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:
Oct. 26, 1999
Filed:
Dec. 03, 1996
Hoya Corporation, Tokyo, JP;
Abstract
In an injection compression molding method of a lens, in which a mold is closed to preserve a predetermined compressing margin in a cavity 3 for a lens, molten resin is injected and fed into the cavity 3 for the lens, and compressed for the aforementioned predetermined compressing margin before or after the injection and the feed of the molten resin is completed, the predetermined compressing margin (the degree of slightly opening S.sub.(-)) for producing a minus lens is molded is defined to be larger than the predetermined compressing margin (the degree of slightly opening S.sub.(+)) for producing a plus lens is molded. As a result, even when the minus lens is molded, the larger area of the cavity can be ensure and a flow property of the molten resin in the cavity is improved, so that the molten resin reached the inside of the cavity 3 flow through the central portion of the cavity 3 into the peripheral portion, with the result that the appearance of a weld mark in the central portion is avoided.