JP2011081169A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera capable of improving detection accuracy of a diaphragm opening position of a lens diaphragm. <P>SOLUTION: A cam follower 402f at the end of an arm 402d of a diaphragm lever 402 presses a cam 441a to turn a diaphragm PI blade lever 441 so that movement of the diaphragm lever 402 in release is extended to be transmitted to a diaphragm PI blade 442. The start of movement of the diaphragm lever 402 in the release is detected based on change in an output of a diaphragm PI 443 due to the rotation of the diaphragm PI blade 442. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a camera including an aperture control device that drives an aperture of a lens.

  As a diaphragm control device used for single-lens reflex cameras, the lever on the camera side (aperture lever) that drives the diaphragm provided on the interchangeable lens (photographing lens) is driven by a stepping motor, and the drive amount of the diaphragm lever is stepped It is known that a desired aperture value is obtained by controlling the number of drive pulses of a motor. In this diaphragm control device, the rotation position (hereinafter referred to as the initial position) of the diaphragm lever in the fully open state may differ depending on the photographing lens attached to the camera, and when the photographing lens is removed, In order to prevent breakage when the aperture lever exposed to an external force is subjected to external force, it is necessary to be able to freely rotate when the external force is applied to a portion exposed to the outside when the photographing lens is removed. Therefore, the aperture lever is configured to be driven by an aperture drive lever that is rotated by a stepping motor via the aperture first gear and the aperture second gear, and is exposed to the outside when the photographing lens is removed. When an external force is applied to the portion, it can be freely rotated independently of the aperture driving lever.

  In the aperture device configured as described above, in order to set the aperture of the photographing lens to a desired value, the aperture lever on the lens side must be moved downward by a predetermined amount corresponding to the aperture value to be set. That is, it is necessary to rotate the aperture lever (on the camera side) according to the aperture value to be set. For this purpose, the aperture drive lever needs to rotate the aperture lever by a predetermined rotation amount. However, as described above, the initial position of the aperture lever may differ depending on the photographic lens attached to the camera. Therefore, the aperture is rotated by the rotation amount θa from when the aperture drive lever starts to rotate until the aperture lever starts to rotate. The drive lever has a play amount of rotation. Therefore, in order to rotate the aperture lever by a predetermined rotation amount (for example, θf), the aperture drive lever has to be rotated by the above-described rotation amount θa. However, since the initial position of the aperture lever may differ depending on the photographing lens as described above, the rotation amount θa does not become a constant value, and the total number of drive pulses that the stepping motor driver outputs to the stepping motor during the aperture operation is as follows. I do not understand.

  Therefore, in the above-described diaphragm device, the diaphragm photo-interrupter (diaphragm PI) detects the start of rotation of the diaphragm photo-interrupter blade (diaphragm PI blade), so that the diaphragm drive lever rotates by the rotation amount θa described above. The timing for starting the rotation of the lever is detected. Then, the aperture of the photographing lens is set to a desired value by controlling the stepping motor so that the aperture driving lever is further rotated by the aperture rotation amount θf, based on the detection of the start of rotation of the aperture lever. (Refer patent document 1).

JP 2009-42296 A

  However, in the diaphragm control device described in the above-mentioned patent document, in order to improve the detection accuracy of the rotation start of the diaphragm lever, it is necessary to improve the resolution by increasing the speed of the diaphragm PI blade. However, if the speed increasing ratio of the aperture PI blade is increased in order to obtain high resolution, it becomes impossible to follow the moving speed of the aperture lever due to the influence of the moment of inertia of the aperture PI blade, and the detection accuracy of the aperture opening position of the in-lens aperture lever On the contrary, there is a risk that it will fall.

(1) The camera according to the first aspect of the invention includes a first aperture driving member that drives the lens aperture in the aperture direction so that the aperture value of the lens aperture is set to an arbitrary aperture value from the open aperture value, and the first aperture stop. A diaphragm second drive member that drives the first diaphragm drive member, a motor that drives the second diaphragm drive member, and a lens diaphragm aperture value that is an open aperture value so that the drive member drives the lens diaphragm in the direction of narrowing. Detection means for detecting the start of movement of the aperture first drive member when the aperture value is set to an arbitrary aperture value, a transmission mechanism for transmitting the movement of the aperture first drive member to the detection means, and a transmission mechanism for biasing the transmission mechanism And the transmission mechanism is configured to increase the amount of movement of the first diaphragm driving member transmitted to the detection means in the vicinity of the position where the first diaphragm driving member starts to move, compared to other positions. Including cam and cam follower The transmission mechanism urging means urges the transmission mechanism so that the cam and the cam driven member are not separated from each other, and the transmission mechanism is located near the position where the first diaphragm driving member starts to move. The cam is pressed against the cam driven member by the movement, or the cam driven member is pressed against the cam by the movement of the first aperture driving member.
(2) The invention according to claim 2 is the camera according to claim 1, wherein the diaphragm second drive member includes a drive member that urges the diaphragm second drive member in the same direction as the direction in which the diaphragm first drive member is driven. The transmission mechanism further includes an urging means, and the transmission mechanism applies an urging force by the driving member urging means when the aperture first driving member is positioned at a position where the aperture value of the lens aperture becomes a value close to the open aperture value. The urging force by the transmission mechanism urging means is transmitted to the first diaphragm driving member and the second diaphragm driving member so as to decrease.
(3) According to a third aspect of the present invention, in the camera according to the second aspect, the driving member urging means causes the second diaphragm driving as the second diaphragm driving member rotates in a direction to drive the first diaphragm driving member. The urging force for urging the member decreases, and the transmission mechanism transmits the diaphragm second drive member to the diaphragm first drive member and the diaphragm second drive member as the diaphragm second drive member rotates in the direction of driving the diaphragm first drive member. The urging force by the transmission mechanism urging means is reduced.
(4) According to a fourth aspect of the present invention, in the camera according to the third aspect of the present invention, when the transmission mechanism is further rotated in a direction in which the second diaphragm driving member drives the first diaphragm driving member, the driving member is urged. The urging force by the transmission mechanism urging means is transmitted to the first diaphragm driving member and the second diaphragm driving member so as to increase the urging force by the means.
(5) The invention of claim 5 is the camera according to any one of claims 1 to 4, wherein the detecting means has a light emitting part and a light receiving part facing each other, and the light from the light emitting part is received by the light receiving part. It is a photo interrupter configured to detect, and a transmission mechanism includes a slit disk provided with a slit portion that transmits light emitted from the light emitting portion toward the light receiving portion, and a non-slit portion that blocks light, and a slit A lever for rotating the disk, the cam and the cam driven member transmit the movement of the first diaphragm driving member to the lever, and the lever is moved by the movement of the first diaphragm driving member transmitted from the cam and the cam driven member. The slit disk is rotated, and the photo interrupter detects whether or not the detection state of the light from the light emitting unit in the light receiving unit is changed by the rotation of the slit disk due to the movement of the aperture first driving member. Thus, the start of movement of the aperture first drive member is detected.

  According to the present invention, it is possible to improve the detection accuracy of the aperture opening position of the lens aperture.

1 is a perspective view showing a single-lens reflex type camera body 1 and an imaging lens 2 attached to the camera body 1, which are electronic cameras to which an aperture control device according to the present invention is applied. It is the exploded view which mainly showed the main components regarding the drive of the lens side aperture lever 3 among the aperture mechanisms 400 integrated in the camera body 1, and has shown the state (aperture open state) before the release operation | movement start. FIG. 6 is a view of a part of the aperture mechanism 400 when viewed from the left side of the camera body 1 toward the right side. FIG. 6 is a view of a part of the aperture mechanism 400 when viewed from the left side of the camera body 1 toward the right side. FIG. 6 is a view of a part of the aperture mechanism 400 when viewed from the left side of the camera body 1 toward the right side. It is a figure which shows the vicinity of the aperture PI blade | wing 442. FIG. It is a graph which shows the relationship between the rotation angle (rotation angle) of the aperture lever 402, and the number of output pulses output from aperture PI443. The horizontal axis represents the rotation angle of the aperture lever 402, and the vertical axis represents the torque that the aperture lever 402 tries to rotate in the aperture direction.

  An embodiment of a camera according to the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a single-lens reflex type camera body 1 and an imaging lens 2 attached to the camera body 1, which are electronic cameras to which an aperture control device according to the present invention is applied. The camera body 1 is provided with a release button 4, a CCD 5 that is an image sensor, a control circuit 101 that controls each part of the camera body 1, a stepping motor driver 102, and an aperture mechanism 400. Reference numeral 301 denotes a photographing optical path for guiding a subject image from the photographing lens 2 to the CCD 5, and reference numeral 321 denotes a main mirror. In the electronic camera of the present embodiment, the exposure time is controlled by a so-called electronic shutter that controls the charge accumulation time of the CCD 5 by a control signal from the control circuit 101.

  When the photographic lens 2 is attached to the camera body 1, the lens side diaphragm lever 3 and the contact portion 402b of the camera side diaphragm lever 402 come into contact with each other. The lens side diaphragm lever 3 is driven by a camera side diaphragm lever (hereinafter simply referred to as a diaphragm lever) 402 and controlled to a predetermined diaphragm value. In the present embodiment, the front side of the camera body 1 to which the photographing lens 2 is attached is defined as the front, and the back side of the camera body 1 provided with the CCD 5 is defined as the rear. Further, the vertical and horizontal directions of the camera body 1 are defined as shown in each drawing.

--- Aperture mechanism 400 ---
FIG. 2 is an exploded view mainly showing main components related to driving of the lens side diaphragm lever 3 in the diaphragm mechanism 400 incorporated in the camera body 1, and shows a state before starting the release operation (aperture open state). Show. 3 to 5 are views when a part of the diaphragm mechanism 400 is viewed from the left side to the right side of the camera body 1, and for the sake of explanation, the outer shape including a hidden part of some members is indicated by a thick line. I'm drawing. FIG. 3 shows a fully open state, FIG. 4 shows a state in the middle of narrowing, and FIG. 5 shows a narrowed state. Note that the front-rear direction and the up-down and left-right directions in these drawings are defined so as to coincide with the front-rear direction and the up-down and left-right directions of the camera body 1, assuming that the aperture mechanism 400 is incorporated in the camera body 1.

  In the following description of each component of the diaphragm mechanism 400, the posture and position, the extending direction of the arm, the relationship with other members, etc. are mainly the diaphragm open state shown in FIGS. This will be described on the assumption. As shown in FIGS. 2 and 3, the diaphragm mechanism 400 includes a substrate 401, a diaphragm lever 402, a diaphragm drive lever 403, a diaphragm return lever 404, a diaphragm lever locking claw 405, and a stepping motor 411. Yes. The diaphragm mechanism 400 includes a diaphragm first gear 421, a diaphragm second gear 422, a diaphragm return locking lever 431, and a diaphragm magnet 434. The aperture mechanism 400 is an aperture control device that controls the aperture of the photographic lens 2.

  The substrate 401 is a plate-like member to which each component of the diaphragm mechanism 400 is attached. The diaphragm lever 402 is a lever that is pivotally supported around a boss 401 a provided on the substrate 401, and is a diaphragm driving member that drives the diaphragm of the photographing lens 2.

  The aperture lever 402 includes arms 402a, 402d, and 402e, an abutting portion 402b, and a cam follower 402f. The diaphragm lever 402 has one end of a diaphragm return spring 472 engaged with the arm 402e. The aperture lever 402 is connected to an aperture return lever 404 (described later) via an aperture return spring 472. When viewed from the left side of the camera body 1 by the aperture return spring 472, the aperture lever 402 is hereinafter referred to simply as a counterclockwise direction. ). The above-described contact portion 402b is provided at the tip of the arm 402a that extends forward, and contacts the lens-side diaphragm lever 3 of the photographic lens 2 attached to the camera body 1. A pin 402c extending toward the left side is planted on the left side surface of the arm 402a. A cam follower 402f is provided at the tip of an arm 402d that extends rearward and obliquely upward. The cam follower 402f is a cam follower that abuts on a cam 441a of a diaphragm PI blade lever 441, which will be described later, and follows the movement of the cam 441a.

  The aperture driving lever 403 is a lever that drives the aperture lever 402 and is pivotally supported around a boss 401 a provided on the substrate 401. The aperture drive lever 403 includes an arm 403a and a sector gear portion 403c. The arm 403a extends forward, and presses a pin 402c provided on the arm 402a of the aperture lever 402 downward as described later. The sector gear portion 403c is a sector gear portion provided along an arc centered on the boss 401a, and meshes with a diaphragm second gear 422 to be described later. A pin 403b is implanted in the arm 403a. The pin 403b pivotally supports an aperture lever locking claw 405 described later. A pin 403d is planted in the vicinity of the sector gear portion 403c. The aperture driving lever 403 is rotated by a stepping motor 411 described later.

  The aperture return lever 404 is a lever that applies an urging force of the aperture spring 471 to the aperture drive lever 403, and is pivotally supported around a boss 401 a provided on the substrate 401. The aperture return lever 404 includes an arm 404a extending obliquely downward and forward and an arm 404c extending downward. A bent portion 404b bent toward the left is provided at the tip of the arm 404a.

  The arm 404c is provided with a throttle return spring locking portion 404d, a contact portion 404e, and a narrowing spring locking portion 404f. The other end of the aperture return spring 472 is engaged with the aperture return spring locking portion 404d. The contact portion 404e is in contact with a diaphragm return locking lever 431 described later. One end of a narrowing spring 471 is locked to the narrowing spring locking portion 404f. The other end of the narrowing spring 471 is locked to the substrate 401. Accordingly, the aperture return lever 404 is urged clockwise by the aperture spring 471 when viewed from the left side of the camera body 1 (hereinafter simply referred to as clockwise). However, since the abutting portion 404e is in contact with the aperture return locking lever 431, the aperture return lever 404 resists the urging force of the aperture spring 471 as shown in FIGS. (Dynamic phase).

  As described above, the aperture lever locking claw 405 is a member that is pivotally supported by the pin 403b on the aperture drive lever 403, and includes an arm 405a and a locking portion 405b. As will be described later, the aperture lever locking claw 405 locks the pin 402c provided on the arm 402a of the aperture lever 402 with the locking portion 405b when the aperture is narrowed down. That is, the aperture lever locking claw 405 locks the aperture lever 402 and the aperture drive lever 403 to each other when the aperture is narrowed down. The aperture lever locking claw 405 is biased counterclockwise by a spring 485 (see FIG. 4).

  The stepping motor 411 is, for example, a claw pole PM type stepping motor, and the rotation speed, rotation amount, stop phase (stop position), etc. of the output shaft 411a (see FIG. 3) are controlled by the stepping motor driver 102. The stepping motor 411 rotates the aperture first gear 421 via a reduction gear 493 (see FIG. 3). That is, the rotation of the output shaft 411 a of the stepping motor 411 is decelerated by the reduction gear 493 and transmitted to the first aperture gear 421. The aperture first gear 421 is a worm that is rotated by a stepping motor 411. The stepping motor driver 102 is a driver that controls the driving of the stepping motor 411.

  The aperture second gear 422 is a gear for reducing the rotation of the aperture first gear 421 and transmitting it to the aperture drive lever 403. The aperture second gear 422 includes fan-shaped gear portions 422a and 422b. The sector gear portion 422a is a gear that meshes with the first aperture gear 421 and corresponds to a part of the worm wheel. In other words, the first worm gear 421 and the sector gear 422a of the second diaphragm gear 422 constitute a worm gear. The sector gear portion 422 b meshes with the sector gear portion 403 c of the aperture driving lever 403.

  The aperture return locking lever 431 is a lever that locks the aperture return lever 404 as described above, and absorbs the contact lever 432 that contacts the contact portion 404e of the aperture return lever 404 and the overcharge at the time of reset. For this reason, it is composed of two levers, an overcharge absorption lever 433. The contact lever 432 includes a contact portion 432a that contacts the contact portion 404e of the aperture return lever 404, and a movable iron core engaging portion 432b that engages with a movable iron core of a diaphragm magnet 434 described later.

  Both the contact lever 432 and the overcharge absorption lever 433 are pivotally supported on a shaft 401 d provided on the substrate 401. In the aperture return locking lever 431, the contact lever 432 is urged counterclockwise around the axis 401d by the spring 435, and the overcharge absorption lever 433 is urged clockwise around the axis 401d in the figure. . That is, the aperture return locking lever 431 is integrated with the contact lever 432 and the overcharge absorption lever 433 that are urged toward each other by the spring 435 and contact each other. The aperture return locking lever 431 is urged clockwise by a spring 436 in the drawing.

  The aperture magnet 434 is a known combination magnet that holds the inserted movable iron core 434a (see FIG. 4) by attracting it with a permanent magnet and releases the movable iron core 434a so that the movable iron core 434a can be detached when energized. . The end portion of the movable iron core 434 a exposed from the aperture magnet 434 is engaged with the movable iron core engaging portion 432 b of the contact lever 432.

  In addition to the components described above, the diaphragm mechanism 400 includes a mirror up lever 406 for mirroring up the main mirror 321, a mirror up magnet 461, and a charge lever 407 for performing reset (charging operation) after release. A charge link plate 408 and a charge link lever 409. As shown in FIG. 3, the aperture mechanism 400 includes an aperture PI blade lever 441, an aperture PI blade 442, and an aperture PI 443.

  The mirror up lever 406 is a lever for rotating the main mirror 321, is pivotally supported around the boss 401 a of the substrate 401, and is urged clockwise by a mirror up spring 473 (see FIG. 2). The mirror up lever 406 rotates clockwise by the urging force of the mirror up spring 473 when the main mirror 321 is mirrored up, and the arm 406a abuts on a shaft (not shown) that drives the main mirror 321 and Push up. The mirror-up magnet 461 is a well-known combination magnet that holds the inserted movable iron core 461a by attracting and holding it with a permanent magnet and releases the movable iron core 461a so as to be detached when energized to the exciting coil.

  The charge lever 407 is a lever that is rotated at the time of resetting, and is pivotally supported so as to be rotatable around a boss 401 a of the substrate 401. The charge lever 407 has arms 407a and 407b. The arm 407a is a part that abuts against the bent portion 404b of the aperture return lever 404 and presses the bent portion 404b counterclockwise at the time of reset. The arm 407b is pivotally supported with respect to the upper end of the charge link plate 408 described below.

  The charge link plate 408 is a plate-like member for transmitting a charging force by a sequence motor (not shown) to the charge lever 407 and the like. As described above, the charge link plate 408 is pivotally supported at the upper end so as to be rotatable with respect to the arm 407b of the charge lever 407, and the lower end is pivotally supported at one end of the charge link lever 409 described below. ing. A charge roller 482 is attached to the lower end of the charge link plate 408. The charge roller 482 is a roller to which a charge force from a sequence motor (not shown) is input, and is pressed downward by the charge force of the sequence motor at the time of reset. A boss 408 a is provided on the left side surface of the charge link plate 408. The boss 408a contacts the overcharge absorbing lever 433 of the aperture return locking lever 431 at the time of reset, and rotates the aperture return locking lever 431 counterclockwise.

  The charge link lever 409 is a lever that restricts the movement of the lower end of the charge link plate 408, one end of which is pivotally supported by the lower end of the charge link plate 408 and the other end of a shaft 401 e provided on the substrate 401. It is pivotally supported at the center so as to be rotatable. The board 401, the charge lever 407, the charge link plate 408, and the charge link lever 409 constitute a four-link mechanism. The charge link lever 409 is urged clockwise by a spring 484.

  As shown in FIG. 3, the aperture PI blade lever 441 is a lever that contacts the aperture lever 402 and rotates according to the rotation position of the aperture lever 402. The aperture PI blade lever 441 is pivotally supported by a shaft 401 f provided on the substrate 401. The aperture PI blade lever 441 is provided with a cam 441a with which a cam follower 402f of the aperture lever 402 abuts and a gear portion 441b that meshes with a gear portion of an aperture PI blade 442 described later. The cam profile of the cam 441a will be described in detail later.

  The aperture PI blade 442 is a member that is rotated by the aperture PI blade lever 441, and includes a slit blade portion 442a and a gear portion 442b as shown in FIG. FIG. 6 is a view showing the vicinity of the aperture PI blade 442, and a portion hidden by each member is indicated by a thin line. The slit blade part 442a is a disk-shaped member provided with a plurality of small holes (slits) radially. The gear portion 442b is a gear provided on the right side surface of the slit blade portion 442a (the back side in FIG. 6), and meshes with the gear portion 441b of the aperture PI blade lever 441 as described above. Therefore, the aperture PI blade 442 is rotated according to the rotation of the aperture PI blade lever 441. The aperture PI blade 442 is biased counterclockwise by a spring 483 (see FIG. 3). Thereby, the aperture PI blade lever 441 in which the gear portion 441b is engaged with the gear portion 442b is urged clockwise in the figure. Note that the spring 483 moves each member in one direction in order to suppress a decrease in rotation position detection accuracy due to rattling of each member related to rotation position detection of the aperture lever 402, such as backlash of the gear portions 441b and 442b. It also plays a role in energizing.

  The aperture PI 443 is an optical sensor (photo interrupter) having a light emitting portion and a light receiving portion facing each other. When the slit of the slit blade portion 442a moves in the vicinity of the detection portion by the rotation of the aperture PI blade 442, the position of the slit In response to this, an on / off signal (pulse signal) is output. A pulse signal of the aperture PI 443 is output to the control circuit 101. The control circuit 101 determines the presence / absence of rotation of the aperture PI blade 442 based on the pulse signal output from the aperture PI 443. That is, the control circuit 101 determines the presence or absence of rotation of the aperture lever 402 that has been rotated to the rotation position where the lens aperture is close to the open position based on the pulse signal output from the aperture PI 443. .

  In addition to the components described above, the aperture mechanism 400 includes an initial position PI blade rotation lever, an initial position PI blade, and an initial position PI. Although detailed description is omitted, the initial position PI blade rotation lever, the initial position PI blade, and the initial position PI are the stop position of the diaphragm drive lever 403 when the diaphragm mechanism 400 is reset (the stop before the release of the diaphragm drive lever 403). Used to determine the position).

---- Description of operation ---
The diaphragm mechanism 400 configured as described above is described in a patent application published by the present applicant (Japanese Patent Laid-Open No. 2009-42296), except for the detection of the start of movement of the diaphragm lever 402 described below. This is similar to the operation of the diaphragm mechanism 400 and is well known. Therefore, in the following description, the difference from the operation of the aperture mechanism 400 described in the above-mentioned published patent gazette and the part related to this difference will be mainly explained, and the aperture mechanism described in the above-mentioned published patent gazette. A part of the description of the operation similar to the operation 400 is omitted.

---- Opened aperture state ---
In the aperture open state, as shown in FIGS. 2 and 3, the aperture lever 402 is rotated counterclockwise and stopped. The diaphragm lever 402 is given a counterclockwise biasing force by a diaphragm return spring 472. When the photographic lens 2 is attached to the camera body 1, the contact portion 402 b of the aperture lever 402 contacts the lens side aperture lever 3, so that the aperture lever 402 is attached to the camera body 1 with the photographic lens 2. It stops in a state of being slightly rotated clockwise compared to the case where it is not. The stop position of the aperture lever 402 at this time is referred to as “pre-release stop position of the aperture lever 402 when the lens is mounted”. The stop position of the aperture lever 402 when the photographic lens 2 is not attached to the camera body 1 is referred to as “pre-release stop position of the aperture lever 402 when the lens is not attached”.

  The aperture drive lever 403 is stopped in a state where the arm 403a is separated from the pin 402c on the aperture lever 402. The stop position of the aperture drive lever 403 at this time is referred to as “pre-release stop position of the aperture drive lever 403”. As described above, the aperture driving lever 403 is rotated by the stepping motor 411, and the aperture first gear 421 and the aperture second gear 422 are provided between the stepping motor 411 and the aperture driving lever 403. A worm gear constituted by is interposed. Therefore, if the stepping motor 411 is stopped even if an external force is applied to the aperture driving lever 403, the aperture driving lever 403 does not rotate due to the automatic tightening (self-locking) of the worm gear. The “stop position before release of the aperture driving lever 403” is defined by the position where the output shaft 411a of the stepping motor 411 stops.

  The diaphragm lever locking claw 405 stops in a state where the arm 405a abuts against the folded portion 401b of the substrate 401 and is rotated clockwise against the biasing force of the spring 485. Accordingly, the locking portion 405b is separated from the pin 402c on the aperture lever 402 and releases the pin 402c.

  The aperture return lever 404 rotates counterclockwise against the biasing force of the aperture spring 471 by the contact portion 404e coming into contact with the contact portion 432a of the contact lever 432 (diaphragm return locking lever 431). It is locked in the state that was done. At this time, the lower end of the arm 404 a of the aperture return lever 404 is slightly separated from the pin 403 d provided in the vicinity of the sector gear portion 403 c of the aperture drive lever 403. The aperture return locking lever 431 is locked by the movable iron core 434a of the aperture magnet 434 while being rotated counterclockwise against the biasing force of the spring 436.

  Since the arm 402d of the aperture lever 402 is moved rearward, the aperture PI blade lever 441 is rotated clockwise by the biasing force of the spring 483 received through the aperture PI blade 442 and stopped.

---- During release ----
When the release button 4 is pressed, a release signal is output to the control circuit 101 from a release switch (not shown). When the release signal is input, the control circuit 101 excites the mirror up magnet 461 for a predetermined time necessary for releasing the movable iron core 461a. Thereby, the movable iron core 461a is released. Although a detailed description is omitted, when the movable iron core 461a is released, the lock of the mirror up lever 406 is released, and the mirror up lever 406 rotates in the clockwise direction in the figure by the urging force of the mirror up spring 473. . As a result, the arm 406a comes into contact with a shaft (not shown) that drives the main mirror 321, and pushes the shaft upward to mirror up the main mirror 321.

  Further, when the release signal is input, the control circuit 101 excites the aperture magnet 434 for a predetermined time necessary for releasing the movable iron core 434a. As a result, the movable iron core 434a is released, and the squeezing return locking lever 431 is rotated clockwise by the urging force of the spring 436 to release the locking of the squeezing return lever 404. The aperture return lever 404 is rotated in the clockwise direction by the urging force of the aperture spring 471 and presses the pin 403d provided in the vicinity of the sector gear 403c of the aperture drive lever 403 in the clockwise direction at the lower end of the arm 404a. To do. As a result, the diaphragm driving lever 403 is given a biasing force in the clockwise direction in the drawing, that is, in the narrowing-down direction.

  When the release signal is input, the control circuit 101 outputs a control signal to the stepping motor driver 102 so as to start the rotation of the stepping motor 411 in the narrowing direction simultaneously with the start of excitation of the aperture magnet 434. When receiving the control signal from the control circuit 101, the stepping motor driver 102 starts driving the stepping motor 411 in the narrowing-down direction. When the stepping motor 411 is driven in the aperture direction, the aperture drive lever 403 is rotated in the clockwise direction in the drawing via the aperture first gear 421 and the aperture second gear 422.

  When the aperture driving lever 403 rotates in the clockwise direction in the drawing, the arm 403a comes into contact with the pin 402c on the aperture lever 402 and presses the pin 402c downward. Thereby, the aperture lever 402 is rotated in the clockwise direction in the drawing, and the aperture operation is started. That is, the lens side diaphragm lever 3 narrows the diaphragm of the taking lens 2 from the open state by the rotation of the diaphragm lever 402 in the clockwise direction in the drawing.

  The diaphragm drive lever 403 rotates in the clockwise direction in the drawing, so that the arm 405 a of the diaphragm lever locking claw 405 is separated from the folded portion 401 b of the substrate 401. As a result, the aperture lever locking claw 405 is rotated counterclockwise in the figure by the urging force of the spring 485, and the locking portion 405b abuts on the pin 402c on the aperture lever 402 and holds and locks the pin 402c. . Therefore, the aperture lever 402 and the aperture drive lever 403 are locked to each other by the aperture lever locking claw 405 and rotate integrally. At the time of narrowing, the diaphragm driving lever 403 and the diaphragm lever 402 are driven by the driving force of the stepping motor 411 and the biasing force of the narrowing spring 471.

  The stepping motor driver 102 controls the rotation amount of the output shaft 411a of the stepping motor 411 based on the control signal from the control circuit 101 so that a desired aperture value can be obtained. Thereby, the stepping motor 411 stops after the output shaft 411a rotates by a predetermined rotation amount. When the stepping motor 411 is stopped, the diaphragm drive lever 403 and the diaphragm lever 402 integrated by the diaphragm lever locking claw 405 are also stopped by the above-described self-locking of the worm gear. As a result, the lens side diaphragm lever 3 is stopped, and the diaphragm of the photographing lens 2 is set to a desired value.

  As described above, after the aperture of the photographing lens 2 is set to a desired value, a shutter (not shown) is operated by a well-known device to perform a photographing operation. A reset operation is performed. Description of the reset operation is omitted.

--- About drive control of stepping motor 411 at the time of narrowing down ---
In order to set the aperture of the taking lens 2 to a desired value, the lens-side aperture lever 3 must be moved downward by a predetermined amount corresponding to the aperture value to be set. That is, it is necessary to rotate the aperture lever 402 according to the aperture value to be set. For this purpose, the aperture drive lever 403 needs to rotate the aperture lever 402 by a predetermined rotation amount.

  In the state before the release, as described above, the aperture driving lever 403 is stopped in a state where the arm 403a is separated from the pin 402c on the aperture lever 402. Therefore, in order to rotate the aperture lever 402 by a predetermined rotation amount (for example, θf), the aperture drive lever 403 rotates an extra rotation amount (for example, θa) required until the arm 403a is brought into contact with the pin 402c. Must move. That is, before starting to stop the aperture of the taking lens 2, the aperture driving lever 403 needs to rotate clockwise in the figure by the rotation amount θa.

  Therefore, in order to set the aperture of the taking lens 2 to a desired value, the aperture drive lever 403 is rotated from the “stop position before the release of the aperture drive lever 403” to the total rotation of the rotation amount θf and the rotation amount θa. It must be rotated by the amount of movement θf + θa. In the following description, the rotation amount θf is referred to as a narrowing rotation amount, and the rotation amount θa is referred to as a rotation amount before starting the narrowing.

  The desired aperture value and the amount of downward movement of the lens side aperture lever 3 necessary for obtaining the desired aperture value are calculated based on an output signal from a photometric sensor (not shown), thereby narrowing down the aperture. The rotation amount θf can be calculated. The rotation amount θa before starting the aperture is determined by “the stop position before the release of the aperture lever 402 when the lens is mounted” and “the stop position before the release of the aperture drive lever 403”. However, since “the stop position before the release of the aperture lever 402 when the lens is mounted” may differ depending on the photographic lens 2 to be mounted, the rotation amount θa before starting the aperture does not become a constant value.

  As described above, the aperture driving lever 403 is configured to be rotated by the stepping motor 411 via the aperture first gear 421 and the aperture second gear 422. Therefore, the rotation amount of the aperture driving lever 403 can be controlled by the driving amount of the stepping motor 411, that is, the number of driving pulses output from the stepping motor driver 102 to the stepping motor 411. However, since the rotation amount θa before the start of narrowing does not become a constant value, the total number of drive pulses output by the stepping motor driver 102 to the stepping motor 411 during the narrowing operation is unknown.

  Therefore, in the aperture mechanism 400 of the present embodiment, the aperture PI 443 detects the start of rotation of the aperture PI blade 442, so that the aperture drive lever 403 rotates by the rotation amount θa before the aperture start, and the aperture lever 402 rotates. The timing to start is detected. Then, the stepping motor 411 is controlled so as to further rotate the aperture driving lever 403 by the aperture rotation amount θf with the detection start of the rotation of the aperture lever 402 as a base point. The aperture lever 402 is rotated by the aperture amount θf from the “pre-release stop position”. Thus, by controlling the rotation amount of the aperture driving lever 403, that is, the driving amount of the stepping motor 411, the aperture of the photographing lens 2 is set to a desired value.

  Specifically, when a release signal is input, the control circuit 101 calculates a target aperture value (set aperture value) of the photographing lens 2 based on an output signal from a photometric sensor (not shown). The control circuit 101 calculates the aperture rotation amount θf of the aperture lever 402 (or the number of drive pulses corresponding to the aperture rotation amount θf) for obtaining the set aperture value. Then, the control circuit 101 outputs information on the calculated narrowing rotation amount θf (or the number of drive pulses corresponding to the narrowing rotation amount θf) to the stepping motor driver 102. In the following description, for convenience, it is assumed that information on the number of drive pulses corresponding to the narrowing rotation amount θf is output from the control circuit 101. In addition to the information on the number of drive pulses corresponding to the aperture rotation amount θf, as described above, when the release signal is input, the control circuit 101 rotates the stepping motor 411 simultaneously with the start of excitation of the aperture magnet 434. A control signal is output to the stepping motor driver 102 so as to start the movement.

  When receiving the control signal from the control circuit 101, the stepping motor driver 102 starts driving the stepping motor 411.

  When driving of the stepping motor 411 is started, the aperture driving lever 403 is rotated. When the aperture driving lever 403 is rotated by the rotation amount θa before the start of narrowing, the separated arm 403a and the pin 402c come into contact with each other, and the rotation of the aperture lever 402 is started. When rotation of the aperture lever 402 is started, the cam follower 402f at the tip of the arm 402d moves forward. As a result, the cam 441a that is in contact with the cam follower 402f, that is, the aperture PI blade lever 441 rotates counterclockwise in the figure, and the aperture PI blade 442 rotates in the clockwise direction against the biasing force of the spring 483. As described above, the start of rotation of the aperture PI blade 442 is detected by the aperture PI 443.

  When detecting that the state of the output signal of the aperture PI 443 has changed, the control circuit 101 outputs a signal (aperture lever rotation start signal) indicating that the aperture lever 402 has started rotating to the stepping motor driver 102. .

  The stepping motor driver 102 receives a drive pulse from the control circuit 101 to the stepping motor 411 by the number of drive pulses based on the information of the number of drive pulses corresponding to the aperture rotation amount θf from the time when the stop lever rotation start signal is received from the control circuit 101. After the output, the stepping motor 411 is stopped.

--- Advantages of the present invention and cam profile of the cam 441a ---
In the diaphragm control device described in the above-mentioned published patent publication (Japanese Patent Laid-Open No. 2009-42296), in order to improve the detection accuracy of the rotation start of the diaphragm lever, the resolution is improved by increasing the speed of the diaphragm PI blade. It is necessary to let However, if the speed increasing ratio of the aperture PI blade is increased in order to obtain high resolution, it becomes impossible to follow the moving speed of the aperture lever due to the influence of the moment of inertia of the aperture PI blade, and the detection accuracy of the aperture opening position of the in-lens aperture lever On the contrary, there is a risk that it will fall.

  In order to make the aperture PI blade follow the moving speed of the aperture lever, it is assumed that the aperture PI blade (corresponding to the aperture PI blade 442 of the present embodiment) and the aperture lever (corresponding to the aperture lever 402 of the present embodiment) are geared. It is conceivable to connect them via However, in this case, as the aperture lever 402 (aperture drive lever 403) is driven in the aperture direction (clockwise in the drawing), the biasing force of the aperture lever 402 in the aperture direction by the aperture spring 471 is weakened, and the spring 483 The biasing force in the direction opposite to the narrowing direction of the diaphragm lever 402 is increased. The squeezing spring 471 is weakened when the squeezing lever 402 (diaphragm driving lever 403) is driven in the squeezing direction (clockwise in the figure), but the spring 483 is squeezed by the diaphragm lever 402 (diaphragm driving lever 403). When driven in the direction (clockwise in the figure), the urging force increases. This is because the aperture PI blade 442 is rotated clockwise to wind up the spring 483.

  As a result, the urging force to drive the aperture lever 402 (aperture drive lever 403) in the aperture direction (clockwise in the figure) is further weakened, and the drive force of the aperture lever 402 (aperture drive lever 403) may be insufficient. is there. Further, the occupied space of the gear becomes large, and the diaphragm mechanism 400 becomes large. Further, it is only necessary to detect the start of movement of the aperture lever 402, but if the aperture is connected with a gear as described above, the aperture PI blade 442 rotates at a constant acceleration over the entire rotation range of the aperture lever 402. Therefore, the aperture PI blade 442 rotates more than necessary, and the spring 483 is wound up more than necessary.

  In order to prevent such a problem, when the biasing force of the narrowing spring 471 is increased (so as to overcome the biasing force of the wound spring 483), the throttle lever 402 (throttle drive lever 403) is moved in the narrowing direction (illustrated). Since the urging force that drives in the clockwise direction is too strong near the aperture opening position, even if an attempt is made to stop the aperture lever 402 (diaphragm drive lever 403) near the aperture opening position, the stepping motor 411 stops without stopping. There is a risk that.

  Therefore, in the present embodiment, by devising the profile of the cam 441a, the amount of rotation of the aperture PI blade 442 relative to the amount of rotation of the aperture lever 402 is increased in the vicinity of the aperture opening position as shown in FIG. The speed increasing ratio is increased), that is, the amount of rotation of the aperture lever 402 is increased to improve the detection accuracy of the movement start of the aperture lever 402. Then, at the position where the aperture is further narrowed to some extent than the vicinity of the aperture opening position, the amount of rotation of the aperture PI blade 442 relative to the amount of rotation of the aperture lever 402 is reduced (the speed increase ratio is reduced), and the unnecessary aperture PI blade 442 is used. The profile of the cam 441a is set so that the spring 483 is not wound more than necessary.

  FIG. 7 is a graph showing the relationship between the rotation angle (rotation angle) of the aperture lever 402 and the number of output pulses output from the aperture PI 443. The horizontal axis in FIG. 7 indicates the rotation angle of the aperture lever 402, and the rotation position when the aperture lever 402 is most rotated in the aperture opening direction is 0 degree. The broken line graph in FIG. 7 indicates the number of output pulses of the aperture PI 443 per rotation angle of the aperture lever 402. The solid line graph in FIG. 7 shows the cumulative number of output pulses output from the aperture PI 443 (hereinafter referred to as the cumulative pulse number) with reference to the time when the rotation angle of the aperture lever 402 is 0 degree.

  As shown by the broken line graph in FIG. 7, when the rotation angle of the aperture lever 402 is near 0 degrees, that is, in the vicinity of the aperture open position, the number of output pulses of the aperture PI 443 per rotation angle of the aperture lever 402 is large. The number of output pulses of the aperture PI 443 per rotation angle of the aperture lever 402 decreases as the rotation in the aperture direction progresses. When the rotation angle of the aperture lever 402 exceeds θr shown in FIG. 7, the number of output pulses of the aperture PI 443 per rotation angle of the aperture lever 402 takes a negative value.

  The reason why the number of output pulses of the aperture PI 443 per rotation angle of the aperture lever 402 takes a negative value is that the rotation direction of the aperture PI blade 442 is reversed when the rotation angle of the aperture lever 402 exceeds θr, as will be described later. This is because the profile of the cam 441a is set. Accordingly, until the rotation angle of the aperture lever 402 exceeds θr, the aperture PI blade 442 rotates in the clockwise direction as the aperture lever 402 rotates in the aperture direction. When the rotation angle of the aperture lever 402 exceeds θr, the aperture PI blade 442 rotates counterclockwise as the aperture lever 402 rotates in the aperture direction. FIG. 4 is a diagram illustrating a state of the diaphragm mechanism 400 when the rotation angle of the diaphragm lever 402 is approximately θr.

  As shown by the solid line graph in FIG. 7, the cumulative number of pulses increases as the rotation of the diaphragm lever 402 in the narrowing direction proceeds until the rotation angle of the diaphragm lever 402 exceeds θr. When the angle exceeds θr, the angle decreases as the rotation of the aperture lever 402 in the aperture direction proceeds. In the solid line graph of FIG. 7, the cumulative pulse number is increased when the aperture PI blade 442 rotates in the clockwise direction shown in the figure, and the cumulative pulse number is decreased when the aperture PI blade 442 rotates in the counterclockwise direction shown in the figure. It is described as follows. Therefore, the solid line graph in FIG. 7 is also a graph showing the rotation angle of the aperture PI blade 442 with the clockwise direction shown in the figure as positive.

  Further, by devising the profile of the cam 441a, the angle at which the force by which the spring 483 tries to rotate the diaphragm lever 402 counterclockwise acts on the arm of the diaphragm lever 402 is changed. As a result, the urging force itself of the aperture PI blade 442 by the spring 483 increases as the squeezing progresses, but the urging force in the counterclockwise direction of the aperture lever 402 by the spring 483 is weakened. In the vicinity of the aperture opening position of the aperture lever 402, the force to rotate the aperture lever 402 clockwise by the aperture spring 471 is the strongest. At this time, the counterclockwise rotation of the aperture lever 402 by the spring 483 is performed. The urging force in the direction is the strongest.

  Further, in the vicinity of the rotation position of the aperture lever 402 at which the aperture of the taking lens 2 is most contracted, that is, at a position exceeding the angle θr in FIG. 7, the spring 483 attempts to rotate the aperture lever 402. The input angle (working angle) of the biasing force of the spring 483 from the cam 441a to the arm 402d via the cam follower 402f is adjusted so that the force acts to rotate the aperture lever 402 clockwise. It is set.

  By doing so, the degree to which the force (the resultant force of the urging force of the squeezing spring 471 and the spring 483) that urges the squeezing lever 402 in the squeezing direction by the progress of the squeezing of the squeezing lever 402 is reduced. Even if the rotation angle changes, fluctuations in the force for urging the aperture lever 402 in the aperture direction are suppressed. Thereby, the stopping accuracy when stopping the aperture lever 402 by stopping the stepping motor 411 is stabilized regardless of the rotation position of the aperture lever 402. Further, since the required torque of the stepping motor 411 can be reduced, the stepping motor 411 can be reduced in size.

  In FIG. 8, the horizontal axis represents the rotation angle of the aperture lever 402, and the vertical axis represents the torque that the aperture lever 402 tends to rotate in the aperture direction (hereinafter referred to as aperture torque), that is, the aperture spring 471 and the spring 483. It is the graph which showed the torque by urging | biasing force. As indicated by the alternate long and short dash line in FIG. 8, the narrowing torque by the narrowing spring 471 decreases as the diaphragm lever 402 rotates in the narrowing direction. As shown by a broken line in FIG. 8, the narrowing torque by the spring 483 takes a negative value until the rotation angle of the diaphragm lever 402 exceeds θr, and a positive value when the rotation angle of the diaphragm lever 402 exceeds θr. Take. Further, the squeezing torque by the spring 483 increases as the squeezing lever 402 rotates in the squeezing direction. In other words, the cam profile of the cam 441a is set so that the narrowing torque by the spring 483 increases as the narrowing lever 402 rotates in the narrowing direction. Therefore, as shown by the solid line in FIG. 8, it is possible to suppress fluctuations in the narrowing torque accompanying the rotation of the diaphragm lever 402 in the narrowing direction.

The camera body 1 including the diaphragm mechanism 400 described above has the following operational effects.
(1) The cam follower 402f at the tip of the arm 402d of the aperture lever 402 presses the cam 441a to rotate the aperture PI blade lever 441, and enlarges the movement of the aperture lever 402 during release and transmits it to the aperture PI blade 442. It was configured as follows. The start of movement of the aperture lever 402 at the time of release is detected based on the output change of the aperture PI 443 accompanying the rotation of the aperture PI blade 442. Therefore, even if the speed increase ratio of the aperture PI blade 442 is increased to improve the detection accuracy at the beginning of the movement of the aperture lever 402, the aperture PI blade 442 moves due to the influence of the moment of inertia of the aperture PI blade 442. It is possible to prevent a problem that it becomes impossible to follow the above. Thereby, the movement of the aperture lever 402 at the time of release, that is, the aperture opening position of the lens side aperture lever 3 can be detected with high accuracy.

(2) In the vicinity of the aperture opening position of the aperture lever 402, the aperture 4402 is moved counterclockwise by the spring 483 so that the force to rotate the aperture lever 402 clockwise by the aperture spring 471 is reduced. The urging force was configured to act. As the diaphragm lever 402 is further narrowed down, the biasing force of the spring 483 in the counterclockwise direction of the diaphragm lever 402 is reduced. The diaphragm lever 402 is configured to be urged clockwise by a spring 483 when the diaphragm lever 402 further narrows down. By doing so, it is possible to suppress fluctuations in the squeezing torque associated with the rotation of the squeezing lever 402 in the squeezing direction. Therefore, the stopping accuracy when stopping the squeezing lever 402 by stopping the stepping motor 411 is low. Stabilizes regardless of the rotation position. Further, since the required torque of the stepping motor 411 can be reduced, the stepping motor 411 can be reduced in size, and the aperture mechanism 400 and the camera body 1 can be reduced in size. Further, since the power consumption of the stepping motor 411 can be suppressed by reducing the size of the stepping motor 411, the number of images that can be shot can be increased without downsizing a power source such as a battery or replacing or charging the battery.

(3) For example, when a sensor (for example, a potentiometer) that outputs an analog signal is used to detect the start of movement of the aperture lever 402 at the time of release, the analog signal output from this sensor is A / D converted, It is necessary to constantly monitor changes (fluctuations) in values. On the other hand, in the present embodiment, the aperture PI 443 and the aperture PI blade 442 are used to detect the start of movement of the aperture lever 402 at the time of release. As a result, it is only necessary to monitor the presence / absence of a change in the High / Low state of the signal output from the aperture PI 443, so that the circuit configuration of the control circuit 101 can be simplified.

---- Modified example ---
(1) In the above description, the cam follower 402f is provided on the arm 402d of the aperture lever 402 and the cam 441a is provided on the aperture PI blade lever 441. However, the present invention is not limited to this. For example, a cam may be provided on the arm 402d of the aperture lever 402, and a cam follower may be provided on the aperture PI blade lever 441.

(2) In the above description, the aperture PI 443 and the aperture PI blade 442 are used to detect the start of movement of the aperture lever 402, but the present invention is not limited to this. Instead of using a photo interrupter and a slit plate as in the present embodiment, other detection devices such as a commercially available rotary encoder may be used.
(3) In the above description, the aperture lever 402 is biased in the clockwise direction in the figure by the spring 483 when the aperture of the aperture lever 402 progresses and exceeds the angle θr. Is not required.

(4) In the above description, one end of the spring 483 is attached to the aperture PI blade 442, and the spring 483 biases the aperture PI blade 442 in the counterclockwise direction in the drawing, so that the cam 441a moves toward the cam follower 402f. Although configured to be pressed, the present invention is not limited to this. For example, one end of the spring 483 is attached to the aperture PI blade lever 441 instead of the aperture PI blade 442, and the spring 483 biases the aperture PI blade lever 441 in the clockwise direction in the drawing, so that the cam 441a is pressed toward the cam follower 402f. You may comprise.

(5) In the above-described embodiment, the camera body 1 has been described. However, the present invention can be realized even with the diaphragm mechanism 400 alone.
(6) The above-described embodiments and modifications may be combined.

  Note that the present invention is not limited to the above-described embodiment, and a first aperture that drives the lens aperture in the aperture direction so that the aperture value of the lens aperture is set to an arbitrary aperture value from the open aperture value. A driving member; a diaphragm second driving member that drives the first diaphragm driving member so that the first diaphragm driving member drives the diaphragm of the lens in a narrowing direction; a motor that drives the second diaphragm driving member; Detecting means for detecting the start of movement of the aperture first drive member when the aperture value of the aperture is changed from the open aperture value to an arbitrary aperture value, a transmission mechanism for transmitting the movement of the aperture first drive member to the detection means, and a transmission mechanism A transmission mechanism urging means for urging the movement of the diaphragm first drive member to be transmitted to the detection means in the vicinity of the position at which the first diaphragm drive member starts moving, rather than at other positions. Cams configured to expand And a cam driven member, and the transmission mechanism biasing means biases the transmission mechanism so that the cam and the cam driven member are not separated from each other. Various structures are characterized in that the cam presses the cam driven member by the movement of the first diaphragm driving member or the cam driven member presses the cam by the movement of the first diaphragm driving member. Includes a camera.

1 Camera Body 2 Shooting Lens 3 Lens Side Aperture Lever 5 CCD
101 control circuit 102 stepping motor driver 400 aperture mechanism 402 aperture lever 402f cam follower 403 aperture drive lever 405 aperture lever locking claw 407 charge lever 408 charge link plate 409 charge link lever 411 stepping motor 441 aperture PI blade lever 441a cam 442 aperture PI blade 443 Aperture PI 471 Aperture spring 483 Spring

Claims (5)

A first aperture driving member that drives the aperture of the lens in the aperture direction so that the aperture value of the lens aperture is set to an arbitrary aperture value from the open aperture value;
A second diaphragm driving member that drives the first diaphragm driving member such that the first diaphragm driving member drives the diaphragm of the lens in the narrowing direction;
A motor for driving the second diaphragm driving member;
Detecting means for detecting the start of movement of the first aperture driving member when the aperture value of the aperture of the lens is changed from an open aperture value to an arbitrary aperture value;
A transmission mechanism that transmits the movement of the first diaphragm driving member to the detection means;
Transmission mechanism urging means for urging the transmission mechanism,
The transmission mechanism is configured to increase the amount of movement of the first diaphragm driving member that is transmitted to the detection means in the vicinity of the position at which the first diaphragm driving member starts to move, compared to other positions. And a cam follower,
The transmission mechanism biasing unit biases the transmission mechanism so that the cam and the cam driven member are not separated from each other.
In the vicinity of the position at which the first diaphragm driving member starts to move, the transmission mechanism may cause the cam to press the cam follower member by the movement of the first diaphragm driving member or the first diaphragm driving member. A camera, wherein the cam follower member is configured to press the cam by movement. The camera of claim 1,
Drive member urging means for urging the diaphragm second drive member in the same direction as the direction in which the diaphragm second drive member drives the diaphragm first drive member;
The transmission mechanism reduces the urging force by the driving member urging means when the first diaphragm driving member is positioned at a position where the aperture value of the lens aperture is close to the open aperture value. In addition, the urging force of the transmission mechanism urging means is transmitted to the first diaphragm driving member and the second diaphragm driving member. The camera according to claim 2,
The driving member urging means reduces the urging force that urges the second diaphragm driving member as the second diaphragm driving member rotates in a direction to drive the first diaphragm driving member.
The transmission mechanism is configured to transmit the transmission mechanism to the first diaphragm driving member and the second diaphragm driving member as the second diaphragm driving member rotates in a direction to drive the first diaphragm driving member. A camera characterized by reducing the urging force caused by. The camera according to claim 3.
The transmission mechanism urging means is configured to increase the urging force of the driving member urging means when the second diaphragm driving member is further rotated in a direction to drive the first diaphragm driving member. A camera characterized by transmitting an urging force by the first diaphragm driving member and the second diaphragm driving member. In the camera according to any one of claims 1 to 4,
The detection means is a photo interrupter having a light emitting portion and a light receiving portion facing each other, and configured to detect light from the light emitting portion by the light receiving portion,
The transmission mechanism includes a slit disk provided with a slit part that transmits light emitted from the light emitting part toward the light receiving part, a non-slit part that blocks the light, and a lever that rotates the slit disk. Have
The cam and the cam follower member transmit the movement of the diaphragm first drive member to the lever,
The lever rotates the slit disk by the movement of the diaphragm first drive member transmitted from the cam and the cam driven member,
The photo interrupter detects whether the detection state of the light from the light emitting unit in the light receiving unit has changed due to rotation of the slit disk due to the movement of the first diaphragm driving member. A camera that detects the start of movement of a first drive member.

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