JP2017194642A - Shutter device and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress exposure unevenness.SOLUTION: A shutter device comprises: a base plate that has an opening; a light shield member that moves from a first location on an outer side of the opening to a second location different from the first location; a movement member that rotates centering around a first axis to move the light shield member between the first location and the second location; and a rotary member that has an engagement part engaging with the movement member, and rotates centering around a second axis due to driving force from a drive unit. A ratio of a first length between the first axis and the engagement part and a second length between the second axis in a direction connecting the first axis to the engagement part and the engagement part varies according to rotation of the rotary member.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a shutter device and an imaging device.

A shutter device including a front curtain light shielding blade and a rear curtain light shielding blade is known (see, for example, Patent Document 1).
In an electronic camera provided with a conventional shutter device, exposure unevenness may occur.

JP 2008-164804 A

(1) The shutter device according to claim 1 is centered on a first axis, a substrate having an opening, a light shielding member that moves from a first position outside the opening to a second position different from the first position, and A moving member that rotates the light shielding member between the first position and the second position, and an engaging portion that engages with the moving member. A rotating member that rotates about a shaft, and a first length between the first shaft and the engaging portion, and the second shaft in a direction connecting the first shaft and the engaging portion. The ratio of the second length between the engagement portion and the engagement portion is changed by the rotation of the rotation member.
(2) According to a seventh aspect of the present invention, in the shutter device according to the seventh aspect, the substrate having an opening, the first light-shielding member that moves from the first position to the second position, and the third light-shielding member from the third position after the movement of the first light-shielding member. A second light-shielding member that moves to four positions; and a drive mechanism that drives one of the first and second light-shielding members. The drive mechanism is centered on the first axis by a drive force from a drive unit. A moving member that rotates about the second axis different from the first axis by the rotation of the rotating member, and moves the light shielding member. And a first length between the second shaft and the engaging portion, and the first shaft and the engaging portion in a direction connecting the second shaft and the engaging portion. The ratio with the second length is changed by the rotation of the rotating member.
(3) An imaging apparatus according to an eleventh aspect includes the shutter apparatus according to any one of the first to tenth aspects, and an imaging element that captures an image of a light beam that has passed through the opening.

It is a figure explaining the principal part structure of a digital camera. It is a figure which shows the internal structure of a shutter apparatus. It is a figure which shows the internal structure of a shutter apparatus. It is a figure which shows the internal structure of a shutter apparatus. It is a component diagram about a part of each member which comprises a shutter apparatus. It is a figure which shows typically the positional relationship of the position of an opening, the imaging surface of an image pick-up element, and the slit formation end of the front curtain light-shielding blade and the rear curtain light-shielding blade that are retracted to the first retracted position. . It is a figure explaining the drive torque transmitted to a front-curtain drive arm. It is a figure explaining the drive torque transmitted to a front-curtain drive arm. It is a figure explaining the drive torque transmitted to a front-curtain drive arm. It is a graph showing the time-dependent change of the drive torque transmitted to a front-curtain drive arm and a rear-curtain drive arm. It is a graph which shows the running characteristic of a front curtain light-shielding blade and a rear curtain light-shielding blade. It is a figure which shows the internal structure of a shutter apparatus. It is a figure which shows the internal structure of a shutter apparatus. It is a figure which shows the internal structure of a shutter apparatus. It is a figure explaining the drive torque transmitted to a front-curtain drive arm. It is a figure explaining the drive torque transmitted to a front-curtain drive arm. It is a figure explaining the drive torque transmitted to a front-curtain drive arm. It is the graph showing the time-dependent change of the drive torque transmitted to the front-curtain drive arm and the rear-curtain drive arm about the modification. It is a graph which shows the running characteristic of a front curtain light-shielding blade and a rear curtain light-shielding blade about a modification.

--- First embodiment ---
An imaging apparatus including the shutter device according to the first embodiment will be described with reference to the drawings.
FIG. 1 is a diagram for explaining a main configuration of a digital camera 1 that is an imaging apparatus according to the present embodiment. As shown in FIG. 1, the digital camera 1 is a so-called mirrorless camera including a camera body 20 and a lens barrel 10 that can be attached to and detached from the camera body 20 via a lens mount 9. The digital camera 1 may be a single lens reflex camera instead of a mirrorless camera.

  The lens barrel 10 includes an imaging optical system 11 and a diaphragm 12. The imaging optical system 11 is an optical system for forming a subject image on a predetermined imaging surface, and is composed of a plurality of lenses including a focus adjustment lens. The focus adjustment lens moves forward and backward in the direction of the optical axis L by the operation of a lens driving motor (not shown). In FIG. 1, for convenience of illustration, the imaging optical system 11 is schematically shown as a single lens. The diaphragm 12 defines the F value of the imaging optical system 11.

  Inside the camera body 20, a shutter device 21, an image sensor 22, and a control device 26 are provided. On the back surface of the camera body 20, a back monitor 30 constituted by a display device such as a liquid crystal display is provided. The camera body 20 is provided with an operation unit 40.

  The image pickup device 22 is an image pickup device such as a CMOS having a number of pixels arranged in a matrix, and is arranged so that the image pickup surface is positioned on the image formation surface of the image formation optical system 11. The image sensor 22 receives subject light through the opening of the shutter device 21. That is, the image sensor 22 captures the subject image formed on the imaging surface by the imaging optical system 11 and outputs an image signal to the control device 26. Although not shown in FIG. 1, various optical filters such as an infrared cut filter are provided on the imaging surface of the imaging element 22. A plurality of pixels constituting the image sensor 22 are two-dimensionally arranged in a pixel row direction (X-axis direction in FIG. 2 described later) and a pixel column direction orthogonal to the pixel row direction (Y-axis direction in FIG. 2 described later). The pixel reset and the readout of the imaging signal are performed at different timings for each pixel row at different positions in the pixel column direction.

  The shutter device 21 is provided on the front surface (subject side) of the image sensor 22. The shutter device 21 is driven from the subject toward the image sensor 22 by being driven by a front curtain actuator and a rear curtain actuator (not shown) according to a drive signal from a power control unit (not shown) of the control device 26 described later. This is a so-called focal plane shutter that shields and exposes an incident light beam. The details of the shutter device 21 will be described later.

The control device 26 is composed of a microprocessor and its peripheral circuits and the like, and by reading and executing a control program stored in advance in a storage medium (not shown) (for example, a flash memory), each part of the digital camera 1 is controlled. Control. The control device 26 performs various image processing on the imaging signal output from the imaging element 22 to generate image data of the subject image, and generates the image data on a portable storage medium (not shown) (for example, a memory card). Record image data. The control device 26 controls the operation of the shutter device 21 and the image sensor 22 as will be described later. The control device 26 includes a power control unit (not shown) for controlling the operation of the shutter device 21 as a function.
Note that the control device 26 may be configured by an electronic circuit having a function equivalent to that of the control program.

  The operation unit 40 includes various switches provided corresponding to various operation members operated by the user, and outputs an operation signal corresponding to the operation of the operation member to the control device 26. The operation member determines, for example, a release button, a menu button for displaying a menu screen on the rear monitor 30, a cross key operated when selecting and operating various settings, a setting selected by the cross key, and the like. And a mode switching button for switching the operation of the digital camera 1 between the shooting mode and the playback mode.

Hereinafter, details of the shutter device 21 of the present embodiment will be described.
2 to 4 are diagrams showing the internal structure of the shutter device 21 as viewed from the image sensor 22 side, that is, from the back side of the digital camera 1. For convenience of explanation, a coordinate system consisting of an X axis and a Y axis is set as shown. FIG. 2 is a diagram showing the state of the shutter device 21 before an instruction to start photographing by operating the release button. Both the first-curtain light shielding blade 220 and the rear-curtain light shielding blade 250, which will be described later, are provided on the shutter opening ( A state of being retracted to a first retracted position (first position) 201 above (opening) 215 is shown. That is, the shutter device 21 of the present embodiment is a normally open type shutter device that opens the opening 215 in a shooting preparation state before starting shooting.
FIG. 3 shows the shutter device 21 after the front button shading blade 220 starts to move downward in the figure so as to cross the opening 215 after the user operates the release button and is instructed to start photographing. It is a figure which shows a state, and shows the state before the trailing curtain light-shielding blade 250 starts moving. 4 shows a state immediately before the front curtain light-shielding blade 220 moves further downward from the state shown in FIG. 3 and completes the retreat to the second retreat position (second position) 202 below the opening 215. It is a figure shown, and the state before the trailing curtain light-shielding blade 250 starts a movement is shown.
FIG. 5 is a component diagram of a part of each member constituting the shutter device 21. FIG. 5A is a component diagram of the front curtain light shielding blade 220. FIG. 5B is a component diagram of the front curtain drive arm 221 and the front curtain driven arm 231. FIG. 5C is a component diagram of the first curtain drive second lever 320. FIG. 5D is a component diagram of the first curtain drive first lever 310. 5A to 5D, the parts where the components are connected to each other or the parts arranged on the same axis are connected by a one-dot chain line.

  As shown in FIGS. 3 and 5, the shutter device 21 includes a shutter substrate (substrate) 210, a front curtain light shielding blade 220, a rear curtain light shielding blade 250, a front curtain drive arm 221, a front curtain driven arm 231, Front curtain drive first lever 310, front curtain drive second lever 320, rear curtain drive arm 251, rear curtain driven arm 261, rear curtain drive lever 330, front curtain actuator (not shown), and not shown. And a rear curtain actuator. In the present embodiment, the front curtain actuator and the rear curtain actuator have, for example, a spring as a drive source. The front curtain drive arm 221, the front curtain driven arm 231, the front curtain drive first lever 310, and the front curtain drive second lever 320 are included in a front curtain drive mechanism 203 described later. The rear curtain drive arm 251, the rear curtain follower arm 261, and the rear curtain drive lever 330 are included in a rear curtain drive mechanism 204 described later.

  The substrate 210 is fixed inside the camera body 20 and has an opening 215 for exposing the image sensor 22 with a subject light beam. The opening 215 is formed in a rectangular shape surrounded by two long sides extending along the X axis and two short sides extending along the Y axis. In the following description, it is assumed that the Y-axis side of the opening 215 is the upper end 215U, the Y-axis + side is the lower end 215B, and the length in the Y-axis direction between the upper end 215U and the lower end 215B is L0.

--- First curtain drive mechanism 203 ---
The front curtain drive mechanism 203 will be described.
For example, as well shown in FIGS. 3 and 5, the front curtain light shielding blade 220 is a light shielding member extending along the X axis, and the right end portion in the drawing is the front curtain driving arm 221 and the front curtain driven arm 231. Is pivotally supported. In the present embodiment, the leading blade shading blade 220 is constituted by a single blade.
The front curtain drive arm 221 has a substrate side connecting portion 222 at one end, and is pivotally supported on the front surface (subject side) of the substrate 210 by the substrate side connecting portion 222. The front curtain driven arm 231 has a substrate side connecting portion 232 at one end, and the substrate side connecting portion 232 is pivotally supported on the front surface (subject side) of the substrate 210 above the front curtain driving arm 221 in the drawing. Has been. The front curtain drive arm 221 has a light shielding member side connecting portion 223 at the other end, and the front curtain light shielding blade 220 is rotatably connected to the light shielding member side connecting portion 223 by a caulking pin. The front curtain follower arm 231 has a light shielding member side connecting portion 233 at the other end, and the front curtain light shielding blade 220 is rotatably connected by a caulking pin at the light shielding member side connecting portion 233. The front curtain drive arm 221 and the front curtain follower arm 231 constitute a known parallel link mechanism that moves the front curtain light-shielding blade 220.
The front curtain drive arm 221 and the front curtain driven arm 231 are provided below the rear curtain drive arm 251 and the rear curtain driven arm 261 in the figure. Specifically, the substrate side connecting portion 222 of the front curtain driving arm 221 and the substrate side connecting portion 232 of the front curtain driven arm 231 are a substrate side connecting portion 252 (to be described later) of the rear curtain driving arm 251 and a rear curtain driven arm. It is coupled to the substrate 210 below the substrate side connecting portion 262 of 261 described later.

  The front-curtain drive arm 221 is provided with a hole 224, and the front-curtain second drive pin 281 penetrating through the long hole 240 of the substrate 210 is inserted into the hole 224 from the front side of the page, that is, from the back side of the digital camera 1. . The front curtain second drive pin 281 is attached to the front curtain drive second lever 320.

The front curtain drive second lever 320 has a substrate side connecting portion 321 at one end, and a front curtain second drive pin 281 is attached to the other end. The front curtain drive second lever 320 is pivotally supported on the back surface (image sensor 22 side) of the substrate 210 at the substrate-side connecting portion 321 so as to be rotatable. It should be noted that the pivot support position of the board side connection portion 321 is the same as the pivot support position of the board side connection section 222 of the front curtain drive arm 221.
That is, the front curtain drive second lever 320 is pivotally supported coaxially with the front curtain drive arm 221 with respect to the substrate 210, and a front curtain second drive pin 281 attached to the other end of the front curtain drive arm 221. Since it is inserted into the hole 224, it rotates integrally with the front curtain drive arm 221 around the board side coupling portions 222 and 321.
The front curtain drive second lever 320 is provided with an elongated hole 322 extending from one end side to the other end side. The front curtain first drive pin 312 is inserted into the elongated hole 322. The front curtain first drive pin 312 is attached to the front curtain drive first lever 310.

  The first curtain drive first lever 310 has a substrate side connecting portion 311 at one end, and is pivotally supported by the substrate side connecting portion 311 on the back surface of the substrate 210 (on the image sensor 22 side) so as to be rotatable. The first curtain first drive pin 312 is attached to the other end of the first curtain drive first lever 310. The substrate side connecting portion 311 of the first curtain drive first lever 310 is coupled to the substrate 210 at an obliquely lower right side of the substrate side connecting portion 222 of the front curtain drive arm 221 in the drawing. That is, the position of the board side connecting portion 311 that is the rotation center of the front curtain driving first lever 310 is the position of the board side connecting portions 222 and 321 that is the rotation center of the front curtain driving arm 221 and the front curtain driving second lever 320. And different. The front curtain first drive pin 312 is located on the left side of the substrate side connecting portion 222 of the front curtain drive arm 221 in the drawing.

  The first curtain drive first lever 310 is driven by a front curtain actuator (not shown). When the front curtain drive first lever 310 is pivoted about the board side connecting portion 311 by the front curtain actuator, the front curtain first drive pin 312 and the elongated hole 322 of the front curtain drive second lever 320 are engaged. As a result, the front curtain drive second lever 320 is rotated about the board-side connecting portion 321. As a result, the front curtain drive arm 221 and the front curtain follower arm 231 that rotate together with the front curtain drive second lever 320 are rotated about the board side coupling part 222 and the board side coupling part 232. .

  When the front curtain drive arm 221 is driven to rotate about the board-side coupling portion 222, as described above, the well-known parallel structure constituted by the front curtain drive arm 221, the front curtain driven arm 231, and the front curtain light shielding blade 220. The front curtain light-shielding blade 220 is driven by the link mechanism, and the opening 215 of the substrate 210 is moved in the Y-axis direction. In the present embodiment, the front curtain light-shielding blade 220 has a first retraction position 201 that is a first position outside the opening 215 and a second retraction that is a second position outside the opening 215 that faces the first position. It can move between positions 202 (FIGS. 2 and 4). The first retraction position 201 and the second retraction position 202 are opposed to each other with the opening 215 interposed therebetween. The first retraction position 201 is provided above the opening 215 in the drawing, and the second retraction position 202 is the opening 215. Provided in the lower part of the figure. In FIG. 2, the front curtain light blocking blade 220 has moved to the first retreat position 201. As described above, FIG. 4 shows a state immediately before the front curtain light-shielding blade 220 is completely moved to the second retreat position 202.

  As described above, the front curtain light-shielding blade 220 is composed of a single blade. Upper edge 220U (FIG. 3) which is the side extending along the X axis on the Y axis − side of front curtain light shielding blade 220, and the lower end edge 220B which is the side extending along the X axis on the Y axis + side A length (light-shielding width) L1 along the Y-axis direction (the traveling direction of the front-curtain light-shielding blade 220 and the rear-curtain light-shielding blade 250) with (FIG. 3) is a length L0 along the Y-axis direction of the opening 215. Shorter (smaller). Therefore, the front curtain light shielding blade 220 has a shape that can cover only a part of the opening 215. That is, the front curtain light shielding blade 220 has a shape in which the light shielding range in the traveling direction is shorter than the length of the opening 215 in the traveling direction. Note that the upper end edge 220U of the front curtain light shielding blade 220 is a slit forming end during exposure. That is, the front curtain light-shielding blade 220 has a lower end edge 220B that is one end portion that first enters the opening 215, and an upper end edge 220U that is the other end portion on the opposite side of the lower end edge 220B.

  In the present embodiment, the front curtain light-shielding blade 220 is described as traveling on the front surface (subject side) of the opening 215. However, the front curtain light-shielding blade 220 is also implemented on the rear surface of the opening 215 (imaging element 22 side). It is included in one aspect of the form. Further, the front-curtain light shielding blade 220 is not limited to one configured by a single blade, and may be configured by a plurality of blades so as to cover the entire opening 215 by the plurality of blades. .

--- Rear curtain drive mechanism 204 ---
The rear curtain drive mechanism 204 will be described.
As shown in FIGS. 2 to 4, the rear-curtain light-shielding blade 250 is a light-shielding member composed of a plurality of blades extending along the X axis. 251 and the trailing curtain driven arm 261 are respectively supported on the shaft.
For example, as shown in FIGS. 3 and 4, the rear curtain drive arm 251 has a substrate-side connecting portion 252 at one end, and the substrate-side connecting portion 252 can rotate to the front surface (subject side) of the substrate 210. Is pivotally supported. The rear curtain follower arm 261 has a substrate side connecting portion 262 at one end, and the substrate side connecting portion 262 is pivotally supported on the front surface (subject side) of the substrate 210 below the rear curtain drive arm 251 in the drawing. Has been. The rear curtain drive arm 251 has a light shielding member side connecting portion 253 at the other end, and a plurality of rear curtain light shielding blades 250 are rotatably connected by caulking pins at the light shielding member side connecting portion 253. The rear curtain follower arm 261 has a light shielding member side connecting portion 263 at the other end, and a plurality of rear curtain light shielding blades 250 are rotatably connected by caulking pins at the light shielding member side connecting portion 263. The rear curtain drive arm 251 and the rear curtain follower arm 261 constitute a known parallel link mechanism that moves the rear curtain light shielding blade 250. As described above, the rear-curtain drive arm 251 and the rear-curtain driven arm 261 are provided above the front-curtain drive arm 221 and the front-curtain driven arm 231 in the figure.

  The rear curtain drive arm 251 is provided with a hole 254, and the rear curtain drive pin 282 that passes through the long hole 270 of the substrate 210 is inserted into the hole 254 from the front side of the sheet, that is, from the back side of the digital camera 1. The rear curtain drive pin 282 is attached to the rear curtain drive lever 330.

  The rear curtain drive lever 330 has a substrate side connecting portion 331 at one end thereof, and is pivotally supported by the substrate side connecting portion 331 so as to be rotatable on the back surface of the substrate 210 (on the imaging element 22 side). The pivot support position of the substrate side coupling portion 331 is the same as the pivot support position of the substrate side coupling portion 252 of the trailing curtain drive arm 251. That is, the rear curtain drive lever 330 is pivotally supported on the substrate 210 coaxially with the rear curtain drive arm 251. The rear curtain drive pin 282 is attached to the other end of the rear curtain drive lever 330.

  The rear curtain drive lever 330 is driven by a rear curtain actuator (not shown). When the rear curtain drive lever 330 is rotated about the board-side connecting portion 331 by the rear curtain actuator, the rear curtain drive pin 282 is driven along the elongated hole 270. As a result, the rear-curtain drive arm 251 and the rear-curtain driven arm 261 are rotated around the board-side connecting part 252 and the board-side connecting part 262.

  When the rear curtain drive arm 251 is driven to rotate about the board-side coupling portion 252, as described above, the well-known parallel structure constituted by the rear curtain drive arm 251, the rear curtain driven arm 261, and the rear curtain light shielding blade 250. The rear curtain shading blade 250 is driven by the link mechanism, and the opening 215 of the substrate 210 is moved in the Y-axis direction. In the present embodiment, the rear curtain light shielding blade 250 is movable to the first retreat position 201 and the light shielding position that covers the entire opening 215. As shown in FIGS. 2 to 4, the plurality of blades of the trailing curtain light blocking blade 250 overlap each other at the first retracted position 201. Although not shown, the plurality of blades of the rear curtain light shielding blade 250 are deployed at the light shielding position to shield the entire opening 215 from light.

  Note that the lower edge 250B of the lowermost blade of the plurality of rear curtain light-shielding blades 250 is a slit forming end during exposure. That is, the lowermost blade of the plurality of rear curtain light shielding blades 250 has a lower end edge 250 </ b> B that is one end portion that first enters the opening 215.

  In the present embodiment, the rear curtain light shielding blade 250 is described as traveling on the front surface (subject side) of the opening 215, but the rear curtain light shielding blade 250 is also implemented on the rear surface of the opening 215 (imaging element 22 side). It is included in one aspect of the form. Further, in the present embodiment, the rear curtain light shielding blade 250 shields the entire area of the opening 215, but like the front curtain light shielding blade 220, a part of the area of the opening 215 may be shielded. In this case, the rear curtain light shielding blade 250 may be configured by a single blade, or may be configured so that the entire opening 215 is not covered by a plurality of blades.

  In the shutter device 21 configured as described above, when the release button is operated by the user, the front curtain light-shielding blade 220 first travels from the first retracted position 201 in the Y axis + direction. Then, after the elapse of a predetermined time from the start of traveling of the front curtain light shielding blade 220, the rear curtain light shielding blade 250 travels in the Y axis + direction from the first retreat position 201.

6 shows the position of the opening 215, the imaging surface 22a of the image sensor 22, the slit forming end 220U of the front curtain light shielding blade 220 retracted to the first retracted position 201, and the slit forming end 250B of the rear curtain light shielding blade 250. It is a figure which shows typically positional relationship.
As described above, the shutter device 21 of the present embodiment is a normally open type shutter device, and both the front curtain light shielding blade 220 and the rear curtain light shielding blade 250 are retracted to the first retraction position 201 before the start of photographing. ing. As shown in FIG. 6, in the state before the start of photographing, the upper edge 220U that is the slit forming end of the front curtain light shielding blade 220 is higher than the lower edge 250B that is the slit forming end of the rear curtain light shielding blade 250. It is away from 215U.
In FIG. 6, the position of each part in the Y-axis direction is defined as follows. The position of the upper edge 220U of the front curtain light shielding blade 220 retracted to the first retracted position 201 is set to zero, and the position of the lower edge 250B of the rear curtain light shielding blade 250 retracted to the first retracted position 201 is set to Y0. . It should be noted that the position (zero) of the upper edge 220U of the front curtain light shielding blade 220 retracted to the first retracted position 201 and the position of the lower edge 250B of the rear curtain light shielding blade 250 retracted to the first retracted position 201. (Y0) is also called a start position.
The position of the upper end 22U of the image pickup surface 22a of the image pickup element 22 is Y1, the position of the lower end 22B of the image pickup surface 22a is Y2, and the intermediate position between the upper end 22U and the lower end 22B, that is, the center position of the image pickup surface 22a is Yc. .

The distance Y1 until the upper end edge 220U of the front curtain light shielding blade 220 reaches the upper end 22U of the imaging surface 22a of the image sensor 22 after the start of traveling of the front curtain light shielding blade 220 is determined by the rear curtain light shielding after the rear curtain light shielding blade 250 starts traveling. It is considerably larger than the distance (Y1-Y0) until the lower end edge 250B of the blade 250 reaches the upper end 22U of the imaging surface 22a. In other words, the distance Y1 between the upper edge 220U of the front curtain light shielding blade 220 and the upper end 22U of the imaging surface 22a, and the distance (Y1-Y0) between the lower edge 250B of the rear curtain light shielding blade 250 and the upper edge 22U of the imaging surface 22a. The ratio Y1 / (Y1-Y0) becomes very large.
Therefore, in the vicinity of the upper end 22U of the imaging surface 22a of the image sensor 22, the moving speed of the upper edge 220U of the front curtain light shielding blade 220 may be considerably faster than the moving speed of the lower edge 250B of the rear curtain light shielding blade 250. .
On the other hand, in the vicinity of the lower end 22B of the imaging surface 22a of the imaging element 22, the distance Y2 between the upper edge 220U of the front curtain light shielding blade 220 and the lower end 22B of the imaging surface 22a, and the lower edge 250B of the rear curtain light shielding blade 250 and the imaging surface. The ratio Y2 / (Y2-Y0) to the distance (Y2-Y0) from the lower end 22B of 22a is smaller than the ratio Y1 / (Y1-Y0).
Accordingly, in the vicinity of the lower end 22B of the imaging surface 22a of the imaging element 22, the moving speed of the upper edge 220U of the front curtain light shielding blade 220 and the moving speed of the lower edge 250B of the rear curtain light shielding blade 250 are substantially equal.
Therefore, the exposure time varies depending on the position of the image pickup surface 22a of the image pickup device 22 in the Y-axis direction, which may cause uneven exposure.
In other words, when the front curtain light shielding blade and the rear curtain light shielding blade are set at the start position of the exposure operation, the distance between the slit forming end of the front curtain light shielding blade and the slit forming end of the rear curtain light shielding blade is different from each other. May cause uneven exposure due to a difference in traveling speed at the photographing opening of the slit forming end of the front curtain light shielding blade and the slit forming end of the rear curtain light shielding blade.

  Therefore, in the present embodiment, the image pickup element 22 is obtained by initially reducing and gradually increasing the drive torque transmitted to the front curtain drive arm 221 in order to move the front curtain light shielding blade 220 to the Y axis + side. The difference between the moving speed of the upper edge 220U of the front curtain light shielding blade 220 near the upper end 22U of the imaging surface 22a and the moving speed of the lower edge 250B of the rear curtain light shielding blade 250 is suppressed. Details will be described below.

FIG. 7 is a diagram for explaining the drive torque transmitted to the front curtain drive arm 221 and corresponds to FIG. In FIG. 7, the upper edge 220U of the front curtain light-shielding blade 220 is located in the vicinity of the intermediate position between the upper end 215U and the lower end 215B of the opening 215.
The drive torque transmitted to the front curtain drive arm 221 is Ta, and the drive torque of the front curtain drive first lever 310 is Tb. The distance between the board-side coupling portion 321 of the first curtain drive second lever 320 and the first curtain first drive pin 312 of the first curtain drive first lever 310 is La. The length of the arm that transmits the driving force from the first curtain drive first lever 310 to the first curtain drive second lever 320 via the first curtain first drive pin 312 is Lb. It should be noted that the arm length Lb is the tip length in the extending direction of the line segment connecting the board side connecting portion 321 of the first curtain drive second lever 320 and the first curtain first drive pin 312 of the first curtain drive first lever 310. This is the length between the substrate side connecting portion 311 of the curtain drive first lever 310 and the first curtain first drive pin 312. That is, the length between the board side connecting portion 311 and the first curtain first drive pin 312 is L, and the line segment connecting the board side connecting portion 311 and the first curtain first drive pin 312 is as follows. The angle Lb is θ, and the arm length Lb is (L × cos θ).
A driving force transmitted from the first curtain drive first lever 310 to the first curtain drive second lever 320 via the first curtain first drive pin 312 is F. The driving force F is applied to the board-side connecting portion 321 of the front curtain drive second lever 320 and the front curtain drive second at the contact position between the front curtain first drive pin 312 and the long hole 322 of the front curtain drive second lever 320. The first lever 310 acts in a direction perpendicular to the extending direction of the line connecting the first curtain first drive pin 312.

The driving force F transmitted from the first curtain drive first lever 310 to the first curtain drive second lever 320 via the first curtain first drive pin 312 is the drive torque Tb of the first curtain drive first lever 310 and the arm length Lb. Is expressed by the following formula (1).
F = Tb / Lb (1)

The drive torque Ta transmitted to the front curtain drive arm 221 is represented by the following formula (2) by the drive force F and the distance La.
Ta = F × La (2)

From the equations (1) and (2), the relationship between the drive torque Ta transmitted to the front curtain drive arm 221 and the drive torque Tb of the front curtain drive first lever 310 is expressed by the following equation (3). .
Ta = Tb × La / Lb (3)

  As is clear from Equation (3), the drive torque Ta transmitted to the front curtain drive arm 221 is the drive torque Tb of the front curtain drive first lever 310 and the board side coupling portion of the front curtain drive second lever 320. The arm of the first curtain drive first lever 310 that transmits the driving force via the first curtain first drive pin 312 is proportional to the distance La from 321 to the first curtain drive pin 312 of the first curtain drive first lever 310. It is inversely proportional to the length Lb.

  How the distance La and the arm length Lb change in accordance with the rotation of the first curtain drive first lever 310 will be described with reference to FIGS. FIG. 8 is a diagram illustrating a state of the shutter device 21 before an instruction to start photographing by operating the release button, and corresponds to FIG. FIG. 9 shows a state immediately before the front curtain light-shielding blade 220 moves further downward from the state shown in FIG. 7 and completes the retreat to the second retreat position (second position) 202 below the opening 215. FIG. 5 is a diagram corresponding to FIG. 4. The leading blade shading blade 220 changes from the state shown in FIG. 8 to the state shown in FIG. 7 as the leading blade driving first lever 310 rotates, and then changes to the state shown in FIG.

As is apparent from FIGS. 7 to 9, as the first curtain drive first lever 310 rotates counterclockwise about the board-side connecting portion 311, the engagement between the elongated hole 322 and the first curtain first drive pin 312 is performed. The alignment position moves and the distance La gradually increases.
As is apparent from FIGS. 7 to 9, the arm length Lb gradually decreases as the first curtain drive first lever 310 rotates counterclockwise about the board-side connecting portion 311.
Therefore, the ratio of the distance La to the arm length Lb, that is, La / Lb obtained by dividing the distance La by the arm length Lb, the first curtain drive first lever 310 is connected to the board side connecting portion 311. It becomes larger as it rotates counterclockwise around the center.
Therefore, as apparent from the equation (3), if the magnitude of the driving torque Tb of the first curtain driving first lever 310 is constant, the magnitude of the driving torque Ta transmitted to the leading curtain driving arm 221 is As the curtain drive first lever 310 rotates counterclockwise about the board side connecting portion 311, that is, as the front curtain light-shielding blade 220 travels from the first retracted position 201, it gradually increases.

  In the present embodiment, a front curtain actuator (not shown) has a spring as a drive source as described above. The magnitude of the drive torque Tb of the first curtain drive first lever 310 is substantially constant within the rotation range of the first curtain drive first lever 310 or as the first curtain drive first lever 310 rotates counterclockwise. Slightly weaken. In the present embodiment, the magnitude of the driving torque Tb of the first curtain drive first lever 310 slightly decreases as the front curtain drive first lever 310 rotates counterclockwise. However, in the present embodiment, the first curtain drive first lever 310 is rotated counterclockwise with respect to the decrease in the drive torque Tb accompanying the first curtain drive first lever 310 being rotated counterclockwise. The above increase in La / Lb is prevailing. Therefore, in the present embodiment, the magnitude of the drive torque Ta transmitted to the front curtain drive arm 221 is gradually increased as the front curtain drive first lever 310 rotates counterclockwise about the board side connecting portion 311. Become bigger.

FIG. 10A is a graph showing the change over time of the driving torque Ta transmitted to the front curtain drive arm 221 after the start of the shooting operation, and FIG. 10B is the rear curtain after the start of the shooting operation. 6 is a graph showing a change with time of drive torque transmitted to a drive arm 251; 10A and 10B, the horizontal axis represents the elapsed time, and the vertical axis represents the magnitude of the drive torque.
In the present embodiment, the drive torque Ta transmitted to the front curtain drive arm 221 increases with time as shown in FIG. 10A, and on the other hand, the drive torque transmitted to the rear curtain drive arm 251. As shown in FIG. 10B, the torque gradually decreases. Therefore, it is possible to suppress a difference between the moving speed of the upper edge 220U of the front curtain light shielding blade 220 and the moving speed of the lower edge 250B of the rear curtain light shielding blade 250 in the vicinity of the upper end 22U of the imaging surface 22a of the imaging element 22. The occurrence of uneven exposure can be suppressed.

FIG. 11 is a graph showing the running characteristic 401 of the front curtain light shielding blade 220 and the running characteristic 402 of the rear curtain light shielding blade 250 after the start of photographing. The upper edge 220U of the front curtain light shielding blade 220 and the lower end of the rear curtain light shielding blade 250 are shown. The time-dependent change of the position of the edge 250B in the Y-axis direction is shown.
According to the present embodiment, the difference Δt1 in the passage time between the upper edge 220U of the front curtain light shielding blade 220 and the lower edge 250B of the rear curtain light shielding blade 250 at the position Y1 of the upper end 22U of the imaging surface 22a of the image sensor 22, that is, The exposure time Δt1, the exposure time Δt2 at the intermediate position Yc, and the exposure time Δt3 at the position Y2 of the lower end 22B are substantially equal to each other. As a result, there is no difference in exposure time depending on the position in the Y-axis direction, so that uneven exposure can be suppressed.
In addition, the running curve shown by the broken line in FIG. 11 is shown in FIG. 10B instead of gradually increasing the driving torque Ta transmitted to the front curtain drive arm 221 as shown in FIG. An example of the running characteristics of the front curtain light-shielding blade 220 when the driving torque transmitted to the rear curtain drive arm 251 is gradually reduced is shown. Since the running curve of the broken line is a curve similar to the running characteristic 402 of the trailing curtain light-shielding blade 250, the exposure time Δt1 ′ at the position Y1 of the upper end 22U and the exposure time Δt3 ′ at the position Y2 of the lower end 22B are intermediate positions Yc. The exposure time Δt2 is different from that in FIG.

--- About the operation of the shutter device 21 ---
The shutter device 21 configured as described above operates as follows. Before the user operates the release button, as shown in FIG. 2, both the front curtain light shielding blade 220 and the rear curtain light shielding blade 250 are located at the first retracted position 201 and have passed through the photographing lens 11 shown in FIG. Subject light is incident on the image sensor 22 through the opening 215. A so-called live view display is performed in which an imaging signal is repeatedly read from the imaging element 22 and an image (preview image) corresponding to the imaging signal is displayed on the rear monitor 30.

  When the release button is operated by the user, the control device 26 releases the latch of the spring of the front curtain actuator (not shown). Thereby, the front curtain actuator rotates the front curtain drive first lever 310 counterclockwise in FIG. As a result, the front-curtain first drive pin 312 is driven along the elongated hole 322 of the front-curtain drive second lever 320, and the front-curtain drive second lever 320 is rotated about the board-side connecting portion 321. As a result, the front curtain drive arm 221 that rotates integrally with the front curtain drive second lever 320 and the front curtain driven arm 231 are parallel to the XY plane with the substrate side coupling portion 222 and the substrate side coupling portion 232 as the center. The front curtain light-shielding blade 220 travels from the first retreat position 201 in the Y-axis + direction. The lower edge 220B of the front curtain light shielding blade 220 starts to enter the opening 215, and light shielding of the imaging surface of the imaging element 22 behind the shutter is started. The image sensor 22 resets accumulated charges (pixel reset) in synchronization with the movement of the front curtain light shielding blade 220 for the pixels in the light shielded region. As shown in FIG. 3, when the upper edge 220U of the front curtain light-shielding blade 220 passes through the area of the image sensor 22 that is shielded by the front curtain light-shielding blade 220, the imaging surface of the image sensor 22 becomes the upper edge 220U. Exposure is started and electric charge is accumulated for the imaging region and the pixel through which has passed. In this manner, when the front curtain light-shielding blade 220 moves to the second retraction position 202 with the upper end edge 220U traveling to the Y axis + side from the lower end 215B of the opening 215, the image sensor 22 Pixel reset and exposure, that is, charge accumulation is performed.

  The control device 26 follows (synchronizes) the front curtain light-shielding blade 220 traveling in the Y-axis + direction and controls the pixel reset timing for each pixel row along the X-axis direction constituting the image sensor 22. To do. In other words, the control device 26 resets the pixel in the range shielded by the front curtain light shielding blade 220 of the image sensor 22.

  When the time corresponding to the exposure time elapses after the front curtain light-shielding blade 220 starts traveling, the control device 26 releases the latch of the spring of the unillustrated rear curtain actuator. As a result, the rear curtain actuator rotates the rear curtain drive lever 330 counterclockwise in FIG. As a result, the rear curtain drive pin 282 rotates along the elongated hole 270 in the counterclockwise direction in the drawing. As a result, the rear-curtain drive arm 251 and the rear-curtain driven arm 261 are driven to rotate in a plane parallel to the XY plane with the substrate-side connecting portion 252 and the substrate-side connecting portion 262 as the center, and the rear-curtain light-shielding blade 250 is first retracted. The vehicle travels from the position 201 in the Y axis + direction.

  Thus, the leading blade shading blade 220 starts traveling in the Y axis + direction, and the trailing curtain shading blade 250 starts traveling in the Y axis + direction after the elapse of time corresponding to the exposure time. The image sensor 22 after reset receives subject light only between the upper edge 220U (FIG. 3) of the front curtain light shielding blade 220 and the lower edge 250B of the lowermost blade of the rear curtain light shielding blade 250 for the exposure time. Incident. The image sensor 22 is exposed by the subject light.

Thereafter, the rear curtain light shielding blade 250 moves to a light shielding position that covers the entire opening 215.
The control device 26 controls the image sensor 22 to sequentially start pixel reading from the pixel row at the Y axis-side end. After the readout of the imaging signals from all the pixel rows is completed, the control device 26 outputs a drive signal from a power supply unit (not shown) to drive a reset motor (not shown). As a result, the front curtain light shielding blade 220 and the rear curtain light shielding blade 250 move in the Y-axis-direction and are stored in the first retracted position 201, and the springs of the front curtain actuator and the rear curtain actuator are charged. Thus, the operation control of the shutter device 21 at the time of photographing ends.

  In the present embodiment, as described above, the front curtain light shielding blade 220 and the rear curtain light shielding blade 250 are stored in the first retreat position 201 until the start of photographing. Therefore, as compared with the case where the front curtain light shielding blade 220 and the rear curtain light shielding blade 250 are stored in positions facing each other with the opening 215 interposed therebetween, the front curtain light shielding blade 220 travels to the charge position when shooting starts. There is no need to let them. Therefore, occurrence of a release time lag is suppressed.

  The front curtain drive mechanism 203 in the above-described embodiment can be applied to the following types of shutter devices. For example, the front-curtain drive mechanism 203 in the above-described embodiment is a normally open type shutter device, and the front-curtain light-shielding blade and the rear-curtain light-shielding blade are outside the shutter opening in the shooting preparation state before the start of shooting. The present invention can be applied to the shutter device that retracts to the same retracted position, that is, the shutter device 21 described above. Alternatively, the front-curtain drive mechanism 203 in the above-described embodiment is a normally open type shutter device, and the front-curtain shading blade is in the retracted position on the outer side on one side of the shutter opening in the photographing preparation state before the photographing is started. And the rear curtain light-shielding blade can be applied to a shutter device that retreats to a retreat position outside the other side of the shutter opening. The front curtain drive mechanism 203 in the above-described embodiment can be applied to a normally closed type shutter device.

According to the embodiment described above, the following operational effects can be obtained.
(1) The shutter device 21 includes a substrate 210 having a shutter opening 215, and a front curtain light shielding blade 220 that moves from a first retraction position 201 outside the shutter opening 215 to a second retraction position 202 different from the first retraction position 201. A first curtain driving second lever 320 that rotates about the substrate side connecting portion 222 to move the first curtain light shielding blade 220 between the first retracted position 201 and the second retracted position 202; A first curtain drive first lever 310 that has a first curtain first drive pin 312 that engages with the two lever 320 and that rotates about the board-side connecting portion 311 by a drive force from the first curtain actuator. The board-side connecting portion 311 and the tip in the direction connecting the distance La between the board-side connecting portion 321 and the position of the first-curtain first drive pin 312 and the position of the substrate-side connecting portion 321 and the first-curtain first drive pin 312. The ratio of the arm length Lb to the position of the curtain first drive pin 312 changes with the rotation of the first curtain drive first lever 310.
Thus, the magnitude of the drive torque Ta transmitted to the front curtain drive arm 221 can be changed according to the rotation of the front curtain drive first lever 310. Accordingly, by constructing the driving torque Ta transmitted to the front curtain driving arm 221 as the front curtain light-shielding blade 220 moves to the Y axis + side, the vicinity of the upper end 22U of the imaging surface 22a of the imaging element 22 is increased. It is possible to suppress a difference between the moving speed of the upper edge 220U of the front curtain light shielding blade 220 and the moving speed of the lower edge 250B of the rear curtain light shielding blade 250.
As a result, there is no difference in exposure time depending on the position in the Y-axis direction, so that uneven exposure can be suppressed.

(2) The driving torque Ta of the front curtain driving second lever 320 increases as the arm length Lb with respect to the distance La decreases as the front curtain driving first lever 310 rotates. As a result, the driving torque Ta transmitted to the front curtain drive arm 221 increases as the front curtain light shielding blade 220 moves to the Y axis + side, so that the front curtain light shielding in the vicinity of the upper end 22U of the imaging surface 22a of the image sensor 22 is achieved. It is possible to suppress a difference between the moving speed of the upper edge 220U of the blade 220 and the moving speed of the lower edge 250B of the trailing curtain light blocking blade 250. Therefore, there is no difference in exposure time depending on the position in the Y-axis direction, so that uneven exposure can be suppressed.

(3) The front curtain drive second lever 320 has a long hole 322 with which the front curtain first drive pin 312 is engaged. The position of the first curtain drive pin 312 in the elongated hole 322 is moved by the rotation of the first curtain drive first lever 310. As a result, the driving torque Ta transmitted to the front curtain drive arm 221 as the front curtain light-shielding blade 220 moves to the Y axis + side can be strengthened with a simple configuration, and an increase in cost can be suppressed.

(4) The substrate 210 having the shutter opening 215, the front curtain light shielding blade 220 that moves from the first retraction position 201 to the second retraction position 202, and the second retraction from the first retraction position 201 after the movement of the front curtain light shielding blade 220. A rear curtain light shielding blade 250 that moves to a position 202 and a front curtain drive mechanism 203 that drives the front curtain light shielding blade 220 are provided. The front-curtain drive mechanism 203 includes a front-curtain drive first lever 310 that rotates about the board-side connecting portion 311 by a driving force from the front-curtain actuator, and a long hole 322 that engages with the front-curtain drive first lever 310. And a first curtain drive second lever 320 that rotates around the substrate side coupling portion 321 different from the substrate side coupling portion 311 by the rotation of the first curtain drive first lever 310 and moves the first curtain light shielding blade 220. . A direction connecting the distance La between the board-side connecting portion 321 and the position of the first curtain first drive pin 312 in the elongated hole 322 and the position of the first-curtain first drive pin 312 in the elongated board 322. The ratio of the arm length Lb between the board-side connecting portion 311 and the position of the first curtain first drive pin 312 in the elongated hole 322 is changed by the rotation of the first curtain drive first lever 310.
Thus, the magnitude of the drive torque Ta transmitted to the front curtain drive arm 221 can be changed according to the rotation of the front curtain drive first lever 310. Accordingly, by constructing the driving torque Ta transmitted to the front curtain driving arm 221 as the front curtain light-shielding blade 220 moves to the Y axis + side, the vicinity of the upper end 22U of the imaging surface 22a of the imaging element 22 is increased. It is possible to suppress a difference between the moving speed of the upper edge 220U of the front curtain light shielding blade 220 and the moving speed of the lower edge 250B of the rear curtain light shielding blade 250.
As a result, there is no difference in exposure time depending on the position in the Y-axis direction, so that uneven exposure can be suppressed.

--- Second Embodiment ---
A second embodiment of the shutter device will be described with reference to FIGS. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and different points will be mainly described. Points that are not particularly described are the same as those in the first embodiment. In the present embodiment, the driving force is transmitted to the front curtain drive arm 221 mainly by a link mechanism described later, which is different from the first embodiment.

  12 to 14 are diagrams illustrating an internal structure of the shutter device 21 </ b> A of the second embodiment, viewed from the image sensor 22 side, that is, the back side of the digital camera 1. FIG. 12 is a diagram illustrating a state of the shutter device 21A before an instruction to start shooting by operating the release button. FIG. 13 shows the shutter device 21 </ b> A after the front button shading blade 220 starts moving downward in the figure so as to cross the opening 215 after the user operates the release button and gives an instruction to start shooting. It is a figure which shows a state, and shows the state before the trailing curtain light-shielding blade 250 starts moving. FIG. 14 is a diagram illustrating a state in which the front curtain light-shielding blade 220 is further moved downward from the state illustrated in FIG. 3 and is retracted to a second retraction position (second position) 202 below the opening 215. The state before the trailing curtain light-shielding blade 250 starts moving is shown.

  As shown in FIG. 14, the shutter device 21A includes a substrate 210, a front curtain light shielding blade 220, a rear curtain light shielding blade 250, a front curtain drive arm 221, a front curtain driven arm 231, and a first curtain drive first lever. 310A, front curtain drive second lever 320A, link lever 330, rear curtain drive arm 251, rear curtain driven arm 261, rear curtain drive lever 330, front curtain actuator (not shown), and not shown And a rear curtain actuator. The front curtain drive arm 221, the front curtain driven arm 231, the front curtain drive first lever 310 </ b> A, the front curtain drive second lever 320 </ b> A, and the link lever 330 are included in the front curtain drive mechanism 203 </ b> A.

  In the hole 224 of the front curtain drive arm 221, the front curtain second drive pin 281 penetrating through the long hole 240 of the substrate 210 is inserted into the hole 224 from the front side of the page, that is, from the back side of the digital camera 1. The front curtain second drive pin 281 is attached to the front curtain drive second lever 320A.

The front curtain drive second lever 320A has a substrate side connecting portion 321 at one end, and a front curtain second drive pin 281 is attached to the other end. Like the front curtain drive second lever 320 in the first embodiment, the front curtain drive second lever 320A is pivotally supported coaxially with the front curtain drive arm 221 with respect to the substrate 210, and is attached to the other end. Since the front curtain second drive pin 281 thus inserted is inserted into the hole 224 of the front curtain drive arm 221, it rotates integrally with the front curtain drive arm 221 around the board-side coupling portions 222 and 321.
The front curtain second drive pin 281 is attached to one end of a link lever 330 described below. That is, the other end of the front curtain drive second lever 320A and one end of the link lever 330 are connected to each other by the front curtain second drive pin 281 so as to be rotatable.

  The link lever 330 is a lever that connects the front curtain drive second lever 320A and the first curtain drive first lever 310A described below. As described above, the front curtain second drive pin 281 is attached to one end of the link lever 330, and the front curtain first drive pin 312 is attached to the other end. Thus, one end of the link lever 330 is pivotally connected to the front curtain drive second lever 320A by the front curtain second drive pin 281 and the other end is connected to the front curtain first drive pin 312 by the front curtain first drive pin 312. The lever 310A and the lever 310A are pivotably connected to each other.

  The first curtain drive first lever 310A has a substrate side connecting portion 311 at one end, and is pivotally supported by the substrate side connecting portion 311 on the back surface of the substrate 210 (on the image sensor 22 side) so as to be rotatable. A first curtain first drive pin 312 is attached to the other end of the first curtain drive first lever 310A.

  The first curtain drive first lever 310A is driven by a front curtain actuator (not shown). When the front-curtain drive first lever 310A is rotated about the substrate-side connecting portion 311 by the front-curtain actuator, the front-curtain drive second lever 320A connected via the link lever 330 moves the substrate-side connecting portion 321. It is rotated to the center. As a result, the front curtain drive arm 221 and the front curtain driven arm 231 that rotate together with the front curtain drive second lever 320 </ b> A are rotated about the board side connection part 222 and the board side connection part 232. Therefore, the front curtain light-shielding blade 220 moves through the opening 215 of the substrate 210 in the Y-axis direction.

FIGS. 15 to 17 are diagrams for explaining the drive torque transmitted to the front curtain drive arm 221 in the second embodiment, and correspond to FIG. 12. The drive torque transmitted to the front curtain drive arm 221 is Tc, and the drive torque of the front curtain drive first lever 310A is Td. The distance between the board side coupling portion 321 of the front curtain drive second lever 320A and the front curtain second drive pin 281 is Lc. The length of the arm through which the first curtain drive first lever 310A transmits the driving force via the link lever 330 is Ld. As shown in FIG. 16, the arm length Ld is a line segment connecting the board side connecting portion 321 of the first curtain drive second lever 320A and the first curtain second drive pin 281 of the first curtain drive first lever 310A. Is the length between the board side connecting portion 311 of the first curtain drive first lever 310A and the first curtain second drive pin 281 in the extending direction of.
Of the driving force transmitted from the first curtain drive first lever 310A to the first curtain drive second lever 320A via the link lever 330, the component contributing as the drive torque to the first curtain drive second lever 320A is F1. That is, the driving force component F1 extends in the direction in which the segment connecting the board-side connecting portion 321 of the first curtain drive second lever 320 and the first curtain second drive pin 281 with respect to the first curtain second drive pin 281 extends. Acting in the direction perpendicular to

The driving force component F1 is expressed by the following formula (1) by the driving torque Td of the first curtain driving first lever 310A and the arm length Ld.
F1 = Td / Ld (4)

The driving torque Tc transmitted to the front curtain driving arm 221 is expressed by the following equation (2) by the driving force component F1 and the distance Lc.
Tc = F1 × Lc (5)

From the equations (4) and (5), the relationship between the drive torque Tc transmitted to the front curtain drive arm 221 and the drive torque Td of the first curtain drive first lever 310A is expressed by the following equation (6). .
Tc = Td × Lc / Ld (6)

  As is apparent from the equation (6), the driving torque Tc transmitted to the front curtain driving arm 221 is proportional to the driving torque Td of the first curtain driving first lever 310A and the distance Lc, and the arm length Ld. Inversely proportional. It should be noted that the distance Lc between the board side coupling portion 321 of the front curtain drive second lever 320A and the front curtain second drive pin 281 is unchanged.

  How the arm length Ld changes in accordance with the rotation of the first curtain drive first lever 310A will be described with reference to FIGS. FIG. 16 shows the shutter device 21 </ b> A after the front shutter shading blade 220 starts to move downward in the figure so as to cross the opening 215 after the user operates the release button and is instructed to start photographing. It is a figure which shows a state, and is a figure equivalent to FIG. FIG. 17 is a diagram illustrating a state where the front curtain light-shielding blade 220 further moves downward from the state illustrated in FIG. 16 and is retracted to a second retraction position (second position) 202 below the opening 215. It is a figure equivalent to FIG. The front curtain shading blade 220 changes from the state shown in FIG. 15 to the state shown in FIG. 16 with the rotation of the first curtain drive first lever 310A, and then changes to the state shown in FIG.

As apparent from FIGS. 15 to 17, the arm length Ld gradually decreases as the first curtain drive first lever 310 rotates counterclockwise about the board-side connecting portion 311. Therefore, the ratio between the length of the distance Lc and the length of the arm Ld, that is, Lc / Ld obtained by dividing the length of the distance Lc by the length of the arm Ld, the first curtain drive first lever 310A is connected to the board side connecting portion 311. It becomes larger as it rotates counterclockwise around the center.
Therefore, as apparent from the equation (6), if the magnitude of the driving torque Td of the first curtain driving first lever 310A is constant, the magnitude of the driving torque Tc transmitted to the leading curtain driving arm 221 is As the curtain drive first lever 310A rotates counterclockwise about the board side connecting portion 311, that is, as the front curtain light shielding blade 220 travels from the first retracted position 201, the first curtain drive lever 310 </ b> A gradually increases.

  In the present embodiment as well, as in the first embodiment, the magnitude of the driving torque Td of the first curtain drive first lever 310A increases as the first curtain drive first lever 310A rotates counterclockwise. Slightly weaken. However, in the present embodiment, the first curtain drive first lever 310A is rotated counterclockwise with respect to the decrease in the drive torque Td associated with the first curtain drive first lever 310A rotating counterclockwise. The above increase in Lc / Ld is prevailing. Therefore, in the present embodiment, the magnitude of the drive torque Tc transmitted to the front curtain drive arm 221 is gradually increased as the front curtain drive first lever 310A rotates counterclockwise around the board side connecting portion 311. Become bigger.

In the present embodiment, in addition to the operational effects of the first embodiment, the following operational effects are achieved.
(1) The shutter device 21A includes a first curtain drive first lever 310A that rotates about a board-side connecting portion 311 and a link lever 330 that is rotatably connected to the first curtain drive first lever 310A. The front curtain second drive pin 281 is a connecting member that connects the link lever 330 and the front curtain drive first lever 310A. As a result, the driving torque Ta transmitted to the front curtain drive arm 221 as the front curtain light-shielding blade 220 moves to the Y axis + side can be strengthened with a simple configuration, and an increase in cost can be suppressed.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
(Modification 1)
In each of the above-described embodiments, the image pickup element 22 is obtained by initially reducing and gradually increasing the driving torque transmitted to the front curtain drive arm 221 in order to move the front curtain light shielding blade 220 to the Y axis + side. The difference between the moving speed of the upper edge 220U of the front curtain light shielding blade 220 near the upper end 22U of the imaging surface 22a and the moving speed of the lower edge 250B of the rear curtain light shielding blade 250 is suppressed.
That is, in each of the above-described embodiments, the lower end edge 250B of the rear curtain light shielding blade 250 is controlled by suppressing the moving speed of the upper edge 220U of the front curtain light shielding blade 220 in the vicinity of the upper end 22U of the imaging surface 22a of the imaging element 22. The occurrence of a difference from the moving speed is suppressed.
On the other hand, in this modification, the movement speed of the upper edge 220U of the front curtain light shielding blade 220 is increased by increasing the moving speed of the lower edge 250B of the rear curtain light shielding blade 250 in the vicinity of the upper end 22U of the imaging surface 22a of the imaging element 22. Suppresses differences in speed.

In other words, in the present modification, the drive torque transmitted to the front curtain drive arm 221 in order to move the rear curtain light-shielding blade 250 to the Y axis + side is initially increased and gradually decreased, so that the imaging of the image sensor 22 is performed. A difference between the moving speed of the upper edge 220U of the front curtain light shielding blade 220 near the upper end 22U of the surface 22a and the moving speed of the lower edge 250B of the rear curtain light shielding blade 250 is suppressed.
Specifically, for example, the first curtain drive first lever 310 and the first curtain drive second lever 320 are configured symmetrically in the Y-axis direction with respect to the center position Y of the imaging surface 22a. The rear curtain drive arm 251 may be driven by the second lever. That is, the rear curtain light-shielding blade 250 is driven by a rear curtain drive mechanism having the same configuration as the above-described front curtain drive mechanism 203.
The rear curtain drive lever 330 may be configured such that the front curtain drive arm 221 is driven by a front curtain drive lever configured symmetrically in the Y axis direction with respect to the center position Y of the imaging surface 22a. That is, the front curtain light blocking blade 220 is driven by the front curtain drive mechanism having the same configuration as the rear curtain drive mechanism 204 described above.

FIG. 18A is a graph showing the change over time of the drive torque transmitted to the front curtain drive arm 221 after the start of photographing when the front curtain drive lever is configured as described above. ) Is a graph showing the change over time of the driving torque transmitted to the rear curtain drive arm 251 after the start of photographing when the rear curtain drive first lever and the rear curtain drive second lever are configured as described above. . 18A and 18B, the horizontal axis represents the elapsed time, and the vertical axis represents the magnitude of the drive torque.
In the present modification, as shown in FIG. 18B, the driving torque transmitted to the trailing curtain driving arm 251 is initially large and decreases with time. Thereby, it is possible to suppress a difference between the moving speed of the upper edge 220U of the front curtain light shielding blade 220 and the moving speed of the lower edge 250B of the rear curtain light shielding blade 250 in the vicinity of the upper end 22U of the imaging surface 22a of the imaging element 22. .

FIG. 19 is a graph showing the running characteristics 403 of the front curtain light-shielding blade 220 and the travel characteristics 404 of the rear curtain light-shielding blade 250 after the start of photographing in this modification, and the upper edge 220U and the rear curtain of the front curtain light-shielding blade 220. The time-dependent change of the position of the lower end edge 250B of the light shielding blade 250 in the Y-axis direction is shown.
According to this modification, the difference Δt1 in the passage time between the upper edge 220U of the front curtain light shielding blade 220 and the lower edge 250B of the rear curtain light shielding blade 250 at the position Y1 of the upper end 22U of the imaging surface 22a of the image sensor 22, that is, exposure. The time Δt1, the exposure time Δt2 at the intermediate position Yc, and the exposure time Δt3 at the position Y2 of the lower end 22B are substantially equal to each other. As a result, there is no difference in exposure time depending on the position in the Y-axis direction, so that uneven exposure can be suppressed.
Note that the travel curve indicated by the broken line in FIG. 19 shows that the driving torque transmitted to the trailing curtain drive arm 251 is initially increased as shown in FIG. The driving torque transmitted to the front curtain drive arm 221 shown in FIG. 6 shows an example of the running characteristics of the rear curtain light shielding blade 250 when it is not initially increased but gradually reduced. Since the running curve of the broken line is a curve similar to the running characteristic 403 of the front-curtain light shielding blade 220, the exposure time Δt1 ′ at the position Y1 of the upper end 22U and the exposure time Δt3 ′ at the position Y2 of the lower end 22B are intermediate positions Yc. The exposure time Δt2 is different from that in FIG.

  In the above description, the drive source of the front curtain actuator and the rear curtain actuator is the spring, but it may be an electric motor.

  Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other embodiments conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1; Digital camera, 20; Camera body, 21 and 21A; Shutter apparatus, 201; 1st evacuation position (1st position), 202; 2nd evacuation position (2nd position), 203; 10; shutter substrate (substrate), 215; shutter opening (opening), 220; front curtain light shielding blade 221; front curtain drive arm, 222; substrate side connecting portion, 250; rear curtain light shielding blade, 281; Pin, 310, 310A; first curtain drive first lever, 311 and 321; substrate side connecting portion, 312; first curtain first drive pin, 320; front curtain drive second lever, 322; oblong hole, 330; link lever

Claims (11)

A substrate having an opening;
A light shielding member that moves from a first position outside the opening to a second position different from the first position;
A moving member that rotates about a first axis to move the light shielding member between the first position and the second position;
A rotating member that has an engaging portion that engages with the moving member, and that rotates about a second axis by a driving force from the driving portion;
With
A first length between the first shaft and the engaging portion; and a second length between the second shaft and the engaging portion in a direction connecting the first shaft and the engaging portion. A shutter device in which a ratio of the rotation member changes with rotation of the rotating member. The shutter device according to claim 1,
The moving device is a shutter device in which the torque by the driving force increases as the second length with respect to the first length decreases as the rotating member rotates. The shutter device according to claim 1 or 2,
The moving member has a long hole with which the engaging portion is engaged,
A shutter device in which a position of the engaging portion in the elongated hole is moved by rotation of the rotating member. The shutter device according to claim 1 or 2,
The rotating member includes a first member that rotates about the second axis and a second member that is rotatably connected to the first member;
The engaging portion is a shutter device that is a connecting member that connects the second member and the moving member. In the shutter device according to any one of claims 1 to 4,
A shutter device further comprising a second light shielding member that moves from a third position outside the opening to a fourth position different from the third position. The shutter device according to claim 5,
The first position and the third position are shutter devices located on the same side with respect to the opening. A substrate having an opening;
A first light blocking member that moves from a first position to a second position;
A second light shielding member that moves from a third position to a fourth position after the movement of the first light shielding member;
A drive mechanism for driving one of the first and second light shielding members,
The driving mechanism includes a rotating member that rotates about a first axis by a driving force from a driving unit, and an engaging unit that engages with the rotating member, and is different from the first axis due to the rotation of the rotating member. A moving member that rotates about the second axis to move the light shielding member,
A first length between the second shaft and the engaging portion; and a second length between the first shaft and the engaging portion in a direction connecting the second shaft and the engaging portion. A shutter device in which a ratio of the rotation member changes with rotation of the rotating member. The shutter device according to claim 7.
The first position and the second position are respectively one side and the other side of the substrate across the opening,
The third position and the fourth position are shielding positions that shield the one side and the opening, respectively, across the opening,
The first light-shielding member has one end that first enters the opening in the movement from the first position to the second position and the other end opposite to the one end.
The second light shielding member has one end that first enters the opening in the movement from the third position to the fourth position, and the other end opposite to the one end.
The distance between the other end of the first light shielding member and the opening at the first position is greater than the distance between the one end of the second light shielding member and the opening at the third position. . The shutter device according to claim 8, wherein
The drive mechanism drives the first light shielding member;
The ratio is such that the ratio increases as the rotating member rotates. The shutter device according to claim 8, wherein
The drive mechanism drives the second light shielding member;
The ratio is such that the ratio decreases as the rotating member rotates. The shutter device according to any one of claims 1 to 10,
An image pickup apparatus comprising: an image pickup device that picks up an image of a light beam that has passed through the opening.

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