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:
Apr. 13, 1999
Filed:
Feb. 21, 1997
Matthew Olen Kelley, Terre Haute, IN (US);
Han H Nee, Terre Haute, IN (US);
Michael Lee Mitchell, Terre Haute, IN (US);
James Arthur Thorp, III, Terre Haute, IN (US);
Sony Corporation, Tokyo, JP;
Digital Audio Disc Corporation, Terre Haute, IN (US);
Abstract
A molding apparatus for molding an optical component comprises first and second mold sections (20-26, 34) forming opposite sides of a mold cavity (40). The mold cavity has a peripheral edge (43) contacting the optical component during the molding process which is made to reduce the transfer of heat through the peripheral edge (43). In one embodiment of the invention, the peripheral edge is made from a titanium alloy (56) having thermal conductivity approximately 50% of a thermal conductivity of stainless steel. In another embodiment of the invention, the peripheral edge of the mold is made from a porous titanium material (56a) having a density substantially less than the solid titanium alloy. In a further embodiment of the invention, the peripheral edge of the mold is made from a polyimide (70) having oxygen atoms implanted in its surface. In a still further embodiment of the invention, the peripheral edge of the mold is the stainless steel (84) normally used in the mold, however, an annular ring of a polyimide (82) is disposed behind the peripheral edge of the mold cavity. All of the above embodiments provide insulating properties at the peripheral edge (43) of the mold to reduce birefringence but maintain the wear resistance properties of a steel mold to provide long life.