U.S. patent application number 15/978440 was filed with the patent office on 2018-09-13 for shutter device and image-capturing apparatus.
This patent application is currently assigned to NIKON CORPORATION. The applicant listed for this patent is NIKON CORPORATION. Invention is credited to Masanori HASUDA, Kenji OHASHI, Takeshi UEKI.
Application Number | 20180259829 15/978440 |
Document ID | / |
Family ID | 55857653 |
Filed Date | 2018-09-13 |
United States Patent
Application |
20180259829 |
Kind Code |
A1 |
HASUDA; Masanori ; et
al. |
September 13, 2018 |
SHUTTER DEVICE AND IMAGE-CAPTURING APPARATUS
Abstract
A shutter device includes: a substrate having an opening; a
first light-shielding member that moves from a first position
outside the opening of the substrate to a second position outside
the opening to shield the opening, the second position being
different from the first position; a second light-shielding member
that partly shields the opening while moving from the first
position to the second position; a first moving member that has a
protrusion moving along a hole provided in the substrate to move
the first light-shielding member; a second moving member that is
coupled to the second light-shielding member and moves together
with the second light-shielding member; and a third moving member,
located outside a movement range of the protrusion during the
second light-shielding member being located in the first position,
that is coupled to the second light-shielding member and moves
together with the second light-shielding member.
Inventors: |
HASUDA; Masanori;
(Fujisawa-shi, JP) ; OHASHI; Kenji; (Tokyo,
JP) ; UEKI; Takeshi; (Kawasaki-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NIKON CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
NIKON CORPORATION
Tokyo
JP
|
Family ID: |
55857653 |
Appl. No.: |
15/978440 |
Filed: |
May 14, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15521974 |
Aug 25, 2017 |
9995989 |
|
|
PCT/JP2015/080815 |
Oct 30, 2015 |
|
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15978440 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03B 9/42 20130101; G03B
9/18 20130101; G03B 9/36 20130101; H04N 5/2254 20130101 |
International
Class: |
G03B 9/36 20060101
G03B009/36; G03B 9/18 20060101 G03B009/18; H04N 5/225 20060101
H04N005/225 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 31, 2014 |
JP |
2014-223428 |
Claims
1. A shutter device, comprising: a substrate having an opening; a
first shielding member that moves from a first area outside the
opening of the substrate to a second area outside the opening to
shield at least part of the opening, the second area being
different from the first area; a second shielding member that
partly shields the opening while moving from the first area to the
second area; a first moving member that has a protrusion moving
along a hole provided in the substrate to move the first shielding
member; and a second moving member, located outside a movement
range of the protrusion while the second shielding member is
located in the first area, that is coupled to the second shielding
member and moves together with the second shielding member.
2. The shutter device according to claim 1, further comprising: a
third moving member that is coupled to the second shielding member
and is located outside a movement range of the protrusion while the
second shielding member is located in the first area.
3. The shutter device according to claim 1, wherein: the second
moving member is curved so as to locate between a movement range of
the first moving member and the opening while the second shielding
member is located in the first area.
4. The shutter device according to claim 2, wherein: the second
moving member and the third moving member constitute a parallel
link mechanism for moving the second shielding member; and the
third moving member at least partly overlaps the second moving
member.
5. The shutter device according to claim 4, wherein: each of the
second moving member and the third moving member is coupled to the
second shielding member on one of surfaces of the second shielding
member; and one of the second moving member and the third moving
member has a step in an area where the members overlap each
other.
6. The shutter device according to claim 4, wherein: the second
moving member and the third moving member are coupled to the second
shielding member on opposite surfaces of the second shielding
member.
7. An image-capturing apparatus, comprising: the shutter device
according to claim 1; and an image sensor that receives subject
light through the shutter device.
Description
RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
patent application Ser. No. 15/521,974, filed Aug. 25, 2017, which
in turn is a national stage application of PCT/JP2015/080815, filed
Oct. 30, 2015. This application also claims priority to Japanese
Patent Application No. 2014-223428, filed Oct. 31, 2014. The
disclosures of these prior applications are hereby incorporated by
reference in their entirety.
TECHNICAL FIELD
[0002] The present invention relates to a shutter device and an
image-capturing apparatus.
BACKGROUND ART
[0003] So-called normally open type shutter devices having a front
curtain light-shielding blade and a rear curtain light-shielding
blade are known. In an electronic camera equipped with such a
shutter device, a front curtain light-shielding blade is withdrawn
from a photographic opening of the shutter device to one side in a
shift direction of light-shielding blades, while a rear curtain
light-shielding blade is withdrawn to the other side in order to
display a preview image in a photographing preparation state before
an actual exposure (see PTL1, for example).
CITATION LIST
Patent Literature
[0004] PTL1: Japanese Laid-Open Patent Publication. No.
2008-164804
SUMMARY OF INVENTION
Technical Problem
[0005] In the electronic camera provided with the shutter device
described in PTL1, the front curtain light-shielding blade which
has been withdrawn from the photographic opening to one side is
shifted toward the other side to shield the photographic opening,
so that a reset operation of the image sensor is performed before
the actual exposure. Then, the front curtain light-shielding blade
and the rear curtain light-shielding blade are shifted toward the
one side with a predetermined time difference to expose an image
sensor. A release time lag is thus increased.
[0006] However, no specific configuration of a shutter device that
can further reduce the release time lag has been proposed.
Solution to Problem
[0007] According to the 1st aspect of the present invention, a
shutter device comprises: a substrate having an opening; a first
light-shielding member that moves from a first position outside the
opening of the substrate to a second position outside the opening
to shield the opening, the second position being different from the
first position; a second light-shielding member that partly shields
the opening while moving from the first position to the second
position; a first moving member that has a protrusion moving along
a hole provided in the substrate to move the first light-shielding
member; a second moving member that is coupled to the second
light-shielding member and moves together with the second
light-shielding member; and a third moving member, located outside
a movement range of the protrusion during the second
light-shielding member being located in the first position, that is
coupled to the second light-shielding member and moves together
with the second light-shielding member.
[0008] According to the 2nd aspect of the present invention, it is
preferred that in the shutter device according to the 1st aspect,
the third moving member is curved so as to locate between a
movement range of the first moving member and the opening while the
second light-shielding member is located in the first position.
[0009] According to the 3rd aspect of the present invention, it is
preferred that in the shutter device according to the 1st or 2nd
aspect, the second moving member and the third moving member
constitute a parallel link mechanism for moving the second
light-shielding member; and the third moving member at least partly
overlaps the second moving member.
[0010] According to the 4th aspect of the present invention, it is
preferred that in the shutter device according to the 3rd aspect,
each of the second moving member and the third moving member is
coupled to the second light-shielding member on one of surfaces of
the second light-shielding member; and one of the second moving
member and the third moving member has a step in an area where the
members overlap each other.
[0011] According to the 5th aspect of the present invention, it is
preferred that in the shutter device according to the 3rd aspect,
the second moving member and the third moving member are coupled to
the second light-shielding member on opposite surfaces of the
second light-shielding member.
[0012] According to the 6th aspect of the present invention, an
image-capturing apparatus comprises: the shutter device according
to any one of 1st to 5th aspects; and an image sensor that receives
subject light through the shutter device.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1 is a view illustrating a configuration of main
components of a digital camera which is an image-capturing
apparatus according to an embodiment.
[0014] FIG. 2 is a view illustrating an internal configuration of a
shutter device.
[0015] FIG. 3 is a view illustrating the internal configuration of
the shutter device.
[0016] FIG. 4 is a view illustrating the internal configuration of
the shutter device.
[0017] FIG. 5 is a view illustrating a front curtain driven
arm.
[0018] FIG. 6 is a schematic view illustrating how a front curtain
driving arm and the front curtain driven arm overlap each
other.
[0019] FIG. 7 is a view illustrating variations.
DESCRIPTION OF EMBODIMENTS
[0020] An image-capturing apparatus including a shutter device
according to an embodiment will be described with reference to the
drawings.
[0021] FIG. 1 is a view illustrating a configuration of main
components of a digital camera 1 which is an image-capturing
apparatus according to an embodiment. As illustrated in FIG. 1, the
digital camera 1 is a so-called mirrorless camera including a
camera body 20 and a lens barrel 10 that is removably attached to
the camera body 20 with a lens mount 9 therebetween. The digital
camera 1 may be a single lens reflex camera, instead of a
mirrorless camera.
[0022] The lens barrel 10 includes an image-forming optical system
11 and a diaphragm 12. The image-forming optical system 11 is an
optical system constituted by a plurality of lenses including a
focus adjusting lens, for forming a subject image on a
predetermined image-forming plane. The focus adjusting lens is
moved back and forth in an optical axis L direction by the
operation of a lens driving motor (not shown). FIG. 1 schematically
illustrates the image-forming optical system 11 as a single lens,
for convenience of illustration. The diaphragm 12 limits light flux
passing through the image-forming optical system 11, that is, an
amount of incident light.
[0023] The camera body 20 has a shutter device 21, an image sensor
22, and a controller 26 provided therein. The camera body 20 also
has a rear side monitor 30, which includes a display device such as
a liquid crystal display, provided on its rear side. The camera
body 20 further has an operating unit 40 provided thereon.
[0024] The image sensor 22 is an image sensor having a number of
pixels arranged in a matrix, such as a CMOS image sensor. The image
sensor 22 is arranged so that its image-capturing plane is
positioned on the image-forming plane of the image-forming optical
system 11. The image sensor 22 receives subject light through the
shutter device 21. In other words, the image sensor 22 captures the
subject image formed on the image-capturing plane by the
image-forming optical system 11 through the shutter device 21 and
outputs image-capturing signals to the controller 26. Furthermore,
various optical filters including an infrared cut filter are
provided on the image-capturing plane of the image sensor 22,
although not illustrated in FIG. 1. The plurality of pixels
constituting the image sensor 22 are two-dimensionally arranged in
a pixel row direction (the X axis direction in FIG. 2 described
later) and in a pixel column direction (the Y axis direction in
FIG. 2 described later) that is orthogonal to the pixel row
direction. The pixels are reset and the image-capturing signals are
read out for each of pixel rows at different positions in the pixel
column direction at different timings.
[0025] The shutter device 21 is provided on a front side (a subject
side) of the image sensor 22. The shutter device 21 is a so-called
focal plane shutter that is driven by a front curtain actuator and
a rear curtain actuator (not shown) in accordance with driving
signals from a power control unit (not shown) of a controller 26
described later, to shield light flux which would be incident onto
the image sensor 22 from the subject. Details of the shutter device
21 will be described later.
[0026] The controller 26, which is constituted by a microprocessor,
its peripheral circuits, and other circuits, controls components of
the digital camera 1 by reading and executing control programs
stored in advance in a storage medium (not shown) such as a flash
memory. The controller 26 performs various image processing
operations on the image-capturing signals output from the image
sensor 22 to generate image data of the subject image and record
the generated image data in a portable storage medium (not shown)
such as a memory card. The controller 26 controls operations of the
shutter device 21 and the image sensor 22, as described later. The
controller 26 has the power control unit (not shown) that functions
to control the operation of the shutter device 21.
[0027] The controller 26 may be made of electronic circuits having
functions equivalent to functions of the control programs.
[0028] The operating unit 40 includes various switches allocated to
various operating members operated by a user, and outputs operation
signals corresponding to operations of the operating members to the
controller 26. The operating members include, for example, a
release button, a menu button for displaying a menu screen on the
rear side monitor 30, a cross key that is operated for selecting
various settings and the like, a determination button for
determining the settings and the like selected with the cross key,
and a mode switching button for switching an operation mode of the
digital camera 1 between a photographing mode and a reproduction
mode.
[0029] Details of the shutter device 21 according to is embodiment
will now be described.
[0030] FIGS. 2 to 4 are views illustrating an internal
configuration of the shutter device 21 as seen from the
image-capturing sensor 22 side, that is, the rear side of the
digital camera 1. For convenience of explanation, a coordinate
system having the X axis and the Y axis will be defined as
illustrated in the figures. FIG. 2 is a view illustrating a state
of the shutter device 21 before a start of photographing is
instructed by an operation of the release button, where both a
front curtain light-shielding blade 220 and a rear curtain
light-shielding blade 250 described later have been withdrawn in a
first withdrawn position (a first position) 201 above a shutter
opening (an opening) 215. FIG. 3 illustrates a state of the shutter
device 21 after the user operates the release button to instruct
the start of photographing, where the front curtain light-shielding
blade 220 has started moving downward to traverse the opening 215,
while the rear curtain light-shielding blade 250 has not yet
started to move. FIG. 4 is a view illustrating a state where the
front curtain light-shielding blade 220 has moved further downward
from the position illustrated in FIG. 3 to withdraw into a second
withdrawn position (a second position) 202 below the opening 215,
while the rear curtain light-shielding blade 250 has not yet
started to move.
[0031] The shutter device 21 includes the substrate 210, the front
curtain light-shielding blade 220, the rear curtain light-shielding
blade 250, a front curtain driving arm 221, a front curtain driven
arm 231, a rear curtain driving arm 251, a rear curtain driven arm
261, the front curtain actuator (not shown), and the rear curtain
actuator (not shown). In this embodiment, each of the front curtain
actuator and the rear curtain actuator is made of an electric motor
or the like.
[0032] The substrate 210 is fixed in the camera body 20 and has an
opening 215 to expose the image sensor 22 with light flux from the
subject. The opening 215 is formed into a rectangular shape having
two sides extending in the X axis direction and two sides extending
along the Y axis direction. In the following description, a side of
the opening 215 on the negative Y axis side will be referred to as
an upper end 215U, a side on the positive Y axis side will be
referred to a bottom end 215B, and the length in the Y axis
direction between the upper end 215U and the bottom end 215B will
be denoted by L0.
[0033] Front Curtain
[0034] As well illustrated in FIG. 3, for example, the front
curtain driving arm 221 has a substrate-side coupling part 222 in
one end, at which the front curtain driving arm 221 is rotatably
pivoted by the substrate 210 on the rear side (the image sensor 22
side) of the substrate 210. The front curtain driven arm 231 has a
substrate-side coupling part 232 in one end, at which the front
curtain driven arm 231 is rotatably pivoted by the substrate 210 on
the rear side (the image sensor 22 side) of the substrate 210,
above the front curtain driving arm 221 in the figures. The front
curtain driving arm 221 has a light-shielding member-side coupling
part 223 at the other end, at which the front curtain
light-shielding blade 220 is rotatably coupled to the front curtain
driving arm 221 with a caulking pin. The front curtain driven arm
231 has a light-shielding member-side coupling part 233 at the
other end, at which the front curtain light-shielding blade 220 is
rotatably coupled to the front curtain driven arm 231 with a
caulking pin. The front curtain driving arias 221 and the front
curtain driven area 231 constitute a known parallel link mechanism
for moving the front curtain light-shielding blade 220.
[0035] It should be noted that the front curtain driving arm 221
and the front curtain driven arm 231 are provided below the rear
curtain driving arm 251 and the rear curtain driven arm 261.
Specifically, the substrate-side coupling part 222 of the front
curtain driving arm 221 and the substrate-side coupling part 232 of
the front curtain driven arm 231 are coupled to the substrate 210
below the substrate-side coupling part 252 of the rear curtain
driving arm 251 and the substrate-side coupling part 262 of the
rear curtain driven arm 261 in the figures.
[0036] The front curtain light-shielding blade 220 is a
light-shielding member that extends in the X axis direction and is
pivoted by the front curtain driving arm 221 and the front curtain
driven arm 231 at its right end. In this embodiment, the front
curtain light-shielding blade 220 is made of a single blade.
[0037] The front curtain driving arm 221 has a hole 224, into which
a front curtain driving pin 281 penetrating through an elongated
hole 240 of the substrate 210 is inserted from the depth side of
the paper plane, that is, from the front side of the digital camera
1. The front curtain driving pin 281 is driven by the front curtain
actuator (not shown). The front curtain actuator is driven by a
driving current, that is, power supply from a power supply unit
(not shown) of the controller 26. When the front curtain driving
pin 281 is driven along the elongated hole 240 by the front curtain
actuator, the front curtain driving arm 221 and the front curtain
driven arm 231 rotate about the substrate-side coupling part 222
and the substrate-side coupling part 232, respectively.
[0038] When the front curtain driving arm 221 is rotated about the
substrate-side coupling portion 222, the front curtain
light-shielding blade 220 is driven by the known parallel link
mechanism, which is constituted by the front curtain driving arm
221, the front curtain driven arm 231, and the front curtain
light-shielding blade 220, to move across the opening 215 of the
substrate 210 in the Y axis direction, as described above. In this
embodiment, the front curtain light-shielding blade 220 can move
between the first withdrawn position 201 which is a first position
outside the opening 215 and the second withdrawn position 202 which
is a second position outside the opening 215, the second position
being opposite to the first position (FIG. 2). It should be noted
that the first withdrawn position 201 and the second withdrawn
position 202 are opposite to each other with the opening 215
therebetween, where the first withdrawn position 201 is provided
above the opening 215 in the figures and the second withdrawn
position 202 is provided below the opening 215 in the figures. The
front curtain light-shielding blade 220 has moved to the first
withdrawn position 201 in FIG. 2 and in the second withdrawn
position 202 in FIG. 4. As is apparent from FIGS. 2 to 4, the
distance between the front curtain driven arm 231 and the first
withdrawn position 201 is smaller than the distance between the
front curtain driving arm 221 and the first withdrawn position
201.
[0039] As described above, the front curtain light-shielding blade
220 is made of a single blade. A length (a light-shielding width)
L1 in the Y axis direction (a shift direction of the front curtain
light-shielding blade 220 and the rear curtain light-shielding
blade 250) between an upper edge 220U (FIG. 3) of the front blade
light-shielding blade 220, which is a side extending in the X axis
direction on the negative Y axis side, and a bottom edge 220B (FIG.
3), which is a side extending in the X axis direction on the
positive Y axis side, is shorter (smaller) than the length LO of
the opening 215 in the Y axis direction. The front curtain
light-shielding blade 220 can therefore only partly cover the
opening 215, in terms of structure. In other words, the front
curtain light-shielding blade 220 has a light-shielding range in
its shift direction that is shorter than the length of the opening
215 in the shift direction, in terms of structure.
[0040] Although this embodiment describes the front curtain
light-shielding blade 220 shifting on the rear side (the image
sensor 22 side) of the opening 215, a variation of the embodiment
contemplates the front curtain light-shielding blade 220 shifting
on the front side (the subject side) of the opening 215.
Furthermore, the front curtain light-shielding blade 220 is not
limited to the configuration made of a single blade. Alternatively,
the front curtain light-shielding blade 220 may be constituted by a
plurality of blades and a light-shielding region formed by the
plurality of blades may have a shorter (smaller) length in the Y
axis direction than the length L0 of the opening 215 in the Y axis
direction so as to not entirely cover the opening 215.
[0041] Rear Curtain
[0042] As well illustrated in FIGS. 3 and 4, for example, the rear
curtain driving arm 251 has a substrate-side coupling part 252 in
one end, at which the rear curtain driving arm 251 is rotatably
pivoted by the substrate 210 on the rear side (the image sensor 22
side) of the substrate 210. The rear curtain driven arm 261 has a
substrate-side coupling part 232 in one end, at which the rear
curtain driven arm 261 is rotatably pivoted by the substrate 210 on
the rear side (the image sensor 22 side) of the substrate 210,
below the rear curtain driving arm 251 in the figures. The rear
curtain driving arm 251 has a light-shielding member-side coupling
part 253 at the other end, at which a plurality of rear curtain
light-shielding Hades 250 are rotatably coupled to the rear curtain
driving arm 251 with a caulking pin. The rear curtain driven arm
261 has a light-shielding member-side coupling part 263 at the
other end, at which a plurality of rear curtain light-shielding
blades 250 are rotatably coupled to the rear curtain driven arm 261
with a caulking pin. The rear curtain driving arm 251 and the rear
curtain driven arm 261 constitute a known parallel link mechanism
for moving the rear curtain light-shielding blade 250. It should be
noted that the rear curtain driving arm 251 and the rear curtain
driven arm 261 are provided above the front curtain driving arm 221
and the front curtain driven arm 231.
[0043] The rear curtain light-shielding blade 250 is a
light-shielding member constituted by a plurality of blades
extending in the X axis direction, each blade being pivoted by the
rear curtain driving arm 251 and the rear curtain driven arm 261 at
its right end.
[0044] The rear curtain driving arm 251 has a hole 254, into which
a rear curtain driving pin 282 penetrating through an elongated
hole 270 of the substrate 210 is inserted from the depth side of
the paper plane, that is, from the front side of the digital camera
1. The rear curtain driving pin 282 is driven by the rear curtain
actuator (not shown). The rear curtain actuator is driven by a
driving current or power supply from a power supply unit (not
shown) of the controller 26. When the rear curtain driving pin 282
is driven along the elongated hole 270 by the rear curtain
actuator, the rear curtain driving arm 251 and the rear curtain
driven arm 261 rotate about the substrate-side coupling part 252
and the substrate-side coupling part 262, respectively.
[0045] When the rear curtain driving arm 251 is rotated about the
substrate-side coupling portion 252, the rear curtain
light-shielding blade 250 is driven by the known parallel link
mechanism constituted by the rear curtain driving arm 251, the rear
curtain driven arm 261, and the rear curtain light-shielding blade
250 to move across the opening 215 of the substrate 210 in the Y
axis direction, as described above. In this embodiment, the rear
curtain light-shielding blade 250 can move to the first withdrawn
position 201 and to a light-shielding position Where the rear
curtain light-shielding blade 250 entirely covers the opening 215.
As illustrated in FIGS. 2 to 4, the plurality of blades of the rear
curtain light-shielding blade 250 overlap one another in the first
withdrawn position 201. Although not illustrated, the plurality of
blades of the rear curtain light-shielding blade 250 are unfolded
to shield the opening 215 in the light-shielding position.
[0046] In other words, the front curtain light-shielding blade 220
described above is a primary light-shielding member that partly
shields the opening 215, while the rear curtain light-shielding
blade 250 is a secondary light-shielding member that is arranged to
be movable from the first withdrawn position 201 to the
light-shielding position, independent of the primary
light-shielding member.
[0047] Although this embodiment describes the rear curtain
light-shielding blade 250 shifting on the rear side (the image
sensor 22 side) of the opening 215, a variation of the embodiment
contemplates the rear curtain light-shielding blade 250 shifting on
the front side (the subject side) of the opening 215. Furthermore,
although the rear curtain light-shielding blade 250 entirely
shields the opening 215 in this embodiment, the rear curtain
light-shielding blade 250 may partly shield the opening 215 in the
same manner as the front curtain light-shielding blade 220. In this
case, the rear curtain light-shielding blade 250 may be made of a
single blade or may be constituted by a plurality of blades so as
to not entirely cover the opening 215.
[0048] The Front Curtain Driving Arm 221 and the Front Curtain
Driven Arm 231
[0049] FIGS. 5(a) and 5(b) are views illustrating a state where the
front curtain light-shielding blade 220 is withdrawn in the first
withdrawn position 201, in FIGS. 5(a) and 5(b), the rear curtain
light-shielding blade 250, the rear curtain driving arm 251, and
the rear curtain driven arm 261 are omitted for convenience of
explanation.
[0050] In this embodiment, when the front curtain light-shielding
blade 220 is withdrawn in the first withdrawn position 201 as
illustrated in FIG. 5(a), a straight line La connecting the
substrate-side coupling part 232 and the light-shielding
member-side coupling part 233 of the front curtain driven arm 231
intersects an elongated hole 270 of the substrate 210.
Specifically, the straight line La connecting the substrate-side
coupling part 232 and the light-shielding member-side coupling part
233 of the front curtain driven arm 231 intersects a movement range
of the rear curtain driving pin 282. In other words, the movement
range of the rear curtain driving pin 282 extends between the
substrate-side coupling part 232 and the light-shielding
member-side coupling part 233 of the front curtain driven arm 231
having moved the front curtain light-shielding blade 220 into the
first withdrawn position 201. It should be noted that the movement
range of the rear curtain driving pin 282 is substantially the same
as the range over which the elongated hole 270 extends.
[0051] While the front curtain driven arm 231 moves along the rear
surface of the substrate 210, the rear curtain driving pin 282
penetrating through the elongated hole 270 of the substrate 210
protrudes to the rear side of the substrate 210. If the front
curtain driven arm 231 has a form linearly connecting the
substrate-side coupling part 232 and the light-shielding
member-side coupling part 233, a movement range of the front
curtain driven arm 231 overlaps the movement range of the rear
curtain driving pin 282. In other words, if the front curtain
driven arm 231 is a form linearly extending along the straight line
La, a side surface of an upper side of the front curtain driven arm
231 in the figures is located in a position denoted by a dashed
double-dotted line 291 in FIG. 5(b) in a state where the front
curtain light-shielding blade 220 is withdrawn in the first
withdrawn position 201. Even if the front curtain driven arm 231
has a linear form along the straight line La as described above,
the side surface (corresponding to the dashed double-dotted line
291) of the front curtain driven arm and a side surface of the rear
curtain driving pin 282 cannot collide with each other when the
front curtain light-shielding blade 220 is withdrawn in the first
withdrawn position 201, as long as the rear curtain driving pin 282
remains at the top right of the elongated hole 270. However, if the
rear curtain driving pin 282 moves toward the lower left of the
elongated hole 270 for sonic reason with the front curtain
light-shielding blade 220 being withdrawn in the first withdrawn
position 201, the side surface (corresponding to the dashed
double-dotted line 291) of the front curtain driven arm having a
linear form along the straight line La and the side surface of the
rear curtain driving pin 282 collide with each other, which can
damage the front curtain driven arm.
[0052] As illustrated in FIG. 5(a), the front curtain driven arm
231 in this embodiment is thus curved to be convex toward the front
curtain driving arm 221 so that the front curtain driven arm 231
does not overlap the elongated hole 270, that is, the movement
range of the rear curtain driving pin 282. This curve causes the
curved portion of the front curtain driven arm 231 to partly
overlap the front curtain driving arm 221. For the purpose of
avoiding the interference between the curved portion of the front
curtain driven arm 231 and the front curtain driving arm 221, the
front curtain driven arm 231 is provided with a stepped portion 235
in the vicinity of the substrate-side coupling part 232 and a
stepped portion 236 in the vicinity of the light-shielding
member-side coupling part 233, as explicitly illustrated in FIGS.
5(a) and FIG. 6(a). These stepped portions 235, 236 allow an
intermediate portion 234 of the front curtain driven arm 231
extending between the stepped portions 235, 236 to be arranged at a
distance from the front curtain driving arm 221. This avoids the
interference between the intermediate portion 234 of the front
curtain driven arm 231 and the front curtain driving arm 221.
[0053] It should be noted that any contact between the surface 234a
of the front curtain driven arm 231 and the surface 221a of the
front curtain driving arm 221 or the surface 223a of the
light-shielding member coupling part 223 does not lead to a problem
in operation since the the front curtain driven arm 231 and the
front curtain driving arm 221 or the light-shielding member
coupling part 223 are displaced with respect to each other in the
direction in which they overlap each other. Although a friction
loss may be caused by the contact in this case, the performance of
the shutter can be maintained only by a driving force being changed
in accordance with a change in the friction loss. Additionally, the
durability is not reduced since the surfaces are not in firm
contact with each other.
[0054] As described above, the front curtain driven arm 231 is
curved to be convex toward the front curtain driving arm 221 so as
not to overlap the elongated hole 270. This curve of the front
curtain driven arm 231 forms a recessed region 292, which is
denoted by hatching as illustrated in FIG. 5(b). Instead of or in
addition to the elongated hole 270, other components may be
arranged in the recessed region 292. This enables the shutter
components to be densely arranged and reduces the size of the
shutter device 21.
[0055] It should be noted that the stepped portions 235, 236
described above may be omitted if the curved portion, namely, the
intermediate portion 234 of the front curtain driven arm 231 does
not overlap the front curtain driving arm 221 even though the front
curtain driven arm 231 is curved so as not to overlap the elongated
hole 270. Furthermore, although the front curtain driven arm 231 is
curved to be convex toward the front curtain driving arm 221 in the
above embodiment, the front curtain driven arm 231 may be curved to
be convex in a direction away from the front curtain driving arm
221 so as not to overlap the elongated hole 270, depending on the
relative positional relationship between the front curtain driven
arm 231 and the elongated hole 270.
[0056] In terms of the positional relationship between the opening
215 and the elongated hole 270, in this embodiment, the front
curtain driven arm 231 and the front curtain driving arm 221 are
located between a shorter side edge 215a of the opening 215 and one
end 270a of the elongated hole 270 in the first withdrawn position
201, as illustrated in FIG. 5(a).
[0057] FIGS. 6(b) and 6(c) are schematic side views of the front
curtain driving arm 221 and the front curtain driven arm 231,
illustrating other examples in which the front curtain driving arm
221 and the front curtain driven arm 231 overlap each other in
different manners. As illustrated in FIG. 6(b), for example, the
front curtain driven arm 231 may be displaced toward the rear side
of the front curtain driving arm 221, without the stepped portions
235 and 236 provided in the front curtain driven arm 231. In other
words, the entire front curtain driven arm 231 is displaced with
respect to the front curtain driving arm 221 in the direction in
which the arms overlap each other. In FIG. 6(b), reference numeral
291 denotes a spacer interposed between the front curtain
light-shielding blade 220 and the front curtain driven arm 231.
Such a configuration also achieves the same operational advantage
as in the case where the stepped portions 235, 236 are provided so
that the intermediate portion 234 is displaced with respect to the
front curtain driving arm 221 in the direction in which the
intermediate portion 234 and the front curtain driving arm 221
overlap each other. It should be noted that the spacer 291 may be
integrated with the front curtain driven arm 231, the front curtain
light-shielding blade 220, or the light-shielding member coupling
part 223.
[0058] Alternatively, as illustrated in FIG. 6(c), the front
curtain driving arm 221 may be coupled to the front curtain
light-shielding blade 220 on its front side surface (the subject
side), while the front curtain driven arm 231 may be coupled to the
front curtain light-shielding blade 220 on the rear side surface
(the image sensor 22 side) of the front curtain light-shielding
blade 220. Although not illustrated, the front curtain driving arm
221 may be coupled to the front curtain light-shielding blade 220
on the rear side surface (the image sensor 22 side). While the
front curtain driven arm 231 may be coupled to the front curtain
light-shielding blade 220 on the front side surface (the subject
side) of the front curtain light-shielding blade 220. In other
words, the front curtain driving arm 221 and the front curtain
driven arm 231 may be coupled to the front curtain light-shielding
blade 220 on opposite surfaces of the front curtain light-shielding
blade 220. Such a configuration also achieves the same operational
advantage as in the case where both the front curtain driving arm
221 and the front curtain driven arm 231 are coupled to the front
curtain light-shielding blade 220 on the rear side surface (the
image sensor 22 side) of the front curtain light-shielding blade
220 and the stepped portions 235, 236 are provided so that the
intermediate portion 234 is displaced with respect to the front
curtain driving arm 221 in the direction in which the intermediate
portion 234 and the front curtain driving arm 221 overlap each
other.
[0059] In FIGS. 6(a), (b), and (c) described above, thicknesses of
members and gaps between adjacent members in the horizontal
direction are emphasized for convenience of explanation. As
described above with reference to FIG. 5(a), gaps between members
are not indispensable. The members may partly contact with each
other as long as they are displaced in the direction in which they
overlap each other. Additionally, as illustrated in FIG. 6(a), both
the front curtain driving area 221 and the front curtain driven arm
231 are coupled to the front curtain light-shielding blade 220 on
the rear side surface (the image sensor 22 side) of the front
curtain light-shielding blade 220.
[0060] Operation of the Shutter Device 21
[0061] The shutter device 21 configured as described above operates
as follows. Before the user operates the release button, both the
front curtain light-shielding blade 220 and the rear curtain
light-shielding blade 250 are located in the first withdrawn
position 201 as illustrated in FIG. 2 so that subject light having
passed through the photographic lens 11 is incident onto the image
sensor 22 through the opening 215. Image-capturing signals are
repeatedly read out from the image sensor 22 and images (preview
images) corresponding to the image-capturing signals are displayed
on the rear side monitor 30. This process is referred to as a live
view display.
[0062] When the user operates the release button, the power supply
unit (not shown) of the controller 26 starts to supply an electric
power to the front curtain actuator (not shown) for shifting the
front curtain light-shielding blade 220. When being supplied with
the electric power, the front curtain actuator rotates the front
curtain driving pin 281 along the elongated hole 240 in the
counterclockwise direction in FIG. 2. As a result, the front
curtain driving arm 221 and the front curtain driven arm 231 are
rotated about the substrate-side coupling part 222 and the
substrate-side coupling part 232, respectively, in a plane parallel
to the XY plane so that the front curtain light-shielding blade 220
shifts from the first withdrawn position 201 in the positive Y axis
direction. A bottom edge 220B of the front curtain light-shielding
blade 220 starts to enter the area of the opening 215 and thus
shield the image-capturing plane of the image sensor 22 behind the
shutter. The image sensor 22 resets stored charge (pixel reset) for
pixels in the shielded region, in synchronization with the movement
of the front curtain light-shielding blade 220. When the upper edge
220U of the front curtain light-shielding blade 220 passes through
the region of the image sensor 22 that has been shielded by the
front curtain light-shielding blade 220 as illustrated in FIG. 3,
an exposure is started in the image-capturing plane of the image
sensor 22 to store electric charges for the image-capturing region
and thus its pixels through which the upper edge 200U passes. In
this way, when the upper edge 220U shifts in the positive Y axis
direction beyond the bottom end 215B of the opening 215 so that the
front curtain light-shielding blade 220 moves to the second
withdrawn position 202 (see FIG. 4), the pixel reset and the
exposure (i.e., the charge storage) are performed for the entire
image-capturing plane of the image sensor 22.
[0063] In this context, the controller 26 controls the timing of
pixel reset for each of pixel rows extending in the X axis
direction that constitute the image sensor 22, in accordance with
(in synchronization with) the shift of the front curtain
light-shielding blade 220 in the positive Y axis direction. In
other words, the controller 26 resets pixels in the range shielded
by the front curtain light-shielding blade 220 of the image sensor
22.
[0064] Once a time equivalent to the exposure time has elapsed
since the front curtain light-shielding blade 220 started to shift,
the power control unit (not shown) of the controller 26 supplies an
electric power to the rear curtain actuator (not shown) for
shifting the rear curtain light-shielding blade 250. When the rear
curtain actuator is supplied with the electric power, the rear
curtain actuator rotates the rear curtain driving pin 282 along the
elongated hole 270 in the counterclockwise direction in FIG. 2. As
a result, the rear curtain driving arm 251 and the rear curtain
driven arm 261 are rotated about the substrate-side coupling part
252 and the substrate-side coupling part 262, respectively, in a
plane parallel to the XY plane so that the rear curtain
light-shielding blade 250 shifts from the first withdrawn position
201 in the positive Y axis direction.
[0065] In this way, the front curtain light-shielding blade 220
first starts to shift in the positive Y axis direction and, after a
time equivalent to the exposure time has elapsed, the rear curtain
light-shielding blade 250 then starts to shift in the positive Y
axis direction. Consequently, subject light is incident onto the
image sensor 22 after the reset, only during the exposure time,
from a space between the upper edge 220U (FIG. 3) of the front
curtain light-shielding blade 220 and the lower end of the
lowermost blade of the rear curtain light-shielding blade 250. The
image sensor 22 is exposed with the subject light.
[0066] Thereafter, the rear curtain light-shielding blade 250 moves
to the light-shielding position where it covers the entire opening
215.
[0067] The controller 26 controls the image sensor 22 to start to
sequentially read pixels from the outermost pixel row on the
negative Y axis side. Upon completion of reading the
image-capturing signals from all the pixel rows, the controller 26
outputs driving signals from the power supply unit (not shown) to
cause the front curtain actuator and the rear curtain actuator to
shift the front curtain light-shielding blade 220 and the rear
curtain light-shielding blade 250, respectively, in the negative Y
axis direction. Then, the blades are stored in the first withdrawn
position 201 and the controller 26 ends the operational control for
the shutter device 21 at the photographing.
[0068] In this embodiment, the front curtain light-shielding blade
220 and the rear curtain light-shielding blade 250 are stored in
the first withdrawn position 201 until the photographing starts, as
described above. In contrast to the case where the front curtain
light-shielding blade 220 and the rear curtain light-shielding
blade 250 are stored in positions that are opposite to each other
with the opening 215 therebetween, it is thus not necessary to
shift the front curtain light-shielding blade 220 to a stored
position at the start of the photographing. As a result, a release
time lag is eliminated or minimized.
[0069] If the user operates the release button and then a
malfunction of the power supply unit causes an electric power to be
supplied to the rear curtain actuator before the front curtain
actuator, for example, the rear curtain driving pin 282 rotates in
the counterclockwise direction along the elongated hole 270 from
the state illustrated in FIG. 2 (or FIG. 5(a)) while the front
curtain remains in the state illustrated in FIG. 2 (or FIG. 5(a)).
Nevertheless, the rear curtain driving pin 282 does not interfere
with the front curtain driven arm 234. Additionally, even if a
mechanical shock is applied to the camera in the state of FIG. 2
(or FIG. 5(a)) to cause only the rear curtain to shift, the rear
curtain driving pin 234 and the front curtain driven arm 234 do not
interfere with each other. Resetting the camera from these states
to its initial state and thus returning the shutter to the state
illustrated in FIG. 2 enables an additional photographing to be
performed.
[0070] This embodiment provides the following operational
advantages.
[0071] (1) The shutter device 21 includes: the front curtain
light-shielding blade 220 that can move to the first withdrawn
position 201 and the second withdrawn position 202, the first and
second withdrawn position 201, 202 being opposite to each other
with the opening 215 therebetween; and the front curtain driving
arm 221 and the front curtain driven arm 231 that move the front
curtain light-shielding blade 220. Furthermore, the front curtain
driven arm 231 arranged on the first withdrawn position 201 side is
curved to be convex toward the front curtain driving arm 221. Other
shutter components such as the elongated hole 270 can be arranged
in the space of the curved and recessed portion (the recessed
region 292) formed by the curve of the the front curtain driven arm
231.
[0072] Specifically, it is possible to prevent the interference
between the front curtain driven arm 231 and the rear curtain
driving pin 282. The front curtain light-shielding blade 220 and
the rear curtain light-shielding blade 250 can therefore be stored
in the first withdrawn position 201 until the photographing starts,
so that the release time lag can be eliminated or minimized as
described above.
[0073] (2) The front curtain driven arm 231 is curved so as to
overlap the front curtain driving arm 221. In other words, one of
the arms constituting the parallel link mechanism is curved so as
to overlap the other arm. The recessed region 292 formed by the
curve of the front curtain driven arm 231 can be extended as
compared with the case where the front curtain driven arm 231 and
the front curtain driving arm 221 do not overlap each other. This
extends the space in which other shutter components such as the
elongated hole 270 may be arranged, which can further contribute to
reduce the size of the shutter device 21 and the digital camera 1.
Furthermore, the overlap of the front curtain driven arm 231 and
the front curtain driving arm 221 can prevent elastic deformation
of the arms.
[0074] (3) The curve of the front curtain driven arm 231 made so as
to overlap the front curtain driving arm 221 can avoid an increased
thickness of the shutter device 21 in the optical axis direction,
as compared with the case where the interference between the front
curtain driven arm 231 and the rear curtain driving pin 282 can be
prevented by the curvature of the front curtain driven arm 231 in
the optical axis direction. This can contribute to reduce the size
of the shutter device 21 and the digital camera 1.
[0075] (4) Not the front curtain driving arm 221 which receives the
driving force transmitted from the front curtain driving pin 281,
but the front curtain driven arm 231 is configured to be curved.
This configuration can prevent the interference between the front
curtain driven arm 231 and the rear curtain blade driving pin 282
without affecting the weight and strength of the front curtain
driving arm 221 and thus maintain the performance of the shutter
device 21.
[0076] (5) The front curtain driven arm 231 is provided with the
intermediate portion 234 that overlaps the front curtain driving
arm 221 between the substrate-side coupling part 232 and the
light-shielding member-side coupling part 233. Furthermore, the
stepped portion 235 is provided between the substrate-side coupling
part 232 and the intermediate portion 234 and the stepped portion
236 is provided between the light-shielding member-side coupling
part 233 and the intermediate portion 234, so that the intermediate
portion 234 is displaced with respect to the front curtain driving
arm 221 in the direction in which the intermediate portion 234 and
the front curtain driving arm 221 overlap each other. This can
prevent the interference between the front curtain driving arm 221
and the front curtain driven arm 231 in the intermediate portion
234, without reducing the durability of the shutter device 21.
[0077] (6) The front curtain driven arm 231 is shaped so as not to
overlap the movement range of the rear curtain driving pin 282 even
in a state where the front curtain light-shielding blade 220 has
been moved into the first withdrawn position 201. Consequently, the
front curtain driving arm 221 and the front curtain driven arm 231
do not interfere with the rear curtain driving pin 282 even when
the movement range of the front curtain light-shielding blade 220
is made wider than that in a conventional shutter device. The front
curtain light-shielding blade 220 and the rear curtain
light-shielding blade 250 can therefore be stored in the first
withdrawn position 201 until the photographing starts, so that the
release time lag can be eliminated or minimized as described
above.
[0078] (7) Of the front curtain driving arm 221 and the front
curtain driven arm 231 constituting the parallel link mechanism,
not the front curtain driving arm 221 which transmits the driving
force for moving the front curtain light-shielding blade 220, but
the front curtain driven arm 231 which is driven together with the
front curtain light-shielding blade 220 by the front curtain
driving arm 221 has the shape for avoiding the interference with
the movement range of the rear curtain driving pin 282. This can
maintain the performance of the shutter device 21 without
increasing a transmission loss of the driving force.
[0079] (8) The front curtain driven arm 231 is configured to be
located between the opening 215 and the elongated hole 270 when the
front curtain light-shielding blade 220 is withdrawn in the first
withdrawn position 201. This can extend the movement range of the
front curtain light-shielding blade 220 and prevent the
interference between the front curtain driven UM 231 and the rear
curtain driving pin 282. Additionally, the front curtain driven arm
231 withdraws from the opening 215 while the front curtain
light-shielding blade 220 is withdrawn into the first withdrawn
position 201, so that the front curtain driven arm 231 can have no
influence on the live view display.
[0080] (9) The front curtain light-shielding blade 220 can move to
the first withdrawn position 201 and the second withdrawn position
202, and the movement ranges of the front curtain driven arm 231
and the rear curtain driving pin 282 do not overlap each other.
Consequently, the front curtain driven arm 231 does not interfere
with the rear curtain driving pin 282 even when the movement range
of the front curtain light-shielding blade 220 is made wider than
that in a conventional shutter device. The front curtain
light-shielding blade 220 and the rear curtain light-shielding
blade 250 can therefore be stored in the first withdrawn position
201 until the photographing starts, so that the release time lag
can be eliminated or minimized as described above.
[0081] Variations
[0082] (1) In the above description, the front curtain driven arm
231 is curved to be convex toward the front curtain driving arm
221. Alternatively, the front curtain driving arm 221 may be curved
to be convex toward the front curtain driven arm 231. For example,
the front curtain driving arm 221 may be curved to be convex toward
the front curtain driven arm 231 if the front curtain driving arm
221 is provided above the front curtain driven arm 231 in the
figures and is closer to the rear curtain driving pin 282 than the
front curtain driven arm 231, which can cause the interference
between the front curtain driving arm 221 and the rear curtain
driving pin 282.
[0083] (2) In the above description, the configuration for
preventing the interference between the rear curtain driving pin
282 and the front curtain driven arm 231 has been described.
However, the rear curtain driving arm 251 or the rear curtain
driven arms 261 may be curved if the rear curtain driving arm 251
or the rear curtain driven arm 261 can interfere with the members
for driving the front curtain light-shielding blade 220.
[0084] (3) In the above description, the front curtain driving arm
221 and the front curtain driven arm 231 are configured so as to
overlap in the optical axis direction of the subject light.
However, the overlap of the front curtain driving arm 221 and the
front curtain driven arm 231 is not indispensable. The front
curtain driving arm 221 and the front curtain driven arm 231 may
not overlap each other.
[0085] (4) In the above description, the front curtain driven arm
231 is provided with the stepped portions 235, 236. Alternatively,
the front curtain driving arm 221 may be provided with stepped
portions equivalent to the stepped portions 235, 236.
[0086] (5) The shape of the front curtain driven arm 231 in the
above description is merely exemplary, and other implementations as
illustrated in FIG. 7 may be employed. FIG. 7 is a view
schematically illustrating other implementations of the front
curtain driven arm 231. For example, the front curtain driven arm
231A may be bent into a U-shape, as schematically illustrated in
FIG. 7(a). Alternatively, the front curtain driven arm 231B may
have a wide form and be bent with a cutout 231a so as to extend
around the elongated hole 270 of the substrate 210, as
schematically illustrated in FIG. 7(b).
[0087] (6) In the above description, the front curtain actuator is
made of an electric motor or the like. Alternatively, the front
curtain actuator may be configured to shift the front curtain
light-shielding blade 220 toward the second withdrawn position 202
by a biasing force of a spring and to urge the front curtain
light-shielding blade 220 into the first withdrawn position 201 by
a power of the electric motor. The same also applies to the rear
curtain actuator. Furthermore, the front curtain actuator may be
made of an electric motor or the like, while the rear curtain
actuator may be constituted by a spring and an electric motor.
Still further, the front curtain actuator may be constituted by a
spring and an electric motor, while the rear curtain actuator may
be made of an electric motor or the like.
[0088] (7) In the above description, the first withdrawn position
201 is provided above the opening 215 on the figures and the second
withdrawn position 202 is provided below the opening 215 on the
figures. Alternatively, the first withdrawn position 201 may be
provided below the opening 215 and the second withdrawn position
202 may be provided above the opening 215 on the figures. If the
front curtain light-shielding blade 220 and the rear curtain
light-shielding blade 250 are configured to move across the opening
215 in the X axis direction, the first withdrawn position 201 may
be provided on either the right or left side of the opening 215 on
the figures and the second withdrawn position 202 may be provided
on the other side of the opening 215.
[0089] (8) The above-described embodiment and variations may be
combined.
[0090] The disclosure of the following priority application is
herein incorporated by reference:
[0091] Japanese Patent Application No. 2014-223428 (filed Oct. 31,
2014)
REFERENCE SIGNS LIST
[0092] 1 . . . digital camera, 21 . . . shutter device, 22 . . .
image sensor, 210 . . . substrate, 215 . . . opening, 220 . . .
front curtain light-shielding blade, 221 . . . . front curtain
driving arm, 222 . . . substrate-side coupling part, 223 . . . .
shielding member-side coupling part, 231 . . . front curtain driven
arm, 232 . . . substrate-side coupling part, 233 . . . shielding
member-side coupling part, 234 . . . intermediate portion, 235, 236
. . . stepped portion, 240, 270 . . . elongated hole, 250 . . .
rear curtain light-shielding blade, 251 . . . rear curtain driving
arm, 261 . . . rear curtain driven arm, 281 . . . front curtain
driving pin, 282 . . . rear curtain driving pin
* * * * *