JP7814906B2 - Shutter device and imaging device - Google Patents

Description

The present invention relates to a shutter device and an imaging device.

Normally, the curtain speed of focal plane shutters used in imaging devices such as digital single-lens reflex cameras and mirrorless cameras cannot be changed after being adjusted to a predetermined value during assembly.

Patent Document 1 discloses an imaging device that can adjust the curtain speed by combining electromagnetic force and spring force. Patent Document 2 discloses an imaging device that can adjust the curtain speed by combining motor power and spring force.

International Publication No. 2018/230170 International Publication No. 2018/230172

However, the imaging devices disclosed in Patent Documents 1 and 2 use dedicated actuators such as electromagnetic drivers and motors to adjust the curtain speed, which increases costs.

The present invention therefore provides a shutter device and an imaging device that can change the curtain speed without using a dedicated actuator.

A shutter device according to one aspect of the present invention comprises two sets of blades that open and close an exposure aperture, two drive members that respectively drive the two sets of blades between an open position and a closed position of the aperture, two cam gears that move the two drive members, respectively, two locking members that can lock the two drive members, respectively , and a drive auxiliary member that can push one of the two drive members , wherein a first shooting phase, which is the phase of one of the two cam gears in the rotational direction during shooting in a first mode, is different from a second shooting phase, which is the phase of one of the two cam gears in the rotational direction during shooting in a second mode, and the drive auxiliary member does not push one of the two drive members in the first shooting phase, but pushes one of the two drive members in the second shooting phase .

Other objects and features of the present invention are described in the following embodiments.

The present invention provides a shutter device and an imaging device that can change the curtain speed without using a dedicated actuator.

FIG. 1 is a perspective view of an imaging device according to an embodiment of the present invention. FIG. 1 is a block diagram of an imaging apparatus according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the shutter device according to the embodiment. FIG. 2 is a plan view of the shutter device in the present embodiment in a standby state for photographing. FIG. 2 is a perspective view of a main part of the shutter device according to the embodiment. 10 is a timing chart in the electronic front-curtain shooting mode in this embodiment. FIG. 2 is a plan view of the shutter device in a running standby state in the electronic front-curtain shooting mode in the present embodiment. FIG. 10 is a plan view of the shutter device at the start of a set operation in electronic front-curtain shooting mode in this embodiment. FIG. 10 is a plan view of the shutter device when the rear curtain setting operation is completed in electronic front-curtain photography mode in the present embodiment. 10 is a timing chart in the mechanical first-curtain shooting mode in this embodiment. FIG. 2 is a plan view of the shutter device in a running standby state in mechanical front-curtain photography mode in the present embodiment. FIG. 10 is a plan view of the shutter device at the start of a set operation in mechanical front-curtain photography mode in this embodiment. FIG. 10 is a plan view of the shutter device during a setting operation in mechanical first-curtain photography mode in the present embodiment. 5A and 5B are diagrams illustrating a cam shape of a rear cam gear in the present embodiment.

Embodiments of the present invention will be described in detail below with reference to the drawings.

First, referring to Figure 1, the external configuration of an image capture device 100 equipped with a shutter device (focal plane shutter) according to this embodiment will be described. Figure 1 is a perspective view of the image capture device 100. The top surface of the image capture device 100 is provided with a power button 110, a release button 130, and an accessory shoe 140 for attaching a photography accessory such as a flash device. The lens mount 150 is an attachment portion for a lens device (interchangeable lens) (not shown). Because the image capture device 100 is a mirrorless type image capture device that does not use a reflex mirror, the shutter curtain is open when the device is ready to capture in order to display a live view. Therefore, as shown in Figure 1, the imaging surface of the image sensor 203 is exposed when the lens device is removed.

Next, the internal configuration of the imaging device 100 will be described with reference to FIG. 2. FIG. 2 is a block diagram of the imaging device 100. The shutter device (focal plane shutter) 202 is provided between the imaging lens 201, which focuses light from a subject on the imaging optical path, and the imaging element 203, such as a CMOS image sensor, and adjusts the exposure time of the imaging element 203 in conjunction with the electronic front curtain operation of the imaging element 203. The imaging element 203 photoelectrically converts the subject image (optical image) focused by the imaging lens (imaging optical system) 201 provided in the lens device. The analog image signal output from the imaging element 203 is converted into a digital signal by the AFE (Analog Front End) 204. The digital image signal output from the AFE 204 undergoes various image processing, compression/expansion processing, etc. by the DSP (Digital Signal Processor) 205. The recording medium 206 records image data processed by the DSP 205. The display unit 207 uses a liquid crystal display (LCD) or the like and displays captured images, various menu screens, and the like. The TG (Timing Generator) 208 supplies a drive signal to the image sensor 203. The RAM 210 is connected to the DSP 205 and temporarily stores image data and the like. The shutter drive circuit 211 drives the shutter device 202. The CPU 209 controls the AFE 204, DSP 205, TG 208, and shutter drive circuit 211. The lens control means 212 outputs lens information such as the focal length of the imaging lens 201, the aperture diameter, the pupil diameter, and the distance between the pupil and the image sensor 203 to the CPU 209, and drives the aperture, lens, etc. according to the control of the CPU 209.

Next, the shutter device 202 will be described with reference to Figures 3(a), (b), 4(a), (b), and 5(a), (b). Figures 3(a) and (b) are exploded perspective views of the shutter device 202. Figure 3(a) is an exploded perspective view of the shutter device 202 as seen from the side where the image sensor 203 is attached (the image sensor side). Figure 3(b) is an exploded perspective view as seen from the side where the lens device is attached (the subject side). Figures 4(a) and (b) are plan views of the shutter device 202 in a standby state, with Figure 4(a) showing a plan view of the standby state as seen from the image sensor side and Figure 4(b) showing a plan view of the standby state as seen from the subject side. Figures 5(a) and (b) are perspective views of the main parts of the shutter device 202, with Figure 5(a) showing the configuration of the leading drive member 7 and leading cam gear 22 and Figure 5(b) showing the configuration of the rear drive member 8, rear drive auxiliary member 91, and rear cam gear 23. The leading cam gear 22 and the rear cam gear 23 are two cam gears that move (rotate) the leading driving member 7 and the rear driving member 8, respectively.

Partition plate 2 and cover plate 3 are attached in sequence, spaced a specified distance apart, to the subject side of shutter base plate 1. Similar-shaped apertures 1a, 2a, and 3a are formed in the three plate members -- shutter base plate 1, partition plate 2, and cover plate 3 -- and the rectangular opening (exposure aperture) formed by overlapping these three apertures defines the light beam passing through the shutter. Two blade chambers are formed between these three plate members, and within these blade chambers, shutter blades consisting of light-blocking blades and blade arms are individually arranged as leading blade group 4 and trailing blade group 5. Leading blade group 4 and trailing blade group are the two blade groups that open and close the exposure aperture.

To increase the strength of the shutter base plate 1 and to tighten the various metal shafts, a metal auxiliary base plate 6 is fastened to the shutter base plate 1 with screws. Axes 6a, 6b, 6c, 6d, 6e, 6f, and 6m are erected on the auxiliary base plate 6 on the image sensor side. A leading drive member 7, a trailing drive member 8, a trailing drive auxiliary member 91, a leading locking member 9, and a trailing locking member 10 are rotatably attached to axes 6a, 6b, 6c, and 6d, respectively. The trailing drive member 8 and the trailing drive auxiliary member 91 are both attached to axis 6b and share the same center of rotation. A leading drive source 24 and a trailing drive source 25 (both DC motors) are fastened to the subject side of the auxiliary base plate 6 with screws, respectively.

A gear base plate 26 is fastened with screws to the subject side of the auxiliary base plate 6. The leading cam gear 22 and the rear cam gear 23 are rotatably attached to shafts 26a and 26b, respectively, which are erected on the imaging element side of the gear base plate 26. A leading reduction gear group 27 is rotatably supported on shafts 26c and 26e on the imaging element side of the gear base plate 26, and a rear reduction gear group 28 is rotatably supported on shafts 26d and 26f. The leading reduction gear group 27 and the leading cam gear 22 are connected to the output shaft 24a of the leading drive source 24. The rear reduction gear group 28 and the rear cam gear 23 are similarly connected to the output shaft 25a of the rear drive source 25. In this way, the torque of the leading drive source 24 and the rear drive source 25 is transmitted to the leading cam gear 22 and the rear cam gear 23, respectively. The front drive source 24 and rear drive source 25 can be used in either forward or reverse rotation, and here, the direction in which the front cam gear 22 and rear cam gear 23 rotate counterclockwise in Figure 4(a) is defined as forward rotation.

Hereinafter, the rotation directions will be defined with reference to Figure 4(a). The leading driving member 7 is biased counterclockwise by the biasing force of the leading driving spring 12. The rear driving member 8 is biased counterclockwise by the biasing force of the rear driving spring 13. The leading driving member 7 and the rear driving member 8 are two driving members that drive the leading blade group 4 and the rear blade group 5, respectively, between the opening position and the closing position of the aperture.

The rear drive auxiliary member (drive auxiliary member) 91 is biased counterclockwise by the biasing force of the rear drive auxiliary spring 92 and is a boost lever configured to push (push) the rear drive member 8, one of the two drive members. The rear drive member 8 is configured to operate by receiving a counterclockwise push from the rear drive auxiliary member 91, with the presence or absence of a push differing depending on the shooting mode. During the setting operation, the front drive member 7 is rotated clockwise by the front cam gear 22 against the biasing force of the front drive spring 12. The rear drive member 8 and rear drive auxiliary member 91 are rotated clockwise by the rear cam gear 23 against the biasing forces of the rear drive spring 13 and rear drive auxiliary spring 92. In the standby state shown in FIG. 11, the leading driving member 7 and the rear driving member 8 are locked by engaging the locked portions 7a and 8a provided on the leading driving member 7 and the rear driving member 8 with the leading locking member 9 and the rear locking member 10, respectively. In other words, the leading locking member 9 and the rear locking member 10 are two locking members that can lock the leading driving member 7 and the rear driving member 8, respectively. The locking release members 51 and 52, together with the electromagnetic actuator base 50, form an electromagnetic actuator, and rotation of the locking release members 51 and 52 can actuate the leading locking member 9 and the rear locking member 10, respectively.

The leading drive member 7 and the rear drive member 8 are provided with leading drive pins 7b and rear drive pins 8b, respectively. These pins pass through three pairs of elongated holes 1b and 1c, 6g and 6h, and 3b and 3c in the shutter base plate 1, auxiliary base plate 6, and cover plate 3, and engage with elongated holes 4c and 5c in the blade arms 4a and 5a. Rollers 14 and 15 are rotatably attached to the leading drive member 7. Rollers 16 and 17 are rotatably attached to the rear drive member 8. A roller 93 is rotatably attached to the rear drive auxiliary member 91. The leading cam gear 22 efficiently sets the leading drive member 7 via rollers 14 and 15. The rear drive member 8 is efficiently set via rollers 16 and 17, and the rear drive auxiliary member 91 is efficiently set via rollers 93, both of which are efficiently set by the rear cam gear 23.

In this embodiment, the leading cam gear 22 is formed with cam surfaces 22a and 22b, and the rear cam gear 23 is formed with cam surfaces 23a, 23b, and 23c. The rollers 14 and 15 attached to the leading driving member 7, the roller 93 attached to the rear driving auxiliary member 91, and the rollers 16 and 17 attached to the rear driving member 8 sequentially come into contact with each other to perform the setting operation. This averages out the amount of rotation of the leading driving member 7, the rear driving member 8, the rear driving auxiliary member 91, and the leading cam gear 22 and the rear cam gear 23 during the setting operation, thereby reducing the maximum load during the setting operation. However, depending on the tolerances of the related components, the leading driving member 7, the rear driving member 8, and the rear driving auxiliary member 91 may not be able to be set within the allowable setting position. In such cases, the set positions of the leading driving member 7, the rear driving member 8, and the rear driving auxiliary member 91 can be adjusted by replacing the rollers 15, 17, and 93.

The blade phase detection means 29, blade phase detection means 30, and cam phase detection means 31 are non-contact optical phase detection means attached to the holding base plate 11, which is located on the imaging element side of the auxiliary base plate 6. In this embodiment, photointerrupters are used as the blade phase detection means 29, blade phase detection means 30, and cam phase detection means 31. On the other hand, the cam phase detection means 32 is a contact-type phase detection means. The blade phase is detected by determining the light-blocking state of the blade phase detection means 29 and blade phase detection means 30 by the detection target portions 7f and 8f of the leading driving member 7 and the trailing driving member 8. The cam phase of the leading cam gear 22 is detected by determining the light-blocking state of the cam phase detection means 31 by the detection target portion 22c. The cam phase of the rear cam gear 23 is detected by determining the position at which a phase detection contact (not shown) attached to the rear cam gear 23 contacts the cam phase detection means 32.

In this embodiment, the leading blade group 4 and the trailing blade group 5 each comprise two sets of blade arms 4a, 4b and 5a, 5b, and four sets of blades 4d, 4e, 4f, 4g and 5d, 5e, 5f, 5g. The leading blade group 4 has two blade arms 4a, 4b pivotally attached to shafts 6i, 6j on the subject side of the auxiliary base plate 6. The four blades 4d, 4e, 4f, 4g are pivotally supported to the blade arms 4a, 4b via a connecting shaft 33. A long hole 4c is formed in the blade arm 4a, and the leading drive pin 7b of the leading drive member 7 engages with it. The trailing blade group 5 has two blade arms 5a, 5b pivotally attached to shafts 6k, 6l on the subject side of the auxiliary base plate 6. The four blades 5d, 5e, 5f, and 5g are pivotally supported on blade arms 5a and 5b via connecting shafts 33. A long hole 5c is formed in blade arm 5a, and a rear drive pin 8b of a rear drive member 8 engages with it.

Next, with reference to Figures 4 to 14, the shooting operation during continuous shooting in this embodiment will be described. The shooting sequence in this embodiment is divided into two modes: electronic first-curtain shooting mode (second mode) and mechanical first-curtain shooting mode (first mode). Here, the mechanical first-curtain shooting mode is a mode in which exposure is performed using two slit forming portions of each of the two blade groups, and the electronic first-curtain shooting mode is a mode in which exposure is performed using the electronic shutter of the imaging device and one slit forming portion of the two blade groups.

Figure 6 is a timing chart showing the operation timing of each component of the shutter device 202 and the image sensor 203 in electronic front-curtain shooting mode. Figure 10 is a timing chart showing the operation timing of each component of the shutter device 202 and the image sensor 203 in mechanical front-curtain shooting mode. States (1) to (11) in Figure 6 and states (1) to (12) in Figure 10 correspond to the respective operating states described below.

First, the electronic front-curtain shooting mode will be explained. Figures 4(a) and (b) are plan views of the shutter device 202 in a shooting standby state. Figure 7 is a plan view of the shutter device 202 in a run standby state after the rear curtain has been released. Figure 8 is a plan view of the shutter device 202 in a state immediately before the setting operation after the rear curtain has completed its travel. Figure 9 is a plan view of the shutter device 202 in a state after the rear curtain has been set.

In the shooting standby state (state (1) in Figure 6), the shutter device 202 is in a state in which the travel of the leading driving member 7 has completed, as shown in Figures 4(a) and (b). Meanwhile, the rear driving member 8 is held by the cam top (cam top position) of the rear cam gear 23, and is in an overcharged state with a gap 8e between the locked portion 8a of the rear driving member 8 and the locking portion 10a of the rear locking member 10. Because the leading blade group 4 and the rear blade group 5 are retracted from the exposure opening, the subject light beam passes through the exposure opening. In the imaging device 100, a live view imaging operation is performed, and the subject image incident on the image sensor 203 is displayed on the display unit 207.

When the release button 130 of the imaging device 100 is pressed, the release operation begins (state (2) in Figure 6), and the rear drive member 8 is released from the set position. Power is applied to the rear drive source 25 in the forward direction, causing the rear cam gear 23 to rotate counterclockwise via the rear reduction gear group 28. The roller 17 leaves the cam surface 23b of the rear cam gear 23, and the roller 93 leaves the cam surface 23c of the rear cam gear 23. The rear drive member 8, rear drive auxiliary member 91, and rear blade group 5 rotate slightly counterclockwise together, releasing the overcharge state. At this time, the gap 8e between the locked portion 8a of the rear drive member 8 and the locking portion 10a of the rear locking member 10 disappears, and the locked portion 8a of the rear drive member 8 engages with the locking portion 10a of the rear locking member 10, causing the rear drive member 8 to stop at the travel start position. Additionally, under the bias of the rear drive auxiliary spring 92, the locked portion 91a of the rear drive auxiliary member 91 is stopped while pushing against the locked portion 8a of the rear drive member 8. After the rear cam gear 23 retreats (cam bottoms) from the travel range of the rear drive member 8 and the rear drive auxiliary member 91, the cam phase detection means 32 detects the second shooting phase shown in FIG. 6 and stops the rear drive source 25, entering the travel standby state shown in FIG. 7 (state (3) in FIG. 6).

After all pixels of the image sensor 203 are reset (state (4) in Figure 6), electronic front-curtain scanning begins (state (5) in Figure 6). The electronic front-curtain scanning has a scanning pattern that matches the running characteristics of the rear blade group 5 when the rear drive member 8 is pushed by the rear drive auxiliary member 91. After a time corresponding to the set shutter speed has elapsed, the locking release member 52 shown in Figure 3(a) strikes the pushing portion 10b of the rear locking member 10. This causes the rear locking member 10 to rotate counterclockwise around the shaft 6d, disengaging the locked portion 8a of the rear drive member 8 (state (6) in Figure 6). Then, from the running standby state shown in Figure 7, the rear drive member 8 and rear drive auxiliary member 91 are rapidly rotated counterclockwise around the shaft 6b by the biasing forces of the rear drive spring 13 and the rear drive auxiliary spring 92. The rotational speed at this time is faster than if the rear drive member 8 were not pushed by the rear drive auxiliary member 91. As the rear drive member 8 rotates, the rear drive pin 8b rotates the blade arm 5a counterclockwise, causing the rear blade group 5 to cover the exposure opening. The rear drive auxiliary member 91 comes into contact with the shaft 6m midway and stops.

After this, the rear drive member 8 continues to rotate without being pushed by the rear drive auxiliary member 91. The rear drive auxiliary member 91 pushes the rear drive member 8 only in part of its rotation because it requires less energy to achieve the desired curtain speed than if it were pushed over the entire rotation range. As the exposure operation continues, the slit-forming edge (slit-forming portion) 5h of the rear blade group 5 retracts below the exposure opening, and the rear drive pin 8b abuts against a stopping member (not shown), stopping the rear drive member 8. Figure 8 shows the blade travel completion state achieved in this way. When the travel of the rear blade group 5 ends and the image sensor 203 is completely shielded from light, charge readout scanning begins (state (7) in Figure 6).

A predetermined time after the rear blade group 5 has completed its travel, current is applied to the front drive source 24 in the forward direction (state (8) in Figure 6), causing the front cam gear 22 to rotate counterclockwise around shaft 26a. Accordingly, the front drive member 7 comes into contact with the front cam gear 22 and is rotated clockwise around shaft 6a against the biasing force of the front drive spring 12. A predetermined time after current is applied to the front drive source 24, and before the front drive member 7 reaches the cam top of the front cam gear 22, current is applied to the rear drive source 25 in the forward direction (state (9) in Figure 6), causing the rear cam gear 23 to rotate counterclockwise around shaft 26b. Accordingly, the rear drive auxiliary member 91 comes into contact with the rear cam gear 23 and is rotated clockwise around shaft 6b against the biasing force of the rear drive auxiliary spring 92. Next, the rear drive member 8 comes into contact with the rear cam gear 23 and is rotated clockwise around the shaft 6b against the biasing force of the rear drive spring 13.

Meanwhile, the movement of the leading blade group 4 and the trailing blade group 5 at this time is as follows. The leading drive pin 7b of the leading drive member 7 rotates the blade arm 4a clockwise, causing blades 4d, 4e, 4f, and 4g to move upward while reducing their mutual overlap. The rear drive pin 8b of the rear drive member 8 rotates the blade arm 5a clockwise, causing blades 5d, 5e, 5f, and 5g to move upward while increasing their mutual overlap. When the leading drive member 7 passes the cam top of the leading cam gear 22 and continues to rotate, the locked portion 7a of the leading drive member 7 engages with the locking portion 9a of the leading locking member 9, causing the leading drive member 7 to stop at the travel start position. The leading cam gear 22 continues to rotate, but after it retreats from the travel range of the leading drive member 7 (cam bottom), the cam phase detection means 31 detects the stop phase and stops power supply to the leading drive source 24.

Similarly, the rear drive member 8 continues to rotate, passing through the cam top of the rear cam gear 23, until the locked portion 8a of the rear drive member 8 engages with the locking portion 10a of the rear locking member 10, causing the rear drive member 8 to stop at the travel start position. The rear cam gear 23 continues to rotate, but after it retreats from the travel range of the rear drive member 8 (cam bottom), the cam phase detection means 32 detects the stop phase and stops powering the rear drive source 25 (state (10) in Figure 6).

Figure 9 shows the state after the rear curtain setting operation is complete. From here, the leading driving member 7 and leading blade group 4 begin to travel in order to transition to the live view state. The lock-release member 51 shown in Figure 3(a) strikes the pushing portion 9b of the leading locking member 9, causing the leading locking member 9 to rotate counterclockwise around the shaft 6c and disengage the locked portion 7a of the leading driving member 7. The biasing force of the leading driving spring 12 then causes the leading driving member 7 to rapidly rotate counterclockwise around the shaft 6a. This causes the leading driving pin 7b to rotate the blade arm 4a counterclockwise, causing the leading blade group 4 to open the exposure opening. When the slit-forming edge (slit-forming portion) 4h of blade 4d of the leading blade group 4 retracts below the exposure opening, the leading driving pin 7b abuts against a stopping member (not shown), stopping the leading driving member 7. The leading blade group 4 then completes its travel and enters the travel standby state shown in Figure 4.

After the leading blade group 4 has completed its travel, the leading drive source 24 is stopped, and the image sensor 203 begins live view imaging and preparations for capturing the next frame are made (state (10) in Figure 6). Once preparations for capturing the next frame are complete, the system returns to state (1) in Figure 6, and the series of imaging operations from state (1) to state (10) in Figure 6 are repeated.

Next, the mechanical front-curtain photography mode will be described. Figure 4 shows the shutter device 202 in a photography standby state. Figure 11 is a plan view of the shutter device 202 in a travel standby state after the rear curtain has been released. Figure 12 is a plan view of the shutter device 202 in a state immediately before the setting operation after the rear blade has completed travel. Figure 13 is a plan view of the shutter device 202 in a state when the rear cam gear 23 is in the cam bottom position of the cam surface 23c during the setting operation. Figures 14(a) and (b) show the cam shape of the rear cam gear 23, and Figure 14(a) shows the shape of the cam surface 23c of the rear cam gear 23, corresponding to the cross section A-A of the rear cam gear 23 shown in Figure 14(b).

In the shooting standby state (state (1) in Figure 10), the shutter device 202 is in a state in which the travel of the leading driving member 7 has completed, as shown in Figures 4(a) and (b). Meanwhile, the rear driving member 8 is held by the cam top of the rear cam gear 23, and is in an overcharged state with a gap 8e between the locked portion 8a of the rear driving member 8 and the locking portion 10a of the rear locking member 10. Because the leading blade group 4 and the rear blade group 5 are retracted from the exposure opening, the subject light beam passes through the exposure opening. In the imaging device 100, a live view imaging operation is performed, and the subject image incident on the image sensor 203 is displayed on the display unit 207.

When the release button 130 of the imaging device 100 is pressed, the setting and releasing operations of the front curtain and the setting and releasing operation of the rear curtain begin (state (2) in Figure 10), and current is applied to the front drive source 24 in the forward direction, causing the front cam gear 22 to rotate counterclockwise around shaft 26a. Accordingly, the front drive member 7 comes into contact with the front cam gear 22 and is rotated clockwise around shaft 6a against the biasing force of the front drive spring 12. At the same time, the setting and releasing operation of the rear drive member 8 is performed. Current is applied to the rear drive source 25 in the forward direction, causing the rear cam gear 23 to rotate counterclockwise via the rear reduction gear group 28. The roller 17 separates from the cam surface 23b of the rear cam gear 23, and the rear drive member 8 rotates slightly counterclockwise together with the rear blade group 5, thereby releasing the overcharge state. The gap 8e between the locked portion 8a of the rear driving member 8 and the locking portion 10a of the rear locking member 10 disappears, and the locked portion 8a of the rear driving member 8 engages with the locking portion 10a of the rear locking member 10, causing the rear driving member 8 to stop at the travel start position. After the rear cam gear 23 retreats from the travel range of the rear driving member 8 (cam bottom), the cam phase detection means 32 detects the first shooting phase shown in Figure 10 and stops the rear driving source 25, entering the travel standby state shown in Figure 11 (state (3) in Figure 10).

Meanwhile, the rear drive auxiliary member 91 is held by the cam surface 23c of the rear cam gear 23. When the leading drive member 7 passes the cam top of the leading cam gear 22 and continues to rotate, the locked portion 7a of the leading drive member 7 engages with the locking portion 9a of the leading locking member 9, causing the leading drive member 7 to stop at the travel start position. After that, after the leading cam gear 22 retreats from the travel range of the leading drive member 7 (cam bottom), the cam phase detection means 31 detects the stop phase and stops the leading drive source 24.

After the lead drive source 24 stops, a predetermined time elapses, and the release member 51 strikes the pushing portion 9b of the lead locking member 9, causing the lead locking member 9 to rotate counterclockwise around the shaft 6c and disengage the locked portion 7a of the lead drive member 7 (state (5) in Figure 10). Then, from the standby state shown in Figure 11, the lead drive member 7 is rapidly rotated counterclockwise around the shaft 6a by the biasing force of the lead drive spring 12. This causes the lead drive pin 7b to rotate the blade arm 4a counterclockwise, causing the lead blade group 4 to open the exposure opening. As the exposure operation continues, when the slit-forming edge 4h of blade 4d of the lead blade group 4 retreats below the exposure opening, the lead drive pin 7b abuts against a stop member (not shown), stopping the lead drive member 7. After the time corresponding to the set shutter speed has elapsed, the locking release member 52 strikes the pushing portion 10b of the rear locking member 10, causing the rear locking member 10 to rotate counterclockwise around the shaft 6d. This releases the engagement of the locked portion 8a of the rear drive member 8 (state (6) in Figure 10).

Then, from the standby state shown in FIG. 11, the rear drive member 8 is rapidly rotated counterclockwise around the shaft 6b by the biasing force of the rear drive spring 13. The rotational speed at this time is slower than when the rear drive member 8 is pushed by the rear drive assist member 91. To minimize uneven exposure, the time-series speed changes of the slit-forming edge 4h and the slit-forming edge 5h are made similar. The operation of the rear drive member 8 causes the rear drive pin 8b to rotate the blade arm 5a counterclockwise. As a result, the rear blade group 5 covers the exposure opening. As the exposure operation continues, when the slit-forming edge 5h of blade 5d of the rear blade group 5 retreats below the exposure opening, the rear drive pin 8b abuts against a stop member (not shown), stopping the rear drive member 8 (FIG. 12). When the rear blade group 5 stops traveling and the image sensor 203 is completely shielded from light, charge readout scanning begins (state (7) in FIG. 10).

A predetermined time after the rear blade group 5 has completed its travel, current is applied to the front drive source 24 in the forward direction (FIG. 10 (8)), causing the front cam gear 22 to rotate counterclockwise around the shaft 26a. A predetermined time after current is applied to the front drive source 24, current is applied to the rear drive source 25 in the forward direction (state (9) in FIG. 10), causing the rear cam gear 23 to rotate counterclockwise around the shaft 26b. Accordingly, the roller 93 of the rear drive auxiliary member 91, which had been held by the cam surface 23c, leaves the rear cam gear 23 and begins to rotate counterclockwise (state (10) in FIG. 10). However, immediately after the rotation begins, the locked portion 91a of the rear drive auxiliary member 91 is locked to the locking portion 10a of the rear locking member 10 (FIG. 13). In other words, the locked portion 91a can be locked by the rear locking member 10, one of the two locking members. This reduces the charge load during the subsequent setting operation compared to when the rear drive auxiliary member 91 is rotated until it hits the shaft 6f.

Furthermore, as shown in the cam diagram in Figure 10 and Figure 14(a), the cam surface 23c of the rear cam gear 23 has a cam top (a first region corresponding to the cam top position) and a region slightly lower than the cam top (a second region lower than the first region). Just before reaching the state shown in Figure 13, the rear drive assist member 91 does not fall directly from the cam top to the locking position, but rather falls from a position slightly lower than the cam top to the locking position. Therefore, compared to when there is no region slightly lower than the cam top, the amount of rotation required for the rear drive assist member 91 to lock is smaller, making it easier for the rear drive assist member 91 to lock with the rear locking member 10.

When current continues to be applied to the leading drive source 24 and the rear drive source 25, the leading drive member 7 comes into contact with the leading cam gear 22 and is rotated clockwise around the shaft 6a against the biasing force of the leading drive spring 12. The rear drive auxiliary member 91 comes into contact with the rear cam gear 23 and is rotated clockwise around the shaft 6b against the biasing force of the rear drive auxiliary spring 92. Next, the rear drive member 8 comes into contact with the rear cam gear 23 and is rotated clockwise around the shaft 6b against the biasing force of the rear drive spring 13.

Meanwhile, the movement of the leading blade group 4 and the trailing blade group 5 at this time is as follows. The leading drive pin 7b of the leading driving member 7 rotates the blade arm 4a clockwise, causing blades 4d, 4e, 4f, and 4g to move upward while reducing their mutual overlap. The rear drive pin 8b of the rear driving member 8 rotates the blade arm 5a clockwise, causing blades 5d, 5e, 5f, and 5g to move upward while increasing their mutual overlap. When the leading driving member 7 passes the cam top of the leading cam gear 22 and continues to rotate, the locked portion 7a of the leading driving member 7 engages with the locking portion 9a of the leading locking member 9, causing the leading driving member 7 to stop at the travel start position. The leading cam gear 22 continues to rotate, but after it retreats from the travel range of the leading drive member 7 (cam bottom), when the cam phase detection means 31 detects the stop phase, power to the leading drive source 24 is stopped.

The rear drive member 8 similarly continues to rotate, passing through the cam top of the rear cam gear 23, until the locked portion 8a of the rear drive member 8 engages with the locking portion 10a of the rear locking member 10, causing the rear drive member 8 to stop at the travel start position. The rear cam gear 23 continues to rotate, but after it retreats from the travel range of the rear drive member 8 (cam bottom), the cam phase detection means 32 detects the stop phase and stops powering the rear drive source 25 (state (11) in Figure 10).

Figure 9 shows the state after the rear curtain setting operation is completed. From here, the leading driving member 7 and leading blade group 4 begin to travel in order to transition to the live view state. The lock-release member 51 shown in Figure 3(a) strikes the pushing portion 9b of the leading locking member 9, causing the leading locking member 9 to rotate counterclockwise around the shaft 6c and disengage the locked portion 7a of the leading driving member 7. The biasing force of the leading drive spring 12 then causes the leading driving member 7 to rapidly rotate counterclockwise around the shaft 6a. This causes the leading drive pin 7b to rotate the blade arm 4a counterclockwise, causing the leading blade group 4 to open the exposure opening. When the slit-forming edge 4h of blade 4d of the leading blade group 4 retracts below the exposure opening, the leading drive pin 7b abuts against a stopping member (not shown), stopping the leading driving member 7. The leading blade group 4 then completes its travel and enters the travel standby state shown in Figures 4(a) and (b).

After the leading blade group 4 has completed its travel, the leading drive source 24 is stopped, and the image sensor 203 begins live view imaging and preparations for capturing the next frame are made (state (12) in Figure 10). Once preparations for capturing the next frame are complete, the system returns to state (1) in Figure 10, and the series of imaging operations from state (1) to state (12) in Figure 10 are repeated.

The shutter device 202 of this embodiment provides a first and second shooting phase (differentiating the first and second shooting phases), making it possible to use two curtain speeds (fast and slow) without using a dedicated actuator. Preferably, the curtain speed is increased in electronic front-curtain shooting mode (second mode), and the curtain speed is adjusted so that the curtain speeds of the front and rear curtains are the same in mechanical front-curtain shooting mode (first mode) (the curtain speed in the second mode is faster than the curtain speed in the first mode). This makes it possible to increase the X-synchronization speed by increasing the curtain speed in electronic front-curtain shooting while taking advantage of the variable travel curve of the electronic front curtain. Therefore, this embodiment can provide a shutter device and image capture device that can change the curtain speed without using a dedicated actuator.

The above describes preferred embodiments of the present invention, but the present invention is not limited to these embodiments, and various modifications and variations are possible within the scope of the invention.

For example, the electronic front-curtain shooting phase, which is the second shooting phase using the rear drive assist member 91, is a later phase than the mechanical front-curtain shooting phase, which is the first shooting phase without using the rear drive assist member 91. This is to eliminate waste in the cam shape, and is not limited to this.

4. Leading blade group (wing group)
5. Rear feather group (feather group)
7. Lead driving member (driving member)
8 rear drive member (drive member)
9 Tip locking member (locking member)
10 Rear locking member (locking member)
22 Lead cam gear (cam gear)
23 Rear cam gear (cam gear)
91 Rear drive auxiliary member (drive auxiliary member)
202 shutter device

Claims (9)

two sets of blades for opening and closing an exposure aperture;
two drive members for driving the two sets of blades between an open position and a closed position of the opening, respectively;
Two cam gears that move the two drive members, respectively;
two locking members capable of locking the two drive members, respectively;
a drive auxiliary member capable of pushing one of the two drive members ,
a first photographing phase , which is a phase of one of the two cam gears in a rotation direction during photographing in a first mode, is made different from a second photographing phase , which is a phase of one of the two cam gears in a rotation direction during photographing in a second mode;
The driving auxiliary member is
In the first photographing phase, one of the two driving members is not pushed,
A shutter device characterized in that, in the second photographing phase, one of the two drive members is pushed . 2. The shutter device according to claim 1, wherein one of the two cam gears has a cam surface having a cam shape that prevents the auxiliary drive member from pushing one of the two drive members in the first photographing phase. 3. The shutter device according to claim 2 , wherein the cam surface has a first region corresponding to a cam top position and a second region lower than the first region. 4. The shutter device according to claim 1 , wherein the auxiliary drive member has a locked portion that can be locked by one of the two locking members. 5. The shutter device according to claim 1, wherein at least one of the two cam gears has phases in the rotation direction during shooting , in the order of a phase corresponding to a shooting standby state, the first shooting phase, and the second shooting phase. 6. The shutter device according to claim 1 , wherein the two cam gears perform a setting operation on the two drive members from a cam bottom position to a cam top position. A shutter device according to any one of claims 1 to 6 ;
an imaging element that photoelectrically converts an optical image formed through an imaging optical system; the first mode is a mode in which exposure is performed using two slit forming portions of each of the two blade sets,
8. The imaging device according to claim 7 , wherein the second mode is a mode in which exposure is performed using an electronic shutter of the imaging device and one of the slit forming portions of the two sets of blades. 8. The image pickup apparatus according to claim 7 , wherein the curtain speed in the second mode is faster than the curtain speed in the first mode.