Non-settling process for coating a phosphor slurry on the inner surface of a cathode ray tube faceplate

A non-settling process for forming on an inner viewing surface of a color cathode ray tube faceplate a coating of an aqueous slurry composed of a photosensitized organic binder and a suspension of phosphor particles, which coating exhibits a high degree of coating weight uniformity, a relatively high phosphor coating weight, and suppressed radial streaking, said process comprising:

• supporting the faceplate such that the central axis of the faceplate has a substantial horizontal component;
• slowly rotating the faceplate about the central axis thereof while dispensing a stream of phosphor slurry onto the central region of the faceplate inner surface such that, due to gravitational forces and the slow rotation of the faceplate through the descending slurry stream, the slurry is suffused to the perimeter of the faceplate inner surface without any significant settling out of phosphor particles onto the faceplate;
• slowly rotating the faceplate for a predetermined delay interval effective to permit any tangential "sags" formed the dispensed coating during the dispensation and suffusion operation to even out;
• and
• levigating the coating by rotating the coated faceplate at a moderate angular velocity for a brief time interval, the joint effect of which moderate velocity and interval being to level and thin down the coating to a predetermined thickness while suppressing the formation of radial streaks in the coating radially outwardly of irregularities in or on the faceplate inner surface.

A non-settling process for forming on an inner viewing surface of a color cathode ray tube faceplate a coating of a super dense aqueous slurry composed of a photosensitized organic binder and a suspension of phosphor particles, which coating exhibits a high degree of coating weight uniformity and a relatively high phosphor coating weight, said process comprising:

• supporting the faceplate such that the central axis of the faceplate has a substantial horizontal component;
• slowly rotating the faceplate about the central axis thereof while dispensing onto the central region of the faceplate inner surface a stream of phosphor slurry having 36% to 45% (by weight) of phosphor material and a viscosity of 40 to 60 centipoise such that, due to gravitational forces and the slow rotation of the faceplate through the descending slurry stream, the slurry is suffused to the perimeter of the faceplate inner surface without any significant settling out of phosphor particles onto the faceplate;
• and
• levigating the coating by rotating the coated faceplate at a predetermined angular velocity for a predetermined time interval to level and thin down the coating to a predetermined thickness, the super density of the phosphor slurry increasing the phosphor coating weight in the resultant slurry coating.

A non-settling process for forming on an inner viewing surface of a color cathode ray tube faceplate a coating of an aqueous slurry composed of a photosensitized organic binder and a suspension of phosphor particles, which coating exhibits a high degree of coating weight uniformity and a relatively high phosphor coating weight, said process comprising:

• supporting the faceplate such that the central axis of the faceplate has a substantial horizontal component;
• slowly rotating the faceplate about the central axis thereof while dispensing a stream of phosphor slurry onto the central region of the faceplate inner surface such that, due to gravitational force and the slow rotation of the faceplate through the descending slurry stream, the slurry is suffused to the perimeter of the faceplate inner surface without any significant settling out of phosphor particles onto the faceplate;
• levigating the coating by rotating the coated faceplate at a predetermined angular velocity for a predetermined time interval to level and thin down the coating to a predetermined thickness;
• and
• collecting the excess slurry drained from the faceplate during the slurry dispensation operation and feeding it directly back for redispensation without the addition of a make-up slurry differing substantially from the dispensed slurry in phosphor content, viscosity, phosphor-to-binder ratio or particle size distribution.

A non-settling process for forming on an inner viewing surface of a color cathode ray tube faceplate a coating of a super dense aqueous slurry composed of a photosensitized organic binder and a suspension of phosphor particles, which coating exhibits a high degree of coating weight uniformity, a relatively high phosphor coating weight, and suppressed radial streaking, said process comprising:

• supporting the faceplate such that the central axis of the faceplate has a substantial horizontal component;
• slowly rotating the faceplate about the central axis thereof while dispensing onto the central region of the faceplate inner surface a stream of phosphor slurry having 36%-45% (by weight) of phosphor material and a viscosity of 40-60 centipoise such that, due to gravitational forces and the slow rotation of the faceplate through the descending slurry stream, the slurry is suffused to the perimeter of the faceplate inner surface without any significant settling out of phosphor particles onto the faceplate;
• slowly rotating the faceplate for a predetermined delay interval effective to permit any tangential "sags" formed in the dispensed coating during the dispensation and suffusion operation to even out;
• levigating the coating by rotating the coated faceplate at a moderate angular velocity for a brief time interval, the joint effect of which moderate velocity and interval being to level and thin down the coating to a predetermined thickness while suppressing the formation of radial streaks in the coating radially outwardly of irregularities in or on the faceplate inner surface;
• and
• collecting the excess slurry drained from the faceplate during the slurry dispensation operation and feeding it directly back for redispensation without the addition of a make-up slurry differing substantially from the dispensed slurry in phosphor content, viscosity, phosphor-to-binder ratio or particle size distribution.