JP7362288B2 - Shutter device and imaging device equipped with the same - Google Patents

Description

The present invention relates to a shutter device and an imaging device equipped with the same.

2. Description of the Related Art A focal plane shutter for a camera is known in which a slit formed by two groups of blades attached to a shutter base plate continuously exposes an imaging surface. Furthermore, two drive members are attached to the shutter base plate, each of which is driven by a biasing member to operate each blade group. Furthermore, a motor that drives a cam gear that charges the drive member to a standby position against the urging force of the urging member is attached to the shutter base plate. In a motor, the angle of over-rotation (hereinafter referred to as "overrun") from when the power is turned off until it stops varies depending on the applied voltage and the usage environment. Therefore, a sufficient motor free running section is provided at the cam top of the cam gear so that an overcharged state is ensured even when the motor overruns the most.

Patent Document 1 discloses a shutter device that shortens the release time lag by making the slope area of the cam part that contacts the first drive member smaller than the slope area of the cam part that contacts the rear drive member.

Patent No. 5414463

However, in the shutter device of Patent Document 1, it is necessary to provide a cam area dedicated to live view, in which the front drive member is in a state of completion of travel and the rear drive member is held by the cam top, and the drive member is not charged. The cam area for this purpose is reduced. As a result, current consumption when charging the drive member increases.

In addition, if the slope area is reduced in order to increase the cam area for charging the drive member, the shock applied to the electromagnet will be greater when transitioning to the set release phase before driving, making it easier for the drive member to come unattached. turn into.

SUMMARY OF THE INVENTION An object of the present invention is to provide a shutter device that can suppress current consumption when charging a drive member, and an imaging device equipped with the shutter device.

A shutter device as one aspect of the present invention includes a base plate provided with an opening through which light passes, a first drive member that drives a first blade group, a second drive member that drives a second blade group, and a second drive member that drives a second blade group. A first biasing member that biases the first drive member so that the first blade group moves from a closed state in which the opening is closed to an open state in which the opening is opened, and a second blade group moves from the open state to the closed state. A shutter device comprising: a second biasing member that biases a second drive member; and a cam member that is attached to a rotation shaft provided on a base plate and is rotatable about the rotation shaft by a drive means. , the rotation angle of the cam member relative to the reference position when the shutter device is in the first state in which the first and second driving members are held by the cam member with the first and second biasing members charged. The range is the cam member when the shutter device is in the second state in which the first blade group is in the open state, the second biasing member is charged, and the second driving member is held by the cam member. It is characterized by being the same as the range of rotation angles with respect to the reference position .

According to the present invention, it is possible to provide a shutter device that can suppress current consumption when charging a drive member, and an imaging device equipped with the shutter device.

FIG. 1 is a block diagram of an imaging device according to an embodiment of the present invention. 1 is an exploded perspective view of the focal plane shutter of Example 1. FIG. FIG. 3 is a perspective view of a drive lever of the focal plane shutter in Example 1. FIG. 3 is a diagram showing a cam gear of the focal plane shutter of Example 1. FIG. FIG. 3 is a perspective view of the upper base plate of the focal plane shutter of Example 1. FIG. FIG. 2 is an exploded perspective view of the motor unit of the focal plane shutter of Example 1. FIG. 5 is a time chart showing the operation of each component of the focal plane shutter of Example 1. FIG. FIG. 3 is a diagram showing a pre-release standby state of the focal plane shutter of Example 1; 5 is a diagram showing a set release state of the focal plane shutter of Example 1. FIG. FIG. 6 is a diagram showing a state in which the rear blade group of the focal plane shutter according to the first embodiment has completed traveling. FIG. 3 is a diagram showing a charging start state of the first drive lever of the focal plane shutter according to the first embodiment. FIG. 3 is a diagram showing a charging start state of the rear drive lever of the focal plane shutter in Example 1; 5 is a diagram showing an overcharge state of each blade group of the focal plane shutter of Example 1. FIG. FIG. 3 is a diagram showing a state in which each blade group of the focal plane shutter of Example 1 starts to be released. FIG. 3 is a diagram showing a set release state of each blade group of the focal plane shutter of Example 1. FIG. 5 is a diagram illustrating a state in which the rear curtain setting operation of the focal plane shutter according to the first embodiment is started; FIG. FIG. 3 is a diagram showing the state of the focal plane shutter of Example 1 after the rear curtain is set. FIG. 3 is an exploded perspective view of a focal plane shutter according to a second embodiment. 7 is a time chart showing the operation of each component of the focal plane shutter of Example 2. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same reference numerals are given to the same members, and duplicate explanations will be omitted.

FIG. 1 is a block diagram of an imaging device 200 according to an embodiment of the present invention. The imaging device 200 includes an imaging device main body having an imaging device 203, and an imaging lens (interchangeable lens, lens device, imaging optical system) 201 that is detachable from the imaging device main body. In the imaging device 200, it is possible to select a normal exposure method using leading and trailing blades of a focal plane shutter, and an electronic front curtain method using reset scanning (electronic front curtain scanning) and a trailing blade. Note that in this embodiment, the imaging lens 201 is removable from the imaging device main body, but may be configured integrally with the imaging device main body.

Subject light from the imaging lens 201 is directed toward the imaging device 203. The imaging lens 201 may have an aperture. The imaging device 203 is configured with a CMOS image sensor or the like, and photoelectrically converts a subject image (optical image) formed by the imaging lens 201. A focal plane shutter (shutter device) 202 is arranged on the subject side with respect to the image sensor 203 and controls the amount of exposure to the image sensor 203. A CPU (control means) 204 controls and calculates a shutter drive circuit 205, a vertical drive modulation circuit (scanning means) 208, a signal processing circuit 209, and a lens control means 215. The CPU 204 controls the operation of the focal plane shutter 202 (start timing of blade group travel and drive of the motor) via the shutter drive circuit 205.

The first switch (SW1) 210 is a switch for starting imaging preparation, and the second switch (SW2) 211 is a switch for starting imaging. The first switch 210 and the second switch 211 are configured as two-stage switches, and the first switch 210 is turned on at the first stroke, and the second switch 211 is turned on at the second stroke.

The lens control unit 215 controls photographing condition information (information regarding the state of the lens device, i.e., information regarding the state of the lens device), such as the focal length of the imaging lens 201, the aperture diameter (aperture value), the exit pupil diameter, and the distance between the exit pupil and the image sensor 203. information) to the CPU 204. Further, the lens control unit 215 controls the operation (driving) of the imaging lens 201 (including the aperture) in accordance with instructions from the CPU 204.

The CPU 204 supplies a scanning clock (horizontal drive pulse) and predetermined control pulses to the image sensor 203 via the pulse generation circuit 207 . Of the scanning clocks generated by the pulse generation circuit 207 , the clock for vertical scanning is modulated to a predetermined clock frequency by the vertical drive modulation circuit 208 and input to the image sensor 203 . The vertical drive modulation circuit 208 is a scanning means as an electronic front curtain, and based on a command from the CPU 204, performs a reset scan as an electronic front curtain, that is, a scan pattern of a scan in which charge accumulation is started for each pixel of the image sensor 203. (scan curve). Further, the vertical drive modulation circuit 208 sequentially performs reset scanning from the top to the bottom or from the bottom to the top based on instructions from the CPU 204.

The pulse generation circuit 207 also outputs a clock signal to the signal processing circuit 209. The signal processing circuit 209 generates image data by performing predetermined processing (color processing, gamma correction, etc.) on the signal read out from the image sensor 203. The recording medium 212 records image data generated by the signal processing circuit 209. The display unit 213 is configured with a liquid crystal display (LCD) or the like, and displays images, various menu screens, and the like. A RAM (Random Access Memory) 214 is a storage means that is connected to the signal processing circuit 209 and temporarily stores image data and the like.

The configuration of the focal plane shutter 202 of this embodiment will be described with reference to FIGS. 2 to 6.

FIG. 2 is an exploded perspective view of the focal plane shutter 202. FIG. 2A is an exploded perspective view of the drive lever side of the focal plane shutter 202 viewed from the subject side, and FIG. 2B is an exploded perspective view of the blade chamber side viewed from the photographer side.

FIG. 3 is a perspective view of the front drive lever (first drive member) 4 and the rear drive lever (second drive member) 5. FIG. 3(a) is a perspective view of the first drive lever 4. FIG. FIG. 3(b) is a top view of the first drive lever 4. FIG. 3(c) is a cross-sectional view of a portion of the forward drive lever 4 used to attract the forward electromagnet 22a. FIG. 3(d) is a perspective view of the rear drive lever 5. FIG. 3(e) is a top view of the rear drive lever 5. FIG. 3(f) is a cross-sectional view of a portion of the rear drive lever 5 used to attract the rear electromagnet 22b.

FIG. 4 is a diagram showing the cam gear (cam member) 13. FIG. 4(a) is a diagram of the cam gear 13 viewed from above. FIG. 4(b) is a side view of the cam gear 13. FIG. 4(c) is a diagram of the cam gear 13 viewed from the bottom.

FIG. 5 is a perspective view of the upper base plate 21. FIG. 5(a) is a diagram of the upper base plate 21 viewed from the subject side. FIG. 5(b) is a diagram of the upper base plate 21 viewed from the photographer's side.

FIG. 6 is an exploded perspective view of the motor unit.

The shutter base plate 1 is made of resin, and has an opening 1a in the center. The shutter base plate 1 has a first drive lever shaft 1b, a second drive lever shaft 1c, and a cam gear shaft 1d. Further, the shutter base plate 1 has a front main arm axis 1e, a front sub-arm axis 1f, a rear main arm axis 1g, and a rear sub-arm axis 1h.

A partition plate 2 and a cover plate 3 are attached to the shutter base plate 1 on the photographer's side. The opening 2a of the partition plate 2 and the opening 3a of the cover plate 3 have a similar shape to the opening 1a of the shutter base plate 1, and by overlapping these three openings, a rectangular exposure opening (shutter opening) is formed. and limits the light flux passing through the focal plane shutter 202.

A blade chamber in which a group of blades is arranged is formed between the shutter base plate 1 and the partition plate 2, and between the partition plate 2 and the cover plate 3.

The leading blade group 42 closes the shutter opening before exposure. The leading blade group 42 has a main arm 42a and a sub-arm 42b. The main arm 42a is rotatably attached to the first main arm shaft 1e, and the sub-arm 42b is rotatably attached to the first sub-arm shaft 1f.

Further, the leading blade group 42 includes a first blade 42c, a second blade 42d, a third blade 42e, and a fourth blade 42f. The first blade 42c forms a slit. Each blade is rotatably supported by a main arm 42a and a sub-arm 42b by a pin 42g, forming a parallel link.

The main arm 42a is provided with a hole 42h for engaging with the blade actuation pin 4a of the forward drive lever 4. A front rattling spring 44 is applied to the sub-arm 42b, which biases it counterclockwise in FIG. 2(b) so that the blades overlap.

The rear blade group 43 closes the shutter opening after exposure. The rear blade group 43 has a main arm 43a and a sub-arm 43b. The main arm 43a is rotatably attached to the rear main arm shaft 1g, and the sub arm 43b is rotatably attached to the rear sub arm shaft 1h.

Further, the rear blade group 43 includes a first blade 43c, a second blade 43d, a third blade 43e, and a fourth blade 43f. The first blade 43c forms a slit. Each blade is rotatably supported by a main arm 43a and a sub-arm 43b by a pin 43g, forming a parallel link.

The main arm 43a is provided with a hole 43h for engaging with the blade actuation pin 5a of the rear drive lever 5. A rear rattling spring 45 is applied to the sub-arm 43b and biases it counterclockwise in FIG. 2(b) so that the blades are expanded.

Further, a spacer 41 is attached to the tip of each blade of the leading blade group 42 and the trailing blade group 43 to suppress movement of each blade in the optical axis direction.

The movable end of the forward drive spring (first biasing member) 6 is hung on the forward drive lever 4, and the fixed end is hooked on the adjuster 10. The front drive spring 6 biases the front drive lever 4 so that the front blade group 42 moves from a deployed state (closed state) in which the shutter opening is closed to a superimposed state (open state, travel complete state) in which the shutter opening is opened. do. The movable end of the rear drive spring (second biasing member) 7 is hung on the rear drive lever 5, and the fixed end is hooked on the ratchet 11. The rear drive spring 7 biases the rear drive lever 5 so that the rear blade group 43 moves from a superimposed state (open state) in which the shutter opening is opened to an expanded state (closed state, travel completion state) in which the shutter opening is closed. do.

By rotating the adjuster 10 with the worm 12, the biasing force of the first drive spring 6 can be adjusted. By adjusting the biasing force of the leading drive spring 6, the traveling speed of the leading blade group 42 can be set. The worm stopper 24 holds the worm 12 so that it does not rotate after the adjuster 10 has been rotated.

The ratchet 11 is arranged so that its central axis is coaxial with the rear drive lever shaft 1c. The ratchet 11 is fixed by the ratchet teeth 11a engaging with the ratchet pawls 21a of the upper base plate 21. Furthermore, the biasing force of the rear drive spring 7 can be adjusted by rotating the ratchet 11 and changing the position of the ratchet teeth 11a. By adjusting the urging force of the rear drive spring 7, the traveling speed of the rear blade group 43 can be set.

A front electromagnet 22a, a rear electromagnet 22b, and a flexible substrate (not shown) are fixed to the upper plate 21. A terminal of each electromagnet is connected to a shutter drive circuit 205 via a flexible board (not shown). The magnet cover 23 is fixed to the top plate 21 so as to cover each electromagnet, and protects the attraction portion of each electromagnet and the attraction surface of the armature of each drive lever from external dust.

The motor (driving means) 18 is fastened to the motor base plate 19 with screws 26 . The motor base plate 19 is fastened to the shutter base plate 1 with screws. The first reduction gear 14, the second reduction gear 15, and the third reduction gear 16 are rotatably attached to shafts 19a, 19b, and 19c provided on the motor base plate 19, respectively. Pinion gear 17 is attached to motor 18. The gear cover 20 is fastened to the motor base plate 19 with screws. The rotational force of the motor 18 is transmitted to the pinion gear 17 , the first reduction gear 14 , the second reduction gear 15 , the third reduction gear 16 , and the cam gear 13 in this order.

The forward drive lever 4 includes a blade actuation pin 4a, a roller shaft 4b, an armature shaft 4c, an armature 4d, an armature guide portion 4e, an armature rubber 4f, an armature spring 4g, a PI light shielding portion 4h, a roller (cam follower) 4i, and a slit washer 4j. have The blade operating pin 4a collides with a buffer member 30 made of rubber or the like when the leading blade group 42 completes traveling. The armature shaft 4c is crimped to the armature 4d. The armature guide portion 4e restricts the movement of the armature 4d and assists in adsorption to the forward electromagnet 22a. The PI light shielding section 4h detects the position of the leading drive lever 4 or the leading blade group 42 by switching the brightness and darkness of a PI (photo interrupter) (not shown) fixed to the upper base plate 21. The roller 4i is rotatably attached to a roller shaft 4b, and charges the front drive spring 6 by being pushed by a front cam portion 13a of a cam gear 13, which will be described later. The slit washer 4j is attached to prevent the roller 4i from falling off the roller shaft 4b.

The rear drive lever 5 includes a blade operating pin 5a, a roller shaft 5b, an armature shaft 5c, an armature 5d, an armature guide portion 5e, an armature rubber 5f, an armature spring 5g, a PI light shielding portion 5h, a roller (cam follower) 5i, and a slit washer 5j. have The blade operating pin 5a collides with the buffer member 30 when the rear blade group 43 completes running. The armature shaft 5c is crimped to the armature 5d. The armature guide portion 5e restricts the movement of the armature 5d and assists in adsorption to the rear electromagnet 22b. The PI light shielding section 5h detects the position of the rear drive lever 5 or the rear blade group 43 by switching the brightness and darkness of a PI (photo interrupter), not shown, fixed to the upper base plate 21. The roller 5i is rotatably attached to a roller shaft 5b, and charges the rear drive spring 7 by being pushed by a rear cam portion 13b of a cam gear 13, which will be described later. The slit washer 5j is attached to prevent the roller 5i from falling off the roller shaft 5b.

The front cam portion 13a and the rear cam portion 13b are each formed as a pair at symmetrical positions with respect to the rotation center of the cam gear 13.

The front cam portion 13a has a charging area A1 that charges the front drive spring 6 to a charging completion position (cam top position) via the roller 4i. The front cam portion 13a is made concentrically with the rotation center of the cam gear 13, and has a cam top region B1 that can hold the front drive spring 6 at the charging completion position, and a cam top region B1 that can hold the front drive spring 6 from the charging completion position to the set release position. It has a cam slope area C1 for making the transition.

The front cam portion 13a has a notch portion 13d. The cutout portion 13d is a space into which the roller 4i enters in a live view state, which will be described later. By providing the cutout portion 13d, a longer live view phase can be ensured. The cutout portion 13d has a cutout end portion 13e that faces the roller 4i when transitioning to the live view state.

The rear cam portion 13b has a charging area A2 that charges the rear drive spring 7 to a charging completion position (cam top position) via the roller 5i. The rear cam part 13b is made concentrically with the rotation center of the cam gear 13, and has a cam top area B2 that can hold the rear drive spring 7 at the charging completion position, and a cam top area B2 that can hold the rear drive spring 7 from the charging completion position to the set release position. It has a cam slope area C2 for making the transition.

By meshing with the third reduction gear 16, the gear portion 13c rotates the motor 18 in the normal rotation direction (first direction) or in the reverse rotation direction ( second direction).

Further, a phase contact piece 25 is attached to the cam gear 13 to detect the rotational phase of the cam gear 13 by contacting a phase pattern portion of a flexible substrate (not shown) attached to the upper base plate 21.

The operation of each component of the focal plane shutter 202 will be described below with reference to FIGS. 7 to 17.

FIG. 7 is a time chart showing the operation of each component during live view shooting. 8 to 17 show the states of the focal plane shutter 202. FIG.
(1) Pre-release standby state At timing 301, the focal plane shutter 202 is in a pre-release standby state as shown in FIG. The leading blade group 42 has completed its running, and the roller 4i has entered the notch 13d. The roller 5i contacts the cam surface of the cam top region B2, and the rear drive lever 5 is held by the cam gear 13. That is, the shutter aperture is open and the imaging device 200 is in a live view state. In the state shown in FIG. 8, in order to ensure that the armature 5d and the rear electromagnet 22b are attracted to each other, the rear drive lever 5 is rotated more than the position where the rear electromagnet 22b attracts the rear drive lever 5. Therefore, the state shown in FIG. 8 is also called an overcharge state. This play is absorbed by creating a gap between the armature rubber 5f and the rear drive lever 5.
(2) Set release During the period from timing 302 to timing 304, set release is performed. During this period, the forward drive lever 4 is in a traveling completed state, and the motor 18 is not energized. At timing 302, when the CPU 204 receives a release signal, energization of the motor 18 in the forward rotation direction is started, and the cam gear 13 starts turning right from the state shown in FIG. Furthermore, energization of the rear electromagnet 22b is started. At timing 303, the roller 5i comes into contact with the cam surface of the cam slope area C2. The rear drive lever 5 transitions from the overcharge state to the set release state. The rear cam portion 13b reaches a position where it does not come into contact with the roller 5i and stops. The focal plane shutter 202 enters a released state in which the overcharge state is released. As a result, the rear drive lever 5 becomes movable (driveable) by the rear drive spring 7, but the rear electromagnet 22b is energized and the armature 5d and the rear electromagnet 22b are attracted to each other. ,Stop. That is, the gap between the armature rubber 5f and the rear drive lever 5 caused by overcharging is eliminated, the armature rubber 5f is further compressed, and the rear drive lever 5 is held in a state in which the load of the rear drive spring 7 is balanced. After the phase contact piece 25 detects that the rear cam portion 13b has retreated from the drive locus of the rear drive lever 5 and the cam gear 13 has rotated to the right to a phase where the rear drive lever 5 can travel, at timing 304, Motor 18 stops. At this time, the focal plane shutter 202 is in the unset state as shown in FIG.
(3) Photography Photography is performed during the period from timing 304 to timing 307. At timing 304, after a predetermined period of time has passed after the motor 18 stops, the image sensor 203 starts electronic front curtain scanning. At timing 305, the power supply to the rear electromagnet 22b is terminated. The exposure time of the image sensor 203 is determined by the electronic front curtain imitating the slit of the first blade 42c and the timing of de-energizing the rear electromagnet 22b. The rear drive lever 5 is biased by the rear drive spring 7 and starts running from the state shown in FIG. At timing 306, the blade operating pin 5a collides with the buffer member 30, and the trailing blade group 43 completes its travel. At this time, the focal plane shutter 202 is in a state where the rear blade group 43 in FIG. 10 has completed running. Thereafter, a predetermined period of time (in this embodiment, the period from timing 306 to timing 307) must elapse after the trailing blade group 43 completes its travel until the swinging of each blade becomes stable.
(4) Set operation During the period from timing 307 to timing 310, the front drive lever 4 and the rear drive lever 5 are moved from the traveling completion state to the overcharged state (charged state) against the urging force of the front drive spring 6 and the rear drive spring 7. A set operation is performed to set the completed state. At timing 307, energization of the motor 18 in the forward rotation direction is started, and the cam gear 13 starts turning right from the state shown in FIG. At timing 308, the first drive lever 4 reaches the charged position. The focal plane shutter 202 is in the charging start state of the first drive lever 4 in FIG. When the cam gear 13 further rotates to the right, the roller 4i comes into contact with the cam surface of the charging area A1, and charging of the first drive lever 4 is started. At timing 309, the focal plane shutter 202 enters the charging start state of the rear drive lever 5 shown in FIG. As shown in FIG. 12, the first drive lever 4 has been charged by a predetermined amount, and the second drive lever 5 has reached the charged position. When the cam gear 13 further rotates to the right, the roller 5i comes into contact with the cam surface of the charging area A2, and charging of the rear drive lever 5 is started. By charging the first drive lever 4 by a predetermined amount first, the blades forming the slit overlap each other, and the shutter opening can be maintained in a shielded state while the first and second drive levers are being charged.

The set operation is the charging of the first drive lever 4 and the second drive lever 5 from the travel completion state to the overcharge state. While charging is being performed in the charging area A1 and the charging area A2, as shown in FIGS. 11 and 12, the pressure angles θ1 and θ2 are large, so it is necessary to charge a large load. Therefore, in the set operation, it is necessary to increase the voltage that drives the motor 18. On the other hand, by increasing the angles of the charge area A1 and the charge area A2, it is possible to reduce the pressure angles θ1 and θ2, that is, to reduce the load.

When the cam gear 13 further rotates to the right from the state shown in FIG. 12, at timing 310, the focal plane shutter 202 enters the overcharge state of each blade group shown in FIG. At this time, the roller 4i has reached the cam top area B1, and the roller 5i has reached the cam top area B2. As a result, both the first drive lever 4 and the second drive lever 5 enter an overcharged state in which charging is completed, and the setting is completed.
(5) Set release During the period from timing 310 to timing 312, set release is performed. At timing 310, the motor 18 continues to be energized in the forward rotation direction. The roller 4i and the roller 5i pass through the cam surface of the cam top region B1 and the cam surface of the cam top region B2, respectively. At this time, energization to the forward electromagnet 22a is started, causing the armature 4d and the forward electromagnet 22a to attract each other. Also, energization to the rear electromagnet 22b is started, causing the armature 5d and the rear electromagnet 22b to attract each other. Thereby, after the setting is released, the first drive lever 4 and the second drive lever 5 are held.

At timing 311, the focal plane shutter 202 enters the state where each blade group in FIG. 14 starts to be released. The roller 4i and the roller 5i are in contact with the cam surfaces of the cam slope area C1 and the cam slope area C2, respectively. That is, the first drive lever 4 and the second drive lever 5 gradually transition from the overcharge state to the set release state. Note that the timing at which the roller 4i moves from the cam surface of the cam top area B1 to the cam surface of the cam slope area C1 and the timing at which the roller 5i moves from the cam surface of the cam top area B2 to the cam surface of the cam slope area C2 are the same. It is. After the phase contact piece 25 detects that the cam gear 13 has rotated to the right to a phase where the first drive lever 4 and the second drive lever 5 can travel, the motor 18 stops at timing 312. At this time, the focal plane shutter 202 is in a state where each blade group in FIG. 15 is released.
(6) Leading Blade Travel During the period from timing 312 to timing 315, leading blade traveling is performed. When a predetermined period of time has elapsed after the motor 18 has stopped, at timing 313, the energization to the forward electromagnet 22a is canceled, and the forward drive lever 4 is biased by the forward drive spring 6 and starts running from the state shown in FIG. 15. . At timing 314, the blade operating pin 4a collides with the buffer member 30, so that the shutter opening is opened, and the focal plane shutter 202 enters the set release state shown in FIG. 9. The period from timing 302 to timing 314 constitutes one sequence of live view shooting.
(7) Rear curtain setting operation From timing 307 after shooting to timing 314 (from after shooting to the next shooting timing), the CPU 204 turns the second switch 211 ON/OFF, that is, in response to shooting instructions from the photographer. Detecting presence.

When there is a shooting instruction from the photographer, the focal plane shutter 202 returns to the state shown in FIG. 9, and then shooting is performed. If there is no shooting instruction from the photographer, the rear curtain setting operation is performed during the period from timing 315 to timing 317. At timing 315, energization of the motor 18 in the reverse direction is started, and the cam gear 13 rotates to the left from the state shown in FIG. At timing 316, the roller 5i comes into contact with the cam surface of the cam slope region C2, and the focal plane shutter 202 enters the trailing curtain setting operation start state as shown in FIG. The cam gear 13 is further shifted from the state shown in FIG. 16, and the rear drive lever 5 changes from the set release state to the overcharge state. At this time, since the charging angle is small from the release of the rear drive lever 5 to the overcharge state, and the pressure angle θ3 is small as shown in FIG. 16, there is no need to charge a large load. Therefore, the voltage driving motor 18 may be low.

At timing 317, after the phase contact piece 25 detects that the cam gear 13 has reached the cam top phase, the motor 18 stops. Further, the energization to the rear electromagnet 22b is also canceled. At this time, the focal plane shutter 202 is in a pre-release standby state as shown in FIG. The rear drive lever 5 is in an overcharged state and is held by the cam gear 13. The roller 4i has entered the notch 13d. Even if the cam gear 13 overruns due to inertia after the motor 18 stops, the rotation of the cam gear 13 is stopped by the roller 4i coming into contact with the notch end 13e of the notch 13d as shown in FIG. Therefore, the cam gear 13 can reliably stop at the live view phase.

As explained above, in this embodiment, the motor 18 is not stopped in a state in which the drive lever is in contact with the cam surface in the cam top area, regardless of the presence or absence of a shooting instruction from the photographer in one sequence. time can be shortened. In addition, when stopping the motor 18 with the drive lever in contact with the cam surface in the cam top area after the set operation, it is necessary to energize the motor 18 with a high voltage during the set operation. It is necessary to increase the size in consideration of overrun after stopping. However, as in this embodiment, when the motor 18 is energized in the reverse direction with a low voltage after the set is released and the drive lever is brought into contact with the cam surface in the cam top area, the overrun angle of the motor 18 is is small, allowing the cam top area to be shortened. That is, in one sequence, the time required for the drive lever to pass through the cam surface of the cam top area to release the setting from the setting operation can be shortened.

Furthermore, in this embodiment, the timings at which each drive lever moves from the cam top position to the set release position are the same. After the first drive lever 4 completes its travel, the second drive lever 5 is held by the cam surface in the cam top region by rotating the cam gear 13 in a direction opposite to the charging direction. That is, the screen shifts to a live view state. In the live view state (the state shown in FIG. 8), the roller 4i is inserted into the notch 13d, so that it is possible to prevent the first drive lever 4 from interfering with the cam gear 13. With such a configuration, the cam phase in the live view state and the cam phase in the charge completion state (the state shown in FIG. 13) can be made the same. Therefore, there is no need for a dedicated phase for live view. Since a dedicated phase for live view is not required, the cam phase in the charge area can be increased, the load required for charging is reduced, and current consumption can be reduced. Therefore, even if the gear ratio is increased, deterioration in current consumption can be suppressed and the frame speed can be increased.

As explained above, according to the configuration of this embodiment, it is possible to save power and increase the frame rate.

Note that in this embodiment, the sequence and configuration of live view shooting using the electronic front curtain have been described, but the present invention is not limited thereto. The present invention can also be applied to normal photography using the leading blade group 42 and the trailing blade group 43. In that case, the operation of the front drive lever 4 is the same as the operation of the rear drive lever 5, and the front blade group 42 only needs to run instead of the electronic front curtain.

FIG. 18 is an exploded perspective view of the drive lever side of the focal plane shutter 202 of this embodiment viewed from the subject side. In FIG. 18, the configuration that overlaps with FIG. 2 of the first embodiment is omitted. The focal plane shutter 202 of this embodiment differs from the first embodiment in that a motor and a cam gear are provided for each drive lever. The shutter base plate 60 has an opening 60a, a front drive lever shaft 60b, a rear drive lever shaft 60c, a front cam gear shaft 60d, and a rear cam gear shaft 60e. The front cam gear 61 has only a cam portion 61a that slides on the roller 4i attached to the front drive lever 4. The shape of the cam portion 61a is similar to the shape of the tip cam portion 13a. The rear cam gear 62 only has a cam portion 62a that slides on the roller 5i attached to the rear drive lever 5. The shape of the cam portion 62a is similar to the shape of the rear cam portion 13b. A phase contact piece 25 is attached to each of the front cam gear 61 and the rear cam gear 62. Each phase contact piece is used to detect the rotational phase of the respective cam gear. The front pinion gear 67 and the rear pinion gear 68 are attached to the front motor 65 and the rear motor 66, respectively. The driving force of the front motor 65 is transmitted to the front cam gear 61 via the front pinion gear 67 and the front gear 63. The driving force of the rear motor 66 is transmitted to the rear cam gear 62 via a rear pinion gear 68 and a rear gear 64. In this embodiment, the front cam gear 61 and the rear cam gear 62 can be driven independently.

FIG. 19 is a time chart showing the operation of each component during live view shooting.
(1) Pre-release standby state At timing 401, the focal plane shutter 202 is in a pre-release standby state. The leading blade group 42 is in a running completed state, and the rear drive lever 5 is in an overcharged state.
(2) Set release During the period from timing 402 to timing 404, set release is performed. During this period, the forward drive lever 4 is in a state of completion of travel, and the forward motor 65 is not energized. At timing 402, when the CPU 204 receives the release signal, energization of the rear motor 66 in the forward rotation direction is started, and the rear cam gear 62 starts rotating to the right. Furthermore, energization of the rear electromagnet 22b is started. At timing 403, the roller 5i comes into contact with the cam slope area C2. The rear drive lever 5 transitions from the overcharge state to the set release state. After the phase contact piece 25 detects that the cam portion 62a has retreated from the travel locus of the drive lever 5 and the rear cam gear 62 has rotated to the right to a phase where the rear drive lever 5 can travel, at timing 404, the rear cam gear 62 is rotated to the right. Motor 66 stops. At this time, the focal plane shutter 202 is in a set release state.
(3) Photographing Photography is performed during the period from timing 404 to timing 407. This operation is the same as in the first embodiment, so its explanation will be omitted.
(4) Set operation During the period from timing 407 to timing 410, the front drive lever 4 and the rear drive lever 5 are charged against the biasing forces of the front drive spring 6 and the rear drive spring 7, and the drive lever 4 and the rear drive lever 5 are charged to move from the running completion state to overdrive. A setting operation is performed to set the charging state. At timing 407, energization of the forward motor 65 in the forward rotation direction is started, and the forward cam gear 61 starts rotating to the right. At timing 408, the first drive lever 4 reaches the charged position. After the front drive lever 4 has been charged by a predetermined amount, energization of the rear motor 66 in the forward rotation direction is started, and the rear drive lever 5 reaches the position where it is charged. By starting energizing the front motor 65 earlier than energizing the rear motor 66 and charging the front drive lever 4 by a predetermined amount first, the blades forming the slit overlap each other and the front and rear drive levers are being charged. The shutter opening can be kept in a shielded state.
(5) Set release During the period from timing 410 to timing 412, set release is performed. This operation is the same as in the first embodiment, so its explanation will be omitted.
(6) Leading Blade Travel During the period from timing 412 to timing 415, leading blade traveling is performed. This operation is the same as in the first embodiment, so its explanation will be omitted.
(7) Rear Curtain Set Operation From timing 407 to timing 414 after photography, the CPU 204 detects the presence or absence of a photography instruction from the photographer.

When there is a shooting instruction from the photographer, the focal plane shutter 202 returns to the set release state and shooting continues. If there is no shooting instruction from the photographer, the rear curtain setting operation is performed during the period from timing 415 to timing 417. At timing 415, energization of the rear motor 66 in the reverse direction is started, and the rear cam gear 62 rotates to the left. At timing 416, the focal plane shutter 202 enters the trailing curtain setting operation start state. When the rear cam gear 62 further rotates to the left, the rear drive lever 5 transitions from the set release state to the overcharge state.

At timing 417, after the phase contact piece 25 detects that the rear cam gear 62 has reached the cam top phase, the rear motor 66 stops. Further, the energization to the rear electromagnet 22b is also canceled. At this time, the focal plane shutter 202 is in a pre-release standby state. The rear drive lever 5 is in an overcharged state and is held by the rear cam gear 62. On the other hand, the forward motor 65 is not energized, and the forward drive lever 4 maintains the travel completed state.

As explained above, in this embodiment, the motor 18 is not stopped in a state in which the drive lever is in contact with the cam surface in the cam top area, regardless of the presence or absence of a shooting instruction from the photographer in one sequence. time can be shortened. This makes it possible to increase the frame speed.

Furthermore, by providing cam gears and corresponding motors for charging the first drive lever 4 and the second drive lever 5, the load to be charged can be divided into two. Thereby, the output of the motor can be made low torque, so a small motor can be used. That is, the focal plane shutter 202 including the motor can be downsized. Furthermore, by using two motors, the motors are not energized during the period when the first drive lever 4 does not need to be operated, so power can be saved.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention.

1 Shutter base plate (base plate)
1a Opening 4 First drive lever (first drive member)
5 Rear drive lever (second drive member)
6 First drive spring (first biasing member)
7 Rear drive spring (second biasing member)
13 Cam gear (cam member)
18 Motor (drive means)
42 Lead blade group (first blade group)
43 Rear blade group (second blade group)
60 Shutter base plate (base plate)
60a Opening 62 Rear cam gear (cam member)
66 Rear motor (drive means)
202 Focal plane shutter (shutter device)

Claims (10)

a base plate provided with an opening through which light passes;
a first driving member that drives the first blade group;
a second drive member that drives the second blade group;
a first biasing member that biases a first drive member such that the first blade group moves from a closed state in which the opening is closed to an open state in which the opening is opened;
a second biasing member that biases a second drive member so that the second blade group moves from the open state to the closed state;
A shutter device including a cam member attached to a rotating shaft provided on the base plate and rotatable about the rotating shaft by a driving means,
a reference position of the cam member when the shutter device is in a first state in which the first and second driving members are held by the cam member while the first and second biasing members are charged; The rotation angle range for the shutter device is such that the first blade group is in the open state, the second biasing member is charged, and the second driving member is held by the cam member. A shutter device characterized in that the rotation angle range of the cam member with respect to the reference position is the same as in the second state. The timing at which the first driving member comes out of the state where the first biasing member is held by the cam member while the first biasing member is charged is when the second driving member is released from the state where the second biasing member is charged. 2. The shutter device according to claim 1, wherein the timing coincides with the timing at which the shutter device exits from the state held by the cam member. The shutter device transitions to the first state by driving the driving means in a first direction, and transitions to the second state by driving the driving means in a second direction opposite to the first direction. The shutter device according to claim 1 or 2, characterized in that: The shutter device according to any one of claims 1 to 3, wherein the cam member has a notch in which the first drive member is arranged in the second state. The cam member is a first cam member capable of holding the first driving member with the first biasing member charged, and a first cam member capable of holding the second driving member with the second biasing member charged. 5. The shutter device according to claim 1, further comprising a second cam member. The first cam member has a first area for holding a cam follower of the first drive member at a cam top position, and a first area for transitioning the first drive member from a state held by the cam member to a drivable state. and a second area of
The second cam member has a third area for holding the cam follower of the second drive member at a cam top position, and a third area for transitioning the second drive member from a state held by the cam member to a drivable state. 6. The shutter device according to claim 5, further comprising a fourth region. Two of the first cam members and two of the second cam members are provided, and each of the first cam members and the second cam member is arranged point-symmetrically with respect to the rotation center of the cam member. The shutter device according to claim 5 or 6, characterized in that: 7. The shutter device according to claim 5, wherein the driving means includes a first driving means for driving the first cam member and a second driving means for driving the second cam member. 9. The shutter device according to any one of claims 1 to 8, wherein the shutter device is capable of shifting to the first state or the second state by integrally rotating the cam member. The shutter device described. A shutter device according to any one of claims 1 to 9,
An imaging device comprising: an imaging element whose exposure amount is controlled by the shutter device.