Method of producing a film of uniform electroconductivity on refractory bases

Claim 1

IN THE METHOD OF PROVIDING A REFRACTORY BASE HAVING LEADING AND TRAILING EDGES AND SIDE EDGES WITH A TRANSPARENT ELECTROCONDUCTIVE METAL OXIDE FILM WHEREIN THE TOTAL RESISTANCE OF THE FILM ALONG CURRENT PATHS BETWEEN THE SPACED SIDE EDGES AND IN THE AREAS ADJACENT THE LEADING AND TRAILING EDGES IS SUBSTANTIALLY EQUAL TO THAT ALONG CURRENT PATHS BETWEEN SAID SPACED EDGES IN THE REMAINING PORTIONS OF THE FILM WHICH COMPRISES HEATING SAID BASE TO A TEMPERATURE ABOVE 400* F. BUT BELOW THE TEMPERATURE AT WHICH THE BASE BECOMES MOLTEN, ESTABLISHING A SPRAY OF THE FILM FORMING COMPOUND, PASSING THE HEATED BASE AT A UNIFORM SPEED IN A SINGLE DIRECTION THROUGH THE SPRAY, ROTATING THE SPRAY IN A SINGLE DIRECTION SUBSTANTIALLY PARALLEL WITH THE DIRECTION OF THE BASE DURING ONLY THE TIME THE LEADING AND TRAILING EDGES OF THE BASE ARE IN CONTACT WITH THE SPRAY TO EFFECT THE DEPOSITION OF A FILM OF A DIFFERENT SURFACE RESISTIVITY THAN IS DEPOSITED WHEN THE SPRAY IS NOT BEING ROTATED AND MAINTAINING RELATIVE MOVEMENT BETWEEN THE BASE AND THE SPRAY AT A RATE GREATER THAN WILL PERMIT DEPOSITION OF A MAXIMUM THICKNESS OF FILM, THE FILM SO FORMED HAVING A CURRENT FLOW SUBSTANTIALLY THE SAME BETWEEN ANY PAIR OF OPPOSING POINTS IN THE SPACED EDGES THROUGHOUT THEIR LENGTH UPON THE APPLICATION OF AN ELECTRIC CURRENT THEREACROSS.