Slurry process for coating particles upon the viewing-window surface of a cathode-ray tube

Claim 3

The method defined in claim 1 wherein said slurry is dispensed through a dispensing means and said heat is removed by cooling said slurry to temperatures lower than 22° C as it passes between said storage container and said dispensing means.

Claim 4

The method defined in claim 1 wherein said heat is removed by cooling said slurry in said storage container to temperatures lower than 22° C.

Claim 5

The method defined in claim 1 wherein, at said dispensing, said slurry temperature is about 20° to 21° C and said slurry viscosity is at about 35 to 45 centipoises.

Claim 6

In a method for coating the inner surfaces of a plurality of cathode-ray-tube viewing windows with particles of phosphor material comprising passing said viewing windows in a series and carrying out the following steps for each of said surfaces; A. rotating said inner surfaces facing upwardly about an axis that is substantially normal to and passes through the central portion of said surface, B. heating said surface to temperatures above 35° C, C. dispensing from a storage container onto said rotating surface a quantity of slurry comprised of said phosphor particles, a binder for said particles, a photosensitizer for said binder and a liquid vehicle, said quantity of slurry being in excess of that required for coating said surface, D. tilting said axis to cause said dispensed slurry to spread across said rotating surface, said slurry being heated by contact with said surface, E. collecting the excess slurry from said surface, F. returning said excess slurry to said storage container, G. and mixing said returned excess slurry with the slurry in said storage container, whereby the temperature of said mixed slurry rises above 22° C, the improvement comprising cooling said quantity of slurry to a temperature lower than 22° C.

Claim 7

In a method for coating the inner surfaces of a plurality of cathode-ray-tube viewing windows with particles of phosphor material comprising passing said viewing windows in a series and carrying out the following steps for each of said surfaces; A. rotating said inner surfaces facing upwardly about an axis that is substantially normal to and passes through the central portion of said surface, B. heating said surface to temperatures above 35° C, C. dispensing from a storage container onto said rotating surface a quantity of slurry comprised of said phosphor particles, a binder for said particles, a photosensitizer for said binder and a liquid vehicle, said quantity of slurry being in excess of that required for coating said surface, D. tilting said axis to cause said dispensed slurry to spread across said rotating surface, said slurry being heated by contact with said surface, E. collecting the excess slurry from said surface, F. returning said excess slurry to said storage container, G. and mixing said returned excess slurry with the slurry in said storage container, whereby the temperature of said mixed slurry rises above 22° C, the improvement comprising cooling said quantity of slurry to a temperature lower than 22° C.

Claim 8

The method defined in claim 5 wherein said cooled slurry has a viscosity of about 30 to 50 centipoises.

Claim 9

The method defined in claim 5 wherein a makeup slurry is also added to said storage container and mixed therein to produce a mixed slurry for use in coating subsequent viewing-window surfaces.

Claim 10

The method defined in claim 5 wherein the slurry is dispensed through a dispensing means and said cooling is achieved by passing said slurry through a cooling means between said storage container and said dispensing means.

Claim 11

The method defined in claim 5 wherein the central portion of said surface has a temperature of about 42° to 50° C, and the edge portions thereof are 3° to 5° cooler than said central portion.