Color cathode-ray tube

Abstract

Abstract THE IMAGE AREA OF A COLOR CATHODE-RAY TUBE IS SCREENED BY A SLURRY PROCESS WHICH IS GENERALLY WELL KNOWN. THE SLURRY HAS, AS INGREDIENTS, A GADOLINIUM OXIDE PHOSPHOR, AN ORGANIC COLLOID OR GEL SUCH AS POLYVINYL ALCOHOL WHICH MAY BE SENSITIZED SO THAT ITS SOLUBILITY MAY BE INFLUENCED BY ACTINIC RADIATION, DEIONIZED WATER AS A SOLVENT AND A SENSITIZER HAVING A METAL CONSTITUENT AND SOLUBLE IN THE SOLVENT. CUSTOMARILY, AMMONIUM DICHROMATE IS USED AND, IN SOLUTION, PRODUCES DICHROMATE IONS WHICH MAY CHEMICALLY AND/OR PHYSICALLY REACT WITH THE POLYVINYL ALCOHOL AND THE PHOSPHOR. THE SLURRY PROCESS IS IMPROVED AND THE SCREENABILITY OF THE SLURRY AND THE BRIGHTNESS OF THE COLOR TUBE ENHANCED BY INCLUDING TWO ADDITIVES IN THE SLURRY. THE FIRST IS A POLYDENTATE CHELATING AGENT, SUCH AS ETHYLENEDIAMINETETRACETIC ACID, FOR REDUCING THE REACTION BETWEEN THE SENSITIZER, THE POLYVINYL ALCOHOL AND THE PHOSPHOR IN THE DARK, THAT IS TO SAY, IN THE ABSENCE OF ACTINIC RADIATION. THE SECOND IS A BASE SUCH AS AMMONIA OR AN AMINE, WHICH MAY HAVE COMPLEXING PROPERTIES, AND WHICH SHIFTS THE SLURRY TO AN ALKALINE PH MORE FAVORABLE TO COMPLEXING ACTION.

Inventors

• 👤 Carroll John Mellar
• 👤 Nicholas Zeliotis

Bibliographic Details