JPS6151778B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetically driven shutter that opens and closes shutter blades using electromagnetic force, and more particularly to an electromagnetically driven shutter for a camera that enables low power driving.

In general, many shutters used in cameras and the like utilize the restoring force of a pre-charged spring as their drive source. On the other hand, with the electronicization of cameras, cameras that use an electromagnetic device as a drive source for the shutter have recently come into use. This electromagnetic drive shutter has fewer parts and eliminates the need for a spring charge mechanism.
It has advantages over conventional spring-charged shutters, such as lower manufacturing costs.

However, because the driving force of electromagnetic shutters is weak, a large current must be passed through the coil in order to obtain the necessary driving force for the shutter, which is extremely inconvenient for cameras that only have small capacity batteries. .

The present invention has been made in view of the above circumstances, and includes blades that control the amount of light in the photographing optical path, a rotor that rotates to drive the blades, and The rotor has a conductor arranged in a wave shape around the rotor, and a magnetic circuit that applies a magnetic field in a predetermined direction to the conductor, and the rotor has a plurality of cutouts along the wave pattern of the conductor. The object of the present invention is to provide an electromagnetic drive shutter that is light in weight and that can efficiently connect electromagnetic force to the operation of the shutter, thereby enabling drive with low electric power.

The present invention will be explained in detail below with reference to the drawings. Fig. 1 is a perspective view showing an embodiment of the electromagnetically driven aperture shutter according to the present invention, Fig. 2 is an exploded perspective view of the shutter shown in Fig. 1, Fig. 2a is a maximum diameter regulating plate, Fig. 2b is 2c shows the sector ring and sector pin, and FIG. 2d shows the lower yoke, outer casing, and magnet. FIG. 3 is a plan view showing an example of the wire ring pattern printed on the movable part substrate shown in the second figure, and FIG. 4 is a partial perspective view showing the relationship between the magnets arranged in the fixed part and the movable part conductor pattern. It is. The same parts in the above figures are designated by the same reference numerals. In the figure, reference numeral 1 denotes a spring connection wire made of an elastic conductor, such as a phosphor bronze plate, and one end of which is connected to an insulating sheet 3.
It is bonded to the outer casing 2 of the shutter, which forms part of the fixed part yoke, through the yoke, and the other end is fixed to a terminal of a movable part wire pattern, which will be described later. This spring 1
are arranged in pairs at opposite positions on the periphery, and urge the sector ring of the movable part in the shutter closing direction. Reference numeral 2 denotes a yoke made of a soft magnetic material that forms the outer casing of the shutter and constitutes a magnetic path of the stator. Reference numeral 7 denotes the upper substrate of the yoke made of the same soft magnetic material as 2, and a small hole 7a is provided on its surface so that light, a mechanical part, or a shaft can pass therethrough. The small holes 7a are arranged at appropriate positions on the disk surface of the substrate 7. There is a hole 7 in the center of the board that forms a photographing optical path.
b is provided. Numeral 6 in Fig. 2d is a magnet, which is a small and powerful rare earth permanent magnet, and is arranged on the inner surface of the lower substrate 7' so that adjacent magnets have opposite polarities as shown in Fig. 4. There is.
Upper yoke substrate 7 facing the magnetic surfaces of these magnets
Similarly, magnets 6 are disposed on the inner surface of the magnet 6, and the polarities of these magnets are opposite to each other so that the magnetic flux is concentrated between the upper and lower magnetic poles. Reference numeral 4 in FIG. 2c denotes a sector ring of the movable part, which is made of a non-magnetic metal or plastic plate, and wire ring print patterns as shown in FIG. 3 are arranged on its front and back surfaces. The inner diameter part of 4 is provided with a protrusion 4a for fitting into the outer peripheral surface of the fixed part cylinder, and several sector pins 8 are fixed at equal angles on the circumferential part of 4 by crimping or soldering. has been done. An example of the wire ring print pattern 5 on the top 4 is shown in FIG. 3, where it undulates in a concave and convex shape and goes around the circumference alternately along the radial and circumferential directions, and moves to the back side at the point 5c. Again, it is composed of a single conductor pattern with a pattern similar to that on the surface. In addition, the movable part 4 is provided with a plurality of notches 4b along the wire ring print pattern 5 to reduce the weight of the movable part 4 and to be used as a contact part of a stopper or an optical path.
When an unreasonable force is applied to the movable part 4, the movable part 4 is elastically deformed and can absorb this.

Reference numeral 7 in FIG. 2b is an upper yoke substrate, in which escape grooves 7c for the sector pins 8 are arranged at several places, and the same number of holes 7a for passing light or shafts are arranged as shown in the figure, and the shutter blades 9, The shaft pins 11 forming the rotation axis of the aperture blades 10 which also serve as shutter blades are fixed by crimping the same number of pins. This yoke substrate 7 can also be formed integrally by sintering or the like. The center hole 7b of the substrate 7 is a photographing optical path. Also small hole 7
d is a mounting hole for attaching the shutter to the camera. Reference numeral 8 in FIG. 2c is a sector pin which serves to transmit the rotation of the sector ring 4, which is a movable part, to the shutter blade 9 or the dual-purpose blade 10. This is made of non-magnetic metal (phosphor bronze, etc.) and is fixed to the movable part 4. The shutter blade 9, a part of which is shown in FIG. 2b, is rotatable around the shaft pin 11, and controls exposure by opening and closing the opening 12a on the maximum aperture regulating plate 12 shown in FIG. 2a. At the same time, when the brightness of the subject is high, it opens halfway and doubles as an aperture blade. The shutter blades are made from extremely lightweight sheets of plastic or titanium. A shutter blade 9 and a dual-purpose blade 1 that engage with a sector pin 8 fixedly planted in the movable part 4
The holes 9a and 10a are both elongated holes, and are designed to absorb the difference between the radius of rotation of the sector pin 8 and the radius of rotation of the hole, so that the rotation of the movable part can be smoothly transmitted to the blades. Reference numeral 10 in FIG. 2b is a dual-purpose blade that functions similarly to the shutter blade 9, and the sub-diaphragm portion 10b cooperates with the sub-diaphragm hole 12b on the regulation plate 12 to connect to a light-receiving element (not shown) for exposure control. It is designed to control the amount of light. Since this dual-purpose blade 10 also serves as the shutter blade 9, a corresponding relationship is obtained between the opening areas of the main and sub-diaphragms. If the shutter blade is made of plastic or the like, there is a risk of it being burned out by the strong light that is focused on it through the lens, so it is also effective to treat the surface with metal to prevent this. Reference numeral 11 denotes a shaft pin that forms the rotation axis of the shutter blade 9 and the dual-purpose blade 10, and can also be provided by molding integrally with the blade. Second
The regulating plate 12 shown in FIG. 1A has two holes 12c for positioning with the shaft pin 11, and is made of a thin steel plate or the like having the exposure control sub-diaphragm opening 12b as described above. 13 is a lead wire, and 14 is a stopper, which is implanted in the lower yoke substrate 7' and comes into contact with the end of the notch 4b of the movable part 4 to stop the movable part 4.
It restricts the rotation of the shutter to prevent it from turning too much, and also serves as a stopper when closing the shutter.

FIG. 4 is a diagram showing the positional relationship between the wire ring pattern on the movable part 4 and the magnets on the yoke. The magnets are arranged so that the same magnetic poles face each other. As a result, a magnetic field is formed between the opposing magnets, and the wire ring pattern 5 of the movable part 4 is rotatably arranged in the gap between these opposing magnets. Now, when a current is passed from the first end 5a to the second end 5b of the wire ring pattern 5 shown in the third figure, the current flows in the radial direction of the movable part 4, changing direction alternately between the central direction and the centrifugal direction. Since the magnetic field and direction of the current flowing in the radial direction of the movable part are reversed, the movable part 4 rotates about the optical axis by passing the current through the ring pattern. The above current is passed from the second end 5b to the first end 5a.
If the current is reversed so that the current flows in the direction shown in FIG. Third
As shown in the figure, the ring pattern 5 is printed on both the front and back sides of the board 4, and this is located at the intermediate point 5c.
are connected to each other. When a current is applied to the coil pattern from a certain direction, the current always flows in the same direction to the coil patterns located at the same position on the front and back sides of the substrate. In order to do this, the intermediate point 5c is placed at a position rotated by 90 degrees from the first end 5a, and the front and back patterns are connected using a hole 5d through which light or a shaft passes. In this way, even if a protrusion is formed in the conductive portion, the conductor will not hit the magnet or the yoke and become conductive. The above positions of the holes in the upper yoke 7 and the holes in the lower yoke 7' and the position of the notch 4b in the movable part 4 overlap at the midpoint of the rotational movement of the movable part, so that light, shafts, lead wires, etc. This can be used as a coupling axis for the front and rear optical systems, an optical path for a sub-diaphragm, and a space for lead wires. FIG. 1 shows one of these holes used as an opening for a sub-diaphragm.

Next, FIG. 5 is a mechanical diagram of a main part showing an embodiment in which a mechanical flash mechanism is provided in the aperture shutter of the present invention. In the figure, 15 is a film sensitivity setting lever, and 16 is a distance setting lever, each of which is linked to an information setting mechanism (not shown). 19 and 20 are springs that bias the levers 15 and 16 clockwise, so that the levers 15 and 16 are rotatable about shafts 21 and 22 located at the same position. 17 is pivotally supported at one end of the film sensitivity signal lever 15 by a pin 23, and is supported by a spring 18.
This lever is pressed against the end of the distance signal lever 16, and this lever is in contact with the end surface of the cam portion 4b' of the movable portion 4 of the electromagnetically driven aperture shutter. As a result, the rotatable amount of the movable portion 4 of the shutter is limited by the position of the lever 17. That is, the position of the lever 17 is determined by the combined value of the film sensitivity and distance set information, and the aperture value takes a value corresponding to the film sensitivity and distance when the lever 17 and the cam portion 4a come into contact with each other. If the flash mechanism is not used, the distance signal lever 16 is rotated using a lever (not shown) so that the lever 17 is at a position where it is removed from the cam portion.

FIG. 6 is a circuit connection diagram showing one embodiment of the control circuit for the electromagnetically driven aperture shutter of the present invention. In the figure, 100 is a power source battery, and 101 is a main switch which is always open and is operated by the first stroke of the release button. Reference numeral 102 denotes a release switch which is always closed and is operated by the second stroke of the release button or a focusing completion signal from an autofocus camera. resistance 10
3 and a capacitor 104 constitute a time constant circuit, and 10
5 is a timer circuit for preventing chattering upon release. 110 is a constant voltage circuit, and 111 is a light receiving element for photometry, in which an SPC is used. Applicable
SPC is connected between both input terminals of operational amplifier 112. 133 is a switching transistor for short-circuiting both ends of the capacitor 119, and its collector side is connected to the non-inverting input terminal of the comparator 121. A variable voltage source 120 for generating a film ASA sensitivity signal is connected to the inverting input terminal of the comparator 121. 123
are inverters, 126, 127, 128 and 1
29 are coil control transistors for controlling the direction of current supply to the coil 5, respectively.

The operation of this circuit configured as described above will be explained next.

First, when the main switch 101 is turned on, the release switch 102 is closed, so the output of the timer circuit 105 is at a low (L) level and the transistor 108 remains off. Therefore, since the transistor 133 is on, the voltage at the non-inverting input terminal of the comparator 121 is almost zero, the output of the comparator 121 is at L level, and the coil control transistors 127 and 12 are turned on.
8 is off. Further, the transistor 108
Since the switching transistor 132 is turned on since the coil control transistor 129 is turned off, the coil control transistor 129 is also turned off. The coil control transistor 126 is in a conductive state, but the other coil control transistors 127, 128 and 129
is off, the coil 5 is not energized and the electromagnetic device does not operate.

Next, when the release switch 102 is opened by the shutter release operation, after a certain period of time determined by the resistor 103 and capacitor 104, the timer circuit 105 is turned on and its output is reversed from L level to high (H) level. From transistor 10
8 is turned on. As a result, the transistor 132
and 133 are turned off. At this stage, the output of the comparator 121 remains at L level, so the transistor 131 is turned off. As a result, the coil control transistor 129 is turned on, but since the coil control transistors 127 and 129 remain on and the coil control transistor 126 is on, the coil pattern 5 on the movable part is The current is applied and the shutter starts to open. At the same time, light enters the SPC 111 through the sub-diaphragm aperture, and a current proportional to the amount of incident light flows into the capacitor 119. When the terminal voltage of the capacitor 119 reaches a voltage set by the ASA sensitivity of the film, the output of the comparator 121 is inverted from the L level to the H level. As a result, the coil control transistors 127 and 128 are turned on, and the coil control transistor 12 is turned on via the inverter.
6 is turned off. Furthermore, when the switching transistor 131 is turned on, the coil control transistor 129 is also turned off. As a result of the above, a current in direction B is now applied to the wire ring pattern 5 on the movable part, and the closing movement of the shutter begins.

Next, the operation of the electromagnetically driven aperture shutter of the present invention shown in FIGS. 1 to 6 will be explained. The circuit is activated by the release operation and the wire pattern 5
A drive current flows from the first end 5a to the second end 5b.

The coils and magnets are arranged as shown in Figure 4, and there is a pattern radial component in the opposing magnetic field, and the current component flowing in the radial direction of the movable part is caused by the magnetic field in the optical axis direction to change the circular shape of the movable part. It is designed to receive force in the tangential direction. In the 12 force-generating parts, the direction of current flow and the direction of the magnetic field are alternately reversed, so the movable part performs rotational motion. This rotational movement moves the shutter blade 9 and blade 10 by the sector pin 8, and the sub-diaphragm 12
b and the light passing through the sub-diaphragm part 10b is transmitted to the light receiving element 110.
When it is determined that the exposure is appropriate, the electric circuit is activated and the current is applied to the second end 5 of the pattern.
From b to the first end 5a, the rotational movement of the movable part is reversed and the shutter is closed.

In addition, when fully opened or closed, the movable part 4 is braked by the stopper 14 and positioned.

Normally, the movable part is pressed in the shutter closing direction by a spring/lead wire 1 to prevent the shutter from opening due to vibration or the like.

When using a mechanical flash mechanical mechanism, a lever (not shown) releases the distance signal lever 16 shown in FIG. 17 is determined, and the movable part 4 is attached to this position.
When the cam portion comes into contact with the movable portion, the aperture value that is directly connected to the movable portion is determined, and flash photography is performed.

The electromagnetic drive shutter of the present invention is an aperture shutter that also serves as a shutter blade, and uses a spring as shown at 1 in FIG. 1 in order to obtain desirable operating characteristics as an aperture shutter. The operational characteristics of the shutter when this spring 1 is not used are symmetrical between the open and closed positions, as shown in FIG.
By adding the spring 1, the operating characteristics of the shutter can be made to have different opening characteristics and closing characteristics as shown in FIG. In FIG. 8, the shutter blade performs an opening/closing operation for a time t ₆ with respect to an opening amount f ₃ . During this exposure time, in the case of a shutter without a spring (Fig. 7), the blade changes from opening to closing action at t ₃ , whereas when a spring is added (Fig. 8) So this becomes t ₃ ′. As is clear from the figure, t ₃ ′>t ₃ and the slope of the aperture characteristic becomes gentler when a spring is added. Delay time ta from when the shutter close signal is input until the shutter close operation starts
is the same in Figures 7 and 8, so this time ta
The amount of change in the opening amount f ₃ in FIG. 7 is larger in FIG. 7, and smaller in FIG. 8 where a spring is added. That is, even if the absolute value of the variation Δta in the delay time ta is the same, the influence of the variation on the shutter opening amount can be made smaller when a spring is added (FIG. 8). Furthermore, the acceleration of the shutter blades when a spring is applied is the restoring force of the spring added to the force generated by the rotation of the movable part during the closing operation, and this is greater than the acceleration without the spring. As shown in FIG. 8, the closing operation is performed rapidly. In this way, by adding a spring in the closing direction, the mechanical delay in shutter blade operation can be reduced, and the fluctuation in opening amount due to variations in this time delay can be reduced, resulting in desirable operating characteristics for a programmable shutter. It is.

As described above, in the present invention, a wave-shaped conductor is provided on the rotor of an electromagnetic drive shutter, and notches are formed along the wave-shaped pattern of the conductor, thereby generating the necessary electromagnetic driving force in the rotational direction of the rotor. While this is possible, the rotor can be made lighter and responsiveness can be improved. Furthermore, according to the present invention, even when the rotor is formed of a thin material, it is possible to prevent distortion of the rotor due to deformation of the rotor, etc., so that the rotor can be operated in a relatively narrow magnetic field space. It is possible to efficiently generate electromagnetic driving force with low power.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the electromagnetically driven aperture shutter according to the present invention, FIG. 2 is an exploded perspective view of the shutter shown in FIG. 1, and FIG. FIG. 4 is a partial perspective view showing the relationship between the magnets arranged in the fixed parts of FIGS. 2b and d and the wire pattern, and FIG. 5 is a plan view showing an example of the wire pattern according to the present invention. Fig. 6 is a circuit connection diagram showing an embodiment of the control circuit for the electromagnetically driven diaphragm shutter of the present invention; FIG. 8 is a shutter operating characteristic curve diagram when the panel shown in FIG. 1 is not used, and FIG. 8 is a shutter operating characteristic curve diagram when a spring is used. 1... Connection wire that also serves as a spring, 2... Shutter outer casing, 3... Insulating sheet, 4... Movable part (sector ring), 5... Wire ring pattern, 6... Magnet, 7
... Yoke board, 8 ... Sector pin, 9 ... Shutter blade, 10 ... Dual-purpose blade, 11 ... Axis pin, 12 ... Maximum diameter regulating plate, 13 ... Lead wire, 14 ... Stopper, 15 ... ...Film sensitivity signal lever, 16...Distance signal lever, 17...
Flash mechanical lever.

Claims (1)

[Scope of Claims] 1. A vane that controls the amount of light in a photographing optical path, a rotor that rotates to drive the vane, and a wave-like shape around the rotor that alternately follows the radial direction and circumferential direction of the rotor. and a magnetic circuit that applies a magnetic field in a predetermined direction to the conductor, and the rotor has a plurality of notches formed along the wave pattern of the conductor. Features an electromagnetic drive shutter. 2. The electromagnetic drive shutter according to claim 1, wherein the opening degree of the blade is controlled through one of the plurality of notches.