Method of manufacturing electrical apparatus

Claim 1

IN THE PROCESS OF CONSTRUCTING A CATHODE RAY TUBE, THE STEPS OF: SCANNING WITH AN ELECTRON BEAM THOSE AREAS OF A COATING ON THE CONCAVE INTERIOR SURFACE OF AN EVACUATED ENVELOPE WHICH ARE SUSCEPTIBLE OF BEING IMPINGED BY SAID BEAM THROUGH A PERFORATED ELECTRODE LOCATED NEAR SAID SURFACE AND MAINTAINED AT A MORE NEGATIVE POTENTIAL THAN SAID SURFACE, SAID COATING BEING OPTICALLY DISTINGUISHABLE FROM SAID SURFACE AND HAVING SUBSTANTIALLY DIFFERENT SOLUBILITY BEFORE AND AFTER ELECTRON IMPINGEMENT, DISSOLVING THOSE PORTIONS OF SAID COATING HAVING THE GREATER OF SAID DIFFERENT SOLUBILITIES THEREBY TO DEVELOP A VISIBLE RECORD OF SAID BEAM IMPINGEMENT, PHOTOGRAPHING SAID RECORD THROUGH A LENS SYSTEM HAVING A NODAL POINT LOCATED IN SUBSTANTIALLY THE SAME POSITION RELATIVE TO SAID COATING AS THE EFFECTIVE ELECTRON CENTER OF SAID SCANNING BEAM, DEVELOPING SAID PHOTOGRAPH INTO A VISIBLE IMAGE OF SAID RECORD, PROJECTING SAID IMAGE ONTO A PHOTOSENSITIVE MATERIAL COATING THE INTERIOR SURFACE OF A CATHODE RAY TUBE FACEPLATE HAVING SUBSTANTIALLY THE SAME INTERIOR CONFIGURATION AS SAID SCANNED SURFACE THROUGH A LENS SYSTEM HAVING SUBSTANTIALLY THE SAME OPTICAL CHARACTERISTICS AS SAID PHOTOGRAPHING LENS SYSTEM AND HAVING ITS NODAL POINT LOCATED IN SUBSTANTIALLY THE SAME POSITION RELATIVE TO SAID FACEPLATE SURFACE IN WHICH SAID EFFECTIVE ELECTRON CENTER IS LOCATED RELATIVE TO SAID SCANNED SURFACE, SAID PHOTOSENSITIVE MATERIAL BEING SOLUBLE PRIOR TO ILLUMINATION AND BECOMING INSOLUBLE IN CONSEQUENCE TO ILLUMINATION, COATING ALL AREAS OF SAID PHOTOSENSITIVE MATERIAL WITH A PHOSPHOR, AND DISSOLVING PORTIONS OF SAID PHOTOSENSITIVE COATING WHICH HAVE REMAINED SOLUBLE AFTER SAID IMAGE PROJECTION, THEREBY REMOVING PHOSPHOR DEPOSITED ON SAID PORTIONS WHILE LEAVING IN PLACE PHOSPHOR DEPOSITED ON PORTIONS WHICH HAVE BECOME INSOLUBLE THROUGH ILLUMINATION.