JP2013195904A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a release time lag, and increase a consecutive photographing frame speed, without energizing a rear blade holding electromagnet during live view.SOLUTION: An imaging apparatus comprises: a front blade driving member which drives a front blade group; a rear blade driving member which drives a rear blade group; a cam gear which turns the front blade driving member and the rear blade driving member; a motor which drives the cam gear; and a controller which controls the motor. The controller performs control so that a second voltage lower than a first voltage applied when the front blade driving member is released is applied to the motor when the rear blade driving member is released, in normal photographing, and a third voltage lower than the first voltage and higher than the second voltage is applied to the motor when the rear blade driving member is released, in live view photographing.

Description

  The present invention relates to an imaging apparatus such as a digital camera, for example, and relates to an imaging apparatus including a shutter device.

  The shutter device includes a front blade group that travels from a state in which the shutter opening is closed during exposure (hereinafter referred to as a closed state) to a state in which the shutter opens (hereinafter referred to as an open state), and a rear blade group that travels from the open state to the closed state. Have. Each of the front blade group (hereinafter simply referred to as the front blade) and the rear blade group (hereinafter simply referred to as the rear blade) is composed of a plurality of light shielding blades, and the plurality of light shielding blades are connected by an arm so as to form a parallel link. As a result, it moves parallel to the traveling direction.

  An imaging device equipped with a shutter device has a so-called live view display function in which the shutter device is opened before shooting and a moving image generated from the output from the imaging device is displayed on a monitor provided on the back of the camera. There is.

  Patent Document 1 discloses an imaging apparatus that controls a voltage applied to a motor when transitioning from a stop phase of the imaging apparatus to a live view phase in order to reduce the release time lag.

JP 2009-31513 A

  However, Patent Document 1 does not disclose an optimum voltage to be applied to the motor from the live view phase to the imaging phase.

  Therefore, an object of the present invention is to provide an imaging apparatus that does not require energization of the rear blade holding electromagnet during live view, has a short release time lag, and has a fast continuous frame speed.

  An imaging apparatus according to one aspect of the present invention includes a leading blade driving member that drives a leading blade group, a trailing blade driving member that drives a trailing blade group, the leading blade driving member, and the trailing blade driving member. A cam gear that rotates the cam gear, a motor that drives the cam gear, and a control unit that controls the motor, and when the control unit releases the rear blade drive member during normal shooting, A second voltage lower than a first voltage applied when releasing the leading blade driving member is applied to the motor, and when releasing the trailing blade driving member during live view shooting, A third voltage lower than the first voltage and higher than the second voltage is applied to the motor.

  According to the imaging apparatus of the present invention, it is not necessary to energize the rear blade holding electromagnet during live view, the release time lag can be shortened, and the continuous frame speed can be increased.

It is a perspective view when the imaging device which is Example 1 of this invention is seen from diagonally forward. It is a perspective view when the imaging device of Example 1 is seen from diagonally backward. FIG. 2 is a block diagram illustrating a configuration of a control system of the image pickup apparatus of Embodiment 1. FIG. 3 is an exploded perspective view of a shutter device and a quick return mirror mounted on the image pickup apparatus of Embodiment 1. FIG. 6 is a plan view illustrating a charge completion state of a shutter device mounted on the imaging device according to the first embodiment. FIG. 6 is a right side view illustrating a charge completion state of a shutter device mounted on the imaging apparatus of Embodiment 1. FIG. 3 is a plan view illustrating a standby state before travel of a shutter device mounted on the imaging apparatus according to the first embodiment. FIG. 3 is a plan view illustrating a state where a leading blade travel of the shutter device mounted on the imaging device according to the first embodiment is completed. FIG. 6 is a plan view illustrating a state where a rear blade traveling completion of the shutter device mounted on the imaging device according to the first embodiment is completed. 6 is a plan view illustrating a standby state before a live view of a shutter device mounted on the imaging apparatus of Embodiment 1. FIG. FIG. 3 is a plan view illustrating a live view state of a shutter device mounted on the imaging apparatus according to the first embodiment. FIG. 3 is a diagram illustrating a cam diagram and a motor voltage of a shutter device mounted on the imaging apparatus according to the first embodiment. FIG. 9 is a plan view illustrating a charge completion state of a shutter device mounted on an imaging apparatus of Embodiment 2. FIG. 10 is a diagram illustrating a cam diagram and a motor voltage of a shutter device mounted on the imaging apparatus according to the second embodiment.

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

  FIGS. 1 and 2 are perspective views of a single-lens reflex digital camera (imaging device) that is Embodiment 1 of the present invention when viewed obliquely from the front and diagonally rear, respectively.

  The taking lens 2 can be attached to and detached from a single-lens reflex digital camera (hereinafter simply referred to as a camera) 1. The release button 3 is a two-stage switch for instructing the start of photometry and focus detection and instructing photographing. The state where the release button 3 is lightly pushed down to the first level is called “half-press”, and in this state, photometry and focus detection are performed. Pressing from the half-press to the second step is called “full press”, and the shutter device 4 is driven by the full press to perform photographing. The mode dial switch 5 switches various shooting modes of the camera. The image display unit 6 is used for confirmation and selection of a photographed image and selection / setting of a menu function, and the optical viewfinder 7 confirms a subject image.

  FIG. 3 is a block diagram showing the configuration of the control system of the camera 1 and the taking lens 2. The taking lens 2 houses a taking optical system composed of a plurality of optical lenses 8 and an aperture 9. The image sensor 10 is configured by a CCD sensor, a CMOS sensor, or the like that photoelectrically converts a subject image, and the A / D converter 11 converts an analog image signal from the image sensor 10 into digital image data. The timing generation circuit 12 supplies a clock signal and a control signal to the image sensor 10 and the A / D conversion unit 11 and is controlled by the memory control unit 13 and the system control unit 14.

  The memory control unit 13 controls the A / D conversion unit 11, the timing generation circuit 12, the image processing unit 15, the image display memory 16, the display control unit 17, the memory 18, and the compression / decompression unit 19. The data output from the A / D conversion unit 11 is sent to the image display memory 16 via the image processing unit 15 and the memory control unit 13, or directly from the data of the A / D conversion unit 11 via the memory control unit 13. Alternatively, it is written in the memory 18.

  The system control unit 14 is composed of a microcomputer unit including a CPU, and executes a program stored in the memory 27 to control the entire camera.

  The image processing unit 15 performs predetermined image processing such as pixel interpolation processing and color conversion processing on the image data from the A / D conversion unit 11 or the memory control unit 13. The image processing unit 15 performs predetermined calculation processing using the image data output from the A / D conversion unit 11, and based on the obtained calculation result, a TTL (through-the-lens) type AWB (auto white) (Balance) control processing is also performed.

  The memory 18 is a memory for storing captured images, and has a sufficient storage capacity for storing a predetermined number of images. The compression / decompression unit 19 compresses or decompresses the image data read from the memory 18 according to a predetermined image compression method (for example, applied discrete cosine transform), and stores the processed image data in the memory 18. Write. The processed image data is further recorded on the recording medium 20. The recording medium 20 is configured by a nonvolatile memory such as a flash memory, and can be attached to and detached from the camera 1. Further, the image data is read from the recording medium 20 to the memory 18, the image data is written to the image display memory 16 via the image processing unit 15 and the memory control unit 13, and displayed on the image display unit 6 by the display control unit 17. Also used when doing.

  The shutter control unit 21 includes a leading blade electromagnet 39 configured by a leading blade coil and a leading blade yoke that holds the leading blade group of the shutter device 4 in a charged state, a trailing blade coil that holds the trailing blade group in a charged state, and a rear blade coil. The power supply control to the rear blade electromagnet 40 composed of the blade yoke is performed. The motor 41 is driven based on a control signal from the motor control unit 22 and drives the shutter cam gear 36 and the quick return mirror 30 as the first cam gear to a predetermined position in conjunction with the operation of the release button 3.

  The aperture control unit 23 controls the aperture 9, and the focus detection control unit 24 controls focusing of the photographic lens 2. The strobe control unit 26 controls the light emission of the strobe 25.

  The memory 27 stores constants, variables, programs, and the like for operating the system control unit 14.

  The power supply control unit 28 includes a power supply detection circuit, a DC-DC converter, a switch circuit that switches circuit blocks that supply power, and the like. The power supply control unit 28 detects the presence / absence of the power supply unit, the type of power supply, the remaining battery level, etc., and controls the DC-DC converter based on the detection result and the instruction of the system control unit 14 to obtain the necessary voltage For the necessary period, power is supplied to each part including the recording medium.

  FIG. 4 shows an exploded perspective view of the shutter device 4 and the quick return mirror 30.

  The shutter base plate 29 is fixed to a mirror box of a camera body (not shown), and each component constituting a driving mechanism for the leading blade group and the trailing blade group is attached. The quick return mirror 30 swings up and down so as to advance and retreat with respect to the photographing optical path in the mirror box by reciprocatingly rotating about the shaft portion 30a. The mirror drive lever 31 that is a mirror drive member is supported so as to be rotatable about the shaft portion 32 a of the MG main plate 32. A torsion coil spring (not shown) is disposed on the outer periphery of the shaft portion 32a of the MG base plate 32, and this torsion coil spring urges the mirror drive lever 31 in the clockwise direction (the direction in which the quick return mirror 30 is raised). Yes. The shaft portion 31a of the mirror drive lever 31 is in contact with the shaft portion 30b of the quick return mirror 30 which is a driven portion of the quick return mirror 30 disposed below the photographing optical axis. Further, the mirror drive lever 31 abuts on a cam surface 33 a formed on the mirror cam gear 33 as the second cam gear at the shaft portion 31 b of the mirror drive lever 31. The quick return mirror 30 is urged by a spring (not shown) so as to follow the movement of the mirror drive lever 31.

  A leading blade driving lever 34, which is a leading blade driving member, and a trailing blade driving lever 35, which is a trailing blade driving member, are rotatably supported by a leading blade shaft 29a and a trailing blade shaft 29b disposed on the shutter base plate 29, respectively. Has been. The shutter cam gear 36 is centered on a shutter cam gear shaft 29c disposed between the leading blade shaft 29a and the trailing blade shaft 29b on the side opposite to the photographing optical axis from the line connecting the leading blade shaft 29a and the trailing blade shaft 29b. It is rotatably supported. A leading blade charge roller 34 a that is a driven portion provided on the leading blade drive lever 34 and a trailing blade charge roller 35 a that is a driven portion provided on the trailing blade drive lever 35 are formed on the shutter cam gear 36. Touch the cam surface. Further, the leading blade driving lever 34 and the trailing blade driving lever 35 are respectively provided with a leading blade armature 37 and a trailing blade armature 38, and apply a voltage to the leading blade electromagnet 39 and the trailing blade electromagnet 40 disposed on the MG main plate 32. Adsorption occurs when applied. Further, the mirror cam gear 33 is supported so as to be rotatable about a mirror cam gear shaft 29 d disposed in the shutter base plate 29 in the same direction as the photographing optical axis, and is directly connected to the shutter cam gear 36.

  The driving force generated by the motor 41 having an output shaft extending in parallel with the photographing optical axis is driven by the mirror driving lever 31 and the driving force transmitted through the reduction gear train 42 and the mirror cam gear 33 which are transmission members. The shutter cam gear 36 is rotated. Thereby, the reciprocating rotation of the quick return mirror 30 and the charging and releasing of the shutter device 4 can be performed.

  Next, the configuration of the shutter device 4 will be described in detail with reference to FIGS. 5 and 7-9 are plan views showing only the substantially right half of the shutter device 4 incorporated in the camera 1 as viewed from the subject side. In these drawings, the MG ground plane 32 is omitted for easy viewing of the drawings. 6 is a right side view of the shutter device 4 shown in FIG. 5, and illustration of some components is omitted.

  FIG. 5 shows an overcharge state, that is, a state where the camera is stopped. 7 shows a standby state before traveling, FIG. 8 shows a leading blade traveling completion state, and FIG. 9 shows a trailing blade traveling completed state.

  A torsion coil spring (not shown) is disposed on the outer periphery of the leading blade shaft 29a, and this torsion coil spring urges the leading blade drive lever 34 in the counterclockwise direction (direction in which the leading blade group travels) in FIG. ing. Reference numeral 29e denotes an aperture through which the subject luminous flux passes, and is formed on the shutter base plate 29.

  A leading blade driving pin 34 b formed at the tip of the leading blade driving lever 34 penetrates a leading blade groove 29 f formed in the shutter base plate 29 and engages with a leading blade driving arm (not shown). The leading blade drive arm is connected to the leading blade group 34c via a link mechanism. The leading blade group 34b is composed of a plurality of shutter blades.

  When the leading blade driving pin 34b is moved along the leading blade groove 29f by the rotation of the leading blade driving lever 34, the leading blade driving arm is rotated to expand or superimpose the leading blade group 34c. By the operation of the front blade group 34c, the aperture 29e can be opened (a state in which the subject light beam is allowed to pass) or can be closed (a state in which the subject light beam is substantially blocked). Here, the rotation range of the leading blade drive lever 34 is limited by the leading blade groove 29f.

  The leading blade drive lever 34 is provided with a leading blade armature support portion 34d. A through blade portion (not shown) formed in the front blade armature support portion 34d has a flange portion larger than the inner diameter of the through hole portion, and is attached to the front blade armature 37 integrally with the front blade armature shaft. 37a is engaged. The leading blade armature shaft 37 a extends in a direction substantially orthogonal to the suction surface of the leading blade armature 37.

  A compression spring (not shown) is disposed between the leading blade armature 37 and the leading blade armature support portion 34d and on the outer periphery of the leading blade armature shaft 37a, and the leading blade armature 37 and the leading blade armature support portion 34d are connected to each other. It is energized in a direction away from each other (vertical direction in FIG. 5).

  The leading blade electromagnet 39 includes a leading blade yoke 39a and a leading blade coil 39b provided on the outer periphery of the leading blade yoke 39a. When a voltage is applied to the leading blade coil 39b, a magnetic force can be generated in the leading blade yoke 39a, and the leading blade armature 37 can be attracted by this magnetic force.

  A torsion coil spring (not shown) is arranged on the outer periphery of the rear blade shaft 29b, and this torsion coil spring urges the rear blade drive lever 35 in the counterclockwise direction (the direction in which the rear blade group travels) in FIG. ing.

  A rear blade drive pin 35b formed at the tip of the rear blade drive lever 35 passes through a rear blade groove 29g formed in the shutter base plate 29 and engages with a rear blade drive arm (not shown). The rear blade drive arm is connected to the rear blade group 35c (in a superimposed state in FIGS. 5, 7, and 8) via a link mechanism. The rear blade group 35c is composed of a plurality of shutter blades.

  When the trailing blade driving pin 35b is moved along the trailing blade groove 29g by the rotation of the trailing blade driving lever 35, the trailing blade driving arm is rotated to expand or superimpose the trailing blade group 35c. By the operation of the rear blade group 35c, the aperture 29e can be opened (a state in which the subject light beam is allowed to pass) or can be closed (a state in which the subject light beam is substantially blocked). Here, the rotation range of the trailing blade driving lever 35 is limited by the trailing blade groove 29g.

  The rear blade drive lever 35 is provided with a rear blade armature support portion 35d. A through-hole portion (not shown) formed in the rear-blade armature support portion 35d has a flange portion larger than the inner diameter of the through-hole portion, and is attached to the rear-blade armature 38 integrally. 38a is engaged. The rear blade armature shaft 38 a extends in a direction substantially orthogonal to the suction surface of the rear blade armature 38.

  A compression spring (not shown) is disposed between the rear blade armature 38 and the rear blade armature support portion 35d and on the outer periphery of the rear blade armature shaft 38a, and the rear blade armature 38 and the rear blade armature support portion 35d are connected to each other. It is energized in a direction away from each other (vertical direction in FIG. 5).

  The rear blade electromagnet 40 includes a rear blade yoke 40a and a rear blade coil 40b provided on the outer periphery of the rear blade yoke 40a. When a voltage is applied to the rear blade coil 40b, a magnetic force can be generated in the rear blade yoke 40a, and the rear blade armature 38 can be attracted by this magnetic force.

  A leading blade first cam surface 36 a 1 and a leading blade second cam surface 36 a 2 are formed on the leading blade cam portion 36 a formed on the shutter cam gear 36. The leading blade second cam surface 36a2 is a tapered surface that connects the leading blade first cam surface 36a1 and the cam top. The cam lift of the leading blade second cam surface 36a2 is set to be smaller than the cam lift of the leading blade first cam surface 36a1. When the shutter cam gear 36 rotates, the leading blade first cam surface 36a1 comes into contact with and traces the leading blade charge roller 34a, so that the leading blade driving lever 34 is rapidly charged to more than half the operating angle. Next, the leading blade second cam surface 36a2 comes into contact and traces, thereby slowly charging. In FIG. 5, the leading blade cam portion 36a rotates the leading blade drive lever 34 in the clockwise direction (when the leading blade group 34c is superposed) in a state where the traveling of the leading blade group 34c is completed. By doing so, a charge operation is performed.

  A rear blade first cam surface 36b1 and a rear blade second cam surface 36b2 are formed in the rear blade cam portion 36b formed in the shutter cam gear 36. The rear blade second cam surface 36b2 is a tapered surface that connects the rear blade first cam surface 36b1 and the cam top. Further, the cam lift of the rear blade second cam surface 36b2 is set smaller than the cam lift of the rear blade first cam surface 36b1. When the shutter cam gear 36 rotates, the trailing blade first cam surface 36b1 comes into contact with and traces the trailing blade charge roller 35a, so that the trailing blade driving lever 35 is rapidly charged to more than half the operating angle. Next, the trailing blade second cam surface 36b2 comes into contact and traces, thereby slowly charging. In FIG. 5, the trailing blade cam portion 36b rotates the trailing blade drive lever 35 in the clockwise direction (when the trailing blade group 35c is in the unfolded state) in a state where the traveling of the trailing blade group 35c is completed. By doing so, a charge operation is performed.

  The cam surface 33 a formed on the mirror cam gear 33 abuts on the shaft portion 31 b of the mirror drive lever 31 and rotates the mirror drive lever 31 according to the rotation of the mirror cam gear 33. In FIG. 5, the cam surface 33a formed on the mirror cam gear 33 performs a charging operation by rotating the mirror drive lever 31 in which the quick return mirror 30 is in the up state in the counterclockwise direction.

  Next, the operation of the shutter device 4 when actually shooting is described.

  First, the operation of the shutter device 4 in a mode for photographing while observing a subject with the optical viewfinder 7 (normal photographing mode) will be described with reference to FIGS. 5 and 7 to 9.

  When the release button 3 is fully pressed in the state of FIG. 5, the energization of the leading blade coil 39b and the trailing blade coil 40b is started, and the rotation of the motor 41 causes the mirror cam gear 33 to rotate clockwise and the shutter cam gear 36 to Rotates counterclockwise. Then, the shaft portion 31b of the mirror drive lever 31 falls to the cam bottom of the cam surface 33a, so that the mirror drive lever 31 jumps up the quick return mirror 30. Further, the leading blade charge roller 34a and the trailing blade charge roller 35a are separated from the leading blade cam portion 36a and the trailing blade cam portion 36b of the shutter cam gear 36, respectively, and shift to the standby state before traveling shown in FIG. In FIG. 7, since the leading blade armature 37 and the trailing blade armature 38 are electromagnetically attracted and held, the leading blade drive lever 34 and the trailing blade drive lever 35 do not rotate. After that, a time interval corresponding to the shutter time set by the system control unit 14 is provided, and energization of the leading blade coil 39b and the trailing blade coil 40b is turned off. When the leading blade coil 39b is de-energized, the leading blade drive lever 34 rotates counterclockwise, and the leading blade travel completion state of FIG. 8 is achieved. When the energization of the trailing blade coil 40b is turned off, the trailing blade driving lever 35 rotates counterclockwise, and the trailing blade traveling completion state of FIG. 9 is obtained.

  After the exposure to the image sensor 10, the mirror cam gear 33 rotates clockwise and the shutter cam gear 36 rotates counterclockwise by the rotation of the motor 41. Then, the cam surface 33a pushes the shaft portion 31b of the mirror drive lever 31, and the leading blade cam portion 36a and the trailing blade cam portion 36b push the leading blade charge roller 34a and the trailing blade charge roller 35a, respectively. Return to the state of 5.

  Next, the operation of the shutter device 4 when performing hybrid shutter shooting in the live view mode will be described with reference to FIGS. 5 and 8 to 11. 10 shows a standby state before live view, and FIG. 11 shows a live view state. In the live view state, the subject image incident on the image sensor 10 is displayed on the image display unit 6.

  When the live view mode is selected by the mode dial switch 5 in the state of FIG. 5, the energization of the leading blade coil 39b is started and the mirror cam gear 33 is rotated clockwise and the shutter cam gear 36 is rotated counterclockwise by the rotation of the motor 41. Rotate clockwise. Then, as shown in FIG. 10, the mirror drive lever 31 springs up the quick return mirror 30 by the shaft portion 31b of the mirror drive lever 31 falling to the cam bottom of the cam surface 33a. Further, although the leading blade charge roller 34a is separated from the leading blade cam portion 36a of the shutter cam gear 36, the trailing blade charge roller 35a transitions to a state of riding on the trailing blade cam portion 36b. The front blade drive lever 34 travels by cutting off the energization of the front blade coil 39b in the state of FIG. 10, and the live view state of FIG. 11 is entered. In this live view state, the trailing blade charge roller 35a is on the trailing blade cam portion 36b, and thus it is not necessary to energize the trailing blade coil 40b.

  When the release button 3 is fully pressed in the live view state, energization to the rear blade coil 40b is started, and the rotation of the motor 41 causes the mirror cam gear 33 to rotate clockwise and the shutter cam gear 36 to rotate counterclockwise. , Transition to the state of FIG. Thereafter, a time interval corresponding to the shutter time set by the system control unit 14 is provided, and reset scanning of the pixels of the image sensor 10 (hereinafter referred to as an electronic leading blade) and energization off of the trailing blade coil 40b are executed. As a result, the state shown in FIG. 9 is entered.

  After the exposure to the image sensor 10, the charging operation is performed by the rotation of the motor 41, and the state returns to the live view state of FIG. 11 through the states of FIGS.

  FIG. 12 is a diagram showing cam diagrams of the mirror cam gear 33 and the shutter cam gear 36 and voltages applied to the motor 41 in each section. This is obtained by detecting the phase of a phase contact piece (not shown) provided on the back surface of the mirror cam gear 33 or the shutter cam gear 36. Here, the movement of the shutter device 4 will be described from the viewpoint of the cam diagram with reference to FIG.

  The camera stop phase (first phase) shown in FIG. 5 is a cam diagram in which the rotation angle of each cam is between 0 ° and 55 °, and the cam surface 33a of the mirror cam gear 33 and the tip of the shutter cam gear 36. The blade cam portion 36a and the trailing blade cam portion 36b are all in a cam top state.

  As each cam gear rotates from 55 ° to 85 °, the cam surface 33a of the mirror cam gear 33 retreats from the rotation locus of the shaft portion 31b of the mirror drive lever 31, and the quick return mirror 30 is moved up. Further, the leading blade cam portion 36a of the shutter cam gear 36 is retracted from the rotation locus of the leading blade charge roller 34a, so that the leading blade driving lever 34 is released. As described above, a transition is made from the camera stop phase to the live view phase (second phase) indicated between 85 ° and 105 °.

  As the shutter cam gear 36 rotates from 105 ° to 135 °, the rear blade cam portion 36b of the shutter cam gear 36 retreats from the rotation locus of the rear blade charge roller 35a, thereby releasing the rear blade drive lever 35. . In this way, a transition is made from the live view phase to the imaging phase (third phase) indicated between 135 ° and 185 °.

  Between 185 ° and 360 °, each cam sequentially changes from bottom to top and performs a charging operation. The cam surface 33a of the mirror cam gear 33 performs the charging operation of the mirror drive lever 31 in the section from 185 ° to 240 °. Further, the first blade first cam surface 36 a 1 performs a charging operation from 240 ° to 296 °, and performs a charging operation that is more than half the operating angle of the leading blade drive lever 34. The leading blade second cam surface 36a2 performs a charging operation from 296 ° to 360 °, and the leading blade driving lever 34 is completely charged. The trailing blade first cam surface 36b1 performs a charging operation from 281 ° to 341 °, and performs a charging operation that is more than half the operating angle of the trailing blade drive lever 35. The rear blade second cam surface 36b2 performs the charging operation from 341 ° to 360 °, and the charging operation of the rear blade driving lever 35 is completed. That is, at 360 °, charging of the leading blade driving lever 34 and the trailing blade driving lever 35 is completed.

  The leading blade first cam surface 36a1 and the trailing blade first cam surface 36b1 perform a charging operation of more than half the operating angle of the leading blade driving lever 34 and the trailing blade driving lever 35, respectively, thereby leading to the leading blade second cam surface 36a2. And the rear blade second cam surface 36b2 can be set more gently. Therefore, the angular velocity when the leading blade armature 37 is in contact with the leading blade electromagnet 39 and the angular velocity when the trailing blade armature 38 is in contact with the trailing blade electromagnet 40 can be further suppressed, and the durability of the shutter device is further improved. Can be made.

  Here, in order to prevent exposure during charging, it is necessary to charge the leading blade drive lever 34 before the trailing blade drive lever 35. In order to gently charge the leading blade drive lever 34 and improve the durability of the shutter device 4, the charging angle (64 °) of the leading blade second cam surface 36a2 is set to the charging angle (19 ° of the trailing blade second cam surface 36b2). The charging operation is completed simultaneously.

  In this embodiment, the leading blade driving lever 34 and the trailing blade driving lever 35 are configured such that the leading blade armature 37 and the trailing blade armature 38 are in contact with the leading blade electromagnet 39 and the trailing blade electromagnet 40, respectively, at a charge angle of 60 °. . Since the charge angle of the drive lever by the first blade first cam surface 36a1 and the rear blade first cam surface 36b1 is preferably 50 ° or more, the front blade drive lever 34 has a charge angle of 57 ° and the rear blade drive lever 35 has a charge. The cam surface is switched at an angle of 57.5 °.

  In the above configuration, in order to increase the continuous frame speed, it is necessary to increase the rotation speed of the cam by increasing the torque of the motor 41 and increasing the gear ratio of the reduction gear train 42. It is also important to minimize the cam idle time by minimizing the camera stop phase and the imaging phase.

  Next, the voltage applied to the motor 41 will be described with reference to FIG. In FIG. 12, a section where no voltage is shown is a short brake state in which the terminals of the motor 41 are short-circuited, and a brake that impedes the rotation of the motor 41 is applied.

  First, consider the interval from the camera stop phase to the imaging phase. Applied to the motor 41 in the case of a direct transition from the camera stop phase to the shooting phase (normal shooting) and in the case of the transition from the camera stop phase to the live view phase and then the live view phase to the shooting phase (live view shooting). The voltage will be described.

  In the case of normal shooting, the voltage (first voltage) V1 applied to the motor 41 from the shooting phase to the rear blade release start (55 ° to 105 °) from the rear blade release start to the shooting phase (105 ° to 135 °). ) (The second voltage) V2 applied to the motor 41 is set low. By doing in this way, there are the following two effects.

  The first effect is to prevent the adsorption failure of the trailing blade electromagnet 40. As described above, if the torque of the motor 41 is simply increased in order to increase the release time lag or the continuous shooting frame speed, the speed when the shutter cam gear 36 performs the rear blade releasing operation is increased. That is, the speed at the time of collision between the rear blade drive lever 35 and the rear blade armature shaft 38a is increased. For this reason, there is a risk that the rear blade drive lever 35 travels without being attracted by the rear blade electromagnet 40. On the other hand, the leading blade side is released as soon as the shutter cam gear 36 starts to move from the stopped state. Therefore, since the motor 41 is released in a state where the rotational speed is not so high, the above problem is not as remarkable as the rear blade side. In this embodiment, by reducing the voltage applied to the motor 41 when the rear blade is released, the speed at which the rear blade drive lever 35 collides with the rear blade armature shaft 38a when the rear blade is released can be reduced. By doing in this way, since the speed at the time of the collision of the rear blade drive lever 35 and the rear blade armature shaft 38a is high, the rear blade electromagnet 40 cannot be attracted and the rear blade drive lever 35 travels. Can be suppressed.

  The second effect is that the photographing phase range can be set small and the frame speed can be increased. By controlling the voltage applied to the motor 41 as described above, the overrun of each cam gear when the motor is stopped is smaller than when a single voltage is applied to the motor 41. That is, the photographing phase range can be set small, and the idling time during charging is shortened, leading to an increase in frame speed.

  In the case of live view shooting, the voltage (third voltage) V3 applied to the motor 41 at the time of transition from the live view phase to the shooting phase is lower than the voltage V1 and higher than the voltage V2. Since driving with the voltage V2 is after driving with the voltage V1, the motor 41 and each cam gear are in a rotating state. On the other hand, when driving with the voltage V3, the motor 41 and each cam gear are stopped.

  Consider a case where the voltage V3 is equal to or lower than the voltage V2. At this time, the overrun (driving with the voltage V3) in the case of transition from the live view phase to the photographing phase is smaller than the overrun (driving with the voltages V1 and V2) in the case of direct transition from the camera stop phase to the photographing phase. Become. Therefore, it is necessary to set the width of the imaging phase with reference to an overrun in the case of a direct transition from the camera stop phase to the imaging phase. However, since the overrun during transition from the live view phase to the shooting phase is small, the idling time at the start of charging in live view shooting becomes longer, and the continuous frame speed in live view shooting becomes slower. End up.

  Therefore, as described above, by controlling the voltage V3 to be higher than the voltage V2, it is possible to reduce as much as possible the overrun in the case of a direct transition from the camera stop phase to the imaging phase. Then, the overrun in the case of transition from the live view phase to the imaging phase can be made equal to the overrun in the case of direct transition from the camera stop phase to the imaging phase. That is, the shooting phase range can be set small, and the idle running time during charging is shortened during both normal shooting and live view shooting, leading to an increase in frame speed.

  The voltage (fourth voltage) V4 applied to the motor 41 when the camera stop phase is shifted to the live view phase is set lower than the voltage V1. Therefore, since the overrun when each cam gear stops at the live view phase can be further reduced, the width of the live view phase can be reduced. Therefore, since the interval (55 ° to 135 °) from the camera stop phase to the imaging phase is set smaller than when the voltage applied to the motor 41 is not switched, the release time lag during normal imaging is increased. It can be suppressed and the frame speed can be increased.

  Here, the voltage V3 and the voltage V4 may be equal. By doing so, the type of voltage applied to the motor 41 can be reduced, so that there is an advantage that the control is simplified.

  Next, consider a section in which a charging operation is performed from the imaging phase to the camera stop phase. Regarding the charging operation, normal shooting and live view shooting perform the same operation.

  When the torque of the motor 41 increases, the acceleration of the motor 41 increases, so that the angular velocity when the leading blade armature 37 contacts the leading blade electromagnet 39 and the angular velocity when the trailing blade armature 38 contacts the trailing blade electromagnet 40 are large. Become. However, as described above, the charge angle (64 °) of the leading blade second cam surface 36a2 is larger than the charge angle (19 °) of the trailing blade second cam surface 36b2, so The effect is small, and the effect on the rear blade side becomes significant. In order to solve this problem, the charge angle of the rear blade second cam surface 36b2 may be further increased. However, since the cam is limited to 360 ° as a whole, the setting is limited.

  Therefore, in this embodiment, from the voltage V5 applied to the motor 41 when charging from the imaging phase to the rear blade second cam surface 36b2 (185 ° to 341 °), from the rear blade second cam surface to the camera stop phase. (341 ° to 360 °) The voltage V6 at the time of charging is lowered. By doing so, the angular velocity when the trailing blade armature 38 contacts the trailing blade electromagnet 40 can be further reduced. That is, the angular velocity when the leading blade armature 37 is in contact with the leading blade electromagnet 39 and the angular velocity when the trailing blade armature 38 is in contact with the trailing blade electromagnet 40 can be made even though the frame speed is increased. It can be as small as possible. By doing this, the difference in the degree of damage between the front blade and rear blade armature and the electromagnet in durability is reduced, and the separation time of the holding electromagnets of the front blade and rear blade changes almost together. Can be small. Further, since the overrun at the completion of charging is reduced, the width of the camera stop phase can be set small. If the width of the camera stop phase is reduced, the idle running time of the motor 41 when driving from the camera stop phase to the imaging phase is shortened, leading to a reduction in the release time lag and an increase in the continuous shooting frame speed.

  Further, the driving at the voltage V6 is a section in which the charge load is lightened because it is a section charged by the first blade second cam surface 36a2 and the rear blade second cam surface 36b2 that are slowly charged. Therefore, the voltage V6 can be set to a low voltage as long as the motor 41 cannot withstand the charge load and does not stop. In other words, since the charging load is lighter, the voltage V6 can be set to a lower voltage, and the overrun when charging is completed can be reduced.

  In addition, about the switching of the voltage applied to the motor 41 demonstrated so far, you may make an effective voltage low using well-known PWM control.

  Hereinafter, an image pickup apparatus according to the second embodiment of the present invention will be described with reference to FIGS.

  FIG. 13 is a plan view showing a charging operation completion state of the shutter device mounted on the imaging apparatus of the second embodiment, and FIG. 14 is a cam diagram of the shutter apparatus mounted on the imaging apparatus of the second embodiment and each It is a figure which shows the voltage applied to the motor 41 in the area.

  The difference from the first embodiment is the shape of the leading blade second cam surface 36a2. In the first embodiment, the leading blade second cam surface 36a2 is from 296 ° to 360 °, whereas in the second embodiment, it is shortened from 296 ° to 311 °. Further, as shown in FIG. 14, the charging operation on the leading blade second cam surface 36a2 ends before the charging operation starts on the trailing blade second cam surface 36b2. That is, the charging operation of the leading blade drive lever 34 is completed before driving at the voltage 6. Therefore, since the load during the charging operation can be reduced, the voltage V6 can be set lower. By suppressing the voltage V6 lower, the overrun of the shutter cam gear 36 when the charging operation is completed can be reduced, and the width of the camera stop phase can be set smaller. Therefore, since the idle running time of the shutter cam gear 36 is reduced, the continuous shooting frame speed can be further increased.

  On the other hand, since the charge operation area of the leading blade second cam surface 36a2 is smaller than that of the first embodiment, the first embodiment is more advantageous with respect to the durability of the shutter.

  Since other parts are the same as those in the first embodiment, detailed description thereof is omitted.

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

DESCRIPTION OF SYMBOLS 1 Camera 22 Motor control part 34 Leading blade drive lever 35 Rear blade driving lever 36 Shutter cam gear 41 Motor

Claims (3)

A leading blade driving member for driving the leading blade group;
A rear blade drive member for driving the rear blade group;
A cam gear for rotating the leading blade driving member and the trailing blade driving member;
A motor for driving the cam gear;
A control unit for controlling the motor,
The controller is
During normal shooting,
When releasing the trailing blade driving member, a second voltage smaller than the first voltage applied when releasing the leading blade driving member is applied to the motor;
During Live View shooting,
An image pickup apparatus that applies a third voltage, which is lower than the first voltage and higher than the second voltage, to the motor when releasing the rear blade driving member.   The said control part applies the 4th voltage lower than the said 1 voltage to the said motor, when releasing the said front-wing drive member at the time of live view imaging | photography. Imaging device. The imaging apparatus according to claim 2, wherein the third voltage is equal to the fourth voltage.