JP2006071892A - Diaphragm controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain variations in the amount of diaphragm caused by fluctuations in the rotating speed of a rotor. <P>SOLUTION: The diaphragm controller comprises: a rotor 14 designed so as to rotate accompanying the diaphragming operation of a diaphragm and lock the diaphragm by the stop of the rotation; an armature lever 26 attracted and held by an electronic device 23 during the diaphragming operation, and allowed to start rotation in a predetermined direction by a pressing force exerted upon the cancellation of attraction needed to lock the diaphragm; and engagement claw member 31 having a claw 31b, rotatably supported by the armature lever 26, and adopted to stop the rotation of the rotor 14 by the engagement of the claw 31b with the rotor 14 caused as a result of the rotation of the armature lever 26; and a pressing member 32 for pressing the engagement claw member 31 in the direction of the reverse of the direction in which the engaging claw member 31 bounces when the claw 31b collides with the rotor 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an aperture control device for a camera, and is intended to reduce variations in aperture amount caused by a temperature environment and other factors.

  A diaphragm control device provided in a single-lens reflex camera forcibly stops rotation by engaging a claw with a tooth of a ratchet wheel that rotates in accordance with a narrowing operation, and locks the diaphragm in a desired narrowed state. The claw is formed on an armature lever that can be attracted and held by an electromagnetic device. The control device of the camera monitors the rotation of the ratchet wheel from the start of the narrowing down, releases the attracting force by the electromagnetic device when the rotation amount becomes an amount corresponding to the set aperture value, and makes the armature lever free. The free armature lever is rotated by the urging force of the urging spring, and its claw engages with the teeth of the ratchet wheel to stop it, and stops the squeezing (locks the squeezing).

  Since there is a time lag between the release of the armature lever and the stop of the aperture, the aperture cannot be locked accurately in the desired stop state unless the release timing of the armature lever is determined in consideration of the delay. . An aperture control device that takes this point into account is described in, for example, Japanese Patent Application Laid-Open No. H10-228707.

JP 7-295023 A

  One factor of the time lag until the stop of the aperture is the bounce of the armature lever. That is, at the moment when the armature lever claw collides with the tooth of the ratchet wheel when it collides with the tooth, the armature lever bounces in the direction opposite to the engaging direction around the rotation axis due to the impact force. Although the bounce can be suppressed by increasing the force of the spring that urges the armature lever, the bounce suppression by the spring force has a limit because it cannot be urged by a force greater than the adsorption holding force by the electromagnetic device. After the bounce, the armature lever is rotated again in the engagement direction by the urging force of the urging spring, and is eventually engaged. Therefore, it is necessary to control how to estimate how much the ratchet wheel rotates while the armature lever bounces, and to release the armature lever as early as the estimated amount.

  However, since the rotation speed of the ratchet wheel (depending on the speed of narrowing) varies depending on various factors such as environmental temperature, lubrication, and wear of parts, the amount of rotation of the ratchet wheel during the armature lever bounce is also constant. Absent. For this reason, unless the release timing of the armature lever is originally determined in consideration of the above factors, the actual narrowing amount varies, and the variation becomes remarkable particularly when the armature lever bound time is long. Other factors that cause variations in the amount of aperture reduction include the fact that the urging force of the lens aperture lever varies from lens to lens, and the voltage applied to the electromagnetic device that attracts the armature lever varies depending on the remaining amount of the power battery. . However, as an actual problem, it is extremely difficult to perform aperture control in consideration of the above various factors, which is not practical.

The diaphragm control device according to the first to third aspects of the present invention is rotated as the diaphragm is squeezed, and is rotated and held by the electromagnetic device during the squeezing. When suction is released to lock the diaphragm, it has an armature lever that starts rotating in a predetermined direction by an urging force, and a claw, and is rotatably supported by the armature lever. The engaging claw member that stops the rotation of the rotating body by engaging with the rotating body, and the engaging claw member in a direction opposite to the direction in which the engaging claw member bounces when the claw collides with the rotating body. And a biasing member for biasing.
According to a second aspect of the present invention, an action line of a force that the armature lever receives from the rotation shaft of the engaging claw member during the collision passes through the rotation shaft of the armature lever.
The invention of claim 3 determines the suction release timing of the armature lever for locking the aperture at the target aperture stage from the storage device in which data for aperture locking is stored in advance and the data in the storage device, And a control device for releasing the suction at the determined timing.
According to a fourth aspect of the present invention, there is provided a diaphragm control device that operates as the diaphragm is squeezed down, and that the operation is stopped to stop the diaphragm and a predetermined member to lock the diaphragm in a predetermined squeezed state. And a claw that is pivotally supported by the aperture locking lever. The claw engages with the operating member by the rotation of the aperture locking lever. And an urging member that urges the engaging claw member in a direction opposite to the direction in which the engaging claw member bounces when the claw collides with the operating member.
The diaphragm control device according to the inventions of claims 5 to 7 rotates as the diaphragm is squeezed, and the rotation body that stops the rotation to stop the diaphragm, and is held by suction to the electromagnetic device during the squeezing, When the suction is released to lock the diaphragm, the armature lever that starts to rotate in a predetermined direction by the urging force and the rotating body are engaged by the rotation of the armature lever, and the rotation of the rotating body is stopped. A claw, a pulse generator that outputs a number of pulses corresponding to the amount of rotation of the rotating body, a number of pulses that are output from the release of the armature lever suction to the stop of the aperture, and the predicted number of pulses and the rotating body When the sum of the number of output pulses from the start of rotation reaches the number of pulses corresponding to the target aperture stage number, signal output means for outputting a locking signal, and a predetermined delay time has elapsed from the output of the locking signal Later of the armature lever And a control device for releasing the wear.
According to a sixth aspect of the present invention, the delay time is a time obtained by multiplying a pulse output interval time by a coefficient set in advance according to the target aperture stage number.
According to a seventh aspect of the invention, the coefficient is stored in advance in a storage device.

Thus, according to the first aspect of the present invention, the claw to be engaged with the rotating body is not provided on the armature lever, but is provided on a member (engagement claw member) supported rotatably on the armature lever, and the engagement claw. The member was biased in the direction opposite to its bound direction. The engaging claw member can be made lighter and smaller than the armature lever, and the force that biases it can be increased, so that the natural frequency when the engaging claw member bounces can be higher than when the armature bounces. Time can be shortened. If the bounce time is shortened, even if the rotational speed of the rotating body fluctuates due to various factors such as environmental temperature, lubrication, and parts wear, variation in the amount of rotation of the rotating body during the bounce can be suppressed. It is possible to suppress variations in the amount of narrowing down without performing complicated control.
In the invention of claim 5, the number of pulses output from the armature lever suction release to the stop of the aperture is predicted, and the sum of the predicted number of pulses and the number of output pulses from the start of rotation of the rotating body is the target aperture. The armature lever is released from the suction after a predetermined delay time has elapsed since the number of pulses corresponding to the number of stages has been reached. By providing the delay time in this way, it is possible to reduce the influence of factors that cause variations in the amount of narrowing down and reduce the variations.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows the configuration of a diaphragm control device for a camera in this embodiment. The aperture control device controls the aperture by positioning the aperture lever 3 of the interchangeable lens mounted on the camera. The aperture lever 3 is urged in the direction A by a spring (not shown) in the lens, and moves in the A direction to narrow the aperture.

  The diaphragm control lever 4 engaged with the diaphragm lever 3 when the lens is mounted has a sector gear portion 4a, a spring hook portion 4b, and bending portions 4c and 4d, and can be rotated together with the drive lever 6 on the shaft 5 on the substrate 1. The spring 7 is supported and is urged clockwise by the spring 7 latched by the spring hook 4c and the spring hook 1a of the substrate 1.

  The drive lever 6 has bent portions 6a and 6b and a pin 6c, and is connected to the aperture control lever 4 by a spring 8 hooked between the bent portion 6a and the spring hook portion 4b. The pin 6 c restricts the rotation of the aperture control lever 4 with respect to the drive lever 6. The bent portion 6b can be engaged with a latching portion 15b provided at one end of the locking lever 15, and the clockwise rotation of the drive lever 6 is prevented when engaged. At this time, the aperture control lever 4 is prevented from rotating clockwise by the spring 8, and therefore the bent portion 4 d of the aperture control lever 4 prevents the movement of the lens aperture lever 3 in the A direction. Is kept open.

When the aperture control lever 4 rotates clockwise, the aperture lever 3 moves in the A direction following the movement of the bending portion 4d, and the aperture is narrowed down. The aperture amount depends on the rotation angle of the aperture control lever 4 (the amount of movement of the aperture lever 3).
The reason why the drive lever 6 and the spring 8 are provided is to automatically adjust the position of the bent portion 4d of the aperture control lever 4 with respect to the variation in the position of the aperture lever 3.

  The locking lever 15 is rotatably supported by the shaft 16, and an interlocking portion 15 c provided at the other end can be engaged with a bent portion 18 a of the aperture start lever 18. The spring 17 is locked to the bent portion 15a of the locking lever 15 and the shaft 30, and urges the locking lever 15 clockwise. The aperture start lever 18 has bent portions 18b and 18c in addition to the bent portion 18a, and is supported by the shaft 13 so as to be rotatable. A start spring 22 is engaged with the bent portion 18b and the bent portion 1b of the substrate 1, and the aperture start lever 18 is urged clockwise by the urging force thereof. Further, the bent portion 18c engages with the iron core 21 attracted and held by the permanent magnet 19a of the start magnet 19, and when the attracting force of the permanent magnet 19a is exerted, the clockwise rotation of the aperture start lever 18 is prevented. Is done. The start magnet 19 is fixed to the substrate 1 with screws 20a and 20b.

  On the other hand, the sector gear portion 4 a of the aperture control lever 4 described above meshes with the pinion gear 9 that is rotatably supported by the shaft 10, so that the pinion gear 9 rotates according to the rotation of the aperture control lever 4. A ratchet gear 12 meshes with the large gear 11 that rotates integrally with the pinion gear 9, and the ratchet gear 12 rotates around the shaft 13 together with the ratchet wheel 14. As shown in the enlarged view of FIG. 2, the ratchet wheel 14 has a plurality of long holes 14a formed at equal angular intervals, and a plurality of teeth (ratchet teeth) 14b formed on the outer periphery. A rotation speed sensor (photo interrupter) 33 is provided so as to sandwich the elongated hole forming portion of the ratchet wheel 14, and the rotation speed sensor 33 outputs a number of pulses corresponding to the feed amount (rotation amount) of the ratchet wheel 14. As is apparent from the figure, one pulse is output for each tooth feed. The number of pulses depends on the rotation angle of the aperture control lever 4, that is, the amount of aperture reduction. The rotation speed sensor 33 is fixed to the substrate 1 by means not shown.

  The ratchet wheel 14 is forcibly stopped by engaging the claw 31b of the claw member 31 with the tooth 14b, and the rotation of the aperture control lever 4 is stopped accordingly, and the aperture is in the apertured state at that time. It is locked with. The claw member 31 is rotatably supported by a shaft 28 protruding from the armature lever 26, and the armature lever 26 is rotatably supported by a shaft 27. The spring 29 is hooked on the bent portion 26c of the armature lever 26 and the pin 30, and urges the armature lever 26 counterclockwise. The spring 32 is hooked on the claw 31 b of the claw member 31 and the bent portion 26 a of the armature lever 26 to urge the claw member 31 counterclockwise with respect to the armature lever 26. The claw member 31 has its positioning portion 31 a (FIG. 2) abutted against the bent portion 26 c of the armature lever 26, so that its counterclockwise rotation is restricted, and normally maintains a certain posture with respect to the armature lever 26. .

  The bent portion 26b of the armature lever 26 engages with the iron core 25 attracted and held by the permanent magnet 23a of the aperture stop magnet 23, and when the attracting force of the permanent magnet 23a is exerted, the lever 26 rotates counterclockwise. Movement is blocked. The aperture stop magnet 23 is fixed to the substrate 1 by screws 24a and 24b.

  The substrate 1 supporting each component described above is fixed to a camera body (not shown) by screws 2a to 2c, and the magnets 19 and 23 and the rotation speed sensor 33 are electrically connected to the CPU 34 shown in FIG. A storage device 35 that stores various information is also connected to the CPU 34.

  In the aperture control apparatus configured as described above, when the release button of the camera is operated, the CPU 34 controls the aperture start magnet 19 so as to perform the aperture down to the set aperture value (the aperture value set in advance by the photographer or the camera). Energize to. When the energization is performed, the attracting force of the permanent magnet 19a is cut off, and the movement of the iron core 21 is allowed, so that the aperture start lever 18 becomes free. The aperture start lever 18 is rotated clockwise by the biasing force of the spring 22, and the bent portion 18 a pushes the interlocking portion 15 c of the locking lever 15, so that the locking lever 15 resists the biasing force of the spring 17. It rotates counterclockwise, and the latching portion 15 b is retracted from the bent portion 6 b of the drive lever 6. Accordingly, clockwise rotation of the drive lever 6 is allowed, and thereby rotation of the aperture control lever 4 in the same direction is also allowed, and the aperture control lever 4 rotates clockwise by the biasing force of the spring 7. The drive lever 6 also rotates in the same direction via the spring 8. As the aperture control lever 4 rotates, the aperture lever 3 of the lens moves in the A direction following the movement of the bending portion 4d, and the aperture starts.

As the aperture control lever 4 rotates at this time, the pinion gear 9 rotates through the sector gear portion 4a, and the ratchet wheel 14 rotates clockwise through the large gear 11 and the ratchet gear 12 integrated therewith. The rotation speed sensor 33 outputs a number of pulse signals corresponding to the rotation of the ratchet wheel 14, and the CPU 34 counts the number of pulses. When the number reaches the number calculated based on the set aperture value, the rotation is reduced. Energize the stop stop magnet 23 to stop (stop the stop). The energizing force cuts off the attracting force of the permanent magnet 23a, and the movement of the iron core 25 is allowed, so that the armature lever 26 becomes free. The armature lever 26 is rotated counterclockwise by the urging force of the spring 29, and the claw 31 b of the claw member 31 supported by the armature lever 26 is engaged with the teeth 14 b of the ratchet wheel 14 to rotate the ratchet wheel 14. Force stop. Thereby, the rotation of the aperture control lever 4 is stopped via the gears 12, 11, and 9, and the aperture stop is stopped.
After shooting, the state is returned to the state shown in FIG.

  FIG. 2 shows a moment when the claw 31b of the claw member 31 tries to engage with the ratchet teeth 14b by the counterclockwise rotation of the armature lever 26. Since the rotation speed of the ratchet wheel 14 is extremely high, the claw 31b does not immediately engage. In most cases, the tip of the claw 31b first collides with the tooth tip as shown in the figure. At this time, the claw 31b has an impact in the direction of the arrow. A force P acts. Since a moment is generated in the claw member 31 by this force P, the claw member 31 bounces clockwise against the urging force of the spring 32 and then rotates again in the engagement direction by the urging force of the spring 32. Since the rotation speed of the ratchet wheel 14 is reduced by the collision, the claw 31b usually enters between the teeth after being bound about 2 to 3 times, and is engaged. Since the ratchet wheel 14 continues to rotate even during bounding, the CPU 34 estimates the amount of rotation of the bound ratchet wheel 14 (the number of feeds of the ratchet teeth 14b), and energizes the aperture stop magnet 23 earlier by the estimated amount. As a specific estimation method, for example, a method described in Patent Document 1 may be used.

  By the way, in this embodiment, the claw 31b to be engaged with the teeth 14b is not formed directly on the armature lever 26, but is formed on the claw member 31 supported rotatably on the armature lever 26. Since the claw member 31 does not need to have an engaging portion with a magnet, the claw member 31 can be reduced in size and weight as compared with the armature lever 26. Moreover, the direction of the impact force P received by the claw 31b as shown in FIG. 2 is designed to be parallel to the line connecting the rotation centers of the claw member 31 and the armature lever 26. This means that the line of action of the force acting on the armature lever 26 via the pivot shaft 28 of the claw member 31 due to the impact force P passes through the pivot center of the armature lever 26, and therefore the armature lever 26 No moment is generated by the force P. That is, only the small claw member 31 bounces due to the collision, and the large armature lever 26 does not bounce. The light and small claw member 31 has a small moment of inertia, and by urging it with a stronger spring 32, the natural frequency when the claw member 31 bounces can be increased, and the bounce time of the claw member 31 is minimized. Can be shortened. If the bounce time is short, even if the rotational speed of the ratchet wheel 14 fluctuates due to factors such as environmental temperature, lubrication state, and part wear, there will be no significant difference in the feed amount of the ratchet teeth 14 that are bouncing, Variations can be minimized.

  Incidentally, conventionally, the armature lever is directly formed with a claw. In other words, the armature lever 26 and the claw member 31 shown in FIG. As a result, the armature lever itself will bounce. The large armature lever has a large moment of inertia, and in addition to the restriction that the armature lever cannot be urged more strongly than the attraction holding force of the magnet, its bounce time is longer than that of the claw member 31. Therefore, the variation in the amount of restriction due to the speed fluctuation of the ratchet wheel becomes significant.

4 to 6 are diagrams for explaining the difference in the variation amount, and show the experimental results by the present inventors.
FIG. 4 is a diagram showing the relationship between the elapsed time t (horizontal axis) after the diaphragm start magnet 19 is energized and the number of output pulses N (vertical axis) from the rotation speed sensor 33. As can be seen from the figure, the relationship between the elapsed time t and the pulse number N can be regarded as a quadratic curve.
N = k × T2 (k is a proportional constant)
Furthermore, √N = √k × t (1)
It becomes. That is, the square root of the number of pulses is substantially proportional to time t.

  FIG. 5 shows experimental data in which the horizontal axis represents the time (elapsed time) during which the diaphragm stop magnet 23 is energized, and the vertical axis represents the square root of the total number of output pulses until the diaphragm is locked. In the figure, D1 represents data of the present embodiment, and D2 represents data of a conventional example (in which a claw is formed directly on an armature lever). In each case, data is taken every 20 μs, and represents a situation between 15 ms and 15.7 ms in the elapsed time of FIG.

  As can be seen from FIG. 5, although there are some variations in the present embodiment, the number of pulses increases by one at the intervals of around 15.1 ms, around 15.35 ms, and around 15.6 ms, and the portion between them The waveform is almost flat. Therefore, from this waveform, it can be predicted at which point the aperture stop magnet 23 can be energized to lock the aperture with the target number of aperture stages, and if data corresponding to this waveform is stored in the camera, there will be variations. Aperture control without any effect. On the other hand, in the conventional example, variation is seen particularly in the Sc portion, and it can be seen that the flatness is lost as compared with the present embodiment. The cause of the variation is considered to be due to the aforementioned armature lever bound. From such a highly variable waveform, it is extremely difficult to accurately predict the energization timing of the aperture stop magnet 23 with respect to the target aperture stage number, and it is inevitable that the aperture amount varies.

  FIG. 6 shows the result of evaluating the data of FIG. 5 by the variation from the straight line of the above equation (1). In this embodiment, when the elapsed time is 25 ms, 20 ms, and 15 ms, the variation is 85% of the conventional technology. , 78% and 66%, respectively.

  In the above description, the armature lever 26 does not bounce, but may bounce somewhat. Therefore, the line of action of the force that the armature lever 26 receives from the claw member 31 may be slightly deviated from the rotation axis of the armature lever 26.

Next, another embodiment of the present invention will be described.
The mechanical configuration of the aperture control mechanism is basically the same as that in FIG. 1, and will be described with reference to FIG. However, the feature of this embodiment is not the mechanism but the control contents, and it can also be applied to a conventional structure in which the aperture locking pawl is directly formed on the armature lever.

  FIG. 7 shows a block diagram of the control system. The main difference from FIG. The storage device 35 stores a table in which three parameters Nap, Td, and a are associated with the number of aperture narrowing stages F. Nap indicates the number of pulses (number of output pulses of the rotation speed sensor 33) for locking the diaphragm at each number of narrowing stages, and when the cumulative number of pulses after energizing the diaphragm stop magnet 23 reaches Nap, the diaphragm is stopped. If locked, a desired number of narrowing stages is realized. However, since there is a delay time from when the diaphragm stop magnet 23 is energized to when the diaphragm is locked, it is not enough to energize the diaphragm stop magnet 23 when the cumulative number of pulses reaches Nap. Td indicates the delay time (μs). a represents a coefficient for adjustment, which will be described in detail later. All of the above values are obtained in advance by experiments and stored.

8 and 9 show the control procedure performed by the CPU 34.
FIG. 8 shows a procedure for photographing control similar to the conventional one. When a release button (not shown) is half-pressed, this program is started. In step S1, photometry is performed by the photometry device, and a photometric value is acquired. In step S2, a preset ISO sensitivity is read. In step S3, a well-known exposure calculation is performed based on the acquired photometric value and ISO sensitivity, and the aperture value and shutter speed at the time of shooting are obtained. In step S4, it is determined from the state of the release switch (not shown) whether or not the release button has been fully pressed, and when the release operation is performed, the process proceeds to step S5. In step S5, a shutter front curtain / rear curtain magnet (not shown) is energized, and then the shutter is unlocked. In step S6, mirror up is started.

  In step S7, the aperture start magnet 19 is energized to cancel the attractive force of the permanent magnet 19a. Thereby, narrowing-down is started by the mechanism described above, and the rotation speed sensor 33 generates a pulse. In step S8, the system waits for the operation time until the mirror up and narrowing operations are completed. During this standby time, the CPU 34 receives a pulse from the rotation speed sensor 33 and executes the interrupt process of FIG. 9 every time it is read. The interruption process is a process of determining the energization timing to the aperture stop magnet 23, and details thereof will be described later.

  When the operation time has elapsed, the front curtain magnet is turned off in step S9, and the front curtain is started (exposure start). In step S10, the process waits for the time corresponding to the shutter time calculated in step S to elapse. When the time elapses, the rear curtain magnet is turned off in step S11, and the rear curtain is started. When the rear curtain is closed, the exposure is completed. In step S12, the mirror is lowered, the aperture is returned to the full aperture, and the mechanical charge is performed. The process then returns to step S1.

The interrupt processing procedure will be described with reference to FIG.
As described above, this routine is started each time the CPU 34 reads a pulse from the rotation speed sensor 33, and first, the pulse number N is counted up in step S13. The value N represents the cumulative number of output pulses from the energization of the aperture start magnet 19 to the current time. In step S14, the elapsed time from energization of the aperture start magnet 19 to the current time, that is, the elapsed time until the Nth pulse output is read and stored in the variable t [n]. In step S15, the previous elapsed time t (= t [n-1]) is read from the storage device 35, and in step S16, the current elapsed time t [n] is newly stored as t in the storage device 35.

In step S17,
Tn = t [n] -t [n-1]
To obtain Tn. This Tn corresponds to the time from the previous pulse output to the current pulse output (pulse interval time). In step S18, Nap and Td corresponding to the aperture value (number of aperture stages) F obtained in step S3 are read from the table (FIG. 7) of the storage device 35. As described above, Nap is the number of pulses for locking the aperture at each aperture stage, and Td is the delay time from when the aperture stop magnet 23 is energized to when the aperture is locked.

  In step S19, it is determined whether N + Td / Tn ≧ Nap. If the result is negative, the process returns. If the result is positive, the process proceeds to step S20. Here, N is the number of output pulses up to now, and Td / Tn is the number of pulses (predicted value) generated from when the diaphragm stop magnet 23 is energized until the diaphragm is locked. When the sum of the values reaches Nap, that is, when the expression of step S19 is satisfied, the diaphragm stop magnet 23 may be energized.

  However, in actuality, if the aperture stop magnet 23 is energized when the expression of step S19 is satisfied, the aperture amount will vary. Factors that cause variations include the fact that the urging force of the diaphragm lever 3 of the lens varies depending on the lens, and the voltage applied to the diaphragm locking magnet varies depending on the remaining amount of the power battery.

Therefore, in this embodiment, in order to suppress variation, the diaphragm stop magnet 23 is energized after a predetermined delay time has elapsed after the expression of Step S19 is satisfied. Specifically, in step S20, a coefficient a corresponding to the number of narrowing stages F is read from the table, and a time (a × Tn) obtained by multiplying this a by the pulse interval time Tn obtained in step S17 is set as a delay time. In step S21, it waits until this delay time (a × Tn) elapses, and when it elapses, the diaphragm stop magnet 23 is energized in step S22. By this energization, the armature lever 3 is released from being attracted, and the diaphragm is locked as described above.
Here, a is 0 <a <1, and therefore the delay time (a × Tn) is shorter than the time during which the ratchet wheel 14 rotates by one tooth.

  FIGS. 10A to 10C show experimental data obtained by the present inventors. The difference between the target aperture stage number and the actual aperture stage number when a = 0.5 / 0.9 / 0, respectively. Represents. In either case, the applied voltage to the aperture stop magnet 23 and the urging force of the aperture lever 3 of the lens are changed in two ways, data is taken 10 times each to obtain an average value, and a standard to see the degree of variation. Deviation was determined. FIG. 10C shows a value in the conventional method in which a = 0, that is, no delay time is provided. It can be seen that when a = 0.5, the difference between the average values of the voltage and the urging force is small, and the variation is relatively small. In the conventional type (a = 0), the difference in the average value due to the change in the urging force is large, and the variation in the variation due to the change in the voltage is also large. When a = 0.9, the voltage and the urging force are most affected by the change.

  By conducting such an experiment for each number of narrowing stages, finding the optimum value of a each time and storing it in the table, it becomes possible to minimize the variation in the narrowing amount.

The figure which shows the aperture_diaphragm | restriction apparatus which concerns on one Embodiment of this invention. The figure which expands and shows the principal part of FIG. The block diagram which shows the control system of an aperture_diaphragm | restriction control apparatus. The figure which shows the relationship between elapsed time and the number of output pulses at the time of narrowing down. The figure which shows the difference of dispersion | variation with embodiment and a prior art, and is a figure which shows the experimental result by the present inventors. . The figure explaining the reduction condition of the dispersion | variation with respect to a prior art. The block diagram which shows the control system of the aperture_diaphragm | restriction control apparatus in other embodiment. The basic flowchart which shows a control procedure. The flowchart which shows the procedure of the interruption process performed at the time of narrowing down. The figure which shows the experimental result showing the effect by this embodiment.

Explanation of symbols

3 Lens Aperture Lever 4 Aperture Control Lever 14 Ratchet Wheel 14b Teeth 15 Locking Lever 18 Aperture Start Lever 19 Aperture Start Magnet 23 Aperture Stop Magnet 26 Armature Lever 27 Rotating Shaft (Claw Member)
28 Rotating shaft (armature lever)
31 Claw member 31b Claw 32 Spring for claw member biasing 33 Rotation speed sensor

Claims (7)

Rotating body that rotates with the stop of the diaphragm, and stops the rotation to stop the diaphragm,
An armature lever that is attracted and held by an electromagnetic device during the narrowing operation and starts rotating in a predetermined direction by an urging force when the attracting force is released to lock the diaphragm;
An engaging claw member that has a claw, is rotatably supported by the armature lever, and stops the rotation of the rotating body by engaging the claw with the rotating body by the rotation of the armature lever;
An aperture control device comprising: an urging member that urges the engaging claw member in a direction opposite to a direction in which the engaging claw member bounces when the claw collides with the rotating body.   2. The aperture control device according to claim 1, wherein an action line of a force that the armature lever receives from the rotation shaft of the engaging claw member at the time of the collision passes through the rotation shaft of the armature lever. . A storage device in which data for locking the aperture is stored in advance;
A control device for determining a suction release timing of the armature lever for locking the aperture stop with a target aperture step number from the data of the storage device, and releasing the suction at the determined timing; The aperture control device according to claim 1 or 2. An operation member that operates in conjunction with the narrowing of the aperture, and stops the operation to lock the aperture;
A diaphragm locking lever that starts rotating at a predetermined timing to lock the diaphragm in a predetermined narrowed state;
An engaging claw that has a claw, is rotatably supported by the diaphragm locking lever, and stops the operation member when the claw engages the operation member by the rotation of the diaphragm locking lever. Members,
An aperture control device comprising: an urging member that urges the engaging claw member in a direction opposite to a direction in which the engaging claw member bounces when the claw collides with the operation member. Rotating body that rotates with the stop of the diaphragm, and stops the rotation to stop the diaphragm,
An armature lever that is attracted and held by an electromagnetic device during the narrowing operation and starts rotating in a predetermined direction by an urging force when the attracting force is released to lock the diaphragm;
A claw that engages the rotating body by rotation of the armature lever and stops the rotation of the rotating body;
A pulse generator that outputs a number of pulses according to the amount of rotation of the rotating body;
The number of pulses output from the armature lever suction release to the stop of the diaphragm is predicted, and the sum of the predicted number of pulses and the number of output pulses from the start of rotation of the rotating body corresponds to the target throttle stage number. Signal output means for outputting a locking signal when the number of pulses is reached;
A diaphragm control device, comprising: a control device that releases suction of the armature lever after a predetermined delay time has elapsed from the output of the locking signal.   6. The aperture control apparatus according to claim 5, wherein the delay time is a time obtained by multiplying an output interval time of the pulse by a coefficient set in advance according to the target aperture stage number.   The aperture control apparatus according to claim 6, wherein the coefficient is stored in advance in a storage device.

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