JP2559958Y2 - Iris device for interchangeable lenses - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm device for a photographic interchangeable lens.

[0002]

2. Description of the Related Art Conventionally, some zoom lenses and macro lenses maintain a constant open F value by changing the aperture diameter in conjunction with zooming or focusing, or minimize a change in the open F value. Many. As a diaphragm device for this purpose, Japanese Patent Application No. 1-290 filed by the present applicant has been proposed.
No. 80 (Japanese Utility Model Laid-Open No. 2-121729) has been proposed. Hereinafter, the aperture device will be described with reference to FIG.

In FIG. 3, pins 12b of a plurality of aperture blades 12 forming aperture openings are respectively fitted into a plurality of cam holes 11a provided in the aperture blade drive member 11, while pins 12a of the aperture blades 12 are fitted. Are pivotally attached to holes provided in a lens moving frame (not shown) of the interchangeable lens. Then, when the diaphragm blade driving member 11 is rotated in the counterclockwise direction in the figure, the diaphragm blade 12 is rotated in a predetermined direction, and the diaphragm aperture is in a narrowed state. Here, the diaphragm blade driving member 11 is urged clockwise by a tension spring (first urging means) 23 attached between the protrusion 11d and the lens moving frame, whereby the protrusions 11b and 11c are narrowed down. The arm 18a of the lever 18 and the F
It is engaged with the value correction odor distribution surface 21a.

The ring 18b of the aperture lever 18 is rotatably held in a groove 5d (FIG. 4) of the fixed lens barrel 5 of the interchangeable lens, and a projection 18c provided on the ring 18b and the fixed lens barrel 5 Tension spring (second biasing means) mounted between
20, the aperture lever 18 is urged in the counterclockwise direction in the figure. Reference numeral 24 denotes an annular ring attached to the lens moving frame near the diaphragm blade driving member 11, and a tension spring (third urging means) mounted between the projection 24b and the lens moving frame. 25, the protrusion 24c is pushed by the arm 1
8a.

When the lens moving frame moves rightward (wide-angle side) in the figure by zooming, the diaphragm blade driving member 11 and the ring 24 move together in the same direction, and the diaphragm blade driving member 11 moves to the F value correction gradient surface 21a. As a result, it is rotated counterclockwise through the protrusion 11d. Thereby, the aperture blade 12
The F-number is corrected by narrowing the aperture opening formed by.
When the aperture setting lever 19 on the camera side rotates the aperture stop lever 18 in the counterclockwise direction, the arm 18a rotates the aperture blade driving member 11 in the same direction, whereby the aperture opening is set in the aperture state. .

FIG. 4 shows the attitude of the stop-down lever 18 when the stop setting lever 19 on the camera side is operated. The squeezing lever 18 is provided with a biasing force of a tension spring 20,
The reaction force of the aperture setting lever 19, the reaction force of the groove 5d provided in the fixed lens barrel 5, and the S of the drawing caused by the tension spring 23.
A clockwise biasing force P about the point and a tension spring 2
5 receives a biasing force Q in the counterclockwise direction around the point S in the figure. Assuming that the points where the urging forces P and Q act on the arm 18a and the distance between the ring 18b are L and M, respectively, if the distances L and M are extremely long, the point S acts on the aperture lever 18 The moment of the surrounding force is P
× L and Q × M.

The moments P × L and Q × M are set such that P × L <Q × M, and the stop-down lever 18 is always in the position shown in FIG. Maintain a downward-sloping posture like this. Therefore, aperture setting lever 1
The contact position between the arm 18a and the projection 11b with respect to the position 9 is not changed and is always constant, so that it is possible to suppress a control error of the aperture diameter during the forward movement and the backward movement.

[0008]

By the way, in the above-described configuration, in order to stabilize the posture of the aperture-down lever 18 in a state of lowering to the left, the urging force Q in FIG. Need to be bigger. However, if the biasing force Q is increased too much, S
At the point and the point T, the stop-down lever 18 is operated while the ring 18b is in strong contact with the fixed lens barrel 5, and
Problems such as deterioration of the operation condition of the narrowing lever 18 and deterioration of the durability become problems. If the urging force Q is set to a predetermined value or more, the operation of the aperture setting lever 19 on the camera body may be hindered.

The present invention has been made in view of such a conventional problem, and has a conventional function of stabilizing the position of the stop-down lever during reciprocating operation of the stop setting lever and eliminating a stop diameter control error. It is an object of the present invention to obtain a diaphragm device which can keep the urging force Q small without deteriorating the operation, and which secures a good operation condition and durability of the diaphragm lever.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2 showing an embodiment, the present invention is directed to a plurality of diaphragm blades 12 forming a diaphragm aperture and a lens optical axis 9 (FIG. 2).
A diaphragm blade driving member 11 that is held by a lens moving frame 10 that can move in the direction and that drives a diaphragm blade 12 by rotating about an optical axis to change the size of the diaphragm opening, and a diaphragm that opens the diaphragm opening First urging means 23 for urging the blade driving member 11, F-number correcting means 21 for operating the diaphragm blade driving member 11 in conjunction with the movement of the lens in the direction of the optical axis 9 and correcting the aperture opening; Aperture setting lever 1 on camera side
9 has an engagement portion 18c capable of engaging with the aperture setting lever 1
Aperture stop lever 18 for driving the aperture blade driving member 11 in conjunction with the movement of the shutter 9; and second urging means mounted near the end of the aperture stop lever 18 for urging the aperture stop lever 18 in the direction of narrowing the aperture opening. 20 and an engaging portion 2 which is held by the lens moving frame 10 in the vicinity of the diaphragm blade driving member 11 so as to be rotatable around the optical axis 9 and engages with the aperture stop lever 18.
4c, and a third urging means 25 attached between the rotating member 24 and the lens moving frame 10. The third urging means 25 is provided via the rotating member 24. The aperture lever 18 is moved in the direction in which the aperture opening is narrowed.
The present invention is applied to a stop device of an interchangeable lens configured to urge the lens. Then, the first urging means 23 is mounted between the diaphragm blade driving member 11 and the rotating member 24, thereby solving the above-mentioned problem.

[0011]

Since the first urging means is attached between the diaphragm blade driving member and the rotating member, the urging force of the first urging means is reduced by the diaphragm blade driving member and the stop-down lever. Internal force can be generated in the system of the rotating member 18 and the rotating member 24. Therefore, as described above, the rotating member 2
When the aperture 4 is provided near the aperture blade driving member 11 (when the distances L and M in FIG. 4 are close to each other), the posture of the aperture lever 18 is hardly affected by the urging force of the first urging means 23. There is no influence, and therefore, even if the urging force (Q in FIG. 4) of the third urging means 25 is made smaller than in the prior art, the posture of the aperture-down lever 18 can be stabilized in a state of lowering to the left.

In the section of the means for solving the above-mentioned problem and the operation which explain the configuration of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0013]

1 and 2, an embodiment of the present invention will be described. FIG. 2 is a sectional view showing an interchangeable lens provided with the diaphragm device according to the present invention. The interchangeable lens 1 is a zoom lens having a front lens group 2 and a rear lens 3, and the state illustrated in FIG. 2 is a wide-angle state. By rotating the zoom operation ring 4 from this state, the lens group moves to the telephoto side, that is, zooming is performed.

Reference numeral 5 denotes a fixed lens barrel. An aperture lever 18 constituting an aperture device 100 (FIG. 1) is rotatably held in a groove 5d of the fixed lens barrel 5, and its arm 18a is moved in the optical axis direction. Extends. A base end of an opening limiting plate 21 extending in the optical axis direction is attached to the fixed lens barrel 5 with a screw 22. The zoom operation ring 4 rotatably fitted to the fixed lens barrel 5 around the optical axis 9 is connected to a cam ring 6 by a connecting member (not shown). When the zoom operation ring 4 is rotated, the cam ring 6 is also rotated. At the same time, they rotate in the same direction. On the cam ring 6, a piece 7 is engaged with a circumferential groove 5a formed in the fixed lens barrel 5.
Are fixed by screws 8, whereby the cam ring 6 does not move in the direction of the optical axis 9 but performs only a rotational movement about the optical axis 9.

Reference numeral 10 denotes a lens moving frame movable in the direction of the optical axis. The lens moving frame 10 holds the rear lens group 3 and also includes a diaphragm blade 12 and a diaphragm blade driving member constituting the diaphragm device 100. 11 and a ring 24 are attached. Also, the pins 13 implanted in the lens moving frame 10
Are straight grooves 5b provided in the fixed lens barrel 5 in the direction of the optical axis 9;
And a cam groove 6 a provided in the cam ring 6. The cam groove 6 a is formed so that the lens moving frame 10 moves straight back and forth in the direction of the optical axis 9 by the rotation of the cam ring 6.

Further, a pin 14 is implanted in the cam ring 6,
The pin 14 passes through a hole 5 c provided in the fixed lens barrel 5 and is fitted into a cam groove 16 a provided in the cam ring 16. The pin 15 implanted in the fixed lens barrel 5 is connected to the cam ring 1.
6 is fitted into a rectilinear groove 16b in the direction of the optical axis 9 provided in the optical axis 6. When the cam ring 6 rotates, the cam ring 16 moves straight back and forth by the engagement between the pin 14 and the cam groove 16a.
The lens frame 17 holding the front lens group 2 is screwed and fixed to the cam ring 16 by a helicoid screw 17a, and the lens frame 17 also moves straight back and forth in the direction of the optical axis 9 by moving the cam ring 16 straight back and forth. Here, by zooming to the telephoto side, the rear lens group 3 moves in the direction of arrow A and the front lens group 2 moves in the direction of arrow B to the positions indicated by the two-dot chain lines.

Next, the configuration of the aperture driving device 100 will be described with reference to FIG. The same parts as those in FIG. 3 are denoted by the same reference numerals. In FIG. 1, a diaphragm blade driving member 11 supported by the lens moving frame 10 has an annular shape having an opening in the center, and has three projections 11b, 11c, 11d is formed,
In the annular portion, a plurality of cam holes 11a are provided at equal intervals. The pins 12b of the aperture blades 12 are respectively fitted into the plurality of cam holes 11a, while the pins 12a of the aperture blades 12 are inserted into holes (not shown) provided in the lens moving frame 10 (FIG. 2). Each is pivoted.

By rotating the diaphragm blade driving member 11, each diaphragm blade 12 rotates around the pin 12a. The plurality of diaphragm blades 12 form a diaphragm opening, and when the diaphragm blade driving member 11 is rotated in the counterclockwise direction in the drawing, the diaphragm blades 12 are turned into a narrowed state by rotation of the respective diaphragm blades 12.

The tension spring 23 has one end fixed to the projection 11d of the diaphragm blade driving member 11 and the other end fixed to the arm 24d of the ring 24, and biases the diaphragm blade driving member 11 clockwise in FIG. Then, the aperture opening works to open. The projection 11c can be engaged with the F-value correction odor distribution surface 21a of the opening restriction plate 21 fixed to the fixed lens barrel 5, and the projection 11b is
8a.

The squeezing lever 18 is connected to the arm 18a,
The ring 18b includes a ring 18b and a projection 18c.
As described above, it is attached to the groove 5d of the fixed lens barrel 5 so as to be rotatable around the optical axis 9. One end of a tension spring 20 attached to the fixed lens barrel 5 is attached to the projection 18c, whereby the aperture lever 18 is urged in a counterclockwise direction in the drawing, that is, in a direction to narrow the aperture. Further, the projection 18c can be engaged with an aperture setting lever 19 on the camera body side, and the aperture stop lever 18 rotates in conjunction with the operation of the aperture setting lever 19.

The ring 24 is arranged near the diaphragm blade driving member 11, and is rotatably attached to the lens moving frame 10 through an opening 24a. Here, the fact that the ring 24 is arranged in the vicinity of the diaphragm blade driving member 11 means that FIG.
Indicate that the distances L and M shown in FIG. On the outer periphery of the ring 24, two projections 24b, 24c and an arm 24d extending in the radial direction are formed.
One end of a tension spring 25 is fixed to b, and the other end of the tension spring 25 is fixed to the lens moving frame 10. Therefore, the ring 24 is urged in the counterclockwise direction in the figure by the urging force of the tension spring 25, and the projection 24c of the ring 24
The narrowing lever 18 is adapted to engage with the arm 18a of the narrowing lever 18, whereby the narrowing lever 18 is moved counterclockwise,
That is, the aperture is urged in the direction in which the aperture is narrowed. The other end of the tension spring 23 is fixed to the arm 24d.

FIG. 1 shows a state in which the interchangeable lens 1 is at the telephoto end. In this state, when the zoom operation ring 4 (FIG. 2) is operated to set a wide angle state, the lens moving frame 10 moves the optical axis 9. , The diaphragm blade driving member 11 and the ring 24 move integrally to the right in FIG. In conjunction with this, the aperture blade driving member 11 is moved to the F value correction gradient surface 21a.
As a result, the shutter 11 rotates counterclockwise through the protrusion 11c, thereby narrowing the aperture and correcting the F value. When the stop-down lever 18 is turned counterclockwise through the projection 18c by the stop setting lever 19 on the camera body side, the stop blade driving member 11 turns counterclockwise, whereby the stop opening is brought into the stop-down state. Become.

Here, as described above, the tension spring 23 is connected to the protrusion 11d of the diaphragm blade driving member 11 and the arm 24d of the ring 24.
, The urging force of the tension spring 23 is applied to the aperture blade driving member 11, the aperture lever 18, and the ring 2
4 will be internalized in the system. Therefore, in the case of the above-described configuration in which the distances L and M in FIG. 4 are close to each other, the posture of the aperture-down lever 18 is hardly affected by the urging force of the tension spring 23, and therefore the tension spring 25
Can be set without considering the effect of the biasing force P of the tension spring 23. That is, the urging force Q of the tension spring 25
Is smaller than in the prior art, the posture of the aperture-down lever 18 can be stabilized in a state of lowering to the left.

In the configuration of the above embodiment, the tension spring 2
Reference numeral 3 denotes a first urging means, an opening limiting plate 21 serves as an F value correcting means, a tension spring 20 serves as a second urging means, a ring 24 serves as a rotating member, and a tension spring 25 serves as a third biasing means. Each of the biasing means 25 is constituted.

In the above description, the zoom lens has been described. However, the present invention can be applied to a macro lens having a large lens driving amount by focusing.

[0026]

According to the present invention, the first urging means for urging the diaphragm blade driving member in a direction to open the diaphragm opening is constituted by the diaphragm blade driving member and the rotating member (in the vicinity of the diaphragm blade driving member). The biasing force of the first biasing means can be made to be an internal force in the system of the diaphragm blade driving member, the narrowing-down lever, and the rotating member, and the first biasing means is provided. Can hardly affect the posture of the stop-down lever. Therefore, the third
Even if the urging force (Q of FIG. 4) of the urging means (urging the aperture lever in the direction of narrowing the aperture opening) is made smaller than before, the posture of the aperture lever can be stabilized in a state of lowering to the left. As a result, the aperture stop lever can be smoothly driven without impairing the conventional function of eliminating the aperture diameter control error. As a result, the operating condition and durability of the aperture lever can be improved, and the operation of the aperture lever by the aperture setting lever on the camera body side is not hindered.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a diaphragm device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an interchangeable lens provided with the diaphragm device.

FIG. 3 is a perspective view showing a configuration of a conventional diaphragm device.

FIG. 4 is an explanatory diagram for explaining a force acting on a stop-down lever.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Interchangeable lens 5 Fixed lens barrel 10 Lens moving frame 11 Aperture blade drive member 12 Aperture blade 18 Aperture lever 19 Aperture setting lever 20, 23, 25 Tension spring 21 Opening restriction plate 24 Ring 100 Aperture device

Continuation of the front page (56) References JP-A-60-118813 (JP, A) JP-A 62-184536 (JP, U) JP-A 1-171428 (JP, U) JP-A 58-50408 (JP , U) Japanese Utility Model Showa 60-65727 (JP, U) Japanese Utility Model Showa 53-123933 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] A plurality of diaphragm blades forming a diaphragm opening;
It is held by a lens moving frame that can move in the lens optical axis direction,
A diaphragm blade driving member that changes the size of the diaphragm opening by driving the diaphragm blade by rotating about the optical axis, and a first bias that biases the diaphragm blade driving member in a direction to open the diaphragm opening. Means, an F-number correcting means for operating the aperture blade driving member in conjunction with the movement of the lens in the optical axis direction, and correcting the aperture opening, and an engaging portion engageable with an aperture setting lever on the camera body side A stop lever that drives the stop blade driving member in conjunction with the movement of the stop setting lever; and a stop mounted near the end of the stop lever for urging the stop lever in a direction to stop the stop opening. Second
A rotating member having an engaging portion that is held by the lens moving frame so as to be rotatable around the optical axis in the vicinity of the diaphragm blade driving member and engages with the aperture lever. A third urging means mounted between the member and the lens moving frame, wherein the aperture lever is moved in a direction in which the aperture opening is narrowed by the third urging means via the rotating member. A diaphragm device for an interchangeable lens, wherein the first urging means is mounted between the diaphragm blade driving member and the rotating member.