JP2004109933A - Shutter device for digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive shutter device for digital cameras in which the number of motors is reduced by performing shutter operation and minimum aperture operation with one actuator. <P>SOLUTION: The shutter device for a digital camera is composed of shutter blades 2L, 2R arranged on a substrate 3 on which a lens aperture 32 is formed and an electromagnetic actuator 1 which is connected to the blades for driving their opening/closing. The electromagnetic actuator 1 is equipped with a rotor 11 which is rotatable in both directions between one end position and the other with an intermediate position held in-between, a yoke 12 arranged at a position where a magnetic coercive force is generated when the rotor 11 is at the three positions of the one, the intermediate and the other, and a coil 13 which is wound on the yoke 12 to rotate the rotor 11 on energization. The shutter blades 2L, 2R, concurrently with the three points of the rotor 11, are movable to three points, namely, a fully opened position (A) for opening the lens aperture 32, a fully closed position (C) for closing it, and a minimum aperture position (B) for partly opening it. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a shutter device for a digital camera of a type generally called a lens shutter. More specifically, the present invention relates to a shutter device for a digital camera in which a plurality of shutter blades perform an opening / closing operation in conjunction with a reciprocating rotation operation of a motor and have a small aperture function.
[0002]
[Prior art]
The digital camera is provided with a lens shutter, and performs a single photographing operation by shifting to a fully closed state after a lapse of exposure time after being set to a fully open state. Thereafter, the fully closed state is reset to the fully open state in preparation for the next photographing. Such a shutter device for a digital camera is arranged on a shutter substrate so that a plurality of shutter blades can open and close a lens opening. In order to simultaneously open and close a plurality of shutter blades, an opening and closing member having an operating pin is used. A long hole formed in each shutter blade is engaged with an operating pin of the opening / closing member. The shutter blades are opened and closed by reciprocatingly driving the opening and closing members with a motor. A single reciprocating motor is used to open and close the shutter blades via an opening and closing member. Some conventional digital cameras include an aperture blade in addition to a shutter blade. The aperture blade is also arranged to be openable and closable with respect to the lens aperture. The aperture blade is also opened and closed according to the same principle as the shutter blade.
[0003]
[Patent Document 1]
Japanese Utility Model Laid-Open No. 3-29837 [Patent Document 2]
Japanese Utility Model Laid-Open No. 3-108229 [Patent Document 3]
Published Japanese Utility Model Application No. 1-116583
[Problems to be solved by the invention]
In a digital camera having the above-described aperture function, at least two actuators must be used for a motor for operating the shutter blades and a motor for operating the aperture blades. For this reason, in a low-priced digital camera shutter device in which the cost of the actuator occupies a large part, the number of actuators has a great influence on the manufacturing cost of the shutter device.
[0005]
[Means for Solving the Problems]
In view of the above-mentioned problems of the conventional technology, an object of the present invention is to provide a low-cost digital camera shutter device by reducing the number of motors by performing a shutter operation and a small aperture operation with one actuator. . The following measures have been taken to achieve this objective. That is, a shutter device for a digital camera according to the present invention includes a shutter blade that opens and closes a lens opening of a digital camera, and an electromagnetic actuator that is connected to the shutter blade and drives the shutter blade to open and close the shutter blade. A magnetized rotor rotatable bidirectionally between one end position and the other end position, and a magnetic holding force when the rotor is at three points of one end position, intermediate position and the other end position And a coil wound around the yoke and rotating the rotor in response to energization.The shutter blades are arranged in accordance with three positions of the rotor. It is possible to shift to three points: a fully open position for opening the lens opening, a fully closed position for closing the lens opening, and a small stop position for partially opening the lens opening.
[0006]
Preferably, the shutter blade is located at a fully open position corresponding to one end position of the rotor, is located at a small aperture position corresponding to an intermediate position of the rotor, and is at a fully closed position corresponding to the other end position of the rotor. Is placed. Further, the rotor is magnetized to four poles, the yoke has a substantially E-shape having three magnetic poles facing the rotor, and the coil is a magnetic pole located in the middle of the three magnetic poles. It is wound around. In this case, in the yoke, the angle interval θ1 between the magnetic poles adjacent to each other is set in a range of 45 ° <θ1 <90 °. In the yoke, the angle width θ2 of the opposing surface of each magnetic pole opposing the rotor is set in a range of 0 ° <θ2 <45 °. Further, the rotation angle θ3 between each of the one end position and the other end position and the intermediate position is set in a range of θ3 <θ1-45 °.
According to the present invention, the shutter blade is also used as the diaphragm blade. The shutter blades can be fully opened, small-apertured, and fully closed by only one electromagnetic actuator.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic plan view showing an electromagnetic actuator which is a main component of the shutter device for a digital camera according to the present invention. As shown in FIG. 1A, the electromagnetic actuator 1 basically includes a rotor 11, a yoke 12, and a coil 13. The rotor 11 is formed of a quadrupole magnetized cylindrical magnet, and is rotatable bidirectionally between one end position and the other end position with the intermediate position interposed therebetween. (A) shows a state where the rotor 11 is at the intermediate position. The yoke 12 is disposed at a position where a magnetic holding force is generated when the rotor is located at one of three positions, one end position, an intermediate position and the other end position. In this embodiment, the yoke 12 has a substantially E-shape having three magnetic poles 121, 122, 123 facing the rotor 11. The facing surface 121F of the first yoke 121 facing the rotor 11 is a concave curved surface. Similarly, the opposing surface 122F of the second magnetic pole 122 facing the rotor 11 is also processed into a concave curved surface. Similarly, a facing surface 123F of the third magnetic pole 123 facing the rotor 11 is also a concave curved surface. Each of the facing surfaces 121F to 123F of the three magnetic poles 121 to 123 has the same curvature and the same angular width. The coil 13 is wound around a magnetic pole 122 located at an intermediate position among the three magnetic poles of the yoke 12, and reciprocates the rotor 11 in response to energization.
[0009]
In the state shown in (A), the center position between the N-pole and the S-pole of the four-pole magnetized rotor 11 coincides with the center line of the magnetic pole 122 located in the middle. The magnetized magnet and the three magnetic poles of the yoke 12 are magnetically balanced, and the rotor 11 is held at an intermediate position in a non-energized state. An operating pin 11P is attached to the rotor 11 via an arm 11L. The operation pin 11P is inserted into a stopper hole 31 formed in a substrate on which the electromagnetic actuator 1 is mounted. In other words, the operating pin 11P passes through the stopper hole 31 from the front side to the back side of the board on which the electromagnetic actuator 1 is mounted. In the intermediate position shown in (A), the operating pin 11P is located exactly in the middle of the stopper hole 31 having a rectangular shape.
[0010]
When the coil 13 is energized in the state shown in (A), an N pole is generated in the center magnetic pole 122 of the yoke 12 as shown in (B), and the opposite S poles are formed in the two magnetic poles 121 and 123 on both sides. Occurs. As a result, a rotational force is generated in the rotor 11 by the interaction between the repulsion and the suction, and the rotor 11 rotates counterclockwise. With this rotation, the operating pin 11P moves through the stopper hole 31 and comes into contact with one end thereof and stops. Thus, the rotor 11 of the electromagnetic actuator 1 has rotated from the intermediate position to the one end position. After that, even if the energization of the coil 13 is cut off, the holding state is exerted on the rotor 11 from the three magnetic poles of the yoke 12, and the stop state shown in the drawing is continued in the state where the counterclockwise rotational force is applied. Can be maintained.
[0011]
On the other hand, when the coil 13 is energized in the reverse direction from the intermediate state shown in (A) or the state stopped at one end shown in (B), an S pole is generated at the center magnetic pole 122 of the yoke 12 and the magnetic poles 121 on both sides are formed. , 123 have N poles. As a result, a rotational force is generated in the rotor 11, and the rotor 11 rotates clockwise. Here, when a long pulse described later is applied, the operation pin 11P rotates until it comes into contact with the other end of the stopper hole 31 and reaches a stop state. The position of the rotor 11 is the other end position shown in FIG. After that, even if the energization to the coil 13 is cut off, the rotor 11 is shown in a state where a holding force acts between the three magnetic poles 121 to 123 of the yoke 12 and further a clockwise rotating force acts. Can be stopped at the other end position. Note that the condition in which the rotor 11 stops at the one end position shown in (B) and the other end position shown in (C) is a case where the rotation angle of the rotor 11 is ± 45 ° or less.
[0012]
FIG. 2 is a schematic plan view showing a specific example of the electromagnetic actuator shown in FIG. FIG. 2 shows a state where the rotor is at the intermediate position. A straight line dividing the magnetic pole of the rotor 11 into four parts is represented by an X axis and a Y axis. A straight line passing through the center of the facing surface 121F of the first magnetic pole 121 of the yoke 12 is represented by (1). A straight line passing through the center of the N pole of the rotor 11 on the yoke 12 side is represented by (2). In this embodiment, the angle from the Y axis to the straight line {circle around (1)} is set to 25.75 °. The angle interval between the straight line (1) and the straight line (2) is set to 19.25 °. A straight line passing through the center of the opposing surface 122F of the intermediate magnetic pole 122 of the yoke 12 coincides with the X axis. The angular interval between the first magnetic pole 121 and the second magnetic pole 122 is represented by an angle θ1 between the straight line (1) and the X axis. In this embodiment, θ1 is set to 64.25 °. Here, in the yoke 12, the angle interval θ1 between the magnetic poles 121 and 122 adjacent to each other is set in a range of 45 ° <θ1 <90 °. The same applies to the angular interval θ1 between the second magnetic pole 122 and the third magnetic pole 123. Further, the angle width θ2 of the facing surface 121F of the first magnetic pole 121 is set to 26.5 ° in this embodiment. In the yoke 12, the angle width θ2 of the opposing surfaces 121F, 122F, 123F of the magnetic poles 121, 122, 123 opposing the rotor 11 is set in a range of 0 ° <θ2 <45 °. When the yoke 12 satisfies the above angle conditions regarding θ1 and θ2, non-energized holding (stationary) at three points can be performed.
[0013]
On the other hand, focusing on the rotation angle of the rotor 11, the rotation angle θ3 between the one end position and the intermediate position is set to 17.5 ° in this embodiment. Similarly, the rotation angle between the intermediate position and the other end position is set to 17.5 °. Further, the rotation angle θ3 is set in a range of θ3 <θ1-45 °. If θ3 does not satisfy this condition, non-energization holding at the intermediate position may not be realized, and as described later in detail, the transition from one end position to the intermediate position, or the transition from one end position to the other end position is performed. Can be difficult to do.
[0014]
FIG. 3 is a schematic plan view showing a digital camera shutter device according to the present invention. As shown in FIG. 1A, the shutter device for a digital camera is assembled using a substrate 3. The above-mentioned stopper hole 31 and lens opening 32 are formed in the substrate 3. On the front side of the substrate 3, the electromagnetic actuator 1 shown in FIGS. 1 and 2 is mounted. At this time, the operating pin 11P attached to the rotor 11 penetrates from the front side to the back side of the substrate 3 via the stopper hole 31.
[0015]
On the back side of the substrate 3, a pair of shutter blades 2L and 2R are mounted. The shutter blades 2L and 2R are attached so as to open and close a lens opening 32 formed in the substrate 3. Specifically, one shutter blade 2L is attached to be rotatable about a pin 21L planted on the substrate 3. The other shutter blade 2R is also mounted to be rotatable about a pin 21R planted on the substrate 3 as well. A long hole 22L is formed in one shutter blade 2L. Similarly, a long hole 22R is formed in the other shutter blade 2R. An operating pin 11P of the electromagnetic actuator 11 is engaged with the long holes 22L and 22R.
[0016]
In the state shown in (A), the electromagnetic actuator 11 is stationary at one end position. The operating pin 11P is in contact with the lower side of the rectangular stopper hole 31. At this time, the pair of shutter blades 2L and 2R interlocking with the operation pin 11P are respectively retracted to the left and right from the lens opening 32, and are fully open.
[0017]
Here, when a short pulse is applied to the coil 13, the rotor 11 rotates clockwise and shifts from one end position to an intermediate position as shown in FIG. In this state, the rotor 11 is held without current by the holding force of the yoke 12. When the operating pin 11P moves from the one end position to the intermediate position, the shutter blades 2L, 2R interlock and partially intervene in the lens opening 32. As a result, the small aperture state shown is obtained.
[0018]
When a long pulse is applied from the fully open state shown in (A) or the small aperture state shown in (B), the rotor 11 shifts from one end position or intermediate position to the other end position, and becomes the state shown in (C). . At this time, the pair of shutter blades 2 </ b> L and 2 </ b> R operate in conjunction with the operation pin 11 </ b> P to completely block the lens opening 32. Thereby, the fully closed state of the shutter device is obtained. As is apparent from the above description, it is necessary to apply a short pulse to the coil in order to temporarily shift from the fully opened state (A) to the small aperture state (B). On the other hand, when shifting from the fully open state of (A) to the fully closed state of (C), a long pulse may be applied to the coil.
[0019]
Finally, the exposure operation of the digital camera shutter device shown in FIG. 3 will be described with reference to FIG. (A) shows a normal exposure operation for shifting from a fully open state to a fully closed state. In a digital camera, the shutter device is fully opened in an initial state. Here, when the release button is pressed and a predetermined exposure time period T1 elapses, a long pulse is applied. The pulse width T2 is set to, for example, 40 ms. By applying this long pulse to the coil, the shutter blade shifts from the fully open position to the fully closed position, and one photographing operation is completed. Thereafter, even after the application of the pulse is canceled in the period T3, the shutter blade is kept in a fully closed state without energization. Thereafter, by applying a pulse of the opposite polarity, the shutter blade returns from the fully closed state to the fully opened state. This reset pulse is also a long pulse, and its width T4 is, for example, 40 ms. Thereafter, even during the period T5 in which the reset pulse is released, the shutter blade is kept at the fully open position without power supply, and enters a standby state for the next photographing operation.
[0020]
(B) shows a timing chart when a photographing operation is performed with the lens aperture set to a small aperture. In a period T0, subject information is collected, and as a result, when it is determined that an aperture needs to be applied, a short pulse is applied to shift the shutter blade from the fully open position to the small aperture position. The width TX of the short pulse is, for example, 5 to 10 ms. In this manner, the next small aperture position or the fully closed position is selected by selecting the time width of the pulse to be applied from the fully open state. After a predetermined exposure time T1 has elapsed after the small aperture state has been set, a long pulse is applied to the coil, the shutter blades shift from the small aperture state to the fully closed state, and one shooting operation ends. The time width T2 of the long pulse applied at this time is, for example, 30 ms. After that, in the period T3, the fully closed state is kept in the non-energized state, and then in the period T4, a pulse of the opposite polarity is applied to reset the shutter blade from the fully closed position to the fully open position.
[0021]
【The invention's effect】
As described above, according to the present invention, the shutter device for a digital camera performs the full opening operation and the full closing operation with a plurality of shutter blades, and also has a small aperture function. By driving such a digital camera shutter device with one actuator, it is possible to perform a full closing operation, a full opening operation of the shutter blades, and set / reset of a small aperture diameter. While two motors are conventionally required, the present invention can reduce the number of motors to one, and can reduce the manufacturing cost by 30 to 40% as compared with the related art.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing an electromagnetic actuator incorporated in a digital camera shutter device according to the present invention.
FIG. 2 is a plan view showing a specific configuration example of the electromagnetic actuator shown in FIG.
FIG. 3 is a schematic plan view showing a digital camera shutter device according to the present invention.
FIG. 4 is a timing chart for explaining the operation of the digital camera shutter device shown in FIG. 3;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electromagnetic actuator, 2L ... Shutter blade, 2R ... Shutter blade, 3 ... Substrate, 11 ... Rotor, 12 ... Yoke, 13 ... Coil, 31 ... Stopper Hole, 32 ... lens aperture

Claims (6)

A shutter blade for opening and closing the lens opening of the digital camera, and an electromagnetic actuator connected to the shutter blade for driving the shutter blade to open and close,
The electromagnetic actuator has a magnetized rotor rotatable bidirectionally between one end position and the other end position across the intermediate position, and the rotor has three positions of one end position, the intermediate position and the other end position. A yoke arranged at a position where a magnetic holding force is generated at one time, and a coil wound around the yoke and rotating the rotor in accordance with energization,
The shutter blade shifts to three points of a fully open position for opening the lens opening, a fully closed position for closing the lens opening, and a small aperture position for partially opening the lens opening, according to three positions of the rotor. A shutter device for a digital camera, characterized in that it is possible. The shutter blade is located at a fully open position corresponding to one end position of the rotor, is located at a small aperture position corresponding to an intermediate position of the rotor, and is located at a fully closed position corresponding to the other end position of the rotor. The shutter device for a digital camera according to claim 1, wherein: The rotor is magnetized to four poles, the yoke has a substantially E-shape having three magnetic poles facing the rotor, and the coil is wound around a magnetic pole located in the middle of the three magnetic poles. 2. The shutter device for a digital camera according to claim 1, wherein the shutter device is rotated. 4. The shutter device for a digital camera according to claim 3, wherein the yoke has an angle interval θ1 between magnetic poles adjacent to each other set in a range of 45 ° <θ1 <90 °. 5. 4. The shutter device for a digital camera according to claim 3, wherein the yoke has an angle width [theta] 2 of an opposing surface of each magnetic pole opposing the rotor set in a range of 0 [deg. 5. The digital camera according to claim 4, wherein a rotation angle θ3 between each of the one end position and the other end position and the intermediate position is set in a range of θ3 <θ1−45 °. 6. Shutter device.

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