公开(公告)号：US20190355388A1

公开(公告)日：2019-11-21

申请号：US16526299

申请日：2019-07-30

Applicant: Panasonic Intellectual Property Management Co., Ltd.

Inventor： YOSHIHIRO KAWASAKI ,  HIROKI KOBAYASHI ,  YU TOKORO

IPC: G11B7/24035 ,  G11B7/007

Abstract: An optical disc is formed by bonding a first information recording medium to a second information recording medium. The first information recording medium includes a first substrate having opposed first and second surfaces, at least one dielectric film, at least one recording film, and a cover layer. The second information recording medium includes a second substrate having opposed third and fourth surfaces, at least one dielectric film, at least one recording film, and a cover layer. The second surface of the first substrate is bonded to the fourth surface of the second substrate. At least one of the second surface or the fourth surface includes a depression and a projection. The depression is formed in a thickness direction of the optical disc. The projection is provided inside the depression at a predetermined distance or longer from an outer circumferential edge of the depression in a radial direction of the optical disc.