The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 20, 1981
Filed:
Nov. 05, 1979
Fuji Photo Film Co., Ltd., Minami-Ashigara, JP;
Abstract
A process of forming mask images having high contrast at the edges thereof and possessing high heat resistance and high durability comprising imagewise exposing a photographic light-sensitive material comprising a transparent support having thereon, in succession, a mask layer and a layer of an emulsion of a silver halide in a binder followed by development without employing fixing processing to form silver images at the image areas, removing the silver forming the silver images at the image areas with an aqueous solution containing ceric sulfate and sulfuric acid; then reducing the silver halide remaining at the non-image areas to silver; halogenating the silver formed in the non-image areas with an aqueous solution containing dichromate ions and halogen ions; heating the photographic material above about 200.degree. C. to thermally decompose the binder in the silver halide emulsion layer; removing selectively the thermally decomposed binder at the image areas with a solution capable of removing the thermally decomposed binder to uncover areas of the mask layer thereunder, and thereafter removing by etching the uncovered areas of the mask layer. The mask images formed can be used for making photo masks having high resolving power and high edge contrast as well as excellent durability.