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:
Feb. 01, 2000
Filed:
Sep. 26, 1996
Mitsuo Takahashi, Matsudo, JP;
Katsuyuki Yasuda, Funabashi, JP;
Seikoh Giken Co., Ltd., Matsudo, JP;
Abstract
A stamper plate attaching/detaching device of an injection mold for forming an optical disc substrate wherein a stamper plate is supported in a cavity which is formed by a cavity side disc cavity plate, a movable disc cavity plate, and a cavity ring. The stamper plate attaching/detaching device is equipped with a section for holding the outer circumferential rim of the stamper plate by means of the inner circumferential rim of the cavity ring, which inner circumferential rim is larger than the outer diameter of the stamper plate. A plurality of pairs of permanent magnets, which have magnetic poles in parallel with respect to a central line are buried, with phase differences, on the same radial line of the cavity side disc cavity plate and the movable disc cavity plate. The cavity ring rotates between a first angle position and a second angle position in relation to the cavity side disc cavity plate and the movable disc cavity plate.