JPH09311363A - Shutter blade device for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a split blade system shutter blade device for a camera adaptable to both of a lens shutter and a diaphragm device and suitable for miniaturization. SOLUTION: Shutter blades 5, 6, 7 and 8 are separately and rotatably attached to the shafts 1c, 1d, 1e and 1f of a shutter base plate 1, an operation pin 4a for an opening/closing operation member 4 is fitted into each oblong hole 5a and 8a, etc., of the blades. And when an aperture 1a is in a closed state, the operation pin 4a is separated from the optical axis, then, in order to make the shutter blades 5, 6, 7 and 8 in the completely open state, the operation pin 4a should be moved in a nearly optical axis direction. When the blades are in the completely open state, the blades 5 and 6 overlap each other to the maximum 5, and also, the blades 7 and 8 overlap each other to the maximum, and also, the tips of the blades 6 and 7 overlap each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-shielding blade device for a camera which can be applied to both a lens shutter device and a diaphragm device.

[0002]

2. Description of the Related Art A light-shielding blade used in a lens shutter device or a diaphragm device controls opening and closing of a circular exposure opening centered on the optical axis. Is ideally as close to a circle as possible at any aperture position. For that reason, there was once 3
One or more light shielding blades are arranged and they are operated by a ring member that reciprocally rotates about the optical axis. However, the light-shielding device having such a configuration has a very large frictional resistance force on the sliding surface of the ring member and requires a large driving torque. Therefore, it is difficult to increase the speed in the case of the shutter device. However, in the case of the diaphragm device, there is a problem that it is difficult to support the automatic diaphragm device.

Since then, with the progress of film technology and lens technology, the shape of the aperture formed by the light-shielding blade has become less strict, and the cost reduction has become more important. Therefore, although the type using the ring member is still adopted for high-end cameras, it has become more and more popular to use two-blade shading blade devices for cameras of intermediate grade or lower. Moreover, some shutter blades also have the function of a diaphragm device by shifting from the middle of the opening operation to the closing operation of the two shutter blades. However, even with such a shading blade device, in a camera of a normal grade or higher that requires a certain level of performance, the above-described aperture shape cannot be greatly destroyed, and the minimum shape close to a circle is The outer shape and size of each blade were determined along the same.

Recently, however, the demand for miniaturization has become extremely large, not to mention cost reduction. By the way, in the case of downsizing the lens shutter and the diaphragm device, the size of the housing space of the light-shielding blade when the exposure opening is fully opened, in other words, the optical axis necessary for the housing is the center. The radial dimension of the ring-shaped flat surface portion is one large guide. Therefore, not only is it necessary to reduce the outer diameter of the entire apparatus, but it is also necessary to determine how large the diameter of the exposure opening can be for the same outer diameter.

However, the light-shielding blade device having the two-blade structure as described above has already been downsized to the point where it cannot be further downsized. Therefore,
In order to eliminate this point and further reduce the size, the conventional two blades are divided into two pieces, respectively, and when the blades are fully opened, the overlapping of the divided blades becomes large, thereby reducing the above-mentioned accommodation space. Such an arrangement is known from Japanese Patent Laid-Open No. 2-226129 and Japanese Utility Model Laid-Open No. 3-22227. In addition, Japanese Utility Model Laid-Open Publication No. 64-4212 discloses a blade which is devised so that the above-mentioned opening shape is close to a circle by dividing the blade in such a manner.

However, the light-shielding blade device having such a structure has recently been used as a relatively high-speed shutter device, and is automatically operated in a predetermined aperture position and immediately stopped in association with the release of the camera. Since it is used as a diaphragm device, it must always be able to obtain stable operation. Further, in order to stably obtain such an instantaneous operation, it is necessary for each light shielding blade to have a fulcrum portion pivotally supported by a fitting connection between the circular hole and the shaft. The present invention relates to a light-shielding blade device provided with such divided blades, and all of these blades have a fulcrum portion having the above-mentioned configuration.

[0007]

By the way, it is not easy to further reduce the size of the shading blade device of this type. In the above-mentioned Japanese Utility Model Laid-Open No. 64-4421, the fulcrum position of each blade is common, and the position is on an extension of the line connecting the optical axis and the operating pin (driving pin). Since it is located far away from the optical axis from the actuating pin, other spaces are small, but this fulcrum position is large in the radial direction, and the space effect is not so good. Rather, on the contrary, there is a problem in that the layout in the camera is restricted.

Further, there is one in which the fulcrum positions of the respective light-shielding blades are at different positions so that the above-mentioned overhang can be made smaller than that disclosed in Japanese Utility Model Laid-Open No. 64-4212. It is described in JP-A-64-526. However, also in this case, the required space is not averaged around the optical axis, and more or less places restrictions on the design in the camera. As described above, it is preferable that the accommodation space cannot be obtained on average around the optical axis, especially for a camera provided with a zoom lens, as a device that is housed in a cylinder protruding over the entire surface of the camera body. Absent.

On the other hand, the above-mentioned Japanese Patent Laid-Open No. 2-226 has a structure in which the accommodation space is obtained relatively averagely around the optical axis and the arrangement of the camera is hardly restricted.
129 and Japanese Utility Model Laid-Open No. 3-22227. However, in these configurations, when downsized, the tips of the blades that are relatively operated at full opening are
It is difficult to keep them on top of each other. fact,
Therefore, a partition called a separation plate (or an intermediate plate) is provided to prevent the tips of the blades that are relatively operating from meshing with each other (the end faces of the plate thickness collide) during the closing operation. Moreover, when such a partition wall is provided, a gap is formed between the blades by the thickness of the partition wall, and when used as a shutter device, light leakage may occur in the closed state. If the overlapping of the blades in the closed state is to be increased in order to prevent the light leakage, it is against the miniaturization.

The present invention has been made in order to solve such a problem, and an object of the present invention is to reduce a small deviation around a circular exposure opening centered on the optical axis. It is an object of the present invention to provide a divided blade type light shielding blade device for a camera, which can be arranged in a space and is suitable for downsizing.

[0011]

In order to achieve the above object, in the light-shielding blade device for a camera of the present invention, the actuating pin is formed substantially at the lateral position of the circular exposure opening centered on the optical axis. An opening / closing operation means for reciprocating in the optical axis direction,
Each set is composed of two light-shielding blades having a long hole that fits into the operating pin, and these two light-shielding blades are substantially symmetrical with respect to a straight line passing through the operating pin and the optical axis. And a plurality of sets of light-shielding blades that are rotatable with respect to the fulcrum, the plurality of sets of light-shielding blades are arranged such that the distance from the straight line to the fulcrum position is different for each group,
Further, the overall shape of each of the light shielding blades is formed so as to be convex toward the respective fulcrum position sides with respect to the straight line.

Further, in the light-shielding blade device for a camera of the present invention, it is preferable that the tips of the light-shielding blades of the group having the smallest distance from the straight line to the fulcrum position are mutually positioned at the fully open position of the exposure opening. So that they overlap. Further, in the light-shielding blade device for a camera of the present invention, preferably, during the opening / closing operation of the light-shielding blade, in a working region having a small opening shape, a group of light-shielding members having a smallest distance from the straight line to the fulcrum position is shielded. The blade regulates the opening shape, and in the working area larger than that,
The shape of the opening is regulated in cooperation with the shading blades of the other set. Further, in the light-shielding blade device for a camera of the present invention, preferably, the distances from the fulcrum positions of the light-shielding blades to the optical axis are all substantially the same.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the embodiments shown in FIGS. Although the structure of this embodiment can be used as both a shutter device and a diaphragm device, it will be described here as a shutter device. FIG. 1 is a plan view showing a closed state of an exposure opening, FIG. 2 is a plan view showing an intermediate opening state before full opening, and FIG. 3 is a plan view showing a fully opened state. Further, in order to facilitate understanding of the effect of the present invention, a comparative example with respect to the embodiment will be described with reference to FIG. 4 showing a closed state and FIG. 5 showing a fully opened state. Since it is considered that there is no possibility of causing confusion, the reference numerals used in the examples are used in the comparative examples.

First, the configuration of the embodiment will be described with reference to FIG. The shutter base plate 1 is made of synthetic resin and has a circular opening 1a centered on the optical axis. The front side is the film side and the back side is the subject side in the drawing. Although only a part is shown in FIG. 1, an auxiliary base plate 2 is attached to the film side of the shutter base plate 1 at a predetermined interval, and a blade chamber is formed between the two base plates. A substantially circular wall 1b is formed on the outer peripheral portion of the shutter base plate 1 to block light entering the blade chamber from the outer peripheral direction. Actually, the auxiliary base plate 2 also has a circular opening centered on the optical axis,
In the case of the present embodiment, since the diameter of the opening 1a is slightly smaller, the illustrated opening 1a is the exposure opening.

The shutter base plate 1 is provided with 4 toward the blade chamber.
Book shafts 1c, 1d, 1e and 1f are provided upright and slit holes 1g are formed. Light emitting unit 3 of photo reflector 3 attached to the subject side of shutter base plate 1
a and the light receiving portion 3b are arranged to face the inside of the blade through the slit hole 1g. Although not shown because it is well known,
A reflection sheet is attached to the blade chamber side of the auxiliary base plate 2, and the light emitted from the light emitting section 3a is reflected by the reflection sheet and enters the light receiving section 3b. Also,
A shaft 1h is erected on the subject side of the shutter base plate 1, and an opening / closing operation member 4 is rotatably attached to the shaft 1h. The opening / closing operation member 4 is provided with an operation pin 4a, which penetrates a long hole (not shown) formed in the shutter base plate 1 and projects into the blade chamber.

In the blade chamber, shutter blades 5, 6, 7,
8 are stacked and housed in order from the shutter base plate 1 side. These shutter blades 5, 6, 7 and 8 are formed with a circular hole and an elongated hole, respectively, and each of the circular holes has a shaft 1c, 1a.
d, 1e, 1f are fitted to each other, and the long hole is provided with the above-mentioned operating pin 4a.
Is fitted. Further, the overall shape of each blade is formed so as to be convex toward the circular hole rather than toward the elongated hole. Since each shutter blade has such an arrangement, it can be reciprocally rotated by the operating pin 4a with the shafts 1c, 1d, 1e, 1f as fulcrums.
In addition, in FIG. 1, among the long holes of each blade, the blades 5, 8
Only the long holes 5a and 8a are shown and the others are omitted.

Of these blades, the shutter blades 5 and 8 pivotally supported by the shafts 1c and 1f have the same shape but different orientations, and the shafts 1c and 8 serving as the fulcrum thereof.
Since the position 1f is substantially symmetrical with respect to the straight line passing through the optical axis and the drive pin 4a, the reciprocating operation of the operation pin 4a causes substantially symmetrical operation. Further, the shutter blades 6 and 7 pivotally supported by the shafts 1d and 1e have the same shape except that the shutter blade 7 is formed with the projecting portion 7a, and the shaft 1d serving as the fulcrum thereof. , 1e are substantially symmetrical with respect to a straight line passing through the optical axis and the drive pin 4a, they are operated substantially symmetrically by the operation pin 4a. However, in the shafts 1c and 1f and the shafts 1d and 1e, the latter has a smaller distance to the above straight line, so that the operating angle becomes larger than the former.

Next, the operation of this embodiment will be described. In the shutter closed state of FIG. 1, when the shutter is released, first, the power switch is closed and the photo reflector 3 is turned on. As a result, the light emitted from the light emitting section 3a is reflected by the reflection sheet (not shown) and reaches the light receiving section 3b, so that the photo reflector 3 issues an H level signal to the exposure time control circuit (not shown). Immediately after that, the driving means (not shown) rotates the opening / closing operation member 4 counterclockwise on the shaft 1h. Therefore, the operation pin 4a moves in the optical axis direction while drawing an arc, and causes the shutter blades 5, 6, 7, 8 to open and start the operation. At this time, since the fulcrum position of each blade is different as described above,
The vanes 5,6 will operate in a clockwise direction with increasing mutual overlap, while the vanes 7,8 will similarly operate in a counterclockwise direction with increasing mutual overlap.

In this way, each shutter blade 5, 6,
When the projection portions 7a of the shutter blade 7 block the optical path of the photoreflector 3 when the shutters 7 and 8 start to operate, the exposure time control circuit starts counting by the L level signal which is the output signal thereof. After that, a pinhole is formed at the optical axis position by the shutter blades 6 and 7, and thereafter, the opening 1a is opened about the optical axis. At this time, the opening shape is formed by the shutter blades 6 and 7 up to the middle and maintains a relatively safe shape, but thereafter, it becomes difficult to maintain a shape close to a circle.
However, in the present embodiment, the shape of the edge of the shutter blades 5 and 8 on the optical axis side is different from the shape of the edge of the shutter blades 6 and 7 on the optical axis side. Due to the difference in the operating angle, the edges of the shutter blades 5 and 8 on the optical axis side join the formation of the opening shape from the middle. Such a situation is shown in FIG.

Thereafter, the shutter blades 5, 6, 7 and 8 are
When the state is further rotated from the state shown in FIG. 2, the opening 1a is fully opened, and the state shown in FIG. 3 is obtained. Thus, this embodiment is
In the closed state, the operating pin 4a is located away from the optical axis, and when the opening operation is performed, the operating pin 4a moves in the optical axis direction. This is an essential constitution for downsizing of the present embodiment, which will be described later in detail.
Further, as can be seen from FIG. 3, the shutter blades 6 and 7 that are adjacent to each other in the optical axis direction and operate in the opposite directions are
The tips overlap. Therefore, in the closing operation, each blade is prevented from meshing (colliding) with the blade operating from the opposite direction toward the optical axis.

As described above, in the fully open state shown in FIG. 3, when the exposure time control circuit finishes the predetermined count determined by the subject light or the like, the opening / closing operation member 4 is rotated clockwise by the driving means (not shown). To be made.
Therefore, the shutter blades 5 and 8 are rotated counterclockwise by the operation pin 4a, and the shutter blades 6 and 7 are rotated clockwise to close the opening 1a and stop in the state of FIG. Then, the power supply to the photo reflector 3 is cut off, and one photographing is completed.

In the above description of the embodiment, the shutter blades 5, 6, 7 and 8 are closed after the fully opened state shown in FIG. Can be a shutter device that can be closed from the state before the fully opened state, for example, the state shown in FIG. 2, according to the subject light, and can also be used as a diaphragm device. . In the above embodiment, two sets of blades having different distances from the straight line passing through the optical axis and the actuating pin 4a to the fulcrum position are used.
It is also possible to provide three or more sets of one blade, which is particularly effective in the case of a diaphragm device.

Further, in the above embodiment, the shafts 1c, 1d, 1e and 1f, which are the fulcrums of the respective blades, are provided at substantially the same distances from the optical axis, which is also a small size of the entire apparatus. Contribute to However, the present invention is not limited to such a configuration. Further, in the above embodiment, the shafts 1c, 1d, 1e, 1f are provided upright on the shutter base plate 1, but if necessary, some or all of them may be provided on the auxiliary base plate 2. Alternatively, the shaft and the hole forming member may be reversed (for example, the shaft 1c).
Is erected on the shutter blade 5 and a hole for fitting the shutter blade is formed in the shutter base plate 1). Further, the reciprocating operation of the opening / closing operation member 4 may be motor drive or spring drive.

Next, the comparative example shown in FIGS. 4 and 5 will be described. 4 shows the closed state of the opening 1a, and FIG.
Indicates a fully open state. In these figures, the outer diameter of the shutter base plate 1 and the diameter of the opening 1a are set to be the same as those in the above-described embodiments. Further, the positions of the shafts 1d and 1e are also the same, and the structure and arrangement of the opening / closing operation member (4) are also the same although they are not shown. Therefore, the operating pin 4a is adapted to reciprocate along the same locus as in the embodiment. However, in this comparative example, the operating direction of the operating pin 4a at the time of opening / closing operation is opposite to that of the above-described example, and the blades 5,
The shapes and operating directions of 6, 7 and 8 are different.

In this comparative example, the reciprocating operation of the operation pin 4a during the opening / closing operation is performed in the same manner as that described in each of the above-mentioned publications. That is, the opening 1a
In the closed state, the operating pin 4a is located near the optical axis, operates in the outer diameter direction of the shutter base plate 1 in the opening operation, and returns in the optical axis direction in the closing operation. Along with that, the operating directions of the blades 5, 6, 7, and 8 are opposite to those in the above-described embodiment, and the shape of each blade is inevitably changed. That is, the entire shape of each blade is formed so as to be convex not on the fulcrum side but on the operating pin 4a side that is the moving point, and during the opening operation, the blades 5 and 6 rotate counterclockwise and the blade 7 moves. , 8 rotate clockwise. Further, in order to open and close each blade in a predetermined manner, the shafts 1c and 1f in the embodiment are not provided, and the fulcrum pin 5b of the blade 5 is provided in the circular hole formed at the same position as the shaft 1c. Is rotatably fitted, and the fulcrum pin 8b of the blade 8 is rotatably fitted in a circular hole formed in the auxiliary base plate (2) so as to correspond to the position of the shaft 1f.

According to the comparative example configured as described above, FIG.
As shown in FIG. 4, in the fully open state, the space is within the same space as in the above embodiment, but in the closed state, the tips of the blades 6 and 7 do not protrude from the outer diameter of the shutter base plate 1 as shown in FIG. Get lost. That is, the overlapping conditions of the blades 6 and 7 in the closed state are set to be substantially the same as those in the embodiment, and the opening shape during the operation of the blades is set to be substantially the same as that in the embodiment, and the fully opened state is set. If it is attempted to make the tips of the blades 6 and 7 overlap with each other, the distance between the operation pin and the optical axis at the time of full opening becomes longer than in the case of the embodiment, so the length of the tips of the blades 6 and 7 should be made longer. Inevitably, in the closed state, a space in the outer diameter direction is required accordingly. Thus, by comparing with the comparative example, it can be understood how the present invention is suitable for miniaturization.

[0027]

As described above, according to the present invention, since the light-shielding blades can be housed in the annular space centered on the optical axis substantially uniformly, the size of the split-blade type light-shielding blade device can be further reduced. It is extremely effective for

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention showing a closed state of an exposure opening.

FIG. 2 is a plan view showing an intermediate opening state before full opening in the embodiment.

FIG. 3 is a plan view showing a fully open state in the embodiment.

FIG. 4 is a plan view of a comparative example with respect to the example, showing a closed state of the exposure opening.

FIG. 5 is a plan view showing a fully open state of a comparative example.

[Explanation of symbols]

 1 Shutter base plate 1a Opening 1b Wall 1c, 1d, 1e, 1f, 1h Axis 1g Slit hole 2 Auxiliary base plate 3 Photo reflector 3a Light emitting part 3b Light receiving part 4 Opening / closing actuating member 4a Operating pin 5, 6, 7, 8 Shutter blade 5a , 8a Long hole 5b, 8b Support point pin 7a Overhanging part

Claims (4)

[Claims] 1. An opening / closing operation means for reciprocating an operating pin in a direction substantially in the optical axis at a side position of a circular exposure opening centered on the optical axis, and an elongated hole in which each set is fitted to the operating pin. A plurality of pairs of light-shielding blades having a plurality of light-shielding blades, and the two light-shielding blades are rotatable with a substantially symmetrical position as a fulcrum with a straight line passing through the operating pin and the optical axis interposed therebetween. And a plurality of sets of light-shielding blades are arranged such that the distance from the straight line to the fulcrum position is different for each set, and the overall shape of each light-shielding blade is larger than that of the straight line. A light-shielding blade device for a camera, which is formed to have a convex shape on the side of each fulcrum position. 2. The tip of the pair of light-shielding blades having the smallest distance from the straight line to the fulcrum position overlaps each other at the fully open position of the exposure opening. The shading blade device for a camera according to 1. 3. During the opening / closing operation of the light-shielding blades, in the operating region where the opening shape is small, the opening shape is regulated by the pair of light-shielding blades whose distance from the straight line to the fulcrum position is the smallest, and The shading device for a camera according to claim 1 or 2, wherein the opening shape is regulated in cooperation with another set of shading blades in a large operating area. 4. The light-shielding blade device for a camera according to claim 1, wherein the distance from the fulcrum position of each light-shielding blade to the optical axis is substantially the same.