JP3801685B2 - Camera shutter device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a camera shutter device of a type called a lens shutter that opens and closes a circular exposure opening by a plurality of shutter blades when photographing.
[0002]
[Prior art]
In this type of shutter, during the exposure operation, the shutter blade opens the exposure opening from the center of the optical axis and then closes toward the center of the optical axis. Therefore, it is ideal to keep the opening shape as close to a circle as possible. For this reason, in the past, a plurality of (five many) shutter blades are arranged at equal intervals around the exposure opening and are operated by a drive ring that reciprocally rotates around the optical axis. . However, the shutter having such a configuration has an extremely large frictional resistance on the sliding surface of the drive ring, and various measures are required to cope with the increase in the shutter speed. For this reason, there is a problem that the cost is high and it is difficult to meet the cost reduction that is required by the times.
[0003]
Since then, with the advancement of film technology and lens technology, the above-mentioned opening shape during operation has not been said so severely, and rather, cost reduction has been emphasized. For this reason, the type using a drive ring disappears except for a professional large shutter, and instead, a two-blade shutter, which was formerly called a vario type, has become mainstream. However, in a shutter of a normal grade or higher that requires a certain level of performance, the opening shape during the operation described above cannot be greatly collapsed, and it is necessary to keep the minimum shape close to a circle. is there. For this reason, the outer shape and dimensions of each blade have been determined so as to follow it. However, recently, not only cost reduction, but of course, the demand for downsizing and electrification has increased. In particular, the demand for downsizing has become extremely large.
[0004]
[Problems to be solved by the invention]
By the way, in the case of downsizing the lens shutter, the size of the accommodation space of the shutter blades when the exposure opening is fully opened, in other words, an annular plane centered on the optical axis necessary for the accommodation. The radial dimension of the part is one big guide. However, the shutter having the two-blade configuration as described above has already been miniaturized to a point where a minimum shape close to a circle cannot be maintained as a normal grade shutter when further miniaturized. Therefore, in order to eliminate this point and further reduce the size, it is absolutely necessary to use three or more shutter blades. However, in that case, the drive ring cannot be used for the reason described above. In addition, when using a motor as a drive source due to the demand for electrification, it is necessary to reduce the size of the motor itself for the purpose of downsizing the shutter. As a result, the driving force must be weakened. ing. Further, in order to reduce power consumption, it is required that the driving force be weak. Therefore, it is not appropriate to use the above-described drive ring having a large frictional resistance from such a point.
[0005]
On the other hand, instead of the drive ring as described above, an actuating member called a link member that requires a small frictional resistance is provided, and a shutter for opening and closing the shutter blades is proposed by the present applicant. Known in the Gazette. However, although the shutter having such a configuration is advantageous in that the frictional resistance is small, since the reciprocating operation of the operating member is performed in the direction crossing the optical axis, the above-described shutter is used to reduce the size of the shutter. When the radial dimension of the annular flat surface portion is reduced, the connecting portion between the actuating member and the moving point portion of any one of the blades enters the exposure opening in operation. Will occur.
[0006]
The present invention has been made to solve such problems, and an object thereof is to open and close three or more shutter blades by an operating member that reciprocates in a direction crossing the optical axis. It is an object of the present invention to provide a camera shutter device in which the operating member does not need to enter the exposure opening even if the shutter device is downsized.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, in the camera shutter device of the present invention, an exposure opening having a fulcrum and a moving point at predetermined distance intervals and having a circular shape about the optical axis. Three or more shutter blades that open and close the opening for exposure by reciprocatingly rotating in the same direction around the fulcrum, and an optical axis that is rotatably connected to the moving point of each shutter blade. An operation member that reciprocally rotates each shutter blade at each fulcrum by reciprocating in a direction across the shutter, and a drive unit that is connected to the operation member and causes the operation member to reciprocate. In the opening / closing operation, the distance between the optical axes of the fulcrum portions of the shutter blades having the moving point portion closest to the opening for exposure is set to be longer than the distance between the optical axes of the fulcrum portions of the other shutter blades.
[0008]
In the camera shutter device of the present invention, it is preferable that the distances between the optical axes of the fulcrum portions of the shutter blades are all different.
In the camera shutter device of the present invention, it is preferable that the connection between at least one of the shutter blades and the operating member is a fitting connection by a pin and a long hole.
Furthermore, in the camera shutter device of the present invention, preferably, the driving means is a motor, and the connection with the operating member is a fitting connection by a pin and a circular hole or a pin and a long hole.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the examples shown in FIGS. FIG. 1 is a plan view of the embodiment, showing a shutter closed state. FIG. 2 is a cross-sectional view of the drive motor unit shown in FIG. 1, and FIG. 3 is an explanatory view showing a permanent magnet mounting part used in the drive motor. FIG. 4 is an explanatory view of the actuating member shown in FIG. FIG. 5 is a cross-sectional view showing the connection configuration of the actuating member and the shutter blade, and FIG. 6 is a cross-sectional view showing the position detection mechanism of the shutter blade. FIG. 7 is a plan view showing a fully opened state of the shutter. 1, 4, and 7, the front side of the drawing is the film side, and the back side is the subject side. In other drawings, the upper side is the film surface side and the lower side is the subject side.
[0010]
First, the configuration of the present embodiment will be described. The shutter base plate 1 and the auxiliary base plate 2 are made of synthetic resin, and both have circular openings 1a and 2a around the optical axis. In this case, since the diameter of the opening 1a is slightly smaller than the diameter of the opening 2a, the opening 1a is an exposure opening. As shown in FIG. 2, the shutter base plate 1 and the auxiliary base plate 2 are attached to each other by hanging a flexible hook portion 1 b formed on the shutter base plate 1 on the edge of the auxiliary base plate 2. A space is formed in In the present embodiment, such hook portions 1b are provided at three locations, but in FIG. 1 and FIG. 7, one of them is omitted.
[0011]
A plurality of walls 2b are formed on the outer peripheral edge of the auxiliary base plate 2 in some places, and as shown in FIGS. 5 and 6, it serves to shield light from the outer peripheral direction. As can be seen from these drawings, the interval between the shutter base plate 1 and the auxiliary base plate 2 is determined by the upper end of the wall 2b being in contact with the shutter base plate 1, but depending on the location, as shown in FIG. Protrusions 1c and 2c are formed on the shutter base plate 1 and the auxiliary base plate 2, respectively, and the distance can be regulated by bringing them into contact with each other. In the space formed between the shutter base plate 1 and the auxiliary base plate 2, the operating member 3 and the three shutter blades 4, 5, 6 are arranged so as to overlap a part thereof. . In this case, the operating member 3 is closest to the auxiliary base plate 2 and is in the order of shutter blades 4, 5, 6 toward the shutter base plate 1.
[0012]
As in FIG. 1, the operating member 3 and the shutter blade 4 in the shutter closed state are shown in FIG. As can be seen from this figure, the actuating member 3 has an annular shape, three elongated holes 3a, 3b, 3c having the same shape in the longitudinal direction, two elongated holes 3d, 3e in the horizontally elongated shape, and two circular holes. 3f, 3g and three overhanging parts 3h, 3i, 3j are formed, and among these, the three overhanging parts 3h, 3i, 3j are formed on the auxiliary base plate 2 as shown in FIG. The three base portions 2d, 2e, and 2f formed are in sliding contact. As will be understood from the following description, the actuating member 3 may be formed in a C shape or an inverted C shape by cutting a part thereof instead of being annular.
[0013]
Of the three shutter blades, the shutter blades 5 and 6 have the same shape, and the overhang portions 5a and 6a are formed at the tips, respectively. In the present embodiment, the overhanging portion 6a has no meaning. The reason for forming the overhang portion 5a will be described later. The fulcrum portions of the shutter blades 4, 5, 6 are not provided with reference numerals but are formed with circular holes, and these circular holes rotate about shafts 1 d, 1 e, 1 f formed on the shutter base plate 1. It is possible to fit. And the front-end | tip of each axis | shaft 1d, 1e, 1f is loosely inserted in the long holes 3a, 3b, 3c of the above-mentioned action | operation member 3. As shown in FIG. Incidentally, as shown in Figure 1, as although the axes 1e and the shaft 1f is the distance are both L ₁ from the optical axis center, the shaft 1d is a distance from the optical axis center is longer than L _1, the L ₂ Is set.
[0014]
The moving point portions of the shutter blades 4, 5, and 6 are rotatably attached to the operating member 3 by connecting shafts 7, 8, and 9, respectively. Their connection configuration will be mainly described with reference to FIG. FIG. 5 shows a connection configuration of the operating member 3 and the shutter blade 5. The connecting shaft 8 is formed with shaft portions 8a and 8b having different diameters, and a circular hole 3f of the operating member 3 is rotatably fitted to the shaft portion 8a. Further, after a hole formed in the shutter blade 5 is fitted into the shaft portion 8b, both are integrated by caulking. Similarly, the shutter blades 4 and 6 are attached by connecting shafts 7 and 9 at the positions of the holes 3e and 3g of the operating member 3, respectively. Further, as shown in FIG. 5, the auxiliary base plate 2 has relief grooves 2g corresponding to the operating regions of the connecting shafts so that the connecting shafts 7, 8, and 9 can operate without interference. Is formed. However, in FIGS. 1 and 7, the relief groove for the connecting shaft 9 is not shown for easy understanding of the drawings.
[0015]
Next, the configuration of the drive motor unit of the present embodiment will be described mainly with reference to FIGS. A yoke member 10 is attached to the surface side of the shutter base plate 1 with two screws 11. The rotor 12 of this motor is a coil bobbin and is rotatably supported by the shutter base plate 1 and the yoke member 10 as can be seen from FIG. A coil 13 is wound around the rotor 12 in a direction orthogonal to the rotation direction so as to avoid the rotation axis, and a drive pin 12 a formed integrally with the rotor 12 is provided on the shutter base plate 1. The hole 1g formed in an arc shape is passed through and fitted into the elongated hole 3d of the actuating member 3. And the cylindrical permanent magnet 14 used as the stator of the motor is placed on two chair-like pedestals 1h and 1i (see FIG. 3) provided on the shutter base plate 1, and is attached by an appropriate means such as an adhesive. It is fixed. In FIGS. 1 and 7, the drive pin 12a is shown in the shutter closed state and the fully open position. However, the rotor 12 is intentionally both in order not to obscure the drawings. It is shown in an intermediate position between the closed state and the fully opened state.
[0016]
In this embodiment, a detection device for the opening operation position of the shutter blade is provided. The configuration of the apparatus will be described mainly with reference to FIGS. A photo reflector 15 is attached to the auxiliary base plate 2 as a detection element. The photo reflector 15 has a light emitting portion 15a and a light receiving portion 15b, and light emitted from the light emitting portion 15a enters the working space of the shutter blade 5 from the slit-shaped hole 2h formed in the auxiliary ground plate 2, The light is reflected by the reflection sheet 16 attached to the shutter base plate 1 and enters the light receiving portion 15b. And the light radiate | emitted from the light emission part 15a to the reflective sheet 16 can be interrupted | blocked by the overhang | projection part 5a of the shutter blade 5 mentioned above.
[0017]
Next, the operation of this embodiment will be described. When the shutter is released in the shutter closed state of FIG. 1, first, the power switch is closed and the photo reflector 15 is energized. As a result, the light emitted from the light emitting unit 15a is reflected by the reflection sheet 16 and reaches the light receiving unit 15b, so that the photo reflector 15 emits an H level signal to an exposure time control circuit (not shown). Immediately thereafter, when the coil 13 wound around the rotor 12 is energized in one direction, the rotor 12 rotates counterclockwise. Accordingly, since the drive pin 12a moves upward in the arc-shaped hole 1g, the operating member 3 also moves upward due to the fitting relationship with the elongated hole 3d. The upward movement is the same as the distance between the fulcrum portions (the positions of the shafts 1d, 1e, and 1f) of the shutter blades 4, 5, and 6 and the moving point portions (the positions of the connecting shafts 7, 8, and 9). In addition, since the circular holes 3f and 3g of the operating member 3 are fitted (linked) with the connecting shafts 8 and 9, the circular arc is drawn.
[0018]
Thus, when the operation member 3 starts to operate, the shutter blades 4, 5, and 6 also start to rotate counterclockwise about the shafts 1d, 1e, and 1f, respectively. When the projecting portion 5a of the shutter blade 5 blocks the optical path of the photo reflector 15, counting by the exposure time control circuit is started by an L level signal that is an output signal thereof. FIG. 7 shows a state in which the shutter blades 4, 5, and 6 open the exposure opening 1 a about the optical axis and stop at the fully open position.
[0019]
In FIG. 7, the connecting portion between the actuating member 3 and the shutter blades 5 and 6 (that is, the vicinity of the connecting shafts 8 and 9 which are moving point portions of the shutter blades 5 and 6) is completely formed from the exposure opening 1a. However, the connecting portion between the actuating member 3 and the shutter blade 4 is in the proximity of the exposure opening 1a. If the distance between the optical axes of the axis 1d is L ₁ (see FIG. 1) as in the axes 1e and 1f, this connecting part completely penetrates into the exposure opening 1a. It will be. However, in this embodiment, as shown in FIG. 1, since the distance between the optical axes of the axes 1d is longer than L ₁ and L _2, it is not necessary to enter the exposure opening 1a.
[0020]
In the fully opened state of FIG. 7, when the exposure time control circuit finishes a predetermined count, the coil 13 is energized in the direction opposite to the above in accordance with the output signal. Therefore, the rotor 12 rotates in the clockwise direction, and the actuating member 3 is caused to return by the drive pin 12a. Accordingly, the shutter blades 4, 5, and 6 are rotated clockwise on the shafts 1d, 1e, and 1f, respectively, close the exposure opening 1a, and stop in the state shown in FIG. Then, the coil 13 and the photo reflector 15 are de-energized, and one shooting is completed.
[0021]
In the above embodiment, the hole 3e is a long hole among the holes 3e, 3f, 3g formed in the actuating member 3, but originally, the hole 3e may be a circular hole. preferable. However, in the embodiment, an example is shown in which the hole 3e is a long hole within a range where there is no problem in function in order to cope with manufacturing errors. Thus, in the present invention, various embodiments can be considered in addition to the examples. For example, in addition to the hole 3e, another hole (hole 3f or 3g) may be a long hole, and the three holes 3e, 3f, 3g are all long holes by making the long hole 3d a circular hole. It is also possible to do. Further, when the actuating member 3 is configured to linearly move by an appropriate guide means having a small frictional resistance, all the holes 3e, 3f, 3g are long holes without making the long holes 3d circular. It is also possible.
[0022]
In the above embodiment, three shutter blades are used from the viewpoint of cost reduction. However, the present invention is not limited to this and may be more than that. In the above embodiment, only the distance L ₂ between the optical axes of the axis 1d is different from the distance L ₁ between the optical axes of the other axes 1e, 1f, but all the distances between the optical axes are different. You can do that. Furthermore, in the above embodiment, the motor and the actuating member as the driving source are connected to each other by fitting the pin and the long hole (slot). Thus, it does not matter even if it is meshingly connected by a gear. Furthermore, the drive source is not limited to the motor, and a spring-driven opening / closing lever as well known may be used.
[0023]
【The invention's effect】
As described above, according to the present invention, even if the operating member that reciprocates in the direction crossing the optical axis is configured to open and close three or more shutter blades, the operating member is connected to the shutter blades. Since it is possible to prevent the vicinity of the connection from entering the opening for exposure, the configuration is extremely effective as a small shutter having a small frictional resistance.
[Brief description of the drawings]
FIG. 1 is a plan view of an embodiment of the present invention, showing a shutter closed state.
FIG. 2 is a cross-sectional view of a drive unit in the embodiment.
FIG. 3 is an explanatory view showing a permanent magnet attachment portion in the embodiment.
FIG. 4 is an explanatory view of an operation member in the embodiment.
FIG. 5 is a cross-sectional view illustrating a connection configuration between an operation member and a shutter blade in the embodiment.
FIG. 6 is a sectional view showing a shutter blade position detection mechanism in the embodiment.
FIG. 7 is a plan view of the embodiment of the present invention, showing a fully opened state of the shutter.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shutter base plate 1a, 2a Opening part 1d, 1e, 1f Shaft 1h, 1i Base 2 Auxiliary base plate 2d, 2e, 2f Base part 2g Escape groove 3 Actuating member 3a, 3b, 3c, 3d, 3e Long hole 3f, 3g Circular hole 3h, 3i, 3j, 5a Overhang portions 4, 5, 6 Shutter blades 7, 8, 9 Connecting shaft 10 Yoke member 12 Rotor 12a Drive pin 14 Permanent magnet

Claims (4)

Each of the fulcrum portions has a fulcrum portion and a moving point portion at a predetermined distance interval, and the fulcrum portion is reciprocally rotated in the same direction around the exposure opening having a circular shape around the optical axis. Three or more shutter blades that open and close the opening, and a moving point portion of each shutter blade are rotatably connected to each other to reciprocate in the direction crossing the optical axis so that each shutter blade is moved at each fulcrum portion. A shutter blade having a moving point portion that is closest to the exposure opening in the opening / closing operation of the shutter blade; The camera shutter device is characterized in that the distance between the optical axes of the fulcrum portions is set to be longer than the distance between the optical axes of the fulcrum portions of the other shutter blades. The camera shutter device according to claim 1, wherein the distances between the optical axes of the fulcrum portions of the shutter blades are all set differently. 3. The camera shutter device according to claim 1, wherein the connection between at least one of the shutter blades and the operation member is a fitting connection using a pin and a long hole. The camera shutter device according to claim 1, wherein the driving unit is a motor, and the connection with the operation member is a fitting connection by a pin and a circular hole or a pin and a long hole.

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