Importance

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Abstract

The present invention relates to a method for making a viewing screen structure for a cathode-ray tube. The method includes the steps of coating a support surface with a film of a polymeric material, a suitable dichromate and a sensitizer therefor which is a chromium ion migration enhancer having a reduced sensitivity to thermal and dark hardening; exposing the film to an image in the form of radiant energy until the solubility of the irradiated regions thereof is selectively altered, thereby producing in the film regions of greater solubility and regions of lesser solubility; removing those regions of the film with greater solubility to bare portions of the underlying support surface while retaining those regions of the film with lesser solubility. The bare portions of the support surface and the retained film regions are overcoated with a composition of light-absorbing material which is adherent to the support surface. A solution of an oxidant is applied to the light absorbing material to selectively dissolve the retained film regions. The dissolved retained film regions and the light-absorbing material thereon are flushed-away leaving the light-absorbing material adhering to the support surface. Following the above-described steps, a luminescent screen is formed by depositing phosphor materials on areas of the support surface previously occupied by the retained film regions.

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First Claim