JP2013029695A - Imaging apparatus and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow safe driving of a mirror member without a risk of malfunction even if the driving of the mirror member is likely to be blocked by a foreign matter intrusion, in a non-mounting state of a lens.SOLUTION: An imaging apparatus has a configuration that allows a lens device to be mounted on a main body for use, and comprises a drive unit for moving a mirror member between a first position on an optical axis and a second position retreated from the optical axis and a control unit thereof. A drive control of a mirror member is capable of switching between a high speed mode for moving the mirror member in high speed through abruptly releasing a spring force, and a quiet sound mode for moving the mirror member in low speed through gradually releasing the spring force by utilizing a driving force of a motor. In a control to move the mirror member to the second position, if it is determined that the lens device is not mounted on the main body of the imaging apparatus (S604), the control unit suspends the use of the second drive mode, and switches to a first drive mode to drive the mirror member (S607).

Description

  The present invention relates to mirror drive control of an imaging apparatus, and more particularly to drive system switching control.

Conventionally, as a mirror driving method of an imaging apparatus, there are a method using a spring (hereinafter referred to as a spring-up method) and a method using a motor (hereinafter referred to as a motor-up method). The spring-up method is used mainly for high-speed mirrors. However, in the case of the spring-up method, the mirror is driven at a high speed, and therefore, a collision sound is large when it collides with the positioning member provided at the up end when the mirror is flipped up. In view of this, a mirror driving device has been proposed that includes a mechanism using a spring-up system and a motor-up system, and that can select a driving speed.
Patent Document 1 discloses a drive system switching mechanism including a mirror-up mechanism using a spring and a mirror-up mechanism using a motor as a mirror raising mechanism. Patent Document 2 discloses a mirror driving device having speed switching means capable of selecting a mirror driving speed.

Japanese Patent Application Laid-Open No. 07-043802 Japanese Patent Laid-Open No. 10-096988

  By the way, in the motor up system, the motor and the mirror are connected. Therefore, if the mirror is pressed down by foreign matter that has entered the mirror box using the motor-up method, an excessive current may continue to flow through the mirror drive motor, or the battery may be damaged. There is. In addition, a fatal failure such as a gear in the drive mechanism may be damaged. In particular, in a single-lens reflex camera system capable of exchanging lenses, there are many cases where photographing operation is possible even when a lens is not attached. In the digital still camera, the user may open the shutter with the lens not attached in order to check dust or the like adhering to the surface of the image sensor or to perform a cleaning operation. In such a situation, there is a high possibility that foreign matter will enter the mirror box and mirror drive will be hindered.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an imaging apparatus that can safely drive a mirror member and a control method thereof without the risk of failure even in a situation where mirror driving may be hindered due to entry of a foreign object without a lens attached. It is.

  In order to solve the above problems, an apparatus according to the present invention includes a lens mount on which a lens unit is mounted, a movable mirror member disposed on the optical axis of an imaging optical system, and the mirror member on the optical axis. Drive means for driving between a first position and a second position retracted from the optical axis, determination means for determining whether or not the lens unit is mounted on the lens mount, and controlling the drive means Control means, and the drive means includes an actuator, and the first drive system or the actuator drives the mirror member from the first position to the second position without being connected to the actuator. The mirror member is driven by a second drive system that is coupled to drive the mirror member from the first position to the second position, and the control means includes the mirror The material is switched between driving with the first driving method and driving with the second driving method, and the determination means determines that the lens unit is not mounted on the lens mount. In this case, the control means prohibits driving of the mirror member by the second driving method and switches to driving of the mirror member by the first driving method.

  According to the present invention, it is possible to drive the mirror member safely without any risk of failure even in a situation where the mirror drive may be hindered due to entry of a foreign object without the lens attached.

FIG. 8 is a block diagram illustrating a configuration example of an imaging device in order to describe an embodiment of the present invention in conjunction with FIGS. It is a disassembled perspective view which shows a quick return mirror unit. It is detail drawing of a drive lever unit and a cam gear. It is explanatory drawing which shows operation | movement at the time of high speed mode to (A) thru | or (C). It is explanatory drawing which shows operation | movement at the time of a quiet mode in (A) thru | or (D). It is a flowchart which shows the operation example at the time of imaging | photography.

Embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram illustrating a configuration example of an imaging apparatus. The imaging apparatus includes a lens unit 300 and a camera body 100.
The lens unit 300 is an interchangeable lens type, and the lens mount 306 that mechanically couples the lens unit 300 to the camera body 100 also has a function of electrically connecting the two. The lens 310 constituting the imaging optical system includes a focus lens and a zoom lens (not shown) that can move along the optical axis (see the broken line optical path OP1). The diaphragm 312 is positioned on the optical axis and adjusts the amount of light. An interface (hereinafter abbreviated as “I / F”) unit 320 is connected to the I / F unit 120 in the camera body 100. The connectors 322 and 122 that electrically connect the lens unit 300 and the camera body 100 transmit and receive control signals, status signals, data signals, and the like between them, and also have a function of supplying various voltages. The aperture control unit 340 controls the aperture 312 in cooperation with the shutter control unit 40 based on the photometry result obtained by the photometry unit 46 described later. The focus control unit 342 drives the focus lens to control the focus adjustment operation, and the zoom control unit 344 drives the zoom lens to control the zooming operation. A lens control unit 350 that controls the entire lens unit 300 is connected to the I / F unit 320 and each control unit.

Next, the configuration of the camera body 100 will be described.
The shutter 12 controls the exposure of the image sensor 13. The light that has entered the lens 310 in the open state of the shutter 12 reaches the image sensor 13 via the aperture 312, lens mounts 306 and 106, and the shutter 12, and a subject image is formed on the imaging surface (pixel array). . At this time, the mirror 130 is in the mirror-up state retracted from the optical path OP1, as indicated by a two-dot chain line. The mirror 130 is a movable mirror member and is located closer to the subject than the image sensor 13. Hereinafter, the first position in the mirror down state located on the optical axis of the imaging optical system is referred to as “down position”, and the second position in the mirror up state retracted from the optical axis is referred to as “up position”. The driving mechanism of the mirror 130 will be described in detail later.

  The image sensor 13 photoelectrically converts the subject image to generate an image signal, and the A / D converter 16 converts the output signal of the image sensor 13 into a digital signal to obtain image data. The timing generation circuit 18 is controlled by the memory control unit 22 and the system control unit 50, and supplies a clock signal and a control signal to the image sensor 13, the A / D converter 16, and the D / A converter 26. The image processing unit 20 performs predetermined pixel interpolation processing and color conversion processing on the image data output from the A / D converter 16 or the image data output from the memory control unit 22. The memory control unit 22 controls the A / D converter 16, the timing generation circuit 18, the image processing unit 20, the image display memory 24, the D / A converter 26, the memory 30, and the compression / decompression circuit 32. The image data output from the A / D converter 16 is written into the image display memory 24 or the memory 30 via the image processing unit 20 or via the image processing unit 20 and the memory control unit 22. The image display memory 24 temporarily stores image data to be displayed on the image display unit 28. The D / A converter 26 accesses the image display memory 24 via the memory control unit 22 and acquires image data. The D / A converter 26 converts the image data into a display image signal (analog signal) and outputs it to the image display unit 28. A liquid crystal display device (for example, TFT-LCD) or the like is used for the image display unit 28. The memory 30 temporarily stores captured still image data, and is also used as a work area of the system control unit 50. The compression / decompression circuit 32 reads the image data stored in the memory 30, performs compression or decompression processing, and stores the processed image data in the memory 30.

  The shutter control unit 40 controls the shutter 12 in cooperation with the aperture control unit 340 that controls the aperture 312 based on the photometry result of the photometry unit 46. The shutter control unit 40 includes a shutter drive unit 40a and a shutter drive motor 40b. The shutter driving unit 40a drives the shutter 12 so as to expose the image sensor 13. The shutter drive motor 40b has a charging function for the shutter 12, and operates to switch between a fixed state in which the shutter drive unit 40a is fixed and a release state in which the shutter drive unit 40a is released. The mirror control unit 41 moves the mirror 130 to the up position (see the two-dot chain line) or the down position (see the solid line) via the drive unit 41a of the mirror drive mechanism. The actuator controlled by the mirror controller 41 is a mirror drive motor (hereinafter simply referred to as drive motor) 41b. Details of the drive control of the mirror 130 will be described later.

  The focus state detection unit 42 detects a focus state related to the imaging optical system. The light that has entered the lens 310 is detected by the light receiving unit of the focus state detection unit 42 via the stop 312, the lens mounts 306 and 106, the mirror 130, and a sub mirror described later. The focus state detection unit 42 outputs the focus state detection result to the system control unit 50. After entering the lens 310, the photometry unit 46 passes through the aperture 312, the lens mounts 306 and 106, the mirrors 130 and 132, and then detects the light incident from the photometry lens (not shown). The photometry unit 46 outputs the detection result of the exposure state to the system control unit 50. The photometry unit 46 also performs EF processing (pre-flash processing) in cooperation with the flash 48. The flash 48 has an AF (autofocus) auxiliary light projecting function and a flash light control function, and emits light at a predetermined timing in accordance with an instruction from the system control unit 50. The mirror 132 further reflects the light beam reflected by the mirror 130 and guides it to the optical viewfinder 104. The optical path OP2 is one optical path branched by the mirror 130 at the down position with respect to the optical path OP1 leading to the image sensor 13.

  The system control unit 50 that generally controls each unit of the camera body 100 includes a determination unit 50a and a control unit 50b. The determination unit 50 a determines whether the set shooting mode and the lens unit 300 are attached to the camera body 100. The control unit 50b outputs a control command to the mirror control unit 41 according to the determination result of the determination unit 50a. The determination unit 50a and the control unit 50b perform processing in accordance with a program that is interpreted and executed by a CPU (central processing unit) that constitutes the system control unit 50. Details thereof will be described later.

  The memory 52 stores constants, variables, programs, and the like for operating the system control unit 50. In accordance with the execution of the program by the system control unit 50, the notification unit 54 presents a message by characters or images on the display device or a voice message by a speaker or the like to the user. The notification unit 54 is disposed at a position that is easily visible on the camera body 100, and a part of the notification unit 54 is also installed in the optical viewfinder 104. The nonvolatile memory 56 is an electrically erasable and recordable memory (such as an EEPROM).

Next, various operation instructions for the system control unit 50 will be described. FIG. 1 illustrates a mode dial 60, a switch unit 62, and an operation unit 70. The mode dial 60 outputs a user operation instruction to the system control unit 50 for shooting modes including modes such as low-speed continuous shooting and high-speed continuous shooting. The switch unit 62 receives two types of instructions according to user operations. When the user presses a shutter release button (not shown), the first switch (denoted as SW1) is turned on in the first stage (for example, half-pressed). In response to this instruction, the system control unit 50 is instructed to start operations such as AF processing, AE processing, and EF processing. Further, the second switch (denoted as SW2) is turned on in the second stage (for example, fully pressed). In response to this instruction, the system control unit 50 is instructed to start the photographing process including the exposure process, the development process, and the recording process. Note that the exposure process is a process of writing the image signal of the image sensor 13 as image data in the memory 30 via the A / D converter 16 and the memory control unit 22. The development process is a calculation process in the image processing unit 20 and the memory control unit 22. The recording process is a process of reading the image data from the memory 30, compressing it by the compression / decompression circuit 32, and writing the image data to the recording medium 200. The recording medium 200 is a memory card, hard disk, or the like, and includes a recording unit 202, an I / F unit 204, and a connector 206. The connector 206 is connected to the I / F unit 90 via the connector 92 of the camera body 100.
The operation unit 70 includes various operation members such as a menu button, a setting button, and a switching button, and outputs an operation instruction signal to the system control unit 50.

Next, the configuration of the mirror control unit 41 will be described in detail with reference to FIGS.
The mirror control unit 41 includes the mirror driving mechanism shown in FIG. FIG. 3 shows details of the mirror drive lever and the cam. FIG. 2 is an exploded perspective view of the quick return mirror unit. FIG. 3A is a side view of the drive lever unit. 3B and 3C are detailed views of the cam gear 401. FIG. 3B is a view when viewed from a direction orthogonal to the rotation shaft 401e of the cam gear 401, and FIG. 3C is a view when viewed from a direction along the rotation shaft 401e of the cam gear 401.

The mirror 130 includes a main mirror 511 and a sub mirror 513. The sub mirror 513 is a movable member for guiding the light from the lens 310 to the focus state detection unit 42, and is fixed to the sub mirror holding member 514. The sub mirror holding member 514 is pivotally supported around a shaft (not shown) and a hole 514a provided on the main mirror holding member 512, and is focused when the main mirror holding member 512 is stopped at the down position. Part of the light reaches the state detection unit 42 from the subject. Further, the sub mirror holding member 514 is driven to the photographing retreat position together with the main mirror holding member 512 when the main mirror holding member 512 is driven to the up position. In the following description, the driving of the mirror 130 means an operation of rotating the shaft part 512a of the main mirror holding member 512 as a center, and the sub mirror holding member 514 is driven in conjunction with this operation.
The driving force of the driving motor 41b is transmitted to the cam gear 401. The rotation of the cam gear 401 causes the mirror charge lever 406 and the mirror drive lever 407 to rotate counterclockwise or clockwise in FIG. 3A around a shaft provided on the outer surface of the mirror box (not shown). Rotate. Thereby, as will be described later, the mirror 130 performs an up operation of moving from the down position to the up position and a down operation of moving from the up position to the down position. In FIG. 3A, the up movement direction of the mirror 130 is the clockwise direction.

  The mirror charge lever 406 is urged counterclockwise by the urging force of the mirror up spring 405 as an urging member. The main mirror holding member 512, which is a mirror receiving plate, is urged in the mirror down operation direction (counterclockwise direction in the figure) by its axis 512c by the urging force of the mirror down spring 408. The mirror drive lever 407 is urged clockwise by the urging force of the mirror drive lever spring 406d.

  A gear portion 401d (see FIG. 3B) is formed on the outer peripheral surface portion of the cam gear 401, but the tooth portion is not shown. A conductive pattern is formed on the circular side surface 401f (see FIG. 2) of the cam gear 401 in order to detect the rotational position. The conductive contact piece contacts the conductive pattern in accordance with the rotational position of the cam gear 401, and a mirror up operation completion signal is input to the system control unit 50 from the conductive contact piece. Thereby, the control part 50b can determine the rotation position of the cam gear 401, and can determine whether the mirror 130 is located in an up position. Therefore, the conductive pattern formed on the circular side surface 401f of the cam gear 401 detects whether the mirror 130 is positioned at the up position. When the operation of the mirror drive mechanism including the cam gear 401 is hindered for some reason, the mirror up operation completion signal is not input to the controller 50b even if the drive motor 41b is energized for a predetermined time. In this case, the control unit 50b determines that the state is abnormal, and stops driving the drive motor 41b.

The control unit 50b has two types of driving methods for the mirror up operation. The first drive method is a spring-up method, and mirror operation by the spring-up method is hereinafter referred to as a high-speed mode. The second driving method is a motor up method, and mirror operation by the motor up method is hereinafter referred to as a silent mode.
In the spring-up method, the mirror 130 is driven at a high speed by abruptly releasing the spring force of the charged mirror-up spring 405. As a result, an operation with improved performance is performed for the continuous shooting frame speed and the release time lag. In FIG. 4, for simplification, the gear portion 401 d and the first cam portion 401 a of the cam gear 401 are omitted as necessary.

FIG. 4A shows a standby state in which the mirror down operation is completed. FIG. 4B shows a state in which the cam gear 401 stops after rotating in the counterclockwise direction at the initial stage of the mirror-up operation. FIG. 4C shows a state where the mirror up operation is completed.
The cam gear 401 is formed with a first cam portion 401a, a tension release cam 401b, and a second cam portion 401c. As shown in FIG. 3C, these cam portions are formed in different ranges over the circumferential direction around the rotation shaft 401e of the cam gear 401, respectively. Regarding the range of the phase angle centered on the rotation shaft 401e, the second cam portion 401c is set narrower than the first cam portion 401a and the tension release cam 401b. The first follower portion 406b of the mirror charge lever 406 and the first cam portion 401a of the cam gear 401 have a positional relationship in which they can contact each other in a direction orthogonal to the rotation shaft 401e of the cam gear 401. Further, the second follower portion 406c of the mirror charge lever 406 and the second cam portion 401c of the cam gear 401 have a positional relationship in which they can contact each other in a direction orthogonal to the rotation shaft 401e of the cam gear 401.

  In the standby state shown in FIG. 4A, the mirror charge lever 406 is urged counterclockwise by the urging force of the mirror up spring 405. However, the first follower portion 406 b provided on the mirror charge lever 406 is in contact with the cam top (the portion where the lift is maximum) of the first cam portion 401 a of the cam gear 401. For this reason, the mirror charge lever 406 is prevented from being driven counterclockwise, and the mirror-down state is maintained.

  The main mirror holding member 512 is positioned in the down position by abutting against a stopper 519 (see FIG. 2) formed on the inner surface of the mirror box (not shown). A shaft 512c is formed integrally with the main mirror holding member 512, and a contact portion 407a of a mirror drive lever 407 is in contact with the shaft 512c from the lower side of the figure. Further, an urging force in the mirror down operation direction acts on the main mirror holding member 512 from the upper side of the figure by the mirror down spring 408 with the shaft portion 512a as the center. Further, the mirror hook 403 that is rotatably connected to the lower end portion of the mirror charge lever 406 has its hook portion 403c urged counterclockwise by the urging force of the mirror hook spring 402, and the mirror drive lever. The engaging portion 407c of 407 is engaged.

The mirror-up operation when the determination unit 50a determines that the high-speed mode by the spring-up method is set will be described with reference to FIG. In the spring-up system, the charged spring force (biasing force) of the mirror-up spring 405 is rapidly released by rotating the first cam portion 401a by the driving force of the driving motor 41b. The mirror 130 can be driven to the up position at high speed by the biasing force of the mirror up spring 405.
When it is determined that the determination unit 50a is in the high speed mode, when the shutter release button is fully pressed and the second switch SW2 of the switch unit 62 is turned on, the control unit 50b transmits the drive signal for the high speed mirror up operation to the drive motor. To 41b. At this time, the control unit 50b performs drive control by full energization with a duty ratio of 100% to the drive motor 41b. Accordingly, the drive motor 41b is driven at a high speed in the first direction, and the cam gear 401 rotates at a high speed in the counterclockwise direction in the figure. Thereafter, the cam gear 401 reaches the phase (rotation angle) corresponding to the up position shown in FIG. 4C through the state shown in FIG. At this time, a completion signal for the mirror up operation is input to the control unit 50b by detecting the conductive pattern provided on the circular side surface 401f of the cam gear 401. Thereby, the drive motor 41b stops.

  When executing the mirror up operation in the high-speed mode, the control unit 50b measures an elapsed time after the drive motor 41b starts driving in the first direction. If the completion signal of the mirror up operation is not input to the control unit 50b even after a predetermined time (for example, about 1 second) has elapsed after the driving of the drive motor 41b is started, the control unit 50b has an abnormality in the mirror drive mechanism. It is determined that it has occurred, and the drive motor 41b is stopped.

  In the standby state of FIG. 4A, the mirror charge lever 406 is urged counterclockwise by the mirror up spring 405. At this time, the cam top of the first cam portion 401 a of the cam gear 401 is in contact with the first follower portion 406 b provided on the mirror charge lever 406. Thus, the mirror charge lever 406 is positioned in the standby state of FIG. 4A against the urging force of the mirror up spring 405. When the drive motor 41b is driven in the first direction, the cam gear 401 rotates at a high speed in the counterclockwise direction from the standby state in FIG. When the cam gear 401 rotates counterclockwise, the first follower portion 406b provided on the mirror charge lever 406 falls to the cam bottom of the first cam portion 401a of the cam gear 401. As a result, the spring force of the charged mirror up spring 405 is released all at once, and the mirror charge lever 406 is driven counterclockwise by the biasing force of the mirror up spring 405 as shown in FIG. The At this time, the mirror drive lever 407 connected to the mirror charge lever 406 via the mirror hook 403 is also driven at high speed in the counterclockwise direction. The contact portion 407a of the mirror drive lever 407 pushes up the shaft 512c of the main mirror holding member 512 at a high speed, and the mirror 130 is driven at a high speed toward the up position. Along with the mirror up operation of the main mirror holding member 512, the sub mirror holding member 514 connected through the hole 514a is also driven to the up position at a high speed.

  4A, the contact between the first follower portion 406b provided on the mirror charge lever 406 and the cam top of the first cam portion 401a of the cam gear 401 is released by the driving force of the drive motor 41b. Is done. The mirror-up operation of the mirror 130 in the high-speed mode is started after the contact between the first follower portion 406b provided on the mirror charge lever 406 and the cam top of the first cam portion 401a of the cam gear 401 is released. The driving force of the driving motor 41b is not a direct driving force that drives the mirror 130 to the up position. The direct driving force for driving the mirror 130 to the up position is only the biasing force of the mirror up spring 405. Therefore, in the mirror up operation of the mirror 130 in the high speed mode, the mirror 130 is disconnected from the drive motor 41b and is driven to the up position without being connected to the cam gear 401 and the drive motor 41b.

As a detailed operation sequence of the mirror up operation in the high speed mode, after the cam gear 401 stops at the phase shown in FIG. 4C, the main mirror holding member 512, that is, the mirror 130 reaches the up position. In the high speed mode, the mirror 130 jumps up by the biasing force of the mirror up spring 405. Since the main mirror holding member 512 that has reached the up position abuts from below on a stopper 515 formed on the inner surface of a mirror box (not shown), the main mirror holding member 512 is positioned at the up position. At this time, since the speed at which the main mirror holding member 512 abuts against the stopper 515 is high, an impact sound is generated at the moment of abutment.
The mirror operation when the high speed mode is determined by the determination unit 50a has been described above. Until the mirror up operation is performed, the second follower unit 406c of the mirror charge lever 406 and the second cam unit 401c of the cam gear 401 are Will not abut.
In the mirror down operation, the cam gear 410 further rotates counterclockwise in FIG. 4, and the mirror hook 403 is rotated while the contact surface 403a of the mirror hook 403 and the tension release cam 401b are in contact. A mirror down operation of the mirror 130 is performed by rotating the mirror drive lever 407 in the mirror down direction by the biasing force of the mirror drive lever spring 406d.

  Next, the mirror-up operation when the determination unit 50a determines that the silent mode by the motor-up method is set will be described with reference to FIG. In the motor up system, the spring force of the mirror up spring 405 is gradually released using the drive force of the drive motor 41b. Thus, by driving the mirror 130 to the up position at a low speed, it is possible to prevent the generation of an impact sound during the mirror up operation. In the mirror up operation of the mirror 130 in the silent mode, the mirror 130 is connected to the drive motor 41b and driven to the up position.

FIG. 5A shows a state in which the driving of the mirror 130 is stopped by the mirror up operation. FIG. 5B shows a state where the cam gear 401 further rotates in the clockwise direction in a state where the mirror up operation is stopped in FIG. FIG. 5C shows a state at the moment when the second cam portion 401c of the cam gear 401 and the second follower portion 406c of the mirror charge lever 406 are separated. FIG. 5D shows a state where the mirror up operation is completed.
When a shutter release button (not shown) is fully pressed and the second switch SW2 of the switch unit 62 is turned on, the control unit 50b outputs a drive signal for a low-speed mirror up operation to the drive motor 41b. The drive motor 41b is driven at a low speed in a second direction that is opposite to the first direction described above. At this time, the control unit 50b performs drive control using a pulse width modulation (PWM) signal (for example, a duty ratio of 50%). As a result, the drive motor 41b is driven in the second direction at a lower speed than in the high speed mode. That is, the drive motor 41b is driven in the second direction by an energization method different from that in the high speed mode. In the mirror up operation, the drive direction of the drive motor 41b is opposite to that in the high speed mode, and the cam gear 401 rotates at a low speed in the clockwise direction of FIG.

Since the state of the drive mechanism in the standby state is the same as that described in the high-speed mode (see FIG. 4A), detailed description thereof is omitted.
When the cam gear 401 starts to rotate in the clockwise direction from the state of FIG. 4A, the mirror charge lever 406 biased by the mirror up spring 405 starts to drive in the mirror up operation direction. In conjunction with this, the mirror drive lever 407 and the mirror hook 403 start driving, and the mirror 130 starts to be driven. Since the drive mechanism has already been described in the high speed mode, a detailed description thereof will be omitted.

  FIG. 5A shows a state where the main mirror holding member 512 is performing the mirror up operation by the biasing force of the mirror up spring 405. The first cam follower portion 406b of the mirror charge lever 406 traces the first cam portion 401a of the cam gear 401 from the standby state shown in FIG. 4A to the state shown in FIG. With the first cam portion 401a of the cam gear 401 and the first cam follower portion 406b of the mirror charge lever 406 in contact with each other, the mirror charge lever 406 rotates counterclockwise, and the main mirror holding member 512 performs a mirror up operation. . In the silent mode, the following operation is performed in order to reduce the impact sound when the mirror is raised. By causing the first cam follower portion 406b of the mirror charge lever 406 to trace the first cam portion 401a of the cam gear 401, the rotational speed of the mirror charge lever 406 due to the urging force of the mirror up spring 405 is slowed down. That is, when the first cam follower portion 406b of the mirror charge lever 406 traces the first cam portion 401a of the cam gear 401, the spring force of the charged mirror up spring 405 is gradually released, and the mirror charge lever 406 rotates slowly. To do. At this time, the mirror down spring 408 pushes down the shaft 512c of the main mirror holding member 512. Since the shaft 512c of the main mirror holding member 512 and the contact portion 407a of the mirror drive lever 407 are in contact, the urging force of the mirror down spring 408 that pushes down the shaft 512c of the main mirror holding member 512 causes the mirror charge lever 406 to move. Rotate clockwise. For this reason, the force for rotating the mirror charge lever 406 counterclockwise and the force for rotating the mirror charge lever 406 clockwise are balanced, and the operation of the main mirror holding member 512 is as shown in FIG. It will stop in the state shown in.

  FIG. 5B shows a state where the cam gear 401 is further rotated in the clockwise direction from the state where the mirror up operation is stopped in FIG. In this state, the second cam portion 401c of the cam gear 401 abuts on the second follower portion 406c of the mirror charge lever 406, thereby rotating the mirror charge lever 406 counterclockwise in the drawing. As a result, the state in which the raising force for rotating the mirror charge lever 406 in the counterclockwise direction and the lowering force for rotating the mirror charge lever 406 in the clockwise direction shown in FIG. The mirror charge lever 406 rotates counterclockwise by the biasing force of the mirror up spring 405 and the force of the cam gear 401 and the drive motor 41b, and the main mirror holding member 512 continues the mirror up operation. During this time, as shown in FIG. 5B, the contact between the first cam follower portion 406b of the mirror charge lever 406 and the first cam portion 401a of the cam gear 401 is released.

FIG. 5C shows a state at the moment when the contact between the second follower portion 406c of the mirror charge lever 406 and the second cam portion 401c of the cam gear 401 is released. Thereafter, in the state shown in FIG. 5D, a mirror up operation completion signal is input to the control unit 50b. When the completion signal of the mirror up operation is input to the control unit 50b, the control unit 50b stops the drive motor 41b. The mirror up operation in the silent mode is completed. The main mirror holding member 512 that has reached the up position is regulated and positioned by abutting against the stopper 515 from below. Since the speed at which the main mirror holding member 512 abuts against the stopper 515 is low, the impact sound at that moment is smaller than that in the high speed mode.
From the state shown in FIG. 5C to the state shown in FIG. 5D, the mirror charge lever 406 is counterclockwise by the urging force of the mirror up spring 405 without the mirror charge lever 406 coming into contact with the cam gear 401. Rotate to. That is, in the state shown in FIG. 5D from the state shown in FIG. 5C, the contact between the first cam follower part 406b and the first cam part 401a is released, and the second cam follower part 406c and the cam gear 401 are in contact with each other. The contact with the two cam portions 401c is also released.

  When executing the mirror up operation in the silent mode, the control unit 50b starts driving the drive motor 41b in the second direction. After that, when the completion signal of the mirror up operation is not input to the control unit 50b even after a predetermined time has elapsed, the control unit 50b determines that an abnormality has occurred in the mirror drive mechanism and stops the drive motor 41b. The length of the predetermined time (threshold) is, for example, about 300 milliseconds, and is a set value that allows for a margin with respect to the time required for normal mirror-up operation. In the mirror up operation by the motor up system, the mirror may be pressed down by a foreign substance or the like entering the mirror box even if the mirror drive mechanism itself is normal. At this time, the controller 50b promptly stops the motor drive in order to prevent a failure of the mirror drive mechanism due to the inhibition of the rotation of the drive motor 41b and the cam gear 401.

In the present embodiment, the second follower portion provided in the mirror charge lever 406 during the mirror up operation in the silent mode by the motor up method from the state of FIG. 5B to the state of FIG. 5C. 406c and the second cam portion 401c of the cam gear 401 are brought into contact with each other. Thereby, in the second half of the mirror up drive, the motor drive that does not depend on the urging force such as a spring is performed, but the region in which the two are brought into contact is not limited to this. For example, the mirror charge lever 406 may be pushed up by bringing them into contact with each other from the mirror-down state to the completion of the mirror-up operation. In this case, in the silent mode, the mirror-up operation is completed only by the pushing-up force by the second cam portion 401c of the cam gear 401, that is, the driving force of the motor, regardless of the force by the mirror-up spring 405. The second driving method includes a mode in which the mirror up operation is performed only by the driving force of the motor and a mode in which the mirror up operation is performed by using the driving force of the motor and a biasing force by a spring or the like.
In the mirror down operation in the silent mode, the drive control of the drive motor 41b is performed so as to rotate the cam gear 401 in the direction opposite to the mirror up operation, that is, in the counterclockwise direction in FIG.

Next, an operation example of the determination unit 50a will be described using the flowchart of FIG.
FIG. 6 is a flowchart illustrating an operation up to the end of shooting when the imaging apparatus receives a shooting instruction.

  In step S601, the system control unit 50 determines whether the first switch SW1 is on. If SW1 is not in the on state (no in S601), the switch detection is repeated. If it is detected that SW1 is turned on (yes in S601), the process proceeds to S602. In step S602, according to an instruction from the system control unit 50, the focus state detection unit 42 performs focus state detection processing, and the photometry unit 46 performs photometry processing. The system control unit 50 that acquired each processing result advances the processing to S603. In S603, the system control unit 50 determines whether or not the second switch SW2 is on. If SW2 is not in the ON state (no in S603), the switch detection is repeated. When the system control unit 50 detects that the second switch SW2 is turned on (yes in S603), the system control unit 50 advances the process to S604.

  In S <b> 604, the determination unit 50 a of the system control unit 50 determines whether or not the lens unit 300 is attached to the lens mount 106 of the camera body 100. The mounted state of the lens unit 300 can be detected by the I / F unit 120. Specifically, the determination unit 50a acquires a detection signal from the state detection unit provided in the connector 122 and detects the mounting state. When the lens unit 300 is not attached to the camera body 100 (“No” in S604), the determination unit 50a prohibits the use of the silent mode by the motor-up method, and proceeds to S607. If the lens unit 300 is attached to the camera body 100 (“Yes” in S604), the process proceeds to S605.

In S <b> 605, the determination unit 50 a determines the mirror driving method in the control unit 50 b from the information on the shooting mode set by the operation unit 70. The relationship between the shooting mode and the mirror driving method is illustrated in Table 1 below.

  In the present embodiment, a single shooting mode, two types of continuous shooting modes, and a live view mode are shown. When the single shooting mode or the low-speed continuous shooting mode is set, the process proceeds to S606, and the silent mode by the motor up method with a low operating sound is selected. When the high-speed continuous shooting mode is set, the process proceeds to S607, and the high-speed mode by the spring-up method that can operate at a high speed although the operation sound is large is selected. Not only the mirror-up operation at the time of shooting but also the timing at which the mirror-up operation is required at times other than the shooting time. For example, there is a transition process to a so-called live view mode in which a real-time image captured by the image processing unit 20 is displayed on the image display unit 28 by driving the mirror 130 to the up position and opening the shutter 12. . As a driving method in this case, as shown in Table 1 above, a silent mode based on a motor-up method with a low operating sound is selected. In the present embodiment, as an example of the mirror driving method, an example of selecting the mirror driving method corresponding to a so-called drive mode such as single shooting, low-speed continuous shooting, and high-speed continuous shooting has been shown regarding the shooting mode. However, the present invention is not limited to this, and for example, the silent shooting mode and the normal shooting mode may be selected as the shooting mode by the operation unit 70, and these may be associated with the mirror driving method.

In S606, the control unit 50b outputs a drive signal to the drive motor 41b according to the motor up method, and drives the drive motor 41b at a low speed in the second direction, which is the opposite direction to that of the spring up method. As a result, a mirror-up operation is performed so that a loud collision sound is not generated, and the process proceeds to S608 after the operation is completed. On the other hand, in S607, the control unit 50b outputs a drive signal to the mirror drive motor 41b according to the spring-up method, and drives the drive motor 41b at a high speed in the first direction that is opposite to the motor-up method. . Thereby, the contact between the first follower portion 406b and the cam top of the first cam portion 401a of the cam gear 401 is released, and the mirror up operation is performed at high speed by the urging force of the mirror up spring 405. In this case, even if a foreign matter enters the drive range of the mirror 130, there is no hindrance to the rotation of the drive motor 41b and the cam gear 401, and the drive mechanism and the like are not damaged. Since the cam gear 401 can rotate to the position shown in FIG. 4C regardless of the presence or absence of foreign matter in the mirror box, the urging force of the mirror up spring 405 continues to act. Therefore, when the foreign matter is removed, the mirror 130 moves to the up position by the biasing force of the mirror up spring 405.
After the mirror up operation is completed in S606 or S607, the process proceeds to S608. In step S <b> 608, the shutter control unit 40 starts running the shutter 12. Based on the exposure control value according to the photometric result in S602, the system control unit 50 performs predetermined timing control. After the travel of the shutter 12 is completed, the process proceeds to S609, and the control unit 50b outputs a drive signal to the drive motor 41b for the mirror down operation. The mirror-down operation is completed, and the above-described series of processing ends.

  In the present embodiment, there is a risk of mechanical failure by switching the mirror driving method in a situation where the mirror up operation may be hindered by a foreign object when the lens unit 300 is not attached to the camera body 100. Can be reduced.

(Other embodiments)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program. It is a process to be executed.

41 mirror control unit 50 system control unit 50a determination unit 50b control unit 100 camera body 106 lens mount 130 mirror 300 lens unit

Claims (4)

A lens mount to which the lens unit is attached;
A movable mirror member disposed on the optical axis of the imaging optical system;
Drive means for driving the mirror member between a first position on the optical axis and a second position retracted from the optical axis;
Determining means for determining whether or not the lens unit is mounted on the lens mount;
Control means for controlling the driving means,
The driving means includes an actuator, and is connected to the first driving system or the actuator to drive the mirror member from the first position to the second position without being connected to the actuator. Driving the mirror member in a second driving method for driving from the first position to the second position;
The control means switches between driving the mirror member with the first driving method or driving with the second driving method,
When the determination unit determines that the lens unit is not mounted on the lens mount, the control unit prohibits the driving of the mirror member by the second driving method, and the first unit An image pickup apparatus that switches to driving of the mirror member by a driving method. The drive means has a biasing member that biases the mirror member to the second position;
When the mirror member is driven from the first position to the second position by the first driving method, the mirror member is moved from the first position to the second position by the urging force of the urging member. Drive
When the mirror member is driven from the first position to the second position by the second driving method, the mirror member is moved to the first position by the driving force of the actuator and the urging force of the urging member. The imaging apparatus according to claim 1, wherein the imaging apparatus is driven to the second position. When the mirror member is driven from the first position to the second position by the first driving method, the driving means drives the actuator in a first direction so that the driving means moves the actuator and the mirror. Release the connection with the member,
When the mirror member is driven from the first position to the second position by the second driving method, the actuator is driven in a second direction that is opposite to the first direction. The imaging apparatus according to claim 2, wherein the driving unit maintains the connection between the actuator and the mirror member. A lens mount to which the lens unit is mounted; a movable mirror member disposed on the optical axis of the imaging optical system; and a second position in which the mirror member is retracted from the optical axis and a first position on the optical axis. Drive means for driving between positions, determination means for determining whether or not the lens unit is mounted on the lens mount, and control means for controlling the drive means, the drive means comprising an actuator A first drive system for driving the mirror member from the first position to the second position without being connected to the actuator, or the mirror member being connected to the actuator from the first position to the first position. The mirror member is driven by a second driving method for driving to two positions, and the control means drives the mirror member by the first driving method or the second driving method. A control method performed by the image pickup device for switching whether to drive the driving system,
The determination unit determines whether the lens unit is mounted on the lens mount;
When it is determined that the lens unit is not mounted on the lens mount, the control unit prohibits driving of the mirror member by the second driving method, and the mirror member by the first driving method. A method for controlling an imaging apparatus, characterized by switching to driving of the imaging apparatus.

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