JP2001337366A - Diaphragm switching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the coupling structure between a diaphragm plate and a solenoid. SOLUTION: A coupling plate 33 where a coupling lever 33a is formed is stuck to the movable diaphragm plate 31. A guide part 24b for a moving iron core 35 is provided at the outside part of the solenoid 24. An engaging hole 35b and a stopper part are provided on the iron core 35. The coupling lever 33a of the plate 31 is coupled with the engaging hole 35b of the iron core 35. A plunger 35 is pressed out by the energizing of a compression coil spring 36, and the stopper part is pressed on the guide part 24b. At such a time, the diaphragm aperture 31b of the plate 31 is held at a diaphragm position. When the solenoid 24 is driven, the plunger 35 is attracted by a specified amount. Thus, the plate 31 is turned and the aperture 31b is set at a retreat position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aperture switching device for a film unit with a lens and a simple camera.

[0002]

2. Description of the Related Art A film unit with a lens is provided by the present applicant as a simple camera which is widely used. Among the lens-fitted film units, one incorporating an automatic aperture switching mechanism has been proposed by the present applicant in Japanese Patent Application Laid-Open No. 9-5817.
The lens-equipped film unit with a built-in automatic aperture switching mechanism can switch the aperture in synchronization with the operation of a shutter button at the time of shutter release in accordance with the amount of external light at the time of shooting. In this automatic aperture switching device, aperture switching based on the amount of external light is performed in two stages.

[0003] In this automatic aperture switching measure, a method is used in which an aperture plate is rotated about one point in order to move an aperture opening into and out of the camera optical axis at an accurate position.
In order to perform a rotating operation, the diaphragm plate has a shape in which the distance from the rotation center to the operating point receiving the rotational force is shorter than the distance from the rotation center to the center of the diaphragm opening, thereby enabling high-speed switching. As a driving member for rotating this diaphragm plate,
A solenoid having a movable core is used. This solenoid has a structure in which a magnetic force is generated by energizing a coil to attract a movable iron core, and the operation of the movable iron core is linear.

[0004]

However, in the above-described aperture switching device, the operation trajectories of the solenoid driving iron core and the movable aperture plate are different from each other. When a force other than the linear direction acts on the movable iron core, there is no force for regulating the force. Further, there is a problem in that the suction time varies greatly due to play between the movable iron core and the guide groove due to the twisting force caused by the rotational movement of the aperture plate, and in the worst case, the suction is not performed. For this reason, a method in which a spring is provided for each of the movable iron core and the diaphragm plate and the diaphragm plate is independently rotated by the bias of the spring when the movable iron core is attracted to the solenoid body has to be used. When this method is used, there is a problem that the number of parts increases and the cost increases.

An object of the present invention is to provide an aperture switching device having a simple connection structure so that the aperture can be switched at a high speed even when the aperture switching mechanism has an integral interlocking structure.

[0006]

In order to achieve the above object, the aperture switching device of the present invention moves the movable core in a direction in which the movable core is drawn into the coil by the magnetization of the fixed core by energizing the coil. A solenoid in which the movable core moves in a direction protruding from the coil by the urging force of the return spring when cut off, and a solenoid that is rotatably mounted on a plane perpendicular to the imaging optical axis and crosses the imaging optical axis by moving the movable iron core And a movable diaphragm plate for switching the diaphragm by rotating the movable diaphragm plate in such a manner that one end of the movable diaphragm plate is directly engaged with the movable core in both moving directions of the movable core.

Further, a guide member having a hole through which the movable iron core penetrates is fixed to the solenoid at a position away from one end surface of the coil in a direction in which the movable iron core projects, and the outer periphery of the movable iron core and the inner periphery of the hole are fixed. The movable core is guided in the projecting direction by guiding the movement of the movable core by sliding contact with the movable core and by making a stopper member protruding from the outer periphery of the movable core abut around the hole of the guide member. Preferably. Further, when the movable iron core moves to the projecting position, a small aperture opening formed in the movable diaphragm plate is inserted into the photographing optical axis, and the movable iron core moves to the retracted position, thereby moving the movable diaphragm plate to the photographing optical axis. It is preferable to switch from the top to the open stop.

Further, an engaging pin is integrally provided at one end of the movable diaphragm plate, and a pair of holding members for holding the pin from both sides in the moving direction are fixed to the movable iron core. Preferably, the light is transmitted to the movable diaphragm plate via the holding member. Further, a pin protrudes from the outer periphery of the movable core, and the pin penetrates a slot formed in the guide member to be elongated in the moving direction of the movable core, and engages with an elongated hole formed in the movable diaphragm plate, thereby moving the movable core. Is transmitted to the movable diaphragm plate via the pin.

[0009]

FIG. 2 is a schematic view showing the appearance of a film unit with a lens embodying the present invention. On the front surface of the lens-fitted film unit 2, a finder objective window 3, a photographing window exposing a photographing lens 4, a strobe light emitting section 5, a photodiode 6, and a strobe charge button 7 are formed. A film counter plate 8 and a shutter button 9 are formed on the upper surface of the lens-fitted film unit 2.
A winding knob 10 and a finder eyepiece window are exposed on the back of the film unit 2 with a lens.

As shown in FIG. 3, the lens-fitted photo film unit 2 comprises a main body base 11 and a front cover 12 and a rear cover 13 which are put on the front and rear of the main body. An exposure device 18 is provided at the center of the main body base 11,
The flash device 19 is attached to the right side of the camera as viewed from the front by nail coupling.

[0011] Cartridge 14 and film roll 15
a is a cartridge storage chamber 1 formed in the main body base 11;
6 and the film accommodating chamber 17 are incorporated when the film unit with lens 2 is manufactured. Rear cover 13
Bottom lids 13a and 13b are formed integrally below the cartridge storage chamber 16 and the film storage chamber 17 so as to light-tightly cover the bottom openings. The bottom cover 13a is opened when taking out the cartridge 14 in which the photographed film 15 has been taken.

The winding knob 10 is provided in the cartridge storage chamber 1.
6 attached to the upper part. A winding shaft formed integrally with the winding knob 10 is engaged with a spool of the cartridge 14. By rotating the winding knob 10, the photographed film 15 is wound into the cartridge 14 one frame at a time.

The strobe device 19 includes a printed circuit board 20,
Main capacitor 21, trigger switch 22, strobe charging switch 23, solenoid 24, strobe light emitting unit 5
Etc. are unit components integrally attached. The printed circuit board 20 is provided with a detection circuit for detecting the amount of external light by the photodiode 6, a drive circuit for driving the solenoid 24 according to the detected value, and the like.

As shown in FIG. 4, the exposure device 18 is mounted on a dark box base 25 which is formed in a rectangular cylindrical shape so as to protrude toward the front of the main body base 11 and serves as a base. On the front surface of the dark box base 25, a shutter opening 26 is formed. Further, a shutter blade 27 and a lens holder 28 are incorporated on the front surface of the dark box base 25. When the shutter button 7 is pressed down, the shutter blades 27 are rotated, and the subject light is guided to the shutter opening 26 through the aperture plate to perform photographing.

The shutter blade 27 is attached to a shaft 25a provided on the dark box base 25, and is rotatable around this portion. Also, the shutter blade 27
One end of the shutter blade 27 is connected to a spring member 29, and the shutter blade 27
It is held in the position to close.

FIG. 5 is a front view around the lens holder 28,
FIG. 1 is a schematic view showing a perspective view around a lens holder. A stop aperture 28a having a large aperture area is formed on the optical axis of the taking lens 4 of the lens holder 28. A cutout 28b is formed in a part of the lens holder 28. The distal end portion 31a of the movable diaphragm plate 31, which will be described later, enters the lens holder 28 via the notch 28b, and the diaphragm is switched.

The movable diaphragm plate 31 is made of a thin metal plate, and is formed substantially in an L-shape. This movable diaphragm plate 3
A connection plate 33 is attached to 1. This connecting plate 33
Is formed of a resin molded product having a connecting lever 33a and a mounting shaft hole 33b, and the movable diaphragm plate 31 is adhered to the back surface of the connecting plate 33. The connection lever 33a is connected to an engagement hole 35a formed in a movable iron core 35 of the solenoid 24 described later.

The tip 31a of the movable diaphragm plate 31 is
It is formed in an arc shape centering on the mounting shaft hole 33b, so that the distal end portion 31a can smoothly enter and exit from the notch 28b. An aperture 31b is formed in the tip 31a. The aperture 31b is formed by a hole having a smaller diameter than the aperture 28a formed in the lens holder 28. The movable diaphragm plate 31 is connected to the connecting lever 3.
The distance between 3a and the mounting shaft hole 33b is shorter than the distance between the mounting shaft hole 33b and the aperture 31b. The aperture opening 31a is provided between the aperture position and the retracted position.
In the case where the connection lever 33a is rotated around the center, the rotation trajectory of the connecting lever 33a is substantially straight.

The lens holder 2 is provided in the mounting shaft hole 33b.
The mounting pins formed to protrude from the back surface of 8 are inserted.
The diameter of the mounting pin is small, thereby reducing power loss when the movable diaphragm plate 31 rotates. Therefore, high-speed switching of the movable diaphragm plate 31 becomes possible.

The solenoid 24 is attached to the printed circuit board 20 of the strobe device 19 at a position close to the lens holder 28 as described above. Solenoid 24
Is composed of a solenoid body 24a, a movable iron core 35, and a compression coil spring 36. Also, the solenoid 24
Is provided with a guide portion 24b that supports the movable iron core 35 only in the movable direction. This guide part 24b is L
A support hole is formed on the protruding surface side of the movable iron core 35. The movable core 35 is inserted into this support hole regardless of whether the solenoid 24 is on or off.

The movable iron core 35 has an engagement hole 35a and a stopper 35b. The assembling connection lever 33a is engaged with the engagement hole 35a. By this engagement, the operation of the movable iron core can be transmitted to the movable aperture plate 31 without asobi. A stopper 35b having a circular cross section is fixed near the engagement hole 35a.
The outer diameter of the movable iron core 35 is larger than that of the movable iron core 35. The compression coil spring 36 urges the movable iron core 35 in a direction to protrude from the solenoid main body 24a. By the urging of the compression coil spring 36, the stopper 35b of the movable core 24 is pressed against and held by the guide 24b. At this time, the aperture 31b of the connected movable aperture plate 31 is
It is set to the aperture position. By pressing the stopper portion 35b against the guide portion 24b, the aperture opening 31 can be positioned at the aperture position outside the solenoid 24,
The position accuracy of the aperture position can be obtained.

The solenoid body 24a is mounted on the printed circuit board 2
It is turned on and off by a drive circuit provided at 0. The drive circuit controls on / off of the solenoid main body 24a based on a signal from a detection circuit for detecting the amount of external light. That is, when the solenoid 24 is turned on via the drive circuit according to the amount of external light detected from the photodiode 6, the solenoid body 24a is excited, and the movable iron core 35 is attracted by a predetermined amount. By this suction operation, the movable aperture plate 31 can be set from the aperture position to the retracted position, and can be held.

In this solenoid, if the moving distance is long, the suction force is reduced.
The moving amount of the movable iron core 35 of No. 4 is set to 2 mm or less.
For example, when the moving amount of the movable core 35 is 2 mm, the moving amount of the diaphragm opening 31b of the movable diaphragm plate 31 is 6 mm, and the distance from the rotation center of the movable diaphragm plate 31 to the center of the diaphragm opening 31b is 10 mm. The distance from the rotation center of the movable diaphragm plate 31 to the operating point (the center of the connecting lever) is set to 3.3 mm. When the moving distance is 1 mm, the distance from the rotation center of the movable diaphragm plate 31 to the operating point (the center of the connecting lever) can be set to 1.67 mm.

Hereinafter, the operation of the present embodiment will be described. At the time of non-shooting, as shown in FIG. 5, the urging force of the compression coil spring 36 causes the stopper 35b of the movable iron core 35 to move.
Is pressed against the guide portion 24b. At this time, the diaphragm opening 31b of the movable diaphragm plate 31 is held on the optical axis of the photographing lens 4.

When the shutter button 7 is pressed, the photodiode 6 detects the amount of external light. Photodiode 6
When the subject brightness is determined to be low based on the detection value of, the solenoid 24 is driven. At this time, as shown in FIG. 6, the movable iron core 35 of the solenoid 24 is
Is sucked into the body of the With this suction, the movable diaphragm plate 31 is set to the retracted position. At this time, the aperture is switched to the aperture opening 28a formed in the lens holder 28, and the aperture becomes large. When it is determined that the subject brightness is high, the solenoid 24 is not driven. For this reason, the diaphragm remains at the diaphragm opening 31b of the movable diaphragm plate 31 and enters a small diaphragm state.

As described above, by forming the movable diaphragm plate 31 and the solenoid 24 integrally and interlockingly, the diaphragm switching device can be simplified. Also, solenoid 2
By rotating the movable diaphragm plate with the urging force of the compression coil spring 36 provided in the actuator 4 and the attraction force of the solenoid 24 at the time of driving, the diaphragm switching device can be configured with a small number of components.

In the above-described embodiment, the connection lever 33a is formed in the movable aperture plate 31, the engagement hole 35a is formed in the movable iron core 35, and these are connected to perform aperture switching. May go. In this case, as shown in FIG.
0b. A connection lever 43a is formed on the movable core 43 at right angles to the axial direction. Further, a guide hole 42b for moving the connecting lever 43a between the throttle position and the retracted position is formed in the guide portion 42a of the solenoid 42. The guide hole 42b is formed as a long hole, and the length in the long axis direction corresponds to the movable length of the connecting lever 43a. Insert this connecting lever 43a into the guide hole 42b,
It is connected to the operation hole 40b and is moved. In this case, there is no need to provide a connecting plate on the movable diaphragm plate 40, the number of components can be reduced, and the drive iron core and the solenoid can be unitized.

Further, a connecting pin may be provided on the movable diaphragm plate, and an engaging member having an engaging groove formed in the movable iron core may be fixed. In this case, as shown in FIG. 8, an engagement member 52 having an engagement groove 51 formed in a part of the outer periphery is fixed to a driving iron core 53. At the time of assembly, the connecting pin 5 of the movable diaphragm plate 54 is
5 is engaged with the diaphragm opening 5 of the movable diaphragm plate 54.
6 is switched between the stop position and the retreat position. At this time, the urging of the spring 57 causes the engaging member 52 to be pressed against the guide portion 58a formed on the solenoid 58, thereby holding the aperture opening 56 at the aperture position.

In the above embodiment, the strobe substrate 2
Although the solenoid 24 is fixed to 0, the solenoid may be fixed to the base of the dark box instead. In this case, since the movable diaphragm plate and the solenoid are attached to the same member, the positioning accuracy of the parts can be improved.

In the above-described embodiment, the aperture switching device is provided in the film unit with a lens. However, the present invention may be applied to other compact cameras and the like.

[0031]

As described above, according to the aperture switching device of the present invention, the movable iron core moves in the direction of being drawn into the coil by the magnetization of the fixed iron core due to energization of the coil, and the return spring is released by cutting off the energization. A solenoid that moves in the direction that the movable core protrudes from the coil by the urging force, and is rotatably mounted in cotton perpendicular to the imaging optical axis, and is rotated by moving the movable core so as to cross the imaging optical axis and stop. And a movable diaphragm plate that switches between the movable iron cores.
Since one end of the movable diaphragm plate is directly engaged with the movable iron core, a simple structure with a small number of parts can be obtained.

A guide member having a hole through which the movable core penetrates is fixed to the solenoid at a position away from one end surface of the coil in the direction in which the movable core projects, and the outer periphery of the movable core and the inner periphery of the hole are fixed. The movable core is guided in the projecting direction by guiding the movement of the movable core by sliding contact with the movable core and by abutting a stopper member protruding from the outer periphery of the movable core around the hole of the guide member. With this configuration, the positional accuracy of the aperture can be reliably obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state of a main part of an aperture switching device embodying the present invention.

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

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

FIG. 4 is an exploded perspective view showing the exposure apparatus.

FIG. 5 is a front view of the aperture switching device at an aperture position.

FIG. 6 is a front view of the aperture switching device in a retracted position.

FIG. 7 is a perspective view in a second embodiment.

FIG. 8 is a perspective view in a third embodiment.

[Explanation of symbols]

 2 Film unit with lens 24, 42 Solenoid 24b, 42a Guide part 28 Lens holder 31, 40 Movable aperture plate 31b, 40c Aperture opening 33 Connecting plate 35, 43 Movable iron core 36 Compression coil spring 42b Guide hole

Claims (5)

[Claims] 1. A movable core moves in a direction to be drawn into a coil by magnetization of a fixed core by energizing the coil,
A solenoid in which the movable core moves in a direction protruding from the coil by the biasing force of the return spring when the power is cut off, and an imaging optical axis which is rotatably mounted on a plane perpendicular to the imaging optical axis and which is moved by the movable iron core A movable diaphragm plate for switching the diaphragm by rotating across the movable core, wherein one end of the movable diaphragm plate is directly engaged with the movable core with respect to both moving directions of the movable core. apparatus. 2. A guide member having a hole through which the movable iron core penetrates is fixed to the solenoid at a position away from one end surface of the coil in a direction in which the movable iron core projects, and the outer periphery of the movable iron core and the inner periphery of the hole are fixed. The movable core is guided in the projecting direction by guiding the movement of the movable core by sliding contact with the movable core and by making a stopper member protruding from the outer periphery of the movable core abut around the hole of the guide member. The aperture switching device according to claim 1, wherein the aperture is switched. 3. When the movable iron core moves to the projecting position, a small aperture opening formed in the movable aperture plate is inserted on the photographing optical axis, and the movable iron core moves to the retracted position, whereby the movable aperture plate moves. 3. The aperture switching device according to claim 1, wherein the aperture switching device is retracted from the photographing optical axis and switched to an open aperture. 4. An engaging pin is integrally provided on one end side of the movable diaphragm plate, and a pair of holding members for holding the pin from both sides in a moving direction of the movable iron core are fixed to the movable iron core. 4. The diaphragm switching device according to claim 3, wherein the light is transmitted to a movable diaphragm plate via a holding member. 5. A pin protrudes from an outer periphery of the movable core, and the pin penetrates a slot formed in the guide member in a moving direction of the movable core so as to engage with an elongated hole formed in a movable diaphragm plate. The aperture switching device according to claim 3, wherein the movement of the movable iron core is transmitted to the movable aperture plate via the pin.