Electronic shutter for camera

Claim 2

An electronic shutter comprising: a main switch, an exposure time control electric circuit to be closed by the main switch and including a light measuring integration circuit operable in accordance with the brightness of the subject to be photographed, an electromagnet to be energized for a period of time controlled by the electric circuit, a shutter drive member to be initiated into forward movement by depression of a shutter button and returnable by a shutter cocking operation, the drive member being operable to energize the light measuring integration circuit when initiated into movement, a shutter opening and closing member reciprocally movable by the forward movement of the drive member to reciprocally slidingly move a pair of shutter blades in opposite directions to each other and to thereby open and close the shutter, an attraction member to be held attracted at its cocked position by the electromagnet while the electromagnet is energized and freed from the attracting force upon deenergization of the electromagnet, the attraction member being engageable with the drive member to stop its forward movement temporarily at a position where the shutter is fully opened when held attracted at the cocked position, the attraction member permitting the drive member to forwardly move past the stopped position when freed from the holding force at the cocked position, and delaying means for delaying the operation of the drive member during a period after the initiation of movement of the drive member until the shutter starts to open.

Claim 3

The electronic shutter as set forth in claim 1 wherein the delaying means comprises a space provided by the shutter cocking operation between a portion of the drive member and a portion of the opening and closing member where the first engagement of the drive member with the opening and closing member taken place, the space being sufficient to delay the operation of the drive member during a period after the initiation of movement of the drive member until tHe engagement takes place.

Claim 4

The electronic shutter as set forth in claim 1 wherein the delaying means comprises a governor engageable with the drive member to brake its forward movement and to thereby delay its operation during the period after the initiation of movement of the drive member until the shutter starts to open.

Claim 5

The electronic shutter as set forth in claim 1 wherein the delaying means comprises the combination of a space provided by the shutter cocking operation between a portion of the drive member and a portion of the opening and closing member where the first engagement of the drive member with the opening and closing member takes place and a governor engageable with the drive member to delay the operation of the drive member when the drive member is initiated into movement.

Claim 6

The electronic shutter as set forth in claim 1 wherein the attraction member has an attraction piece to be pressed against the attracting face of the electromagnet by the shutter cocking operation, a latch arm positioned in the path of forward movement of the drive member while the attraction piece is in intimate contact with the attracting face of the electromagnet to latch the drive member and stop its forward movement temporarily at the position where the shutter is fully opened and a driven arm to be pushed by the drive member to press the attraction piece against the attracting face of the electromagnet at its cocked position when the drive member is returned by the shutter cocking operation, the driven arm permitting the movement of the drive member further to its overcocked position and being elastically deformable to elastically absorb the pressing force acting between the attraction piece and the attracting face, the attraction member being urged for movement to follow the forward movement of the drive member while the electromagnet is unenergized.

Claim 7

The electronic shutter as set forth in claim 5 wherein the attraction member has a driven portion to be selectively pushed for making a bulb exposure to hold the attraction piece pressed against the attracting face of the electromagnet while being subjected to the pushing pressure.

Claim 8

The electronic shutter as set forth in claim 1 further comprising: an ammeter for detecting the variation of the resistivity of a photocell included in the light measuring integration circuit for detecting the brightness of the subject, and a pair of diaphragm blades for forming a diaphragm aperture the size of which is determined by the angle of deflection of the pointer of the ammeter.

Claim 9

The electronic shutter as set forth in claim 7 wherein the pair of the diaphragm blades is operated directly by the pointer to determine the diaphragm aperture size.

Claim 10

The electronic shutter as set forth in claim 7 wherein the diaphragm blades are operated by a diaphragm actuating member to determine the diaphragm aperture size, the diaphragm actuating member being movable by a variable amount upon depression of the shutter button to detect the position of the pointer.

Claim 11

The electronic shutter as set forth in claim 1 further comprising: another photcell having resistivity variable in accordance with the brightness of the subject of control a diaphragm aperture, another electromagnet to be supplied with an energizing current controlled by the photocell to give a variable magnetic force, a diaphragm actuating member movable by following the forward movement of the shutter drive member, a pair of diaphragm blades connected to the diaphragm actuating member and slidingly movable in directions opposite to each other to increase the size of the diaphragm aperture, and a rotary member for transmitting to the diaphragm actuating member a braking force in accordance with the magnitude of the magnetic force of the electromagnet to control the speed of increase in the diaphragm aperture size by the diaphragm blades.

Claim 12

The electronic shutter as set forth in claim 10 wherein the rotary member is a rotary dIsc made of an electroconductor having part of its periphery interposed between the magnetic poles of the electromagnet and the rotation of the rotary disc is braked by an eddy current produced between the disc and the electromagnet.

Claim 13

The electronic shutter as set forth in claim 10 wherein the rotary member is a rotary disc made of a magnetically sensitive material and toothed along its outer periphery to provide indentations and projections, the rotary disc being rotatably interposed between the magnetic poles of the electromagnet and the rotation of the rotary disc is braked by an electromagnetic attracting force acting on the projections.

Claim 14

The electronic shutter as set forth in claim 1 further comprising: a pair of diaphragm blades having diaphragm openings and light receiving openings, the pair of diaphragm blades being slidable in directions opposite to each other to increasingly overlap the respective openings to increase the sizes of the resulting apertures, a diaphragm actuating member to be initiated into movement by depression of the shutter button to bring the diaphragm blades into sliding movement, a diaphragm control electric circuit including a comparison circuit comprising a photocell having resistivity variable by detecting the brightness of the subject through the light receiving openings and a fixed resistor connected in series with the photocell, and an electromagnet to be energized with timing controlled by the diaphragm control electric circuit, the electromagnet being adapted to be energized by the resistivity of the photocell coming into balance with the resistivity of the fixed resistor to attract and stop the diaphragm blades sliding in opposite directions to each other and to thereby determine the size of the diaphragm aperture.

Claim 15

The electronic shutter as claimed in claim 13 wherein the diaphragm control electric circuit shares the photocell with the exposure time control electric circuit by way of two changeover switches having movable contact members operable by the diaphragm actuating member when the diaphragm aperture has been opened to its maximum size so as to disconnect the photocell from the diaphragm control electric circuit and to incorporate the same into the exposure time control electric circuit.

Claim 16

An electronic shutter comprising: An exposure time control electric circuit having a main switch to be closed by depression of a shutter button and including a light measuring integration circuit operable in accordance with the brightness of the subject to be photographed, an electromagnet to be energized for a period of time controlled by the electric circuit, a shutter drive member to be initiated into forward movement by depression of the shutter button and returnable by a shutter cocking operation, the drive member being operable to energize the light measuring integration circuit when initiated into movement, a shutter opening and closing member reciprocally movable by the forward movement of the drive member to reciprocally slidingly move a pair of shutter blades in opposite directions to each other and to thereby open and close the shutter, an attraction member to be held attracted at its cocked position by the electromagnet while the electromagnet is energized and freed from the attracting force upon deenergization of the electromagnet, the attraction member being engageable with the drive member to stop its forward movement temporarily at a position where the shutter is fully opened when held attracted at the cocked position, the attraction member permitting the drive member to forwardly move past the stopped position when freed from the holding force at the cocked position, a pair of diaphragm blades having diaphragm openings and light receiving openings, the pair of diaphragm blades being slidable in directions opposite to each other to increasingly overlap the respective openings to increase the sizes of the resulting apertures, a diaphragm actuating mEmber to be initiated into movement by depression of the shutter button before the initiation of movement of the drive member to bring the diaphragm blades into sliding movement, a diaphragm control electric circuit including a comparison circuit comprising a photocell having resistivity variable by detecting the brightness of the subject through the light receiving openings and a fixed resistor connected in series with the photocell, the diaphragm control electric circuit being operable before the energization of the exposure time control electric circuit, and an electromagnet to be energized with timing controlled by the diaphragm control electric circuit, the electromagnet being adapted to be energized by the resistivity of the photocell coming into balance with the resistivity of the fixed resistor to attract and stop the diaphragm blades sliding in opposite directions to each other and to thereby determine the size of the diaphragm aperture.

Claim 17

An electronic shutter comprising: An exposure time control electric circuit having a main switch to be closed by depression of a shutter button and including a light measuring integration circuit operable in accordance with the brightness of the subject to be photographed, an electromagnet to be energized for a period of time controlled by the electric circuit, a shutter drive member to be initiated into forward movement by depression of the shutter button and returnable by a shutter cocking operation, the drive member being operable to energize the light measuring integration circuit when initiated into movement, a shutter opening and closing member reciprocally movable by the forward movement of the drive member to reciprocally slidingly move a pair of shutter blades in opposite directions to each other and to thereby open and close the shutter, an attraction member to be held attracted at its cocked position by the electromagnet while the electromagnet is energized and freed from the attracting force upon deenergization of the electromagnet, the attraction member being engageable with the drive member to stop its forward movement temporarily at a position where the shutter is fully opened when held attracted at the cocked position, the attraction member permitting the drive member to forwardly move past the stopped position when freed from the holding force at the cocked position, a pair of diaphragm blades having diaphragm openings and light receiving openings, the pair of diaphragm blades being slidable in directions opposite to each other to increasingly overlap the respective openings to increase the sizes of the resulting apertures, a diaphragm actuating mEmber to be initiated into movement by depression of the shutter button before the initiation of movement of the drive member to bring the diaphragm blades into sliding movement, a diaphragm control electric circuit including a comparison circuit comprising a photocell having resistivity variable by detecting the brightness of the subject through the light receiving openings and a fixed resistor connected in series with the photocell, the diaphragm control electric circuit being operable before the energization of the exposure time control electric circuit, and an electromagnet to be energized with timing controlled by the diaphragm control electric circuit, the electromagnet being adapted to be energized by the resistivity of the photocell coming into balance with the resistivity of the fixed resistor to attract and stop the diaphragm blades sliding in opposite directions to each other and to thereby determine the size of the diaphragm aperture.

Claim 18

The electronic shutter as claimed in claim 15 wherein the diaphragm control electric circuit shares the photocell with the exposure time control electric circuit by way of two changeover switches having movable contact members operable by the diaphragm actuating member when the diaphragm aperture has been opened to its maximum size so as to disconnect the photocell from the diaphragm control electric circuit and to incorporate the same into the exposure time control electric circuit.