JP2869868B2 - Shading blade device for camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is applied to a light shielding blade device used for a shutter or a diaphragm of a still camera. More specifically, it is arranged so as to be able to run along a running surface parallel to the opening, and is composed of a plurality of blades which can be retracted in directions opposite to each other with respect to the opening. And a light-shielding blade device having a light-shielding blade group.

[Conventional technology]

Recent still cameras, especially compact cameras, are mainly composed of a so-called bifocal camera having two different focal lengths and having a selectable lens, and a so-called zoom camera having a variable focal length lens, and further having a variable focal length. High-magnification zoom cameras with magnifications of 3x and 4x have begun to spread.

By the way, in a zoom camera, since the aperture diameter of the optical path remains almost unchanged, the higher the zoom ratio becomes, the larger the full aperture F value at the long focal length becomes compared to the full aperture F value at the short focal length. System darkens. F at long focus
As the value increases, for example, in the single-lens reflex system, the finder becomes darker. In view of these points, recent compact cameras tend to reduce the F-number of the lens and make the optical system as bright as possible due to market requirements. In order to reduce the F value, the aperture of the lens must be naturally increased if the focal lengths are the same.

In such a compact camera, a light-shielding blade device that slides a pair of light-shielding blades in directions opposite to each other with respect to a lens opening to open and close the opening has been widely used. This type of apparatus can control the aperture time and aperture through the blade itself, and is small and lightweight, and thus has been frequently used in compact cameras.

However, in such a light-shielding blade device, when the diameter of the opening is increased, the size of the blade for closing and closing the opening must be necessarily increased. In this case, when the opening is fully opened, the pair of blades are retracted to both sides of the opening. However, since the size of each blade is large, the planar spread of the blades is inevitable and the outer diameter of the light-shielding blade device is increased. There were difficulties. In this type of device, the outer diameter of the light-shielding blade device must be increased substantially in proportion to the inner diameter of the opening. In view of the fact that the outer diameter of the light-shielding blade device substantially defines the size of the entire compact camera, such a problem is significant for the market demand for reducing the lens F value without increasing the size of the compact camera. Was a major obstacle.

In view of the difficulties of the conventional light-shielding blade device described above,
-526 discloses an improved shading vane device. In this type of shading blade device, the inner diameter of the opening can be increased without increasing the outer diameter of the device. That is, in this type of light-shielding blade device, each of a pair of blades, which was conventionally one, is divided into two blades, an outer blade and an inner blade. When the opening is fully closed, the opening is completely closed while overlapping each other. However, when the opening is fully opened, it is stored while overlapping with the annular portion sandwiched between the inner diameter end of the opening and the outer diameter end of the light shielding blade device. That is, in this case, four light-shielding blades which are originally composed of two sheaves are arranged so as to overlap each other when viewed two-dimensionally.

[Problems to be solved by the invention]

However, the light-shielding blade device disclosed in Japanese Patent Application Laid-Open No. Sho 64-526 has a structure in which four light-shielding blades are rotatably locked by a common rotation shaft around the opening. Each light-shielding blade is moved by four operating pins. Since the four operating pins are arranged close to each other, each light-shielding blade must be provided with a notch in order to avoid the movement trajectory of the dense operating pins, and the shape must be complicated. . For this reason, the outer shape of the light-shielding blade is greatly restricted, which is a problem.

[Means to solve the problem]

The present invention has been made in view of the above-described conventional problems, and has as its object to provide an improved light-shielding blade device that has light-shielding blades whose shape can be easily designed and that can be further reduced in size.

To achieve the above object, the light-shielding blade device of the present invention
A substrate including a central portion provided with an opening and a pair of peripheral portions symmetrically positioned with respect to the center of the opening; and a pair of fulcrums spaced apart from each other at a peripheral portion of one substrate so as to be rotatable around each of the fulcrums. A pair of aperture forming blades which are arranged and can be retracted in the opposite direction from the opening, and a pair of fulcrums spaced apart from each other, which are set to be larger than the fulcrum distance of the aperture forming blade in the other substrate peripheral portion. A pair of opening covering blades rotatably disposed around the opening and retreating from the opening in opposite directions, an opening forming blade and an opening covering blade arranged so as not to exceed the outer peripheral edge of the substrate. Are operated in conjunction with each other to open and close the opening.

Preferably, the operating mechanism includes one operating lever for operating the opening forming blade, another operating lever for operating the opening covering blade, and a connection forming an operating mechanism of a link connecting the pair of operating levers. It comprises a member and a rotation drive source for driving the connecting member.

More preferably, the light-shielding blade device according to the present invention has a two-layer blade chamber divided in parallel to the substrate plane,
Each of the blade chambers stores a pair of an opening forming wing and an opening covering blade which are overlapped with each other in the retracted state.

[Action]

According to the present invention, when the light-shielding blade device is in the closed state of the opening, the four light-shielding blades including the pair of the opening forming blades and the pair of the opening covering blades partially overlap each other to complement and completely block the opening. It is closed. When the operating mechanism is operated in this state, the pair of opening forming blades retreats from the opening in opposite directions, and at the same time, the pair of opening covering blades also retreats from the opening in the opposite direction. As a result, the opening is opened, and the light-shielding blade device shifts to the open state. Conversely, to return from the open state to the closed state, the operating mechanism may be operated in the opposite direction. Through these series of operations, the lens opening and closing are performed for each exposure.

Embodiments Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, upper, lower, left and right characters are used for the names, positions, and operation directions of the individual components of the light shielding blade device. These upper, lower, left, and right notations are used with reference to the front side of the substrate plane of the light-shielding blade device, and are merely convenient for describing the embodiments of the present invention with reference to the drawings. Therefore, these notations do not limit the actual product configuration in any way.

FIG. 1 is a front side plan view of a light-shielding blade device according to the present invention, and shows a state in which an opening is closed. The substrate 1 includes a central portion where the opening 2 is provided and a pair of upper and lower peripheral portions symmetrically positioned with respect to the center of the opening 2. A lower left fulcrum shaft 3 and a lower right fulcrum shaft 4 are spaced apart from each other at a lower peripheral portion of the substrate 1. The left opening forming blade 5 is rotatably locked to the lower left fulcrum shaft 3. The right opening forming blade 6 is rotatably locked to the corresponding lower right fulcrum shaft 4.
The pair of opening forming blades 5 and 6 are arranged so as to substantially overlap the central portion of the opening 2 in the closed state, and are rotatable in opposite directions. As they rotate, they separate from each other and define the effective aperture between them. That is, the pair of opening forming blades 5 and 6 have a function of forming an effective opening. A long line 7 is formed on the left opening forming blade 5, and a long line 8 is also formed on the right opening forming blade 6. The lengths 7 and 8 overlap each other, and the lower operation pin 9 is inserted. The lower operation pin 9 moves along the locus indicated by the arrow A and rotates the pair of opening forming blades 5 and 6 in directions opposite to each other. In the illustrated closed state, the lower operation pin 9 is held at the start point position.

The upper left fulcrum shaft 10 is spaced apart from the upper peripheral portion of the substrate 1.
And an upper right fulcrum shaft 11 is implanted. A left opening cover blade 12 is rotatably locked to the upper left fulcrum shaft 10, and a right opening cover blade 13 is rotatably locked to the upper right fulcrum shaft 11. The pair of opening covering blades 12 and 13 are located around the opening 2 of the substrate 1 in the closed state, and the pair of opening forming blades 5 and 6 cover the periphery of the opening 2 that is not closed. That is, the pair of opening covering blades 12 and 13 complement the pair of opening forming blades 5 and 6. Left opening cover feather 12
A long groove 15 is formed in the right opening covering blade 13. The long grooves 14 and 15 overlap each other, and the upper operation pin 16 is inserted. As shown, the upper operation pin 16 moves along a locus indicated by an arrow B, and can rotate the pair of opening covering blades 12 and 13 in directions opposite to each other. In the closed state of the opening, the upper operation pin 16 is held at the start point position. By the upper operation pin 16, the pair of opening cover blades 12 and 13 rotate symmetrically with each other. Further, the pair of opening covering blades 12 and 13 have outer diameter shapes that are symmetrical to each other. Therefore, substantial parts can be reduced. Similarly, the left opening forming blade 5 and the right opening forming blade 6 have symmetric outer diameter shapes. However, the fulcrum distance of the opening covering blade is set to be larger than the fulcrum distance of the opening forming blade. This is because the amount of rotation of the opening covering blade between the closed state and the open state of the opening is smaller than the amount of rotation of the opening forming blade. further,
The component that opens to the aperture covering blade and the component that opens to the aperture forming blade open to the optical axis passing through the center of the opening 2 and are arranged substantially symmetrically with each other.

FIG. 1B is a plan view of the surface of the light-shielding blade device according to the present invention, showing an open state of the opening. As shown in the drawing, the lower operation pin 9 moves downward according to the trajectory A and is held at the end position. By this operation, the left opening forming blade 5 rotates clockwise about the lower left fulcrum shaft 3 and is retracted on the right substrate of the opening 2. Similarly, the right opening forming blade 6 is rotated counterclockwise about the corresponding lower right fulcrum shaft 4 and retracted on the left substrate of the opening 2.

The upper operation pin 16 also moves downward along the locus B in conjunction with the lower operation pin 9 and is held at the end position. By this operation, the left opening covering blade 12 rotates clockwise around the corresponding upper left fulcrum shaft 10 and is retracted on the left substrate of the opening 2. Similarly, the right-opening cover blade 13 rotates counterclockwise about the corresponding upper-right fulcrum shaft 11 and is retracted on the right substrate of the opening 2. As a result, the four blades have the opening 2
And the opening 2 is in an open state.

FIG. 2A is a plan view of the back surface of the light-shielding blade device, and shows a closed state of the opening. That is, it is a view of the substrate 1 shown in FIG. 1A as viewed from the back side. A lower rotating shaft 17 is implanted in a lower peripheral portion of the substrate 1. A lower operating lever 18 is rotatably locked to the lower rotating shaft 17. The lower operation pin 9 is fixed to the tip of the lower operation lever 18. As described above, the lower operation pin 9 penetrates through the substrate 1 and protrudes to the front side, and is inserted into the long grooves 7 and 8 formed in the pair of opening forming blades 5 and 6. The lower operation pin 9 also protrudes on the side opposite to the blade.

An upper rotation shaft 19 is implanted in an upper peripheral portion of the substrate 1. An upper operation lever 20 is rotatably locked to the upper rotation shaft 19. An upper operation pin 16 is fixed to a tip of the upper operation lever 20. As described above, this upper working pin
Reference numeral 16 penetrates through the substrate 1 and projects to the front side. And it is inserted in the long courses 14 and 15 formed on the pair of opening covering blades 12 and 13. The upper operation pin 16 also protrudes on the side opposite to the blade. A connecting member 21 is engaged with the projections of the lower operation pin 9 and the upper operation pin 16. The connecting member 21 has a substantially arc shape. At a substantially central portion of the connecting member 21, a long course 22 is formed. The drive pin 23 is inserted in the long groove 22. The drive pin 23 moves along a locus indicated by an arrow C.
In the closed state of the opening, the drive pin 23 is held at the start point of the movement locus. The lower operating lever 18, the upper operating lever 20, and the connecting member 21 constitute an operating mechanism of the parallel link. Actuating lever through this parallel link
When the pins 18 and 20 are actuated and the driving pin 23 is at the starting position, the operating pins 9 and 16 are also held at the starting position.

FIG. 2B is a plan view of the back surface of the light-shielding blade device, showing an open state of the opening. That is, it is a view of the substrate shown in FIG. 1B viewed from the back side. As shown, the four blades are completely retracted from the opening 2. In the open state, the drive pin 23 is held at the end position along the movement path C. With this operation, the lower operation pin 9 is held at the end point position, and the pair of opening forming blades 5 and 6 rotate in opposite directions to each other and are retracted from the opening 2. Similarly, the upper operation pin 16 is also held at the end point position, and the pair of opening covering blades 12 and 13 are rotated in opposite directions to each other and retracted from the opening 2.

As is clear from FIGS. 2A and 2B, the operating mechanism composed of the parallel link is housed in the ring-shaped peripheral portion of the substrate 1. As is clear from FIG. 1B, the four light-shielding blades are also housed in a state where the opening is closed and are superimposed on each other around the ring-shaped peripheral portion of the substrate 1. Therefore, the light-shielding blade device according to the present invention has an extremely compact shape.

FIG. 3A shows the operating pin 9 of the lower operating lever 18 and the rotating shaft.
It is sectional drawing of the light-shielding blade apparatus cut | disconnected by the straight line passing through 17. FIG. As shown in the figure, the substrate 1 is covered by a shutter frame 24 from the front side and supported by a link presser 25 from the back side. The space between the substrate 1 and the shutter frame 24 is partitioned by an intermediate plate 26 to form two layers of blade chambers divided in parallel. Each of the blade chambers stores a pair of an opening forming blade and an opening covering blade which are in a mutually overlapping relationship in the retracted state. That is, in the blade chamber on the side of the shutter frame 24, a set of the opening forming blade 6 and the opening covering blade 12 retreated to the left with respect to the opening 2 is stored.
The opening forming blade 5 and the opening covering blade 13 retracted to the right with respect to the opening 2 are accommodated in the blade chamber on the side of. In this way, by storing the four blades separately in two sets, it is possible to prevent interference and street collision during running of the blades. In particular, in each blade chamber, a set of blades retreated in the same direction is stored, so that the possibility of interference or collision occurring in the blade chamber is reduced. A pair of fulcrum shafts 3 and 4 are implanted on the front side of the substrate 1. The fulcrum shaft 3 supports one opening forming blade 5, and the other fulcrum shaft 4 supports the other opening forming blade 6. A rotating shaft 17 is implanted on the back side of the substrate 1, and an operating lever 18 is rotatably supported on the rotating shaft 17. An operating bin 9 is integrally formed at the tip of the operating lever 18. The opening forming blades 5 and 6 are engaged with one end of the operating pin 9, and the connecting member 21 is engaged with the other end. The connecting member 21 is a link presser with the substrate 1.
It is located in a space between 25. In order to prevent the connection member 21 from floating, both surfaces thereof may be slidably supported by a guide member.

FIG. 3B is a sectional view of the light-shielding blade device cut along a straight line connecting the drive pin 23 and the center of the opening 2. As shown, the drive pin 23 is inserted into the long groove 22 of the connecting member 21 through the link retainer 25. The drive pin 23 is directly connected to a drive source 27 mounted on the link presser 25. As the drive source 27, for example, a stepping motor or a moving magnet actuator is used. The drive source 27 is preferably of a small size, and does not protrude from both ends of the ring-shaped portion of the substrate 1. In this embodiment, the driving pin 23 directly connects the connecting member.
By driving 21, a pair of operating levers 18 and 20 are operated. However, the present invention is not limited to this. For example, one of the pair of operating levers may be driven by a driving source.

〔The invention's effect〕

As described above, according to the present invention, since the pair of opening forming blades and the pair of opening covering blades are pivotally supported on opposite sides with respect to the opening, compared with the conventional light shielding blade device. The light-shielding blades can be stored more compactly. In other words, there is an effect that the aperture diameter can be made larger and the substrate outer diameter can be made smaller as compared with the conventional light shielding blade device. Also, as the opening forming blade and the opening covering blade are vertically separated from each other with respect to the opening 2, the operating pin for moving the blade can also be separated vertically, so that the operation is performed like the conventional light shielding blade device. There is also an effect that it is not necessary to form a notch having a complicated shape in the light shielding blade in order to avoid the pin. In addition, since the pair of opening forming blades run at the same time by the common operating pin, there is also an effect that the play is reduced and the exposure accuracy is improved as compared with the related art.

[Brief description of the drawings]

1A is a plan view of the light-shielding blade device viewed from the front side, showing an open state, FIG. 1B is a plan view of the light-shielding blade device also viewed from the front side, and FIG. 2A is an open state. FIG. 2B is a plan view of the light-shielding blade device as viewed from the rear side, showing the closed state of the opening.
FIG. 3A is a plan view of the light-shielding blade device similarly viewed from the back side, showing an open state, and FIG. 3A is a partial cross-sectional view of the light-shielding blade device taken along a line connecting the operating pin and the rotating shaft.
FIG. 4 is a partial cross-sectional view of the light-shielding blade device, which is also cut along a line connecting the center of the opening and the drive pin. DESCRIPTION OF SYMBOLS 1 ... Board, 2 ... Opening 3 ... Lower left fulcrum axis, 4 ... Lower right fulcrum axis 5 ... Left opening forming wing, 6 ... Right opening forming wing 9 ... Lower working pin, 10 ... Upper left fulcrum axis 11 ... Upper right fulcrum axis, 12 ... left-opening cover blade 13 ... right-opening cover blade, 16 ... upper operating pin 17 ... lower rotating shaft, 18 ... lower operating lever 19 ... upper rotating shaft, 20 ... upper operating lever 21 ... connecting member, 23 ... Drive pins 24 ... Shutter frame, 25 ... Link presser 26 ... Intermediate plate, 27 ... Drive source

Claims (3)

(57) [Claims] A substrate including a central portion provided with an opening and a pair of peripheral portions symmetrically positioned with respect to a center of the opening; and a pair of fulcrums spaced apart from each other at a peripheral portion of one of the substrates. And a pair of opening forming blades that are rotatably disposed in the opposite direction from the opening, and are separated from each other at a peripheral portion of the other substrate that is set to be larger than a fulcrum distance of the opening forming blade. A pair of aperture covering blades rotatably arranged around each of the pair of fulcrums, which are retractable in opposite directions from the aperture, and an aperture arranged so as not to exceed the outer peripheral edge of the substrate. An operating mechanism for operating the forming blade and the opening covering blade in conjunction with each other to open and close the opening; The operating mechanism includes an operating lever for operating the opening forming blade, another operating lever for operating the opening covering blade, and an operation of a link connecting the pair of operating levers. The light-shielding blade device according to claim 1, further comprising a connecting member that constitutes a mechanism, and a rotation drive source that drives the connecting member. 3. It has two layers of blade chambers divided in parallel,
2. The light-shielding blade device according to claim 1, wherein each of the blade chambers stores therein a pair of an opening forming blade and an opening covering blade which are overlapped with each other in the retracted state.