Claims
- 1. For use in the manufacture of a color cathode ray tube having a shadow mask with a pattern of minute apertures, a method for preventing particle occlusion of the apertures during manufacture comprising applying a removable film to at least one side of said mask prior to the mask-related CRT manufacturing operation which would expose the mask to dust particles, and subsequently removing said film, said film having a small, substantially uniform thickness dimensions, a low index of refraction, and high transparency so as to exhibit a negligible optical effect during photoscreening operations.
- 2. For use in the manufacture of a color cathode ray tube having a shadow mask and a faceplate with a target area for receiving in a photoscreening process at least one pattern of phosphor deposits, said shadow mask having a pattern of minute beam-passing apertures used during the photoscreening process, but ultimately for color selection during tube operation, a method for preventing particle occlusion of the apertures during manufacture comprising:
- prior to the mask-related CRT manufacturing operation which would expose the mask to dust particles, depositing on a least one side of said mask a removable film characterized by having physically-related properties including pyrolyzability, non-flammability, static charge dispersibility, and dust rejection, said film being further characterized by having optically related properties including an extremely small, substantial uniform thickness dimension in the range of 4 to 6 micro-inches, a low index of refraction, and a high transparency, said optically related properties causing the film to exhibit a negligible optical effect during photoscreening operations;
- and, subsequently removing said film.
- 3. For use in the manufacture of a color cathode ray tube having a shadow mask and a faceplate with a target area for receiving in a photoscreening process at least one pattern of phosphor deposits, said shadow mask having a pattern of minute beam-passing apertures used during the photoscreening process, but ultimately for color selection during tube operation, a method for preventing particle occlusion of the apertures during manufacture comprising:
- disposing on at least one side of said mask a removable film effective to prevent particle occlusion of said apertures, said film being characterized by having properties including an extremely small, substantially uniform thickness dimension, a low index of refraction, and a high transparency;
- photoscreening said phosphor deposits on said faceplate, including exposing said screen to actinic light through said apertures and said film; and
- removing said film.
- 4. For use in the manufacture of a color cathode ray tube having a shadow mask and a faceplate with a target area for receiving in a photoscreening process at least one pattern of phosphor deposits, said shadow mask having a pattern of minute beam-passing apertures used during the photoscreening process, but ultimately for color selection during tube operation, a method for preventing particle occlusion of the apertures during manufacture comprising:
- disposing on a least one side of said mask a film removable by pyrolyzation, and effective to prevent particle occlusion of said apertures, said film being characterized by having properties including an extremely small, substantially uniform thickness dimension, a low index of refraction, and a high transparency;
- photoscreening said phosphor deposits on said faceplate, including exposing said screen to actinic light through said apertures and said film; and
- removing said film by pyrolyzing it.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a division of application Ser. No. 768,522 filed Aug. 22, 1985.
US Referenced Citations (8)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2238546 |
Feb 1973 |
DEX |
Non-Patent Literature Citations (2)
Entry |
Ahn et al, IBM Tech. Disc. Bull., vol. 14, No. 11, Apr. 1972, p. 3426. |
Hershel, SPIE, vol. 275, Semiconductor Microlithography VI, 1981, pp. 23-28. |
Divisions (1)
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Number |
Date |
Country |
Parent |
768522 |
Aug 1985 |
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