JPS599211Y2 - Camera exposure time control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camera exposure time control device that compensates for exposure errors due to electrical and mechanical delays.

In general, in cameras that control the shutter using an electronic timer for counting exposure time, from the time the shutter close signal is output until the shutter actually starts closing or operating, the electricity required for the shutter control electromagnet to operate is required. Delays occur due to mechanical delays before the shutter mechanism closes the shutter, and other factors.

This delay varies from camera to camera and requires adjustment.

Further, due to the amount of overlap between the shutters, it takes time from when the shutters start operating until they open.

That is, it has a mechanical time delay.

Therefore, in order to operate the shutter, it is necessary to add a time equal to the amount of overlap between the shutters, but this amount of overlap differs from camera to camera and requires adjustment.

Therefore, in conventional cameras, these adjustments are made using a mechanical mechanism, which makes the mechanism complicated, and furthermore, it is not possible to perform sufficiently high-precision adjustments, and exposure errors are likely to occur.

The present invention was developed in view of the above-mentioned circumstances, and involves connecting a second electronic timer for counting an adjustable predetermined time to a first electronic timer for counting exposure time, and using these electronic timers to start the camera's shutter operation. It is an object of the present invention to provide an exposure time control device for a camera that can compensate for exposure errors with high precision by sequentially performing a counting operation according to the number of times and controlling a shutter control electromagnet after the counting operation is completed.

Hereinafter, the operating principle of the main parts of the present invention will be explained according to embodiments.

In Fig. 1-1, as described above, a permanent magnet 1 having magnetic poles 1N and Is (N pole and S pole) in a direction orthogonal to the rotation axis 1a is shown.
and an electromagnet 2 that applies rotational torque to the permanent magnet 1.

In the embodiment, three sets each of the permanent magnets 1 and electromagnets 2 are used, but any number of sets may be used as appropriate.

A pin 1b is implanted in the permanent magnet, and is engaged with a pin slot in an elongated hole 3b provided in a protrusion 3a of the connecting ring 3.

Since the permanent magnets 1 are thus connected by the rotatably supported connecting ring 3, the phases of the three sets of permanent magnets 1 do not shift.

There are fixing pins 4C and 40 near the protrusion 3a, which restrict the movable range of the connecting ring 3, that is, the movable range of the permanent magnet 1.

The connecting ring 3 also has another protrusion 3C.
A spring 5 whose other end is fixedly supported is hung on the connecting ring 3.
The connecting ring 3 is biased clockwise or counterclockwise depending on the angular position.

It is assumed that the coils L of the electromagnet 2 are connected in series or in parallel, and are connected to a circuit including a switch, a power source, and the like.

The circuit structure differs depending on the specific use of the rotation control device, and will be described later depending on each use, so a description thereof will be omitted here.

When no current is supplied to the coil L, the permanent magnet 1 is at a position where the connecting ring 3 connected thereto is stopped by the rotation limiting pin 4C or 40, that is, the line connecting 1N and 1S is at the illustrated position P. .

Or it is stopped at an angular position that coincides with Po.

Hereinafter, the permanent magnet 1 is initially at the illustrated position P.

The operation will be explained assuming that it is stopped at .

Eternal Shigeki 1 is P.

position and no current is supplied to coil L,
A clockwise rotational force is applied to the permanent magnet 1 by a spring 5 via a connecting ring 3.

On the other hand, the iron core 2a (7) of the electromagnet 2, the PC side 2a-1 and P.

An S pole and an N pole are respectively induced on the side 2a-2 by the permanent magnet 1, and since they attract IN and Is, a counterclockwise rotational force is generated.

Since this rotational force is larger than the clockwise rotational force by the spring 5 as will be described later, it hits the fixing pin 4C and is stopped.

Here, iron cores 2a-1 and 2a-2 are N pole and S pole, respectively.
When a current is supplied so that the poles are formed, the N pole of 2a-1 and the 1
Repulsive force with N, attractive force with 1S, and S pole of 2a-2 and 1
Due to the attractive force with N and the repulsive force with 1S, a clockwise rotational force is generated in the permanent magnet 1, and the sum of this and the rotational force of the spring 5 causes the permanent magnet 1 to rotate from the PC position to the PM position. do.

Here, PM is PC and P. This is the position at the center where the rotational force applied to the connecting ring 3 and the permanent magnet 1 by the spring 5 disappears.

If the power supply continues further, it will pass through the PM position and reach P.

It rotates toward the position, but at that time, the rotational force of the spring 5 acts in the opposite direction, and the permanent magnet 1 is rotated to overcome this force (while charging it) and hits the fixed pin 40. Stop.

If the direction of the current to electromagnet 2 is reversed at a predetermined time,
It rotates in the opposite direction as Po-+PM-+PC and returns to the original position.

When starting reverse rotation from Po, the force of the spring 5 charged during the process to PM-+Po helps the rotation, and
If the current is cut off at the position Po, it will hit the fixing pin 40 and stop at that position, similar to the case where it stops at the PC position described above.

Therefore, the timing, required time, and P of the reciprocating movement of the permanent magnet 1 and the connecting ring 3 depend on the power feeding start timing, the feeding power, and the timing of reversing the direction of the current, respectively.

The time it stays in place can be easily controlled.

The rotational speed of the permanent magnet 1 is also determined by the strength of the magnetic field generated by the electromagnet 2 consisting of a coil and an iron core, the strength of the permanent magnet 1, the strength of the spring 5, the inertia of the motion system, the frictional force, the shape of each part, etc. Needless to say.

The reason for using the spring 5 and its required specifications will now be explained.

When applying a rotation control device as described above to a small device such as a camera, the capacity of the power source, the current value, and the control device 6
It is obvious that the user is subject to restrictions such as physical size, and that the response speed to the signal current from the power supply circuit needs to be increased.

For this purpose, it is necessary to use an extremely strong permanent magnet 1 and to make the iron core 2a of the electromagnet 2 as large as possible.

However, in that case, the permanent magnet 1 is PC-+P
Although the amount of work exerted during rotation at position P certainly increases, the force that prevents rotation due to the interaction between permanent magnet 1 and iron core 2a is generated at position P.

Due to the increase in the vicinity, a disadvantage arises that if the current value is small, the permanent magnet cannot start rotating.

The biasing spring 5 compensates for this drawback. In FIG. 2, the horizontal axis shows the angular position of the permanent magnet, and the vertical axis shows the rotational force.

F1 indicates the rotational force due to electromagnetic induction between the permanent magnet 1 and the iron core 2a when the current value is O, and indicates that the rotational force is negative at the PC position, that is, the rotational force is counterclockwise.

The rotational force generated when a small current is supplied to the electromagnet 1 is F
2, the rotational force is still negative at the PC position, and rotation cannot be started.

So, for example, P like spring 5. -PM is positive, PM-
If you add an energizing mechanism that is negative in Po, a force like F3 will be added to the rotational force F2, so even if only a small current is supplied, the permanent magnet 1 will have a force P like F4.

A substantially constant positive rotational force is obtained over the entire range of -Po.

Thus, it can be seen that by using an extremely simple biasing mechanism such as the spring 5, it is possible to obtain a rotation control device that operates with a small current and has a quick response.

F 3 +F, which is the addition of the auxiliary force F3 of spring 5 to the rotational force F1
1 is P.

If you make it slightly negative at the Po position and slightly positive at the Po position, the PC position or P
.

Since the device is stopped at the same position, the power required can be reduced when this device is used in a general portable machine.

When connecting the spring 5 and the connecting ring 3, a cam mechanism is provided in the middle using a method known per se, so that the rotational force F3+F1 is P.

It is also possible to make it zero in the entire range of -Po.

It is possible to set each rotational force so that the rotational force F4 as the sum of F2 and F3 is also approximately constant over the entire range of PC-Po, and P at the Po position.

It is also possible to set the total rotational force to be larger than the position, that is, to set the inclination to be opposite to F4 shown in the figure.

Figures 1-2 and 1-3 show other embodiments of the energizing mechanism,
This indicates that it may be energized by other mechanisms.

In Figure 1-2, 6 is a permanent magnet attached to the connecting ring 3, and 7 is a permanent magnet attached to the connecting ring 3.
is a permanent magnet fixed opposite to it.

The figure shows a state at an angular position PC where the protrusion 3a of the connecting ring 3 hits the fixing pin 4C and is stopped, but the attractive force of the permanent magnets 6 and 7 is similar to the action of the spring 5. It is clear that this applies clockwise and counterclockwise biasing forces to .

1-3 shows an example using a plate spring 8, in which a protrusion 3d is provided on the connecting ring 3, and the protrusion 3d is sandwiched between the plate springs 8.

In this case, as shown in F3 in Fig. 2, the rotational force should not be brought to an equilibrium state of 0 only at the PM position, but the Po and P.

It is also possible to set it so that the auxiliary force is applied only in the vicinity of .

In the above, the load on the rotation control device is within its rotation range P.

- Although the explanation has been made assuming that Po is approximately constant over the entire range, if this is not constant or if a discontinuous load is applied, it is possible to smooth the rotation by making the force asymmetrical, adding a cam mechanism in the middle, etc. good.

In the example, the orientation of each permanent magnet is aligned and the electromagnets are arranged in a closed loop with little leakage of magnetic flux, but the orientation of each permanent magnet is intentionally shifted by a small angle, or the magnetic circuit is It becomes possible to start even with a smaller current by cutting off the current.

When connecting to a load, the Po-Po movement may be expanded or reduced as appropriate, or it may be used only within the Po-PM range.

In the above-mentioned embodiment, the output is taken out as a rotational movement of the permanent magnet 1, but this may be made into a linear movement by providing an energizing spring that is in equilibrium at approximately the center of the range of motion. .

As is clear from the above description, according to the present invention, smooth rotational control can be obtained using a weak current, so it is extremely useful when used for driving and controlling shutter blades and aperture blades of a camera.

In addition to cameras, it can also be used for rotary switches, etc.

In particular, when applied to portable machines, the consumption of power batteries can be reduced, making it economical.

Next, an example in which the rotation control device of the present invention is applied to a camera shutter mechanism will be described in detail.

In FIG. 1-1, a shutter blade 9 has two holes that fit into the rotating shaft 1a and pin 1b of the permanent magnet 1, and is opened and closed by the rotation of the permanent magnet 1.

In the embodiment, three blades are provided, each of which connects to the connecting ring 3.
Because they are connected by , the respective phases do not deviate and a substantially regular hexagonal opening is always formed.

Also, in order to simplify the structure, the rotating shaft 1a is replaced with a permanent magnet 1.
It has three blades because it is shared with the rotating shaft of
It is also possible to freely configure the connecting ring 3 to be used as a driving source to drive three or more blades or three or fewer blades.

Note that the blades 9 must be made of a non-magnetic material to prevent attraction or repulsion from occurring between the blades due to the surrounding magnetic field.

FIG. 3 is a schematic diagram of the mechanism showing only the parts that are added or changed in order to give the film an appropriate exposure amount depending on the brightness of the subject, etc. 3e is an insulating pin attached to the connecting ring 3.

S2 is a normally open contact switch, and as shown in the figure, in the Pc position, it is forcibly closed by the force F1+F3 explained in FIG.

FIG. 4-1 is a block diagram of an electrical circuit useful for controlling the electromagnetic shutter mechanism of FIG. 3 described above.

In the figure, Rpl is a light receiving element, C1 is a capacitor, and these constitute a time constant circuit.

A1 is an amplification circuit, A2 is a switch circuit, L is an electromagnetic coil, S1 is a main switch, S2 is a count start switch, E is a power supply, ■ is a shutter mechanism, and X is a switch device.

First, press the shutter button and turn the main switch S.
When the switch 1 is turned on, the switch circuit A2 operates, current is supplied to the coil L, and the shutter 2 is opened.

The switch S2 is turned off in synchronization with the opening of the shutter blades and starts counting the shutter seconds. When the charging voltage of the capacitor C1 reaches a predetermined voltage, the switch S2 is turned off through the amplifying circuit A1. is reversed, thereby reversing the direction of the current supplied to the coil L and closing the shutter.

When the shutter (2) is closed, the switch S2 is turned on. At this time, the switch device X is turned off by the switch circuit A2.

The specific structure of the block diagram shown in Figure 4-1 is shown in Figure 4-2.
This will be explained using the wiring diagram shown in the figure.

In the figure, TI, T2, T3, T4, T5, T6, T
7, T8 are transistors, R1, R2...
R12 represents a resistor, and D1 represents a diode.

In addition, Rpl is a photoconductive element, C1 is the above-mentioned timer capacitor, L is the above-mentioned coil, and S2 is the above-mentioned coil.
Using a count start switch similar to that shown in Figure 1, the timer is started by its closing->opening operation.

First, when the main switch S1 is closed by pressing the shutter button, the reference voltage of the complementary connected transistors T3 and T4 is set by the current supplied from the power supply E through the resistors R9 and RIO, and the reference voltage of the transistor T1 is set. Since the output voltage of the Schmitt circuit is set when T2 is off and T2 is on, the output circuit turns on T6 of the bridge-connected transistors T5, T6, T7, and T8.

Therefore, current is supplied to the coil L in the direction of the arrow, and the shutter blades are opened.

When the count start switch S2 is turned off in conjunction with the opening of the shutter blade, the time constant circuits Rpl, CI start counting.

When the charging voltage to the timer capacitor exceeds the inversion voltage of the Schmitt circuit after a predetermined period of time has elapsed, transistors T1 are turned on and T2 are turned off, and transistors T5 and T8 of the bridge-connected transistors are turned on. At the same time, T6 and T7 are reversed from on to off, so
A current in the opposite direction to the arrow is supplied to the coil L, thereby closing the shutter blades.

The diode DI and resistors Rll and R12 are for stabilizing the operation of the circuit.

Incidentally, by using a variable resistor as R6, photographing information such as film sensitivity can be set.

Furthermore, if RIO is used as an adjustment resistor, circuit variations can be adjusted.

Further, since a photoconductive element is used in the timer circuit, proper exposure can be automatically obtained, but if the photoconductive element is replaced with a variable resistor, manual time adjustment is also possible.

As mentioned above, according to the circuits shown in FIGS. 4-1 and 4-2 according to the present invention, the entire device is operated by operating only the main switch S1. S1 can be replaced with a non-contact switch, a reed switch, etc., and is also suitable for remote control.

Note that X1 is a transistor which prevents the start switch S2 from being closed again due to the closing of the shutter V and thereby starting counting again.

The charge stored in the capacitor C1 is transferred to the start switch S2 in conjunction with the opening of the shutter V after the main switch S1 is closed at the time of the next shutter release.
Since the battery is completely discharged by the time the battery is opened, there is no problem even during continuous shooting.

In the above embodiment, automatic exposure control can be performed by controlling the shutter speed using a separate aperture blade and a shutter blade driven and controlled by an electromagnetic rotation control device. A blade that serves as both a shutter blade and an aperture blade is provided, and it is mechanically or electrically braked to gradually open it, and a count circuit is used to reverse the current and close it at an appropriate time depending on the brightness, etc. An example will be explained.

In the present invention, this method of gradually opening the dual-purpose blade is tentatively referred to as a half-opening method.

Referring again to FIG. 3, 3f is a pin implanted in the connecting ring 3, and the elongated hole 10 of the intermediate lever 10 is rotated around the shaft 10a.
Since it is engaged with b, 3 and 10 are interlocked.

Now, when the connecting ring 3 rotates, the intermediate lever 10 swings, but since the biasing spring 5 is applied to one end 10C of the intermediate lever 10 as in the case of FIG. 1, the rotation of the device is performed smoothly. .

The other end 10d is a fan-shaped tooth. pin 11 of a sector gear of a certain governor 11 from a wheel, small gear, escape wheel, ankle return spring, etc.
When the connecting ring 3 rotates clockwise due to power supply, it gradually moves while receiving braking from the governor including the governor return spring 11b.

Therefore, the blades gradually open. When the current direction is reversed by the signal from the count circuit and the permanent magnet 1 rotates in the opposite direction, the intermediate lever 10 returns without being braked by the governor 11, so that the blade closes quickly.

After the blades are quickly closed, the gapener is returned to its original position as shown in the figure by the return spring 11b, and is in a reset state for the next operation.

At this time, it is preferable to use so-called TTL photometry in which the light receiving element is placed in the optical path behind the photographic lens, blade, etc.

Of course, as a similar mechanism is shown in Figure 10,
A structure similar to TTL photometry may be adopted in which a received light amount control device that always maintains the same F-number as the aperture F-number of the blade is provided in front of the light-receiving element.

The disadvantages of external photometry are as follows.

That is, in the first operating range, in which the operation is completed before reaching the maximum aperture determined by the photographic lens, etc., the aperture aperture changes with the shutter speed, but in the second operating range, after reaching the maximum aperture. In the operating range of , only the shutter speed changes, so some sort of switching is required for the operation of the count circuit.

As a countermeasure to this problem, there is already a known example of switching the light receiving element.

As described above with reference to FIG. 2, this electromagnetic rotation control device operates at both ends of the rotary range, namely Po and P.

Even if the power supply is cut off at a certain position, it remains in that position, which prevents wastage of power.

For example, when applied to a shutter, the operating time is several tens of seconds, and in the case of long exposure, the blades are fully open.

Cut off the power supply at the P position until the inversion signal is input.

It remains in the position and then returns to the closed state when a reversing current is supplied to the coil L, but even when the return is completed, the reversing current is automatically cut off before turning off the main switch S1. You can.

The same applies when applied to things other than shutters.

Examples will be described in detail below with reference to FIG. 5, FIG. 6-1, FIG. 6-2, FIG. 7-1, and FIG. 7-2.

FIG. 5 shows the relationship between the operation of the shutter blade that also serves as an aperture and the drive current of the electromagnetic shutter device.

The drive current is closed after the shutter is fully opened and is cut off until the start point.

This is when the main electromagnetic shutter is fully open, that is, P.

At the fully closed position, i.e., at the PC position, attraction works between the iron cores of the magnet 1 and the electromagnet 2, and the shutter blades can be maintained in the fully open or fully idle state, reducing the power consumption of the electromagnetic shutter drive power supply. You can save money.

In Figures 6-1, 6-2, and 7-1, a governor is attached to the electromagnetic shutter, and the electromagnetic shutter drive current is supplied until the shutter blade is fully opened, and after the shutter blade is fully opened, the coil current is cut off. 2 is a schematic diagram showing the structure of an electromagnetic shutter device that closes the shutter by reversing the electromagnetic shutter drive current when the shutter exposure is completed, and cuts off the supply current to the device after the shutter is closed or completed, and its electrical wiring diagram. .

In the figure, S1 is a main switch, and S4 is a switch that is turned on after the shutter blade is fully opened, and operates in conjunction with the shutter blade to short-circuit between the base and emitter of the transistor T7.

S3 is a switch that turns on when the shutter blade closes.
Short-circuit the base and emitter of transistor T8.

S5 is a power supply holding switch that is in an on state except when the shutter blade is fully closed, and S2 is a count start switch.

Assuming that main switch S1 is kept on,
The transistors T2, T4, T6, and T7 are turned on, and the transistors TI, T3, T5, and T8 are turned off, a current flows in the direction of the arrow in the coil L, and the shutter is opened.

Switch S3 is the main switch S1. It stays on immediately after you turn it on, but turns off when the shutter starts to open.

On the other hand, S2 is also turned off when the shutter starts to open, and the time constant circuit made up of Rpl and C1 operates to count the appropriate exposure time.

If the exposure time is longer than the time it takes for the electromagnetic shutter to fully open, the switch S4 is turned on after the shutter blades are fully opened, so that the base and emitter of the transistor T7 are short-circuited, thereby cutting off the electromagnetic shutter drive current.

Note that even if the electromagnetic shutter drive current is cut off, the shutter blade maintains a state where the attractive force between the magnet and the iron core of the electromagnet is fully open.

Therefore, when the proper exposure time is reached, the transistor T2
, T4, T6, T7, OFF, TI, T3, T5,
T8 is turned on, and a current flows through the coil L in the direction opposite to the arrow, thus closing the electromagnetic shutter.

Switch S is on except when the shutter blade is fully closed.
5 eliminates the need to keep the main switch S1 on as well as omitting the switch S3.

Figure 7-2 shows switch S in Figure 6-1 and Figure 7-1.
3. S4 or switch S in Figure 6-2 and Section 7-1
5, S4 is replaced with transistors T9, T10.

In the figure, delay capacitor C2 and resistor R1
It is assumed that the transistor T9 is set to be turned on immediately after the electromagnetic shutter is fully opened through a time constant circuit consisting of 3, and through a time constant circuit consisting of a delay capacitor C3 and a resistor R14. It is assumed that the transistor TIO is set to be turned on after the shutter blade is fully closed.

According to this circuit, each transistor T9, TIO
By turning on, unnecessary current flowing through the electromagnet coil can be cut off.

In addition, when using the circuit shown in Fig. 7-2, the shutter opening operation does not need to be gradually opened as shown in Fig. 5, but the drive signals are pulse signals, respectively, so that the shutter opening operation is fully opened,
It is possible to perform a fully closing operation and to have the opening or holding time controlled by a counting circuit.

The operation of the counting circuit requires correction due to various factors.

In particular, as mentioned above, when applied to a shutter, it is absolutely necessary to improve the accuracy of automatic exposure control.

The causes include mechanical delays due to inertia of moving parts, friction, etc., electromagnetic delays that occur when the magnetic circuit from the coil etc. starts energizing, or when the current is reversed. At the same time, the counting circuit starts operating, and if the closing signal, that is, the signal for reversing the coil current, is output from the RC circuit at the time when the blade should be closed, it will not work.

Hereinafter, the various factors mentioned above will be analyzed in more detail with reference to FIG.

Originally, the exposure amount is the integral of the shutter opening degree over the shutter opening time, but as shown in a, tl, t2
, t3, t4; tl, t2', t3, t4; or tl
, t3', and t4', that is, the exposure amount requires different time control depending on the shutter configuration employed.

Moreover, as a practical matter, the processes of tl and t2 are easy to control, but the processes of tl, t2', t3, t4' and t3 and t4 are left uncontrolled.

In addition, the exposure time control device is generally configured to start when the shutter begins to open at t1, but in reality, when considering the shutter as a reference, there is no delay in the exposure time control device. Similarly, the shutter start signal normally causes the shutter to start opening after a delay time.

Even when an electronic timer is used, there is a delay in the rise and fall of the coil current, so simply start the timer by tl.
, timer output inversion t3, it is not possible to perform satisfactory shutter control.

An embodiment in which the shutter according to the present invention is provided with means for relatively compensating for these delays so that the operation of the shutter can be accurately controlled will be described in detail below.

First, as an example of the compensation method, there is the following example.

In Figure 3, switch S determines when to start counting.
2 so that it opens at the desired time.

(See Fig. 8) The time to is determined by the time constant circuit, which is before the time t1 when the coil L starts energizing at the time ts, the amount of overlap of the blades 9 disappears, and the exposure starts, and closes at the time te from the time constant circuit. Time t3 when the signal is issued and the closing operation actually begins
Adjustments may be made so that the event is opened earlier than t1 by the amount of delay up to this point.

Next, another embodiment will be described.

Figures 9-1 and 9-2 show delay circuits that compensate for various delays when operating the electromagnetic shutter as shown in Figure 3 with the electromagnetic shutter control circuit as shown in Figure 4-1. This is a circuit configuration diagram with .

In the figure, S1 is the main switch, L is the coil, and R
pl is a photoconductive element, C1 is a capacitor, A1 is a Schmitt circuit, A2 is a switching circuit, D is a delay circuit, S
2' is a relay switch linked to the output of D.

Moreover, in FIG. 9-2, the relay switch S2' is replaced with a transistor T15, RD is a variable resistor, R15 is a resistor, and CD is a capacitor.

Note that TD is a transistor.

When the main switch S1 is turned on, the transistor T15 is turned on by the current flowing from the resistor R15, shorting both ends of the capacitor 01, and charging the time constant circuit consisting of Rp1 and 01 of the exposure time counting circuit. It will no longer be done.

The transistor TD connected to the time constant circuit consisting of the resistor RD and the capacitor CD turns off the transistor T15 when the operation compensation time of the electromagnetic shutter has elapsed from the time t3 when the main switch S1 is turned on, and starts counting the exposure time. Start the circuit.

The transistor TD can be used to reset the capacitor CD.

It should be noted that since the timer circuit ends its operation at the exposure time tc, it is possible to reliably synchronize the shutter closing time with t3.

Next, another embodiment of the compensation method will be described with reference to FIG.

In the figure, 12 is an aperture blade provided in front of the light receiving element Rpl.

12a is its rotation center, and 12b is its cam groove.

A pin 3h implanted in the connecting ring 3 is engaged with the cam groove 12b.

Now, when the connecting ring 3 rotates clockwise, the shutter blade 9
is opened and the aperture blade 1 of the light receiving element Rpl is opened by the pin 3h.
2 swings, and its notch 12C forms an opening to control the light irradiated onto the light receiving element Rpl.

Depending on the angular position of the connecting ring 3, the F-number of the photographing and photometry apertures formed by the shutter blade 9 and the blade 12 of the light-receiving element Rpl is determined, but both are set so that they always have the same F-number. This is equivalent to so-called TTL photometry.

However, when the blades are driven by electromagnetic force, as shown in Figure 8a, the blade actually starts to close from the time tc when the closing signal for reversing the current direction of the coil L is output from the counting circuit. Until t3, a delay such as t3-tc occurs due to coil actance, inertia of the movable part, etc., so it is necessary to issue the closing signal early.

Therefore, if the phase is shifted so that the aperture of the blade 12 always has a smaller F number (larger aperture diameter) than the aperture of the blade 9, and the opening of the photometric aperture starts first, this delay can be compensated for. Fully automatic exposure is obtained.

Counting by the counting circuit starts from the moment when the overlapping amount of the blades 12 disappears and light begins to be irradiated onto the light receiving element Rpl, but the dark resistance (resistance when no light is irradiated) of the light receiving element Rpl is ignored. If it is not as large as possible, a count start contact switch S2 shown in FIG. 3 may be provided to operate at the same time as or slightly before the light receiving element Rpl is irradiated with light.

If the light receiving element itself has a response delay, it is natural to further compensate for the delay.

In this way, any delays caused by various factors in the opening and closing of the shutter blades are compensated for.

In this case, the timer circuit is driven by manually inputting the aperture information to the photodetector, so there is no need to switch the photodetector even when the shutter device is a half-open type and is used for long exposures. can do.

Of course, there is no problem even if the shutter device is not a half-open type but an instantaneous type.

Note that it is desirable that the shutter device be of the instantaneous closing type.

As explained in FIG. 8C, if there is a delay between the time point tc when the shutter close signal is output and the time point t3 when the shutter is closed, the time point to when the start signal of the timer circuit is output and the time point when the shutter is opened. It may be advantageous to have a shutter control device that operates accurately even if t1 is the same.

FIG. 11-1 schematically shows the structure of the input circuit of this type of shutter control device. In the figure, Rp1 is the first light receiving element, which together with the capacitor C1 constitutes a time constant circuit.

RB is an adjustment resistor, and Rp2 is a second light receiving element.

When the input circuit has the above structure, the potential VQ at the point Q becomes a value depending on the brightness of the subject due to the voltage dividing circuit of the second light receiving element Rp2 and the adjustment resistor RB.

When the start switch S2 is turned off when the shutter is opened, the capacitor 01 receives the first light through the first light receiving element.
Charging is performed as shown by the dotted line in FIG. 1-2, and the time tc at which the amplifier A1 is inverted at the inversion potential 1 is given in such a manner that the delay is compensated for depending on the brightness of the subject.

That is, the time point at which the switch S2 is opened is shifted from to to t1, so that the timer is activated earlier.

Incidentally, the same function can be achieved by setting the inverting voltage of the amplifier A1 low and providing a light receiving element in the setting circuit.

The electromagnetic rotation control device of the present invention is not only useful when applied to a shutter as described above, but also can be used to drive and control an EE aperture whose aperture is controlled depending on the brightness of the subject, etc. It is valid.

First, one embodiment will be described.

Figure 12 shows the electromagnet 2 in the mechanism diagram of Figure 1-1.
Instead of using coil L, double-wound coils L1 and L
2 shows that it is constructed with two coils.

It is assumed that a drive circuit as shown in FIG. 13 is connected to the coils L1 and L2 so that currents flow in directions that cancel each other out.

The light receiving element Rp1 has a blade 9 (
In this case, the aperture blade 1 is placed behind the aperture blade (in this case, the aperture blade) and used for TTL photometry, or the aperture blade 1 is linked to the aperture blade 9 as shown in Fig. 10.
2 (in this case, the phases of 9 and 12 are matched).

The drive circuit shown in FIG. 13 will be explained below.

Light corresponding to aperture information and subject brightness information is input to the light receiving element Rpl.

If the film exposure and shutter speed are set in one or both of the variable resistors R15 and R16, the circuit resistance R17 and the amplifying transistors T16, T17, and T18 cause the coils Ll and L2 to have the above-mentioned mutual effect depending on the subject brightness. Opposing forces are generated, and the sum of these forces drives the aperture blades.

In this way, the aperture of the diaphragm driven by the sum of the coils Ll and L2 is servo-controlled to an aperture degree that corresponds to the subject.

S1 is a power switch provided to prevent battery E from being exhausted.

Next, another example of the EE aperture will be described.

As in the previous drawings, FIG. 14 omits the drawings of parts that overlap with the previous drawings, and shows a state in which the aperture diameter is approximately in the middle.

A spring 13 is added to the connecting ring 3 to forcibly rotate it counterclockwise, and the rotational force by the spring 13 is from the position PC to the position P.

It gradually increases as you move towards. The blades 9 are oriented in the opposite direction to those shown in FIGS. 1-1 and 10, and are set so that they are fully open at the position PC and are set to the minimum aperture at the position Po.

Now, when a current is applied to the coil L of the electromagnet 2 (see Figure 1-1) in the direction of rotating the permanent magnet 1 clockwise, the sum of the rotational force of the permanent magnet 1 and the rotational force of the springs 5 and 13 is The permanent magnet 1 and the connecting ring 3 stop the blade 9 at the angular position where the blades 9 are balanced.

Since the position at which the blade 9 stops is determined by the magnitude of the current value of the coil L, a circuit may be used to supply a current according to the brightness of the subject, the sensitivity of the film, the time of a separately provided shutter, etc.

Next, yet another embodiment of the EE aperture will be described.

This is done by gradually opening the aperture using a mechanism similar to that of the shutter previously explained using Figure 3, etc., controlling this with a count circuit, and then opening the shutter separately after setting the aperture value. It opens and closes the blades.

In FIG. 15, 14 is a release lever, which is supported by a guide pin so as to be movable up and down as shown in the figure.
A return spring 15 is attached.

Reference numeral 16 denotes a lock pawl, to which a spring 17 is attached which always applies a rotational force in the horizontal direction.

Reference numeral 18 denotes a shutter blade drive ring, which is charged in conjunction with film winding and is operated by pressing down the release lever 14. Since a normal shutter may be used, a detailed description thereof will be omitted.

Now move the release lever 14 to the first position against the return spring 15.
Press down to the position.

The normally closed main switch S1, which had been opened by the insulating pin 14a installed in the insulating pin 14a, is closed, and the aperture device having the structure shown in FIG. 3 starts operating by the electromagnetic rotation control device. .

Since a governor such as 11 is attached to the diaphragm device, the diaphragm aperture continues to open at a predetermined speed.

At this time, as in the case of the shutter, the count start switch S2 opens at a predetermined time and the count circuit starts counting.

The first setting depends on factors such as the brightness of the subject, the sensitivity of the film used, and the shutter speed that has already been adjusted manually.
By means of a circuit as shown in Figure 6, the power supply to the coil is cut off at a desired time, and the aperture value at that time is maintained.

When the aperture setting is completed, the lamp W goes out, so after confirming this, push down the release lever 14 further.

When pressed down to the second position, the shutter is released by a mechanism not shown, the shutter blade drive ring 18 rotates clockwise, and the normally open reset switch S6 is opened.

After the predetermined time has elapsed, the switch 18 returns to the position shown in the figure and the switch S6 is closed again.

When the switch S6 is closed, this signal causes a current to flow through the coil in the direction of restoring the diaphragm, and the diaphragm returns to its pre-use condition, for example the closed condition.

The timing to return the release lever, that is, the timing to release the release lever, is often a problem in the case of shutters that can perform long exposures, but in this embodiment, as shown in FIG. 16, a self-holding circuit is used. , so you can release the shutter immediately after it starts operating.

However, if you push it down enough, or if you push it down halfway between the first and second positions and release your hand, a problem will occur.

That is, the diaphragm device, once set, does not return even though the release lever 14 has returned, resulting in a malfunction in the next photograph.

Therefore, in this embodiment, the simplest and most reliable example will be shown.

Although the lock pawl 16 does not engage with the locking portion 14b of the release lever 14 in the illustrated position, it engages at or just before the first position, and thereafter prevents the release lever 14 from returning.

When pressed further down, the engagement is released at or immediately after the second position, allowing the release lever 14 to return to its original position.

As a precaution for use, as mentioned above, from the 1st position to the 2nd position
The diaphragm is set while the button is pressed down to the second position, and this takes several milliseconds, so the button must be pressed down slowly to reach the second position after the lamp W goes out, but in order to make this even more reliable, It is also possible to attach a governor to the release lever 14 so that it cannot be pressed suddenly.

In addition, when the shutter and the ring 18 are driven and controlled by an electromagnetic rotation control device, a delay circuit is provided so that the shutter is turned on a predetermined time after the aperture setting main switch S1 is turned on. It can also be used to delay.

Next, an example of an aperture control circuit applicable to the above-described embodiment in FIG. 15 will be described in detail with reference to FIG. 16.

First, when the power switch S1 is turned on, charging of the capacitor C1 from the battery through the light receiving element Rpl, which constitutes a time constant circuit, is started by turning off the start switch S2. After a predetermined period of time, the output level is reversed to another output level.

The output of amplifier A1 is complementarily connected to transistor T3.
, T4 is turned on.

Resistors R7, R8, R9 and RIO determine the operating levels of transistors T3 and T4 as necessary and stabilize their operations.

The output of transistors T3 and T4 is the transistor T5
, T6, respectively.

The output circuits of the transistors T5 and T6 are bridge-connected together with the output circuits of the transistors T7 and T8 as in the previous case, and the coil L serving as a common load is connected between the detection terminals of the bridge circuit.

W is a lamp connected in parallel to the emitter-collector circuit of transistor T5, and this lamp W is turned on when transistors T7 and T6 are turned on, current flows in the direction of the arrow in coil L, and the diaphragm is closed. to warn you when the aperture is being set.

On the other hand, when the power switch S1 is turned on, charging of the capacitor C4, which forms a delay circuit together with the resistor R20, from the battery E is started, and its output is sent to the coil Lh for holding the switch S5 in parallel with the main switch S1. a bistable multi-pibrator M2 with its output as well as T7, T of said bridge-connected transistors;
8, respectively, are manually powered by a bistable multi-pibrator M1 whose output is a signal for controlling the ON and OFF states.

When the output of A1 is applied to the coil L together with the output of M1, first the transistors T5 are turned off, T6 is turned on, T is turned on,
T8 turns off.

When C1 is charged with a predetermined charge, the transistor T5 turns on and T6 turns off, but T7 and T8 turn on and off, respectively.
It remains off.

The current flowing through T5 and T7 therefore causes coil L to stop the diaphragm in the set position.

A switch S6 that is opened in conjunction with the shutter that is opened after at least the time required for aperture has elapsed since S1 was turned on.
The transistor T19 is turned from on to off via the resistor R19, and then, after a predetermined time, the transistor T19 is turned from off to on again by the switch S6, which is closed following the closing of the shutter.

Since the bistable multi-bibreak M1 is configured such that its output is inverted when the transistor T19 is again inverted from OFF to ON in this case,
This turns the transistors T7 and T8 from on and off to off and on, respectively, and causes a current to flow in the direction opposite to the direction of the arrow in the coil L, thereby instantaneously setting the aperture to the open state.

To briefly add to the resetting of the holding circuit of the power switch S1, suppose that the switch S3, which is opened in conjunction with the setting of the aperture, is closed in conjunction with the above-mentioned reset of the aperture. , the bistable multi-pibrator M2 is turned on when the switch S3 is on and the power switch S1 is turned on.
When turned on, first the switch S5 is turned on via the coil Lh.
is held on and continues to hold that state even when S3 is turned off as described above, and then S3 is turned on (S3
(is reset) and as a result, the switch S5 is reset to ON via the coil Lh.

Fig. 17-1, Fig. 17-2, Fig. 18, and Fig. 19 show still another use of the electromagnetic rotation control device of the present invention, that is, when it is used as a preset aperture device for a single-lens reflex camera, etc. I will explain about it.

First, in Figure 17-1, 19 is a preset ring.
It has a cam surface 19a.

20 is an intermediate lever which rotates around 20a, has a pin 20b at one end that engages with the long hole 31 of the connecting ring 3, and has a cam surface 19a at the other end to control the rotation angle of the intermediate lever 20. A pin 20C for regulating is implanted.

When the camera is not used, it is assumed that the blades 9 and the like are stopped at the position shown in the figure.

Now, when the camera's shutter button is pressed, the electric circuit is switched on and the permanent magnet 1 rotates clockwise.
The blades 9, which had been in the fully open position until then, are narrowed down, and the intermediate lever 20
Since the rotation stop position of the blade 9 is regulated, the aperture value of the blade 9 becomes the set value.

When the exposure is completed, for example, the circuit is switched by a signal indicating that the film travel after the four-force plane shutter is completed, and the coil L
When the current is reversed, the permanent magnet 1 rotates counterclockwise and returns to its initial position as shown.

As mentioned above, when you release your hand from the shutter button, the circuit is switched off and the blades remain fully open.

Next, the preset aperture device shown in FIG. 17-2 will be explained.

As mentioned above, the illustrated example shows that the electromagnetic rotation control device of the present invention is P
At the c and Po positions, by utilizing the characteristic that they are held in those positions even if the coil current is cut off, unnecessary This prevents wastage of power by minimizing energizing time.

The auxiliary ring 21 is energized clockwise, and the connecting ring 3
Attach a weak spring 22 that rotates following the rotation.

The intermediate lever 20 is interlocked with the auxiliary ring 21, and this is regulated by the set position of the preset ring 19, as in the case of the previous example.

Further, the aperture blades 23 are driven by the auxiliary ring 21.

Now, when the coil is energized for a predetermined period of time, the connecting ring 3 rotates to the Po position, and thereafter remains at the PO position even if the current is cut off.

At this time, the auxiliary ring 21 rotates following the connecting ring 3 by the spring 22, but at this time, the pin 20C is rotated by the cam surface 19a.
The diaphragm blades 23 remain in pressure contact with the aperture having the desired opening diameter.

Exposure is then carried out by the shutter and, as in the previous case, a current is sent in the coil in the opposite direction and the connecting ring 3 pushes against the auxiliary ring 21, so that the device returns again to the initial state shown.

In order to cut off the current at the Po position or the Pc position, contact switches such as those shown at S3 to S5 in FIGS. 6-1 and 6-2 may be provided and operated by the connecting ring 3, for example.

FIG. 18 is a circuit connection diagram that is effective when applying FIGS. 17-1 and 17-2.

The difference from FIG. 16 is that bridge-connected transistors T5, T6, T7, and T8 are used as an instantaneous switch circuit to provide a preset aperture.

For this purpose, both output terminals of the bistable multivibrator M1 were used.

Note that the switch S4 is not necessary in FIG. 17-1 since it can be left open, but it is closed in FIG. 17-2 to reduce power consumption.

In particular, in order to avoid delays in the operation of the preset diaphragm device as much as possible, Fig. 19 shows that the high instantaneous starting power supplied to the coil L is instantaneously supplemented via a DC booster circuit, and the diaphragm operation of the preset diaphragm device is instantaneously performed. It was designed to allow

In the figure, a circuit Th surrounded by a dotted line is a DC booster circuit, in which a double-wave rectifier circuit is connected to an oscillation circuit including an oscillation transistor T20 via a transformer.

In the figure, transistors T5' T6, T7, T8
It is assumed that the control human power and drive input are configured in the same manner as shown in FIG. 18.

A boost switch S7 that is closed before the aperture is driven from the power source E;
The charge charged in the high voltage capacitor C5 via the booster circuit Th is discharged through transistors T7 and T6 which are turned on by turning on the main switch S1 (not shown), and the current flowing through the coil L in the direction of the arrow becomes a large current.

In this way, the aperture blades are instantaneously narrowed down.

Diode D2 is a unidirectional switching element for preventing direct charging of capacitor C5 from power source E.

D3 is a protection diode for preventing high voltage from being reversely applied to the load circuit.

In a camera to which the electromagnetic rotation control device of the present invention is applied, it is used in general cameras to enable automatic exposure control during artificial light photography, that is, automatic flash photography. Just use the method.

The method differs depending on the type of artificial light used, whether the shutter blades and diaphragm blades are separate, or if they are used as blades, but some examples will be described below.

When using a flash bulb, the shutter time should be constant (for example, y seconds), the ignition contact of the bulb should be set to M or ), etc., is the usual method.

In order to keep the seconds constant, there are methods such as switching the light receiving element of the counting circuit to a fixed resistor.

To control the aperture value, for example, use the aperture ring 1 in Fig. 17-1.
9 may be displaced depending on the distance, guide number, etc.

The same applies to the case where a mechanism as shown in FIG. 3, which serves both as a shutter blade and an aperture blade, is used.

When using a flash discharge tube device, it is possible to use the synchro contact as an Even if the aperture is emitted at a certain moment, the same result will be obtained as if the aperture diameter had been maintained at that moment.

That is, the dual-purpose blade is driven by a rotation control device that is set at a constant speed by a governor, and the light receiving element is switched to a variable resistor adjusted by distance, guide number, etc., and when the desired aperture diameter is reached, the circuit is activated. It is also possible that the trigger circuit of the flash device is activated to emit a flash, and at the same time the current in the coil is reversed to close the blades.

Of course, the coil current may be designed so that it is always reversed after the blades are fully opened, or the trigger operation timing may be controlled by each element.

As described in detail above, according to the present invention, an adjustable second electronic timer for counting a predetermined time is connected to a first electronic timer for counting exposure time, and these electronic timers are used to start the shutter operation of the camera. By sequentially counting according to the number of shutters and controlling the shutter control electromagnet after the counting operation is completed, various delays such as time delay due to the amount of shutter overlap, mechanical delay, electrical delay, etc. can be easily adjusted. Accordingly, it is possible to provide an exposure time control device for a camera that has effects such as being able to compensate for exposure errors with high precision.

[Brief explanation of drawings]

FIG. 1-1 is a mechanical schematic diagram illustrating the structure of the main parts of the present invention, and FIGS. 1-2 and 1-3 are modifications of the main parts. Figure 2 is an explanatory diagram showing the rotational force acting on the permanent magnet at each operating position, Figure 3 is a schematic diagram of the main part of the present invention, that is, the mechanism when the rotation control device is applied to a camera shutter, and Figure 4-1.
4-2 shows a specific example of the shutter circuit. Figure 5 is an explanatory diagram showing the shutter opening or diaphragm opening versus time obtained when, for example, an opening/closing contact is provided in the mechanism in order to prevent power consumption, and the amount of power supplied to the coil at that time. FIG. 3 is an explanatory diagram showing a pattern in which the current is interrupted midway. Figures 6-1 and 6-2 are schematic diagrams of the configuration of a power-saving embodiment, Figure 7-1 is a circuit connection diagram of the power-saving embodiment, and Figure 7-2 is a circuit diagram of the power-saving embodiment. FIG. 3 is a circuit connection diagram when the switching contacts are non-contact. Figure 8 is an explanatory diagram for understanding what is required for complete synchronization of the shutter opening and the timer circuit, and Figure 9-
1 and 9-2 are wiring diagrams in which the delay in shutter opening is offset by the delay in the timer circuit. Figure 10 shows that by inputting aperture information to the light receiving element,
This is a schematic diagram of the structure when it is effective for a half-open shutter, and the feature is that shutter control is performed accurately with a single light receiving element, and it is advantageous to use a light receiving diode or the like as the light receiving element. 11-1 and 11-2 are circuit connection diagrams in the case where a plurality of light receiving elements are used and a timer circuit is used to compensate for the delay in closing the shutter. FIG. 12 is a schematic diagram of the structure of a multi-turn coil for driving an aperture, FIG. 13 is a schematic diagram of a circuit when the rotation control device of the present invention is applied to aperture control, and FIG. 14 is a schematic diagram of the same structure. FIG. 15 is a schematic diagram of the structure of another diaphragm control device, and FIG. 16 is a circuit diagram suitable for this. Figures 17-1 and 17-2 are schematic diagrams of the configuration of the preset aperture device, Figure 18 is a circuit connection diagram suitable for these, and Figure 19 is particularly designed to allow the preset aperture device to instantaneously narrow down the aperture. The coil is additionally driven by the discharge current from the capacitor charged by the booster circuit.

Claims (1)

[Scope of utility model registration request] A second electronic timer for counting an adjustable predetermined time is connected to the first electronic timer for counting the exposure time, and one of the first and second electronic timers is operated to count at the same time as the camera shutter starts operating. After the counting operation of one electronic timer ends, the counting operation of the other electronic timer is started, and after the counting operation of the other electronic timer ends, the shutter control electromagnet can be controlled by the counting operation end signal. . An exposure time control device for a camera, characterized in that the time counted by the second electronic timer is made equal to a shutter operation compensation time, which differs from camera to camera, such as mechanical delay, to compensate for exposure errors.