fifth standby time based on the time value of the time measuring unit 311. The fifth standby time is set to be longer than the time required for the shutter curtain 150 to change from the deployed state to the superimposed state. The control circuit 310 continues operating both the first actuator 110 and the second actuator 120 in the operation mode M2 as long as the fifth standby time has not elapsed (step S11: No).

  If it is determined in step S11 that the fifth standby time has elapsed (step S11: Yes), the control circuit 310 stops the drive circuit 320 (step S12). As shown in FIG. 8, when the fifth standby time has elapsed at time t6, the voltages applied to the first coil 111 and the second coil 121 are set to zero.

  As described above, in the focal plane shutter system for a camera according to the present embodiment, the driving force generated by the first actuator 110 is transmitted to the driving gear 131 via the first output gear 114 and the second actuator 120. Is transmitted to the drive gear 131 via the second output gear 124. Therefore, when a large torque is generated in the drive gear 131, the driving force generated in each of the first actuator 110 and the second actuator 120 may be smaller than the configuration in which the drive gear 131 is driven by a single actuator. Further, the entire volume of the first actuator 110 and the second actuator 120 can be made smaller than the volume of a single actuator. Therefore, it is possible to drive the blades with a large driving force while reducing the size.

  Moreover, in the focal plane shutter system for a camera according to the present embodiment, the size of the first rotor 113 or the second rotor 123 can be reduced, so that the first rotor 113 or the second rotor 123 can be reduced. The amount of inertia can be reduced. Therefore, there is also an advantage that energy transmission efficiency from the first coil 111 and the second coil 121 to the first rotor 113 and the second rotor 123 is improved.

  Furthermore, in the focal plane shutter system for a camera according to the present embodiment, since the first yoke 112 and the second yoke 122 can be made small, the first coil 111 and the second yoke wound around the first yoke 112. The cross-sectional area of the second coil 121 wound around 122 can be reduced. By this. Since the inductance of the first coil 111 and the second coil 121 can be reduced, the power loss in the first coil 111 and the second coil 121 can be reduced.

  In the shutter drive processing according to the present embodiment, it is assumed that the state of the shutter curtain 150 is in the superimposed state immediately before the transition from the superimposed state to the unfolded state (see from time t1 to time t2 in FIG. 8). In this case, the shutter control device 3 causes the first rotor 113 to generate reverse rotation torque, and causes the second rotor 123 to generate forward rotation torque. Here, the magnitude of the reverse rotation torque of the first rotor 113 is larger than the magnitude of the forward rotation torque of the second rotor 123. As a result, while maintaining the shutter curtain 150 in the superimposed state, a voltage having a polarity that causes the second rotor 123 to rotate forward is continuously applied to the second coil 121. Thereby, it is possible to shorten the delay time from immediately after the polarity applied to the first coil 111 changes until the shutter curtain 150 starts moving in the fully closed direction.

  In the shutter driving process according to the present embodiment, reverse rotation torque is generated in the first rotor 113 while the state of the shutter curtain 150 shifts from the superimposed state to the unfolded state (time t3 in FIG. 8). A positive rotation torque is generated in the two-rotor 123. Here, the magnitude of the reverse rotation torque of the first rotor 113 is smaller than the magnitude of the forward rotation torque of the second rotor 123. Accordingly, the drive gear 131 is decelerated by the reverse rotation torque generated in the first rotor 113 while continuing the normal rotation. Therefore, the impact when the arm 142 to which the shutter curtain 150 is connected is regulated by the stopper 212 provided on the main plate 210 can be reduced, and the wear of the arm 142 can be reduced.

(Embodiment 2)
In the shutter control device 3 according to the present embodiment, the first actuator 110 and the second actuator 120 are applied to the first rotor 113 when the same voltage is applied to the first coil 111 and the second coil 121. The point that the generated torque is configured to be larger than the torque generated in the second rotor 123 is different from the first embodiment.

  The number of turns of the first coil 111 is set larger than the number of turns of the second coil 121. As a result, when the same voltage is applied to the first coil 111 and the second coil 121, the torque generated in the first rotor 113 is larger than the torque generated in the second rotor 123.

  As shown in FIG. 12, the shutter control device 2003 according to the present embodiment has a configuration in which the voltage changing circuits 323 and 324 are omitted from the shutter control device 3 according to the first embodiment. Polarity switching circuits 321 and 322 are directly connected between both ends of the battery 300. The control circuit 2310 controls only the polarity switching circuit 321.

  The memory of the control circuit 2310 stores a control table that defines two operation modes as shown in the left five columns of the table of FIG. Note that “forward rotation” and “reverse rotation” shown in the rightmost column of the table of FIG. 13 have the same meaning as in the case of FIG. As shown in FIG. 13, in the operation mode M21, the first rotor 113 or the second rotor 123 rotates in the forward direction, and in the operation mode M22, the first rotor 113 or the second rotor 123 rotates in the reverse direction.

  Next, shutter drive processing executed by the control circuit 2310 according to the present embodiment will be described with reference to FIG. First, the control circuit 2310 determines whether or not a shooting instruction signal has been input (step S201). The control circuit 2310 maintains the standby state unless a shooting instruction signal is input (step S201: No).

  On the other hand, if it is determined that the imaging instruction signal is input to the control circuit 2310 (step S201: Yes), the control circuit 2310 causes the first actuator 110 to operate in the operation mode M22 and the second actuator 120 to operate in the operation mode M21. The drive circuit 2320 is controlled (step S202). At this time, the control circuit 2310 starts the time measurement by operating the time measuring unit 311. As shown in FIG. 15, it is assumed that an operation button of the digital camera is pressed at time t0, and an imaging instruction signal is input to the control circuit 2310 at time t1. In this case, at time t1, the voltage −V12 is applied to the first coil 111 of the first actuator 110, and the voltage V12 is applied to the second coil 121 of the second actuator 120. At this time, torque of a magnitude To11 is generated in the first rotor 113 in the reverse rotation direction, and torque of a magnitude To21 having a magnitude smaller than To11 is given in the forward rotation direction to the second rotor 123. Occur. Since the torque To11 for reverse rotation of the first rotor 113 is larger than the torque To21 for forward rotation of the second rotor 123, the drive gear 131 is urged in the reverse rotation direction. Then, as shown in FIG. 9, the blades 151, 152, 153, and 154 are urged in the direction opposite to the direction in which the shutter curtain 150 is fully closed, and the shutter curtain 150 is maintained in a superimposed state.

  Returning to FIG. 14, the control circuit 2310 determines whether or not a preset first waiting time has elapsed after executing the process of step S202 (step S203). The length of the first waiting time is the same as in the first embodiment. The control circuit 2310 continues to operate the first actuator 110 in the operation mode M22 and the second actuator 120 in the operation mode M21 as long as the first standby time has not elapsed (step S203: No).

  On the other hand, in step S203, when the first standby time has elapsed, the control circuit 2310 determines that the first standby time has elapsed (step S203: Yes). In this case, the control circuit 310 refers to the control table and controls the drive circuit 2320 so that both the first actuator 110 and the second actuator 120 operate in the operation mode M21 (step S204). As shown in FIG. 15, if the first standby time has elapsed at time t <b> 2, the voltage + V <b> 12 is applied to both the first coil 111 and the second coil 121. At this time, a positive rotation torque having a magnitude To11 is generated in the first rotor 113, and a torque in the positive rotation direction having a magnitude To21 is generated in the second rotor 123. Since both the first rotor 113 and the second rotor 123 rotate normally, the drive gear 131 also rotates normally. As a result, as shown in FIG. 10, the shutter curtain 150 moves in a direction to be fully closed with time.

  Returning to FIG. 14, the control circuit 2310 determines whether or not a preset second standby time has elapsed after executing the process of step S204 (step S205). The length of the second waiting time is the same as in the first embodiment. The control circuit 2310 continues to operate both the first actuator 110 and the second actuator 120 in the operation mode M21 as long as the second standby time has not elapsed (step S205: No).

  On the other hand, in step S205, when the second standby time has elapsed, the control circuit 2310 determines that the second standby time has elapsed (step S205: Yes). In this case, the control circuit 2310 refers to the control table and controls the drive circuit 2320 so that the first actuator 110 operates in the operation mode M21 and the second actuator 120 operates in the operation mode M22 (step S206). That is, the control circuit 2310 switches the second actuator 120 to the operation mode M22 while continuously operating the first actuator 110 in the operation mode M21. As illustrated in FIG. 15, when the second standby time has elapsed at time t <b> 3, the voltage −V <b> 12 is applied to the second coil 121. At this time, reverse rotation torque having a magnitude To21 is generated in the second rotor 123. Since the magnitude of the forward rotation torque To11 generated in the first rotor 113 is larger than the magnitude of the reverse rotation torque To21 generated in the second rotor 123, the drive gear 131 continues normal rotation. However, since a force acts in the reverse rotation direction from the second rotor 123 to the drive gear 131, the drive gear 131 decelerates.

  Returning to FIG. 14, the control circuit 2310 determines whether or not a preset third standby time has elapsed after executing the process of step S206 (step S207). The third waiting time is the same as in the first embodiment. The control circuit 2310 continues operating the first actuator 110 in the operation mode M21 and the second actuator 120 in the operation mode M22 as long as the third standby time has not elapsed (step S207: No).

  On the other hand, when it is determined in step S207 that the third standby time has elapsed (step S207: Yes), the control circuit 2310 stops the drive circuit 2320 (step S208). As shown in FIG. 15, when it is determined that the third standby time has elapsed at time t4, the voltages applied to the first coil 111 and the second coil 121 are set to zero.

  Returning to FIG. 14, the control circuit 2310 determines whether or not a preset fourth standby time has elapsed after executing the process of step S208 (step S209). The length of the fourth waiting time is the same as that in the first embodiment. The control circuit 2310 maintains the drive circuit 2320 in a stopped state unless the fourth waiting time has elapsed (step S209: No).

  On the other hand, in step S209, when the fourth standby time has elapsed, the control circuit 2310 determines that the fourth standby time has elapsed (step S209: Yes). In this case, the control circuit 2310 controls the drive circuit 2320 so that both the first actuator 110 and the second actuator 120 operate in the operation mode M22 (step S210). As illustrated in FIG. 15, when the fourth standby time has elapsed at time t5, the voltage −V12 is applied to both the first coil 111 and the second coil 121. At this time, reverse rotation torque of magnitude To11 is generated in the first rotor 113, and reverse rotation torque of magnitude To21 is generated in the second rotor 123. Since both the first rotor 113 and the second rotor 123 rotate in the reverse direction, the drive gear 131 also rotates in the reverse direction. As a result, the shutter curtain 150 moves in a direction in which the shutter curtain 150 is fully opened over time.

  Returning to FIG. 14, the control circuit 2310 determines whether or not a preset fifth standby time has elapsed after performing the process of step S210 (step S211). The length of the fifth waiting time is the same as that in the first embodiment. The control circuit 2310 continues to operate both the first actuator 110 and the second actuator 120 in the operation mode M22 as long as the fifth standby time has not elapsed (step S211: No).

  On the other hand, when it is determined in step S211 that the fifth standby time has elapsed (step S211: Yes), the control circuit 2310 stops the drive circuit 2320 (step S212). As shown in FIG. 15, when the fifth standby time has elapsed at time t6, the voltages applied to the first coil 111 and the second coil 121 are set to zero.

  As described above, the first actuator 110 and the second actuator 120 according to the present embodiment have the first rotor when the same voltage is applied to the first coil 111 and the second coil 121. The torque generated in 113 is configured to be larger than the torque generated in the second rotor 123. Accordingly, the drive circuit 2320 can include only the polarity switching circuit 321 and the control circuit 2310 can control only the polarity switching circuits 321 and 322. Therefore, the structure of the drive circuit 2320 can be simplified. In addition, the control content of the control circuit 2310 can be simplified.

  In the shutter driving process according to the present embodiment, during the transition of the state of the shutter curtain 150 from the superimposed state to the unfolded state (time t3 in FIG. 15), a positive rotation torque is generated in the first rotor 113, and the first A reverse rotation torque is generated in the two-rotor 123. The forward rotation torque of the first rotor 113 is larger than the reverse rotation torque of the second rotor 123. Accordingly, the drive gear 131 is decelerated by the reverse rotation torque generated in the second rotor 123 while continuing the normal rotation. Therefore, the impact when the arms 141 and 142 to which the shutter curtain 150 is connected comes into contact with the stopper 146 provided on the base plate 210 can be reduced, and wear of the arms 142 can be reduced.

(Modification)
As mentioned above, although each embodiment of this invention was described, this invention is not limited to the structure of each above-mentioned embodiment. For example, the camera focal plane shutter may be configured to include two shutter curtains 150. The focal plane shutter according to this modification is a two-curtain focal plane shutter.

  As shown in FIG. 16, the focal plane shutter 3001 for a camera according to the present modification includes the first actuator 110, the second actuator 120, the drive gear 131, the first output gear 114, and the second output described in the first embodiment. Two sets including a gear 124 and a shutter curtain 150 are provided. In addition, stoppers 3212 for restricting the movement of the shutter curtains 150 are disposed at portions corresponding to the two shutter curtains 150 in the outer peripheral portion of the opening 3211 of the base plate 3210. The drive circuit of the shutter control device includes polarity switching circuits 321 and 322 and voltage changing circuits 323 and 324 respectively corresponding to the first coil 111 of the first actuator 110 and the second coil 121 of the second actuator 120 of each set. The polarity switching circuits 321 and 322 and the voltage changing circuits 323 and 324 have the same configuration as that described in Embodiment 1 (see FIG. 5). The control circuit of the shutter control device comprehensively controls the polarity switching circuits 321 and 322 and the voltage changing circuits 323 and 324 of each set.

  In the focal plane shutter 3001 for the camera, for example, the shutter curtain 150 on the −Z direction side in FIG. 16 can be set as a so-called front curtain, and the shutter curtain 150 on the + Z direction side can be set as the rear curtain. In this case, the control circuit first executes the shutter driving process of the first embodiment for the shutter curtain 150 of the front curtain to change the shutter curtain 150 of the front curtain from the fully open state to the fully closed state, and then again to the fully open state. The drive circuit is controlled to After that, when a preset time elapses, the control circuit executes the shutter driving process of the first embodiment for the shutter curtain 150 of the rear curtain, so that the shutter curtain 150 of the rear curtain is changed from the fully open state to the fully closed state. Then, the drive circuit is controlled so as to be fully opened again. For example, when the imaging apparatus is disposed opposite to the opening 211 of the camera focal plane shutter 3001, the imaging apparatus is configured such that the shutter curtain 150 of the rear curtain is fully closed after the shutter curtain 150 of the front curtain is changed from the fully closed state to the fully opened state. Images can be captured during the time until the state is reached.

  In this modification, the first actuator 110 and the second actuator 120 may be configured as described in the second embodiment. In this case, the drive circuit includes only four polarity switching circuits 321 and 322. The control circuit controls the four polarity switching circuits 321 and 322 in an integrated manner.

  In Embodiment 1, when the state of the shutter curtain 150 is in the superimposed state immediately before the transition from the superimposed state to the deployed state (between time t1 and time t2 in FIG. 8), the shutter control device 3 performs the first rotation. Alternatively, a forward rotation torque may be generated in the child 113 and a reverse rotation torque may be generated in the second rotor 123. In this case, the reverse rotation torque of the second rotor 123 may be larger than the forward rotation torque of the first rotor 113.

  In the first embodiment, in the middle of the state of the shutter curtain 150 shifting from the superimposed state to the unfolded state (time t3 in FIG. 8), the shutter control device 3 causes the second rotor 123 to generate reverse rotation torque, The first rotor 113 may generate a forward rotation torque. In this case, the magnitude of the reverse rotation torque of the second rotor 123 may be made smaller than the magnitude of the forward rotation torque of the first rotor 113.

  In the second embodiment, the configuration in which the number of turns of the first coil 111 is larger than the number of turns of the second coil 121 has been described. For example, the diameter of the first coil 111 may be set larger than the diameter of the second coil 121. Alternatively, the cross-sectional area of the portion where the first coil 111 of the first yoke 112 is wound is set to be larger than the cross-sectional area of the portion of the second yoke 122 where the second coil 121 is wound. It may be a configuration. Even in this case, when the same voltage is applied to the first coil 111 and the second coil 121, the torque generated in the first rotor 113 is larger than the torque generated in the second rotor 123.

  In the second embodiment, when the same voltage is applied to the first coil 111 and the second coil 121 by the first actuator 110 and the second actuator 120, the torque generated in the first rotor 113 is increased. The torque may be smaller than the torque generated in the second rotor 123.

  In this configuration, when the state of the shutter curtain 150 is in the superimposed state immediately before the transition from the superimposed state to the deployed state (between time t2 and time t3 in FIG. 15), reverse rotation torque is applied to the second rotor 123. May be generated to cause the first rotor 113 to generate a forward rotation torque. In this case, the magnitude of the reverse rotation torque of the second rotor 123 is larger than the magnitude of the forward rotation torque of the first rotor 113. Accordingly, the shutter curtain 150 is maintained in a superimposed state.

  Further, in this configuration, while the state of the shutter curtain 150 is changing from the superimposed state to the unfolded state (time t3 in FIG. 15), the first rotor 113 is generated while generating the positive rotation torque in the second rotor 123. Alternatively, reverse torque may be generated. In this case, the magnitude of the forward rotation torque of the second rotor 123 is larger than the magnitude of the reverse rotation torque of the first rotor 113. Accordingly, the drive gear 131 continues to rotate forward. However, since a force acts in the reverse rotation direction from the first rotor 113 to the drive gear 131, the drive gear 131 decelerates.

  In the second embodiment, when the same voltage is applied to the first coil 111 and the second coil 121, the torque generated in the first rotor 113 is compared with the torque generated in the second rotor 123. A large example has been described. For example, when the same current is supplied to the first coil 111 and the second coil 121, the torque generated in the first rotor 113 is compared with the torque generated in the second rotor 123. The structure which becomes large may be sufficient. In this case, for example, the first yoke 112 and the second yoke 122 may be formed of materials having different magnetic permeability.

  In each of the above-described embodiments, when the state of the shutter curtain 150 is in the superimposed state immediately before the transition from the superimposed state to the deployed state, reverse rotation torque is generated in the first rotor 113 and the second rotor 123 is generated. The example in which the second torque of the forward rotation is generated has been described. Here, the rotation direction when the state of the shutter curtain 150 shifts from the superimposed state to the unfolded state is defined as the main rotation direction. For example, the rotation direction when the state of the shutter curtain 150 transitions from the unfolded state to the superimposed state is the main rotation direction, and the state of the shutter curtain 150 is the unfolded state immediately before the transition from the unfolded state to the superimposed state. In some cases, reverse rotation torque may be generated in the first rotor 113 and forward rotation torque may be generated in the second rotor 123. Here, the magnitude of the torque generated in the first rotor 113 is set larger than the magnitude of the torque generated in the second rotor 123. In this case, the shutter curtain 150 is maintained in the unfolded state.

  In the first embodiment, reverse rotation torque is generated in the first rotor 113 and forward rotation torque is generated in the second rotor 123 in the middle of the state of the shutter curtain 150 shifting from the superimposed state to the deployed state. An example was described. Here, the rotation direction when the state of the shutter curtain 150 shifts from the superimposed state to the unfolded state is defined as the main rotation direction. Not limited to this, for example, the rotation direction when the state of the shutter curtain 150 shifts from the unfolded state to the superimposed state is set as the main rotation direction, and the first state in the middle of the state of the shutter curtain 150 shifting from the unfolded state to the superimposed state. The rotor 113 may generate reverse rotation torque, and the second rotor 123 may generate forward rotation torque. Here, the magnitude of the torque generated in the first rotor 113 is set smaller than the magnitude of the torque generated in the second rotor 123. In this case, when the shutter curtain 150 approaches the superimposed state, a force is applied in the reverse rotation direction from the second rotor 123 to the drive gear 131, so that the drive gear 131 is decelerated. As a result, the shutter curtain 150 moves in the direction to fully open the opening of the base plate 210 at a lower speed than immediately after the shutter curtain 150 starts moving in the fully open direction.

  In the second embodiment described above, forward rotation torque is generated in the first rotor 113 and reverse rotation torque is applied to the second rotor 123 while the state of the shutter curtain 150 shifts from the superimposed state to the deployed state. The example to generate was demonstrated. Here, the rotation direction when the state of the shutter curtain 150 shifts from the superimposed state to the unfolded state is defined as the main rotation direction. Not limited to this, for example, the rotation direction when the state of the shutter curtain 150 shifts from the unfolded state to the superimposed state is set as the main rotation direction, and the first state in the middle of the state of the shutter curtain 150 shifting from the unfolded state to the superimposed state. The rotor 113 may generate forward rotation torque, and the second rotor 123 may generate reverse rotation torque. Here, the magnitude of the torque generated in the first rotor 113 is set larger than the magnitude of the torque generated in the second rotor 123. In this case, when the shutter curtain 150 approaches the superimposed state, a force is applied in the reverse rotation direction from the second rotor 123 to the drive gear 131, so that the drive gear 131 is decelerated. As a result, the shutter curtain 150 moves in the direction of fully opening the opening of the base plate 210 at a lower speed than immediately after the shutter curtain 150 starts moving in the direction of fully opening.

  In the process of step S7 during the shutter drive process according to the first embodiment and the process of step S207 during the shutter drive process according to the second embodiment, the control circuit 310 deploys the shutter curtain 150 after the third standby time has elapsed. The example which determines with a state was demonstrated. For example, a sensor (not shown) for detecting that the shutter curtain 150 is in the unfolded state is disposed on the base plate 210, for example, and the control circuit 310 is based on a signal from the sensor. It may be configured to determine whether or not has been expanded.

  In each of the above-described embodiments, the example in which the second standby time is set to the time required for the shutter curtain 150 to be in a state of covering about 4/5 of the opening 211 from the superimposed state has been described. The ratio L2 / L1 (see FIG. 11) of the portion covered by the shutter curtain 150 in the opening 211 may be other ratios smaller than 1. For example. L2 / L1 may be set to about 2/3 or about 5/6.

  In each of the above-described embodiments, 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 constituting the shutter curtain is not limited to four. For example, the number may be less than four or more than four.

  In each of the above-described embodiments, an example in which one shutter curtain 150 functions as a rear curtain has been described. For example, one shutter curtain 150 is driven as a front curtain and then driven as a rear curtain. Also good.

  In the digital camera according to each of the above-described embodiments, when the operation button is pressed while the shutter curtain 150 is fully open (superimposed state), the shutter curtain 150 is fully closed (deployed state), and then the shutter is again opened. The example in which the curtain 150 is fully opened has been described. For example, the shutter curtain 150 may be fully opened when the shutter curtain 150 is fully closed and the operation button is pressed, 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: shutter control device, 110: first actuator, 111: first coil, 112: first yoke, 113: first rotor, 114: first output gear (first sub gear) ), 120: second actuator, 121: second coil, 122: second yoke, 123: second rotor, 124: second output gear (second sub gear), 131: drive gear (main gear), 131a : Insertion hole, 141, 142: arm, 141a, 141b, 141c, 142a, 142b, 142c: pin, 143, 144, 222, 223: shaft part, 150: shutter curtain, 151, 152, 153, 154: blade, 210: ground plate, 220: holder, 221: screw, 300: battery (power source), 310: control circuit, 320: drive circuit, 321, 322: polarity cut Circuit, 323, 324: voltage changing circuit, J1, J21, J22: rotating shaft, R11, R12, R21, R22: resistor, Tr10, Tr11, Tr12, Tr13, Tr14, Tr20, Tr21, Tr22, Tr23, Tr24: transistor (Switching element)

Claims (8)

A main plate provided with a shaft portion having an opening and rotatably supporting an arm on an outer peripheral portion of the opening;
A shutter curtain connected to the arm and capable of taking a first state retracted to an outer peripheral portion of the opening of the base plate and a second state covering the opening of the base plate by turning the arm around the shaft portion. When,
A first actuator having a first rotor that rotates on a rotating shaft parallel to the shaft portion by a magnetic force generated by a first coil wound around a part of the first yoke;
A second actuator having a second rotor that rotates on a rotation axis parallel to the shaft portion by a magnetic force generated by a second coil wound around a part of the second yoke;
A main gear fixed to the arm and having a rotation axis coinciding with the central axis of the shaft portion;
A first sub-gear that meshes with the main gear, and whose rotation axis coincides with the rotation axis of the first rotor and rotates in conjunction with the first rotor;
A focal plane shutter for a camera having a second sub gear that meshes with the main gear and has a rotation axis that coincides with the rotation axis of the second rotor and rotates in conjunction with the second rotor;
A shutter control device that controls the operation of the shutter curtain by supplying voltage or current to the first coil and the second coil,
Focal plane shutter system for cameras. The shutter control device includes:
Regarding the first rotor, the second rotor, the main gear, the first sub gear, and the second sub gear, the state of the shutter curtain is one of the first state and the second state. The state of the shutter curtain is changed from the one state to the other state when the rotation direction at the time of transition from the state to the other state is the main rotation direction and the rotation direction opposite to the main rotation direction is the reverse rotation direction. When the first rotor is in the one state immediately before shifting to the first rotor, the first rotor generates the first reverse rotation torque, the second rotor generates the second rotation forward torque,
The magnitude of the first torque is greater than the magnitude of the second torque;
The focal plane shutter system for a camera according to claim 1. The shutter control device includes:
Regarding the first rotor, the second rotor, the main gear, the first sub gear, and the second sub gear, the state of the shutter curtain is one of the first state and the second state. The state of the shutter curtain is changed from the one state to the other state when the rotation direction at the time of transition from the state to the other state is the main rotation direction and the rotation direction opposite to the main rotation direction is the reverse rotation direction. In the middle of shifting to, the third rotor generates the third torque of the reverse rotation, the second rotor generates the fourth torque of the forward rotation,
The magnitude of the third torque is smaller than the magnitude of the fourth torque;
The focal plane shutter system for a camera according to claim 1 or 2. The shutter control device includes:
A driving circuit for driving the focal plane shutter for the camera;
A control circuit for controlling the drive circuit;
A power supply for supplying power to the drive circuit and the control circuit,
The drive circuit is
A polarity switching circuit for individually switching the polarity of the voltage supplied to the first coil and the second coil;
A voltage changing circuit for changing the magnitude of the voltage supplied to the first coil and the second coil,
The change circuit includes:
A voltage dividing circuit formed by connecting a plurality of resistors in series;
A switching element that is connected in parallel to a part of the plurality of resistors and bypasses a part of the plurality of resistors in an ON state.
The focal plane shutter system for a camera according to claim 2 or 3. In the first actuator and the second actuator, when the same voltage or current is supplied to the first coil and the second coil, the torque generated in the first rotor is the second actuator. Configured to be larger than the torque generated in the rotor,
The focal plane shutter system for a camera according to claim 1 or 2. The shutter control device includes:
Regarding the first rotor, the second rotor, the main gear, the first sub gear, and the second sub gear, the state of the shutter curtain is one of the first state and the second state. Assuming that the rotation direction at the time of transition from the state to the other state is the main rotation direction, and the rotation direction opposite to the main rotation direction is the reverse rotation direction, the state of the shutter curtain changes from the one state to the other state. During the transition, the first rotor is caused to generate the forward rotation of the fifth torque, the second rotor is caused to generate the reverse rotation of the sixth torque,
The magnitude of the fifth torque is greater than the magnitude of the sixth torque;
The focal plane shutter system for a camera according to claim 5. A focal plane shutter system for a camera according to any one of claims 1 to 6, comprising:
camera. A main plate provided with a shaft portion having an opening and rotatably supporting an arm on an outer peripheral portion of the opening;
A shutter curtain connected to the arm and capable of taking a first state retracted to an outer peripheral portion of the opening of the base plate and a second state covering the opening of the base plate by turning the arm around the shaft portion. When,
A first actuator having a first rotor that rotates on a rotating shaft parallel to the shaft portion by a magnetic force generated by a first coil wound around a part of the first yoke;
A second actuator having a second rotor that rotates on a rotation axis parallel to the shaft portion by a magnetic force generated by a second coil wound around a part of the second yoke;
A main gear fixed to the arm and having a rotation axis coinciding with the central axis of the shaft portion;
A first sub-gear that meshes with the main gear, and whose rotation axis coincides with the rotation axis of the first rotor and rotates in conjunction with the first rotor;
A second sub-gear that meshes with the main gear, and whose rotation axis coincides with the rotation axis of the second rotor and rotates in conjunction with the second rotor.
Focal plane shutter for camera.

Images