JP6004854B2 - Focal plane shutter, imaging apparatus and imaging system - Google Patents

Description

  The present invention relates to a focal plane shutter for an imaging apparatus.

  As a focal plane shutter for a camera, a slit formed by two shutter blades (a front curtain and a rear curtain) continuously exposes an imaging surface is known. These two blades are arranged in a blade chamber formed by three ground plates including a shutter ground plate. Each blade is formed of a plurality of arms, blades, and pivot members, and reciprocates between a position covering the opening of the shutter base plate and a retracted position. These shutter blades are operated by a driving member attached to the subject side of the shutter base plate. On the other hand, since the shutter blade is attached to the photographer side of the shutter base plate, the arm of the drive member and the shutter blade is connected by a drive pin that passes through the shutter base plate provided in the drive member. Each blade is actuated by its driving member, and the operation start timing is controlled by an electromagnet. The electromagnet is used in two ways. One is a tightening type and the other is a direct release type.

  In the focal plane shutter having such a configuration, it is known that the speed of the blades is relatively slow due to the influence of friction at the initial stage of driving of the blades. Further, the front curtain and the rear curtain before the start of traveling are in a state in which the front curtain is unfolded and the rear curtain is superimposed, so that the influence of friction in the initial traveling is different. In order to compensate for this, a method is known in which an auxiliary spring is used in the initial stage of driving and the front curtain and the rear curtain are set to appropriate travel curves (Patent Document 1).

JP 58-118628 A

  However, in the configuration of Patent Document 1, since the coil portion of the auxiliary spring is disposed within the rotation range of the drive lever, the drive lever has to be made higher by that amount, and the thickness of the entire shutter unit increases. .

  In view of such a problem, an object of the present invention is to make it difficult for the shutter unit to become thick even if an auxiliary spring that pushes the blade driving member only in the initial stage of travel of the blade group is disposed in addition to the driving spring.

  In order to achieve the above object, a focal plane shutter according to one aspect of the present invention includes a shutter base plate to which a front blade group and a rear blade group are rotatably attached, and a shaft that is rotatably supported by the shutter base plate. A leading blade driving member that drives the leading blade group from a standby position to a travel completion position by a biasing force of a leading blade driving spring, and is rotatably supported by the shutter base plate. A rear blade driving member that drives the rear blade group from the standby position to the travel completion position, and urging the rear blade driving member to rotate a predetermined amount when the rear blade driving member drives the rear blade group from the standby position. Until the leading blade driving member rotates and the leading blade driving member rotates a predetermined amount when the leading blade driving member drives the leading blade group from the standby position. A leading blade auxiliary spring, and the trailing blade auxiliary spring has a first coil portion, and the leading blade driving member and the trailing blade driving member of the shutter base plate are pivotally supported. The first coil portion is disposed outside the rotation locus of the trailing blade driving member, the leading blade auxiliary spring has a second coil portion, and the first surface of the shutter base plate. The second coil portion is disposed on the second surface opposite to the first blade group and outside the rotation locus of the leading blade group.

  According to the present invention, in addition to the drive spring, even if an auxiliary spring that boosts the blade drive member only in the initial stage of travel of the blade group is disposed, the shutter unit can be configured not to be thick.

1 is an external perspective view of an imaging apparatus equipped with a focal plane shutter that is an example of an embodiment of the present invention. It is a disassembled perspective view of a focal plane shutter. It is an external view of a focal plane shutter. It is a perspective view of the blade drive member of a focal plane shutter. It is a figure which shows the relationship between the blade | wing drive member of a focal plane shutter, a brake lever, and a cam gear. It is a perspective view of the upper plate | board of a focal plane shutter. It is a disassembled perspective view of the motor unit of a focal plane shutter. It is a figure which shows the operation | movement sequence of each member of a focal plane shutter. It is a figure which shows the state transition of a focal plane shutter. It is a figure which shows the state transition of a focal plane shutter. It is a figure which shows the state transition of a focal plane shutter. It is a figure which shows the state transition of a focal plane shutter. It is a figure which shows the state transition of a focal plane shutter. It is a figure which shows the state transition of a focal plane shutter. It is a figure which shows the state transition of a focal plane shutter. It is a figure which shows the state transition of a focal plane shutter. It is a figure which shows the state transition of a focal plane shutter. It is a figure which shows the state transition of a focal plane shutter. It is a figure which shows the state transition of a focal plane shutter. It is a figure which shows the member which concerns on the charge of the blade | wing drive member of a focal plane shutter.

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

  FIG. 1 is an external perspective view of an imaging apparatus equipped with a focal plane shutter which is an example of an embodiment of the present invention.

  The imaging device 101 is a digital camera that photoelectrically converts a subject image using an imaging element such as a CCD or CMOS to generate image information, and records the image information on an electronic recording medium such as an arbitrary memory.

  An imaging lens 201 that can be attached to and detached from the imaging apparatus 101 is integrated with the imaging apparatus 101 to constitute an imaging system.

  Next, the configuration of the focal plane shutter will be described.

  2A is an exploded perspective view of the focal plane shutter as viewed from the photographing light beam incident side, and FIG. 2B is an exploded perspective view of the focal plane shutter as viewed from the photographing light beam emission side.

  3A is a front view of the focal plane shutter viewed from the photographing light beam incident side, and FIG. 3B is a front view of the focal plane shutter viewed from the photographing light beam emission side. 3A, the upper base plate 20, the flexible substrate 22, the motor base plate 30, the gear cover 31, and the magnet cover 80 illustrated in FIG. 2A are omitted. In FIG. 3B, the cover plate 41 illustrated in FIG. 2B is omitted.

  The shutter base plate 1 is formed of a synthetic resin material, and an opening 1a through which a photographing light beam can pass is provided at the center. The shutter base plate 1 and the auxiliary base plate 2 are fastened by screws at fastening portions 1b, 1c, and 1d. The brake buffer member fixing shafts 1 h and 1 i are formed integrally with the shutter base plate 1 and protrude from holes provided in the auxiliary base plate 2.

  The auxiliary ground plane 2 is made of a metal material and reinforces the shutter ground plane 1. The auxiliary base plate 2 is caulked with a shaft formed of a metal material. A leading blade driving member shaft 2a, a trailing blade driving member shaft 2b, a leading blade cam gear shaft 2c, a trailing blade cam gear shaft 2d, and an idle gear shaft 2e are caulked on the surface of the auxiliary base plate 2 on the photographing light beam incident side. Further, a front blade main arm shaft 2f, a front blade sub arm shaft 2g, a rear blade main arm shaft 2h, and a rear blade sub arm shaft 2i are erected on the surface of the auxiliary base plate 2 on the photographing light beam emission side. Further, a front blade brake shaft 2j, a rear blade brake shaft 2k, a front blade brake guide shaft 2l, and a rear blade brake guide shaft 2m are erected on the surface of the auxiliary base plate 2 on the side where the photographing light beam is emitted.

  The movable end of the leading blade driving spring 5 is hooked on the leading blade driving member 3, and the fixed end is hooked on an adjuster 70 which is a spring force adjusting member. The movable end of the rear blade drive spring 6 is hung on the rear blade drive member 4, and the fixed end is hung on an adjuster 70 which is a spring force adjusting member. The adjuster 70 is rotated by rotating the worm gear 71, and the urging force of the leading blade driving spring 5 and the trailing blade driving spring 6 can be adjusted.

  The leading blade cam gear 8 and the trailing blade cam gear 9 are configured with the same number of teeth and are connected by the idle gear 12, so that they rotate at the same rotational speed and in the same rotational direction. As shown in FIG. 3A, the idle gear 12 is disposed outside the leading blade cam gear 8 and the trailing blade cam gear 9 from the opening 1a.

  An electromagnet 21 and a flexible substrate 22 are fixed to the upper base plate 20.

  The electromagnet 21 includes two electromagnets, a first electromagnet used when traveling the leading blade and a second electromagnet used when traveling the trailing blade. Further, the terminal 21 a of the electromagnet 21 is connected to a drive circuit (not shown) at the connection portion 22 a of the flexible substrate 22.

  The magnet cover 80 is fixed to the upper base plate 20 so as to cover the electromagnet 21, and protects the attracting portion of the electromagnet 21 and the attracting surface of the armature of each blade driving member from external dust.

  The space formed between the shutter base plate 1 and the upper base plate 20 is used as a traveling space for the leading blade driving member 3 and the trailing blade driving member 4.

  The rotational phase (rotational position) of the trailing blade cam gear 9 is detected by contacting the phase contact piece 13 provided on the trailing blade cam gear 9 with the phase pattern formed on the flexible substrate 22.

  A partition plate 40 and a cover plate 41 are attached to the shutter base plate 1 on the side where the photographing light beam exits. A front blade group 43 and a rear plate are disposed between the shutter base plate 1 and the partition plate 40 and between the partition plate 40 and the cover plate 41. A blade chamber in which the blade group 44 is arranged is formed. The opening 40 a of the partition plate 40 and the opening 41 a of the cover plate 41 have a shape similar to the opening 1 a of the shutter base plate 1. By superimposing these three openings, a rectangular exposure opening is formed, and the light flux passing through the shutter is limited. Reference numeral 42 denotes a spacer.

  The leading blade group 43 closes the opening 1a before the exposure operation. The main arm 43a and the sub arm 43b are rotatably attached to the leading blade main arm shaft 2f and the leading blade sub arm shaft 2g, respectively. 43c is the first blade forming a slit, 43d is the second blade, 43e is the third blade, and 43f is the fourth blade. Each blade is pivotally supported by the main arm 43a and the sub arm 43b so as to be rotatable by a pin 43g to form a parallel link. A leading blade backlash spring 43h is locked to the sub arm 43b in the direction in which the blades overlap.

  The rear blade group 44 closes the opening 1a when the exposure operation is completed. The main arm 44a and the sub arm 44b are rotatably attached to the rear blade main arm shaft 2h and the rear blade sub arm shaft 2i, respectively. 44c is the first blade forming a slit, 44d is the second blade, 44e is the third blade, and 44f is the fourth blade. Each blade is rotatably supported by a main arm 44a and a sub arm 44b so as to be rotatable by a pin 44g, thereby forming a parallel link. A leading blade backlash spring 44h is locked to the sub arm 44b in the direction in which the blade expands.

  When the trailing blade driving spring 6 drives the trailing blade driving member 4, the trailing blade auxiliary spring 62 is urged in an auxiliary manner in the driving traveling direction in the initial driving stage in the exposure operation of the trailing blade driving member 4. The rear blade auxiliary spring 62 is a torsion spring having a first coil portion, and the first coil portion of the rear blade auxiliary spring 62 is disposed on a spring guide shaft 1 e formed on the shutter base plate 1. That is, the rear blade auxiliary spring 62 is disposed on the surface (first surface) on which the leading blade driving member 3 and the rear blade driving member 4 of the shutter base plate 1 are pivotally supported. The coil portion is disposed outside the rotation locus of the trailing blade driving member 4. The movable end of the rear blade auxiliary spring 62 is hung on a rear blade operation pin 4a provided on the rear blade driving member 4 on the shutter base plate 1 side (A direction side in FIG. 2). Further, the fixed end of the rear blade auxiliary spring 62 is hooked on a spring hooking portion 1f provided on the shutter base plate 1 on the side away from the shutter base plate 1 (the B direction side in FIG. 2). Therefore, compared to the case where the first coil portion of the rear blade auxiliary spring 62 is within the rotation locus of the rear blade driving member 4, the rear blade driving member 4 can be disposed closer to the A direction, and the rear The blade driving member 4 can be configured low. Accordingly, the rear blade drive member 4 can be configured to be low and thin (or the number of windings of the rear blade drive spring can be increased), the rear blade operation pin 4a can be configured to be short, and inertia of the rear blade drive member 4 can be achieved. It is possible to reduce the size of the image.

  Reference numeral 60 denotes an auxiliary spring cover, and 61 denotes a leading blade auxiliary spring. When the leading blade driving spring 5 drives the leading blade driving member 3, the leading blade auxiliary spring 61 supplementarily biases the leading blade auxiliary spring 61 in the driving travel direction at the initial stage of driving in the exposure operation of the leading blade driving member 3. The leading blade auxiliary spring 61 is constituted by a torsion spring having a second coil portion. The second coil portion of the leading blade auxiliary spring 61 is disposed at a position where it does not overlap with the rotation locus of the sub arm 43b. That is, the leading blade auxiliary spring 61 is disposed on the surface (second surface) opposite to the surface on which the leading blade driving member 3 and the trailing blade driving member 4 of the shutter base plate 1 are pivotally supported. The second coil portion of the spring 61 is disposed outside the rotation locus of the sub arm 43b. Further, the movable end of the leading blade auxiliary spring 61 is hung on the brake operating pin 3 b (protruding portion) of the leading blade driving member 3. The locus of the brake operating pin 3b has a positional relationship that does not overlap with the sub arm 43b, and does not affect the arrangement of the sub arm 43b. That is, compared to the case where the coil portion of the leading blade auxiliary spring 61 is disposed between the leading blade driving member 3 and the shutter base plate 1, the leading blade driving member 3 can be configured to be low and thin.

  The half-moon rubber 65 is a half-moon-shaped cushioning member made of rubber or the like that comes into contact with the blade operating pin 3 a provided in the leading blade group 43 when the exposure operation of the leading blade group 43 is completed.

  The blade tip cushioning member 66 made of rubber or the like is configured such that the leading blade group 43 and the trailing blade group 44 abut upon completion of traveling.

  The brake buffer member 67 is formed so as to abut upon completion of travel of the brake lever 50 (braking member).

  Next, the structures of the leading blade driving member 3 and the trailing blade driving member 4 will be described in detail with reference to FIG. FIG. 4A is a perspective view of the leading blade driving member 3, and FIG. 4B is a top view of the leading blade driving member 3. 4C is a cross-sectional view of a portion used for adsorption to the electromagnet 21, and FIG. 4D is a cross-sectional view of a roller portion. 4E is a perspective view of the trailing blade driving member 4, and FIG. 4F is a top view of the trailing blade driving member 4. FIG. FIG. 4G shows a positional relationship among the leading blade driving member 3, the adjuster 70, the leading blade cam gear shaft 2c, and the electromagnet 21 during traveling, and FIG. 4H shows a sectional view thereof. FIG. 4 (i) shows a rear view of the adjuster 70.

  The leading blade driving member 3 is provided with a blade operating pin 3a, a brake operating pin 3b, a roller shaft 3c, an armature shaft 3d, an armature rubber 3e, an armature 3f, an armature guide 3g, and an armature spring 3h. The leading blade driving member 3 is rotatably supported by a leading blade driving member shaft 2 a that is crimped to the auxiliary base plate 2. When the leading blade driving member 3 is supported by the leading blade driving member shaft 2a, the brake operating pin 3b penetrates the auxiliary base plate 2 and protrudes into the blade chamber.

  The blade operating pin 3a engages with a hole provided in the main arm 43a.

  The brake operation pin 3 b and the roller shaft 3 c are formed integrally and are crimped to the leading blade driving member 3. By making these integral parts, the number of parts is reduced. A roller 7 is attached to the roller shaft 3c.

  The armature shaft 3d is crimped to the armature 3f. The armature guide 3g regulates the operation of the armature 3f and assists the adsorption to the electromagnet 21.

  The armature guide 3g is fixed to the leading blade driving member 3 by heat caulking. In the armature guide 3g, a guide portion 3g-1, a protective wall (second wall) 3g-2, and a heat caulking portion 3g-3 are formed.

  The adjuster 70 is formed with a gear 70a and a protective wall (first wall) 70b. The gear 70 a meshes with the worm gear 71. Further, the upper end 5 a of the leading blade driving spring 5 is hooked on the spring hooking groove 70 c of the adjuster 70, and the lower end 5 b is hooked on the spring hooking portion 3 j of the leading blade driving member 3, thereby rotating the worm gear 71 to rotate the leading blade. The biasing force to the drive member 3 is configured to be adjustable. Reference numeral 5 c denotes a coil portion of the leading blade drive spring 5.

  The arc-shaped protective wall 70 b is disposed between the leading blade drive spring 5 and the electromagnet 21. Therefore, it is possible to reduce dust and oil that passes through the gap and the side of the leading blade drive spring 5 and scatters from the roller 7 (first cam follower), the leading blade cam gear shaft 2c, and the trailing blade cam gear shaft 2d. Thereby, the adsorption | suction defect of the electromagnet 21 and a precision defect can be reduced.

  Further, since the protective wall 70b can be configured with a size that is substantially equal to or smaller than the gear 70a in the radial direction, it is possible to avoid an increase in the size of each blade driving member due to the arrangement of the protective wall 70b.

  The protective wall 3g-2 assists the function of the protective wall 70b. That is, by disposing the protective wall 3g-2 with a predetermined clearance from the protective wall 70b, it becomes possible to prevent dust and oil scattered from the outside further than the protective wall 70b.

  Further, since the protective wall 3g-2 protrudes toward the rotation center of the leading blade driving member 3, and the protective wall 70b is formed in an arc shape having the same rotational center as the leading blade driving member 3, the protective wall 3g-2 is protected. The gap between the wall 3g-2 and the protective wall 70b is easy to set to the minimum. The distance between the protective wall 3g-2 and the protective wall 70b is preferably 0.1 mm to 0.6 mm so as not to hinder the operation of the leading blade driving member 3 and to prevent entry of dust and oil.

  The rear blade drive member 4 is provided with a blade operation pin 4a, a brake operation pin 4b, a roller shaft 4c, an armature shaft 4d, an armature rubber 4e, an armature 4f, an armature guide 4g, and an armature spring 4h. The rear blade drive member 4 is rotatably supported by a rear blade drive member shaft 2b that is crimped to the auxiliary base plate 2. When the rear blade drive member 4 is supported by the rear blade drive member shaft 2b, the brake operation pin 4b penetrates the auxiliary base plate 2 and projects into the blade chamber.

  The rear blade operating pin 4a engages with a hole provided in the main arm 44a.

  The brake operation pin 4 b and the roller shaft 4 c are integrally formed and are crimped to the rear blade drive member 4. The roller 7 is attached to the roller shaft 7c.

  The armature shaft 4d is crimped to the armature 4f. The armature guide 4g regulates the operation of the armature 4f and assists the adsorption to the electromagnet 21.

  The armature guide 4g is fixed to the rear blade drive member 4 by heat caulking. The armature guide 4g is formed with a guide portion, a protective wall, and a heat caulking portion.

  The upper end 6 a of the rear blade drive spring 6 is hooked on the spring hook groove 70 c of the adjuster 70, and the lower end 6 b is hooked on the spring hook portion 4 j of the rear blade drive member 4, whereby the worm gear 71 is rotated to rotate the rear blade drive member. The urging force to 4 can be adjusted. 6 c is a coil portion of the trailing blade drive spring 6.

  The PI light shielding member 10 is fixed to each blade driving member by the compressed leading blade driving spring 5 and the fitting portion 10a. The PI light blocking unit 10b can block the detection light of the PI fixed to the upper base plate 20. Therefore, the brightness of PI is switched and the position of each blade drive member and each blade group is detected. Moreover, the roller drop-off prevention part 10c prevents the roller 7 from dropping from the roller shaft 3c.

  Next, the relationship among the blade driving member, the brake lever, and the cam gear will be described with reference to FIG.

  FIG. 5A shows a state in which the leading blade group 43 travels and the brake operating pin 3 b of the leading blade driving member 3 is in contact with the brake shaft contact portion 50 b of the brake lever 50.

  In FIG. 5A, the shutter base plate 1, the auxiliary base plate 2, and the like are not shown for easy viewing. Actually, the leading blade driving member 3, the trailing blade driving member 4, the leading blade cam gear 8, and the trailing blade cam gear 9 are attached to the auxiliary base plate 2 on the photographing light beam incident side (B direction side) in FIG. Yes. On the other hand, each member of the brake is attached to the photographing light beam emission side (A direction side) in FIG. 2 opposite to the side on which the leading blade driving member 3 and the like are attached to the auxiliary base plate 2.

  Further, as illustrated in FIG. 3, the brake lever 50 is disposed farther from the opening 1 a than the leading blade driving member 3 and the trailing blade driving member 4.

  The leading blade cam gear 8 includes a blade driving member charging cam 8a, a gear 8b, and a brake charging cam 8c.

  The trailing blade cam gear 9 includes a blade driving member charging cam 9a, a gear 9b, and a brake charging cam 9c.

  The brake return spring (braking member return spring) 58 is provided to reduce the brake charge load by returning the brake lever 50 against the frictional force in the direction opposite to the braking direction. Conventionally, the brake return spring has been disposed at a position where the coil portion overlaps the movable range of the brake lever. However, in this case, the height of the brake mechanism is increased and the thickness of the entire shutter unit is increased. Therefore, in the present embodiment, the coil portion of the brake return spring 58 is inserted into the brake guide shaft 2m outside the movable range of the brake lever 50, so that the arrangement of the brake lever 50 is kept low. At this time, the coil portion of the brake return spring 58 is not coaxial with the rotation center of the brake lever 50. As the brake lever 50 rotates, the contact position between the brake lever 50 and the brake return spring 58 changes one after another. In order to minimize the friction caused by this, a roller 57 (second cam follower) that can rotate the movable end of the spring. ). The fixed end of the brake return spring 58 is hung on the bent portions 41 b and 41 c of the cover plate 41.

  FIG. 5B is a cross-sectional view showing the configuration of the rear blade brake. The configuration of the brake for the leading blade is basically the same.

  The brake lever 50 is rotatably fitted to the rear blade brake shaft 2k while being sandwiched between the friction members 51. Moreover, the brake lever 50 receives the pressure of the leaf | plate spring 53 via the stationary plate 52 which fits around the rear-blade brake shaft 2k so that rotation is impossible.

  The roller 57 is engaged with the brake lever 50. The movable end of the brake return spring 58 is hung on the spring hook portion 57a. The cam follower 57b slides with the cam 8c of the leading blade cam gear 8 during the charge sequence to rotate the brake lever 50 to a predetermined standby state.

  Conventionally, this brake charge operation has been performed via the blade driving member. However, the loss of energy transmission can be reduced by performing the brake charge operation directly with the cam gear.

  During the braking operation, the brake operating pin 3b of the leading blade driving member 3 protrudes from the surface on the photographing light beam incident side of the auxiliary base plate 2 to the surface on the photographing light beam emission side and contacts the contact surface 50b of the brake lever 50. At this time, since the brake operation pin 3b rubs against the contact surface 50b, there is a possibility that scraps may be generated as the number of brake operations increases. In the present embodiment, in view of this point, the brake mechanism itself is arranged in the blade chamber sufficiently away from the electromagnet, so that even if scraps are generated, adverse effects on the electromagnet can be minimized.

  The brake lever 50 stops by colliding with a brake buffer member 67 fixed to the brake buffer member fixing shafts 1h and 1i formed on the shutter base plate 1 after rotating by a predetermined amount. In addition, the wider the brake operating range, the more energy generated by the drive spring is wasted. Therefore, the brake operating range is set to a predetermined range immediately before the completion of traveling.

  The fastening means 55 is composed of a nut or a screw for fastening, and the adjustment plate 56 sets the charge amount of the leaf spring 53 by fastening the fastening means 55 and adjusts the pressure of the leaf spring 53.

  FIG.5 (c) is the figure which looked at Fig.5 (a) from the top.

  The PI light shielding portion 10 b of the PI light shielding member 10 fixed to the leading blade driving member 3 is disposed between the cam 8 a and the gear 8 b of the leading blade cam gear 8. The PI light shielding member 10 fixed to the leading blade driving member 3 can maintain the clearance between the cam 8a and the gear 8b of the leading blade cam gear 8, and the PI light shielding member 10 so as to operate integrally with the leading blade driving member 3. Can be arranged.

  The PI light shielding portion 10b of the PI light shielding member 10 fixed to the rear blade driving member 4 is disposed between the cam 9a and the gear 9b of the rear blade cam gear 9. The PI light shielding member 10 fixed to the rear blade driving member 4 can maintain the clearance between the cam 9 a and the gear 9 b of the rear blade cam gear 9 and operates integrally with the rear blade driving member 4. Can be arranged.

  FIG. 6 is a perspective view of the upper base plate 20. 6A is a perspective view of the surface on the photographing light beam exit side, and FIG. 6B is a perspective view of the surface on the photographing light beam incident side.

  The leading blade PI (first optical detecting member) 11a and the trailing blade PI 11b (second optical detecting member) detect the rotational positions of the leading blade driving member 3 and the trailing blade driving member 4, respectively. Reference numeral 68 denotes a rear blade drive member cushioning member.

  The leading blade PI11a and the trailing blade PI11b are connected to the PI connecting portion 22b of the flexible substrate 22 that has passed through the hole or groove formed in the upper base plate 20. The hole or groove of the upper base plate 20 is formed at a position overlapping with a plane connecting the leading blade driving member shaft 2a and the trailing blade driving member shaft 2b.

  Further, the PI has a smaller radius of rotation of the PI light-shielding portion as it approaches the rotation center of the PI light-shielding member. Therefore, the PI of (2) shown in FIG. 6C than the arrangement of (1) shown in FIG. The arrangement is reduced in size and arranged.

  In the present embodiment, a line connecting the light projecting portion and the light receiving portion of the leading blade PI11a is substantially parallel to the rotational axis of the leading blade driving member 3 between the leading blade driving member shaft 2a and the trailing blade driving member shaft 2b. In addition, the leading blade PI11a is arranged. As shown in FIG. 3A, the distance from the opening 1a to the line connecting the electromagnets 21 of the leading blade and the trailing blade is the rotation center of the leading blade cam gear 8 and the rotation of the trailing blade cam gear 9 from the opening 1a. Shorter than the line connecting the center. The leading blade PI11a and the trailing blade PI11b are arranged between a line connecting the electromagnets 21 of the leading blade and the trailing blade and a line connecting the rotation center of the leading blade cam gear 8 and the rotation center of the trailing blade cam gear 9. . Thereby, since PI can be brought close to the rotation center of the detection component, the light shielding member 10b can be reduced in size, and the inertia of the leading blade driving member 3 can also be reduced. Also, PI can be arranged without increasing the size of the shutter unit. The rear blade PI11b is also disposed so as to overlap the rotation range of the rear blade driving member 4 in a plane, and the PI can be disposed without increasing the size of the shutter unit.

  Further, the relative positional relationship of the leading blade PI11a with respect to the leading blade driving member 3 and the relative positional relationship of the trailing blade PI11b with respect to the trailing blade driving member 4 are the same. Therefore, even if the PI light shielding member 10 is formed in the same shape, it can be used for both the leading blade driving member 3 and the trailing blade driving member 4.

  FIG. 7 is an exploded perspective view of the motor unit.

  The motor base plate 30 is fastened to the upper base plate 20 with screws, and the gear cover 31 and the motor 32 are fastened to the motor base plate 30 with screws.

  The rotation from the motor 32 is transmitted in the order of the pinion gear 33, the first reduction gear 34, the second reduction gear 35, the leading blade cam gear 8, the idle gear 12, and the trailing blade cam gear 9.

  Since the rear blade is held by the rear blade cam gear 9 in the live view state, the phase contact piece 13 is arranged on the rear blade cam gear 9 to reduce the positional deviation between the idle gear 12 and the cam gear. Therefore, the phase of the live view can be made narrower than when the phase contact piece 13 is arranged on the leading blade cam gear 8. As a result, during normal release, the cam rotation angle when passing through the live view phase is reduced, so that the energization time of the motor 32 can be reduced and the release time lag can be shortened.

  The first reduction gear 34 is rotatably supported on the shaft 30 a of the motor base plate 30, and the second reduction gear 35 is rotatably supported on the shaft 30 b of the motor base plate 30. The shaft 30b is fitted with the auxiliary base plate 2 at the tip end of the shaft 30b, and keeps the distance between the gear shaft and the leading blade cam gear shaft 2c crimped to the auxiliary base plate 2 within a predetermined range.

  The operation of each component will be described with reference to FIGS.

  FIG. 8A shows an operation sequence of each component in normal shooting, and FIG. 8B shows an operation sequence of each component in live view shooting. 9 to 19 are diagrams showing state transition of the focal plane shutter, and FIG. 20 is a diagram illustrating members related to charging of the blade driving member of the focal plane shutter.

First, the operation of each component during normal release will be described.
(1) Standby state before release In FIG. 8 (1), the focal plane shutter is in the standby position before release. The state of each component is shown in FIG. In this state, the roller 7 of the leading blade driving member 3 is in contact with the cam top of the cam 8 a of the leading blade cam gear 8. The roller 7 of the trailing blade driving member 4 is in contact with the cam top of the cam 9 a of the trailing blade cam gear 9. Therefore, the leading blade cam gear 8 locks the leading blade driving member 3 in a right-handed state shown in FIG. The trailing blade cam gear 9 locks the trailing blade driving member 4 in a state of being rotated clockwise as shown in FIG.

  At this time, in order to guarantee the attracted state of the armatures 3f and 4f and the electromagnet 21, the armatures 3f and 4f are attracted by the electromagnet 21, and the leading blade driving member 3 and the trailing blade driving member 4 are more than the positions where they can be held. Is rotating. This state is also called an overcharge state. In the case of the leading blade driving member 3, this overcharge is absorbed by a gap formed between the armature rubber 3 e and the leading blade driving member 3.

Further, in order to stabilize the position of the armature from the start of overcharge to the release, the armatures 3f and 4f are urged by the armature springs 3h and 4h.
(2) Canceling overcharge When a release signal is received from the standby state before release in (1) of FIG. 8, energization of the motor 32 is started, and the leading blade cam gear 8 and trailing blade cam gear 9 start rotating. At the same time, energization of the front and rear electromagnets 21 is started.

  At this time, the leading blade cam gear 8 and the trailing blade cam gear 9 both turn clockwise from the state of FIG. Thus, after the cam 8a of the leading blade cam gear 8 and the roller 7 of the leading blade driving member 3 are not in contact with each other, the cam 9a of the trailing blade cam gear 9 and the roller 7 of the trailing blade driving member 4 are not in contact with each other. Thus, the leading blade cam gear 8 and the trailing blade cam gear 9 are stopped. At this time, the leading blade driving member 3 and the trailing blade driving member 4 are unlocked and rotate, but the leading blade and trailing blade electromagnets 21 are energized, and the armatures 3f and 4f are leading blade and trailing blade electromagnets 21. So that it stops after rotating a predetermined amount. That is, the gap between the armature rubber 3e and the leading blade driving member 3 caused by overcharging disappears, and the leading blade driving member 3 is rotated and held until the armature rubber 3e is compressed and balanced with the leading blade driving spring 5. Is done. Similarly, the gap between the armature rubber 4e and the rear blade drive member 4 is eliminated, and the rear blade drive member 4 is rotated clockwise and held until the armature rubber 4e is compressed and the rear blade drive spring 6 is balanced.

When the motor 32 further rotates, the focal plane shutter transitions to (2) in FIG. The state of each component at that time is a state in which the overcharge release shown in FIG. 10 is performed.
(3) Energization holding release When the motor 32 stops and a predetermined time elapses, the electromagnets 21 of the leading blade and the trailing blade release the energization at arbitrary intervals. The difference between the energization release times is equivalent to the exposure time. The exposure time may be longer or shorter than the traveling time of the leading blade group 43, but here, the case where the exposure time is longer than the traveling time of the leading blade group 43 will be described.

  First, energization of the electromagnet 21 on the leading blade side is released. As a result, the leading blade driving member 3 is urged by the leading blade driving spring 5 and the leading blade auxiliary spring 61 to start clockwise rotation from the state of FIG. After the leading blade driving member 3 has rotated by a predetermined amount, the leading blade auxiliary spring 61 comes into contact with a stopper (not shown), thereby ending the biasing to the leading blade driving member 3.

  Thereafter, the leading blade driving spring 5 biases the leading blade driving member 3. Subsequently, the brake operating pin 3b of the leading blade driving member 3 comes into contact with the brake lever 50 ((3) in FIG. 8). FIG. 11 shows this state.

  After (3) in FIG. 8, the leading blade drive member 3 travels between the friction members 51 while pressing the brake lever 50 to which the friction brake is applied until the travel completion position.

  The leading blade driving member 3 travels while receiving friction from the brake lever 50, and the traveling is completed when the blade operating pin 3a contacts the half moon rubber 65 (FIG. 8 (4)). FIG. 12 shows this state.

  The leading blade group 43 cannot suddenly stop, overruns while being deformed, and the first blade 43c collides with the blade tip cushioning member 66 disposed at a predetermined distance. The brake lever 50 also overruns and collides with the brake buffer member 67.

  Thereafter, the trailing blade driving member 4 is urged by the trailing blade driving spring 6 and the trailing blade auxiliary spring 62, and starts rotating clockwise from the state of FIG. The trailing blade driving member 4 is substantially the same as the traveling of the leading blade driving member 3.

  First, when the rear blade driving member 4 rotates by a predetermined amount, the rear blade auxiliary spring 62 comes into contact with a stopper (not shown), and the biasing to the rear blade driving member 4 is finished.

  Thereafter, the trailing blade driving spring 6 biases the trailing blade driving member 4. Subsequently, the brake operation pin 4b (protrusion) of the rear blade drive member 4 comes into contact with the brake lever 50 (FIG. 8 (5)). FIG. 13 shows this state.

  After the state shown in FIG. 13, the rear blade drive member 4 travels between the friction members 51 while pressing the brake lever 50 to which the friction brake is applied until the travel completion position.

  The rear blade drive member 4 travels while receiving friction from the brake lever 50, and the travel is completed when the brake lever 50 collides with the brake buffer member 67 (FIG. 8 (6)). FIG. 14 shows this state.

  The rear blade group 44 cannot suddenly stop, overruns while deforming, and the first blade 44c collides with a blade tip cushioning member 66 disposed at a predetermined distance. Further, the rear blade driving member 4 and the bent portion to which the armature 4f is attached are also slightly deformed and overrun by the weight of the armature 4f. As a result, the rubber collision portion 4 i of the rear blade drive member 4 collides with a buffer member 68 provided on the upper base plate 20 and separated by a predetermined distance.

Further, after the buffer member 68 is deformed, it collides with the screw seat 1j of the shutter base plate 1. Since the trailing blade driving member 4 is made of a metal plate press, the end surface usually has a rough surface such as a shear surface or a fracture surface. The rubber collision part 4 i uses a bent flat part of the rear blade driving member 4, and the generation of dust is suppressed as compared with the case where the end surface of the rear blade driving member 4 collides with the buffer member 68.
(4) Lead blade driving member charge After a predetermined time has elapsed since the trailing blade driving member 4 traveled, the motor 32 is energized. The leading blade cam gear 8 and trailing blade cam gear 9 start clockwise in the state of FIG. 14A and reach the position where the leading blade drive member 3 is charged (FIG. 8 (7)). FIG. 15 shows the state at this time.

  The cam 8c for brake charging of the leading blade cam gear 8 does not reach the position where the brake lever 50 is charged. In the travel completion state of the leading blade group 43, the brake lever 50 and the brake operating pin 3b are in contact with each other. Therefore, if the leading blade driving member 3 is not charged in advance, the leading blade driving member 3 is indirectly charged by brake charging. In the present embodiment, the brake charge cam 8c is difficult to have a shape suitable for a large charge load due to shape restrictions, and it is necessary to avoid charging the leading blade drive member 3 indirectly. Therefore, the cam 8c is set so that the leading blade driving member 3 and the brake lever 50 are charged in order by the rotation of the leading blade cam gear 8.

20A shows only the leading blade driving member 3, the trailing blade driving member 4, the leading blade cam gear 8, the trailing blade cam gear 9, and the idle gear 12 related to the charging operation in FIG. 8 (7) from the cam surface side. FIG. The roller 7 of the leading blade driving member 3 is in contact with the cam surface 8 a 1 that charges the cam 8 a of the leading blade cam gear 8. When the roller 7 slides on the cam surface 8a1, charging of the leading blade driving member 3 is started. The position of the leading blade cam gear 8 at this time is X1.
(5) Leading blade brake charge The state in which the leading blade cam gear 8 further turns rightward from FIG. 15A is the state of FIG. At this time, the leading blade driving member 3 is in the middle of charging, and there is a gap between the brake lever 50 and the brake operating pin 3b. Therefore, the brake charging cam 8c can charge only the brake lever 50. At this time, the brake return spring 58 reduces the brake charge load by returning the brake lever 50 against the frictional force in the direction opposite to the braking direction. Further, after the brake is charged, the locking of the brake roller 57 by the cam 8c is immediately released, but the brake friction force is adjusted so that the brake lever 50 does not receive further force by the brake return spring 58.
(6) Rear blade drive member charge The state in which the rear blade cam gear 9 is further turned to the right from FIG. 16A is the state of FIG. To reach.

  Since the relationship between the trailing blade driving member 4 and the brake lever 50 can be said to be the same as that of the leading blade driving member 3, the trailing blade driving member 4 is charged prior to charging the brake lever 50.

  20B shows only the leading blade driving member 3, the trailing blade driving member 4, the leading blade cam gear 8, the trailing blade cam gear 9, and the idle gear 12 related to the charging operation in FIG. 8 (9) from the cam surface side. FIG. In FIG. 20B, the roller 7 of the leading blade driving member 3 reaches the cam top of the cam surface 8 a 1 of the leading blade cam gear 8. The position of the leading blade cam gear 8 at this time is X2. The charge rotation angle X2-X1 of the leading blade cam gear 8 until the leading blade driving member 3 is charged is θ1. On the other hand, the roller 7 of the trailing blade driving member 4 comes into contact with the cam surface 9a1 that charges the cam 9a of the trailing blade cam gear 9, and charging of the trailing blade driving member 4 is started. The position of the trailing blade cam gear 9 at this time is X3.

In order to keep the opening shielded during charging of the leading blade driving member 3 and the trailing blade driving member 4, charging is performed in the order of the leading blade driving member 3 and the trailing blade driving member 4.
(7) Rear blade brake charge The state in which the rear blade cam gear 9 further turns right from the state of FIG. 17A is the state of FIG. 18 (FIG. 8 (10)), and charging of the brake lever 50 is started. . At this time, the trailing blade driving member 4 is in the middle of charging, and there is a gap between the brake lever 50 and the brake operating pin 4b. Therefore, the brake charging cam 9c can charge only the brake lever 50.

  When the trailing blade brake charge is completed, the state shown in FIG. 19 (FIG. 8 (11)) is obtained.

  FIG. 20C is a view of only the leading blade driving member 3, the trailing blade driving member 4, the leading blade cam gear 8, the trailing blade cam gear 9, and the idle gear 12 related to the charging operation as seen from the cam surface side. In FIG. 20 (c), the roller 7 of the trailing blade driving member 4 reaches the cam top of the cam surface 9 a 1 of the trailing blade cam gear 9. At this time, the position of the rear cam gear 9 is set to X4. The charge rotation angle X4-X3 of the rear cam gear 9 until the rear blade drive member 4 is charged is θ2. As described above, the R shape of the cam surface 9a1 of the trailing blade cam gear 9 is larger than that of the cam surface 8a1 of the leading blade cam gear 8, and the charge rotation angle is θ1 <θ2.

  Here, since the rear blade cam gear 9 transmits the rotation from the motor 32 via the leading blade cam gear 8 and the idle gear 12, the transmission efficiency is lower than that of the leading blade cam gear 8. Therefore, if the same charge rotation angle is set, the current consumption during charging of the trailing blade driving member 4 becomes larger than that of the leading blade driving member 3. In this embodiment, by setting the charge rotation angle to θ1 <θ2, the current consumption during charging of the leading blade driving member 3 and the trailing blade driving member 4 is made substantially the same. As a result, the maximum value of the current consumption is lowered to reduce the load on the battery of the imaging apparatus 101, and for example, the photographing enabled state can be maintained even when the current consumption of the motor 32 increases in a low temperature environment.

It is desirable that the charge rotation angle θ2 of the trailing blade cam gear 9 is as follows. The charge torque of the leading blade driving member is T1, the charging torque of the trailing blade driving member is T2, and the transmission efficiency of each gear is η. In the present embodiment, since the trailing blade cam gear 9 is engaged with gears at two locations via the idle gear 12, the transmission efficiency is η ² .

  Furthermore, by continuing energization to the motor 32, it returns to the state of Fig.9 (a) and a series of sequences are completed.

Next, the movement of each component during live view shooting will be described. Description of common symbols and pictures is omitted.
(1) Standby state before release It is the same as the standby state before release during normal shooting, and is in the state of FIG.
(2) Live View Phase Cancellation Upon receipt of the release signal, energization of the motor 32 is started, and the leading blade cam gear 8 and trailing blade cam gear 9 start to rotate clockwise from the state shown in FIG. The difference from the normal release is that although the electromagnet 21 on the rear blade side is energized, the electromagnet 21 on the front blade is not energized. The range after the overcharge release of the leading blade cam gear 8 and before the start of the overcharge release of the trailing blade cam gear 9 is called the live view phase.

When the clockwise rotation of the leading blade cam gear 8 is started in the state of FIG. 9A, the contact between the cam 8a of the leading blade cam gear 8 and the roller 7 of the leading blade driving member 3 is released. At this time, since the electromagnet 21 on the leading blade side is not energized, the leading blade driving member 3 travels to the travel completion position (FIG. 8 (12)). On the other hand, the contact between the cam 9a of the trailing blade cam gear 9 and the roller 7 of the trailing blade driving member 4 is released. At this time, the electromagnet 21 on the rear blade side is energized, and the roller 7 of the rear blade driving member 4 is locked by the cam 9 a of the rear blade cam gear 9.
(3) Release of energization retention When a predetermined time elapses after the motor is stopped, an image sensor (not shown) starts electronic front curtain travel. The description of the electronic front curtain travel is omitted. Following the start of the electronic front curtain travel, the energization of the electromagnet 21 on the rear blade side is released. The exposure time of the image sensor is determined by the electronic front curtain simulating the front blade and the timing of releasing the energization of the electromagnet 21 on the rear blade side. The rear blade drive member 4 travels to the travel completion position by de-energizing the electromagnet 21 on the rear blade side.

  Subsequent release sequences are basically the same as those in normal shooting, and thus description thereof is omitted.

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

DESCRIPTION OF SYMBOLS 1 Shutter base plate 2 Auxiliary base plate 3 Front blade drive member 4 Rear blade drive member 5 Front blade drive spring 6 Rear blade drive spring 43 Front blade group 44 Rear blade group 61 Front blade auxiliary spring 62 Rear blade auxiliary spring

Claims (6)

A shutter base plate to which the front blade group and the rear blade group are rotatably attached;
A leading blade driving member rotatably supported on the shutter base plate and driving the leading blade group from a standby position to a travel completion position by a biasing force of a leading blade driving spring at the time of photographing;
A rear blade drive member rotatably supported on the shutter base plate and driving the rear blade group from a standby position to a travel completion position by an urging force of a rear blade drive spring at the time of photographing;
A rear blade auxiliary spring that biases the rear blade driving member until it rotates a predetermined amount when the rear blade driving member drives the rear blade group from the standby position;
A leading blade auxiliary spring that biases the leading blade driving member until it rotates a predetermined amount when the leading blade driving member drives the leading blade group from the standby position;
The rear blade auxiliary spring has a first coil portion, and is a first surface on which the leading blade driving member and the trailing blade driving member of the shutter base plate are pivotally supported, and the rear blade driving member Arranging the first coil part outside the rotation locus;
The leading blade auxiliary spring has a second coil portion, and is a second surface opposite to the first surface of the shutter base plate, and the second blade blade is outside the rotation locus of the leading blade group. A focal plane shutter comprising a coil portion. A braking member provided on the second surface, which is in contact with a projecting portion projecting from the leading blade driving member through the shutter base plate and projecting to the second surface in order to stop the operation of the leading blade group; Have
The focal plane shutter according to claim 1, wherein a movable end of the leading blade auxiliary spring is hung on the protruding portion. A cam follower for charging the leading blade driving member to a standby position;
The leading blade driving member includes a shaft for holding the cam follower,
The focal plane shutter according to claim 1, wherein the protruding portion is formed coaxially with a shaft for holding the cam follower.   The focal plane shutter according to any one of claims 1 to 3, wherein the rear blade auxiliary spring and the front blade auxiliary spring are torsion springs. An image sensor that photoelectrically converts a subject image to generate image information;
An imaging apparatus comprising: the focal plane shutter according to any one of claims 1 to 3. An imaging device according to claim 5;
An imaging system comprising: a photographic lens that can be attached to and detached from the imaging device.