JP2006185492A - Optical memory device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an optical memory having large capacity even though the optical memory is miniaturized by effectively utilizing a near field light recording technology realizing high density recording. <P>SOLUTION: An optical memory device which is miniaturized and has large capacity can be realized since recording and reproduction of large capacity can be performed even when a rotational radius is made small by recording with irradiation of near field light and detecting returned light by using a cylindrical recording medium 101. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical memory device, and more particularly to an optical memory device capable of recording or reproducing information on a cylindrical recording medium, or both information recording and reproduction operations.

In optical memories such as CDs (compact discs) and DVDs (digital video discs) that are currently in practical use, laser light is collected using an objective lens and irradiated onto a minute area of the recording medium, and reflected from this minute area. Information is reproduced by detecting light. For recording media capable of recording information such as DVD-R and DVD-RW, information is recorded by heating the recording layer with condensed light and acting on the recording layer material. ing.
In the above method, the recording density can be improved by reducing the size of the focused spot by the objective lens. However, the size of the focused spot is limited by the diffraction limit of light. It cannot be formed. At this stage, a blue-violet laser (wavelength 405 nm) is used as a light source. A. It is considered difficult to exceed a system that forms a spot having a diameter of about 400 nm using an objective lens having a numerical aperture of 0.85.

On the other hand, what is called a near-field optical memory has been proposed as an optical memory system that exceeds the diffraction limit (see, for example, Patent Documents 1, 2, and 3).
The basic concept of the near-field optical memory device will be described using FIG. 27 as an example.
FIG. 27 is an explanatory diagram of a basic concept of a near-field optical memory device as a conventional example of an optical memory device.
A fiber probe 2701 having a sharp aperture (for example, a circular aperture with a diameter of 100 nm) formed on a disk-shaped recording medium 2700 that rotates is arranged close to a distance of several tens of nm. When laser light from a semiconductor laser 2703 as a light source propagates through the objective lens 2702 and reaches the minute aperture, near-field light localized in a region below the diffraction limit near the minute aperture is generated. When the recording medium is a metal film deposited on the glass surface and in which minute pits (holes) having a wavelength or less according to the recording information are arranged, the near-field light generated by the fiber probe 2701 is recorded on the recording medium. The light is scattered and transmitted through a minute aperture 2700, and a part thereof is detected by a photodiode 2705 which is a photodetector through a lens 2704. Therefore, the recorded information on the recording field 2700 is reproduced by monitoring the change in light intensity transmitted from the rotating recording medium 2700 with the photodiode 2705.
JP 2000-21005 A JP 2000-182271 A JP 2001-52363 A

As described above, it is possible to improve the recording density by using near-field light. However, as with conventional optical discs (CD, DVD, etc.), the recording medium becomes smaller when the device is miniaturized. As a result, the recordable area decreases, and as a result, the entire recording capacity decreases. In particular, in a disk-shaped recording medium, since the area near the center of the disk is used as an area for connecting to a motor, information cannot be recorded in this area, and therefore recording can be performed by reducing the diameter of the disk. Area is extremely reduced.
SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem and to realize a small-sized and large-capacity optical memory by effectively functioning a near-field optical recording technique for realizing high-density recording.

  In order to solve the above-mentioned problems, a first aspect of the present invention is directed to a cylindrical recording medium having a recording film whose optical characteristics change in response to energy of an electromagnetic field, and a near field of energy that changes the optical characteristics. Recording means for recording information on the recording medium by irradiating light, and reproduction for reading the recorded information by return light when irradiated with near-field light having an energy that does not change the optical characteristics Means.

  According to a second aspect of the present invention, there is provided a cylindrical recording medium having a recording film whose optical characteristics change in response to energy of an electromagnetic field, and irradiating near-field light having an energy enough to change the optical characteristics. It is characterized by comprising recording means for recording information on a recording medium, and reproducing means for detecting propagation light transmitted and scattered in the recording film and reading the recorded information.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein at least a part of the recording means and the reproducing means is provided in a space inside the recording medium having the cylindrical shape. It is characterized by.

  The invention according to claim 4 is the invention according to claim 3, wherein the output shaft for rotating the recording medium is hollow and the motor is coaxial with the recording medium, and the output shaft of the motor And transmitting means for allowing light to pass between the inner peripheral surface of the cylindrical recording medium and between the space and the outside of the output shaft.

  According to a fifth aspect of the invention, in the first aspect of the invention, the recording medium has a configuration in which at least a recording film of a recording film and a dielectric film is laminated on a cylindrical substrate using a metal material. It is characterized by that.

  According to a sixth aspect of the present invention, in the first or second aspect of the present invention, the recording medium is characterized in that a protective film is provided on an inner peripheral surface or an outer peripheral surface of a cylinder.

  The invention according to claim 7 is the invention according to claim 1 or 2, wherein the recording means or the reproducing means is formed on a transparent substrate and uses a metal material for generating or scattering near-field light. A structure is provided.

  The invention according to claim 8 is the invention according to claim 1 or 2, characterized in that the recording means or the reproducing means has a configuration of a slider that floats or slides with respect to the surface of the recording medium. To do.

  The invention according to claim 9 is used in the invention according to claim 1 or 2 by being mounted on the recording medium when the recording medium is separated from a reproducing apparatus main body provided with the near-field optical head. A protective cap is provided.

(Claim 1)
Recording and playback of large volumes can be performed even with a small radius of rotation by irradiating near-field light using a cylindrical recording medium and detecting return light. The optical memory device is realized.

(Claim 2)
By using a cylindrical recording medium for recording and playback using transmission and scattering of near-field light, large capacity recording and playback can be performed even with a small radius of rotation. The optical memory device is realized.

(Claim 3)
Since at least a part of the recording means and the reproducing means is provided in the space inside the recording medium having a cylindrical shape, the size of the entire apparatus can be further reduced, so that a compact optical memory device is realized. Is done.

(Claim 4)
Since the motor, the recording medium, and the near-field optical pickup can be efficiently arranged, a further compact optical memory device is realized.

(Claim 5)
Since there is no need to separately provide a reflective film, a recording medium can be realized easily and at a low price.

(Claim 6)
Even when an impact is applied to the recording medium for some reason, the reliability of the apparatus can be ensured by protecting the recording medium from these risk factors.

(Claim 7)
Near-field light is generated in a smaller area than the configuration using the fiber probe to realize higher density recording and at the same time to realize a small apparatus.

(Claim 8)
Since the distance between the recording medium and the fiber probe or the near-field optical probe can be kept constant using a simple and inexpensive configuration, stable and high-quality recording / reproduction can be performed.

(Claim 9)
By taking dust-proof measures, even if the recording medium is stored or carried separately from the recording / reproducing device body, recording and reproduction can be performed without any trouble in the subsequent recording and reproduction, ensuring the reliability of the device. it can.

The optical memory device of this embodiment includes a cylindrical recording medium having a recording film whose optical characteristics change in response to the energy of an electromagnetic field, and a recording medium by irradiating near-field light with energy that changes the optical characteristics. And a recording means for recording information, and a reproducing means for reading the recorded information by return light when irradiated with near-field light having an energy that does not change the optical characteristics.
The optical memory device of this embodiment includes a cylindrical recording medium having a recording film whose optical characteristics change in response to the energy of an electromagnetic field, and a recording medium by irradiating near-field light with energy that changes the optical characteristics. And a recording means for recording information and a reproducing means for detecting the propagation light transmitted and scattered in the recording film and reading the recorded information.

  In the optical memory device of the present embodiment, in addition to the above configuration, at least a part of the recording unit and the reproducing unit may be provided in a space inside the recording medium having a cylindrical shape, in order to rotate the recording medium. The output shaft of the motor is hollow and coaxial with the recording medium, and is provided in the space of the output shaft of the motor. Light is transmitted between the inner peripheral surface of the cylindrical recording medium and the space and the outside of the output shaft. And a transmission means for allowing the light to pass therethrough.

In addition to the above configuration, the optical memory device according to the present embodiment may have a configuration in which at least the recording film of the recording film and the dielectric film is stacked on a cylindrical substrate using a metal material. The recording medium may be provided with a protective film on the inner or outer peripheral surface of the cylinder, and the recording means or reproducing means is formed on a substrate using a transparent member to generate or scatter near-field light. You may provide the structure using the metal material for making it.
Furthermore, in addition to the above-described configuration, the optical memory device of the present embodiment may include a slider that floats or slides with respect to the surface of the recording medium. A protective cap that is used by being attached to a recording medium may be provided in the case of being stored or carried separately from the provided reproducing apparatus main body.

Embodiments of the present invention will be specifically described below with reference to the drawings.
[Example 1]
FIG. 1 is a conceptual diagram showing an embodiment of an optical memory device according to the present invention.
The basic configuration of this embodiment is a cylindrical recording medium 101, a motor 100 for supporting the recording medium 101 at one end and rotating the recording medium 101, and recording information on the recording medium 101. A near-field optical pickup 109 in which a recording means and a reproducing means for reproducing recorded information are integrated is arranged as shown in FIG.
2 is a cross-sectional view of the recording medium used in the optical memory device shown in FIG. 1 taken along the line II-II.
As shown in FIG. 2, the recording medium 101 includes a reflective film (gold, silver, aluminum, etc.) 201 and a dielectric film (ZnS and SiO) on the outer peripheral surface of a substrate 200 having a cylindrical shape formed of glass or resin. film, etc.) 202a with a mixed material _2, the phase change layer (AgInSbTe or GaAgInSbTe, GeSbTe or the like) 203, and a dielectric film (with a mixed material of ZnS and SiO ₂ film, etc.) 202b was sequentially depositing a film structure have.
Further, the motor 100 and the recording medium 101 shown in FIG. 1 are detachable, and the recording / reproducing apparatus main body (such as the motor 100 and the near-field optical pickup 109 is recorded by moving the recording medium 101 in the direction of the arrow 110. 101 can be carried separately from the components necessary for recording and reproduction.

Here, as shown in FIG. 1, the near-field light pickup 109 includes a semiconductor laser 108 that is a light source, a fiber probe 102 that plays a role of generating near-field light and converting near-field light into propagating light again, A beam splitter 104 for branching the optical path, a photodetector (photodiode) 107 for detecting the light intensity modulated by the recording information, and a lens group (objective lens) for optically and efficiently connecting the elements 103, a collimating lens 105, and a lens 106).
There is no particular limitation on the wavelength of the semiconductor laser 108. For example, a semiconductor laser that emits light at a signal wavelength used in general optical equipment such as 780 nm, 680 nm, and 405 nm can be used.

FIG. 3 is a longitudinal sectional view of a fiber probe used in the optical memory device shown in FIG.
As shown in FIG. 3, the tip of the fiber probe 102 is coated with a metal material (for example, gold, silver, aluminum, etc.) around the core 302 sharpened in a truncated cone shape to form a metal coating layer 300, A micro opening (for example, an opening having a diameter of about 50 nm) 303 is formed at the tip (left end in the figure), and light that reaches the tip through the inside of the fiber probe 102 is near the micro opening 303. Near-field light is generated. Reference numeral 301 denotes a clad having a refractive index lower than that of the core 302 and covering the core 302.

4A is an external perspective view of the recording medium used in the optical memory device shown in FIG. 1, and FIG. 4B is a partially enlarged view of the outer peripheral surface of the recording medium shown in FIG. .
The diameter of the minute opening 303 at the tip of the fiber probe shown in FIG. 3 is formed to be smaller than the track pitch P in FIG. The metal coating layer 300 shown in FIG. 3 is formed with a thickness such that the light inside (core 302) does not leak to the outside, for example, about 50 to 300 nm.
The entire near-field optical pickup 109 is integrated as one unit, and is moved by a drive system (not shown) with respect to a direction parallel to the central axis of the cylindrical recording medium 101 (in the direction of arrow 110 in FIG. 1). It is configured to be able to. During movement, the tip of the fiber probe 102 and the surface of the recording medium 101 are kept at a certain distance below the wavelength of the light source (semiconductor laser 108).
On the other hand, as shown in FIG. 1, the recording medium 101 is connected to a motor 100 and is configured to rotate at a constant rotational speed. The horizontal movement between the rotational movement mechanism and the near-field light pickup 109 is horizontal. By the moving mechanism, the recording information at all positions on the recording medium 101 can be accessed.

Information is recorded on the recording medium 101 rotated around the central axis (vertical axis in the figure) of the recording medium 101 shown in FIG. 1 in the form of pulsed near-field light modulated according to the information to be recorded (however, , Having an energy sufficient to change the optical characteristics).
Here, the temporally modulated pulse-like near-field light is generated by converting the light whose intensity is modulated by the semiconductor laser 108 into the near-field light by the fiber probe 102. Continuous data on the recording medium 101 formed by this operation is arranged in a spiral pattern on the surface (outer peripheral surface) of the cylindrical recording medium 101 shown in FIG.

  In FIG. 4B, the recording marks 401 arranged in the vertical direction represent a continuous data row (data track). When the cylindrical recording medium 101 makes one round in the circumferential direction, the adjacent recording marks 401 are arranged. Connected. Specific examples of dimensions of the distance (track pitch) P between the recording mark 401 and the data track include, for example, a diameter of the recording mark 401 of 50 to 100 nm and a track pitch P of about twice the diameter of the recording mark 401. .

In reproducing (reading) the recorded information, first, the recording medium 101 shown in FIG. 1 is rotated around the central axis of the recording medium 101, and the tip of the fiber probe 102 has a recording mark 401 (FIG. b) Reference) The near-field light pickup 109 is arranged so as to be positioned above. In this state, the semiconductor laser 108 is continuously turned on to generate near-field light between the tip of the fiber probe 102 and the recording medium 101, and according to the arrangement of the recording marks 401 (see FIG. 4B), the time is increased. The photodiode 107 detects the intensity of the return light (light propagating from the minute opening 303 at the tip of the fiber probe 102 (see FIG. 3) to the beam splitter 104 side) in the fiber probe 102 that is modulated by the photodiode 107.
By such an operation, a signal corresponding to the recorded information is detected. The track being read moves in the direction of one of the adjacent tracks in conjunction with the rotational movement of the recording medium 101, and the near-field optical pickup 109 moves in conjunction with this movement. . By this interlocking, continuous data arranged on the outer peripheral surface of the recording medium 101 is read out.

[Example 2]
FIG. 5 is a conceptual diagram showing another embodiment of the optical memory device according to the present invention. 6 is a cross-sectional view taken along line VI-VI in FIG. FIG. 7 is a sectional view taken along line VII-VII of the recording medium used in the optical memory device shown in FIG. 8A is an external perspective view of the recording medium used in the optical memory device shown in FIG. 5, and FIG. 8B is a partially enlarged view of the inner peripheral surface of the recording medium shown in FIG. is there.
The basic configuration of this embodiment is a cylindrical recording medium 500 shown in FIG. 5, a roller 508 that supports the recording medium 500 on its side, rollers 600 and 601 (see FIG. 6), and a recording medium via the roller 508. A near-field optical pickup in which a motor 509 for rotating 500, a recording unit for recording information on the recording medium 500, and a reproducing unit for reproducing recorded information are integrated. 511 is arranged as shown in FIGS. 5 and 6.
As shown in FIG. 7, the recording medium 500 includes a reflective film (gold, silver, aluminum, etc.) 702 and a dielectric film (ZnS and SiO ₂ ) on the inner surface of a cylindrical substrate 703 formed of glass or resin. 700a, a phase change film (AgInSbTe, GaAgInSbTe, GeSbTe, etc.) 701, and a dielectric film (such as a film made of a mixed material of ZnS and SiO ₂ ) 702b. ing.
Further, the recording medium 500 is recorded and reproduced by moving the rollers 600 and 601 shown in FIG. 6 upward (in the direction of arrow 604) in FIG. 6 and moving the recording medium 500 in the direction of arrow 510 shown in FIG. It can be carried separately from the apparatus main body (components necessary for recording and reproduction on the recording medium 500 such as the motor 508 and the near-field optical pickup 511).

As shown in FIG. 5, the near-field optical pickup 511 includes a semiconductor laser 505 that is a light source, a fiber probe 501 that plays a role of generating near-field light and converting near-field light into propagating light again, and for optical path branching. The beam splitter 503, a photodetector (photodiode) 507 for detecting the light intensity modulated by the recording information, and a lens group (objective lens 502, collimator) for optically and efficiently connecting the elements. A lens 504 and a lens 506).
There is no particular limitation on the wavelength of the semiconductor laser 505. For example, a semiconductor laser that emits light at a signal wavelength used in general optical equipment such as 780 nm, 660 nm, and 405 nm can be used.
As shown in FIG. 3, the tip of the fiber probe 501 is coated with a metal material (for example, gold, silver, aluminum, etc.) around the core 302 sharpened in a truncated cone shape to form a metal coating layer 300. A micro opening (for example, an opening having a diameter of about 50 nm) 303 is formed at the tip, and is bent substantially perpendicularly to the longitudinal direction of the fiber probe 501 and guided inside the fiber probe 501. Then, the light that reaches the tip generates near-field light in the vicinity of the minute opening 303. The diameter of the minute opening 303 is formed to be smaller than the track pitch P shown in FIG.
The metal coating layer 300 is formed with a thickness that prevents light inside the core 302 from leaking to the outside, for example, a thickness of about 50 to 300 nm. The entire near-field optical pickup 511 is integrated as one unit, and is moved by a drive system (not shown) in a direction parallel to the central axis of the cylindrical recording medium 500 (in the direction of arrow 510 in FIG. 5). It is configured to be able to. During this movement, a constant distance not more than the wavelength of the light source (semiconductor laser 505) is maintained between the tip of the fiber probe 501 and the inner peripheral surface of the recording medium 500.

On the other hand, as shown in FIG. 5, the recording medium 500 is connected to a motor 509 via a roller 508 and is configured to rotate at a constant rotation speed. The recording information of all positions on the recording medium 500 can be accessed by the horizontal movement mechanism of the pickup 511.
Information recording is performed by irradiating the rotated recording medium 500 with pulsed near-field light modulated according to the information to be recorded.

  Here, the temporally modulated pulse-like near-field light is generated by converting light intensity-modulated by the semiconductor laser 505 into near-field light by the fiber probe 501. The continuous data on the recording medium 500 formed by this operation is arranged so as to draw a spiral on the cylindrical surface (inner peripheral surface) as shown in FIG. In FIG. 8B, the recording marks 801 arranged in the vertical direction represent a continuous data row (data track). When the cylindrical recording medium 500 makes one round in the circumferential direction, the recording marks 801 are arranged adjacent to each other. Connected. Specific examples of dimensions of the distance between the recording mark 801 and the data track (track pitch P) include, for example, a recording mark 801 having a diameter of 50 to 100 nm and a track pitch P of about twice the diameter of the recording mark 801. .

  For reproducing (reading) the recorded information, first, the recording medium 500 is rotated, and the near-field optical pickup is positioned so that the tip of the fiber probe 501 is positioned on the recording mark 801 (see FIG. 8B) having information to be read. Arrange. In this state, the semiconductor laser 505 is continuously turned on to generate near-field light between the tip of the fiber probe 501 and the recording medium 500, and temporally modulated according to the arrangement of the recording marks 801 (see FIG. 8B). The intensity of the return light (light propagating from the minute opening 303 at the tip of the fiber probe 501 (see FIG. 3) to the beam splitter 503 side) in the fiber probe 501 is detected by the photodiode 507. Thereby, a signal corresponding to the recording information is detected. The track being read moves in the direction of one of the adjacent tracks in conjunction with the rotational movement of the recording medium 500, and the near-field optical pickup 511 moves in conjunction with this movement. . By this interlocking, continuous data arranged in the form of a recording medium is read out.

(Example 3)
FIG. 9 is a conceptual diagram showing another embodiment of the optical memory device according to the present invention.
The basic configuration of this embodiment is based on a cylindrical recording medium 900, a motor 901 for supporting the recording medium 900 at one end (right side in the figure) and rotating the recording medium 900, and the recording medium 900. A recording means for recording information and a near-field optical pickup 912 in which a reproducing means for reproducing recorded information is integrated are arranged as shown in FIG.
As shown in FIG. 7, a recording medium 900 has a reflective film (gold, silver, aluminum, etc.) 701 and a dielectric film (ZnS) formed on the inner peripheral surface of a substrate 700 having a cylindrical shape formed of glass or resin. and such film with a mixed material of SiO ₂₎ 702a, a phase change film (AgInSbTe or is GaAgInSbTe, GeSbTe or the like) 703, and the dielectric film (with a mixed material of ZnS and SiO ₂ film) depositing a film in the order of 702b It is the composition made to do.
The cylindrical recording medium 900 has one end (right side in the figure) attached to the disk-like convex portion of the motor 901 with the inner peripheral surface of the opening, and the other end (left side in this case) is shown in FIG. As shown in Fig. 1, it is closed for dust prevention. FIG. 10 is an external perspective view showing a state in which the cap 1000 is put on the recording medium shown in FIG.
In addition, the recording medium 900 moves in the direction of the arrow 911 shown in FIG. ) And can be carried separately.

As shown in FIG. 10, the recording medium 900 separated from the recording / reproducing apparatus main body is configured to be carried by attaching a cap 1000 to prevent dust from entering from an opening at one end.
As shown in FIG. 9, the near-field optical pickup 912 includes a semiconductor laser 910 that is a light source, a fiber probe 902 that plays a role of generating near-field light and converting near-field light into propagating light again, and an optical path branch Beam splitter 905, a photodetector (photodiode) 910 for detecting the light intensity modulated by the recorded information, and a lens group (objective lens 904, optically efficient connection between the elements) A configuration including a collimating lens 906 and a lens 908).
The wavelength of the semiconductor laser 910 is not particularly limited. For example, a semiconductor laser that emits light with a signal wavelength used in general optical equipment such as 780 nm, 660 nm, and 405 nm can be used.
As shown in FIG. 9, the fiber probe 902 is attached with a support (for example, a metal pipe) 903 for increasing rigidity, and a transmission hole 907 as a transmission means provided in the longitudinal direction at the center of the output shaft of the motor 901. Has been inserted. The fiber probe 902 is bent near the tip in a direction perpendicular to the longitudinal direction of the fiber probe 902. As shown in FIG. 3, the tip of the fiber probe 902 is metal around the core 302 sharpened in a truncated cone shape. The coating layer 300 is formed by coating with a material (for example, gold, silver, aluminum, etc.), and a minute opening (for example, an opening having a diameter of about 50 nm) 303 is formed at the tip. Light that has guided through the interior and reached the tip generates near-field light in the vicinity of the minute aperture 303. The diameter of the minute opening 303 is formed to be smaller than the track pitch P shown in FIG.
The metal coating layer 300 is formed with a thickness that prevents light inside the core 302 (see FIG. 3) from leaking to the outside, for example, a thickness of about 50 to 300 nm. The entire near-field optical pickup 912 is integrated as a unit including the fiber probe 902, and is illustrated with respect to a direction parallel to the central axis of the cylindrical recording medium 900 (the direction of the arrow 911 in FIG. 9). It can be moved by a drive system that does not. During this movement, a constant distance equal to or less than the wavelength of the light source (semiconductor laser 910) is maintained between the tip of the fiber probe 902 and the inner peripheral surface of the recording medium 900.

On the other hand, the recording medium 900 is connected to a motor 901 and is configured to rotate at a constant rotational speed. The recording medium 900 is arranged on the recording medium 900 by the rotating mechanism and the horizontal movement mechanism of the near-field optical pickup 912 described above. The recording information at all the positions in can be accessed.
Other configurations and recording / reproducing operations are the same as those in the second embodiment.

Example 4
FIG. 11 is a sectional view showing another embodiment of a recording medium used in the optical memory device according to the present invention.
In the present embodiment, the configuration of the recording medium 101 in the first embodiment (see FIG. 2) is configured as shown in FIG.
As shown in FIG. 11, this recording medium 1100 has a dielectric film (such as a film made of a mixed material of ZnS and SiO ₂ ) on the outer peripheral surface of a cylindrical substrate 1101 formed of a metal material (such as aluminum). 1103a, a phase change film (AgInSbTe, GaAgInSbTe, GeSbTe, etc.) 1102, and a dielectric film (a film made of a mixed material of ZnS and SiO ₂ ) 1103b are sequentially deposited. Other configurations and recording / reproducing operations are the same as those in the first embodiment.

(Example 5)
FIG. 12 is a sectional view showing another embodiment of a recording medium used in the optical memory device according to the present invention.
In the present example, the configuration of the recording medium in Examples 2 and 3 (see FIG. 7) is configured as shown in FIG.
This recording medium 1200 has a dielectric film (such as a film made of a mixed material of ZnS and SiO ₂ ) 1202 a and a phase change film (such as a film made of a mixed material of ZnS and SiO ₂ ) on the inner peripheral surface of a cylindrical substrate 1201 formed of a metal material (such as aluminum). AgInSbTe, GaAgInSbTe, GeSbTe, etc.) 1203 and a dielectric film (such as a film made of a mixed material of ZnS and SiO ₂ ) 1202b are deposited in this order. Other configurations and recording / reproducing operations are the same as those in the first and second embodiments.

(Example 6)
FIG. 13 is a conceptual diagram showing another embodiment of the optical memory device according to the present invention. 14 is a cross-sectional view taken along line XIV-XIV in FIG.
The basic configuration of the present embodiment is a cylindrical recording medium 1300, a motor 1301 for supporting the recording medium 1300 at one end and rotating the recording medium 1300, and recording information on the recording medium 1300. A near-field optical pickup 1304 in which recording means for performing and reproducing means for reproducing recorded information are integrated.
As shown in FIG. 2, the recording medium 1300 has a dielectric film (such as a film made of a mixed material of ZnS and SiO ₂ ) and a phase change on the outer peripheral surface of a transparent substrate having a cylindrical shape formed of glass or resin. The film is deposited in the order of a film (AgInSbTe, GaAgInSbTe, GeSbTe, etc.) and a dielectric film (a film made of a mixed material of ZnS and SiO ₂ ). The recording medium 1300 and the motor 1301 are detachable, and the recording / reproducing apparatus main body (such as the motor 1301 and the near-field optical pickup 1401 is moved by moving the recording medium 1300 in the direction of the arrow 1305 shown in FIG. It is possible to carry the recording medium 1300 separately from components necessary for recording and reproduction.

As shown in FIG. 14, the near-field light pickup 1401 is disposed in a space inside the recording medium 1300 and a near-field light irradiation unit 1304 for irradiating the recording medium 1300 with the near-field light. It is comprised from two parts with the photodetector (photodiode) 1400 for detecting the propagation light which permeate | transmitted. The near-field light irradiation unit 1304 includes a semiconductor laser 1303 as a light source, a fiber probe 1310 that generates near-field light, and a lens 1302 for optically connecting the semiconductor laser 1303 and the fiber probe 1310 as a light source. Composed.

There is no particular limitation on the wavelength of the semiconductor laser 1303, and for example, a semiconductor laser that emits light at a signal wavelength used in general optical equipment such as 780 nm, 660 nm, and 405 nm can be used.
As shown in FIG. 3, the tip of the fiber probe 1310 is coated with a metal material (eg, gold, silver, aluminum, etc.) around the core 302 sharpened in a truncated cone shape to form a metal coating layer 300. In this configuration, a minute opening (for example, an opening having a diameter of about 50 nm) 303 is formed at the tip, and light reaching the tip after being guided through the inside of the fiber probe 1310 is subjected to near-field light in the vicinity of the minute opening 303. It is supposed to occur.
The diameter of the minute opening 303 is formed to be smaller than the track pitch P shown in FIG. The metal coating layer 300 is formed with a thickness that prevents light inside the core 302 from leaking to the outside, for example, a thickness of about 50 to 300 nm. The entire near-field optical pickup 1401 is integrated as one unit, and is moved by a drive system (not shown) in a direction parallel to the central axis of the cylindrical recording medium 1300 (in the direction of arrow 1305 in FIG. 13). It is configured to be able to. During this movement, a constant distance equal to or less than the wavelength of the laser beam of the semiconductor laser 1303 is maintained between the tip of the fiber probe 1310 and the outer peripheral surface of the recording medium 1300.

On the other hand, as shown in FIG. 13, the recording medium 1300 is connected to a motor 1301 and is configured to rotate at a constant rotational speed, and this rotational movement mechanism and the horizontal movement mechanism of the near-field optical pickup 1401 described above. Thus, the recording information at all positions on the recording medium 1300 can be accessed.
Inside the recording medium 1300, a photodiode (light detector) 1400 for detecting the intensity of transmitted / scattered light from the recording medium 1300 exposed to the near-field light by the near-field light irradiation unit 1304 is shown in FIG. The horizontal movement described above is performed integrally with the near-field light irradiation unit 1304.
Information is recorded on the recording medium 1300 by irradiating the rotated recording medium 1300 with pulsed near-field light modulated according to the information to be recorded (however, it has energy that changes the optical characteristics). Is done by. Here, the temporally modulated pulse-like near-field light is generated by converting light intensity-modulated by the semiconductor laser 1303 into near-field light by the fiber probe 1310.

The continuous data on the recording medium 1300 formed by this operation is arranged so as to draw a spiral on the cylindrical outer peripheral surface as shown in FIG. In FIG. 4B, the recording marks 401 arranged in the vertical direction represent a continuous data row (data track). When the cylindrical recording medium 1300 makes one round in the circumferential direction, the recording marks 401 are adjacent to each other. Connected. Specific examples of dimensions of the distance between the recording mark 401 and the data track (track pitch P) include, for example, a diameter of the recording mark 401 of 50 to 100 nm and a track pitch P of about twice the diameter of the recording mark 401. .
For reproduction (reading) of recorded information, first, the recording medium 1300 is rotated, and the near-field optical pickup is positioned so that the tip of the fiber probe 1310 is positioned on a recording mark 401 (see FIG. 4B) having information to be read. 1401 is arranged. At this time, the photodiode 1400 is disposed at a position facing the tip of the fiber probe 1310 with the recording medium 1300 interposed therebetween. In this state, the semiconductor laser 1303 is continuously turned on to generate near-field light between the tip of the fiber probe 1310 and the recording medium 1300, and transmitted / scattered light (recording) that is temporally modulated according to how the recording marks 401 are arranged. The photodiode 1400 detects the intensity of light transmitted and scattered in the space inside the medium. The photodiode 1400 detects a signal corresponding to the recording information. The track being read moves in the direction of one of the adjacent tracks in conjunction with the rotational movement of the recording medium 1300, and the near-field optical pickup 1401 moves in conjunction with this movement. By this interlocking, continuous data arranged in the form of a recording medium is read out.

(Example 7)
FIG. 15 is a conceptual diagram showing another embodiment of the optical memory device according to the present invention.
The basic configuration of this embodiment is a cylindrical recording medium 1507, a motor 1501 for supporting the recording medium 1507 at one end and rotating the recording medium 1507, and recording information on the recording medium 1507. A near-field optical pickup in which recording means for performing and reproducing means for reproducing recorded information are integrated is arranged.
As shown in FIG. 7, a recording medium 1507 has a reflective film (gold, silver, aluminum, etc.) 701 and a dielectric film (ZnS and such as a membrane by mixing the material with SiO ₂₎ 702a, a phase change film (AgInSbTe or GaAgInSbTe, etc. GeSbTe) 703, and a dielectric film (ZnS and by mixing materials with SiO ₂ film) in the order of 702b depositing a film It has a configuration.
One end (right end in the figure) of the cylinder is attached to a disk-like convex portion of the motor 1501, and the other end (left end in this case) of the cylinder is closed to prevent dust.
In addition, the recording medium 1507 is necessary for performing recording and reproduction on the recording medium 1507 by moving the recording medium 1507 in the direction of the arrow 1508 shown in FIG. 15 (such as a motor 1501 and a near-field optical pickup). It is possible to carry it separately. As shown in FIG. 11, the recording medium 1507 separated from the main body of the recording / reproducing apparatus is configured to be carried with a cap for closing the opening of the recording medium 1507.

As shown in FIG. 15, the near-field light pickup includes a near-field light irradiation unit for irradiating the recording medium 1507 with the near-field light, and a photodetector (photograph for detecting the propagation light transmitted through the recording medium 1507. Diode) 1500 comprises two parts. The near-field light irradiation unit includes a semiconductor laser 1505 that is a light source, a fiber probe 1502 that generates near-field light, and a lens 1504 that optically couples the semiconductor laser 1505 and the fiber probe 1502. A part of the probe 1502 is arranged in a space inside the recording medium 1507 through a transmission hole 1506 formed in the longitudinal direction at the center of the hollow output shaft of the motor 1501.
There is no particular limitation on the wavelength of the semiconductor laser 1505. For example, a semiconductor laser that emits light with a signal wavelength used in general optical equipment such as 780 nm, 660 nm, and 405 nm can be used. As shown in FIG. 15, the fiber probe 1502 is mounted with a support 1503 for increasing rigidity, and is inserted into a transmission hole 1506 which is a transmission means provided in the longitudinal direction at the center of the output shaft of the motor 1501. ing.

  As shown in FIG. 3, the tip of the fiber probe 1502 is coated with a metal material (eg, gold, silver, aluminum, etc.) around the core 302 sharpened in a truncated cone shape to form a metal coating layer 300. In this configuration, a minute opening (for example, an opening having a diameter of about 50 nm) 303 is formed at the tip, and light reaching the tip after being guided through the fiber probe 1502 generates near-field light in the vicinity of the minute opening 303. It is supposed to be. The diameter of the minute opening 303 is formed to be smaller than the track pitch P shown in FIG. The metal coating layer 300 is formed with a thickness that prevents light inside the core 302 from leaking to the outside, for example, a thickness of about 50 to 300 nm. The entire near-field optical pickup is integrated as one unit, and can be moved by a drive system (not shown) with respect to a direction parallel to the central axis of the cylindrical recording medium 1507 (in the direction of arrow 1508 in FIG. 15). It is configured to be able to. During this movement, the tip of the fiber probe 1502 and the inner peripheral surface of the recording medium 1507 are kept at a certain distance below the wavelength of the laser beam of the semiconductor laser 1505.

On the other hand, as shown in FIG. 15, the recording medium 1507 is connected to a motor 1501 and is configured to rotate at a constant rotational speed. This rotational motion mechanism and the horizontal movement mechanism of the near-field optical pickup described above Thus, the recording information at all positions on the recording medium 1507 can be accessed.
A photodiode (photodetector) 1500 for detecting the intensity of transmitted / scattered light from the recording medium 1507 exposed to the near-field light by the near-field light irradiation unit is disposed outside the recording medium 1507. The horizontal movement described above is performed integrally with the near-field light irradiation unit.
Information is recorded on the recording medium 1507 by irradiating the rotated recording medium 1507 with pulsed near-field light modulated according to the information to be recorded.

Here, the temporally modulated pulse-like near-field light is generated by converting the light whose intensity is modulated by the semiconductor laser 1505 into the near-field light by the fiber probe 1502. The continuous data on the recording medium 1507 formed by this operation is arranged so as to draw a spiral on the cylindrical surface as shown in FIG. In FIG. 8B, the recording marks 401 arranged in the vertical direction represent a continuous data row (data track). When the cylindrical recording medium 1507 makes one round in the circumferential direction, the recording marks 401 are adjacent to each other. Connected. Specific examples of dimensions of the distance between the recording mark 401 and the data track (track pitch P) include, for example, a diameter of the recording mark 401 of 50 to 100 nm and a track pitch P of about twice the diameter of the recording mark 401. .
In reproducing (reading) recorded information on the recording medium 1507, first, the recording medium 1507 is rotated, and the near-field optical pickup is arranged so that the tip of the fiber probe 1502 is positioned on the recording mark 401 having information to be read. . At this time, the photodiode 1500 is disposed at a position facing the tip of the fiber probe 1502 with the recording medium 1507 interposed therebetween. In this state, the semiconductor laser 1505 is continuously turned on to generate near-field light between the tip of the fiber probe 1502 and the recording medium 1507, and transmitted / scattered light that is temporally modulated according to the arrangement of the recording marks 401. The intensity of (light transmitted and scattered in the space inside the recording medium) is detected by the photodiode 1500. Thereby, a signal corresponding to the recording information is detected. The track being read moves in the direction of one of the adjacent tracks in conjunction with the rotational movement of the recording medium 1507, and the near-field optical pickup moves in conjunction with this movement. By this interlocking, continuous data arranged in the form of a recording medium is read out.

(Example 8)
16 is a conceptual diagram showing another embodiment of the optical memory device according to the present invention, and FIG. 17 is a sectional view taken along line XVII-XVII in FIG.
The basic configuration of this embodiment is a cylindrical recording medium 1600, a motor 1601 for supporting the recording medium 1600 at one end and rotating the recording medium 1600, and recording information on the recording medium 1600. A near-field optical pickup 1608 in which recording means for performing and reproducing means for reproducing recorded information are integrated is arranged as shown in FIGS. 16 and 17.
As shown in FIG. 2, the recording medium 1600 has a reflective film (gold, silver, aluminum, etc.), a dielectric film (ZnS and SiO ₂ ) on the outer peripheral surface of a cylindrical substrate formed of glass or resin. And a phase change film (AgInSbTe, GaAgInSbTe, GeSbTe, etc.), and a dielectric film (such as a film made of a mixed material of ZnS and SiO ₂ ). .

The recording medium 1600 and the motor 1601 are detachable, and the recording / reproducing apparatus main body (such as the motor 1601 and the near-field optical pickup 1608 is recorded by moving the recording medium 1600 in the direction of the arrow 1609 shown in FIG. The medium 1600 can be carried separately from the components necessary for recording and reproduction.
As shown in FIG. 17, the near-field optical pickup 1608 includes a semiconductor laser 1607 as a light source, a near-field optical probe 1602 that plays a role of generating near-field light and converting near-field light into propagating light again, and an optical path. A beam splitter 1605 for branching, a photodetector (photodiode) 1701 for detecting the light intensity modulated by the recorded information, and a lens group (objective lens 1604) for optically efficiently connecting the elements. , A collimating lens 1606, and a lens 1700). There is no particular limitation on the wavelength of the semiconductor laser 1607. For example, a semiconductor laser that emits light at a signal wavelength used in general optical equipment such as 780 nm, 660 nm, and 405 nm can be used.

FIG. 18 is a schematic diagram for explaining the operation of the optical memory device shown in FIG.
As shown in FIG. 18, the near-field light probe 1602 generates near-field light on the side surface (left side of the drawing) of the slider 1800 that floats about several to several tens of nanometers by the rotational movement of the recording medium 1600 (see FIG. 16). Therefore, a fiber probe 1801 is mounted.
The slider 1800 is made of glass, resin, or the like, and is connected to an arm 1602 for supporting the near-field optical probe 1602 via a suspension 1601. As shown in FIG. 3, the tip of the fiber probe 1801 is coated with a metal material (for example, gold, silver, aluminum, etc.) around the core 302 sharpened in a truncated cone shape to form a metal coating layer 300. In this configuration, a minute opening (for example, an opening having a diameter of about 50 nm) 303 is formed at the tip, and light reaching the tip after being guided through the fiber probe 1801 generates near-field light in the vicinity of the opening. It is like that. The diameter of the minute opening 303 is formed to be smaller than the track pitch P shown in FIG. The metal coating layer 300 is formed with a thickness that prevents light inside the core 302 from leaking to the outside, for example, a thickness of about 50 to 300 nm. The entire near-field optical pickup is integrated as a single unit, and can be moved by a drive system (not shown) in a direction parallel to the central axis of the cylindrical recording medium (in the direction of arrow 1609 in FIG. 16). It is configured as follows. During this movement, the distance between the tip of the fiber probe 1801 and the outer peripheral surface of the recording medium 1600 is always kept at a constant distance equal to or less than the wavelength of the semiconductor laser 1607 as the flying height of the slider 1800 follows the rotational speed of the recording medium 1600. It has come to droop.
As shown in FIG. 16, the recording medium 1600 is configured such that its central axis is connected to the output shaft of the motor 1601 so as to rotate at a constant rotational speed. With the horizontal movement mechanism of the field light pickup 1608, the recording information at all positions on the recording medium 1600 can be accessed.

Information is recorded on the recording medium 1600 by irradiating the rotated recording medium 1600 with pulsed near-field light modulated according to the information to be recorded.
Here, the temporally modulated pulse-like near-field light is generated by converting the light whose intensity is modulated by the semiconductor laser 1607 into the near-field light by the fiber probe 1801. The continuous data on the recording medium 1600 formed by this operation is arranged so as to draw a spiral on the cylindrical surface as shown in FIG. 4B shows a data string (data track) in which recording marks 401 arranged in the vertical direction are continuous, and a cylindrical recording medium 1600 (corresponding to 101 in FIG. 4A) is 1 in the circumferential direction. As it goes around, it is connected to the row of adjacent recording marks 401. Specific examples of dimensions of the distance between the recording mark 401 and the data track (track pitch P) include, for example, a diameter of the recording mark 401 of 50 to 100 nm and a track pitch P of about twice the diameter of the recording mark 401. .

In the optical memory device shown in FIGS. 16 to 18, reproduction (reading) of recorded information is performed by first rotating the recording medium 1600 so that the tip of the fiber probe 1801 is positioned on the recording mark 401 having information to be read. A near-field optical pickup 1608 is disposed. In this state, the semiconductor laser 1607 is continuously turned on to generate near-field light between the tip of the fiber probe 1801 and the recording medium 1600, and the return light in the fiber probe 1801 that is temporally modulated according to the arrangement of the recording marks. The intensity of light (propagating light from the opening of the tip of the fiber probe 1801 toward the beam splitter 1605) is detected by the photodiode 1607. Thereby, a signal corresponding to the recording information is detected. The track being read moves in the direction of one of the adjacent tracks in conjunction with the rotational movement of the recording medium 1600, and the near-field optical pickup 1608 moves in conjunction with the movement of the track. . By this interlocking, continuous data arranged on the recording medium 1600 is read out.
In the present embodiment, the slider 1800 in which the near-field optical probe 1602 moves and moves from the recording medium 1600 is illustrated. However, the present invention is not limited to this, and the slider 1800 may slide in contact with the recording medium 1600. .

Example 9
FIG. 19 is a conceptual diagram showing another embodiment of the near-field optical pickup used in the optical memory device according to the present invention.
In this embodiment, the configuration diagram 18 of the near-field optical probe 1602 shown in the eighth embodiment is realized by another configuration.
The near-field optical probe shown in FIG. 19 is a thin metal with a thickness of about 30 to 100 nm in which a minute opening 2000 as shown in FIG. 20 is formed on a transparent substrate (glass, resin, etc.) 1902 provided with a lens-shaped protrusion 1901. A film (gold, silver, aluminum, etc.) 1903 is provided.
FIG. 20 is a plan view showing a modification of the metal film used in the near-field optical pickup of the optical memory device according to the present invention.
Similar to the near-field optical probe 1602 shown in FIG. 17, this near-field optical probe is supported by the arm 1602 via the suspension 1601, and the near-field optical probe 1602 itself is several to several tens from the surface of the recording medium. It operates as a slider that floats at a distance of nm. The minute openings 2000 provided in the metal film 2001 are formed with the same diameter as that of the fiber probe (smaller than the track pitch P shown in FIG. 4B). The lens-shaped protrusion 1901 provided on the transparent substrate 1902 is for the light condensed by the objective lens 1900 to be further condensed toward the minute opening than when a flat substrate is used. . With such a configuration, the light is condensed up to the diffraction limit realized by the refractive index of the substrate in the minute opening.
The apparatus configuration using the near-field optical probe configured as described above and the recording and reproducing operations are the same as in the eighth embodiment.

(Example 10)
FIG. 21 is a plan view showing a modification of the transparent substrate used in the near-field optical pickup of the optical memory device according to the present invention.
In the present embodiment, the configuration diagram 18 of the near-field optical probe shown in the eighth embodiment is realized by another configuration. This near-field optical probe has a configuration in which a minute metal pattern (formed of a metal material such as gold, silver, or aluminum) is formed on the transparent substrate 1902 instead of the minute aperture shown in the ninth embodiment. Yes.
Examples of the shape of the metal pattern include the configurations shown in FIGS. In the configuration of FIG. 21, a minute scatterer (a metal pattern formed of a metal material such as gold, silver, or aluminum) 2100 having a size about the diameter of the tip of the fiber probe is formed on the transparent substrate 1902 in the eighth embodiment. In this configuration, near-field light is generated in the vicinity of the metal pattern by condensing and irradiating light onto the minute scatterer 2100.

In the configuration of FIG. 22, two substantially triangular fine metal patterns 2200a and 2200b are arranged to face each other so as to be line-symmetric, and light is transmitted between the two patterns (portion shown as a minute gap 2201 in FIG. 22). Is configured to generate near-field light by condensing and irradiating light. The value of the minute gap 2201 is about several tens of nm. In the case of the near-field optical probe using any of the configurations shown in FIGS. 21 and 24, the near-field optical probe itself is supported by the arm 1602 via the suspension 1601 as in the near-field optical probe of FIG. It operates as a slider that floats at a distance of several to several tens of nanometers from the surface of the recording medium.
The apparatus configuration using the near-field optical probe configured as described above and the recording and reproducing operations are the same as in the eighth embodiment.

(Example 11)
FIG. 23 is a conceptual diagram showing another embodiment of the optical memory device according to the present invention. 24 is a sectional view taken along line XXIV-XXIV in FIG.
The basic configuration of this embodiment is a cylindrical recording medium 2300, a motor 2301 for supporting the recording medium 2300 at one end and rotating the recording medium 2300, and recording information on the recording medium 2300. The recording means for performing and the near-field optical pickup integrated with the reproducing means for reproducing the recorded information are arranged as shown in FIGS.
As shown in FIG. 2, the recording medium 2300 has a reflective film (gold, silver, aluminum, etc.), a dielectric film (ZnS and SiO ₂ ) on the outer peripheral surface of a cylindrical substrate formed of glass or resin. And a phase change film (AgInSbTe, GaAgInSbTe, GeSbTe, etc.), and a dielectric film (such as a film made of a mixed material of ZnS and SiO ₂ ). .

The recording medium 2300 and the motor 2301 are detachable, and the recording / reproducing apparatus main body (recording medium such as a motor 2301 or a near-field optical pickup is moved by moving the recording medium 2300 in the direction of the arrow 2306 shown in FIG. 2300 can be carried separately from the components necessary for recording and reproduction.
As shown in FIG. 24, the near-field light pickup is disposed in the inner space of the recording medium 2300 and the near-field light irradiation unit 2306 for irradiating the recording medium 2300 with the near-field light, and passes through the recording medium 2300. It comprises two parts of a photodetector (photodiode) 2307 for detecting the propagated light.

  The near-field light irradiation unit 2306 includes a semiconductor laser 2304 as a light source, a near-field light probe 2302 that generates near-field light, and an objective lens 2303 for optically efficiently coupling the light source 2304 and the near-field light probe 2302. It consists of and. There is no particular limitation on the wavelength of the semiconductor laser 2304. For example, a semiconductor laser that emits light with a signal wavelength used in general optical equipment such as 780 nm, 660 nm, and 405 nm can be used. As shown in FIG. 18, the near-field light probe has a configuration in which a fiber probe 1801 for generating near-field light is mounted on the side surface of the slider 1800 that floats about several to several tens of nanometers by the rotational movement of the recording medium. ing. The slider 1800 is made of glass, resin, or the like, and is connected to an arm 1602 for supporting the near-field optical probe via a suspension 1601. As shown in FIG. 3, the tip of the fiber probe 1801 is coated with a metal material (for example, gold, silver, aluminum, etc.) around the core 302 sharpened in a truncated cone shape to form a metal coating layer 300, It has a structure in which a minute opening (for example, an opening having a diameter of about 50 nm) 303 is formed at the tip, and light that reaches the tip after being guided through the fiber probe 1801 generates near-field light in the vicinity of the minute opening 303. It is supposed to be. The diameter of the minute opening 303 is formed to be smaller than the track pitch P shown in FIG. The metal coating layer 300 is formed with a thickness of about 50 to 300 nm, for example, so that the light inside the core 303 does not leak outside. The entire near-field optical pickup is integrated as a single unit, and can be moved by a drive system (not shown) in a direction parallel to the central axis of the cylindrical recording medium (in the direction of arrow 2306 in FIG. 23). It is configured as follows. During this movement, a constant distance equal to or less than the wavelength of the light source (semiconductor laser 2304) is maintained between the tip of the fiber probe 2302 and the outer peripheral surface of the recording medium 2300.

On the other hand, as shown in FIG. 23, the recording medium 2300 is connected to a motor 2301 and is configured to rotate at a constant rotational speed. This rotational movement mechanism and the horizontal movement mechanism of the near-field optical pickup described above. Can be moved in the direction of the arrow 2310, and the recording information at all positions on the recording medium 2300 can be accessed. A photodiode (light detector) 2307 for detecting the intensity of transmitted / scattered light from the recording medium 2300 exposed to the near-field light by the near-field light irradiation unit 2306 is provided inside the recording medium 2300 as shown in FIG. And the horizontal movement described above is performed integrally with the near-field light irradiation unit 2306.
Information is recorded on the recording medium 2300 by irradiating the rotating recording medium 2300 with pulsed near-field light modulated according to the information to be recorded.

Here, the temporally modulated pulse-like near-field light is generated by converting light intensity-modulated by the semiconductor laser 2304 into near-field light by the fiber probe 2302. The continuous data on the recording medium 2300 formed by this operation is arranged so as to draw a spiral on a cylindrical surface as shown in FIG. In FIG. 4B, the recording marks 401 arranged in the vertical direction represent a continuous data row (data track). When a cylindrical recording medium makes one round in the circumferential direction, it is connected to the row of adjacent recording marks 401. It has come to be.
Specific examples of dimensions of the distance between the recording mark 401 and the data track (track pitch P) include, for example, a diameter of the recording mark 401 of 50 to 100 nm and a track pitch P of about twice the diameter of the recording mark 401. .
In reproducing (reading) recorded information on the recording medium 2300, first, the recording medium 2300 is rotated so that the tip of the fiber probe 2302 is positioned on the recording mark 401 (see FIG. 4B) having information to be read. The near-field optical pickup 2306 is disposed at the center. At this time, the photodiode 2307 is disposed at a position facing the tip of the fiber probe 2302 with the recording medium 2300 interposed therebetween. In this state, the semiconductor laser 2304 is continuously turned on to generate near-field light between the tip of the fiber probe 2302 and the recording medium 2300, and transmitted / scattered light (recording) that is temporally modulated according to how the recording marks 401 are arranged. The intensity of light transmitted and scattered in the space inside the medium 2300 is detected by the photodiode 2307. By detecting the photodiode 2307, a signal corresponding to the recording information is detected. The track being read moves in the direction of one of the adjacent tracks in conjunction with the rotational movement of the recording medium 2300, and the near-field optical pickup 2306 moves in conjunction with this movement. Yes. By this interlocking, continuous data arranged on the recording medium 2300 is read out.
In the present embodiment, the slider in which the near-field optical probe 2302 is lifted from the recording medium 2300 is exemplified. However, the present invention is not limited to this, and may be configured to slide in contact with the recording medium 2300.

(Example 12)
In this embodiment, the configuration diagram 18 of the near-field optical probe shown in the embodiment 11 is realized by another configuration.
In this near-field optical probe, as shown in FIG. 19, a micro-opening 2000 as shown in FIG. 20 is formed on a transparent substrate (formed of glass or resin) 1902 provided with a lens-shaped protrusion 1901. In addition, a thin metal film (gold, silver, aluminum, etc.) 1903 of about 30 to 100 nm is provided. This near-field optical probe is supported by an arm 1904 via a suspension 1905 in the same manner as the near-field optical probe in FIG. 18, and the near-field optical probe itself floats at a distance of several to several tens of nm from the surface of the recording medium. It works as a slider. The minute openings 2000 provided in the metal film 1903 are formed with the same diameter (smaller than the track pitch P in FIG. 4B) as that of the fiber probe. The lens-shaped protrusion 1901 provided on the transparent substrate 1903 allows the light condensed by the objective lens to be condensed toward the minute opening 2000 more than when the flat transparent substrate 1902 is used. Is for. With this configuration, the minute opening 2000 collects light up to the diffraction limit realized by the refractive index of the transparent substrate 1902.
The apparatus configuration and recording / reproducing operations using the near-field optical probe configured as described above are the same as those in the eleventh embodiment.

(Example 13)
In this embodiment, the configuration diagram 18 of the near-field optical probe shown in the embodiment 11 is realized by another configuration.
This near-field optical probe has a configuration in which a minute metal pattern (formed of a metal material such as gold, silver, or aluminum) is formed on a substrate instead of the minute aperture shown in the twelfth embodiment. Examples of the shape of the metal pattern include FIG. 21 and FIG. In the configuration shown in FIG. 21, a minute scatterer (a metal pattern formed of a metal material such as gold, silver, or aluminum) having a size approximately equal to the diameter of the tip of the fiber probe is formed on the transparent substrate in Example 11. In this configuration, near-field light is generated near the metal pattern by collecting and irradiating light.
FIG. 22 is a plan view showing a modification of the transparent substrate used in the near-field optical pickup of the optical memory device according to the present invention.
In the configuration shown in FIG. 22, two triangular metal patterns 2200a and 2200b are arranged to face each other, and light is condensed and irradiated between the two patterns (portion shown as a minute gap 2201 in FIG. 22). Is configured to generate near-field light. The value of the minute gap 2201 is about several tens of nm. In the case of the near-field optical probe using any of the configurations shown in FIGS. 21 and 22, the near-field optical probe is supported by the arm 1602 via the suspension 1601 similarly to the near-field optical probe shown in FIG. The device itself operates as a slider that floats at a distance of several to several tens of nanometers from the surface of the recording medium.
The apparatus configuration and recording / reproducing operations using the near-field optical probe configured as described above are the same as those in the eleventh embodiment.

(Example 14)
25 and 26 are conceptual diagrams showing other embodiments of the near-field optical pickup used in the optical memory device according to the present invention.
This embodiment shows a configuration example of a recording medium. As shown in FIG. 25 or FIG. 26, the recording medium main body has a configuration in which protective films 2501 and 2601 are provided on the outer peripheral surface or the inner peripheral surface. Yes.
Here, the recording medium main body is a recording medium configured as shown in FIGS. In the configuration shown in FIG. 25, a protective film using a material such as silicon nitride (SiN) or diamond-like carbon is provided on the outer surface of the recording medium in FIG. 2 with a thickness of about 5 to 15 nm. . Similarly, in the configuration shown in FIG. 26, a protective film using a material such as silicon nitride (SiN) or diamond-like carbon is provided on the inner peripheral surface of the recording medium 500 shown in FIG. It becomes the composition.
In the case of the configuration shown in FIG. 25, the recording medium configured as described above is used in place of the recording medium of the above embodiment in which the apparatus is configured using the recording medium shown in FIG. In this case, the recording medium 500 shown in FIG. 7 is used instead of the recording medium of the above-described embodiment in which the apparatus is configured. Recording and reproduction operations when the apparatus is configured using these recording media are the same as those described in the corresponding embodiments.

1 is a conceptual diagram illustrating an embodiment of an optical memory device according to the present invention. It is the II-II sectional view taken on the line of the recording medium used for the optical memory device shown in FIG. It is a longitudinal cross-sectional view of the fiber probe used for the optical memory device shown in FIG. (A) is an external perspective view of a recording medium used in the optical memory device shown in FIG. 1, and (b) is a partially enlarged view of the outer peripheral surface of the recording medium shown in (a). It is a conceptual diagram which shows the other Example of the optical memory device based on this invention. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. FIG. 7 is a sectional view taken along line VII-VII of a recording medium used in the optical memory device shown in FIG. 5. (A) is an external perspective view of a recording medium used in the optical memory device shown in FIG. 5, and (b) is a partially enlarged view of the inner peripheral surface of the recording medium shown in (a). It is a conceptual diagram which shows the other Example of the optical memory device based on this invention. FIG. 10 is an external perspective view showing a state where a cap 1000 is put on the recording medium shown in FIG. 9. It is sectional drawing which shows the other Example of the recording medium used for the optical memory device based on this invention. It is sectional drawing which shows the other Example of the recording medium used for the optical memory device based on this invention. It is a conceptual diagram which shows the other Example of the optical memory device based on this invention. It is the XIV-XIV sectional view taken on the line of FIG. It is a conceptual diagram which shows the other Example of the optical memory device based on this invention. It is a conceptual diagram which shows the other Example of the optical memory device based on this invention. It is the XVII-XVII sectional view taken on the line of FIG. FIG. 17 is a schematic diagram for explaining the operation of the optical memory device shown in FIG. 16. It is a conceptual diagram which shows the other Example of the near-field optical pick-up used for the optical memory device based on this invention. It is a top view which shows the modification of the metal film used for the near-field optical pick-up of the optical memory device based on this invention. It is a top view which shows the modification of the transparent substrate used for the near-field optical pick-up of the optical memory device based on this invention. These are the top views which show the modification of the transparent substrate used for the near-field optical pick-up of the optical memory device based on this invention. It is a conceptual diagram which shows the other Example of the optical memory device based on this invention. It is the XXIV-XXIV sectional view taken on the line of FIG. It is a conceptual diagram which shows the other Example of the near-field optical pick-up used for the optical memory device based on this invention. It is a conceptual diagram which shows the other Example of the near-field optical pick-up used for the optical memory device based on this invention. It is explanatory drawing of the basic concept of the near-field optical memory device as a prior art example of an optical memory device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Motor 101 Recording medium 102 Fiber probe 103 Objective lens 104 Beam splitter 105 Collimating lens 106 Lens 107 Photo diode 108 Semiconductor laser 109 Near-field optical pickup

Claims (9)

A cylindrical recording medium having a recording film whose optical characteristics change in response to energy of an electromagnetic field;
A recording means for recording information on the recording medium by irradiating near-field light with an energy that changes the optical characteristics;
An optical memory device comprising: reproducing means for reading the recorded information by return light when irradiated with near-field light having an energy that does not change the optical characteristics. A cylindrical recording medium having a recording film whose optical characteristics change in response to energy of an electromagnetic field;
A recording means for recording information on the recording medium by irradiating near-field light with an energy that changes the optical characteristics;
An optical memory device comprising: reproducing means for detecting propagation light transmitted and scattered in the recording film and reading the recorded information.   The optical memory device according to claim 1, wherein at least a part of the recording unit and the reproducing unit is provided in a space inside the recording medium having the cylindrical shape. An output shaft for rotating the recording medium is hollow, and a motor coaxial with the recording medium;
Provided in the space of the output shaft of the motor, and provided with a transmission means for allowing light to pass between the inner peripheral surface of the cylindrical recording medium and the space and the outside of the output shaft. The optical memory device according to claim 3.   2. The optical memory device according to claim 1, wherein the recording medium has a configuration in which at least a recording film of a recording film and a dielectric film is laminated on a cylindrical substrate using a metal material.   The optical memory device according to claim 1, wherein the recording medium is provided with a protective film on an inner peripheral surface or an outer peripheral surface of a cylinder.   3. The optical memory according to claim 1, wherein the recording unit or the reproducing unit includes a structure using a metal material that is formed on a transparent substrate and generates or scatters near-field light. apparatus. 3. The optical memory device according to claim 1, wherein the recording unit or the reproducing unit includes a slider that floats or slides with respect to a surface of the recording medium.   3. A protective cap that is used by being attached to the recording medium when the recording medium is separated from a reproducing apparatus main body provided with the near-field optical head. An optical memory device according to claim 1.

Images