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WO2017060984A1 - Dispositif et procédé de reproduction d'hologramme - Google Patents

Dispositif et procédé de reproduction d'hologramme Download PDF

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Publication number
WO2017060984A1
WO2017060984A1 PCT/JP2015/078436 JP2015078436W WO2017060984A1 WO 2017060984 A1 WO2017060984 A1 WO 2017060984A1 JP 2015078436 W JP2015078436 W JP 2015078436W WO 2017060984 A1 WO2017060984 A1 WO 2017060984A1
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WO
WIPO (PCT)
Prior art keywords
light
reference light
hologram
angle
medium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2015/078436
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English (en)
Japanese (ja)
Inventor
弘充 森
誠 保坂
和良 山崎
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Consumer Electronics Co Ltd
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Hitachi Consumer Electronics Co Ltd
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Publication date
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Priority to PCT/JP2015/078436 priority Critical patent/WO2017060984A1/fr
Publication of WO2017060984A1 publication Critical patent/WO2017060984A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
    • G11B7/0045—Recording
    • 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
    • G11B7/0055—Erasing
    • 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
    • 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
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector

Definitions

  • the present invention relates to an apparatus and method for reproducing information from a recording medium using holography.
  • Patent Document 1 An example of holographic memory technology is, for example, Japanese Patent Application Laid-Open No. 2013-097837 (Patent Document 1).
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2013-097837
  • a hologram reproducing apparatus capable of reducing the time required and a method for searching for an optimum value of the reference light incident angle at the time of reproduction are provided.
  • a solving means “a hologram recording medium 11 on which page data information is angle-multiplexed recorded” is described.
  • a hologram reproducing device that has an information reproducing unit that reproduces page data information by irradiating a reference light during reproduction, and adjusts the information reproducing unit so that a light wave carrying the page data information is obtained.
  • the signal light incident angle ⁇ s, the recording reference light incident angle ⁇ r, the light wavelength ⁇ , the refractive index n of the recording medium, and the recording medium Based the rate ⁇ to the arithmetic expression for an element provided with a computing means 40 for obtaining the desired reproduction reference beam incident angle .phi.read. Has been described as ".
  • Patent Document 2 Another patent document is, for example, Japanese Patent Application Laid-Open No. 2006-268933 (Patent Document 2).
  • Patent Document 2 describes, as a problem, “to provide a holographic device and a method for reproducing a holographic medium that can be reproduced under conditions of a desired angle and wavelength with respect to a wavelength shift due to an angle shift or a change in ambient temperature”.
  • the holography device of the present invention is designed to multiplex-record each predetermined storage area by changing the angle of the reference light applied to the holographic medium.
  • Reference light irradiation means for irradiating, reproduction light emitted from each information data page by the reference light is incident on the detection surface, and data detection means for reproducing information data from the reproduction light, and emitted from the holographic medium by the reference light
  • the reproduced light is used to detect the light intensity of the reproduced light in each of a plurality of predetermined areas on the detection surface and enter the reference light holographic medium.
  • a reference light control means for controlling the incident angle and wavelength of the reference light according to the detection result of the angle and wavelength deviation of the reproduction light.
  • a hologram corresponding to each reference beam angle is called a page
  • a set of pages angle multiplexed in the same area is called a book.
  • a holographic memory device that records and reproduces a disk-shaped medium reproduces a book recorded along the circumferential direction of the medium.
  • the spindle motor feed rotation angle is controlled, and the book positioning operation with respect to the reference light is repeated.
  • the influence of variations in the characteristics of the rotational drive system and the sensor system is inevitable, even if the same feed rotation angle command value is given, the same feed rotation angle cannot be reproduced.
  • Patent Documents 1 and 2 do not disclose from the viewpoint of expanding the allowable value of the relative error, and cannot cope with the problem of improving the reliability and speed of the hologram reproduction.
  • an object of the present invention is to provide a hologram reproducing apparatus and a reproducing method capable of improving the reliability and speed of hologram reproduction.
  • a hologram reproducing apparatus for reproducing a hologram
  • a reference light angle adjusting unit that adjusts a medium incident angle at which the reference light is incident on the recording medium, and the reproducing light from the recording medium is incident and the reproducing light is transmitted
  • An aperture filter having an aperture, a light detection unit that detects light emitted from the aperture filter and outputs a signal based on the detected light, and a hologram to be reproduced based on the signal output from the light detection unit
  • a positional deviation detection unit for detecting a relative positional deviation amount between the recording position of the reproduction target hologram and the irradiation position on the recording medium of the reference light for reproducing the reproduction target hologram
  • the illumination angle adjustment unit adjusts a medium incident angle in a second direction perpendicular to the
  • the figure which shows a hologram reproducing apparatus in an Example The figure explaining an aperture filter and a photodetector in an Example. The figure explaining the light quantity detection on the photodetector light-receiving surface in an Example. The figure explaining the reproduction
  • derivation explanatory drawing of the medium radial direction correction angle of reference light The graph explaining the correction effect in an Example.
  • the graph explaining the correction effect in an Example. 6 is a flowchart for explaining a book reproduction operation in the first embodiment of the present invention.
  • FIG. 6 is a derivation explanatory diagram of a reference light correction angle in a state where there is recording track eccentricity in the embodiment.
  • a flow for explaining the book reproduction operation The figure explaining an optical pick-up in an Example.
  • Embodiment FIG. 1 shows a configuration example of a hologram reproducing apparatus of the present embodiment.
  • the hologram reproducing device 10 is connected to an external control device 91 via an input / output control circuit 90.
  • the image information output from the image sensor 120 of the optical pickup 11 is converted into an electric signal by the signal processing circuit 85, and this electric signal is transmitted to the external control device 91 by the input / output control circuit 90.
  • a mechanism for detecting the deviation amount of the reference beam angle is provided in the optical pickup 11 to provide a servo signal generation circuit.
  • a servo control signal is generated at 83 and the deviation amount is corrected via the servo control circuit 84.
  • Reference numeral 107 denotes a disc-shaped medium
  • 108 denotes a book which is a set of page data already recorded on the medium 107
  • 123 denotes a circumferential direction of the medium 107
  • 124 denotes a radial direction of the medium 107.
  • the book is reproduced along the circumferential direction 123.
  • one book 108 is shown as a book, but actually, a plurality of books 108 are arranged at predetermined intervals along the circumferential direction 123.
  • the medium 107 is mounted on a spindle motor (not shown) and rotates in the circumferential direction 123.
  • the spindle motor is driven in the radial direction 124 by a feed driving mechanism (not shown).
  • This feed drive mechanism is provided with a position sensor 122 and detects the position in the radial direction 124 when the book 108 is played back.
  • the reference light 102 reflects the angle variable mirror 103 held by the actuator 104, passes through the scanner lens 106, and is irradiated onto the book 108 at a predetermined incident angle.
  • an electromagnetic actuator that can tilt the variable angle mirror 103 in the circumferential direction 123 and the radial direction 124 of the medium 107 can be used as the actuator 104, and the incident angle of the reference light 102 with respect to the medium 107 can be changed.
  • the angle sensor 105 that detects the tilt angle of the actuator 104 and the variable angle mirror 103 is connected to the angle control circuit 125, and controls the variable angle mirror 103 to a desired tilt angle by feedback control.
  • the reference light 102 that has passed through the book 108 is reflected by the mirror 109 to become the reproduction reference light 126, enters the medium 107 again, and is diffracted to generate the reproduction light 110.
  • the reproduction light 110 passes through the objective lens 111, the relay lens 112, the aperture filter 113, the PBS 116, and the PBS 119 and is irradiated to the image sensor 120 such as a CCD sensor or a CMOS sensor, thereby reproducing the book.
  • the position of the aperture filter 113 is adjusted to a reference position in the optical system assembly adjustment. Details of the aperture filter 113 will be separately described later with reference to FIGS.
  • the spindle motor feed rotation angle is controlled and the book positioning operation is performed with respect to the reference light.
  • the influence of variations in the characteristics of the drive system and the sensor system is inevitable, so the same feed rotation angle is set every time. I can't control it. Therefore, the positional deviation of the book 108 always occurs with respect to the reference beam 102, and this positional deviation amount changes every time the book positioning operation is performed. Therefore, a means for detecting the amount of displacement is required.
  • the detection speed cannot be increased because the medium 107 is heavy.
  • an image sensor as the positional deviation amount detection means, it takes time and is not suitable for speeding up since it is calculated from image data with a large amount of information.
  • the positional deviation amount is detected at high speed by providing the optical means described below.
  • the contents will be described below.
  • the photodetector 118 is connected to a signal generation circuit 121, which generates a servo signal corresponding to the output signal of the photodetector 118.
  • the aperture actuator 114 is driven so that the servo signal approaches 0, and the aperture filter 113 is positioned. If the driving amount of the aperture filter 113 at this time is detected by a position detection sensor 115 (for example, PSD: Position Sensitive Detector), the relative position error of the reproduction light 110 with respect to the aperture filter 113, that is, the positional deviation amount of the book 108 with respect to the reference light 102 is obtained. Recognize.
  • This optical means drives the light aperture filter 113, and the photodetector that detects only the light quantity has a high response speed, so that it is possible to detect the amount of displacement at high speed.
  • FIG. 2 is a diagram illustrating a configuration example of the aperture filter 113 and the photodetector 118
  • FIG. 3 is a diagram illustrating an example of light amount detection on the light receiving surface of the photodetector 118.
  • FIG. 2A shows an example of the aperture filter 113, and the X direction in the figure corresponds to the circumferential direction 123 of the medium.
  • a transmission region 201 through which the reproduction light 110 passes is provided at the center, four divided wavelength plate regions 202a, 202b, 202c, and 202d are provided around the transmission region 201, and a light blocking region 203 is provided outside the transmission region 201.
  • the light blocking region 203 blocks unnecessary light other than the 0th-order light diffracted from the reproduction target book 108 in the reproduction light 110 or unnecessary light diffracted from an adjacent book other than the reproduction target book 108 and irradiates the image sensor 120. Do not be.
  • FIG. 2B shows an example of the light receiving surface pattern of the photodetector 118.
  • the light receiving surface 206 is divided into light receiving regions A, B, C, and D by dividing lines 204 and 205, and the amount of light received is determined in each region.
  • a corresponding signal is output.
  • FIG. 3 shows the relative positional relationship of the reproduction light 110 with respect to the aperture filter 113 in the upper stage, and the light receiving state on the light receiving surface 206 of the photodetector 118 corresponding to the relative positional relationship shown in the upper stage.
  • the X direction in the figure corresponds to the circumferential direction 123 of the medium as in FIG.
  • FIG. 3A shows a state in which the reproduction light 110 passes through the transmission region 201 of the aperture filter 113.
  • the relative position error of the reproduction light 110 with respect to the aperture filter 113 is within a predetermined range, and the position detection light of the book 108 is not irradiated to the photodetector 118, from any of the light receiving areas A, B, C, and D However, no signal is output.
  • (B) shows a state where the relative position of the reproduction light 110 with respect to the aperture filter 113 is shifted in the + X direction. The relative position error in the + X direction exceeds the predetermined range, and the position detection signal light 1103 of the book 108 is applied to the light receiving region A of the photodetector 118.
  • (C) shows a state where the relative position of the reproduction light 110 with respect to the aperture filter 113 is shifted in the ⁇ X direction.
  • the relative position error in the ⁇ X direction exceeds a predetermined range, and the position detection signal light 1105 of the book 108 is applied to the light receiving region B of the photodetector 118.
  • the position error signal SX in the X direction is obtained by (Equation 1), and the relationship between the relative position error in the X direction and the position error signal SX. Is a linear relationship.
  • the aperture actuator 114 is driven so that SX approaches 0, and the aperture filter 113 is positioned.
  • a position detection sensor for example, PSD
  • the relative position error of the reproduction light 110 with respect to the aperture filter 113 that is, the positional deviation amount of the book 108 with respect to the reference light 102 is known.
  • the relationship between the detection drive amount E of the aperture filter 113 and the positional deviation amount D of the book 108 is expressed by the following (formula 2) depending on the magnification (ratio of the focal length f1 of the relay lens 112 and the focal length f2 of the objective lens 111). Therefore, the positional deviation amount D of the book 108 can be obtained from the detection drive amount E of the aperture filter 113.
  • (Formula 2) E D ⁇ (f1 / f2)
  • four wavelength plate regions are provided around the transmission region 201 of the aperture filter 113 and four light receiving regions are provided on the light receiving surface 206 of the photodetector 118.
  • the present invention is not limited to this.
  • the aperture filter 113 shown in the figure has the wave plate regions 202a and 202b, and the light receiving surface 206 has the light receiving regions A and B.
  • the positional deviation amount D of the book 108 can be detected by the optical means described above, and the subsequent operation will be described below.
  • the book position deviation detection unit 127 is connected to the position detection sensor 115 and the signal generation circuit 121, stores the position deviation detection result of the book 108 with respect to the reference light 102, and transmits the result to the reference light correction angle calculation unit 129. Further, the position information of the medium 107 in the radial direction 124 is transmitted from the reproduction radius position detection unit 135 to the reference light correction angle calculation unit 129. Further, irradiation angle information of the reference light 102 in the medium circumferential direction 123 is transmitted from the angle control circuit 125 of the angle variable mirror 103 to the reference light correction angle calculation unit 129.
  • the reference light correction angle calculation unit 129 calculates the correction angle of the reference light in the medium radial direction 124 from the transmitted information, stores the result, and transmits the result to the reference light angle change command unit 130.
  • the reference light angle change command unit 130 transmits the command value of the correction angle to the angle control circuit 125 of the angle variable mirror 103 and controls the angle control circuit 125.
  • the angle control circuit 125 performs feedback control by driving the actuator 104 and the output from the angle sensor 105, and changes the angle of the angle variable mirror 103 so as to change the incident angle of the reference light in the medium radial direction 124.
  • the irradiation angle of the reference beam 102 to the reproduction target book 108 in the medium radial direction 124 is changed.
  • the correction angle of the reference beam 102 in the medium radial direction 124 is calculated again as described above, and the book to be reproduced is reproduced. It is comprised so that the reference light irradiation angle with respect to may be changed.
  • the medium 107 may be tilted without changing the reference light irradiation angle.
  • the medium 107 is heavy, the angle cannot be changed at high speed.
  • the lightweight variable angle mirror 103 is driven, the angle can be changed at high speed.
  • FIG. 4A shows a relative shift state between the reference beam 102 and the reproduction target book 108 that occurs when the medium 107 is rotated in the direction 402 around the rotation center 401 and the book 108 is reproduced.
  • (State 1) is an ideal state with no relative deviation, and can be reproduced without any particular problem.
  • (State 2) shows a state in which a relative shift occurs.
  • a translational shift + D and a clockwise rotation angle + ⁇ occur simultaneously with respect to the reference beam 102.
  • a translational shift ⁇ D and a counterclockwise rotation angle ⁇ occur simultaneously with respect to the reference beam 102.
  • FIG. 5 shows the book 108 to be reproduced assuming (state 2) in FIG. 4.
  • the reference light 102 is incident at a predetermined angle ⁇ b in the circumferential direction 123 of the medium, and page reproduction is performed. Assumes to do.
  • the reproduction target book 108 is inclined by ⁇ with respect to the reference light 102, so that when viewed from the book 108, the reproduction target book 108 is in a direction of a line 502 connecting the rotation center 401 of the medium and the center 501 of the book 108.
  • the reference light 102 is tilted by ⁇ 1 and irradiated with the reference light.
  • FIG. 4B described above is a diagram specifically showing the circumferential position displacement amount D of the reproduction target book 108, and the following relational expression is geometrically established.
  • D R ⁇ Sin ⁇
  • the first feature is an angle correction operation for changing the reference light correction angle ⁇ 2 in accordance with the medium radial position R of the reference light.
  • FIG. 6 is a diagram showing the relationship between the deviation amount of the reproduction target book and the correction angle.
  • the horizontal axis indicates the medium circumferential direction deviation D of the book to be reproduced
  • the left vertical axis indicates ⁇ p
  • the right vertical axis indicates ⁇ 2
  • the reference light medium incident angle ⁇ b in the medium circumferential direction is shown. 48 degrees was set.
  • FIG. 6A shows a case where the reference light position R measured from the rotation center of the medium is set to the innermost radius of the medium 24 mm in FIG. 6A and to the outermost radius of the medium 64 mm in FIG.
  • a dotted characteristic line 601 indicates ⁇ 1 in (Expression 3). For example, when D is ⁇ 100 ⁇ m, it reaches ⁇ 0.2 degrees and cannot be reproduced.
  • the characteristic line 602 of the one-dot chain line indicates ⁇ 2 in (Expression 4), and the angle deviation ⁇ p can be set to 0 (straight line 603), so that stable reproduction is possible.
  • a dotted characteristic line 604 indicates ⁇ 1 in (Equation 3). For example, when D is ⁇ 100 ⁇ m, it reaches ⁇ 0.1 ° and cannot be reproduced.
  • a dashed-dotted characteristic line 605 indicates ⁇ 2 in (Equation 4), and the angle deviation ⁇ p can be set to 0 (straight line 606), thereby enabling stable reproduction.
  • ⁇ 1 varies depending on the medium radial position R of the reference light.
  • the innermost radius 24 mm is approximately twice as large as the outermost radius 64 mm. Therefore, in this embodiment, an angle correction operation for changing the reference light correction angle ⁇ 2 according to the medium radius position R of the reference light 102 is performed.
  • the angle deviation ⁇ p can be set to 0 regardless of the medium radial position R, and stable reproduction is possible.
  • the second feature is an angle correction operation in which the reference light correction angle ⁇ 2 is changed according to the incident angle ⁇ b of the reference light in the circumferential direction of the medium.
  • FIG. 7 is a diagram showing the relationship between the incident angle of the reference light and the correction angle.
  • a plurality of pages are recorded in the book 108 by angle multiplex recording in which the medium circumferential incident angle ⁇ b of the reference light is set within a predetermined range, for example, 33 degrees to 63 degrees, and is changed at predetermined angular intervals.
  • the angle of incidence ⁇ b of the reference beam 102 is changed at a predetermined angular interval from 33 degrees to 63 degrees by changing the variable angle mirror 103 in the circumferential direction 123 of the medium at a predetermined angular interval.
  • FIG. 7 shows an example in which R is set to 24 mm, D is set to 100 ⁇ m, the horizontal axis incident angle ⁇ b of the reference light in the horizontal axis, the left vertical axis to the angular deviation ⁇ p, and the right vertical axis to the correction angle ⁇ 2. It is the graph shown.
  • a dotted characteristic line 701 indicates ⁇ 1 in (Equation 3).
  • the characteristic line 702 of the alternate long and short dash line indicates ⁇ 2 in (Equation 4), and the angle deviation ⁇ p can be set to 0 (straight line 703), thereby enabling stable page data reproduction.
  • ⁇ 1 varies depending on the incident angle ⁇ b of the reference light.
  • the characteristic line 701 when ⁇ b is 63 degrees, the value is about twice as large as when ⁇ b is 33 degrees. Therefore, it is necessary to change ⁇ 2 correspondingly. Therefore, in the present embodiment, when each page data is reproduced, an angle correction operation for changing the correction angle ⁇ 2 according to the incident angle ⁇ b of the reference light 102 is performed.
  • This angle correction operation makes it possible to set the angle deviation ⁇ p to 0 regardless of ⁇ b, and stable page data reproduction is possible.
  • the allowable range of D can be expanded from the conventional ⁇ 10 ⁇ m, there is an effect of improving the reproduction reliability of the apparatus.
  • FIG. 8 shows a playback operation flow.
  • the trigger for the reference beam angle correction operation is the timing of moving the book to be played.
  • the feed rotation angle of the spindle motor is controlled, and the book positioning operation is performed with respect to the reference light.
  • the positional deviation amount D of the book 108 with respect to the reference beam 102 does not become the same as the previous book reproduction and changes. That is, the correction angle ⁇ 2 of the reference beam 102 has changed from the previous book reproduction. Therefore, it is necessary to change ⁇ 2 corresponding to the book movement.
  • an angle correction operation for changing the correction angle ⁇ 2 in accordance with the movement of the book to be reproduced is performed. Further, when each page is reproduced, as described in the second feature, an angle correction operation for changing the reference light correction angle ⁇ 2 according to the incident angle ⁇ b of the reference light 102 is performed.
  • FIG. 8 shows a playback operation flow.
  • step S ⁇ b> 801 the book is moved by controlling the feed rotation angle of the spindle motor, and the target book on the medium 107 is positioned with respect to the reference beam 102.
  • the medium radial position of the reference beam 102 is detected.
  • step S802 the irradiation angle in the medium circumferential direction 123 of the reference beam 102 with respect to the target book 108 in the medium 107 is set to an angle necessary for desired page reproduction.
  • step S803 the irradiation angle of the reference light 102 in the medium circumferential direction 123 is detected, and the target book 108 is irradiated with the reference light 102.
  • step S804 the amount and direction of the positional deviation between the target book and the reference light in the circumferential direction of the medium 107 are detected.
  • step S805 based on the information acquired up to step S804 (the medium radial position of the reference light 102, the irradiation angle in the medium circumferential direction 123, and the amount of positional deviation from the target book in the circumferential direction of the medium 107), the reference light 102
  • the correction angle of the irradiation angle in the medium radial direction 124 is calculated, and the irradiation angle of the reference light 102 in the medium radial direction 124 is corrected and changed.
  • page reproduction is executed in step S806.
  • step S806 If the page reproduction is executed in S806, it is determined whether or not another page is reproduced in S807. When reproducing another page, the process returns to step S802, and the operations from step S802 to step S805 are performed again. Each time the playback page changes, the irradiation angle of the reference beam 102 in the medium circumferential direction 123 changes. Accordingly, the correction angle of the irradiation angle of the reference beam 102 in the medium radial direction 124 is changed to the previous page playback. Change to a value different from the time. Thereafter, another page reproduction is executed in step S806.
  • step S808 When the page reproduction is completed, it is determined whether or not another book is reproduced in S808. When reproducing another book, the process returns to step S 801, the book is moved, and the target book 108 on the medium 107 is positioned with respect to the reference beam 102. The operations from step S802 to step S806 are performed again.
  • the correction angle of the irradiation angle of the reference light 102 in the medium radial direction 124 is set accordingly. Change to a value different from the previous book playback.
  • the Example of a present Example is as follows when the effect acquired is put together.
  • (1) Regarding the disturbance during book reproduction, that is, the relative deviation between the book to be reproduced and the reference beam in the circumferential direction of the medium, the allowable value can be increased, so that the reliability of hologram reproduction can be improved.
  • (2) As a means for detecting deviation information between the book to be reproduced and the reference light, an aperture filter which is a light optical element rather than a heavy medium is driven, and a light detector dedicated to light amount detection is used instead of an image pickup element for detecting image information. As a result, deviation information can be detected at high speed.
  • the reflection mirror which is a light optical element rather than a heavy medium, is feedback-controlled based on deviation information from the deviation information detection means, so that the angle Changes can be made at high speed. Therefore, the reproduction speed can be increased.
  • a present Example is not limited to the said Example, Various modifications are included.
  • the detection optical system including the aperture filter 113, the PBS 116, the detection lens 117, and the photodetector 118 is provided as an optical detection unit for the book 108 positional deviation.
  • a detection optical system including a detection lens for example, a photodetector having a two-divided light receiving surface may be used so as to face the objective lens 111 with the medium 107 interposed therebetween.
  • the photodetector may be an image sensor such as a CCD or CMOS.
  • one angle variable mirror is inclined in two axial directions, ie, the circumferential direction and the radial direction of the medium.
  • the first variable angle mirror is arranged in the circumferential direction of the medium.
  • the variable angle mirror may be inclined in the radial direction of the medium.
  • FIG. 9 shows the eccentricity of the track generated at the time of recording.
  • 901 indicates a medium
  • 903 indicates an ideal track at a predetermined radius R
  • 902 indicates the center of the ideal track 903.
  • Reference numeral 905 denotes a recording track
  • the center 904 of the track 905 is decentered from the center 902 by ⁇ .
  • FIG. 10 shows a hologram reproducing apparatus according to the present embodiment, where 1006 is a hologram reproducing apparatus, 1001 is an optical pickup, and 1005 is an optical system of the optical pickup 1001.
  • 1006 is a hologram reproducing apparatus
  • 1001 is an optical pickup
  • 1005 is an optical system of the optical pickup 1001.
  • the same part as FIG. 1 of Example 1 is shown using the same code
  • the hologram reproducing device 1006 is connected to the external control device 91 via the input / output control circuit 90.
  • the image information output from the image sensor 120 of the optical pickup 1001 is converted into an electric signal by the signal processing circuit 85, and this electric signal is transmitted to the external control device 91 by the input / output control circuit 90.
  • the optical pickup 1001 of this embodiment is different from the optical pickup 11 shown in FIG. 1 in that an eccentricity detecting optical means for detecting the eccentricity ⁇ of the track 905 is added.
  • the decentering detection optical means includes a detection lens 1002 and a light detector 1003 provided so as to face the objective lens 111 with the medium 107 interposed therebetween.
  • the reference light 102 irradiated to the book 108 is divided into transmitted light directed to the mirror 109 and diffracted light 1004 directed to the detection lens 1002, and among these, the diffracted light 1004 is used as the eccentricity detection light.
  • the diffracted light 1004 is collected by the detection lens 1002 and irradiated to the photodetector 1003.
  • FIG. 11 shows the light receiving surface of the photodetector 1003.
  • the light receiving surface 1101 of the photodetector 1003 is divided into four light receiving areas 1105a, 1105b, 1105c, and 1105d by a dividing line 1103 and a dividing line 1104, and a light spot 1102 is irradiated to these light receiving areas.
  • the X direction in the figure corresponds to the circumferential direction 123 of the medium 107, and the Y direction corresponds to the radial direction 124 of the medium 107.
  • the eccentricity detection unit 1006 stores the detection result of the eccentricity amount ⁇ and transmits it to the reference light correction angle calculation unit 129. Note that the relationship between the amount of eccentricity ⁇ and the amount of movement of the light spot 1102 is calibrated during assembly adjustment of the optical pickup. Since other parts are the same as those in the first embodiment, description thereof is omitted here.
  • the reference beam correction angle necessary for the radial direction 124 of the medium is derived when the book is reproduced with the recording track being decentered with reference to FIG.
  • FIG. 12A shows a state where the recording track 905 is decentered by ⁇ from the ideal track 903, as shown in FIG.
  • the book 108 is inclined at an angle ⁇ when viewed from the center 1204 of the recording track 905, and the angle ⁇ is expressed by the following (formula 8).
  • (Formula 8) ⁇ ⁇ / R
  • FIG. 12B shows a state in which the book 108 is on the ideal track 903 and the shift amount D is generated in the book positioning operation as shown in the first embodiment.
  • the book 108 is inclined by an angle ⁇ as viewed from the center 902 of the ideal track 903, and this angle ⁇ is expressed in the same manner as in (Equation 6) or (Equation 6 ′) of the first embodiment.
  • FIG. 8 shows a state where the recording track 905 is decentered by ⁇ from the ideal track 903, as shown in FIG.
  • the book 108 is inclined at an angle ⁇ when viewed from the center 1204 of the recording track 905, and the angle
  • the reference light correction angle ⁇ 2 necessary for the radial direction 124 of the medium can be calculated by the following formula in which ⁇ in (Formula 4) of the first embodiment is replaced by ( ⁇ + ⁇ ).
  • step S1301 the target track is moved, and in step S1302, the spindle motor is rotated to detect the eccentricity of the recording track.
  • step S ⁇ b> 801 the feed rotation angle of the spindle motor is controlled to move the book, and the target book on the medium 107 is positioned with respect to the reference beam 102. At this time, the medium radial position of the reference beam 102 is detected.
  • step S802 the irradiation angle in the medium circumferential direction 123 of the reference beam 102 with respect to the target book 108 in the medium 107 is set to an angle necessary for desired page reproduction.
  • step S803 the irradiation angle of the reference light 102 in the medium circumferential direction 123 is detected, and the target book 108 is irradiated with the reference light 102.
  • step S804 the amount and direction of the positional deviation between the target book and the reference light in the circumferential direction of the medium 107 are detected.
  • step S1303 Information acquired up to step S1204 in step S1303 (the medium radial position of the reference beam 102, the amount of eccentricity of the recording track, the irradiation angle in the medium circumferential direction 123, and the amount of positional deviation from the target book in the circumferential direction of the medium 107)
  • the correction angle of the irradiation angle of the reference light 102 in the medium radial direction 124 is calculated, and the irradiation angle of the reference light 102 in the medium radial direction 124 is corrected and changed. Thereafter, page reproduction is executed in step S806.
  • step S2104 determines whether another track is to be reproduced.
  • the process returns to step S2101 to move to the target track. The operations from step S2101 to step S2104 are performed again.
  • the present embodiment is characterized by an angle correction operation in which the reference light correction angle ⁇ 2 is changed in accordance with the amount of eccentricity of the recording track of the medium. Since the influence of the track eccentricity generated during recording can be compensated, the recording of the reproducing method apparatus Speed can be improved.
  • FIG. 14 shows the configuration of the optical pickup in this embodiment.
  • the optical pickup 1401 includes a wedge prism 1403.
  • Reference numeral 1401 denotes an optical pickup in the present embodiment, and the optical pickup 1401 is connected to the signal generation circuit 86, servo control circuit 84, servo signal generation circuit 83, and signal processing circuit 85 shown in FIG.
  • a hologram reproducing apparatus is configured.
  • the same part as Example 1 is shown using the same code
  • the reference light 102 passes through the wedge prism 1403 having a predetermined apex angle, is reflected by the mirror 1407, passes through the scanner lens 106, and is irradiated onto the medium 107 at a predetermined incident angle.
  • the wedge prism 1603 is held by an actuator 1604 that is rotationally driven in one axis direction, and the incident angle of the medium 107 in the radial direction 124 can be changed by rotationally driving the wedge prism 1403.
  • An actuator 1404 and an angle sensor 1405 for detecting the rotation angle of the wedge prism 1403 are connected to the pitch angle control circuit 1619 and control the wedge prism 1403 to a desired rotation angle by feedback control.
  • the mirror 1407 is held by an actuator 1406 that is rotationally driven in one axis direction, and the incident angle in the circumferential direction 123 of the medium 107 can be changed by rotationally driving the mirror 1407.
  • An actuator 1406 and an angle sensor 1409 for detecting the rotation angle of the mirror 1407 are connected to a Bragg angle control circuit 1418 and control the mirror 1407 to a desired rotation angle by feedback control.
  • the reference light 102 irradiated on the book 108 is divided into transmitted light directed to the mirror 109 and diffracted light 1410 directed to the detection lens 1611.
  • This diffracted light 1410 is separated into two polarized light beams having different polarization directions by the polarization separation element 1602.
  • the light in one polarization direction passes through the PBS 1413 and is collected on the photodetector 1415 by the detection lens 1414.
  • the light in the other polarization direction is reflected by the PBS 1413 and collected by the detection lens 1416 on the photodetector 1417. Signals obtained by the photodetectors 1415 and 1417 are used by the Bragg angle control circuit 1418 to generate the control angle signal of ⁇ b.
  • the irradiation angle information regarding the medium circumferential direction 123 of the reference light 102 is transmitted from the Bragg angle control circuit 1418 to the reference light correction angle calculation unit 129.
  • the reference light correction angle calculation unit 129 calculates a correction angle of the reference light in the medium radial direction 124 from the transmitted information, stores the result, and transmits the result to the reference light angle change command unit 130.
  • the reference light angle change command unit 130 transmits the command value of the correction angle to the pitch angle control circuit 1419 and controls the pitch angle control circuit 1419.
  • the pitch angle control circuit 1619 performs feedback control by driving the actuator 1404 and the output from the angle sensor 1605 to change the angle of the wedge prism 1403 in the medium radial direction 124. In this way, the irradiation angle of the reference beam 102 to the reproduction target book 108 in the medium radial direction 124 is changed.
  • the incident angle of the reference beam 102 in the circumferential direction 123 can be controlled at high speed during page reproduction. Since the scanning speed of the incident angle ⁇ b in the medium circumferential direction of the reference light is increased, it is possible to provide a hologram reproducing apparatus having an improved reproducing speed as compared with the hologram reproducing apparatus of the first embodiment.
  • a correction optical unit that optically detects the shift state of the reproduction target area of the hologram medium, and correction that changes the irradiation angle of the reference light based on the shift information of the reproduction target area acquired from the detection optical unit.
  • the hologram reproduction apparatus As a second modification, the hologram reproduction apparatus according to the first modification, wherein the correction is performed when the reproduction target area is moved.
  • the hologram reproduction apparatus As a third modification, the hologram reproduction apparatus according to the first modification, wherein the correction is performed when the reproduction target page is changed.
  • the detection optical unit is provided in an optical path between the medium and the image sensor, and the aperture filter optical element that causes the image sensor to receive only the 0th-order light of the diffracted light; and A detection lens, a photodetector, and an actuator for driving the aperture filter optical element are provided to detect a shift state of a reproduction target area of the hologram medium as a change in state of zero-order light passing through the aperture filter optical element.
  • Hologram playback device is provided in an optical path between the medium and the image sensor, and the aperture filter optical element that causes the image sensor to receive only the 0th-order light of the diffracted light; and A detection lens, a photodetector, and an actuator for driving the aperture filter optical element are provided to detect a shift state of a reproduction target area of the hologram medium as a change in state of zero-order light passing through the aperture filter optical element.
  • a reproducing method of a hologram apparatus for reproducing the page data by irradiating a hologram medium on which page data is angle-multiplexed recorded with reference light and receiving the generated diffracted light as reproducing light by an imaging device.
  • control lines indicate what is considered necessary for the explanation, and not all control lines are necessarily shown on the product.

Landscapes

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

Abstract

L'invention concerne un dispositif et un système de reproduction d'hologramme permettant d'améliorer la fiabilité et d'améliorer ainsi la vitesse de reproduction d'un hologramme. L'invention concerne un dispositif de reproduction d'hologramme qui modifie, au moyen d'une lumière de référence, un support d'enregistrement dans lequel l'angle d'incidence de la lumière de référence est modifié dans une première direction et un hologramme a été enregistré par multiplexage angulaire, et reproduit l'hologramme enregistré en recevant, au moyen d'un élément d'imagerie, une lumière diffractée générée en tant que lumière de reproduction, le dispositif de reproduction d'hologramme étant caractérisé en ce qu'il comprend : une unité de réglage d'angle de lumière de référence qui règle un angle d'incidence de support auquel la lumière de référence pénètre dans le support d'enregistrement ; un filtre d' ouverture comprenant une ouverture par laquelle pénètre la lumière de reproduction du support d'enregistrement et par laquelle la lumière de reproduction est transmise ; une unité de détection de lumière qui détecte la lumière émise par le filtre d'ouverture et génère un signal d'après la lumière détectée ; et une unité de détection d'écart de position qui, d'après le signal généré par l'unité de détection de lumière, détecte un degré d'écart de position relatif entre la position d'enregistrement d'un hologramme devant être reproduit et la position d'irradiation sur le support d'enregistrement de la lumière de référence afin de reproduire l'hologramme qui doit être reproduit. L'unité de réglage d'angle de lumière de référence règle un angle d'incidence de support de la lumière de référence dans une seconde direction qui est perpendiculaire à la première direction d'après le degré d'écart de position détecté par l'unité de détection d'écart de position.
PCT/JP2015/078436 2015-10-07 2015-10-07 Dispositif et procédé de reproduction d'hologramme Ceased WO2017060984A1 (fr)

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006208921A (ja) * 2005-01-31 2006-08-10 Alps Electric Co Ltd ホログラフィー記録装置，再生装置及びその方法並びにホログラフィー媒体
JP2006251355A (ja) * 2005-03-10 2006-09-21 Sharp Corp 情報再生装置および情報再生方法
JP2014089779A (ja) * 2012-10-29 2014-05-15 Nippon Hoso Kyokai <Nhk> ２次元符号復号装置およびそのプログラム、ならびに、ホログラム記録再生装置
WO2014188540A1 (fr) * 2013-05-22 2014-11-27 株式会社日立製作所 Dispositif de positionnement de composant optique et dispositif d'enregistrement optique l'utilisant
WO2015040681A1 (fr) * 2013-09-18 2015-03-26 日立コンシューマエレクトロニクス株式会社 Appareil de reproduction d'hologramme et procédé de reproduction d'hologramme
JP2015082327A (ja) * 2013-10-21 2015-04-27 株式会社日立エルジーデータストレージ 光情報再生装置、光情報再生方法および光情報記録方法
WO2015114743A1 (fr) * 2014-01-29 2015-08-06 日立コンシューマエレクトロニクス株式会社 Dispositif d'informations optiques et procédé de traitement d'informations optiques

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006208921A (ja) * 2005-01-31 2006-08-10 Alps Electric Co Ltd ホログラフィー記録装置，再生装置及びその方法並びにホログラフィー媒体
JP2006251355A (ja) * 2005-03-10 2006-09-21 Sharp Corp 情報再生装置および情報再生方法
JP2014089779A (ja) * 2012-10-29 2014-05-15 Nippon Hoso Kyokai <Nhk> ２次元符号復号装置およびそのプログラム、ならびに、ホログラム記録再生装置
WO2014188540A1 (fr) * 2013-05-22 2014-11-27 株式会社日立製作所 Dispositif de positionnement de composant optique et dispositif d'enregistrement optique l'utilisant
WO2015040681A1 (fr) * 2013-09-18 2015-03-26 日立コンシューマエレクトロニクス株式会社 Appareil de reproduction d'hologramme et procédé de reproduction d'hologramme
JP2015082327A (ja) * 2013-10-21 2015-04-27 株式会社日立エルジーデータストレージ 光情報再生装置、光情報再生方法および光情報記録方法
WO2015114743A1 (fr) * 2014-01-29 2015-08-06 日立コンシューマエレクトロニクス株式会社 Dispositif d'informations optiques et procédé de traitement d'informations optiques

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