Molded lens having an outer circumference and first and second optical surfaces with cut off peripheral portions, and molding die for the molded lens

• Main Authors: ITOH TERUHIKO, SAWAGAMI AKIRA, KOJIMA TOSHIYUKI
• Format: Patent
• Language: English
• Published: 01.09.2005
• Edition: 7
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULARARTICLES; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PERFORMING OPERATIONS; PHYSICS; PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCESIN A PLASTIC STATE; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

A molded lens used in an optical pickup device provided with a plane of incidence having a first optical surface and a plane of emergence having a second optical surface, and a form of an outer circumference of the molded lens is formed by a first straight line portion which is in parallel substantially with a plane including an optical axis, a second straight line portion which is in parallel with the first straight line portion and is symmetric with the first straight line portion about the plane and by two circular arcs each connecting end portions of the first and second straight line portions. A part of a fringe of each of the first and second optical surfaces is substantially in a form of a circle whose center is on the optical axis is cut off by each of the first and second straight line portions.