JPH08313969A - Light shielding device - Google Patents

Abstract

PURPOSE: To provide a light shielding device which is constituted so that the aperture accuracy of an aperture part is excellently secured in an open state and which contributes to the miniaturization of an applied photographing optical system. CONSTITUTION: This light shielding device is provided with plural inner blades 17b and 17c opened and closed by being turned around a prescribed shaft, plural outer blades 17a and 17d opened and closed by being turned around the prescribed shaft for shielding at least the light of luminous flux near an optical axis among the photographing luminous flux transmitted through the photographing optical system when they are closed and retreated from the transmitting path of the photographing luminous flux when they are opened, an open aperture part varying ring 15 being a position regulation means regulating the positions of the blades 17a and 17d when they are opened and changing the positions by interlocking with the variable power action of the photographing optical system for mainly shielding the light of the peripheral luminous flux among the photographing luminous flux transmitted through the photographing optical system when they are closed, retreated from the transmitting path of the photographing luminous flux and almost superposed on the respective blades 17b and 17c when they are opened and.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-shielding device, and more particularly to a light-shielding device that shields or opens an opening of a photographing optical system.

[0002]

2. Description of the Related Art Conventionally, in a small camera or the like for taking a picture, a drive lever for opening and closing a light-shielding blade has been used.
A lens shutter mechanism in which two light-shielding blades are opened and closed at the same time and a predetermined opening is formed by the inner edges of the two light-shielding blades has been generally put into practical use.

Further, by applying three or more light-shielding blades, the retracting space of the light-shielding blades can be made smaller than the size of the opening of the plurality of light-shielding blades when they are fully opened (open state). Various proposals have been made for a shutter mechanism that is downsized and the opening shape is improved.

For example, the shading blade device disclosed in Japanese Utility Model Publication No. 6-37400 is such that the shape of the opening is made into a polygonal shape close to a circular shape by three shading blades.

Further, the shutter mechanism disclosed in JP-A-64-526 discloses two inner blades which mainly shield the light beam near the optical axis of the opening of the photographing optical system, and the above-mentioned opening. By providing four light-shielding blades of two outer blades that mainly shield the light flux in the peripheral portion so as to shield the openings, the light-shielding blades are downsized and the light-shielding blades are fully opened. The storage space at that time is reduced and the shutter mechanism itself is downsized.

On the other hand, in recent years, a so-called zoom lens having a function of changing the photographing magnification has been generally put into practical use in a small camera or the like, and in such a zoom lens or the like, a camera, a lens or the like is used. A lens design is performed in consideration of miniaturization.

In the above zoom lens and the like, in general, the same open aperture area (area of the aperture when opened) is
On the short focus side, the open F value tends to be small (that is, the lens is bright), and on the long focus side, the open F value tends to be large (that is, the lens is dark).

Therefore, when designing the zoom lens or the like, first, the opening area at the time of opening is determined in order to secure the brightness of the lens (smaller opening F value) on the long focus side. Becomes As described above, the open F value tends to be smaller on the short focus side as compared with the case where the zoom lens or the like forming the photographing optical system is set on the long focus side. Bright lens)
However, in this case, it tends to be difficult to secure the resolution performance of the photographing optical system.

Therefore, when the zoom lens of the photographing optical system is in the open state on the short focal point side, the light shielding blade is not completely retracted to the outside of the opening so that the opening is not covered by the light shielding blade. The opening area of the opening can be changed between the case of being on the long focus side and the case of being on the short focus side by being formed by both the inner edge portion or the inner edge portion of the light shielding blade and the opening portion. Conceivable.

In other words, in this case, the relationship is such that the opening area on the short focus side at the time of opening <the opening area on the long focus side at the time of opening. Then, it is possible to improve the resolution performance of the photographic optical system by setting the open F value on the short focus side to be slightly large.

In such a case, it becomes necessary to change the open state of the light shielding device in association with the zooming operation of the photographing optical system.

Therefore, by changing the position of the opening-side stopper portion of the drive lever for opening and closing the light-shielding blade in conjunction with the zooming operation, the area of the opening portion in the open state is changed. Various proposals have been made for a zoom interlocking variable aperture light-shielding device.

By the way, when the photographing optical system is a single focal length optical system, the position of the open side stopper portion of the drive lever for opening and closing the light shielding blade may be always a fixed position, or in the open state. The opening area is also set to be always constant.

Therefore, the position of the opening-side stopper portion of the drive lever for opening and closing the light-shielding blade is completely retracted to the outside of the opening portion where the light-shielding blade is in the open state, and has a slight overstroke amount to the open side. Since it can be set to the position, the opening area in the open state should always be accurately determined even if the position of the open-side stopper, the position of the drive lever, the light-shielding blade, and the member shape error are taken into consideration. Will be possible.

Further, a so-called bounce phenomenon occurs when the drive lever for opening and closing the light shielding blade moves to the open state and the light shielding blade collides with the open side stopper portion which defines the position in the open state. Sometimes,
In this case, the amount of rotation of the light shielding blade in the opposite direction (closed side) due to the opening / closing drive lever of the light shielding blade bouncing should be considered in consideration of the overstroke amount and the like. Therefore, the accuracy of the opening area is not adversely affected.

In this way, if the opening side stopper position of the drive lever for opening / closing the light shielding blade is determined in consideration of the amount of overstroke of the light shielding blade on the opening side, the opening area in the open state of the opening is accurately determined. It is known that it is possible to do so and it becomes convenient in terms of optical performance.

On the other hand, by opening and closing the plurality of light-shielding blades, when the light-shielding blades are in the closed state, the opening is shielded, and when the light-shielding blades are in the opened state, the opening is opened. In a shutter mechanism that exposes the film surface, the light-shielding blades are inadvertently opened so that the photographer (camera user) intends to handle the unexposed film. On the contrary, it is necessary to prevent an accident such as exposure, but a proposal for preventing such an accident is made, for example, in Japanese Utility Model Laid-Open No. 2-55224.

The shutter mechanism disclosed in Japanese Utility Model Laid-Open No. 2-55224 is a lens shutter mechanism that moves in the optical axis direction integrally with a lens group for focus adjustment and the like, and moves outside the effective focus adjustment range. At this time, a projecting portion that engages the opening / closing member of the lens shutter mechanism at the closed position is provided on the fixing member of the camera body to prevent the shutter from being opened accidentally. .

[0019]

[Problems to be Solved by the Invention]
According to the means disclosed in Japanese Laid-Open Patent Publication No. 37400, Japanese Patent Laid-Open No. 64-526, etc., the number of light-shielding blades increases, so that the overlapping portions of the light-shielding blades cannot be shielded sufficiently, and there is a possibility of light leakage. There is a problem that it becomes large.

Further, the zoom interlocking aperture variable light shielding device, etc., wherein the opening side stopper position of the drive lever for opening and closing the light shielding blade is displaced in association with the zooming operation of the zoom lens of the photographing optical system. In the case of the long focal length side, the aperture area in the open state is fixed as in the case where the shutter mechanism does not have the variable aperture diameter function, that is, the photographing optical system is an optical system with a single focal length. It is possible to accurately determine the aperture member, but when it is on the short focus side, the opening portion in the open state is formed by the inner edge portion of the light shielding blade. The bounce phenomenon may occur when the lever collides with the opening side stopper portion, which adversely affects the accuracy of the opening area and the exposure accuracy. To become.

Further, when a strobe or the like is used at low brightness or the like, the strobe light emitting operation needs to be performed only when the light-shielding blade is open. In such a case, when a bouncing phenomenon occurs in the opening / closing drive lever of the light-shielding blade, the opening area in the open state is not stable, so that the timing of strobe light emission may be restricted.

As described above, a problem with the zoom interlocking variable aperture opening shading device is that the shading device having a plurality of shading blades of three or more displaces the opening in conjunction with the zooming operation. The same happens when trying to include a function to do so.

On the other hand, according to the means disclosed in Japanese Utility Model Laid-Open No. 2-55224, the shutter mechanism needs to be integrally formed with the focus adjusting lens or the like which constitutes the photographing optical system. There is a problem that the adjustment lens becomes large and heavy, and when it is applied to a zoom lens that has a function of changing the magnification of photographing, the occupying space is increased by increasing the size of each component. However, there is a problem that the shutter mechanism itself becomes large in size.

In order to solve the above-mentioned conventional problems, an object of the present invention is to displace the opening in a light-shielding device having four light-shielding blades by interlocking with the zooming function of the photographing optical system. A light-shielding device capable of ensuring good aperture accuracy in an open state without deteriorating the optical performance of an applicable photographing optical system and contributing to downsizing of the applicable photographing optical system. To provide.

Another object of the present invention is to provide a light-shielding device capable of reliably preventing an exposure accident or the like on a film caused by a careless opening operation of the light-shielding device.

[0026]

A light-shielding device according to the present invention is opened and closed by being rotated about a predetermined axis, and when it is in a closed state, a photographing light beam passing through a photographing optical system,
At least the light flux near the optical axis is shielded, and when it is in the open state, it is retracted from the passage of the photographing light flux, and a plurality of inner blades are opened and closed by being rotated around a predetermined axis,
When in the closed state, mainly the light flux of the peripheral portion of the photographing light flux passing through the photographing optical system is shielded, and when in the open state, it is retracted from the passage of the photographing light flux, and A plurality of outer blades that substantially overlap with each other, and a position defining unit that defines the positions of the plurality of outer blades in the open state and that changes the positions in association with the zooming operation of the photographing optical system. It is characterized by doing.

Further, when it is opened and closed by being rotated about a predetermined axis and is in the closed state, at least the light flux near the optical axis of the photographing light flux passing through the photographing optical system is shielded and is in the open state. In this case, the plurality of inner blades are retracted from the passage of the photographing light flux, and the blades are opened and closed by being rotated around a predetermined axis. , Which mainly shields the light flux in the peripheral portion and is retracted from the passage of the photographing light flux when in the open state, and has a plurality of outer blades that substantially overlap with each of the plurality of inner blades. The moving amount and moving speed of each of the plurality of inner blades and the plurality of outer blades at the time of opening and closing are set so that the inner blades of the plurality of sheets are larger than the inner blades of the plurality of inner blades during the opening operation. Moves past the outer blades The outer periphery of the imaging light beam in the open state is being determined by the inner edge of the plurality of outer blades.

Then, it is opened and closed by being rotated about a predetermined axis, and when in the closed state, at least the light flux near the optical axis is shielded from among the light fluxes passing through the photographic optical system,
When it is in the open state, it is retracted from the passage of the photographing light flux, and it is opened and closed by rotating it around a plurality of inner blades and a predetermined axis, and when it is in the closed state, it passes through the photographing optical system. Of the photographing light flux, mainly shielding the peripheral light flux, and when in the open state, retracted from the passage of the photographing light flux, and a plurality of outer blades, which substantially overlap with each of the plurality of inner blades, An inner blade cam that is provided on each of the plurality of inner blades and is constantly cam-coupled to the blade driving lever to transmit the driving force of the blade driving lever to the plurality of inner blades, and the plurality of inner blades. An outer blade cam provided on each of the outer blades and cam-coupled to the blade drive lever only at the initial stage of the opening operation, and each of the plurality of outer blades are urged in the opening direction, and the initial opening operation is performed. After that, move the outer blades Characterized by comprising a means.

[0029]

The plurality of inner blades are opened and closed by being rotated around a predetermined axis, and when in the closed state, block at least a light flux near the optical axis among the light fluxes passing through the photographing optical system. When in the open state, the image pickup light beam is retracted from the passage. The plurality of outer blades are opened and closed by rotating around a predetermined axis, and when in the closed state, mainly the peripheral light flux of the photographing light flux passing through the photographing optical system is shielded and the open state is maintained. When it is, the image pickup light beam is retracted from the passage and substantially overlaps with each of the plurality of inner blades.
The position defining means defines the positions of the plurality of outer blades in the open state, and changes the positions in conjunction with the zooming operation of the photographing optical system.

Further, the plurality of inner blades whose movement amount and movement speed at the time of opening / closing at the time of the opening operation are set to be large, move over the plurality of outer blades, and the outer periphery of the photographing light flux in the open state is as described above. It is determined by the inner edges of the plurality of outer blades.

The inner blade cam provided on each of the plurality of inner blades is constantly cam-coupled to the blade driving lever to transmit the driving force of the blade driving lever to the plurality of inner blades. The outer blade cams provided on each of the plurality of outer blades are cam-engaged with the blade drive lever only at the initial stage of the opening operation to urge each of the plurality of outer blades in the opening direction. The means moves the plurality of outer blades after the initial opening operation.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a vertical sectional view of a lens barrel having a photographing optical system such as a camera to which the light shielding device of the first embodiment of the present invention is applied. It is assumed that a zoom lens having a variable magnification function is applied to the photographing optical system of the camera, and the upper half of FIG. 1 shows a state where the lens barrel is on the wide angle (wide) side. , The lower half shows the state on the telephoto side.

First, a schematic structure of the lens barrel to which the light shielding device of the first embodiment is applied will be described below. As shown in FIG. 1, a first lens group 1 and a second lens group 2 are arranged in a lens barrel having the above-mentioned photographing optical system. By moving each position in the optical axis direction with respect to the film surface (image forming surface of the subject image), the zooming operation is performed, and the focusing operation is performed independently of this zooming operation. Focus adjustment is performed by moving only the first group lens 1 which is an adjustment lens in the optical axis direction.

The first group lens 1 and the second group lens 2 are
The first lens holding frame 3 is held by the first lens holding frame 3 and the second lens holding frame 4, respectively. The first lens holding frame 3 is fixed between the light blocking device base portions 5 and 6 that hold the light blocking device 17. It is slidably arranged by the supported first shaft 12.

Further, the light shielding device base portion 5 is provided with a through hole into which the second shaft 13 integrally formed with the second lens holding frame 4 is fitted.

A cam frame 7, a zoom frame 8, a guide frame 9, a fixed frame 10 and a rotary frame 11 which constitute this lens barrel.
Etc., the groove portions and the cam grooves, etc. provided on the inner peripheral surface or the outer peripheral surface thereof, and the corresponding pins etc. of these grooves etc. engage with each other to form the lens barrel. , The zooming operation is performed in association with each other (details of the operation will be described later).

On the other hand, the light-shielding device 17 includes an opening 16 into which a photographing light beam passing through the photographing optical system is incident, a plurality of light-shielding blades that shield or open the opening 16 to limit the amount of light, and the light-shielding blades. It is composed of a cover portion 14 to be held and an open aperture variable ring 15 which is a position defining means for defining the position of the light shielding blade, and between the first group lens 1 and the second group lens 2, It is disposed so as to be supported by the light shielding device base portion 5.

A zooming operation performed by the photographing optical system of the lens barrel configured as described above,
The outline of the focus adjustment operation will be briefly described below. First, zooming
When the operation is performed, the rotational drive force is transmitted to the rotary frame 11 rotatably arranged in the camera body by a zoom drive means (not shown) or the like provided in the camera body. By doing so, the rotary frame 11 is rotated.

A groove (not shown) is provided on the inner peripheral surface side of the rotating frame 11 in parallel with the optical axis, and the cam frame 7 is engaged by the groove and the cam frame pin 7a. Rotate in conjunction with.

The cam frame pin 7b of the cam frame 7 is
Since it engages with the cam groove (not shown) provided on the inner peripheral surface side of the fixed frame 10 fixed to the camera body,
The cam frame 7 is moved in the optical axis direction in association with the rotation of the cam frame 7.

The first lens holding frame 3 for holding the first group lens 1 is, as described above, the first shaft 12 supported between the light shielding device base portions 5 and 6 fixed to the zoom frame 8. The zoom frame 8 is slidably mounted on the zoom frame 8.
Are guided by the guide frame 9 interlocking with the movement of the fixed frame 10 in the optical axis direction so as to move straight in the optical axis direction.

The zoom frame pin 8a provided so as to project on the inner peripheral side of the zoom frame 8 is engaged with the cam groove provided on the outer peripheral surface of the cam frame 7, so that the zoom frame is provided. 8 is interlocked with the rotation of the cam frame 7 and is moved relative to the cam frame 7 in the optical axis direction.

On the other hand, a second lens holding the second lens group 2 is used.
The second lens holding frame pin 4a provided on the outer peripheral surface of the lens holding frame 4 is engaged with the cam groove provided on the inner peripheral surface side of the end portion of the cam frame 7, and the cam frame 7 The second lens holding frame 4 is rotated in association with the rotation of the
Therefore, the relative position is moved in the optical axis direction.

A second lens holding the second lens group 2 is used.
As described above, one end portion of the second shaft 13 is planted in the lens holding frame 4, and the second shaft 13 is
The other end of is fitted into the through holes formed in the light-shielding device bases 5 and 6. As a result, it is guided so as to go straight in the optical axis direction.

In this manner, the inner peripheral surface cam of the fixed frame 10 and the cam frame 7 are interlocked with the rotational movement of the rotary frame 11.
According to the shapes of the outer peripheral surface cam and the inner peripheral surface cam, the first group lens 1 and the second group lens 2 are moved in the optical axis direction, and a zooming operation is performed by the photographing optical system. .

Next, when the focusing operation by the photographing optical system of the lens barrel is performed,
As described above, only the first group lens 1 which is the focus adjusting lens is moved. That is, as described above, the shading device base portions 5 and 6 are fixed to each other to hold the shading device 17, and the space between the shading device base portions 5 and 6 is the above. The first shaft 12 is supported in parallel with the optical axis of the lens barrel. The first lens holding frame 3 is slidably arranged on the first shaft 12 in the optical axis direction.

The first lens holding frame 3 is supported by the shading device bases 5 and 6 and driven by a driving means (not shown) or the like, so that the above-mentioned zooming is performed.
Independently of the operation, the focus adjustment operation is performed by moving only the first group lens 1 in the optical axis direction of the lens barrel.

On the other hand, the first lens in the lens barrel
As described above, the shading device 17 of the embodiment is arranged on the rear side of the shading device base portion 5 between the first group lens 1 and the second group lens 2.

The shading device 17 is driven by a shading device driving means (not shown) fixed to the shading device base portions 5 and 6 to open the opening 16 by a plurality of shading blades. The opening and closing operation of is performed.

That is, a plurality of shading blades (details will be described later) arranged in the shading device are rotatably supported by a base portion 5a provided on the rear surface side of the shading device base portion 5. At the same time, it is sandwiched by the cover portion 14 and the position in the optical axis direction is defined.

The light shielding device 17 has an opening 16
Is provided, and is configured so that the opening area of the plurality of light-shielding blades when fully opened can be ensured with high accuracy.

An open opening variable ring 15 which is a position defining means for defining the position of the light shielding blade is rotatably supported on the cover portion 14. The open opening variable ring 15 is It is rotationally driven by a drive pin 4b provided on the second lens holding frame 4. As a result, it is possible to change the opening area of the light-shielding blade when it is fully opened, in conjunction with the zooming operation of the lens barrel.

FIGS. 2 and 3 are views for explaining the detailed construction of the shading device 17 of the first embodiment and its operation. FIG. 2 shows a plurality of openings 16 of the shading device 17. 3 is a diagram showing a closed state in which the light shielding blades are closed, and FIG. 3 is a diagram showing an open state in which the plurality of light shielding blades of the light shielding device 17 are retracted to the outside of the opening 16. Further, FIG. 4 is a diagram showing a schematic configuration of the light shielding device 17 of the first embodiment, and is an enlarged longitudinal sectional view of an essential part showing the vicinity of the light shielding device 17 in FIG. 1 described above in an enlarged manner.

As will be described later, the light-shielding device of the first embodiment has four light-shielding blades, that is, a pair of inner blades and a pair of outer blades, which move in opposite directions. By doing so, the opening 16 is opened and closed. However, in FIGS. 2 and 3, in order to avoid complication of the drawings, the pair of inner blades and the pair of outer blades are connected to each other. In FIG. 3, only one side is shown, and the other side is arranged at substantially symmetrical positions, and the illustration is omitted.

As shown in FIGS. 2 to 4, the shading device 17 of the first embodiment is opened and closed by moving in opposite directions, and when in the closed state, the photographic light flux passing through the photographic optical system. A pair of inner blades 17b and 17c that shields a light beam in the vicinity of the optical axis and is retracted from the passage of the photographing light beam in the open state (indicated by a solid line in FIGS. 2 and 3). ) Is opened and closed by being moved in the opposite directions, and when in the closed state, mainly the light flux in the peripheral part of the shooting light flux passing through the shooting optical system is blocked, and in the open state, the shooting light flux A pair of outer blades 17a that are retracted from the passage of the outer blade 17a and substantially overlap the pair of inner blades 17b,
17d (indicated by a broken line in FIGS. 2 and 3), and the pair of inner blades 17b and 17b.
c and the arrangement of the pair of outer blades 17a and 17d in the optical axis direction are, as shown in FIG. 4, in the optical axis direction, that is, from the base portion 5a side of the light shielding device base portion 5 to the film surface (subject image formation). The outer blade 17a, the inner blade 17b, the inner blade 17c, and the outer blade 17d are arranged in this order toward the surface side.

The four light-shielding blades, that is, the pair of inner blades and the pair of outer blades 17a to 17d, are attached to the base portion 5a of the light-shielding device base portion 5 at their respective rotation centers 18a.
The shafts are rotatably supported at ~ 18d.

Further, the four light shielding blades are provided with cam grooves near the rotation centers 18a to 18d, respectively. That is, in FIGS. 2 and 3, the cam groove 13b, which is the inner blade cam, of the inner blade 17b is the same as the outer blade 17a.
In FIG. 2, the cam grooves 13a which are the outer blade cams are formed respectively, and the inner blade 17c and the outer blade 17d which are other light-shielding blades not shown in FIGS. 2 and 3 respectively have the cam grooves 13c, 13d is provided.

The cam grooves 13a to 13d are provided on the drive pin 2 which is planted at one end of the blade drive lever 19.
0 coaxially engaged. As a result, drive means (not shown) for driving the blade drive lever 19
By driving the blade drive lever 19 around its rotation shaft 19a, the four light-shielding blades are simultaneously rotated about the respective rotation centers 18a to 18d, and the four light-shielding blades are rotated. Open and close the opening 16.

At this time, the pair of inner blades 17b, 17
c and the pair of outer blades 17a and 17d, the inner blade 17b and the outer blade 17a shown in FIGS. 2 and 3 are centered around the rotation centers 18b and 18a, and are rotated counterclockwise in the closing operation. To open the opening 16 by opening the opening 16 by rotating each of them to shield the opening 16 and rotating in the clockwise direction to retract to the outside of the opening 16 so as to be overlapped. 2, the inner blade 17c and the outer blade 17d, which are not shown in FIG. 3, are rotated clockwise about the rotation centers 18c and 18d in the closing operation to shield the opening 16 and open operation. At this time, the openings 16 are opened by rotating them counterclockwise and retracting to the outside of the openings 16 and overlapping them.

When the opening 16 is shielded by the four light-shielding blades and the opening area is large, the diaphragm opening is determined by the inner edges of the pair of outer blades 17a and 17d. Becomes

On the other hand, when the opening 16 is shielded by the four light-shielding blades and the opening area is made small (when the aperture is small), the pair of inner blades 17b, 1b is used.
The diaphragm opening is formed by the inner edge of 7c. At this time, the smaller the opening area, the more likely it is to be affected by light leakage in the gap between the light shielding blades. Further, in the light-shielding device, generally, there is a tendency that the above-mentioned light leakage is likely to increase by increasing the number of light-shielding blades.

Therefore, in the light shielding device 17 of the first embodiment, as described above, the opening 16 at the time of the small aperture is set.
Is formed by the inner edge portions of the pair of inner blades 17b, 17c, the pair of inner blades 17b, 1c
7c are arranged so as to be adjacent to each other so as to reduce the light leakage that occurs when the small aperture is made.

Further, the tip portions of the pair of inner blades 17b and 17c are shaped so as to ensure a state of always overlapping even in the open state, and the order of overlapping the four light shielding blades is always ensured. It is supposed to be done.

FIG. 5 is a schematic view of the light-shielding device base portion 5 supporting the light-shielding device 17 as viewed from the blade drive lever 19 side. Note that, also in FIG. 5, in order to avoid complication of the drawing, the above-mentioned four light shielding blades 17a to 17d are provided.
Only the arrangement of the blade drive lever 19 for driving the blades is shown, and other members are omitted in the drawing.

As shown in FIGS. 4 and 5, the blade drive lever 19 is a surface of the base portion 5a of the light shielding device base portion 5 opposite to the side on which the light shielding blades 17a to 17d are arranged. In the above, the drive pin 20 is rotatably supported about the rotation shaft 19a, and the drive pin 20 penetrates the hole 5b provided in the base 5a of the light-shielding device base 5 and, as described above, Four light-shielding blades 17a-1
It is constituted by engaging with the cam grooves 13a to 13d of 7d.

When the blade drive lever 19 is driven by a drive means (not shown) or the like and the drive pin 20 is rotated accordingly, it is provided on the base portion 5a of the light-shielding device base portion 5. The drive pin 20 is brought into contact with the upper end portion (open side stopper portion O) and the lower end portion (closed side stopper portion C) of the hole portion 5b thus formed, whereby positioning is performed. The positions of the open state and the closed state when the opening 16 is opened and closed, which is determined by the light shielding blades 17a to 17d engaged with the drive pin 20, are defined.

Further, as shown in FIG. 4, an open opening variable ring 15 as a position defining means is rotatably supported by a cover portion 14 supported on one end side of the light shielding device base portion 5. This open opening variable ring 1
As shown in FIG. 1 described above, 5 is rotationally driven by a drive pin 4b provided on the second lens holding frame 4.

As a result, the open opening variable ring 1 is provided.
The zoom lens 5 moves integrally with the first lens holding frame 3 (first lens group 1) when a zooming operation is performed.

Here, the first and second lens groups 1 and 2 are
As described above, the position in the optical axis direction is displaced as the magnification is changed, but the relative distance between the first and second group lenses 1 and 2 is also changed. Therefore, the distance between the first and second lens groups 1 and 2 is uniquely determined in accordance with the zooming position during the zooming operation.

That is, in the zooming operation, the open aperture variable ring 15 that moves integrally with the first lens group 1 and the drive pin 4b of the second lens holding frame 4 in the optical axis direction. The relative positional relationship is uniquely determined corresponding to the zooming position.

Further, at the portion where the drive pin 4b of the second lens holding frame 4 and the opening opening variable ring 15 are engaged, the engaging portion is formed in a tapered shape, and the opening opening is formed. The position of the opening variable ring 15 in the rotational direction can be changed according to the relative position of the part variable ring 15 and the drive pin 4b of the second lens holding frame 4 in the optical axis direction. Has become. Therefore,
The position of the open opening variable ring 15 in the rotation direction is also uniquely determined corresponding to the zooming position.

Further, FIGS. 6 and 7 show the open aperture variable ring 15 when the magnification changing operation is performed by the above-mentioned photographing optical system.
FIG. 6 is a diagram showing a positional relationship between the blade driving lever 19 and the blade driving lever 19, and FIG. 6 is a diagram showing a state of the open aperture variable ring 15 when the photographing optical system is on the telephoto side, and FIG. It is a figure which shows the state of the open aperture variable ring 15 when a photography optical system exists in the wide-angle (wide) side.

According to FIGS. 6 and 7, the light shielding device 1 is described.
Variable opening ring 1 when variable magnification operation of 7 is performed
The positional relationship between the blade 5 and the blade drive lever 19 will be described below.

First, as shown in FIG. 6, when the photographing optical system is on the telephoto side, the open aperture variable cam 15a provided on the open aperture variable ring 15 and the drive pin 20 are connected. The relative positional relationship is that the opening opening variable cam 15a is located outside the full opening stopper position O of the light shielding device base portion 5. Therefore, the drive pin 20
Is positioned by the hole 5b of the light-shielding device base 5 without being affected by the open-opening variable ring 15.

On the other hand, when the magnification changing operation of the photographing optical system is performed from the state shown in FIG. 6 to the wide angle side, the open aperture variable ring 15 is rotated counterclockwise to the state shown in FIG. , The photographing optical system moves to the wide-angle side. In this state, the relative positional relationship between the opening opening variable cam 15a of the opening opening variable ring 15 and the drive pin 20 is such that the opening opening variable cam 15a is closer to the full opening stopper position O of the light shielding device base portion 5. It is located on the inner diameter side. Therefore,
The drive pin 20 comes into contact with the open opening variable cam 15a before coming into contact with the full-open stopper position O, whereby the position thereof is defined, and the position is closer to the closing side than the above-mentioned full-open stopper position O. Will stop at.

Therefore, the four light-shielding blades opened and closed by the blade drive lever 19 are not completely retracted from the opening 16 and the opening operation is stopped with the peripheral portion of the opening 16 being shielded. Therefore, the opening area is set to be smaller than the opening area 16 at the time of telephoto described with reference to FIG.

As described above, in FIGS. 6 and 7, the positional relationship between both ends of the telephoto side and the wide-angle side at the time of zooming is described. However, even at an intermediate zoom position, By changing the shape of the open opening variable cam 15a, the opening 1 at the intermediate position can be changed.
It is possible to arbitrarily set the size of the aperture opening in 6.

In this way, the position defining means defines the position of the pair of outer blades 17a in the open state, and changes the position in association with the zooming operation of the photographing optical system. An open aperture variable ring 15 is provided, which is interlocked with the zooming operation of the photographing optical system to arbitrarily change the area of the aperture opening when the four light shielding blades are fully opened. It has become a structure.

By the way, as described above, when the pair of inner blades 17b and 17c is in the closed state, of the photographing light flux passing through the photographing optical system, the luminous flux in the vicinity of the optical axis, that is, the center of the opening 16. It is designed to shield the vicinity of the part,
When it is in the open state, it is retracted from the outside of the opening 16, that is, from the passage of the photographing light flux.

Then, the pair of inner blades 17b, 17c
However, when moving from the closed state to the open state at the initial stage, that is, when the opening area of the opening 16 is small (at the time of a small aperture), the pair of inner blades 17b, 17 is formed.
A diaphragm aperture is formed by the inner edge of c.

Further, the pair of outer blades 17a, 17d
Of the photographing light flux passing through the photographing optical system when in the closed state, mainly shields the peripheral light flux, that is, the peripheral portion of the opening 16, and when in the open state, the pair of inner blades. 17
b and 17c so as to be substantially overlapped with each other, so as to be retracted from the outside of the opening 16, that is, from the passage of the photographing light flux.

Therefore, the pair of inner blades 17b, 17c
Moves by rotating between a fully closed state and a fully opened state, that is, a state of being retracted to the outside of the opening 16, that is, a movement at the time of opening and closing. In, the moving amount and moving speed are larger than those of the pair of outer blades 17a and 17d.

Further, the pair of outer blades 17a, 17d
Of the photographing light flux passing through the photographing optical system when in the closed state, mainly shields the peripheral light flux, that is, the peripheral portion of the opening 16, and when in the open state, the pair of inner blades. 17
b and 17c so as to be substantially overlapped with each other, so as to be retracted from the outside of the opening 16, that is, from the passage of the photographing light flux.

In the closed state, the pair of inner blades 1
Gap 21 between the outer edge of 7b and 17c and the opening 16
(See FIG. 2) is shielded by the pair of outer blades 17a and 17d.

Therefore, the position of the pair of outer blades 17a, 17d in the closed state is set to the position of the pair of inner blades 17b, 1b.
7c is set to a position closer to the retracted position when fully opened, and the moving amount when the pair of outer blades 17a and 17d is moved from the closed state to the open state is the same as the pair of inner blades 17c.
It is set to be smaller than b and 17c.
The moving speed of the pair of outer blades 17a, 17d when driven by the blade driving lever 19 is also lower than that of the pair of inner blades 17b, 17c.

8 and 9 are views conceptually showing the operation of the blade drive lever 19 and the operation of the pair of inner blades 17b and 17c and the pair of outer blades 17a and 17d. 9 shows the change of the aperture opening formed in the opening 16 from the fully closed state to the fully open state. FIG. 9 shows the state when the blade drive lever 19 is positioned by the open side stopper portion O. It is shown.

8 and 9, the horizontal axis represents the rotational position (rotation angle) of the blade drive lever 19, and the vertical axis represents the rotational position.
A pair of inner blades 17b and 17c and a pair of outer blades 17
The change in the area of the aperture opening formed by the inner edge portions of a and 17d is shown.

Further, in FIGS. 8 and 9, the opening 1 formed by the inner edges of the pair of inner blades 17b and 17c.
The area change (A) of No. 6 is shown by a solid line, and the area change (B) of the opening formed by the inner edges of the pair of outer blades 17a and 17d is shown by a broken line.

The relationship between the rotation angle of the blade driving lever 19 and the rotation angles of the pair of inner blades 17b and 17c and the pair of outer blades 17a and 17d will be described below with reference to FIGS. As shown in FIG. 8, in accordance with the operation of the blade drive lever 19, the aperture opening is divided into the pair of inner blades 17b and 17c and the pair of outer blades 17a and 17d.
From the state in which it is completely shielded by (the fully closed stopper position) to the state in which the diaphragm opening is mainly formed by the inner edge portions of the pair of inner blades 17b and 17c (between the fully opened stopper position and θ1). , Mainly a pair of outer blades 1
A state in which a diaphragm opening is formed by the inner edge portions of 7a and 17d (between θ2 and the fully closed stopper position), and a pair of inner blades 17b and 17c and a pair of outer blades 1
Both 7a and 17d change to a state where they are retracted outside the opening 16 (full-open stopper position).

At this time, the relative operation of the pair of inner blades 17b and 17c and the pair of outer blades 17a and 17d is determined by the locus of the drive pin 20, the positions of the rotation centers 18a to 18d of the light shielding blades, and the light shielding blades 17a. -17d cam grooves 13a-13
Although it will be comprehensively determined by the shape of d,
In the light shielding device 17 of the first embodiment, as described above, the pair of inner blades 17b and 17c are arranged to move the pair of outer blades 17a and 17d in the process of moving the aperture opening from the closed state to the open state. It is configured to move overtaking.

When the opening 16 is fully opened, a pair of inner blades 17b and 17c and a pair of outer blades 17a and
Both 17d are retracted to the outside of the opening 16, but in this state, the inner and outer edges of the pair of inner blades 17b and 17c and the pair of outer blades 17a and 17d are housed so as to substantially overlap each other. However, this is advantageous in reducing the size of the light shielding device.

Therefore, the inner edge portions of the pair of inner blades 17b, 17c, which have overtaken the inner edge portions of the pair of outer blades 17a, 17d during the movement to the open state, have the pair of outer blades 17a in the fully opened state. , 17d so as to substantially overlap with the inner edge portions thereof.

This is, for example, a pair of inner blades 17b, 1
The cam grooves 13b, 13c of 7c are shaped so as to be bent at the portion corresponding to the fully open state of the opening 16, and the pair of inner blades 17 is operated with respect to the operation of the blade drive lever 19.
This can be achieved by setting the moving speeds of b and 17c so that they become slower as they approach the fully open state.

Next, in the case of displacing the opening area according to the zooming operation, as described above, the open opening variable ring 15 that changes in the rotation direction with the zooming operation. The position of the open side stopper of the blade drive lever 19 is changed according to the above. The change range of the open side stopper is set between θ1 and θ2 in FIG. 8, and the opening area of the opening 16 is S1. It is set to be displaced in the range of to S2.

Here, θ1 is a pair of inner blades 17
The inner edge portions of b and 17c are the rotational position (rotation angle) of the blade drive lever 19 at the time of overtaking the inner edge portions of the pair of outer blades 17a and 17d, and the opening area at this time is S1.

Further, the above-mentioned θ2 is a pair of outer blades 17a,
It is the rotational position (rotation angle) of the blade drive lever 19 at the time when the inner edge of 17d is retracted to the outside of the opening 16, and the opening area at this time is S2. The opening area S2
Is equal to the opening area of the opening 16 in the fully opened state.

FIG. 9 shows the position when the blade drive lever 19 is defined by the open opening variable cam 15a by θ.
3 is shown as an example, and the aperture area of the aperture opening at this time is a state formed by the inner edge portions of the pair of outer blades 17a and 17d, and the aperture areas S1 and S described above are shown.
It will be determined by S3 within the range of 2.

At this time, as shown in FIG. 9, there is a possibility that the blade drive lever 19 may bounce due to the impact when it collides with the open opening variable cam 15a. In this case, a pair of inner blades 17b is formed. , 17c and the pair of outer blades 17a, 17d both change their positions.

Here, as described above, with respect to the rotation amount of the blade drive lever 19, the pair of outer blades 17a and 17a
Since the amount of movement of d is set to be smaller than the amount of movement of the pair of inner blades 17b and 17c, it may be bound by the blade drive lever 19 when it collides with the open opening variable cam 15a. The influence of the resulting change in the opening area on the exposure amount and the like can be suppressed.

As described above, according to the first embodiment, the pair of light-shielding blades for shielding and opening the opening 16 are the pair of inner blades 17b and 17c and the pair of outer blades 17.
By configuring the four blades a and 17d, the size of each light shielding blade can be reduced, and when the opening 16 is open, the pair of inner blades 17 is formed.
Since the b and 17c and the pair of outer blades 17a and 17d are overlapped with each other and retracted to the outside of the opening 16, the retracting space of the light shielding blade can be reduced. Thereby, it is possible to contribute to downsizing of the light shielding device and also to miniaturization of the entire lens barrel to which the light shielding device is applied.

Further, since the pair of inner blades 17b and 17c are arranged adjacent to each other, it is possible to reduce light leakage when the aperture is small. Therefore, it is possible to improve the accuracy of the light amount control by the above-mentioned four light-shielding blades, and the problem of the light-shielding device having a plurality of light-shielding blades, that is, the problem of increasing light leakage due to an increase in the gap between the light-shielding blades is minimized You can keep it to the limit.

Then, the pair of inner blades 17b, 17c
The pair of inner blades 17b, 17c in the open state are arranged so that the tip portions of the inner blades 17b, 17c are always overlapped with each other.
Since the pair of outer blades 17a and 17d are arranged on both sides of 17c, the order of overlapping of the four light shielding blades in the optical axis direction is maintained even when the four light shielding blades are opened and closed. Therefore, a good opening / closing operation can always be ensured.

In the first embodiment, a pair of inner blades 17b and 17c and a pair of outer blades 17a and 17d are provided as the light-shielding blades, and the moving speed and the moving amount of the pair of inner blades 17b and 17c are paired. Outer blades 17a, 17d
It is possible to change the positions of the opening side stoppers of the pair of outer blades 17a and 17d in association with the zooming operation, and thus it is possible to obtain a zoom variable aperture device with high aperture accuracy.

FIG. 10 and FIG. 11 are views for explaining the structure and operation of the light shielding device of the second embodiment of the present invention. FIG. 10 shows that the opening of this light shielding device has a plurality of light shielding blades. In the closed state where it is shielded, and FIG.
It is a figure which respectively shows the open state in which several light-shielding blades of this light-shielding device were retracted outside the opening. In addition, FIG.
[FIG. 6] is an enlarged view of a main part showing an enlarged view of a cam groove 13Aa which is an outer blade cam formed in the outer blade 17Aa.

The shading device of the second embodiment is basically of the same construction as that of the first embodiment described above, but in the second embodiment, the pair of outer parts is used. An urging means for urging each of the blades in the opening direction and moving the pair of outer blades after the initial opening operation,
Furthermore, the points that are equipped are different. Therefore, the same members as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

In FIGS. 10 and 11, the pair of inner blades and the pair of outer blades are provided on one side, respectively, in order to avoid complication of the drawing, as in the first embodiment. Only the other side is shown, and the other side is arranged at substantially symmetrical positions, and the illustration thereof is omitted. Also,
In FIG. 12, of the pair of outer blades 17Aa and 17Ad, only one outer blade 17Aa is shown, but the other outer blade 17Ad has a substantially symmetrical shape, and therefore the illustration thereof is omitted. Omitted.

As shown in FIGS. 10 and 11, in the light shielding device of the second embodiment, the pair of inner blades 17Ab, 17Ac and the pair of outer blades 1 are provided in the same manner as in the first embodiment.
7Aa and 17Ad are arranged.

The pair of inner blades 17Ab, 17Ac (indicated by solid lines in FIGS. 10 and 11).
Are opened and closed by moving in opposite directions, and when in the closed state, block the light flux near the optical axis of the shooting light flux that passes through the shooting optical system, and when in the open state, pass the shooting light flux. It is configured to be retracted from the path, and also has a pair of outer blades 17Aa and 17Ad (see FIGS. 10 and 11).
Is indicated by a broken line. ) Are opened and closed by being moved in opposite directions, and when in the closed state, mainly the light flux in the peripheral part of the shooting light flux passing through the shooting optical system is blocked, and in the open state, the shooting light flux Of the inner blade 17Ab and is substantially overlapped with the pair of inner blades 17Ab.

Then, the pair of outer blades 17Aa, 17
A biasing spring 22 as a biasing means is provided in each Ad, and the pair of outer blades 17Aa and 17Ad are
Each is always biased in the opening direction.

Further, as shown in FIG. 12, the cam groove 13A of the pair of outer blades 17Aa, 17Ad engaging with the drive pin 20 of the blade driving lever 19 for opening and closing the light shielding blade.
a, 13Ad (17Ad, 13Ad are not shown) are provided with respect to the cam grooves (indicated by dotted lines in FIG. 12; reference numeral 13) of the light shielding blade in the conventional light shielding device.
It has a shape having a first relief portion 24 and a second relief portion 25.

Further, the pair of outer blades 17Aa, 17
A projecting portion 23 is provided on the outer edge of Ad, and the projecting portion 23 and the open opening variable cam 15a (not shown) of the open opening variable ring 15 (not shown) come into contact with each other. Similar to the above-described first embodiment, the opening side stopper positions of the pair of outer blades 17Aa, 17Ad are displaced in association with the zooming operation of the photographing optical system, and thereby the opening area of the light shielding blade when fully opened. It can be changed.

That is, the second relief portion 25 is provided with the drive pin 2 when the open side stopper position of the pair of outer blades 17Aa, 17Ad is set to the front side of the fully open state.
It is formed as a space where 0 is retracted.

The operation of the light shielding device of the second embodiment thus constructed will be described below. 13 and 1
4 is a view conceptually showing the operation of the pair of inner blades 17Ab, 17Ac and the pair of outer blades 17Aa, 17Ad with respect to the operation of the blade drive lever 19, and FIG. FIG. 14 shows the change from the closed state to the fully open state, and FIG. 14 shows the state when the position of the blade drive lever 19 is regulated by the open side stopper portion.

In FIGS. 13 and 14, as in FIGS. 8 and 9, the horizontal axis represents the rotational position (rotational angle) of the blade drive lever 19, and the vertical axis represents the pair of internal positions. Blade 17A
b, 17Ac and changes in the area of the diaphragm aperture formed by the inner edges of the pair of outer blades 17Aa, 17Ad.

Further, in FIGS. 13 and 14, the area change (A) of the aperture opening formed by the inner edge portions of the pair of inner blades 17Ab, 17Ac is shown by a solid line, and the inner edge portions of the pair of outer blades 17Aa, 17Ad are shown. The change in area (B) of the aperture opening formed by is indicated by broken lines.

First, when the light shielding blade is moved from the closed state to the open state, the drive pin 20 is cam-connected to the first escape portion 24 in the initial stage of the open state. Then, the pair of outer blades 17A
a and 17Ad are urged by the urging force of the urging spring 22.
Since the pair of outer blades 17Aa and 17Ad are always biased in the opening direction, the positions of the pair of outer blades 17Aa and 17Ad in the open state are the same as those in the first
It will be prescribed in the escape portion 24.

At this time, when the driving of the blade drive lever 19 in the opening direction is started, the pair of outer blades 17Aa, 1
7Ad moves prior to the operation of the blade drive lever 19 by the urging force of the urging spring 22, and is fully opened in this state.

In addition, the pair of inner blades 17Ab, 17A
Since c is constantly cam-coupled to the blade drive lever 19 in the cam grooves 13Ab and 13Ac, the drive force of the blade drive lever 19 is transmitted to drive c to the fully open state. Thereby, the opening 16
The aperture opening formed in is always a pair of inner blades 17Ab,
It will be mainly formed in the inner edge portion of 17Ac. (See FIG. 13) On the other hand, when the light shielding blade is moved from the open state to the closed state, the drive pin 20 and the cam grooves 13Aa, 13A of the pair of outer blades 17Aa, 17Ad.
By engaging with the cam surface 26 of d, the pair of outer blades 17Aa, 17Ad are rotated in the closing direction against the urging force of the urging spring 22 and transition to the closed state. Become.

Next, when the magnification changing operation is performed by the photographing optical system and the opening area of the opening is displaced in conjunction with this, the pair of outer blades 17 is accompanied by the magnification changing operation.
Although the open side stopper positions of Aa and 17Ad are displaced, in this case, the pair of outer blades 17A
a, 17Ad open side stopper position, the blade drive lever 1
The rotation angle θ3 of 9 and the aperture area of the diaphragm aperture at this time are S3 will be described below with reference to FIG.

As shown in FIG. 14, a pair of outer blades 17A
The opening area of the aperture opening formed by the inner edges of the pair of outer blades 17Aa, 17Ad at the time when the a, 17Ad is moved ahead of the pair of inner blades 17Ab, 17Ac and reaches the opening side stopper position is It is S3, but until reaching this point, the pair of inner blades 1
The aperture area of the aperture opening formed by the inner edge portions of 7Ab and 17Ac is smaller than the above S3. Therefore, the diaphragm aperture up to this point is the pair of inner blades 17A.
It is formed by the inner edge portion of b, 17Ac.

The pair of inner blades 17Ab, 17B
Ac is further driven in the opening direction by the blade drive lever 19, and the pair of inner blades 17Ab, 17Ac
However, at the time when it passes the pair of outer blades 17Aa, 17Ad (after the blade drive lever rotation angle θ3 in FIG. 14), the opening is in the fully open state, and at this time, the aperture opening is the pair of outer blades. 17Aa, 17Ad
Will be formed by the inner edge of the.

Therefore, as shown in FIG. 14, even if the pair of outer blades 17Aa, 17Ad collide with the open side stopper portion and the bounce phenomenon occurs, the pair of outer blades 17A can be formed.
Since there will be a slight time lag until the opening is formed by the inner edges of the a and 17Ad, the bound phenomenon of the pair of outer blades 17Aa and 17Ad is sufficiently attenuated and stabilized. Then, the pair of outer blades 17
It is possible to form the diaphragm aperture by the inner edge portions of Aa and 17Ad.

As described above, according to the second embodiment, the same effect as that of the first embodiment can be obtained, and the pair of outer blades 17Aa, 17Ad are always biased in the opening direction. By providing the biasing spring 22 as the biasing means, the opening area can be accurately adjusted without being affected by the bounce phenomenon that occurs when the pair of outer blades 17Aa and 17Ad collide with the opening side stopper portion. Can be secured.

FIG. 15 is a vertical sectional view of a lens barrel having a photographing optical system such as a camera to which the light shielding device of the third embodiment of the present invention is applied. Note that, in FIG. 15, only the upper half of the lens barrel is shown, and the lower half having a substantially symmetrical shape is omitted. In addition, the above lens barrel is used when the camera to which it is applied is not taking a picture (when not in use, when carrying, etc.)
In FIG. 15, the lens barrel is in the reset position (details will be described later).

FIG. 16 is a view showing the light-shielding blades and the like which constitute the light-shielding device of the third embodiment, and shows the closed state in which the opening is shielded by a plurality of light-shielding blades. In addition, in FIG. 16, the above-mentioned first,
As in the second embodiment, in order to avoid complication of the drawing, the pair of inner blades and the pair of outer blades are shown only on one side, and the other side is arranged in a substantially symmetrical position. The illustration is omitted as it is provided.

As shown in FIG. 15, a locking pin 3a for locking the light-shielding blade is arranged at the rear end side of the first lens holding frame 3 for holding the first lens group 1, and the light-shielding device base is provided. The base portion 5a of the portion 5 has an escape hole 5 penetrating the light shielding device base portion 5c at a position facing the locking pin 3a.
c is provided.

Further, as shown in FIG. 16, a recess 27 is provided at the outer edge of the outer blade 17Ba corresponding to the locking pin 3a, and the locking pin 3a serves as the light-shielding blade base. When the light shielding blade penetrates through the portion 5 and projects into the rotating plane of the light shielding blade, the light shielding blade is engaged with this.

When the light shielding blade is fully closed, the concave portion 17 and the locking pin 3a are engaged with each other.
Rotational movement of the outer blade 17Ba in the opening direction is restricted.

By restricting the opening operation of the outer blade 17Ba in this manner, the rotation of the blade drive lever (not shown) is also restricted, and at the same time the opening operation of the other light shielding blades is restricted. Therefore, the opening operation of all the light shielding blades is regulated.

By the way, as described in the first embodiment, the focus adjusting (focusing) operation causes the first lens holding frame 3 to move independently of the magnification changing (zooming) operation. It is performed by sliding along the first shaft 12 in the optical axes 5 and 6, but when the camera to which the lens barrel is applied is not photographing (when not in use, when carrying, etc.), As shown in FIG. 15, the first lens holding frame 3 includes the light blocking device base portion 5
Inside, the position is set to the rearmost position, that is, the reset position, and the state at this time is outside the movement range during focus adjustment.

On the other hand, when a photograph is taken, the first lens holding frame 3 is moved within the focus adjustment range by a predetermined amount based on the distance measurement information from the inside of the camera body, and then the light is shielded. When the device is opened / closed, a photography operation is performed. Then, after the photography operation is completed, the first lens holding frame 3 is returned to the reset position again.

As described above, when the first lens holding frame 3 is at the reset position, the locking pin 3a penetrates the light blocking device base portion 5 and projects into the rotation plane of the light blocking blade. It has become.

Therefore, in this state, the opening operation of the light shielding blade by the locking pin 3a is restricted.

That is, when a picture is taken, the first lens holding frame 3 is in the focus adjustment range, so that the locking pin 3a is retracted from the rotary plane of the light-shielding blade. On the other hand, the light-shielding blade opening / closing operation is performed, while the first lens holding frame 3 is out of the focus adjustment range during non-shooting.
By projecting a into the rotation plane of the light blocking blade, the opening operation of the light blocking blade is restricted.

As described above, according to the third embodiment, the same effect as that of the first and second embodiments can be obtained, and the non-photographing is performed regardless of the zooming position of the photographing optical system. At this time, the locking pin 3 of the first lens holding frame 3
Since the opening operation of the shading device is reliably regulated by a, the opening part is opened by the careless opening of the shading device due to, for example, an external force applied to the camera. It is possible to prevent such an accident that the film is opened and the film is exposed unintentionally.

In the embodiment described in detail above, the shutter mechanism constituted by the pair of inner blades and the pair of outer blades which are moved in opposite directions by the blade drive lever is provided.
The case where the light shielding device of the present invention is applied has been described.
For example, as shown in FIGS. 17 and 18, a shutter mechanism in which a plurality of blades are rotated in the same direction around their respective rotation axes by a light-shielding blade opening / closing drive ring member 31 to perform opening / closing operations. Can also be applied to. Note that FIG. 17 shows the closed state of the light shielding blade of the shutter mechanism, and FIG. 18 shows the opened state of the light shielding blade of the shutter mechanism.

The number of inner blades and the number of outer blades do not have to be two each, and the number of inner blades and outer blades can be appropriately selected according to the retreat space. In this case, the number of inner blades and the number of outer blades do not have to be the same. For example, the number of inner blades is two and the number of outer blades is three. It is also possible to make it smaller than the load and increase the driving speed of the inner blade.

[Supplementary Notes] (1) At least the light flux near the optical axis of the photographing light flux passing through the photographing optical system is shielded when it is opened and closed by being rotated about a predetermined axis and is closed. When it is in the open state, it is retracted from the passage of the photographing light flux, and it is opened and closed by rotating it around a plurality of inner blades and a predetermined axis, and when it is in the closed state, it passes through the photographing optical system. Of the photographing light flux, mainly shielding the peripheral light flux, and when in the open state, retracted from the passage of the photographing light flux, and a plurality of outer blades, which substantially overlap with each of the plurality of inner blades, A light shielding device, comprising: a position defining unit that defines a position of the plurality of outer blades in an open state, and that changes the position in association with a zooming operation of the photographing optical system.

(2) It is opened and closed by being rotated about a predetermined axis, and when it is in the closed state, at least the light flux in the vicinity of the optical axis of the photographing light flux passing through the photographing optical system is shielded,
When it is in the open state, it is retracted from the passage of the photographing light flux, and it is opened and closed by rotating it around a plurality of inner blades and a predetermined axis, and when it is in the closed state, it passes through the photographing optical system. Of the photographing light flux, mainly shielding the peripheral light flux, and when in the open state, retracted from the passage of the photographing light flux, and a plurality of outer blades, which substantially overlap with each of the plurality of inner blades, And the moving amount and the moving speed of each of the plurality of inner blades and the plurality of outer blades at the time of opening and closing are set such that the inner blades of the plurality of sheets are set to have a larger movement amount and moving speed. A light-shielding device in which a plurality of inner blades pass over the plurality of outer blades and the outer circumference of the photographing light flux in the open state is determined by the inner edge portions of the plurality of outer blades.

(3) It is opened and closed by being rotated about a predetermined axis, and when it is in the closed state, at least the light flux in the vicinity of the optical axis of the photographing light flux passing through the photographing optical system is shielded,
When it is in the open state, it is retracted from the passage of the photographing light flux, and it is opened and closed by rotating it around a plurality of inner blades and a predetermined axis, and when it is in the closed state, it passes through the photographing optical system. Of the photographing light flux, mainly shielding the peripheral light flux, and when in the open state, retracted from the passage of the photographing light flux, and a plurality of outer blades, which substantially overlap with each of the plurality of inner blades, An inner blade cam that is provided on each of the plurality of inner blades and is constantly cam-coupled to the blade driving lever to transmit the driving force of the blade driving lever to the plurality of inner blades, and the plurality of inner blades. An outer blade cam provided on each of the outer blades and cam-coupled to the blade drive lever only at the initial stage of the opening operation, and each of the plurality of outer blades are urged in the opening direction, and the initial opening operation is performed. After that, move the outer blades Shading device comprising a means.

(4) In the light-shielding device described in Supplementary Note 1 or Supplementary Note 3, the amount of movement of each of the plurality of inner blades and the plurality of outer blades at the time of opening and closing is greater for the plurality of inner blades. It is set.

(5) In the light-shielding device described in Supplementary Note 1 or Supplementary Note 3, the moving speed of each of the plurality of inner blades and the plurality of outer blades at the time of opening and closing is larger for the plurality of inner blades. It is set.

(6) In the light-shielding device described in Supplementary Note 1 or Supplementary Note 3, the plurality of inner blades move past the plurality of outer blades during the opening operation, and the outer periphery of the photographing light flux in the open state is the plurality of outer peripheral portions. Determined by the inner edges of the outer blades.

(7) In the light-shielding device described in Supplementary Note 1 or Supplementary Note 3, the amount of movement and the moving speed of each of the plurality of inner blades and the plurality of outer blades at the time of opening and closing are the same as those of the plurality of inner blades. One is set larger.

(8) In the light-shielding device described in Supplementary Note 1, Supplementary Note 2 or Supplementary Note 3, the moving amount and the moving speed of each of the plurality of inner blades and the plurality of outer blades at the time of opening and closing are the same as those of the plurality of sheets. The inner blade is set to be larger, and the plurality of inner blades move over the plurality of outer blades during the opening operation, and the outer periphery of the photographing light flux in the open state is the inner edge portion of the plurality of outer blades. Determined by

(9) In the light-shielding device described in Supplementary Note 1, Supplementary Note 2 or Supplementary Note 3, each of the plurality of inner blades is constantly cam-coupled to the blade drive lever, and the drive force of the blade drive lever is set to the above. It has an inner blade cam that is transmitted to a plurality of inner blades.

(10) In the light-shielding device described in Supplementary Note 1 or Supplementary Note 3, each of the plurality of outer blades has an outer blade cam that is cam-coupled to the blade drive lever only at the initial stage of the opening operation.

(11) In the light-shielding device described in appendix 10, the plurality of outer blades are biased in the opening direction.

(12) In the light-shielding device described in Supplementary Note 3 or Supplementary Note 11, the plurality of outer blades are closed by the blade drive lever against the biasing force of the biasing means.

(13) In the light-shielding device described in Supplementary Note 2 or Supplementary Note 3, the positions of the plurality of outer blades in the open state are further defined, and this position is adjusted in association with the zooming operation of the photographing optical system. It has a position defining means for changing.

(14) In the light-shielding device described in Supplementary Note 1, Supplementary Note 2 or Supplementary Note 3, the photographic optical system performs focusing operation by advancing and retracting in the optical axis direction independently of the magnification changing operation. When the focus adjusting optical system has a system and is in a non-photographing state, a part of the focus adjusting lens frame that holds the system is provided in at least one of the plurality of inner blades and the plurality of outer blades. Engage and regulate their opening motion.

(15) In the light-shielding device described in appendix 14, a part of the focus adjusting lens frame is formed by a protrusion.

(16) In the light shielding device described in appendix 14, the focus adjusting optical system is located at a position outside the range of movement during focus adjustment in the non-shooting state.

(17) It is opened and closed by being rotated around a predetermined axis, and when it is in the closed state, it blocks the photographing light flux passing through the photographing optical system, and when it is in the open state, it is on the passage path of the photographing light flux. Light shielding having a plurality of blades retracted from the blades and position defining means for defining the positions of the plurality of blades in the open state and changing the positions in association with the zooming operation of the photographing optical system. In the device, the photographing optical system is
It has a focus adjustment optical system that performs focusing operation by moving forward and backward in the optical axis direction independently of the zooming operation, and when this focus adjustment optical system is in a non-shooting state, a focus that holds it A light-shielding device in which a part of the adjusting lens frame is engaged with at least one of the plurality of blades to regulate the opening operation of these blades.

[0155]

As described above, according to the present invention, in a light-shielding device having four light-shielding blades, the aperture is displaced in association with the zooming function of the image-taking optical system to apply the image-taking optics to be applied. An object of the present invention is to provide a light-shielding device that can secure good opening accuracy of an opening portion in an open state without deteriorating the optical performance of the system, and can contribute to downsizing of an applicable photographing optical system.

Further, it is possible to provide a light-shielding device capable of surely preventing an exposure accident or the like to a film caused by the light-shielding device being inadvertently opened.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a lens barrel having a photographing optical system such as a camera to which a light shielding device according to a first exemplary embodiment of the present invention is applied.

FIG. 2 is a diagram illustrating a detailed configuration of the light shielding device of FIG. 1 and an operation thereof, showing a closed state in which an opening of the light shielding device is shielded by a plurality of light shielding blades.

FIG. 3 is a diagram illustrating a detailed configuration of the light shielding device of FIG. 1 and an operation thereof, showing an open state in which a plurality of light shielding blades of the light shielding device are retracted outside an opening.

4 is a diagram showing a schematic configuration of the light shielding device of FIG. 1 described above, which is an enlarged longitudinal sectional view of an essential part showing an enlarged vicinity of the light shielding device in FIG.

FIG. 5 is a schematic view of the light-shielding device base portion supporting the light-shielding device of FIG. 1 as viewed from the blade drive lever side.

6 is a diagram showing a positional relationship between the opening opening variable ring and the blade drive lever when the magnification changing operation is performed by the photographing optical system of FIG. 1, and the photographing optical system is on the telephoto side. The figure which shows the state of the opening opening variable ring at this time.

7 is a diagram showing the positional relationship between the open aperture variable ring and the blade drive lever when the magnification changing operation is performed by the photographing optical system of FIG. 1, and the photographing optical system is on the wide-angle side. The figure which shows the state of the opening opening variable ring at this time.

8 is a view conceptually showing the operation of the blade drive lever and the operation of the pair of inner blades and the pair of outer blades of the light shielding device of FIG. 1 from the fully closed state to the fully opened state of the opening. The figure which showed the change.

9 is a view conceptually showing the operation of the blade drive lever and the operation of the pair of inner blades and the pair of outer blades of the light shielding device of FIG. 1, wherein the blade drive lever is positioned by the open opening variable cam. The figure which shows the state at the time of being prescribed.

FIG. 10 is a diagram for explaining the configuration and operation of the light shielding device of the second embodiment of the present invention, showing the closed state in which the opening of the light shielding device is shielded by a plurality of light shielding blades.

FIG. 11 is a diagram for explaining the configuration and operation of the light shielding device of FIG. 10 above, showing an open state in which a plurality of light shielding blades of the light shielding device are retracted outside the opening.

FIG. 12 is an enlarged view of a main part showing the vicinity of an outer blade cam formed in the outer blade of the light shielding device of FIG. 10 in an enlarged manner.

13 is a diagram conceptually showing the operation of the pair of inner blades and the pair of outer blades with respect to the operation of the blade drive lever of the light shielding device of FIG. 10, from the fully closed state to the fully opened state of the opening. The figure which shows change.

14 is a view conceptually showing the operation of the pair of inner blades and the pair of outer blades with respect to the operation of the blade drive lever of the light shielding device of FIG. 10, in which the blade drive lever defines the position by the open side stopper portion. The figure which shows the state at the time of being performed.

FIG. 15 is a vertical cross-sectional view of a lens barrel having a photographing optical system such as a camera to which the light shielding device of the third embodiment of the invention is applied.

16 is a view showing the light-shielding blades and the like constituting the light-shielding device of FIG. 15 and is a diagram showing a closed state in which the opening is shielded by a plurality of light-shielding blades.

FIG. 17 is a view showing a light shielding device according to another embodiment of the present invention, showing the closed state of the light shielding blades.

FIG. 18 is a diagram showing an open state of the light shielding blade in the light shielding device of FIG. 17;

[Explanation of symbols]

1 ... 1st group lens (shooting optical system) 2 ... 2nd group lens (shooting optical system) 3 ... 1st lens holding frame 4 ... 2nd lens holding frame 13a, 13d ... Cam groove (outer blade) Cams 13b, 13c ... Cam grooves (inner blade cams) 16 ... Openings 17,30 ... Shading devices 17a, 17Aa, 17Ba, 17d, 17Ad, 17
Bd ... A pair of outer blades (light-shielding blades) 17b, 17Ab, 17c, 17Ac ... A pair of inner blades (light-shielding blades) 19 ... Blade drive lever 20 ... Drive pin 22 ... Biasing spring (biasing means) 31 ... Ring member for opening / closing the light shielding blade

Claims (3)

[Claims] 1. When the lens is opened and closed by being rotated about a predetermined axis, and when in a closed state, at least a light beam in the vicinity of the optical axis of the photographing light beam passing through the photographing optical system is shielded and is in an open state. In this case, it is retracted from the path through which the photo-taking light flux passes,
Multiple inner blades, which are opened and closed by rotating around a predetermined axis, and when in the closed state, mainly shield the peripheral light flux of the shooting light flux that passes through the shooting optical system, and open it. In this case, the positions of the outer blades and the outer blades that are retracted from the passage of the photographing light flux and substantially overlap with the inner blades are defined, and the positions of the outer blades in the open state are defined. A light-shielding device, comprising: a position defining means for changing the position in association with a zooming operation of an optical system. 2. When it is opened and closed by being rotated about a predetermined axis, and when it is in a closed state, at least a light flux near the optical axis of the photographing light flux passing through the photographing optical system is shielded and is in an open state. In this case, it is retracted from the path through which the photo-taking light flux passes,
Multiple inner blades, which are opened and closed by rotating around a predetermined axis, and when in the closed state, mainly shield the peripheral light flux of the shooting light flux that passes through the shooting optical system, and open it. When there is a plurality of outer blades that are retracted from the path of passage of the imaging light flux and substantially overlap with each of the plurality of inner blades, the plurality of inner blades and the plurality of outer blades are provided. The moving amount and moving speed of each blade when opening and closing are
The inner blades of the plurality of sheets are set to be larger, and the inner blades of the plurality of sheets move over the plurality of outer blades during the opening operation, and the outer circumference of the photographing light flux in the open state is the outer side of the plurality of sheets of the outer blades. A shading device characterized by being determined by an inner edge of a blade. 3. When it is opened and closed by being rotated about a predetermined axis, and when it is in a closed state, at least a light flux near the optical axis of the photographing light flux passing through the photographing optical system is shielded and is in an open state. In this case, it is retracted from the path through which the photo-taking light flux passes,
Multiple inner blades, which are opened and closed by rotating around a predetermined axis, and when in the closed state, mainly shield the peripheral light flux of the shooting light flux that passes through the shooting optical system, and open it. , The blade driving lever is provided on each of the plurality of outer blades and the plurality of inner blades that are retracted from the passage of the photographing light flux and substantially overlap with each of the plurality of inner blades. Is provided in each of the inner blade cam and the outer blades, which are always cam-coupled with each other to transmit the driving force of the blade drive lever to the inner blades, and the blades are provided only at the initial stage of the opening operation. An outer blade cam that is cam-coupled to the drive lever, and an urging unit that urges each of the plurality of outer blades in the opening direction and moves the plurality of outer blades after the initial opening operation. A light-shielding device comprising: