Method for parallel writing and reading of data in an optical memory, a writing/reading device for use by the method and uses of the method and the writing/reading device

• US 6,005,817 A
• Filed: 01/08/1998
• Issued: 12/21/1999
• Est. Priority Date: 07/18/1995
• Status: Expired due to Fees

• Current Assignee: Opticom ASA (Microsoft Corporation)
• Original Assignee: Opticom ASA (Microsoft Corporation)
• Inventors: Nordal, Per-Erik, Gudesen, Hans Gude
• Primary Examiner(s): Hoang, Huan
• Application Number:
  US08/981,661
• Time in Patent Office: 712 Days
• Field of Search: 365/215, 365/106, 365/234, 365/112
• US Class Current: 365/215
• CPC Class Codes: G11C 7/005 with combined beam-and individual cell access

Abstract

In a method for parallel writing and reading of data in an optical memory, the optical memory includes one or more microlenses for accessing a memory medium, individually addressable elements arranged in one or two-dimensional matrices in a write/read device are activated. The activation of an element physically influences one or more localized areas in a data carrying layer in the memory for writing and reading of data carrying structures in the localized area. Writing and reading is thus performed on the basis of a relationship between the geometric location of the element in the matrix and the position of the localized area(s) in the data carrying layer of the memory. A write/read device includes individually addressable elements which are arranged in one or two-dimensional matrices, the addressable element being arranged to be activated in order to physically influence one or more of the above-mentioned localized areas. Use for such a configuration includes, for example, writing and reading in optical memories which consist of 1-100 microlenses with associated data carrying layers and in optical memories which consist of a transparent spherical particle having a transparent layer to which is applied a data carrying film arranged on one side thereof.

Claims

1. A method for parallel writing and reading of data in an optical memory, comprising:

accessing an optical memory medium by the use of at least one of a plurality microlens, wherein the microlens has a uniquely defined (x, y) position in a coordinate reference assigned to the memory medium;

assigning, to the microlens, a plurality of data carrying spot positions in a data layer within the optical memory medium, wherein each spot position is assigned a data address corresponding to a set of incidence angles (θ

, φ

) of light that is directed through the microlens, the set of incidence angles (θ

, φ

) defining angular coordinates;

activating a matrix which is positioned freely in relation to the optical memory medium to access the angular coordinates of a data-carrying spot position under a microlens;

selecting an (x, y) position of the microlens relative to the coordinate reference on the optical memory medium,

wherein the steps of activating and selecting provide a complete four-coordinate address (θ

, φ

, x, y) for a data-carrying spot position, so that data is simultaneously written to or read from each of the available spot positions under each of the respective microlens.

2. A method according to claim 1, further comprising employing addressable electrodes in the matrix in order to induce a thermal effect in at least one of the data carrying spot positions in the data carrying layer.

3. A method according to claim 1, further comprising employing addressable electrodes which are in direct contact with the data carrying layer in the memory as addressable elements in the matrix.

4. A method according to claim 1, further comprising employing addressable optical detectors in the matrix.

5. A method according to claim 1, wherein said matrix is a two-dimensional array.

6. The method according to claim 1, wherein the step of activating a matrix further includes inducing at least one of an optical, thermal, electrical, magnetic and chemical effect in the data layer.

7. The method according to claim 1, wherein the step of assigning includes defining each angle of incidence as spherical coordinates in the coordinate system assigned to the memory medium.

8. The method according to claim 1, further comprising employing a plurality of light emitters in the matrix.

9. A method according to claim 8, further comprising employing an optically active element, common to all the light emitters of the matrix for directing light from each light emitter towards one of a microlens and a data carrying layer assigned to the microlens.

10. A method according to claim 8, further comprising employing optical elements assigned to each light emitter, for directing light from each light emitter towards one of a microlens and a data carrying layer assigned to the microlens.

11. A method according to claim 8, further comprising activating the light emitters simultaneously.

12. A method according to claim 8, further comprising activating the light emitters sequentially.

13. A method according to claim 8, further comprising activating the light emitters independently.

14. A method according to claim 8, further comprising arranging the light emitters in a surface which is located at a distance from a lens equal to the focal length of the lens, and positioning the light emitters in the surface in such a manner that light from each light emitter is collimated in a direction which is uniquely defined by the light emitter'"'"'s position in the surface.

15. A method according to claim 8, further comprising employing a spatial light modulator for selecting the individual microlens for accessing of the optical memory medium.

16. A method according to claim 8, further comprising covering the microlens with photo-sensitive film and using the photo-sensitive film for selecting the individual microlens for accessing of the optical memory medium.

17. A method according to claim 8, further comprising employing semiconductor lasers as light emitters.

18. A method according to claim 17, further comprising employing vertical cavity surface emitting lasers (VCSEL) as semiconductor lasers.

19. A method according to claim 8, further comprising directing at least one beam of light towards the microlenses and selecting the individual microlens for accessing of the optical memory medium in accordance with a level of absorption of the at least one light beam in a data carrying layer which is assigned to that microlens.

20. A method according to claim 19, said at least one light beam inducing a local thermal effect in the data carrying layer.

21. A method according to claim 19, said at least one light beam inducing at least one of a photo-electric and a photo-chemical sensitization of the data carrying layer with regard to light which is incident on and is focused by the microlens.

23. The use of the method according to claim 1 or the write/read device according to claim 22 for parallel writing and reading in an optical memory which comprises from 1 to 100 microlenses with an associated data carrying layer.

24. The use of the method according to one of the claim 1 or the write/read device according to claim 22 for parallel writing and reading in an optical memory consisting of a transparent spherical particle, on one side of which is provided a transparent layer which is applied to a data carrying film.

22. A write/read device for parallel writing and reading of data in an optical memory, comprising:

an optical memory medium;

at least one microlens for accessing the optical memory medium, wherein the microlens has a uniquely defined (x, y) position in a coordinate reference assigned to the memory medium;

a plurality of data carrying spot positions in a data layer within the optical memory medium, wherein the plurality of spot positions are assigned to the microlens, and wherein each spot position is assigned a data address corresponding to a set of incidence angles (θ

, φ

) of light that is directed through the microlens, the set of incidence angles (θ

, φ

) defining angular coordinates;

a matrix to access the angular coordinates of a data-carrying spot position under a microlens; and

a selector to select an (x, y) position of the microlens relative to a coordinate reference on the optical memory medium, wherein the matrix and selector provide a complete four-coordinate address (θ

, φ

, x, y) for a data-carrying spot position, so that data is simultaneously written to or read from each of the available spot positions under each of the respective microlens.

25. A write/read device according to claim 22, further comprising:

an electrical or optical spatial light modulator.

26. A write/read device according to claim 22, wherein said matrix is a two-dimensional array.

27. The write/read device according to claim 22, wherein each angle of incidence is defined as spherical coordinates in the coordinate system assigned to the memory medium.

28. The write/read device according to claim 22, wherein the matrix is part of a free-propagation addressing scheme which does not require a collimator.

29. The write/read device according to claim 22, wherein the matrix further includes a plurality of light emitters.

30. A write/read device according to claim 29, further comprising an optically active element which is common to all light emitters.

31. A write/read device according to claim 29, further comprising an optically active element for each of the light emitters.

32. A write/read device according to claim 29 further comprising a lens wherein the light emitting elements are arranged in a surface which is located at a distance from the lens equal to the focal length of the lens, and that the light emitting elements are so positioned in the surface that the light from a light emitter is collimated by the lens in a direction which is uniquely defined by the light emitter'"'"'s position in the surface.

33. A write/read device according to claim 29, wherein at least two of the addressable elements are optical detectors.

34. A write/read device according to claim 29, wherein the light emitters are semiconductor lasers.

35. A write/read device according to claim 34, wherein the semiconductor lasers are vertical cavity surface emitting lasers (VCSEL).

36. A write/read device according to claim 29, wherein matrix is arranged in or on the optical memory and integrated therewith.

37. A write/read device according to claim 36, wherein the matrix includes at least two addressable electrodes, the addressable electrodes inducing a thermal effect in at least one of the data carrying spot positions in the data carrying layer.

38. A write/read device according to claim 36, wherein the matrix includes at least two addressable electrodes which are in direct contact with the data carrying layer in the memory.

39. A method for parallel writing and reading of data in an optical memory, comprising:

accessing an optical memory medium by the use of at least one of a plurality microlens, wherein the microlens has a uniquely defined (x, y) position in a coordinate reference assigned to the memory medium;

assigning, to the microlens, a plurality of data carrying spot positions in a data layer within the optical memory medium, wherein each spot position is assigned a data address corresponding to a set of incidence angles (θ

, φ

) of light that is directed through the microlens, the set of incidence angles (θ

, φ

) defining angular coordinates;

activating a selected one of plural emitter elements of an emitter matrix to access, via an emitted accessing beam, the angular coordinates of a data-carrying spot position under each microlens, wherein said emitter matrix selects angular coordinates (θ

, φ

) for all uniquely defined (x, y) positions; and

selecting uniquely defined (x, y) positions of selected microlens relative to a coordinate reference on the optical memory medium, wherein the accessed angular coordinates (θ

, φ

) and the (x, y) provide a complete four-coordinate address (θ

, φ

, x, y) to enable parallel reading from and parallel writing to each of the available spot positions under each respective microlens.

40. The method according to claim 39, wherein the step of selecting uniquely defined (x, y) positions of selected microlens relative to a coordinate reference on the optical memory medium further comprises supplying supplemental light to supplement said accessing beam so as to enable parallel writing to each of the available spot positions under each respective microlens.

41. The method according to claim 39, wherein the step of assigning includes defining each angle of incidence as spherical coordinates in the coordinate system assigned to the memory medium.

42. The method according to claim 39, wherein the step of selecting uniquely defined (x, y) positions of selected microlens relative to a coordinate reference on the optical memory medium further comprises attenuating the accessing beam to prevent selection of unselected ones of said uniquely defined (x, y) positions.

43. The method according to claim 42, wherein the step of attenuating the accessing beam further comprises employing a spatial light modulator.

44. The method according to claim 39, wherein the step of activating a selected one of plural emitter elements of an emitter matrix to access the angular coordinates of a data-carrying spot position under a microlens is performed by activating a first emitter matrix, and wherein the step of selecting uniquely defined (x, y) positions of selected microlens relative to a coordinate reference on the optical memory medium is performed by activating a second emitter matrix.

45. The method according to claim 44, wherein the first emitter matrix accesses the angular coordinates independently from the second emitter matrix accessing the position of the microlens, and wherein the second emitter matrix is only activated for the writing of data simultaneously from each of the available spot positions under each respective microlens.

46. The method according to claim 44, wherein the steps of activating a first and second emitter matrix further includes inducing at least one of an optical, thermal, electrical, magnetic and chemical effect in the data layer.

47. The method according to claim 44, further comprising employing light emitters in at least one of the emitter matrices.

48. A write/read device for parallel writing and reading of data in an optical memory, comprising:

an optical memory medium;

at least one microlens for accessing the optical memory medium, wherein the microlens has a uniquely defined (x, y) position in a coordinate reference assigned to the memory medium;

a plurality of data carrying spot positions in a data layer within the optical memory medium, wherein the plurality of spot positions are assigned to the microlens, and wherein each spot position is assigned a data address corresponding to a set of incidence angles (θ

, φ

) of light that is directed through the microlens, the set of incidence angles (θ

, φ

) defining angular coordinates;

an emitter matrix accessing the angular coordinates (θ

, φ

) of a data-carrying spot position under each microlens by emitting an accessing beam, wherein said emitter matrix selects angular coordinates (θ

, φ

) for all uniquely defined (x, y) positions by supplying said accessing beam thereto; and

a selector selecting uniquely defined (x, y) positions of selected microlens, wherein the accessed angular coordinates (θ

, φ

) and (x, y) provide a complete four-coordinate address (θ

, φ

, x, y) to enable parallel reading from and parallel writing to each of the available spot positions under each respective microlens.

49. The write/read device according to claim 48, wherein the selector supplies supplemental light to supplement said accessing beam so as to enable parallel writing to desired spot positions under each respective microlens.

50. The write/read device according to claim 48, wherein each angle of incidence is defined as spherical coordinates in the coordinate system assigned to the memory medium.

51. The write/read device according to claim 48, wherein the emitter matrix is part of a free-propagation addressing scheme which does not require a collimator.

52. The write/read device according to claim 48, wherein the selector attenuates the accessing beam to prevent selection of unselected ones of said uniquely defined (x, y) positions.

53. The write/read device according to claim 52, wherein the selector is a spatial light modulator.

54. The write/read device according to claim 48, wherein the emitter matrix is a first emitter matrix, and wherein the selector is a second emitter matrix.

55. The write/read device according to claim 54, wherein the first emitter matrix accesses the angular coordinates independently from the second emitter matrix accessing the position of the microlens, and wherein the second emitter matrix is only activated for the writing of data simultaneously from each of the available spot positions under each respective microlens.

56. The write/read device according to claim 54, wherein at least one of the emitter matrices further includes light emitters.

58. The method according to claim 51, wherein the step of supplying a first light further comprises defining angular coordinates (θ

, φ

) for each of the uniquely defined positions underneath a microlens in the microlens-based memory medium.

57. A method for parallel writing of data in an optical memory, comprising:

(a) supplying a first light at less then a write threshold to a plurality of uniquely defined positions in a coordinate reference assigned to a microlens-based memory medium, wherein each position is assigned a first address corresponding to a first subset of said plurality of uniquely defined positions;

(b) supplying a second light at less than a write threshold to the microlens-based memory medium to provide a second address for each of the uniquely defined positions in the memory medium, wherein the second address corresponds to a second subset of said plurality of uniquely defined positions, each uniquely defined position being uniquely specified by the first and second address;

the first and second address being supplied by steps (a) and (b) being additive to exceed the write threshold and to uniquely address each of the uniquely defined positions; and

simultaneously writing logic data to those uniquely defined positions specified by a single first address in parallel by selectively supplying the second light to all uniquely defined positions specified by said first address to write a desired logic thereto.

59. The method according to claim 57, wherein the step of supplying a second light further comprises determining positional coordinates (x, y) to define the location of a microlens in the microlens-based memory medium, and wherein each microlens in the memory medium has a plurality of uniquely defined positions located underneath it.

60. A device for parallel writing of data in an optical memory, comprising:

a first light supplied at less then a write threshold to a plurality of uniquely defined positions in a coordinate reference assigned to a microlens-based memory medium, wherein each position is assigned a first address corresponding to a first subset of said plurality of uniquely defined positions;

a second light supplied at less than a write threshold to the microlens-based memory medium to provide a second address for each of the uniquely defined positions in the memory medium, wherein the second address corresponds to a second subset of said plurality of uniquely defined positions, each uniquely defined position being uniquely specified by the first and second address, and

wherein the first light and second light are additive to exceed the write threshold to uniquely address each of the uniquely defined positions, and to simultaneously write logic data to those uniquely defined positions specified by a single first address in parallel by selectively supplying the second light to all uniquely defined positions specified by said first address, thereby writing a desired logic thereto.

61. The device according to claim 60, wherein the first subset comprises angular coordinates (θ

, φ

) associated with each of the uniquely defined positions underneath a microlens in the microlens-based memory medium.

62. The device according to claim 60, wherein the second subset comprises positional coordinates (x, y) associated with a location of a microlens in the microlens-based memory medium, wherein each microlens in the memory medium has a plurality of uniquely defined positions located underneath it.