Optical recording medium and reproducing method for the same

• US 5,818,812 A
• Filed: 04/15/1996
• Issued: 10/06/1998
• Est. Priority Date: 09/22/1995
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Fujitsu Limited
• Inventors: Moribe, Mineo, Yoshioka, Makoto
• Primary Examiner(s): Edun, Muhammad N.
• Application Number:
  US08/632,014
• Time in Patent Office: 904 Days
• Field of Search: 369/275.2, 369/275.1, 369/275.3, 369/275.4, 369/275.5, 369/280, 369/47, 369/48, 369/53, 369/54, 369/58, 369/59, 369/13, 369/32
• US Class Current: 369/47.15
• CPC Class Codes: G11B 11/10595 Control of operating function
• CPC Class Codes: G11B 19/02 Control of operating function, e.g. switching from recording to reproducing
• CPC Class Codes: G11B 19/12 by sensing distinguishing features of or on records, e.g. diameter end mark
• 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 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00347 wherein the medium identifier is used as a key
• CPC Class Codes: G11B 20/00557 wherein further management data is encrypted, e.g. sector headers, TOC or the lead-in or lead-out areas
• CPC Class Codes: G11B 20/00586 said format change concerning the physical format of the recording medium
• CPC Class Codes: G11B 23/284 on the record carrier
• CPC Class Codes: G11B 7/0037 with discs
• CPC Class Codes: G11B 7/005 Reproducing G11B7/0065 takes precedence
• CPC Class Codes: G11B 7/007 Arrangement of the information on the record carrier, e.g. form of tracks , actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track

Abstract

The invention provides an optical recording medium in which a medium judge code for confirming genuineness of the medium as well as a medium identification code peculiar to the medium are recorded as labels for preventing illegal copy of the optical recording medium and illegal usage of recorded data therein, so as to decrease the degree of degradation of the area for the medium identification code, and also provides a reproducing method for the optical recording medium.

Claims

1. An optical recording medium, comprising:

a substrate; and

a recording film on the substrate,

wherein the recording film includes an unrewritable medium identification code peculiar to the optical recording medium and is recorded through irreversible change of the recording film, and an unrewritable medium judge code for judging whether or not the medium identification code is recorded in the optical recording medium.

2. The optical recording medium according to claim 1, wherein the medium judge code is recorded in the form of irregular pits.

3. The optical recording medium according to claim 1, wherein the medium judge code is recorded through irreversible change of the recording film.

4. The optical recording medium according to claim 3, wherein the irreversible change of the recording film is a change of a magnetization characteristic caused by applying a high energy.

5. The optical recording medium according to claim 3, wherein the irreversible change of the recording film is deformation caused by applying a high energy.

6. The optical recording medium according to claim 1, wherein the recording film includes a magneto-optical recording area where data can be recorded by changing a magnetization direction through beam irradiation and application of an external magnetic field.

7. The optical recording medium according to claim 1, wherein the recording film includes a phase-change type recording area which is made of a material having different light reflectance in accordance with a phase state thereof.

8. A method for reproducing an optical recording medium including recording film on a substrate, comprising:

a first step of conducting, an erasing operation for erasing rewritably recorded data, on an area where a medium identification code, which is information peculiar to the optical recording medium and is recorded on the recording film through irreversible change of the recording film, is recorded;

a second step of reproducing the area for the medium identification code after the first step;

a third step of reproducing an area for a medium judge code, which is unrewritably recorded on the recording film; and

a fourth step of terminating a reproducing process of the optical recording medium in accordance with a result obtained in the second or third step.

9. The reproducing method for an optical recording medium according to claim 8, wherein the fourth step includes a step of judging whether or not the result obtained in the third step is identical to the medium judge code so as to terminate the reproducing process of the optical recording medium when the result is not identical to the medium judge code.

10. The reproducing method for an optical recording medium according to claim 8,

wherein the third step includes a step of conducting the erasing operation on the area for the medium judge code before reproducing the area for the medium judge code and recording a predetermined code on the area where the erasing operation has been conducted;

and

the fourth step includes a step of judging whether or not the result obtained in the third step is identical to the predetermined code so as to terminate the reproducing process of the optical recording medium when the result is identical to the predetermined code.

17. A computer readable optical recording medium according to claim 10, wherein said judge code is recorded through irreversible change of the recording film, and said medium judging program includes:

a step of conducting an erasing operation for erasing rewritably recorded data, on an area where the medium judge code is recorded;

a step of recording a predetermined code in the area where the erasing operation for the medium judge code was performed;

a step of reproducing the medium judge code from the area in which the predetermined code was recorded;

a step of judging whether the medium judge code is identical to the predetermined code; and

a step of terminating a reproducing process of the optical recording medium when the medium judge code is identical to the predetermined code.

18. A computer readable optical recording medium according to claim 17, wherein the recording medium includes a magneto-optical recording area in which data is recorded by changing a magnetization direction through beam irradiation and application of an external magnetic field.

19. A computer readable optical recording medium according to claim 17, wherein the recording medium includes a phase-change type recording area which is made of a material having a different light reflectance in accordance with a phase state thereof.

20. A computer readable optical recording medium according to claim 17, wherein on the recording film is recorded:

a recording program including;

a step of reproducing the medium identification code;

a step of encoding data using the medium identification code; and

a step of recording the encoded data on the recording film.

11. A computer readable optical recording medium having an unrewritable medium identification code peculiar to the optical recording medium, the unrewritable medium identification being recorded through irreversible change of a recording film, the recording medium further having an unrewritable medium judge code, recorded in the form of irregular pits, for judging whether or not the medium identification code is recorded in the optical recording medium, said recording medium further comprising:

a reproducing program including;

a step of conducting an erasing operation for erasing rewritably recorded data, on an area where the medium identification code is recorded;

a step of reproducing the medium identification code after the erasing operation;

a step of reproducing data recorded on the optical recording medium; and

a step of decoding the reproduced data using the reproduced medium identification code; and

a medium judging program including;

a step of reproducing the medium judge code from the recording medium;

a step of judging whether the medium judge code is identical to the medium identification code; and

a step of terminating a reproducing process of the optical recording medium when the medium judge code is not identical to the medium identification code.

12. A computer readable optical recording medium according to claim 11, wherein the recording medium includes a magneto-optical recording area in which data is recorded by changing a magnetization direction through beam irradiation and application of an external magnetic field.

13. A computer readable optical recording medium according to claim 11, wherein on the recording film is recorded:

a recording program including;

a step of reproducing the medium identification code;

a step of encoding data using the medium identification code; and

a step of recording the encoded data on the recording film.

14. A computer readable optical recording medium according to claim 11, wherein said medium judging program includes:

a step of conducting an erasing operation for erasing rewritably recorded data, on an area where the medium judge code is recorded;

a step of recording a predetermined code in the area where the erasing operation for the medium judge code was performed;

a step of reproducing the medium judge code from the area in which the predetermined code was recorded;

a step of judging whether the medium judge code is identical to the predetermined code; and

a step of terminating a reproducing process of the optical recording medium when the medium judge code is identical to the predetermined code.

15. A computer readable optical recording medium according to claim 14, wherein the recording medium includes a phase-change type recording area which is made of a material having a different light reflectance in accordance with a phase state thereof.

16. A computer readable optical recording medium according to claim 14, wherein on the recording film is recorded:

a recording program including;

a step of reproducing the medium identification code;

a step of encoding data using the medium identification code; and

a step of recording the encoded data on the recording film.

21. A method for reproducing data from a computer readable optical recording medium having an unrewritable medium identification code peculiar to the optical recording medium, the unrewritable medium identification being recorded through irreversible change of a recording film, the recording medium further having an unrewritable medium judge code, recorded in the form of irregular pits, for judging whether or not the medium identification code is recorded in the optical recording medium, said reproducing method comprising the steps:

conducting an erasing operation for erasing rewritably recorded data, on an area where the medium identification code is recorded;

reproducing the medium identification code after the erasing operation;

reproducing the medium judge code from the recording medium;

judging whether the medium judge code is identical to the medium identification code, and if so;

reproducing data recorded on the optical recording medium; and

decoding the reproduced data using the reproduced medium identification code.

22. A method for reproducing data from a computer readable optical recording medium having an unrewritable medium identification code peculiar to the optical recording medium, the unrewritable medium identification being recorded through irreversible change of a recording film, the recording medium further having an unrewritable medium judge code, recorded in the form of irregular pits, for judging whether or not the medium identification code is recorded in the optical recording medium, said reproducing method comprising the steps:

conducting an erasing operation for erasing rewritably recorded data, on an area where the medium identification code is recorded;

conducting an erasing operation for erasing rewritably recorded data, on an area where the medium judge code is recorded;

recording a predetermined code in the area where the erasing operation for the medium judge code was performed;

reproducing information from the area in which the predetermined code was recorded;

judging whether the reproduced information is identical to the predetermined code, and if not;

reproducing the medium identification code;

reproducing data recorded on the optical recording medium; and

decoding the reproduced data using the reproduced medium identification code.

23. A method for reproducing data from a computer readable optical recording medium having an unrewritable medium identification code peculiar to the optical recording medium and an unrewritable medium judge code for judging whether or not the medium identification code is recorded in the optical recording medium, the respective unrewritable codes being recorded through irreversible change of a recording film, said reproducing method comprising the steps:

conducting an erasing operation for erasing rewritably recorded data, on an area where the medium identification code is recorded;

conducting an erasing operation for erasing rewritably recorded data, on an area where the medium judge code is recorded;

recording a predetermined code in the area where the erasing operation for the medium judge code was performed;

reproducing information from the area in which the predetermined code was recorded;

judging whether the reproduced information is identical to the predetermined code, and if not;

reproducing the medium identification code;

reproducing data recorded on the optical recording medium; and

decoding the reproduced data using the reproduced medium identification code.