JPH11194381A - Camera diaphragm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a small-sized, light-weight and durable diaphragm device capable of obtaining three kinds of completely circular apertures having improved diameter accuracy. SOLUTION: Blades 7 and 8 supported by a shaft 1b on a base plate 2 are held in an initial position by a torsion spring 9 so that the blades 7 and 8 may not interfere with an exposure aperture AP. The output pin 3f of a moving magnet is rotated in any direction in accordance with the coil energizing direction, and an intermediate lever 6 is rotated while enlarging the rotational angle of the pin 3f. And, either of blades 7 and 8 is operated in accordance with the rotating direction of the intermediate lever 6 so as to control the aperture diameter of the aperture AP. When the aperture is controlled by either blade, a bypass transistor is turned off, then, a current flowing in the coil is reduced, then, the power consumption is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm device for a camera using a moving magnet as a driving source, and more particularly to a diaphragm device for a camera capable of selecting three kinds of aperture values by switching the direction of current supply to the moving magnet.

[0002]

2. Description of the Related Art In recent years, so-called digital cameras have become widespread, and for digital cameras, the exposure tolerance of the image pickup means is very narrow. Therefore, an aperture device having a high aperture accuracy and an opening shape as close to a perfect circle as possible is desired. It is.

[0003]

As a diaphragm device capable of obtaining a true circular aperture diameter, there is known a diaphragm device in which a turret having a plurality of circular apertures formed on a disk is retracted to the center of the optical axis of a taking lens. However, this turret type requires a turret having a much larger outer dimension than the lens aperture, and thus has the disadvantage of increasing the size. Therefore, in order to eliminate this drawback, a plurality of aperture blades with different aperture diameters are provided, and the objective aperture blade is retracted with the galvanometer as the driving source while the other aperture blades are not displaced. Is known. However, when a galvanometer is used as the drive source, the coil to be energized becomes a movable member, which causes a problem in durability. In addition, the galvanometer requires a large amount of operation of the diaphragm blade compared to the amount of operation of the galvanometer. It is necessary to interpose a gear for double speed between the diaphragm blades and the aperture blade, which causes a problem that the required torque increases. The present invention has been made in view of such problems, and has as its object to provide a diaphragm apparatus for a camera that is small, lightweight, excellent in durability, and consumes little power.

[0004]

In summary, a diaphragm device for a camera according to claim 1 includes: a base plate (1) having a full opening opening (exposure aperture AP) for regulating a full opening diameter.
2) and: a middle aperture opening (8c) smaller than the full-opening opening formed in the main plate is formed. A first diaphragm blade (8) for further restricting an aperture diameter of which the diaphragm opening is regulated by the full aperture, and a small diaphragm smaller than a middle diaphragm opening formed in the first diaphragm blade; An opening (7c) is formed, retreats from the full opening at the initial position, and operates up to the forward limit to further restrict the opening diameter of the small aperture opening restricted by the full opening. With the second diaphragm blade (7):
An output pin (3f) is provided at a position eccentric from the center of rotation,
The output pin operates in both forward and reverse directions from the neutral position depending on the energizing direction, and the output pin operates in one direction to operate the first diaphragm blade from its initial position to the limit of forward movement, and the output pin operates in the other direction. A moving magnet (3) for actuating the second diaphragm blade from its initial position to its forward limit; and a current supply means (transistor Q1, which supplies a forward or reverse current to the moving magnet). Q2, Q3, Q4)
And: According to the first aspect, the current supply means switches the direction of the current supplied to the moving magnet so that the output pin of the moving magnet is operated in the forward or reverse direction from the neutral position, and the operation of the output pin is performed. Either of the first and second diaphragm blades is operated from the initial position toward the forward limit according to the direction, and the diameter of the opening formed by the full opening is regulated by the middle diaphragm opening or the small diaphragm opening. As a result, either a medium aperture or a small aperture can be obtained. Therefore, three types of aperture diameters can be obtained by controlling the direction of the drive current, including the state where both the aperture blades are at the initial position.

[0005] A camera diaphragm device according to claim 2 is as follows:
Assuming the above: The output pin of the moving magnet is stopped near the center of its movable range when no power is supplied. According to the second aspect of the present invention, it is easy to make the moving magnets substantially equal in operation amount regardless of the use of any of the aperture blades, and it becomes easy to adjust the motor torque and control the drive current.

A camera diaphragm device according to a third aspect of the present invention is:
Assuming the above: a center of rotation (1a) is provided at an intermediate portion between the center of rotation (3c, 3d) of the moving magnet and the output pin (3f). An intermediate lever (6) having an engagement pin (6b) formed on a side opposite to the center of rotation of the moving magnet when viewed from an engagement portion with the output pin. The first aperture blade and the second aperture blade are operated by an operation. In this case, since the rotation center of the intermediate lever is located between the rotation center of the moving magnet and the output pin of the moving magnet, the rotation angle of the intermediate lever becomes larger than the rotation angle of the moving magnet. When the aperture blade is operated by the engagement pin implanted in the intermediate lever, it is possible to easily obtain a turning angle sufficient to operate the aperture blade.

According to a fourth aspect of the present invention, based on the third aspect: a first stopper member (13) for regulating an initial position of the first aperture blade; Second stopper member (12) for regulating the initial position
And: a spring (9) for urging the first diaphragm blade and the second diaphragm blade in a direction of pressing against the respective stopper members, and: the first diaphragm blade is provided with the first stopper member. A predetermined clearance is formed in a contact portion (8a) between the engaging pin formed on the intermediate lever and the first diaphragm blade, and the second diaphragm blade is moved to the second diaphragm blade. In the state pressed against the second stopper member, a predetermined clearance is formed at a contact portion (7a) between the engagement pin formed on the intermediate lever and the second aperture blade. In this case, each aperture blade is pressed against each stopper member by a spring, and in this state, a clearance is formed between the engagement pin formed on the intermediate lever and each aperture blade. Each aperture blade can maintain a stable initial position in a state where power is not supplied to the moving magnet.

According to a fifth aspect of the present invention, there is provided a diaphragm device for a camera, based on the first, second, third or fourth aspect of the present invention:
The current supply means includes the first diaphragm blade and the second diaphragm blade.
Power switching means (R) for switching the power supplied to the moving magnet between the time when the first diaphragm blade is run and the time when the first diaphragm blade and the second diaphragm blade are held.
1, Q5). According to the fifth aspect, it is possible to reduce the power consumption while maintaining the target aperture value, which can contribute to a reduction in power consumption as a whole.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a plan view of a diaphragm device for a camera according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a blade drive mechanism. In the drawing, reference numeral 1 denotes an upper base plate, and 2 denotes a base plate, and an exposure aperture AP is opened at a central portion of both base plates 1 (2). Note that, in the plan view, the upper ground plate 1 is removed in order to represent the inside state. 3
Denotes a moving magnet, and a magnet 3b is rotatably mounted on the inside of a cylindrical case 3a by shafts 3c and 3d. A coil 3e is wound around the case 3a. When the coil 3e is energized, the magnet 3b rotates clockwise or counterclockwise in FIG. 1 within a predetermined angle range according to the energizing direction. An eccentric output pin 3f is formed on the side surface of the magnet 3b. still,
In the plan view, with respect to the moving magnet 3, only the magnet 3b and the output pin 3f are virtually shown by dashed lines. The case 3 a is fixed on the upper base plate 1 with screws 4 and 5.

Reference numeral 6 denotes an intermediate lever, which is a shaft 1a on the main plate 1.
It is supported swingably. An output pin 3f is engaged with a hole 6a formed near the center of the intermediate lever 6, and when the output pin 3f rotates about the shafts 3c and 3d,
The intermediate lever 6 rotates about the shaft 1a. However, shaft 1a
Is provided between the shafts 3c and 3d and the output pin 3f on the plane, the rotation angle of the intermediate lever 6 is larger than the rotation angle of the output pin 3f. An engagement pin 6 b is formed on the back side of the front end of the intermediate lever 6, and the engagement pin 6 b reaches the inside of the base plate 2.

Reference numeral 7 denotes a diaphragm blade for a small diaphragm, and 8 denotes a diaphragm blade for a middle diaphragm. Each blade is rotatably supported by a shaft 1b planted on the back surface of the upper base plate 1. Reference numeral 9 denotes a torsion spring. The torsion spring 9 is wound around the shaft 1b, and has a biasing force in a direction in which its tip portions 9a and 9b move away from each other. The tip 9a of the torsion blade 9 is engaged with the aperture blade 7 to give the aperture blade 7 a left-handed turning property, and the tip 9b
Engages with the aperture blade 8 to give the aperture blade 8 a right-handed turning property. Therefore, the diaphragm blade 7 rotates counterclockwise until it comes into contact with the stopper 10 and maintains a state where it does not interfere with the exposure aperture AP. Similarly, the diaphragm blade 8 rotates clockwise until it comes into contact with the stopper 11 and does not interfere with the exposure aperture AP. The state is maintained. The diaphragm blade 7 has a contact portion 7a that contacts the engaging pin 6b at the tip of the intermediate lever 6. When the intermediate lever 6 rotates clockwise from the state shown in FIG. While being pushed by the engagement pin 6b, the shaft turns clockwise around the shaft 1b until the contact portion 7b contacts the stopper 10. Similarly, the aperture blade 8 has a contact portion 8a that abuts the engagement pin 6b. When the intermediate lever 6 rotates leftward from the state shown in FIG. 1, the aperture blade 8 comes into contact with the engagement pin 6b. While being pushed, it rotates counterclockwise around the shaft 1b until the contact portion 8b contacts the stopper 11. In the initial state,
The engagement pin 6b at the end of the intermediate lever 6 has a slight clearance between the contact pin 7a on the diaphragm blade 7 side and a slight clearance between the contact pin 8 on the diaphragm blade 8 side. Has clearance. At this time, the aperture blades 7 and 8 are torsion springs 9
Are pressed against the stoppers 12 and 13 respectively. Further, a small aperture opening 7c is formed in the aperture blade 7, and the small aperture opening 7c becomes concentric with the exposure aperture AP when the aperture blade 7 is turned clockwise until regulated by the stopper 10. Similarly, the diaphragm blade 8 is formed with a middle diaphragm opening 8c, and the middle diaphragm opening 8c becomes concentric with the exposure opening AP when the diaphragm blade 8 turns clockwise until it is regulated by the stopper 11.

Next, FIG. 3 is a circuit diagram of the driver circuit, and 3e shows the above-mentioned coil. Q1 through Q
5 is a transistor, N1 and N2 are inverters,
R1 is a resistor, and 15 is a control device using an MPU or the like. A drive current is supplied to the coil 3e via a bridge circuit including a resistor R1 and transistors Q1 to Q4 in accordance with a combination of control signals O1 to O3 generated by the control device 15. First, since the transistor Q5 is for bypassing both ends of the resistor R1, it is assumed that the control signal O1 of the control device 15 is at the H level and the transistor Q5 is turned on. In this case, the transistors Q1 and Q2 are turned on, and a current flows through the coil 3e from left to right on the drawing. On the same assumption, when the control signal O3 is at the H level, the transistors Q3 and Q4 are turned on to turn on the coil 3e.
, A current flows from right to left on the drawing. Therefore, by switching the levels of the control signals O2 and O3, the direction of the current flowing through the coil 3e can be controlled, and thereby the rotation direction of the moving magnet 3 can be controlled. The transistor Q5 bypasses both ends of the voltage dividing resistor R1, and when the control signal O1 goes high and the transistor Q5 is turned on, the voltage applied to the coil 3e increases and the torque increases.

Next, the operation of the above embodiment will be described with reference to the above items and FIGS. First, in the initial state, the mechanism is in the state shown in FIG. When selecting the entire aperture diameter, the control device 15 controls all the control signals O1 to O3.
The shutter mechanism (not shown) is operated in a state where is maintained at the L level. When all the control signals O1 to O3 are at the L level, all the transistors Q1 to Q5 are turned off, so that no current is supplied to the coil 3e, and the output pin 3f of the moving magnet 3 maintains the state shown in FIG. Therefore, the intermediate lever 6 also maintains the state shown in FIG.
Keeps being pressed against the stoppers 12 and 13 by the urging force of the torsion spring 9. Accordingly, the aperture of the exposure aperture AP is not restricted by the aperture blades 7 or 8. When the shutter opening / closing mechanism (not shown) is operated in this state, full-open photographing is performed.

Next, the operation in the case of the middle aperture photographing will be described. When performing medium-diameter shooting, the control device 15 sets the control signals O1 and O2 to the H level and maintains the control signal O3 at the L level. When the control signal O1 goes high, the transistor Q5 is turned on, and both ends of the resistor R1 are bypassed via the transistor Q5. When the control signal O2 goes high, the transistors Q1 and Q2 are turned on, and the coil 3e has a resistor R1 and transistors Q1 and Q2.
3, a current flows from left to right in FIG.
The output pin 3e of the moving magnet 3 rotates counterclockwise from the state shown in FIG. When the voltage between the collector and the emitter of each of the conducting transistors is considered to be at a sufficiently low level, the power supply voltage is substantially applied to the coil 3e. Will rotate counterclockwise.

When the output pin 3e rotates by a predetermined angle, the intermediate lever 6 rotates counterclockwise by an angle larger than the rotation angle of the intermediate lever 6 while the hole 6a is engaged with the output pin 3f. When the intermediate lever 6 rotates counterclockwise, the engaging pin 6b at the tip of the intermediate lever 6 pushes the diaphragm blade 8 against the biasing force of the torsion spring 9 while engaging the contact portion 8a. The rotation of the diaphragm blade 8 in the counterclockwise direction is stopped at a position where the contact portion 8b contacts the stopper 11 as shown in FIG. Therefore, the exposure aperture AP is regulated by the middle aperture opening 8c formed in the aperture blade 8. Aperture blade 8
After a lapse of time sufficient to rotate the transistor Q to the position shown in FIG. 4, the control device 15 sets the control signal O1 to the L level to turn off the transistor Q5. Therefore, since the combined resistance between the power supply and the ground increases, the value of the current supplied to the coil 3e decreases, and the power consumption is reduced. At this time, the holding force of the magnet decreases with a decrease in the current value, but the holding force is sufficient to withstand the returning torque of the moving magnet to the initial position and the urging force of the torsion spring 9. If the resistance value of the resistor R1 is selected so as to obtain the following, the power consumption can be reduced while maintaining the aperture value.

After the middle aperture photographing is performed by operating a shutter opening / closing mechanism (not shown), when the control device 15 sets the control signal O2 to the L level, all the transistors are turned off, so that no current flows through the coil 3e. The output pin 3f of the moving magnet 3 rotates clockwise by the initial position return torque and returns to the initial position, and the diaphragm blade 8 rotates clockwise by the urging force of the torsion spring 9 to contact the stopper 13. Stop.

Next, the operation in the case of the small aperture photographing will be described. When performing small-diameter imaging, the control device 15 sets the control signals O1 and O3 to H level and maintains the control signal O2 to L level. When the control signal O1 goes high, the transistor Q5 is turned on, and both ends of the resistor R1 are bypassed via the transistor Q5. When the control signal O3 goes high, the transistors Q3 and Q4 are turned on, and the coil 3e has a resistor R1 and transistors Q3 and Q4.
3, a current flows from right to left in FIG.
The output pin 3e of the moving magnet 3 rotates clockwise from the state shown in FIG.

When the output pin 3e rotates by a predetermined angle, the intermediate lever 6 rotates clockwise by an angle larger than the rotation angle of the intermediate lever 6 while the hole 6a is engaged with the output pin 3f. When the intermediate lever 6 rotates clockwise, the engaging pin 6 at the tip of the intermediate lever 6 is rotated.
b rotates the diaphragm blade 7 clockwise about the shaft 1b against the urging force of the torsion spring 9 while engaging the contact portion 7a thereof, and rotating the diaphragm blade 7 clockwise in FIG. As shown in (5), it stops at the position where the contact portion 7b contacts the stopper 10. Therefore, the exposure aperture AP is regulated by the small aperture aperture 7c formed in the aperture blade 7. After a lapse of time sufficient to rotate the aperture blade 7 to the position shown in FIG. 5, the control device 15 sets the control signal O1 to L level to turn off the transistor Q5, thereby reducing power consumption. After the small aperture photographing is performed by activating the shutter opening / closing mechanism (not shown), when the control device 15 sets the control signal O3 to the L level, all the transistors are turned off, so that no current flows through the coil 3e and the moving magnet 3
The output pin 3f rotates counterclockwise by the initial position return torque and returns to the initial position, and the diaphragm blade 7 rotates counterclockwise by the urging force of the torsion spring 9 to contact the stopper 12 and stop. .

[0019]

As described above, according to the present invention, it is possible to obtain a diaphragm device which can obtain three kinds of apertures which are small and lightweight while having a perfect circular shape and aperture precision, and can obtain a movable member. Since no energizing operation is performed on the battery, there is no trouble such as disconnection due to aging, and sufficient durability can be obtained. Further, according to the second aspect of the invention, it is easy to make the moving amounts of the moving magnets substantially equal regardless of the use of any one of the aperture blades, so that the adjustment of the motor torque and the control of the drive current become easy. According to the third aspect of the present invention, the rotation angle is enlarged when the rotation operation of the moving magnet is converted into the rotation operation of the intermediate lever. Therefore, even if the rotation amount of the moving magnet is small, a rotation angle sufficient for practical use can be easily obtained. It is possible to obtain. In the case of the fourth aspect, each aperture blade is pressed against each stopper member by a spring, and in this state, a clearance is formed between an engagement pin formed on the intermediate lever and each aperture blade. Therefore, each aperture blade can maintain a stable initial position in a state where power is not supplied to the moving magnet. Further, according to the fifth aspect, it is possible to reduce the power consumption while maintaining the target aperture value, which can contribute to the reduction of the power consumption as a whole.

[Brief description of the drawings]

FIG. 1 is a plan view of an aperture device for a camera according to an embodiment of the present invention in an initial state.

FIG. 2 is a cross-sectional view of a blade driving mechanism portion of the camera diaphragm device shown in FIG.

FIG. 3 is a circuit diagram showing an example of a drive circuit of the camera diaphragm device according to the embodiment of the present invention.

FIG. 4 is a plan view showing the operation of the camera diaphragm device shown in FIG. 1 in a middle diaphragm state;

FIG. 5 is a plan view of the camera aperture device shown in FIG. 1 operated in a small aperture state;

[Explanation of symbols]

 Reference Signs List 1 upper base plate 1a rotating shaft of intermediate lever 6 2 base plate 3 moving magnet 3c, 3d rotating shaft of output pin 3f 3e coil 3f output pin 6 intermediate lever 6b engaging pin 7 aperture blade 7a, 7b contact portion 8 aperture blade 8a , 8b Contact part 9 Torsion spring 15 Controller Q1, Q2, Q3, Q4, Q5 Transistor N1, N2 Inverter R1 Resistance

Claims (5)

[Claims] 1. A base plate having a full-opening opening for regulating the full-opening diameter, and a middle-diaphragm opening smaller than the full-opening opening formed on the base plate, wherein the full-opening opening is formed at an initial position. The middle aperture opening is formed on the first aperture blade which further retreats from the portion and operates to the forward limit to further regulate the opening diameter regulated by the full opening aperture, and the first aperture blade. A small aperture opening smaller than the middle aperture opening is formed. At the initial position, the small aperture opening is retracted from the full aperture opening and operates to the forward limit so that the small aperture opening is closed by the full aperture opening. A second diaphragm blade for further regulating the aperture diameter to be regulated, and an output pin at a position eccentric from the center of rotation, wherein the output pin operates in both forward and reverse directions from a neutral position depending on the direction of energization; Act on one side A moving magnet for actuating the first diaphragm blade from its initial position to its forward limit and operating the second aperture blade from its initial position to its forward limit by operating the output pin to the other end; And a current supply means for supplying a current in a forward direction or a reverse direction to the camera. 2. An aperture device for a camera according to claim 1, wherein said output pin of said moving magnet stops near a middle point of its movable range when no power is supplied. 3. A diaphragm device for a camera according to claim 1, wherein said rotation pin has a rotation center at an intermediate portion between the rotation center of said moving magnet and said output pin, and is rotated by being engaged with said output pin. And an intermediate lever having an engaging pin formed on a side opposite to the center of rotation of the moving magnet when viewed from an engaging portion with the output pin, and actuated by the engaging pin formed on the intermediate lever. An aperture device for a camera, wherein the first aperture blade and the second aperture blade are operated. 4. A diaphragm device for a camera according to claim 3, wherein said first stopper member regulates an initial position of said first diaphragm blade, and a second stopper member regulates an initial position of said second diaphragm blade. A stopper member, and a spring for urging the first diaphragm blade and the second diaphragm blade in a direction of pressing against the respective stopper members, and the first diaphragm blade is provided on the first stopper member. In the pressed state, the engagement pin formed on the intermediate lever and the first pin
A predetermined clearance is formed at a contact portion with the diaphragm blade of the second, and an engagement pin formed on the intermediate lever and the second pin are pressed when the second diaphragm blade is pressed against the second stopper member. 2. A diaphragm device for a camera, wherein a predetermined clearance is formed in a contact portion with the second diaphragm blade. 5. A diaphragm apparatus for a camera according to claim 1, wherein said current supply means causes said first diaphragm blade and said second diaphragm blade to travel. An aperture device for a camera, comprising: power switching means for switching power supplied to the moving magnet at a time and when the first aperture blade and the second aperture blade are held.