Cathode-ray display system having electrostatic magnifying lens

Claim 1

A CATHODE-RAY TUBE HAVING AN ELECTRON GUN FOR DIRECTING A CATHODE-RAY BEAM ALONG A PREDETERMINED PATH FROM AN ELECTRON SOURCE TO A VIEWING SCREEN, SAID TUBE BEING ADAPTED FOR USE WITH DEFLECTION MEANS FOR ESTABLISHING DEFLECTING FIELDS WITHIN THE TUBE HAVING AN EFFECTIVE DEFLECTION CENTER LOCATED BETWEEN THE ELECTRON SOURCE AND THE VIEWING SCREEN FOR DEFLECTING THE BEAM TO SCAN THE SAME ACROSS THE SCREEN, SAID TUBE HAVING A RADIALLY SYMMETRICAL LENS STRUCTURE PROVIDING A RADIALLY SYMMETRICAL DIVERGENT ELECTRON LENS LOCATED BETWEEN THE POSITION OF THE DEFLECTION CENTER AND THE VIEWING SCREEN AND EFFECTIVE TO MAGNIFY THE SCAN OF THE BEAM, SAID LENS STRUCTURE INCLUDING A SUBSTANTIALLY FLAT FINELY APERTURED MESH-LIKE CONDUCTING ELECTRODE LOCATED IN THE PATH OF THE BEAM AND BEING AT LEAST PARTIALLY TRANSPARENT TO THE ELECTRONS OF THE BEAM, FIRST AND SECOND TUBULAR CONDUCTING ELECTRODES POSITIONED ON OPPOSITE SIDES OF SAID FLAT CONDUCTING ELECTRODE AND BETWEEN THE DEFLECTION CENTER AND THE VIEWING SCREEN, MEANS APPLYING POTENTIALS TO SAID ELECTRODES WITH THE POTENTIALS APPLIED TO SAID TUBULAR ELECTRODES BEING SUBSTANTIALLY GREATER THAN THE POTENTIAL APPLIED TO SAID FLAT ELECTRODE SO THAT EACH TUBULAR ELECTRODE COOPERATES WITH SAID FLAT ELECTRODE TO PROVIDE AN EFFECTIVE DIVERGENT LENS SECTION, AND MEANS ESTABLISHING FOCUSING FIELDS WITHIN THE TUBE EFFECTIVE TO COMPENSATE FOR THE DIVERGENT EFFECT OF SAID ELECTRON LENS ON THE BEAM AND THEREBY FOCUSING THE BEAM ON THE VIEWING SCREEN.