OBJECTIVE LENS, COUPLING ELEMENT, AND OPTICAL PICKUP DEVICE

摘要

Provided is an optical element suitable for an optical pickup device that uses optical disks having multiple information recording surfaces. A beam of light with wavelength ?1 that enters the effective diameter of the optical surface of the optical element is divided, and information can be recorded to or read from differing information recording surfaces while a coupling lens remains fixed, thereby allowing energy savings and also allowing the architecture of the optical pickup device to be simplified.