Exposure control circuitry

Claim 1

A device for measuring the density of a radiation image, comprising: an array of photosensitive detectors arranged relative to said image, each detector being responsive to the radiation derived from a respective area of said image and generating an output signal in accordance therewith; a source of potential; first circuit means comprising a number of discrete circuits connected in parallel across said source of poteNtial, each circuit including a resistor serially connected with one of said detectors; second circuit means including an amplifier circuit having one input terminal serially connected to each of said first circuit means for producing a control signal corresponding to each of said output signals; means serially connected with said amplifier circuit and one of said resistors and detectors of each discrete circuit and responsive to said control signal for limiting the current flow to only one detector and for inhibiting the flow of current from the other detectors in said array; and means connected between said one and another input terminal of said amplifier circuit for controlling said limiting means to render said detectors successively operative, whereby each of said control signals correspond to a respective image density factor.

Claim 2

A device for measuring the density of a radiation image, comprising: an array of photosensitive detectors arranged relative to said image, each detector being responsive to the radiation derived from a respective area of said image and generating an output signal in accordance therewith; a source of potential; first circuit means comprising a number of discrete circuits connected in parallel across said source of poteNtial, each circuit including a resistor serially connected with one of said detectors; second circuit means including an amplifier circuit having one input terminal serially connected to each of said first circuit means for producing a control signal corresponding to each of said output signals; means serially connected with said amplifier circuit and one of said resistors and detectors of each discrete circuit and responsive to said control signal for limiting the current flow to only one detector and for inhibiting the flow of current from the other detectors in said array; and means connected between said one and another input terminal of said amplifier circuit for controlling said limiting means to render said detectors successively operative, whereby each of said control signals correspond to a respective image density factor.

Claim 3

A device for measuring the density of a radiation image, comprising: an array of photosensitive detectors arranged relative to said image, each detector being responsive to the radiation derived from a respective area of said image and generating an output signal in accordance therewith; a source of potential; first circuit means comprising a number of discrete circuits connected in parallel across said source of poteNtial, each circuit including a resistor serially connected with one of said detectors; second circuit means including an amplifier circuit having one input terminal serially connected to each of said first circuit means for producing a control signal corresponding to each of said output signals; means serially connected with said amplifier circuit and one of said resistors and detectors of each discrete circuit and responsive to said control signal for limiting the current flow to only one detector and for inhibiting the flow of current from the other detectors in said array; and means connected between said one and another input terminal of said amplifier circuit for controlling said limiting means to render said detectors successively operative, whereby each of said control signals correspond to a respective image density factor.

Claim 4

A device for measuring the density of a radiation image, comprising: an array of photosensitive detectors arranged relative to said image, each detector being responsive to the radiation derived from a respective area of said image and generating an output signal in accordance therewith; a source of potential; first circuit means comprising a number of discrete circuits connected in parallel across said source of poteNtial, each circuit including a resistor serially connected with one of said detectors; second circuit means including an amplifier circuit having one input terminal serially connected to each of said first circuit means for producing a control signal corresponding to each of said output signals; means serially connected with said amplifier circuit and one of said resistors and detectors of each discrete circuit and responsive to said control signal for limiting the current flow to only one detector and for inhibiting the flow of current from the other detectors in said array; and means connected between said one and another input terminal of said amplifier circuit for controlling said limiting means to render said detectors successively operative, whereby each of said control signals correspond to a respective image density factor.