JP2018112734A - Shutter device and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shutter device that can shorten a release time lag while reducing power consumption.SOLUTION: A shutter device (113) comprises: a shutter bottom board (1) in which an opening (1a) is formed; light shielding members (2, 3) that can be moved between a closed state for closing the opening and an opening state for opening the opening; cam members (15, 16) that can be rotated within a first angular range (15d, 16d), a second angular range (15f, 16f), and a third angular range (15e, 16e) between the first angular range and second angular range, and moves the light shielding members through rotation within the third angular range; motors (19, 20) that drive to rotate the cam members; urging members (9, 10) that urge the cam members to rotate from the first angular range toward the third angular range; and regulation members (22, 23) that regulate the urge against the cam members performed by the urging members in at least a part of the first angular range.SELECTED DRAWING: Figure 5(a)

Description

  The present invention relates to a shutter device that can operate based on a driving force of a motor.

  Patent Document 1 discloses a shutter device in which a shutter blade opens and closes an opening by rotating a drive ring using a stepping motor. This drive ring has an acceleration region where the shutter blade does not open and close even when rotated, and an exposure region where the shutter blade opens and closes the opening due to rotation.

JP-A-7-56211

  However, the shutter device of Patent Document 1 may not be able to sufficiently accelerate the drive ring in the acceleration region depending on the output of the motor to be used, and may not be able to obtain the required curtain speed during the high shutter speed. Such a shutter device can increase the curtain speed by configuring the drive ring to be assisted by a spring in a part of the acceleration region, but it is necessary to charge the spring for each release. The release time lag will be longer. At this time, in order to shorten the release time lag, it is necessary to stand by with the spring charged. However, in order to stand by (stop) with the spring charged, it is necessary to energize the motor, which increases power consumption.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a shutter device and an imaging device capable of reducing the release time lag while suppressing power consumption.

  A shutter device according to one aspect of the present invention includes a shutter base plate in which an opening is formed, a closed state in which the opening is closed, a light shielding member that is movable in an open state in which the opening is opened, a first angle range, 2 and a third angle range between the first angle range and the second angle range, and the light shielding member is moved by the rotation in the third angle range. A cam member; a motor that rotationally drives the cam member; an urging member that urges the cam member to rotate from the first angle range toward the third angle range; And a regulating member that regulates the urging of the urging member to the cam member in at least a part of the angle range.

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

  According to the present invention, the release time lag can be shortened while suppressing power consumption.

It is the disassembled perspective view which looked at the shutter apparatus in 1st Embodiment from the to-be-photographed object side. It is the disassembled perspective view which looked at the shutter apparatus in 1st Embodiment from the image pick-up element side. It is the front view which looked at the cam gear of the shutter device in a 1st embodiment from the image sensor side. It is a figure which shows the relationship between the rotation angle of the cam gear of the shutter apparatus in 1st Embodiment, and the movement position of a shutter blade | wing. It is the schematic at the time of seeing the relationship between the cam gear of the shutter apparatus in 1st Embodiment, an assist spring, and a spring control member as a plane from the radial direction of a cam gear. It is the schematic at the time of seeing the relationship between the cam gear of the shutter apparatus in 1st Embodiment, an assist spring, and a spring control member as a plane from the radial direction of a cam gear. It is the schematic at the time of seeing the relationship between the cam gear of the shutter apparatus in 1st Embodiment, an assist spring, and a spring control member as a plane from the radial direction of a cam gear. It is the schematic at the time of seeing the relationship between the cam gear of the shutter apparatus in 1st Embodiment, an assist spring, and a spring control member as a plane from the radial direction of a cam gear. It is the schematic at the time of seeing the relationship between the cam gear of the shutter apparatus in 1st Embodiment, an assist spring, and a spring control member as a plane from the radial direction of a cam gear. It is the schematic at the time of seeing the relationship between the cam gear of the shutter apparatus in 1st Embodiment, an assist spring, and a spring control member as a plane from the radial direction of a cam gear. It is the schematic at the time of seeing the relationship between the cam gear of the shutter apparatus in 1st Embodiment, an assist spring, and a spring control member as a plane from the radial direction of a cam gear. It is a figure which shows the standby state before imaging | photography of the shutter apparatus in 1st Embodiment. It is a figure which shows the state of the blade travel completion of the shutter apparatus in 1st Embodiment. It is a block diagram of the imaging device in a 1st embodiment. It is the disassembled perspective view which looked at the shutter apparatus in 2nd Embodiment from the to-be-photographed object side. It is the disassembled perspective view which looked at the shutter apparatus in 2nd Embodiment from the image pick-up element side. It is the front view which looked at the cam gear of the shutter apparatus in 2nd Embodiment from the to-be-photographed object side. It is a perspective view which shows the drive member of the shutter apparatus in 2nd Embodiment. It is the front view which looked at the assist gear of the shutter apparatus in 2nd Embodiment from the to-be-photographed object side. It is a figure which shows the standby state before imaging | photography of the shutter apparatus in 2nd Embodiment. It is a figure which shows the state in the middle of the transition of the cam gear of the shutter apparatus in 2nd Embodiment. It is a figure which shows the state which the cam gear of the shutter apparatus in 2nd Embodiment is connected with the assist gear, and is receiving urging | biasing force. It is a figure which shows the state by which the connection of the cam gear and assist gear of the shutter apparatus in 2nd Embodiment is cancelled | released. It is a figure which shows the state of the blade travel completion of the shutter apparatus in 2nd Embodiment.

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

(First embodiment)
First, the imaging device according to the first embodiment of the present invention will be described with reference to FIG. FIG. 8 is a block diagram of the imaging apparatus 400. In FIG. 8, 401 is an imaging lens (imaging optical system), 113 is a focal plane shutter (shutter device), 403 is an image sensor, 481 is a mirror member, and 482 is a viewfinder device. When the imaging apparatus 400 is in the finder observation state as shown in FIG. 8, a part of the subject light beam that has passed through the imaging lens 401 is reflected by the mirror member 481 located in the imaging optical path, and the finder apparatus. 482. As a result, the photographer can observe the subject image via the finder device 482. When the viewfinder observation state is shifted to the photographing state or the live view state, the mirror member 481 is retracted from the photographing optical path by a mirror member driving device (not shown). Thereby, the subject light from the imaging lens 401 is directed to the imaging element 403.

  A focal plane shutter 113 is disposed on the object side of the image sensor 403. Reference numeral 411 denotes a shutter drive circuit that drives the focal plane shutter 113. The focal plane shutter 113 has a plurality of blade units (first blade unit 2 and second blade unit 3 (see FIG. 1)), and is drive-controlled by a CPU 409 (control unit) via a shutter drive circuit 411. The The focal plane shutter 113 includes motors 19 and 20 (see FIG. 1). The motors 19 and 20 rotate and drive the first cam gear 15 and the second cam gear 16, and are controlled by a control circuit 312 and a drive circuit 313 included in the shutter drive circuit 411.

  Reference numeral 498 denotes a switch (SW1) for starting preparation for photographing, and reference numeral 499 denotes a switch (SW2) for starting photographing. The switch (SW1) 498 and the switch (SW2) 499 are configured as a two-stage switch. The switch (SW1) 498 is turned on in the first stroke, and the switch (SW2) 499 is turned on in the second stroke.

  The imaging element 403 includes a CMOS image sensor and the like, photoelectrically converts a subject image (optical image) formed via the imaging lens 401 (imaging optical system), and outputs image data (analog image signal). An AFE (Analog Front End) 404 converts an analog image signal output from the image sensor 403 into a digital image signal. A DSP (Digital Signal Processor) 405 performs various image processing, compression / decompression processing, and the like on the digital image signal output from the AFE 404, and outputs the processed image data.

  A recording medium 406 records image data processed by the DSP 405. The display unit 407 includes a liquid crystal display (LCD) and the like, and displays captured images and various menu screens. A TG 408 is a timing generator and drives and controls the image sensor 403. The RAM 410 is connected to the DSP 405 and temporarily stores image data and the like.

  The lens control unit 491 outputs lens information such as the focal length, the aperture diameter, the exit pupil diameter, and the distance between the exit pupil and the image sensor 403 of the imaging lens 401 to the CPU 409. The lens control unit 491 drives a diaphragm, a lens, and the like included in the imaging lens 401 according to control by the CPU 409 (control unit). The detection results of the detection means included in the lens control means 491 are input to the CPU 409. The CPU 409 controls the AFE 404, DSP 405, TG 408, shutter drive circuit 411, and lens control means 491.

  Next, the configuration of the focal plane shutter 113 (shutter device) will be described with reference to FIGS. 1 and 2. FIG. 1 is an exploded perspective view of the focal plane shutter 113 as viewed from the subject side. FIG. 2 is an exploded perspective view of the focal plane shutter 113 as viewed from the image sensor 403 side (image plane side).

  A cover plate 8 is attached to the shutter base plate 1 on the image sensor 403 side (image plane side). Between the shutter base plate 1 and the cover plate 8, a first blade unit 2 including blades 2a, 2b, 2c and blade arms 2d, 2e, and blades 3a, 3b, 3c and blade arms 3d, 3e The 2nd blade | wing unit 3 containing is provided. Apertures 1a and 8a (openings) are formed in the shutter base plate 1 and the cover plate 8, respectively. Each of the first blade unit 2 and the second blade unit 3 is a light shielding member that is movable between a closed state in which the aperture 1a is closed and an open state in which the aperture 1a is opened. The shutter base plate 1 has shafts 1b and 1c erected on the subject side. A first drive member 11 is rotatably attached to the shaft 1b and a second drive member 12 is rotatably attached to the shaft 1c. Yes.

  The shutter base plate 1 is provided with bearings 1d, 1e, 1f, and 1g. A shaft 15a of the first cam gear 15 is fitted to the bearings 1d and 1f, and a shaft 16a of the second cam gear 16 is fitted to the bearings 1e and 1g, respectively. The shafts are rotatably supported. The shutter base plate 1 is provided with shafts 1h, 1i, 1j, and 1k on the image sensor 403 side. The first blade unit 2 is disposed on the shafts 1h and 1i, and the shafts 1j and 1k are coupled with the first blade unit 2. Two blade units 3 are rotatably mounted.

  The shaft 1b of the shutter base plate 1 is fitted into the hole 11a of the first drive member 11, and the first drive member 11 is configured to be rotatable. The cam engaging pin 11 b of the first drive member 11 is slidably fitted (engaged) with the cam groove 15 c of the first cam gear 15, and the cam engagement pin 11 b follows the rotation of the first cam gear 15. The combination pin 11b is configured to drive the first drive member 11 along the cam groove 15c. The shaft 1c of the shutter base plate 1 is fitted into the hole 12a of the second drive member 12, and the second drive member 12 is configured to be rotatable. The cam engaging pin 12 b of the second drive member 12 is slidably fitted (engaged) with the cam groove 16 c of the second cam gear 16, and the cam engagement pin 12 b is rotated according to the rotation of the second cam gear 16. The combination pin 12b is configured to drive the second drive member 12 along the cam groove 16c.

  The first blade unit 2 includes two blade arms 2d and 2e and three blades 2a, 2b and 2c. The holes 2f and 2g of the two blade arms 2d and 2e are pivotally attached to the shafts 1h and 1i, respectively, on the image pickup element 403 side of the shutter base plate 1. The three blades 2a, 2b, and 2c are sequentially pivoted through the connecting shaft 7 toward the other ends of the blade arms 2d and 2e. A hole 2h is formed in the blade arm 2, and the drive pin 11c of the first drive member 11 is engaged with the hole 2h. The first blade unit 2 can shift between a closed state where the blades 2a, 2b and 2c cover the aperture 1a of the shutter base plate 1 and an open state where the blade 1a is retracted from the aperture 1a as the first driving member 11 rotates. It is configured as follows.

  The second blade unit 3 includes two blade arms 3d and 3e and three blades 3a, 3b, and 3c. The holes 3f and 3g of the two blade arms 3d and 3e are pivotally attached to the shafts 1j and 1k, respectively, on the image pickup device 403 side of the shutter base plate 1. The three blades 3a, 3b, and 3c are sequentially pivoted through the connecting shaft 7 toward the other ends of the blade arms 3d and 3e. A hole 3h is formed in the blade arm 3, and the drive pin 12c of the second drive member 12 is engaged with the hole 3h. According to the rotation of the second driving member 12, the second blade unit 3 can shift between a closed state where the blades 3a, 3b, 3c cover the aperture 1a of the shutter base plate 1 and an open state where the blade 1a is retracted from the aperture 1a. It is configured as follows.

  The inner diameter portion of the first assist spring 9 (biasing member) is guided by the shaft 11 of the main plate 1, and the inner diameter portion of the second assist spring 10 (biasing member) is guided by the shaft 1 m of the main plate 1. Further, the arm portions 9a and 10a of the first assist spring 9 and the second assist spring 10 are locked to the locking portion 1n, and the arm portions 9b and 10b are locked to the shutter base plate 1, and are viewed from the subject side. The arm portions 9a and 10a are charged so that an urging force is generated in the clockwise direction.

  Further, shafts 1o, 1p, 1q, and 1r are erected on the shutter base plate 1. The shafts 1o and 1p have holes 22e and 22f of the first assist spring regulating member 22 (regulating member), and the shafts 1q and 1r have holes 23e and 23f of the second assist spring regulating member 23 (regulating member), respectively. It is mated. The assist spring restricting members 22 and 23 are guided by the shafts 1o, 1p, 1q, and 1r, and can move in the direction of the image sensor 403 within a range limited by the cover 24 and the shutter base plate 1. An inner diameter portion of the compression spring 25 is guided and attached to the shafts 1o and 1q, and the assist spring regulating member 22 is biased toward the subject side.

  Here, with reference to FIG. 3, the structure of the 1st cam gear 15 and the 2nd cam gear 16 (cam member) is demonstrated. FIG. 3 is a front view of the first cam gear 15 and the second cam gear 16 as viewed from the image sensor 403 side. Since the first cam gear 15 and the second cam gear 16 have the same shape, they are collectively described as reference numerals in FIG.

  The cam groove 15c of the first cam gear 15 (cam member) includes a first idle drive cam region 15d (first angle range), a second idle drive cam region 15f (second angle range), and The blade drive cam region 15e (third angle range) has three regions. The first idling drive cam region 15d is formed on a concentric circle with the cam gear shaft 15a, and is a region for holding the first blade unit 2 in the unfolded state via the cam engagement pin 11b. The second idling drive cam region 15f is formed on a concentric circle with the cam gear shaft 15a and is a region for holding the first blade unit 2 in a superimposed state via the cam engagement pin 11b. The blade drive cam region 15e is formed to connect the first idle drive cam region 15d and the second idle drive cam region 15f, and drives the first blade unit 2 via the cam engagement pin 11b. This is an area for shifting the aperture 1a to the closed state or the open state.

  The cam groove 16c of the second cam gear 16 (cam member) includes a first idling drive cam region 16d (first angle range), a second idling drive cam region 16f (second angle range), and The blade drive cam region 16e (third angle range) has three regions. The first idling drive cam region 16d is a region that is formed concentrically with the cam gear shaft 16a and holds the second blade unit 3 in a superimposed state via the cam engagement pin 12b. The second idling drive cam region 16f is formed on a concentric circle with the cam gear shaft 16a and is a region for holding the second blade unit 3 in the unfolded state via the cam engagement pin 12b. The blade drive cam region 16e is formed to connect the first idle drive cam region 16d and the second idle drive cam region 16f, and drives the second blade unit 3 via the cam engagement pin 12b. This is a region for shifting the aperture 1a to an open state or a closed state.

  As described above, the first cam gear 15 and the second cam gear 16 have the first angular range (states A to D), the second angular range (states D to E), and the first angular range and the first angular range, respectively. The rotation is possible in a third angle range (states E to F) between the two angle ranges. The first cam gear 15 and the second cam gear 16 move the first blade unit 2 and the second blade unit 3 by rotation in the third angle range, respectively. That is, the first cam gear 15 and the second cam gear 16 rotate without moving the first blade unit 2 and the second blade unit 3 in the first angle range and the second angle range. On the other hand, the first cam gear 15 and the second cam gear 16 rotate so as to move the first blade unit 2 and the second blade unit 3 in the third angle range.

  As will be described later, the first assist spring 9 and the second assist spring 10 rotate the first cam gear 15 and the second cam gear 16 so as to rotate from the first angle range toward the third angle range. Energize each. Further, as will be described later, the assist spring regulating members 22 and 23 are the first cam gears of the first assist spring 9 and the second assist spring 10 in at least a part of the first angular range (states A to B). The urging to the 15 and the second cam gear 16 is restricted.

  As shown in FIG. 1, the motors 19 and 20 are attached to a motor plate 21. The motor plate 21 is screwed to the holder member 17 with screws 14. A pinion gear 18 is attached to the output shafts 19a and 20a of the motors 19 and 20. The pinion gear 18 passes through the hole 17e of the holder member 17 and engages with the gear portions 15b and 16b of the first cam gear 15 and the second cam gear 16 to thereby apply torque from the motors 19 and 20 to the first cam gear 15. Transmission is made to the cam gear 15 and the second cam gear 16, respectively. The motors 19 and 20 are stepping motors that are driven by switching the energization state of the coil according to a predetermined time interval.

  Next, the operation of the focal plane shutter 113 (shutter device) will be described with reference to FIGS. 4 and 5 (a) to 5 (g). FIG. 4 is a diagram showing the relationship between the moving position of the blade unit (shutter blade) of the focal plane shutter 113 and the rotation angles of the first cam gear 15 and the second cam gear 16. States A to F shown in FIG. 4 correspond to states A to F shown in FIG. 3 shows cam engaging pins of the first drive member 11 and the second drive member 12 at the rotation angles of the first cam gear 15 and the second cam gear 16 corresponding to the states A to F in FIG. 11b and 12b have shown the position which each engages with the cam grooves 15c and 16c.

  FIGS. 5A to 5G show the first cam gear 15 and the second cam gear 16, the first assist spring 9 and the second assist spring 10, and assist spring regulating members 22 and 23. It is the schematic which shows the relationship. Each figure is a plan view of the first cam gear 15 and the second cam gear 16 as seen from the radial direction. The movement of the first cam gear 15 and the second cam gear 16 in the right direction in the figure indicates the left rotation of the first cam gear 15 and the second cam gear 16 as viewed from the subject side. On the other hand, the leftward movement of the first cam gear 15 and the second cam gear 16 in the drawing indicates the right rotation of the first cam gear 15 and the second cam gear 16 as viewed from the subject side. Further, the upper direction in the figure indicates the subject direction, and the lower direction indicates the direction of the image sensor 403. 5A to 5G, the first cam gear 15, the first assist spring 9, the assist spring restricting member 22, the second cam gear 16, the second assist spring 10, And the relationship of each operation | movement and arrangement | positioning with the assist spring control member 23 is mutually the same. For this reason, each reference code is shown together and described with the same figure.

<Standby standby state (spring lock state)>
FIG. 6 is a diagram illustrating a standby state (photographing standby state) of the focal plane shutter 113 before photographing. In the photographing standby state, the first cam gear 15 and the second cam gear 16 are at the angles of the state A shown in FIGS. At this time, as shown in FIG. 6, the first blade unit 2 is in a deployed state, the second blade unit 3 is in a superimposed state, and the aperture 1a is closed by the blades 2a, 2b, and 2c.

  Further, as shown in FIG. 6, the spring contact portions 22 d and 23 d of the assist spring regulating members 22 and 23 are disposed outside the outer diameters of the first cam gear 15 and the second cam gear 16. Therefore, the assist spring restricting members 22 and 23 and the cam gears 15 and 16 are between the cam surfaces provided on the assist spring restricting members 22 and 23 and the pressing portions 15 g and 16 g provided on the cam gears 15 and 16. Only interfere. In the present embodiment, the assist spring regulating members 22 and 23 are provided with first cam surfaces 22a and 23a, second cam surfaces 22b and 23b, and third cam surfaces 22c and 23c as cam surfaces. ing.

  FIG. 5A is a schematic diagram when the first cam gear 15 and the second cam gear 16 are at the angle of the state A. FIG. As shown in FIG. 5A, the assist spring restricting members 22 and 23 are urged upward (subject direction, object side) in FIG. With such a configuration, the positions of the assist spring regulating members 22 and 23 in the upward direction in FIG. 5A are regulated and determined by the cover 24. The spring contact portions 22d and 23d of the assist spring regulating members 22 and 23 are in contact with the assist spring arm portions 9a and 10a on the movement locus of each assist spring. In this state, the spring contact portions 22d and 23d receive the urging force in the left direction in FIG. 5A (the right rotation direction in FIG. 6) from the first assist spring 9 and the second assist spring 10. Take it.

  The assist spring regulating members 22 and 23 are fitted to the shafts 1o and 1q and the shafts 1p and 1r (not shown), respectively, and only in the downward direction (the image sensor 403 direction, the image plane side) in FIG. It is in a movable state. For this reason, the first assist spring 9 and the second assist spring 10 stop in a charged state. That is, in at least a part of the first angle range (state A, photographing standby state), the assist spring regulating members 22 and 23 charge the assist springs and attach them to the first cam gear 15 and the second cam gear 16. The motors 19 and 20 are stopped while the force is regulated. At this time, the first cam gear 15 and the second cam gear 16 do not receive the urging force in the left direction in FIG. 5A (the right rotation direction in FIG. 6). For this reason, it can be stopped by the cogging torque of the motors 19 and 20, and it can stand by while maintaining the angle of the state A without energizing the motors 19 and 20. In such a photographing standby state, the focal plane shutter 113 waits for the switch (SW1) 498 to be turned on. In the imaging apparatus 400 (see FIG. 8), when the switch (SW1) 498 is turned on, a distance measuring unit (focus detection unit) (not shown) measures the distance to the subject, and the lens control unit 491 drives the imaging lens 401. Perform shooting preparation operations such as focusing.

<Release spring lock>
FIGS. 5B, 5C, and 5D are schematic diagrams showing how the first cam gear 15 and the second cam gear 16 shift from the state A to the angle of the state B. FIG. . When switch (SW2) 499 is turned on (when a photographing start instruction is received from the photographer), motors 19 and 20 are driven. When the first cam gear 15 and the second cam gear 16 start to rotate in the right rotation direction in FIG. 6, as shown in FIG. 5B, the cam gear pressing portions 15g, 16g are the assist spring restricting members 22, 23. The first cam surfaces 22a and 23a provided on the first and second cam surfaces 22a and 23a come into contact. The assist spring regulating members 22 and 23 receive a downward force (in the direction of the image sensor 403) in FIG. 5B from the pressing portions 15g and 16g of the first cam gear 15 and the second cam gear 16. The assist spring regulating members 22 and 23 that have received a downward force (in the direction of the image sensor 403) in FIG. 5B are in a state in which the spring contact portion 22d is retracted from the movement locus of the assist spring arm portions 9a and 10a. Move to displace.

  When the spring contact portion 22d is completely retracted from the movement trajectory of the assist spring arm portions 9a and 10a, the assist spring arm portions 9a and 10a are spring-engaged portions 15i and 16i of the first cam gear 15 and the second cam gear 16. Abuts on the (projection). The assist spring arm portions 9a and 10a urge the first cam gear 15 and the second cam gear 16 in the left direction in FIG. 5B (the right rotation direction in FIG. 6). In this way, when receiving a shooting start instruction from the photographer, the motors 19 and 20 start to rotate the first cam gear 15 and the second cam gear 16. The assist spring restricting members 22 and 23 release the restriction of the first assist spring 9 and the second assist spring 10 according to the rotation of the motors 19 and 20.

  When further rotated, the state shown in FIG. 5C is obtained, and the pressing portions 15g, 16g of the first cam gear 15 and the second cam gear 16 are brought into contact with the second cam surface 22b provided on the assist spring restricting members 22, 23. Touch. The pressing portions 15g and 16g maintain the state where the spring contact portions 22d and 23d of the assist spring restricting members 22 and 23 are retracted from the movement locus of the assist spring arm portions 9a and 10a.

  When the first cam gear 15 and the second cam gear 16 reach the angle of the state B shown in FIG. 5D, the first cam gear 15 and the second cam gear 16 are driven by the energization holding force of the motors 19 and 20. Stop. At this time, when the pressing portions 15g and 16g of the first cam gear 15 and the second cam gear 16 and the respective cam surfaces of the spring restricting member 22 are stopped, the motors 19 and 20 start moving. The load due to contact can be eliminated, and variations in exposure operation can be suppressed. Since the motors 19 and 20 are stepping motors, the movement amount and time from the state A to the state B can be accurately controlled. For this reason, when the motors 19 and 20 start to move, an appropriate exposure amount can be obtained by providing a delay suitable for the shutter speed. The image sensor 403 performs reset scanning after a predetermined time from when the switch (SW2) 499 is turned on, and starts accumulation of each row.

  As described above, in the present embodiment, the assist spring restricting members 22 and 23 can shift to the first state, the second state, and the third state in the first angle range (states A to D). is there. In the first state, the assist spring restricting members 22 and 23 are on the movement locus of the first assist spring 9 and the second assist spring 10, and the urging force of the first assist spring 9 and the second assist spring 10 is present. It is a state (FIG.5 (b)) which receives. The second state is a state where the first assist spring 9 and the second assist spring 10 are retracted from the movement locus (FIG. 5C). The third state is on the movement locus of the first assist spring 9 and the second assist spring 10 and is not subjected to the urging force of the first assist spring 9 and the second assist spring 10 (FIG. 5 ( d)).

  Preferably, the first cam gear 15 and the second cam gear 16 have protrusions (spring locking portions 15i and 16i). The assist spring restricting members 22 and 23 move from the first state or the third state to the second state by moving in the optical axis direction when the protrusions abut. Also preferably, the assist spring restricting members 22, 23 have first cam surfaces 22a, 23a, second cam surfaces 22b, 23c, and third cam surfaces 22c, 23c. The first cam surfaces 22a and 23a are in contact with the first cam gear 15 and the second cam gear 16, and shift from the first state to the second state. The second cam surfaces 22b and 23b are in contact with the first cam gear 15 and the second cam gear 16, and maintain the second state. The third cam surfaces 22c and 23c are in contact with the first cam gear 15 and the second cam gear 16, and shift from the second state to the third state.

<Exposure running>
After the first cam gear 15 and the second cam gear 16 are stopped at the angle of the state B, the first cam gear 15 and the second cam gear 16 are driven by the driving force of the motors 19 and 20 and the first assist spring 9 and the second cam gear 16. In response to the urging force of the second assist spring 10, it is driven in the clockwise direction of FIG. 6. As a result, the first cam gear 15 and the second cam gear 16 start accelerating in the first idle cam regions 15d and 16d shown in FIGS.

  When the first cam gear 15 and the second cam gear 16 reach the angle of the state C, the assist spring arm portions 9a and 10a come into contact with the locking portion 1n of the shutter base plate 1, and the first cam gear 15 and the second cam gear 16 Separates from the first assist spring 9 and the second assist spring 10. Thereby, the state shifts from the state D to the blade drive cam regions 15e and 16e in the state E.

  In the blade drive cam regions 15e and 16e, the first cam gear 15 drives the first blade unit 2 via the cam engaging pin 11b, and the second cam gear 16 receives the second cam gear 16 via the cam engaging pin 12b. The blade unit 3 is driven. Accordingly, the blades 2a, 2b, and 2c that have closed the aperture 1a open the aperture 1a (the first blade unit 2 changes from the closed state to the open state). Further, the blades 3a, 3b, and 3c that have opened the aperture 1a close the aperture 1a (the second blade unit 3 changes from the open state to the closed state). As described above, the first blade unit 2 and the second blade unit 3 expose the image sensor 403 at the shutter speed determined by the photographer.

  Thus, in the present embodiment, the first angular range (first idle driving cam regions 15d and 16d) includes the first partial region (states AB) and the second partial region (states BC). ) And the third partial region (states C to D). In the first partial region, the assist spring restricting members 22 and 23 restrict the urging of the first assist spring 9 and the second assist spring 10 to the first cam gear 15 and the second cam gear 16. The first cam gear 15 and the second cam gear 16 are a first assist spring that assists the driving force of the motors 19 and 20 and the rotation of the first cam gear 15 and the second cam gear 16 in the second partial region. 9 and the urging force of the second assist spring 10 rotate. The first cam gear 15 and the second cam gear 16 are driven by the driving force of the motors 19 and 20 without being biased by the first assist spring 9 and the second assist spring 10 in the third partial region. Rotate.

<Exposure run complete>
When the first cam gear 15 and the second cam gear 16 pass the angle of the state E, the blade drive cam regions 15e and 16e shown in FIGS. 3 and 4 shift to the second idle cam regions 15f and 16f. When the first cam gear 15 and the second cam gear 16 reach the angle of the state F, the movable end portions 15h and 16h of the first cam gear 15 and the second cam gear 16 contact the contact portions 17b and 17d of the holder member 17, respectively. Touch. Thereby, the drive of the 1st cam gear 15 and the 2nd cam gear 16 in the clockwise rotation direction stops.

  At this time, as shown in FIG. 7, the first blade unit 2 is in a superimposed state, the second blade unit 3 is in a deployed state, and the aperture 1a is closed by the blades 3a, 3b, and 3c. FIG. 7 is a diagram showing a state of completion of exposure travel (completion of blade travel). The imaging apparatus 400 can start a still image reading scan of the imaging element 403 after a predetermined time.

<Blade return travel-spring charge (spring lock operation)>
After waiting for a certain time in the state F, the first cam gear 15 and the second cam gear 16 are driven in the left rotation direction in FIG. Then, the first cam gear 15 and the second cam gear 16 pass through the blade drive cam regions 15d and 16d shown in FIGS. 3 and 4, and the first blade unit 2 is deployed, and the second blade unit 3 is moved. Return to the superimposed state. When further rotated, the locking portions 15i and 16i of the first cam gear 15 and the second cam gear 16 come into contact with the assist spring arm portions 9a and 10a at the angle of the state C, and the assist springs 9 and 10 are charged.

  FIGS. 5E, 5F, and 5G show the first cam gear 15 and the second cam gear in the process of charging the first assist spring 9 and the second assist spring 10, respectively. It is the schematic which shows a mode that 16 passes through the state B and transfers to the angle of the state A. FIG. When the first cam gear 15 and the second cam gear 16 pass through the state B, as shown in FIG. 5 (e), the cam gear pressing portions 15g, 16g are the second provided on the assist spring restricting members 22, 23, respectively. The cam surface 22c. The assist spring restricting members 22 and 23 receive a downward force (in the direction of the image sensor 403) in FIG. 5E from the cam gear pressing portions 15g and 16g. The spring regulating members 22 and 23 that have received a downward force (in the direction of the image sensor 403) in FIG. 5E are in a state in which the spring contact portion 22d is retracted from the movement locus of the assist spring arm portions 9a and 10a. Moving. Therefore, the assist spring arm portions 9a and 10a pass on the movement trajectory without contacting the spring contact portions 22d and 23d.

  When the cam gear pressing portions 15g and 16g are separated from the assist spring restricting members 22 and 23, the spring restricting members 22 and 23 are urged upward (in the subject direction) in FIG. Therefore, as shown in FIG. 5G, the spring contact portion 22d presses the assist spring arm portions 9a and 10a in the upward direction (subject direction) in the drawing. At this time, the spring locking portions 15i and 16i of the first cam gear 15 and the second cam gear 16 regulate the position of the assist spring arm portions 9a and 10a in the upward direction (subject direction) in the figure. For this reason, the assist spring arm portions 9a and 10a can get over the assist spring restricting members 22 and 23 without moving in the upward direction (subject direction) in FIG.

  When the first cam gear 15 and the second cam gear 16 exceed the angle of the state A, the spring contact portion 22d moves on the movement locus of the assist spring arm portions 9a and 10a. The spring contact portion 22d receives the urging force in the left direction in FIG. 5G (the right rotation direction in FIG. 7) from the first assist spring 9 and the second assist spring 10. Further, the movable end portions 15h, 16h of the first cam gear 15 and the second cam gear 16 abut on the abutting portions 17a, 17c of the holder member 17, and the first cam gear 15 and the second cam gear 16 are rotated in the counterclockwise direction. Stop driving. The first cam gear 15 and the second cam gear 16 are held at the angle of state A by the cogging torque of the motors 19 and 20. That is, the imaging apparatus 400 returns to the shooting standby state shown in FIG. 5A and waits for the next release.

  As described above, in the present embodiment, the first assist spring 9 and the second assist spring 10 that assist the acceleration of the cam gears 15 and 16 by the assist spring restricting members 22 and 23 are mechanically held in a charged state. . Thereby, the release time lag can be shortened while suppressing the power consumption in the shooting standby state.

(Second Embodiment)
Next, an imaging device according to a second embodiment of the present invention will be described. First, the configuration of the focal plane shutter 113a in the present embodiment will be described with reference to FIGS. FIG. 9 is an exploded perspective view of the focal plane shutter 113a of the present embodiment as viewed from the subject side. FIG. 10 is an exploded perspective view of the focal plane shutter 113a as viewed from the image sensor 403 side. FIG. 11 is a front view of the first cam gear 65 and the second cam gear 66 (cam member) as viewed from the subject side. FIG. 12 is a perspective view of the first drive member 61 and the second drive member 62. FIG. 13 is a front view of the first assist gear 63 and the second assist gear 64 (transmission member) as seen from the subject side.

  A cover plate 58 is attached to the shutter base plate 51 on the subject side. Between the shutter base plate 51 and the cover plate 58, a first blade unit 52 comprising blades 52a, 52b and 52c and blade arms 52d and 52e, and a first blade unit comprising blades 53a, 53b and 53c and blade arms 53d and 53e. Two blade units 53 are installed. Apertures 51a and 58a (openings) are formed in the shutter base plate 51 and the cover plate 58, respectively. Each of the first blade unit 52 and the second blade unit 53 is a light shielding member that can move between a closed state in which the aperture 51a is closed and an open state in which the aperture 51a is opened. Shafts 51b and 51c are erected on the image pickup element 403 side of the shutter base plate 51, and a first drive member 61 is rotatably attached to the shaft 51b and a second drive member 62 is rotatably attached to the shaft 51c. ing.

  The shutter base plate 1 is provided with shafts 51d and 51e. The shaft 51d is engaged with the hole 65a of the first cam gear 65, and the shaft 51e is engaged with the hole 66a of the second cam gear 66. Supported as possible. Further, shafts 51f, 51g, 51h, 51i are erected on the subject side of the shutter base plate 51, the first blade unit 52 is disposed on the shaft 51f, 51g, and the second is disposed on the shaft 51h, 51i. Each blade unit 53 is rotatably attached.

  The first drive member 61 is rotatable by fitting the hole 61a and the shaft 51b of the shutter base plate 51. The first cam engagement pin 61b of the first drive member 61 is disposed so as to be able to contact the first blade drive region 65c of the first cam gear 65, and the second cam engagement pin 61c is the second cam engagement pin 61c. It is arranged so as to be able to contact the blade drive region 65d. Then, according to the rotation of the first cam gear 65, the first cam engagement pin 61b is along the first blade drive region 65c, or the second cam engagement pin 61c is along the first blade drive region 65d. Thus, the first drive member 61 is driven. Thus, the first drive member 61 is a drive member that can rotate in conjunction with the first blade unit 51.

  The second drive member 62 is rotatable by fitting the hole 62a with the shaft 51c of the shutter base plate 51. The first cam engagement pin 62b of the second drive member 62 is disposed so as to be able to contact the first blade drive region 66c of the second cam gear 66, and the second cam engagement pin 62c is the second cam engagement pin 62c. The blade drive area 66d is arranged so as to be able to come into contact therewith. Then, according to the rotation of the second cam gear 66, the first cam engagement pin 62b is along the first blade drive region 66c, or the second cam engagement pin 62c is along the second blade drive region 66d. Thus, the second drive member 62 is driven. Thus, the first drive member 61 and the second drive member 62 are drive members that can rotate in conjunction with the second blade unit 52.

  The first blade unit 52 includes two blade arms 52d and 52e and three blades 52a, 52b and 52c. The holes 52f and 52g of the two blade arms 52d and 52e are pivotally attached to the shafts 51f and 51g, respectively, on the subject side of the shutter base plate 51. The three blades 52a, 52b, and 52c are sequentially pivoted via the connecting shaft 7 toward the other ends of the blade arms 52d and 52e. A hole 52h is formed in the blade arm 52, and the drive pin 61d of the first drive member 61 is engaged with the hole 52h. Thereby, according to rotation of the 1st drive member 61, it can shift to a closed state where blades 52a, 52b, and 52c cover aperture 51a of shutter base plate 51, and an open state where it retreats from aperture 51a, respectively. .

  The second blade unit 53 includes two blade arms 53d and 53e and three blades 53a, 53b, and 53c. The holes 53f and 53g of the two blade arms 53d and 53e are pivotally attached to the shafts 51h and 51i on the subject side of the shutter base plate 51, respectively. The three blades 53a, 53b, 53c are sequentially pivoted via the connecting shaft 7 toward the other ends of the blade arms 53d, 53e. A hole 53h is formed in the blade arm 53, and the drive pin 62d of the second drive member 62 is engaged with the hole 53h. Thereby, according to rotation of the 2nd drive member 62, it can shift to the closed state in which the wing | blade 53a, 53b, 53c covers the aperture 51a of the shutter base plate 51, and the open state which retracts from the aperture 51a, respectively.

  The first assist gear 63 is pivotally supported by a shaft 51 j on the image pickup device 403 side of the shutter base plate 51 so as to be rotatable, and the axial direction is restricted by the first presser plate 67. The gear part 63b of the first assist gear 63 is a toothless gear and can mesh with the second gear part 65e of the first cam gear 65 depending on the rotational position. The first assist spring 59 (biasing member) is guided by the outer shape of the first assist gear 63. The first assist spring 59 has a first arm 59 a locked to the shutter base plate 51 and a second arm 59 b locked to the locking portion 63 a of the first assist gear 63. And charged so that an urging force is generated in the clockwise direction. At this time, the first assist gear 62 is held in a state in which the locking portion 63a comes into contact with the fixed end 51l erected on the shutter base plate and the first assist spring 59 is charged.

  The second assist gear 63 is pivotally supported by a shaft 51k on the image pickup device 403 side of the shutter base plate 51 so as to be rotatable, and the axial direction thereof is restricted by the second presser plate 68. The gear part 64b of the second assist gear 64 is a toothless gear, and can mesh with the second gear part 66e of the second cam gear 66 depending on the rotational position. The second assist spring 60 (biasing member) is guided by the outer shape of the second assist gear 64. The second assist spring 60 has a first arm 60 a locked to the shutter base plate 51 and a second arm 60 b locked to the locking portion 64 a of the second assist gear 64, as viewed from the image sensor 403 side. And charged so that an urging force is generated in the clockwise direction. At this time, the second assist gear 64 is held in a state in which the locking portion 64a comes into contact with the fixed end 51m erected on the shutter base plate and the assist spring 60 is charged.

  Here, referring to FIGS. 11 to 13, the first cam gear 55, the second cam gear 56, the first drive member 61, the second drive member 62, the first assist gear 63, and the second The configuration of the assist gear 64 will be described. Since the first cam gear 65 and the second cam gear 66, and the first assist gear 63 and the second assist gear 64 have the same shape, the reference numerals in FIGS. 11 and 13 are collectively shown. Yes.

  The first cam gear 65 has a first idling cam region 65f1 with which the first cam engagement pin 61b abuts and holds the first blade unit 52 in a deployed state via the drive pin 61d. At this time, when the first drive member 61 tries to rotate in the clockwise direction when viewed from the image sensor 403 side, the third cam engagement pin 61e is regulated by the first regulation cam surface 65f2 of the first cam gear 65. Therefore, the first blade unit 52 is held in a deployed state at a predetermined position. The first cam gear 65 has a second idling cam region 65g1 with which the second cam engagement pin 61c abuts and holds the first blade unit 52 in a superimposed state via the drive pin 61d. At this time, if the first drive member 61 tries to rotate in the left rotation direction when viewed from the image sensor 403 side, the second cam engagement pin 61c is restricted by the second restriction cam surface 65g2 of the first cam gear 65. Therefore, the first blade unit 52 is held in a superimposed state at a predetermined position. The first cam gear 65 has a first blade drive region 65c and a second blade drive region 65d. In the first blade drive region 65c, the first cam gear 65 abuts on the first cam engagement pin 61b, drives the first blade unit 52 via the drive pin 61d, and opens the aperture 51a from the closed state. Transition to the state. In the second blade drive region 65d, the first cam gear 65 contacts the second cam engagement pin 61c, drives the first blade unit 52 via the drive pin 61d, and closes the aperture 51a from the open state. Transition to the state. The first blade driving area 65c and the first idle running cam area 65f1, the first blade driving area 65c and the second idle running cam area 65g1, the second blade driving area 65d and the second regulating cam surface 65g2 Each is connected smoothly. For this reason, driving of the blades can be started without generating a large impact.

  The first cam gear 65 has a second gear portion 65e that is connected to the gear portion 63b of the first assist gear 63 in accordance with the rotational phase. As will be described later, when the first cam gear 65 rotates counterclockwise as viewed from the subject side, the second gear portion 65e of the first cam gear 65 and the gear portion 63b of the first assist gear 63 Begins to concatenate. Thereafter, the pushing cam surface 65h of the first cam gear 65 comes into contact with the cam surface 63c of the first assist gear 63, and the first assist gear 63 is driven to rotate. When the first cam gear 65 further rotates, the assist holding cam surface 65i that is connected to the cam surface 65h smoothly and is formed concentrically with the hole 65a contacts the cam surface 63c of the first assist gear 63. At this time, the first assist gear 63 is urged in the left rotation direction when viewed from the subject side by the first assist spring 59, but the force exerted in the rotation direction of the first cam gear 65 is the assist holding cam surface 65i. And the frictional force generated between the cam surface 63c and the cam surface 63c. For this reason, the first cam gear 65 is not rotated by the biasing force of the first assist spring 59.

  The second cam gear 66 has a first idle cam region 66f1 with which the first cam engagement pin 62b comes into contact and holds the second blade unit 53 in an overlapped state via the drive pin 62d. At this time, when the second drive member 62 tries to rotate in the right rotation direction when viewed from the image sensor 403 side, the third cam engagement pin 62e is regulated by the first regulation cam surface 66f2 of the second cam gear 66. Therefore, the second blade unit 53 is held in a superimposed state at a predetermined position. The second cam gear 66 has a second idling cam region 66g1 with which the second cam engagement pin 62c abuts and holds the second blade unit 53 in a deployed state via the drive pin 62d. At this time, when the second driving member 62 tries to rotate in the left rotation direction when viewed from the image sensor 403 side, the second cam engaging pin 62c is regulated by the second regulating cam surface 66g2 of the second cam gear 66. Therefore, the second blade unit 53 is held in a deployed state at a predetermined position. The second cam gear 66 has a first blade driving region 66c and a second blade driving region 66d. In the first blade driving region 66c, the second cam gear 66 abuts on the first cam engaging pin 62b, drives the second blade unit 53 via the driving pin 62d, and closes the aperture 51a from the open state. Transition to the state. In the second blade driving region 66d, the second cam gear 66 abuts on the second cam engaging pin 62c, drives the second blade unit 53 via the driving pin 62d, and opens the aperture 51a from the closed state. Transition to the state. The first blade driving area 66c and the first idle running cam area 66f1, the first blade driving area 66c and the second idle running cam area 66g1, the second blade driving area 66d and the second regulating cam surface 66g2 Each is connected smoothly. For this reason, driving of the blades can be started without generating a large impact.

  The second cam gear 66 has a second gear portion 66e that is connected to the gear portion 64b of the second assist gear 64 in accordance with the rotational phase. As will be described later, when the second cam gear 66 rotates counterclockwise as viewed from the subject side, the second gear portion 66e of the second cam gear 66 and the gear portion 64b of the second assist gear 64 are moved. Start linking. Thereafter, the pushing cam surface 66h of the second cam gear 66 comes into contact with the cam surface 64c of the second assist gear 64, and the second assist gear 64 is driven to rotate. When the second cam gear 66 further rotates, the assist holding cam surface 66i that is smoothly connected to the cam surface 66h and formed concentrically with the hole 66a abuts against the cam surface 64c of the second assist gear 64. At this time, the second assist gear 64 is urged in the left rotation direction when viewed from the subject side by the assist spring 60, but the force exerted in the rotation direction of the second cam gear 66 is the assist holding cam surface 66i and the cam. The friction force generated between the surfaces 64c is small. For this reason, the second cam gear 66 is not rotated by the biasing force of the assist spring 60.

  As shown in FIG. 10, the motors 69 and 70 are attached to the motor plate 71, and the motor plate 71 is fixed to the shutter base plate 51. A pinion gear 72 is attached to the output shaft 69 a of the motor 69. The pinion gear 72 is engaged with the gear portions 65 b and 66 b of the cam gears 65 and 66, thereby transmitting torque from the motors 69 and 70 to the cam gears 65 and 66. The motors 69 and 70 are stepping motors that are driven by switching the energization state of the coil according to a predetermined time interval.

  Next, the operation of the focal plane shutter 113a in the present embodiment will be described with reference to FIGS. 14 to 18 are diagrams showing the relationship between the movement position of the blade unit of the focal plane shutter 113a of the imaging apparatus 400 and the rotation angle of the cam gears 65 and 66, as viewed from the subject side. 14 (a), 15 (a), 16 (a), 17 (a), and 18 (a) show the first blade unit 52, the first assist spring 59, the first The state at the time of imaging | photography of the drive member 61, the 1st assist gear 63, and the 1st cam gear 65 is shown. 14B, FIG. 15B, FIG. 16B, FIG. 17B, and FIG. 18B show the second blade unit 53, the assist spring 60, and the second drive member 62. The state of the second assist gear 64 and the second cam gear 66 during photographing is shown.

<Standby standby state (spring lock state)>
FIGS. 14A and 14B are views showing a standby state before photographing of the focal plane shutter 113a in the present embodiment. The first cam gear 65 and the second cam gear 66 are at an angle of state A shown in FIG. As shown in FIG. 14A, the first blade unit 52 is in a deployed state, the second blade unit 53 is in a superimposed state, and the aperture 51a is closed by the blades 52a, 52b, and 52c.

  In the first drive member 61 and the second drive member 62, the first cam engagement pins 61b and 62b are in contact with the first idle running cam regions 65f1 and 66f1. In the first drive member 61 and the second drive member 62, the third cam engagement pins 61e and 62e are restricted from rotating in the left rotation direction when viewed from the subject side by the first restriction cam surfaces 65f2 and 66f2. Therefore, the blade units 52 and 53 are held at predetermined positions.

  In the first assist spring 59 and the second assist spring 60, the arms 59a and 60a are fixed to the shutter base plate, and the arms 59b and 60b are engaged with the first assist gear 63 and the second assist gear 64 in a charged state. It abuts against the stops 63a and 64a. For this reason, the first assist spring 59 and the second assist spring 60 respectively bias the first assist gear 63 and the second assist gear 64 in the counterclockwise direction when viewed from the subject side. In the first assist gear 63 and the second assist gear 64, the cam surfaces 63c and 64c are in contact with the assist holding cam surfaces 65i and 66i. At this time, the first assist gear 63 and the second assist gear 64 are urged in the left rotation direction as viewed from the subject side by the first assist spring 59 and the second assist spring 60. However, the force exerted in the rotation direction of the first cam gear 65 and the second cam gear 66 is smaller than the frictional force generated between the assist holding cam surfaces 65i, 66i and the cam surfaces 63c, 64c. For this reason, the first cam gear 65 and the second cam gear 66 are not rotated by the urging force of the first assist spring 59 and the second assist spring 60. As described above, the first cam gear 65 and the second cam gear 66 can be stopped by the cogging torque of the motors 69 and 70, and can stand by while maintaining the angle of the state A without energizing the motors 69 and 70. Can do.

  In this standby state, the focal plane shutter 113a waits for the switch (SW1) 498 to be turned on. In the imaging apparatus 400 (see FIG. 8), when the switch (SW1) 498 is turned on, the distance measuring unit (not shown) measures the distance to the subject, the lens control unit 491 drives the photographing lens to perform focusing, and the like. Perform the shooting preparation operation.

<Release spring lock>
FIGS. 15A and 15B are diagrams showing how the first cam gear 65 and the second cam gear 66 shift from the state A to the state B shown in FIG. When the switch SW2 (499) is turned on, the first cam gear 65 and the second cam gear 66 start to rotate in the clockwise direction in FIG. At this time, as shown in FIGS. 15A and 15B, the cam surfaces 63 c and 64 c of the first assist gear 63 and the second assist gear 64 correspond to the first cam gear 65 and the second cam gear 66. It begins to abut against the push cams 65h, 66h. A biasing force is applied to the first cam gear 65 and the second cam gear 66 in the direction of clockwise rotation when viewed from the subject side.

  When the angle of state B is reached as shown in FIGS. 15A and 15B, the first cam gear 65 and the second cam gear 66 may be stopped by the energization holding force of the motors 69 and 70. . In state B, the first cam gear 65 and the second cam gear 66 are stopped. Therefore, the push cams 65h, 66h and the cam surfaces 63c, 64c of the first assist gear 63 and the second assist gear 64 from the assist holding cam surfaces 65i, 66i of the first cam gear 65 and the second cam gear 66. The load of movement due to friction can be eliminated. As a result, it is possible to suppress variations in the exposure operation.

  Further, since the motors 69 and 70 are stepping motors, it is possible to accurately control the movement amount and time from the state A to the state B. For this reason, it is possible to obtain an appropriate exposure amount by providing a delay suitable for the shutter speed when the motors 69 and 70 start to move. The image sensor 403 performs reset scanning a predetermined time after the switch (SW2) 499 is turned on, and starts accumulation of each row.

<Exposure running>
When the first cam gear 65 and the second cam gear 66 are further rotated in the clockwise direction, as shown in FIGS. 16A and 16B, the third gear portions 65e and 66e are The gear portions 63b and 64b of the assist gear 63 and the second assist gear 64 are connected. The first cam gear 65 and the second cam gear 66 receive the driving force of the motors 69 and 70 and the urging force of the first assist spring 59 and the second assist spring 60, and are shown in FIG. Acceleration is started at one idle cam region 65f1 and 66f1. When the first cam gear 65 and the second cam gear 66 reach the angle of the state C, as shown in FIGS. 17A and 17B, the first assist gear 63 and the second assist gear 64 are locked. The parts 63a and 64a abut against fixed ends 51l and 51m provided upright on the shutter base plate. Then, the first cam gear 65 and the second cam gear 66 are disengaged from the first assist gear 63 and the second assist gear 64, and the state D is shifted to the first blade drive regions 65c and 66c in the state E. To do.

  In the first blade driving regions 65c and 66c, the first cam gear 65 drives the first blade unit 52 via the first cam engagement pin 61b, and the second cam gear 66 is connected to the cam engagement pin 12b. Then, the second blade unit 53 is driven. Accordingly, the blades 52a, 52b, and 52c that have closed the aperture 51a open the aperture 51a, and the blades 53a, 53b, and 53c that have opened the aperture 51a close the aperture 51a. As described above, the first blade unit 52 and the second blade unit 53 expose the image sensor 403 at the shutter time determined by the photographer.

<Exposure run complete>
When the first cam gear 65 and the second cam gear 66 pass through the angle in the state E, the first cam gear 65 and the second cam gear 66 shift to the second idle running regions 65g1 and 66g1 shown in FIG. At the angle of state F, the movable end portions 65j and 66j of the first cam gear 65 and the second cam gear 66 abut on the abutting portions 77a and 77b of the holder member 77, and the first cam gear 65 and the second cam gear The drive in the clockwise direction of 66 is stopped. The first drive member 61 and the second drive member 62 rotate rightward when viewed from the subject side when the first cam engagement pins 61b and 62b abut on the second idle cam regions 65g1 and 66g1. Directional rotation is regulated. Further, the first drive member 61 and the second drive member 62 rotate counterclockwise as viewed from the subject side when the second cam engagement pins 61c and 62c abut on the second restriction cam surfaces 65g2 and 66g2. Directional rotation is regulated. Accordingly, the first drive member 61 and the second drive member 62 are held at predetermined positions, and the blade units 52 and 53 are also held via the drive pins 61d and 62d, so that reexposure due to bounce does not occur. .

  At this time, as shown in FIGS. 18A and 18B, the first blade unit 52 is in a superimposed state, the second blade unit 53 is in a deployed state, and the aperture 51a has blades 53a, 53b, It is closed by 53c. Therefore, after a predetermined time, the imaging apparatus 400 can start a still image reading scan of the imaging element 403.

<Blade return travel-spring charge (spring lock operation)>
After waiting for a certain time in the state F, the first cam gear 65 and the second cam gear 66 are driven by the motors 69 and 70 in the left rotation direction when viewed from the subject side. Then, the second blade drive regions 65d and 66d abut on the second cam engagement pins 61c and 62c, and drive the first drive member 61 and the second drive member 62 in the clockwise direction. As a result, the first blade unit 52 is returned to the deployed state and the second blade unit 53 is returned to the superimposed state via the drive pins 61d and 62d. When the first cam gear 65 and the second cam gear 66 further rotate, the second gear portions 65e and 66e of the first cam gear 65 and the second cam gear 66 become the first assist gear 63 and the second assist gear 64, respectively. The gear portions 63b and 64b are connected. Then, the first assist spring 59 and the second assist spring 60 are charged via the locking portions 63a and 64a.

  When the first cam gear 65 and the second cam gear 66 pass through the state B shown in FIG. 4, as shown in FIGS. 15A and 15B, the pushing cams 65 h and 66 h become the first assist gear 63. And it contacts the cam surfaces 63c, 64c of the second assist gear 64. When the first cam gear 65 and the second cam gear 66 are further driven in the counterclockwise direction when viewed from the subject side, the assist holding cam surfaces 65i, 66i abut against the cam surfaces 63c, 64c. When the angle of state A is exceeded, the movable end portions 65k, 66k of the first cam gear 65 and the second cam gear 66 abut on the abutting portions 77a, 77b of the holder member, and the first cam gear 65 and the second cam gear 66 stops driving in the counterclockwise direction. At this time, the first assist gear 63 and the second assist gear 64 are urged in the left rotation direction as viewed from the subject side by the first assist spring 59 and the second assist spring 60. However, the force exerted in the rotation direction of the cam gears 65, 66 is smaller than the frictional force generated between the assist holding cam surfaces 65i, 66i and the cam surfaces 63c, 64c. For this reason, the first cam gear 65 and the second cam gear 66 are not rotated by the urging force of the first assist spring 59 and the second assist spring 60. As described above, the first cam gear 65 and the second cam gear 66 can be stopped by the cogging torque of the motors 69 and 70, and can stand by while maintaining the angle of the state A without energizing the motors 69 and 70. Can do. That is, the process returns to the standby state shown in FIG. 14 and waits for the next release.

  As described above, in the present embodiment, the transmission member (the first assist gear 63 and the second assist gear 64) includes the first region (the gear portions 63b and 64b) and the second region (the cam surface 63c, 64c). In the first region of the transmission member, the biasing members (first assist spring 59 and second assist spring 60) bias the cam members (first cam gear 65 and second cam gear 66). The cam member is connected to the cam member in a state, and the urging force from the urging member is transmitted in the rotation direction of the cam member. The transmission member is held by the cam member in the second region without transmitting the urging force from the urging member in the rotation direction of the cam member. The assist holding cam surfaces 65i and 66i of the cam member mechanically hold the biasing member in a charged state via the transmission member. Thereby, the release time lag can be shortened while suppressing the power consumption in the standby state.

  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 Shutter base plate 2 1st blade | wing unit (light-shielding member)
3 Second blade unit (light shielding member)
9 First assist spring (biasing member)
10 Second assist spring (biasing member)
15 First cam gear (cam member)
16 Second cam gear (cam member)
19, 20 Motor 22, 23 Assist spring regulating member (regulating member)
113 Focal plane shutter (shutter device)

Claims (12)

A shutter base plate in which an opening is formed;
A light shielding member movable to a closed state for closing the opening and an open state for opening the opening;
Rotating in the first angular range, the second angular range, and a third angular range between the first angular range and the second angular range, and rotating in the third angular range A cam member for moving the light shielding member by:
A motor that rotationally drives the cam member;
A biasing member that biases the cam member so as to rotate from the first angle range toward the third angle range;
And a regulating member that regulates urging of the urging member to the cam member in at least a part of the first angle range.   In at least a part of the first angle range, the motor is stopped in a state where the regulating member charges the biasing member and regulates the biasing to the cam member. The shutter device according to claim 1. The cam member is
In the first angle range and the second angle range, the light shielding member is rotated without being moved,
3. The shutter device according to claim 1, wherein the shutter device rotates so as to move the light shielding member in the third angle range. 4. The first angular range includes a first partial region, a second partial region, and a third partial region,
In the first partial region, the restricting member restricts the biasing of the biasing member to the cam member,
The cam member is
In the second partial region, the motor rotates with the driving force of the motor and the urging force of the urging member that assists the rotation of the cam member,
4. The shutter device according to claim 1, wherein in the third partial region, the shutter device is rotated by a driving force of the motor without being biased by the biasing member. 5. In the first angle range, the regulating member is
A first state that is on a movement trajectory of the biasing member and receives the biasing force of the biasing member;
A second state in which the urging member is retracted from the movement locus;
5. The shutter device according to claim 4, wherein the shutter device is shiftable to a third state that is on a movement locus of the urging member and that does not receive the urging force of the urging member. 6. The cam member has a protrusion,
6. The restricting member shifts from the first state or the third state to the second state by moving in the optical axis direction when the protrusion comes into contact with the restricting member. The shutter device according to 1. The regulating member is
A first cam surface that abuts the cam member and causes the transition from the first state to the second state;
A second cam surface that contacts the cam member and maintains the second state;
7. The shutter device according to claim 5, further comprising a third cam surface that contacts the cam member and shifts from the third state to the second state. 8. A drive member including a cam engagement pin;
The shutter device according to claim 1, wherein the cam member is engaged with the cam engagement pin and is driven to rotate by the motor. A shutter base plate in which an opening is formed;
A light shielding member movable to a closed state for closing the opening and an open state for opening the opening;
A motor,
A drive member having a cam engagement pin and rotatable in conjunction with the light shielding member;
A cam that engages with the cam engagement pin and is rotatable in a first angle range, a second angle range, and a third angle range between the first angle range and the second angle range Members,
A biasing member that biases the cam member so as to rotate from the first angle range and the third angle range toward the second angle range;
A first region that is connected to the cam member in a state in which the biasing member biases the cam member, and transmits a biasing force from the biasing member in the rotation direction of the cam member; A transmission member having a second region that is held by the cam member without transmitting the urging force from the member in the rotational direction of the cam member;
The first angle range is a range in which the cam member can be moved without moving the light shielding member,
The second angle range is a range in which the cam member can be moved between the closed state and the open state of the light shielding member,
The shutter device according to claim 3, wherein the third angle range is different from the first angle range in which the cam member can be moved without moving the light shielding member. A shutter device according to any one of claims 1 to 9,
An image pickup apparatus comprising: an image pickup device that photoelectrically converts an optical image formed through an image pickup optical system.   The imaging device according to claim 10, wherein in the photographing standby state, the regulating member charges the urging member to regulate urging to the cam member, and the motor is stopped.   The said motor starts the said rotational drive of the said cam member when the imaging | photography start instruction | indication from a photographer is received, The said limitation member cancels | releases the regulation of the said urging | biasing member according to rotation of this motor. Item 12. The imaging device according to Item 10 or 11.