Seikosha Co., Ltd.

Seiko Precision Inc.

Shigeru Tagami

Nobuo Shinozaki

Kazuo Akimoto

Kanji Ito

Katsuhiko Matsushita

Masuo Ogihara

Hiroshi Yamazaki

Youichi Seki

Masaki Tanaka

Shinji Nagaoka

Teruyo Hayakawa

Hiroyuki Ishida

Yoichi Seki

Tadashi Nakagawa

Hiroaki Ishida

Michio Kawai

Akihiro Ito

Tadashi Ishikawa

Yukio Morino

Seiichi Imano

Miyoshi Tanikawa

Atsushi Takami

Takahito Otora

Hiroto Tsuyuki

Yuji Nakajima

Tomihiko Aoyama

Katsuhito Niwa

Yoshio Umedu

Yoshio Umezu

Takayuki Sato

Katauhito Niwa

A rocking motor comprises a coil wound around a hollow coil bobbin. A rotor is rotatably mounted at a position close to an end portion of the coil bobbin. The rotor has a center shaft and a permanent magnet and is magnetized with two poles such that the positions of the poles are located close to the coil and the magnetization angle is greater than 90 degrees but less than 180 degrees. The positions of the poles of the rotor and the coil are adjacent to one another so that a rotary torque can be efficiently obtained by a magnetic force generated by the coil. The rocking motor can generate a high power output with a relatively low power supply and its operational performance is not adversely affected by an external magnetic field.

Rocking motor

A camera has a shutter which may also constitute a diaphragm. In a multi-flash mode the shutter selectively has a maximum aperture at an onset or at the end of the time base. The flash occurs in synchronism with a shutter waveform shaped by this aperture area and a time base element. In a second embodiment, a second diaphragm setting circuit is provided, in diaphragm priority photography, for computing a measurement value of a distance to a subject and a second diaphragm value from the guide number during an emission of flashed light. The diaphragm is set to the computed second diaphragm value, ad an electronic flash is energized with a desired aperture area. The diaphragm is set to an initial value to effect the photography at a time other than during the emission of flashed light. A timing circuit may be provided for setting the diaphragm to the second diaphragm value. The aperture area may be increased or decreased for diaphragm matching with the quantity of flashed light and the distance to the subject during diaphragm priority flash photography.

Flash synchronizing device

A camera shutter system includes a matrix memory, an arrangement for determining the initial speed of a shutter sector, and a source of exposure values. The memory stores shutter-exposure pulse data elements, and is addressed by functions of the determined speed and the exposure values. A motor coupled to the sector is controlled in response to an accessed pulse data element. The data elements may relate only to variable portions of movement of the shutter, and be added to fixed values in order to minimize the size of the memory.

Camera shutter

A camera shutter system has a motor driven sector for opening and closing a shutter opening. A photo-interruptor is positioned to intercept a light beam, to effect the outputting by the photo-interruptor of a signal pulse corresponding to the speed of the shutter. A memory storing exposure data, such as a matrix memory, is accessible as a function of the speed signal and an exposure quantity that is a function of the brightness of the brightness of an object to be photographed. The accessed exposure data is modified as a function of an observed exposure quantity.

Arrangement for compensating for variable speed of a camera shutter

A camera shutter system has a motor driven sector for opening and closing a shutter opening. A photo-interruptor is positioned to intercept a light beam, to effect the generation of a photo-interruptor signal. A timer has a counter that is set to a first count in response to the photo-interruptor signal, and is reset when a given count is reached. A shutter malfunction signal is generated when the level of the photo-interruptor signal has not changed by the time the given count is reached.

A camera shutter system has a motor driven sector for opening and closing a shutter opening. A photo-interruptor is positioned to intercept a light beam, to effect the sequential generation of first and second photo-interruptor signal pulses, the first pulse having a width that is a function of the speed of the sector. A timer has a counter that is set to a first count corresponding to an exposure value that is a function of the brightness of an object to be photographed and the width of the first photo-interruptor signal. The timer is controlled to count down in response to the second photo-interruptor signal, and the sector driving motor is energized during the count down of the timer.

A camera shutter of the type in which a shutter blade is initially displaced from an open position, in which a shutter opening is open, to a closed position, in which the shutter opening is closed, prior to the exposure-taking operation includes an actuating member displaceable in shutter-opening and shutter-closing directions to actuate the shutter blade in opening and closing directions. A drive motor effects displacement of the actuating member in the shutter-opening and shutter-closing directions, and a biasing spring biases the actuating member in the shutter-opening direction thereby preventing accidental closing of the shutter blade in the event impacts are applied to the camera. A detection switch detects when the shutter blade is in the open position, the switch being responsive to displacement of the actuating member in the shutter-opening direction to detect the open position of the shutter opening.

Shutter for a single lens reflex camera

A program shutter for automatic exposure control including a forwardly/reversibly rotatable step motor for opening and closing a shutter to effect automatic exposure in the control circuit for controlling the operation of the step motor. The control circuit includes stored predetermined shutter mechanism characteristic values. The reversible stepping motor varies the lens aperture in response to a pulsed lens control signal generated by the control circuit. The corresponding value associated with each pulse is varied to be synchronized with and dependent on the shutter mechanism characteristic values and correspondingly varies the rotational power of the reversible stepping motor to overcome detrimental inherent shutter mechanism characteristics and to increase the response efficiency of the shutter.

Program shutter

A small stepping motor has a rotor comprised of a rotatably mounted and radially magnetized permanent magnet having a plurality of magnetic poles, a stator having a plurality of magnetic pole portions positioned to face the rotor, a coil wound around the stator, and a driving circuit for controlling the exciting current supplied to the coil. A leakage flux converging member is positioned in the vicinity of the stator so that leakage magnetic flux from the stator or the coil is converged by the leakage flux converging member so as to pass through the stator.

Small stepping motor

A drive ring drivable by a stepping motor is normally urged by a spring to turn in one direction around a lens aperture. When not in use, the stepping motor is not subjected to the resilient force from the spring since the drive ring is locked against rotation by a ratchet wheel engaged by an engagement lever. The stepping motor is therefore not subjected to undue stresses and is prevented from malfunctioning. Consequently, focusing failures and exposure adjustment failures which could otherwise arise from malfunctioning of the stepping motor are prevented from occurring. In operation, a solenoid is energized to move the engagement lever out of engagement with the ratchet wheel, which is then freed to allow the drive ring to be turned by the stepping motor.

Motor-driven shutter for camera

A method of driving a motor-driven shutter for a camera having a sector opening lever which is pivotal to open and close sectors, a sector opening cam movably supported and engageable with an engagement pin provided on the sector opening lever, an actuating member for pivoting the sector opening lever through engagement between the sector opening cam and the engagement pin, and a reversible motor for driving the actuating member. The motor is temporarily suspended when the actuating member is driven to a position where the sector opening cam comes into contact with the engagement pin, and the motor is restarted to cause the engagement pin to reach a predetermined position on the sector opening cam. Thus, it is possible to obtain a stable shutter opening operation and hence increase the degree of aperture accuracy.

Method of driving a motor-driven shutter for a camera

In a camera having a lens shutter and a focal-plane shutter accomplishing the operations of programed exposure and aperture control, a flash photography changeover device includes a first changeover circuit for setting a lens shutter mode for operating the lens shutter as a programed shutter or a focal-plane shutter mode for controlling the shutter speed by the focal-plane shutter and the aperture by the lens shutter; a first driving device for controlling the programed exposure value and/or the aperture value of the lens shutter; a second driving device for controlling the shutter speed of the focal-plane shutter; a sequence control circuit for controlling the operating timings of the two driving devices; a setting circuit for selecting and setting automatic exposures with a natural light and a flash light; and a coercive changeover circuit for setting the lens shutter mode irrespective of the setting of the first changeover circuit when the setting circuit is set to the automatic exposure with the flash light. The setting circuit and the coercive changeover circuit may be replaced by a determining circuit for detecting and determining a limit shutter speed at which the focal-plane shutter is synchronized with the flash light; and a coercive changeover circuit for setting the lens shutter mode irrespective of the setting of the first changeover circuit for setting the shutter mode, when the determining circuit determines that the shutter speed exceeds the limit speed.

Flash photography changeover device

A camera shutter has an automatic focusing lens operative when actuated to effect an automatic focusing operation. An actuating ring is normally placed in a non-operating region and momentarily shifted to an operating region during the automatic focusing operation. The actuating ring is sequentially displaceable in forward and reverse direction through the operating region to actuate the automatic focusing lens, and displaceable in the forward and reverse directions in the non-operating region without effecting actuation of the automatic focusing lens. A ratchet mechanism is coupled to the actuating ring for selectively locking and unlocking the actuating ring in the non-operating region in response to the displacement thereof in the forward and reverse directions. A bi-directionally rotatable stepping motor is connected to drive the actuating ring to displace the same in the forward and reverse directions.

There is disclosed a program shutter for use in a camera. The program shutter consists of a shutter mechanism and a control portion. The shutter mechanism has sectors for defining an opening and a stepper motor for driving the sectors. The control portion produces pulses having pulse width conforming to the operating characteristic of the shutter mechanism. These pulses are used to step the motor forward or backward according to the exposure corresponding to the luminance of the subject.

A program shutter has a plurality of shutter sectors driven in opening and closing directions by a reversible stepping motor to define a lens aperture during an exposure operation. An arithmetic circuit calculates an exposure amount corresponding to the brightness of the object being photographed, and a counting circuit outputs a pulse count corresponding to the number of steps through which the stepping motor should be rotated based on the calculated exposure amount. A pulse circuit produces driving pulses equal in number to the number of steps determined by the counting circuit, and a time circuit determines the ON/OFF periods of the driving pulses based on the calculated exposure amount. The driving pulses are applied to the stepping motor through a driving circuit to accordingly drive the shutter sectors in the opening and closing directions during the exposure operation.

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Chiba, Japan

Shigeru Tagami