JPS6319633A - Shutter controller for camera - Google Patents

Abstract

PURPOSE:To vary shutter aperture characteristics by providing a shutter aperture degree detecting means, a shutter control means, and a shutter aperture characteristic varying means which varies the charging/discharging time of a capacitor and varies a reference signal for providing the shutter aperture characteristics according to variation in focal length. CONSTITUTION:A diaphragm hole 32 has the maximum aperture to a light emitting element 33 and a light receiving element 34 when shutter blades are fully closed, decreases in aperture size according to an increase in the aperture degree of the shutter blades, and has the minimum aperture when the shutter blades are fully open. An amplifier 38b constitutes a voltage follower and a control voltage VB charged in the capacitor 38a is applied to the base of a control transistor (TR) 39 through the voltage follower when an on-off switch 37 is off to supply a voltage signal VA to the (+) input terminal of an amplifier 40a through a resistance R1 and also supply a voltage VC through a resistance R2, thereby impressing the reference signal VR3 which provides shutter aperture characteristics to the (-) input terminal through a resistance R3. Consequently, the best shutter aperture characteristics for selected focal length are obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a camera shutter control device.

[Description of Prior Art] A shutter control device for a camera programmatically controls the shutter so as to follow the aperture characteristics through matching control between the detected shutter opening degree and a control signal that provides the shutter aperture characteristics. Are known. Such shutter control devices are also used in bifocal cameras that allow you to select between standard and telephoto, but conventional devices of this type cannot be used with a zoom function where the focal length changes continuously. Ta. However, if the shutter aperture characteristics can be varied according to changes in the focal length, it will be possible to provide the most appropriate shutter aperture characteristics for the selected focal length, which can be applied not only to bifocal cameras but also to zoom functions. This makes it possible to realize a camera that is more convenient to use.

[Object of the Invention] The present invention has been made based on the above-mentioned viewpoints, and an object thereof is to provide a camera shutter control device that can vary shutter aperture characteristics in accordance with changes in focal length.

[Means for Achieving the Object] The present invention provides a shutter control device installed in a camera capable of changing the focal length, which includes an aperture mechanism that monitors the opening degree of the shutter, and an optical link between the aperture mechanism and the aperture mechanism. a shutter having an associated light-emitting element and a light-receiving element, and providing a detection output corresponding to the opening degree of the shutter according to the amount of light received by the light-receiving element by light emitted from the light-emitting element via the diaphragm mechanism; shutter control means for program-controlling the shutter so as to follow the aperture characteristic based on the detection output and a reference signal giving the shutter aperture characteristic; The above object is achieved by a shutter control device for a camera having a shutter aperture characteristic variable means for varying a reference signal giving the shutter aperture characteristic in accordance with a change in the focal length by changing the charge/discharge time of a capacitor.

[Embodiment of the Invention] Figures 1, 2 (A) and 2 CB) are configuration diagrams showing an embodiment of the present invention; Figure 1 is a configuration diagram of a shutter mechanism; Figure 2 (A) ) and FIG. 2 CB) are control circuits having the configuration shown in FIG. 1.

In FIG. 1, 1, 2.3 are shutter blades, and the lens aperture 4 is opened and closed by these three blades. The lens aperture 4 is formed on a substrate (not shown), and each shutter blade 1, 2.3 is provided through this substrate on a lens barrel (not shown) that expands and contracts in accordance with changes in focal length. Each shutter blade 1, 2.3 is
Each arm 1a has an arm 1a, 2a, 3a, respectively.

Support shafts 5.6 fixed to the ends of 2a and 3a and the substrate.
7 and is rotatably supported.

A shutter drive plate 8 is provided between the shutter blades 1, 2.3 and the substrate. The shutter drive plate 8 is in the shape of a thin disc and has a circular opening in the center. It can be easily rotated around the center. The shutter drive plate 8 is provided with pins 9, 10.degree. 11 projecting from the shutter blades 1, 2.3 to engage with each shutter blade 1, 2.3. Each bin 9, 10.11 has a shutter blade 1, 2.
Elongated holes 12, 13 formed in arm portions 1a, 2a, 3a of 3
．． 14, and the rotation of the shutter drive plate 8 opens and closes the shutter blades 1, 2.3. The shutter drive plate 8 has a drive shaft 1 extending in the outer radial direction.
5 and an opening detection plate 16 are integrally formed.

A parallel arm 17a extending horizontally at the lower end of the drive shaft 15
, 17b are formed, and the arm 17a.

17b, a long groove 20 is defined which engages the pin 19 of the bin member 18. The shutter drive plate 8, together with the shutter blades 1, 2.3 and the substrate, maintains the engagement between the pin 19 of the pin member 18 and the long groove 20, and expands and contracts the lens barrel as the focal length changes. It is designed to move in the direction of the arrow A-B shown in the figure. Expansion and contraction of the lens barrel as the focal length changes is provided by the well-known bifocal function and zoom function.

The pin member 18 is fixedly arranged inside the camera or is connected to a movable piece 22 of a near solenoid 21.
In this example, the pin member 18 is operated in the direction of the arrow C-D in the figure by rotation around the support shaft 23 of the pin member 18.
When the pin member 18 moves in the direction D, the shutter blades 1, 2.3 close, and when the pin member 18 moves in the direction C, the shutter blades 1.2.3 open. Even if the lens barrel expands or contracts as the focal length changes, the linear lens 21 does not move.

FIG. 3 is a configuration diagram of the beam near solenoid 21. The movable piece 22, together with the electromagnetic winding 24 and the permanent magnet 25, is held by an outer frame 26 and an inner frame 27, 28. The outer frame 26 and the inner frames 27 and 28 are made of a material with good magnetic permeability, such as soft iron. The outer frame 26 is a U-shaped frame having three substantially rectangular surfaces 26-1, 26-2, and 26-3, and one inner frame 27 is provided inside the surface 26-1. A permanent magnet 25 is placed inside the surface 26-3 opposite to 26-1.
The other inner frame 28 is provided via. The inner frames 27 and 28 are each made of a rectangular plate, and the end portions protruding from the outer frame 26 are bent so as to be spaced apart and facing each other, and the tip portions 27a and 28a are convexly formed in an arc shape. . The permanent magnet 25 sandwiched between the surface 26-3 of the outer frame 26 and the inner frame 28 is a rectangular plate-shaped magnet, and in this example, the permanent magnet 25 is provided so that the surface in contact with the inner frame 28 is the north pole. . Between the inner frames 27 and 28 is a zero winding frame 29 in which the electromagnetic winding 24 is provided via a plastic winding frame 29.
The zero-winding frame 29 has a through space 30 in the center for receiving the movable piece 22 and has flanges 29a and 29b formed on both end faces, and is fixed to the outer frame 26 via the flanges 29a and 29b. has been done. The movable piece 22 is a substantially elongated plate made of a material with good magnetic permeability, and is disposed through the penetrating portion 30 of the winding frame 29 . Movable piece 2
2, one end 22a protrudes from between the tip portions 27a and 28a of the inner frame 27.degree. 28, and the other end 22b is pivotally supported by a support shaft 23 so as to be rotatable in the left-right direction in the drawing. The pin member 18 described in FIG. 1 is attached to one protruding end 22a of the movable piece 22. The movable piece 22 has tip portions 27a, 2 of the inner frame 27.28 near one end 22a.
It is provided with overhanging parts 31a and 31b extending along the inner surface of 8a so as to be perpendicular to the axial direction. Inner frame 27.28
The tip portion 27a.

The sides of the overhanging parts 31a and 31b facing the inner surface of 28a are as follows:
The distance between the inner surfaces of the tip portions 27a and 28a is the same as that of the movable piece 2.
The tip portion 2 is designed to remain approximately constant regardless of the rotation of the tip portion 2.
It is formed in an arc shape like the inner surfaces of 7a and 28a.

When the electromagnetic winding 24 is in a non-excited state, the movable piece 22 is given a magnetic flux that passes through the permanent magnet 25 → inner frame 28 → tip portion 28a → movable piece 22 → outer frame 26 → permanent magnet 25, so the permanent magnet 25 The end 22a is attracted to the inner frame 28.
It is held in a state tilted to the right in FIG. 3 so as to abut against the tip end portion 28a. In this state, as shown in FIG. 1, the pin member 18 is operated to the D side, and the shutter blades 1.2.3 are held in the closed state. On the other hand, the electromagnetic winding 2
4 is excited, the surface 26-1 of the outer frame 26 and the inner frame 2
7→Face 26-2 of outer frame 26→Other end 22b of movable piece 22→
One end 22a of the movable piece 22 → the tip portion 27a of the inner frame 27 →
A first magnetic flux passing through the surface 26-1 of the outer frame 26 and the inner frame 27.

Surface 26-3 of outer frame 26 and inner frame 28 → surface 2 of outer frame 26
6-2→Other end 22b of movable piece 22→One end 2 of movable piece 22
2a → tip portion 28a of the inner frame 28 → surface 26- of the outer frame 26
3 and a second magnetic flux passing through the inner frame 28 are generated. Second
The magnetic flux acts to cancel out the magnetic flux of the permanent magnet 25, and the attractive force of the first magnetic flux acts on the movable piece 22, so that the movable piece 22 rotates toward the tip portion 27a of the inner frame 27. Become.

The glue near solenoid 21 having such a structure has a movable piece 22.
Regardless of the rotational position of the magnet, a substantially constant torque is generated in accordance with the excitation current. That is, when a certain value of excitation current is applied to the electromagnetic winding 24, the torque acting on the movable piece 22 is approximately the same at any position between the tip portions 27a and 28a of the inner frame 27.28. If the magnitude of the excitation current is changed, the torque changes, and the rotational speed of the movable piece 22 when the electromagnetic winding 24 is excited changes accordingly.

Returning to FIG. 1, the opening detection plate 1 integrated with the shutter drive plate 8
6 has an aperture hole 32 formed therein, and a light emitting element 33 and a light receiving element 34 are fixedly arranged with respect to the aperture hole 32 with the aperture hole 32 in between.
The projected light of 0 is applied to the light receiving element 34.
The light emitting element 33 and the light receiving element 34 are fixed to the substrate on the back side of the shutter drive plate 8, and while maintaining a fixed position relative to the aperture hole 32, the shutter is driven by expansion and contraction of the lens barrel as the focal length changes. It is adapted to move together with the plate 8. The diaphragm hole 32 is arranged so that the light emitting element 33 and light receiving element 34
The maximum opening occurs when the shutter blades 1, 2, and 3 are fully closed, and the shutter blade l.

The size of the opening decreases as the opening degree of 2.3 increases, and the opening becomes the minimum opening when the shutter blades 1 and 2.3 are fully opened. Therefore, the amount of light received by the light receiving element 34 is maximum when the shutter blades 1, 2.3 are fully open, and the amount of light received by the light receiving element 34 is maximum when the shutter blades 1, 2.
,2.3 decreases as the opening degree increases, and the shutter blade 1,
0 light emitting element 33.2.3, which is the minimum when fully open. As the light receiving element 34, a light emitting diode, a photodiode, etc. can be used.

The shutter mechanism configured as described above is controlled by the control circuits shown in FIGS. 2(A) and 2(B).

In FIG. 2(A), 35 is a light receiving circuit that outputs the photoelectric output of the light receiving element 34 as a voltage signal VA.
5a and a resistor 35b.

The voltage V applied to the (+) input terminal of the amplifier 35a
R2 is a reference voltage for pull-up. The voltage signal v8 which is the output of the light receiving circuit 35 is expressed as vII=V, assuming that the resistance value of the resistor 35b is the photocurrent of the R1 light receiving element 34.
It becomes R2 + engineering・R.

A control amplifier 36 receives the voltage signal VA and the reference voltage VRI, and outputs a control voltage v8 that controls the driving current of the light emitting element 33 so that the voltage signal V^ becomes the reference voltage VRI. Reference numeral 37 denotes an open/close switch for turning on/off the supply of the control voltage Vll, which is opened by an open signal applied in synchronization with the shutter release and closed by a close signal applied in synchronization with the end of exposure. 38 is open/close switch 3
This is a hold circuit that holds the control voltage VB applied through VB, and includes a capacitor 38a and an amplifier 38b. Amplifier 38b constitutes a voltage follower,
When the open/close switch 37 is turned off, the control voltage vB charged in the capacitor 38a is applied to the base of the control transistor 39 through the voltage follower. The collector of the control transistor 39 is the light emitting element 3
3 to the power supply, and its emitter is grounded. 40 is an arithmetic circuit having an operational amplifier 40a, to which a voltage signal ■^ is applied via a resistor R1 to the (+) input terminal of the amplifier 40a, and a voltage VC is applied via a resistor R2; resistor R3
A reference signal VR3 giving the shutter opening characteristics is applied via the reference signal VR3. The voltage Vc cancels the magnetic flux of the permanent magnet 25 of the linear solenoid 21 and
This is the bias voltage so that no force acts on the The reference signal VR3 is provided by a control circuit shown in FIG. 2(B), which will be described later. If the resistance values are equal, the arithmetic circuit 40 outputs (VA + VC - V R3), and the arithmetic output VD makes VA equal to Vll.
give. 41 is a linear solenoid drive circuit that drives the electromagnetic winding 24 of the linear solenoid 21 according to the calculation output VD of the calculation circuit 40. Linear solenoid drive circuit 4
1 is set in a driving state in synchronization with the shutter release according to a control signal, and is put in a non-driving state in synchronization with the end of exposure. As a result, excitation output is not given to the electromagnetic winding 24 except during the end of exposure from the shear and tallerize, and the movable piece 22 is attracted to the permanent magnet 25, and the shutter blades 1, 2.3 are in the closed state. It will be retained.

In FIG. 2 CB), 42 is a potentiometer that provides a voltage signal VE that changes according to the expansion and contraction of the lens barrel as the focal length is changed, and 43 is a constant current that provides a constant current rs that corresponds to the voltage signal VE of the potentiometer 42. This current circuit is inserted between the power supply and ground via the collector emitter circuit of the transistor 44. In this example, the constant current IS is such that its current value increases as the focal length increases. The base of transistor 44 is connected to the collector and to the bases of further transistors 45 and 46. transistor 45.4
6 has its emitter connected to the power supply, and forms a current mirror together with the transistor 44 mentioned above. Therefore, when a constant current Is corresponding to the voltage signal VE flows through the collector of the transistor 44, the other transistor 45
, 46 also flows through the constant current IS. The collector of transistor 45 is connected to the collector of control transistor 47 and to the collector of transistor 48. The emitter of the control transistor 47 is grounded, and a shutter opening/closing signal is applied to its base via a resistor 49. The shutter opening/closing signal goes to an L level in synchronization with the shutter release, and goes to an H level when the shutter starts closing. transistor 48
has its emitter grounded, its base connected to its collector, and another transistor 50.
It is connected to the base of 51. transistor 50.5
1 has its emitter grounded and constitutes a current mirror together with the transistor 48 mentioned above. The collectors of transistors 50 and 51 are both connected to transistor 4 at point P.
6 collector. Transistor 48°5
0.51 is turned off when the control transistor 47 is turned on, and turned on when the control transistor 47 is turned off. The control transistor 47 controls the shutter [5[L according to the signal]
When the level is high, it is off, and when it is high, it is on. 52 is a limiter circuit, and 53 is a capacitor. The limiter circuit 52 includes amplifiers 52a, 52b and a diode 52c.
, 52d. The above-mentioned reference voltage VRI is applied to the (+) input terminal of the amplifier 52a, and the other amplifier 5
The above-mentioned reference voltage vR2 is applied to the (+) input terminal of 2b. Amplifier 52a.

The (-) input terminal of 52b connects the point P and the aforementioned reference signal VR.
3. The output terminal of the amplifier 52a is connected to the output terminal 54 via the diode 52c inserted in the reverse direction, and the output terminal of the other amplifier 52b is connected to the diode 52 inserted in the forward direction.
It is connected to the output terminal 54 via d. The voltage applied to the output terminal 54 by such a limiter circuit 52 is:

The upper limit is regulated by the reference voltage VRI, and the lower limit is regulated by the reference voltage VR2. Capacitor 53 is inserted between the (+) input terminal of amplifier 52a and point P. The output terminal 54 providing the reference signal Vll is connected to the corresponding terminal of the arithmetic circuit 40 in FIG. 2(A).

Figure 4 is an explanatory diagram of the reference signal VR3. (a) ゛ is for a long focus, broken line (b) is for a short focus, - dashed line (C
) shows the reference signal VR3 in the case of intermediate focus. The reference signal VR3 is the reference voltage VR before the shutter release.
When the shutter release is performed, the capacitor 53 is charged and decreases toward the reference voltage VR2, and after becoming equal to the reference voltage VR2, the time 1. Alternatively, at the start of the closing operation at t2 or t3, the slope of the decrease and increase of the reference voltage VR3, which increases toward the reference voltage VRI as the capacitor 53 discharges, is regulated by the charging and discharging time of the capacitor 53, The discharge time becomes shorter as the constant current IS becomes larger. When the focal length is long, the constant current Is becomes large, so the slope becomes steeper, as shown in solid line (a), and as the focal length becomes shorter, the constant current Is becomes smaller, so the slope becomes gentler. It looks like the dashed line (C) and the broken line (b).
The shutter opening/closing signal for turning on/off the control transistor 47 in FIG. CB) goes to L level in synchronization with the shutter release, and then goes to H level at time tl, t2, or t3. This is detected by measuring the elapsed time when the shutter starts closing.

With the above configuration, Figure 2 (A) and Figure 2 (B)
When power is not applied to the control circuit of the linear solenoid 21, the electromagnetic winding 24 of the linear solenoid 21 is de-energized and the movable piece 22 is attracted by the permanent magnet 24, causing the shutter blades 1, 2, .
3 is fully closed, and the aperture hole 32 is fully open to the light emitting element 33 and the light receiving element 34. When power is applied to the control circuit prior to shutter release, the light emitting element 33 is driven by the control voltage Va of the control amplifier 36, which controls the drive current of the light emitting element 33 so that the voltage signal V^ becomes the reference voltage VRI. , the light emitting element 33 is controlled so that the amount of light emitted is constant. On the other hand, in the control circuit of FIG. 2(B), when the power is applied, a voltage signal vE corresponding to the focal length is applied from the potentiometer 42, and a constant current Is corresponding to this voltage signal V[ is applied to the transistor 44.
It flows to the collector of 45.46°. Since this is before the shutter release, the shutter opening/closing signal is at H level and the transistors 4B and 50.51 are in the off state. Therefore, the potential at point P becomes the reference voltage VR+, and the output terminal 54
A reference signal VR3, which is equal to the reference voltage VRI, is output. In this state, the voltage signal ■^ and the reference signal VR3
are in the same state, so the arithmetic circuit 4 of FIG. 2(A)
The calculation output Vo of 0 becomes the bias voltage VC. Since the linear solenoid drive circuit 41 is set to a non-drive state by the control signal, the electromagnetic winding 24 of the linear solenoid 21 is not excited based on the bias voltage VC. Without,
The attraction state by the permanent magnet 25 continues, and the shafter blade 1
, 2.3 is maintained fully closed.

When the shutter release is performed, the open/close switch 37 is opened in synchronization with this, and the control voltage VB is applied to the hold circuit 3.
It is held at 8. Since the transistor 39 performs constant current control on the drive current of the light emitting element 33 based on the held control voltage v8, the amount of light emitted from the light emitting element 33 is held constant. On the other hand, the control circuit in FIG. 2(B) is
When the shutter is released, the shutter opening/closing signal becomes L level, so the control transistor 47 is turned off, and the transistors 48, 50, and 51 are turned on.

Since the transistors 4g and 50.51 constitute a current mirror, the capacitor 53 is charged with a constant current Is. Assuming that the lens barrel is operated so as to become the focal point, the reference signal VR3 decreases from the reference voltage VRI to the reference voltage VR2 according to the solid line (a) in Fig. 4, as shown in Fig. 2 (A). The arithmetic circuit 40 is the light receiving circuit 35
A calculation output Vo is given to the linear solenoid drive circuit 41 to make the voltage signal V^ applied via the reference signal VR3 equal to the reference signal VR3. Since the linear solenoid drive circuit 41 is placed in the drive state by shutter release, the drive circuit 41
The electromagnetic winding 24 of the linear remade 21 is excited through the magnet, the movable piece 22 rotates toward the side opposite to the permanent magnet 25, and the shutter blade ! ,2
．． 3 opening operation is performed. Shutter blade 1.2.3
The opening degree of is reflected in the voltage signal VA by the decrease in the amount of light received by the light receiving element 34 due to the decrease in the aperture of the aperture hole 32 due to the rotation of the shutter drive plate 8, and this voltage signal is reflected in the reference signal VR.
Excitation control of the electromagnetic winding 24 is performed via the arithmetic circuit 40 and the linear solenoid drive circuit 41 so that the value always matches 3. Therefore, the shutter blades 1.2.3 are opened at a speed that follows the decreasing slope of the reference signal VR3.

When the shutter opening/closing signal goes to H level at time tl in FIG. 4, the control transistor 47 in FIG. The reference voltage R7 increases toward the reference voltage VRI in response to the discharge of the reference voltage R7. Therefore, similarly to the above, the movable piece 22 rotates toward the permanent magnet 25 in accordance with the calculation output vD that makes the voltage signal VA equal to the reference signal VR3, and the speed follows the slope when the reference signal VR3 increases. The shutter blades 1, 2.3 are then closed.

When the lens barrel is moved to the intermediate focus or short focus position, the value of the constant current IS is reduced via the potentiometer 42 and the constant current circuit 43, and the charging/discharging time of the capacitor 53 becomes longer, and the reference signal VR3 is output as shown in FIG. (C) or (
b) is given. By moving the lens barrel, shutter blades 1, 2.
3 and the shutter drive plate 8 move together as described in the configuration description.

In the embodiment described above, the slope when the reference signal VR3 decreases and increases is the same, but by inserting a resistor between the emitter of the transistor 50 and the ground, it is possible to change only the slope when decreasing, that is, the opening operation time of the shutter. Can be done. Also,
In the above example, three types of aperture characteristics were shown, but the constant current I
It is clear that the aperture characteristics change continuously depending on the value of s, and this can also be applied to the zoom function.

[Effects of the Invention] As explained above, according to the present invention, charging and discharging of a capacitor is utilized when program-controlling the shutter to follow the shutter opening characteristics based on the detected shutter opening degree and the shutter opening characteristics. Since the above-mentioned shutter aperture characteristics can be changed according to changes in the focal length, it is possible to provide the most appropriate shutter aperture characteristics for the selected focal length, and it can be applied not only to two-point cameras but also to zoom cameras. It is possible to provide a camera shutter control device that can be applied to other functions as well.

[Brief explanation of drawings]

1, 2(A), and 2(B) are block diagrams showing one embodiment of the present invention, FIG. 3 is a block diagram showing an example of the linear solenoid in FIG. 1, and FIG. 4 is a block diagram showing an example of the linear solenoid in FIG. FIG. 3 is an explanatory diagram of a reference signal that provides shutter opening characteristics. 1.2.3... Shutter blade 8... Shutter drive plate 16... Opening detection plate 18... Pin member 21... Linear solenoid 21... Movable piece 24... Electromagnetic winding 25...Permanent magnet 3
2... Aperture hole 33... Light emitting element 34... Light receiving element 35... Light receiving circuit 36... Control amplifier 37... Open/close switch 38... Hold circuit
40... Arithmetic circuit 41... Linear solenoid drive circuit 42... Potentiometer 43... Constant flow circuit 39.44, 45, 46, 47.4B.

Claims (1)

[Claims] A shutter control device provided in a camera capable of changing the focal length, the device comprising an aperture mechanism for monitoring the opening degree of the shutter, and a light emitting element and a light receiving element optically associated with the aperture mechanism, the aperture mechanism shutter opening detection means for providing a detection output corresponding to the opening of the shutter according to the amount of light received by the light receiving element due to the light emitted from the light emitting element via the light emitting element; and a reference signal for providing the detection output and the shutter opening characteristic. shutter control means for program-controlling the shutter to follow the aperture characteristic based on the aperture characteristic, and a reference signal that provides the shutter aperture characteristic by changing the charging/discharging time of a capacitor based on a current change corresponding to a change in the focal length. and shutter aperture characteristic variable means for varying the shutter aperture characteristic according to a change in the focal length.