JP7211736B2 - Focal plane shutter and imaging device - Google Patents

Description

One aspect of the present invention relates to a focal plane shutter and the like used in an imaging device such as a camera.

In a focal plane shutter that exposes an image sensor by opening and closing an aperture (also called an exposure aperture) with shutter blades, the shutter blades placed in a blade chamber formed between a base plate and a cover plate are driven by a drive mechanism. By driving, the opening/closing state of the opening is changed to perform exposure. In such a focal plane shutter, as the blades are driven, the components of the drive mechanism arranged outside the blade chamber slide against each other and rub against each other to generate abrasion powder, etc., and the abrasion powder is generated in the travel space of the blade. Intrusion may occur, and abrasion powder may adhere to the image sensor. If abrasion powder enters the running space of the blade, it may affect the running of the blade. In addition, adhesion of abrasion powder to the imaging element may lead to deterioration in the image quality of the captured image. Patent Document 1 discloses a configuration in which a wall is provided to prevent abrasion powder generated during operation of the focal plane shutter from entering the blade chamber. Patent Literature 2 discloses a configuration in which a shielding portion capable of shielding the blade through-hole is provided. Patent Literature 3 discloses a configuration in which abrasion powder or the like is captured by an adhesive sheet. Patent Document 4 discloses a focal plane shutter having a configuration in which adhesive members are provided on the surfaces of a plurality of arms.

Japanese Patent Application Laid-Open No. 2003-270700 Japanese Patent Application Laid-Open No. 2001-296581 JP 2003-280066 A JP 2015-210494 A

However, the conventionally configured focal plane shutter may not sufficiently suppress the scattering of abrasion powder, and there is a demand for a focal plane shutter configured to more effectively suppress the scattering of abrasion powder.

The present invention employs the following means to solve the above problems. In the following description, reference numerals and the like in the drawings are added in parentheses to facilitate understanding of the invention, but each component of the present invention is not limited to these added descriptions. It should be interpreted broadly to the extent that a trader can technically understand.

One means of the present invention is
a base plate (1) having an opening (1a), through holes (11, 12), and pivot shafts (13, 14);
Blades (4, 5) that switch between a state of covering the opening and a state of opening the opening;
Arms (61, 71, 161, 261, 271) that rotate about the rotation shaft and are connected to the blades;
a driving pin (81, 82) inserted through the through-hole, moving in the through-hole forming area, and connected to the arm;
The arm has an extended portion (61b, 71b, 161b, 261b, 271b) formed to cover 1/2 or more of the through hole when the blade covers the opening,
It is a focal plane shutter.

According to the focal plane shutter having the above configuration, abrasion powder such as metal or resin generated outside the blade chamber passes through the through holes and enters the blade chamber, or passes through the blade chamber and adheres to the image sensor. can be suppressed. As a result, it is possible to suppress malfunction of the blades caused by abrasion powder and deterioration of the image quality of the captured image. In addition, compared to the conventional configuration of Patent Document 4, the provision of an expanded portion that covers 1/2 or more of the through hole can effectively suppress the intrusion of abrasion powder into the blade chamber. It's becoming

In the above focal plane shutter, preferably
The extensions (61b, 71b, 161b, 261b, 271b) are formed so as not to protrude from the base plate in plan view when the blades open the openings.

According to the focal plane shutter having the above configuration, it is possible to prevent the extended portion from protruding from the area of the main plate of the focal plane shutter, coming into contact with other components, and being damaged.

In the above focal plane shutter, preferably
The extension portion is formed to cover the entire through hole (11, 12) when the blade covers the opening.

According to the focal plane shutter having the above configuration, it is possible to more effectively suppress the abrasion powder from entering the blade chamber and the vicinity of the imaging element.

In the above focal plane shutter, preferably
The extension portion protrudes from the other portions (61d, 161d, 261d) of the arm and is formed to extend in an arc shape along the formation region of the through hole.

According to the focal plane shutter having the above configuration, the extended portion can have an effective shape to cover the through hole, so that the intrusion of abrasion powder into the blade chamber and the vicinity of the imaging element can be more effectively suppressed. be able to.

In the above focal plane shutter, preferably
An adhesive is arranged on the surface of the extended portion on the through hole side.

According to the focal plane shutter having the above configuration, it is possible to suppress re-scattering of abrasion powder adhering to the extended portion due to repeated travel of the blades. As a result, it is possible to more effectively suppress the abrasion powder from entering the vicinity of the blade chamber and the imaging element.

In the above focal plane shutter, preferably
A permanent magnet is arranged on the surface of the extended portion on the through hole side.

According to the focal plane shutter having the above configuration, the metal powder generated by friction can be captured, so that the metal powder can be prevented from scattering due to repeated travel of the blades. As a result, it is possible to effectively prevent the metal powder from entering the blade chamber and the vicinity of the imaging element.

In the above focal plane shutter, preferably
The extended portion has recesses (61c, 71c) formed on the surface on the through hole side.

According to the focal plane shutter having the above configuration, the wear powder can be easily confined in the concave portion, and the wear powder can be more effectively suppressed from entering the blade chamber and the vicinity of the imaging element.

In the above focal plane shutter, preferably
An adhesive is placed in the recesses (61c, 71c).

According to the focal plane shutter having the above configuration, the abrasion powder can be captured by the adhesive in the concave portion, so that the abrasion powder adhering to the expanded portion is more effectively prevented from scattering again due to repeated travel of the blades. can be suppressed to As a result, it is possible to more effectively suppress the abrasion powder from entering the vicinity of the blade chamber and the imaging element.

Or, in the above focal plane shutter,
Permanent magnets are arranged in the recesses (61c, 71c).

According to the focal plane shutter having the above configuration, since the metal powder can be captured by the permanent magnet in the concave portion, it is more effective to prevent the metal powder adhering to the extended portion from scattering again due to repeated travel of the blades. can be suppressed to As a result, it is possible to more effectively prevent the metal powder from entering the blade chamber and the vicinity of the imaging element.

In the above focal plane shutter, preferably
The extension portion has wall portions (261c, 271c) extending toward the through hole on the surface on the through hole side.

According to the focal plane shutter having the above configuration, even if abrasion powder adhering to the extended portion tends to scatter when the blades are repeatedly driven, the wall portion can suppress the scatter. As a result, it is possible to more effectively suppress the abrasion powder from entering the vicinity of the blade chamber and the imaging element.

In the above focal plane shutter, preferably
The walls (261c, 271c) are formed at or near the edge of the extension along the direction in which the through hole extends.

According to the focal plane shutter having the above configuration, it is possible to form the wall relatively easily, and to effectively suppress the wear powder adhering to the extended portion from entering the blade chamber and the vicinity of the imaging element.

In the above focal plane shutter, preferably
The walls are formed at both edges of the extension.

According to the focal plane shutter having the above-described configuration, the wall section can more effectively suppress the wear powder adhering to the extended section from entering the blade chamber and the vicinity of the imaging element.

In the above focal plane shutter, preferably
The wall portion is formed so as to surround part or all of a surface of the extension portion on the through hole side.

According to the focal plane shutter having the above configuration, the wall surrounding the through-hole on the entire periphery can more effectively prevent abrasion powder adhering to the extended portion from entering the blade chamber and the vicinity of the imaging element.

Any one of the focal plane shutters described above is suitably applied to an imaging device such as a camera.

According to the imaging apparatus as described above, it is possible to prevent dust such as abrasion powder from scattering and entering the blade chamber or from adhering to the imaging element. As a result, it is possible to prevent deterioration in the quality of an image captured by the imaging device while preventing operational problems caused by wear debris.

FIG. 1 is a plan view of a focal plane shutter before blade travel according to Embodiment 1. FIG. FIG. 2 is a plan view of the focal plane shutter after the blade travels according to the first embodiment. FIG. 3 is a plan view of the main arm for leading blades in Embodiment 1. FIG. 4 is a cross-sectional view of the extended portion of the main arm for the leading blade in Embodiment 1. FIG. FIG. 5 is a plan view of a front blade main arm in a comparative example. FIG. 6 is a plan view of a front blade main arm in a modified example. FIG. 7 is a plan view of the focal plane shutter before the blade travels according to the second embodiment. FIG. 8 is a plan view of the focal plane shutter after blade travel according to the second embodiment. FIG. 9 is a plan view of the main arm for leading blades in Embodiment 2. FIG. FIG. 10 is a cross-sectional view of an extended portion of the front blade main arm in Embodiment 2. FIG.

The focal plane shutter of the present invention is used in an image pickup apparatus such as a digital camera. One of the characteristics is the composition of the department.

An embodiment according to the present invention will be specifically described according to the following configuration with reference to the drawings. However, the embodiment described below is merely an example of the present invention, and the technical scope of the present invention should not be construed in a limited manner. In addition, in each drawing, the same code|symbol is attached|subjected to the same component, and the description may be abbreviate|omitted.
1. Embodiment 1
2. Embodiment 2
3. Supplementary matter

<1. Embodiment 1>
First, Embodiment 1 of the present invention will be specifically described.

1 and 2 are plan views of the focal plane shutter of this embodiment, FIG. 1 showing the state before the blades travel, and FIG. 2 showing the state after the blades travel. FIG. 3 is an enlarged plan view of the leading blade main arm 61. FIG. FIG. 4 is a sectional view of the extended portion 61b of the main arm 61 for the front blade.

As shown in FIGS. 1 and 2, the focal plane shutter of the present embodiment includes a base plate 1, a cover plate 2, an intermediate plate 3, a front blade 4, a rear blade 5, a main arm 61 for the front blade, a secondary blade for the front blade. It comprises an arm 62 , a trailing blade main arm 71 , a trailing blade secondary arm 72 , a leading blade driving pin 81 and a trailing blade driving pin 82 . The leading blade 4 and the trailing blade 5 may be collectively referred to as "blades". The leading blade main arm 61 and the trailing blade main arm 71 may be collectively referred to as "main arms". The leading blade follower arm 62 and the trailing blade follower arm 72 may be collectively referred to as "follower arms". The leading blade drive pin 81 and the trailing blade drive pin 82 may be collectively referred to as "drive pins".

<Main plate 1>
The base plate 1 is a substrate portion of the focal plane shutter and has a substantially rectangular opening 1a. The opening 1a may be of any shape other than rectangular. As shown in FIGS. 1 and 2, on the side of the opening 1a of the base plate 1 (on the right side of the drawing), there is a drive pin 81 for the front blade and a drive pin 82 for the rear blade outside the blade chamber, which will be described later. part is installed. The drive unit includes an electromagnetic actuator for driving the drive pin, etc., but since it has the same configuration as the conventional one, illustration and detailed description thereof are omitted.

As shown in FIGS. 1 and 2, the main plate 1 rotatably supports a leading blade main arm 61 in a blade chamber, which will be described later. 13. The base plate 1 rotatably supports a trailing blade main arm 71 in a blade chamber, which will be described later, and has a pivot shaft 14 serving as the center of rotation of the trailing blade main arm 71 . Through holes 11 and 12 are formed in the base plate 1 along the locus of movement of the driving pin 81 for the leading blade and the driving pin 82 for the trailing blade. The through-holes 11 and 12 are elongated holes extending in arcuate shapes about the rotation shafts 13 and 14 respectively, and penetrate the base plate 1 . A front blade drive pin 81 and a rear blade drive pin 82 are inserted through the through holes 11 and 12 .

<Cover plate 2>
The cover plate 2 is attached to the base plate 1 at a position facing the base plate 1 with a predetermined gap therebetween. The cover plate 2 is arranged at a position close to an imaging element (not shown) in an imaging apparatus equipped with a focal plane shutter. However, the orientation of the base plate 1 and the cover plate 2 with respect to the position of the imaging element can be changed arbitrarily. In the blade chamber between the base plate 1 and the cover plate 2, there are provided an intermediate plate 3, a front blade 4, a rear blade 5, a front blade main arm 61, a front blade secondary arm 62, a rear blade main arm 71, and a rear blade. A follower arm 72 and the like are arranged. A space formed by the base plate 1 and the cover plate 2 or a space formed by the base plate 1, the cover plate 2 and the intermediate plate 3 may be referred to as a "blade chamber". The cover plate 2 has an opening 2a formed at a position facing the opening 1a of the base plate 1. As shown in FIG. Although the opening 2a has a rectangular shape similar to that of the opening 1a, it may not be completely rectangular, and may have any shape other than a rectangular shape.

<Intermediate plate 3>
The intermediate plate 3 is arranged between the base plate 1 and the cover plate 2 . A trailing blade 5 , a trailing blade main arm 71 , and a trailing blade secondary arm 72 are housed between the intermediate plate 3 and the base plate 1 . Between the intermediate plate 3 and the cover plate 2, the leading blade 4, leading blade main arm 61, and leading blade secondary arm 62 are housed. The intermediate plate 3 has a rectangular opening 3 a at a position facing the opening 1 a of the base plate 1 and the opening 2 a of the cover plate 2 . Like the openings 1a and 2a, the opening 3a of the intermediate plate 3 may also have any shape other than rectangular.

<Front blade 4>
The front blade 4 is arranged in the blade chamber between the cover plate 2 and the intermediate plate 3 as described above. The front blade 4 is composed of a plurality of plate-like members, and is connected to the front blade main arm 61 and the front blade secondary arm 62 by a connecting tool such as a rivet. The front blade 4 is driven by the front blade drive pin 81 via the front blade main arm 61, and is in a state of covering and opening the exposure opening formed by the openings 1a, 2a and 3a (open/closed state). switch. The front blade 4 and the rear blade 5 are each made of a material such as metal such as aluminum, carbon fiber, or resin, but are not limited to these materials.

<Rear blade 5>
The rear blade 5 is arranged in the blade chamber between the base plate 1 and the intermediate plate 3 as described above. Like the front blade 4, the rear blade 5 is composed of a plurality of plate-like members, and is connected to the rear blade main arm 71 and the rear blade secondary arm 72 by a connecting tool such as a rivet. The trailing blade 5 is driven by a trailing blade drive pin 82 via a trailing blade main arm 71 to cover and open the exposure opening formed by the openings 1a, 2a and 3a (open/closed state). switch.

<Main arm 61 for front blade>
The front blade main arm 61 is arranged between the front blade drive pin 81 and the front blade 4 and is connected to the front blade 4 by a connector. The front blade main arm 61 transmits the driving force generated by the driving portion to the front blade 4 via the front blade drive pin 81 . The leading blade main arm 61 rotates about the rotating shaft 13, with the rotating shaft 13 of the base plate 1 inserted through the rotating shaft hole 61a.

The front blade main arm 61 includes a main body portion 61d and an extension portion 61b. The main body portion 61d has the same shape as a main body portion 361d in a comparative example described later, which does not have an extended portion 61b, and the extended portion 61b has a shape protruding from the main body portion 61d. The extended portion 61b is formed to extend in an arc shape along the region where the through hole 11 is formed. The front blade main arm 61 is a plate-like member. As shown in FIGS. 1 and 2, the extended portion 61b covers the entire through hole 11 when the leading blade 4 covers the opening. On the other hand, when the leading blade 4 opens the opening (retracted from the opening), the extended portion 61b is positioned away from the through hole 11, but is formed so as not to protrude from the base plate 1 in plan view. ing. As shown in the cross-sectional view of FIG. 4, the extended portion 61b has a groove-shaped recessed portion 61c formed on the surface on the through hole 11 side. An adhesive that traps dust such as abrasion powder is placed in the concave portion 61c. The main arm 61 for leading blades, the main arm 71 for trailing blades, or a combination thereof is a structural example of the "arm" of the present invention.

<Main Arm 71 for Rear Blade>
The trailing blade main arm 71 is configured to drive the trailing blade 5 and has the same configuration as the leading blade main arm 61 . The trailing blade main arm 71 is arranged between the trailing blade drive pin 82 and the trailing blade 5 and is connected to the trailing blade 5 by a connector. The trailing blade main arm 71 transmits the driving force generated by the driving portion to the trailing blade 5 via the trailing blade drive pin 82 . The main arm 71 for the trailing blade rotates around the rotation shaft 14, with the rotation shaft 14 of the base plate 1 inserted through the rotation shaft hole 71a.

The trailing blade main arm 71 includes a body portion (reference numerals omitted) and an extension portion 71b. The extended portion 71b has a groove-shaped concave portion 71c formed on the surface on the through hole 12 side. The trailing blade main arm 71 has the same configuration as the leading blade main arm 61 shown in FIG. 3, so a detailed description thereof will be omitted.

<Comparison example of main arm>
FIG. 5 shows a configuration example of a main arm 361 that does not have an extension portion 61b and has only a main body portion 361d. The main arm 361 has a body portion 361d and a rotary shaft hole 361a. Compared to the main arm 361, the main arm 61 for the leading blade and the main arm 71 for the trailing blade are different in that they have an extended portion 61b as a characteristic portion.

<Leading blade trailing arm 62 and trailing blade trailing arm 72>
The leading blade follower arm 62 is connected to the leading blade 4 as described above. The leading blade follower arm 62 is rotatably connected to the main plate 1 . The leading blade follower arm 62 is not directly supplied with a driving force from the driving section, and operates in accordance with the operation of the leading blade main arm 61 . The trailing blade follower arm 72 is connected to the trailing blade 5 as described above. The trailing blade follower arm 72 is rotatably connected to the main plate 1 . The trailing blade follower arm 72 is not directly provided with a driving force from the driving section, and operates in accordance with the operation of the trailing blade main arm 71 .

<Front Blade Drive Pin 81 and Rear Blade Drive Pin 82>
The leading blade driving pin 81 and the trailing blade driving pin 82 are each connected to a driving portion including an electromagnetic actuator. The leading blade drive pin 81 and the trailing blade drive pin 82 are made of metal, for example. The drive section is operated by electric power supplied from the outside, and transmits power to the leading blade drive pin 81 and the trailing blade drive pin 82 . The leading blade drive pin 81 and the trailing blade drive pin 82 are connected to the leading blade through the leading blade main arm 61 and the leading blade secondary arm 62, and the trailing blade main arm 71 and the trailing blade secondary arm 72, respectively. 4 and the rear blade 5 are driven to adjust the opening/closing state of the opening 1a. The traveling operation of the leading blade 4 and the trailing blade 5 is the same as in the conventional configuration. The leading blade drive pin 81, the trailing blade drive pin 82, or a combination thereof is a configuration example of the "drive pin" of the present invention.

The drive section includes, for example, a permanent magnet, a yoke, a coil, a coil spring, etc. in addition to the leading blade driving pin 81 and the trailing blade driving pin 82, and is operated by given electric power. The drive includes conventionally known electromagnetic actuators or motors.

An imaging apparatus including the focal plane shutter of the present embodiment includes an imaging element mounted on a substrate on the opposite side of the focal plane shutter from the imaging target. The imaging element is, for example, a CMOS sensor or a photoelectric conversion element such as a CCD. The imaging device is arranged at a position overlapping these openings 1a, 2a and 3a in a plan view so as to receive light passing through the openings 1a, 2a and 3a (exposure openings).

<Modification 1>
The leading blade main arm 61 and the trailing blade main arm 71 in the focal plane shutter of this embodiment have the configuration in which the concave portion 61c is formed in the extended portion 61b. good. FIG. 6 is a diagram showing a configuration example of the front blade main arm 161 in such a modification. The leading blade main arm 161 is plate-shaped and has an extended portion 161b protruding from a main body portion 161d. The leading blade main arm 161 has a rotary shaft hole 161a. No concave portion is formed in the extended portion 161b. Further, the extended portion 161b is formed with a length not covering the entire through-hole 11 but a length covering a region of 1/2 or more of the through-hole 11 . The length of the extended portion 161b is not necessarily limited to this length, and a configuration that covers the entire through-hole 11 is more effective in suppressing abrasion powder from entering the blade chamber and the like. target. Also in the case of this modification, the pressure-sensitive adhesive may be arranged on the surface of the extended portion 161b on the through hole 11 side at a height that does not contact the surface of the base plate 1 on the blade chamber side. Furthermore, in the trailing blade main arm whose description is omitted, an adhesive may be placed on the surface on the through hole 12 side in the same manner as the extended portion 161 b of the leading blade main arm 161 . By arranging the adhesive in this way, it is possible to more reliably suppress the intrusion of abrasion powder into the blade chambers and the like.

<Modification 2>
In the focal plane shutter of the present embodiment, an adhesive for capturing dust such as abrasion powder is placed in the concave portion 61c. Alternatively, instead of the adhesive, a magnet sheet for capturing metal may be placed. good. The magnet sheet is formed of a permanent magnet formed in a plate shape (sheet shape). With a configuration using such a magnet sheet, metal powder can be captured. Compared to a configuration using an adhesive, this is preferable in that there is no fear that the member itself that captures abrasion powder will scatter.

<Characteristics of the Focal Plane Shutter of the Present Embodiment>
In the focal plane shutter of this embodiment, as described above, when the front blade 4 covers the openings 1a, 2a, and 3a (the state shown in FIG. 1), the entire through hole 11 is covered by the front blade main arm. 61 is covered by an extended portion 61b. As a result, the focal plane shutter of the present embodiment prevents abrasion powder generated outside the blade chamber from passing through the through holes 11 and entering the blade chamber, or from passing through the blade chamber and adhering to the imaging device. can do. Furthermore, it is possible to suppress imperfections in the operation of the blades caused by abrasion powder and deterioration in image quality of captured images.

6, when the front blade 4 covers the openings 1a, 2a, and 3a (the state shown in FIG. 1), half or more of the through hole 11 is used for the front blade. Even if the expanded portion 61b of the main arm 61 covers the main arm 61, a certain effect can be obtained in suppressing abrasion powder from entering the blade chamber or adhering to the imaging device. The same applies to the extended portions 61b and 71b described with reference to FIGS. 1 to 4. FIG. Even in that case, the recesses 61c, 71c are formed in the respective extensions 61b, 71b.

Further, instead of the leading blade main arm 61, the trailing blade main arm 71 may be configured as described above. Moreover, it is more effective if both the leading blade main arm 61 and the trailing blade main arm 71 are configured as described above. In the following description, the configuration for the leading blade 4 will be mainly described, but the configuration may be replaced with the configuration for the trailing blade 5, or the leading blade 4 and the trailing blade 5 may have similar features. may be adopted.

In addition, since the blades operate at a higher speed during running than when they are returned to the pre-running state, scattering of abrasion powder and the like is particularly likely to occur at the timing when running is completed. Therefore, when adopting a configuration having no extended portion, if a configuration having an extended portion on the side of the rear blade 5 where the through-hole is opened when the running is completed, the extended portion is provided on the side of the front blade 4. In some cases, it is more effective than the case of adopting a configuration with

Further, in the focal plane shutter of this embodiment, when the front blade 4 opens the openings 1a, 2a, and 3a (the state shown in FIG. 2), the extended portion 61b does not protrude from the base plate 1 in plan view. and As a result, it is possible to prevent the extended portion 61b from protruding from the area of the base plate 1 of the focal plane shutter and coming into contact with other components and being damaged.

Further, in the focal plane shutter of this embodiment, the extended portion 61b protrudes from the main body portion 61d of the main arm 61 for the front blade and extends in an arc shape along the area where the through hole 11 is formed. As a result, the expanded portion 61b can have an effective shape to cover the through hole 11, so that it is possible to more effectively suppress abrasion powder from entering the blade chamber and the vicinity of the imaging element.

Further, in the focal plane shutter of the present embodiment, since the groove-shaped concave portion 61c is formed in the extended portion 61b, the abrasion powder is easily confined in the concave portion 61c, and the abrasion powder enters the blade chamber and the vicinity of the imaging element. can be suppressed more effectively.

Further, in the focal plane shutter of the present embodiment, the adhesive is placed in the concave portion 61c formed on the through hole 11 side of the extended portion 61b so that abrasion powder can be captured by the adhesive. It is possible to more effectively suppress the abrasion powder adhering to 61b from scattering again due to repeated travel of the blade. As a result, it is possible to more effectively suppress the abrasion powder from entering the vicinity of the blade chamber and the imaging element.

In addition, as described in the modified example of FIG. 6, the adhesive may be arranged on the through-hole 11 side of the extended portion 61b without providing the concave portion. Even if such a configuration is adopted, it is possible to obtain a certain effect in suppressing re-scattering of the abrasion powder adhering to the expanded portion 61b due to repeated travel of the blades.

<2. Embodiment 2>
Next, Embodiment 2 of the present invention will be specifically described with reference to FIGS. 7 to 10. FIG. The present embodiment differs from the first embodiment in that the leading blade main arm 61 and the trailing blade main arm 71 are replaced with a leading blade main arm 261 and a trailing blade main arm 271. The configuration is common. In the following, the points of difference when compared with the first embodiment will be mainly described, and the description of the points common to the first embodiment will be omitted.

7 and 8 are plan views of the focal plane shutter of this embodiment, FIG. 7 showing the state before the blades travel, and FIG. 8 showing the state after the blades travel. FIG. 9 is an enlarged plan view of the leading blade main arm 261. FIG. FIG. 10 is a cross-sectional view of the extended portion 261b of the main arm 261 for the leading blade.

<Main arm 261 for front blade>
The front blade main arm 261 is arranged between the front blade driving pin 81 and the front blade 4 and is connected to the front blade 4 by a connector. The front blade main arm 261 transmits the driving force generated by the driving portion to the front blade 4 via the front blade drive pin 81 . The leading blade main arm 261 rotates about the rotating shaft 13, with the rotating shaft 13 of the base plate 1 inserted through the rotating shaft hole 261a.

The front blade main arm 261 includes a main body portion 261d and an extension portion 261b. The extended portion 261b has a shape protruding from the body portion 261d. The extended portion 261b is formed to extend in an arc shape along the region where the through hole 11 is formed. As shown in FIGS. 1 and 2, the extended portion 261b covers the entire through hole 11 when the front blade 4 covers the opening. On the other hand, when the front blade 4 opens the opening (retracted from the opening), the extended portion 261b is located away from the through hole 11, but is formed so as not to protrude from the base plate 1 in plan view. ing.

Unlike the extension portion 61b of the first embodiment, the extension portion 261b has a wall portion 261c instead of the recess portion 61c. As shown in the cross-sectional view of FIG. 10, the extended portion 261b has a wall portion 261c formed to extend toward the through hole 11 side. The wall portion 261c is formed by bending portions of the extended portion 261b corresponding to both sides with respect to the extending direction of the through hole 11 in the front blade main arm 261 formed in a plate shape. The wall portion 261c is formed to have a height that does not make contact with the base plate 1 . An adhesive is applied to the portion of the extended portion 261b surrounded by the wall portion 261c.

<Main Arm 271 for Rear Blade>
The trailing blade main arm 271 includes a body portion (reference numerals omitted) and an extension portion 271b. The extended portion 271b has a wall portion 271c on the through hole 11 side. The main arm 271 for the trailing blade rotates around the rotation shaft 14, with the rotation shaft 14 of the base plate 1 inserted through the rotation shaft hole 271a. The trailing blade main arm 271 has the same configuration as the leading blade main arm 261 shown in FIGS. 9 and 10, so a detailed description thereof will be omitted.

<Modification>
In the focal plane shutter of this embodiment, the adhesive is placed in the extended portion 261b surrounded by the wall portion 261c, but instead of the adhesive, a magnet sheet that captures metal may be placed. . The magnet sheet is formed of a permanent magnet formed in a plate shape (sheet shape). With a configuration using such a magnet sheet, metal powder can be trapped. Compared to a configuration using an adhesive, this is preferable in that there is no fear that the member itself that captures abrasion powder will scatter.

<Characteristics of the Focal Plane Shutter of the Present Embodiment>
As described above, the focal plane shutter of this embodiment is configured such that the wall portion 261c extending toward the through hole 11 is formed on the surface of the extended portion 261b on the through hole 11 side. Therefore, even if abrasion powder adhering to the expanded portion 261b tends to scatter when the blades are repeatedly driven, the wall portion can suppress the scatter. As a result, it is possible to effectively prevent abrasion powder from entering the vicinity of the blade chamber and the imaging element. Since the wall portion 261c can be configured to have a height higher than that of the recessed portion 61c, it is preferable in terms of suppressing scattering of abrasion powder. However, in terms of reducing the thickness of the focal plane shutter, the configuration having the concave portion 61c of the first embodiment may be preferable.

Further, in the focal plane shutter of the present embodiment, the wall portions 261c are formed at the edges of the extended portion 261b along both sides in the direction in which the through hole 11 extends. Such a configuration is preferable because the wall portion 261c can be formed relatively easily.

Note that the wall portion 261c may be formed on one edge of the extension portion 261b instead of on both edges. Even if such a configuration is adopted, a certain effect can be obtained in terms of suppressing the scattering of abrasion powder.

Also, the wall portion 261c may be formed at a position near the edge of the extended portion 261b instead of at the edge. Even if such a configuration is adopted, a certain effect can be obtained in terms of suppressing the scattering of abrasion powder.

In addition, the wall portion 261c is formed not only along both sides of the extension portion 261b in the direction in which the through hole 11 extends, but also so that the wall portion 261c continuously surrounds a predetermined region of the extension portion 261b from all sides. may be formed. In such a configuration, the wall portion 261c that surrounds the through hole 11 can more effectively prevent abrasion powder adhering to the extended portion 261b from entering the blade chamber and the vicinity of the imaging device. Further, even if the extended portion 261b provided with the wall portion 261c is configured to cover more than 1/2 of the through hole 11, it is possible to suppress abrasion powder from entering the blade chamber or adhering to the imaging element. A certain effect can be obtained.

<3. Supplementary matter>
The specific description of the embodiment of the present invention has been given above. The above description is merely one embodiment, and the scope of the present invention is not limited to this one embodiment, but is interpreted broadly to the extent that a person skilled in the art can comprehend.

Although the extended portion of the main arm of the focal plane shutter of each of the above embodiments has a shape extending from the main body along the direction in which the through hole extends, the shape is not necessarily limited to such a shape. A shape that is enlarged all over may be adopted. However, when adopting a shape in which the extended portion largely protrudes from the main body as a whole, the main arm may become larger and heavier than the shape of the embodiment.

Also, in the embodiment, a configuration in which the main arm has an extension portion has been described, but depending on the arrangement of the main arm and the follower arm, a configuration in which the follower arm has an extension portion may be employed.

Further, in the embodiment, the front blade 4 and the rear blade 5 provided in the focal plane shutter have been described as having a plurality of blade members, respectively. It may be a configuration having.

Further, although the focal plane shutter including the front blade 4 and the rear blade 5 has been described in the embodiment, a configuration including only one of the front blade 4 and the rear blade 5 may be adopted. In that case, in the focal plane shutter of the embodiment, a configuration example having the intermediate plate 3 has been described, but a configuration without the intermediate plate 3 may be adopted.

INDUSTRIAL APPLICABILITY The present invention is suitably applied as a focal plane shutter of an imaging device such as a digital camera.

DESCRIPTION OF SYMBOLS 1... Base plate 1a, 2a, 3a... Opening part 11, 12... Through hole 13, 14... Rotating shaft 2... Cover plate 3... Intermediate plate 4... Front blade 5... Rear blade 61, 161, 261... Main blade for front blade Arms 61a, 161a, 261a Rotating shaft hole 61b, 161b, 261b Extended portion 61c Recessed portion 261c Wall portion 61d, 261d Body portion 62 Leading blade follower arms 71, 271 Rearing blade main arm 71a , 271a... Rotating shaft hole 71b, 271b... Extended part 71c... Recessed part 271c... Wall part 72... Rear blade follower arm 81... Leading blade drive pin 82... Rear blade drive pin 361... Main arm 361a... Turn Driving shaft hole 361d...Main body

Claims (13)

a base plate having an opening, a through hole, and a pivot shaft;
a cover plate arranged at a position facing the base plate with a predetermined interval;
a blade chamber formed between the base plate and the cover plate;
a blade disposed in the blade chamber and switching between a state of covering the opening and a state of opening the opening;
an arm that is arranged in the blade chamber, rotates about the rotation shaft, and is connected to the blade;
a drive pin inserted through the through-hole, moving in the through-hole forming region, and connected to the arm;
the arm has an extended portion formed to cover 1/2 or more of the through hole when the blade covers the opening;
The extension portion protrudes from the main body portion of the arm and is formed to extend in an arc shape along the region where the through hole is formed.
Focal plane shutter. The extension portion is formed so as not to protrude from the base plate in a plan view when the blade opens the opening.
A focal plane shutter according to claim 1. The extension portion is formed to cover the entire through-hole when the blade covers the opening.
3. A focal plane shutter according to claim 1 or 2. An adhesive is placed on the surface of the extended portion on the through-hole side,
A focal plane shutter according to any one of claims 1 to 3 . A permanent magnet is arranged on a surface of the extended portion on the through hole side,
A focal plane shutter according to any one of claims 1 to 3 . The extended portion has a concave portion formed on a surface on the through hole side,
A focal plane shutter according to any one of claims 1 to 3 . An adhesive is placed in the recess,
7. A focal plane shutter according to claim 6 . A permanent magnet is arranged in the recess,
7. A focal plane shutter according to claim 6 . The extended portion has a wall portion extending toward the through hole on a surface on the through hole side,
A focal plane shutter according to any one of claims 1 to 5 . the wall is formed at or near the edge of the extension along the direction in which the through hole extends;
10. A focal plane shutter according to claim 9 . the walls are formed on both edges of the extension;
11. A focal plane shutter according to claim 10 . The wall portion is formed to surround part or all of a surface of the extension portion on the through hole side,
11. A focal plane shutter according to claim 10 . An imaging apparatus comprising the focal plane shutter according to any one of claims 1 to 12 .

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