WO2011081108A1 - Optical information processing device, and optical information processing method - Google Patents

Optical information processing device, and optical information processing method 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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WO
WIPO (PCT)
Prior art keywords
wavelength
optical information
recording medium
light
control data
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Application number
PCT/JP2010/073450
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French (fr)
Japanese (ja)
Inventor
龍一 片山
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日本電気株式会社
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Application filed by 日本電気株式会社 filed Critical 日本電気株式会社
Priority to JP2011547670A priority Critical patent/JPWO2011081108A1/en
Publication of WO2011081108A1 publication Critical patent/WO2011081108A1/en

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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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Abstract

An optical information processing device (1) is provided with: a wavelength control data storing unit (12) which stores wavelength control data presenting information for controlling the wavelength of a beam light, which is concentrated onto an optical information recording medium (2), in association with each recorded information which could be recorded onto the optical information recording medium (2); and a controller (11) which acquires one or more wavelength control data from the wavelength control data storing unit (12) when information is being recorded or reproduced, and which controls the wavelength of the beam light, which is concentrated onto the optical information recording medium (2), on the basis of the acquired wavelength control data.

Description

光学的情報処理装置及び光学的情報処理方法Optical information processing apparatus and optical information processing method
　本発明は、光情報記録媒体への情報の記録及び光情報記録媒体に記録した情報の再生の少なくとも何れか一方を行う光学的情報処理装置及び光学的情報処理方法に関する。 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.
　光情報記録媒体に情報を記録する技術として、光情報記録媒体に回折格子を形成するか否かにより行う技術が知られている。回折格子は、互いに対向する可干渉性を有する２つのビーム光が光情報記録媒体に集光し、これらが互いに干渉することで発生する定在波が記録材料（記録層）を変質することで形成される。上記の記録技術では、このことを利用して、情報記録時に、二値化された情報“１”を記録する場合に回折格子を形成し、二値化された情報“０”を記録する場合に回折格子を形成しない。このように、上記の記録技術では、光情報記録媒体の記録位置に記録する情報に応じて、回折格子を形成するか否かにより当該情報を記録する。 As 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. In 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. In the above-described recording technique, 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. As described above, in the recording technique described above, 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.
　また、光情報記録媒体に記録した情報を再生する技術として、光情報記録媒体に形成した回折格子からの反射光を検出することにより行う技術が知られている。光情報記録媒体に回折格子が形成されている場合、記録時に用いた２つのビーム光のうち一方のビーム光と同じ条件のビーム光を光情報記録媒体の一面側から当該記録位置に集光すると、そのビーム光は回折格子で反射される。これに対して、光情報記録媒体の記録位置に回折格子が形成されていない場合、ビーム光を光情報記録媒体の一面側から当該記録位置に集光しても、そのビーム光は反射されない（即ち、透過する）。このことを利用して、上記の再生技術では、情報再生時に、記録時に用いた二つのビーム光のうち一方のビーム光と同じ条件のビーム光を光情報記録媒体の一面側から当該記録位置に集光し、その反射光が検出された場合は、記録時に回折格子が形成されているので二値化された情報“１”を再生する。一方、反射光が検出されない場合は二値化された情報“０”を再生する。即ち、この再生技術では、光情報記録媒体の記録位置からの反射光の検出を行うことにより、記録された情報を再生する。 Further, as 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. When 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. On the other hand, when 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). By utilizing this, in the above reproduction technique, at the time of information reproduction, 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. When the light is condensed and the reflected light is detected, since the diffraction grating is formed at the time of recording, the binarized information “1” is reproduced. On the other hand, when the reflected light is not detected, 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.
　このように、上記従来の技術では、光情報記録媒体の記録位置に回折格子を形成するか否かにより情報記録を行い、一方、光情報記録媒体の記録位置に照射するビーム光の反射光が検出されるか否かにより情報再生を行うことができる。しかし、各記録位置で記録・再生される情報は１ビットであるため、記録容量に限界があり、十分な記録容量が得られないことがある。 As described above, in the conventional technique, information recording is performed depending on whether or not a diffraction grating is formed at the recording position of the optical information recording medium. On the other hand, 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. However, since information recorded / reproduced at each recording position is 1 bit, the recording capacity is limited and a sufficient recording capacity may not be obtained.
　光情報記録媒体の記録容量を増大する技術として、光情報記録媒体の各記録位置に複数ビットの情報を記録し、再生する技術（いわゆる、多重記録再生技術）が提案されている（特許文献１参照）。特許文献１には、ページ型のホログラム記録に用いられている波長多重記録再生技術が開示されている。 As a technique for increasing the recording capacity of an optical information recording medium, a technique for recording and reproducing information of multiple bits at each recording position of the optical information recording medium (so-called multiple recording / reproducing technique) has been proposed (Patent Document 1). reference). Patent Document 1 discloses a wavelength multiplexing recording / reproducing technique used for page-type hologram recording.
　波長多重記録は、光情報記録媒体の各記録位置で行う情報記録動作を一定の波長で行う。例えば、一定の波長で回折格子を形成するか否かにより行う情報記録動作を３回行った場合、３ビットの情報を記録することができる。 In wavelength multiplexing 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.
　また、波長多重再生は、光情報記録媒体の各記録位置で行う情報再生動作を、情報記録動作時と同じ波長を用いて行う。例えば、一定の波長でビーム光の反射光が検出されるか否かにより行う情報再生動作を３回行った場合、３ビットの情報を再生することができる。 In addition, 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.
特開２００８－２０３７７２号公報JP 2008-203772 A
　光情報記録媒体は、情報記録時に回折格子が形成される毎に変質され、その記録位置の屈折率が変化する。光情報記録媒体には、屈折率変化を許容する屈折率変化閾値（Δｎ）が存在し、この閾値（Δｎ）を超える屈折率変化を光情報記録媒体の記録位置に与えた場合、情報が記録できない。 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 (Δn) that allows a change in refractive index, and information is recorded when a refractive index change exceeding the threshold (Δn) is applied to the recording position of the optical information recording medium. Can not.
　また、屈折率変化閾値（Δｎ）がΔｎ≪１であり、同一位置にＮ個の回折格子が形成された場合の回折格子の回折効率（η）は、η＝（Δｎ／Ｎ）２となり、回折格子の数が増えるにつれ、回折効率（η）は大きく低下する。 Further, the refractive index change threshold (Δn) is Δn << 1, and the diffraction efficiency (η) of the diffraction grating when N diffraction gratings are formed at the same position is η = (Δn / N) 2 , As the number of diffraction gratings increases, the diffraction efficiency (η) decreases significantly.
　このように、同一位置に形成できる回折格子の数は、屈折率変化閾値（Δｎ）や回折効率（η）によって制限される。つまり、記録位置に記録再生可能なビット数は、回折格子を形成した時の屈折率変化や回折効率により決まる。このため、従来の技術では、より多くの情報記録再生を行うことができないという問題があった。 Thus, the number of diffraction gratings that can be formed at the same position is limited by the refractive index change threshold (Δn) and the diffraction efficiency (η). 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.
　本発明は、上記実情に鑑みてなされたものであり、各記録位置に形成できる回折格子の数が制限されている中で、より多くの情報の記録や再生を行う光学的情報処理装置及び光学的情報処理方法を提供することを目的とする。 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.
　本発明の第１の観点に係る光学的情報処理装置は、
　光情報記録媒体に対して、情報の記録及び再生の少なくとも何れか一方を行う光学的情報処理装置であって、
　前記光情報記録媒体に記録され得る記録情報毎に、前記光情報記録媒体に集光するビーム光の波長を制御するための情報を示す波長制御データを対応付けて記憶した波長制御データ記憶手段と、
　情報の記録又は再生の際、前記波長制御データ記憶手段から１又は複数の前記波長制御データを取得し、取得した１又は複数の波長制御データに基づいて、前記光情報記録媒体に集光するビーム光の波長を制御する制御手段と、を備える、ことを特徴とする。 An optical information processing apparatus according to a first aspect of the present invention 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.
　本発明の第２の観点に係る光学的情報処理方法は、
　光情報記録媒体に対して、情報の記録及び再生の少なくとも何れか一方を行う光学的情報処理方法であって、
　情報の記録又は再生の際、前記光情報記録媒体に記録され得る記録情報毎に、前記光情報記録媒体に集光するビーム光の波長を制御するための情報を示す波長制御データを記憶する所定のメモリから、１又は複数の前記波長制御データを取得する波長制御データ取得工程と、
　該波長制御データ取得工程で取得された１又は複数の波長制御データに基づいて、前記光情報記録媒体に集光するビーム光の波長を制御する制御工程と、を有する、ことを特徴とする。 An optical information processing method according to a second aspect of the present invention 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 A wavelength control data acquisition step of acquiring one or a plurality of the wavelength control data from the memory;
And a control step of controlling the wavelength of the beam light condensed on the optical information recording medium based on one or a plurality of wavelength control data acquired in the wavelength control data acquisition step.
　本発明によれば、各記録位置に形成できる回折格子の数が制限されている中で、より多くの情報の記録や再生を行うことができる。 According to the present invention, more information can be recorded and reproduced while the number of diffraction gratings that can be formed at each recording position is limited.
本発明の実施形態に係る光学的情報処理装置の構成を示すブロック図である。It is a block diagram which shows the structure of the optical information processing apparatus which concerns on embodiment of this invention. 本発明の実施形態に係る波長制御データ記憶部に記憶された波長制御データのデータ構造を示す図である。It is a figure which shows the data structure of the wavelength control data memorize | stored in the wavelength control data storage part which concerns on embodiment of this invention. 本発明の実施形態に係る光情報記録媒体を示す図である。1 is a diagram showing an optical information recording medium according to an embodiment of the present invention. 本発明の実施形態に係る光学ユニットの構成を示す図である。It is a figure which shows the structure of the optical unit which concerns on embodiment of this invention. 本発明の実施形態に係る波長フィルタの波長依存性を示した図（その１）である。It is the figure (the 1) which showed the wavelength dependence of the wavelength filter which concerns on embodiment of this invention. 本発明の実施形態に係る波長フィルタの波長依存性を示した図（その２）である。It is the figure (the 2) which showed the wavelength dependence of the wavelength filter which concerns on embodiment of this invention. 本発明の実施形態に係る波長フィルタの波長依存性を示した図（その３）である。It is the figure (the 3) which showed the wavelength dependence of the wavelength filter which concerns on embodiment of this invention. 情報記録時において波長λ１で光情報記録媒体の記録位置に集光されるビーム光を示す図である。It is a figure which shows the beam light condensed by the recording position of an optical information recording medium with the wavelength (lambda) 1 at the time of information recording. 情報記録時において波長λ２で光情報記録媒体の記録位置に集光されるビーム光を示す図である。It is a figure which shows the beam light condensed by the recording position of an optical information recording medium with wavelength (lambda) 2 at the time of information recording. 情報記録時において波長λ３で光情報記録媒体の記録位置に集光されるビーム光を示す図である。It is a figure which shows the beam light condensed by the recording position of an optical information recording medium with wavelength (lambda) 3 at the time of information recording. 情報記録時において波長λ４で光情報記録媒体の記録位置に集光されるビーム光を示す図である。It is a figure which shows the beam light condensed by the recording position of an optical information recording medium with the wavelength (lambda) 4 at the time of information recording. 本発明の実施形態に係る光学ユニット駆動部の内部構成を示すブロック図である。It is a block diagram which shows the internal structure of the optical unit drive part which concerns on embodiment of this invention. 情報再生時において波長λ１で光情報記録媒体の記録位置に集光されるビーム光を示す図である。It is a figure which shows the beam light condensed by the recording position of an optical information recording medium with the wavelength (lambda) 1 at the time of information reproduction. 情報再生時において波長λ２で光情報記録媒体の記録位置に集光されるビーム光を示す図である。It is a figure which shows the beam light condensed by the recording position of an optical information recording medium with wavelength (lambda) 2 at the time of information reproduction. 情報再生時において波長λ３で光情報記録媒体の記録位置に集光されるビーム光を示す図である。It is a figure which shows the beam light condensed by the recording position of an optical information recording medium with wavelength (lambda) 3 at the time of information reproduction. 情報再生時において波長λ４で光情報記録媒体の記録位置に集光されるビーム光を示す図である。It is a figure which shows the beam light condensed by the recording position of an optical information recording medium with the wavelength (lambda) 4 at the time of information reproduction. 情報記録時に形成した回折格子に集光するビーム光の波長と信号レベルとの関係を示した図である。It is the figure which showed the relationship between the wavelength of the beam light condensed on the diffraction grating formed at the time of information recording, and a signal level. 本発明の実施形態に係る光学ユニットの別の構成を示す図である。It is a figure which shows another structure of the optical unit which concerns on embodiment of this invention.
　本発明の一実施形態について図面を参照して説明する。本実施形態では、光情報記録媒体の各記録位置に２ビットの情報記録再生を行う態様について説明する。 An embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a mode in which 2-bit information recording / reproduction is performed at each recording position of the optical information recording medium will be described.
　光学的情報処理装置１は、図１に示すように、その構成を大きく分けると、コントローラ１１と、波長制御データ記憶部１２と、光学ユニット駆動部１３と、集光点移動機構駆動部１４と、光学ユニット１００と、集光点移動機構１４０と、を備えている。光学的情報処理装置１は、これらの構成により、光情報記録媒体２に情報の記録を行い、また、光情報記録媒体２に記録された情報の再生を行う。 As shown in FIG. 1, 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.
　コントローラ１１は、ＣＰＵ（Ｃｅｎｔｒａｌ　Ｐｒｏｃｅｓｓｉｎｇ　Ｕｎｉｔ）、ＲＯＭ（Ｒｅａｄ　Ｏｎｌｙ　Ｍｅｍｏｒｙ）、ＲＡＭ（Ｒａｎｄｏｍ　Ａｃｃｅｓｓ　Ｍｅｍｏｒｙ）等を有し、光学的情報処理装置１を統括的に制御するように構成されている。 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.
　コントローラ１１は、図示しない操作部等を介して入力される情報記録の要求又は情報再生の要求に応じてＲＯＭ等に記憶された情報記録再生プログラムを読み出し、これをＲＡＭ等に展開して実行することにより、光学的情報処理装置１を統括的に制御する。 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.
　コントローラ１１は、情報記録時において、操作部等を介して供給される情報記録の要求を示す記録要求信号と、図示しない記録データ入力部や記憶部等から供給される光情報記録媒体２に記録する記録データとを受け取る。そして、コントローラ１１は、光情報記録媒体２の各記録位置に情報を記録する制御を行う。コントローラ１１が受け取る記録データはデータをビット列で表した情報（例えば“１００００１１００１１０・・・”）である。 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.
　コントローラ１１は、受け取った記録データを、光情報記録媒体２の各記録位置に記録するビット数に応じて分割する。本実施の形態では、光情報記録媒体２の各記録位置に記録する情報のビット数が“２”なので、コントローラ１１は、“１０”、“００”、“０１”・・・、というように受け取った記録データを分割する。 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.
　コントローラ１１は、分割した記録データに対応する波長制御データを波長制御データ記憶部１２から取得し、取得した波長制御データが示す情報に基づいて、光学ユニット駆動部１３を動作させる。 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.
　また、コントローラ１１は、情報再生時において、操作部等を介して供給される情報再生の要求を示す再生要求信号を受け取り、光情報記録媒体２の各記録位置に記録した情報を再生する制御を行う。コントローラ１１は、波長制御データ記憶部１２から全ての波長制御データを取得し、各波長制御データに基づいて、光学ユニット駆動部１３を動作させる。 In addition, 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.
　さらに、コントローラ１１は、情報記録時及び情報再生時において、光学ユニット１００が光情報記録媒体２にビーム光を集光する点（以下、集光点という）を、光情報記録媒体２の面及び厚さ方向の記録位置に移動させるための移動制御信号を集光点移動機構駆動部１４に供給する。 Further, 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.
　波長制御データ記憶部１２は、光情報記録媒体２の各記録位置に記録され得る記録情報に、光情報記録媒体２に集光するビーム光の波長を制御する情報を示す波長制御データを対応付けて記憶している。 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.
　本実施形態では、光情報記録媒体２の各記録位置に記録する情報のビット数が“２”なので、記録され得る情報は、“００”、“０１”、“１０”、“１１”の４種類となる。したがって、波長制御データ記憶部１２は、図２に示すように、これら記録され得る情報に応じて、それぞれ対応するビーム光の波長が“λ１”、“λ２”、“λ３”、“λ４”（λ１＜λ２＜λ３＜λ４）になるように制御するための波長制御データ１～４を記憶している。 In this embodiment, since the number of bits of information to be recorded at each recording position of the optical information recording medium 2 is “2”, the information that can be recorded is “00”, “01”, “10”, “11”. It becomes a kind. Therefore, as shown in FIG. 2, the wavelength control data storage unit 12 has the corresponding light beam wavelengths of “λ1”, “λ2”, “λ3”, “λ4” (in accordance with the information that can be recorded, respectively). Wavelength control data 1 to 4 for controlling to satisfy λ1 <λ2 <λ3 <λ4) are stored.
　各波長制御データは、情報記録時及び情報再生時において、後述する光学ユニット１００のシャッタ１０６ａ～１０６ｄのうちの何れを開くかを示したシャッタ情報を有する（図４参照）。また、各波長制御データは、情報再生時において、後述する光学ユニット１００の光検出器１１０ａ～１１０ｄのうちの何れを受光対象とするかを示した受光情報を有する（図４参照）。 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).
　光学ユニット駆動部１３は、コントローラ１１の制御の下、光学ユニット１００を動作させるため、光学ユニット１００に各種の駆動電圧等を印加する。 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.
　光学ユニット１００は、光学ユニット駆動部１３により印加される各種の駆動電圧等により動作する。 The optical unit 100 is operated by various driving voltages applied by the optical unit driving unit 13.
　集光点移動機構駆動部１４は、コントローラ１１の制御の下、集光点移動機構１４０を動作させるため、集光点移動機構１４０に駆動電圧等を印加する。 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.
　集光点移動機構１４０は、集光点移動機構駆動部１４により印加される駆動電圧等により動作し、光情報記録媒体２における集光点を光情報記録媒体２の面及び厚さ方向の記録位置に移動する。また、集光点移動機構１４０は、光情報記録媒体２を回転させると共に、予め定められた位置に集光点が位置するように、トラックに集光点を追従させるトラッキング制御を行う。 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. In addition, 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.
　光情報記録媒体２は、図３に示すように、２枚の基板２０１ａ、２０１ｂの間に記録層２０２が挟まれて構成されている。基板２０１ａ、２０１ｂの材料としては、例えばガラスが用いられ、記録層２０２の材料としては例えば、フォトポリマが用いられる。記録層２０２は、その面及び厚さ方向に複数の記録位置を有する。 As shown in FIG. 3, the optical information recording medium 2 includes a recording layer 202 sandwiched between two substrates 201a and 201b. As 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.
　次に、光学ユニット１００の具体的な構成について説明する。光学ユニット１００は、図４に示すように、光源１０１ａ～１０１ｄと、レンズ１０２ａ～１０２ｆと、波長フィルタ１０３ａ～１０３ｆと、アクティブ波長板１０４と、偏光ビームスプリッタ１０５と、シャッタ１０６ａ～１０６ｄと、ミラー１０７ａ～１０７ｄと、１／４波長板１０８ａ，１０８ｂと、対物レンズ１０９ａ，１０９ｂと、光検出器１１０ａ～１１０ｄと、を備えている。 Next, a specific configuration of the optical unit 100 will be described. As shown in FIG. 4, 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.
　光源１０１ａ～１０１ｄは、一定の電流が供給されることにより動作し、それぞれが異なる波長の光を出射する。具体的に、光源１０１ａは波長“λ１”、光源１０１ｂは波長“λ２”、光源１０１ｃは波長“λ３”、光源１０１ｄは波長“λ４”の光を出射する。光源１０１ａ～１０１ｄとして、例えば半導体レーザが採用できる。 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 “λ1”, the light source 101b emits light of wavelength “λ2”, the light source 101c emits light of wavelength “λ3”, and the light source 101d emits light of wavelength “λ4”. As the light sources 101a to 101d, for example, semiconductor lasers can be employed.
　シャッタ１０６ａ～１０６ｄは、それぞれ対応する光源１０１ａ～１０１ｄから出射されるビーム光の光路上に設けられている。シャッタ１０６ａ～１０６ｄは、電圧が印加されることにより開口する。シャッタ１０６ａ～１０６ｄは、開いた状態の時にビーム光を透過し、閉じた状態の時にビーム光を遮断する（透過させない）。シャッタ１０６ａ～１０６ｄには、例えば、強誘電性液晶シャッタを用いる。 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. As the shutters 106a to 106d, for example, ferroelectric liquid crystal shutters are used.
　シャッタ１０６ａが開いた場合、シャッタ１０６ａを透過した波長“λ１”のビーム光は、図６Ａに示すように、光情報記録媒体２を介して対向する２方向のビーム光６０ａ，６１ａとなる。波長“λ１”のビーム光６０ａは、一方の対物レンズ１０９ａの中央位置に入射し、対物レンズ１０９ａを透過することにより収束光となって光情報記録媒体２に集光する。また、波長“λ１”のビーム光６１ａは、他方の対物レンズ１０９ａの中央位置に入射し、この位置から光情報記録媒体２の記録層２０２の記録位置に向けて集光する。光情報記録媒体２の記録層２０２の同一位置に波長“λ１”のビーム光６０ａ，６１ａが集光し、これらが互いに干渉することにより、波長“λ１”に対応する回折格子２０３ａが形成される。 When the shutter 106a is opened, the light beam having the wavelength “λ1” 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 “λ1” 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. Further, the beam light 61 a having the wavelength “λ1” 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 “λ1” 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 “λ1”. .
　同様に、シャッタ１０６ｂが開いた場合は、図６Ｂに示すように、波長“λ２”のビーム光６０ｂ，６１ｂが互いに干渉することにより、波長“λ２”に対応する回折格子２０３ｂが形成される。シャッタ１０６ｃが開いた場合は、図６Ｃに示すように、波長“λ３”のビーム光６０ｃ，６１ｃが互いに干渉することにより、波長“λ３”に対応する回折格子２０３ｃが形成される。シャッタ１０６ｄが開いた場合は、図６Ｄに示すように、波長“λ４”のビーム光６０ｄ，６１ｄが互いに干渉することにより、波長“λ４”に対応する回折格子２０３ｄが形成される。本実施形態では、波長λ１＝４００．５ｎｍ、波長λ２＝４０３．５ｎｍ、波長λ３＝４０６．５ｎｍ、波長λ４＝４０９．５ｎｍ、波長間隔Δλ＝３ｎｍのビーム光を光情報記録媒体２に入射する。ビーム光の波長λの値が大きいほど、記録位置に形成される回折格子の大きさは大きくなる。 Similarly, when the shutter 106b is opened, as shown in FIG. 6B, the light beams 60b and 61b having the wavelength “λ2” interfere with each other, thereby forming the diffraction grating 203b corresponding to the wavelength “λ2”. When the shutter 106c is opened, as shown in FIG. 6C, the light beams 60c and 61c having the wavelength “λ3” interfere with each other, thereby forming the diffraction grating 203c corresponding to the wavelength “λ3”. When the shutter 106d is opened, as shown in FIG. 6D, the light beams 60d and 61d having the wavelength “λ4” interfere with each other, thereby forming the diffraction grating 203d corresponding to the wavelength “λ4”. In the present embodiment, beam light having a wavelength λ1 = 400.5 nm, a wavelength λ2 = 403.5 nm, a wavelength λ3 = 406.5 nm, a wavelength λ4 = 409.5 nm, and a wavelength interval Δλ = 3 nm is incident on the optical information recording medium 2. . The larger the value of the wavelength λ of the light beam, the larger the size of the diffraction grating formed at the recording position.
　波長フィルタ１０３ａ～１０３ｃは、それぞれ対応するシャッタ１０６ａ～１０６ｄを透過するビーム光の光路上に設けられている。波長フィルタ１０３ｄ～１０３ｆは、光検出器１１０ａ～１１０ｄにビーム光が入射する光路上にそれぞれ設けられている。波長フィルタ１０３ａ～１０３ｆには、入射するビーム光の波長に応じて、ビーム光を透過又は反射させるビームスプリッタを用いる。 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. For the wavelength filters 103a to 103f, a beam splitter that transmits or reflects the beam light according to the wavelength of the incident beam light is used.
　具体的には、波長フィルタ１０３ａ，１０３ｄは、図５Ａに示すように、波長λ１の光を透過し、波長“λ２”～“λ４”の光を反射する。波長フィルタ１０３ｂ，１０３ｅは、図５Ｂに示すように、波長“λ１”～“λ３”の光を透過し、波長“λ４”の光を反射する。波長フィルタ１０３ｃ，１０３ｆは、図５Ｃに示すように、波長“λ１”，“λ２”の光を反射し、波長“λ３”，“λ４”の光を透過する。 Specifically, as shown in FIG. 5A, the wavelength filters 103a and 103d transmit light having a wavelength λ1, and reflect light having wavelengths “λ2” to “λ4”. As shown in FIG. 5B, the wavelength filters 103b and 103e transmit light having wavelengths “λ1” to “λ3” and reflect light having wavelength “λ4”. As shown in FIG. 5C, the wavelength filters 103c and 103f reflect light having wavelengths “λ1” and “λ2” and transmit light having wavelengths “λ3” and “λ4”.
　レンズ１０２ａ～１０２ｆは、それぞれ入射する光を、発散光から平行光又は平行光から収束光に変換する。なお、本実施形態において、レンズ１０２ａ～１０２ｅとして、図４に示すように、両面が凸形状の球面レンズを採用しているが、レンズの形状に限定はない。例えば、両面が凹形状の球面レンズ又は何れか一方の面が凸形状で他方の面が凹形状の球面レンズを用いても良く、また、非球面レンズを用いても良い。 The lenses 102a to 102f respectively convert incident light from divergent light into parallel light or from parallel light into convergent light. In this embodiment, as 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. 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.
　アクティブ波長板１０４は、レンズ１０２ａを透過するビーム光の光路上に設けられている。アクティブ波長板１０４は、電圧が印加されることにより動作し、印加される電圧に応じて１／４波長板としての機能と１／２波長板としての機能とが切り替わる。アクティブ波長板１０４は、一軸の屈折率異方性を有するネマティック液晶等の液晶層が２枚の基板に挟まれて構成されている。２枚の基板の液晶層と向かい合う面には、液晶層に交流電圧を印加するための透明電極が設けられている。 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.
　液晶層に所定の実効値（例えば２．５Ｖ）の交流電圧が印加されると、液晶層の光学軸の方向は、入射光の光軸に垂直な方向とその光軸に平行な方向との中間（波長４５°）の方向となる。この時、液晶層を透過する光に生じる光学軸と光軸とを含む面に平行な方向の偏光成分と垂直な方向との偏光成分との間の位相差はπ／２となり、アクティブ波長板１０４は１／４波長板として機能する。１／４波長板として機能するアクティブ波長板１０４は、入射した直線偏光を円偏光に変換する。 When an AC voltage having a predetermined effective value (for example, 2.5 V) is applied to 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 °). At this time, 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 π / 2, and 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.
　一方、液晶層に所定の実効値（例えば０Ｖ）の交流電圧が印加されると、液晶層の光学軸の方向は、入射光の光軸に垂直な方向となる。この時、液晶層を透過する光に生じる光学軸と光軸とを含む面に平行な方向の偏光成分と垂直な方向の偏光成分の間の位相差はπとなり、アクティブ波長板１０４は１／２波長板として機能する。１／２波長板として機能するアクティブ波長板１０４は、入射した直線偏光の偏光方向を９０度変化させる。 On the other hand, when an AC voltage having a predetermined effective value (for example, 0 V) is applied to the liquid crystal layer, the direction of the optical axis of the liquid crystal layer becomes a direction perpendicular to the optical axis of the incident light. At this time, 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 π, and 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.
　偏光ビームスプリッタ１０５は、アクティブ波長板１０４を透過するビーム光の光路上に設けられている。偏光ビームスプリッタ１０５は、入射面に平行なＰ偏光成分のビーム光を透過し、入射面に垂直なＳ偏光成分のビーム光を反射する。偏光ビームスプリッタ１０５は、アクティブ波長板１０４から入射されるビーム光の偏光成分に従って光路を第１の光路及び第２の光路に分岐させる。 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.
　ミラー１０７ａ～１０７ｄは、光路を変更し、前段の部材から入射されるビーム光を後段の部材に導くために配置される。 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.
　１／４波長板１０８ａ，１０８ｂは、入射するビーム光が直線偏光の場合、直線偏光を円偏光に変換し、また、入射するビーム光が円偏光の場合、円偏光を直線偏光に変換する。 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.
　対物レンズ１０９ａ，１０９ｂは、光情報記録媒体２を介して対向し、対物レンズ１０９ａが集光する第１の光路におけるビーム光と対物レンズ１０９ｂが集光する第２の光路におけるビーム光とが光情報記録媒体２の同一位置に集光されるように配置されている。なお、本実施形態において、対物レンズ１０９ａ，１０９ｂとして、図４に示すように、両面が凸形状の球面レンズを示しているが、レンズの形状に限定はない。例えば、両面が凹形状の球面レンズ又は何れか一方の面が凸形状で他方の面が凹形状の球面レンズを用いても良く、また、非球面レンズを用いても良い。 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. In the present embodiment, 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.
　光検出器１１０ａ～１１０ｄは、それぞれ波長フィルタ１０３ｄ～１０３ｆで透過又は反射されたビーム光の光路上に設けられている。光検出器１１０ａ～１１０ｄは、それぞれ対応する光源１０１ａ～１０１ｄから出射されたビーム光を受光する。光検出器１１０ａ～１１０ｄは、例えば、ＣＣＤ（Ｃｈａｒｇｅ　Ｃｏｕｐｌｅｄ　Ｄｅｖｉｃｅ）やＰＩＮフォトダイオード等の受光素子から構成される。 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.
　次に、光学ユニット駆動部１３の内部構成について説明する。光学ユニット駆動部１３は、図７に示すように、シャッタ駆動部２１と、アクティブ波長板駆動部２２と、光源駆動部２３と、受光信号取得部２４と、を備えている。 Next, the internal configuration of the optical unit driving unit 13 will be described. As shown in FIG. 7, 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.
　シャッタ駆動部２１は、シャッタ１０６ａ～１０６ｄを制御するためのシャッタ制御信号をコントローラ１１から受け取る。そして、シャッタ駆動部２１は、シャッタ１０６ａ～１０６ｄの内、当該シャッタ制御信号により示された開対象となっているシャッタに所定の電圧を印加する。 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.
　アクティブ波長板駆動部２２は、アクティブ波長板制御信号をコントローラ１１から受け取り、当該アクティブ波長板制御信号に従って、アクティブ波長板１０４に所定の電圧を印加する。具体的には、アクティブ波長板駆動部２２は、情報記録時に、所定の実効値の交流電圧（例えば２．５Ｖ）を印加することにより、アクティブ波長板１０４を１／４波長板として機能させる。また、情報再生時に、所定の実効値の交流電圧（例えば０Ｖ）を印加することにより、アクティブ波長板１０４を１／２波長板として機能させる。 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.
　光源駆動部２３は、光源１０１を制御するための光源制御信号をコントローラ１１から受け取り、当該光源制御信号に従って、光源１０１に一定の電流を供給する。 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.
　受光信号取得部２４は、情報再生時において、光検出した光検出器１１０ａ～１１０ｄから受光信号を受け取ることにより、光検出した光検出器１１０ａ～１１０ｄを特定し、特定した光検出器の情報を示す受光情報をコントローラ１１に供給する。 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.
　次に、本実施形態に係る光学的情報処理装置１の動作について説明する。光学的情報処理装置１の動作は、光情報記録媒体２に情報を記録する情報記録動作と、光情報記録媒体２に記録されている情報を再生する情報再生動作とに大別される。 Next, the operation of the optical information processing apparatus 1 according to this embodiment will be described. 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.
　まず、情報記録動作を説明する。情報記録時において、コントローラ１１は、操作部等を介して入力される情報記録を要求する記録要求信号と、図示しない記録データ入力部や記憶部等から供給される光情報記録媒体２に記録する記録データとを受け取り、これに応じてＲＯＭ等に記憶された情報記録プログラムを読み出し、これをＲＡＭ等に展開して実行する。 First, the information recording operation will be described. At the time of information recording, 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.
　具体的には、コントローラ１１が記録データ“１００００１１００１１０・・・”を受け取った場合、光情報記録媒体２の各記録位置に記録する情報のビット数が“２”なのでコントローラ１１は、“１０”、“００”、“０１”・・・、というように受け取った記録データを分割する。 Specifically, when 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”.
　つづいて、コントローラ１１は、分割した記録データに対応する波長制御データを波長制御データ記憶部１２から順次取得する。例えば、コントローラ１１は、“１０”に対応する“波長制御データ３”、“００”に対応する“波長制御データ１”、“０１”に対応する“波長制御データ２”・・・、というように波長制御データ記憶部１２から波長制御データを順次取得する。 Subsequently, the controller 11 sequentially acquires the wavelength control data corresponding to the divided recording data from the wavelength control data storage unit 12. For example, 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.
　さらに、コントローラ１１は、集光点移動機構１４０を駆動させるための移動制御信号を集光点移動機構駆動部１４に供給する。これに従って、集光点移動機構駆動部１４は、集光点移動機構１４０に動作用の駆動電圧等を印加する。集光点移動機構１４０は、集光点移動機構駆動部１４により印加される駆動電圧等により動作し、最初に情報が記録される位置（図３に示す記録層２０２の左上隅の位置）に集光点が位置するように制御する。また、集光点移動機構１４０は、光情報記録媒体２を回転させると共にトラックに集光点を追従させるトラッキング制御を行う。 Further, 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. In accordance with this, 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.
　以下、この場合において、最初に記録される光情報記録媒体２の記録位置に情報“１０”を記録する動作を説明する。 Hereinafter, the operation of recording information “10” at the recording position of the optical information recording medium 2 to be recorded first in this case will be described.
　コントローラ１１は、“１０”に対応する“波長制御データ３”が示すシャッタ情報３を基にシャッタ１０６ｃを制御するためのシャッタ制御信号をシャッタ駆動部２１に供給する。これに応じて、シャッタ駆動部２１は、シャッタ１０６ｃに電圧を印加してシャッタ１０６ｃを開口させる。 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.
　また、コントローラ１１は、アクティブ波長板１０４を１／４波長板として機能させるためのアクティブ波長板制御信号をアクティブ波長板駆動部２２に供給する。これに応じて、アクティブ波長板駆動部２２は、所定の実効値の交流電圧（例えば２．５Ｖ）を印加してアクティブ波長板１０４を１／４波長板として機能させる。 Further, 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. In response to this, 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.
　さらに、コントローラ１１は、光源１０１ａ～１０１ｄを制御するための光源制御信号を光源駆動部２３に供給する。これに応じて、光源駆動部２３は、光源１０１ａ～１０１ｄに一定の電流を供給して光源１０１ａ～１０１ｄを動作させる。 Furthermore, the controller 11 supplies a light source control signal for controlling the light sources 101a to 101d to the light source driving unit 23. In response to this, the light source driver 23 supplies a constant current to the light sources 101a to 101d to operate the light sources 101a to 101d.
　光源１０１ａは波長“λ１”、光源１０１ｂは波長“λ２”、光源１０１ｃは波長“λ３”、光源１０１ｄは波長“λ４”のビーム光（直線偏光）を出射する。光源１０１ａ～１０１ｄから出射されたビーム光は、それぞれの光路上に設けられたシャッタ１０６ａ～１０６ｄに入射する。 The light source 101a emits beam light (linearly polarized light) having a wavelength “λ1”, the light source 101b has a wavelength “λ2”, the light source 101c has a wavelength “λ3”, and the light source 101d has a wavelength “λ4”. The light beams emitted from the light sources 101a to 101d are incident on shutters 106a to 106d provided on the respective optical paths.
　シャッタ１０６ａ～１０６ｄに入射した４つの波長のビーム光は、開いた状態のシャッタ１０６ｃを透過し、その他のシャッタ１０６ａ，１０６ｂ，１０６ｄを透過しない。 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.
　シャッタ１０６ｃを透過した波長“λ３”のビーム光は、波長フィルタ１０３ｃ，１０３ｂを透過し、レンズ１０２ａにより平行化され、１／４波長板として機能しているアクティブ波長板１０４により直線偏光から円偏光に変換された後、偏光ビームスプリッタ１０５に入射する。 The light beam having the wavelength “λ3” 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.
　偏光ビームスプリッタ１０５に入射した円偏光のうちＳ偏光成分のビーム光６０ｃ（入射光の約５０％）は、偏光ビームスプリッタ１０５で反射される。ビーム光６０ｃはレンズ１０２ｂ、ミラー１０７ａ、レンズ１０２ｃ、ミラー１０７ｂ、１／４波長板１０８ａを介して、図６Ｃに示すように、対物レンズ１０９ａの中央位置に入射する。そして、ビーム光６０ｃは、対物レンズ１０９ａを透過することにより収束光となって光情報記録媒体２の記録層２０２の記録位置（情報が最初に記録される位置）に集光される。 Of the circularly polarized light incident on the polarizing 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. As shown in FIG. 6C, 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.
　一方、偏光ビームスプリッタ１０５に入射した円偏光のうちＰ偏光成分のビーム光６１ｃ（入射光の約５０％）は、偏光ビームスプリッタ１０５を透過する。ビーム光６１ｃは、レンズ１０２ｄ、ミラー１０７ｃ、レンズ１０２ｅ、ミラー１０７ｄ、１／４波長板１０８ｂを介して、図６Ｃに示すように、対物レンズ１０９ｂの中央位置に入射する。そして、ビーム光６１ｃは、対物レンズ１０９ｂを透過することにより収束光となって光情報記録媒体２の記録層２０２の記録位置（情報が最初に記録される位置）に集光される。 On the other hand, 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.
　したがって、光情報記録媒体２の記録層２０２の記録位置には、互いに対向する２つの波長“λ３”のビーム光６０ｃ，６１ｃが光情報記録媒体２に集光される。そして、この記録位置においてビーム光６０ｃ，６１ｃが互いに干渉することにより波長“λ３”に対応する回折格子２０３ｃが形成される。これにより、情報が最初に記録される光情報記録媒体２の記録位置に、コントローラ１１が分割した記録データの最初の記録データ“１０”に対応する情報記録が行われる。 Therefore, the two light beams 60 c and 61 c having the wavelength “λ3” 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 “λ3” 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.
　その後、光情報記録媒体２の記録位置に次の情報を記録するため、コントローラ１１は、集光点移動機構１４０を駆動させるための移動制御信号を集光点移動機構駆動部１４に供給する。これに従って、集光点移動機構駆動部１４は、集光点移動機構１４０に対して、駆動電圧等を印加する。集光点移動機構１４０は、集光点移動機構駆動部１４により印加される駆動電圧等により動作し、次に情報が記録される位置（図３に示す記録層２０２の左上隅の位置）に集光点が位置するように制御する。また、集光点移動機構１４０は、光情報記録媒体２を回転させると共にトラックに集光点を追従させるトラッキング制御を行う。 Thereafter, in order to record the next information at the recording position of the optical information recording medium 2, 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. 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 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.
　そして、コントローラ１１が取得した、分割した残りの記録データ（“００”、“０１”、“１０”、“０１”、“１０”・・・）に対応する波長制御データ（“波長制御データ１”、“波長制御データ２”、“波長制御データ３”、“波長制御データ２”、“波長制御データ３”・・・）に基づいて、上記と同様の動作が、繰り返し行われる。これにより、光情報記録媒体２の各記録位置には、順次、波長“λ１”、波長“λ２”、波長“λ３”、波長“λ２”、波長“λ３”のビーム光が集光され、それぞれのビーム光の波長に対応する回折格子が順次形成されていく。 Then, the wavelength control data (“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 ”... As a result, the light beams having the wavelength “λ1”, the wavelength “λ2”, the wavelength “λ3”, the wavelength “λ2”, and the wavelength “λ3” 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.
　以上の情報記録動作により、記録データ（“１００００１１００１１０・・・”）を光情報記録媒体２に記録することができる。 Through the above information recording operation, recording data (“10000100100 ......”) Can be recorded on the optical information recording medium 2.
　次に、情報再生動作を説明する。情報再生時において、コントローラ１１は、操作部等を介して入力される情報再生を要求する再生要求信号を受け取り、これに応じてＲＯＭ等に記憶された情報再生プログラムを読み出し、これをＲＡＭ等に展開して実行する。 Next, the information reproduction operation will be described. At the time of information reproduction, 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.
　具体的には、コントローラ１１は、情報記録時において記録した記録データ（“１００００１１００１１０・・・”）の再生要求に従い、波長制御データ記憶部１２に記憶された全ての波長制御データ（波長制御データ１～４）を取得する。 Specifically, 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).
　また、コントローラ１１は、集光点移動機構１４０を動作させるための移動制御信号を集光点移動機構駆動部１４に供給する。これに従って、集光点移動機構駆動部１４は、集光点移動機構１４０に対して、駆動電圧等を印加する。集光点移動機構１４０は、集光点移動機構駆動部１４により印加される駆動電圧等により動作し、最初の情報を再生する位置（図３に示す記録層２０２の左上隅の位置）に集光点が位置するように制御する。また、集光点移動機構１４０は、光情報記録媒体２を回転させると共にトラックに集光点を追従させるトラッキング制御を行う。 Further, 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.
　以下、この場合において、光情報記録媒体２の記録位置に最初に記録した情報を再生する動作を説明する。 Hereinafter, in this case, an operation of reproducing the information recorded at the recording position of the optical information recording medium 2 will be described.
　コントローラ１１は、“波長制御データ１”、“波長制御データ２”、“波長制御データ３”、“波長制御データ４”が示す各シャッタ情報を基に、全てのシャッタ１０６ａ～１０６ｄを動作させるためのシャッタ制御信号をシャッタ駆動部２１に供給する。これに応じて、シャッタ駆動部２１は、シャッタ１０６ａ～１０６ｄに電圧を印加してシャッタ１０６ａ～１０６ｄを開く。 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. In response to this, the shutter drive unit 21 applies a voltage to the shutters 106a to 106d to open the shutters 106a to 106d.
　また、コントローラ１１は、アクティブ波長板１０４を１／２波長板として機能させるためのアクティブ波長板制御信号をアクティブ波長板駆動部２２に供給する。これに応じて、アクティブ波長板駆動部２２は、所定の実効値の交流電圧（例えば０Ｖ）をアクティブ波長板１０４に印加してアクティブ波長板１０４を１／２波長板として機能させる。 Further, 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. In response to this, 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.
　さらに、コントローラ１１は、光源１０１ａ～１０１ｄを動作させるための光源制御信号を光源駆動部２３に供給する。これに応じて、光源駆動部２３は、光源１０１ａ～１０１ｄに一定の電流を供給して光源１０１ａ～１０１ｄを動作させる。 Furthermore, the controller 11 supplies a light source control signal for operating the light sources 101a to 101d to the light source driving unit 23. In response to this, the light source driver 23 supplies a constant current to the light sources 101a to 101d to operate the light sources 101a to 101d.
　光源１０１ａは波長“λ１”、光源１０１ｂは波長“λ２”、光源１０１ｃは波長“λ３”、光源１０１ｄは波長“λ４”のビーム光をそれぞれ出射する。光源１０１ａ～１０１ｄから出射された各ビーム光は、それぞれ対応するシャッタ１０６ａ～１０６ｄに入射する。 The light source 101a emits a light beam having a wavelength “λ1”, the light source 101b emits a light beam having a wavelength “λ2”, the light source 101c emits a light beam having a wavelength “λ3”, and the light source 101d emits a light beam having a wavelength “λ4”. The light beams emitted from the light sources 101a to 101d are incident on the corresponding shutters 106a to 106d.
　シャッタ１０６ａ～１０６ｄは、全て開いた状態であり、シャッタ１０６ａ～１０６ｄに入射したそれぞれのビーム光は、シャッタ１０６ａ～１０６ｄを透過する。 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.
　シャッタ１０６ａを透過した波長“λ１”のビーム光は、波長フィルタ１０３ａを透過し、波長フィルタ１０３ｂで反射される。シャッタ１０６ｂを透過した波長“λ２”のビーム光は、波長フィルタ１０３ａ，１０３ｂで反射される。シャッタ１０６ｃを透過した波長“λ３”のビーム光は、波長フィルタ１０３ｃ，１０３ｂを透過する。シャッタ１０６ｄを透過した波長“λ４”のビーム光は、波長フィルタ１０３ｃで反射され、波長フィルタ１０３ｂを透過する。 The light beam having the wavelength “λ1” 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 “λ2” transmitted through the shutter 106b is reflected by the wavelength filters 103a and 103b. The light beam having the wavelength “λ3” transmitted through the shutter 106c is transmitted through the wavelength filters 103c and 103b. The light beam having the wavelength “λ4” transmitted through the shutter 106d is reflected by the wavelength filter 103c and passes through the wavelength filter 103b.
　したがって、光源１０１ａ～１０１ｄから出射したそれぞれ異なる波長（λ１～λ４）を有する４つのビーム光は、全てレンズ１０２ａに入射する。そして、レンズ１０２ａにより平行化され、１／２波長板として機能しているアクティブ波長板１０４により直線偏光の偏光方向が９０度変化された後、偏光ビームスプリッタ１０５に入射する。 Therefore, all four light beams having different wavelengths (λ1 to λ4) emitted from the light sources 101a to 101d are incident on the lens 102a. Then, the polarization direction of the linearly polarized light is changed by 90 degrees by the active wavelength plate 104 that is collimated by the lens 102 a and functions as a half-wave plate, and then enters the polarization beam splitter 105.
　偏光ビームスプリッタ１０５に入射した約１００％のビーム光であるＳ偏光成分のビーム光７０ａ～７０ｄは、偏光ビームスプリッタ１０５で反射される。そして、レンズ１０２ｂ、ミラー１０７ａ、レンズ１０２ｃ、ミラー１０７ｂ、１／４波長板１０８ａ、対物レンズ１０９ａを介して、光情報記録媒体２の記録層２０２の記録位置（情報が最初に記録される位置）に集光される。 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.
　したがって、情報再生時においては、図８Ａ～図８Ｄにそれぞれ示すように、波長“λ１”～“λ４”のビーム光が一方の面側（対物レンズ１０９ａ側）から光情報記録媒体２の記録層２０２の記録位置に集光する。 Accordingly, at the time of information reproduction, as shown in FIGS. 8A to 8D, the light beams of wavelengths “λ1” to “λ4” 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.
　そして、この記録位置において、情報記録時で用いたビーム光と同じ波長のビーム光のみが、情報記録時に形成した回折格子で反射される。一方、情報記録時と異なる波長のビーム光が集光した場合や、当該記録位置に回折格子が形成されていない場合、当該ビーム光は当該記録位置を透過する。 At this recording position, only the light beam having the same wavelength as that used for information recording is reflected by the diffraction grating formed during information recording. On the other hand, when the light beam having a wavelength different from that at the time of information recording is condensed, or when the diffraction grating is not formed at the recording position, the beam light is transmitted through the recording position.
　本実施形態では、光情報記録媒体２の記録層２０２の情報が最初に記録される記録位置に、波長“λ３”のビーム光６０ｃ，６１ｃにより回折格子２０３ｃが形成されているの。したがって、図８Ｃに示すように、波長“λ３”のビーム光７０ｃのみが、回折格子２０３ｃで反射され、それ以外の波長“λ１”，“λ２”，“λ４”のビーム光７０ａ，７０ｂ，７０ｄは、当該記録位置を透過する。 In this embodiment, the diffraction grating 203c is formed by the light beams 60c and 61c having the wavelength “λ3” 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 “λ3” is reflected by the diffraction grating 203c, and the other light beams 70a, 70b, and 70d having the wavelengths “λ1”, “λ2”, and “λ4” are reflected. Passes through the recording position.
　回折格子２０３ｃで反射された反射ビーム光７０ｃ’は、上記の方向とは逆向きに対物レンズ１０９ａ、１／４波長板１０８ａ、ミラー１０７ｂ、レンズ１０２ｃ、ミラー１０７ａ、レンズ１０２ｂを介して、偏光ビームスプリッタ１０５に入射する。 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.
　偏光ビームスプリッタ１０５に入射した約１００％のビーム光であるＰ偏光成分のビーム光は、偏光ビームスプリッタ１０５を透過する。偏光ビームスプリッタ１０５を透過した波長“λ３”のビーム光は、波長フィルタ１０３ｆ，１０３ｅを透過し、光検出器１１０ｃで受光される。 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 “λ3” that has passed through the polarization beam splitter 105 passes through the wavelength filters 103f and 103e and is received by the photodetector 110c.
　ビーム光を受光した光検出器１１０ｃは、光学ユニット駆動部１３の受光信号取得部２４に受光信号を供給する。受光信号取得部２４は、受光信号を受け取ることにより反射ビーム光７０ｃ’を検出した光検出器１１０ｃを特定し、特定した光検出器１１０ｃを示した受光情報（受光情報３）をコントローラ１１に供給する。 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.
　これに応じてコントローラ１１は、受光情報３に対応する“波長制御データ３”を波長制御データ記憶部１２から取得し、当該“波長制御データ３”に対応付けられた情報“１０”を取得する。これにより、光情報記録媒体２の記録位置に記録した最初の情報“１０”の再生が行われる。 In response to this, 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”. . As a result, the first information “10” recorded at the recording position of the optical information recording medium 2 is reproduced.
　その後、光情報記録媒体２の記録位置から次の情報を再生するため、コントローラ１１は、集光点移動機構駆動部１４を駆動させるための移動制御信号を集光点移動機構駆動部１４に供給する。これに従って、集光点移動機構駆動部１４は、集光点移動機構１４０に対して、駆動電圧等を印加する。集光点移動機構１４０は、集光点移動機構駆動部１４により印加される駆動電圧等により動作し、次の情報を再生する位置（図３に示す記録層２０２の左上隅の位置）に集光点が位置するように制御する。また、集光点移動機構１４０は、光情報記録媒体２を回転させると共にトラックに集光点を追従させるトラッキング制御を行う。 Thereafter, in order to reproduce the next information from the recording position of the optical information recording medium 2, 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. To do. 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 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.
　そして、上記と同様の動作を繰り返し行うことにより、コントローラ１１は、順次、“波長制御データ１”に対応付けられた情報“００”、“波長制御データ２”に対応付けられた情報“０１”、“波長制御データ３”に対応付けられた情報“１０”・・・、というように、順次取得される波長制御データに対応付けられた２ビットの情報を取得していく。 Then, by repeatedly performing the same operation as described above, 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.
　以上の情報再生動作により、情報記録時において記録した記録データ（“１００００１１００１１０・・・”）を再生することができる。 By the above information reproducing operation, the recorded data (“100001100110...”) Recorded at the time of information recording can be reproduced.
　以上、本実施形態の光学的情報処理装置１によれば、記録情報（“００”，“０１”，“１０”，“１１”）毎に割り当てた波長（“λ１”，“λ２”，“λ３”，“λ４”）のビーム光を用いて集光する制御を行い、各記録位置に１個の回折格子を形成することにより、２ビットの情報記録再生を行うことができる。この場合、光情報記録媒体２の記録層２０２の屈折率変化の最大値をΔｎとすると、１個の回折格子に割り当てられる屈折率変化はΔｎとなる。これに対し、従来のように、２ビットの情報記録再生を、１個の回折格子を形成するか否かにより行う場合、最大で２個の回折格子を記録位置に形成する必要がある。この時、１個の回折格子に割り当てられる屈折率変化はΔｎ／２である。また、１個の回折格子の回折効率は屈折率変化の２乗に比例する。したがって、本実施形態の光学的情報処理装置１は、従来と比べて、回折格子の回折効率を４倍に高めることができる。このように、本実施形態の光学的情報処理装置１によれば、各記録位置に形成できる回折格子の数が制限されている中で、より多くの情報の記録再生を行うことができる。 As described above, according to the optical information processing apparatus 1 of the present embodiment, the wavelengths (“λ1”, “λ2”, “λ”) assigned to the recording information (“00”, “01”, “10”, “11”). 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. In this case, assuming that the maximum value of the refractive index change of the recording layer 202 of the optical information recording medium 2 is Δn, the refractive index change assigned to one diffraction grating is Δn. On the other hand, when performing 2-bit information recording / reproduction according to whether or not to form one diffraction grating as in the prior art, it is necessary to form a maximum of two diffraction gratings at the recording position. At this time, the refractive index change assigned to one diffraction grating is Δn / 2. Further, the diffraction efficiency of one diffraction grating is proportional to the square of the refractive index change. Therefore, 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.
　なお、光情報記録媒体２に集光するビーム光の波長の間隔（Δλ）は、再生すべき回折格子から受け取る信号レベルに対する、他の回折格子から受け取る信号レベルの比であるクロストークの影響を受けないようにしなければならない。つまり、再生対象となっている回折格子以外の回折格子からの反射ビーム光を受光しないようにしなければならない。 Note that the wavelength interval (Δλ) 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.
　対物レンズ１０９ａ，１０９ｂを介して光情報記録媒体２の記録層２０２に集光するビーム光の光軸方向の大きさは、記録再生に用いる光の波長をλ、対物レンズ１０９ａ、１０９ｂの開口数をＮＡ、記録層２０２の屈折率をｎ０とすると、４ｎ０λ／ＮＡ２で与えられる。従って、記録層２０２に形成される回折格子２０３の光軸方向の大きさも、ほぼ４ｎ０λ／ＮＡ２となる。光情報記録媒体２に集光するビーム光の波長を変化させた場合の回折格子の回折効率（反射率）は、結合波理論により求められる。  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 λ for the wavelength of light used for recording and reproduction, and the numerical apertures of the objective lenses 109a and 109b. Is NA, and the refractive index of the recording layer 202 is n 0 , 4n 0 λ / NA 2 is given. Therefore, the size of the diffraction grating 203 formed in the recording layer 202 in the optical axis direction is also approximately 4n 0 λ / NA 2 . 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.
　図９を用いて、情報再生時に光情報記録媒体２に集光するビーム光と回折格子の回折効率との関係（記録波長と再生波長との関係）について説明する。光情報記録媒体２への情報記録時において、記録に用いる光の光情報記録媒体２への波長は、λ１＝４００．５ｎｍ、λ２＝４０３．５ｎｍ、λ３＝４０６．５ｎｍ、λ４＝４０９．５ｎｍとし、波長の間隔はΔλ＝３ｎｍとした。 Referring to FIG. 9, 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. When recording information on the optical information recording medium 2, the wavelengths of light used for recording on the optical information recording medium 2 are λ1 = 400.5 nm, λ2 = 403.5 nm, λ3 = 406.5 nm, and λ4 = 409.5 nm. And the wavelength interval was Δλ = 3 nm.
　また、情報再生時には、光情報記録媒体２に集光するビーム光の波長をλ＝３９９ｎｍ～４１１ｎｍの範囲で変化させた。図９において横軸は再生波長を示し、縦軸は回折格子の回折効率を再生波長が記録波長と一致しているときの値で規格化した信号レベルを示す。また、図９では、記録波長が“λ１”～“λ４”の場合に得られた４つの曲線を重ねて示している。記録波長が“λ１”～“λ４”の何れである場合も、再生波長が記録波長と一致しているときの信号レベルは１である。しかし、再生波長が記録波長から離れるに従って信号レベルは小さくなり、再生波長が記録波長からΔλだけ離れているときの信号レベルはほぼ０となる。この場合、再生対象となっている回折格子以外の回折格子からの反射ビーム光は受光されない。 Further, at the time of information reproduction, the wavelength of the beam light condensed on the optical information recording medium 2 was changed in the range of λ = 399 nm to 411 nm. In FIG. 9, the horizontal axis represents the reproduction wavelength, and 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. In FIG. 9, four curves obtained when the recording wavelengths are “λ1” to “λ4” are superimposed. In any of the recording wavelengths “λ1” to “λ4”, the signal level is 1 when the reproduction wavelength matches the recording wavelength. However, 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 Δλ. In this case, reflected beam light from a diffraction grating other than the diffraction grating to be reproduced is not received.
　例えば、情報記録時に波長λ１の条件で形成された回折格子において、情報再生時に波長λ１の条件で集光した場合の受光信号レベルは１であり、波長λ２，λ３，λ４の条件で集光した場合の信号レベルはほぼ０である。つまり、再生対象となっている回折格子以外の回折格子からの反射ビーム光は受光されず、クロストークの影響を受けないことが判る。 For example, in a diffraction grating formed under the condition of wavelength λ1 at the time of information recording, the light reception signal level when the light is condensed under the condition of wavelength λ1 during information reproduction is 1, and the light is collected under the conditions of wavelengths λ2, λ3, and λ4. 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.
　また、本実施形態では、光情報記録媒体２の各記録位置において２ビットの情報記録再生を行う態様について説明したが、本発明は、２ビットの情報の記録再生に限定されない。光情報記録媒体２に記録する情報と光情報記録媒体２に集光するビーム光の波長とについて、下記の条件を満たせば、記録され得るビット数は任意である。
　２ｄ≦ｐＣｑ
　ｄ；光情報記録媒体２の各記録位置に記録する情報のビット数
　２ｄ；情報数
　ｐ；光情報記録媒体２の各記録位置に集光可能なビーム光の波長の設定数
　ｑ；集光可能なビーム光から選択するビーム光の波長の設定数 In the present embodiment, 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. However, 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
　波長制御データ記憶部１２は、複数ビットの情報毎に、ビーム光の波長を制御する波長制御データを対応付けて記憶している。 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.
　なお、回折格子を形成した時の屈折率変化や回折効率を考慮すると、光情報記録媒体２の各記録位置に形成される回折格子の数は少ない方が良い。したがって、選択するビーム光の数は少ない方が良い。例えば、２ビットの記録情報を４つの波長（“λ１”～“λ４”）を用いて表現する場合、４つの波長から２つの波長を選択するよりも、１つの波長を選択した方が良い。そうすることで、１個の回折格子が形成され、２個の回折格子が形成される時よりも屈折率変化が小さく、また、回折効率も低下しない。 In consideration of the refractive index change and diffraction efficiency when the diffraction grating is formed, it is better that 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 (“λ1” to “λ4”), 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.
　さらに、本実施の形態では、光情報記録媒体２に集光するビーム光を、シャッタ１０６ａ～１０６ｄを用いて選択する構成としたが、かかる構成に限定されない。例えば、シャッタ１０６ａ～１０６ｄを用いずに、光源１０１ａ～１０１ｄから出射するビーム光を選択する構成としても良い。この場合、波長制御データには、シャッタ情報の代わりに、光源１０１ａ～１０１ｄの何れを駆動対象とするかを示す光源情報が含まれる。かかる構成にすることで、コントローラ１１は、駆動対象となる光源を制御するための光源制御信号を光源駆動部２３に供給すれば良く、シャッタ駆動部２１は不要になり、部品点数を削減できる。 Furthermore, in this embodiment, 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. For example, 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. In this case, 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. With this configuration, 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.
　また、本実施形態では、それぞれ異なる波長のビーム光を出射する複数の光源１０１ａ～１０１ｄを用いる構成としたが、図１０に示すように、異なる波長のビーム光が出射可能な一台の波長可変光源１０１’を用いる構成としても良い。この場合、波長制御データには、波長可変光源１０１’に出射させる光の波長を示す波長情報が含まれる。かかる構成により、部品点数の削減が図れる。この場合、例えば、記録情報（例えば“００”）に対応する波長（この場合“λ１”）のビーム光を出射させるための光源制御信号を波長可変光源１０１’に供給する。そして、これに応じて波長可変光源１０１’が波長“λ１”のビーム光を出射することにより、光情報記録媒体２の記録層２０２の記録位置に回折格子２０３ａが形成される。 In this embodiment, a plurality of light sources 101a to 101d that emit light beams having different wavelengths are used. However, as shown in FIG. 10, a single variable wavelength unit that can emit light beams having different wavelengths is used. A configuration using the light source 101 ′ may be used. In this case, the wavelength control data includes wavelength information indicating the wavelength of light emitted from the wavelength tunable light source 101 ′. With this configuration, the number of parts can be reduced. In this case, for example, a light source control signal for emitting beam light having a wavelength (in this case, “λ1”) corresponding to recording information (for example, “00”) is supplied to the wavelength variable light source 101 ′. In response to this, the wavelength tunable light source 101 ′ emits beam light having a wavelength “λ1”, whereby a diffraction grating 203 a is formed at the recording position of the recording layer 202 of the optical information recording medium 2.
　なお、上記の場合、情報再生時においてビーム光を受光する光検出器１１０’も一台で足りる。つまり、情報再生時に、波長可変光源１０１’から全ての波長制御データに対応する波長“λ１”～“λ４”のビーム光を順次出射する。そして、その度に、コントローラ１１が光検出器１１０’から供給される受光信号の有無を判定する。これにより、ビーム光を受光した時の波長（例えば、“λ１”）を特定し、特定した受光情報（例えば、受光情報１）に対応する情報（例えば、“００”）を再生することができる。 In the above case, 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 “λ1” to “λ4” 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, “λ1”) 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. .
　また、光学的情報処理装置１が、記録時において、要求された記録データのデータサイズと、光情報記録媒体２のメモリ容量とに基づいて、光情報記録媒体２に集光可能なビーム光から選択するビーム光の数（ｑ）及びビット数（ｄ）を決定するようにしてもよい。例えば、光情報記録媒体２に集光可能なビーム光の数（ｐ）が、５種類（波長“λ１”～“λ５”）あり、光情報記録媒体２の残りの記録位置が６０箇所あった場合を想定する。ここで、データサイズが１００ビットの記録データの記録を要求された際、光学的情報処理装置１（コントローラ１１）は、各記録位置に記録する情報のビット数（ｄ）を２ビットと決定し、光情報記録媒体２に集光可能なビーム光から選択するビーム光の数（ｑ）をｑ＝１と決定する。 Further, 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. For example, the number (p) of light beams that can be focused on the optical information recording medium 2 is five (wavelengths “λ1” to “λ5”), and there are 60 remaining recording positions on the optical information recording medium 2. Assume a case. Here, when recording of recording data having a data size of 100 bits is requested, the optical information processing apparatus 1 (controller 11) determines the number of bits (d) of information to be recorded at each recording position as 2 bits. The number (q) of light beams to be selected from the light beams that can be condensed on the optical information recording medium 2 is determined as q = 1.
　つまり、この場合は、光情報記録媒体２に集光可能なビーム光の波長“λ１”～“λ５”から１種類の波長を選択すること（２２≦５Ｃ１）により、上記記録データを記録することができる。一方、上記の場合において、データサイズが１５０ビットの記録データの記録を要求された際、光学的情報処理装置１（コントローラ１１）は、各記録位置に記録する情報のビット数（ｄ）を３ビットと決定し、光情報記録媒体２に集光可能なビーム光から選択するビーム光の数（ｑ）をｑ＝２と決定する。つまり、この場合は、光情報記録媒体２に集光可能なビーム光の波長“λ１”～“λ５”から２種類の波長を選択すること（２３≦５Ｃ２）により、上記記録データを記録することができる。 That is, in this case, by selecting one type of wavelength from the wavelengths “λ1” to “λ5” of the beam light that can be collected on the optical information recording medium 2 (2 2 ≦ 5 C 1 ), Can be recorded. On the other hand, in the above case, when recording of recording data having a data size of 150 bits is requested, the optical information processing apparatus 1 (controller 11) sets the number of bits (d) of information to be recorded at each recording position to 3 The number of light beams (q) selected from the light beams that can be collected on the optical information recording medium 2 is determined as q = 2. That is, in this case, by selecting two types of wavelengths (2 3 ≦ 5 C 2 ) from the wavelengths “λ1” to “λ5” of the beam light that can be collected on the optical information recording medium 2, Can be recorded.
　本発明は、上記実施形態に限定されず、本発明の要旨を逸脱しない範囲での種々の変更は勿論可能である。 The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.
　なお、本出願は、２００９年１２月２８日に出願された日本国特許出願特願２００９－２９８８５６号に基づく。本明細書中に、その明細書、特許請求の範囲、図面全体を参照して取り込むものとする。 This application is based on Japanese Patent Application No. 2009-298856 filed on Dec. 28, 2009. The specification, claims, and entire drawings are incorporated in this specification.
　１　　光学的情報処理装置
　２　　光情報記録媒体
　１１　コントローラ
　１２　波長制御データ記憶部
　１３　光学ユニット駆動部
　１４　集光点移動機構駆動部
　２１　シャッタ駆動部
　２２　アクティブ波長板駆動部
　２３　光源駆動部
　２４　受光信号取得部
　６０ａ，６０ｂ，６０ｃ，６０ｄ　ビーム光
　６１ａ，６１ｂ，６１ｃ，６１ｄ　ビーム光
　７０ａ，７０ｂ，７０ｃ，７０ｄ　ビーム光
　７０ｃ’反射ビーム光
　１００　光学ユニット
　１０１ａ，１０１ｂ，１０１ｃ，１０１ｄ　光源
　１０１’波長可変光源
　１０２ａ，１０２ｂ，１０２ｃ，１０２ｄ，１０２ｅ，１０２ｆ　レンズ
　１０３ａ，１０３ｂ，１０３ｃ，１０３ｄ，１０３ｅ，１０３ｆ　波長フィルタ
　１０４　アクティブ波長板
　１０５　偏光ビームスプリッタ
　１０６ａ，１０６ｂ，１０６ｃ，１０６ｄ　シャッタ
　１０７ａ，１０７ｂ，１０７ｃ，１０７ｄ　ミラー
　１０８ａ，１０８ｂ　１／４波長板
　１０９ａ，１０９ｂ　対物レンズ
　１１０ａ，１１０ｂ，１１０ｃ，１１０ｄ，１１０’　光検出器
　１４０　集光点移動機構
　２０１ａ，２０１ｂ　基板
　２０２　記録層
　２０３，２０３ａ，２０３ｂ，２０３ｃ，２０３ｄ　回折格子 DESCRIPTION OF SYMBOLS 1 Optical information processing apparatus 2 Optical information recording medium 11 Controller 12 Wavelength control data memory | storage part 13 Optical unit drive part 14 Condensing point moving mechanism drive part 21 Shutter drive part 22 Active wavelength plate drive part 23 Light source drive part 24 Light reception signal acquisition Units 60a, 60b, 60c, 60d Beam light 61a, 61b, 61c, 61d Beam light 70a, 70b, 70c, 70d Beam light 70c 'Reflected beam light 100 Optical unit 101a, 101b, 101c, 101d Light source 101' Wavelength variable light source 102a , 102b, 102c, 102d, 102e, 102f Lens 103a, 103b, 103c, 103d, 103e, 103f Wavelength filter 104 Active wavelength plate 105 Polarizing beam splitter 106a, 106b, 106c, 106d Shutter 107a, 107b, 107c, 107d Mirrors 108a, 108b 1/4 wavelength plates 109a, 109b Objective lenses 110a, 110b, 110c, 110d, 110 ′ Photo detector 140 Condensing point moving mechanism 201a, 201b Substrate 202 Recording layer 203, 203a , 203b, 203c, 203d diffraction grating

Claims (9)

  1. 　光情報記録媒体に対して、情報の記録及び再生の少なくとも何れか一方を行う光学的情報処理装置であって、
    　前記光情報記録媒体に記録され得る記録情報毎に、前記光情報記録媒体に集光するビーム光の波長を制御するための情報を示す波長制御データを対応付けて記憶した波長制御データ記憶手段と、
    　情報の記録又は再生の際、前記波長制御データ記憶手段から１又は複数の前記波長制御データを取得し、取得した１又は複数の波長制御データに基づいて、前記光情報記録媒体に集光するビーム光の波長を制御する制御手段と、を備える、
    　ことを特徴とする光学的情報処理装置。     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 more wavelength control data from the wavelength control data storage means, and focuses on the optical information recording medium based on the acquired one or more wavelength control data Control means for controlling the wavelength of light,
    An optical information processing apparatus.
  2. 　前記制御手段は、
    　前記光情報記録媒体に情報を記録する場合には、前記波長制御データ記憶手段から当該情報に対応する前記波長制御データを取得し、
    　前記光情報記録媒体から情報を再生する場合には、前記波長制御データ記憶手段から全ての前記波長制御データを取得する、
    　ことを特徴とする請求項１に記載の光学的情報処理装置。     The control means includes
    When recording information on the optical information recording medium, obtain the wavelength control data corresponding to the information from the wavelength control data storage means,
    When reproducing information from the optical information recording medium, obtain all the wavelength control data from the wavelength control data storage means,
    The optical information processing apparatus according to claim 1.
  3. 　前記光情報記録媒体に記録する情報と前記光情報記録媒体に集光するビーム光の波長との関係が、以下の条件
    　２ｄ≦ｐＣｑ
    　ｄ；光情報記録媒体に記録する情報のビット数
    　ｐ；光情報記録媒体に集光可能なビーム光の波長の設定数
    　ｑ；選択するビーム光の波長の設定数
    を満たしている、
    　ことを特徴とする請求項１又は２に記載の光学的情報処理装置。     The relationship between the information recorded on the optical information recording medium and the wavelength of the beam light condensed on the optical information recording medium is as follows: 2 d ≦ p C q
    d: the number of bits of information to be recorded on the optical information recording medium p: the set number of wavelengths of the beam light that can be collected on the optical information recording medium q: the set number of wavelengths of the light beam to be selected is satisfied,
    The optical information processing apparatus according to claim 1 or 2.
  4. 　前記波長制御データは、前記光情報記録媒体に集光するビーム光の波長を制御するシャッタを動作させるためのシャッタ情報を有し、
    　前記制御手段は、前記シャッタ情報を用いて前記光情報記録媒体に集光するビーム光の波長を制御する、
    　ことを特徴とする請求項１乃至３の何れか１項に記載の光学的情報処理装置。     The wavelength control data includes shutter information for operating a shutter that controls the wavelength of the light beam condensed on the optical information recording medium,
    The control means controls the wavelength of the light beam condensed on the optical information recording medium using the shutter information;
    The optical information processing apparatus according to claim 1, wherein the optical information processing apparatus is an optical information processing apparatus.
  5. 　前記波長制御データは、それぞれが異なる波長の光を出射する複数の光源の内の何れを駆動対象にするかを示す光源情報を有し、
    　前記制御手段は、前記光源情報を用いて前記光情報記録媒体に集光するビーム光の波長を制御する、
    　ことを特徴とする請求項１乃至３の何れか１項に記載の光学的情報処理装置。     The wavelength control data includes light source information indicating which of a plurality of light sources that emit light of different wavelengths is to be driven,
    The control means controls the wavelength of the light beam condensed on the optical information recording medium using the light source information.
    The optical information processing apparatus according to claim 1, wherein the optical information processing apparatus is an optical information processing apparatus.
  6. 　前記波長制御データは、異なる波長の光を出射する波長可変光源に対して、何れの波長の光を出射させるかを示す波長情報を有し、
    　前記制御手段は、前記波長情報を用いて前記光情報記録媒体に集光するビーム光の波長を制御する、
    　ことを特徴とする請求項１乃至３の何れか１項に記載の光学的情報処理装置。     The wavelength control data has wavelength information indicating which wavelength of light is emitted with respect to a wavelength variable light source that emits light of different wavelengths,
    The control means controls the wavelength of the light beam condensed on the optical information recording medium using the wavelength information;
    The optical information processing apparatus according to claim 1, wherein the optical information processing apparatus is an optical information processing apparatus.
  7. 　光情報記録媒体に対して、情報の記録及び再生の少なくとも何れか一方を行う光学的情報処理方法であって、
    　情報の記録又は再生の際、前記光情報記録媒体に記録され得る記録情報毎に、前記光情報記録媒体に集光するビーム光の波長を制御するための情報を示す波長制御データを記憶する所定のメモリから、１又は複数の前記波長制御データを取得する波長制御データ取得工程と、
    　該波長制御データ取得工程で取得された１又は複数の波長制御データに基づいて、前記光情報記録媒体に集光するビーム光の波長を制御する制御工程と、を有する、
    　ことを特徴とする光学的情報処理方法。     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 A wavelength control data acquisition step of acquiring one or a plurality of the wavelength control data from the memory;
    A control step of controlling the wavelength of the light beam condensed on the optical information recording medium based on one or a plurality of wavelength control data acquired in the wavelength control data acquisition step,
    An optical information processing method.
  8. 　前記波長制御データ取得工程では、
    　前記光情報記録媒体に情報を記録する場合には、前記メモリから当該情報に対応する前記波長制御データを取得し、
    　前記光情報記録媒体から情報を再生する場合には、前記メモリから全ての前記波長制御データを取得する、
    　ことを特徴とする請求項７に記載の光学的情報処理方法。     In the wavelength control data acquisition step,
    When recording information on the optical information recording medium, obtain the wavelength control data corresponding to the information from the memory,
    When reproducing information from the optical information recording medium, obtain all the wavelength control data from the memory,
    The optical information processing method according to claim 7.
  9. 　前記光情報記録媒体に記録する情報と前記集光するビーム光の波長との関係が、以下の条件
    　２ｄ≦ｐＣｑ
    　ｄ；光情報記録媒体に記録する情報のビット数
    　ｐ；光情報記録媒体に集光可能なビーム光の波長の設定数
    　ｑ；選択するビーム光の波長の設定数
    を満たしている、
    　ことを特徴とする請求項７又は８に記載の光学的情報処理方法。     Relationship between the wavelength of the light beam to the focusing information to be recorded on the optical information recording medium, the following conditions 2 d ≦ p C q
    d: the number of bits of information to be recorded on the optical information recording medium p: the set number of wavelengths of the beam light that can be collected on the optical information recording medium q: the set number of wavelengths of the light beam to be selected is satisfied,
    The optical information processing method according to claim 7 or 8, wherein
PCT/JP2010/073450 2009-12-28 2010-12-24 Optical information processing device, and optical information processing method WO2011081108A1 (en)

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EP2506256A3 (en) * 2011-03-31 2013-10-16 General Electric Company Multi-wavelength-holographic systems and methods
JP2015176610A (en) * 2014-03-13 2015-10-05 シチズンホールディングス株式会社 Optical recording device

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2506256A3 (en) * 2011-03-31 2013-10-16 General Electric Company Multi-wavelength-holographic systems and methods
JP2015176610A (en) * 2014-03-13 2015-10-05 シチズンホールディングス株式会社 Optical recording device

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