Image storage tube

Claim 1

A CAMERA TUBE SYSTEM COMPRISING: AN EVACUATED ENVELOPE HAVING OPPOSITE ENDS; A PHOTOCATHODE AT ONE END OF SAID ENVELOPE; A PERFORATE STORAGE SCREEN EXTENDING TRANSVERSELY ACROSS SAID ENVELOPE INTERMEDIATE SAID ENDS, SAID SCREEN COMPRISING A FINE MESH METAL SCREEN AND A SCREEN FORMED OF SECONDARY-EMISSIVE DIELECTRIC MATERIAL HAVING ONE SIDE THEREOF FACING SAID PHOTOCATHODE; A FIRST SOURCE OF POTENTIAL COUPLED TO SAID PHOTOCATHODE AND A SECOND SOURCE OF POTENTIAL COUPLED TO SAID METAL SCREEN, SAID FIRST AND SECOND POTENTIAL SOURCES BEING PROPORTIONED SO THAT SAID PHOTOCATHODE EMITS AN ELECTRON IMAGE TOWARD SAID STORAGE SCREEN RESPONSIVE TO IMPINGEMENT OF AN OPTICAL IMAGE ON SAID PHOTOCATHODE WHEREBY A CHARGE IMAGE IS DEVELOPED ON SAID PHOTOCATHODE WHEREBY A CHARGE IMAGE SAID ELECTRON IMAGE; AN ELECTRON GUN AT THE OTHER END OF SAID ENVELOPE AND INCLUDING A CATHODE; A THIRD SOURCE OF POTENTIAL COUPLED TO SAID CATHODE AND PROPORTIONED SO THAT SAID ELECTRON GUN DIRECTS A BEAM OF ELECTRONS TOWARD THE SIDE OF SAID METAL SCREEN REMOTE FROM SAID DIELECTRIC MATERIAL WHEREBY A PART OF THE ELECTRONS OF SAID BEAM PASS THROUGH SAID STORAGE SCREEN AND ANOTHER PART OF THE ELECTRONS OF SAID BEAM ARE REFLECTED BACK TOWARD SAID ELECTRON GUN RESPONSIVE TO THE RESPECTIVE ELEMENTAL CHARGES ON SAID DIELECTRIC MATERIAL; A SECONDARY EMISSION MULTIPLIER AT THE OTHER END OF SAID TUBE AND A FOURTH SOURCE OF POTENTIAL COUPLED THERETO AND PROPORTIONED TO ATTRACT SAID REFLECTED PART OF SAID BEAM ELECTRONS; A SECONDARY-EMISSION COLLECTOR ELECTRODE POSITIONED BETWEEN SAID PHOTOCATHODE AND STORAGE SCREEN, AND A FIFTH SOURCE OF POTENTIAL COUPLED TO SAID COLLECTOR ELECTRODE AND PROPORTIONED SO THAT SAID COLLECTOR ELECTRODE ATTRACTS SECONDARY ELECTRONS EMITTED FROM SAID DIELECTRIC MATERIAL RESPONSIVE TO IMPINGEMENT OF SAID ELECTRON IMAGE THEREON; AN OUTPUT CIRCUIT COUPLED TO SAID MULTIPLIER FOR PROVIDING AN OUTPUT SIGNAL RESPONSIVE TO THE CURRENT FLOW IN SAID MULTIPLIER; MEANS FOR REPETITIVELY SCANNING SAID ELECTRON BEAM ACROSS SAID METAL SCREEN WHEREBY THE FLOW OF SAID ONE ELECTRON BEAM PART IS MODULATED IN RESPONSE TO SAID CHARGE IMAGE THEREBY DEVELOPING A TIME-BASED SIGNAL IN SAID OUTPUT CIRCUIT RESPONSIVE TO SAID CHARGE IMAGE, INPUT RADIATION MEANS APPLYING A FLOOD BEAM IN PLACE OF SAID OPTICAL IMAGE TO SAID PHOTOCATHODE, SAID FIRST SOURCE OF POTENTIAL BEING SUBSTANTIALLY NEGATIVE WITH RESPECT TO SAID SECOND SOURCE, AND A SIXTH SOURCE OF POTENTIAL WHICH IS LESS NEGATIVE THAN SAID FIRST SOURCE WITH RESPECT TO SAID SECOND SOURCE AND SUBSTANTIALLY POSITIVE WITH RESPECT TO SAID FIRST SORUCE, AND SWITCHING MEANS HAVING FIRST AND SECOND ALTERNATE POSITIONS FOR SELECTIVELY COUPLING SAID PHOTOCATHODE TO SAID FIRST SOURCE TO PERMIT SAID CHARGE IMAGE TO FORM ON SAID DIELECTRIC MATERIAL AND TO SAID SIXTH SOURCE TO PERMIT ELECTRONS PRODUCED BY SAID FLOOD BEAM ON SAID PHOTOCATHODE TO ERASE SAID CHARGE IMAGE FROM SAID DIELECTRIC MATERIAL.