Processing of cathode-ray tubes

Claim 2

In the processing of a cathode-ray tube, having a phosphor screen and a gun assembly enclosed within an evacuated envelope, which processing includes the steps of: (1) applying phosphor, a filming layer and a superposed conductive backing layer to said screen of said tube; (2) heating said tube to a temperature exceeding the vaporization temperature of water for a predetermined period of time to effect bakeout of said screen; (3) sealing said gun assembly in position within said envelope; and (4) evacuating said envelope, the improvement which comprises injecting a predetermined amount of water into said envelope subsequent to said step of applying phosphor but prior to said evacuating step.

Claim 3

The process improvement in accordance with claim 1 in which the water is injected while said envelope is at a temperature above the vaporization temperature of water to convert the injected water into water vapor or immediately prior to the heating of said envelope to such a temperature.

Claim 4

The process improvement in accordance with claim 2 in which the water is injected after said heating step and prior to said evacuating step.

Claim 5

The process improvement in accordance with claim 3 in which water is injected into said envelope prior to said gun assembly sealing step.

Claim 6

The process in accordance with claim 4, for processing a tube having a faceplate section including said screen and another section for accommodating said gun assembly and to be sealed to said faceplate section to form said envelope, in which water is injected at the completion of the step of sealing said envelope sections together and as the envelope is transported to the work station for gun assembly sealing.

Claim 7

The improvement in accordance with claim 5, for processing a tube having a reduced neck section into which said gun assembly is to be inserted, in which water is injected into said envelope by soaking a sponge in water and thereafter inserting said sponge into said neck section.

Claim 8

The process improvement in accordance with claim 6 in which said sponge is dimensioned to be self-retaining within said neck and has sufficient porosity to admit ambient air into said envelope as said envelope is transported to said work station for gun assembly sealing.

Claim 9

The process improvement in accordance with claim 7 in which said envelope is transported to said work station with its neck facing downwardly and with said sponge in position within said neck.

Claim 10

The process improvement in accordance with claim 1 in which the amount of water injected into said envelope establishes a controlled atmosphere therein having a water vapor content of at least about 900 parts per million by volume.

Claim 11

The process improvement in accordance with claim 1 in which the amount of water injected into said envelope establishes a controlled atmosphere therein having a dew point within the range of minus 4* and plus 10* F.

Claim 12

In the proceSsing of a cathode-ray tube, having a phosphor screen and a gun assembly enclosed within an evacuated envelope comprising a faceplate section sealed to a conically shaped body section, which processing includes the steps of: (1) applying phosphor, a filming layer and a superposed conductive backing layer to said faceplate section to constitute the screen of said tube; (2) heating said tube to a temperature exceeding the vaporization temperature of water for a predetermined period of time to effect bakeout of said screen; (3) applying a sealing frit between meeting surfaces of said faceplate and body sections and further heating said envelope at a temperature exceeding the vaporization temperature of water to unite said envelope sections to one another; (4) sealing said gun assembly in position within said envelope; and (5) evacuating said envelope, the improvement which comprises injecting water into said envelope after said frit sealing step but prior to said gun assembly step and while said envelope is at a temperature above the vaporization temperature of water to convert the injected water into water vapor.

Claim 13

In the proceSsing of a cathode-ray tube, having a phosphor screen and a gun assembly enclosed within an evacuated envelope comprising a faceplate section sealed to a conically shaped body section, which processing includes the steps of: (1) applying phosphor, a filming layer and a superposed conductive backing layer to said faceplate section to constitute the screen of said tube; (2) heating said tube to a temperature exceeding the vaporization temperature of water for a predetermined period of time to effect bakeout of said screen; (3) applying a sealing frit between meeting surfaces of said faceplate and body sections and further heating said envelope at a temperature exceeding the vaporization temperature of water to unite said envelope sections to one another; (4) sealing said gun assembly in position within said envelope; and (5) evacuating said envelope, the improvement which comprises injecting water into said envelope after said frit sealing step but prior to said gun assembly step and while said envelope is at a temperature above the vaporization temperature of water to convert the injected water into water vapor.

Claim 14

The improvement, in accordance with claim 11, for processing a cathode-ray tube in which said body section of said envelope terminates in a reduced-diameter neck for accepting said gun assembly, in which said body section has an internal coating of conductive material extending partially into said neck and in which said water is injected by soaking a sponge in water and inserting said sponge into said neck to a depth that leaves a portion of said neck separating the leading edge of said sponge and the adjacent edge of said conductive coating.

Claim 15

The process improvement in accordance with claim 9 in which the amount of water injected establishes a controlled atmosphere having a water vapor content within the range 900 to 2,000 parts per million by volume.