JPH06102558A - Diaphragm controller - Google Patents

Abstract

PURPOSE:To enable a user to be given a chance for photographing again by warning and instructing the user if the actually driven quantity and the quantity required to be driven are not same. CONSTITUTION:The number of times N0 of the output level change of an output port P5 at the time of a stopping down mode and the number of times N1 of the output level change of the output port P5 at the time of a full-aperture mode are N0=N1 when a motor responds to step pulses. Whereas, N0not equal to N1 is attained if the motor fails to be started or by not responding the step pulses or the diaphragm fails to operate up to a desired diaphragm aperture. The numbers N0, N1 of times of the output level changes are compared. An H is outputted to an output port P7 to trigger a light emitting LED to emit light and to output the warning of the abnormality in diaphragm operation in case of N0not equal to N1. Namely, the abnormality of the diaphragm operation is detected by comparing the number of the step pulses at the time of driving to the stopping down side from the full-aperture and the number of the step pulses at the time of driving from the stopping down to the initial position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aperture control device driven by a step motor.

[0002]

2. Description of the Related Art Conventionally, an aperture control device for controlling an aperture using a step motor is known. In such an aperture control device, if the pulse corresponding to the number of control stages of the aperture is supplied to the step motor, the aperture can be set to an arbitrary aperture, and the control is simplified. Further, by providing the open state confirmation switch, it is possible to determine the initial position of the diaphragm and obtain an accurate drive amount from the open state.

[0003]

However, in the above-mentioned conventional example, since the open state is confirmed and the control is performed by feeding back only whether or not the aperture is in the open state, the aperture actually moves up to the original aperture diameter. It is undetectable. Therefore, even if there is a situation where the actual driving amount decreases due to the external motor etc. not responding to the pulse given by the step motor, this cannot be detected,
As a result, it was recognized that the user was able to take the picture normally even though the accurate exposure could not be obtained,
You will not be given the opportunity to start over.

An object of the present invention is to provide an aperture control device that solves the above problems.

[0005]

SUMMARY OF THE INVENTION The aperture control device according to the present invention gives a user a warning instruction when the amount actually driven and the amount to be driven are different from each other so as to give the user a chance to restart the photographing. It is characterized in that it is configured. More specifically, the improved aperture control device of the present invention comprises means for comparing the number of step pulses when driven from the initial state in the aperture direction with the number of step pulses when driven from the aperture state to the initial position. By providing a means for giving a warning of abnormal diaphragm operation in accordance with the comparison result, it is configured to issue a warning of abnormal diaphragm operation to the user.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an exploded perspective view of an electromagnetically driven diaphragm device according to the present invention. Reference numeral 1 denotes a ring-shaped base plate, which has an opening through which photographing light passes in the center. A bearing 1a is provided on a part of the base plate 1. Reference numeral 2 denotes a rotor shaft arranged in parallel with an optical axis passing through the center of the lens barrel. A rotor magnet 3 is fixed to the shaft 2 and is axially supported by the bearing 1a, while a pinion gear 4 is coupled to the tip thereof. Has been done. The other side of the rotor shaft 2 is fitted to a bearing 5a provided on a fan-shaped bearing plate 5, and rotatably supports the rotor magnet 3. It is assumed that the rotor magnet 3 is made of, for example, a plastic magnet, and the outer periphery thereof is divided and alternately magnetized, and is anisotropically arranged. Reference numerals 6 and 7 denote stators, and each stator has several fork-shaped pole teeth 6a and 7a, and the two stators are shown separated in the figure. It's supposed to be inside. Further, the pole teeth 6a and 7a are arranged along an arc so as to keep an equal distance from the surface of the rotor 3. It should be noted that the other stators 8 and 9 provided to face each other with the rotor 3 interposed therebetween have the same form.

Therefore, the magnetic fringes of the rotor 3 face the pole teeth 6a-9a of 6-9, respectively. Reference numerals 10 and 11 are iron cores arranged in parallel with the optical axis, and coils 12, 13 are wound around the outer circumferences. Further, one end of the iron core 10 is crimped to the hole 5b of the bearing plate 5 through the hole 7b of the stator 7. Similarly, the other end of the iron core 10 is connected to the main plate hole 1b through the hole 6b of the stator 6.
Has been crimped by. Similarly, another iron core 11 is also caulked to the hole 5c of the bearing plate 5 and the hole 1c of the main plate 1 through the holes 8b and 9b of the stators 8 and 9, respectively. Even if these iron cores are arranged in the optical axis direction, the diameter is such that the iron cores are not magnetically saturated.

On the other hand, the arcuate portion of the flexible printed board 18 is adhered to the main plate 1, and the connecting wire 1 of the coil is attached to the contact.
2a and 13a are soldered. A substrate 14 having a conductive pattern 14a formed thereon is fixed to the base plate 1, and lead wires 14b from the conductive pattern 14a are soldered to the contacts of the flexible printed board 18. Further, the board 14 is provided with a screw hole,
Since the screw 14c is screwed and fixed through the elongated hole 1e provided in the base plate 1, the position of the substrate 14 can be adjusted as necessary. That is, after the diaphragm device is completed by the screw 14c, the switching timing of the opening switch can be adjusted from the outside.

Next, the arrangement of the diaphragm device will be described. A plurality of well-known diaphragm cam grooves 15a are cut in the annular cam plate 15, and dowels 16a of each diaphragm blade 16 are fitted therein.
On the other hand, the rear surface dowel 16b of the diaphragm blade 16 has a plurality of holes 17a formed in a rotating ring 17 which rotates around the optical axis.
Are fitted to each other. The rotating ring 17 has an outer peripheral surface 17
b is fitted on the inner peripheral surface of the separating projections 15b provided at four positions on the cam plate 15, and is rotatable with respect to the cam plate 15. Reference numeral 17c is a rack formed on the outer peripheral surface of the rotary ring 17, and the rack 17c is engaged with the pinion gear 4. It should be noted that the rotary ring 17 may be provided with an arcuate slit, and a rack may be cut on the outer peripheral edge of the slit. Reference numeral 17d is a brush corresponding to the pattern 14a of the substrate 14 and is fixed to a part 17e of the rotating ring 17. Reference numeral 19 is a screw for connecting the cam plate 15 and the base plate 1, which is a convex portion 15b of the cam plate 15.
The cam plates 15 are fixed to the main plate 1 by being inserted into the long holes 15c (four holes at the same number) formed in the base plate 15e and screwed into the tap holes 1d of the main plate 1. Cam plate 15
A rotating ring 17 is rotatably housed in a space formed between the base plate 1 and the cam plate 15 by the convex portions 15b and 15e of the rotating ring 17, and the rotating ring 17 is rotatable on the inner peripheral surface of the convex portion 15b. Supported by. Cam plate 15 by the long hole 15c
Can adjust the fixed position with respect to the main plate 1 about the optical axis, and adjusts the aperture diameter to the reference value. The portion 17e to which the brush 17d is attached is the convex portion 15 of the cam plate 15.
The rotation of the rotary ring 17 is restricted so as to face one of the d. Further, the rotation limitation in the opposite direction is performed by the rack end surface 17f provided on the outer circumference of the ring 17 and the convex portion 15e.

Next, the operation of the electromagnetically driven diaphragm device shown in FIG. 1 will be described with reference to FIGS. Figure 2
(A) to (d) are rotor magnets 3 and stators 6 to 9
It is the figure which showed the positional relationship with. FIG. 2A shows a state in which the coils 12 and 13 are not energized. In such a state, the poles of the rotor magnet form a magnetic path through the stator, so that the poles of the rotor magnet 3 face the stators 6 and 7 and are stopped. At this time, it is assumed that the stators 8 and 9 and the rotor magnet 3 are stopped by being displaced by a half pitch (= 1 / 2P) that does not face the poles.

In order to have this positional relationship, the stators 6 and 7 and the stators 8 and 9 are arranged so as to be displaced by 1 / 2P, and when expressed by the equation, θ = nP + 1 / 2P.

P in FIG. 2A is a magnetizing pitch of the magnet, which is made to coincide with the pitch of the stators 6, 7 or 8, 9.

The state of FIG. 2B is a diagram when the coil 12 is energized in the reverse direction (↑ direction) and the coil 13 is energized in the forward direction (↓ direction), and the respective states are B and A. Similarly, the following description will be made assuming that the coil 12 is energized in the positive direction B and the coil 13 is energized in the reverse direction as A.

When the coil 12 is energized with B, N is generated in the stator 6 and S is generated in the stator 7, and similarly, when the coil 13 is energized with A, N is generated in the stator 8 and S is generated in the stator 9. For this reason, the respective poles magnetized in advance on the outer circumference of the rotor 3 and the poles generated on the respective stator pole teeth repel or attract each other, and the rotor 3 rotates counterclockwise. At this time, the stators 6 and 7 and the stators 8 and 9 are displaced from each other by 1/2 pitch, and the poles of the rotor try to maintain balance while facing the stators 6, 7, 8 and 9. That is, when the energization as shown in FIG. 2B is performed, the rotor 3 moves counterclockwise by 1/4 pitch with respect to FIG. Next, suppose that the power supply shown in FIG. In this case coil 1
2 is turned off and only coil 13 is energized with A. At this time, an N pole is generated in the stator 8 and an S pole is generated in the stator 9, so that they are attracted to the poles of the rotor 3 and further rotate in a 1/4 pitch counterclockwise direction with respect to FIG. FIG. 2D is a diagram when the coil 12 is energized with B and the coil 13 is energized with A. Since the principle is the same as in FIGS. 2B to 2C, the operation description is omitted.

Based on the operation principle as described above, FIG. 3 shows a timing chart of coil energization. The horizontal axis of FIG. 3 is the number of pulses (or time), and the vertical axis is energization ON or O.
The FF is shown, and the timing chart shows the states of the energizing directions A, B, A, and B, and the bottom of FIG.
(B), FIG. 2 (c), and FIG. 2 (d) are shown in correspondence with the states. The state of the combination of A, B, A and B is shown in FIG. 3, and eight combinations BA to B are possible. One combination at this time is counted as one pulse. That is, after the 9th pulse, the rotor 3 can be rotated up to an arbitrary angle by energizing the first pulse for the phase.

A state in which the diaphragm moves by using a stepping motor based on this principle as a drive source will be described with reference to FIG. First, when the rotor 3 rotates, the pinion gear 4 rotates, and further, the rotating ring 17 rotates about the optical axis.

Here, the pinion gear 4 and the latch 17c constitute a speed reducing mechanism, and the rotating ring 17 can be rotated sufficiently even if the torque of the rotor 3 is relatively small. The blades 16 having the dowels 16b fitted in the holes 17a of the rotary ring 17 move relative to the fixed cam plate 15, so that the tips of the aperture blades 16 move in the radial direction. These operations are the same as those of the conventional mechanical diaphragm, and therefore will be omitted. Rotating ring 17
With respect to the rotation angle, the rotor 3 rotates at equal intervals, and thus the rotation angle is constant. Therefore, by adjusting the shape of the cam groove 15a of the cam plate 15, the rotation angle of the rotary plate and the number of diaphragm steps can be matched. Specifically, the relationship is set so that the aperture diameter changes by 1/8 step when the rotor 3 advances one step. That is, when the rotor is driven by 8 steps, the diaphragm changes by one step.

FIG. 4 is a block diagram showing a photometry system of a camera from the photometry to the stop of the aperture. The light quantity measured by the photometry circuit 20 of the camera is calculated in a known manner in consideration of factors such as film sensitivity, shutter speed, and aperture value, and the number of aperture steps is determined. This is performed by the light amount setting circuit 21. The number of diaphragm steps is converted by the clock circuit 22 and the distribution circuit 23 into the number of driving steps of the step motor. By determining which of the coils 12 and 13 is energized by the step motor driver circuit 24 according to the number of steps, the step motor can be rotated by an arbitrary amount. That is, it becomes possible to match the specified aperture diameter. When returning the diaphragm blades, the rotor 3 rotates clockwise and can be returned to the open state by performing the operation described in FIG. 2 in reverse. Reference numeral 25 is a shutter drive circuit, which is a light amount setting circuit 2
It is controlled based on the output of 1.

On the other hand, the substrate 14 and the brush 17d constitute a switch that is off when the diaphragm is open and on when the diaphragm is small. Since this switch has a structure in which the camera performs open metering, it is necessary to determine whether or not the camera is in the open state. For example, when the blade moves to the small aperture side due to an external impact or the like, the photometry is prohibited, and the function of performing the photometry again after returning the aperture blade is performed.

FIG. 5 is a diagram showing the relationship between the stop position of the 1-2 phase drive motor described in FIG. 2 and the aperture diameter. The aperture open diameter is the lathe aperture (the opening of the aperture plate penetrating the main plate 1 of the aperture device. It is a type determined by (diameter). The white circle position is a stable position that can be stopped without energizing the step motor, that is, 1
The phase energization position and the black circle position are positions where the two coils are energized simultaneously and stopped. Is a position where the diaphragm is in the open state and is waiting, is a lathe diameter that determines the opening diameter, is a position where the open state confirmation switch (switch composed of the substrate 14 and the brush 17) is switched, and can be switched between Range, indicates a mechanical stopper position.
The interval between and is set to correspond to 1/8 step of the aperture.

Further, the reason why the possible range is provided for the switching position of the open state confirmation switch is that it is difficult to accurately position the brush position and the substrate position, and therefore the adjustment is facilitated.

FIG. 6 is a circuit diagram showing an embodiment of the distribution circuit 23 and the driver circuit 24 shown in FIG. In FIG. 6, reference numeral 101 is a microcomputer, which has input ports P1 and P2 and output ports P3 to P7. The input port P1 is connected to the open switch. The output port P3 is a port for outputting a reset pulse, and outputs a reset pulse when the power switch is turned on or when the open switch is turned off. The output port P4 is a motor rotation direction control port, P5 is a step pulse output port, and P6 is an energization control port. Reference numeral 100 denotes a light emitting LED for notifying a user of a warning of abnormal diaphragm operation, which is connected to the output port P7. Reference numeral 102 is an inverter, and 103 and 104 are NOR gates. These inverters and NOR gates send the step pulse from the NOR gate 104 in the narrowing mode, and also send the step pulse from the NOR gate 103 in the open mode. Reference numerals 105 to 107 are D-type flip-flops that form a binary counter. 1
Reference numerals 12 to 114 are AND gates and 108 to 110 are NOR gates. These gates supply clock pulses to the binary counter in synchronization with the step pulse from the NOR gate 104 in the narrowing down mode to up-count the binary counter. Further, in the open mode, a switching gate for down-counting the binary counter in synchronization with the step pulse from the NOR gate 103 is configured. Reference numerals 115 to 122 are AND gates that constitute a decoder, and select a high level signal (hereinafter referred to as H) sequentially from the AND gate 115 toward the AND gate 122 each time the count value of the binary counter changes from 0 to 7. Output. Also,
The input port P2 is connected to the output of the gate 115 and sends H when the count value is 0 to the microcomputer 101. 123 to 126 are OR gates, and the gate 123 has a count value of the above binary counter of 5 to 7
At the time of, the gate 124 outputs a count value of 1 to 3
H is output at the time of, and the count value of the gate 125 is 3 to 5
H is output at the time of, and the count value of the gate 126 is 0,
When the value is 1 or 7, H is output. Reference numerals 128 to 131 denote AND gates having one input connected to the output port P6 and the other input connected to the outputs of the gates 123 to 126, respectively. The counter value and the output states of the gates 123 to 126 are as shown in FIG.

132-135 are inverters, 136-
139 is a drive transistor for the coil 13, 140
Reference numerals 143 to 143 denote drive transistors for the coil 12.

In the AND gates 128 to 131, the inverters 132 to 135, and the transistors 136 to 143, the currents shown in FIG. 8 flow through the coils 12 and 13 in relation to the counter value. FIG. 8 has the same relationship as the energized state to the coils 12 and 13 in FIG. 3, and from these relationships, the motor rotates by one step each time the count value increases and the diaphragm shifts to the 1 / 8-step narrowing side, and Every time the count value is decreased, the aperture is rotated one step at a time in the opposite direction to the up direction, and the aperture is shifted to the 1 / 8-step open side.

Next, the operation of the motor and diaphragm shown in FIGS. 6 and 1 will be described.

The microcomputer 101 is shown in FIG.
The program shown in FIG.

Now, when the power is turned on, the computer 1
01 operates, and the flow of FIG. 9 shifts to step 1, and thereafter steps are sequentially advanced.

Step 1: Output L from the output port P7. Step 2: Output H from the output port P6. Step 3: Output a low level (hereinafter referred to as L) from the output port P3. Step 4: Output L from the output port P4. Step 5: Output H from the output port P5. Step 6: Wait for the T0 time to elapse. Step 7: Output H from the output port P3.

In the above step, the output port P3 sends out a negative pulse for a certain period of time T0, which resets the binary counter. Now the counter value is 0
The coil 13 is energized in the direction A and the diaphragm is stopped at the position shown in FIG. That is, the position of FIG. 5 is set to a phase in which the coil 13 is energized in the A direction.

Step 8: Output L from the output port P5. Step 9: Wait for elapse of a predetermined time T1. Step 10: Output H from the output port P5. Step 11: Wait for elapse of a predetermined time T2. By repeating steps 8 to 11 above, output port P3
To send a step pulse. Incidentally, the above step 3
Since L is output from the output port P4 at, the gate 104 is selected, and the step pulse is counted by the counter via the gate 104.
Therefore, the mode becomes the narrowing down mode, and the count value of the counter is up-counted. When the counter is counting up, the energization state of the coils 12 and 13 changes as shown in FIG. 8, so that the diaphragms are narrowed down by 1/8 step in the narrowing direction.

Step 12: It is detected whether or not the output level change (L → H) of the output port P5 has occurred N0 times, and when it is less than N0 times, steps 8 to 11 are repeated until the level change of the output port P5 is made N0 times. Execute repeatedly. In addition,
N0 times is determined according to the aperture step number information obtained by the light amount setting circuit 21.

Since the 1/8 step control is performed per step as described above, the relationship with the aperture step number information ΔAV obtained by the light amount setting circuit 21 is N0 = 8 × ΔAV + 2.

Therefore, for example, when ΔAV obtained by the light amount setting circuit 21 is 1, that is, when the aperture is narrowed down by one step, N0 = 10, and the aperture moves to a position 10 steps in advance from FIG. The position is 8 from the open position
It is a position advanced by one step, and this means that it has been narrowed down by one step.

When the output level change of the port P5 is detected N0 times in the above step 12 and the aperture is narrowed down to a desired aperture, the step proceeds to 13.

Step 13: Wait for elapse of time T3 Step 14: Output L from output port P6. When L is output from the output port P6, the gates 128 to 131
To L, which stops the energization of the motor.

After the aperture is narrowed down in steps 1 to 14, exposure is started by a mechanism (not shown). At this time, the flow moves to step 15, the exposure time T4 is measured, and after the time T4 has elapsed, the step moves to 16.

Step 16: Output H from the output port P6. Step 17: Output H from the output port P4.

Then, the NOR gate 103 is selected and the mode is set to the open mode, and the steps after step 18 are executed.

Steps 18 to 21 are steps 8 to 1 described above.
The same as No. 1, by which the step pulse is transmitted to the counter through the gate 103. At this time, since the mode has shifted to the open mode, the counter counts down, and the coils 12 and 13 of the motor perform energization control in the reverse order of the narrowing mode.
The diaphragm shifts to the open side by 1/8 step.

When the aperture moves to the open position (see FIG. 5) in the process of shifting the aperture to the open side as described above,
Since the substrate 14 and the brush 17 of FIG. 1 shift from on to off, the switch I formed by the substrate 14 and the brush 17
Is turned off and the data is input to the input port P1 of the computer. Further, since H is input to the input port P2 when the count value of the counter is 0, when H is input to both the port P1 and the port P2, the rotor is in the state of shifting to that in FIG.

When it is detected in step 22 that H is input to the input port P1 and H is input to P2, the step shifts from the repetition of steps 18 to 21 to 23. Step 23: Wait for the lapse of time T5. Step 24: Output L from the output port P6 to stop energizing the motor. Step 25: Obtain the number N1 of changes in the output level (L → H) of the output port P5 during the open mode.

The number N0 of output level changes of the output port P5 in the narrowing mode and the number N1 of output level changes of P5 in the open mode are N0 = N1 when the motor responds to the step pulse. However, if the motor does not start up or does not operate up to the desired aperture diameter due to the motor not responding to the step pulse, N0 ≠ N1.

At step 26, the output level change count N
0 and N1 are compared, and if N0 ≠ N1, step 27
Then, H is output to P7 to cause the light emitting LED 100 to emit light, and the diaphragm operation abnormality warning is output.

[0045]

As described above, the aperture control device of the present invention compares the number of step pulses when driving from the open position to the aperture side with the number of step pulses when driving from the aperture position to the initial position. , It is possible to give an opportunity to redo the shooting by detecting an abnormality of the diaphragm operation due to the delay of the response of the motor and warning the user.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an embodiment of a diaphragm control device according to the present invention.

FIG. 2 is an explanatory diagram for explaining a driving principle of a motor.

FIG. 3 is an explanatory diagram showing a power supply timing of a motor.

FIG. 4 is a block diagram showing a control circuit when the aperture control device is arranged in a camera.

FIG. 5 is an explanatory diagram illustrating a relationship between a motor of the aperture control device and a step position.

FIG. 6 is a circuit diagram showing an embodiment of a distribution circuit and a driver circuit in the configuration of FIG.

FIG. 7 is a count value of the counter of FIG. 6 and a gate 123.
Explanatory drawing which shows the relationship of the output states of -126.

8 is a count value of the counter of FIG. 6 and the coil 12,
Explanatory drawing which shows the relationship of the electricity supply state of 13.

9 is an explanatory view showing a flow for explaining the operation of the control circuit of FIG.

[Explanation of symbols]

1 ... Annular base plate 2 ... Rotor shaft 3 ... Rotor 4 ... Pinion gear 5 ... Bearing plate 6, 7 ... Stator 8, 9 ... Stator 10, 11 ... Iron core 15 ... Cam plate 16 ... Aperture blade 17 ... Rotating ring 18 ... Flexible print Plate 100 ... Light emitting LED 101 ... Microcomputer 105-107 ... Flip-flop 115-122 ... AND gate 128-131 ... AND gate 12,13 ... Coil 136-143 ... Transistor

Claims (1)

[Claims] 1. A diaphragm control device configured to drive a diaphragm blade by a step motor, wherein a pulse supplied to the step motor when the diaphragm blade is driven by the step motor from a diaphragm open state to an arbitrary diaphragm state. Means for detecting an abnormality of the aperture control device by comparing the number of pulses and the number of pulses supplied to the step motor when the aperture blade is driven by the step motor from the narrowed state to the open state, and the abnormality is detected by the means. And a means for generating a warning signal when triggered.