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:
Jul. 13, 1999
Filed:
Nov. 03, 1997
Hikaru Ishikawa, Tokyo, JP;
Kunio Machida, Tokyo, JP;
Bridgestone Corporation, Tokyo, JP;
Abstract
A method is provided for manufacturing an optical plastic article formed of a plastic resin composition and having a homogeneous construction and a surface shape within a predetermined dimensional accuracy. A first step includes injection molding melted resin of the plastic resin composition into a mold cavity to produce a primary molding. A second step includes injection molding melted resin of the plastic resin composition which is the same as in the first step over at least a portion of the primary molding to form a secondary molding melt-welded to the primary molding and having the surface shape within the predetermined dimensional accuracy. The secondary molding has a secondary molding maximum thickness less than a limit thickness at which shrinkage exceeds limits of the predetermined dimensional accuracy. The optical plastic article has an optical plastic article thickness defined by the primary molding and the secondary molding greater than the limit thickness. The primary molding is preferably preheated prior to the secondary molding being melt-welded thereto and can have a thickness greater than the limit thickness.