JP6207332B2 - Imaging device - Google Patents

Description

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

  2. Description of the Related Art Conventionally, an image pickup apparatus using an image sensor uses a shutter device for controlling an optical path through which reflected light from a subject that has passed through a photographing lens reaches the image sensor.

  In Patent Document 1, shooting is performed by a rear curtain composed of a focal plane shutter (hereinafter referred to as a mechanical shutter) and an electronic shutter that performs charge accumulation start scanning of pixels of the image sensor prior to the running of the rear curtain. An electronic front curtain shutter device is used.

  Some imaging apparatuses have a function (hereinafter referred to as live view shooting) of displaying a subject image captured by an image sensor on a display unit such as a liquid crystal display as a finder for observing the subject during shooting. is there.

  In the electronic front curtain shutter device of Patent Document 2, as a member for driving the rear curtain, an operation member that is connected to the rear curtain and urges the shutter opening portion to be in an open state, and the operation member is shuttered at the time of exposure. It has a drive member which drives so that an opening part may be in a closed state. Furthermore, the rear curtain has a locking member for locking the operating member at the position where the exposure is completed, and a charge member which can drive only the driving member to the position where the exposure is started while the operating member is locked. . By having such a configuration, the electronic front curtain shutter device of Patent Document 2 can cope with both photographing methods of normal photographing while looking through the optical viewfinder and live view photographing using a liquid crystal display or the like.

Japanese Patent Laid-Open No. 11-41523 JP 2007-316503 A

  However, in the imaging device disclosed in Patent Document 1, when the driving member is driven to return to the standby state before photographing after exposure, the shutter opening portion is opened. For this reason, it is necessary to drive the driving member after the charge reading of the image sensor is completed, and it is difficult to cope with shooting at a high continuous shooting speed. Further, since the shutter opening is always open in the standby state before photographing, there is a concern that dust or dirt may adhere to the image sensor.

  Since the electronic front curtain shutter device disclosed in Patent Document 2 is a double light-shielding shutter device, the above-described problems can be avoided. However, since a plurality of parts such as a part for driving the rear curtain and a locking part are required, the shutter device has a complicated configuration and a large shutter device. Moreover, the control method of each part for imaging | photography will also become complicated.

  In view of such problems, the present invention can effectively cope with both photographing methods of normal photographing and live view photographing, and has a simple configuration and a small electronic front curtain shutter device. The purpose is to provide.

  An imaging apparatus according to an aspect of the present invention includes a blade group that closes and opens a shutter opening, a blade driving member that drives the blade group, and a direction in which the blade group closes the shutter opening. The urging member that urges the blade driving member and the urging member that rotates in a predetermined direction drive the blade driving member in a direction in which the blade group opens the shutter opening to charge the urging member. An imaging device having a charging member that performs the above operation and an electromagnetic holding unit that holds the blade driving member in a state in which the blade group opens the shutter opening by magnetic force. Changes in the order of the first state, the second state, and the third state, and the first state is a state in which the blade group closes the shutter opening by the urging force of the urging member, The second In the state, the charge member rotates from the first state, so that the charge member drives the blade driving member, the urging member is charged, and the blade group opens the shutter opening. In the third state, the electromagnetic holding means holds the blade driving member in a state where the biasing member is charged, and the charging member rotates from the second state, The charging member and the blade driving member are released from contact with each other.

  According to the present invention, it is possible to provide an image pickup apparatus that can effectively cope with both shooting methods of normal shooting and live view shooting and has a simple configuration and a small electronic front curtain shutter device. .

It is a center sectional view of a camera system concerning an embodiment of the present invention. It is a disassembled perspective view of a focal plane shutter. It is a figure which shows the vicinity of a blade drive member and a cam gear. It is a figure which shows the operation timing of each component. It is a figure which shows the standby state before a release. It is a figure which shows the charge start of the blade drive spring performed via a blade drive member. It is a figure which shows the lock release start of the down position holding | maintenance of a mirror drive lever. It is a figure which shows the completion of charge of a blade | wing drive spring, and the mirror completion completion state. It is a figure which shows a set cancellation | release state. It is a figure which shows during blade | wing driving | running | working. It is a figure which shows a blade travel completion state. It is a figure which shows a mirror down start state. It is a figure which shows the operation timing of each component.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same members are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a central sectional view of a camera system according to an embodiment of the present invention. The camera system includes a digital single-lens reflex camera body (hereinafter simply referred to as a camera body) 1 and an interchangeable lens 5.

  The interchangeable lens 5 that can be attached to and detached from the camera body 1 is fixed by a mount portion 11 on the camera body 1 side and a mount portion 51 on the interchangeable lens 5 side. When the interchangeable lens 5 is attached to the camera body 1, the contact portion 12 of the camera body 1 and the contact portion 52 of the interchangeable lens 5 come into contact with each other. Thereby, electrical connection is made, and the camera body 1 detects that the interchangeable lens 5 is attached. Further, power supply from the camera body 1 to the interchangeable lens 5 and communication for controlling the interchangeable lens 5 are performed via these contact portions.

  The light beam that has passed through the photographing lens (imaging optical system) 53 of the interchangeable lens 5 enters the main mirror (mirror member) 13 of the camera body 1. The main mirror 13 is fixed to the main mirror holding frame 16 and is rotatably attached to a mirror box (not shown) by a rotating shaft portion 13a. The main mirror 13 is a down position that is held at an angle of 45 ° with respect to the photographic optical axis in order to guide the photographic light beam in the direction of the pentaprism 9, and a position that is retracted from the photographic light beam in order to guide it in the direction of the image sensor 23. It rotates between the up position held by the.

  The main mirror 13 is a half mirror, and the light beam transmitted through the main mirror 13 is reflected downward by the sub mirror 14 and guided to the focus detection unit 15. The sub mirror 14 is fixed to the sub mirror holding frame 17. The sub mirror holding frame 17 is rotatably attached to the main mirror holding frame 16 by a hinge shaft (not shown). The focus detection unit 15 detects a defocus amount of the photographing lens 53 and calculates a lens driving amount for bringing the photographing lens 53 into a focused state. Then, when the calculated lens driving amount is transmitted to the interchangeable lens 5 via the contact portion 12 and the contact portion 52, the interchangeable lens 5 controls a motor (not shown), and the focus lens which is a part of the photographing lens 53 is controlled. The focus is adjusted by moving it.

  The light beam that has passed through the photographing lens 53 is reflected by the main mirror 13 and guided to the viewfinder. The light beam guided to the finder by the main mirror 13 forms a subject image on the focus plate 18. The user is configured to observe the subject image on the focusing screen 18 via the pentaprism 9 and the eyepiece lens 20.

  A focal plane shutter 10 is disposed behind the sub mirror 14. An optical low-pass filter 21 is disposed behind the focal plane shutter 10. At the time of shooting, the light beam that has passed through the optical low-pass filter 21 enters the image sensor 23. The image sensor 23 accumulates the received light as electric charges, and performs an exposure start operation for photographing by charge accumulation start scanning (hereinafter referred to as electronic front curtain travel). The image sensor holder 22 is fixed to the housing of the camera body 1 by screws (not shown) and holds the image sensor 23. The cover member 24 protects the image sensor 23. The rubber member 25 holds the optical low-pass filter 21 and seals between the optical low-pass filter 21 and the image sensor 23.

  FIG. 2 is an exploded perspective view of the focal plane shutter 10. 2A is an exploded perspective view seen from the subject side, FIG. 2B is an exploded perspective view seen from the user side, and FIG. 2C is a partially exploded perspective view.

  A shutter opening 101 a is formed at the center of the shutter base plate 101. A blade driving member 111, a blade operating member 115, and a ratchet 116 are rotatably attached to a shaft 101b provided on the shutter base plate 101. Therefore, the blade driving member 111 and the blade operating member 115 can rotate with respect to the shaft 101 b of the shutter base plate 101. As shown in FIG. 2 (c), a blade drive spring (biasing member) 114, which is a torsion spring, is disposed between the ratchet 116 and the blade drive member 111. The blade drive member 111 is shown in FIG. 2 (c). It is urged clockwise. A cam gear 122 is rotatably attached to a shaft 101 c provided on the shutter base plate 101. A buffer member 103 formed in a half-moon shape with a material such as rubber is fixed to an upper portion of an arc-shaped hole 101 d formed in the shutter base plate 101.

  The auxiliary ground plate 131 is attached to the shafts 101b and 101c. A photo sensor 132 is attached to the auxiliary base plate 131. The photo sensor 132 detects the rotational position of the blade driving member 111 by being shielded from light by the light shielding portion 111 b provided on the blade driving member 111. A mirror drive lever 136 is rotatably attached to a shaft 131 a provided on the auxiliary base plate 131. The screw 137 is fixed to the tip of the shaft 131a so that the mirror drive lever 136 does not fall off the shaft 131a.

  In addition, a yoke 133 and a coil 134 are fixed to the auxiliary ground plate 131 with screws 135. The yoke 133 and the coil 134 constitute electromagnetic holding means, and a magnetic force is generated in the yoke 133 by applying a voltage to the coil 134. When a voltage is applied to the coil 134, the armature 112 provided on the yoke 133 and the blade driving member 111 is attracted by a magnetic force.

  The mirror drive lever 136 is provided with a cam follower 136a and a contact portion 136b that contacts the main mirror drive pin 13b. The mirror drive spring 139 is attached to the mirror drive lever 136, and biases the mirror drive lever 136 in the clockwise direction, that is, in the upward direction in FIG. Further, one end of the main mirror biasing spring 107 is attached to the mirror driving lever 136, and the other end is attached to the rotating shaft portion 13a of the main mirror 13, and the main mirror 13 is counterclockwise in FIG. That is, it is biased downward.

  A flexible printed circuit board (hereinafter simply referred to as an FPC) 138 is connected to the coil 134 and the photosensor 132 through a contact portion 138 a fixed to the auxiliary base plate 131. Further, the rotational position of the cam gear 122 is detected by using the contact portion 138 b fixed to the shutter base plate 101 and the phase contact piece 123 provided on the shutter base plate 101 side of the cam gear 122.

  A cover plate 102 is fixed to the user side of the shutter base plate 101. An opening 102 a is provided at a position substantially coincident with a shutter opening 101 a formed in the shutter base plate 101 at the center of the cover plate 102. A blade chamber in which the rear blade group is arranged is formed between the shutter base plate 101 and the cover plate 102. By making the rear blade group open and closed in the two openings, the light flux passing through the shutter can be reduced. Restricted.

  The rear blade group includes a first blade 141, a second blade 142, a main arm 143, and a sub arm 144.

  The first blade 141 and the second blade 142 are made of polyethylene terephthalate containing a black paint. The first blade 141 and the second blade 142 are rotatably attached to the main arm 143 and the sub arm 144 by pins 145 to form a parallel link.

  The main arm 143 is rotatably attached to a shaft 101e provided on the shutter base plate 101. Further, the main arm 143 is formed with a hole 143a for engaging with an engaging portion 111a provided in the blade driving member 111.

  The sub arm 144 is rotatably attached to a shaft 101 f provided on the shutter base plate 101. Further, a blade return spring 146 is attached to the sub arm 144 in the clockwise direction in FIG. Note that the urging force of the blade return spring 146 is set to be weaker than the urging force of the blade driving spring 114.

  The blade cushioning member 104 is fixed to a rectangular mounting portion 101g provided on the shutter base plate 101, and functions as a stopper member when the rear blade group transitions to the superimposed state. The blade cushioning member 104 is made of a rubber material such as chloroprene rubber, butyl rubber, polyurethane rubber, or silicon rubber, or a material that absorbs an impact such as an elastomer. The periphery of the blade cushioning member 104 is covered with a cover member made of a material having better wear resistance than the blade cushioning member 104 such as metal or plastic.

  FIG. 3 is a view showing the vicinity of the blade driving member 111 and the cam gear 122.

  The cam gear 122 is provided with a mirror cam (second cam member) 122a, a shutter cam (first cam member) 122b, and a gear 122c. The cam gear 122 functions as a charge member.

  The cam gear 122 is transmitted from the motor 147 having an output shaft in the same direction as the shaft 101b of the shutter base plate 101 to the gear 122c via a plurality of reduction gear trains 148 having a rotation axis in the same direction as the shaft 101b of the shutter base plate 101. It rotates in one direction by the driving force. The motor 147, the reduction gear train 148, and the cam gear 122 have the same rotating shaft direction and are connected by gear connection, so that transmission efficiency from input to output is good.

  The mirror cam 122a performs charging and releasing operations of the mirror driving spring 139 via the mirror driving lever 136. When the mirror cam 122a comes into contact with the cam follower 136a and the cam gear 122 rotates in this state, the cam follower 136a slides on the cam surface formed on the mirror cam 122a, and the mirror drive spring 139 is charged. Therefore, the main mirror 13 is rotated between the up position and the down position by the reciprocal rotation of the mirror drive lever 136.

  The shutter cam 122 b performs charging and releasing operation of the blade driving spring 114 via the blade driving member 111. When the shutter cam 122b contacts the roller 113 pivotally supported by the blade driving member 111 and the cam gear 122 rotates in this state, the roller 113 slides on the cam surface formed on the shutter cam 122b, and the blade driving spring 114 is charged. The Therefore, as the blade driving member 111 reciprocates, the rear blade group is in a deployed state and a superimposed state.

  The shutter cam 122b is provided closer to the shutter base plate 101 in the direction of the photographing optical axis 149 than the mirror cam 122a. Thereby, the mirror drive lever 136 and the mirror cam 122a can be easily brought into contact with each other, and the shape of the cam gear 122 can be easily formed.

  Next, the operation of each component will be described. FIG. 4 shows the operation timing of each component. In addition, the states (1) to (13) shown in FIG. 4 correspond to each operation state described later.

First, the case of the normal shooting mode will be described.
(1) Standby State FIG. 5 is a diagram illustrating a standby state before release. FIG. 5A is a view from the subject side, and FIG. 5B is a view from the user side.

  The cam gear 122 is stopped at the position shown in the drawing. The roller 113 pivotally supported by the blade driving member 111 is in a state where the contact of the cam gear 122 with the shutter cam 122b is released.

  The blade driving member 111 is urged counterclockwise in FIG. 5A by the urging force of the blade driving spring 114, and the engagement portion 111 a of the blade driving member 111 has an arc-shaped hole 101 d of the shutter base plate 101. It is in the state which contact | abutted to the buffer member 103 of the upper part.

  At this time, the rear blade group connected to the engaging portion 111a of the blade driving member 111 is in a developed state in which the shutter opening 101a of the shutter base plate 101 and the opening 102a of the cover plate 102 are closed. Further, the power supply to the coil 134 is cut off.

  The mirror drive lever 136 is held in the down position by the cam follower 136 a coming into contact with the cam top portion of the mirror cam 122 a of the cam gear 122 by the biasing force of the mirror drive spring 139. The main mirror 13 is urged in the down direction by the main mirror urging spring 107, abuts against a stopper (not shown), and is held at the down position. There is a gap between the rotating shaft portion 13a of the main mirror and the contact portion 136b of the mirror drive lever 136. Therefore, even if an error occurs in the position of the mirror driving lever 136, the position of the main mirror 13 is held at a correct position by a stopper (not shown), and the light beam that has passed through the photographing lens of the camera is guided to the pentaprism 9 by the main mirror 13. .

  When the photographing operation starts, the motor 147 is energized, the cam gear 122 is rotated via the reduction gear train 148, and the state is changed to “(2) blade driving member charge start state”.

As described above, the state described above is the first state, and the shutter cam 122b and the blade driving member 111 are released from contact with each other, and the energization of the coil 134 is cut off. Further, the mirror cam 122a and the mirror drive lever 136 are in contact with each other.
(2) Blade Driving Member Charging Start State FIG. 6 is a diagram illustrating the charging start of the blade driving spring 114 performed via the blade driving member 111. 6A is a view as seen from the subject side, and FIG. 6B is a view as seen from the user side. Note that portions that have changed since the standby state before the release will be described, and descriptions of portions that have not changed will be omitted.

  As the cam gear 122 rotates, the shutter cam 122 b comes into contact with the roller 113 that is pivotally supported by the blade driving member 111. The blade driving member 111 starts to rotate counterclockwise around the shaft 101 b formed on the shutter base plate 101 in FIG. 6A against the urging force of the blade driving spring 114.

Further, when energization to the motor 147 is continued and the cam gear 122 is rotated via the reduction gear train 148, the state transits to “(3) Mirror drive lever lock release state”.
(3) Mirror Drive Lever Lock Release Start State FIG. 7 is a diagram showing the lock release start of holding the mirror drive lever 136 in the down position. FIG. 7A is a view from the subject side, and FIG. 7B is a view from the user side.

  As the cam gear 122 rotates, the contact between the cam follower 136a of the mirror drive lever 136 and the cam top surface of the mirror cam 122a of the cam gear 122 starts to be released. The mirror drive lever 136 starts to rotate clockwise around the shaft 131a of the auxiliary base plate 131 in FIG. 7A by the biasing force of the mirror drive spring 139.

  The shutter cam 122b of the cam gear 122 is in contact with the roller 113 pivotally supported by the blade driving member 111, and the blade driving member 111 is rotated counterclockwise in FIG. 7A compared to the state in which the blade driving member charging is started. It has become. At this time, the rear blade group is in the process of transitioning to a state of being superimposed on the shutter opening 101a of the shutter base plate 101 and the lower side of the opening 102a of the cover plate 102.

  At the time of shooting using a strobe, photometric operation is performed during the transition from “(1) standby state” or “(2) blade drive member charge start state” to “(3) mirror drive lever unlocked state”. . Preliminary light is emitted with a strobe (not shown), and the light beam reflected by the subject and passed through the camera's taking lens is guided to a photometric sensor (not shown) provided in the vicinity of the viewfinder by the main mirror 13 in a mirror-down state. Done. Thereby, the influence on the release time lag by photometry can be suppressed.

Further, energization of the motor 147 is continued, the cam gear 122 is rotated via the reduction gear train 148, and a transition is made to “(4) contact state between the mirror drive lever and the main mirror”.
(4) Contact state between the mirror drive lever and the main mirror After the mirror drive lever 136 rotates by a predetermined amount, the contact portion 136b of the mirror drive lever 136 contacts the main mirror drive pin 13b, and the main mirror 13 rises. start.

Further, energization of the motor 147 is continued, the cam gear 122 is rotated via the reduction gear train 148, and a transition is made to “(5) blade drive member charge completion state and mirror up completion state”.
(5) Blade Driving Member Charging Completion State and Mirror Up Completion State FIG. 8 is a diagram showing the charging completion and mirror up completion state of the blade driving spring 114 performed via the blade driving member 111. FIG. 8A is a view from the subject side, and FIG. 8B is a view from the user side.

  As the cam gear 122 rotates, the roller 113 pivotally supported by the blade driving member 111 reaches the cam top portion of the shutter cam 122b of the cam gear 122. At this time, the blade driving member 111 is held in a state where the blade driving spring 114 is charged. The rear blade group is superimposed on the shutter opening 101a of the shutter base plate 101 and the opening 102a of the cover plate 102. When the transition of the rear blade group from the deployed state to the superimposed state is completed, the blade cushioning member 104 suppresses deformation that occurs in the rear blade group due to inertia. Further, the armature 112 provided on the blade driving member 111 and the yoke 133 are in contact with each other.

  The main mirror 13 comes into contact with a stopper (not shown), stops after bouncing for a predetermined time, and accordingly, the mirror drive lever 136 stops at the up position. At this time, the main mirror 13 is in a mirror-up state, and the rear blade group is in a superimposed state in which the shutter opening 101a of the shutter base plate 101 and the opening 102a of the cover plate 102 are opened.

  In this state, when the control of stopping the rotation of the motor 147 is performed by short-circuiting the circuit of the motor 147, each component is stopped, and a live view shooting is possible. Details of the operation when performing live view shooting will be described later. Note that this stop operation is not performed in the normal shooting mode when looking through the viewfinder.

  Further, energization of the motor 147 is continued, the cam gear 122 is rotated via the reduction gear train 148, and a transition is made to “(6) coil energization start state”.

  At the time of transition from “(5) blade drive member charge completion state and mirror up completion state” to “(6) coil energization start state”, the voltage is decreased with respect to the energization of the motor 147 and the rotation speed of the cam gear 122 is temporarily increased. You may slow down.

The state described above is the second state, and the shutter cam 122b and the blade driving member 111 are in contact with each other. In addition, the mirror cam 122a and the mirror drive lever 136 are in a released state.
(6) Coil energization start state In the state where the roller 113 pivotally supported by the blade driving member 111 is in contact with the cam top portion of the shutter cam 122b of the cam gear 122, energization to the coil 134 is started and the magnetic force is applied to the yoke 133. The yoke 133 and the armature 112 are brought into the suction state by being generated.

  When the rotational speed of the cam gear 122 is reduced in “(5) blade driving member charge completion state and mirror up completion state”, the vibration to the armature 112 due to the rotation of the cam gear 122 decreases. In this state, the contact surfaces of both components are sucked, so that the suction state is more stable.

  Further, energization of the motor 147 is continued, the cam gear 122 is rotated via the reduction gear train 148, and a transition is made to “(7) set release state”.

When the rotational speed of the cam gear 122 is decelerated in the above-mentioned “(5) blade drive member charge completion state and mirror up completion state”, the voltage is returned to the normal voltage with respect to energization to the motor 147. The rotational speed of the cam gear 122 is returned.
(7) Set Release State FIG. 9 is a diagram showing a set release state of the blade driving member 111. FIG. 9A is a diagram viewed from the subject side, and FIG. 9B is a diagram viewed from the user side.

  As the cam gear 122 rotates, the roller 113 pivotally supported by the blade driving member 111 moves away from the cam top portion of the shutter cam 122b of the cam gear 122. That is, the contact between the blade driving member 111 and the cam gear 122 is released.

  Since energization to the coil 134 is continued, the yoke 133 and the armature 112 are kept in the attracted state. That is, the rear blade group is held in a superimposed state, and the shutter opening 101a of the shutter base plate 101 and the opening 102a of the cover plate 102 are both open.

  In this state, when the circuit of the motor 147 is short-circuited and control for stopping the rotation of the motor 147 is performed, each component stops.

  The state described above is the third state, in which the shutter cam 122b and the blade driving member 111 are released from contact and the coil 134 is energized. Further, the mirror cam 122a and the mirror drive lever 136 are in contact with each other.

Next, an electronic front curtain travel is performed by the image sensor 23, and an exposure start operation for photographing is performed. The time from the start of shooting until the electronic front curtain travel is the release time lag. After starting the electronic front curtain travel, the coil 134 is deenergized after a time interval corresponding to the set shutter speed.
(8) Blade Running Start State to Blade Running FIG. 10 is a diagram illustrating blade running. FIG. 10A is a view from the subject side, and FIG. 10B is a view from the user side.

  By shutting off the power supply to the coil 134, the magnetic force generated in the yoke 133 is lost, and the adsorption of the armature 112 and the yoke 133 is released.

  The blade driving member 111 rotates counterclockwise around the shaft 101 b of the shutter base plate 101 in FIG. 10A by the urging force of the blade driving spring 114. The engaging portion 111a of the blade driving member 111 is engaged with the hole 143a of the main arm 143, and the rear blade group travels upward.

After that, the blade driving member 111 further rotates and transits to “(9) blade travel completion state”.
(9) Blade Travel Completion State FIG. 11 is a diagram showing a blade travel completion state. FIG. 11A is a view seen from the subject side, and FIG. 11B is a view seen from the user side.

  The protruding engaging portion 111a of the blade driving member 111 comes into contact with the buffer member 103 above the arc-shaped hole 101d of the shutter base plate 101, and the rear blade group stops. At this time, the rear blade group is in a deployed state, and the shutter opening 101a of the shutter base plate 101 and the opening 102a of the cover plate 102 are both shielded. Thereby, the exposure to the image sensor 23 is completed.

When the photo sensor 132 detects that the blade driving member 111 and the rear blade group are in the blade travel completion state, the motor 147 is energized after a predetermined time, and the cam gear 122 is rotated via the reduction gear train 148, and “(10) Transition to “mirror down start state”.
(10) Mirror Down Start State FIG. 12 is a diagram showing a mirror down start state that is a charge start state of the mirror drive spring 139 performed via the mirror drive lever 136. 12A is a diagram viewed from the subject side, and FIG. 12B is a diagram viewed from the user side.

  Due to the rotation of the cam gear 122, the mirror cam 122a of the cam gear 122 starts to come into contact with the cam follower 136a of the mirror drive lever 136.

  Thereafter, as the cam gear 122 rotates, the mirror cam 122a of the cam gear 122 pushes the cam follower 136a of the mirror drive lever 136 and rotates counterclockwise in FIG. 12A against the urging force of the mirror drive spring 139.

  The main mirror 13 is urged in the down direction by the main mirror urging spring 107, and the counterclockwise in FIG. 12A in a state where the rotating shaft portion 13a of the main mirror 13 and the abutting portion 136b of the mirror driving lever 136 are in contact. Rotate around and descend.

Further, energization of the motor 147 is continued, the cam gear 122 is rotated via the reduction gear train 148, and the transition is made to “(11) Start of charge reading of image pickup device”.
(11) Start of charge reading of image pickup device Charge read of the image pickup device 23 is started after a predetermined time of the electronic front curtain traveling.

Further, energization of the motor 147 is continued, the cam gear 122 is rotated via the reduction gear train 148, and a transition is made to “(12) mirror down state”.
(12) Mirror Down Completion State The cam follower 136a of the mirror drive lever 136 reaches the cam top portion of the mirror cam 122a of the cam gear 122, and the mirror drive lever 136 is held in the down position. The mirror drive spring 139 is held in a charged state via the mirror drive lever 136.

  Since the main mirror 13 is biased in the down direction by the main mirror biasing spring 107 provided on the mirror drive lever 136, the main mirror 13 abuts against a stopper (not shown) and stops at the mirror down position.

In this state, if the circuit of the motor 147 is short-circuited and the control for stopping the rotation of the motor 147 is performed, each component stops and becomes the same state as “(1) standby state”.
(13) Completion of charge reading of image pickup device The charge reading of the image pickup device 23 is completed. When the release instruction operation is continued after the completion of the charge reading, continuous shooting is performed by repeatedly performing the operations from “(1) standby state” to “(13) completion of charge reading of the image sensor”.

  As described above, the blade drive spring 114 is charged by the shutter cam 122b contacting and pressing the roller 113 pivotally supported by the blade drive member 111 by the rotation of the cam gear 122 before exposure to the image sensor 23.

  After exposure, the mirror cam 122 a is brought into contact with the cam follower 136 a of the mirror drive lever 136 by the rotation of the cam gear 122, thereby charging the mirror drive spring 139.

  Thereby, the charge load can be distributed before and after the exposure, and the peak value of the current consumption can be suppressed.

Next, with reference to FIG. 13, the operation of each component when performing live view shooting in which a subject image is displayed in real time on a display unit provided on the back surface of the camera body 1 will be described.
(1 ′) Standby State The state of each component is the same as “(1) Standby state” described with reference to FIG. However, instead of the release operation, when the live view mode is selected by a dial or button (not shown), the transition to “(2) blade drive member charge start state” is different.

Since “(2) blade drive member charge start state” to “(4) contact state between mirror drive lever and main mirror” are the same as those already described with reference to FIGS. Is omitted.
(5 ′) Blade drive member charge completion state and mirror up completion state The state of each component has already been described with reference to FIG. 8. “(5) Blade drive member charge completion state and mirror up completion state” Is the same.

  As described in “(5) Blade driving member charge completion state and mirror up completion state”, the circuit of the motor 147 is short-circuited, and the control to stop the rotation of the motor 147 is performed to stop each component.

  At this time, both the shutter opening 101 a of the shutter base plate 101 and the opening 102 a of the cover plate 102 are open, and the light flux from the interchangeable lens 5 reaches the image sensor 23. When an image formed on the image sensor 23 is displayed on a liquid crystal display device (not shown) provided on the back surface of the camera body 1, a so-called live view state is obtained.

In this live view state, the roller 113 pivotally supported by the blade driving member 111 is in contact with the cam top portion of the shutter cam 122b of the cam gear 122, so that the rear blade group does not travel even when the power to the coil 134 is cut off. . Therefore, it is possible to keep the live view state in a state where the power supply to the coil 134 is cut off, and it is possible to reduce power consumption. It is also possible to take a moving image in this state.
(6 ′) Coil energization start state When the release instruction operation is started, energization of the coil 134 is started, and a magnetic force is generated in the yoke 133 to bring the yoke 133 and the armature 112 into an attracting state.

  At the same time, the motor 147 is energized, the cam gear 122 is rotated via the reduction gear train 148, and each component changes to “(7) set start state”.

  Since “(7) Set release state” to “(13) Image sensor charge read completion” are the same as those already described with reference to FIGS. 9 to 12, detailed description thereof will be omitted.

  When the release instruction operation is continued after returning to “(1 ′) standby state”, as described above, from “(1 ′) standby state” to “(13) Charge reading completion of image sensor” Continuous shooting is performed by repeating the above operations.

  In addition, after returning to “(1 ′) standby state”, when the release instruction operation is completed and the live view mode is continued, “(2) blade operating member release state” to “(5 ') Transition to “blade drive member charge completion state and mirror up completion state”. That is, the live view state is entered again.

As described above, according to the configuration and operation timing of each component of the present invention, it is possible to effectively support both the normal shooting using the finder and the live view shooting that displays the subject image on the liquid crystal as needed. Thus, it is possible to provide an image pickup apparatus that does not require a plurality of parts necessary for a conventional double light-shielding electronic front curtain shutter device, has a simple configuration of each component, and includes a small electronic front curtain shutter device. .

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  For example, in the present embodiment, the mirror drive system is described as being provided in the focal plane shutter, but a configuration of a mirror drive system independent of the shutter provided in the camera internal structural member may be used.

101a Shutter opening 111 Blade driving member 112 Armature 114 Blade driving spring (biasing member)
122 Cam gear (charge member)
133 Yoke 141 First blade 142 Second blade 143 Main arm 144 Sub arm

Claims (9)

A group of blades for closing and opening the shutter opening;
A blade driving member for driving the blade group;
A biasing member that biases the blade driving member in a direction in which the blade group closes the shutter opening;
A charging member that charges the biasing member by driving the blade driving member in a direction in which the blade group opens the shutter opening by rotating in a predetermined direction;
An electromagnetic holding means for holding the blade driving member in a state in which the blade group opens the shutter opening by magnetic force,
When starting the shooting operation, the imaging device changes in the order of the first state, the second state, and the third state,
The first state is a state in which the blade group closes the shutter opening by the urging force of the urging member,
In the second state, when the charge member rotates from the first state, the charge member drives the blade driving member, the urging member is charged, and the blade group opens the shutter opening. The part is open,
In the third state, the electromagnetic holding means holds the blade driving member in a state where the biasing member is charged, and the charge member rotates from the second state. An imaging apparatus, wherein the contact with the blade driving member is released. An image sensor that accumulates received light as a charge;
A display unit that displays a captured subject image on the image sensor;
The imaging device
When a live view mode in which a subject image from the image sensor is displayed on the display unit in real time is selected, the imaging device changes from the first state to the second state,
The imaging apparatus according to claim 1, wherein when imaging is performed in the live view mode, the imaging apparatus changes in the order of the second state, the third state, and the first state. When the shooting operation starts, the charge member rotates at a first rotation speed,
When the imaging device changes from the first state to the second state, the charge member rotates at a second rotational speed that is slower than the first rotational speed,
The imaging apparatus according to claim 1, wherein when the electromagnetic holding unit holds the blade driving member, the charge member rotates at the first rotation speed.   The imaging device starts accumulating charges after the imaging device changes to the third state, and after a predetermined time, the holding of the blade driving member by the electromagnetic holding unit is released. The imaging device according to any one of 1 to 3. The imaging device changes from the first state to the second state when an instruction operation relating to the start of the photographing operation is maintained after the charge reading of the imaging element is completed. 5. The imaging device according to any one of items 1 to 4. A mirror member capable of rotating between a mirror-up state in which the photographing light beam is incident and a mirror-down state in which the photographing light beam is retracted;
The mirror member is in the mirror-down state when in the first state, and is in the mirror-up state when in the second and third states;
When the imaging device changes from the first state to the second state, the mirror member rotates from the mirror down state to the mirror up state after the charge member starts charging the blade driving member. The imaging apparatus according to any one of claims 1 to 5, wherein: The charge member includes a first cam member that contacts the blade driving member,
The imaging device according to claim 1, wherein the urging member is charged by sliding the blade driving member on a cam surface formed on the first cam member. apparatus. The charge member includes a second cam member that contacts the mirror member,
The mirror member is rotated from the mirror-up state to the mirror-down state when the mirror member slides on a cam surface formed on the second cam member. The imaging device described. The imaging device according to any one of claims 1 to 8,
An image pickup optical system that makes an image pickup light beam incident on the image pickup apparatus.