Cathode ray tubes employing a novel convergent electrostatic lens system for beam modulation

Claim 1

AN ELECTRON BEAM CONTROL SYSTEM FOR A CATHODE RAY TUBE, CHARACTERIZED BY COMPRISING A CONDUCTIVE PLANAR MEMBER CONTAINING ONLY ONE APERTURE OF ANY SUITABLE CONFIGURATION SO THAT UPON INCIDENCE OF AN ELECTRON BEAM ON ONE SIDE OF THE PLANAR MEMBER A MODULATED ELECTRON BEAM INTERCEPTED PARTLY THEREOF BY SAID APERTURE CONFIGURATION PASSES THERETHROUGH TOM EMERGE FROM THE OPPOSITE SIDE OF SAID MEMBER, TARGET DEFLECTION MEANS FOR DEFLECTING THE ELECTRON BEAM WHICH HAS PASSED THROUGH SAID MEMBER IN MOVING TOWARDS A TARGET MEANS, AN ELECTRON GUN ELEMENT FOR PRODUCING AN ELECTRON BEAM HAVING A FIXED CROSS-SECTIONAL AREA, MEANS CONTROLLED BY AN EXTERNALLY APPLIED VOLTAGE FOR CAUSING SAID ELECTRON BEAM TO BE DEFLECTED AND TO BE INCIDENT ON ONE SIDE OF SAID PLANAR MEMBER ADJACENT TO SAID APERTURE, AND AN ELECTROSTATIC ELECTRON LENS COMPRISING SAID PLANAR MEMBER AND ELECTRODES DISPOSED ON OPPOSITE SIDES OF SAID PLANAR MEMBER FOR CAUSING AN ELECTRON BEAM WHICH HAS DEVIATED FROM THE DEFLECTION CENTER OF SAID DEFLECTION CAUSING MEANS TO CONVERGE AT A POINT ALONG THE CENTRAL AXIS OF THE CATHODE RAY TUBE; SAID ELECTRODES BEING TWO CYLINDRICAL ELECTRODES HAVING THEIR LONGITUDINAL AXES DISPOSED ON THE CENTRAL AXIS OF THE CATHODE RAY TUBE CONFRONTING EACH OTHER WITH THE PLANAR MEMBER INTERPOSED THEREBETWEEN AND BEING MAINTAINED AT A POTENTIAL HIGHER THAN THE POTENTIAL OF SAID ELECTRODES; SAID ELECTRON LENS BEING A PURELY CONVERGENT ELECTROSTATIC LENS FORMING A CONVERGENT REGION AROUND SAID PLANAR MEMBER BY PERFECTLY ELIMINATING DIVERGENT OR NON-CONVERGENT PARTS, FROM THE REGION OF ACTION OF SAID ELECTRON LENS; WHEREBY THE BRIGHTNESS OF SAID TARGET MEANS IS CONTROLLED IN RESPONSE TO THE EXTERNAL VOLTAGE APPLIED TO SAID DEFLECTION CAUSING MEANS.