JP2848413B2 - Light intensity diaphragm device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a light amount aperture device such as a video camera or a still camera, and more particularly, to a light amount diaphragm in the same direction or a reverse direction between a diaphragm base plate and a cover. The present invention relates to a light-amount iris device having a plurality of diaphragm fins for adjusting an aperture or a light-receiving aperture on an optical axis by moving in a direction.

[Prior Art] As a light amount aperture device, there are generally known a swing type which draws a curved locus on aperture blades and a slide type which moves linearly.

As shown in FIG. 6, the swing type includes a pair of diaphragm blades 4 and 5 which are operated by an operating lever 2.
And the working bins 2c and 2d engaged with the openings 4f and 5f, respectively. Accordingly, when the operating lever 2 is driven in a predetermined direction, the aperture blades 4 and 5 become the guide members 1b and 1b provided on the main plate 1 and the long holes 4a and 4b formed in the blades.
Guided by 4b, 5a, 5b, they move relatively in the same or opposite directions, and the aperture 10 can be changed as appropriate.

The aperture base plate 1 is provided with an opening on the optical axis, and a similar opening is formed in a cover that sandwiches or covers a plurality of aperture blades in cooperation with the base plate.

On the other hand, as shown in FIGS. 7 to 10, the slide type aperture device has a pair of two long holes 4e, 4d,
5c, 5d, and on the other side elongated holes 4e, 5e are respectively formed,
Four guide pins erected on the main plate 1 are provided in these long holes.
1c is engaged. 9 and 10, the diaphragm blades 4 and 5 are slidably provided between the diaphragm base plate 1 and the cover 6.

The base plate 1 has a substantially rectangular shape, and an opening 1f is formed on the optical axis at the center. A driving device 7 is provided on the back side. Although not described in detail, the driving device is generally constituted by components 7a to 7j.

A drive lever 2 is engaged with a shaft 7 'of the drive device 7, and drive pins 2c and 2d provided at both ends of the lever.
Are engaged with the long holes 4f, 5f of the blades 4, 5, respectively. An end of the blade 4 is cut out in a substantially arc shape to form a light receiving opening 4i, and a substantially central portion of the blade 5 is cut out in a circular shape to form a light receiving opening 5i. The openings 4i and 5i cooperate to adjust the amount of received light. Reference numeral 3 indicates a spring, and when the driving device 7 is stopped, the light receiving opening is closed by the restoring force of the spring. The cover 6 also has an opening 6a on the optical axis.

As described above, since the blades are guided by the plurality of guide pins spaced in the longitudinal direction or the sliding direction,
The aperture blade moves linearly. On the other hand, when guided by one guide pin as shown in FIG. 6,
Swing a little.

[Problems to be Solved by the Invention] By the way, in the conventional aperture devices described above, since the aperture blades are each formed with an elongated hole, the length of the base plate is increased by the amount of the elongated holes 4a to 5e. There is a disadvantage that the widths W ₂ and W ₃ are large. In addition, the longitudinal directions L ₂ and L ₃ also increase due to the formation of the long holes. Especially in swing type shown in Figure 6, the movement locus of the blades 4 and 5, between the lateral line of the ribs 1e and wings of the base plate 1 must take apart as shown in FIG. 7, the width W ₂ Becomes bigger by that.
The elongated hole 4c is a slide-type shown in FIG. 8, 4d and 5c, because 5d are provided in series, the length L ₃ of the base plate 1 becomes more prolonged, and failure to reduce the size of the aperture device or camera Has become.

Therefore, an object of the present invention is to provide a light-amount aperture device that can form an aperture device with a ground plate that is short in both the width direction and the length direction.

[Means for Solving the Problems] In order to achieve the above object, according to the first aspect of the present invention, a diaphragm base plate having an opening formed on an optical axis and moving with respect to the base plate A plurality of diaphragm blades, which are freely supported and are adapted to move in different directions to adjust the amount of light passing through the opening, a diaphragm device comprising: A guide portion partially formed inwardly from the portion is provided, and when the plurality of diaphragm blades move in different directions from each other, both sides of the diaphragm blade contact the guide member, so that the diaphragm The blade is guided in the moving direction.

Similarly, in the present invention according to claim 2, the guide member according to claim 1 is formed with a step to guide the plurality of aperture blades so as not to contact each other in the optical axis direction. It is characterized by the following.

[Operation] In the present invention, since a plurality of diaphragm blades which are relatively movable in the same or opposite directions are provided between the main plate and the cover as described above, these blades are appropriately moved. The amount of light can be adjusted. During this movement, both sides of the diaphragm blade are guided by the guide members.

As described above, the diaphragm blade does not have a long hole for guiding as in the related art, and is guided by the side, so that the width of the main plate can be reduced. Further, since there is no need to provide a long hole, the length direction can be shortened.

Further, according to another invention in which a step is formed in the guide member, the step acts as a spacer, and the surface contact of the aperture blade can be avoided. Therefore, the moving resistance of the blade is small, and the light receiving area can be smoothly adjusted.

[Embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the aperture device according to the present embodiment includes an aperture base plate 1, a cover 6, and aperture blades 4, 5 provided therebetween.

The base plate 1 has a substantially rectangular shape, and a driving device 7 is provided on an outer portion, and a driving shaft 7 ′ of this device protrudes inward. The drive lever 2 is engaged with the drive 7 '. Therefore, when the driving device 7 starts, the driving lever 2 rotates, and as a result, the driving pins 2a, 2b provided at both ends.
The aperture blades 4 and 5 are relatively driven or moved via.

An opening 1f is formed substantially on the optical axis at the center of the aperture base plate 1. A guide member 1a is provided on the side of the opening, that is, on the inner side of the rib 1e of the base plate in the illustrated embodiment.
Are provided. These guide members guide vanes, which will be described later, and have a substantially arc-shaped cross section as viewed in plan as shown in FIG. 2 in order to reduce contact resistance. For smoother guidance, the number of guide members may be increased and the guide members may be densely provided, or may be made of Teflon or the like having a small frictional resistance.

The cover 6 cooperates with the squeezed base plate 1 to house the blades 4 and 5 therein. An opening 6a that matches the opening 1f of the base plate is formed substantially at the center.

The aperture blades 4 and 5 make a pair, and have long holes 4h and 4h formed at both ends thereof.
Drive pins 2a and 2b are engaged with each other. The other end is cut out in an arc shape to form light receiving openings 4i and 5i. These aperture blades 4, 5 are arranged at predetermined intervals as shown in FIG. 3, and both sides thereof are guided in contact with the guide member 1a.

 Next, the operation of the above embodiment will be described.

Since the spring 3 is provided between the shaft of the drive lever 2 and the ground plate, for example, when the drive device 7 is stopped,
The opening is closed. Then, when the drive device is started, the drive lever 2 rotates by a predetermined amount about the drive shaft 7 '. As a result, the diaphragm blades 4, 5 engaged with the drive pins 2a, 2b slide, and the areas of the light receiving openings 4i, 5i change,
The amount of light is adjusted appropriately. Aperture blades 4 and 5 when sliding
Are guided by the guide member 1a.

As described above, according to the present embodiment, the guide member is
Is provided near the rib 1e, that is, on both sides of the main plate, and both sides of the diaphragm blades are guided, so that the diaphragm device can be made compact. In addition, since the guide member is formed in an arc shape, the guide member comes into line contact with the blade, and the guide is smoothly performed.

Note that, as is clear from the above description, the present invention can be similarly implemented even when the guide member is provided on the side of the cover.

Next, a second embodiment of the present invention will be described with reference to FIGS. According to this embodiment, as shown in FIG. 8, the guide member 1d is provided with a step "l". This step acts as a spacer and prevents the diaphragm blades 4 and 5 from making surface contact with each other. Therefore, smoother guidance can be provided. In addition, since the guide member is provided with the step, the width of the aperture blades 4 and 5 is set to be large or small. The other elements are the same as those described with reference to FIGS. 1, 2 and 3, and thus are denoted by the same reference numerals and will not be described repeatedly.

[Effects of the Invention] As described above in detail, according to the present invention, the aperture blade does not require a long hole for guide, so that the width direction can be reduced. That is, the aperture device can be made small.
In addition, since there is no need to provide a long hole, especially compared to conventional ones that provide long holes in series, such as a slide type,
The length direction can also be shortened.

Further, the conventional aperture blade is provided with a long hole for guide, and the blade processing is relatively complicated. However, according to the present invention, since there is no long hole, the processing of the blade is also simplified.

[Brief description of the drawings]

FIGS. 1, 2 and 3 show a first embodiment of the present invention.
The figure is an exploded perspective view, FIG. 2 is a plan view without a cover,
3 is a sectional view taken along line AB in FIG. 2, FIGS. 4 and 5 show a second embodiment of the present invention, FIG. 4 is a plan view thereof, and FIG. 5 is a line FF in FIG. 6 to 10 are views showing a conventional example. FIGS. 6 and 8 are plan views showing swing type and slide type aperture devices, respectively. FIG. 7 is FIG. 6 or FIG. 9 is an exploded perspective view of a slide-type aperture device, and FIG. 10 is an exploded perspective view of the same viewed from the back. 1… diaphragm plate, 4, 5… diaphragm blade 6… cover, 1a, 1d… guide member

Claims (2)

(57) [Claims] An aperture base plate having an opening formed on an optical axis, and a diaphragm base plate movably supported by the base plate, moving in different directions to adjust the amount of light passing through the opening. A plurality of diaphragm blades, wherein the base plate is provided with a guide portion partially formed inward from both sides of the base plate, and the plurality of diaphragm blades are provided. The light amount diaphragm device according to claim 1, wherein the diaphragm blades are guided in the moving direction by contacting the guide members at both sides of the diaphragm blades when moving in different directions. 2. A light amount diaphragm device according to claim 1, wherein the guide member has a step formed to guide the plurality of diaphragm blades so as not to contact each other in the optical axis direction.