Fuji Photo Film Company, Limited

Yukitsugu Hata

Junichi Takagi

Keiji Uchiyama

Katsumi Motomura

Kazuo Kamata

Nobuyuki Kameyama

Takashi Imamura

Mitsuyoshi Mochida

Makoto Isozaki

Kazumi Koike

Sumio Yoshikawa

Mitsuhiro Moriya

Kuniharu Kitagawa

Hirokazu Yokoo

Kazuo Okoyama

Masato Kagaya

A lens-fitted photo film unit includes a flash emitter for emitting flash light toward a photographic object in flash photography. A flash amount control circuit quenches flash emission of the flash emitter when a value of integration of light reflected by the object as measured by a first sensor in the flash photography comes up to a predetermined level. An aperture stop device designates one of a large aperture state and a small aperture state. A switch disables the flash amount control circuit if the small aperture state is designated, and enables the flash amount control circuit if the large aperture state is designated. The switch regulates operation of the flash amount control circuit in order to raise an amount of the flash light at a time of the flash photography in the small aperture state.

Lens-fitted photo film unit with electronic flash device

A lens-fitted photo film unit includes a photo film housing. A photo film roll chamber is formed in the photo film housing and pre-loaded with photo film in a roll form. A cassette holder chamber incorporates a photo film cassette, to wind the photo film therein after being exposed. A flash-emission main capacitor stores charge by a charging operation. A flash discharge tube emits flash light by a discharging operation of the charge. A flash circuit controls the main capacitor and the flash discharge tube for effecting the charging operation and the discharging operation. An EEPROM is incorporated in the photo film cassette. A write control IC is incorporated in the photo film housing, for writing information to EEPROM. A battery supplies the flash circuit and the write control IC with power. A charge control signal generator or BUSY terminal is disposed in the write control IC, and supplies the flash circuit with a low-level inhibit signal, to inhibit the flash circuit from effecting the charging operation. The write control IC controls the charge control signal generator, to write the information while the flash circuit is inhibited from effecting the charging operation. A power source voltage of the battery is prevented from dropping while the information is written.

Lens-fitted photo film unit having IC

In a flash circuit of a flash device, a Zener diode ( ) is connected to a tap point ( ) located at an intermediate position of a secondary coil of an oscillation transformer ( ). The oscillation transformer ( ) and an oscillation transistor ( ) constitutes an oscillation circuit. A potential at the tap point ( ) changes proportionally to a voltage charged in a main capacitor ( ). When the main capacitor ( ) is charged up to a set voltage, the Zener diode ( ) conducts a Zener current, which activates a stopping transistor ( ) and thus deactivates the oscillation circuit. When a flash charge switch ( ) is turned on, an end of a light guide portion of a charge condition indicator ( ) protrudes out of a lens-fitted film unit. When the main capacitor ( ) is charged up to the set voltage, a light emission element starts lighting and the light from the light emission element is projected from the end of the light guide portion.

Flash unit

A photo diode and a resistor are connected to each other in series. A gate of a FET is connected to the connection of the photo diode and the resistor. When a photometry switch is turned on, the photo diode generates a photo current according to a subject brightness. A potential difference is generated between the both terminal of the resistor. When the subject brightness is less than a threshold level, the FET is not turned on because of low potential difference of the resistor. When a subject brightness is equal to or more than the threshold level, the FET is turned on because of high potential difference of the resistor. A first transistor turned to be in a state opposite to the FET and a second transistor turned on and off according the state of the first transistor are provided. When the FET is turned off, the second transistor is turned on, and a solenoid is powered. The solenoid moves a stop plate out of an optical axis such that an exposure is taken through a large stop opening. When the FET is turned on, the second transistor is turned off, so the solenoid is not driven. Since the stop plate is set on the optical axis, an exposure is taken through a stop-down opening.

Automatic exposure control device for a camera

In a flash circuit of a flash device, a Zener diode ( ) is connected to a tap point ( ) located at an intermediate position of a secondary coil of an oscillation transformer ( ). The oscillation transformer ( ) and an oscillation transistor ( ) constitutes an oscillation circuit. A potential at the tap point ( ) changes proportionally to a voltage charged in a main capacitor ( ). When the main capacitor ( ) is charged up to a set voltage, the Zener diode ( ) conducts a Zener current, which activates a stopping transistor ( ) and thus deactivates the oscillation circuit. When a flash charge switch ( ) is turned on, an end of a light guide portion of a charge condition indicator ( ) protrudes out of a lens-fitted film unit. When the main capacitor ( ) is charged up to the set voltage, a light emission element starts lighting, and the light from the light emission element is projected from the end of the light guide portion.

A lens-fitted film unit with an exposure mechanism which is equipped with a built-in flash and a pre-loaded film cartridge is provided with an IC memory in which exposure data is written, a write control IC operative to control writing data on an exposure in the IC memory, and a switch arrangement comprising a synchronizing switch which is actuated by a shutter blade of the exposure mechanism to cause the built-in flash to make a flash and an auxiliary switch which is actuated by operation of the shutter mechanism. The write control IC is actuated to control writing data on an exposure in the IC memory when at least one of the synchronizing and auxiliary switches is actuated during making the exposure. The built-in flash has a charge switch opetative to be turned on for charging a capacitor of the built-in flash and to remain turned on until turned off. The write control IC, which has a control terminal connected to the built-in flash and changeable between an interruption state in which charging the capacitor is interrupted and a permission state in which charging the capacitor is permitted turns the control terminal into the interruption state immediately after an exposure to write the exposure data in the IC memory during interruption of charging the built-in flash.

Lens-fitted film unit with IC memory and method of writing data in IC memory

An electronic flash device equipped with LED indicator for providing an indication of completion of charging a main capacitor and a circuit for lowering power consumption has a controlling transistor operative to control a base current of the oscillating transistor which increases or decreases a primary current flowing through a primary winding and to be turned conductive by a current supplied from a battery through a current limiting resistor to start supply of the base current of the oscillating transistor. A secondary current generated in a secondary winding increases the base current of the controlling transistor, which increases the base current of the oscillating transistor which is lowered by the current limiting resistor having a large resistance and is increased or decreased by the controlling transistor. The electronic flash device can lower the power consumption as compared to the conventional devices which use a tertiary winding to increase or decrease the base current of the oscillating transistor. A tertiary winding of the electronic flash device is solely used for turning on LED.

Electronic flash device for photographic camera

A switching circuit is connected to an oscillation transistor of a charging circuit of a flash device of a lens-fitted photo film unit, for turning on or off the oscillation transistor. When a rear cover of a unit body of the film unit is separated, a battery for supplying the flash device is disconnected from the flash device through an insulating plate that is provided on the front cover. Thereafter when the battery or a new battery is connected to the flash device, a clear circuit outputs a clear signal to the switching circuit and a restoring circuit to initialize these circuits. In the initialized position, the switching circuit turns off the oscillation transistor, and maintains this switching condition until a restore signal is applied from the restoring circuit. The restoring circuit outputs the restore signal only when a predetermined cancel signal is applied from an external device. As the cancel signal, a voltage signal with a predetermined voltage level and a pulse signal with a predetermined pulse number have to be concurrently inputted to the restoring circuit within a predetermined time period.

Device for preventing unauthorized recycling of lens-fitted photo film unit

A write control IC is incorporated in the photo film housing, for writing information to EEPROM. A battery supplies the flash circuit and the write control IC with power. A charge control signal generator or BUSY terminal is disposed in the write control IC, and supplies the flash circuit with a low-level inhibit signal, to inhibit the flash circuit from effecting the charging operation. The write control IC controls the charge control signal generator, to write the information while the flash circuit is inhibited from effecting the charging operation. A power source voltage of the battery is prevented from dropping while the information is written.

In a flash device, a three-terminal switch is provided for connecting or disconnecting between a secondary coil of an oscillating transformer and a base of an oscillating transistor, between the secondary coil of the oscillating transformer and a triggering capacitor, and between the triggering capacitor and a primary coil of a triggering transformer. When the three-terminal switch is turned on, a biasing current is supplied to the base of the oscillating transistor, so a current flows through a primary coil of the oscillating transformer, and a secondary current from the secondary coil of the oscillating transformer is supplied to the main capacitor through the three-terminal switch and a base-emitter circuit of the oscillating transistor, to charge the main capacitor. The secondary current is also supplied to the triggering capacitor through the three-terminal switch, to charge the triggering capacitor. When a triggering switch is turned on while the three-terminal switch is on, the triggering capacitor discharges current through the primary coil of the triggering transformer, generating a triggering voltage for a flash discharge tube. If the three-terminal switch is turned off, the biasing current and the secondary current are cut from the oscillating transistor, and the triggering capacitor cannot discharge.

Flash device

A lens-fitted photo film unit has an electronic flash device (11, 30; 115) with a printed circuit board (173). The flash device includes a flash-emitting section (6, 170) for emitting flash light toward a photographic field, and a main capacitor (31, 155) for storing charge to be discharged in the flash-emitting section. The printed circuit board converts a current of a battery (12, 127) into a current of high voltage to be supplied to the main capacitor. The printed circuit board has a transistor (13, Tr1) for oscillation. A primary winding (15) has one end connected to the battery, and another end connected to a collector of the transistor. A secondary winding (16) is combined in mutual induction with the primary winding, has one end connected to the main capacitor, and another end connected to a base of the transistor. A tertiary winding (17) is combined in mutual induction with the secondary winding, has one end connected to the battery, and another end connected to the base of the transistor. An LED (21, 180) has a cathode connected to the one end of the tertiary winding with the battery, and an anode connected to the another end of the tertiary winding opposite to the battery. The LED is driven to emit light in response to charging of the main capacitor at a predetermined level. In a preferred embodiment, the photo film unit is pre-loaded with photo film (123) having speed of ISO 800 or higher, to allow the main capacitor to have small capacitance adapted to the high speed of the photo film.

Lens-fitted photo film unit and electronic flash device for use therewith

A lens-fitted photo film unit contains a cartridge shell into which an IC memory is incorporated, and a roll of photo filmstrip having a magnetic recording layer. Unit ID data and date-of-manufacture data are written in the IC memory in the factory. A data recording circuit is provided on a flash circuit board. The data recording circuit is connected to the IC memory through a printed circuit board mounted to a cartridge chamber of the film unit. A finder mask and a photo sensor for detecting the position of the finder mask are mounted in the film unit. The photo sensor is connected to the data recording circuit, to write photographic data corresponding to the output of the photo sensor in the IC memory at each exposure. Before printing, the data written in the IC memory is read to be recorded on the magnetic recording layer of the photo filmstrip by use of an external recording device which is connectable to the IC memory through an interface terminal which is exposed to an exterior of the film unit.

Lens-fitted photo film unit and data recording method therefor

A flash circuit of a flash device for a camera or a lens-fitted photo film unit is provided with a Zener diode connected to a tap point located at an intermediate position of a secondary coil of an oscillation transformer, to tap out voltage that is proportional to but less than charge voltage in a main capacitor. When the main capacitor is charged up to a set voltage, the Zener diode conducts a Zener current, which deactivates an oscillation transistor through a stopping transistor.

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Kanagawa, Japan

Yukitsugu Hata