Apparatus for producing visual images of x-rayed objects

Claim 1

APPARATUS FOR PROVIDING A VISUAL IMAGE OF AN XRAYED OBJECT COMPRISING AN X-RAY GENERATOR ADAPTED TO EMIT A BEAM OF X-RAYS THROUGH SAID OBJECT; A HIGH VOLTAGE SOURCE COUPLED TO SAID X-RAYS GENERATOR, THE QUANTUM ENERGY OF SAID EMITTED X-RAYS BEING RELATED TO THE VALUE OF SAID HIGH VOLTAGE; AN IMAGE INTENSIFIER ELEMENT DISPOSED IN A MANNER TO RECEIVE SAID X-RAY BEAM AFTER IT HAS PASSED THROUGH SAID OBJECT, SAID IMAGE INTENSIFIER HAVING AN INPUT PHOSPHOR AND AN OUTPUT PHOSPHOR, SAID INPUT PHOSPHOR BEING ADAPTED TO EMIT LIGHT IN RESPONSE TO IMPINGENT X-RAYS; A PHOTOELECTRIC CATHODE INCLUDE WITHIN SAID IMAGE INTENSIFIER ELEMENT AND DISPOSED IN JUXTAPOSITION TO SAID INPUT PHOSPHOR, SAID PHOTOELECTRIC CATHODE BEING ADAPTED TO EMIT ELECTRONS IN RESPONSE TO LIGHT IMPINGENT UPON IT FROM SAID INPUT PHOSPHOR; MEANS ADAPTED TO ACCELERATE SAID ELECTRONS EMITTED FROM SAID PHOTO CATHODE TO SAID OUTPUT PHOSPHOR FOR PRODUCING A VISUAL IMAGE THEREON AT INCREASED BRIGHTNESS RELATIVE TO THE BRIGHTNESS OF SAID INPUT PHOSPHOR; SIGNAL GENERATING MEANS COUPLED TO SAID PHOTO CATHODE AND ADPATED TO PROVIDE AS AN OUTPUT A VOLTAGE SIGNAL HAVING AN AMPLITUDE VARYING IN ACCORDANCE WITH VARIATIONS IN THE NUMBER OF ELECTRONS EMITTED FROM SAID PHOTO CATHODE; AMPLIFYING MEANS COUPLED TO THE OUTPUT OF SAID SIGNAL GENERATOR AND ADAPTED TO PROVIDE AS AN OUTPUT SAID SIGNAL GENERATOR OUTPUT SIGNAL AMPLIFIED BY A PRESELECTED FACTOR; A BALANCING AMPLIFIER HAVING FIRST AND SECOND INPUT TERMINALS AND ADAPTED TO PROVIDE AN OUTPUT IN RESPONSE TO ANY DIFFERENCE IN VOLTAGE BETWEEN SAID FIRST AND SECOND INPUT TERMINALS; A SOURCE OF REFERENCE VOLTAGE COUPLED TO SAID FIRST INPUT TERMINAL, SAID SECOND INPUT TERMINAL BEING COUPLED TO THE OUTPUT OF SAID AMPLIFIER MEANS; MEANS REPONSIVE TO THE OUTPUT OF SAID BALANCING AMPLIFIER FOR VARYING THE VALUE OF SAID HIGH VOLTAGE IN A MANNER TENDING TO DECREASE ANY VOLTAGE IMBALANCE BETWEEN SAID FIRST AND SECOND INPUT TERMINALS ON SAID BALANCING AMPLIFIER.