JPH04133038A - Shutter used also as diaphragm for camera - Google Patents

Abstract

PURPOSE:To make an intermediate aperture nearly circular, to reduce the number of blades and to totally close the aperture by providing an extension part on at least one of plural blade members and covering the opening part of the center of an optical axis in a minimum stop state. CONSTITUTION:The extension parts 1c and 2c always positioned on the outer side than the interior diameter of the opening part of a vane wheel 8 and a ring 7 are provided on the blades 1 and 2. 1st cam grooves 8a-8c and 2nd cam grooves 8a2-8a3 in which the pins 1b-6b of the blades 1-6 are fitted so as to freely slide are provided on the vane wheel 8. Then, the change from a stop aperture minimum position to a totally closing position is given to the blade 1 by areas 8a2-8a3 provided successively to the areas 8a1-8a2 of the cam groove 8a, and only the blade 1 is turned toward the center of the optical axis 0 from the minimum stop position to make the stop aperture is made in the totally closed state. Namely, the blade 1 turns until it is positioned at the end 8a3 of the cam groove 8 to cover the minimum stop aperture A2 part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a camera aperture shutter, and more particularly, to a camera aperture shutter that can also serve as an aperture function.

[Prior Art] Many proposals have been made regarding a lens shutter mechanism that also serves as an aperture function of a camera, or a similar sector mechanism. For example, the lens shutter mechanism presented in the Photo Encyclopedia Volume 5 (Kodansha edition, December 5, 1980, pages 71-74) is a general shutter mechanism consisting of five blades.

Further, an improved two-blade shutter for cameras disclosed in Japanese Utility Model Publication No. 46-20534 relates to a lens shutter that is composed of two blades and also serves as an aperture for a compact camera.

Furthermore, a device for controlling light beams passing through a lens disclosed in Japanese Utility Model Publication No. 47-4379 relates to an iris diaphragm consisting of a large number of blades or a sector mechanism that can be used as a lens shutter.

Further, the aperture device disclosed in Japanese Utility Model Application Publication No. 51-40221 is related to an aperture device equipped with one or more aperture blades, and when the aperture is further narrowed down than the minimum aperture, a neutral density filter is used. A blade with this function covers the above-mentioned minimum aperture and adjusts the amount of light. If the light transmittance of the filter is set to 0, it is possible to achieve a fully closed state.

[Problems to be Solved by the Invention] However, each of the above-mentioned conventional mechanisms has a number of problems when used as an aperture and shutter. . In other words, in the lens shutter mechanism presented in Volume 5 of the aforementioned Encyclopedia of Photography, only the fully open and fully closed apertures are considered, but the aperture shape during the aperture operation is star-shaped; It is a difficult mechanism to use as an aperture mechanism.

In addition, 2 disclosed in the above-mentioned Utility Model Publication No. 46-20534
In a single blade type shutter, the aperture aperture shape of the shutter cannot be said to be circular, but rather is close to a diamond shape. Therefore, the blur that appears in photographs taken with a camera incorporating this shutter mechanism is diamond-shaped, which is undesirable. Furthermore, compared to apertures with circular apertures, since the light flux around the lens is used, there is also the problem that more aberrations appear.

Further, in the device disclosed in the above-mentioned Japanese Utility Model Publication No. 47-4379, the aperture shape of the intermediate diaphragm of the sector mechanism is approximately circular, but since the blades overlap each other, it is difficult to fully close the aperture. was difficult.

Furthermore, the diaphragm device disclosed in the above-mentioned Japanese Utility Model Publication No. 51-40221 requires special blades for covering the minimum aperture in addition to the blades for the normal diaphragm mechanism. As a result, when used in a shutter or the like, the blades act as additional inertia, worsening responsiveness. Furthermore, there were other problems such as the need to provide a dedicated cam groove for driving the dedicated blade.

An object of the present invention is to solve the above-mentioned problems by providing an aperture at the center of the optical axis in a minimum diaphragm state using at least one blade member among the plurality of blade members in a shutter that also serves as an aperture consisting of a plurality of blade members. The intermediate diaphragm aperture also has a nearly circular shape, and the aperture can be fully closed.Furthermore, the number of blades that make up the shutter is small, and the shutter operation is reliable. To provide shutters.

[Means and effects for solving the problems] The camera diaphragm shutter of the present invention has a plurality of blade members arranged around the optical axis, and each blade member has a first and a second fulcrum and at least the above-mentioned fulcrum. and a cam member having a first cam groove that fits into either one of the first or second fulcrum and moves the fulcrum, wherein the cam member is provided on at least one of the plurality of blade members. a blade that is connected to a first cam groove of the cam member that fits into a fulcrum of the blade member having the extended portion, and has the extended portion when the blade member is in a minimum aperture state; The member has a second cam groove shaped to cover the center of the optical axis, and the plurality of blade members provide an aperture aperture, and when the shirt shirt is closed, the minimum aperture opening is formed by the blades having the extending portion. It is designed to be covered by a member.

[Example] The present invention will be described below based on illustrated embodiments.

FIG. 1 is an exploded perspective view of an aperture-shutter of a camera showing an embodiment of the present invention. As shown in this figure, the shutter has six blades 1. 2
．． 3.4. 5. 6, a ring 7, a arrow wheel 8 which is a cam member, and a seat 9.

Among the blades 1 to 6, blades 1 and 2 have an A-type shape, and the other blades 3 to 6 have a B-type shape. A above
The blade of this type is always in arrow 8 regardless of the narrowing operation.
and an extending portion 1c located outside the inner diameter of the opening of the ring 7.
, 2c are provided, and the B type is not provided with the above-mentioned extending portion.

FIG. 2 is a perspective view showing the shapes of type A and type B blades. As shown in this figure, the A-type blade is longer than the B-type blade by the length of its extensions IC and 2C. In addition, the blades 1 to 6 of type A and B both have the first fulcrum points 1a to 6a disposed on their upper surfaces, and the second fulcrums 1b to 6b disposed on their lower surfaces. has been done.

Six holes 7a are provided in the ring 7 at 60° intervals, and the bottles 1a to 6a of the blades 1 to 6 are arranged in la, 2
a, . . . , 5a, and 6a are rotatably fitted in this order. In addition, the bottle 4a of the blades 4 and 5.

5a into the ring 7 and attach it, the above-mentioned bottle 4a
, 5a into the holes 9a and 9b, and the sheet 9 is sandwiched and assembled.

Further, in the A-type blade 1, at the same time that the bottle 1a is fitted into the hole 7a of the ring 7, the extending portion IC is slidably inserted between the sheet 9 and the ring 7. And, the tip of the extension IC is always
The ring 7 remains in contact with the surfaces of the sheet 9.

Therefore, collision of the blade 1 with the stepped portion of the blades 4, 5 or 5, 6 is prevented.

Similarly, the A-type blade 2 has its extended portion 2C slidably inserted into the lower surface of the blade 6 to prevent it from falling off from the blade 6 during aperture operation, and to It also prevents warping.

The arrow wheel 8 has first cam grooves 8a to 8c and second cam grooves g into which the bins 1b to 6b of the blades 1 to 6 are slidably fitted.
a 3 a s is provided, and furthermore, a circular opening 8 d corresponding to the open aperture centered on the optical axis 0 is provided in the center of the arrow wheel 8 .

The blades 1 to 1 are rotatably supported by the ring 7.
The arrow wheel 8 is placed on the lower surface of the cam groove 8a, 8b, 8c.
Assemble by fitting the bottles 1b to 6b into contact with each other. In addition, the fitting combination of the cam groove and the bottle is the above cam groove 8.
The pin 1b of the blade 1 is fitted into the cam groove 8b, the pin 2b of the blade 2 is fitted into the cam groove 8b, and the blades 3, 4, . 5. 6 bins 3b, 4b, 5b, 6
b is inserted.

This shutter assembled as described above can be assembled by rotating the arrow wheel 8 in the R direction, so that each of the blades 1 to 6 bins 1b to
6b slides along cam grooves 8a, 8b, and 8C, respectively. The blades 1 to 6 are mounted on the cam grooves 8a with the pins 1a to 6a fitted into the holes 7a of the ring 7 as fulcrums.
The blades 1 to 6 rotate based on the trajectory of ~8C, and the blades 1 to 6 rotate from the aperture aperture open position to the aperture aperture minimum position, and further, only the blade 1 rotates to the aperture aperture fully closed position.

The above-mentioned calibration positions of the blades 1 to 6 are each cam groove 3a.

It is given by the shapes of 3b and 3c. That is, feather 1~
The open aperture position of 6 is at the end 8 a of each cam groove.
i , 8 b t , 8 c 1.

Further, the change from the aperture open position to the minimum position is given by the ga 3 a 2 region, the 8b1-8b2 region, and the 8 c 18 C2 region in the middle of the cam groove.

The cam curve of the cam groove has a locus that gradually approaches the optical axis O direction. Therefore, each of the blades 1 to 6 is rotated in the direction of the optical axis O by the aperture operation, and the aperture diameter is gradually narrowed down until it becomes the minimum aperture diameter.

Furthermore, the change from the minimum aperture diameter position to the fully closed position is caused by the region 8a - 8a of the cam groove 8a for the blade 1.
2 is a second cam groove connected to the second cam groove.

The cam groove shape has a cam curve that approaches the optical axis O, and as the arrow wheel 8 further rotates in the R direction, only the blade 1 rotates from the minimum aperture position toward the center of the optical axis O. , fully close the aperture. On the other hand, for blades 2 to 6 other than the above, the cam groove end portion 8 b 2
It is given by the 8 b 3 area and the 8 c - 8 c3 area, but since the cam trajectory in this area is an arc centered on the optical axis O, the blades 2 to 6 do not rotate and the state of the minimum aperture aperture is maintained. be done.

The operating state of the diaphragm/shutter of this embodiment constructed as above will be explained with reference to FIGS. 3 to 8.

FIG. 3 shows an exploded perspective view of the aperture in an open state, and the opening 8d of the arrow wheel 8 has an open aperture A. is formed. Here, the tip of the extending portion 1c of the blade 1 is on the sheet 9,
As mentioned above, smooth rotation of the blade 1 is ensured, and at the same time, warping of the blade is prevented. The extending portion 2c of the blade 2 is also inserted between the blade 6 and the arrow wheel 8, so that the same smooth rotational movement is achieved, and at the same time, the blade is prevented from warping. In addition, even in other aperture states and fully open states, the tips of the extension parts IC and 2C of the blades 1 and 2 are always inserted and slid onto the sheet 9 or the surface of the blade 6, as described above. shall be.

FIG. 4 shows a perspective view of the present Nyatta in an intermediate aperture state. Note that the ring 7 is omitted from the illustration. As shown in this figure, when the arrow wheel 8 is rotated by a predetermined angle in the R direction, each blade 1
- 6 are rotated to the intermediate aperture position by the cam grooves 8a8b and 8c, respectively, and set to the intermediate aperture diameter A1.

FIG. 5 shows a perspective view of the present shutter in the minimum aperture state. Each of the blades 1 to 6 is rotated to the minimum aperture position and is in the state of the minimum aperture diameter A2.

Note that FIG. 6 shows a plan view of the shutter in the same minimum aperture state, but as shown in this figure, the blade size is 1°2.
b and 2b are located in the 8 a 28 b 2 parts of the cam groove of the arrow wheel 8. Although not shown, the blades 3 to 6
The bins 3b to 6b are also located in the 8C2 portion of the cam groove.

FIG. 7 is a perspective view of the fully open state in which the aperture is further rotated in the R direction from the minimum aperture state to cover the minimum aperture diameter A2 portion with the blades 1. FIG. 8 shows a plan view of the fully closed state, in which the blade 1 has been rotated to a position where it is located at the end of the cam groove 8, 8a, and covers the minimum aperture diameter. .

However, the other blades 2 to 6 are held at the minimum aperture state.

In the dual embodiment, the ring 7 is fixed to the lens frame and the arrow wheel 8 is rotated, but the arrow wheel 8 may be fixed and the ring 7 is rotated. In addition, in the embodiment, a cam groove for driving the blades was provided in the arrow wheel 8, but
The arrow wheel 8 may be provided with a driving pin, and each blade may be provided with a cam groove.

Furthermore, the regions of cam grooves 8b-8b3 and 8C28C3 into which the pins 2b to 6b of the blades 2 to 6 of the arrow wheel 8 fit have loci of the same radius with respect to the optical axis O in the example, but the blades The cam locus may be such that the cam rotates further toward the inner diameter within a range that does not hinder the movement of the cam. Furthermore, in the embodiment, two types of blades, the A and B types, are used as the plurality of blade shapes, but the present shutter may be configured with all the blades being of the A type.

[Effects of the Invention] As described above, in the diaphragm shutter of the present invention, in the diaphragm mechanism constituted by a plurality of blade members, at least one blade is provided with an extension, and the blade is used to adjust the minimum diaphragm aperture. Since the fully closed state was obtained by covering the
According to the present invention, since the blades having the diaphragm function also have the diaphragm fully closing function, the number of blades required may be small. Also,
After the aperture is set to the minimum aperture, the aperture is fully opened, resulting in good bokeh. Furthermore, it is possible to obtain a nearly circular aperture in each aperture state, and it is possible to provide a shutter that also serves as an aperture and has remarkable effects such as having a lens shutter function.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a shutter that also serves as an aperture according to an embodiment of the present invention. FIG. 2 is a perspective view that shows the shape of the blades used in the shutter that also serves as an aperture shown in FIG. FIG. 4 is an exploded perspective view of the diaphragm/shutter in the aperture opening state shown in FIG. 1, FIG. 4 is a perspective view of the diaphragm/shutter in FIG. FIG. 1 is a perspective view and a plan view of the diaphragm/shutter in the minimum aperture state, and FIGS. 7 and 8 are a perspective view and a plan view of the diaphragm/shutter in the fully closed state of FIG. 1, respectively. . 1 to 6・・・・・・・・・Feather (feather member) 1a
~6a...Bin (first fulcrum) 1b~6b...
...Bin (second fulcrum) lc, 2c...Blade extension 8...Corner wheel 8a to 8C.
...Cam groove (first cam groove) 8a - 8a3.
...Cam groove end (second cam groove) 1.2, 3, 4
, 5.6 feather + kon (side lishibaai p o sai) Ia, 2a, 3
o, 4a, 5a, 6a Shin (first fulcrum) +b, 2b, 3b, 4b, 5b, 6b Shiri (fulcrum of pigeon 2) lc, 2a Hazukitabe 8 Yashin (cam 111 left) ) 8a, 8b, 8c cam; A (!F, l cam groove) 802
-803 cam jL Kokushin (Invitation 2 cam groove)

Claims (1)

[Claims] (1) A plurality of blade members are arranged around the optical axis, and each blade member is fitted with a first and second fulcrum, and at least one of the first or second fulcrum, and this fulcrum is moved. and a cam member having a first cam groove, an extension portion provided on at least one of the plurality of blade members, and a fulcrum of the blade member having the extension portion; a second cam groove connected to the first cam groove of the cam member to be fitted and having a shape such that the blade member having the extending portion covers the center of the optical axis when the blade member is in a minimum aperture state; A shutter that also serves as an aperture for a camera.