JP2002341400A - Focal plane shutter for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a focal plane shutter for a camera which can suppress the amount of abrasion powder produced by the operation of shutter blades and sticked on an image pickup surface. SOLUTION: A blade chamber for a first blade is formed between a shutter base plate 1 and an intermediate plate 4 and a blade chamber for a second blade is formed between the intermediate plate 4 and an auxiliary base plate 5. Two arms for the first blade and second blade never enter an exposure opening during operation. Connecting shafts interposed between the arms and blades never abut against the edges of opening parts 1a and 5a for exposure or their vicinities to produce no abrasion powder. The auxiliary base plate 5 has a wall 5f formed on the blade chamber side, so it is made hard for abrasion powder produced by the operation of the second blade to scatter from the blade chamber and the sticking of the abrasion powder on the image pickup is made extremely small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focal plane shutter for a camera.

[0002]

2. Description of the Related Art A focal plane shutter includes two shutter blades (a front blade (group) and a rear blade (group)), which are called a shutter base plate, an intermediate plate, and an auxiliary base plate. There are some which are separately arranged in two blade chambers constituted by three plate members. This type is also used in film-based cameras and digital cameras. When shooting, two shutter blades are sequentially activated at a predetermined time interval, and a rectangle is formed by a slit formed by them. The exposure is performed continuously from one side of the imaging surface to the opposite side.

[0003] Some focal plane shutters used in digital cameras have only one shutter blade. In such a case, one blade chamber is formed by the shutter base plate and the auxiliary base plate. Make up. In this type, the imaging surface is usually exposed to subject light so that the imaging surface is temporarily covered only at the end of shooting.

However, in either case, the structure of each shutter blade is the same, and one or more strip-shaped arms are attached to a plurality of arms each having one end pivotally connected to a shutter base plate. By pivoting the blades, the mechanism is configured as a mechanism applying a parallelogram link mechanism. Further, the pivotal configuration of each arm and the blade is such that holes formed in the arm and the blade are overlapped, and the tip of a connection shaft, which is a rivet component, is inserted into the hole from the arm side and swaged to the blade. . And the caulking part is prevented from protruding from the sliding surface of the blade due to the shape of the blade,
The head of the connecting shaft is located on the shutter base plate or auxiliary base plate side, and protrudes from the arm. The present invention relates to a focal plane shutter for a camera having such a configuration.

[0005]

By the way, the shutter blade constructed as described above apparently operates on a predetermined plane regularly and stops as if it were stopped without any problem. Although it can be seen, in practice, it sometimes operates with a complicated movement in a direction different from the operation direction, and when stopped, it receives a strong impact, and the arms and blades are greatly deformed. Therefore, when such an operation is repeated, the blade chambers slide, for example, between members constituting the shutter blades, and between the head of the connection shaft and the shutter base plate. Due to the sliding or the like of the member constituting the shutter blade with respect to the plate member constituting the above, extremely fine wear powder is generated.

This will be described with reference to the case of the conventional example shown in FIG. FIG. 9 is a plan view as viewed from the subject side, and an opening Aa is formed substantially at the center of the shutter base plate A. Further, this conventional example has two shutter blades, but FIG. 9 shows only the rear blade among them. Therefore, in this conventional example, an intermediate plate B is disposed on the back side of the shutter base plate A, and an auxiliary base plate C is further disposed on the back side, similarly to the embodiment described later. , Are arranged in a blade chamber formed between the intermediate plate B and the auxiliary base plate C. The intermediate plate B and the auxiliary base plate C also have openings B having shapes similar to the openings Aa.
a and Ca are formed, and the shape (image frame) of the exposure opening is regulated by one or more of them.

[0007] The rear wing has two arms D, E and 4
The arms D and E are rotatably mounted on the shutter base plate A at their left ends, and the blades F, G, H and I are Arms D and E are pivotally supported via connecting shafts (rivet parts). Since the pivotal configuration of each blade is the same, only the pivotal configuration of the blade I will be described. The connecting shaft J is inserted from the auxiliary base plate C side into the hole of the arm D and the hole of the blade I. The end is swaged to the blade I. Also,
The connecting shaft K is also inserted into the hole of the arm E and the hole of the blade I from the auxiliary base plate C side, and the inserted end is swaged to the blade I.
Therefore, the heads of the connecting shafts J and K are on the auxiliary base plate C side, and the arms D and E and the connecting shafts J and K are not fixed. Although not explicitly shown in the drawing, the connecting shaft J,
The caulking portion of K is configured to partially protrude from the blade I so that it does not protrude toward the front surface side of the blade I (on the front side in FIG. 9).

In such a configuration, when the rear blade is operated, the operation trajectory of the connecting shafts J and K takes an arc shape as shown by a dashed line. In addition, since the other six connecting shafts are also operated at the same angle, their operating trajectories also have an arc shape. In this operation, the blades F, G,
Since H and I can change the overlapping relationship, sliding is performed between adjacent blades. Further, each of the blades F, G, H, and I also slides on the intermediate plate B and the auxiliary base plate C. On the other hand, the connecting shafts slide between the holes of the arms D and E, and the outer surfaces of their heads slide with respect to the auxiliary base plate C. In most cases, the heads of the connecting shafts J and K temporarily contact the edge of the opening Ca or a position in the vicinity thereof during the operation thereof. Therefore, the sliding and the contact thereof cause the generation of wear dust. Needless to say, this also applies to the case of the leading blade disposed between the shutter base plate A and the intermediate plate B.

By the way, the above-mentioned arm or blade is
Usually, it is manufactured by punching a thin metallic plate material having relatively excellent rigidity with a press machine. Further, the connecting shaft as a rivet component is manufactured by cutting a bar of free-cutting steel. Therefore, even when the shutter blades are configured by a plurality of blades, the degree of the generation of wear powder due to the sliding of the blades is extremely small, and the blades are in contact with the plate member forming the blade chamber. Even if sliding, the sliding contact between the relatively large surface and the surface, even if the plate member is made of synthetic resin (the shutter base plate and the auxiliary base plate may be made of synthetic resin), Generation of wear powder is extremely low.

[0010] However, at the fitting portion between the connecting shaft and the arm, the connecting shaft may be shaved to generate a relatively large amount of wear powder. In addition, when the shutter base plate and the auxiliary base plate are made of metal, relatively hard metal is used. Therefore, the head of the connecting shaft is shaved by sliding or abutting against the metal, so that a relatively large amount of wear powder is generated. It can be done. Further, when the shutter base plate and the auxiliary base plate are made of synthetic resin, abrasion powder may be generated from those base plates.

In this way, even if the abrasion powder is generated, a means is taken so that the abrasion powder moves in a direction away from the exposure opening, and the abrasion powder flies from the exposure opening onto an image forming surface such as a film or a CCD. Unless you try to avoid it, it's hard to find such a convenient solution. In particular,
As described above, the connecting shafts J, K at the forefront of the arms D, E
Operates within the exposure aperture, so that at least the connecting axes J, K
Abrasion powder generated by the presence of
It is very difficult to prevent the particles from adhering to the surface of the device.

[0012] Then, such abrasion powder causes film or C
If it adheres to a surface of a CD or the like in a predetermined amount or more, it becomes impossible to obtain a suitable photographing result, and when the image is enlarged and reproduced, the defect becomes apparent in a part of the image. In particular, in the case of a digital camera, since the image sensor is fixed in the camera, the wear powder directly adheres to the incident surface of the image sensor or adheres to the incident surface of the low-pass filter disposed in front of the image sensor. Doing so will have an effect on all subsequent photographing, and since then, other wear particles will adhere to and on top of it one after another, which is extremely problematic.

Therefore, when such a phenomenon occurs, conventionally, the lens is removed, the mirror is brought up, and further, the shutter blade is moved away from the front surface of the image sensor (the exposure aperture is fully opened). In such a case, the wear powder had to be removed by an air brush or the like. However, such a task is by no means easy, and even for cameras that do not intend to change lenses, such as a camera with a zoom lens, it can even be performed in the above-described manner. Did not. Therefore, the appearance of a focal plane shutter which is less likely to be affected by such abrasion powder is desired.

On the other hand, in the case of a camera using a film, even if the abrasion powder adheres to the film in such a manner, the film is sent each time a picture is taken. It is not possible to accumulate and adhere as in the case. For this reason, in the past, such abrasion powder was not so much a problem, but recently, since it has been regarded as a problem in the case of a digital camera, such a phenomenon is unlikely to occur even if the degree of influence is small. There has been a demand for a shutter.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a first object of the present invention is to provide a connecting shaft interposed at a pivotal support portion between an arm of a shutter blade and the blade. An object of the present invention is to provide a focal plane shutter for a camera in which abrasion powder is not generated by abutting on an edge of an opening of a base plate constituting a chamber or a portion in the vicinity thereof. A second object of the present invention is to provide a focal plane shutter for a camera having a configuration in which abrasion powder generated by the operation of the shutter blades is hard to fly from the exposure aperture toward the image forming surface. is there. Further, the third purpose is:
An object of the present invention is to provide a focal plane shutter for a camera on which the size in the optical axis direction in the camera can be suitably reduced.

[0016]

In order to achieve the above object, a focal plane shutter for a camera according to the present invention comprises:
Either one blade chamber is formed between two ground plates having an opening for exposure at a substantially central portion, or the intermediate plate has an opening for exposure at a substantially central portion. Two blade chambers are formed to partition between the ground plates, and shutter blades disposed in the blade chambers are pivotally connected at one end to one of the ground plates at a position lateral to each of the openings. , And one or more blades pivotally supported by the connecting shafts, so that the operating trajectories of the connecting shafts do not enter the openings of the main plate. .

In the focal plane shutter for a camera according to the present invention, at least one of the two base plates has the opening between the opening formed in the base plate and the operating area of the arm. If the wall is formed so as to protrude toward the blade chamber along the edge of the portion, the wear dust generated by the operation of the shutter blade will not easily fly toward the imaging surface.

In the focal plane shutter for a camera according to the present invention, when the wall is formed so as to extend to the outer edge of the base plate, the abrasion powder is less likely to fly toward the imaging surface. Become.

Further, in the focal plane shutter for a camera according to the present invention, the wall is formed on a main plate arranged on the imaging surface side, and the wall forms an inclined surface facing the subject. Then, the light reflected by the wall hardly reaches the imaging surface. In this case, by forming the inclined surface, the dimension of the end surface of the opening in the direction parallel to the optical axis is made smaller than the thickness of the ground plate on which the inclined surface is formed. Be effective.

In the focal plane shutter for a camera according to the present invention, it is easy to manufacture the wall if the wall is formed by integral molding of a synthetic resin or by projecting and crushing a metal plate.

In the focal plane shutter for a camera according to the present invention, the intermediate plate partitions between the two ground plates and is attached so as not to move relative to the two ground plates. In this case, the function of the wall is more effective than when the wall is mounted.

Further, in the focal plane shutter for a camera according to the present invention, the shutter blade has a plurality of blades, and the wall formed on the blade chamber side of the shutter blade expands the shutter blade. If the projection is formed so as to increase in the operating direction, even when the shutter is downsized, it becomes difficult for the wear dust to fly to the imaging surface.

In the focal plane shutter for a camera according to the present invention, if an adhesive is applied or stuck to the surface of the wall on the side of the operating area of the arm, abrasion powder adheres to the surface and does not scatter. Become like In this case, if the pressure-sensitive adhesive is also an anti-reflection material, it is advantageous in preventing light leakage.

Further, in the focal plane shutter for a camera according to the present invention, the base plate disposed on the imaging surface side is provided with a low-pass filter or a part of the imaging device so as to surround the opening on the surface on the imaging surface side. Forming a concave portion for receiving is advantageous in reducing the thickness of the digital camera.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to three examples. Each of the embodiments is configured as a focal plane shutter for a digital camera. FIGS. 1 to 6 show a first embodiment, FIG. 7 shows a second embodiment, and FIG. This shows three examples. Note that the same reference numerals are given to the same members and portions in each embodiment, and the overlapping description thereof will be omitted. In the drawings of each embodiment, the front blade and the rear blade are shown, but each driving member for driving them, a set member for setting those driving members after photographing, and an exposure of each driving member are set. Each of the electromagnets and the like for controlling the start of operation is not shown in the figure because a well-known configuration is applied and has no direct relation to understanding the present invention.

[First Embodiment] A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of the present embodiment viewed from the subject side (that is, the lens side), and shows a state immediately before the start of the exposure operation. FIG. FIG. 2 is a cross-sectional view showing the configuration of FIG. FIG. 3 is a plan view showing individual blocks of the main constituent blocks shown in FIG. 1 excluding the auxiliary base plate as viewed from the subject side, and FIG. 4 is a view showing the auxiliary base plate as viewed from the subject side. FIG. Further, FIG. 5 is a plan view of the present embodiment viewed from the image sensor side, in which the rear blade is shown in a state immediately after the end of the exposure operation, and FIG. 6 is a state just after the end of the exposure operation in the first embodiment. FIG. 2 is a perspective view viewed in the same manner as FIG.

First, the configuration of the present embodiment will be described. In the description, the subject side is referred to as the front side and the image pickup device side is referred to as the back side in a state where the shutter is mounted on the camera. The shutter base plate 1 disposed closest to the subject in FIG. 1 is made of synthetic resin,
As shown in (a), an opening 1a for exposure is formed substantially at the center, and three arc-shaped long holes 1b, 1c, 1d are formed at the left side of the opening 1a. Have been.
As is well known, butyl rubber cushioning members 2 and 3 having a substantially C-shaped plane are attached to the upper ends of the long holes 1b and 1c.

On the front side of the shutter base plate 1, shafts 1e, 1
f, 1g are erected, of which the shafts 1e, 1
f also protrudes from the back side of the shutter base plate 1, and pivotally attaches (rotatably attaches) arms of a front blade and a rear blade described below. On the front side of the shutter base plate 1, well-known leading blade driving members and rear blade driving members (not shown) are rotatably attached to these shafts 1e and 1f, and are provided on these shafts. Drive pins
It protrudes to the back side through the long holes 1b and 1c. When the exposure operation is completed, the drive pins are brought into contact with the buffer members 2 and 3 and stopped. Further, a well-known set member (not shown) is rotatably attached to the shaft 1g. When the set member is set, the set member rotates from an initial position, and each of the above-mentioned drive members opposes the urging force of each drive spring. Rotate to the set position,
When the pin returns to the initial position, a pin (not shown) comes into contact with one end of the long hole 1d and is stopped.

On the back side of the shutter base plate 1, a shaft 1
The shafts 1h, 1i, 1j, 1k, and 1m are provided upright. Of these shafts, the shafts 1h and 1i are used to pivotally connect the arms of the leading blade and the trailing blade, which will be described later. , 1
m is for attaching an intermediate plate and an auxiliary base plate described later. Furthermore, holes 1n, 1p,
Although 1q is formed, these are provided for attachment to the camera body.

In the above description, the shutter base plate 1 itself and well-known members (not shown) attached mainly to the front surface side of the shutter base plate 1 have been described, and thereafter, the members attached to the back side of the shutter base plate 1 First, an outline of the entire configuration on the back side will be described. On the back side of the shutter base plate 1,
Each of the intermediate plates 4 is spaced at a predetermined interval (see FIG. 3C).
And an auxiliary base plate 5 (see FIG. 4), the space between the shutter base plate 1 and the intermediate plate 4 becomes a blade chamber of the leading blade (see FIG. 3B), and the space between the intermediate plate 4 and the auxiliary base plate 5 Represents a blade chamber of the rear blade (see FIG. 3D). The intermediate plate 4 and the auxiliary base plate 5 are also formed with openings 4a and 5a at substantially the center, and usually, the opening 1a of the shutter base plate 1 is formed.
Are overlapped with each other to form an exposure opening having a horizontally elongated rectangle. In the case of this embodiment, however, the exposure opening is regulated only by the opening 1a. .

Therefore, the front blade shown in FIG. 3B will be described first. The leading blade of the present embodiment is composed of two arms 6, 7 and four blades 8, 9, 10, 11 pivotally supported in the longitudinal direction thereof. 11 is a slit forming blade. And
The arm 6 is pivotally mounted by fitting a hole at the left end thereof to the shaft 1e protruding to the rear side of the shutter base plate 1, and a driving member for the leading blade (not shown) is inserted into the long hole 6a. Drive pins are fitted. Also another arm 7
Again, the hole at the left end is inserted into the shaft 1 of the shutter base plate 1.
h.

As is well known, the pivotal support of each blade with respect to the arms 6 and 7 is performed by using a connecting shaft which is a rivet component, and their pivotal configurations are all the same. Therefore, FIG.
In (b), reference numerals 12 and 13 are attached only to the connecting shaft used for the slit forming blade 11. Among them, the case of a pivotal configuration using the connecting shaft 12 will be described.
The holes formed in the arm 6 and the blade 11 are aligned, the connecting shaft 12 is inserted from the arm 6 side, and the inserted end is inserted into the blade 1.
1, but the arm 6 and the connecting shaft 12 are not fixed. Therefore, in the case of the front blade, all the heads of the eight connecting shafts protrude from the surfaces of the arms 6 and 7 toward the shutter base plate 1 and slide with respect to the shutter base plate 1. I have.

Next, the intermediate plate 4 will be described with reference to FIG. As described above, the intermediate plate 4 has the blade chamber of the front blade formed between the intermediate plate 4 and the shutter base plate 1, and the opening 4a is formed substantially at the center thereof. The opening 4a has a different shape from the opening 1a of the shutter base plate 1,
The reason for this is well known and will not be described. In the present embodiment, the left edge of the opening 4a is
The opening 1a is disposed so as to substantially overlap with the left edge of the opening 1a. The intermediate plate 4 has three holes 4b, 4c, 4
d is fitted and attached to the shafts 1j, 1k, 1m of the shutter base plate 1, but the intermediate plate 4 of the present embodiment is provided with a shaft 1j, 1
It is attached so as not to move in the axial direction of k, 1 m.

A rear blade as shown in FIG. 3D is arranged on the back side of the intermediate plate 4. This rear blade has a configuration in which the above-mentioned front blade is turned upside down, and has two arms 14 and 15 and four blades 16, 17, 18, and 18 pivotally supported in the longitudinal direction thereof in order. 19, the blade 19 pivotally supported at the forefront is a slit forming blade. The arm 14 is pivotally mounted by fitting the hole at the left end of the arm 14 to the shaft 1f protruding to the rear side of the shutter base plate 1, and the elongated hole 14a is provided for the rear blade (not shown). The drive pin of the drive member is fitted. The other arm 15 is pivotally mounted by fitting a hole at the left end thereof to the shaft 1i of the shutter base plate 1.

Each blade 16, 1 for the arms 14, 15
The pivotal arrangement of 7, 18 and 19 is exactly the same as in the case of the leading blade. Therefore, in the case of this rear blade, the arms 14,
15 is disposed closer to the auxiliary base plate 5 than the blades 16, 17, 18, 19, the heads of the eight connecting shafts are all
It protrudes from the surfaces of the arms 14 and 15 toward the auxiliary base plate 5 and slides with respect to the auxiliary base plate 5.
Note that, in the state shown in FIG.
17, 18, and 19 are superimposed and stored at a position below the opening 1 a, but in FIG. 3D, the configuration is shown in an expanded state for easy understanding.

FIG. 4 shows an auxiliary base plate 5 which forms the blade chamber of the rear blade together with the intermediate plate 4. The auxiliary base plate 5 is made of a synthetic resin, and has the opening 5a already described in a substantially central portion. And this opening 5
a has a shape slightly larger than the opening 1 a of the shutter base plate 1, and the left edge formed by the openings 1 a, 4.
It is arranged so as to substantially overlap with the left forming edge of a. On the left side of the opening 5a, four holes are formed, which are holes for receiving the tips of the four shafts 1e, 1f, 1h, 1i provided upright on the shutter base plate 1. is there. Furthermore, holes 5b, 5 are provided at three corners of the auxiliary base plate 5.
c, 5d are formed, but these holes are
Is mounted on the shafts 1j, 1k, and 1m of the shutter base plate 1, and a specific mounting method thereof will be described later.

A light shielding wall 5e is formed on the auxiliary base plate 5 so as to surround most of the outer periphery thereof. The light shielding wall 5e is used to block light from the outer peripheral direction from entering the blade chamber. Things. Further, the auxiliary base plate 5 has a wall 5f extending along the left edge of the opening 5a and extending to the upper and lower outer edges of the auxiliary base plate 5. As can be seen from FIG. 2, an inclined surface 5g is formed on the wall 5f toward the subject side and toward the opening 1a, so that the end face 5h of the opening 5a has its optical axis. Is smaller than the thickness of the auxiliary base plate 5. In the case of the present embodiment, such a wall 5f is formed by an integral molding process using a synthetic resin material. However, when the auxiliary base plate 5 is made of metal, it is advantageous in terms of cost if it is formed by a projection process and a crushing process. It is. And
As can be seen from FIGS. 2 and 5, a recess 5i is formed on the back side of the auxiliary base plate 5 so as to surround the opening 5a.

Next, a method of attaching the auxiliary base plate 5 will be described. Since the attaching method is conventionally known, the method will be briefly described. That is, the axis 1j of the shutter base plate 1
A screw hole is formed in the tip surface of the shaft 1k, and an annular groove is formed around the tip of the shafts 1k and 1m. The holes 5c and 5d of the auxiliary base plate 5 are shaped so that the keyholes are located sideways. Therefore, first, the large openings on the left side of the holes 5c and 5d in FIG. 4 are fitted to the shafts 1k and 1m, and then the auxiliary base plate 5 is moved to the left side to remove the edge of the small opening on the right side. Into the above-mentioned annular groove. Then, in this state, the screw 20 shown in FIG. 5 is passed through the hole 5b and screwed into the screw hole of the shaft 1j.

The shutter unit of this embodiment is constructed as described above, but this shutter is a focal plane shutter for a digital camera. For this reason, an image sensor is arranged on the back side of the auxiliary base plate 5, but as shown in FIG.
, And a low-pass filter 22 is disposed on the front surface thereof. And the above-mentioned concave part 5i of the auxiliary base plate 5
For receiving the low-pass filter 22,
Such a configuration contributes to space saving in the direction along the optical axis in the camera, and also contributes to thinning of the camera. In the present embodiment, the CCD 21 and the low-pass filter 22 are provided separately, but they may be integrated, or there may be a case where the low-pass filter 22 is not provided. Therefore, in the latter case, the concave portion 5i receives the CCD 21.

Next, the operation of this embodiment will be described. FIG.
Indicates a set state of the shutter. At this time, the well-known leading blade drive member and the rear blade drive member (not shown) resist the urging force of the respective drive springs, and are turned clockwise by a set member (not shown) rotated from the initial position. It is in a rotated state. Therefore, the drive pins provided on each drive member rotate the arm 6 of the front blade and the arm 14 of the rear blade clockwise, and the four blades 8, 9, and 10 and 11 are in the unfolded state and cover the opening 1a, and the four blades 16, 17, 18, and 19 of the rear blade are in the superimposed state and the opening 1a.
a.

When the release button of the camera is pressed in such a setting state, first, the electromagnet for the front blade and the electromagnet for the rear blade (not shown) are energized, and the driving member for the front blade and the driving member for the rear blade are turned on. After being sucked and held, the set member returns to the initial position. Then, when the energization of the electromagnet for the front blade is cut off, the holding force of the electromagnet is lost, and the driving member for the front blade rotates counterclockwise by the urging force of the driving spring for the front blade. Therefore, the drive pin of the leading blade drive member rotates the arm 6 in the counterclockwise direction, and operates the four leading blades 8, 9, 10, 11 upward. As a result, the respective blades increase the amount of overlap with each other, and the opening 1a is opened by the slit forming edge, which is the lower edge of the slit forming blade 11. When the slit forming edge of the slit forming blade 11 fully opens the opening 1a, the driving pin of the driving member for the front blade comes into contact with the buffer member 2 and the operation of the driving member for the front blade and the operation of the front blade stop. I do.

In the case of this embodiment, since the tips of the arms 6 and 7 do not pass through the opening 1a during the operation performed in this manner, the connecting shafts 12 and 13 are of course
Does not pass through the opening 1a. Therefore, connecting shaft 1
Since the heads 2 and 13 do not abut against the end surface of the edge of the opening 1a or abut on the blade chamber-side surface of the shutter base plate 1 in the vicinity thereof, as in the related art. Abrasion powder does not occur due to the proper contact. During this operation, abrasion dust may be generated between the arms 6 and 7 and the eight connecting shafts and between the heads of the eight connecting shafts and the surface of the shutter base plate 1 on the blade chamber side. However, since the abrasion powder is generated on the left side of the opening 1a and mainly generated on the object side of each of the blades 8, 9, 10, and 11, the amount of the flying powder that comes to the surface of the low-pass filter 22 is small. , Less than in the case of the rear blade described later.

When a predetermined time elapses after the energization of the electromagnet for the leading blade is cut off, the energization of the electromagnet for the rear blade is cut off. As described above, the timing at which the energization of the rear blade electromagnet is cut off varies depending on the shooting conditions, as is well known.
In many cases, the power is cut off before the exposure operation of the front blade is completed.However, in the description of the operation of the present embodiment, for the sake of explanation, the power supply is stopped after the exposure operation of the front blade is completed as described above. A description will be given in the case of a drip.

When the energization to the electromagnet for the rear blade is cut off, the driving member for the rear blade is rotated counterclockwise by the urging force of the driving spring for the rear blade. Therefore, the driving pin of the driving member for the rear blade rotates the arm 14 in the counterclockwise direction and operates the four blades 16, 17, 18, and 19 of the rear blade upward, so that the respective blades are mutually connected. The overlapping amount is reduced, and the opening 1a is closed by the slit forming edge which is the upper edge of the slit forming blade 19.
When the slit forming edge of the slit forming blade 19 closes the opening 1a, the driving pin of the driving member for the rear blade comes into contact with the buffer member 3, and the operation of the driving member for the rear blade and the rear blade stops. . The stopped state is shown in FIGS.

During the exposure operation of the rear blade,
The operation of the arms 14 and 15 is controlled by the wall 5 formed on the auxiliary base plate 5.
Performed on the left side of f. Therefore, since their tips do not pass through the opening 5a, it goes without saying that the two connecting shafts used in the pivotal configuration of the slit forming blade also do not pass through the opening 5a. Therefore, the heads of these connecting shafts do not abut against the end surface of the edge of the opening 5a, and do not abut against the surface of the auxiliary base plate 5 on the blade chamber side in the vicinity thereof. Such contact does not cause abrasion powder.

Also, during this operation, the arms 14,
In some cases, wear dust may be generated between the connection shaft 15 and the eight connection shafts and between the heads of the eight connection shafts and the surface of the auxiliary base plate 5 on the blade chamber side. Most of the wall 5f
, And the amount flying to the surface of the low-pass filter 22 is small. As you can see from this,
The wall 5f is for preventing the abrasion powder from traveling toward the low-pass filter 22.
In some cases, it is sufficient to form only the edge of the opening 5a. However, in the case of the present embodiment, the auxiliary base plate 5 is extended to the outer peripheral edge in order to more effectively prevent its progress.

The height (dimension protruding toward the blade chamber) of the wall 5f in this embodiment is uniform. Also, even though the intermediate plate 4 and the auxiliary base plate 5 are locally different from each other, the same interval is obtained as a whole,
Fixed to each other. The interval is determined by the thickness of the four rear blades 16, 17, 18, and 19 when they are superposed, the thickness of the arms 14, 15, and the height of the connecting shaft (projecting toward the auxiliary base plate 5 side). Is determined in consideration of the above. Therefore, in the superimposed state, the slit forming blade 19 and the wall 5f are almost in contact with each other.

However, the blades 16, 17, 18, 1
9 is in the unfolded state, the above-mentioned interval is only required to be equal to the thickness of the two adjacent blades.
When approaching to the side, a gap is clearly formed between the slit forming blade 19 and the wall 5f as compared with the overlapping state. Such a gap gradually increases from the superimposed state to the developed state. Therefore,
If there is a demand to block the wear dust flying to the low-pass filter 22 from such a gap, in FIG. 4, the height of the wall 5f may be formed so as to increase as it goes upward. .

Further, conventionally, there has been known a configuration in which the intermediate plate 4 is not fixed to the shafts 1j, 1k, and 1m of the shutter base plate 1. Although the reason is well known, the description is omitted. However, even with such a configuration, if the wall 5f is provided as in the present embodiment, it is possible to suppress the wear powder from coming to the low-pass filter 22. is there. However, if the intermediate plate 4 is not fixed in such a manner, the intermediate plate 4 is moved irregularly in the axial direction of each axis during the operation of the leading blade and the trailing blade. May increase instantaneously. In addition, the movement may cause wear and tear to soar. Therefore, from the standpoint of preventing wear dust from coming into the low-pass filter 22, it is preferable that the intermediate plate 4 is fixed as in this embodiment, regardless of the number of blades.

Further, in this embodiment, an inclined surface 5g is formed on the wall 5f, and the end surface 5 of the opening 5a connected thereto is formed.
h is formed such that the dimension in the direction along the optical axis is smaller than the thickness of the auxiliary base plate 5. Therefore, the reason will be described. In the case of the present embodiment, the surface of the wall 5f on the opening 5a side also serves as an end surface of the opening 5a in order to minimize the left and right dimensions of the shutter. Therefore, if the wall 5f has a simple shape, the area of the end face becomes large, and the light reflected on the end face during photographing and incident on the periphery of the CCD 21 via the low-pass filter 22 increases. In the case of the embodiment, most of the light is reflected on the inclined surface 5g toward the subject.

Further, even when the exposure opening is closed, it is known that reflection is superimposed on a small gap between the components of the shutter, and extremely weak light enters the rear side of the shutter blade. I have. Therefore, if the camera is left in such a state for a long time, weak light may accumulate and deteriorate the performance of the image sensor and the like.
In addition, when applied to a camera using a film, the film is exposed to light, and the next photographing may fail. Therefore, it is necessary to reflect as much as possible even the weak light that has entered as described above and to attenuate the light reaching the imaging surface as much as possible. In this embodiment, however, the end face 5h Is made small and the inclined surface 5g is formed, so that it is possible even a little. However, the wall of the present invention is not limited to such a shape, and may have a simple shape or may be formed at a position slightly away from the edge of the opening 5a.

Next, the shutter setting operation will be described.
When a set member (not shown) starts rotating, first,
The leading blade drive member is rotated clockwise against the urging force of the leading blade drive spring. As a result, the drive pin of the leading blade driving member rotates the arm 6 clockwise, so that the leading blades 8, 9, 10, and 11 are operated downward while reducing the amount of overlap therebetween. When the overlapping amount of the slit-forming blade 11 of the front blade and the slit-forming blade 19 of the rear blade reaches a predetermined amount, the set member pushes the rear blade driving member against the urging force of the rear blade driving spring. And start rotating clockwise. Therefore, since the drive pin of the rear blade drive member rotates the arm 14 clockwise, the rear blades 16, 17, 18, and 19 are operated downward while increasing the amount of overlap between them. Then, the blades 8, 9, 10, and 11 of the leading blade are in the deployed state and cover the opening 1a, and the blades 16, 17, 18, and 19 of the trailing blade are in the overlapping state and are located below the opening 1a. After being stored, the rotation of the set member is stopped, and the set state is set as shown in FIG.

[Second Embodiment] A second embodiment of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view shown in the same manner as FIG. 2, but as can be seen from this figure, in this embodiment, the shutter base plate 1 described in the first embodiment is provided with a wall 1r.
The other configuration is exactly the same as that of the first embodiment. The wall 1r also has an inclined surface 1s and extends to the outer edge of the shutter base plate 1. However, the fact that the wall 1r may be formed only at the edge of the opening 1a is the same as the case of the wall 5f described in the first embodiment.

As described above, according to the present embodiment, the amount of abrasion dust flying to the low-pass filter 22 from the blade chamber of the front blade as well as from the blade chamber of the rear blade can be suppressed. This is more effective than the embodiment. Further, in the case of the present embodiment, although the inclined surface 1s faces the low-pass filter 22, the light reflected on that surface does not proceed to the low-pass filter 22. In this embodiment, the shutter base plate 1 and the auxiliary base plate 5 are used.
In addition, although the wall 1r and the wall 5f are formed, in some cases, even if only the wall 1r is formed, a certain effect can be obtained. In addition, what has been described in the description of the first embodiment also applies to this embodiment.

Third Embodiment A third embodiment of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view shown in the same manner as FIG. 7, but as can be seen from this figure, in the present embodiment, a frame portion 1t is formed so as to surround the entire circumference of the opening 1a of the shutter base plate 1. ing. Also, shutter base plate 1
The auxiliary base plate 5 is coated or stuck with countless adhesives 23. Further, the adhesive 23 functions as an anti-reflection material. In FIG. 8, reference numerals are not given to other components, but they are exactly the same as those in FIG. 7, and all the components not shown in FIG. 8 are the same as those in the first embodiment. It has become.

As described above, according to this embodiment, the adhesive 23 provided on the surface inside the blade chamber so as not to affect the operation of the leading blade and the trailing blade removes the abrasion powder generated in each blade chamber. Because it will adhere, coupled with the existence of the walls 1r and 5f,
Abrasion powder that jumps out toward the openings 1a and 5a is greatly reduced. The adhesive 23 provided around the openings 1a and 5f is also included in the wear powder that has protruded toward the openings 1a and 5a.
Therefore, the amount of abrasion dust flying to the low-pass filter 22 is extremely limited so as not to affect the photographing. Furthermore, the adhesive 2 of the present embodiment
Numeral 3 is also an anti-reflection material, which reflects light from the shutter base plate 1 and the auxiliary base plate 5 during photographing, restricts light incident on the low-pass filter 22, and extremely reduces light leakage to the imaging surface when the camera is not used. It is also possible to limit. Others
What has been described in the description of the first embodiment and the second embodiment also applies to this embodiment.

Although the above embodiments have been described with reference to the case where the present invention is used for a digital camera, the present invention is also applicable to a camera using a film. Alternatively, one blade chamber may be formed by the shutter base plate and the auxiliary base plate.
Further, in each of the above embodiments, each shutter blade has four shutter blades.
It has a number of blades, but is not limited to the number of blades.
The number may be five or five. Further, in the above-described embodiment, the description has been made assuming that the shutter blade is operated by the drive spring. However, the present invention is also applied to the case where the shutter blade is operated by the electromagnetic driving means.

[0058]

As described above, according to the present invention, since the connecting shaft interposed between the arm of the shutter blade and the blade does not enter or leave the exposure opening during its operation, the exposure shaft formed on the base plate is not used. Abrasion powder is not generated by contacting the edge of the opening or the vicinity thereof. In addition, by forming a wall between the operating area of the arm and the opening for exposure with respect to the main plate, it is possible to make it difficult for the wear powder generated by the operation of the shutter blade to jump out of the blade chamber. is there. Therefore, it is possible to extremely reduce abrasion powder adhering to the imaging surface.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment viewed from a subject side, that is, a photographing lens side, and shows a state immediately before the start of an exposure operation.

FIG. 2 is a cross-sectional view showing a configuration inside a blade chamber for easy understanding, in which a configuration other than a main part is omitted.

FIG. 3 is a plan view showing individual blocks of the main constituent blocks shown in FIG. 1 except for an auxiliary base plate, wherein FIG. 3 (a) shows a shutter base plate and FIG. 3 (b) 3C shows the front blade, FIG. 3C shows the intermediate plate, and FIG. 3D shows the rear blade.

FIG. 4 is a plan view of the auxiliary base plate employed in the first embodiment, as viewed from the subject side.

FIG. 5 is a plan view of the first embodiment as viewed from the image sensor side, and shows a rear blade immediately after the end of an exposure operation.

FIG. 6 shows a state immediately after the exposure operation of the first embodiment is completed.
FIG. 4 is a perspective view viewed in the same manner as in FIG.

FIG. 7 is a sectional view of the second embodiment shown in the same manner as FIG. 2;

FIG. 8 is a sectional view of the third embodiment shown in the same manner as FIGS. 2 and 7;

FIG. 9 is a plan view for explaining a conventional example.

[Explanation of symbols]

1, A Shutter base plate 1a, 4a, 5a, Aa, Ba, Ca Opening 1b, 1c, 1d, 6a, 14a Slot 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1m Axis 1n, 1p, 1q , 4b, 4c, 4d, 5b, 5c, 5
d hole 1r, 5f wall 1s, 5g inclined surface 1t frame body 2, 3 buffer member 4, B intermediate plate 5, C auxiliary base plate 5e light shielding wall 5h end surface 5i concave portion 6, 7, 14, 15, D, E arm 8, 9, 10, 11, 16, 17, 18, 19, F,
G, H, I Blades 12, 13, J, K Connecting shaft 20 Screw 21 CCD 22 Low-pass filter 23 Adhesive

Claims (11)

[Claims] 1. A blade chamber is formed between two base plates having an opening for exposure at a substantially central portion, or an opening for exposure is provided at a substantially central portion. The intermediate plate
Two blade chambers are formed to partition between the ground plates, and shutter blades disposed in the blade chambers are pivotally connected at one end to one of the ground plates at a position lateral to each of the openings. A plurality of arms, and one or more blades pivotally supported by those arms by each connecting shaft,
A focal plane shutter for a camera, wherein an operation trajectory of each of the connecting shafts does not enter an opening of the main plate. 2. At least one of the two ground plates includes:
2. A wall is formed between the opening formed in the main plate and the operating area of the arm so as to protrude toward the blade chamber along the edge of the opening. 2. A focal plane shutter for a camera according to claim 1. 3. The focal plane shutter for a camera according to claim 2, wherein the wall is formed so as to extend to an outer edge of the main plate. 4. The apparatus according to claim 2, wherein the wall is formed on a base plate disposed on the imaging surface side, and the wall forms an inclined surface facing the subject. The focal plane shutter for a camera according to the above. 5. The method according to claim 5, wherein the size of the end face of the opening in a direction parallel to the optical axis is smaller than the thickness of the ground plate on which the slope is formed. The focal plane shutter for a camera according to claim 4, characterized in that: 6. The focal plane shutter for a camera according to claim 2, wherein the wall is formed by integral molding of a synthetic resin, or by protruding and crushing a metal plate. . 7. The intermediate plate according to claim 2, wherein the intermediate plate partitions between the two ground plates, and is attached so as not to move relative to the two ground plates. 7. The focal plane shutter for a camera according to any one of 6. 8. The shutter blade has a plurality of blades, and the wall formed on the blade chamber side of the shutter blade has a larger amount of protrusion in a direction in which the shutter blade is deployed. The focal plane shutter for a camera according to any one of claims 2 to 7, wherein the focal plane shutter is formed as described above. 9. The focal plane shutter for a camera according to claim 2, wherein an adhesive is applied or affixed to a surface of the wall on the operation area side of the arm. 10. The focal plane shutter for a camera according to claim 9, wherein the adhesive is also an anti-reflection material. 11. The imaging device according to claim 11, wherein the ground plane disposed on the imaging surface side has a recess for receiving a part of the low-pass filter or the imaging device so as to surround the opening on the imaging surface side surface. The focal plane shutter for a camera according to any one of claims 1 to 10, wherein: