JP4077700B2 - Shutter device for digital camera - Google Patents

Description

[0001]
BACKGROUND 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 open and close in conjunction with a reciprocating rotation 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 an exposure time has elapsed after being set to a fully open state. Thereafter, the fully closed state is reset to the fully opened 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 the lens opening. In order to simultaneously open and close the plurality of shutter blades, an opening / 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 reciprocating the opening and closing member with a motor. In order to open / close the shutter blades via the opening / closing member, a single reciprocating motor is used. Some conventional digital cameras include aperture blades in addition to shutter blades. The diaphragm blades are also arranged to be openable and closable with respect to the lens opening. This diaphragm blade is also opened and closed on the same principle as the shutter blade.
[0003]
[Patent Document 1]
Japanese Utility Model Publication No. 3-29837 [Patent Document 2]
Japanese Utility Model Publication No. 3-108229 [Patent Document 3]
Japanese Utility Model Publication No. 1-116583.
[Problems to be solved by the invention]
In the above-described digital camera having an aperture function, at least two actuators have to be used for the motor that operates the shutter blades and the motor that operates the aperture blades. For this reason, in the shutter device for a low-price digital camera that occupies a large portion of the actuator cost, the number of actuators has a great influence on the manufacturing cost of the shutter device.
[0005]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a low-cost digital camera shutter device by reducing the number of motors by causing a shutter operation and a small aperture operation to be performed by a single actuator. . The following measures were taken in order to achieve this purpose. 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 to open and close the shutter blade. And a magnetized rotor that can be rotated in both directions between one end position and the other end position, and a magnetic holding force when the rotor is at one point, an intermediate position, and the other end position. A yoke disposed at a position where the rotor occurs, a coil that is wound around the yoke and rotates the rotor in response to energization, and a stopper, and the rotor is divided into four poles so as to be substantially equally divided in the circumferential direction. 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. Before In the yoke, the angle interval θ1 between the magnetic poles adjacent to each other is set in a range of 45 ° <θ1 <90 °, and the yoke has an angle width θ2 of the facing surface of each magnetic pole facing the rotor of θ2 <45 °. In the rotor, 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 <45 ° by the stopper, and the shutter blades Depending on the position of the three points of the rotor, it is possible to move to three points: a fully open position that opens the lens opening, a fully closed position that closes the lens opening, and a small aperture position that partially opens the lens opening. At the same time, the shutter blade can be held at one of the three points even when the power supply to the coil is cut off.
[0006]
Preferably, the shutter blade is placed in a fully open position corresponding to one end position of the rotor, placed in a small throttle position corresponding to the intermediate position of the rotor, and placed in a fully closed position corresponding to the other end position of the rotor. placed Ru.
[0007]
According to the present invention, the shutter blade is also used as the aperture blade. Only one electromagnetic actuator is used to cause the shutter blades to fully open, small aperture, and fully closed.
[0008]
DETAILED DESCRIPTION OF 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 a 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 composed of a cylindrical magnet magnetized with four poles, and can be rotated bidirectionally between one end position and the other end position with an intermediate position therebetween. (A) represents a state in which the rotor 11 is in an intermediate position. The yoke 12 is arranged at a position where a magnetic holding force is generated when the rotor is at three points, one end position, an intermediate position and the other end position. In the present embodiment, the yoke 12 has a substantially E shape having three magnetic poles 121, 122, 123 facing the rotor 11. The opposing surface 121F facing the rotor 11 of the first yoke 121 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, the facing surface 123F of the third magnetic pole 123 facing the rotor 11 is also a concave curved surface. The opposing surfaces 121F to 123F of these three magnetic poles 121 to 123 all have the same curvature and the same angular width. The coil 13 is wound around a magnetic pole 122 located in the middle of the three magnetic poles of the yoke 12 and reciprocates the rotor 11 in response to energization.
[0009]
In the state shown in (A), since the center position between the north and south poles of the rotor 11 magnetized with four poles 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. Note that an operating pin 11P is attached to the rotor 11 via an arm 11L. The operating pin 11P is inserted into a stopper hole 31 formed in the 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 positioned just in the middle of the rectangular stopper hole 31.
[0010]
When the coil 13 is energized in the state shown in (A), an N pole is generated in the central magnetic pole 122 of the yoke 12 as shown in (B), and the opposite S poles are formed on the two magnetic poles 121 and 123 on both sides. Will occur. Thereby, a rotational force is generated in the rotor 11 due to the interaction between the repulsion and the suction, and the counterclockwise rotation occurs. With this rotation, the operating pin 11P moves through the stopper hole 31 and comes into contact with one end to stop. As a result, the rotor 11 of the electromagnetic actuator 1 is rotated from the intermediate position to the one end position. After that, even if the coil 13 is turned off, the holding force is applied to the rotor 11 from the three magnetic poles of the yoke 12, and further the counterclockwise rotational force is applied. It 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 in the magnetic pole 122 at the center of the yoke 12 and the magnetic poles 121 on both sides are generated. , 123 generate N poles. As a result, a rotational force is generated in the rotor 11, and the rotor 11 rotates in the clockwise direction. When a long pulse, which will be described later, is applied here, the operation pin 11P rotates until it comes into contact with the other end of the stopper hole 31 to reach a stop state. The position of the rotor 11 is the other end position shown in FIG. After that, even if the coil 13 is de-energized, the holding force is applied between the rotor 11 and the three magnetic poles 121 to 123 of the yoke 12, and the rotor 11 is illustrated in a state where a clockwise rotational force is applied. Can be stationary at the other end position. The condition that the rotor 11 is stationary at the one end position shown in (B) and the other end position shown in (C) is when the rotation angle of the rotor 11 is less than ± 45 °.
[0012]
FIG. 2 is a schematic plan view showing a specific embodiment of the electromagnetic actuator shown in FIG. FIG. 2 shows a state in which the rotor is in an intermediate position. A straight line dividing the magnetic pole of the rotor 11 into four parts is represented by the X axis and the Y axis. A straight line passing through the center of the opposing 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 (1) is set to 25.75 °. The angular 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 magnetic pole 122 in the middle 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 formed between the straight line (1) and the X axis. In this embodiment, θ1 is set to 64.25 °. Here, in the yoke 12, the angular 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. In addition, the angular 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 angular width θ2 of the facing surfaces 121F, 122F, 123F of the magnetic poles 121, 122, 123 facing the rotor 11 is set in a range of θ2 <45 ° . When the yoke 12 satisfies the angle conditions related to the above θ1 and θ2, the non-energized holding (stationary) at the three-point position is possible.
[0013]
On the other hand, paying attention to 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 the present embodiment. Similarly, the rotation angle between the intermediate position and the other end position is also 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, there is a possibility that the non-energized holding at the intermediate position may not be realized, and, as will be described in detail later, the transition from one end position to the intermediate position, or the transition from the one end position to the other end position. It can be difficult to do.
[0014]
FIG. 3 is a schematic plan view showing a shutter device for a digital camera according to the present invention. As shown in (A), the shutter device for a digital camera is assembled using a substrate 3. The substrate 3 is formed with the stopper hole 31 and the lens opening 32 described above. The electromagnetic actuator 1 shown in FIGS. 1 and 2 is mounted on the front side of the substrate 3. At that time, the operation pin 11P attached to the rotor 11 passes through the stopper hole 31 from the front side to the back side of the substrate 3.
[0015]
A pair of shutter blades 2L and 2R are mounted on the back side of the substrate 3. The shutter blades 2L and 2R are attached so that the lens opening 32 formed in the substrate 3 can be opened and closed. Specifically, one shutter blade 2L is attached to be rotatable about a pin 21L planted on the substrate 3. The other shutter blade 2 </ b> R is also attached so as to be rotatable about a pin 21 </ b> R implanted in the substrate 3. One shutter blade 2L has a long hole 22L. Similarly, a long hole 22R is formed in the other shutter blade 2R. The operating pins 11P of the electromagnetic actuator 11 are 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 operating pin 11P are retracted from the lens opening 32 to the left and right, and are fully opened.
[0017]
Here, when a short pulse is applied to the coil 13, the rotor 11 rotates in the clockwise direction, 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 and 2R partially intervene in the lens opening 32 in conjunction with each other. As a result, the illustrated small aperture state 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 enters the state shown in (C). . At this time, the pair of shutter blades 2L and 2R operate in conjunction with the operation pin 11P to completely block the lens opening 32. Thereby, the fully closed state of the shutter device is obtained. As is clear from the above description, in order to temporarily shift from the fully open state of (A) to the small aperture state of (B), it is necessary to apply a short pulse to the coil. 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, with reference to FIG. 4, the exposure operation of the digital camera shutter device shown in FIG. 3 will be described. (A) represents a normal exposure operation for shifting from the fully open state to the fully closed state. In the digital camera, the shutter device is fully opened in the 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 40 ms, for example. By applying this long pulse to the coil, the shutter blade moves from the fully open position to the fully closed position, and one imaging operation is completed. Thereafter, even after the application of the pulse is canceled in the period T3, the shutter blades are not energized and are fully closed. Thereafter, by applying a pulse of reverse polarity, the shutter blades return from the fully closed state to the fully open state. This reset pulse is also a long pulse, and its width T4 is 40 ms, for example. Thereafter, even during the period T5 when the reset pulse is released, the shutter blade is not energized and is held at the fully open position, and enters a standby state for the next photographing operation.
[0020]
(B) represents a timing chart in the case of performing a photographing operation in a state where the lens aperture is a small stop. In the period T0, subject information is collected, and as a result, when it is determined that the aperture needs to be applied, a short pulse is applied, and the shutter blades are shifted from the fully open position to the small aperture position. The short pulse width TX is, for example, 5 to 10 ms. In this way, 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. When a predetermined exposure time T1 elapses after setting the small aperture state, a long pulse is applied to the coil, the shutter blades are shifted from the small aperture state to the fully closed state, and one photographing operation is completed. The time width T2 of the long pulse applied at this time is, for example, 30 ms. Thereafter, the fully closed state is maintained in the non-energized state in the period T3, and then a pulse having a reverse polarity is applied in the period T4 to reset the shutter blades from the fully closed position to the fully opened position.
[0021]
【The invention's effect】
As described above, according to the present invention, the shutter device for a digital camera performs a full opening operation and a full closing operation with a plurality of shutter blades, and also has a small aperture function. By driving such a shutter device for a digital camera with a single actuator, it is possible to perform a shutter blade fully closed operation, a fully open operation, and a small aperture diameter set / reset. Conventionally, two motors are required, but in the present invention, the number of motors can be reduced to one, and the manufacturing cost can be reduced by 30 to 40% compared to the conventional one.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing an electromagnetic actuator incorporated in a shutter device for a digital camera 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 shutter device for a digital camera according to the present invention.
4 is a timing chart for explaining the operation of the shutter device for the digital camera 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 opening

Claims (2)

A shutter blade that opens and closes the lens opening of the digital camera, and an electromagnetic actuator that is connected to the shutter blade and drives to open and close the shutter blade.
The electromagnetic actuator includes a magnetized rotor capable of bi-directionally rotating between one end position and the other end position across an intermediate position, and the rotor at three points: one end position, an intermediate position, and the other end position. A yoke disposed at a position where a magnetic holding force is generated at a certain time, a coil wound around the yoke and rotating the rotor in response to energization, and a stopper ;
The rotor is composed of magnets magnetized in four poles so as to be substantially equally divided in the circumferential direction, the yoke has a substantially E shape having three magnetic poles facing the rotor, and the coil is the three coils. Is wound around a magnetic pole located in the middle of
The yoke has an angular interval θ1 between adjacent magnetic poles set in a range of 45 ° <θ1 <90 °,
In the yoke, the angular width θ2 of the facing surface of each magnetic pole facing the rotor is set in a range of θ2 <45 °,
In the rotor, 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 <45 ° by the stopper,
The shutter blade moves to three points, a fully open position that opens the lens opening, a fully closed position that closes the lens opening, and a small aperture position that partially opens the lens opening, according to the positions of the three points of the rotor. A shutter device for a digital camera, which is capable of holding the shutter blade at one of the three points even when power to the coil is cut off .   The shutter blade is placed in a fully open position corresponding to one end position of the rotor, placed in a small aperture position corresponding to the intermediate position of the rotor, and placed in a fully closed position corresponding to the other end position of the rotor. The shutter device for a digital camera according to claim 1.

Images