JPH08179399A - Shutter for camera - Google Patents

Abstract

PURPOSE: To obtain a shutter for a camera used also as a diaphragm whose number of parts is small, whose structure is simple and which hardly has such a possibility that 'light leakage' occurs. CONSTITUTION: In this shutter for a camera, a shutter unit 3 capable of moving in the optical axis direction is assembled in a lens barrel 1, and the opening amount of shutter blades 9A and 9B of the shutter unit 3 is regulated in accordance with the movement of the shutter unit 3 in the optical axis direction. The shutter is provided with an opening position regulating member 20 supported to move in the circumferential direction with respect to the shutter bottom board 5 of the shutter unit 3 and regulating the opening position of the shutter blades 9A and 9B in accordance with the position in the circumferential direction, and a cam means 22 on the inner surface of a lens barrel by which the member 20 is driven.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera shutter, and more particularly to a camera shutter in which the shutter blade can also serve as a diaphragm blade.

[0002]

2. Description of the Related Art Recently, in a compact camera or the like for performing aperture priority program control, the shutter blade for controlling the exposure time is stopped in the middle of opening without providing the aperture blade, and the shutter blade is also used as the aperture blade. Are known. That is, this structure is disclosed in, for example, Japanese Patent Laid-Open No.
As shown in JP-A-254428, JP-A-2-254431, and JP-A-3-90231, a photographing unit is attached to a shutter unit that is arranged in the lens barrel so as to be movable in the optical axis direction. The required aperture size is obtained by controlling the maximum open position of the shutter blades of the shutter unit according to the movement of the taking lens in the axial direction.

That is, in the lens shutter disclosed in Japanese Patent Laid-Open No. 2-254428, a zoom ring disposed around the shutter substrate is provided with a circumferential adjustment cam, and a regulating cam positioned on the shutter substrate is used as a shutter blade. Is engaged with an operating lever that opens and closes. In addition, JP-A-2-254431
In the camera shutter of the publication, a regulation ring is provided around a shutter base plate with a regulation adjustment cam parallel to the optical axis, and a shutter blade is opened and closed in a notch of the shutter base plate where the regulation cam is located. One end of the actuating lever is exposed, the maximum swing angle of the operating lever is regulated, and the maximum opening amount of the shutter blade is controlled.

In the camera shutter disclosed in Japanese Utility Model Laid-Open No. 3-90231, an F-ring whose rotation is controlled around the optical axis is located on the surface of the shutter substrate and passes through an arc-shaped long hole on the surface of the shutter substrate. The stopper boss of the F ring is introduced into the shutter substrate, and the maximum opening position of the shutter blade is controlled by the position of the stopper boss in the circumferential direction of the shutter blade, which is exposed to the range of movement of the shutter blade.

[0005]

However, these conventional diaphragm / shutter structures not only require a large number of parts and a complicated structure for controlling the opening position of the shutter blades, but also have a problem in the prior art. According to the structure of JP-A-254428, an annular gap having a considerable width is required between the zoom ring and the shutter substrate, and in the shutter of JP-A-2-254431, the shutter substrate on which the restriction cam is located is considerably large. It is necessary to make a large notch. Also,
According to the shutter disclosed in Japanese Utility Model Laid-Open No. 3-90231, an arcuate elongated hole in which a stopper boss is arranged must be formed in a shutter substrate. Therefore, according to these conventional positions, "light leakage" from annular gaps, notches, and arc-shaped slots.
There was a risk that this could occur, and there were many cases in which it was difficult to take measures against shading.

In view of the above-described problem of the diaphragm / shutter, an object of the present invention is to provide a camera shutter also for a diaphragm, which has a small number of parts, has a simple structure, and is less likely to cause "light leakage". To get.

[0007]

To achieve this object, according to the present invention, a shutter unit movable in the optical axis direction is incorporated in a lens barrel, and the shutter unit of the shutter unit is moved according to the movement of the shutter unit in the optical axis direction. In a camera shutter that regulates an opening amount of a shutter blade, an opening that is supported movably in a circumferential direction with respect to a shutter base plate of the shutter unit and that can regulate an opening position of the shutter blade according to a position in the circumferential direction. The present invention proposes a camera shutter including a position regulating member and a cam means on the inner surface of the lens barrel to which the open position regulating member is driven. According to a preferred embodiment of the present invention described later, the open position restricting member is capable of directly engaging the shutter blade to restrict the open position of the shutter blade and between the shutter base plate and the blade pressing base plate of the shutter unit. The cam means is a member movably positioned in an arc groove formed on the outer peripheral surface of the shutter base plate, and the driven projection of the open position restricting member protruding from the peripheral surface groove can follow the peripheral surface. Described as a cam groove.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. In FIGS. 1 to 5, a shutter unit 3 is mounted inside a cylindrical lens barrel 1 of the camera, the mounting state of which can be moved in the optical axis α direction of a photographic lens 2 described later. That is, the shutter unit 3 is assembled on the basis of the shutter base plate 5 and the blade pressing plate 6 each having the lens opening 4 formed at the center thereof, but the driven piece 5a is projected on a part of the outer peripheral surface of the shutter base plate 5. The driven piece 5a is guided in the longitudinal direction of the lens barrel 1 by the guide groove 7 formed on the inner peripheral surface of the lens barrel 1 and parallel to the optical axis α. Although a photographing lens 2 shown by an imaginary line in FIG. 1 is fixed to the central portion of the surface of the blade holding plate 6, the photographing lens 2 is provided with a shutter screw by a feed screw 8 penetrating the shutter base plate 5 and the blade holding plate 6. The movement is adjusted in the direction of the optical axis α together with 3, and an image is formed on a film surface (not shown).

The shutter unit 3 is provided with two shutter blades 9A and 9B incorporated in a flat space X formed between the shutter base plate 5 and the blade pressing plate 6, as shown in FIG. The bases of these shutter blades 9A and 9B are supported by the shutter base plate 5 so as to be capable of fan-shaped movement around the fulcrum pins 10A and 10B to open and close the lens opening 4. In addition, a drive motor 11, for example, a permanent magnet in this embodiment, is used as a rotor on the peripheral portion of the surface of the blade pressing plate 6,
Moving magnet type motor that arranges coils around
An actuator using a so-called iris motor is fixed by a motor mounting plate 12, and the rotor 1 of the drive motor 11 is fixed.
The drive pin 11b extending from 1a is exposed to the driven end portion 14a of the opening / closing lever 14 rotatably supported by the shutter base plate 5 by the support shaft 13. The drive pin 15 planted in the drive end portion 14b of the opening / closing lever 14 is inserted into the escape hole 16 of the blade pressing plate 6 shown in FIG.
The shutter blades 9A and 9B are inserted into the long holes 17 formed at the bases of the shutter blades 9A and 9B, and both shutter blades 9A and 9B are synchronously opened and closed by the rotation of the opening and closing lever 14. In addition,
In the drawings, reference numerals "18A, 18B" indicate each shutter blade 9
The shutter blades 9 are initial position stoppers that are exposed to the front end portions 9a of the A and 9B and that close the lens opening 4.
Although not shown, A and 9B are corresponding initial position stoppers 18A and 18B due to the magnetic attraction force between the rotor (permanent magnet) inside the drive motor and the auxiliary pole made of a magnetic material.
Take the locking position abutted against.

An arc groove 19 is formed on the inner surfaces of the shutter base plate 5 and the blade pressing plate 6 at a position facing the light shielding portion 9b of one shutter blade 9A, and the outer edge 9c of the light shielding portion 9b is formed in the arc groove 19. Both shutter blades 9A, 9B
The open position restricting member 20 that determines the maximum opening position of the above is slidably positioned along the arc groove 19. That is, the open position restricting member 20 has a driven protrusion 20a protruding toward the inner peripheral surface of the lens barrel 1 through the peripheral groove 21 formed on the outer peripheral surfaces of the shutter base plate 5 and the blade pressing plate 6, On the inner peripheral surface of the lens barrel 1 corresponding to the driven protrusion 20a, the open position regulating member 20 is formed in accordance with the movement of the shutter unit 3 in the optical axis α direction.
A circumferential cam groove 22 that determines the circumferential position of is formed. That is, as shown in FIG. 5, since the peripheral cam groove 22 on the inner peripheral surface of the lens barrel 1 is formed into a cam shape having an angle with respect to the length direction of the lens barrel 1, the image is taken by driving the feed screw 8. When the lens 2 and the shutter unit 3 are moved in the optical axis α direction with respect to the lens barrel 1, the open position regulating member 20 in the arc groove 19 is formed.
Is adjusted in the circumferential direction of the shutter base plate 5.

Since the camera shutter according to the illustrated embodiment has the above-described structure, when the camera is released, the photographing lens 2 and the shutter unit 3 are moved by the feed screw 8 with respect to the optical axis α with respect to the lens barrel 1. Direction, the focus is adjusted and the rotor 11a of the drive motor 11 is moved.
Will be rotated clockwise in FIG. 2 (counterclockwise in FIG. 3). Therefore, the open position restricting member 20 moves in the circumferential direction of the shutter base plate 5 along the circumferential cam groove 22 in accordance with the amount of movement of the shutter unit 3 in the optical axis α direction. When the aperture value is an intermediate value, the open position restricting member 20 is moved to the position shown in FIG.

Therefore, when both shutter blades 9A and 9B are opened by the opening / closing lever 14 by the excitation of the drive motor 11, the light shielding portion 9b of one shutter blade 9A is opened.
Since the outer edge 9c of the shutter is locked by the moved open position restricting member 20, both shutter blades 9A and 9B stop at the same half open position, maintain the aperture restricting position as shown in FIG. Become. Of course, this diaphragm state is maintained for a time controlled by a known exposure control means, and the drive motor 11 from the program mechanism is de-energized or the reverse energization causes the shutter blades 9A and 9B to move to the positions shown in FIGS. It returns to the closed state shown in 3.

FIG. 7 shows the open state of the shutter blades 9A and 9B when the program mechanism issues a command for the full open aperture state. As can be understood from FIG. 7, in this case, the open position regulating member 20 is the shutter. It can be understood that since the blades 9A and 9B are retracted out of the locus of movement, they do not come into contact with the light shielding portions 9b of the shutter blades 9A and 9B.

Further, in the camera shutter according to the illustrated embodiment, since the shutter blades 9A and 9B are directly controlled in position by the opening position restricting member 20, the number of parts is small and the mechanism is simple. Since the opening position restricting member 20 that is positionally controlled in the direction is incorporated between the shutter base plate 5 and the blade pressing plate 6, it is not necessary to form an opening such as an elongated hole on the surface of the shutter base plate 5 and the lens opening 4. , The structure does not require special consideration of "light leakage". Further, according to the structure of the illustrated embodiment, it is possible to obtain a compact aperture restriction mechanism which does not increase the outer diameter of the lens barrel.

[0015]

As is apparent from the above description, according to the present invention, there can be obtained a camera shutter having no groove or hole that penetrates the shutter base plate and blade holding plate of the shutter unit, and the shutter blade is a mirror. Since the position is directly controlled by the open position regulating member that follows the shutter blades of the barrel, the number of parts is small and the structure is simple.

[Brief description of drawings]

FIG. 1 is a cross-sectional view in the optical axis direction of a camera shutter according to the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a cross-sectional view of the camera shutter seen from below.

FIG. 4 is an enlarged cross-sectional view of a main part taken along line 4-4 of FIG.

FIG. 5 is an enlarged perspective view of a main part of the shutter for the camera showing a relationship between an open position restricting member and a peripheral cam groove.

FIG. 6 is a sectional view similar to FIG. 3, showing the shutter blades in a semi-open state.

FIG. 7 is a sectional view similar to FIG. 3, showing the shutter blades in a fully opened state.

[Explanation of symbols]

 1 lens barrel 2 photographing lens 3 shutter unit 4 lens opening 5 shutter base plate 6 blade holding plate 7 guide groove 8 feed screw 9A, 9B shutter blade 10 fulcrum pin 11 drive motor 12 motor mounting plate 13 spindle 14 opening / closing lever 15 drive pin 16 17 Long Hole 18A, B Stopper 19 Arc Groove 20 Open Position Restricting Member 20a Driven Protrusion 21 Circumferential Groove 22 Circumferential Cam Groove

Claims (3)

[Claims] 1. A shutter for a camera, wherein a shutter unit movable in an optical axis direction is incorporated in a lens barrel, and an opening amount of shutter blades of the shutter unit is regulated according to movement of the shutter unit in the optical axis direction. An open position restricting member that is movably supported in the circumferential direction with respect to the shutter base plate of the unit and that can restrict the open position of the shutter blades according to the position in the circumferential direction, and the open position restricting member is driven by the open position restricting member. A camera shutter, comprising: a cam means on the inner surface of the lens barrel. 2. The open position restricting member is capable of directly engaging with the shutter blade to restrict the open position of the shutter blade, and in an arc groove formed between the shutter base plate and the blade pressing base plate of the shutter unit. The camera shutter according to claim 1, wherein the shutter is positioned so as to be movable. 3. The cam means is a circumferential cam groove that can be driven by a driven projection of the open position restricting member that is projected from a circumferential groove on the outer peripheral surface of the shutter base plate. The camera shutter described.