JP2599504Y2 - Optical element shielding device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element shielding device, more specifically, a front surface of an optical element can be covered by displacing a plurality of barrier elements from a predetermined open position to a closed position. The present invention relates to an optical element shielding device.

[0002]

2. Description of the Related Art Conventionally, a barrier opening / closing mechanism, which is an optical element shielding device for protecting a lens mounted on a camera, slides a barrier, which is a barrier element, in a predetermined direction or with a predetermined axis center. The barrier is opened and closed by turning. The barrier opening / closing mechanism is housed in the front exterior body of the lens barrel. When the barrier is open, the barrier is retracted to the outer diameter side of the lens opening. Therefore, in the case of the above-described slide drive barrier mechanism, the outer shape of the lens barrel becomes large, or the barrier storage portion protrudes in an unnatural form. FIG.
FIG. 1 is an external view of such a conventional video camera, and shows an example in which a barrier storage unit 102 is provided on the left side of a lens 101. On the other hand, when the barrier is opened and closed by rotation, the barrier is housed along the outer circumference of the lens. Therefore, as shown in the external view of FIG. 18, the lens barrel outer shape 104 of the lens 103 is formed in a cylindrical shape. Becomes possible. When the outer shape of the lens barrel is circular, it has a good effect on the design of the entire camera. However, it is necessary to make the outer shape as small as possible, and for that purpose, it is necessary to increase the number of barriers of the rotary barrier opening / closing mechanism.

[0003] Therefore, it is necessary to apply a conventional aperture mechanism using a large number of blades to the above-mentioned miniaturized rotary barrier opening / closing mechanism. FIG. 8 is a diagram showing an operation state of one blade 32 of a plurality of cantilevered blades of the conventional aperture device, and FIG. 8A shows an open state,
(B) shows a closed state. FIG. 9 is a front view of a wheel 33 for rotating the blade 32. Feather 32
Is rotatably supported by a support pin 32a supported by an exterior body 31 having an opening 31a. The driving pin 32b of the blade is fitted in the driving cam groove 33a of the wheel 33, and the rotation of the wheel 33 opens and closes the blade 32. However, if this structure is applied to the barrier mechanism as it is, the barrier itself is exposed to the outside, and it is conceivable that an external force acts on the tip of the blade serving as the barrier. And if the blade | wing 32 is cantilever as mentioned above, it will be easy to bend and it is not preferable.

In order to solve the above-mentioned drawback, it is necessary to apply a blade driving mechanism in which the blades are supported at both ends to a barrier mechanism, as shown in the schematic diagram of the diaphragm viewed from the lens side of the diaphragm device in FIG. Occurs. In FIG. 10, the shape of each barrier is indicated by a solid line without using a hidden line (broken line) even in a superimposed portion. Similar displays are also made for FIGS. 11, 5, and 6 described later. By the way, the blade 50 of this diaphragm device
Each of the reference numerals 56 to 56 has a seven-piece configuration, in which a support pin 5a serving as a fulcrum is provided at one end, and a drive pin 5b is provided at the other end straddling the opening 41a of the exterior body 41. And the arrow wheel 42
The rotation of the drive pin 5 fitted into the drive groove 42a
b is driven to open and close the aperture. However, in the case of this diaphragm device, in the minimum diaphragm state, as shown in FIG. 10, an opening CO remains at the center. Therefore, when this mechanism is applied to a barrier opening / closing mechanism, it is necessary to further rotate the arrow wheel 42 so as to eliminate the gap at the center. However, if a large number of blades serving as a plurality of barriers overlap in the central portion, the central overlapping portion of the blades is deformed so as to swell in the direction of the optical axis O, resulting in an appearance defect. Furthermore,
In such a state where the blades overlap with the central portion, the driving load increases, which is not preferable in terms of the balance of the load of the driving motor.
In addition, if the center gap is to be strictly eliminated, the central edges of a large number of blades must be brought into contact with the center of the optical axis O.
The dimensional accuracy required for each part also becomes severe.

Therefore, as shown in a schematic diagram showing the movement of one blade in FIG. 11, only a few blades constituting the barrier are rotated up to the optical axis O, and contact each other on the optical axis. Contact Then, it is conceivable that the other blades are stopped by pivoting to the positions where they are further retracted. That is, of the plurality of blades of FIG. 10 constituting the barrier mechanism, only the blades 51, 54, and 56 are rotated until the center edge of the blade reaches the center of the optical axis O (hereinafter, referred to as an overstroke position). The other blades 50, 52, 53, 55 are shown in FIG.
Rotate to a position just before the overstroke position shown in FIG. By driving in this manner, a completely closed state can be obtained, and further, the swelling and the increase of the driving load as described above do not occur. As shown in FIG. 11, the driving pins 5b of the blades 50 to 56 are 5b in the open state.
A, the blades 50, 52, 53, 5 in the closed state
5, the drive pin 5b is at the position of the drive pin 5bB, and
The drive pins 5b of the blades 51, 54, 56 at the overstroke position are rotated to the positions of the drive pins 5bC, respectively. The rotation trajectory of the drive pin 5b at this time is
It passes on an arc CL centered on a. FIG. 12 shows the state of the blades 50 to 56 in the open state.
14 shows the turning positions of the blades 50, 52, 53, 55 in the closed state, and FIG. 14 shows the turning positions of the blades 51, 54, 56 in the closed state with one blade.

[0006]

As described above, only the predetermined blade is rotated more than the other blades, and
Japanese Patent Laid-Open Publication No.
No. 38 discloses a blade drive mechanism of an aperture control device. This mechanism includes a lens opening 61 as shown in FIG.
and a plurality of blades 64 rotatably mounted on an exterior body 61 having a drive pin 64b.
2 is driven. The thrust direction of the wheel 62 is regulated by a retaining ring 63. The driving of the wheel 62 is performed by a motor 65 via a gear 66. Then, in order to change the rotation angle of each blade 64, the drive groove 62a of the wheel 62 that fits into the drive pin 64b of the blade to be rotated extra is provided at the tip thereof as shown in FIG. The portion is lengthened by 62a '. on the other hand,
The drive groove 62b of the wheel 62 that fits into the drive pin of the blade that does not need to be turned excessively is bent from a predetermined portion of the tip thereof as shown in FIG. The groove 62b 'is formed in the radial direction. By configuring the driving groove of the arrow wheel 62 in this way, a difference can be given to the rotation angle of the blade. However, it is not very appropriate to apply such a mechanism to the blade drive mechanism of FIG. This is because, in the mechanism of FIG. 11, since the position of the drive pin 5b is far from the fulcrum, the rotation angle is reduced accordingly.
Therefore, since the moving range of the drive pin 5b needs to be used to the maximum, the distance L1 and the distance L3 are set to be substantially equal, and the distance L2 to 5bB which gives the rotational position of the drive pin 5b is equal to the distance L3. Less than. Therefore, as shown in FIG. 16, even when the tip of the drive groove of the wheel wheel is bent, the location of the open drive pin position 5bA (see FIGS. 11 and 12) is also affected. It is bad.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a structure capable of reducing the outer shape around a lens barrel of a camera into a small cylindrical shape and sufficiently withstanding an external force. Moreover, an object of the present invention is to provide an optical element shielding device having a simple configuration.

[0008]

An optical element shielding device according to the present invention is built in a camera exterior body and is disposed on a front portion of a photographing lens supported by a lens barrel, and a plurality of barrier elements are provided. An optical element shielding device adapted to cover the front surface of the photographing lens by being displaced from a predetermined open position to a closed position, wherein the first drive groove for displacing the plurality of barrier elements and the first drive groove are provided.
A second or a larger groove width that is larger than the first drive groove by a predetermined dimension;
A displacement transfer element of annular and a subsequent drive groove, the upper
A first drive groove of the displacement transmission element is provided so as to be engaged with the first drive groove;
It has a drive member, which is configured to be rotationally displaced in accordance with the rotation of the displacement transmission element, the predetermined portion of each of the optical element at the center of the front surface, or abut on each other at a position in the vicinity thereof, or,
A first barrier element group that sets the first position superimposed and finally advanced to a position covering the front surface of the optical element as the respective closed position, and the second to the displacement transmission elements,
It has a drive member provided to engage with the subsequent drive groove.
And, adapted to rotationally displaced with the rotation of the displacement-transmitting element, a second and relatively recessed from the first position of said first barrier element group, to said each subsequent position , The second through the subsequent barrier element groups at the closed position, and the first barrier element group and the second,
To drive the barrier element groups subsequent to each other in a predetermined range, the second, subsequent barrier element groups are rotated by the sliding resistance of the barrier.
While maintaining the biased state in the opposite direction to the
After the first barrier element group by the predetermined dimension
And a driving mechanism for driving back.

[0009]

When the barrier of the optical element shielding device is closed,
The first group of barrier elements is driven via the displacement transmitting element to a first position where the vicinity of the optical axis is completely closed, and the second group of barrier elements reduces a larger backlash of the displacement transmitting element. As a result of driving at the holding portion, it is driven to the second position retracted from the first position, and the shielded state is maintained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiment. An embodiment of the present invention will be described with reference to FIGS. 1 is an exploded perspective view of the barrier device, FIG. 2 is a longitudinal sectional view,
FIG. 3 is a sectional view taken along line AA of FIG. 2 with the barrier element removed.

This barrier device is a device that enables the front surface of a photographic lens, which is an optical element, to be covered by a barrier element. As shown in FIG. 2, an exterior body 1 supported by a camera body (not shown) is provided. And is disposed on the front surface of the taking lens 2 supported by the lens barrel 3. The exterior body 1 has a lens opening 1b in a size that does not kick the outermost ray H of the photographing lens 2, and is also provided with a screw 1a for mounting a conversion lens and a filter.
Then, as shown in FIG. 1, each of the seven barrier elements 70 to 76 is rotatably inserted by inserting each support pin 7 a of the barrier element into a barrier support hole 1 d of the exterior body 1 which is an annular structural member. It is held at a predetermined interval.
Each of the barrier elements 70 to 76 has a drive pin 7b. Further, the regulation of the direction of the optical axis O around the openings of the elements 70 to 76 is regulated by the barrier body 3 a held by the exterior body 1 and the lens barrel 3. Then, the first barrier element group 71, 74, 76, which is rotated to the first position, the overstroke position, and the second position, which is retracted from the overstroke position, by the drive position in the closed state. Are divided into the second barrier element groups 70, 72, 73, and 75 which are rotated to the set positions. In addition,
The barrier element is hereinafter referred to as a barrier.

The drive pin 7b of each barrier is an annular drive member with the barrier disposed on the upper surface, and
Are respectively fitted or inserted into the drive grooves 5a and 5b. The drive groove 5a has the first barrier group 7
1, 74 and 76 drive pins 7b are fitted, and the groove width is set to a size approximately equal to that of the drive pins 7b. Therefore, it is driven without backlash. The drive pins 7b of the second barrier groups 70, 72, 73, 75 are fitted into the drive grooves 5b.
The width of the groove is larger than the drive pin 7b by a predetermined dimension, and when driven, the groove is driven with a predetermined backlash characteristic. In addition, those groove width shapes are shown in FIG. The regulation of the arrow wheel 5 in the optical axis O direction is as follows.
6 is a position protruding toward the inner diameter side from an imaginary peripheral surface surrounding and surrounding the convex portions 70d and 73d of FIG. 6 in the open state of the barrier group on the inner peripheral surface of the barrier group. It is regulated by the wheel bearings 1c provided at a plurality of locations at the concave portions 70c and 73f of the portion (see FIGS. 3 and 6). Further, the restriction on the photographing lens side is restricted by a stop ring 6 that is elastically deformed and fitted into a ring groove 1 e provided in the exterior body 1. The height of the arrow wheel receiving portion 1c in the optical axis direction is, as shown in the sectional view of FIG.
Are housed, and have dimensions that allow opening and closing operations. Also,
The rotation direction is regulated by a stopper 5 projecting outward from the wheel 5.
c contacts the exterior body 1 and is regulated.

When the arrow wheel 5 rotates counterclockwise as viewed from the lens side until the stopper 5c comes into contact with the exterior body 1, the barriers are opened (see FIG. 6). The actuator 16c of the open state detection switch 16 to which the switch 1 is attached is pressed by the stopper 5c, and the conductive contact pieces 16a and 16b are brought into contact (see FIG. 3). Then, an open state detection signal is output. Also,
The wheel 5 is clockwise as viewed from the lens side.
When the armature rotates until it comes into contact with the exterior body 1, each of the barriers is closed (see FIG. 5). At this time, the actuator 15c of the closed state detection switch 15 to which the exterior body 1 is attached is moved by the stopper 5c. Pressed conductive contacts 15a and 15
b is in contact. Then, a closed state detection signal is output. The driving of the wheel 5 is performed by a driving motor 1 serving as a driving source.
2, through a sector gear-8 meshing with the output gear-13. The sector gear 8 is fixed to the wheel 5 via a mount 9. The drive motor 12 is
It is fixed to the exterior body 1 via a mounting base 11. As shown in the front view of FIG. 4, the retaining ring 6 has protrusions 6a, 6b, 6c that engage with the ring groove 1e of the exterior body 1 arranged on the outer side. An escape portion 6d for the sector gear 8 is provided at the end on the inner diameter side of the ring.

The opening and closing operations of the barrier device of the present embodiment configured as described above will be described with reference to FIGS. FIG. 5 is a schematic diagram showing the operation positions of the barrier and the arrow wheel in the barrier closed state when the barrier device is viewed from the photographing lens side. All are indicated by solid lines. FIG. 6 is a schematic diagram showing the operation positions of the barrier and the arrow wheel in the barrier open state, also when the barrier device is viewed from the photographing lens side.
However, only the barriers 70 and 73 of all the barriers are shown by solid lines so that the open state can be clearly understood. It is also assumed that other barriers are similarly retracted from the opening 1b of the exterior body 1 to a position outside.

First, when the wheel 5 is rotated clockwise, each barrier is rotated in the closing direction. The first barrier group 71 in which the drive pin 7b is fitted in the drive groove 5a,
74 and 76 are driven without play, and rotate to an overstroke position (first position) where the inner edge of the barrier is located on the optical axis O position. On the other hand, the second barrier groups 70 and 7 in which the drive pins 7b are inserted into the drive grooves 5b with large backlash.
2, 73, 75 are driven backward by the amount of backlash while maintaining a state of being urged counterclockwise by the sliding resistance of the barrier. When the wheel 5 reaches the barrier closing position, the second barrier group 70, 72, 73, 75 is set.
Are the overstroke positions (first positions), respectively.
It turns to the second position slightly earlier.

Therefore, in this closed state, the opening 1b of the exterior body 1 is completely shielded. Moreover,
The first barrier groups 71, 74, and 76 are the only barriers superimposed or in contact with the vicinity of the optical axis O, and the second barrier groups 70, 72, 73, and 75 remain at positions slightly retreated. Therefore, the swelling in the direction of the optical axis at the central portion unlike the above-described conventional example is less likely to occur. Also,
Regarding the driving load, the operation of forcibly superimposing all the barrier groups on the central portion is avoided, so that the fluctuation of the load is reduced.
Further, it is also advantageous for suppressing the remaining portion of the central gap.

Next, in the barrier opening operation, the wheel 5 is rotated counterclockwise, and each barrier is rotated counterclockwise to drive in the opening direction. However, the second barrier groups 70 and 7
2, 73, 75 are urged clockwise by sliding resistance, and are driven backward by the amount of backlash only at the start of movement. When the wheel 5 reaches the barrier open position, the first and second barrier groups 70 to 76 are simultaneously rotated to the barrier open position. FIG. 6 shows the open state of only the barriers 70 and 73, but the other barriers are also rotated to the same open position.

As shown in FIG. 6, it is possible that the wheel carrier receiving portion 1c of the exterior body 1 is provided inside a virtual peripheral surface formed by the maximum protruding portions 70d, 70e and 73d of the barrier. As described above, the maximum protruding portions 70d, 7
Reference numerals 0e and 73d denote projecting portions required to prevent the generation of gaps in each barrier closed state as shown in FIG. And, the part of the projection that does not overlap with the projection part, that is, the part of the concave part 70c or 73f,
By forming c, the external dimensions of the exterior body 1 having the built-in barrier mechanism can be reduced to the extent that the opening drive of each barrier is not hindered.

As a modified example of the shape of the driving groove 5b of the wheel 5 as shown in FIG.
By setting the distance L1 to the open drive pin position 5bA to be smaller than the distance L2 to the closed drive pin position 5bB, as shown in the plan view of the arrow wheel in FIG. It is also possible to make the driving groove 55b for driving a wide groove in the vicinity of the outer shape so that the second barrier can be rotated only to the second position. Here, the drive groove 55a for driving the first barrier group is the same as that in the above embodiment. Further, in the embodiment,
Although the two barrier groups are examples of a plurality of numbers, each of the barrier groups may be a single barrier. Further, although the embodiment has the first and second barrier groups, the present invention is not limited to this, and a third group or a fourth group is provided, and the third group or the fourth group stays at the position where the barriers are sequentially retracted in the closed state. It may be configured as follows.

[0020]

As described above, in the optical element shielding device of the present invention, a plurality of barriers are divided into a plurality of groups, and when the barriers are closed, the rotation drive position is changed for each group. Therefore, the device of the present invention does not cause the problem that the central portion is raised even in the barrier closed state,
Variations in the driving load of the barrier drive can be suppressed, and moreover, there are many remarkable effects, such as the outer shape of the exterior body in which the barrier is built can be made smaller.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a barrier mechanism which is an optical element shielding device showing a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the barrier device shown in FIG. 1;

FIG. 3 is a cross-sectional view taken along the line AA of FIG. 1 and showing a state where each barrier is removed.

FIG. 4 is a front view of a stop ring used in the barrier device of FIG. 1;

FIG. 5 is a schematic view showing a barrier and a driving position of a wheel in a barrier closed state of the barrier device of FIG. 1;

FIG. 6 is a schematic view showing a barrier in a barrier open state of the barrier device of FIG. 1 and a driving position of a wheel.

FIG. 7 is a view showing a modified example of the arrow wheel of the barrier device of FIG. 1;

8A and 8B are diagrams showing the operating state of a blade in a conventional cantilever blade type aperture device having a structure that can be used also as a barrier device, wherein FIG. 8A shows an open state and FIG. Show.

FIG. 9 is a front view of the arrow wheel used in the aperture device of FIG. 8;

FIG. 10 is a schematic diagram showing a closed state of a conventional double-ended supporting blade type aperture device having a structure that can be used also as a barrier device.

FIG. 11 is a diagram showing each operation state of one blade in a conventional double-ended supporting blade type aperture device having a structure that can be used also as a barrier device, in which an overstroke blade is provided.

FIG. 12 is a diagram showing an open state of one blade in the aperture device of FIG. 11;

FIG. 13 is a diagram showing a closed state of one blade in the aperture device of FIG. 11;

FIG. 14 is a diagram showing a closed state of one blade at an overstroke position in the aperture device of FIG. 11;

FIG. 15 is an exploded perspective view of a main part of a conventional diaphragm device having a structure that can be used as a barrier device.

16 (a) and 16 (b) are diagrams showing the drive grooves of the impeller of the aperture device of FIG. 15 described above, wherein (A) shows the shape of the drive grooves of the impeller for normal blades, and (B) shows the impeller for the overstroke blades. Are shown below.

FIG. 17 is an external view of a conventional video camera.

FIG. 18 is an external view of another conventional video camera.

[Explanation of symbols]

5, 55 ····································································································································································· 13 ... Output gear (drive mechanism) 71, 74, 76 First barrier group (first barrier group)
70, 72, 73, 75 ... second barrier group (second barrier element group)

Claims (1)

(57) [Scope of request for utility model registration] 1. A plurality of barrier elements are disposed in a front part of a photographing lens which is built in a camera exterior body and supported by a lens barrel, and is displaced from a predetermined open position to a closed position. An optical element shielding device adapted to cover a front surface of the photographing lens, wherein a first element for displacing the plurality of barrier elements is provided .
The groove width is larger than the first driving groove by a predetermined dimension.
An annular displacement transmitting element having a second or subsequent drive groove, and an annular displacement transmitting element provided to engage with the first drive groove of the displacement transmitting element.
Having a driving member, which is configured to be rotationally displaced in accordance with the rotation of the displacement transmitting element, and a predetermined portion of each of the optical elements abuts each other at the center of the front surface of the optical element, or at a position in the vicinity thereof, A first barrier element group that sets the first position, which is superimposed and finally advances to a position covering the front surface of the optical element, as the respective closed position, and the second to subsequent displacement transmission elements, Engage in drive groove
A driving member provided so as to be engaged with each other, and is configured to be rotationally displaced in accordance with the rotation of the displacement transmitting element.
A second or subsequent barrier element group that sets the respective second or subsequent positions relatively retracted from the first position of the barrier element group to the respective closed positions; and the first or second barrier element group; When the barrier element group and the second to subsequent barrier element groups are driven so as to be linked in a predetermined range, the second, second and subsequent barrier element groups are rotated and displaced by the sliding resistance of the barrier. Opposite direction
While maintaining the biased state, the first barrier
An optical element shielding device, comprising: a driving mechanism for driving the element group backward by the predetermined dimension .