Methods and apparatus for rendering an optically encoded medium unreadable

• US 6,709,802 B2
• Filed: 11/28/2001
• Issued: 03/23/2004
• Est. Priority Date: 06/25/1998
• Status: Expired due to Fees

• Current Assignee: Flexplay Technologies
• Original Assignee: Flexplay Technologies
• Inventors: Zepp, Charles M., Norland, Kenneth S., Lawandy, Nabil M.
• Primary Examiner(s): ANGEBRANNDT, MARTIN J
• Application Number:
  US09/996,058
• Publication Number:
  US 20020076647A1
• Time in Patent Office: 846 Days
• Field of Search: 369/286, 369/283, 369/275.1, 430/19, 430/270.15, 430/270.1, 428/945, 428/64.4
• US Class Current: 430/270.15
• 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 20/00797 wherein the usage restriction limits the number of times a content can be reproduced, e.g. using playback counters
• CPC Class Codes: G11B 23/282 Limited play
• CPC Class Codes: G11B 23/505 of disk carriers
• CPC Class Codes: G11B 7/252 of layers other than recording layers
• CPC Class Codes: G11B 7/2534 polycarbonates [PC]
• CPC Class Codes: G11B 7/2542 consisting essentially of organic resins
• CPC Class Codes: G11B 7/2575 resins
• CPC Class Codes: G11B 7/2585 based on aluminium
• CPC Class Codes: Y10S 430/146 Laser beam

Abstract

Methods and apparatus are provided for making an optically readable media unreadable. The method includes steps of (a) providing the media with an optically activated mechanism that degrades the reflectivity of a surface wherein information is encoded; (b) exposing the media to optical radiation for reading out the information; and, during the step of exposing, (c) initiating the operation of the optically activated mechanism. In this embodiment the step of initiating includes steps of (d) generating singlet oxygen in a layer disposed on the media; and (e) reacting the singlet oxygen with a metal-containing layer for oxidizing the surface of the metal-containing layer, thereby degrading the reflectivity of the surface. In a further aspect the optically activated mechanism causes a defocusing of a readout beam, thereby degrading reflection of the readout beam from a surface wherein information is encoded. In another embodiment the method deforms a surface of the layer resulting in readout beam aberration or in an inability to correctly stay on track. In another embodiment a portion of the surface is removed to the atmosphere, such as by evaporation of sublimation. In this embodiment a layer of the media is comprised of a volatile component and at least one other component. Removing at least some of volatile component by evaporation or sublimation causes an increase in at least one of photoabsorption or scattering or surface roughness with the remaining component, thereby rendering at least a portion of encoded information of the media unreadable, or affecting the tracking operation.

Claims

1. A method for intentionally making an optically readable media unreadable by a play process, comprising steps of:

providing the media with an optically activated mechanism that degrades the reflectivity of a surface wherein information is encoded;

exposing the media to optical radiation for reading out the information; and

during the step of exposing, initiating the operation of the optically activated mechanism;

wherein the step of initiating comprises steps of,

generating singlet oxygen in a photoresponsive layer disposed on the media;

diffusing the singlet oxygen through a diffusion barrier that is disposed between the photoresponsive layer and a metal-containing layer; and

reacting the singlet oxygen with the metal-containing layer for oxidizing the surface of the metal-containing layer, thereby degrading the reflectivity of the surface.

2. A method for intentionally making an optically readable media permanently unreadable by a play process, comprising the steps of:

providing an optically readable media with an optically activated mechanism, said optically activated mechanism interferes with the ability of the play process to read at least a portion of a data encoded reflective layer on said optically readable media,

exposing the optically readable media to optical radiation for reading out information on said optically readable media, said information encoded on said data encoded reflective layer; and

during the step of exposing, initiating the operation of the optically activated mechanism, wherein the step of initiating comprises;

generating an optically intensity gradient in a layer disposed on the optically readable media, wherein said layer comprises a first surface and a second surface, said first surface is unconstrained; and

in response to the generated optical intensity gradient, deforming said first surface of the layer, said first surface deformation making said at least a portion of said data encoded reflective layer unreadable by the play process.

3. A method as in claim 2, wherein the step of providing provides the layer so as to comprise an azobenzene containing polymer.

4. A method as in claim 2, wherein the step of initiating is comprised of steps of:

irradiating a photocurable polymer region that comprises the media; and

in response to the irradiation, photopolymerizing the polymer, thereby changing an index of refraction of the polymer resulting in readout beam aberration.

5. An optically readable media capable of intentionally being made unreadable by a play process, said media comprising

an optically activated mechanism that is responsive to light used to readout information for degrading the reflectivity of a surface wherein the information is encoded, wherein said mechanism is comprised of a photosenistizer compound for reacting with oxygen molecules that are present within a second layer for generating singlet oxygen in the second layer, the singlet oxygen reacting with said data encoded reflective layer for oxidizing the surface of said data encoded reflective layer, thereby degrading the reflectivity of the surface of said data encoded reflective layer.

6. An optically readable media capable of intentionally being made unreadable by a play process, said media comprising an optically activated mechanism that is responsive to light used to readout information for degrading the reflectivity of a surface wherein the information is encoded, wherein said mechanism is comprised of a photosensitizer compound for reacting with oxygen molecules that are present within a layer for generating singlet oxygen in the layer, the singlet oxygen reacting with a metal-containing layer for oxidizing the surface of the metal-containing layer, thereby degrading the reflectivity of the surface;

the optically readable media further comprising a diffusion barrier disposed between said layer and said metal-containing layer.

7. An optically readable media capable of intentionally being made permanently unreadable by a play process, said media comprising:

an optically activated mechanism that is responsive to light used to readout information from a data encoded reflective layer, said optically activated mechanism defocuses a readout beam, thereby making at least a portion of said data encoded reflective layer unreadable by said readout beam, wherein said optically activated mechanism is comprised of a layer of polymer that is responsive to an optical intensity gradient generated by said readout beam for deforming an unconstrained surface of said layer, resulting in readout beam aberration.

8. A media as in claim 7, wherein said layer comprises an azobenzene containing polymer.

9. A media as in claim 7, wherein said mechanism is comprised of at least one region comprised of photoresponsive polymer that is responsive to the readout beam for being photopolymerized, thereby changing an index of refraction of the photocurable polymer resulting in readout beam aberration.

10. A method for intentionally making an optically readable media permanently unreadable, comprising steps of:

providing an optically readable media with a data encoded reflective layer, said data encoded reflective layer readable by a readout beam;

providing the optically readable media with a surface layer having a planar surface topography, said surface layer preceding said data encoded reflective layer in the optical path of the readout beam; and

subsequent to or during a first readout of the optically readable media, modifying at least a portion of the planar surface topography to non-planar surface topography by the use of a photresponsive polymer and an optical intensity gradient that interacts with the photresponsive polymer for modifying the planar surface topography to the non-planar surface topography, wherein a deviation of the non-planar surface layer topography from the planar surface layer topography is sufficient to detrimentally affect at least a tracking operation of a readout device that generates the readout beam.

11. A method for making a limited play optically readable media, said method comprising the steps of:

providing an optically readable media with a data encoded reflective layer, said data encoded reflective layer readable by an optically readable media reading device, said optically readable media reading device comprising a reading beam;

providing an optically readable media with an optically activated mechanism, said optically activated mechanism comprising a layer with a first surface and a second surface, wherein said first surface is unconstrained, said layer preceding said data encoded reflective layer in the optical path of the reading beam of the optically readable media reading device;

wherein said optically activated mechanism deforms said first surface of said layer in response to said reading beam of said optically readable media reading device, said deformation inhibits the ability of said reading device to read at least a portion of said data encoded reflective layer on said optically readable media.