JP2001013642A - Automatic exposure controller and film unit with lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a diaphragm plate from being switched even when the subject light quantity is changed in the midst of exposure. SOLUTION: The diaphragm is switched by moving the diaphragm plate by means of a solenoid 51. A diaphragm control circuit is equipped with a solar battery 26 outputting a light quantity signal in accordance with the subject light quantity and a switching transistor 74 actuating the solenoid 51 when the light quantity signal is equal to or above a specified value. A transistor 76 functions to supply a base current to the transistor 74 from a power source battery 39 in order to maintain the actuated state of the solenoid 51. A stopping switch 63 functions to stop the actuation of the battery 26. A main switch 62 is turned on by half-depressing a shutter button and, on the other hand, the switch 63 is turned off by fully depressing the shutter button. Thus, even when the subject light quantity is changed in the midst of exposure, the state of the solenoid 51 is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for moving an aperture plate provided with an aperture opening in accordance with the amount of light of a subject.
The present invention relates to an automatic exposure control device for performing exposure control and a lens-equipped film unit having the same.

[0002]

2. Description of the Related Art A film unit with a lens is known as a simple camera of a single use type in which a photographic film is pre-loaded. This film unit with lens
Since it is a single-use type, thorough simplification of the structure and cost reduction are achieved. On the other hand, from the demand for image quality improvement, the aperture is automatically switched according to the amount of light of the subject,
Devices equipped with an automatic exposure control device that performs exposure control have been studied.

[0003] This automatic exposure control apparatus is, for example, as disclosed in Japanese Patent Application Laid-Open No. 9-5817, a diaphragm plate provided with a diaphragm opening, and a control unit for switching the diaphragm opening by moving the diaphragm plate. Consists of The control unit includes an electromagnet that attracts and moves the diaphragm plate, a main switch that turns on / off a power supply path to the electromagnet by half-pressing a shutter, and a photometry unit that detects a subject light amount and outputs a light amount signal. And a switching transistor that receives the light amount signal and activates the electromagnet when the signal reaches a predetermined value. According to this, the control section is operated by the half-pressing operation of the shutter, and the exposure control is automatically performed according to the light amount of the subject, so that anyone can easily take a picture with an appropriate exposure amount.

[0004]

However, in the above-described automatic exposure control device, the light intensity signal is continuously output from the photometer even during the exposure in which the shutter blades are opened and closed. For this reason, when the light amount of the subject changes during the exposure, the attraction force of the electromagnet may change and the diaphragm plate may move. This is because the aperture plate moves during the exposure, making it impossible to secure an accurate exposure time. In the worst case, the aperture plate blocks the optical path of the photographing, and the subject image is exposed to the film. The problem that it cannot be done arises.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described drawbacks, and has as its object to provide an automatic exposure control device in which an aperture plate does not move even if the amount of light of a subject changes during exposure.

[0006]

In order to achieve the above object, an automatic exposure control device according to the present invention has a first position in which at least one aperture is formed and the aperture is inserted into a photographing optical path. An aperture plate movably provided between a second position where the aperture opening is retracted from the photographing optical path, and a first aperture plate when the subject light amount is equal to or more than a predetermined value.
When the subject light amount is equal to or less than a predetermined value, in the automatic exposure control device including a control unit that holds the second position, the control unit drives the diaphragm plate, A main switch for turning on / off a power supply path to the driving means in conjunction with a half-press of a shutter button;
A photometric unit that outputs a light amount signal corresponding to a light amount of a subject, a switching unit that activates the driving unit when the light amount signal is equal to or more than a predetermined value, and an aperture plate that has moved to the first position before the start of exposure, A first holding means for holding the aperture plate at the first position even when the light amount of the subject decreases during exposure.

Further, when the exposure is started in a state where the diaphragm plate is held at the second position, the diaphragm plate is held at the second position even when the amount of the subject increases during the exposure. A second holding means is provided.

Further, the stop switch and the main switch are connected to each other by three elastic first to third metal contact pieces and the first contact piece when the shutter button is not pressed. The second contact piece is in contact with the second contact piece, and the second contact piece and the third contact piece are integrated with each other with a switch member including a holding portion so as to be in non-contact, This switch member is linked to the pressing operation of the shutter button.

Further, the film-with-lens unit of the present invention has the above-mentioned automatic exposure control device incorporated in a film-with-lens unit in which an unexposed photographic film is loaded in advance.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 2 and 3, which schematically show the appearance and internal structure of a film unit with a lens 11 in which an automatic exposure control device according to the present invention is incorporated, the film unit with a lens 11 has an exposure unit in the center. 12 are provided,
The main body base 1 with the strobe device 13 mounted next to it
4, a unit main body composed of a front cover 16 and a rear cover
8 and a photo film 19 drawn out of the cartridge 18 into a roll form. The cartridge 18 and the photographic film 19 are pre-installed in the cartridge storage chamber 14a and the film storage chamber 14b formed in the main body 14 at the time of manufacturing the film unit with the lens.

The front cover 16 has a photographing window 21 exposing a photographing lens 20, a finder objective window 22,
A strobe light emission window 23 is formed, and on its upper surface,
Shutter button 28, film counter window 29 on top
Are formed. A solar cell 26 is provided above the photographing window 21.
However, a strobe switch 27 is attached beside it. The solar cell 26 is a photometric unit of the automatic exposure device,
A current corresponding to the amount of received light is generated, and this is output as a light amount signal. As a material of the solar cell 26, for example, amorphous silicon is used. When the light amount signal reaches a predetermined value or more while the shutter button 28 is half-pressed, the aperture is automatically switched.

The strobe switch 27 is used to start charging of the strobe, and is slidably provided in a vertical direction. When the charging of the strobe is completed, the charging completion lamp is turned on, and this light passes through the light guide 25 and is confirmed by the photographer.

The rear cover 17 has a finder eyepiece window 31,
A charge completion confirmation window 3 that exposes the light guide 25 on the upper surface.
2, and a bottom cover 17a, which covers the bottom openings of the cartridge storage chamber 14a and the film storage chamber 14b in a light-tight manner.
17b are integrally formed. The bottom cover 17a is opened when the cartridge 18 in which the photographed photo film has been taken in is taken out.

A hoisting knob 33 is provided above the cartridge storage chamber 14a, and a hoisting shaft integrally formed on the lower surface thereof engages with the spool of the cartridge 18. By rotating the winding knob 33 for each shooting,
The photo film that has been taken is one cartridge per frame.
Get caught in 8. The shutter mechanism incorporated in the exposure unit 12 is charged for the next photographing in conjunction with the winding of one frame of the film, and the winding lever 33 by the lock lever incorporated in the exposure unit 12 when one frame of the film is fed. Is locked.

The strobe device 13 includes a main condenser 3
4, a circuit board 37 on which circuit components such as a synchro switch 36 and a step-up coil are mounted, a light emitting section 38 including a strobe discharge tube and a reflector, and a power supply battery 39.
On the circuit board 37, a circuit pattern is printed, and various circuit elements are attached to form a strobe circuit and an aperture control circuit. On the front surface of the circuit board 37, a charging switch contact piece 41 and a support plate 42 for supporting the strobe switch 27 in front of the charging switch contact piece 41 are attached. The charging switch contact piece 41 is turned on / off by sliding the strobe switch 27.

The exposure section 12 is based on a dark box base 46 projecting forward in the shape of a rectangular cylinder, and is provided with a shutter mechanism, a film winding mechanism, a finder mechanism, a film counter plate and the like. is there. Further, the exposure unit 12 holds an objective and an eyepiece constituting a finder optical system. An exposure frame is formed on the back of the dark box base 46, and limits the exposure range for one frame on the front of the photographic film 19 sent to the shooting position.

As shown in FIG. 4, a shutter opening 46a is formed on the front surface of the dark box base 46, and an aperture plate 47, shutter blades 48, and a shutter cover 49 covering these are mounted in front of the shutter opening 46a. Can be Dark box base 46
A solenoid 51 is attached to the side as a drive unit for driving the aperture plate 47. The taking lens 20 is incorporated in the shutter cover 49, and a normal aperture (not shown) is formed behind the taking lens 20. An operation switch 5 for operating an aperture control circuit in conjunction with the shutter button 28 is provided on the front surface of the shutter cover 49.
2 is attached.

The shutter blade 48 is of a well-known kicking type, and includes a blade portion 48a and a mounting portion 48b extending above the blade portion 48a.
Consists of The mounting portion 48b is engaged with a pin 53 formed on the front surface of the dark box base 46, and with the pin 53 as a center axis, a closing position for closing the shutter opening 46a and the opening 46
It is rotatably mounted between an open position where a is opened. A first spring 54 is mounted between the mounting portion 48b and the dark box base 46, and the shutter blade 48 is urged in the closing position direction by the first spring 54. When the shutter button 28 is pressed, the shutter mechanism operates, and the kick lever 56 kicks the head of the mounting portion 48b. Thereby, the blade portion 48a rotates, and the shutter opening 46a is opened and closed.

The mounting portion 48b is provided with a pressing portion 48c. The pressing portion 48c is for emitting strobe light in conjunction with opening and closing of the shutter. When the shutter button 28 is fully pressed and the shutter blade 48 reaches the fully open position, the synchro switch 36 is pressed and turned on. .

The diaphragm plate 47 is formed with a small diaphragm opening 47a having a smaller diameter than a normal diaphragm opening. Aperture plate 47
Is attached to a shaft 57 provided in the dark box base 46,
With this axis 57 as the central axis, a small aperture 4
It is rotatable between a first position at which the small aperture 7a is inserted and a second position at which the small aperture opening 47a is retracted from the photographing optical path. The aperture plate 47 is urged by a second spring 61 so as to rotate toward the second position.

The movable iron core 58 of the solenoid 51 has a groove 5
The groove 58a is engaged with a pin 59 provided on the aperture plate 47. Thus, when the solenoid 51 causes the movable iron core 58 to project to a predetermined position, the aperture plate 47 rotates toward the first position. The solenoid 51 holds the diaphragm plate 47 at the first position against the bias of the second spring 61 while the solenoid is in the operating state. When the solenoid 51 stops operating, the second spring 6
1 rotates the diaphragm plate 47 toward the second position, and stores the movable iron core 58 inside the solenoid 51.

The operation switch 52 is a shutter button 28
It is operated by a pressing lever 28a provided below. As shown in FIGS. 5 and 6, the operation switch 52 is
It comprises three metal contact pieces, a first contact piece 52a, a second contact piece 52b, and a third contact piece 52c, and a holding portion 52d formed of an insulating material and holding these. The first to third contact pieces 52a,
52b and 52c are formed of elastic thin metal contact pieces. The end of the holding portion 52d is attached to the circuit board 37, and thereby the first to third contact pieces 52a, 52
One end of each of b and 52c is connected to the aperture control circuit.

The second contact piece 52b and the third contact piece 52c constitute a main switch 62 for activating an aperture control circuit by turning on / off a power supply path to the solenoid 51. At the open end of the second contact piece 52b, an insulating piece 52e is provided.
The operation switch 52 is interlocked with the pressing operation of the shutter button 28 by contact with the shutter button 28. The second contact piece 52b and the third
The contact piece 52c is in a non-contact state in a normal state where the shutter button 28 is not pressed. Shutter button 2
When the button 8 is half-pressed, the second contact piece 52b is elastically deformed, comes into contact with the third contact piece 52c, and the main switch 62 is turned on.

On the other hand, the first contact piece 52a and the second contact piece 52b constitute a stop switch 63 for stopping the operation of the solar cell 26 so as not to output a light amount signal while the shutter is operating. The first contact piece 51a and the second contact piece 51b are in a contact state in a normal state where the shutter button 28 is not pressed. When the shutter button 28 is in the half-pressed state, it is still in the contact state (ON). Further, when the shutter button 28 is pressed down and fully pressed, the first contact piece 51a and the second contact piece 51b are moved. Until the kicking lever 56 kicks the shutter blade 48, it is in a non-contact state (OFF).

As described above, since the main switch 62 and the stop switch 63 are formed as one integrated member, the interlocking of the switches 62 and 63 and the shutter button 28 is realized with a simple structure. . Of course, these need not be provided integrally, but may be provided separately.

In FIG. 1 showing an example of a strobe circuit and an aperture control circuit, a strobe circuit includes a charging switch contact piece 41.
Is turned on, the oscillating transistor 66 conducts and the booster coil 67 operates. The main capacitor 34 and the trigger capacitor 68 are charged by the secondary current obtained from the boosting coil 67, and when the main capacitor 34 reaches a specified charge level, the neon tube 69 is turned on. When the synchro switch 36 is turned on by opening the shutter blade 48, the trigger coil 68 is discharged by discharging the trigger capacitor 68.
A current flows through the primary side of the first, and a high voltage is generated at the trigger electrode 72 connected to the secondary side. As a result, the electric charge stored in the main capacitor 34 is
Through the device and emit a strobe light.

The aperture control circuit comprises a solar cell 26, a solenoid 51, a switching transistor 74, a transistor 76, a main switch 62, a stop switch 63 and the like. The switching transistor 74 controls the operation of the solenoid 51 in accordance with the amount of light of the subject.
The operation starts when the base current supplied from the solar cell 26 to the transistor 74 reaches a predetermined value or more. The predetermined value may be, for example, the sunshine in a clear day (about 100,000 to 12
Is set to the current value generated when the solar cell 26 receives 10,000 lx). Of course, you may set below.

The main switch 62 is wired between the power supply battery 39 and the solenoid 51.
On / off the power supply path to When the switching transistor 74 is in the operating state when the main switch 62 is turned on, current flows from the power supply battery 39 to the solenoid 51, and the movable iron core 58 moves. At this time, the current from the power supply battery 39 is also supplied to the transistor 76 to operate the transistor 76. Transistor 7
6 is for supplying a current from the power supply battery 39 to the switching transistor 74 while the main switch 62 is on.

Therefore, when the switching transistor 74 is in the operating state, the main switch 62 is once turned on.
Then, even if the current value supplied from the solar cell 26 to the transistor 74 falls below a predetermined value, the transistor 74 maintains its operating state with the current supplied from the transistor 76 side. You. As described above, the transistor 76 holds the aperture plate 47 at the first position even when the light amount of the subject decreases during exposure.
Function as holding means.

On the other hand, the stop switch 63 stops the operation of the solar cell 26 before the start of the exposure. Thus, when exposure is started in a state where the subject light amount is small and the diaphragm plate 47 is held at the second position, even when the subject light amount increases during the exposure, the diaphragm plate 47 is moved to the second position. It functions as second holding means for holding the position.

The operation of the above configuration will be described below with reference to FIGS. When taking a picture in fine weather, the base current supplied from the solar cell 26 to the switching transistor 74 reaches a predetermined value, and the transistor 74 operates. In this state, when the shutter button 28 is half-pressed, as shown in FIG. 7A, the main switch 62 is turned on, and the diaphragm plate 47 rotates toward the first position, and the small diaphragm opening is opened. 47a is set on the photographing optical path.
At this time, the transistor 76 is also turned on, and the supply of the base current from the power supply battery 39 to the switching transistor 74 is started.

Further, when the shutter button 28 is depressed, the stop switch 63 is turned off, and the operation of the solar cell 26 is stopped. Further, when the shutter button 28 is pushed in and fully pressed, the kicking lever 56 kicks the shutter blade 48, and the shutter blade 48 opens and closes. During the exposure, the operating state of the switching transistor 74 is maintained by the supply of current from the power supply battery 39, so that the operating state of the solenoid 51 is also maintained. Therefore, the diaphragm plate 47 does not rotate toward the second position. The photographing light incident from the photographing lens 20 passes through a small aperture opening 47c and a shutter opening 46a.
It forms an image on a photo film. Since the exposure amount is adjusted to an appropriate value by the small aperture opening 47c, there is no overexposure.

When the shutter blade 48 reaches the fully opened position, the pressing portion 48c turns on the synchro switch 36. When the main capacitor 34 is being charged, strobe light emission is performed. When the shutter button 28 returns to the normal position, the main switch 62 is turned off, and the operation of the solenoid 51 is stopped. The diaphragm plate 47 includes a spring 61
To return to the second position.

When taking a picture indoors or in cloudy weather, the strobe switch 27 is slid to start charging the main condenser 34. Since the amount of light from the subject is small, the switching transistor 74
Does not reach the predetermined value, the transistor 7
4 does not work. After confirming the completion of the charging in the charging completion display window 29, the photographing is performed. When the shutter button 28 is half-pressed, the main switch 62 is turned on.

In this case, as shown in FIG. 8A, since the switching transistor 74 is not operated, the solenoid 51 is not operated, and the diaphragm plate 47 is not rotated. Further, when the shutter button 28 is pressed, the stop switch 63 is turned off. Thereby, the operation of the solar cell 26 stops. When the shutter blade 4 is further pushed in,
8 is kicked off, and the shutter blade 48 opens to start the operation.

As shown in FIG. 8B, the shutter blade 4
8 is in the fully open position, the synchro switch 36 is
N, strobe light emission is performed. The exposure amount of the photographing light is adjusted by the ordinary aperture opening, so that the underexposure does not occur. Also, during the exposure, even when the amount of light of the subject suddenly increases due to strobe light, a sudden change in the weather, or the like, since the solar cell 26 does not operate, the aperture plate 47 rotates toward the first position. There is nothing to do.

The first example has been described as an automatic exposure control apparatus in which the aperture plate does not rotate due to a sudden change (increase and decrease) in the amount of light of the subject during exposure. . However, it is rare that the amount of light of the subject suddenly increases during exposure, except when performing flash photography. Thus, as in the case of the aperture control circuit shown in FIG.
Only in that case, the diaphragm plate may be prevented from rotating. In addition, about the same member as the said 1st example,
Use the same code.

The aperture control circuit of this embodiment is obtained by removing the stop switch from the aperture control circuit of the first embodiment. For this reason, when the amount of light from the subject is sufficiently large to operate the switching transistor 74, the main switch 62
Is turned on, the solenoid 51 operates. And
Due to the action of the transistor 76, the solenoid 51 maintains its operating state even if the amount of light of the subject subsequently decreases and the base current supplied from the solar cell 26 decreases. According to this aperture control circuit, the structure can be further simplified. Therefore, it is suitable for a case where lower cost is required, such as when used in a film unit with a lens that does not include a flash device. In this case, the power battery 39
Are used exclusively for aperture control.

In the above example, the aperture plate is provided with one small aperture, but for example, a plurality of apertures may be provided in the aperture plate. Further, although the aperture opening is switched by rotating the aperture plate, this may be performed by sliding the aperture plate.

In the above embodiment, the diaphragm plate is moved by a solenoid. However, the diaphragm plate may not be moved by a solenoid. For example, an iron core may be provided in a part of the diaphragm plate, and the iron core may be attracted by an electromagnet. Alternatively, the diaphragm plate may be moved.

In the above example, the photometric means is constituted by a solar cell, but may not be a solar cell, and for example, a photoconductive element (cds) may be used. Furthermore, although the description has been made of the film unit with a lens, the invention may be applied to a compact camera.

[0042]

As has been described in detail above, the automatic exposure control apparatus according to the present invention has at least one aperture opening, a first position at which the aperture opening is inserted into a photographing optical path, An aperture plate movably provided between a second position where the aperture is retracted from the photographing optical path, and when the subject light amount is equal to or more than a predetermined value, the aperture plate is moved to the first position, and the object light amount is adjusted. Is less than or equal to a predetermined value, in the automatic exposure control device comprising a control unit that holds the second position,
A controller for driving the diaphragm plate; a main switch for turning on / off a power supply path to the driver in conjunction with half-pressing of a shutter button; A photometric unit, a switching unit that activates the driving unit when the light amount signal is equal to or more than a predetermined value, and a diaphragm plate that has moved to the first position before the start of exposure, when the subject light amount decreases during the exposure. But
Since the first holding means for holding the aperture plate at the first position is provided, even if the subject light amount decreases during the exposure,
The diaphragm plate can be prevented from moving.

Further, when the exposure is started in a state where the diaphragm plate is held at the second position, the diaphragm plate is held at the second position even if the amount of the subject increases during the exposure. Since the second holding means is provided, it is possible to prevent the diaphragm plate from moving even when the light amount of the subject decreases during the exposure. Further, since the film unit with lens of the present invention incorporates the above-mentioned automatic exposure control device, automatic exposure control can be performed with a simple structure.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an aperture control circuit of a first example.

FIG. 2 is an overall perspective view of a film unit with a lens.

FIG. 3 is an exploded perspective view of the film unit with a lens.

FIG. 4 is an exploded perspective view of an exposure unit in which an aperture plate is incorporated.

FIG. 5 is a perspective view showing an operation switch.

FIG. 6 is an explanatory diagram showing the operation of an operation switch.

FIG. 7 is an explanatory diagram showing operations of an aperture plate and an operation switch when the subject light is bright.

FIG. 8 is an explanatory diagram illustrating operations of an aperture plate and an operation switch when the subject light is dark.

FIG. 9 is a circuit diagram illustrating an aperture control circuit according to a second example.

[Explanation of symbols]

 26 solar cell 28 shutter button 28a pressing lever 47 aperture plate 51 solenoid 52 operation switch 56 kicking lever 62 main switch 63 stop switch

Claims (6)

[Claims] 1. At least one stop aperture is formed,
A first position in which the aperture opening is inserted on a photographing optical path;
An aperture plate movably provided between a second position at which the aperture opening is retracted from the photographing optical path, and when the subject light amount is equal to or more than a predetermined value, the aperture plate is moved to the first position; When the subject light amount is equal to or less than a predetermined value, in an automatic exposure control device including a control unit that holds the object at the second position, the control unit includes: a driving unit that drives the diaphragm plate; A main switch for turning on / off a power supply path to the driving means in conjunction therewith; a photometric means for outputting a light quantity signal corresponding to a subject light quantity; and a switching for activating the driving means when the light quantity signal is equal to or more than a predetermined value Means, the diaphragm moved to the first position before the start of exposure, even if the amount of light of the subject decreases during exposure,
An automatic exposure control device, comprising: first holding means for holding the aperture plate at the first position. 2. When the exposure is started in a state where the diaphragm plate is held at the second position, the diaphragm plate is held at the second position even if the amount of the subject increases during the exposure. An automatic exposure control device comprising a second holding unit. 3. The automatic exposure control device according to claim 2, further comprising a switch member in which the main switch and the stop switch are integrated, wherein the switch member has first to third elasticity. Three metal contact pieces, the first contact piece and the second contact piece when the shutter button is not pressed, and the second contact piece and the third contact piece And a holding portion that integrally holds one end of the second contact piece so that the first contact piece and the second contact piece are non-contact. And the third contact piece constitutes the main switch. When the shutter button is half-pressed, the second contact piece and the third contact piece come into contact with each other to turn on the main switch, and the shutter button When the button is fully pressed, the first contact piece and the second contact piece do not come into contact with each other. Wherein the stop switch is turned off. 4. The drive unit is constituted by a solenoid having a movable iron core, a groove is formed in an end of the iron core, and the groove is engaged with an interlocking pin provided on the aperture plate to thereby form the stop plate. 2. The method according to claim 1, wherein the moving is performed.
4. The automatic exposure control device according to any one of claims 3 to 3. 5. The automatic exposure control device according to claim 1, wherein said photometric unit is constituted by a solar cell. 6. A lens-equipped film unit pre-loaded with an unexposed photographic film, the lens-equipped film exposure unit comprising the automatic exposure control device according to claim 1.