Exposure control system and method

Claim 2

An exposure control system comprising: exposure mechanism means selectively movable between a first position in blocking relation to an exposure opening and a second position defining a given aperture value in unblocking relation to the exposure opening, said exposure mechanism means defining a progressive variation of aperture values over the exposure opening when so moved between said first and said second positions; drive means energizable to effect movement of said exposure mechanism means between said first and said second position; exposure evaluating means having an output the value of which corresponds with an exposure evaluation of a scene; converter means responsive to said exposure evaluating means output and operative to derive a digital representation of the said value thereof; and control means including: counter means responsive to an input pulse train for sequentially counting the received pulses thereof and deriving a time dependent digital representation of the number of said pulses received, means when actuated for energizing said drive means to move said exposure mechanism means toward said second position to initiate an exposure interval during which scene light rays pass through the exposure opening and then in response to coincidence between said digital representations of said counter means and said converter means for energizing said drive means to move said exposure mechanism means to block said exposure opening and terminate said exposure interval, said energizing means including generator means for deriving said pulse train input to said counter at one frequency during energization of said exposure mechanism means effecting movement thereof from said first to said second position and at another frequency during location of said exposure mechanism means in said second position so as to vary the time dependent digital representation of said counter as a function of both said variation of aperture values and said given aperture value.

Claim 3

The exposure control system of claim 1 in which said generator means is operative to derive said pulse train input one frequency at a predetermined fixed value and said other frequency at one or more values lower than said one frequency.

Claim 4

The exposure control system of claim 1 in which said generator means is operative to derive said pulse train input one frequency at a predetermined fixed value and said other frequency at progressively diminishing values with respect to said one frequency value.

Claim 5

The exposure control system of claim 1 in which: said control means includes monitor means having a unique output condition responsive to said counter means achieving a digital representation corresponding with driving of said exposure mechanism means to said second position; and said generator means is responsive to said unique output condition for deriving said pulse train input other frequency.

Claim 6

The exposure control system of claim 4 in which: said drive means includes a pulse energized motor; and said energizing means is operative to pulse energize said drive means motor at a frequency representing a predetermined submultiple of said one frequency and to interrupt said energization iN the presence of said unique output condition.

Claim 7

The exposure control system of claim 5 in which said submultiple frequency is derived from said counter means so as to selectively energize said motor in slaved relationship with said counter means operation.

Claim 8

The exposure control system of claim 4 in which said monitor means is operative to derive said unique output condition subsequent to said coincidence of digital representations when said coincidence occurs as said exposure mechanism means attain said second terminal position.

Claim 9

An exposure control system comprising: exposure means having at least one light regulating element movable during initiation of an exposure interval to derive a dynamic definition of aperture values unblocking an exposure opening, to then statically define an aperture value at at least one open position, and finally movable to block said exposure opening to terminate said exposure interval; drive means energizably by a first sequence of drive pulses to move said exposure means to initiate said exposure interval and a further sequence of drive pulses to move said exposure means to terminate said exposure interval; exposure evaluating means having an output the value of which corresponds with an exposure evaluation of a scene; converter means responsive to said exposure evaluating means output and operative to derive a digital representation of the said value thereof; and control means including: counter means operative in response to an input pulse train to count the received pulses thereof and deriving a digital representation of the number of said pulses received, generator means for deriving said first sequence of drive pulses to initiate said interval of exposure and a related pulse train input to said counter means to provide synchronous operation between said counter means and said element movement during said initiation of said exposure interval, and responsive to coincidence between said counter means and said converter means digital representations for deriving said further sequence to move said exposure means to terminate said interval of exposure, said generating means deriving said pulse train input to said counter means at one frequency during element movement effecting said dynamic definition of aperture values and at another frequency during said static definition of aperture when said element attains said one open position so as to vary the digital representation of said counter as a function of both said dynamic and said static values of aperture.

Claim 10

An exposure control system comprising: exposure means having at least one light regulating element movable during initiation of an exposure interval to derive a dynamic definition of aperture values unblocking an exposure opening, to then statically define an aperture value at at least one open position, and finally movable to block said exposure opening to terminate said exposure interval; drive means energizably by a first sequence of drive pulses to move said exposure means to initiate said exposure interval and a further sequence of drive pulses to move said exposure means to terminate said exposure interval; exposure evaluating means having an output the value of which corresponds with an exposure evaluation of a scene; converter means responsive to said exposure evaluating means output and operative to derive a digital representation of the said value thereof; and control means including: counter means operative in response to an input pulse train to count the received pulses thereof and deriving a digital representation of the number of said pulses received, generator means for deriving said first sequence of drive pulses to initiate said interval of exposure and a related pulse train input to said counter means to provide synchronous operation between said counter means and said element movement during said initiation of said exposure interval, and responsive to coincidence between said counter means and said converter means digital representations for deriving said further sequence to move said exposure means to terminate said interval of exposure, said generating means deriving said pulse train input to said counter means at one frequency during element movement effecting said dynamic definition of aperture values and at another frequency during said static definition of aperture when said element attains said one open position so as to vary the digital representation of said counter as a function of both said dynamic and said static values of aperture.

Claim 11

The exposure control system of claim 8 in which said generator means includes multivibrator means operative to generate said one frequency at a predetermined fixed value and said other frequency at a progressively diminishing rate with respect to said one frequency.

Claim 12

The exposure control system of claim 8 in which: said control means includes monitor means having a unique output condition responsive to said counter means achieving a digital representation corresponding to pulsing of said exposure means element to said open position; and said generator means is responsive to said unique output condition for deriving said pulse train input other frequency.

Claim 13

The exposure control system of claim 8 in which said generator means includes astable multivibrator means having a pulse train output the frequency of which is responsive to the resistance of an R-C network, said network being configured such that said resistance is at a substantially fixed value during said dynamic aperture definition and varies in predetermined fashion during said static aperture value definition, so as to generate said other frequency at a progressively diminishing rate.

Claim 14

The exposure control system of claim 11 in which said R-C network resistance is at least in part developed by the channel impedance of field effect transistor means, and said generator means includes means for effecting the progressive increase of saiD channel impedance during said exposure means static aperture value definition.

Claim 15

The exposure control system of claim 12 in which: said control means includes monitor means having a unique output condition when said exposure means element reaches said terminal open position; and said generator means is responsive to said unique output condition for effecting said progressive increase of said channel impedance.

Claim 16

The exposure control system of claim 8 in which said control means includes monitor means having a unique output condition responsive to a said counter means achieving a digital representation corresponding with the pulsing of said exposure mechanism means element to said one open position, said generator means being operative in response to said unique output condition to suspend said pulse energization of said drive means until said coincidence of said digital representations.

Claim 17

An exposure control system comprising: exposure mechanism means having at least one light regulating element movable during initiation of an interval of exposure from a position blocking an exposure opening to a predetermined open position to derive a dynamic definition of aperture values unblocking said exposure opening during said movement and a static aperture value when said element attains said predetermined open position, and then movable into said blocking position to terminate said interval of exposure; exposure evaluating means having an output the value of which corresponds with an exposure evaluation of a scene; converter means responsive to said exposure evaluating means output and operative to derive a digital representation of the said value thereof; pulse energized motor means operative in the presence of select directional signals and an input pulse train energization to selectively move said exposure mechanism means element between said blocking position and said predetermined position; and control means including: counter means responsive to an input pulse train for sequentially counting the received pulses thereof and deriving a digital representation of the number of said pulses received, position monitor means having a unique output condition responsive to said counter means achieving a digital representation corresponding with sufficient pulsing of said motor to move said light regulating element to said predetermined open position, generator means for deriving said pulse train input to said counter means at one frequency during movement of said light regulating element to derive said dynamic definition of aperture values and responsive to said unique output condition of said monitor means to derive said pulse train to said counter means at another frequency when said light regulating element is at said predetermined open terminal position to vary the time of achievement of said counter digital representation as a function of both said dynamic and static aperture values, said generation means including means for pulse energizing said motor means at a select synchronous submultiple frequency of said one frequency and for deriving said select directional signals to effect movement of said light regulating element to said predetermined open position so as to initiate said exposure interval and in response to coincidence between said counter means and said converter means digital representation to effect movement of said light regulating element back to said blocking position.

Claim 18

An exposure control system comprising: exposure mechanism means having at least one light regulating element movable during initiation of an interval of exposure from a position blocking an exposure opening to a predetermined open position to derive a dynamic definition of aperture values unblocking said exposure opening during said movement and a static aperture value when said element attains said predetermined open position, and then movable into said blocking position to terminate said interval of exposure; exposure evaluating means having an output the value of which corresponds with an exposure evaluation of a scene; converter means responsive to said exposure evaluating means output and operative to derive a digital representation of the said value thereof; pulse energized motor means operative in the presence of select directional signals and an input pulse train energization to selectively move said exposure mechanism means element between said blocking position and said predetermined position; and control means including: counter means responsive to an input pulse train for sequentially counting the received pulses thereof and deriving a digital representation of the number of said pulses received, position monitor means having a unique output condition responsive to said counter means achieving a digital representation corresponding with sufficient pulsing of said motor to move said light regulating element to said predetermined open position, generator means for deriving said pulse train input to said counter means at one frequency during movement of said light regulating element to derive said dynamic definition of aperture values and responsive to said unique output condition of said monitor means to derive said pulse train to said counter means at another frequency when said light regulating element is at said predetermined open terminal position to vary the time of achievement of said counter digital representation as a function of both said dynamic and static aperture values, said generation means including means for pulse energizing said motor means at a select synchronous submultiple frequency of said one frequency and for deriving said select directional signals to effect movement of said light regulating element to said predetermined open position so as to initiate said exposure interval and in response to coincidence between said counter means and said converter means digital representation to effect movement of said light regulating element back to said blocking position.

Claim 19

The exposure control system of claim 15 in which said generator means is operative to derive said pulse train input one frequency at a predetermined fixed value and said other frequency at a predetermined value lower than said one frequency.

Claim 20

The exposure control system of claim 15 in which said generator means is operative to derive said pulse train input one frequency at a predetermined fixed value and said other frequency at a progressively diminishing value with respect to said one frequency value.

Claim 21

The exposure control system of claim 15 in which said terminal position monitor means is operative to derive said unique output condition subsequent to said coincidence of digital representations when said coincidence occurs substantially simultaneously with said exposure mechanism means element attaining said terminal open position.

Claim 22

The exposure control system of claim 15 in which said pulse energizing means select submultiple frequency is derived from said counter means so as to selectively energize said motor means in slaved relation with said counter means operation.

Claim 23

The exposure control system of claim 15 in which said generator means includes astable multivibrator means having a pulse train output the frequency of which is responsive to the resistance of an R-C network, said network being configured such that said resistance is at a substantially fixed value during said dynamic aperture definition and varies in predetermined fashion during said static aperture value definition, so as to generate said other frequency at a progressively diminishing rate.

Claim 24

The exposure control system of claim 20 in which said R-C network resistance is at least in part developed by the channel impedance of field effect transistor means, said generator means includes means for effecting the progressive increase of said channel impedance during said static aperture value definition.

Claim 27

The method of claim 22 wherein said determining step includes driving said counter at a fixed rate during initiation of said exposure interval and at a rate of decreasing frequency during said static position of said blade arrangement.