Sector drive apparatus for use in optical apparatus

A sector drive apparatus for use in an optical apparatus, the sector drive apparatus includes a sector having a first engagement opening engaged with an operation member that reciprocates in a given range and a second engagement opening engaged with a spindle fixed to a shutter substrate, the sector opening and closing a shutter opening formed in the shutter substrate in accordance with a movement of the operation member. The operation member has an engagement pin that is engaged in the first engagement opening, the first engagement opening is substantially circular that permits the operation member to rotate, and the second engagement member is an elongate opening, and swings the sector centering around the spindle to move to a position where the shutter opening is opened and closed, when the first engagement opening moves in accordance with the movement of the operation member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to sector drive apparatuses for use in optical apparatuses, and more particularly, to a sector drive apparatus for use in an optical apparatus such as a digital camera housed in a mobile telephone, a camcorder, or the like.

2. Description of the Related Art

In recent years, cameras have been downsized at a remarkable speed, and the shutter speed has been increased. In order to downsize the camera and increase the shutter speed, there is a need that internal parts have to be more compact and efficiently configured. For instance, Japanese Patent Application Publication 2002-139768 (hereinafter, referred to as Document 1) discloses the sector drive apparatus in which the shapes of sectors are formed small and multiple sectors operate together to close the shutter opening. With such sector drive apparatus, it is possible to promote downsizing.

FIG. 6AandFIG. 6Bshow the conventional sector drive apparatus disclosed in Document 1.FIG. 6Ashows a shutter opening10ain a fully open state.FIG. 6Bshows a state in process of closing the shutter opening10a. In this sector drive apparatus, three sectors121,122, and130are rotatably provided on a shutter substrate110. The sectors121and122are aperture blades and the sector130is a shutter blade. The aperture blades121and122are driven by an operation pin141asimultaneously. These aperture blades overlap each other, and this makes it difficult to see the movements thereof. Hence, the shutter blade130is described, because the shutter blade130has a similar configuration and is composed of a single blade. It is therefore easier to see the movement of the shutter blade130.

The shutter blade130includes a circular opening131and an elongate opening132. The circular opening131is engaged with a spindle113fixed to the substrate. Therefore, the shutter blade130is pivotally provided about the spindle113. An operation pin151ais engaged with the elongate opening132. The operation pin151ais connected to a rotor151of the drive motor150, and rotates within a given range. Accordingly, the shutter blade130rotates around the spindle113by means of the driving force of the operation pin151ato open and close the shutter opening10a.

The sector included in the conventional sector drive apparatus generally has two engagement openings as in the afore-described shutter blade130. The first engagement opening131is engaged with the spindle113fixed to the shutter substrate110. The second engagement opening132is engaged with the operation pin151a. As shown inFIG. 6AandFIG. 6B, the opening131engaged with the spindle113fixed to the substrate is formed to have a shape of a perfect circle having an inner diameter slightly greater than the spindle. On the other hand, the opening132engaged with the operation pin151ahas a shape of an elongate hole. The operation pin151aslides inside the opening132to transmit the driving force.

As shown inFIG. 6AandFIG. 6B, conventionally, the engagement opening132with which the operation pin151ais engaged is formed to have a shape of an elongate hole. When the operation pin151ainternally slides the elongate opening132, the shutter blade130rotates around the spindle113and moves within a range for opening and closing the shutter opening10a.

Conventionally, the opening with which the operation pin is engaged has a shape of an elongate hole. Therefore, as shown inFIG. 6AandFIG. 6B, the elongate opening132provided in the sector needs to be designed in such a manner that the operation pin151ais in contact with the inner wall thereof with no margin. Specifically, the elongate opening is designed to extend in a direction that crosses a moving direction of the operation pin151a. The elongate opening132having a large area is arranged at a position away from the spindle113, which is the rotation center of the sector. Therefore, when the sector rotates, a rotational area near the elongate opening132is large. Therefore, another spindle that is the rotation center of another sector needs to be situated to avoid the afore-mentioned rotational area. This makes it difficult to downsize the sector drive apparatus.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a small-sized sector drive apparatus.

The afore-mentioned object can be achieved by a sector drive apparatus for use in an optical apparatus, the sector drive apparatus including: a sector having a first engagement opening engaged with an operation member that reciprocates in a given range and a second engagement opening engaged with a spindle fixed to a shutter substrate, the sector opening and closing a shutter opening formed in the shutter substrate in accordance with a movement of the operation member. The operation member has an engagement pin that is engaged in the first engagement opening; the first engagement opening is substantially circular that permits the operation member to rotate; and the second engagement member is an elongate opening, and swings the sector centering around the spindle to move to a position where the shutter opening is opened and closed, when the first engagement opening moves in accordance with the movement of the operation member.

Similarly, the afore-mentioned object can also be achieved by a sector drive apparatus for use in an optical apparatus, the sector drive apparatus including: multiple sectors, each of said multiple sectors having a first engagement opening engaged with an operation member that reciprocates in a given range and a second engagement opening engaged with a spindle fixed to a shutter substrate, said multiple sectors opening and closing a shutter opening formed in the shutter substrate in accordance with a movement of the operation member. The operation member has an engagement pin that is engaged in the first engagement opening; the first engagement opening of at least one of said multiple sectors is substantially circular that permits the operation member to rotate; and the second engagement member is an elongate opening, and swings the sector centering around the spindle to move to a position where the shutter opening is opened and closed, when the first engagement opening moves in accordance with the movement of the operation member.

Further, the afore-mentioned object can also be achieved by an optical apparatus including the afore-described sector drive apparatus.

In accordance with the present invention, provided are the elongate opening that has a large area near the rotation center of the sector and the engagement opening that does not need such a large area to be engaged with the operation member. This enables the rotational area to be smaller necessary for rotating the sector. Accordingly, the rotation centers of other sectors can be arranged closer, enabling the sector drive apparatus to be downsized. The sector is made to move in a desired trajectory instead of a simple circular motion, by arranging the elongate opening in an appropriate shape. It is thus possible to make the rotational area of the sector smaller, thereby contributing to the downsizing of the sector drive apparatus.

Preferably, all the sectors are driven by a single operation member. With this configuration, it is possible to provide the efficient sector drive apparatus in which a single operation member can drive all the sectors.

In accordance with the present invention, the sector drive apparatus can be downsized.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will now be given, with reference to the accompanying drawings, of a sector drive apparatus in accordance with embodiments of the present invention.FIG. 1throughFIG. 5show a sector drive apparatus10in accordance with embodiments of the present invention.FIG. 1is a view showing sectors in a fully open state in the sector drive apparatus10. On the upper side of the figure, the state of a stepping motor1is also shown as an example of a drive portion that drives the respective sectors.FIG. 2AthroughFIG. 2Dshow portions of the structure included in the sector drive apparatus10shown inFIG. 1.FIG. 3AandFIG. 3Bshow the whole configuration including a drive mechanism of the sector drive apparatus10.FIG. 4is a view showing the sector drive apparatus10in a fully closed state.FIG. 5is a view showing the sector drive apparatus10in a small aperture state.

First, referring to a lower figure inFIG. 1, sectors included in the sector drive apparatus are described. The sector drive apparatus10includes three sectors. The sector drive apparatus10includes a shutter substrate50and three sectors60,65, and70. The sector60is a first shutter blade, and the sector65is a second shutter blade. The sector70is an aperture blade having a small aperture opening75. A shutter opening51is formed in the center of the shutter substrate50.

FIG. 2AthroughFIG. 2Dare views showing the respective structures of the stepping motor1shown inFIG. 1.FIG. 2Ashows the first sector60,FIG. 2Bshows the second sector65, andFIG. 2Cshows the third sector70.FIG. 2Dis an enlarged view of a given range RE in which an operation pin27moves as an operation member. The operation pin27is driven by the stepping motor1. The relationship between the stepping motor1and the operation pin27and the relationship between the stepping motor1and the respective sectors to be moved by the operation pin will be described later in detail, with reference toFIG. 3AandFIG. 3B.

The shapes of the respective sectors are described, with reference toFIG. 2AthroughFIG. 2D. The sector drive apparatus10includes the first sector60and the third sector70respectively having engagement openings different from those in the conventional sector. First, the first sector60shown inFIG. 2Aincludes two engagement openings62and63. The first engagement opening63is substantially circular and engaged with the operation pin27. The engagement opening63has an inner diameter that is formed slightly greater than the operation pin27, so that the operation pin27is rotatably provided therein. On the other hand, the second engagement opening62is formed to be an elongate opening having a curvature. A spindle61fixed to the substrate50is engaged with the elongate opening62.

As described, the first sector60has the engagement openings provided in a reverse state from the conventional one. That is to say, the engagement opening63with which the operation pin27is engaged is formed to have a shape of a circle that permits the operation pin27to rotate. Also, the engagement opening62with which the spindle61is engaged is an elongate opening. Provided are the engagement opening62of an elongate hole that needs a large area and a thickness portion60athat surrounds the engagement opening62near the spindle61of the rotation center. Also provided are the engagement opening63that needs only a small area and a thickness portion60bthat surrounds the engagement opening63near the operation pin27. Hence, when the first sector60is made to rotate, an area necessary for rotating near the operation pin27is decreased, making it possible to arrange another spindle that is the rotation center of another sector to be closer by the decrease. Thus, it is possible to bring spindles, which are the rotation centers of the sectors, closer to each other and bring the sectors closer to each other, thereby enabling the whole apparatus to be downsized. Also, the engagement opening62is formed to have a curved shape as necessary. This allows the sector60to move around the spindle61in a rotational direction due to a simple rotary motion of the sector60, and in addition, allows the sector60to move in a direction other than the rotational direction. The rotational area necessary for the rotational direction can be made smaller, thereby enabling the whole apparatus to be small-sized. The elongate opening62is designed to swing the sector60so as to open and close the shutter opening51, when the engagement opening63moves according to the movement of the operation pin27. The shape of the elongate opening62is configured to be curved or linear, as required, in consideration of an outer shape of the sector60, so that the sector60moves efficiently to the position where the sector60opens and closes the shutter opening51in accordance with the movement of the operation pin27. The operation pin27is not engaged with the elongate opening62. This eliminates the restriction in design as seen in the conventional one, and realizes a flexible design of the shape.

FIG. 2Bshows the third sector70. The third sector70having the small aperture opening75has a same configuration as that of the first sector60. That is to say, the third sector70includes two engagement openings72and73. The first engagement opening73is substantially circular and engaged with the operation pin27. On the other hand, the second engagement opening72is formed to be an elongate hole. A spindle71fixed to the substrate50is engaged with the elongate opening72. The third sector70also has the engagement openings in a reverse state from the conventional one. Provided are the engagement opening72of an elongate hole that needs a large area and a thickness portion70athat surrounds the engagement opening72near the spindle71of the rotation center. Also provided are the engagement opening73that needs only a small area and a thickness portion70bthat surrounds the engagement opening73near the operation pin27. Hence, when the third sector70is made to rotate, an area necessary for rotating near the operation pin27is decreased. This makes it possible to arrange another spindle of the rotation center of another sector closer by the decrease. Thus, it is possible to bring spindles, which are the rotation centers of the sectors, closer to each other so as to bring the sectors closer to each other, thereby enabling the whole apparatus to be downsized. Also, the engagement opening72is formed to have a linear shape as necessary. This allows the sector70to move around the spindle71in a rotational direction due to a simple rotary motion of the sector70and to move in a direction other than the rotational direction. The rotational area that needs the rotational direction can be made smaller, thereby enabling the whole apparatus to be small-sized. Accordingly, when the engagement opening73moves according to a movement of the operation pin27, the sector70rotates efficiently to move to a position where the sector70opens and closes the shutter opening51.

Meanwhile, the second sector65shown inFIG. 2Cis configured to have conventional engagement openings. That is to say, the second sector60includes two engagement openings67and68. The first engagement opening68has a shape of an elongate hole, and is engaged with the operation pin27. On the other hand, the second engagement opening67is formed to have a circular shape, and a spindle66fixed to the substrate50is engaged in the engagement opening67. Hence, in accordance with the movement of the operation pin27in the elongate opening68, the sector65swings and moves to a position where the shutter opening51is opened and closed.

As described heretofore, the sector drive apparatus10is configured to realize a small-sized sector drive apparatus by combining the first sector60, the third sector70having the engagement openings arranged reversely from those of the conventional sector, and the second sector65having the conventional configuration of engagement openings. In the description hereafter, the drive portion included in the sector drive apparatus10will be shown and the operations of the sectors60,65, and70will be described.

FIG. 3Ais a plan view of a whole structure of the sector drive apparatus10. The sector drive apparatus10has the stepping motor1on the back side of the shutter substrate50. The stepping motor1includes a rotor2and a stator3. The rotor2is arranged in the center and rotatably provided in both directions. The stator3is arranged to face the outside of the rotor2. The rotor2has a cylindrical shape, and has a circular shape at cross section. The stator3has a C-shaped planar shape and is integrally formed, and houses the rotor2in an internal space thereof. On the upper side ofFIG. 1, the stepping motor1is shown in such a manner that open ends of C shape in the stator3face upwardly.

The rotor2has four magnetic poles, which include two North magnetic poles and two South magnetic poles. The rotor2is a permanent magnet where identical magnetic poles are positioned to face each other, and is rotatably provided around an axis21in both directions. Both ends of the stator3having the afore-described C shape are formed to face the circumferential surface of the rotor2. These ends respectively serve as a first magnetic pole11and a second magnetic pole12. A third magnetic pole13is arranged in an intermediate position between the first magnetic pole11and the second magnetic pole12.

A first coil4is wound between the first magnetic pole11and the third magnetic pole13, and a second coil5is wound between the second magnetic pole12and the third magnetic pole13. The first magnetic pole11is magnetically excited when current is applied to the first coil4, and the second magnetic pole12is magnetically excited when current is applied to the second coil5. On the other hand, the third magnetic pole13is magnetically excited by both the first coil4and the second coil5.

On the front side of the shutter substrate50, the above-described three sectors60,65, and70are provided along the substrate surface. These sectors are a first shutter blade60, a second shutter blade65, and an aperture blade70, from the shutter substrate side. The stepping motor1is positioned on the back side of the shutter substrate50.

The openings cannot be confirmed inFIG. 3A, however, the first sector60includes the elongate opening62and the circular opening63, the elongate opening62being engaged with the spindle61provided in the substrate50, the circular opening63being engaged with the operation pin27that extends from the rotor2. Similarly, the third sector70includes the elongate opening72and the circular opening73, the elongate opening72being engaged with the spindle71provided in the substrate50, the circular opening73being engaged with the operation pin27that extends from the rotor2. Also, the second sector65includes the circular opening67and the elongate opening68, the circular opening67being fit with the spindle66provided in the substrate50, the elongate opening68being engaged with the operation pin27that extends from the rotor2. These sectors60,65, and70respectively swing in trajectories, in accordance with the movement of the single operation pin27.

An arm portion26that extends in a radial direction is connected to the rotor axis21provided on the back side of the substrate50in the stepping motor1. The above-described operation pin27is connected to an end of the arm portion26, and extends to an opposite side of the shutter substrate50through an opening55provided in the shutter substrate50.FIG. 3Bshows a moving trajectory CR of the operation pin27, and corresponds toFIG. 2D. The operation pin27is capable of rotating at 360° according to the rotation of the rotor2. However, the opening55formed in the substrate50has a fan shape and a member29that regulates the movement of the arm portion26is provided. Therefore, in accordance with the present embodiment of the present invention, the operation pin27rotates within the given range RE.

The operation having the above-described configuration is described, with reference toFIG. 1,FIG. 4, andFIG. 5. These figures show changes in the positions of the first sector60, the second sector65, and the third sector70, when viewed from the front side of the shutter substrate50. On the upper sides of the figures, the stepping motor1is shown so that the rotation state of the rotor2can be confirmed.

FIG. 1shows the shutter opening51for image capturing provided in the substrate50in a fully open state. The rotor2in the stepping motor1has a rotation angle of 0°, yet is stopped on a slight tilt by the regulation member29(seeFIG. 3B). The detent torque causes the South magnetic pole and the North magnetic pole respectively to move to the positions that face the first magnetic pole11and the second magnetic pole12, yet they are retained in a state where they are regulated by the regulation member29. Accordingly, it is possible to retain this state without applying current to the coils4or5in the state shown inFIG. 1.

FIG. 4shows the shutter opening51for image capturing provided in the substrate50in a fully closed state.FIG. 4shows a state where the rotor2rotates clockwise from the state shown inFIG. 1, and the operation pin27rotates in conjunction with this rotation. The first sector60, the second sector65, and the third sector70swing in given trajectories, according to the rotation of the operation pin27, and then the shutter opening51is closed by the first sector60and the second sector65. At this time, the first sector60and the third sector70include the engagement openings having the above-described configuration, and therefore move in a rotational area having a width narrower than a simple circular motion.

FIG. 5is a view showing a small aperture state where the aperture blade is positioned in the shutter opening51for image capturing provided in the substrate50.FIG. 5shows the state where the rotor2further rotates in a clockwise direction from the state shown inFIG. 4. The operation pin27rotates in conjunction with this motion. The first sector60, the second sector65, and the third sector70swing in given trajectories in conjunction with the rotation of the operation pin27. The first sector60and the second sector65move away to the positions where the shutter opening51is opened. Instead, the third sector70moves to a position where the shutter opening51is closed. The third sector70includes the aperture opening75, and realizes the shutter opening51in a small aperture state. Also, at this time, the first sector60and the third sector70include the engagement openings having the above-described configuration, and moves in a rotational area having a width narrower than a simple circular motion.

Although a preferred embodiment has been described heretofore, the present invention is not limited to the above-mentioned embodiment, and other embodiments, variations and modifications may be made without departing from the scope of the present invention. In accordance with the above-described embodiment, the second sector has the conventional engagement openings. In this manner, the sector drive apparatus may employ the conventional sector together with the sector in which the configuration of the engagement openings has been changed to be driven efficiently. In addition, the sector drive apparatus may employ the sectors where the configurations of the engagement openings in all the sectors have been changed.