JPS6239405B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shutter device that prevents the influence of bounce of shutter blades.

Generally, the shutter blade hits a stopper at the fully open position and stops, so bounce occurs when the shutter blade reaches the fully open position.

The bounce of the shutter blade means that the shutter blade repeatedly moves in the closing direction and in the opening direction for a short time near the stopper due to the impact of the shutter blade colliding with the stopper. If a shutter close signal is applied while the shutter blade is bouncing, an error will occur in the exposure amount due to the bounced state of the shutter blade. In other words, if the shutter close signal is applied while the shutter blade is bouncing in the opening direction and the shutter closes, the time lag between when the shutter close signal is generated and when the shutter blade actually operates is relatively short. big. However, if the shutter closes when a shutter close signal is applied while the shutter blade is bouncing in the closing direction, the time lag between when the shutter close signal is generated and when the shutter blade actually operates is relatively short. few. Therefore, when the shutter blade bounces, there is a considerable difference in the amount of exposure depending on the bounce state, resulting in an inappropriate exposure state.

The present invention has been made in view of the above circumstances, and includes an exposure blade member, a first opening that opens in conjunction with the opening operation of the exposure blade member, and the exposure blade member that reaches its full opening. A photometric blade member that sequentially forms a second aperture that first performs a closing operation to reduce the amount of incident light, and then a third aperture that corresponds to the full opening of the exposure blade member by shifting to an opening operation again. The object of the present invention is to provide a shutter device which can obtain appropriate exposure by preventing the shutter close signal from being generated during bounce when the shutter is fully open.

An embodiment of the present invention will be described below with reference to the drawings.
The following embodiments show the case where the present invention is applied to an electromagnetically driven shutter, and FIG. 1 shows the main structure of the electromagnetically driven shutter.
2 is a holding member for the photographic lens 1, 3 is a light-shielding tube, and 4 is a film. An electromagnetically driven shutter unit is interposed between the holding member 2 and the light shielding tube 3. This electromagnetic drive shutter unit has a first substrate 5 and a second substrate 6 made of a magnetic material, and between the first substrate 5 and the second substrate 6 there is a shutter opening movement range regulating member 7 and a diaphragm. Three synthetic resin shutter blades 8, 9, 10, a guide plate 11 made of a magnetic material, a rotor 12, and a permanent magnet 13.
A positioning member 14 having a positioning member 14 is interposed in order. A printed circuit board 15 is arranged on the back surface of the second board 6. The first substrate 5, the regulating member 7, and the positioning member 14 are provided with an opening through which the subject light from the photographic lens 1 passes, and shutter blades 8, 9, and 10 are provided to block the path of this light. There is. The guide plate 11 and the rotor 12 are positioned on the bearing portion of the positioning member 14 . Further, the first substrate 5, the guide plate 11, the positioning member 14, and the printed circuit board 15 are provided with a sub-diaphragm aperture for allowing the light receiving element 16 on the printed circuit board 15 to measure the subject brightness, and the path of this light is The aperture diameter is determined by the blades 8 and the sub-diaphragm blades 16. The first board 5 and the guide plate 11 are attached with screws 17. The shutter blades 8, 9, 10 are disposed together with the regulating member 7 between the first substrate 5 and the guide plate 11, and the protruding portions 5a, 5 of the first substrate 5
b forms a movable space for the shutter blades 8, 9, and 10. Also, around the bearing of the guide plate 11 is a pin 1 that serves as a rotation axis for the shutter blades 8, 9, 10.
1a, 11b, 11c are implanted, and these pins 11a, 11b, 11c are connected to the shutter blades 8, 9,
10 and the regulating member 7, and is inserted into the hole of the first substrate 5. Further, on the guide plate 11 there are installed pins 12a, 12b, 12 from the rotor 12.
A guide hole for inserting the pins 12a, 12b, 12c from the rotor 12 is provided.
serves as a drive shaft for shutter blades 8, 9, and 10. The positioning member 14 is provided with four pairs of permanent magnets 13 that are magnetized in the thickness direction and have different polarities. This permanent magnet 13 constitutes a magnetic circuit with the second substrate 6 and the guide plate 11, and constitutes a magnetic field shown by diagonal lines in FIG.

FIG. 2 shows the rotor 12 and shutter blades 8,
9 and 10 are specifically shown, and the guide plate 11 is omitted because it would make the diagram complicated.

The rotor 12 is biased clockwise by springs 18a and 18b and is stopped at a stopper 19. This stopper 19 is eccentric, and by adjusting the eccentric state of the stopper 19, the resting position of the rotor 12 can be adjusted. The rotor 12 has coils 20 patterned on both sides, and the coils 20 on both sides are electrically coupled by one drive pin 12b. A coil 20 disposed on the rotor 12 is connected to a lead wire 2 on the inner surface of the rotor 12.
1a and 21b, and these lead wires 21a and 21b are arranged in a predetermined length using the space between the bearing part of the positioning member 14 and the permanent magnet 13 as a bending space, and are taken out to the outside (not shown). connected to the drive circuit. Since the drive pin 12b has a potential, the shutter blades 8, 9, and 10 are made of an insulating nonmetal, for example, a polyester sheet dyed black. A sub-diaphragm window 8a is formed in the shutter blade 8, and this window 8a, together with the mask portion 22a of the sub-diaphragm blade 22, constitutes a sub-diaphragm. This sub aperture blade 22 moves the adjustment section 22b and adjusts the mask section 22a. The rotor 12 is made of synthetic resin such as glass epoxy. Stopper 1 of this rotor 12
In the portion corresponding to 9, metal from the same chamber as the coil remains, and serves as reinforcing metal portions 23a and 23b. These reinforcing metal parts 23a and 23b are reinforced with the strength of metal, and are used to prevent cracks from occurring due to impact when movement is restricted by the stopper 19. Furthermore, metal of the same quality as the coil 20 remains on the outer periphery of the end portion and the inner periphery of the end portion of the rotor 12, forming an outer periphery metal portion 23c and an inner periphery metal portion 23d.
The outer metal part 23c prevents cracks from occurring due to impact during press working, and the inner metal part 23d
This prevents the effects of thermal expansion due to temperature changes and allows the rotor 12 to rotate smoothly relative to the positioning member 14. Also spring 1
The attachment parts 8a and 18b also serve as reinforcement parts 23e and 23f. A cover 24 is attached to the coil 20 of the rotor 12, and a cover 24 is attached to the coil 20 and the guide plate 11.
prevents electrical contact between the

Next, the operation of the above configuration will be explained with reference to FIGS. 3 to 6.

When a current is passed through the coil 20 of the rotor 12 from a circuit (not shown) through the lead wires 21a and 21b, an electromagnetic force is generated in the coil 20 by the magnetic flux of the permanent magnet 13 according to Fleming's left hand rule, and the rotor 1
2 in the counterclockwise direction against the springs 18a, 18b, the shutter blades 10, 8, which also serve as the main aperture
9 in the direction of opening. Initially, at the starting position, the mask portion 22 of the sub-aperture blade 22 as shown in FIG.
A is only slightly opened for pre-display, but this slightly opened mask portion 22a is also fully closed at ₁ second t shown in FIG. 3 from the start of energization. Then, after t ₂ seconds in FIG. 3, the sub-diaphragm begins to open between each 22a ₁ of the mask portion 22a of the sub-diaphragm blade 22 and the sub-diaphragm window 8a of the shutter blade 8. As a result, the subject light enters the light receiving element. As the aperture of the sub-diaphragm increases, the third
After t3 seconds in the figure, the shutter starts opening and exposure of the film 4 is started. Eventually, the sub-diaphragm opens fully at _t4 seconds in Figure 3, resulting in the state shown in Figure 4, but at this time the shutter is still open. Eventually, the sub-diaphragm begins to close, and after ₅ seconds from t in Figure 3, it is stopped down to its maximum, resulting in the state shown in Figure 5. At this time, almost no light enters the light receiving element 16, making it difficult for a shutter close signal to be output from a circuit (not shown). Then, the sub-diaphragm starts to open again, and at _t6 seconds in FIG. 3, the shutter is fully opened, and the sub-diaphragm has an opening amount of 1/2 of the full opening, and this state is shown in FIG. Then, a photometric calculation based on the output of the light receiving element 16 is performed by a circuit (not shown), and the current in the coil 20 of the rotor 12 is cut off based on the calculation output. As a result, the rotor 12 is rotated back by the spring pressure of the springs 18a and 18b, thereby closing the shutter blades 10, 8, and 9. At this time, the rotor 12 is prevented from rotating and stopped at the position of the stopper 19.

As described above, in the present invention, there is a time lag between the generation of the shutter closing signal and the start of the shutter closing operation, and the extra exposure amount due to this time lag is unnecessary for exposing the film. Therefore, the exposure amount is corrected by starting the opening operation of the sub-diaphragm prior to the start of the shutter opening operation by this time lag, but the exposure amount error is not only due to this, but also when the shutter drive rotor bounces. It also occurs in For this reason, the present invention reduces the aperture of the sub-diaphragm when the sub-diaphragm is opened in accordance with the time when bounce occurs, so that the shutter close signal is less likely to be generated at this time, and thereby prevents the influence of exposure error due to bounce. This is what I did. Although the opening of this sub-diaphragm is not completely closed in the embodiment, it may be completely closed.

If the effects of exposure errors due to bounces are prevented in this way, the shutter will be closed immediately after the bounce ends and the shutter is fully opened, even though it should actually be closed when the bounce occurs. For this reason, if the exposure time is longer than that, the exposure time will increase slightly, resulting in some overexposure, but since it is on the long side, even if the exposure time increases slightly, it will be relatively small, and the overall exposure level fluctuations do not occur that much.

Further, the amount of extra exposure due to the time lag between the generation of the shutter closing signal and the time when the shutter actually starts to close differs between during the opening operation up to full opening of the shutter and after the shutter is fully opened. In other words, since the shutter that also serves as an aperture is a half-open type shutter,
The shutter opening characteristic has a triangular shape until the shutter is fully opened, and a trapezoidal shape after the shutter is fully opened. Therefore, the rate at which the extra exposure amount occurs due to the time lag is different between the shutter opening operation until the shutter is fully opened and after the shutter is fully opened. For this reason, in the present application, in order to correct this change in the ratio with the aperture state of the sub-diaphragm, after the sub-diaphragm is stopped down, the sub-diaphragm is not fully opened but is set to 1/2 the opening amount.

As detailed above, according to the present invention, by changing the aperture characteristics of the sub-diaphragm, it is possible to prevent exposure errors due to bounce and the effects of excessive changes in exposure amount before and after the shutter is fully opened due to time lag. Good EE characteristics can be obtained,
Its effectiveness is extremely high.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an electromagnetic shutter showing an embodiment of the present invention, Fig. 2 is a detailed view of the rotor and shutter shown in Fig. 1, and Fig. 3 is a main aperture shown in Figs. 1 and 2. and aperture characteristic diagrams of the sub-diaphragm, Figures 4 to 6.
The diagram explains the operation of the main parts of Figure 2.
FIG. 4 is an explanatory diagram when the sub-diaphragm is fully open, FIG. 5 is an explanatory diagram when the sub-diaphragm is closed, and FIG. 6 is an explanatory diagram when the sub-diaphragm is half-open and the main aperture is fully open. 10, 8, 9... Shutter blade that also serves as the main diaphragm, 12... Rotor, 13... Permanent magnet, 18
a, 18b... Spring, 19... Stopper, 20...
...Coil, 22...Sub-aperture blade.

Claims (1)

[Claims] 1. An exposure blade member, a first opening that opens in conjunction with the opening operation of the exposure blade member, and a first opening that temporarily closes to reduce the amount of incident light before the exposure blade member reaches its full opening. 1. A shutter device comprising a photometric blade member that sequentially forms a second aperture and a third aperture that corresponds to the fully opening of the exposure blade member by shifting to an opening operation again.