Optical information storage medium

Patent metadata

Field	Value
Publication number	US-10229709-B2
Application number	US-201615041928-A
Country	US
Kind code	B2
Filing date	Feb 11, 2016
Priority date	Jun 9, 2011
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

An optical information storage medium includes a multilayer film that includes a plurality of extruded alternating active data storage layers and buffer layers, which separate the active data storage layers. The active data storage layers and buffer layers have thicknesses that allow the active data storage layers to be writable by non-linear or threshold writing processes to define data voxels within the active data storage layers that are readable by an optical reading device.

First claim

Having described the invention, the following is claimed:

1. An optical information storage medium comprising a multilayer polymeric film that includes a plurality of coextruded alternating polymeric active data storage layers and polymeric buffer layers, which separate the active data storage layers, the active data storage layers including a fluorescent dye and/or semiconductor nanoparticles that undergo a permanent optically induced localized nonlinear or threshold change of fluorescence intensity when written by a single wavelength nonlinear or threshold optical writing process with excitation within the absorption band of the fluorescent dye and/or semiconductor nanoparticles and at least one data voxel written and confined within a discrete active data storage layer of the active storage layers by the single wavelength nonlinear or threshold optical writing process, the active data storage layers and buffer layers having thicknesses that allow the active data storage layers to be writable by the single wavelength nonlinear or threshold optical writing process with excitation within a single-photon absorption band of the fluorescent dye and/or semiconductor nanoparticles to define the at least one data voxel within the discrete active data storage layer that is readable by an optical reading device, wherein the buffer layers have an average thickness of 3 μm to about 100 μm.

2. An optical information storage medium comprising a multilayer polymeric film that includes a plurality of coextruded alternating polymeric active data storage layers and polymeric buffer layers, the active data storage layers configured to undergo a permanent photothermally induced localized nonlinear or threshold change of optical properties when written by a one photon or multi-photon optical writing process, the buffer layers separating the active data storage layers with sufficient thicknesses to axially confine at least one data voxel written by the optical writing process into a single discrete active data storage layer that is readable by an optical reading device, wherein the buffer layers have an average thickness of 3 μm to about 100 μm.

3. The medium of claim 2 , the change of optical properties including at least one of a change of absorption, fluorescence color, fluorescence intensity, absorption color, transparency, scattering, reflectivity, refractive index, phase, or polarization.

4. The medium of claim 2 , in the active data storage layers including a material that undergoes a change of fluorescence and/or reflectance when written by the optical writing process.

5. The medium of claim 2 , wherein the buffer layers have refractive indices that are matched to the refractive indices of the active data storage layers to allow the at least one data voxel to be writable by the optical writing process and readable by the optical reading device.

6. The medium of claim 2 , the at least one data voxel, comprising at least one of discrete bits, images, shapes, and/or holograms.

7. The medium of claim 2 , the active data storage layers having thicknesses less than the thicknesses of the buffer layers and the ratio of thicknesses of the active storage layers to the thicknesses of the buffers layers reducing cross-talk among active data storage layers, increasing signal-to-noise ratio, and reducing parasitic optical absorption and/or scattering.

8. The medium of claim 2 , the active data storage layers including a first thermoplastic polymer and the buffer layers including a second thermoplastic polymer, the first thermoplastic polymer and the second thermoplastic polymer having matching viscosities upon melting that allow the alternating active data storage layers and the buffer layers to be coextruded and form the multilayer film.

9. The medium of claim 2 , the active data storage layers including a host polymer material and a fluorescent dye and/or semiconductor nanoparticles, the fluorescence of the fluorescent dye and/or semiconductor nanoparticles being changed by the optical writing process to define the at least one data voxel within the discrete active data storage layer.

10. The medium of claim 9 , wherein the fluorescent dye and/or semiconductor nanoparticles undergo the permanent photothermally induced localized nonlinear or threshold change of fluorescence intensity when written by a single wavelength nonlinear or threshold optical writing process with excitation within a single-photon absorption band of the fluorescent dye and/or semiconductor nanoparticles.

11. The medium of claim 2 , wherein the active data storage layer has an absorption band that overlaps an emission spectrum of a laser used in the optical writing process.

12. The medium of claim 2 , further including at least one data voxel written below the diffraction limit and axially confined within a discrete active data storage layer of the active data storage layers by the optical writing process.

13. An optical information storage system comprising:
a multilayer polymeric film that includes a plurality of coextruded alternating polymeric active data storage layers and polymeric buffer layers, the active data storage layers configured to undergo a permanent photothermally induced localized nonlinear or threshold change of optical properties when written by a one photon or multi-photon optical writing process, the buffer layers separating the active data storage layers with sufficient thicknesses to axially confine at least one data voxel written by the optical writing process into a single discrete active data storage layer that is readable by an optical reading device, wherein the buffer layers have an average thickness of 3 μm to about 100 μm; and a laser for optical writing.

14. The system of claim 13 , the active data storage layers including a material that undergoes a change of reflectance and/or fluorescence when written by the optical writing process.

15. The system of claim 13 , the at least one data voxel, comprising at least one of discrete bits, images, shapes, and/or holograms.

16. The system of claim 13 , wherein the buffer layers have refractive indices that are matched to the refractive indices of the active data storage layers to allow the at least one data voxel to be writable by the optical writing process and readable by the optical reading device.

17. The system of claim 13 , the active data storage layers having thicknesses less than the thicknesses of the buffer layers and the ratio of thicknesses of the active storage layers to the thicknesses of the buffers layers reducing cross-talk among active data storage layers, increasing signal-to-noise ratio, and reducing parasitic optical absorption and/or scattering.

18. The system of claim 13 , the active data storage layers including a first thermoplastic polymer and the buffer layers including a second thermoplastic polymer, the first thermoplastic polymer and the second thermoplastic polymer having matching viscosities upon melting that allow the alternating data storage layers and the buffer layers to be coextruded and form the multilayer film.

19. The system of claim 13 , the active data storage layers including a host polymer material and a fluorescent dye and/or semiconductor nanoparticles, the fluorescence of the fluorescent dye and/or semiconductor nanoparticles being changed by the optical writing process to define the at least one data voxel within the discrete active data storage layer.

20. The system of claim 13 , further including at least one data voxel written below the diffraction limit and axially c

Assignees

• Univ Case Western Reserve

Inventors

• Singer Kenneth D
• Ryan Chris
• Shan Jie
• Lott Joseph
• Weder Christoph
• Valle Brent
• Baer Eric

Classifications

• G11B7/004 Primary

  Recording, reproducing or erasing methods; Read, write or erase circuits therefor {(magneto-optical systems G11B11/105)} · CPC title

• G11B7/0052

  involving reflectivity, absorption or colour changes · CPC title

• G11B7/242

  of recording layers · CPC title

• G11B7/26

  Apparatus or processes specially adapted for the manufacture of record carriers · CPC title

• G11B2007/0013

  for carriers having multiple discrete layers · CPC title