JP2002099065A - Film unit with lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a strobe switch from a film unit with lens provided with a protecting cover. SOLUTION: The film unit with lens is provided with the protecting cover which protects an imaging lens from scratches and stains. The operation of opening and closing the protecting cover is linked to the operation of turning a charging switch 22 on and off. During the protecting cover closed, the charging switch 22 is at the off position. When the protecting cover opened, the charging switch 22 is turned on. When the charging switch 22 is turned on, a main capacitor 23 and a trigger capacitor 27 start to be charged. During the protection cover opened, a gate voltage of a thyristor 29 varies due to a variation of resistance of a CdS 6 in response to subject brightness. If the subject brightness is high, the thyristor 29 is cut off and the trigger capacitor 27 is not discharged even if a synchronized switch 21 is closed. If the subject brightness is low, the thyristor 29 is conducting and the trigger capacitor 27 can be discharged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film unit with a lens provided with a protective cover for protecting a photographic lens from dust and dirt. More specifically, the opening / closing operation of the protective cover and the charging operation of a strobe light are linked. The present invention relates to a lens-equipped film unit in which a photographer does not need to determine whether or not photographing is necessary.

[0002]

2. Description of the Related Art A film unit with a lens manufactured and sold by the present applicant can take a photograph at the place where it was purchased. It is now widely used because it is easy to obtain. The lens-equipped film unit does not require cumbersome work such as loading or rewinding the film, and can be easily operated by a user unfamiliar with photography.

[0003] A film unit with a lens has a protective cover that covers the taking lens when not in use so that it can be easily carried so that the taking lens exposed on the front surface is not stained or scratched. Are known.
The protective cover is engaged with two grooves formed above and below the front surface of the film unit with a lens, and slides left and right between a closed position for covering the taking lens and an open position for exposing the taking lens. It can be easily opened and closed.

[0004] The film unit with a lens includes:
Some cameras have a built-in strobe device so that they can be used indoors or at night. To perform flash photography, turn on the flash switch that is exposed on the outer surface of the film unit with a lens, and the charge switch turns on.After a while, the light-emitting element that indicates the completion of charging lights up. When you press, the flash fires simultaneously with the exposure of the film.

A strobe device used for a film unit with a lens has a simple structure in which a strobe substrate on which basic components of a strobe circuit are mounted and a strobe light emitting tube and a power supply battery are held as a unit. The circuit includes a charging circuit having a charging switch for charging a trigger capacitor and a main capacitor via a boosting oscillation circuit connected to a power supply battery, and a trigger circuit for performing a trigger discharge for inducing strobe light emission. Is provided.

[0006]

In a film unit with a lens provided with both a protective cover and a strobe device as described above, when performing flash photography, the protective cover is opened to expose the photographic lens, and then the flash is exposed. Since the switch must be turned on, this operation is troublesome for a photographer who does not normally touch the camera at all, and sometimes the user accidentally forgets to turn on the strobe switch just by opening the protective cover. In addition, users who are unfamiliar with shooting often wonder whether or not to use flash photography depending on the weather and shooting location, and that overexposure or underexposure can not take high quality photos. was there.

[0007] JP-A-2000-137271 discloses that
It describes a film unit with a lens that does not emit strobe light if the subject brightness is high even when the strobe switch is turned on. In the flash unit of the film unit with the lens, a semiconductor switching element such as a thyristor is connected in a trigger circuit loop including a synchro switch that contacts in synchronization with opening of a shutter blade,
The voltage applied to the gate of the thyristor connected between the reference resistance element and the photoconductive element, utilizing the fact that the electric resistance of the photoconductive element such as CdS or photodiode varies according to the amount of received light. From the difference, when the amount of light received by the photoconductive element is high, the thyristor is turned off, strobe light emission is prohibited so that trigger discharge does not occur,
The battery is not wasted, and over-exposure shooting is prevented.

In Japanese Patent Application Laid-Open No. 2000-81662, sliding operation of a strobe switch and switching of large and small apertures are interlocked, and a non-photographing position, a large aperture with strobe charging ON, and a small aperture with strobe charging ON are provided in three stages. It describes a film unit with a lens that enables setting of shooting conditions. In this film unit with a lens, by providing a dimming member using a photochromic material in the finder field of view, the subject brightness serving as a criterion for switching the aperture can be displayed to the photographer, or the subject brightness measured using CdS can be displayed. The on / off of the thyristor provided in the trigger circuit can be controlled accordingly, preventing strobe light emission when the subject brightness is high, suppressing unnecessary consumption of batteries and avoiding overexposure shooting. Like that.

However, the film units with lenses described in the above two publications rely on the photographer to decide whether or not to perform flash photography, and a flash switch provided on the outer surface of the film unit with lenses is required. Because of the necessity of operation, as described above, it is not possible to solve the problems such as trouble for a user unfamiliar with shooting and forgetting to turn on a strobe switch.

The present invention has been made in view of solving the above problems, and eliminates the use of a strobe switch provided on the outer surface of a film unit with a lens, so that the photographer does not judge whether or not strobe shooting is necessary. It is an object of the present invention to provide a lens-fitted film unit.

[0011]

In order to achieve the above object, in the film unit with a lens according to the present invention, the opening / closing operation of the protective cover for protecting the lens from scratches and dirt is performed in conjunction with the strobe charging. The strobe charging is always performed when the protective cover is at the open position, and the strobe charging is stopped when the protective cover reaches the closed position.

In order to adopt such a configuration, a switch for preventing the trigger circuit from operating even when the synchro switch is turned on is provided in order to prevent flash emission when the subject brightness is high and flash photography is not necessary. is necessary. Specifically, CdS whose electrical characteristics change depending on the amount of received light
And a photoconductive element such as a photodiode and a semiconductor switching element such as a thyristor or a transistor can be used in combination. Thereby, the subject brightness is always measured, and when the subject brightness is high, the semiconductor switching element is turned off so that the trigger capacitor is not discharged, and when the subject brightness is low, the semiconductor switching element is turned on. By doing so, the synchro switch can be brought into contact with the shutter blade at the same time as the shutter blade is opened, and the trigger capacitor can be discharged.

[0013] Further, in providing the strobe device having the above configuration, the photographer is informed of whether the semiconductor switching element is in a conductive state or in a cut-off state, and in order to know whether or not the strobe emits light, It is preferable to provide a light emitting body that indicates each state of the semiconductor switching element.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a film unit with a lens according to the present invention will be described with reference to FIGS. The lens-equipped film unit 1 has a structure in which a camera body in which a photographing mechanism is incorporated is sandwiched between a plastic front cover 2a and a rear cover 2b serving as a body 2. On the upper surface of the body 2, a release button 3 and a transparent counter window 4 on which a counter plate indicating the number of shots are displayed are provided. A photographic lens 5 and CdS 6 are exposed on the front surface of the body 2, and a finder window 7 for exposing the finder lens is formed above the photographic lens 5.

The protective cover 8 is engaged with a groove provided above the finder window 7 and below the photographing lens 5 to open the photographing lens 5, the CdS 6 and the finder lens (see FIG. 1). And a closed position (see FIG. 2) for covering them in a concealable manner. Although not shown, a mark indicating a position where the protective cover 8 is completely closed and a position where the protective cover 8 is completely opened, and a click engaging portion at each position are provided in a groove portion where the protective cover 8 is engaged. Small projections are provided to allow the stop. A label serving as an exterior is attached to each of the body 2 and the protective cover 8. Note that the strobe light emitting section 9 is provided at a position not covered by the protective cover 8.

As shown in FIG. 3, the protective cover 8 is formed with a finger-holding projection 8a for facilitating the sliding operation. Above it, a lock member 9 for locking the release button 3 is engaged. Elongated cam groove 8 with step
b is formed. Also, on the side edge of the protective cover 8,
When the protection cover 8 is in the closed position, the projection 8c is formed into the engagement hole 10 of the front cover 2a. When the lock member 9 is fitted on a shaft formed on the front cover 2a, the lock member 9 moves up and down along the cam groove 8b during sliding movement of the protection cover 8, and when the protection cover 8 is at the closed position,
The pressing rod 3a connected to the release button 3 is fixed, and the shutter release is locked. When the protective cover 8 is in the open position, the lock is released to enable the shutter release.

A camera lens 12 is held at the center of the camera body 12, and a shutter device for kicking a shutter blade provided on the back of the camera lens 5 to perform exposure and rotating a winding knob 13 are provided. A shutter charge mechanism for generating a kicking force for kicking the shutter blades. On both left and right sides of the camera body 12, a cartridge storage chamber 14 containing a film cartridge in which a film winding spool is engaged with a shaft of a winding knob 13, a film is previously extracted from the film cartridge, and is wound into a roll. A film roll storage chamber 15 containing the rolled film rolls is provided.

The wind-up knob 13 is partially exposed from the rear cover 2b. When the wind-up knob 13 is rotated each time a picture is taken, it moves the exposed film frame toward the film cartridge and rotates it. A shutter charge is performed in accordance with the operation to prepare for the next photographing.

The strobe unit 16 is brought into contact with a strobe board 20 to which a light emitting portion 17 in which a strobe discharge tube is disposed and a battery contact piece 19 holding a power battery 18 are fixed with the opening of a shutter blade, and is turned on. Various components for a flash circuit are mounted, such as a synchro switch 21, a strobe charge switch 22, and a main capacitor 23 charged for strobe discharge. The CdS 6 is disposed on such a strobe substrate 20, and when the strobe unit 16 is attached with the claw portion 24 formed on the camera body 12, the front cover 2 a is covered, and as shown in FIG. Together with the front of the body 2.

As shown in FIG. 4B, when the protective cover 8 is in the closed position, the projection 8c formed on the protective cover 8 is provided on the charging switch 22 provided on the strobe substrate 20. The charging switch 22 is turned off through the engagement hole 10 between the contact pieces of the charging switch 22. On the other hand, when the protective cover 8 is opened, FIG.
As shown in FIG.
, The charging switch 22 is turned on. When the charge switch 22 is turned on, the main capacitor 2
The charging of 3 starts, which will be described in detail with reference to FIG. 5 which shows a circuit diagram of a strobe circuit provided on the strobe unit 16.

As shown in FIG. 5, the strobe circuit used in the present invention includes a transformer 25 including a primary coil 25a, a secondary coil 25b, and a tertiary coil 25c connected from a power supply battery 18 and a charging switch 22, and a transistor 26. A charging circuit for charging the main capacitor 23 and the trigger capacitor 27 via the provided booster oscillation circuit, a trigger circuit including the trigger capacitor 27 and the trigger coil 28, a synchro switch 21 and a thyristor 29, and a gate connected to the thyristor 28 And a photometric circuit having CdS6.

When the protection cover 8 is in the closed position, that is, when the charging switch 22 is off, charging is not performed.
When the protection cover 8 is opened, that is, when the charge switch 22 is turned on, the main battery 23
Then, charging of the trigger capacitor 27 is started. When the charging switch 22 is closed, a voltage is applied from the power supply battery 18 to the primary coil 25a, the tertiary coil 25c, and the resistor 30.

The voltage applied to the tertiary coil 25c is applied to the base side of the transistor 26 via the resistors 31 and 32, so that the transistor 26 is turned on and the primary coil 2c is turned on.
A primary current starts flowing from 5a toward the emitter side of the transistor 26. At the beginning of the current flow, an electromotive force is generated in the secondary coil 25b according to the winding ratio with the primary coil 25a with the gradually increasing current. The secondary current flows due to the electromotive force generated in the secondary coil 25b, passes through the rectifying diode 33, and
3 and the trigger capacitor 27 are charged. The resistor 34 includes the main capacitor 23 and the trigger capacitor 2.
7 is for adjusting the magnitude of the secondary current flowing through each of them.

The tertiary coil 25c generates an electromotive force at the start of the flow of the secondary current, and increases the base current of the transistor 26. Therefore, the current flowing between the emitter and the collector also increases. Secondary current continues to flow. Eventually, when the transistor 26 reaches a saturation state, the primary current does not increase, so that the secondary current decreases.
At this time, a voltage in the reverse direction is applied to the base side of the transistor 26, and the transistor 2
6 turns off and the primary current stops. Eventually, when the voltage applied to the base side of the transistor 26 in the reverse direction disappears, the primary current starts flowing again.

As described above, the high voltage pulse is repeatedly oscillated from the boosting oscillation circuit, and the main capacitor 23 and the trigger capacitor 27 are charged. When each capacitor approaches the completion of charging, a current flows through the light emitting diode 35, and the light emitting diode 35 starts lighting. The light of the light emitting diode 35 can be seen from a confirmation window (not shown) formed in the body 2 so that the photographer can know that the charging is completed.

When charging is completed and the release button 3 is pressed, the shutter blades are opened and the synchro switch 21 is closed. At this time, if the subject brightness is high, Cd
Since the resistance value of S6 is reduced, the voltage applied to the gate of the thyristor 29 is reduced, the thyristor 29 is kept off and the cut-off state is maintained, the trigger capacitor 27 is not discharged, and the strobe discharge tube 36 emits light. And the film is exposed.

On the other hand, when the object brightness is low, the resistance 30
And the voltage ratio applied to the gate of the thyristor 29 increases. Then, the thyristor 29 is turned on and becomes conductive, the shutter blades are fully opened, and at the same time, the synchro switch 21 contacts and the trigger circuit is closed, so that the trigger capacitor 27 is discharged. When the electric charge released from the trigger capacitor 27 flows through the primary coil of the trigger transformer 28, a high voltage electromotive force is generated in the secondary coil. Then, a high voltage is applied to the trigger electrode 37, the insulation of the strobe discharge tube 36 is broken, the main capacitor 23 is discharged, and the strobe discharge tube 36 emits strobe light.

Accordingly, since the strobe light is emitted in synchronization with the opening of the shutter blade, strobe photography can be performed. As long as the charge switch 22 is closed, that is, as long as the protective cover 8 is open, the power meter 18
, The on / off control of the thyristor 29 by the CdS 6 is always performed, and the charging after the flash photography is performed again. In addition, when the charging of the main capacitor 23 and the trigger capacitor 27 is completed, when the protection cover 8 is closed, the release lock is performed by the lock member 9 engaged with the cam groove 8 b of the protection cover 8. Therefore, the flash does not accidentally emit light without closing the synchro switch 21.

Next, in the strobe device used in the above embodiment, the light metering circuit provided with a light emitting element for indicating whether the semiconductor switching element is in a conductive state or a cutoff state will be described.
This will be described with reference to the circuit diagram shown in FIG. Note that components that perform the same operations as in the previous embodiment are denoted by the same reference numerals.

The strobe circuit shown in FIG. 6 includes light emitting diodes 38 and 39 and resistors 40 and 4 in the photometric circuit shown in FIG.
1, 42 and 43 and transistors 44 and 45 are additionally provided. The transistor 44 uses an npn type, and the transistor 45 uses a pnp type. In this strobe circuit, when the subject brightness is high, the resistance value of CdS6 decreases,
Since the voltage applied to the bases of the transistors 44 and 45 decreases, the transistor 44 is turned off and the transistor 45 is turned on. On the other hand, when the subject brightness is low, the opposite is true, the resistance value of CdS6 increases, and the transistor 44 is turned on and the transistor 45 is turned off.

When the charging switch 22 is brought into contact with the strobe device having such a circuit configuration, the primary current flows and the light emitting diode 39 is turned on when the subject brightness is high, and the light emitting diode 38 is turned on when the subject brightness is low. . In other words, the light emitting diode 38 is turned on when strobe light is emitted, and the light emitting diode 39 is turned on when no strobe light is emitted. Green when strobe light is used,
When strobe light is not emitted, red light is turned on. The resistors 40 and 43 are connected to the transistor 4
The resistors 41 and 42 are provided for adjusting the voltage applied between the collector and the emitter of the transistors 45 and 45, and adjust the current flowing to the bases of the transistors 44 and 45.

In the film unit with a lens provided with such a strobe circuit, in addition to the window for confirming the lighting of the light emitting diode 35 for notifying the completion of the strobe charging on its outer surface, the window for confirming the lighting of the light emitting diodes 38 and 39. Is preferably formed so that the photographer can easily confirm these lights.

The film unit with a lens according to the present invention is not limited to the above embodiment. For example, a strobe charge switch exposes metal contacts on the front of the film unit with a lens, and also provides metal contacts on the protective cover side, and the metal contacts come in contact with the sliding movement of the protective cover to charge. May be performed. In addition to the light-emitting diodes that emit red and green light, the light-emitting elements that display the level of the subject brightness may use light that emits light of other colors, or may be formed on the outer surface of the film unit with a lens for confirming lighting. A color filter may be provided in the window so that the emission colors can be distinguished. Further, the protective cover is not limited to a form capable of sliding movement. For example, the present invention is equally applicable to a device having a rotatable protective cover having one end pivotally mounted.

[0034]

As described above, according to the film unit with the lens of the present invention, the strobe switch exposed on the outer surface of the unit is eliminated, the strobe charging is performed by opening / closing the protection cover, and the subject is charged. The photoconductive element that measures the brightness controls the semiconductor switching element provided in the trigger circuit loop, eliminating the need for the photographer to operate the strobe switch separately, and always shooting with the appropriate exposure. Can be easily done.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a state in which a protective cover is opened in a film unit with a lens according to the present invention.

FIG. 2 is a diagram illustrating a state in which a protective cover is closed in the film unit with a lens according to the present invention.

FIG. 3 is an exploded view of the film unit with a lens according to the present invention.

FIG. 4 is a diagram illustrating a state around a charge switch of a strobe device in the film unit with a lens according to the present invention.

FIG. 5 is a flash circuit diagram of the film unit with a lens according to the present invention.

FIG. 6 is a flash circuit diagram in which a light emitting element for checking flash light emission is added.

[Explanation of symbols]

 Reference Signs List 1 Film unit with lens 6 CdS 8 Protective cover 8b Cam groove 8c Projection 9 Lock member 10 Engagement hole 16 Strobe unit 20 Strobe board 21 Synchro switch 22 Charging switch 23 Main capacitor 27 Trigger capacitor 29 Thyristor 35, 38, 39 Light emitting diode

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G03B 15/05 G03B 15/05 17/02 17/02 17/04 17/04 F term (Reference) 2H002 AB06 DB25 HA11 2H053 AC22 BA02 BA23 CA41 2H083 CC06 CC23 CC48 CC52 2H100 AA61 2H101 AA01 BB05 BB08

Claims (2)

[Claims] A protective cover for opening and closing a photographing lens is provided. In response to opening and closing of the protective cover, a charge switch of a strobe device is turned on to charge a trigger condenser and a main condenser, and to open a shutter blade. In a film unit with a lens that turns on the synchro switch and discharges the trigger capacitor and main capacitor to emit light from the strobe discharge tube in synchronism, power is supplied in conjunction with the opening of the protective cover and the brightness of the subject is measured. And a semiconductor switching element that is provided in a discharge circuit loop of the trigger capacitor, and is turned off when the subject brightness is equal to or higher than a predetermined level, and is turned on when the subject brightness is lower than the predetermined level. Film unit with lens. 2. The film unit with a lens according to claim 1, wherein the photometric circuit includes a light emitting element for displaying whether or not the measured subject luminance is equal to or higher than a predetermined level.