Method and apparatus for optical data storage
View Patent ↗An optical disk ( 10 ) includes several tracks ( 21-23, 121-125 ) that each include a series of optical data elements ( 29, 39 ). Each optical data element includes several reflective surfaces ( 31-34, 41-44 ) with respective different orientations that represent stored information. A detection system ( 210 ) directs a beam from a laser ( 217 ) onto successive optical data elements. The multiple reflective surfaces of each optical data element produce multiple reflected sub-beams that are imaged onto respective portions of a detector ( 219, 501, 541 ). The position of each sub-beam on the corresponding portion of the detector is determined, to thereby identify the orientation of the corresponding reflective surface and thus the stored information represented by that surface.
1. An apparatus, comprising:
an information storage media having a plurality of reflective portions, each said reflective portion having a selected one of a plurality of predetermined orientations that are different, the number of said predetermined orientations being greater than two;
wherein said predetermined orientations are allocated among a predetermined number of groups so that each said predetermined orientation belongs to only one of said groups, each said group containing more than two of said predetermined orientations; and
wherein said information storage media includes a plurality of data elements which each include a plurality of said reflective portions equal in number to said predetermined number of groups, said reflective portions of each said data element having respective said orientations which each belong to a respective said group.
2. An apparatus according to claim 1 , wherein said information storage media includes a plurality of track sections extending approximately parallel to each other, each of said track sections having a plurality of said data elements arranged in succession therealong.
3. An apparatus according to claim 2 , wherein each said reflective portion is adjacent a further said reflective portion which is in the same said group, and which is in a different said data element disposed in the same said track section.
4. An apparatus according to claim 2 , wherein each said reflective portion is adjacent a further said reflective portion which is in the same said group, and which is in a different said data element disposed in an adjacent track section.
5. An apparatus according to claim 4 , wherein each said reflective portion is adjacent another said reflective portion which is in the same said group, and which is in a different said data element disposed in the same said track section.
6. An apparatus according to claim 1 , including:
a detector having a plurality of sections equal in number to the number of said reflective portions in each said data element, said sections of said detector each including a plurality of detector elements;
an optical system which can direct onto said media a beam of radiation that can illuminate one of said data elements so that each of the reflective portions of that data element produces a respective reflected beam, said optical system directing each of said reflected beams onto a respective said section of said detector; and
circuitry responsive to said detector elements of said detector for determining a position at which each of said reflected beams impinges on a respective said section of said detector to thereby determine the predetermined orientation of each said reflective portion of the data element illuminated by the beam.
7. An apparatus according to claim 6 , including structure for effecting relative movement of said media and said optical system.
8. An apparatus, comprising:
an information storage media having a plurality of reflective portions, each said reflective portion having a selected one of a plurality of predetermined orientations that are different, the number of said predetermined orientations being greater than two;
wherein each of said reflective portions is an approximately planar surface portion; and
wherein each of said predetermined orientations is defined by a first angle representing a tilt of the planar surface portion relative to a reference line and by a second angle representing a rotational orientation of the tilted planar surface portion about said reference line.
9. An apparatus according to claim 8 ,
wherein said planar surface portions each have in approximately the center thereof a reference point; and
wherein said reference points of all of said planar surface portions lie in a common plane.
10. An apparatus according to claim 9 , wherein said reference line for each said surface portion extends through said reference point for that surface portion.
11. An apparatus, comprising an information storage media having a plurality of reflective portions, each said reflective portion being configured to impart to radiation reflected therefrom a selected one of a plurality of predetermined characteristics that are different, said predetermined characteristics being allocated among a predetermined number of groups so that each said predetermined characteristic belongs to only one of said groups, and so that each said group contains more than two of said predetermined characteristics, said information storage media including a plurality of data elements which each include a plurality of said reflective portions equal in number to said predetermined number of groups, said reflective portions of each said data element having respective said predetermined characteristics which each belong to a respective said group.
12. An apparatus according to claim 11 , wherein said information storage media includes a track section having a plurality of said data elements arranged in succession therealong, each said reflective portion being adjacent a further said reflective portion which is in the same said group, and which is in a different said data element disposed in said track section.
13. An apparatus according to claim 11 , wherein said information storage media includes a plurality of adjacent track sections which each have a plurality of said data elements arranged in succession therealong, each said reflective portion being adjacent a further said reflective portion which is in the same said group, and which is in a different said data element disposed in an adjacent said track section.
14. An apparatus according to claim 13 , wherein each said reflective portion is adjacent another said reflective portion which is in the same said group, and which is in a different said data element disposed in the same said track section.
15. An apparatus according to claim 11 , wherein each said reflective portion has a selected one of a plurality of predetermined orientations that are different, each said predetermined characteristic corresponding to a respective said predetermined orientation and being a respective different angle of reflection for radiation.
16. An apparatus according to claim 11 , including:
a detector having a plurality of sections equal in number to the number of said reflective portions in each said data element;
an optical system which can direct onto said media a beam of radiation that can illuminate one of said data elements so that each of the reflective portions of that data element produces a respective reflected beam, said optical system directing each of said reflected beams onto a respective said section of said detector; and
circuitry responsive to said sections of said detector for determining said predetermined characteristic of each said reflective portion of the data element illuminated by the beam.
17. An apparatus according to claim 16 , including structure for effecting relative movement of said media and said optical system.
18. An apparatus, comprising:
an information storage media having a plurality of reflective portions, each said reflective portion being configured to impart to radiation reflected therefrom a selected one of a plurality of predetermined characteristics that are different, said information storage media including a plurality of data elements which each include a predetermined number of said reflective portions;
a detector having a plurality of sections equal in number to the number of said reflective portions in each said data element;
an optical system which can direct onto said media a beam of radiation that can illuminate one of said data elements so that each of the reflective portions of that data element produces a respective reflected beam, said optical system directing each of said reflected beams from the illuminated data element onto a respective said section of said detector; and
circuitry responsive to said sections of said detector for determining said predetermined characteristic of each said reflective portion of the data element illuminated by the beam.
19. An apparatus according to claim 18 , wherein each said section of said detector includes a plurality of detector elements arranged in a two-dimensional array, said circuitry determining said predetermined characteristics as a function of signals from each of said detector elements of each said section.
20. An apparatus according to claim 18 , wherein said data elements each have a size which is within a diffraction limited spot size of a focused beam of radiation having the same wavelength as said beam of radiation directed onto said media by said optical system.
21. An apparatus according to claim 18 ,
wherein said detector has four said sections which are arranged in a two dimensional array;
wherein each said section of said detector includes a first detector element which is L-shaped and has two legs disposed adjacent respective other said sections of said detector, and includes a plurality of second detector elements arranged in a two-dimensional array on an opposite side of said first detector element from other said sections of said detector; and
wherein when said circuitry is determining said predetermined characteristics said circuitry operates in an operational mode in which said circuitry ignores said first detector elements and is responsive to signals from each of said second detector elements of each said section of said detector.
22. An apparatus according to claim 21 , wherein said circuitry has a further operational mode in which signals from all of said detector elements for each said section are combined to produce a single signal for each said section of said detector.
23. An apparatus according to claim 18 , wherein said information storage media includes a plurality of track sections extending approximately parallel to each other, each of said track sections having a plurality of said data elements arranged in succession therealong.
24. A method, comprising the steps of:
providing an information storage media having a plurality of reflective portions;
configuring each said reflective portion to have a selected one of a plurality of predetermined orientations that are different, the number of said predetermined orientations being greater than two, and each said predetermined orientation representing respective different stored information;
allocating said predetermined orientations among a predetermined number of groups so that each said predetermined orientation belongs to only one of said groups, and each said group contains more than two of said predetermined orientations;
organizing said reflective portions as a plurality of data elements which each include a plurality of said reflective portions equal in number to said predetermined number of groups; and
configuring said reflective portions of each said data element to have respective said orientations which each belong to a respective said group.
25. A method according to claim 24 , including the steps of:
illuminating one of said data elements so that each of the reflective portions of that data element produces a respective reflected beam;
directing each of said reflected beams onto a detector having a plurality of sections equal in number to the number of said reflective portions in each said data element, in a manner so that each of said reflected beams is directed onto a respective said section of said detector; and
determining a position at which each of said reflected beams impinges on a respective said section of said detector to thereby determine the predetermined orientations of each of said reflective portions of the data element illuminated by the beam.
26. A method comprising the steps of:
providing an information storage media having a plurality of reflective portions;
configuring each said reflective portion to impart to radiation reflected therefrom a selected one of a plurality of predetermined characteristics that are different and that each represent different stored information;
allocating said predetermined characteristics among a predetermined number of groups so that each said predetermined characteristic belongs to only one of said groups, and so that each said group contains more than two of said predetermined characteristics;
organizing said reflective portions as a plurality of data elements which each include a plurality of said reflective portions equal in number to said predetermined number of groups; and
configuring said reflective portions of each said data element to have respective said predetermined characteristics which each belong to a respective said group.
27. A method according to claim 26 , including the step of selecting for each said reflective portion one of a plurality of predetermined orientations that are different, each said predetermined characteristic corresponding to a respective said predetermined orientation and being a respective different angle of reflection for radiation.
28. A method according to claim 26 , including the steps of:
directing a beam of radiation onto one of said data elements so that each of the reflective portions of that data element produces a respective reflected beam;
directing each of said reflected beams onto a detector having a plurality of sections equal in number to the number of said reflective portions in each said data element, in a manner so that each said reflected beam is directed onto a respective said section of said detector; and
determining said predetermined characteristic of each said reflective portion of the data element illuminated by the beam in response to outputs from said sections of said detector.
29. A method, comprising the steps of:
providing an information storage media having a plurality of reflective portions;
configuring each said reflective portion to impart to radiation reflected therefrom a selected one of a plurality of predetermined characteristics that are different;
organizing said reflective portions as a plurality of data elements which each include a predetermined number of said reflective portions;
directing a beam of radiation onto one of said data elements so that each of the reflective portions of that data element produces a respective reflected beam;
directing each of said reflected beams from the illuminated data element onto a detector having a plurality of sections equal in number to the number of said reflective portions in each said data element, in a manner so that each said reflected beam is directed onto a respective said section of said detector; and
determining said predetermined characteristic of each said reflective portion of the data element illuminated by the beam in response to outputs from said sections of said detector.
30. A method according to claim 29 ,
including the step of configuring said detector so that each said section thereof includes a plurality of detector elements arranged in a two-dimensional array; and
wherein said step of determining said predetermined characteristics is carried out as a function of signals from each of said detector elements of each said section.
31. An apparatus comprising an information storage media having a plurality of portions that each have a respective topography which is a selected one of a plurality of three-dimensional reflective topographies and which is responsive to radiation of a selected wavelength for producing a reflected beam that travels away from said media and that has a characteristic determined by the topography of that portion, each said characteristic being one of a plurality of predetermined states and the number of said predetermined states being greater than two.
32. An apparatus according to claim 31 ,
wherein said portions each have a dimension which is less than the selected wavelength; and
wherein adjacent said portions are positioned so that they are closer to each other than a distance equal to the selected wavelength.
33. An apparatus according to claim 31 , wherein a subset of said portions contains at least one said portion, is disposed within a region having an area less than approximately 2.56 μm 2 , and stores information corresponding to at least 17 bits.
34. An apparatus according to claim 33 , wherein said subset stores information corresponding to approximately 40 bits.
35. An apparatus according to claim 31 , wherein said number of said predetermined states is substantially greater than two.
36. An apparatus according to claim 35 , wherein said number of said predetermined states is approximately 885.
37. An apparatus according to claim 31 , wherein said characteristic is a direction of travel, and each of said states is a respective different direction of travel.
38. An apparatus according to claim 31 , including an optical system which can direct onto said media through a lens a beam of radiation having approximately said selected wavelength, said optical system being configured so that said lens is the last lens through which said beam of radiation passes before impinging on said media, and so that said reflected beam passes through said lens and said lens is the first lens through which said reflected beam passes after departing said media.
39. An apparatus comprising an information storage media having a plurality of information storage portions which are configured to have a beam of radiation with a selected wavelength impinge thereon, and which each include a plurality of reflective portions, said reflective portions each having a dimension which is less than the selected wavelength, and adjacent said reflective portions in each said information storage portion being positioned so that they are closer to each other than a distance equal to the selected wavelength.
40. An apparatus according to claim 39 , wherein each said information storage portion is disposed within a region having an area less than approximately 2.56 μm 2 , and stores information corresponding to at least 17 bits.
41. An apparatus according to claim 40 , wherein each said information storage portion stores information corresponding to approximately 40 bits.
42. An apparatus comprising an information storage media having a plurality of information storage portions which are reflective to radiation of a selected wavelength, said storage media storing information corresponding to at least 17 bits in at least one said information storage portion disposed within a region having an area less than approximately 2.56 μm 2 .
43. An apparatus according to claim 42 , wherein said information stored in said region corresponds to approximately 40 bits.
44. A method comprising:
providing an information storage media having a plurality of portions that each have a respective topography which is a selected one of a plurality of three-dimensional reflective topographies; and
configuring each said portion to be responsive to radiation of a selected wavelength for producing a reflected beam that travels away from said media and that has a characteristic determined by the topography of that portion, each said characteristic being one of a plurality of predetermined states and the number of said predetermined states being greater than two.
45. A method according to claim 44 , including:
configuring each of said portions to have a dimension which is less than the selected wavelength; and
positioning adjacent said portions so that they are closer to each other than a distance equal to the selected wavelength.
46. A method according to claim 44 , including:
selecting a subset of said portions which contains at least one said portion and which is disposed within a region having an area less than approximately 2.56 μm 2 ; and
storing information in said subset which corresponds to at least 17 bits.
47. A method according to claim 46 , wherein said storing is carried out so that said information stored in said subset corresponds to approximately 40 bits.
48. A method according to claim 44 , including selecting said number of said predetermined states to be substantially greater than two.
49. A method according to claim 48 , wherein said selecting of said number of said predetermined states is carried out so that said number of said predetermined states is approximately 885.
50. A method according to claim 44 , including selecting said characteristic to be a direction of travel, each of said states being a respective different direction of travel.
51. A method according to claim 44 ,
including providing an optical system which can direct onto said media through a lens a beam of radiation having approximately said selected wavelength; and
configuring said optical system so that said lens is the last lens through which said beam of radiation passes before impinging on said media, so that said reflected beam passes through said lens, and so that said lens is the first lens through which said reflected beam passes after departing said media.
52. A method comprising:
providing an information storage media having a plurality of information storage portions which are configured to have a beam of radiation with a selected wavelength impinge thereon, and which each include a plurality of reflective portions;
configuring each of said reflective portions to have a dimension which is less than the selected wavelength; and
positioning adjacent said reflective portions in each said information storage portion so that they are closer to each other than a distance equal to the selected wavelength.
53. A method according to claim 52 , including:
configuring each said information storage portion to be disposed within a region having an area less than approximately 2.56 μm 2 ; and
storing information in each said information storage portion which corresponds to at least 17 bits.
54. A method according to claim 53 , wherein said storing is carried out so that said information stored in each said information storage portion corresponds to approximately 40 bits.
55. A method comprising:
providing an information storage media having a plurality of information storage portions which are reflective to radiation of a selected wavelength; and
storing information corresponding to at least 17 bits in at least one said information storage portion disposed within a region having an area less than approximately 2.56 μm 2 .
56. A method according to claim 55 , wherein said storing is carried out so that said information stored in said at least one information storage portion corresponds to approximately 40 bits.