JP2009294539A - Mirror drive apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mirror drive apparatus which quickly suppresses vibration caused when a mirror is driven, prevents the increase of cost and reduces the size. <P>SOLUTION: The mirror drive apparatus includes: a mirror unit 4 having a main mirror 5 moving between an approach position for image observation where the main mirror 5 enters the optical path of an imaging optical system, and a retreat position for imaging where the main mirror 5 is retreated from the optical path of the imaging optical system; a mirror drive motor 13a rotationally driving the main mirror 5; a velocity profile storage section 12Ab storing a moving velocity at which the main mirror 5 shifts between the approach position and the retreat position from when the main mirror 5 starts moving to when the main mirror 5 stops, as an angular velocity profile; a mirror drive section 31 detecting a movement angular velocity assumed during driving of the main mirror 5; and an angular velocity instruction section 12Aa controlling the drive motor 13a, based on the angular velocity profile and the detected movement angular velocity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mirror driving device for driving a movable mirror required for subject image observation and focus adjustment in a digital single-lens reflex camera system or the like.

  Conventionally, in a drive system of a digital single-lens reflex camera system, various mechanisms have been proposed that satisfy a desired function of the system by operating a camera using a motor. Therefore, there is an increasing demand for improving the performance of the camera system, such as a demand for improving the high-speed continuous shooting performance for accurately photographing a desired scene. In order to ensure high-speed continuous shooting performance, it is necessary to speed up the mechanism required for shooting and the imaging function that controls it, or to process the output result of the imaging device and save the result in a predetermined storage device There is a need for faster photo development functions.

  In a conventional single-lens reflex camera system to which a quick return mirror (main mirror), which is a normal movable mirror, is applied, the direction of the optical path of the taking lens is set in the viewfinder during shooting preparation (when observing a subject image) and during shooting (exposure). It is necessary to switch between the (viewfinder) side and the image sensor. In the stage of shooting preparation, the light beam that has passed through the lens is focused on the optical finder and the distance measuring sensor, and in the stage of shooting, the beam is focused on the imaging device. Such shortening of the optical path switching time (the time required for stabilization during the switching operation) is an important factor in determining the high-speed continuous shooting performance.

  As a specific factor, there is a reduction in the operation time of the quick return mirror that changes the optical path. For example, when the optical path of the light beam is switched, the quick return mirror collides with a stopper disposed at a mirror up position (shooting start position) or a mirror down position (observation, ranging start position). Mechanical vibrations occur. It is necessary to wait for the mirror up stabilization at this time and shift to the photographing sequence, or shift to the distance measurement sequence after the mirror down stabilization.

  In the mirror drive device for a camera disclosed in Patent Document 1, a mirror-driving cam shape is devised in a mechanism integrated with an actuator and a mirror to suppress a vibration. In such a prior example, the mechanism of the mechanism is devised to reduce the vibration of the mirror and shorten the mirror settling time. Further, in order to perform tuning in the deceleration state, it is necessary to repeat trial manufacture and evaluation of the cam, and the cost of the apparatus is increased by adding mechanical parts.

  In the future, in order to reduce the size of the system while maintaining high performance, it is necessary to apply a drive mechanism in which the motor and mirror are coupled by a gear without using a cam or the like, unlike the conventional mechanism described above. This is also desirable from the viewpoint of preventing bounce due to the collision of the mirror.

  Therefore, a system schematic configuration diagram of FIG. 8 is conceivable as a single-lens reflex camera system employing the above-described control method. A single-lens reflex camera system 80 shown in FIG. 8 is an interchangeable lens mirror that includes a camera body 81 and a photographic lens that can be attached to and detached from the camera body 81 and takes a subject light beam along the optical axis O into the camera body 81 side. It consists of a cylinder 82. The camera body 81 includes a finder unit 83 including a focusing screen, a pentaprism, and an eyepiece, a main mirror (quick return mirror) 84 provided with a sub mirror 84a, and a drive unit such as a reduction gear for driving the mirror 84. A mirror drive motor 87 composed of a DC motor, a shutter unit 88, an image sensor 89 composed of a CCD or the like, and an AD converter (ADC) 90 that performs AD conversion of the image signal as an electric control element, AF sensor 93, a phase difference AF sensor 91, a mirror controller 92, an AF control unit 93 that is an arithmetic circuit for converting to a defocus distance of the photographing lens based on the output of the distance sensor 91, and an output of the AD converter 90 And an image processing unit 94 for obtaining subject image data.

  In the camera system 80, the main mirror 84 is moved directly by a mirror drive motor 87 via a gear or the like without a cam or the like, or a mirror drive lever (not shown) at the time of switching between a finder observation state and a photographing state. It is assumed that the optical path entry position and the optical path retreat position are driven via the. When the main mirror 84 is at the optical path entry position, the subject luminous flux along the optical axis O is reflected toward the finder unit 83, and when the main mirror 84 is at the optical path retracted position, the subject luminous flux is incident on the image sensor 89 side. When the main mirror 84 is at the optical path entry position, a part of the subject light beam is reflected toward the distance measuring sensor 91 by the sub mirror 84a. Note that the optical path entry position or the optical path retract position of the main mirror 84 is positioned by the stoppers 86 and 85.

  When the camera is switched to the viewfinder observation state (ranging state), the main mirror 84 is accelerated from the mirror control unit 92 toward the stopper 86, and stops when it touches. Further, when the camera is switched to the photographing state, the main mirror 84 is accelerated toward the stopper 85 by the mirror control unit 92 and stops when it touches.

  FIG. 9 is a diagram showing changes in motor instruction voltage (in other words, drive voltage, indicated by a solid line) and mirror moving speed (indicated by a broken line) in the mirror drive state in the single-lens reflex camera described above. The motor drive voltage is a voltage waveform for accelerating the mirror drive motor 87 (the drive voltage during acceleration is + Vmax) and decelerating (the drive voltage during deceleration is -Vmax). It corresponds to the output signal 87a. The drive voltage for acceleration / deceleration of the drive motor 87 is changed from acceleration to deceleration when an electric signal 87b indicating a state of arrival at a predetermined position obtained from the photo interrupter (PI) 95 constituting rotation of the output shaft of the drive motor 87 is detected. Can be switched. In this control, the vibration due to the collision with the stoppers 85 and 86 is not settled even at the end of deceleration, and it takes some time for the main mirror 84 to completely stop (the speed becomes zero). As a result, the exposure start operation is performed. Or a delay in the finder observation or a delay in the start of the distance measuring operation.

Therefore, in order to solve this problem by a device for control, in the mirror driving device disclosed in Patent Document 2, an encoder is provided in the mirror driving motor, the current position is acquired from an output signal from the encoder, By performing feedback control that operates the mirror according to a speed profile set in advance according to the position, the collision speed near the stop position is reduced, and the vibration of the mechanical unit is suppressed.
JP-A-7-36104 Japanese Patent No. 2626991

  However, according to the control method of Patent Document 2 described above, position detection must be relied on mechanical parts such as an encoder or a detection LSI, and as a result, there is a concern about an increase in the cost of the apparatus. In addition, it is difficult to cope with downsizing.

  The present invention has been made in order to solve the above-described problems, and is proposed in particular from the viewpoint of speeding up an imaging function that is indispensable for continuous shooting of a single-lens reflex camera having a movable mirror. Another object of the present invention is to provide a mirror driving device that can quickly suppress vibrations that occur during driving of a mirror, that can avoid an increase in cost, and that can be downsized.

  According to a first aspect of the present invention, there is provided a mirror driving device that enters the optical path of an image pickup optical system, and a first position for at least one of subject image observation or focus adjustment and the image pickup optical system. A mirror unit that moves between a second position for taking an image and retracts from the optical path, a drive unit that drives the mirror unit, and a period from when the mirror unit starts moving until it stops In addition, a storage unit that stores a moving speed at which the mirror unit should move between the first position and the second position as a speed profile, and a moving speed assumed during driving of the mirror unit are detected. A speed detection unit; and a control unit that controls the drive unit based on the speed profile and the detected moving speed.

  A mirror driving device according to a second aspect of the present invention is the mirror driving device according to the first aspect, wherein the control unit starts the movement of the mirror unit from the first position or the second position. And a control start unit for starting the control after a predetermined time has elapsed or after passing through a predetermined position.

  A mirror driving device according to a third aspect of the present invention is the mirror driving device according to the first aspect, wherein the control unit is configured to stop the mirror unit at the first position or the second position. It further includes a stop control unit that performs the above control so as to maintain the stop.

  A mirror driving device according to a fourth aspect of the present invention is the mirror driving device according to the first aspect, wherein the speed detecting unit detects the moving speed based on a driving current during driving of the mirror unit. A speed detection control unit is further provided.

  According to the present invention, it is possible to provide a mirror driving device that can quickly suppress vibrations that occur during driving of a mirror, that can avoid an increase in cost, and that can be downsized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a main configuration of a single-lens reflex camera (hereinafter, referred to as a single-lens reflex camera) incorporating the mirror driving device according to the first embodiment of the present invention. FIG. 2 is a block configuration diagram of an angular velocity instruction unit including a velocity detection unit of a mirror driving device built in the single-lens reflex camera of FIG. FIG. 3 is a diagram showing a change in the indicated angular velocity in the single-lens reflex camera of FIG.

  As shown in FIG. 1, the single-lens reflex camera 20 of the first embodiment includes a camera body 1 and an interchangeable lens barrel 2 that can be attached to and detached from the camera body 1.

  An interchangeable lens barrel (hereinafter referred to as a lens barrel) 2 incorporates a photographic lens 2a as a photographic optical system that is driven to be focused by an AF control unit 15 described later. In a state in which the lens barrel 2 is mounted on the camera body 1, the subject luminous flux along the optical axis O, which is the optical axis of the photographing lens 2a, is taken into the camera body 1 side for observation and focusing of the subject image. Measurement of the subject distance (ranging), measurement of subject luminance for exposure control (photometry), and photographing (capturing the imaging signal of the subject) are performed.

  The camera body 1 includes a finder unit 3 including a focusing screen, a pentaprism, an eyepiece, and a photometric sensor unit, a mirror unit, a mirror unit 4 having a rotatable main mirror 5 and a sub mirror 6, and a mirror unit 4 A mirror drive unit 13 that is a drive unit including a reduction gear 13b for rotating the main mirror 5 and a mirror drive motor 13a composed of a DC motor, a shutter unit 9, and an image sensor as an electric control element. A certain CCD 10, an AD converter (ADC) 11 that performs AD conversion of an image pickup signal, a phase difference AF distance sensor 14, and an operation for converting to a defocus distance of the photographing lens based on the output of the distance sensor 14 To obtain subject image data using the AF control unit 15 having a circuit and the output of the AD converter 11 An image processing unit 16, and a system controller 12 including a CPU for controlling the drive control and the respective electrical control elements of the mirror unit 4. The mirror unit 4, the mirror drive unit 13, and the system controller 12 constitute a mirror drive device.

  The system controller 12 controls each of the electric control elements, controls the driving of the mirror driving motor 13a of the mirror driving unit 13, and controls the mirror driving device for rotationally driving the main mirror 5 in a predetermined operation state. It has an angular velocity instruction unit 12Aa and a velocity profile storage unit 12Ab as a unit. The system controller 12 receives the current value detection signal 12Ad of the mirror drive motor 13a.

  The mirror unit 4 includes a main mirror (quick return mirror) 5 that is rotatably supported via a mirror shaft 5a. Further, the mirror unit 4 rotates via a support shaft 6a of a support frame that holds the main mirror 5. A sub-mirror 6 that is movably supported is provided.

  The main mirror 5 is capable of rotating to an approach position that is a first position in the optical path of the subject light beam on the optical axis O and a retreat position that is a second position retracted from the optical path of the subject light beam. . Further, the approach position of the main mirror 5 is positioned by contacting the support frame with the stopper 8, and the retracted position is positioned by contacting the support frame with the stopper 7 (FIG. 1).

  In a state where the main mirror 5 is located at the entry position, the subject light flux along the optical axis O is reflected to the viewfinder unit 3 side by the main mirror 5, and the subject image is observed by the eyepiece. Further, when the main mirror 5 rotates to the entry position, the sub mirror 6 moves in an oblique state to the optical path entry position obliquely provided on the optical axis O in conjunction with the main mirror 5. In this state, a part of the subject light beam transmitted through the main mirror 5 is reflected by the sub mirror 6 and enters the distance measuring sensor 14.

  In a state where the main mirror 5 is retracted to the retracted position, the sub mirror 6 is also retracted from the optical path of the subject luminous flux together with the main mirror 5. Therefore, the subject luminous flux passes through the open shutter unit 9 disposed behind the subject luminous flux and enters the CCD 10, and forms an object image on the photoelectric conversion surface.

  A distance measurement signal of phase difference AF is detected by the subject light beam incident on the distance measurement sensor 14, and focus driving control of the taking lens 2 a of the lens barrel 2 is performed by the AF control unit 15. An imaging signal obtained from the subject image formed on the photoelectric conversion surface of the CCD 10 is AD-converted by the AD converter 11, converted to a video signal by the image processing unit 16, and recorded on the recording medium as photographed image data. Is done.

  The main mirror 5 is driven to be switched from the retracted position to the entrance position where the subject can be observed or the focus can be adjusted when the power switch of the camera is turned on or when imaging is completed. The switching operation is performed quickly in a short time. In response to the first release operation of the camera, distance measurement by the distance measurement sensor 14 is started. Further, the driving of the main mirror 5 from the approach to the retracted position is also quickly performed in a short time when photographing (CCD exposure) is performed in accordance with the second release operation of the camera.

  In this embodiment, the rotation drive of the main mirror 5 to the entry position or the retraction position is performed by the mirror drive of the mirror drive unit 13 by the output signal 12Ac of the angular velocity instruction unit 12Aa under the control of the system controller 12. It is driven by a motor 13a through a reduction gear 13b.

  Between the main mirror 5 and the reduction gear 13b of the drive unit 13, for example, a state in which a fan-shaped gear (not shown) is interposed that is integral with the main mirror 5 and is rotatably supported by the mirror shaft 5a. In this way, it is driven to rotate at the respective rotation positions.

  Here, the configuration of the angular velocity instruction unit 12Aa of the system controller 12 and the mirror drive control operation for rotationally driving the main mirror 5 to each position described above will be described with reference to FIGS.

  FIG. 2 is a block configuration diagram of the angular velocity instruction unit of the system controller, and shows a change with respect to elapsed time of an instruction angular velocity (teacher speed) and an estimated angular velocity value by the angular velocity instruction unit of FIG. The angular velocity is indicated by the mirror rotation angular velocity (ωrad / sec) around the mirror axis 5a of the main mirror 5, and the mirror rotation angular acceleration (αrad / sec) described later is around the mirror axis 5a of the main mirror 5. The rotational angular acceleration of is shown.

  In addition to the camera control unit, the system controller 12 includes an angular velocity instruction unit 12Aa that is a control unit for driving the mirror and a speed profile storage unit 12Ab that is a storage unit. The angular velocity instruction unit 12Aa stores the velocity profile storage unit 12Ab in the speed profile storage unit 12Ab. The mirror drive motor 13a of the mirror drive unit 13 is controlled so that the main mirror 5 is driven at the indicated angular velocity according to the stored angular velocity profile. That is, the rotational angular acceleration α0 of the mirror estimated from the load of the mirror driving system and the torque characteristics of the driving motor during the control operation of the main mirror 3 is estimated by calculation, and the estimated rotational angular acceleration α0 is estimated by the speed indicator. Feedback to 12Aa (FIG. 2). After the main mirror 5 is quickly rotated to a desired position at an angular velocity according to the angular velocity profile, when the main mirror 5 comes into contact with the stopper 7 or 8, the rotation speed is set to zero. A drive voltage signal dv for applying a drive voltage to the mirror drive motor 13a is outputted so as to suppress the occurrence of bounce as much as possible. In this embodiment, the mirror drive motor 13a is a DC motor capable of speed control as described above.

  In the speed profile storage unit 12Ab built in the system controller 12, an instruction angular velocity A (Vmax) for instructing a constant angular velocity of the main mirror 5 in the mirror driving initial period indicated by a change in the instruction angular velocity (solid line) in FIG. An instruction angular speed B (VB) for instructing the speed of the main mirror 5 after the elapse of a predetermined period (T1) is stored. The indicated angular velocity B is given by data that changes so that the velocity becomes zero when the deceleration starts in the middle of the operation (after T2) and abuts against the stopper 7. The indicated angular velocities A (Vmax) and B (VB) in FIG. 2 are both given as digital values.

  The angular velocity instruction unit 12Aa includes a selector 22, a selector 26, a timer 25 that is a control start unit, a 0 sense output unit 28, an A / D converter 29, an accumulation calculation unit 27, a subtractor 23, a D / D The A converter 24 and a sense amplifier 37 that amplifies the detection current value output from the mirror drive unit 31 (FIG. 2).

  The selector 22 is selected from the angular velocity profile data stored in the velocity profile storage unit 12Ab and after the first elapsed time T1 and the designated angular velocity A (Vmax), which is a predetermined designated value instructed at the beginning of driving. The command angular velocity B (VB) is input, and one of the values is output.

  The timer 25 measures the first elapsed time T1 (FIG. 3), and controls the selection operation of the selectors 22 and 26 by its output.

  The A / D converter 29 performs A / D conversion on the voltage signal obtained by amplifying the current value of the mirror driving unit 31 by the sense amplifier 37.

  The cumulative calculation unit 27 is a calculation unit that integrates the digital value of the mirror estimated rotation angular acceleration α0 that is the output of the A / D converter 29 to obtain the mirror estimated rotation angular velocity.

  The selector 26 is inputted with the output value 0 data 28a of the 0-sense output device 28 and the estimated mirror rotation angular velocity data 27a of the accumulator 27, and selects and outputs one of the values.

  The subtracter 23 performs processing for subtracting the output data 26 a of the selector 26 from the output value of the selector 22.

  The D / A converter 24 takes in the indicated angular velocity data that is the output value of the subtracter 23, performs D / A conversion, and outputs a motor drive voltage signal dv. The motor drive voltage signal dv is output to a drive motor drive circuit (not shown) for driving the mirror drive motor 13a shown by the mirror drive unit 31.

  The mirror drive unit 31 in FIG. 2 is a mirror drive unit composed of a mirror drive motor 13a and a mirror unit load, and is schematically represented by a function.

  Specifically, the mirror drive unit 31 includes a resistance element (R) 33 for obtaining the motor current value I (A), a torque constant element (KT) 34 for obtaining the output torque T (Nm), and a mirror drive system load ( Inertia performance ratio) The transmission element 35 based on JM, the counter electromotive force coefficient element (KE) 36 for obtaining the counter electromotive force based on the estimated mirror rotation angular velocity ω 0, and the counter electromotive force value consisting of the motor drive voltage signal dv are subtracted. This is expressed as a subtraction element 32.

  Note that the transmission element 35 based on the mirror drive system load (inertia performance rate) equivalently converts the inertia rates of all the mirror drive systems including the mirror drive motor 13a, the reduction gear 13b, and the mirror unit 4 onto the mirror shaft 5a, and adds them up. Is expressed by an integral element 1 / (s × JM) based on the obtained inertial performance factor JM.

  The sense amplifier 37 is an amplifier that multiplies the detected current value I (A) in the mirror driving unit 31 by the motor torque constant KT and the inertia ratio JM, and outputs a mirror estimated rotational angular acceleration α0. The sense amplifier 37 may not be applied, and after A / D conversion, the digital output value may be multiplied by KT × JM.

  The system controller 12 uses the angular velocity instruction unit 12Aa and the velocity profile storage unit 12Ab having the above-described configuration to control the rotational drive operation of the main mirror 5 to the entry position or the retraction position. The drive control method is executed by the same control. Therefore, hereinafter, the control operation by the system controller 12 from the retracted position to the approach position will be described.

  When the release switch is operated or when an instruction to switch the camera to the finder observation state is issued from the system controller 12 at the end of photographing, the timer 25 starts counting at the angular velocity instruction unit 12Aa, and the selector 22 reads from the velocity profile storage unit 12Ab. Angular velocity data Vmax, which is a constant indicated angular velocity A to be read, is selected and output. From the selector 26, the output 0 data of the 0 sense output unit 28 is selected and output. Accordingly, only the angular velocity data Vmax is output from the subtractor 23, D / A converted by the D / A converter 24, and further, the drive voltage signal dv for driving the mirror drive motor 13a with the angular velocity data Vmax is the mirror drive unit 31. Is output. At the same time, the drive voltage signal dv is also output to the drive motor drive circuit (not shown) via the signal line 12Ac, the drive voltage corresponding to the drive voltage signal dv is applied to the mirror drive motor 13a, and the main mirror 5 enters. The rotation drive is started toward the position.

  A drive voltage signal dv is input to the mirror drive unit 31. The cumulative calculation unit 27 obtains the estimated angular velocity V0 for each elapsed time T. In the initial driving state until the elapsed time T1 when the main mirror 5 approaches the stopper 7, the angular velocity data Vmax of the indicated angular velocity A as described above. Only by this, the drive voltage signal dv is generated and output.

  After that, when the timer 25 reaches the elapsed time T1, the selector 22 selects and outputs the angular velocity data VB of the indicated angular velocity B read from the velocity profile storage unit 12Ab. As shown in FIG. 3, the angular velocity data VB is equal to the indicated angular velocity data Vmax at the elapsed time T1, but enters an area where the mirror gradually decelerates from the elapsed time T2 when the mirror further approaches the stopper and reaches the approach position. Is the indicated angular velocity data that changes so as to be 0 (region RA in FIG. 3).

  After the elapsed time T1 is reached, the selector 26 obtains the estimated rotational angular acceleration α0, which is the output of the sense amplifier 37, after A / D conversion by the A / D converter 29 and integration by the accumulator 27. The estimated rotational angular velocity data 27a (estimated angular velocity data V0) is selected and output. Then, the difference between the data value VB and the estimated angular velocity data 27 a is output as a drive voltage signal dv through the D / A converter 24 in the subtracting unit 23.

  In the state after the elapsed time T1 is reached, the drive voltage by the drive voltage signal dv is such that the difference between the estimated angular velocity data V0 obtained by integrating the estimated rotational angular acceleration α0 and the indicated angular velocity data Vmax is as small as possible. It is applied to the drive motor 13a. This control state is continued until an elapsed time T3 where it is estimated that the main mirror 5 contacts the stopper 7.

  FIG. 3 shows changes in estimated angular velocity data V0 (broken line) obtained by A / D converting the estimated rotational angular acceleration α0.

  The indicated angular velocity data VB is set to 0 at the elapsed time T3 when the main mirror 5 is expected to come into contact with the stopper 7. Therefore, the bounce due to the contact between the main mirror 5 and the stopper 7 is suppressed, and the main mirror 5 can be quickly rotated from the retracted position to the entry position.

  As described above, according to the single-lens reflex camera system 20 of the present embodiment, the main mirror 5 is driven to rotate at a desired rotation speed according to the angular velocity profile stored in the system controller 12, thereby causing the main mirror 5 to move. It is possible to quickly move to the entry position or the retreat position while suppressing the bounce by reducing the impact when contacting the stopper. Accordingly, it is possible to quickly open the shutter to shift to exposure, and to quickly switch to the finder observation state and the distance measurement state. Simultaneous high-speed continuous shooting is also possible. Further, it is not necessary to detect the rotation amount of the mirror drive motor 13a by using the rotation sensor by estimating the rotation speed of the mirror at the time of the rotation drive, and it becomes possible to drive at the desired rotation speed. The structure of the part is simplified, the cost can be reduced, and the size can be reduced.

  The deceleration of the indicated angular velocity data VB shown in FIG. 3 changes linearly with respect to the elapsed time. However, the present invention is not limited to this, and the indicated angular velocity is set so as to decelerate in a curved line. It is also possible.

  Next, the mirror drive device in the single-lens reflex camera of 2nd Embodiment of this invention is demonstrated using FIG.

  FIG. 4 is a block configuration diagram of an angular velocity instruction unit including a velocity detection unit of the mirror driving device of the present embodiment. FIG. 5 is a diagram showing changes in the indicated angular velocity and the estimated angular velocity value with respect to the mirror rotation position in the single-lens reflex camera of the present embodiment.

  The angular velocity instruction unit 12Ba of the mirror driving device according to the present embodiment does not require the timer 25 as compared with the angular velocity instruction unit 12Aa in the first embodiment, and instead of this, the stop control that estimates the mirror movement amount by integrating the angular velocity. A cumulative calculation unit 45 is provided as a unit. The other configurations including the mirror drive unit 31 of the angular velocity instruction unit and the single-lens reflex camera are the same as those in the first embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and different parts will be described below.

  In the angular velocity instruction unit 12Ba of the present embodiment, the estimated angular acceleration α0 that is the output of the sense amplifier 37 of the mirror driving unit 31 is accumulated via the A / D converter 29 as in the case of the first embodiment. And the estimated angular velocity data 47a is calculated by the integration process. The estimated angular velocity data 47a is input to the selector 46. Further, the output of the cumulative calculation unit 47 is input to the cumulative calculation unit 45, where an integration process is performed to obtain estimated movement position (rotation position) data 45a of the main mirror 5. Based on the estimated movement position data, data selection processing of the selector 42 and the selector 46 is performed. This operation replaces the data selection process by the timer 25 in the first embodiment.

  Specifically, when the estimated movement position data 45a of the main mirror 5 calculated by the cumulative calculation unit 45 reaches the mirror position P1 (FIG. 5) approaching the stopper 7, it is stored in the speed profile storage unit 12Bb by the selector 42. The command angular velocity A data Vmax is switched to the command angular velocity B data VB and output. Further, the selector 46 switches the output value 0 of the 0 sense output device 28 to the mirror estimated rotation speed data 47a (estimated angular speed data V0) which is the output of the cumulative calculation unit 47, and outputs the result. Thereafter, as in the case of the first embodiment, the estimated rotational speed data 47a is subtracted from the indicated angular speed data VB by the subtractor 43, and the output is converted into an analog signal by the D / A converter 44. The converted data is output as motor drive voltage data dv and input to the mirror drive unit 31.

  When the main mirror 5 reaches the mirror position P1 and further rotates, as shown in FIG. 5, it is estimated that the mirror position P2 near the stopper 7 has been reached. , Gradually decrease. The deceleration gradient of the indicated angular velocity data VB is set to be 0 at the mirror rotation position P3 where the main mirror 5 contacts the stopper 7 in FIG.

  Also in the present embodiment, a drive voltage based on the drive voltage signal dv is applied to the mirror drive motor 13a in the mirror rotation position range RB so that the difference between the indicated angular velocity data Vmax and the estimated angular velocity data V0 with respect to VB does not occur as much as possible. The main mirror 5 is rotationally driven. Therefore, according to the mirror driving device of the present embodiment, as in the case of the first embodiment, even when the rotation speed of the main mirror 5 is started at a high speed, the main mirror 5 is in contact with the stopper 7. The bounce is suppressed and the same effect as in the first embodiment is achieved.

  Next, a mirror driving device in the single-lens reflex camera according to the third embodiment of the present invention will be described with reference to FIGS.

  FIG. 6 is a block configuration diagram of an angular velocity instruction unit including a velocity detection unit constituting the mirror driving device of the present embodiment. FIG. 7 is a diagram illustrating changes in the indicated angular velocity and the estimated angular velocity value with respect to the elapsed time in the single-lens reflex camera of the present embodiment.

  The angular velocity instruction unit 12Ca of the mirror driving device of the present embodiment is different from the angular velocity instruction unit 12Aa of the first embodiment in that the main mirror 5 arrives very close to the contact position with the stopper. After it is detected that the angular velocity data has become a very low speed which is a predetermined threshold, the estimated angular velocity data is clipped by 0 only during the time period until the end of the elapsed time range RC where the mirror driving is completely finished. As a result, a small value of the designated angular velocity data VB remains during the time period, and a slight voltage is applied to the mirror drive motor 13a to hold the main mirror 5 in a state where it does not bounce at the stop position. For this purpose, an estimated speed determination unit 71 as a stop control unit and a 0 clip unit 70 are added to the angular velocity instruction unit 12Ca. The other configurations including the mirror drive unit 31 of the angular velocity instruction unit and the single-lens reflex camera are the same as those in the first embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and different parts will be described below.

  In the angular velocity instruction unit 12Ca of the present embodiment, the estimated angular acceleration α0 that is the output of the sense amplifier 37 of the mirror driving unit 31 is accumulated through the A / D converter 29 as in the case of the first embodiment. The estimated angular velocity data is calculated by integration processing. The estimated angular velocity data is input to the selector 46 via the 0 clip unit 70.

  As in the case of the first embodiment, at the elapsed time T31 when the mirror approaches the stopper, the timer 65, which is the control start unit, causes the selector 62 to instruct from the instruction angular velocity A (Vmax) stored in the velocity profile storage unit 12Cb. The output is switched to angular velocity B (VB). The selector 66 switches from the output of the 0 sense output device 28 to the output of the 0 clip 70 to which the estimated angular velocity data of the cumulative calculation unit 67 is input. Therefore, the drive control of the main mirror 5 is performed in the same manner as in the first embodiment until the elapsed time T33 in FIG.

  When the elapsed time T33 is such that the main mirror 5 is substantially in contact with the stopper 7 and the estimated angular velocity data is determined by the estimated velocity determining unit 71 to be an extremely low velocity equal to or less than a predetermined threshold, the output of the 0 clip unit 70 Is switched from the estimated angular velocity data to 0 value data, and the selector 66 outputs 0 value data. Therefore, after the elapsed time T33, the indicated angular velocity data VB output from the selector 62 from the subtractor 63 is continuously input to the D / A converter 64. The indicated angular velocity data VB at this time is an indicated angular velocity that holds an extremely low value, and as the D / A converter 64 drive voltage data dv, the state in which the main mirror 5 is in contact with the stopper 7 is maintained. It is the value of. In other words, the main mirror 5 enters a state in which the bounce is restricted by the torque of the mirror drive motor 13a acting on the stopper 7. This state continues after the elapsed time T33 until the end T34 of the elapsed time range RC.

  According to the mirror driving device of the present embodiment, as in the case of the first embodiment, even when the rotation speed of the main mirror 5 starts at a high speed, the bounce when the main mirror 5 comes into contact with the stopper 7 does not occur. The same effect as in the case of the first embodiment is achieved. In particular, for a predetermined time after the main mirror 5 comes into contact with the stopper, it is pressed against the stopper by the urging force of the mirror drive motor 13a, and the bounce is more effectively regulated.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  The mirror driving device according to the present invention can be used as a mirror driving device that can quickly suppress vibrations that occur during driving of the mirror, can avoid an increase in cost, and can be downsized.

1 is a block configuration diagram illustrating a main configuration of a single-lens reflex camera including a mirror driving device according to a first embodiment of the present invention. It is a block block diagram of the angular velocity instruction | indication part containing the speed detection part of the mirror drive device incorporated in the single-lens reflex camera of FIG. It is a figure which shows the change of the instruction | command angular velocity in the single-lens reflex camera of FIG. It is a block block diagram of the angular velocity instruction | indication part containing the speed detection part of the mirror drive device of 2nd embodiment of this invention. It is a figure which shows the change with respect to the presumed mirror rotation position of the instruction | command angular velocity and angular velocity estimated value in the mirror drive device of FIG. It is a block block diagram of the angular velocity instruction | indication part containing the speed detection part of the mirror drive device of 3rd embodiment of this invention. It is a figure which shows the change with respect to the elapsed time of the instruction | command angular velocity and angular velocity estimated value in the mirror drive device of FIG. It is a system schematic block diagram of what is considered as a conventional single-lens reflex camera system. FIG. 9 is a diagram showing changes in motor instruction voltage and mirror moving speed in the mirror driving state in the single-lens reflex camera of FIG. 8.

Explanation of symbols

2a ... Shooting lens (shooting optical system)
4 ... Mirror unit (mirror part)
5 ... Main mirror (mirror part)
12Aa, 12Ba, 12Ca
... Angular velocity instruction unit (control unit)
12Ab, 12Bb, 12Cb
... Speed profile storage unit (storage unit)
13a ... Mirror drive motor (drive unit)
25, 65 ... Timer (control start unit)
27, 47, 67 ... Cumulative calculation part (speed detection part)
31 ... Mirror drive part (speed detection part)
45 ... Cumulative calculation unit (control start unit)
71 ... Estimated speed determination unit (stop control unit)

Claims (4)

A first position for entering the optical path of the imaging optical system and observing the subject image or at least one of focus adjustment; and a second position for retreating from the optical path of the imaging optical system and performing imaging A mirror that moves between
A drive unit for driving the mirror unit;
A storage unit that stores, as a speed profile, a moving speed at which the mirror unit should transition between the first position and the second position before the mirror unit starts moving and stops.
A speed detection unit that detects a moving speed assumed during driving of the mirror unit;
A control unit that controls the drive unit based on the speed profile and the detected moving speed;
A mirror driving device comprising:   The control unit is configured to start the control after the mirror unit starts moving from the first position or the second position and a predetermined time has elapsed or after the predetermined position has passed. The mirror driving device according to claim 1, further comprising a start unit.   The control unit further includes a stop control unit that performs the control so as to maintain the stop state when the mirror unit stops at the first position or the second position. The mirror driving device according to claim 1.   The mirror driving device according to claim 1, wherein the speed detecting unit further includes a moving speed detection control unit that detects the moving speed based on a driving current during driving of the mirror unit.

Images