Image amplifier with magnification grid

Claim 1

AN ELECTRON-OPTICAL IMAGE AMPLIFIER COMPRISING AN ENVELOPE, A CONCAVE SPHERICAL PHOTOCATHODE FOR PRODUCING AN ELECTRON IMAGE CORRESPONDING TO AN OPTICAL IMAGE, A THIMBLE-SHAPED ANODE WITHIN SAID ENVELOPE SPACED FROM SAID PHOTOCATHODE, SAID THIMBLE-SHAPED ANODE HAVING AN APERTURE THEREIN FOR THE PASSAGE OF ELECTRONS EMANATING FROM THE PHOTOCATHODE RESULTING FROM LIGHT INCIDENT THEREON, A FLUORESCENT SCREEN POSITIONED TO RECEIVE ELECTRONS PASSING THROUGH THE APERTURE IN THE ANODE FOR CONVERTING THE ELECTRON IMAGE INTO A VISIBLE IMAGE, A CONDUCTIVE WALL SURROUNDING THE SPACE BETWEEN THE PHOTOCATHODE AND THE ANODE, MEANS TO APPLY POTENTIALS TO SAID PHOTOCATHODE, ANODE AND CONDUCTIVE WALL WHEREBY ELECTRONS PRODUCED BY THE PHOTOCATHODE ARE FOCUSSED AT THE FLUORESCENT SCREEN, AN ELECTROSTATIC SCREEN POSITIONED BETWEEN AND CLOSER TO THE ANODE THAN THE PHOTOCATHODE, SAID ELECTROSTATIC SCREEN HAVING AN APERTURE THEREIN THE CENTER OF WHICH LIES ON AN OPTICAL AXIS EXTENDING BETWEEN SAID PHOTOCATHODE AND SAID FLUORESCENT SCREEN, SAID ELECTROSTATIC SCREEN BEING COINCIDENT WITH AN EQUIPOTENTIAL PLANE DETERMINED BY THE POTENTIAL DISTRIBUTION BETWEEN THE PHOTOCATHODE AND THE ANODE, SAID SCREEN HAVING A SHAPE CORRESPONDING TO THAT OF SAID EQUIPOTENTIAL PLANE, AND MEANS TO APPLY A POTENTIAL TO SAID ELECTROSTATIC SCREEN EQUAL TO THE ANODE POTENTIAL WHEREBY A MAGNIFIED IMAGE IS PRODUCED ON THE FLUORESCENT SCREEN IN WHICH EACH PORTION CORRESPONDS TO A PORTION OF THE IMAGE ON THE PHOTOCATHODE.