Optical disk, method for recording and reproducing write-once information on and from optical disk, optical disk reproducing device, optical disk recording and reproducing device, device for recording write-once information on optical disk, and optical disk recording device

• US 20010021144A1
• Filed: 04/12/2001
• Published: 09/13/2001
• Est. Priority Date: 12/19/1996
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Oshima, Mitsuaki, Gotoh, Yoshiho, Tanaka, Shin-ichi, Koishi, Kenji, Moriya, Mitsurou, Murakami, Motoyoshi, Takemura, Yoshinari, Miyatake, Norio, Konishi, Shinichi
• Granted Patent: US 6,584,046 B2
• Time in Patent Office: Days
• US Class Current: 369/13.02
• CPC Class Codes: G06T 1/0021 Image watermarking
• CPC Class Codes: G06T 2201/0064 for copy protection or copy management, e.g. CGMS, copy only once, one-time copy
• CPC Class Codes: G11B 11/10506 by modulating only the light beam of the transducer
• CPC Class Codes: G11B 11/10515 Reproducing compensating pit shift G11B11/1053
• CPC Class Codes: G11B 11/10584 characterised by the form, e.g. comprising mechanical protection elements
• CPC Class Codes: G11B 11/10595 Control of operating function
• 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 20/00123 the record carrier being identified by recognising some of its unique characteristics, e.g. a unique defect pattern serving as a physical signature of the record carrier
• CPC Class Codes: G11B 20/00166 involving measures which result in a restriction to authorised contents recorded on or reproduced from a record carrier, e.g. music or software
• CPC Class Codes: G11B 20/00181 using a content identifier, e.g. an international standard recording code [ISRC] or a digital object identifier [DOI]
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00231 wherein the key is obtained from a local external medium, e.g. a card
• CPC Class Codes: G11B 20/0026 the key being stored as a barcode
• CPC Class Codes: G11B 20/00268 said barcode being recorded in a burst cutting area [BCA]
• CPC Class Codes: G11B 20/00347 wherein the medium identifier is used as a key
• CPC Class Codes: G11B 20/00876 wherein physical copy protection means are attached to the medium, e.g. holograms, sensors, or additional semiconductor circuitry
• CPC Class Codes: G11B 20/00884 involving a watermark, i.e. a barely perceptible transformation of the original data which can nevertheless be recognised by an algorithm
• CPC Class Codes: G11B 20/10 Digital recording or reproducing
• CPC Class Codes: G11B 20/1217 on discs
• CPC Class Codes: G11B 20/1258 where blocks are arranged within multiple radial zones, e.g. Zone Bit Recording or Constant Density Recording discs, MCAV discs, MCLV discs
• CPC Class Codes: G11B 2020/122 : Burst cutting area [BCA]
• CPC Class Codes: G11B 2020/1244 : CAV zone, in which a constant angular velocity is used
• CPC Class Codes: G11B 2020/1245 : CLV zone, in which a constant linear velocity is used
• CPC Class Codes: G11B 23/281 : by changing the physical properties of the record carrier
• CPC Class Codes: G11B 23/288 : Protecting disks from being written or overwritten
• CPC Class Codes: G11B 23/40 : Identifying or analogous means applied to or incorporated in the record carrier and not intended for visual display simultaneously with the playing-back of the record carrier, e.g. label, leader, photograph
• CPC Class Codes: G11B 7/0037 : with discs
• CPC Class Codes: G11B 7/0045 : Recording G11B7/006, G11B7/0065 take precedence
• CPC Class Codes: G11B 7/00736 : Auxiliary data, e.g. lead-in, lead-out, Power Calibration Area [PCA], Burst Cutting Area [BCA], control information sector headers or adresses in prepits G11B7/00745; address data in track wobble G11B7/24082
• 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

Abstract

An optical disk storing write-once information usable for protecting the copyright of the software by preventing the duplication, unauthorized use, etc., of the software. In the optical disk, a recording layer (213) is formed on a disk substrate (211) with a dielectric layer (212) inbetween. Then, an intermediate dielectric layer (214) and a reflecting layer (215) are successively laminated upon the recording layer (213), and an overcoat layer (216) is formed on the surface of the reflecting layer (215). A plurality of BCA (one of write-once identification information systems) sections (220a and 220b) are recorded by lowering the vertical magnetic anisotropy of the recording layer (213). At the time of reproduction, the write-once information is detected from differential signals.

Claims

1. An optical disk comprising:

a disk substrate; and

a recording layer on the disk substrate, the recording layer including a magnetic film with magnetic anisotropy in a direction perpendicular to a surface of the magnetic film;

wherein

the optical disk stores write-once information formed by first recording areas and second recording areas in a pre-determined portion of said recording layer;

a magnetic anisotropy in a direction perpendicular to a surface of the second recording areas is smaller than a magnetic anisotropy in a direction perpendicular to a surface of the first recording areas;

the second recording areas are formed as stripe-shaped marks that are oblong in a radial direction of the disk; and

a plurality of the marks is arranged in a circumferential direction of the disk, the arrangement being based on a modulation signal of the write-once information.

2. The optical disk according to

claim 1

, further comprising an identifier for indication whether there is a row of a plurality of marks arranged in a circumferential direction of the disk.

3. The optical disk according to

claim 2

, wherein the identifier indicating the row of marks is stored among control data.

4. The optical disk according to

claim 1

, wherein the pre-determined portion comprising write-once information is at an inner perimeter portion of the disk.

5. The optical disk according to

claim 1

, wherein a difference between a luminous energy that is reflected from the first recording areas and a luminous energy that is reflected from the second recording areas is below a certain value.

6. The optical disk according to

claim 5

, wherein the difference between luminous energy that is reflected from the first recording areas and luminous energy that is reflected from the second recording areas is not more than 10%.

7. The optical disk according to

claim 1

, wherein a difference between an average refractive index of the first recording areas and an average refractive index of the second recording areas is not more than 5%.

8. The optical disk according to

claim 1

, wherein the magnetic anisotropy of the magnetic film of the second recording areas in an in-plane direction is dominant.

9. The optical disk according to

claim 1

, wherein at least a portion of the magnetic film of the second recording areas is crystallized.

10. The optical disk according to

claim 1

, wherein said recording layer comprises a multilayer magnetic film.

11. An optical disk comprising:

a disk substrate; and

a recording layer on the disk substrate, the recording layer including a film that can be reversibly changed between two optically detectable states;

wherein

the optical disk stores write-once information formed by first recording areas and second recording areas in a pre-determined portion of said recording layer;

a luminous energy that is reflected from the first recording areas differs from a luminous energy that is reflected from the second recording areas;

the second recording areas are formed as stripe-shaped marks that are oblong in a radial direction of the disk; and

a plurality of the marks is arranged in a circumferential direction of the disk, the arrangement being based on a modulation signal for the write-once information.

12. The optical disk according to

claim 11

, further comprising an identifier for indication whether there is a row of a plurality of marks arranged in a circumferential direction of the disk.

13. The optical disk according to

claim 12

, wherein the identifier indicating the row of marks is stored among control data.

14. The optical disk according to

claim 11

, wherein the pre-determined portion comprising write-once information is at an inner perimeter portion of the disk.

15. The optical disk according to

claim 11

, wherein the recording layer undergoes a reversible phase change between a crystalline phase and an amorphous phase, depending on irradiation conditions for irradiated light.

16. The optical disk according to

claim 15

, wherein the difference between luminous energy that is reflected from the first recording areas and luminous energy that is reflected from the second recording areas is at least 10%.

17. The optical disk according to

claim 15

, wherein a difference between an average refractive index of the first recording areas and an average refractive index of the second recording areas is at least 5%.

18. The optical disk according to

claim 15

, wherein the second recording areas of said recording layer are in a crystalline phase.

19. The optical disk according to

claim 15

, wherein said recording layer comprises a Ge—

Sb—

Te alloy.

20. An optical disk whereon main information and write-once information is recorded, the write-once information being different for each disk, and the write-once information storing at least watermark production parameters for producing a watermark.

21. The optical disk according to

claim 20

, wherein the main information is recorded by providing convex-concave pits in a reflective layer, and the write-once information is recorded by partially removing the reflective layer.

22. The optical disk according to

claim 20

, wherein the main information and the write-once information are recorded by partially changing a reflection coefficient of a reflective layer.

23. The optical disk according to

claim 20

, wherein a recording layer comprises a magnetic layer with a magnetic anisotropy in a direction perpendicular to a surface of the magnetic layer, the main information is recorded by partially changing a magnetization direction of the recording layer, and the write-once information is recorded by partially changing the magnetic anisotropy in the direction perpendicular to the surface of the magnetic layer.

24. A method for recording write-once information onto an optical disk (a) comprising a disk substrate, and a recording layer on the disk substrate, including a magnetic film with a magnetic anisotropy in a direction perpendicular to a surface of the magnetic film;

and (b) storing write-once information formed by first recording areas and second recording areas in a pre-determined portion of said recording layer;

the method comprising forming the second recording areas as a plurality of stripe-shaped marks that are oblong in a radial direction of the disk in a circumferential direction of the disk by irradiating laser light based on a modulation signal of the write-once information in a circumferential disk direction in the pre-determined portion of said recording layer in a manner that a magnetic anisotropy in a direction perpendicular to a surface of the second recording areas becomes smaller than a magnetic anisotropy in a direction perpendicular to a surface of the first recording areas.

25. The recording method according to

claim 24

, wherein, when the second recording areas are formed, a laser light source is pulsed in accordance with a modulation signal of phase-encoded write-once information, and the optical disk or the laser light is rotated.

26. The recording method according to

claim 24

, wherein the optical disk further comprises a reflective layer and a protective layer on the disk substrate, and an intensity of laser light irradiated to form the second recording areas is smaller than an intensity of laser light destroying at least one of the disk substrate, the reflective layer and the protective layer.

27. The recording method according to

claim 24

, wherein an intensity of laser light irradiated to form the second recording areas is an intensity for crystallizing at least a portion of said recording layer.

28. The recording method according to

claim 24

, wherein an intensity of laser light irradiated to form the second recording areas is larger than an intensity of laser light for heating said recording layer to a Curie temperature.

29. The recording method according to

claim 24

, wherein an intensity of laser light irradiated to form the second recording areas is an intensity for making a magnetic anisotropy of the magnetic layer of the first recording areas in an in-plane direction dominant.

30. The recording method according to

claim 24

, wherein, with a unidirectional convergence focusing lens, rectangularly stripe-shaped laser light is irradiated onto said recording layer when the second recording areas are formed.

31. The recording method according to

claim 24

, wherein a light source of the laser light that is irradiated for forming the second recording areas is a YAG laser.

32. The recording method according to

claim 31

, wherein a magnetic field above a certain value is applied to said recording layer while irradiating laser light from the YAG laser.

33. The recording method according to

claim 32

, wherein the magnetic field applied to said recording layer is at least 5 kOe.

34. A method for recording write-once information onto an optical disk (a) comprising a disk substrate;

and on the disk substrate a recording layer comprising a film that can be reversibly changed between two optically detectable states; and

(b) storing write-once information formed by first recording areas and second recording areas in a pre-determined portion of said recording layer;

the method comprising forming the second recording areas as a plurality of stripe-shaped marks that are oblong in a radial direction of the disk in a circumferential direction of the disk by irradiating laser light based on a modulation signal of the write-once information in a circumferential disk direction in the pre-determined portion of said recording layer in a manner that a luminous energy of light reflected from the first recording areas differs from a luminous energy of light reflected from the second recording areas.

35. The recording method according to

claim 34

, wherein, when the second recording areas are formed, a laser light source is pulsed in accordance with a modulation signal of phase-encoded write-once information, and the optical disk or the laser light is rotated.

36. The recording method according to

claim 34

, wherein the optical disk further comprises a reflective layer and a protective layer on the disk substrate, and an intensity of laser light irradiated to form the second recording areas is smaller than an intensity of laser light destroying at least one of the disk substrate, the reflective layer and the protective layer.

37. The recording method according to

claim 34

, wherein an intensity of laser light irradiated to form the second recording areas is an intensity for crystallizing at least a portion of said recording layer.

38. The recording method according to

claim 34

, wherein, with a unidirectional convergence focusing lens, rectangularly stripe-shaped laser light is irradiated onto said recording layer when the second recording areas are formed.

39. The recording method according to

claim 35

, wherein a light source of the laser light that is irradiated for forming the second recording areas is a YAG laser.

40. A method for recording write-once information onto an optical disk, comprising:

producing a watermark based on a disk ID; and

overlapping the watermark on specific data to record it as write-once information.

41. A method for reproducing write-once information from an optical disk (a) comprising a disk substrate, and a recording layer on the disk substrate, the recording layer including a magnetic film with a magnetic anisotropy in a direction perpendicular to a surface of the magnetic film;

and (b) storing write-once information formed by first recording areas and second recording areas in a pre-determined portion of said recording layer, the first and second recording layers having different magnetic anisotropies in a direction perpendicular to a surface of the magnetic layer;

the method comprising;

irradiating linearly polarized laser light onto said pre-determined portion; and

detecting a change in a polarization orientation of light reflected from the optical disk or light transmitted through the optical disk.

42. The reproducing method according to

claim 41

, wherein the linearly polarized laser light is irradiated onto said pre-determined portion after magnetizing the recording layer of said pre-determined portion in one step by applying a magnetic field that is larger than a coercive force of the recording layer in said pre-determined portion.

43. The reproducing method according to

claim 41

, wherein the linearly polarized laser light is irradiated onto said pre-determined portion after aligning a magnetization of said recording layer of said pre-determined portion by applying a unidirectional magnetic field to said pre-determined portion while increasing the temperature of said recording layer in said predetermined portion above the Curie temperature by irradiating laser light of constant luminous energy.

44. A method for reproducing write-once information from an optical disk (a) comprising a disk substrate;

and a recording layer on the disk substrate, the recording layer including a film that can be reversibly changed between two optically detectable states; and

(b) storing write-once information formed by first recording areas and second recording areas with different reflection coefficients in a pre-determined portion of said recording layer;

the method comprising;

irradiating focused laser light onto said pre-determined portion; and

detecting a change in a luminous energy reflected from the disk.

45. An apparatus for reproducing optical disks comprising (a) a main information recording area for recording main information;

and (b) an auxiliary signal recording area overlapping partly with the main information recording area for recording a phase-encoding modulated auxiliary signal that overlaps a signal of main information, the apparatus comprising;

means for reproducing a main information signal in the main information recording area with an optical head;

first decoding means for decoding a main information signal to obtain main information data;

means for reproducing a mixed signal comprising a main information signal in said auxiliary signal recording area and the auxiliary signal as a reproduction signal with the optical head;

frequency separation means for suppressing the main information signal in the reproduction signal to obtain the auxiliary signal; and

second decoding means for phase-encoding decoding the auxiliary signal to obtain the auxiliary data.

46. The apparatus according to

claim 45

, wherein the frequency separation means is a low-frequency component separation means for suppressing high frequency components in the reproduction signal reproduced with the optical head to obtain a low frequency reproduction signal, the apparatus further comprises:

a second-slice-level setting portion for producing a second slice level from said low-frequency reproduction signal; and

a second-level slicer for slicing the low-frequency reproduction signal at the second slice level to obtain a binarized signal;

wherein the apparatus phase-encoding decodes the binarized signal to obtain the auxiliary data.

47. The apparatus according to

claim 46

, wherein

the second-slice-level setting portion comprises auxiliary low-frequency component separation means with a time constant that is larger than that of the low-frequency component separation means;

a reproduction signal reproduced with the optical head or a low-frequency reproduction signal obtained with the low-frequency component separation means is entered into the auxiliary low-frequency component separation means; and

components with frequencies lower than the low-frequency reproduction signal are extracted to obtain a second slice level.

48. The apparatus according to

claim 45

, further comprising:

frequency transformation means for transforming a main information signal included in a reproduction signal reproduced with the optical head from a time domain into a frequency domain to produce a first transformation signal;

means for producing a mixed signal, wherein auxiliary information has been added or superposed to the first transformation signal;

frequency inverse-transformation means for transforming the mixed signal from the frequency domain to the time domain to produce a second transformation signal.

49. An apparatus for reproducing optical disks, wherein an optical head irradiates linearly polarized light onto an optical disk, and a change of a polarization orientation of light that is transmitted or reflected from the optical disk is detected in accordance with a recording signal on the optical disk;

and the apparatus comprises;

means for moving, when necessary, the optical head into a predetermined portion of the optical disk where write-once information is stored, and

means for reproducing the write-once information after detecting a change of a polarization orientation of light that is transmitted or reflected from the pre-determined portion.

50. The apparatus according to

claim 49

, further comprising means for detecting an identifier indicating whether write-once information within control data of the optical disk is present, the indication being based on a detection signal of detection light that is received with at least one photodetector of the optical head or on an all-sum signal of detection signals of detection light that is received with a plurality of photo-detectors of the optical head,

wherein to detect the identifier and to verify whether write-once information is present, the optical head is moved to the pre-determined portion of the optical disk where write-once information is stored, when necessary.

51. The apparatus according to

claim 49

, further comprising decoding means for phase-encoding decoding during reproduction of the write-once information.

52. An apparatus for reproducing optical disks whereon main information is stored and write-once information that differs for each disk is stored, the apparatus comprising:

a signal reproduction portion for reproducing the main information;

a write-once information reproduction portion for reproducing the write-once information; and

a watermark attaching portion for producing a watermark signal based on the write-once information, adding the watermark signal to the main information and giving it out.

53. The apparatus according to

claim 52

, wherein the write-once information is recorded by partially changing a reflection coefficient of a recording layer on the optical disk.

54. The apparatus according to

claim 52

wherein a recording layer of the optical disk comprises a magnetic film having a magnetic anisotropy that is perpendicular to a film surface;

and

write-once information is stored by partially changing the perpendicular magnetic anisotropy of the magnetic film.

55. The apparatus according to

claim 52

wherein a watermark attaching portion overlaps a signal of the main information with auxiliary information comprising a watermark.

56. The apparatus according to

claim 52

, further comprising:

a frequency transformation means for producing a first transformation signal by transforming a signal of main information from a time domain into a frequency domain;

means for producing a mixed signal by adding or superposing write-once information and the first transformation signal; and

frequency inverse-transformation means for producing a second transformation signal by transforming the mixed signal from the frequency domain into the time domain.

57. The apparatus according to

claim 52

, further comprising:

an MPEG decoder for expanding main information into a video signal; and

means for inputting the video signal into the watermark attaching portion.

58. The apparatus according to

claim 57

, further comprising a watermark reproduction portion for reproducing watermarks;

wherein

said MPEG decoder and said watermark reproduction portion both comprise a mutual authentication portion; and

encrypted main information is sent and decrypted only if the mutual authentication portions authenticate each other.

59. The apparatus according to

claim 57

wherein a decoded signal of main information that is compounded with an encryption decoder is input into the MPEG decoder.

60. The apparatus according to

claim 59

, further comprising a watermark reproduction portion for reproducing watermarks;

wherein

an encryption decoder and said watermark reproduction portion both comprise a mutual authentication portion; and

encrypted main information is sent and decrypted only if the mutual authentication portions authenticate each other.

61. An apparatus for recording and reproducing optical disks whereon information can be recorded, erased and reproduced and whereon main information is stored on a main recording area of a recording layer of the optical disks using a recording circuit and an optical head, the apparatus comprising:

means for reproducing write-once information, that is recorded onto a pre-determined portion of the recording layer, using a signal output portion of the optical head, which detects the write-once information as a change of a polarization orientation;

means for recording the main information onto the main recording area as encrypted information that is encrypted with an encryption encoder using the write-once information; and

means for reproducing the main information by reproducing the write-once information with the signal output portion of the optical head and decoding the encrypted information as a decryption key in an encryption decoder.

62. An apparatus for recording and reproducing optical disks whereon main information is recorded onto a main recording area of a recording layer of the optical disks using a recording circuit and an optical head, the apparatus comprising:

a watermark attaching portion for adding a watermark to the main information;

wherein

write-once information that is stored in a pre-determined portion of the recording layer is reproduced with the optical head;

the reproduced write-once information is added to the main information as a watermark with said watermark attaching portion;

the main information including the watermark is recorded onto the main recording area.

63. The apparatus according to

claim 62

, wherein the main information is recorded by partially changing a reflection coefficient of the recording layer.

64. The apparatus according to

claim 62

wherein the recording layer comprises a magnetic film having a magnetic anisotropy that is perpendicular to a film surface;

and

main information is stored by partially changing a magnetization direction of the magnetic film.

65. The apparatus according to

claim 64

wherein the main information and the write-once information are reproduced by detecting a change of a magnetization orientation of the recording layer or a change of the perpendicular anisotropy of the recording layer with an optical head as a change of a polarization orientation.

66. The apparatus according to

claim 62

wherein a watermark attaching portion overlaps a signal of the main information with auxiliary information comprising a watermark.

67. The apparatus according to

claim 62

, further comprising:

a frequency transformation means for producing a first transformation signal by transforming a signal of main information from a time domain into a frequency domain;

means for producing a mixed signal by adding or superposing write-once information and the first transformation signal; and

frequency inverse-transformation means for producing a second transformation signal by transforming the mixed signal from the frequency domain into the time domain.

68. The apparatus according to

claim 62

, further comprising:

an MPEG decoder for expanding main information into a video signal; and

means for inputting the video signal into the watermark attaching portion.

69. The apparatus according to

claim 68

, further comprising a watermark reproduction portion for reproducing watermarks;

wherein

said MPEG decoder and said watermark reproduction portion both comprise a mutual authentication portion; and

encrypted main information is sent and decrypted only if the mutual authentication portions authenticate each other.

70. The apparatus according to

claim 68

wherein a decoded signal of main information that is compounded with an encryption decoder is input into the MPEG decoder.

71. The apparatus according to

claim 70

, further comprising a watermark reproduction portion for reproducing watermarks;

wherein

said encryption decoder and said watermark reproduction portion both comprise a mutual authentication portion; and

encrypted main information is sent and decrypted only if the mutual authentication portions authenticate each other.

72. An apparatus for recording write-once information onto an optical disk storing main information, the apparatus comprising means for recording auxiliary information comprising at least one of a disk ID and watermark production parameters.

73. The apparatus according to

claim 72

, wherein the main information is stored by providing convex-concave pits in a reflection film of the optical disk, and the auxiliary information is stored by partially erasing the reflection film.

74. The apparatus according to

claim 72

, wherein the main information is stored by partially changing a reflection coefficient of a recording layer of the optical disk, and the auxiliary information is stored by partially changing a reflection coefficient of the recording layer of the optical disk.

75. The apparatus according to

claim 72

wherein a recording layer of the optical disk comprises a magnetic film having a magnetic anisotropy that is perpendicular to a film surface;

main information is stored by partially changing a magnetization direction of the magnetic film; and

auxiliary information is stored by partially changing the perpendicular magnetic anisotropy of the magnetic film.

76. An apparatus for recording optical disks storing main information, comprising:

means for producing a watermark based on auxiliary information comprising a disk ID; and

means for recording data, which consists of certain data to which the watermark has been superposed.