WO2011081108A1 - Dispositif et procédé de traitement de données optiques - Google Patents

Dispositif et procédé de traitement de données optiques Download PDF

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Publication number
WO2011081108A1
WO2011081108A1 PCT/JP2010/073450 JP2010073450W WO2011081108A1 WO 2011081108 A1 WO2011081108 A1 WO 2011081108A1 JP 2010073450 W JP2010073450 W JP 2010073450W WO 2011081108 A1 WO2011081108 A1 WO 2011081108A1
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WIPO (PCT)
Prior art keywords
wavelength
optical information
recording medium
light
control data
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PCT/JP2010/073450
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English (en)
Japanese (ja)
Inventor
龍一 片山
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日本電気株式会社
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Priority to JP2011547670A priority Critical patent/JPWO2011081108A1/ja
Publication of WO2011081108A1 publication Critical patent/WO2011081108A1/fr

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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/083—Disposition or mounting of heads or light sources relatively to record carriers relative to record carriers storing information in the form of optical interference patterns, e.g. holograms
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/125—Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
    • G11B7/126—Circuits, methods or arrangements for laser control or stabilisation
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
    • G11B7/0065—Recording, reproducing or erasing by using optical interference patterns, e.g. holograms
    • G11B2007/00656—Counterpropagating holography
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
    • G11B7/0065—Recording, reproducing or erasing by using optical interference patterns, e.g. holograms

Definitions

  • the present invention relates to an optical information processing apparatus and an optical information processing method that perform at least one of recording information on an optical information recording medium and reproducing information recorded on the optical information recording medium.
  • a technique for recording information on an optical information recording medium a technique is known which is performed depending on whether or not a diffraction grating is formed on the optical information recording medium.
  • the diffraction grating two coherent light beams facing each other are condensed on an optical information recording medium, and standing waves generated by the interference between the two light beams alter the recording material (recording layer). It is formed.
  • this is used to form a diffraction grating when recording binarized information “1” and recording binarized information “0” at the time of recording information. No diffraction grating is formed.
  • the information is recorded depending on whether or not the diffraction grating is formed according to the information recorded at the recording position of the optical information recording medium.
  • a technique for reproducing information recorded on an optical information recording medium a technique is known which is performed by detecting reflected light from a diffraction grating formed on the optical information recording medium.
  • a diffraction grating is formed on the optical information recording medium, if the light beam having the same condition as one of the two light beams used at the time of recording is focused on the recording position from one side of the optical information recording medium The light beam is reflected by the diffraction grating.
  • the diffraction grating is not formed at the recording position of the optical information recording medium, the beam light is not reflected even if the light beam is condensed at the recording position from one surface side of the optical information recording medium ( That is, it is transmitted).
  • the beam light having the same condition as one of the two light beams used at the time of recording is transmitted from one surface side of the optical information recording medium to the recording position.
  • the binarized information “1” is reproduced.
  • the binarized information “0” is reproduced. That is, in this reproduction technique, recorded information is reproduced by detecting reflected light from the recording position of the optical information recording medium.
  • information recording is performed depending on whether or not a diffraction grating is formed at the recording position of the optical information recording medium.
  • the reflected light of the light beam irradiated to the recording position of the optical information recording medium is reflected.
  • Information reproduction can be performed depending on whether or not it is detected.
  • information recorded / reproduced at each recording position is 1 bit, the recording capacity is limited and a sufficient recording capacity may not be obtained.
  • Patent Document 1 discloses a wavelength multiplexing recording / reproducing technique used for page-type hologram recording.
  • an information recording operation performed at each recording position of the optical information recording medium is performed at a constant wavelength. For example, when an information recording operation is performed three times depending on whether or not a diffraction grating is formed at a constant wavelength, 3-bit information can be recorded.
  • wavelength multiplexing reproduction performs information reproducing operation performed at each recording position of the optical information recording medium using the same wavelength as that during the information recording operation. For example, when the information reproducing operation is performed three times depending on whether or not the reflected light of the beam light is detected at a certain wavelength, 3-bit information can be reproduced.
  • the optical information recording medium is altered every time a diffraction grating is formed during information recording, and the refractive index of the recording position changes.
  • the optical information recording medium has a refractive index change threshold ( ⁇ n) that allows a change in refractive index, and information is recorded when a refractive index change exceeding the threshold ( ⁇ n) is applied to the recording position of the optical information recording medium. Can not.
  • the refractive index change threshold ( ⁇ n) is ⁇ n ⁇ 1
  • the number of diffraction gratings that can be formed at the same position is limited by the refractive index change threshold ( ⁇ n) and the diffraction efficiency ( ⁇ ). That is, the number of bits that can be recorded / reproduced at the recording position is determined by the refractive index change and the diffraction efficiency when the diffraction grating is formed. For this reason, the conventional technique has a problem that more information recording / reproduction cannot be performed.
  • the present invention has been made in view of the above circumstances, and an optical information processing apparatus and an optical information recording / reproducing apparatus that record and reproduce more information while the number of diffraction gratings that can be formed at each recording position is limited.
  • the purpose is to provide an information processing method.
  • An optical information processing apparatus includes: An optical information processing apparatus that performs at least one of recording and reproduction of information on an optical information recording medium, Wavelength control data storage means for storing wavelength control data indicating information for controlling the wavelength of the light beam focused on the optical information recording medium in association with each recording information that can be recorded on the optical information recording medium; , When recording or reproducing information, a beam that acquires one or a plurality of the wavelength control data from the wavelength control data storage means, and focuses on the optical information recording medium based on the acquired one or a plurality of wavelength control data Control means for controlling the wavelength of light.
  • An optical information processing method includes: An optical information processing method for performing at least one of information recording and reproduction on an optical information recording medium, Predetermined wavelength storage data indicating information for controlling the wavelength of the light beam condensed on the optical information recording medium for each recording information that can be recorded on the optical information recording medium when recording or reproducing information
  • FIG. 1 is a diagram showing an optical information recording medium according to an embodiment of the present invention. It is a figure which shows the structure of the optical unit which concerns on embodiment of this invention. It is the figure (the 1) which showed the wavelength dependence of the wavelength filter which concerns on embodiment of this invention. It is the figure (the 2) which showed the wavelength dependence of the wavelength filter which concerns on embodiment of this invention. It is the figure (the 3) which showed the wavelength dependence of the wavelength filter which concerns on embodiment of this invention.
  • the optical information processing apparatus 1 is roughly divided into a controller 11, a wavelength control data storage unit 12, an optical unit driving unit 13, and a condensing point moving mechanism driving unit 14.
  • the optical unit 100 and the condensing point moving mechanism 140 are provided. With these configurations, the optical information processing apparatus 1 records information on the optical information recording medium 2 and reproduces information recorded on the optical information recording medium 2.
  • the controller 11 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and is configured to centrally control the optical information processing apparatus 1.
  • CPU Central Processing Unit
  • ROM Read Only Memory
  • RAM Random Access Memory
  • the controller 11 reads out an information recording / reproducing program stored in the ROM or the like in response to a request for information recording or a request for reproducing information input via an operation unit (not shown), and expands and executes the information recording / reproducing program in the RAM or the like. As a result, the optical information processing apparatus 1 is comprehensively controlled.
  • the controller 11 records information on an optical information recording medium 2 supplied from a recording data input unit or a storage unit (not shown), and a recording request signal indicating an information recording request supplied via an operation unit or the like. Record data to be received. Then, the controller 11 performs control to record information at each recording position of the optical information recording medium 2.
  • the recording data received by the controller 11 is information (for example, “100001100110...”) Representing the data in a bit string.
  • the controller 11 divides the received recording data according to the number of bits recorded at each recording position of the optical information recording medium 2. In the present embodiment, since the number of bits of information recorded at each recording position of the optical information recording medium 2 is “2”, the controller 11 is “10”, “00”, “01”. Divide the received recording data.
  • the controller 11 acquires the wavelength control data corresponding to the divided recording data from the wavelength control data storage unit 12, and operates the optical unit driving unit 13 based on the information indicated by the acquired wavelength control data.
  • the controller 11 receives a reproduction request signal indicating an information reproduction request supplied via an operation unit or the like and reproduces information recorded at each recording position of the optical information recording medium 2 during information reproduction. Do.
  • the controller 11 acquires all the wavelength control data from the wavelength control data storage unit 12, and operates the optical unit driving unit 13 based on each wavelength control data.
  • the controller 11 determines a point at which the optical unit 100 condenses the beam light on the optical information recording medium 2 during information recording and information reproduction (hereinafter referred to as a condensing point) and a surface of the optical information recording medium 2.
  • a movement control signal for moving to a recording position in the thickness direction is supplied to the condensing point moving mechanism driving unit 14.
  • the wavelength control data storage unit 12 associates wavelength control data indicating information for controlling the wavelength of the light beam focused on the optical information recording medium 2 with recording information that can be recorded at each recording position of the optical information recording medium 2. I remember.
  • the wavelength control data storage unit 12 has the corresponding light beam wavelengths of “ ⁇ 1”, “ ⁇ 2”, “ ⁇ 3”, “ ⁇ 4” (in accordance with the information that can be recorded, respectively). Wavelength control data 1 to 4 for controlling to satisfy ⁇ 1 ⁇ 2 ⁇ 3 ⁇ 4) are stored.
  • Each wavelength control data has shutter information indicating which one of shutters 106a to 106d of the optical unit 100 to be described later is opened during information recording and information reproduction (see FIG. 4).
  • Each wavelength control data includes light reception information indicating which one of photodetectors 110a to 110d of the optical unit 100 (to be described later) is a light reception target during information reproduction (see FIG. 4).
  • the optical unit driving unit 13 applies various driving voltages to the optical unit 100 in order to operate the optical unit 100 under the control of the controller 11.
  • the optical unit 100 is operated by various driving voltages applied by the optical unit driving unit 13.
  • the condensing point moving mechanism driving unit 14 applies a driving voltage or the like to the condensing point moving mechanism 140 in order to operate the condensing point moving mechanism 140 under the control of the controller 11.
  • the condensing point moving mechanism 140 is operated by a driving voltage or the like applied by the condensing point moving mechanism driving unit 14 and records the condensing point in the optical information recording medium 2 in the surface and thickness direction of the optical information recording medium 2. Move to position.
  • the condensing point moving mechanism 140 performs tracking control that rotates the optical information recording medium 2 and causes the condensing point to follow the track so that the condensing point is located at a predetermined position.
  • the optical information recording medium 2 includes a recording layer 202 sandwiched between two substrates 201a and 201b.
  • the material of the substrates 201a and 201b for example, glass is used, and as the material of the recording layer 202, for example, a photopolymer is used.
  • the recording layer 202 has a plurality of recording positions in its surface and thickness direction.
  • the optical unit 100 includes light sources 101a to 101d, lenses 102a to 102f, wavelength filters 103a to 103f, an active wavelength plate 104, a polarizing beam splitter 105, shutters 106a to 106d, mirrors, and the like. 107a to 107d, quarter wave plates 108a and 108b, objective lenses 109a and 109b, and photodetectors 110a to 110d.
  • the light sources 101a to 101d operate when a constant current is supplied, and each emits light having a different wavelength. Specifically, the light source 101a emits light of wavelength “ ⁇ 1”, the light source 101b emits light of wavelength “ ⁇ 2”, the light source 101c emits light of wavelength “ ⁇ 3”, and the light source 101d emits light of wavelength “ ⁇ 4”. As the light sources 101a to 101d, for example, semiconductor lasers can be employed.
  • the shutters 106a to 106d are provided on the optical paths of the beam lights emitted from the corresponding light sources 101a to 101d, respectively.
  • the shutters 106a to 106d are opened when a voltage is applied.
  • the shutters 106a to 106d transmit the beam light when the shutter 106a is opened, and block (not transmit) the beam light when the shutter 106a is closed.
  • the shutters 106a to 106d for example, ferroelectric liquid crystal shutters are used.
  • the light beam having the wavelength “ ⁇ 1” transmitted through the shutter 106a becomes two-way light beams 60a and 61a facing each other through the optical information recording medium 2, as shown in FIG. 6A.
  • the beam light 60a having the wavelength “ ⁇ 1” is incident on the center position of the one objective lens 109a and passes through the objective lens 109a to be converged light and condensed on the optical information recording medium 2.
  • the beam light 61 a having the wavelength “ ⁇ 1” is incident on the center position of the other objective lens 109 a and is condensed from this position toward the recording position of the recording layer 202 of the optical information recording medium 2.
  • the light beams 60a and 61a having the wavelength “ ⁇ 1” are condensed at the same position of the recording layer 202 of the optical information recording medium 2 and interfere with each other, thereby forming the diffraction grating 203a corresponding to the wavelength “ ⁇ 1”. .
  • the light beams 60b and 61b having the wavelength “ ⁇ 2” interfere with each other, thereby forming the diffraction grating 203b corresponding to the wavelength “ ⁇ 2”.
  • the light beams 60c and 61c having the wavelength “ ⁇ 3” interfere with each other, thereby forming the diffraction grating 203c corresponding to the wavelength “ ⁇ 3”.
  • the light beams 60d and 61d having the wavelength “ ⁇ 4” interfere with each other, thereby forming the diffraction grating 203d corresponding to the wavelength “ ⁇ 4”.
  • the wavelength filters 103a to 103c are provided on the optical path of the beam light that passes through the corresponding shutters 106a to 106d, respectively.
  • the wavelength filters 103d to 103f are provided on the optical paths through which the beam light enters the photodetectors 110a to 110d, respectively.
  • a beam splitter that transmits or reflects the beam light according to the wavelength of the incident beam light is used.
  • the wavelength filters 103a and 103d transmit light having a wavelength ⁇ 1, and reflect light having wavelengths “ ⁇ 2” to “ ⁇ 4”.
  • the wavelength filters 103b and 103e transmit light having wavelengths “ ⁇ 1” to “ ⁇ 3” and reflect light having wavelength “ ⁇ 4”.
  • the wavelength filters 103c and 103f reflect light having wavelengths “ ⁇ 1” and “ ⁇ 2” and transmit light having wavelengths “ ⁇ 3” and “ ⁇ 4”.
  • the lenses 102a to 102f respectively convert incident light from divergent light into parallel light or from parallel light into convergent light.
  • the lenses 102a to 102e as shown in FIG. 4, spherical lenses having convex shapes on both sides are adopted, but the shape of the lenses is not limited.
  • a spherical lens having a concave shape on both sides a spherical lens having a convex shape on one side and a concave shape on the other side, or an aspherical lens may be used.
  • the active wavelength plate 104 is provided on the optical path of the beam light that passes through the lens 102a.
  • the active wave plate 104 operates when a voltage is applied, and the function as a quarter wave plate and the function as a half wave plate are switched according to the applied voltage.
  • the active wavelength plate 104 is configured by sandwiching a liquid crystal layer such as a nematic liquid crystal having a uniaxial refractive index anisotropy between two substrates.
  • a transparent electrode for applying an AC voltage to the liquid crystal layer is provided on the surface of the two substrates facing the liquid crystal layer.
  • the direction of the optical axis of the liquid crystal layer is a direction perpendicular to the optical axis of incident light and a direction parallel to the optical axis.
  • the direction is intermediate (wavelength 45 °).
  • the phase difference between the polarization component in the direction parallel to the plane including the optical axis and the optical axis generated in the light transmitted through the liquid crystal layer and the polarization component in the direction perpendicular to the plane is ⁇ / 2
  • the active wave plate 104 functions as a quarter-wave plate.
  • the active wave plate 104 that functions as a quarter wave plate converts incident linearly polarized light into circularly polarized light.
  • the direction of the optical axis of the liquid crystal layer becomes a direction perpendicular to the optical axis of the incident light.
  • the phase difference between the polarization component in the direction parallel to the plane including the optical axis and the optical axis generated in the light transmitted through the liquid crystal layer and the polarization component in the direction perpendicular thereto is ⁇
  • the active wave plate 104 is 1 / It functions as a two-wave plate.
  • the active wave plate 104 functioning as a half-wave plate changes the polarization direction of the incident linearly polarized light by 90 degrees.
  • the polarization beam splitter 105 is provided on the optical path of the beam light that passes through the active wavelength plate 104.
  • the polarization beam splitter 105 transmits the P-polarized component beam light parallel to the incident surface, and reflects the S-polarized component beam light perpendicular to the incident surface.
  • the polarization beam splitter 105 splits the optical path into a first optical path and a second optical path according to the polarization component of the beam light incident from the active wave plate 104.
  • the mirrors 107a to 107d are arranged to change the optical path and guide the beam light incident from the former member to the latter member.
  • the quarter-wave plates 108a and 108b convert linearly polarized light into circularly polarized light when the incident beam light is linearly polarized light, and convert circularly polarized light into linearly polarized light when the incident beam light is circularly polarized light.
  • the objective lenses 109a and 109b face each other via the optical information recording medium 2, and light beams in the first optical path that the objective lens 109a collects and light beams in the second optical path that the objective lens 109b collects are light.
  • the information recording medium 2 is arranged so as to be condensed at the same position.
  • the objective lenses 109a and 109b are spherical lenses having convex surfaces as shown in FIG. 4, but the shape of the lenses is not limited. For example, a spherical lens having a concave shape on both sides, a spherical lens having a convex shape on one side and a concave shape on the other side, or an aspherical lens may be used.
  • the photodetectors 110a to 110d are provided on the optical path of the beam light transmitted or reflected by the wavelength filters 103d to 103f, respectively.
  • the photodetectors 110a to 110d receive the beam lights emitted from the corresponding light sources 101a to 101d, respectively.
  • the photodetectors 110a to 110d are constituted by light receiving elements such as a CCD (Charge Coupled Device) and a PIN photodiode, for example.
  • the optical unit driving unit 13 includes a shutter driving unit 21, an active wavelength plate driving unit 22, a light source driving unit 23, and a received light signal acquisition unit 24.
  • the shutter drive unit 21 receives from the controller 11 a shutter control signal for controlling the shutters 106a to 106d. Then, the shutter driving unit 21 applies a predetermined voltage to the shutter to be opened indicated by the shutter control signal among the shutters 106a to 106d.
  • the active wave plate driving unit 22 receives an active wave plate control signal from the controller 11 and applies a predetermined voltage to the active wave plate 104 according to the active wave plate control signal. Specifically, the active wave plate driving unit 22 causes the active wave plate 104 to function as a quarter wave plate by applying an alternating voltage (for example, 2.5 V) having a predetermined effective value during information recording. Further, by applying an AC voltage (for example, 0 V) having a predetermined effective value during information reproduction, the active wavelength plate 104 is caused to function as a half-wave plate.
  • an alternating voltage for example, 2.5 V
  • an AC voltage for example, 0 V
  • the light source driving unit 23 receives a light source control signal for controlling the light source 101 from the controller 11 and supplies a constant current to the light source 101 according to the light source control signal.
  • the light reception signal acquisition unit 24 receives the light reception signals from the light-detected photodetectors 110a to 110d during information reproduction, thereby identifying the light-detected photodetectors 110a to 110d, and information on the identified photodetectors.
  • the received light information is supplied to the controller 11.
  • the operation of the optical information processing apparatus 1 is roughly divided into an information recording operation for recording information on the optical information recording medium 2 and an information reproducing operation for reproducing information recorded on the optical information recording medium 2.
  • the controller 11 records on a recording request signal for requesting information recording input via an operation unit or the like, and an optical information recording medium 2 supplied from a recording data input unit or storage unit (not shown).
  • the recording data is received, and the information recording program stored in the ROM or the like is read according to the received data, and the program is developed on the RAM or the like and executed.
  • the controller 11 receives the recording data “1000011100110...”
  • the number of bits of information to be recorded at each recording position of the optical information recording medium 2 is “2”.
  • the received recording data is divided as “00”, “01”.
  • the controller 11 sequentially acquires the wavelength control data corresponding to the divided recording data from the wavelength control data storage unit 12.
  • the controller 11 has “wavelength control data 3” corresponding to “10”, “wavelength control data 1” corresponding to “00”, “wavelength control data 2” corresponding to “01”, and so on.
  • the wavelength control data is sequentially acquired from the wavelength control data storage unit 12.
  • the controller 11 supplies a movement control signal for driving the condensing point moving mechanism 140 to the condensing point moving mechanism driving unit 14.
  • the condensing point moving mechanism driving unit 14 applies a driving voltage or the like for operation to the condensing point moving mechanism 140.
  • the condensing point moving mechanism 140 is operated by a driving voltage applied by the condensing point moving mechanism driving unit 14 and is first at a position where information is recorded (position of the upper left corner of the recording layer 202 shown in FIG. 3). Control so that the focal point is located.
  • the condensing point moving mechanism 140 performs tracking control that rotates the optical information recording medium 2 and causes the condensing point to follow the track.
  • the controller 11 supplies a shutter control signal for controlling the shutter 106c to the shutter drive unit 21 based on the shutter information 3 indicated by the “wavelength control data 3” corresponding to “10”. In response to this, the shutter drive unit 21 applies a voltage to the shutter 106c to open the shutter 106c.
  • the controller 11 supplies an active wave plate control signal for causing the active wave plate 104 to function as a quarter wave plate to the active wave plate driving unit 22.
  • the active wave plate driving unit 22 applies an AC voltage (for example, 2.5 V) having a predetermined effective value to cause the active wave plate 104 to function as a quarter wave plate.
  • the controller 11 supplies a light source control signal for controlling the light sources 101a to 101d to the light source driving unit 23.
  • the light source driver 23 supplies a constant current to the light sources 101a to 101d to operate the light sources 101a to 101d.
  • the light source 101a emits beam light (linearly polarized light) having a wavelength “ ⁇ 1”, the light source 101b has a wavelength “ ⁇ 2”, the light source 101c has a wavelength “ ⁇ 3”, and the light source 101d has a wavelength “ ⁇ 4”.
  • the light beams emitted from the light sources 101a to 101d are incident on shutters 106a to 106d provided on the respective optical paths.
  • the light beams having four wavelengths incident on the shutters 106a to 106d are transmitted through the open shutter 106c and are not transmitted through the other shutters 106a, 106b, and 106d.
  • the light beam having the wavelength “ ⁇ 3” transmitted through the shutter 106c passes through the wavelength filters 103c and 103b, is collimated by the lens 102a, and is converted from linearly polarized light to circularly polarized light by the active wavelength plate 104 functioning as a quarter wavelength plate. Then, the light enters the polarization beam splitter 105.
  • the S-polarized component beam light 60 c (about 50% of the incident light) is reflected by the polarizing beam splitter 105.
  • the light beam 60c is incident on the center position of the objective lens 109a through the lens 102b, the mirror 107a, the lens 102c, the mirror 107b, and the quarter wavelength plate 108a.
  • the beam light 60c passes through the objective lens 109a to become convergent light and is condensed at the recording position (position where information is first recorded) of the recording layer 202 of the optical information recording medium 2.
  • the P-polarized component beam light 61c (about 50% of the incident light) out of the circularly polarized light incident on the polarizing beam splitter 105 is transmitted through the polarizing beam splitter 105.
  • the beam light 61c enters the center position of the objective lens 109b through the lens 102d, the mirror 107c, the lens 102e, the mirror 107d, and the quarter wavelength plate 108b as shown in FIG. 6C. Then, the beam light 61c passes through the objective lens 109b and becomes convergent light and is condensed at the recording position (position where information is first recorded) of the recording layer 202 of the optical information recording medium 2.
  • the two light beams 60 c and 61 c having the wavelength “ ⁇ 3” facing each other are condensed on the optical information recording medium 2 at the recording position of the recording layer 202 of the optical information recording medium 2. Then, the light beams 60c and 61c interfere with each other at this recording position, whereby the diffraction grating 203c corresponding to the wavelength “ ⁇ 3” is formed. Thereby, information recording corresponding to the first recording data “10” of the recording data divided by the controller 11 is performed at the recording position of the optical information recording medium 2 where information is first recorded.
  • the controller 11 supplies a movement control signal for driving the condensing point moving mechanism 140 to the condensing point moving mechanism driving unit 14.
  • the condensing point moving mechanism driving unit 14 applies a driving voltage or the like to the condensing point moving mechanism 140.
  • the condensing point moving mechanism 140 is operated by a driving voltage or the like applied by the condensing point moving mechanism driving unit 14, and is next at a position where information is recorded (position of the upper left corner of the recording layer 202 shown in FIG. 3). Control so that the focal point is located.
  • the condensing point moving mechanism 140 performs tracking control that rotates the optical information recording medium 2 and causes the condensing point to follow the track.
  • wavelength control data 1 (“wavelength control data 1”) corresponding to the remaining divided recording data (“00”, “01”, “10”, “01”, “10”%) Acquired by the controller 11. ”,“ Wavelength control data 2 ”,“ wavelength control data 3 ”,“ wavelength control data 2 ”,“ wavelength control data 3 ”...
  • the light beams having the wavelength “ ⁇ 1”, the wavelength “ ⁇ 2”, the wavelength “ ⁇ 3”, the wavelength “ ⁇ 2”, and the wavelength “ ⁇ 3” are sequentially collected at each recording position of the optical information recording medium 2, respectively. Diffraction gratings corresponding to the wavelength of the light beam are sequentially formed.
  • recording data (“10000100100 —”) Can be recorded on the optical information recording medium 2.
  • the controller 11 receives a reproduction request signal for requesting information reproduction input via the operation unit or the like, reads out an information reproduction program stored in the ROM or the like in response to this, and stores the information reproduction program in the RAM or the like. Expand and run.
  • the controller 11 performs all the wavelength control data (wavelength control data 1) stored in the wavelength control data storage unit 12 in accordance with a reproduction request for the recorded data (“100001100110...”) Recorded at the time of information recording. To 4).
  • the controller 11 supplies a movement control signal for operating the condensing point moving mechanism 140 to the condensing point moving mechanism driving unit 14. Accordingly, the condensing point moving mechanism driving unit 14 applies a driving voltage or the like to the condensing point moving mechanism 140.
  • the condensing point moving mechanism 140 is operated by the driving voltage applied by the condensing point moving mechanism driving unit 14 and is collected at a position where the first information is reproduced (the upper left corner position of the recording layer 202 shown in FIG. 3). Control so that the light spot is located.
  • the condensing point moving mechanism 140 performs tracking control that rotates the optical information recording medium 2 and causes the condensing point to follow the track.
  • the controller 11 operates all the shutters 106a to 106d based on the shutter information indicated by the “wavelength control data 1”, “wavelength control data 2”, “wavelength control data 3”, and “wavelength control data 4”.
  • the shutter control signal is supplied to the shutter drive unit 21.
  • the shutter drive unit 21 applies a voltage to the shutters 106a to 106d to open the shutters 106a to 106d.
  • the controller 11 supplies an active wave plate control signal for causing the active wave plate 104 to function as a half wave plate to the active wave plate driving unit 22.
  • the active wave plate driving unit 22 applies an AC voltage (for example, 0 V) having a predetermined effective value to the active wave plate 104 to cause the active wave plate 104 to function as a half wave plate.
  • the controller 11 supplies a light source control signal for operating the light sources 101a to 101d to the light source driving unit 23.
  • the light source driver 23 supplies a constant current to the light sources 101a to 101d to operate the light sources 101a to 101d.
  • the light source 101a emits a light beam having a wavelength “ ⁇ 1”
  • the light source 101b emits a light beam having a wavelength “ ⁇ 2”
  • the light source 101c emits a light beam having a wavelength “ ⁇ 3”
  • the light source 101d emits a light beam having a wavelength “ ⁇ 4”.
  • the light beams emitted from the light sources 101a to 101d are incident on the corresponding shutters 106a to 106d.
  • the shutters 106a to 106d are all open, and the light beams incident on the shutters 106a to 106d are transmitted through the shutters 106a to 106d.
  • the light beam having the wavelength “ ⁇ 1” transmitted through the shutter 106a is transmitted through the wavelength filter 103a and reflected by the wavelength filter 103b.
  • the light beam having the wavelength “ ⁇ 2” transmitted through the shutter 106b is reflected by the wavelength filters 103a and 103b.
  • the light beam having the wavelength “ ⁇ 3” transmitted through the shutter 106c is transmitted through the wavelength filters 103c and 103b.
  • the light beam having the wavelength “ ⁇ 4” transmitted through the shutter 106d is reflected by the wavelength filter 103c and passes through the wavelength filter 103b.
  • the S-polarized component light beams 70 a to 70 d which are about 100% of the light beam incident on the polarizing beam splitter 105 are reflected by the polarizing beam splitter 105. Then, the recording position of the recording layer 202 of the optical information recording medium 2 (the position where information is first recorded) via the lens 102b, the mirror 107a, the lens 102c, the mirror 107b, the quarter wavelength plate 108a, and the objective lens 109a. It is focused on.
  • the light beams of wavelengths “ ⁇ 1” to “ ⁇ 4” are recorded on the recording layer of the optical information recording medium 2 from one surface side (objective lens 109a side).
  • the light is condensed at the recording position 202.
  • the diffraction grating 203c is formed by the light beams 60c and 61c having the wavelength “ ⁇ 3” at the recording position where the information on the recording layer 202 of the optical information recording medium 2 is first recorded. Therefore, as shown in FIG. 8C, only the light beam 70c having the wavelength “ ⁇ 3” is reflected by the diffraction grating 203c, and the other light beams 70a, 70b, and 70d having the wavelengths “ ⁇ 1”, “ ⁇ 2”, and “ ⁇ 4” are reflected. Passes through the recording position.
  • the reflected beam light 70c ′ reflected by the diffraction grating 203c is polarized through the objective lens 109a, the quarter wavelength plate 108a, the mirror 107b, the lens 102c, the mirror 107a, and the lens 102b in the direction opposite to the above direction.
  • the light enters the splitter 105.
  • the light beam of the P-polarized component that is about 100% of the light beam incident on the polarization beam splitter 105 passes through the polarization beam splitter 105.
  • the light beam having the wavelength “ ⁇ 3” that has passed through the polarization beam splitter 105 passes through the wavelength filters 103f and 103e and is received by the photodetector 110c.
  • the light detector 110 c that has received the beam light supplies a light reception signal to the light reception signal acquisition unit 24 of the optical unit driving unit 13.
  • the received light signal acquisition unit 24 identifies the photodetector 110c that has detected the reflected beam light 70c ′ by receiving the received light signal, and supplies the received light information (light reception information 3) indicating the identified photodetector 110c to the controller 11. To do.
  • the controller 11 acquires “wavelength control data 3” corresponding to the received light information 3 from the wavelength control data storage unit 12, and acquires information “10” associated with the “wavelength control data 3”. .
  • the first information “10” recorded at the recording position of the optical information recording medium 2 is reproduced.
  • the controller 11 supplies a movement control signal for driving the condensing point moving mechanism driving unit 14 to the condensing point moving mechanism driving unit 14.
  • the condensing point moving mechanism driving unit 14 applies a driving voltage or the like to the condensing point moving mechanism 140.
  • the condensing point moving mechanism 140 is operated by the driving voltage applied by the condensing point moving mechanism driving unit 14 and is collected at a position where the next information is reproduced (position of the upper left corner of the recording layer 202 shown in FIG. 3). Control so that the light spot is located.
  • the condensing point moving mechanism 140 performs tracking control that rotates the optical information recording medium 2 and causes the condensing point to follow the track.
  • the controller 11 sequentially stores information “00” associated with “wavelength control data 1” and information “01” associated with “wavelength control data 2”.
  • the information “10”... Associated with the “wavelength control data 3”, and so on, are acquired as 2-bit information associated with the sequentially acquired wavelength control data.
  • the recorded data (“100001100110...”) Recorded at the time of information recording can be reproduced.
  • 2-bit information recording / reproduction can be performed by performing control of condensing using the beam light of [lambda] 3 "," [lambda] 4 "), and forming one diffraction grating at each recording position.
  • the refractive index change assigned to one diffraction grating is ⁇ n.
  • the optical information processing apparatus 1 of the present embodiment can increase the diffraction efficiency of the diffraction grating four times as compared with the conventional one. As described above, according to the optical information processing apparatus 1 of the present embodiment, more information can be recorded and reproduced while the number of diffraction gratings that can be formed at each recording position is limited.
  • the wavelength interval ( ⁇ ) of the beam light condensed on the optical information recording medium 2 is affected by crosstalk, which is the ratio of the signal level received from another diffraction grating to the signal level received from the diffraction grating to be reproduced. You must avoid it. That is, it is necessary not to receive reflected beam light from a diffraction grating other than the diffraction grating to be reproduced.
  • the size in the optical axis direction of the beam light condensed on the recording layer 202 of the optical information recording medium 2 via the objective lenses 109a and 109b is ⁇ for the wavelength of light used for recording and reproduction, and the numerical apertures of the objective lenses 109a and 109b.
  • the diffraction efficiency (reflectance) of the diffraction grating when the wavelength of the beam light condensed on the optical information recording medium 2 is changed is obtained by the coupled wave theory.
  • the relationship between the beam light focused on the optical information recording medium 2 during information reproduction and the diffraction efficiency of the diffraction grating (the relationship between the recording wavelength and the reproduction wavelength) will be described.
  • the horizontal axis represents the reproduction wavelength
  • the vertical axis represents the signal level obtained by normalizing the diffraction efficiency of the diffraction grating with the value when the reproduction wavelength matches the recording wavelength.
  • four curves obtained when the recording wavelengths are “ ⁇ 1” to “ ⁇ 4” are superimposed. In any of the recording wavelengths “ ⁇ 1” to “ ⁇ 4”, the signal level is 1 when the reproduction wavelength matches the recording wavelength.
  • the signal level decreases as the reproduction wavelength moves away from the recording wavelength, and the signal level becomes almost zero when the reproduction wavelength is separated from the recording wavelength by ⁇ . In this case, reflected beam light from a diffraction grating other than the diffraction grating to be reproduced is not received.
  • the light reception signal level when the light is condensed under the condition of wavelength ⁇ 1 during information reproduction is 1, and the light is collected under the conditions of wavelengths ⁇ 2, ⁇ 3, and ⁇ 4.
  • the signal level in this case is almost zero. That is, it can be seen that reflected beam light from a diffraction grating other than the diffraction grating to be reproduced is not received and is not affected by crosstalk.
  • the mode in which 2-bit information recording / reproduction is performed at each recording position of the optical information recording medium 2 has been described.
  • the present invention is not limited to recording / reproduction of 2-bit information.
  • the number of bits that can be recorded is arbitrary as long as the following conditions are satisfied for the information to be recorded on the optical information recording medium 2 and the wavelength of the light beam focused on the optical information recording medium 2.
  • 2 d ⁇ p C q d number of bits of information to be recorded at each recording position of the optical information recording medium 2 d ; number of information p; set number of wavelengths of beam light that can be condensed at each recording position of the optical information recording medium 2 q; Selectable number of light beam wavelengths to choose from possible light beams
  • the wavelength control data storage unit 12 stores wavelength control data for controlling the wavelength of the beam light in association with each other for each piece of information of a plurality of bits.
  • the number of diffraction gratings formed at each recording position of the optical information recording medium 2 is small. Therefore, it is better that the number of light beams to be selected is small. For example, when expressing 2-bit recording information using four wavelengths (“ ⁇ 1” to “ ⁇ 4”), it is better to select one wavelength than to select two wavelengths from the four wavelengths. By doing so, one diffraction grating is formed, the refractive index change is smaller than when two diffraction gratings are formed, and the diffraction efficiency is not lowered.
  • the beam light focused on the optical information recording medium 2 is selected using the shutters 106a to 106d, but the present invention is not limited to this configuration.
  • the configuration may be such that the light beams emitted from the light sources 101a to 101d are selected without using the shutters 106a to 106d.
  • the wavelength control data includes light source information indicating which of the light sources 101a to 101d is to be driven instead of the shutter information.
  • the controller 11 may supply a light source control signal for controlling a light source to be driven to the light source driving unit 23, the shutter driving unit 21 becomes unnecessary, and the number of parts can be reduced.
  • a plurality of light sources 101a to 101d that emit light beams having different wavelengths are used.
  • a single variable wavelength unit that can emit light beams having different wavelengths is used.
  • the wavelength control data includes wavelength information indicating the wavelength of light emitted from the wavelength tunable light source 101 ′.
  • the number of parts can be reduced.
  • a light source control signal for emitting beam light having a wavelength (in this case, “ ⁇ 1”) corresponding to recording information (for example, “00”) is supplied to the wavelength variable light source 101 ′.
  • the wavelength tunable light source 101 ′ emits beam light having a wavelength “ ⁇ 1”, whereby a diffraction grating 203 a is formed at the recording position of the recording layer 202 of the optical information recording medium 2.
  • only one photodetector 110 ′ for receiving beam light at the time of information reproduction is sufficient. That is, at the time of information reproduction, light beams of wavelengths “ ⁇ 1” to “ ⁇ 4” corresponding to all wavelength control data are sequentially emitted from the wavelength variable light source 101 '. Each time, the controller 11 determines whether or not there is a light reception signal supplied from the photodetector 110 '. Thereby, the wavelength (for example, “ ⁇ 1”) when the light beam is received can be specified, and the information (for example, “00”) corresponding to the specified light reception information (for example, light reception information 1) can be reproduced. .
  • the optical information processing apparatus 1 uses the light beam that can be collected on the optical information recording medium 2 based on the data size of the requested recording data and the memory capacity of the optical information recording medium 2 at the time of recording.
  • the number (q) of light beams to be selected and the number of bits (d) may be determined.
  • the number (p) of light beams that can be focused on the optical information recording medium 2 is five (wavelengths “ ⁇ 1” to “ ⁇ 5”), and there are 60 remaining recording positions on the optical information recording medium 2.
  • the optical information processing apparatus 1 determines the number of bits (d) of information to be recorded at each recording position as 2 bits.
  • the optical information processing apparatus 1 sets the number of bits (d) of information to be recorded at each recording position to 3
  • Optical information processing apparatus Optical information recording medium 11 Controller 12 Wavelength control data memory

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Head (AREA)
  • Optical Recording Or Reproduction (AREA)

Abstract

L'invention concerne un dispositif (1) de traitement de données optiques qui comporte: une unité (12) de stockage de données de commande de longueur d'onde qui stocke des données de commande de longueur d'onde comportant des données de commande de la longueur d'onde d'un faisceau lumineux, concentré sur un support (2) d'enregistrement de données optiques, en association avec chacune des données enregistrées pouvant être enregistrée sur ledit support (2); et un organe de commande (11) qui acquiert une ou plusieurs données de commande de longueur d'onde provenant de l'unité (12) de stockage de données de commande de longueur d'onde au moment où des données sont enregistrées ou reproduites, et qui commande la longueur d'onde du faisceau lumineux concentré sur le support (2) d'enregistrement de données optiques, sur la base des données de commande de longueur d'onde acquises.
PCT/JP2010/073450 2009-12-28 2010-12-24 Dispositif et procédé de traitement de données optiques WO2011081108A1 (fr)

Priority Applications (1)

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JP2011547670A JPWO2011081108A1 (ja) 2009-12-28 2010-12-24 光学的情報処理装置及び光学的情報処理方法

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JP2009-298856 2009-12-28

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2506256A3 (fr) * 2011-03-31 2013-10-16 General Electric Company Systèmes et procédés holographiques à longueur d'onde multiple
JP2015176610A (ja) * 2014-03-13 2015-10-05 シチズンホールディングス株式会社 光記録装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006228375A (ja) * 2005-02-21 2006-08-31 Alps Electric Co Ltd ホログラフィー記録装置，再生装置及びその方法並びにホログラフィー媒体
WO2007060718A1 (fr) * 2005-11-24 2007-05-31 Fujitsu Limited Dispositif d’enregistrement holographique

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006228375A (ja) * 2005-02-21 2006-08-31 Alps Electric Co Ltd ホログラフィー記録装置，再生装置及びその方法並びにホログラフィー媒体
WO2007060718A1 (fr) * 2005-11-24 2007-05-31 Fujitsu Limited Dispositif d’enregistrement holographique

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2506256A3 (fr) * 2011-03-31 2013-10-16 General Electric Company Systèmes et procédés holographiques à longueur d'onde multiple
JP2015176610A (ja) * 2014-03-13 2015-10-05 シチズンホールディングス株式会社 光記録装置

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