JPS6232270Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a shutter device that controls the exposure amount by performing sub-diaphragm photometry, and particularly relates to an improvement for optimizing the EE characteristics.

In general, in shutter devices that control the exposure amount by performing sub-aperture metering, if the driving force fluctuates, the estimated control amount will change, the EE characteristics will be distorted, and the exposure will be inappropriate, especially at small apertures. I had some inconveniences when I got used to it.

The present invention was made to solve the above-mentioned disadvantages, and includes an exposure blade member, a photometry blade member that operates in conjunction with the exposure blade member, and a photometry aperture formed together with the photometry blade member. and a positionally adjustable adjustment member that adjusts the opening start timing of the photometric aperture by changing the overlapping positional relationship with the photometric blade, the opening of the photometric aperture preceding the exposure aperture. The present invention aims to provide a shutter device that corrects changes in aperture characteristics due to fluctuations in the driving force of the shutter by adjusting the start timing and makes the EE characteristics appropriate.

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 electromagnetic drive shutter. Fig. 1 shows the main structure of the electromagnetic drive shutter. The members 3 are 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, 1 that also serve as
0, a guide plate 11 made of a magnetic material, a rotor 12, and a positioning member 14 equipped with a permanent magnet 13 are interposed in this order. On the back of the second board 6 is a printed circuit board 1.
5 is placed. 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 photographing 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 . In addition, the first board 5, the guide plate 11, the positioning member 14, and the printed board 15 have a printed board 15.
A sub-diaphragm aperture is provided for the upper light-receiving element 16 to measure the subject brightness, and the aperture diameter of this light path is determined by the shutter blade 8 and the sub-diaphragm blade 16. The first board 5 and the guide plate 11 are connected by screws 1
It is attached by 7. Shutter blade 8,
9 and 10 are arranged together with the regulating member 7 between the first substrate 5 and the guide plate 11, and the protrusions 5a and 5b of the first substrate 5 form a movable space for the shutter blades 8, 9, and 10. It is. Further, pins 11a, 11b, 11c are installed around the bearings of the guide plate 11, and these pins 11a, 11b, 11c serve as rotation axes of the shutter blades 8, 9, 10, and The regulating member 7 is inserted into the hole of the first substrate 5. In addition, the guide plate 11 also includes implant pins 12a from the rotor 12,
Guide holes are provided for inserting the pins 12b and 12c, and the pins 12a and 1 are inserted from the rotor 12.
2b and 12c serve as drive shafts for the 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 the second
It constitutes the magnetic field indicated by diagonal lines in the figure.

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 held stationary at a stopper 19. This stopper 19 is eccentric, and by adjusting the eccentric state of the stopper 19, the rotor 1
The rest position of 2 can be adjusted. Rotor 1
2 has coils 20 patterned on both sides, and the coils 20 on both sides are electrically connected by one drive pin 12b. The rotor 12 has a coil 20 disposed thereon and 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 of the same quality 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

Therefore, in an electromagnetic drive shutter incorporating the rotor 12, when a current is applied to the coil 20 of the rotor 12 from a circuit (not shown) using the lead wires 21a and 21b, the magnetic flux of the permanent magnet 13 causes the coil 20 to
0, an electromagnetic force is generated according to Fleming's left-hand rule, causing the rotor 12 to rotate counterclockwise against the springs 18a and 18b, opening the shutter blades 10, 8, and 9, which also serve as the main diaphragm. operate in the direction.
First, the corner 2 of the mask portion 22a of the sub aperture blade 22
The aperture of the sub-diaphragm as a photometric aperture begins between _2a1 and the sub-diaphragm window 8a of the shutter blade 8. The time in seconds at this time is shown as _t1 in FIG. As a result, the subject light enters the light receiving element 16. As the aperture of the sub-diaphragm advances, the shutter starts to open as an exposure aperture at time _t2 , and exposure of the film 4 is started. Eventually, the sub-diaphragm fully opens at _t3 , but at this time the shutter is still open. The sub-diaphragm is then narrowed down a little to reduce the effect of bounce (second time t ₄ ) and the shutter is fully opened. At this time, the aperture area of the sub-diaphragm is 1/2 that of when it is fully open. Then, a photometric calculation based on the output of the light receiving element 16 is performed by a circuit (not shown), and based on this calculation output, the rotor 12
The current in the coil 20 is cut off. As a result, rotor 12
The shutter blades 10, 8, and 9 are rotated back by the spring pressure of the springs 18a and 18b to close 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.

If the electromagnetic force is set to be large by the above operation and the exposure amount at a small aperture becomes excessive, move the adjustment section 22b to advance t ₁ to t ₁ ' and rotate the sub-diaphragm blades 22 counterclockwise. . Then, the aperture characteristic changes as shown by the left line in FIG. 3, and a signal from a circuit (not shown) is output more quickly, thereby compensating for excessive exposure when the aperture is small.

On the other hand, if the electromagnetic drive is small and the exposure amount is undersized at a small aperture, adjust the adjustment unit 2 to slow down t ₁ to t ₁ ″.
2b to rotate the sub aperture blade 22 clockwise. In this case, the sub-diaphragm aperture characteristic will be as shown by the line on the right side of FIG. 3, and the closing signal from the circuit (not shown) will be output later, thereby compensating for the underexposure when the aperture is small. At this time, the rotation center axis of the sub-diaphragm blades 8, the rotation center axis of the sub-diaphragm blades 22, and the corner 22a ₁ of the mask portion 22a of the sub-diaphragm blades 22.
By configuring the sub-diaphragm on a straight line, deterioration of the sub-diaphragm shape due to adjustment of the sub-diaphragm blades is reduced. In other words, the maximum change in time can be obtained with the minimum mask movement.

For this reason, it is effective to make the adjustment part 22b sufficiently long from the axis. Also, by making it sufficiently long, magnetic dust attached to the sub-diaphragm blade 8 or the adjustment tool will be transferred to the permanent magnet during adjustment. This can prevent it from being attracted and causing a malfunction.

When a coil in a magnetic field is driven by electromagnetic force due to energization, the rotor and shutter blades are constantly accelerated and perform accelerated motion with increased kinetic energy. Therefore, the movement speed of the shutter blade is slow at the time when the sub-diaphragm starts to open, and at this point, even a slight position adjustment will greatly increase the speed in terms of the seconds at which the sub-diaphragm starts opening. On the other hand, even if the aperture start timing is adjusted in this way, as the sub-diaphragm approaches full opening, the amount of movement for the position adjustment will be reduced in terms of seconds until the sub-diaphragm fully opens (since the speed is faster, it will remain the same 0.1
The time it takes to pass mm has become very small) and can be ignored.

The fluctuation in the main aperture exposure amount when the power is turned off due to changes in the driving force is mainly due to the inertia of the shutter at the time when the power is turned off, and the greater the driving force, the greater the exposure amount after the power is turned off. Similarly, the effect becomes greater when the control period is short and the aperture is small.

As mentioned above, adjusting the sub-aperture position without changing the main aperture time elapsed means adjusting the lead time of the sub-aperture relative to the main aperture, especially when the aperture is small, and this changes the driving force. It is extremely effective against deterioration of EE characteristics due to

As described above, according to the present invention, the amount of advance of the sub-diaphragm aperture that precedes the main aperture is adjusted in response to changes in the aperture characteristics due to changes in the driving force of the shutter, thereby flattening the EE characteristics. It is possible to make it happen.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an electromagnetic drive 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 an aperture characteristic diagram of the sub-diaphragm. 10, 8, 9...Shutter blade that also serves as a main diaphragm, 12...Rotor, 13...Permanent magnet, 20...
...Coil, 19...Stopper, 22...Sub-aperture blade.

Claims (1)

[Scope of utility model registration request] An exposure blade member, a photometric blade member that operates in conjunction with the exposure blade member, and a photometric aperture formed together with the photometric blade member, and a positional relationship of overlapping with the photometric blade member is changed. A shutter device comprising: an adjusting member whose position is freely adjustable and adjusts the opening start timing of the photometric aperture.