JP2020173325A - Imaging device - Google Patents

Abstract

To provide an imaging device with which it is possible to raise a frame speed without increasing costs.SOLUTION: The imaging device comprises: a first urging member for urging a first drive member that drives a first blade group so that the first blade group moves from a closed state where an opening is closed and an open state where the opening is opened; a second urging member for urging a second drive member that drives a second blade group so that the second blade group moves from the open state to the closed state; a cam member having a first phase in which the second drive member is held while the second urging member is charged and a second phase in which the second drive member is made drivable; and control means for driving drive means that drives the cam member in a first direction until the cam member passes through the first phase and reaches the second phase after first imaging, and when an imaging indication is dropped before second imaging is performed after the first imaging, driving the drive means in a second direction which is opposite the first direction until the cam member reaches the first phase after the second phase.SELECTED DRAWING: Figure 7

Description

The present invention relates to an imaging device having a focal plane shutter.

As a focal plane shutter for a camera, a slit formed by two blade groups attached to a shutter base plate is known to continuously expose an imaging surface. Further, two drive members are attached to the shutter base plate, each of which is driven by an urging member to operate each blade group. Further, a motor that drives a cam gear that charges the drive member to the 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 turning off the power to stopping depends on the applied voltage and the usage environment. Therefore, a sufficient motor idle section is provided on the cam top of the cam gear so that the overcharged state is ensured even when the motor overruns most.

According to Patent Document 1, when the switch instructing the start of the imaging operation is turned on after the charging of the urging member by the charging means is completed, the charging means is driven to the running ready state without stopping in the overcharged state. The imaging device is disclosed.

Japanese Unexamined Patent Publication No. 2011-53375

However, in the image pickup apparatus of Patent Document 1, when the switch is off, the charging means is stopped in the overcharged state, so that it is necessary to lengthen the motor idle section for overrun. Therefore, when the continuous shooting instruction is given, it takes a long time to pass through the cam top section of the cam gear, and it takes time until the next shooting. Therefore, it is difficult to increase the frame speed of the camera. In order to increase the frame speed, there are countermeasures such as increasing the motor characteristics and reducing the urging force of the urging member by replacing the blade material with a lighter one, but both methods increase the cost. It ends up.

An object of the present invention is to provide an imaging device capable of increasing the frame speed without increasing the cost.

The imaging device as one aspect of the present invention is an imaging device that performs imaging according to an imaging instruction of the photographer, and includes a main plate provided with an opening through which light passes, and a first driving member that drives the first blade group. , The second driving member that drives the second blade group, and the first urging member that urges the first driving member so that the first blade group moves from the closed state in which the opening is closed to the open state in which the opening is opened. The second urging member that urges the second driving member so that the second blade group moves from the open state to the closed state, and the second driving member that holds the second driving member in a charged state. A cam member having a first phase and a second phase that enables the second driving member to be driven, a driving means for driving the cam member, and a second phase after the cam member passes through the first phase after the first photographing. When the driving means is driven in the first direction until it reaches, and the shooting instruction is released between the first shooting and the next second shooting, the cam member moves from the second phase to the first. It is characterized by having a control means for driving the drive means in a second direction opposite to the first direction until the phase is reached.

According to the present invention, it is possible to provide an image pickup apparatus capable of increasing the frame speed without increasing the cost.

It is a block diagram of the image pickup apparatus which concerns on embodiment of this invention. It is an exploded perspective view of the focal plane shutter of Example 1. FIG. It is a perspective view of the drive lever of the focal plane shutter of Example 1. FIG. It is a figure which shows the cam gear of the focal plane shutter of Example 1. FIG. It is a perspective view of the upper base plate of the focal plane shutter of Example 1. FIG. It is an exploded perspective view of the motor unit of the focal plane shutter of Example 1. FIG. It is a time chart which shows the operation of each component of the focal plane shutter of Example 1. FIG. It is a figure which shows the standby state before release of the focal plane shutter of Example 1. FIG. It is a figure which shows the set release state of the focal plane shutter of Example 1. FIG. It is a figure which shows the traveling completion state of the rear blade group of the focal plane shutter of Example 1. FIG. It is a figure which shows the charge start state of the forward drive lever of the focal plane shutter of Example 1. FIG. It is a figure which shows the charge start state of the rear drive lever of the focal plane shutter of Example 1. FIG. It is a figure which shows the overcharge state of each blade group of the focal plane shutter of Example 1. FIG. It is a figure which shows the set release start state of each blade group of the focal plane shutter of Example 1. FIG. It is a figure which shows the set release state of each blade group of the focal plane shutter of Example 1. FIG. It is a figure which shows the rear curtain set operation start state of the focal plane shutter of Example 1. FIG. It is a figure which shows the state after the rear curtain set operation of the focal plane shutter of Example 1. FIG. It is an exploded perspective view of the focal plane shutter of Example 2. FIG. It is a time chart which shows the operation of each component of the focal plane shutter of Example 2. FIG.

Hereinafter, examples of the present invention will be described in detail with reference to the drawings. In each figure, the same member is given the same reference number, and duplicate description is omitted.

FIG. 1 is a block diagram of an image pickup apparatus 200 according to an embodiment of the present invention. The image pickup device 200 has an image pickup device main body having an image pickup element 203, and an image pickup lens (interchangeable lens, lens device, image pickup optical system) 201 that can be attached to and detached from the image pickup device main body. In the image pickup apparatus 200, it is possible to select a normal exposure method using the front and rear blades of the focal plane shutter, a reset scanning (electronic front curtain scanning), and an electronic front curtain method using the rear blades. In this embodiment, the image pickup lens 201 is removable from the image pickup device main body, but may be integrally configured with the image pickup device main body.

The subject light from the image pickup lens 201 goes toward the image pickup element 203. The image pickup lens 201 may have an aperture. The image pickup element 203 is composed of a CMOS image sensor or the like, and photoelectrically converts a subject image (optical image) formed by the image pickup lens 201. The focal plane shutter (shutter device) 202 is arranged on the subject side with respect to the image pickup element 203, and controls the exposure amount to the image pickup element 203. The CPU (control means) 204 controls and calculates the shutter drive circuit 205, the vertical drive modulation circuit (scanning means) 208, the signal processing circuit 209, and the lens control means 215. The CPU 204 controls the operation of the focal plane shutter 202 (start timing of blade group traveling and driving 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 a two-stage switch, the first switch 210 is turned on in the first stroke, and the second switch 211 is turned on in the second stroke.

The lens control means 215 provides imaging condition information (information regarding the state of the lens device, that is, a lens) such as the focal length of the image pickup lens 201, the aperture diameter (aperture value), the exit pupil diameter, and the distance between the exit pupil and the image pickup element 203. Information) is output to the CPU 204. Further, the lens control means 215 controls the operation (drive) of the image pickup lens 201 (including the aperture) in response to an instruction from the CPU 204.

The CPU 204 supplies a scanning clock (horizontal drive pulse) and a predetermined control pulse 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 pickup element 203. The vertical drive modulation circuit 208 is a scanning means as an electronic front curtain, and is a scanning pattern of reset scanning as an electronic front curtain, that is, a scan that starts charge accumulation for each pixel of the image sensor 203 based on a command of the CPU 204. Set (scanning curve). Further, the vertical drive modulation circuit 208 performs reset scanning in order from top to bottom or bottom to top based on an instruction 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 from the image sensor 203. The recording medium 212 records the image data generated by the signal processing circuit 209. The display unit 213 is composed of a liquid crystal display (LCD) or the like, and displays an image or various menu screens. The RAM (Random Access Memory) 214 is a storage means connected to the signal processing circuit 209 and temporarily storing 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 when the focal plane shutter 202 is viewed from the subject side, and FIG. 2B is an exploded perspective view of the vane chamber side when 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. 3A is a perspective view of the leading drive lever 4. FIG. 3B is a top view of the leading drive lever 4. FIG. 3C is a cross-sectional view of a portion used for attracting the front drive lever 4 to the front side electromagnet 22a. FIG. 3D is a perspective view of the rear drive lever 5. FIG. 3E is a top view of the rear drive lever 5. FIG. 3 (f) is a cross-sectional view of a portion used for attracting the rear drive lever 5 to the rear electromagnet 22b.

FIG. 4 is a diagram showing a cam gear (cam member) 13. FIG. 4A is a view of the cam gear 13 as viewed from above. FIG. 4B is a side view of the cam gear 13. FIG. 4C is a view of the cam gear 13 as viewed from the bottom surface.

FIG. 5 is a perspective view of the upper base plate 21. FIG. 5A is a view of the upper base plate 21 as viewed from the subject side. FIG. 5B is a view of the upper base plate 21 as viewed from the photographer 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 at the center. The shutter base plate 1 has a front drive lever shaft 1b, a rear drive lever shaft 1c, and a cam gear shaft 1d. Further, the shutter base plate 1 has a front main arm shaft 1e, a front sub-arm shaft 1f, a rear main arm shaft 1g, and a rear sub-arm shaft 1h.

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

A blade chamber for arranging a group of blades 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 front blade group 42 closes the shutter opening before exposure. The front blade group 42 has a main arm 42a and a sub arm 42b. The main arm 42a is rotatably attached to the front main arm shaft 1e, and the sub arm 42b is rotatably attached to the front sub arm shaft 1f.

Further, the front blade group 42 has 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 pivotally supported by a main arm 42a and a sub arm 42b so as to be rotatable by a pin 42g, and forms a parallel link.

The main arm 42a is provided with a hole 42h for engaging with the blade actuating pin 4a of the leading drive lever 4. The sub-arm 42b is hung with a tip backlash spring 44 that urges counterclockwise in FIG. 2B 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 has 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 axially supported by a main arm 43a and a sub arm 43b so as to be rotatable by a pin 43g, and forms a parallel link.

The main arm 43a is provided with a hole 43h for engaging with the blade actuating pin 5a of the rear drive lever 5. The sub-arm 43b is fitted with a backlash spring 45 that is urged counterclockwise in FIG. 2B so that the blades expand.

Further, spacers 41 are attached to the tip portions of the blades of the front blade group 42 and the rear blade group 43 to suppress the movement of each blade in the optical axis direction.

The movable end of the leading drive spring (first urging member) 6 is hooked on the leading drive lever 4, and the fixed end is hooked on the adjuster 10. The front drive spring 6 urges the front drive lever 4 so that the front blade group 42 moves from the deployed state (closed state) in which the shutter opening is closed to the superposed state (open state, running completed state) in which the shutter opening is opened. To do. The movable end of the rear drive spring (second urging member) 7 is hung on the rear drive lever 5, and the fixed end is hung on the ratchet 11. The rear drive spring 7 urges the rear drive lever 5 so that the rear blade group 43 moves from the superposed state (open state) in which the shutter opening is opened to the deployed state (closed state, running completed state) in which the shutter opening is closed. To do.

By rotating the adjuster 10 with the worm 12, the urging force of the leading drive spring 6 can be adjusted. By adjusting the urging force of the front drive spring 6, the traveling speed of the front blade group 42 can be set. The worm stopper 24 holds the worm 12 so as not to rotate after rotating the adjuster 10.

The ratchet 11 is arranged so that the central shaft is coaxial with the rear drive lever shaft 1c. The ratchet 11 is fixed by engaging the ratchet teeth 11a with the ratchet claws 21a of the upper base plate 21. Further, the urging 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 side electromagnet 22a, a rear side electromagnet 22b, and a flexible substrate (not shown) are fixed to the upper base plate 21. The terminals of each electromagnet are connected to the shutter drive circuit 205 via a flexible substrate (not shown). The magnet cover 23 is fixed to the upper base plate 21 so as to cover each electromagnet, and protects the suction portion of each electromagnet and the suction surface of the amateur of each drive lever from external dust.

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

The leading drive lever 4 includes a blade operating pin 4a, a roller shaft 4b, an amateur shaft 4c, an amateur 4d, an amateur guide portion 4e, an amateur rubber 4f, an amateur spring 4g, a PI shading portion 4h, a roller (cam follower) 4i, and a slit washer 4j. Have. The blade actuating pin 4a collides with the cushioning member 30 made of rubber or the like when the traveling of the front blade group 42 is completed. The amacha shaft 4c is crimped to the amacha 4d. The amateur guide unit 4e regulates the movement of the amateur 4d and assists the attraction to the front electromagnet 22a. The PI shading unit 4h detects the position of the leading drive lever 4 or the leading blade group 42 by switching the brightness of the PI (photo interrupter) (not shown) fixed to the upper base plate 21. The roller 4i is rotatably attached to the roller shaft 4b, and is pushed by the front cam portion 13a of the cam gear 13, which will be described later, to charge the front drive spring 6. The slit washer 4j is attached so that the roller 4i does not fall off from the roller shaft 4b.

The rear drive lever 5 includes a blade operating pin 5a, a roller shaft 5b, an amateur shaft 5c, an amateur 5d, an amateur guide portion 5e, an amateur rubber 5f, an amateur spring 5g, a PI shading portion 5h, a roller (cam follower) 5i, and a slit washer 5j. Have. The blade actuating pin 5a collides with the buffer member 30 when the rear blade group 43 has completed traveling. The amacha shaft 5c is crimped to the amacha 5d. The amateur guide unit 5e regulates the movement of the amateur 5d and assists the attraction to the rear electromagnet 22b. The PI shading unit 5h detects the position of the rear drive lever 5 or the rear blade group 43 by switching the brightness of the PI (photo interrupter) (not shown) fixed to the upper base plate 21. The roller 5i is rotatably attached to the roller shaft 5b, and is pushed by the rear cam portion 13b of the cam gear 13, which will be described later, to charge the rear drive spring 7. The slit washer 5j is attached so that the roller 5i does not fall off from the roller shaft 5b.

The front cam portion 13a and the rear cam portion 13b are each formed in pairs at points symmetrical with respect to the rotation center of the cam gear 13.

The front cam portion 13a has a charge region A1 that charges the front drive spring 6 to the charge completion position (cam top position) via the roller 4i. Further, the front cam portion 13a is formed concentrically with the rotation center of the cam gear 13, and the cam top region B1 capable of holding the front drive spring 6 at the charge completion position and the front drive spring 6 are moved from the charge completion position to the set release position. It has a cam tilt region C1 for shifting.

The front cam portion 13a has a notch portion 13d. The cutout portion 13d is a space for the roller 4i to enter in the live view state described later. By providing the notch portion 13d, it is possible to secure a long live view phase. The notch portion 13d has a notch end portion 13e that faces the roller 4i when transitioning to the live view state.

The rear cam portion 13b has a charge region A2 that charges the rear drive spring 7 to the charge completion position (cam top position) via the roller 5i. Further, the rear cam portion 13b is formed concentrically with the rotation center of the cam gear 13, and the cam top region B2 capable of holding the rear drive spring 7 at the charge completion position and the rear drive spring 7 are moved from the charge completion position to the set release position. It has a cam tilt region C2 for shifting.

When the gear portion 13c meshes with the third reduction gear 16, the forward rotation direction (first direction) or the reverse rotation direction (first direction) of the motor 18 or the reverse rotation direction (first direction) of the motor 18 via the second reduction gear 15, the first reduction gear 14, and the pinion gear 17 It rotates according to the rotation in the second direction).

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

Hereinafter, the operation of each component of the focal plane shutter 202 will be described 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 state of the focal plane shutter 202.
(1) Pre-release standby state At the timing 301, the focal plane shutter 202 is the pre-release standby state shown in FIG. The front blade group 42 is in the traveling completed state, and the roller 4i has entered the notch portion 13d. The roller 5i is in contact with 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 opening is open, and the image pickup apparatus 200 is in the live view state. In the state of FIG. 8, in order to guarantee the suction state of the amateur 5d and the rear side electromagnet 22b, the rear drive lever 5 is rotated more than the position where the rear side electromagnet 22b attracts the rear drive lever 5. Therefore, the state shown in FIG. 8 is also referred to as an overcharged state. This play is absorbed by creating a gap between the amateur rubber 5f and the rear drive lever 5.
(2) Release of set The set is released during the period from timing 302 to timing 304. During this period, the leading drive lever 4 is in the traveling completed state, and the motor 18 is not energized. When the CPU 204 receives the release signal at the timing 302, 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. In addition, energization of the rear electromagnet 22b is started. At the timing 303, the roller 5i comes into contact with the cam surface of the cam inclination region 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 is in the released state in which the overcharge state is released. As a result, the rear drive lever 5 can be driven (driven) by the rear drive spring 7, but the rear electromagnet 22b is energized and the amateur 5d and the rear electromagnet 22b are attracted to each other. ,Stop. That is, the gap between the amateur rubber 5f and the rear drive lever 5 caused by overcharging is eliminated, and the rear drive lever 5 is held in a state where the amateur rubber 5f is further compressed and balanced with the load of the rear drive spring 7. After the phase contact piece 25 detects that the rear cam portion 13b has retracted from the drive locus of the rear drive lever 5 and the cam gear 13 has turned to the right to the phase in which the rear drive lever 5 can travel, at the timing 304, The motor 18 stops. At this time, the focal plane shutter 202 is in the set release state of FIG.
(3) Shooting Shooting is performed during the period from timing 304 to timing 307. At the timing 304, when a predetermined time elapses after the motor 18 is stopped, the image sensor 203 starts the electronic front curtain scanning. At the timing 305, the energization of the rear electromagnet 22b is released. The exposure time of the image sensor 203 is determined by the electronic front curtain that imitates the slit of the first blade 42c and the timing of releasing the energization of the rear electromagnet 22b. The rear drive lever 5 is urged by the rear drive spring 7 and starts traveling from the state shown in FIG. At the timing 306, the blade actuating pin 5a collides with the buffer member 30, and the rear blade group 43 completes traveling. At this time, the focal plane shutter 202 is in the traveling completed state of the rear blade group 43 in FIG. After that, it is necessary to elapse a predetermined time (in this embodiment, the period from timing 306 to timing 307) from the completion of traveling of the rear blade group 43 until the shaking of each blade stabilizes.
(4) Set operation During the period from timing 307 to timing 310, the front drive lever 4 and the rear drive lever 5 are overcharged (charged) from the running completion state against the urging force of the front drive spring 6 and the rear drive spring 7. The set operation to set to the completed state) is performed. At the 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 the timing 308, the leading drive lever 4 reaches the charged position. The focal plane shutter 202 is in the charge start state of the advance drive lever 4 shown in FIG. When the cam gear 13 is further rotated to the right, the roller 4i comes into contact with the cam surface of the charge region A1 and charging of the leading drive lever 4 is started. At the timing 309, the focal plane shutter 202 is in the charge start state of the rear drive lever 5 of FIG. As shown in FIG. 12, the front drive lever 4 is charged by a predetermined amount, and the rear drive lever 5 has reached the charged position. When the cam gear 13 further turns to the right, the roller 5i comes into contact with the cam surface of the charge region 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 slits overlap each other, and the shutter opening can be kept shielded during the charging of the first and subsequent drive levers.

The set operation is the charging of the front drive lever 4 and the rear drive lever 5 from the traveling completed state to the overcharged state. While charging is performed in the charging area A1 and the charging area A2, since the pressure angles θ1 and θ2 are large as shown in FIGS. 11 and 12, it is necessary to charge a large load. Therefore, in the set operation, it is necessary to increase the voltage for driving the motor 18. On the other hand, by increasing the angles of the charge area A1 and the charge area A2, the pressure angles θ1 and θ2 can be reduced, that is, the load can be reduced.

When the cam gear 13 is further rotated to the right from the state shown in FIG. 12, at the timing 310, the focal plane shutter 202 is in the overcharged state of each blade group shown in FIG. At this time, the roller 4i has reached the cam top region B1 and the roller 5i has reached the cam top region B2. As a result, both the front drive lever 4 and the rear drive lever 5 are in an overcharged state in which charging is completed, and the setting is completed.
(5) Release of set The set is released during the period from timing 310 to timing 312. At the timing 310, the motor 18 is continuously energized in the forward rotation direction. The rollers 4i and 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 of the front side electromagnet 22a is started, and the amateur 4d and the front side electromagnet 22a are attracted to each other. Further, energization of the rear side electromagnet 22b is started, and the amateur 5d and the rear side electromagnet 22b are attracted to each other. As a result, the front drive lever 4 and the rear drive lever 5 are held after the set is released.

At the timing 311 the focal plane shutter 202 is in the set release start state of each blade group shown in FIG. The rollers 4i and 5i are in contact with the cam surfaces of the cam inclination region C1 and the cam inclination region C2, respectively. That is, the front drive lever 4 and the rear drive lever 5 gradually transition from the overcharge state to the set release state. The timing at which the roller 4i shifts from the cam surface of the cam top region B1 to the cam surface of the cam tilt region C1 and the timing at which the roller 5i shifts from the cam surface of the cam top region B2 to the cam surface of the cam tilt region C2 are simultaneous. Is. After the phase contact piece 25 detects that the cam gear 13 has turned to the right to the phase in which the front drive lever 4 and the rear drive lever 5 can travel, the motor 18 stops at the timing 312. At this time, the focal plane shutter 202 is in the set release state of each blade group shown in FIG.
(6) Front blade traveling The front blade travel is performed during the period from timing 312 to timing 315. When a predetermined time elapses after the motor 18 is stopped, the energization of the front electromagnet 22a is released at the timing 313, and the front drive lever 4 is urged by the front drive spring 6 to start traveling from the state shown in FIG. .. At the timing 314, when the blade actuating pin 4a collides with the buffer member 30, the shutter opening is opened, and the focal plane shutter 202 is in the unset state shown in FIG. The period from timing 302 to timing 314 is one sequence of live view shooting.
(7) Rear curtain set operation During the period from timing 307 to timing 314 after shooting (between the shooting and the next shooting timing), the CPU 204 turns the second switch 211 ON / OFF, that is, the shooting instruction from the photographer. The presence or absence is detected.

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 set operation is performed during the period from timing 315 to timing 317. At the timing 315, energization of the motor 18 in the reverse direction is started, and the cam gear 13 turns counterclockwise from the state shown in FIG. At the timing 316, the roller 5i comes into contact with the cam surface of the cam tilt region C2, and the focal plane shutter 202 is in the rear curtain set operation start state of FIG. The cam gear 13 further shifts to the left from the state shown in FIG. 16, and the rear drive lever 5 shifts from the set release state to the overcharge state. At this time, the charge is performed at a small angle from the release of the rear drive lever 5 to the overcharge state, and since the pressure angle θ3 is small as shown in FIG. 16, it is not necessary to charge a large load. Therefore, the voltage for driving the motor 18 may be low.

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

As described above, in the present embodiment, the motor 18 is not stopped in the state where the drive lever is in contact with the cam surface in the cam top region regardless of the presence or absence of the photographer's shooting instruction in one sequence. Time can be shortened. Further, when the motor 18 is stopped in a state where the drive lever is in contact with the cam surface in the cam top region after the set operation, the motor 18 needs to be energized with a high voltage in the set operation, so that the cam top region is covered with the motor 18. It is necessary to increase it in consideration of the overrun after the stop. 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 region, the overrun angle of the motor 18 is reached. Is small and the cam top area can be shortened. That is, in one sequence, it is possible to shorten the time for the drive lever to pass through the cam surface in the cam top region and release the set from the set operation.

Further, in this embodiment, the timing at which each drive lever shifts from the cam top position to the set release position is the same. Then, after the traveling of the front drive lever 4 is completed, the rear drive lever 5 is held by the cam surface in the cam top region by rotating the cam gear 13 in the direction opposite to the charge direction. That is, it shifts to the live view state. In the live view state (state of FIG. 8), since the roller 4i has entered the notch portion 13d, it is possible to prevent the leading 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 complete state (state in FIG. 13) can be made common. Therefore, the phase dedicated to live view becomes unnecessary. Since the phase dedicated to live view is not required, the cam phase in the charge region can be increased, the load required for charging can be reduced, and the current consumption can be reduced. Therefore, even if the gear ratio is increased, the deterioration of the current consumption can be suppressed and the frame speed can be increased.

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

In this embodiment, the sequence and configuration in the live view shooting using the electronic front curtain have been described, but the present invention is not limited to this. The present invention can also be applied to normal photographing using the front blade group 42 and the rear 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 may travel 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 as viewed from the subject side. In FIG. 18, a configuration overlapping with FIG. 2 of the first embodiment is omitted. The focal plane shutter 202 of the present embodiment is different 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 with a roller 4i attached to the front drive lever 4. The shape of the cam portion 61a is the same as the shape of the front cam portion 13a. The rear cam gear 62 has only a cam portion 62a that slides with a roller 5i attached to the rear drive lever 5. The shape of the cam portion 62a is the same as 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 the rear pinion gear 68 and the 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 the pre-release standby state. The front blade group 42 is in the traveling completed state, and the rear drive lever 5 is in the overcharged state.
(2) Release of set The set is released during the period from timing 402 to timing 404. During this period, the leading drive lever 4 is in the traveling completed state, and the leading motor 65 is not energized. When the CPU 204 receives the release signal at the timing 402, energization of the rear motor 66 in the forward rotation direction is started, and the rear cam gear 62 starts turning to the right. In addition, energization of the rear electromagnet 22b is started. At timing 403, the roller 5i comes into contact with the cam tilt region 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 retracted from the traveling locus of the drive lever 5 and the rear cam gear 62 has rotated to the right to the phase in which the rear drive lever 5 can travel, the rear is rearward at the timing 404. The motor 66 stops. At this time, the focal plane shutter 202 is in the set release state.
(3) Shooting Shooting is performed during the period from timing 404 to timing 407. Since this operation is the same as that of the first embodiment, the description thereof 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 urging force of the front drive spring 6 and the rear drive spring 7, and the traveling is over from the completed state. The set operation to set the charge state is performed. At the timing 407, energization of the front motor 65 in the forward rotation direction is started, and the front cam gear 61 starts turning to the right. At the timing 408, the leading drive lever 4 reaches the charged position. After the front drive lever 4 is 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 charged position. By starting energization of the front motor 65 earlier than energization of the rear motor 66 and charging the front drive lever 4 by a predetermined amount first, the blades forming the slits overlap each other, and the drive levers of the front and rear are being charged. The shutter opening can be kept shielded.
(5) Release of set The set is released during the period from timing 410 to timing 412. Since this operation is the same as that of the first embodiment, the description thereof will be omitted.
(6) Front blade traveling The front blade travel is performed during the period from timing 412 to timing 415. Since this operation is the same as that of the first embodiment, the description thereof will be omitted.
(7) Rear curtain set operation During the period from timing 407 to timing 414 after shooting, the CPU 204 detects the presence or absence of a shooting 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 is performed as it is. If there is no shooting instruction from the photographer, the rear curtain set operation is performed during the period from timing 415 to timing 417. At the timing 415, energization of the rear motor 66 in the reverse direction is started, and the rear cam gear 62 rotates counterclockwise. At the timing 416, the focal plane shutter 202 is in the rear curtain set operation start state. When the rear cam gear 62 further turns counterclockwise, the rear drive lever 5 transitions from the set release state to the overcharge state.

At the timing 417, the rear motor 66 is stopped after the phase contact piece 25 detects that the rear cam gear 62 has reached the phase of the cam top. In addition, the energization of the rear electromagnet 22b is also released. At this time, the focal plane shutter 202 is in the standby state before release. The rear drive lever 5 is in an overcharged state and is held by the rear cam gear 62. On the other hand, the front motor 65 is not energized, and the front drive lever 4 maintains the traveling completed state.

As described above, in the present embodiment, the motor 18 is not stopped in the state where the drive lever is in contact with the cam surface in the cam top region regardless of the presence or absence of the photographer's shooting instruction in one sequence. Time can be shortened. This makes it possible to increase the frame speed.

Further, the load to be charged can be divided into two by providing a cam gear for charging the front drive lever 4 and the rear drive lever 5 and a motor corresponding thereto. As a result, the output of the motor can be made low torque, so that a small motor can be used. That is, the focal plane shutter 202 including the motor can be miniaturized. Further, by using two motors, the motors are not energized during the period when the advance drive lever 4 does not need to be operated, so that power saving can be achieved.

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

1 Shutter base plate (base plate)
1a Aperture 4 Tip drive lever (1st drive member)
5 Rear drive lever (second drive member)
6 Lead drive spring (first urging member)
7 Rear drive spring (second urging member)
13 Cam gear (cam member)
18 motor (driving means)
42 Tip blade group (1st 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 (driving means)
200 Imaging device 204 CPU (control means)

Claims (6)

It is an imaging device that shoots according to the shooting instructions of the photographer.
A main plate with an opening through which light can pass,
The first driving member that drives the first blade group and
The second driving member that drives the second blade group and
A first urging member that urges the first driving 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.
A second urging member that urges the second driving member so that the second blade group moves from the open state to the closed state.
A cam member having a first phase for holding the second driving member in a charged state of the second urging member and a second phase for driving the second driving member.
A driving means for driving the cam member and
After the first photographing, the driving means is driven in the first direction until the cam member passes through the first phase and reaches the second phase, and after the first photographing, the next second If the imaging instruction is released before imaging is performed, the driving means is driven in a second direction opposite to the first direction until the cam member reaches the first phase from the second phase. An image pickup apparatus having a control means for the operation. The cam member holds the first and second driving members in a state where the first and second urging members are charged in the first phase, and the first and second driving members in the second phase. The imaging device according to claim 1, wherein the member can be driven. When the phase of the cam member reaches the first phase by the time it reaches the second phase, the first and second driving members are charged with the first and second urging members. Held in
When the phase of the cam member changes from the second phase to the first phase, the first blade group is in the open state, and the second driving member is in a state in which the second urging member is charged. The imaging device according to claim 1, wherein the image pickup device is held by a cam member. The shutter according to claim 3, wherein the cam member has a notch in which the first driving member is arranged when the phase of the cam member changes from the second phase to the first phase. apparatus. The cam member can hold the first cam member capable of holding the first driving member in a charged state of the first urging member and the second driving member in a state of being charged with the second urging member. The imaging apparatus according to any one of claims 1 to 4, further comprising a second cam member. The imaging 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.