Method of recording/reproducing an information signal

• US 20010043545A1
• Filed: 03/29/2001
• Published: 11/22/2001
• Est. Priority Date: 08/08/1997
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Aratani, Katsushisa
• Granted Patent: US 6,356,524 B2
• Time in Patent Office: Days
• US Class Current: 369/95
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G11B 11/00 Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor driving or moving of heads G11B3/02, G11B5/48, G11B7/08, G11B21/02
• CPC Class Codes: G11B 21/02 Driving or moving of heads
• CPC Class Codes: G11B 23/0014 record carriers not specifically of filamentary or web form G11B23/0057 takes precedence
• CPC Class Codes: G11B 9/00 Recording or reproducing using a method not covered by one of the main groups G11B3/00 - G11B7/00; Record carriers therefor G11B11/00 takes precedence driving or moving of heads G11B21/02
• CPC Class Codes: G11B 9/04 using record carriers having variable electric resistance; Record carriers therefor
• CPC Class Codes: G11B 9/14 using microscopic probe means , i.e. recording or reproducing by means directly associated with the tip of a microscopic electrical probe as used in Scanning Tunneling Microscopy [STM] or Atomic Force Microscopy [AFM] for inducing physical or electrical perturbations in a recording medium; Record carriers or media specially adapted for such transducing of information marking using electrical current B41M5/20; measuring roughness or irregularity of surfaces G01B7/34; details of scanning-probe microscopes G01Q
• CPC Class Codes: G11B 9/1409 Heads
• CPC Class Codes: G11B 9/1418 Disposition or mounting of heads or record carriers G11B17/00 and G11B19/00 take precedence
• CPC Class Codes: G11B 9/1472 characterised by the form
• CPC Class Codes: Y10S 977/724 Devices having flexible or movable element
• CPC Class Codes: Y10S 977/86 Scanning probe structure
• CPC Class Codes: Y10S 977/861 Scanning tunneling probe
• CPC Class Codes: Y10S 977/869 Optical microscope
• CPC Class Codes: Y10S 977/935 Spin dependent tunnel, SDT, junction, e.g. tunneling magnetoresistance, TMR
• CPC Class Codes: Y10S 977/943 Information storage or retrieval using nanostructure
• CPC Class Codes: Y10S 977/947 with scanning probe instrument

Abstract

Disclosed is a method of recording/reproducing information signals at an access speed in the order of μs, a recording density of 1 to 10 GBs/cm², and a data transfer rate in the order of Gbit/sec without breakage of the data. The method includes the steps of: making a head device face to a memory medium having a flat recording surface, the head device including a plurality of head elements two-dimensionally arranged each of which has at its leading end a flat portion having an area of 0.1 μm² or less; moving the head device relative to the memory medium a distance more than a gap between two adjacent ones of the head elements; and recording an information signal at a specific position of the recording surface at a recording density of 1 Gbit/cm² or more, or reproducing an information signal previously recorded on the recording surface at a specific position by the head device.

Claims

1. A head element for recording or reproducing an information signal, comprising:

a flat portion formed at a leading end of said head element, wherein the area of said flat portion is 0.1 gm² or-less and is one-tenth or more of a recording cell size of a memory medium or the area of one bit.

3. A head element according to

claim 1

or

2

, wherein said leading end of said head element comprises a conductive member for recording or detecting an information signal and a non-conductive member adjacent to said conductive member, said non-conductive member being not allowed to record or detect an information signal.

4. A head device comprising:

a plurality of head elements described in any one of

claims 1

to

3

, which are two-dimensionally arranged on the surface of a substrate of said head device with a specific pitch.

5. A head device comprising:

a plurality of head elements described in any one of

claims 1

to

3

, which are arranged on a substrate of said head device at a density of 25 heads/cm² or more.

8. A head element and a head device according to any one of

claims 1

to

7

, wherein each of said head elements is driven a micro-distance in either or both of the X-axis direction and the Y-axis direction by an electrostatic force or piezoelectric effect.

11. A memory medium in which a recording surface on which an information signal is to be recorded is divided into information signal recording sectors of the same number as that of head elements of a head device for recording or reproducing an information signal described in any one of

claims 4

to

8

.

17. A method of recording/reproducing an information signal, comprising the steps of:

sectioning a recording surface of said memory medium described in

claim 11

into sectors; and

dividing an information signal of the same information signal series into parts and dispersedly recording the parts of the information signal on different ones of said sectors in the form of irregularities at a recording density of 1 Gbit/cm² or more.

23. An apparatus for recording/reproducing an information signal, comprising:

a memory medium including a flat information signal recording surface;

a head device arranged to be opposed to and in parallel to said information signal recording surface of said memory medium, said head device including a plurality of head elements described in

claim 1

two-dimensionally arranged with a specific pitch;

an applying device for applying an electric field, current, heat or pressure between said information signal recording surface of said memory medium and each of said head elements;

a driving device for moving said head device relative to said memory medium an extreme micro-distance; and

a recording/reproducing circuit for supplying an information signal to be recorded to each of said head elements of said head device or taking out the information signal recorded on said memory medium by each of said head elements.

24. An apparatus for recording/reproducing an information signal according to

claim 23

, wherein said applying device applies an electric field having a frequency higher than a mechanical primary resonance frequency of said driving portion between each of said head elements of said head device and the recording surface of said memory medium.

2. A head element for recording or reproducing an information signal, comprising:

a leading end portion formed into a columnar shape extending longer in the direction perpendicular to the surface of a substrate of said head element.

6. A head element or a head device according to any one of

claims 2

to

5

, wherein said substrate is a conductive substrate.

7. A head device comprising:

a plurality of head elements having mechanisms, said mechanisms allowing each of said head elements to be independently moved a specific distance in the direction perpendicular to a substrate of said head device.

9. A memory medium in which an address signal is formed of an information signal to be two-dimensionally recorded on a recording plane.

10. A memory medium in which an address signal is formed on a recording surface in the form of two-dimensional irregularities.

13. A memory medium according to any one of

claims 9

to

12

, wherein the substrate is made from a conductive material or is a non-conductive substrate on the surface of which a conductive thin layer is formed.

14. A memory medium according to

claim 13

, wherein the recording surface is covered with a conductive carbon thin film or a diamond-like carbon thin film.

12. A memory medium in which irregularities corresponding to an information signal are formed on the surface by injection-molding or extrusion-molding.

15. A memory medium comprising:

a substrate flattened without irregularities or partially formed with irregularities, the surface of which is covered with a thin film,

wherein said thin film is made from a material allowing an impedance between said memory medium and a head element to be locally changed before and after local application of an electric field, current, heat or pressure by said head element.

16. A method of recording/reproducing an information signal, comprising the steps of:

making a head device face to a memory medium having a flat recording surface, said head device including a plurality of head elements two-dimensionally arranged each of which has at its leading end a flat portion having an area of 0.1 μ

m² or less;

moving said head device relative to said memory medium a distance more than a gap between two adjacent ones of said head elements;

and recording an information signal at a specific position of said recording surface at a recording density of 1 Gbit/cm² or more, or reproducing an information signal previously recorded on said recording surface at a specific position by said head device.

18. A method of recording/reproducing an information signal according to

claim 16

or

17

, wherein an information signal is recorded on the recording surface of said memory medium in the form of irregularities or an information signal recorded on the recording surface of said memory medium in the form of irregularities is reproduced.

19. A method of recording/reproducing an information signal according to

claim 18

, wherein the information signal recorded on the recording surface in the form of irregularities is reproduced by applying an electric field between said head element and the recording surface of said memory medium, and detecting an impedance between said head element and said memory medium, said impedance being changed due to said irregularities corresponding to the information signal,

20. A method of recording/reproducing an information signal according to

claim 19

, wherein the information signal recorded on the recording surface in the form of irregularities is reproduced by detecting an impedance between said head element and the recording surface of said memory medium while bringing the leading end of said head element not in contact with the recesses of the irregularities but in contact with the projections of the irregularities.

21. A method of recording/reproducing an information signal according to any one of

claims 16

to

18

, wherein the information signal is reproduced by applying an electric field having a frequency higher than a mechanical primary resonance frequency of a driving portion of said head device between the leading end of said head element and the recording surface of said memory medium, and detecting a current modulated depending on the information signal.

22. A method of recording/reproducing an information signal according to any one of

claims 16

to

21

, wherein an information signal is recorded or reproduced by moving said head device relative to said memory medium in a state in which part of said head elements of said head device face to the recording surface of said memory medium.

25. A method of manufacturing a micro-head element, comprising:

a first step of forming a sacrifice layer made from a resist on a flat surface of a conductive substrate in such a manner that a central portion of said sacrifice layer is formed into a trapezoidal shape in cross section;

a second step of forming a metal film having a thickness of one to several μ

m over the entire surface of said conductive substrate in such a manner as to cover the surface of said sacrifice layer;

a third step of forming a symmetrical spring pattern on a central portion of said trapezoidal metal film;

a fourth step of forming a micro-resist film having one side less than the thickness of said metal film on a central portion of said spring pattern;

a fifth step of etching said metal film directly before said micro-resist film is perfectly separated from said metal film, to form a micro-head element including a leading end having a flat portion; and

a sixth step of removing said sacrifice layer and said micro-resist film, to form a spring, made from said metal film, for elastically supporting said micro-head element.

26. A method of manufacturing a micro-head element, comprising:

a first step of forming an insulating film having a specific thickness on the surface of a substrate which has a conductivity at least on the surface;

a second step of forming a mask on said insulating film at a specific position except for a portion equivalent to the cross-section of a columnar head element to be manufactured;

a third step of removing a portion of said insulating film equivalent to the cross section of said columnar head element; and

a fourth step of forming a metal layer in the portion from which said insulating film is removed by plating, to form said columnar head element.

27. A method of recording/reproducing an information signal, in which an information signal is reproduced from a flat memory medium on which information is two-dimensionally arranged and recorded, by moving a head element, arranged to be opposed to and in parallel to the information signal recording surface of said memory medium, relative to said memory medium, comprising the steps of:

two-dimensionally sampling a reproducing signal at an interval being a half or less of a pitch between signals two-dimensionally arranged on said memory medium;

temporarily storing a specific amount of the data in a buffer memory;

identifying, from said reproducing signal, an address signal as two-dimensional positional information stored on said memory medium; and

signal-processing a time at which the address signal is reproduced, a relative speed between said head element and said memory medium, a relative moving direction between said head element and said memory medium, and a data row stored in said buffer memory, thereby decoding the content of the data at a specific position on said memory medium.