Exposure control system for photographic apparatus

Claim 2

Apparatus for controlling an exposure control mechanism of a variety including a stepper motor unit having A first input for receiving a directional sense signal and a second input for receiving drive pulses to effect movement of said mechanism to provide control of the passage of light through an optical path, comprising: exposure control circuit means actuable to derive a time dependent output signal corresponding with an exposure evaluation; drive control means coupled to said second input and actuable to deliver a train of energizing pulses of drive frequency thereto; directional control means coupled with said first input for deriving predetermined first and second said directional sense signals; and means synchronizing the said actuations of said exposure control circuit means and said control means so as to effect a said exposure mechanism drive regulating an exposure in correspondence with said exposure evaluation.

Claim 3

The apparatus of claim 1 in which said drive control means is operative to drive said stepper motor at one pulse frequency in the presence of said first directional sense signal, to detect said exposure control circuit means output signal at a predetermined multiple of said one pulse frequency and respond to said signal detection to drive said stepper motor in the presence of said second directional sense signal.

Claim 4

The apparatus of claim 1 in which said drive control means includes: a pulse generator having an output frequency, f0; divider network means for deriving said drive frequency as a submultiple, f1, of said output frequency, f0; and coincidence means detecting said exposure control output signal at a time coinciding with the presence of a pulse at said output frequency, f0, and responsive to said detection for effecting the initiation of said stepper motor drive in the presence of said second directional sense signal.

Claim 5

The apparatus of claim 1 in which said synchronizing means includes bistable means initially actuable to commence an exposure control cycle of said apparatus and deriving a select stable output state in coincidence with said initial actuation and the presence of a pulse at said drive frequency for actuating said drive control means in synchronism with said pulse train drive frequency.

Claim 6

The apparatus of claim 1 in which said directional control means includes bistable means having a first stable output state providing said first directional sense signal and a second stable output state providing said second directional sense signal.

Claim 7

An exposure control system of a variety including an exposure mechanism movable from a first terminal position toward a second terminal position to define progressively varying apertural values over an optical path and subsequently movable into said first position to block said path, the improvement comprising: a stepper motor unit actuable in response to a directional signal and a train of energizing pulses for drivably moving said exposure mechanism between said positions; exposure evaluation means operative to derive an output signal corresponding with an exposure evaluation of a scene; directional control means for deriving said directional signal to cause said motor to rotate in a directional sense wherein said exposure mechanism is moved between said first and second positions to define an interval of exposure; drive control means for generating said energizing pulse train at frequency, f0; and phase control means responsive to said directional signal and to said energizing pulse train for actuating said motor to move said exposure mechanism, said phase control means being operative in the presence of a first said directional signal and an initial said energizing pulse train to actuate said motor to move said exposure mechanism toward said second terminal position, and being operative in response to a second said directional signal in the presence of said exposure evaluation means signal and to a subsequent said energizing pulse train to actuate said motor to move said eXposure mechanism toward said first terminal position.

Claim 8

An exposure control system of a variety including an exposure mechanism movable from a first terminal position toward a second terminal position to define progressively varying apertural values over an optical path and subsequently movable into said first position to block said path, the improvement comprising: a stepper motor unit actuable in response to a directional signal and a train of energizing pulses for drivably moving said exposure mechanism between said positions; exposure evaluation means operative to derive an output signal corresponding with an exposure evaluation of a scene; directional control means for deriving said directional signal to cause said motor to rotate in a directional sense wherein said exposure mechanism is moved between said first and second positions to define an interval of exposure; drive control means for generating said energizing pulse train at frequency, f0; and phase control means responsive to said directional signal and to said energizing pulse train for actuating said motor to move said exposure mechanism, said phase control means being operative in the presence of a first said directional signal and an initial said energizing pulse train to actuate said motor to move said exposure mechanism toward said second terminal position, and being operative in response to a second said directional signal in the presence of said exposure evaluation means signal and to a subsequent said energizing pulse train to actuate said motor to move said eXposure mechanism toward said first terminal position.

Claim 9

The exposure control system of claim 6 including: monitor means responsive to the introduction of a number of said energizing pulses to said monitor substantially corresponding with said exposure mechanism means movement between said terminal positions for deriving an output signal; and said phase control means is operative to interrupt said energizing pulse train introduction in the presence of said monitor means output signal.

Claim 10

The exposure control system of claim 6 in which said drive control means includes: a pulse generator having an output frequency, f0; coincidence means detecting said exposure control means output signal at a time coinciding with the presence of a sampling pulse at said output frequency, f0; and divider network means for deriving said subsequent energizing pulse train frequency, f1, as a submultiple of said output frequency, f0, in response to said coincidence means detection.

Claim 11

The exposure control system of claim 8 including delay means responsive to said divider network means derivation of said subsequent energizing pulse train for selectively delaying the presence of said subsequent energizing pulse train at said phase control means.

Claim 12

The exposure control system of claim 9 in which: said divider network means is configured including bistable multivibrator means responsive to coincidence means detection and to said pulse generator output and having an output stable, K2, at said frequency, f1; said delay means is configured including bistable multivibrator means having a stable output state, K3; said directional control means is configured including bistable multivibrator means having a stable output state, R, as said second directional signal; and said phase control means includes gate means having an output, Kz, satisfying the Boolean expression Kz RK2K3, for introducing said subsequent energizing pulse train to actuate said motor to move said exposure mechanism toward said first terminal position.

Claim 13

The exposure control system of claim 6 in which: said drive control means includes: a pulse generator having an output frequency, f0, and divider network means having an output, Ka, for deriving the initial said energizing pulse train frequency, f1, as a submultiple of said output frequency, f0; said directional control means is configured including bistable multivibrator means having an output condition, R'', as said first directional signal; and said phase control means includes gate means having an output condition, Kz, for introducing said initial energizing pulse train to actuate said motor to move said exposure mechanism toward said second terminal position in satisfaction of the Boolean expression: Kz R''Ka.

Claim 14

The exposure control system of claim 11 in which said phase control means includes: actuator means actuable to cause said system to commence an exposure cycle; exposure cycle identification means responsive to said actuator means actuation and having an output state, G3; and said gate means is configured to derive an output condition, Kx, satisfying the Boolean expression: Kz G3R''Ka.

Claim 15

The exposure control system of claim 12 wherein said directional control means and said exposure cycle identification means respective output conditions R'' and G3 are synchronous to said output, Ka.

Claim 16

In an exposure control apparatus of a variety including an exposure mechanism movable in a first direction to uncover an optical path and subsequently movable in a reverse direction to terminate an interval of exposure, the improvement comprising: stepper motor means responsive to an initial train oF energizing pulses in the presence of a first directional signal to drive said exposure mechanism to move in said first direction, and responsive to the presence of a second directional signal and a subsequent train of energizing pulses to reversibly drive said exposure mechanism in said reverse direction; exposure evaluation means operative to derive an evaluation signal corresponding with an exposure evaluation of a scene; and operational cycle logic means for selectively activating said exposure evaluation means, for deriving said first directional signal and generating said initial pulse train at a given frequency and, responsive to said evaluation signal within the interval of a pulse at said given frequency, to generate said subsequent energizing pulse train and to derive said second directional signal.

Claim 17

In an exposure control apparatus of a variety including an exposure mechanism movable in a first direction to uncover an optical path and subsequently movable in a reverse direction to terminate an interval of exposure, the improvement comprising: stepper motor means responsive to an initial train oF energizing pulses in the presence of a first directional signal to drive said exposure mechanism to move in said first direction, and responsive to the presence of a second directional signal and a subsequent train of energizing pulses to reversibly drive said exposure mechanism in said reverse direction; exposure evaluation means operative to derive an evaluation signal corresponding with an exposure evaluation of a scene; and operational cycle logic means for selectively activating said exposure evaluation means, for deriving said first directional signal and generating said initial pulse train at a given frequency and, responsive to said evaluation signal within the interval of a pulse at said given frequency, to generate said subsequent energizing pulse train and to derive said second directional signal.

Claim 18

The exposure control apparatus of claim 14 in which said operational cycle logic means is operative to respond to said exposure evaluation means signal at a time within said terminal pulse interval coinciding with a sampling frequency interval representing a select multiple of said given frequency.

Claim 19

The exposure control apparatus of claim 14 in which said operational cycle logic means includes: pulse generator means having a pulse output at frequency, f0; divider network means for deriving said energizing pulse train at said given frequency, f1, representing a select submultiple of said frequency, f0; and coincidence means responsive to said pulse output at frequency, f0, for detecting the presence of said exposure evaluation means signal in synchronism with a pulse at said frequency, f0.

Claim 20

The exposure control apparatus of claim 16 in which said divider network means is operative to generate said subsequent energizing pulse train in response to said coincidence means detection of said exposure evaluation signal.

Claim 21

A photographic exposure control system comprising: blade means; means for mounting said blade means for movement between a position wherein it will preclude the passage of scene light therethrough and at least one other position wherein it defines an opening through which scene light may pass; means for driving said blade means from one of its said positions into the other of its said positions responsive to a first directional signal input and an input of a train of energizing pulses and for driving said blade means from its said other position into its said one position responsive to a second directional signal input and an input of a train of said energy pulses; means for alternatively deriving said first and said second directional signals in a predetermined manner and feeding said signals as they are derived to said driving means; and means for developing a train of said energy pulses correlated to a time dependent exposure evaluation of a particular scene being photographed and simultaneously feeding said developed energy pulses to said driving means so that said drive means initiates the actuation of said blades prior to the completion of the development of said train of energy pulses.

Claim 22

A photographic exposure control system comprising: blade means; means for mounting said blade means for movement between a position wherein it will preclude the passage of scene light therethrough and at least one other position wherein it defines an opening through which scene light may pass; means for driving said blade means from one of its said positions into the other of its said positions responsive to a first directional signal input and an input of a train of energizing pulses and for driving said blade means from its said other position into its said one position responsive to a second directional signal input and an input of a train of said energy pulses; means for alternatively deriving said first and said second directional signals in a predetermined manner and feeding said signals as they are derived to said driving means; and means for developing a train of said energy pulses correlated to a time dependent exposure evaluation of a particular scene being photographed and simultaneously feeding said developed energy pulses to said driving means so that said drive means initiates the actuation of said blades prior to the completion of the development of said train of energy pulses.

Claim 23

The system of claim 18 wherein said driving means includes a stepper motor.

Claim 24

A photographic exposure control system for a camera, the camera having means for mounting photographic film material at a given focal plane, a lens for directing image-carrying rays from a scene along a given optical path to the camera focal plane, and selectively operable means for initiating an exposure cycle, said system comprising: a magnetically detented stepper motor having a output drive member, said motor being energizable by a select sequence of electrical pulses to rotate said output member in a step relation therewith; blade means; means for mounting said blade means for displacement between one terminal position wherein it will preclude passage of scene light along the given optical path and at least another position wheRein it defines an aperture value through which scene light may pass to the focal plane, said blade means being coupled to said output drive member and configured for movement therewith; means responsive to location of said blade means in said one terminal position for providing a given output signal; and means responsive to the exposure initiating means in the presence of said given output signal for generating a first predetermined sequence of electrical pulses to selectively energize said motor in a first directional sense to displace said blade means from said one terminal position to initiate an exposure interval during which scene light is directed to the focal plane and, in correlation with an evaluation of the scene being photographed, for subsequently generating a second predetermined sequence of electrical pulses to selectively energize said motor in an opposite directional sense to displace said blade means back to said one terminal position to again block the optical path thereby terminating the exposure interval.

Claim 25

A photographic exposure control system for a camera, the camera having means for mounting photographic film material at a given focal plane, a lens for directing image-carrying rays from a scene along a given optical path to the camera focal plane, and selectively operable means for initiating an exposure cycle, said system comprising: a magnetically detented stepper motor having a output drive member, said motor being energizable by a select sequence of electrical pulses to rotate said output member in a step relation therewith; blade means; means for mounting said blade means for displacement between one terminal position wherein it will preclude passage of scene light along the given optical path and at least another position wheRein it defines an aperture value through which scene light may pass to the focal plane, said blade means being coupled to said output drive member and configured for movement therewith; means responsive to location of said blade means in said one terminal position for providing a given output signal; and means responsive to the exposure initiating means in the presence of said given output signal for generating a first predetermined sequence of electrical pulses to selectively energize said motor in a first directional sense to displace said blade means from said one terminal position to initiate an exposure interval during which scene light is directed to the focal plane and, in correlation with an evaluation of the scene being photographed, for subsequently generating a second predetermined sequence of electrical pulses to selectively energize said motor in an opposite directional sense to displace said blade means back to said one terminal position to again block the optical path thereby terminating the exposure interval.

Claim 26

The system of claim 20 wherein said blade means is mounted for displacement between said one terminal position and a second terminal position wherein it defines a maximum aperture value, and said system additionally including means, responsive to energization of said motor to displace said blade means to said second terminal position, for terminating the energizing of said motor so as to minimize power consumption when said blade means reaches said second terminal position.

Claim 27

The system of claim 20 wherein said means responsive to the location of said blade means in said one terminal position includes switch means configured to be engaged by said blade means when said blade means is in its said one terminal position and providing a first output signal when said blade means is located in said one terminal position and a second output signal when said blade means is located in other than said one terminal position, said means for generating said first predetermined sequence of pulses is responsive to the exposure initiating means in the presence of said first output signal and for generating said second predetermined sequence is responsive to said scene evaluation in the presence of said second output signal.

Claim 28

An exposure control system of a variety including an exposure mechanism actuatable in response to an exposure initiation signal and an input pulse train to define changing aperture values unblocking an exposure path to initiate an exposure interval and then actuatable in response to an exposure termination signal to block the exposure path to terminate the exposure interval, and means deriving a time dependent evaluation signal corresponding with an exposure evaluation of a scene, said system comprising: means for generating one pulse train at a first frequency for actuating the exposure mechanism and for generating another pulse train at a second frequency which is a multiple of said given frequency; and means responsive to said evaluation signal for providing said termination signal, said means for providing said termination signal including means for detecting the presence of said exposure evaluation signal in synchronism with a pulse at said second frequency to provide a sampling rate which is a multiple of said first frequency.

Claim 29

An exposure control system of a variety including an exposure mechanism actuatable in response to an exposure initiation signal and an input pulse train to define changing aperture values unblocking an exposure path to initiate an exposure interval and then actuatable in response to an exposure termination signal to block the exposure path to terminate the exposure interval, and means deriving a time dependent evaluation signal corresponding with an exposure evaluation of a scene, said system comprising: means for generating one pulse train at a first frequency for actuating the exposure mechanism and for generating another pulse train at a second frequency which is a multiple of said given frequency; and means responsive to said evaluation signal for providing said termination signal, said means for providing said termination signal including means for detecting the presence of said exposure evaluation signal in synchronism with a pulse at said second frequency to provide a sampling rate which is a multiple of said first frequency.