Optical recording disc capable of preventing illegal copy

• US 6,108,296 A
• Filed: 08/19/1998
• Issued: 08/22/2000
• Est. Priority Date: 08/20/1997
• Status: Expired due to Term

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Kajiyama, Seiji, Tada, Kouichi, Tsuchiya, Youichi, Torazawa, Kenji
• Primary Examiner(s): DINH, TAN X
• Application Number:
  US09/136,458
• Time in Patent Office: 734 Days
• Field of Search: 369/275.3, 369/275.4, 369/275.2, 369/84, 369/58, 369/44.26, 360/60
• US Class Current: 369/275.4
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 23/281 by changing the physical properties of the record carrier
• CPC Class Codes: G11B 23/284 on the record carrier
• CPC Class Codes: G11B 7/24 Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the arrangement of information on the carrier G11B7/007
• CPC Class Codes: G11B 7/24085 Pits
• CPC Class Codes: G11B 7/261 Preparing a master, e.g. exposing photoresist, electroforming

Abstract

Micro-pits or micro-pit strings, which are disabled precise copying by means of illegal copying described above and enable signals different from signals of a normal disc to be detected in case of failure in precise copying, are recorded in a copy protected area of an optical disc beforehand. A read unit checks the copy protected area and determines a loaded disc is legal disc or illegally copied disc. If illegal, reading is prohibitted.

Claims

1. An optical disc having a copy protected area, wherein the copy protected area being provided with micro-pits which are broken by copying the optical disc.

2. An optical disc having a copy protected area, wherein the copy protected area being provided with micro-pit strings which are broken by copying the optical disc.