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:
Mar. 10, 1998
Filed:
Jul. 02, 1996
Hiroyuki Nakamura, Tokyo, JP;
Naoya Hayashi, Tokyo, JP;
Abstract
A gradation mask having spatially stepped transmittance in at least three steps including substantially 0% and substantially 100%, the transmittance being regulated stepwise by varying the thickness of a homogeneous film of a chromium compound provided on a transparent substrate sheet. A process for producing a gradation mask having spatially stepped transmittance in at least three steps including substantially 0% and substantially 100%, including the steps of: forming on a transparent substrate sheet a homogeneous film of a chromium compound in a thickness enough to have a transmittance of at least 0%; removing the chromium compound film in predetermined areas by etching; and reducing the thickness of the remaining chromium compound film in predetermined areas by etching to such an extent that the transmittance is a predetermined intermediate value. A gradation mask having spatially stepped transmittance in at least three steps including substantially 0% and substantially 100%, wherein the area having a transmittance of at least substantially 0% has a predetermined transmittance other than 0% and 100% and includes a semitransparent film provided in a fine repeating pattern on a transparent substrate sheet. The semitransparent film in a fine repeating pattern is provided in such a manner that the phase difference is substantially the half-wavelength of a wavelength used or a value obtained by multiplying the half-wavelength by an odd number.