Automatic focus positioning circuit

Claim 2

In an automatic focussing apparatus, the combination comprising: lens means for passing radiations from a scene therethrough to form a single image of said scene on a single predetermined plane; driving means; first coupling means coupling said driving means with said lens means, said driving means being operable to effect movement of said lens means between first and second positions, thereby affecting the definition of said single image on said single predetermined plane; light detection means responsive to the contrast definition of said single image for providing a data signal having a frequency characteristic which varies in accordance with said contrast definition of said single image; signal conditioning means responsive to said frequency characteristic of said data signal for providing a focus signal which varies in magnitude with said contrast definition of said single image; deflection means; a second coupling means, said second coupling means coupling said driving means and said deflection means, said deflection means being operable to effect a relative scanning movement of said single image with respect to said single predetermined plane; and signal responsive means connected to said driving means, said signal responsive means being responsive to said focus signal for terminating movement of said lens means at a position whereat said focus signal attained a maximum value during the movement of said lens means between said first and second positions.

Claim 3

The combination as set forth in Claim 1 wherein said deflection means further includes means for effecting said relative scanning movement at a constant rate.

Claim 4

In an automatic focusing apparatus, the combination comprising: lens means for passing radiations from a scene therethrough to form an image of said scene on a predetermined plane; driving means; first coupling means coupling said driving means with said lens means, said driving means being operable to effect movement of said lens means between first and second positions, thereby affecting the definition of said image on said predetermined plane; focus converter means responsive to the definition of said image on said image plane for generating a focus signal which varies in accordance therewith, said focus converter means including a deflection means and a second coupling means, said second coupling means coupling said driving means and said deflection means, said deflection means being operable to effect a relative scanning movement of said image with respect to said predetermined plane; and signal responsive means connecting said focus converter means and said driving means, said signal responsive means being responsive to said focus signal for terminating movement of said lens means at a position whereat said focus signal attained a maximum value during the movement of said lens means between said first and said second position, said signal responsive means including: first start switching member selectively operable for providing a start signal; signal generating means responsive to said start signal for providing first direction signal; terminal means arranged to be connected to a power supply for supplying a power signal; a power circuit connecting said terminal means to said driving means for applying said power signal to said driving means; first switching means serially connected in said power circuit, said first switching means being responsive to said first direction signal for providing a first effective contact closure in said power circuit thereby completing said power circuit and effecting a movement of said lens means from said first position toward said second position; memory means responsive to said focus signal for storing a signal representative of a focus position of said lens means during a movement of said lens means from said first toward said second position; first limit switching means operatively coupled to said lens means for providing a first limit signal when said lens means reaches said second position, said signal generating means being responsive to said first limit signal for generating a second direction signal; polarity reversing switching means connected in said power circuit, said polarity reversing switching means being responsive to said second direction signal for reversing the polarity of said power signal applied to said driving means, thereby effecting a movement of said lens means from said second position toward said first position; said memory means including means for generating a memory signal whenever said lens means reaches said focus position in moving from said second position toward said first position, said first switching means being responsive to said memory signal for opening said effective contact closure in power circuit means thereby terminating the operation of said driving means, said lens means being thereby positioned at said focus position.

Claim 5

In an automatic focusing apparatus, the combination comprising: lens means for passing radiations from a scene therethrough to form an image of said scene on a predetermined plane; driving means; first coupling means coupling said driving means with said lens means, said driving means being operable to effect movement of said lens means between first and second positions, thereby affecting the definition of said image on said predetermined plane; focus converter means responsive to the definition of said image on said image plane for generating a focus signal which varies in accordance therewith, said focus converter means including a deflection means and a second coupling means, said second coupling means coupling said driving means and said deflection means, said deflection means being operable to effect a relative scanning movement of said image with respect to said predetermined plane; and signal responsive means connecting said focus converter means and said driving means, said signal responsive means being responsive to said focus signal for terminating movement of said lens means at a position whereat said focus signal attained a maximum value during the movement of said lens means between said first and said second position, said signal responsive means including: first start switching member selectively operable for providing a start signal; signal generating means responsive to said start signal for providing first direction signal; terminal means arranged to be connected to a power supply for supplying a power signal; a power circuit connecting said terminal means to said driving means for applying said power signal to said driving means; first switching means serially connected in said power circuit, said first switching means being responsive to said first direction signal for providing a first effective contact closure in said power circuit thereby completing said power circuit and effecting a movement of said lens means from said first position toward said second position; memory means responsive to said focus signal for storing a signal representative of a focus position of said lens means during a movement of said lens means from said first toward said second position; first limit switching means operatively coupled to said lens means for providing a first limit signal when said lens means reaches said second position, said signal generating means being responsive to said first limit signal for generating a second direction signal; polarity reversing switching means connected in said power circuit, said polarity reversing switching means being responsive to said second direction signal for reversing the polarity of said power signal applied to said driving means, thereby effecting a movement of said lens means from said second position toward said first position; said memory means including means for generating a memory signal whenever said lens means reaches said focus position in moving from said second position toward said first position, said first switching means being responsive to said memory signal for opening said effective contact closure in power circuit means thereby terminating the operation of said driving means, said lens means being thereby positioned at said focus position.

Claim 6

The combination as set forth in claim 3 wherein said signal responsive means further includes lens return means selectively operable for returning said lens means to said first position following said positioning of said lens means at said focus position.

Claim 7

The combination as set forth in claim 4 wherein said lens return means includes: a second start switching member serially connected in said power circuit, said second start switching member being operatively coupled to said first start switching member for simultaneous operation therewith for providing a second effective contact closure in said power circuit, said first and second effective contact closures thereby completing said power circuit and effecting said movement of said lens means from said first toward said second position; second limit switching means providing a normally closed contact across said second start switching member, said second limit switching means being operatively coupled to said lens means for opening said normally closed contact when said lens means is in said first position, and means selectively operable for opening said second effective contact closure and re-establishing said first effective contact closure following said positioning of said lens means at said focus position whereby said second limit switching means and said second effective contact closure complete said power circuit thereby resuming the movement of said lens means toward said first position whereat said opening of said second limit switching means opens said power circuit and terminates said movement of said lens means.

Claim 8

The combination as set forth in claim 4 wherein said driving means includes a motor means, said first and second coupling means being coupled to said motor means, count signal generating means connected to said memory means, third coupling means operatively coupling said count sIgnal generating means with said motor means, said count signal generating means being operable for providing a count signal characterized by a series of pulses, the number of said pulses generated in any given time period being related to the distance moved by said lens means during said time period, said signal responsive means further including a peak detector and hold circuit responsive to said focus signal for providing a peak signal representative of the peak value by said focus signal during a movement of said lens means from said first to said second position, and a comparator circuit connecting said peak detector and hold circuit and said memory means, said comparator circuit being responsive to said peak signal and said focus signal for providing a reset signal whenever said focus signal and said peak signal are substantially equal, said memory means including counting means responsive to said first direction signal for up-counting and storing said pulses of said count signal, said counting means being further responsive to said reverse signal for down counting said pulses from the number of said stored pulses, said counting means being responsive to said reset signal for resetting said stored count to zero and holding said stored count at zero during the continuance of said reset signal, said memory signal being generated whenever said count stored by said counting means equals zero during a movement of said lens means from said second position to said first position.

Claim 9

The combination as set forth in claim 6 wherein said memory means further includes means for holding said count in said counting means at zero during a concurrence of said memory signal and said second direction signal.

Claim 10

The combination as set forth in claim 4 wherein said memory means includes: first peak detector and hold circuit; second peak detector and hold circuit; switching means normally connecting said focus connector means with said first peak detector and hold circuit, said switching means being responsive to said first direction signal for disconnecting said focus convertor means from said first peak detector and hold circuit and connecting said focus converter means to said second peak detector and hold circuit, said first and second peak detector and hold circuits being responsive to a receipt of said focus signal for generating first and second peak signals, respectively, representative of the peak value attained by said focus signal; and comparator means connected to said first and second peak detector and hold circuits said comparator means being responsive to a comparative equivalence of said first and second peak detector and hold circuits for generating said memory signal.