JPS59165036A - Totally-enclosed iris stopping device - Google Patents

Abstract

PURPOSE:To prevent the interference with another stopping blade by uniforming the shape and size of all stopping blades and forming a slight bending part on the tip of only one stopping blade to form a totally-enclosed stopping blade. CONSTITUTION:When a stopping ring is rotated in the counterclockwise direction, the guide pins 7 of the stopping blades 1A-1G are slid in respective guide grooves 6A-6G and rotated in the counterclockwise direction around a supporting shaft 5 to reduce the aperture of the stop. Since only the point part of the totally-enclosing stopping blade 1G located on the uppermost part abutted to the inner peripheral edge of a stopping blade 1C, the blade 1G runs on the inner peripheral edge of the stopping blade 1C along the inclined surface in accordance with the additional rotation of the stopping ring and halts after reaching a position covering the minimum stopping aperture formed by other stopping blades 1A-1F although other stopping blades 1A-1F halts on the minimum stopping position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an iris diaphragm device that controls YC, particularly a fully closed iris diaphragm device that can completely close the aperture. Fade-in tfnU and fade-out s shadows are performed to gradually brighten the image or, conversely, to gradually darken both bright sides until it becomes completely dark. In order to perform this fade-in/fade-out function w78, the aperture device of the tfJa lens must have a so-called aperture cut function that can completely close its aperture. Also, especially with TV cameras, the shooting is easy! In order to protect the tube and alignment element from glare and to maintain their performance over a long period of time, it is essential to have an aperture cut function that fully closes the aperture when not in use.

Conventionally, there have been several methods for fully closing the diaphragm aperture, including a method in which a diaphragm device is constructed with two intersecting aperture blades, a method in which the minimum aperture aperture of an iris diaphragm device is wrapped in another shielding plate, and the method is completely closed. A method of providing a partition plate Z is known in order to avoid the inconvenience of the aperture blades interfering and interlocking with each other when they are displaced to the narrowing side, making the narrowing operation impossible.

In this conventionally known diaphragm device, the method using two diaphragm blades has a drawback in the shape of the diaphragm aperture, and the method in which a shielding plate is installed separately causes oblique light rays to leak through the gap between the diaphragm blades and the shielding plate. In addition, the method of isolating each aperture blade with a partition plate limits the number of aperture blades, and the outer diameter of the aperture ring that holds the aperture blades becomes larger than the open aperture of the aperture. None of these conventional methods are satisfactory.

Therefore, as a method to eliminate the drawbacks of the conventional fully closed iris diaphragm and device as described above, the C-shaped aperture blades are extended to more than a semicircle to increase the amount of overlap with other blades. Utility Model Publication No. 48-43376 discloses a structure in which the aperture blades are overlapped along the circumference so that they do not interfere with each other even when the aperture is fully closed.

However, because the shaft pin that supports the aperture blades and the movable pin that rotates the aperture blades are both implanted in protrusions that project radially from the arcuate outer periphery of the aperture, the shape of the aperture blades is complicated and the aperture blades are Not only does this increase the friction surface of C1, which may lead to a lack of smooth diaphragm adjustment operation, but it also increases the outer diameter of the diaphragm device, making it impossible to downsize the lens device.

``The present invention solves the drawbacks of the conventional device as described above, and makes the aperture blades 31 extremely simple and almost identical in shape 7.
To provide a small and inexpensive totally closed type iris diaphragm device in which the blades do not interfere even when the diaphragm is completely closed.

In order to achieve the above object, in the present invention, when the diaphragm diameter is reduced, the free end side of the aperture blades that engage with the plurality of guide grooves provided in the aperture operating ring or the aperture aperture is In an iris diaphragm device configured to gather toward the center, a bent portion having a slope sloped toward the diaphragm opening is formed at the free end of one of the plurality of iris blades, so that the entire iris diaphragm device is configured to gather toward the center. The tail part of the guide groove that is formed as a closing aperture blade and engages with the fully open aperture blade is inclined more toward the center of the aperture opening than the tail part of the guide groove that engages with other aperture blades. After forming the minimum aperture diameter,
It is characterized in that the fully closing aperture blade is displaced so as to cover the minimum aperture opening formed by the other aperture blades.

Hereinafter, the present invention will be described in detail based on embodiments illustrated in the accompanying drawings.

1 is a partial sectional view showing a seventh embodiment of the present invention, FIG. 2 is a left side view of FIG. 1, and FIG. 3 is a sectional view taken along line AA of FIG. 1. The seven aperture blades I8 to 1G forming the aperture aperture are
The aperture ring 3 is held between the fixed ring 2 and the aperture ring 3, and the aperture ring 3 is driven by an actuating shaft 4 that penetrates the circumference of the fixed ring 2 and is implanted in the aperture ring 3. It is configured to be able to rotate within the fixed ring 2 by a predetermined angle. In the fixed group 2, as shown in FIG. 2, seven fulcrum holes 2b are formed on a concentric circle centered on the opening 2C of the fixed ring 2, with equal distances apart, and the crest blades shown in FIG. IA to IF and fully closing aperture blades IG shown in FIG. 5 are rotatably held by a fulcrum hole 2h via a fulcrum pin 5 implanted at one end. In addition, the aperture operating ring 3 includes
As shown in No. 31vl, spiral guide grooves 6A to 6G are provided around the opening 3a, and six guide grooves 68 to 6 are provided.
F are all formed to the same shape and size, and the untailed part 6a close to the periphery of the opening 3a is concentric with a predetermined central angle θ! 7
1! , (same radius r). In addition, the remaining one fully closing guide groove 6G has a groove portion other than the predetermined center angle θ formed in the same shape as the other guide grooves 6A to 6F, and the center of the tail portion 6b near the opening 3a. Even in the range of the angle -θ, the groove is formed in a direction that is inclined toward the center of the opening 3a. These guide grooves 6A to 6G have guide pins 7 (fourth
5) is slidably inserted into the guide groove 6.
A to 6F correspond to the aperture blades IA-IF, and the fully open guide groove 60 corresponds to the fully open aperture blade IG.

Note that the size and outline of the bristle blades IA to IF in FIG. 4 and the fully closing aperture blade 1G in FIG. Although it is flat, the free end of the fully closed aperture blade IG has a slightly inclined surface and is bent as shown in Figure 5A.
The difference is that a bent portion 1b is provided.

6 to 8 are sectional views taken along line B-B in the embodiment shown in FIG. 1, in which FIG. 6 shows the aperture in a fully open state, FIG. 7 shows an intermediate aperture state, and FIG. 8 shows the aperture in a fully closed state L'= shows.

In the fully open state of the aperture, as shown in Fig. 6, the aperture blades IA to 1 (1) are provided on the circumference so that their parts overlap one after another, and the fully closed aperture blades 1 (1 get tm < other apertures Feather I
A to IF are configured such that parts of them overlap each other vertically. However, only the fully closing aperture blade IG is shown at the top in FIG. 6 and is provided so as not to be covered by the other aperture blades. In addition, as is clear from FIG. 6, the length from the fulcrum pin 5 of the aperture blades IA to IF to the free end 1a is such that a portion of the length extends from at least two aperture blades (
For example, form it so that it is placed under IG and IA) for IF.

Since the embodiment of the present invention is configured as described above, the sixth embodiment
As shown in the figure, when the fully opened aperture ring 3 is rotated counterclockwise (in the direction of arrow C), the guide pins 7 of the aperture blades IA to 10 slide within the guide grooves 68 to 6G, respectively. Then, it pivots counterclockwise around the fulcrum shaft 5. Therefore, each of the aperture blades IA to NG rotates counterclockwise about the fulcrum @5, thereby reducing the aperture aperture to an intermediate aperture state as shown in FIG. In this case, the fully closed aperture blade IG
The free ends of each of the other aperture blades lA to IF except
None of them enters the lower part of another adjacent aperture blade and comes into contact with the inner circumferential edge of that aperture blade. but,
The bent end portion 1b of the fully closing aperture blade IG at the top abuts the inner circumferential edge IC of the other crest blade IC. Here, if the tip of the fully closed aperture blade lG is connected to another diaphragm blade Ji
If it is not bent like the tips 1a of tA to IF, it may collide with the inner circumferential edge 1C of the aperture blade IC, making the shape of the aperture irregular and deteriorating the aperture precision.
There is a risk of damaging the aperture blades.

However, since the tip of the fully closing aperture blade 1G in this embodiment is provided with a bent portion 1b as shown in FIGS. 5 and 5A, the rotation of the aperture operating ring 3 in the counterclockwise direction is Accordingly, fully closed aperture blade IG and other aperture blade IC
When both rotate about their respective fulcrum pins 5 in the opposite direction d1, the bent portion 1b of the fully closing aperture blade IG
rides on the inner circumference Plc of the aperture blade IC along the inclined surface.

increase. Therefore, the aperture blades IG and 1c do not undergo any abnormal deformation, and the diaphragm blades IG and 1c are adjusted to a predetermined size.
often reduced.

Further, when the diaphragm operation ring 3 rotates counterclockwise and the guide pin 7 slides in each of the guide grooves 68 to 6G, the crest wings 4it&to IG rotate around the fulcrum shaft 5, respectively. Rotate clockwise and the aperture diameter becomes the predetermined minimum aperture.Here, if you continue to rotate the aperture movement control 3 counterclockwise, all the aperture blades except for the fully closed aperture blades and the limit 10y will open. The guide pins of IA and IF' are in guide grooves 6A to 6, respectively.
It slides within the tail portion 6a of the concentric groove F. Therefore, the six aperture blades IA-IF do not rotate counterclockwise and remain at their minimum aperture position. Therefore, it is possible to prevent the aperture blades from interfering with each other, which would occur when the aperture diameter is extremely reduced, causing the aperture blades to mesh with each other, making it impossible to perform a narrowing operation, or to prevent abnormal deformation of the aperture blades due to the meshing. On the other hand, since the guide pin 7 of the fully-closed aperture blade i (1) slides within the inclined tail portion 6b of the fully-closed guide groove 6G, the fully-closed aperture blade 1G acts as the center of the fulcrum pin 5. It then rotates counterclockwise until it reaches a position covering the minimum diaphragm opening formed by the other diaphragm blades IA-IF and stops, as shown in FIG.

As described above, the diaphragm is completely closed, but the formation of the diaphragm aperture by the diaphragm blades, especially the diaphragm blade IA in FIG.
~As is clear from the arrangement of IG, each aperture blade IA~IG
The tip portions 1a and lb are portions that do not participate in any way in forming the diaphragm aperture, that is, in forming the shape and size of the diaphragm aperture. Therefore, even if a bent portion iby as shown in FIGS. 5 and 5A is formed in this portion, the aperture diameter will not be affected in any way. In addition, in order to accommodate the bent portion 1b of the fully opening aperture blade IG when the aperture is fully opened, it is desirable to provide a notch groove 2a on the inner surface of the fixed ring 2, as shown in FIG. Furthermore, as is clear from Figure 6,
The length from the fulcrum pin 5 of the aperture blades IA to IF to the free end 1a is so formed that it can be placed under the -. Therefore, from the maximum aperture to the minimum aperture, not only do the aperture blades not interfere with each other during the aperture operation, but the gap between the stacked surfaces of the aperture blades is 1jP.
There is no light leaking from there.

In the above embodiment, the number of aperture blades is described as seven, but the number may be four or more, and of course may be seven or more.

Furthermore, in this embodiment, the aperture blades other than the fully closed aperture blades are configured not to be displaced after the minimum aperture is formed, but the aperture aperture may change to some extent unless the aperture blades are deformed. There is no problem.

As described above, according to the present invention, all shapes of the aperture blades,
The size of the diaphragm blade is the same as 7, and the tip of only one aperture blade is formed with a slight bend to form a fully open aperture blade. Interference with the blades can be completely avoided. moreover,
When the aperture 103 ring is operated after the minimum aperture diameter is formed, the fully open aperture blade rides on top of the other aperture blades and moves to cover the minimum aperture opening formed by the other aperture blades. The aperture operation is smooth, the aperture precision is high, the 14 cylinders can be made small, and the aperture opening can be completely closed reliably.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an example of the present invention, FIG. 2 is a left side view of the embodiment shown in FIG. 1, and FIG.
-A sectional view, FIGS. 4 and 5 are respectively enlarged plan views of the aperture blades used in the embodiment of FIG. 1, FIG. 5A is a left side view of the aperture blades of FIG. 5, and FIGS. Fig. 8 is a sectional view taken along line B-B in Fig. 1, showing changes in the aperture diameter. Fig. 6 shows the aperture in the fully open state, Fig. 7 shows the aperture in the middle open state, and Fig. 8 shows the aperture in the fully closed state. FIG. IA~IF...6 aperture blades IG...Full opening aperture blade 1b...Bending portion 2...Fixed ring 3...Friction operation ring 2c, 3 a.=psE7i40 6 8~6G...Guide groove 6a, fib...Guide groove Mibi Applicant: Nippon Kogaku Kogyo Co., Ltd. Representative: Takashi Watanabe Male spear 6 figure 27 Inko 〆ku

Claims (1)

[Claims] (1) In an iris diaphragm device having a plurality of aperture blades that rotate around their respective fixed fulcrums so that their respective tips gather toward the center of the aperture aperture when the aperture aperture is reduced, the plurality of apertures All the blades are formed to have the same outline shape, and a bent part is formed at the tip of one of the aperture blades to be inclined in the opposite direction to the side in contact with the other aperture blades to form a fully closed aperture. Shape J4' with the remaining aperture blades and the fully closed aperture blades.
v? A completely closed type iris diaphragm device configured to cover the minimum diaphragm aperture. (2. In the iris diaphragm device according to claim 1, the plurality of diaphragm blades are connected to the one fully closing diaphragm blade (IG), and when the diaphragm is fully opened, a part thereof is on the lower side of each other. A fully closed iris diaphragm device comprising at least three aperture blades (lA-tF) arranged in an overlapping annular manner.