WO2013038745A1 - Holographic memory playback device, holographic memory playback method, and hologram recording medium - Google Patents

Holographic memory playback device, holographic memory playback method, and hologram recording medium Download PDF

Info

Publication number
WO2013038745A1
WO2013038745A1 PCT/JP2012/061039 JP2012061039W WO2013038745A1 WO 2013038745 A1 WO2013038745 A1 WO 2013038745A1 JP 2012061039 W JP2012061039 W JP 2012061039W WO 2013038745 A1 WO2013038745 A1 WO 2013038745A1
Authority
WO
WIPO (PCT)
Prior art keywords
recording medium
hologram recording
light
reference light
information
Prior art date
Application number
PCT/JP2012/061039
Other languages
French (fr)
Japanese (ja)
Inventor
利樹 石井
Original Assignee
日立コンシューマエレクトロニクス株式会社
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 日立コンシューマエレクトロニクス株式会社 filed Critical 日立コンシューマエレクトロニクス株式会社
Publication of WO2013038745A1 publication Critical patent/WO2013038745A1/en

Links

Images

Classifications

    • 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
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/095—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following specially adapted for discs, e.g. for compensation of eccentricity or wobble
    • G11B7/0956—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following specially adapted for discs, e.g. for compensation of eccentricity or wobble to compensate for tilt, skew, warp or inclination of the disc, i.e. maintain the optical axis at right angles to the disc
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
    • G03H1/2202—Reconstruction geometries or arrangements
    • G03H2001/2223—Particular relationship between light source, hologram and observer

Definitions

  • the present invention relates to an apparatus and method for reproducing information from a recording medium using holography, and a hologram recording medium.
  • the Blu-ray Disc (TM) standard using a blue-violet semiconductor laser has made it possible to commercialize an optical disc having a recording density of about 50 GB even for consumer use.
  • HDD Hard Disc Drive
  • Hologram recording technology is a method in which signal light having page data information two-dimensionally modulated by a spatial light modulator is superimposed on reference light inside the recording medium, and the interference fringe pattern generated at that time is placed in the recording medium. This is a technique for recording information on a recording medium by causing refractive index modulation.
  • the hologram recorded in the recording medium acts like a diffraction grating to generate diffracted light. This diffracted light is reproduced as the same light including the recorded signal light and phase information.
  • Regenerated signal light is detected two-dimensionally at high speed using a photodetector such as a CMOS or CCD.
  • a photodetector such as a CMOS or CCD.
  • the hologram recording technique enables two-dimensional information to be recorded on the optical recording medium at once by one hologram and further reproduces this information. Since the page data can be overwritten, large-capacity and high-speed information recording / reproduction can be achieved.
  • Patent Document 1 states that “a reference tilt hologram for defining a reference incident angle in the radial tilt direction is recorded in a holographic memory medium. Reference light is irradiated to the hologram recording position, and the reference incident angle (reference angle Sr) of the reference light in the radial tilt direction is detected from the light receiving state, and a tilt actuator that displaces the holographic memory medium in the radial tilt direction The incident angle of the reference light in the radial tilt direction is matched with the reference angle Sr by driving and controlling 19. Then, the holographic memory medium is irradiated with the signal light and the reference light to execute the recording / reproducing operation. (Summary).
  • the object of the present invention is to provide a means for detecting the tilt of a recording medium without using a reference hologram or an additional apparatus configuration, so that the recording medium once removed from the apparatus has a good quality when it is reattached. It is to be reproducible.
  • Diagram showing the principle for detecting the tilt of a hologram recording medium Diagram showing the principle for detecting the tilt of a hologram recording medium
  • Diagram showing the principle for detecting the tilt of a hologram recording medium Schematic diagram showing an embodiment of an optical information recording / reproducing apparatus Schematic showing an embodiment of a pickup in an optical information recording / reproducing apparatus Schematic showing an embodiment of a pickup in an optical information recording / reproducing apparatus Schematic showing an embodiment of the operation flow of the optical information recording / reproducing apparatus Schematic showing an embodiment of the operation flow of the optical information recording / reproducing apparatus Schematic showing an embodiment of the operation flow of the optical information recording / reproducing apparatus
  • the figure which showed the position where the reference light used in order to detect the inclination of a hologram recording medium reflects in a hologram recording medium
  • movement flow for performing the inclination detection of the hologram recording medium in 1st Example The figure which showed an example of the operation
  • FIG. 2 is a block diagram showing a recording / reproducing apparatus for a hologram recording medium for recording and / or reproducing digital information using holography.
  • the optical information recording / reproducing apparatus 10 includes a pickup 11, a reproducing reference light optical system 12, a cure optical system 13, a disk rotation angle detecting optical system 14, a rotation motor 50, and a disk tilt mechanism 90, and a hologram recording medium. 1 is configured to be rotated by the rotary motor 50 and to correct the tilt by the disc tilt mechanism 90.
  • the pickup 11 plays a role of emitting reference light and signal light to the hologram recording medium 1 and recording digital information on the recording medium using holography.
  • the information signal to be recorded is sent by the controller 89 to the spatial light modulator in the pickup 11 via the signal generation circuit 86, and the signal light is modulated by the spatial light modulator.
  • the reproduction reference light optical system 12 When the information recorded on the hologram recording medium 1 is reproduced, the reproduction reference light optical system 12 generates a light wave that causes the reference light emitted from the pickup 11 to enter the hologram recording medium in a direction opposite to that at the time of recording. .
  • Reproduction light reproduced by the reproduction reference light is detected by a photodetector (to be described later) in the pickup 11, and a signal is reproduced by the signal processing circuit 85.
  • the irradiation time of the reference light and the signal light applied to the hologram recording medium 1 can be adjusted by controlling the opening / closing time of the shutter in the pickup 11 by the controller 89 via the shutter control circuit 87.
  • the cure optical system 13 plays a role of generating a light beam used for pre-cure and post-cure of the hologram recording medium 1.
  • Pre-curing is a pre-process for irradiating a predetermined light beam in advance before irradiating the reference light and signal light to the desired position when recording information at the desired position in the hologram recording medium 1.
  • Post-cure is a post-process for irradiating a predetermined light beam after recording information at a desired position in the hologram recording medium 1 so that additional recording cannot be performed at the desired position.
  • the disk rotation angle detection optical system 14 is used to detect the rotation angle of the hologram recording medium 1.
  • a signal corresponding to the rotation angle is detected by the disk rotation angle detection optical system 14, and the disk rotation motor control circuit 88 is detected by the controller 89 using the detected signal.
  • the rotation angle of the hologram recording medium 1 can be controlled via
  • the angle of the recording medium which will be described later, is detected, and the disc tilt mechanism 90 is driven by the controller 89 via the disc tilt control circuit 91 using the detected signal.
  • the inclination of the hologram recording medium 1 can be controlled.
  • a predetermined light source driving current is supplied from the light source driving circuit 82 to the light sources in the pickup 11, the cure optical system 13, and the disk rotation angle detection optical system 14, and each light source emits a light beam with a predetermined light amount. Can do.
  • the pickup 11 and the disc cure optical system 13 are provided with a mechanism capable of sliding the position in the radial direction of the hologram recording medium 1, and the position is controlled via the access control circuit 81.
  • the recording technique using the principle of angle multiplexing of holography tends to have a very small tolerance for the deviation of the reference beam angle.
  • a mechanism for detecting the deviation amount of the reference beam angle is provided in the pickup 11, a servo control signal is generated by the servo signal generation circuit 83, and the deviation amount is corrected via the servo control circuit 84. It is necessary to provide a servo mechanism for this purpose in the optical information recording / reproducing apparatus 10.
  • the pickup 11, the cure optical system 13, and the disk rotation angle detection optical system 14 may be simplified by combining several optical system configurations or all optical system configurations into one.
  • FIG. 3 shows a recording principle in an example of a basic optical system configuration of the pickup 11 in the optical information recording / reproducing apparatus 10.
  • the light beam emitted from the light source 201 passes through the collimator lens 202 and enters the shutter 203.
  • the optical element 204 composed of, for example, a half-wave plate or the like, adjusts the light quantity ratio of p-polarized light and s-polarized light to a desired ratio.
  • the light beam enters a PBS (Polarization Beam Splitter) prism 205.
  • PBS Polarization Beam Splitter
  • the light beam that has passed through the PBS prism 205 functions as signal light 206, and after the light beam diameter is expanded by the beam expander 208, the light beam passes through the phase mask 209, the relay lens 210, and the PBS prism 211 and passes through the spatial light modulator 212. Is incident on.
  • the signal light to which information is added by the spatial light modulator 212 reflects the PBS prism 211 and propagates through the relay lens 213 and the spatial filter 214. Thereafter, the signal light is condensed on the hologram recording medium 1 by the objective lens 215.
  • the light beam reflected by the PBS prism 205 works as reference light 207, and is set to a predetermined polarization direction according to recording or reproduction by the polarization direction conversion element 216, and then galvanically passed through the mirror 217 and the mirror 218. Incident on the mirror 219. Since the angle of the galvanometer mirror 219 can be adjusted by the actuator 220, the incident angle of the reference light incident on the hologram recording medium 1 after passing through the lens 221 and the lens 222 can be set to a desired angle. In order to set the incident angle of the reference light, an element that converts the wavefront of the reference light may be used instead of the galvanometer mirror.
  • the signal light and the reference light are incident on the hologram recording medium 1 so as to overlap each other, whereby an interference fringe pattern is formed in the recording medium, and information is recorded by writing this pattern on the recording medium.
  • the incident angle of the reference light incident on the hologram recording medium 1 can be changed by the galvanometer mirror 219, recording by angle multiplexing is possible.
  • holograms corresponding to each reference beam angle are called pages, and a set of pages angle-multiplexed in the same area is called a book. .
  • FIG. 4 shows a reproduction principle in an example of a basic optical system configuration of the pickup 11 in the optical information recording / reproducing apparatus 10.
  • the reference beam is incident on the hologram recording medium 1 as described above, and the light beam transmitted through the hologram recording medium 1 is reflected by the galvanometer mirror 224 whose angle can be adjusted by the actuator 223.
  • the reference light for reproduction is generated.
  • the reproduction light reproduced by the reproduction reference light propagates through the objective lens 215, the relay lens 213, and the spatial filter 214. Thereafter, the reproduction light passes through the PBS prism 211 and enters the photodetector 225, and the recorded signal can be reproduced.
  • FIGS. 5A to 5C show an operation flow of recording and reproduction in the optical information recording / reproducing apparatus 10.
  • an operation flow relating to recording / reproduction using holography in particular will be described.
  • FIG. 5A shows an operation flow from insertion of the hologram recording medium 1 into the optical information recording / reproducing apparatus 10 until preparation for recording or reproduction is completed, and FIG. 5B records information on the hologram recording medium 1 from the ready state.
  • FIG. 5C shows an operation flow until the information recorded on the hologram recording medium 1 is reproduced from the ready state.
  • the optical information recording / reproducing apparatus 10 discriminates whether or not the inserted medium is a medium for recording or reproducing digital information using holography, for example (see FIG. 5A). 502).
  • the optical information recording / reproducing apparatus 10 reads control data provided on the hologram recording medium (503), For example, information on a hologram recording medium and information on various setting conditions at the time of recording and reproduction are acquired.
  • the operation flow from the ready state to recording of information first receives data to be recorded (511), and sends information corresponding to the data to the spatial light modulator in the pickup 11.
  • a predetermined area is pre-cured using the light beam emitted from the cure optical system 13 (514), and data is recorded using the reference light and signal light emitted from the pickup 11 (515).
  • the data is verified as necessary (516), and post-cure is performed using the light beam emitted from the cure optical system 13 (517).
  • the operation flow from the ready state to the reproduction of recorded information is performed in advance as necessary so that high-quality information can be reproduced from the hologram recording medium (521). ). Thereafter, the position of the pickup 11 and the reproducing reference beam optical system 12 is arranged at a predetermined position of the hologram recording medium by a seek operation (522).
  • the tilt detection of the hologram recording medium of the present invention can be performed in the learning process 504, the data recording 515, or the data reproduction 523.
  • the tilt of the hologram recording medium is adjusted by detecting the tilt of the hologram recording medium of the present invention, and then the tilt of the hologram recording medium or the galvano mirror 219 and the galvano mirror using light diffracted from the hologram. Fine adjustment of the tilt of the mirror 224 may be performed.
  • FIG. 1A and FIG. 1B are diagrams showing the principle for detecting the tilt of the hologram recording medium in the pickup 11.
  • the relay lens 213, the spatial filter 214, and the PBS prism 211 in FIG. 3 and FIG. 4 are omitted, but when these optical components are present, the photodetector 225 will be described in the following description. There is no problem if the image detected in is considered to be inverted.
  • FIG. 1A shows a reference state in which the hologram recording medium 1 is not tilted. It is assumed that when the angle of the reference light is the same as the optical axis of the lens 222, the angle of the reference light reflected by the surface of the hologram recording medium 1 is the same as the optical axis of the objective lens 215. In the case of this relationship, the reference light reflected by the hologram recording medium 1 is condensed on the photodetector 225 by the objective lens 215, and the position where the light is collected is the optical axis position of the objective lens 215.
  • FIG. 1B shows a state where the hologram recording medium 1 is tilted.
  • the angle of the hologram recording medium is shifted by ⁇ from the reference state of FIG. 1A.
  • the reference light passing through the optical axis of the lens 222 is tilted from the optical axis of the objective lens by 2 ⁇ when reflected by the hologram recording medium 1.
  • the description has been made on the assumption that the angle of the reference light reflected when the hologram recording medium is not tilted is the same as the optical axis of the objective lens 215. If there is no inclination, the same inclination can be detected by using the position where the light is focused on the photodetector 225 as a reference.
  • ⁇ x may be calculated using the center of gravity of the bright spot.
  • the reference light that passes through the hologram recording medium 1 is not shown. However, there may be reference light that passes through, and the inclination can be detected if a part of the reference light is reflected.
  • FIG. 6 is a cross-sectional view of the hologram recording medium showing the position at which the reference light used for detecting the tilt of the hologram recording medium is reflected by the hologram recording medium.
  • the hologram recording medium 1 includes a transparent protective layer 601, a recording layer 602, and a transparent protective layer 603, and the reference light passes through the transparent protective layer 601, the recording layer 602, and the transparent protective layer 603 in this order.
  • FIG. 6A shows an example in which the reference light reflected by the surface of the transparent protective layer 601 is used for detecting the tilt of the hologram recording medium.
  • an AR (Anti Reflection) coat is applied to the surface of the transparent protective layer 601, but since the reference light is slightly reflected, the inclination of the hologram recording medium 1 is detected using this reference light. Can do.
  • tilt detection may be performed using reference light reflected by attaching a reflective film to the surface of the transparent protective layer 601 located in an area not used for recording / reproducing or by attaching an AR coat.
  • FIG. 6B shows an example in which a reflective film 604 is disposed at a part of the center of the recording layer 602, and the reference light reflected by the reflective film 604 is used for detecting the tilt of the hologram recording medium.
  • the manufacturing cost of the hologram recording medium 1 is increased, detection using a region close to the hologram recording position can be performed, so that more effective tilt detection can be performed.
  • the inclination of the hologram recording medium 1 is detected using the interface between the transparent protective layer 601 and the recording layer 602, the interface between the recording layer 602 and the transparent protective layer 603, the surface of the transparent protective layer 603, or the like. It is also possible.
  • FIG. 7 is a diagram showing an example of an operation flow for detecting the inclination of the hologram recording medium in the first embodiment.
  • the disk rotation motor control circuit is arranged so that the area to be detected for tilt of the hologram recording medium 1 is arranged in the vicinity of the position where the optical axis of the objective lens 215 and the optical axis of the lens 222 intersect. 88 and the access control circuit 81 (701).
  • the angle of the hologram recording medium 1 is set to the lower limit angle that can be set by the disc tilt control circuit 91 (702).
  • the hologram recording medium 1 is irradiated with reference light at an angle that coincides with the optical axis of the lens 222 (703).
  • the reference light reflected by the hologram recording medium 1 is received by the photodetector 225 (704).
  • the tilt of the hologram recording medium is calculated by the method described in the first embodiment (705).
  • a set angle at which the tilt of the hologram recording medium 1 is minimized is calculated from the relationship between the set angle of the hologram recording medium 1 and the calculated tilt of the hologram recording medium 1, and the disc tilt
  • the setting is made by the control circuit 91 and the processing is terminated (708).
  • the optical information recording / reproducing apparatus 10 can detect the inclination of the hologram recording medium 1 only with a basic configuration necessary for recording / reproducing, and the recording medium once removed from the apparatus is attached again. In this case, it can be reproduced with good quality.
  • the apparatus configuration in the second embodiment is the same as that in the first embodiment.
  • FIG. 8 is a diagram showing an example of an operation flow for detecting the inclination of the hologram recording medium in the second embodiment.
  • the disk rotation motor control circuit is arranged so that the area to be detected for tilt of the hologram recording medium 1 is arranged in the vicinity of the position where the optical axis of the objective lens 215 and the optical axis of the lens 222 intersect. 88 and the access control circuit 81 (801).
  • the reference light is irradiated onto the hologram recording medium 1 at an angle that coincides with the optical axis of the lens 222 (802).
  • the reference light reflected by the hologram recording medium 1 is received by the photodetector 225 (803).
  • the inclination of the hologram recording medium 1 is calculated based on the received information (804).
  • the optical information recording / reproducing apparatus 10 can detect the inclination of the hologram recording medium 1 only with a basic configuration necessary for recording / reproducing, and the recording medium once removed from the apparatus is attached again. In this case, it can be reproduced with good quality. Further, since there is no need to perform a predetermined number of inclination detections, there is an advantage that the processing can be completed in a short time compared to the first embodiment.
  • FIG. 9 is a diagram showing the configuration of the pickup 11 in the third embodiment.
  • the light beam emitted from the light source 901 passes through the collimator lens 902 and enters the shutter 903.
  • the optical element 904 composed of, for example, a half-wave plate or the like adjusts the light quantity ratio of p-polarized light and s-polarized light to a desired ratio.
  • the polarization direction is controlled, the light enters the polarization beam splitter 905.
  • the light beam transmitted through the polarization beam splitter 905 enters the spatial light modulator 908 via the polarization beam splitter 907.
  • the signal light 906 to which information is added by the spatial light modulator 908 is reflected by the polarization beam splitter 907 and propagates through an angle filter 909 that passes only a light beam having a predetermined incident angle. Thereafter, the signal light beam is focused on the hologram recording medium 1 by the objective lens 910.
  • the light beam reflected by the polarization beam splitter 905 acts as reference light 912, and is set to a predetermined polarization direction according to recording or reproduction by the polarization direction conversion element 919, and then passes through the mirror 913 and the mirror 914.
  • the light enters the lens 915.
  • the lens 915 plays a role of condensing the reference light 912 on the back focus surface of the objective lens 910, and the reference light once condensed on the back focus surface of the objective lens 910 is converted again into parallel light by the objective lens 910. Is incident on the hologram recording medium 1.
  • the objective lens 910 or the optical block 921 can be driven in the direction indicated by reference numeral 920, for example, and the objective lens 910 and the objective lens are shifted by shifting the position of the objective lens 910 or the optical block 921 along the driving direction 920. Since the relative positional relationship of the condensing points on the back focus surface 910 changes, the incident angle of the reference light incident on the hologram recording medium 1 can be set to a desired angle. Instead of driving the objective lens 910 or the optical block 921, the incident angle of the reference light may be set to a desired angle by driving the mirror 914 with an actuator.
  • the reference light When reproducing the recorded information, the reference light is incident on the hologram recording medium 1 as described above, and the light beam transmitted through the hologram recording medium 1 is reflected by the galvanometer mirror 916 so that the reproduction reference light is reflected. Generate. The reproduction light reproduced by the reproduction reference light propagates through the objective lens 910 and the angle filter 909. Thereafter, the reproduction light passes through the polarization beam splitter 907 and enters the photodetector 918, and the recorded signal can be reproduced.
  • the optical system shown in FIG. 9 has an advantage that it can be significantly reduced in size as compared with the optical system configuration shown in FIG. 2 by making the signal light and the reference light incident on the same objective lens.
  • FIG. 10A and 10B are diagrams showing the principle for detecting the tilt of the hologram recording medium in the third embodiment in the pickup 11.
  • FIG. 10A shows a reference state in which the hologram recording medium 1 has no inclination.
  • the incident angle of the reference light on the hologram recording medium 1 is ⁇ 0 .
  • the angle formed by the reflected reference light and the optical axis of the objective lens 910 is ⁇ 0 .
  • the reflected reference light is collected by the objective lens 910, passes through the angle filter 909 and the polarization beam splitter 907, and enters the photodetector 918.
  • the distance between the optical axis position of the objective lens 910 focused light is incident on the light detector 918 and x 0.
  • FIG. 10B shows a state where the hologram recording medium 1 is tilted.
  • the angle of the hologram recording medium is shifted by ⁇ from the reference state of FIG. 10A.
  • the reference light having the angle ⁇ 0 is tilted from the optical axis of the objective lens by ⁇ 0 + 2 ⁇ when reflected by the hologram recording medium 1.
  • the operation flow for detecting the tilt of the hologram recording medium in the third embodiment the operation flow used in the first embodiment or the second embodiment can be applied.
  • the apparatus configuration in the fourth embodiment is the same as that in the first embodiment.
  • FIG. 11 is a diagram showing an example of an operation flow for offsetting an angle that is a reference light reference in the fourth embodiment.
  • the disk rotation motor control circuit is arranged so that the area to be detected for tilt of the hologram recording medium 1 is arranged in the vicinity of the position where the optical axis of the objective lens 215 and the optical axis of the lens 222 intersect. 88 and the access control circuit 81 (1101).
  • the reference light is irradiated onto the hologram recording medium 1 at an angle that coincides with the optical axis of the lens 222 (1102).
  • the reference light reflected by the hologram recording medium 1 is received by the photodetector 225 (1103).
  • the inclination of the hologram recording medium 1 is calculated based on the received information (1104).
  • the angle at which the reference light coincides with the optical axis of the lens 222 is used as a reference.
  • the reference angle is offset based on the calculated information on the tilt of the hologram recording medium 1, and the process ends (1105).
  • FIG. 12 is a diagram showing an amount of offsetting the reference angle based on the information on the inclination of the hologram recording medium in the same configuration as in FIGS. 1A and 1B.
  • the optical information recording medium has an inclination ⁇
  • the optical information recording / reproducing apparatus 10 can be configured.
  • the description has been made on the assumption that the tilt information of the hologram recording medium 1 is corrected using the detected information of the tilt of the hologram recording medium 1.
  • the information is not necessarily used for correcting the tilt of the hologram recording medium 1.
  • it may be used for detecting the position of the reproduced image in the photodetector based on the detected tilt information of the hologram recording medium.
  • the operation in the learning process prior to recording and reproduction was explained.
  • the inclination of the same hologram recording medium is detected during recording and reproduction, and the angle of the hologram recording medium is controlled appropriately. It doesn't matter.
  • a part of the reference light reflected by the hologram recording medium 1 can be detected by the photodetector by controlling the polarization state of the reference light. it can.
  • the reproduced data and the reference light reflected by the hologram recording medium 1 are simultaneously detected by the photodetector.
  • a threshold is provided.
  • the inclination detection may be performed by regarding the information of the pixels whose light intensity detected by the photodetector is equal to or greater than the threshold value as the information of the reference light.

Landscapes

  • Optical Recording Or Reproduction (AREA)
  • Optical Head (AREA)
  • Holo Graphy (AREA)
  • Optical Record Carriers And Manufacture Thereof (AREA)

Abstract

The problem addressed by the present invention is having to make an angle of attachment of a recording medium during recording and playback be the same for assuring playback quality when a recording medium on which information is recorded is removed and reattached for playback. In an optical information recording and playback device that plays back information from a hologram recording medium, the position of reference light reflected from a hologram recording medium on a light detector is detected by the light detector, and on the basis of the position information that is detected, the inclination of the hologram recording medium is detected.

Description

ホログラフィックメモリ再生装置、ホログラフィックメモリ再生方法およびホログラム記録媒体Holographic memory reproducing device, holographic memory reproducing method and hologram recording medium 参照による取り込みImport by reference
本出願は、２０１１年９月１６日に出願された日本特許出願第２０１１－２０２５５０号の優先権を主張し、その内容を参照することにより本出願に取り込む。 This application claims the priority of Japanese Patent Application No. 2011-202550 filed on September 16, 2011, and is incorporated herein by reference.
　本発明は、ホログラフィを用いて記録媒体から情報を再生する装置および方法、およびホログラム記録媒体に関する。 The present invention relates to an apparatus and method for reproducing information from a recording medium using holography, and a hologram recording medium.
　現在、青紫色半導体レーザを用いた、Ｂｌｕ－ｒａｙ　Ｄｉｓｃ（ＴＭ）規格により、民生用においても５０ＧＢ程度の記録密度を持つ光ディスクの商品化が可能となってきた。今後は、光ディスクでも１００ＧＢ～１ＴＢというＨＤＤ（Ｈａｒｄ　Ｄｉｓｃ　Ｄｒｉｖｅ）容量と同程度まで大容量化が望まれる。 Currently, the Blu-ray Disc (TM) standard using a blue-violet semiconductor laser has made it possible to commercialize an optical disc having a recording density of about 50 GB even for consumer use. In the future, it is desired to increase the capacity of optical disks to the same level as the HDD (Hard Disc Drive) capacity of 100 GB to 1 TB.
　しかしながら、このような超高密度を光ディスクで実現するためには、短波長化と対物レンズ高ＮＡ化による高密度化技術とは異なる新しい方式による高密度化技術が必要である。 However, in order to realize such an ultra-high density with an optical disk, a high-density technology by a new method different from the high-density technology by shortening the wavelength and increasing the objective lens NA is necessary.
　次世代のストレージ技術に関する研究が行われる中、ホログラフィを利用してデジタル情報を記録するホログラム記録技術が注目を集めている。 While research on next-generation storage technology is underway, hologram recording technology that records digital information using holography is drawing attention.
　ホログラム記録技術とは、空間光変調器により２次元的に変調されたページデータの情報を有する信号光を、記録媒体の内部で参照光と重ね合わせ、その時に生じる干渉縞パターンによって記録媒体内に屈折率変調を生じさせることで情報を記録媒体に記録する技術である。 Hologram recording technology is a method in which signal light having page data information two-dimensionally modulated by a spatial light modulator is superimposed on reference light inside the recording medium, and the interference fringe pattern generated at that time is placed in the recording medium. This is a technique for recording information on a recording medium by causing refractive index modulation.
　情報の再生時には、記録時に用いた参照光を記録媒体に照射すると、記録媒体中に記録されているホログラムが回折格子のように作用して回折光を生じる。この回折光が記録した信号光と位相情報を含めて同一の光として再生される。 When reproducing the information, when the recording medium is irradiated with the reference light used for recording, the hologram recorded in the recording medium acts like a diffraction grating to generate diffracted light. This diffracted light is reproduced as the same light including the recorded signal light and phase information.
　再生された信号光は、ＣＭＯＳやＣＣＤなどの光検出器を用いて２次元的に高速に検出される。このようにホログラム記録技術は、１つのホログラムによって２次元的な情報を一気に光記録媒体に記録し、さらにこの情報を再生することを可能とするものであり、そして、記録媒体のある場所に複数のページデータを重ね書きすることができるため、大容量かつ高速な情報の記録再生を果たすことができる。 Regenerated signal light is detected two-dimensionally at high speed using a photodetector such as a CMOS or CCD. As described above, the hologram recording technique enables two-dimensional information to be recorded on the optical recording medium at once by one hologram and further reproduces this information. Since the page data can be overwritten, large-capacity and high-speed information recording / reproduction can be achieved.
　特開２００７－２５６９４９（特許文献１）には「ホログラフィックメモリ媒体に、ラジアルチルト方向の基準入射角度を規定するための基準チルトホログラムを記録しておく。記録／再生動作時には、まず、基準チルトホログラムの記録位置に参照光を照射し、その受光状態から、ラジアルチルト方向における参照光の基準入射角度（基準角度Ｓｒ）を検出する。そして、ホログラフィックメモリ媒体をラジアルチルト方向に変位させるチルトアクチュエータ１９を駆動制御して、参照光のラジアルチルト方向の入射角度を基準角度Ｓｒに整合させる。しかる後、ホログラフィックメモリ媒体に信号光および参照光を照射して、記録／再生動作を実行する。」（要約）が記載されている。 Japanese Patent Application Laid-Open No. 2007-256949 (Patent Document 1) states that “a reference tilt hologram for defining a reference incident angle in the radial tilt direction is recorded in a holographic memory medium. Reference light is irradiated to the hologram recording position, and the reference incident angle (reference angle Sr) of the reference light in the radial tilt direction is detected from the light receiving state, and a tilt actuator that displaces the holographic memory medium in the radial tilt direction The incident angle of the reference light in the radial tilt direction is matched with the reference angle Sr by driving and controlling 19. Then, the holographic memory medium is irradiated with the signal light and the reference light to execute the recording / reproducing operation. (Summary).
特開２００７－２５６９４９JP2007-256949A
　情報が記録された記録媒体を装置から取り外し、再度取り付けた場合に再生品質が劣化するという問題があった。原因の一つとして記録媒体を再度取り付けた場合に記録時の記録媒体の取り付け角度からずれてしまっていることが挙げられる。このため、記録時と再生時とで記録媒体の取り付け角度を一致させなければならないという課題があった。 There was a problem that the reproduction quality deteriorated when the recording medium on which the information was recorded was removed from the apparatus and attached again. One of the causes is that when the recording medium is attached again, the recording medium is deviated from the attachment angle at the time of recording. For this reason, there has been a problem that the mounting angle of the recording medium has to be matched between recording and reproduction.
　しかしながら、特許文献１の従来技術の場合、基準チルトホログラムを記録する必要があり、これを記録媒体の製造業者で行う場合はコストの増大のおそれがある。また、ユーザが行う場合は基準チルトのホログラムが記録される際に記録媒体に傾きがあると傾いた状態が基準となるおそれがある。 However, in the case of the prior art of Patent Document 1, it is necessary to record the reference tilt hologram, and if this is performed by the manufacturer of the recording medium, the cost may increase. In addition, when the user performs the recording, if the recording medium is tilted when the reference tilt hologram is recorded, the tilted state may become the reference.
　本発明の目的は、基準となるホログラムや追加の装置構成を用いずとも記録媒体の傾きを検出する手段を提供することにより、一度装置から取り外した記録媒体を再度取り付けた場合に良好な品質で再生可能とすることにある。 The object of the present invention is to provide a means for detecting the tilt of a recording medium without using a reference hologram or an additional apparatus configuration, so that the recording medium once removed from the apparatus has a good quality when it is reattached. It is to be reproducible.
　上記課題は、例えば請求項の範囲に記載の発明により解決される。 The above problem is solved by, for example, the invention described in the scope of claims.
　本発明によれば、基準となるホログラムや追加の装置構成を用いずに記録媒体の傾きを検出することが可能となり、一度装置から取り外した記録媒体を再度取り付けた場合に良好な品質で再生可能となる。
　本発明の他の目的、特徴及び利点は添付図面に関する以下の本発明の実施例の記載から明らかになるであろう。 According to the present invention, it is possible to detect the tilt of a recording medium without using a reference hologram or an additional apparatus configuration, and it is possible to reproduce with good quality when a recording medium once removed from the apparatus is mounted again. It becomes.
Other objects, features and advantages of the present invention will become apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.
ホログラム記録媒体の傾きを検出するための原理を示した図Diagram showing the principle for detecting the tilt of a hologram recording medium ホログラム記録媒体の傾きを検出するための原理を示した図Diagram showing the principle for detecting the tilt of a hologram recording medium 光情報記録再生装置の実施例を表す概略図Schematic diagram showing an embodiment of an optical information recording / reproducing apparatus 光情報記録再生装置内のピックアップの実施例を表す概略図Schematic showing an embodiment of a pickup in an optical information recording / reproducing apparatus 光情報記録再生装置内のピックアップの実施例を表す概略図Schematic showing an embodiment of a pickup in an optical information recording / reproducing apparatus 光情報記録再生装置の動作フローの実施例を表す概略図Schematic showing an embodiment of the operation flow of the optical information recording / reproducing apparatus 光情報記録再生装置の動作フローの実施例を表す概略図Schematic showing an embodiment of the operation flow of the optical information recording / reproducing apparatus 光情報記録再生装置の動作フローの実施例を表す概略図Schematic showing an embodiment of the operation flow of the optical information recording / reproducing apparatus ホログラム記録媒体の傾きを検出するために用いる参照光がホログラム記録媒体で反射する位置を示した図The figure which showed the position where the reference light used in order to detect the inclination of a hologram recording medium reflects in a hologram recording medium ホログラム記録媒体の傾きを検出するために用いる参照光がホログラム記録媒体で反射する位置を示した図The figure which showed the position where the reference light used in order to detect the inclination of a hologram recording medium reflects in a hologram recording medium 第１の実施例におけるホログラム記録媒体の傾き検出を行うための動作フローの一例を示した図The figure which showed an example of the operation | movement flow for performing the inclination detection of the hologram recording medium in 1st Example 第２の実施例におけるホログラム記録媒体の傾き検出を行うための動作フローの一例を示した図The figure which showed an example of the operation | movement flow for performing the inclination detection of the hologram recording medium in 2nd Example 第３の実施例におけるピックアップの構成を示した図The figure which showed the structure of the pick-up in a 3rd Example. 第３の実施例におけるホログラム記録媒体の傾きを検出するための原理を示した図The figure which showed the principle for detecting the inclination of the hologram recording medium in 3rd Example 第３の実施例におけるホログラム記録媒体の傾きを検出するための原理を示した図The figure which showed the principle for detecting the inclination of the hologram recording medium in 3rd Example 第４の実施例において参照光の基準となる角度をオフセットさせるための動作フローの一例を示した図The figure which showed an example of the operation | movement flow for offsetting the angle used as the reference | standard of reference light in 4th Example 基準となる角度をオフセットさせる量を示した図Diagram showing the amount to offset the reference angle
　以下、本発明の実施例について説明する。 Hereinafter, examples of the present invention will be described.
　本発明の実施形態を添付図面にしたがって説明する。図２はホログラフィを利用してデジタル情報を記録および／または再生するホログラム記録媒体の記録再生装置を示すブロック図である。 Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 2 is a block diagram showing a recording / reproducing apparatus for a hologram recording medium for recording and / or reproducing digital information using holography.
　光情報記録再生装置１０は、ピックアップ１１、再生用参照光光学系１２、キュア光学系１３、ディスク回転角度検出用光学系１４、回転モータ５０、およびディスクチルト機構９０を備えており、ホログラム記録媒体１は回転モータ５０によって回転することと、ディスクチルト機構９０によって傾きを補正することが可能な構成となっている。 The optical information recording / reproducing apparatus 10 includes a pickup 11, a reproducing reference light optical system 12, a cure optical system 13, a disk rotation angle detecting optical system 14, a rotation motor 50, and a disk tilt mechanism 90, and a hologram recording medium. 1 is configured to be rotated by the rotary motor 50 and to correct the tilt by the disc tilt mechanism 90.
　ピックアップ１１は、参照光と信号光をホログラム記録媒体１に出射してホログラフィを利用してデジタル情報を記録媒体に記録する役割を果たす。この際、記録する情報信号はコントローラ８９によって信号生成回路８６を介してピックアップ１１内の空間光変調器に送り込まれ、信号光は空間光変調器によって変調される。 The pickup 11 plays a role of emitting reference light and signal light to the hologram recording medium 1 and recording digital information on the recording medium using holography. At this time, the information signal to be recorded is sent by the controller 89 to the spatial light modulator in the pickup 11 via the signal generation circuit 86, and the signal light is modulated by the spatial light modulator.
　ホログラム記録媒体１に記録した情報を再生する場合は、ピックアップ１１から出射された参照光を記録時とは逆の向きにホログラム記録媒体に入射させる光波を再生用参照光光学系１２にて生成する。再生用参照光によって再生される再生光をピックアップ１１内の後述する光検出器によって検出し、信号処理回路８５によって信号を再生する。 When the information recorded on the hologram recording medium 1 is reproduced, the reproduction reference light optical system 12 generates a light wave that causes the reference light emitted from the pickup 11 to enter the hologram recording medium in a direction opposite to that at the time of recording. . Reproduction light reproduced by the reproduction reference light is detected by a photodetector (to be described later) in the pickup 11, and a signal is reproduced by the signal processing circuit 85.
　ホログラム記録媒体１に照射する参照光と信号光の照射時間は、ピックアップ１１内のシャッタの開閉時間をコントローラ８９によってシャッタ制御回路８７を介して制御することで調整できる。 The irradiation time of the reference light and the signal light applied to the hologram recording medium 1 can be adjusted by controlling the opening / closing time of the shutter in the pickup 11 by the controller 89 via the shutter control circuit 87.
　キュア光学系１３は、ホログラム記録媒体１のプリキュアおよびポストキュアに用いる光ビームを生成する役割を果たす。プリキュアとは、ホログラム記録媒体１内の所望の位置に情報を記録する際、所望位置に参照光と信号光を照射する前に予め所定の光ビームを照射する前工程である。ポストキュアとは、ホログラム記録媒体１内の所望の位置に情報を記録した後、該所望の位置に追記不可能とするために所定の光ビームを照射する後工程である。 The cure optical system 13 plays a role of generating a light beam used for pre-cure and post-cure of the hologram recording medium 1. Pre-curing is a pre-process for irradiating a predetermined light beam in advance before irradiating the reference light and signal light to the desired position when recording information at the desired position in the hologram recording medium 1. Post-cure is a post-process for irradiating a predetermined light beam after recording information at a desired position in the hologram recording medium 1 so that additional recording cannot be performed at the desired position.
　ディスク回転角度検出用光学系１４は、ホログラム記録媒体１の回転角度を検出するために用いられる。ホログラム記録媒体１を所定の回転角度に調整する場合は、ディスク回転角度検出用光学系１４によって回転角度に応じた信号を検出し、検出された信号を用いてコントローラ８９によってディスク回転モータ制御回路８８を介してホログラム記録媒体１の回転角度を制御する事が出来る。 The disk rotation angle detection optical system 14 is used to detect the rotation angle of the hologram recording medium 1. When the hologram recording medium 1 is adjusted to a predetermined rotation angle, a signal corresponding to the rotation angle is detected by the disk rotation angle detection optical system 14, and the disk rotation motor control circuit 88 is detected by the controller 89 using the detected signal. The rotation angle of the hologram recording medium 1 can be controlled via
　ホログラム記録媒体１を所定の傾きに調整するために、後述する記録媒体の角度検出を行い、検出した信号を用いてコントローラ８９によってディスクチルト制御回路９１を介してディスクチルト機構９０を駆動することでホログラム記録媒体１の傾きを制御することができる。 In order to adjust the hologram recording medium 1 to a predetermined inclination, the angle of the recording medium, which will be described later, is detected, and the disc tilt mechanism 90 is driven by the controller 89 via the disc tilt control circuit 91 using the detected signal. The inclination of the hologram recording medium 1 can be controlled.
　光源駆動回路８２からは所定の光源駆動電流がピックアップ１１、キュア光学系１３、ディスク回転角度検出用光学系１４内の光源に供給され、各々の光源からは所定の光量で光ビームを発光することができる。 A predetermined light source driving current is supplied from the light source driving circuit 82 to the light sources in the pickup 11, the cure optical system 13, and the disk rotation angle detection optical system 14, and each light source emits a light beam with a predetermined light amount. Can do.
　また、ピックアップ１１、そして、ディスクキュア光学系１３は、ホログラム記録媒体１の半径方向に位置をスライドできる機構が設けられており、アクセス制御回路８１を介して位置制御がおこなわれる。 Further, the pickup 11 and the disc cure optical system 13 are provided with a mechanism capable of sliding the position in the radial direction of the hologram recording medium 1, and the position is controlled via the access control circuit 81.
　ところで、ホログラフィの角度多重の原理を利用した記録技術は、参照光角度のずれに対する許容誤差が極めて小さくなる傾向がある。 By the way, the recording technique using the principle of angle multiplexing of holography tends to have a very small tolerance for the deviation of the reference beam angle.
　従って、ピックアップ１１内に、参照光角度のずれ量を検出する機構を設けて、サーボ信号生成回路８３にてサーボ制御用の信号を生成し、サーボ制御回路８４を介して該ずれ量を補正するためのサーボ機構を光情報記録再生装置１０内に備えることが必要となる。 Therefore, a mechanism for detecting the deviation amount of the reference beam angle is provided in the pickup 11, a servo control signal is generated by the servo signal generation circuit 83, and the deviation amount is corrected via the servo control circuit 84. It is necessary to provide a servo mechanism for this purpose in the optical information recording / reproducing apparatus 10.
　また、ピックアップ１１、キュア光学系１３、ディスク回転角度検出用光学系１４は、いくつかの光学系構成または全ての光学系構成をひとつに纏めて簡素化しても構わない。 Further, the pickup 11, the cure optical system 13, and the disk rotation angle detection optical system 14 may be simplified by combining several optical system configurations or all optical system configurations into one.
　図３は、光情報記録再生装置１０におけるピックアップ１１の基本的な光学系構成の一例における記録原理を示したものである。光源２０１を出射した光ビームはコリメートレンズ２０２を透過し、シャッタ２０３に入射する。シャッタ２０３が開いている時は、光ビームはシャッタ２０３を通過した後、例えば２分の１波長板などで構成される光学素子２０４によってｐ偏光とｓ偏光の光量比が所望の比になるようになど偏光方向が制御された後、ＰＢＳ（Ｐｏｌａｒｉｚａｔｉｏｎ　Ｂｅａｍ　Ｓｐｌｉｔｔｅｒ）プリズム２０５に入射する。 FIG. 3 shows a recording principle in an example of a basic optical system configuration of the pickup 11 in the optical information recording / reproducing apparatus 10. The light beam emitted from the light source 201 passes through the collimator lens 202 and enters the shutter 203. When the shutter 203 is open, after the light beam passes through the shutter 203, the optical element 204 composed of, for example, a half-wave plate or the like, adjusts the light quantity ratio of p-polarized light and s-polarized light to a desired ratio. After the polarization direction is controlled, the light beam enters a PBS (Polarization Beam Splitter) prism 205.
　ＰＢＳプリズム２０５を透過した光ビームは、信号光２０６として働き、ビームエキスパンダ２０８によって光ビーム径が拡大された後、位相マスク２０９、リレーレンズ２１０、ＰＢＳプリズム２１１を透過して空間光変調器２１２に入射する。 The light beam that has passed through the PBS prism 205 functions as signal light 206, and after the light beam diameter is expanded by the beam expander 208, the light beam passes through the phase mask 209, the relay lens 210, and the PBS prism 211 and passes through the spatial light modulator 212. Is incident on.
　空間光変調器２１２によって情報が付加された信号光は、ＰＢＳプリズム２１１を反射し、リレーレンズ２１３ならびに空間フィルタ２１４を伝播する。その後、信号光は対物レンズ２１５によってホログラム記録媒体１に集光する。 The signal light to which information is added by the spatial light modulator 212 reflects the PBS prism 211 and propagates through the relay lens 213 and the spatial filter 214. Thereafter, the signal light is condensed on the hologram recording medium 1 by the objective lens 215.
　一方、ＰＢＳプリズム２０５を反射した光ビームは参照光２０７として働き、偏光方向変換素子２１６によって記録時または再生時に応じて所定の偏光方向に設定された後、ミラー２１７ならびにミラー２１８を経由してガルバノミラー２１９に入射する。ガルバノミラー２１９はアクチュエータ２２０によって角度を調整可能のため、レンズ２２１とレンズ２２２を通過した後にホログラム記録媒体１に入射する参照光の入射角度を、所望の角度に設定することができる。なお、参照光の入射角度を設定するために、ガルバノミラーに代えて、参照光の波面を変換する素子を用いても構わない。 On the other hand, the light beam reflected by the PBS prism 205 works as reference light 207, and is set to a predetermined polarization direction according to recording or reproduction by the polarization direction conversion element 216, and then galvanically passed through the mirror 217 and the mirror 218. Incident on the mirror 219. Since the angle of the galvanometer mirror 219 can be adjusted by the actuator 220, the incident angle of the reference light incident on the hologram recording medium 1 after passing through the lens 221 and the lens 222 can be set to a desired angle. In order to set the incident angle of the reference light, an element that converts the wavefront of the reference light may be used instead of the galvanometer mirror.
　このように信号光と参照光とをホログラム記録媒体１において、互いに重ね合うように入射させることで、記録媒体内には干渉縞パターンが形成され、このパターンを記録媒体に書き込むことで情報を記録する。また、ガルバノミラー２１９によってホログラム記録媒体１に入射する参照光の入射角度を変化させることができるため、角度多重による記録が可能である。 In this way, the signal light and the reference light are incident on the hologram recording medium 1 so as to overlap each other, whereby an interference fringe pattern is formed in the recording medium, and information is recorded by writing this pattern on the recording medium. . In addition, since the incident angle of the reference light incident on the hologram recording medium 1 can be changed by the galvanometer mirror 219, recording by angle multiplexing is possible.
　以降、同じ領域に参照光角度を変えて記録されたホログラムにおいて、１つ１つの参照光角度に対応したホログラムをページと呼び、同領域に角度多重されたページの集合をブックと呼ぶことにする。 Hereinafter, in holograms recorded in the same area with different reference beam angles, holograms corresponding to each reference beam angle are called pages, and a set of pages angle-multiplexed in the same area is called a book. .
　図４は、光情報記録再生装置１０におけるピックアップ１１の基本的な光学系構成の一例における再生原理を示したものである。記録した情報を再生する場合は、前述したように参照光をホログラム記録媒体１に入射し、ホログラム記録媒体１を透過した光ビームを、アクチュエータ２２３によって角度調整可能なガルバノミラー２２４にて反射させることで、その再生用参照光を生成する。 FIG. 4 shows a reproduction principle in an example of a basic optical system configuration of the pickup 11 in the optical information recording / reproducing apparatus 10. When reproducing the recorded information, the reference beam is incident on the hologram recording medium 1 as described above, and the light beam transmitted through the hologram recording medium 1 is reflected by the galvanometer mirror 224 whose angle can be adjusted by the actuator 223. Thus, the reference light for reproduction is generated.
　この再生用参照光によって再生された再生光は、対物レンズ２１５、リレーレンズ２１３ならびに空間フィルタ２１４を伝播する。その後、再生光はＰＢＳプリズム２１１を透過して光検出器２２５に入射し、記録した信号を再生することができる。 The reproduction light reproduced by the reproduction reference light propagates through the objective lens 215, the relay lens 213, and the spatial filter 214. Thereafter, the reproduction light passes through the PBS prism 211 and enters the photodetector 225, and the recorded signal can be reproduced.
　図５Ａ－５Ｃは、光情報記録再生装置１０における記録、再生の動作フローを示したものである。ここでは、特にホログラフィを利用した記録再生に関する動作フローを説明する。 FIGS. 5A to 5C show an operation flow of recording and reproduction in the optical information recording / reproducing apparatus 10. Here, an operation flow relating to recording / reproduction using holography in particular will be described.
　図５Ａは、光情報記録再生装置１０にホログラム記録媒体１を挿入した後、記録または再生の準備が完了するまでの動作フローを示し、図５Ｂは準備完了状態からホログラム記録媒体１に情報を記録するまでの動作フロー、図５Ｃは準備完了状態からホログラム記録媒体１に記録した情報を再生するまでの動作フローを示したものである。 FIG. 5A shows an operation flow from insertion of the hologram recording medium 1 into the optical information recording / reproducing apparatus 10 until preparation for recording or reproduction is completed, and FIG. 5B records information on the hologram recording medium 1 from the ready state. FIG. 5C shows an operation flow until the information recorded on the hologram recording medium 1 is reproduced from the ready state.
　図５Ａに示すように媒体を挿入すると（５０１）、光情報記録再生装置１０は、例えば挿入された媒体がホログラフィを利用してデジタル情報を記録または再生する媒体であるかどうかディスク判別を行う（５０２）。 When a medium is inserted as shown in FIG. 5A (501), the optical information recording / reproducing apparatus 10 discriminates whether or not the inserted medium is a medium for recording or reproducing digital information using holography, for example (see FIG. 5A). 502).
　ディスク判別の結果、ホログラフィを利用してデジタル情報を記録または再生するホログラム記録媒体であると判断されると、光情報記録再生装置１０はホログラム記録媒体に設けられたコントロールデータを読み出し（５０３）、例えばホログラム記録媒体に関する情報や、例えば記録や再生時における各種設定条件に関する情報を取得する。 As a result of disc discrimination, when it is determined that the hologram recording medium records or reproduces digital information using holography, the optical information recording / reproducing apparatus 10 reads control data provided on the hologram recording medium (503), For example, information on a hologram recording medium and information on various setting conditions at the time of recording and reproduction are acquired.
　コントロールデータの読み出し後は、コントロールデータに応じた各種調整やピックアップ１１に関わる学習処理（５０４）を行い、光情報記録再生装置１０は、記録または再生の準備が完了する（５０５）。 After reading out the control data, various adjustments according to the control data and learning processing (504) related to the pickup 11 are performed, and the optical information recording / reproducing apparatus 10 is ready for recording or reproduction (505).
　準備完了状態から情報を記録するまでの動作フローは図５Ｂに示すように、まず記録するデータを受信して（５１１）、該データに応じた情報をピックアップ１１内の空間光変調器に送り込む。 As shown in FIG. 5B, the operation flow from the ready state to recording of information first receives data to be recorded (511), and sends information corresponding to the data to the spatial light modulator in the pickup 11.
　その後、ホログラム記録媒体に高品質の情報を記録できるように、必要に応じて各種学習処理を事前に行い（５１２）、シーク動作（５１３）によりピックアップ１１ならびにキュア光学系１３の位置をホログラム記録媒体の所定の位置に配置する。 Thereafter, various learning processes are performed in advance as necessary so that high-quality information can be recorded on the hologram recording medium (512), and the positions of the pickup 11 and the cure optical system 13 are determined by the seek operation (513). Arranged at a predetermined position.
　その後、キュア光学系１３から出射する光ビームを用いて所定の領域をプリキュアし（５１４）、ピックアップ１１から出射する参照光と信号光を用いてデータを記録する（５１５）。 Thereafter, a predetermined area is pre-cured using the light beam emitted from the cure optical system 13 (514), and data is recorded using the reference light and signal light emitted from the pickup 11 (515).
　データを記録した後は、必要に応じてデータをベリファイし（５１６）、キュア光学系１３から出射する光ビームを用いてポストキュアを行う（５１７）。 After recording the data, the data is verified as necessary (516), and post-cure is performed using the light beam emitted from the cure optical system 13 (517).
　準備完了状態から記録された情報を再生するまでの動作フローは図５Ｃに示すように、ホログラム記録媒体から高品質の情報を再生できるように、必要に応じて各種学習処理を事前に行う（５２１）。その後、シーク動作（５２２）によりピックアップ１１ならびに再生用参照光光学系１２の位置をホログラム記録媒体の所定の位置に配置する。 As shown in FIG. 5C, the operation flow from the ready state to the reproduction of recorded information is performed in advance as necessary so that high-quality information can be reproduced from the hologram recording medium (521). ). Thereafter, the position of the pickup 11 and the reproducing reference beam optical system 12 is arranged at a predetermined position of the hologram recording medium by a seek operation (522).
　その後、ピックアップ１１から参照光を出射し、ホログラム記録媒体に記録された情報を読み出す（５２３）。 Thereafter, reference light is emitted from the pickup 11 to read out information recorded on the hologram recording medium (523).
　本発明のホログラム記録媒体の傾き検出は学習処理５０４、もしくはデータ記録５１５、もしくはデータ再生５２３の中で行うことが可能である。 The tilt detection of the hologram recording medium of the present invention can be performed in the learning process 504, the data recording 515, or the data reproduction 523.
　なお、データ再生の場合には本発明のホログラム記録媒体の傾き検出によりホログラム記録媒体の傾き調整を行った後に、さらにホログラムから回折される光を用いてホログラム記録媒体の傾きもしくはガルバノミラー２１９およびガルバノミラー２２４の傾きの微調整を行っても構わない。 In the case of data reproduction, the tilt of the hologram recording medium is adjusted by detecting the tilt of the hologram recording medium of the present invention, and then the tilt of the hologram recording medium or the galvano mirror 219 and the galvano mirror using light diffracted from the hologram. Fine adjustment of the tilt of the mirror 224 may be performed.
　図１Ａ、図１Ｂはピックアップ１１において、ホログラム記録媒体の傾きを検出するための原理を示した図である。ここで、図３および図４におけるリレーレンズ２１３、空間フィルタ２１４、およびＰＢＳプリズム２１１は省略して図示しているが、これらの光学部品があった場合には、以降の説明において光検出器２２５で検出される像が反転するものとして考えれば問題ない。 FIG. 1A and FIG. 1B are diagrams showing the principle for detecting the tilt of the hologram recording medium in the pickup 11. Here, the relay lens 213, the spatial filter 214, and the PBS prism 211 in FIG. 3 and FIG. 4 are omitted, but when these optical components are present, the photodetector 225 will be described in the following description. There is no problem if the image detected in is considered to be inverted.
　図１Ａはホログラム記録媒体１に傾きが無い基準の状態を示す。参照光の角度がレンズ２２２の光軸と同一である場合に、ホログラム記録媒体１の表面で反射した参照光の角度が対物レンズ２１５の光軸と同一となる関係にあるものとする。この関係の場合、ホログラム記録媒体１で反射した参照光は対物レンズ２１５により光検出器２２５に集光し、集光する位置は対物レンズ２１５の光軸位置となる。 FIG. 1A shows a reference state in which the hologram recording medium 1 is not tilted. It is assumed that when the angle of the reference light is the same as the optical axis of the lens 222, the angle of the reference light reflected by the surface of the hologram recording medium 1 is the same as the optical axis of the objective lens 215. In the case of this relationship, the reference light reflected by the hologram recording medium 1 is condensed on the photodetector 225 by the objective lens 215, and the position where the light is collected is the optical axis position of the objective lens 215.
　図１Ｂはホログラム記録媒体１に傾きがある場合の状態を示す。図１Ｂではホログラム記録媒体の角度が図１Ａの基準状態からΔθだけずれているものとする。このとき、レンズ２２２の光軸を通る参照光はホログラム記録媒体１で反射した際に２Δθだけ対物レンズの光軸から傾く。対物レンズ２１５の焦点距離をｆとして光軸から２Δθだけ傾いた参照光が光検出器で光軸からΔｘだけずれて集光する場合に、一例としてΔｘ＝ｆ・ｓｉｎ２Δθの関係となっているものとする。このとき、Δθ＝｛ｓｉｎ-１（Δｘ／ｆ）｝／２であるため、集光した光の位置を光検出器２２５で検出して算出したΔｘを用いて、ホログラム記録媒体１の基準状態からの角度ずれ量を算出することができる。 FIG. 1B shows a state where the hologram recording medium 1 is tilted. In FIG. 1B, it is assumed that the angle of the hologram recording medium is shifted by Δθ from the reference state of FIG. 1A. At this time, the reference light passing through the optical axis of the lens 222 is tilted from the optical axis of the objective lens by 2Δθ when reflected by the hologram recording medium 1. When reference light tilted by 2Δθ from the optical axis with the focal length of the objective lens 215 as f is condensed by a photodetector with a deviation of Δx from the optical axis, for example, a relationship of Δx = f · sin2Δθ And At this time, since Δθ = {sin −1 (Δx / f)} / 2, the reference state of the hologram recording medium 1 is calculated using Δx calculated by detecting the position of the condensed light with the photodetector 225. The amount of angular deviation from the angle can be calculated.
　なお、ここでは、ホログラム記録媒体の傾きが無い場合に反射した参照光の角度が対物レンズ２１５の光軸と同一であるものとして説明を行ったが、必ずしも同一である必要は無く、ホログラム記録媒体の傾きが無い場合に光検出器２２５に集光する位置を基準とすれば同様の傾き検出が可能である。 Here, the description has been made on the assumption that the angle of the reference light reflected when the hologram recording medium is not tilted is the same as the optical axis of the objective lens 215. If there is no inclination, the same inclination can be detected by using the position where the light is focused on the photodetector 225 as a reference.
　なお、光検出器２２５に集光した参照光は光検出器２２５の複数の画素に跨った輝点となる場合には、輝点の重心を用いてΔｘを算出すれば良い。 In addition, when the reference light condensed on the photodetector 225 becomes a bright spot straddling a plurality of pixels of the photodetector 225, Δx may be calculated using the center of gravity of the bright spot.
　なお、図５ではホログラム記録媒体１を透過する参照光は図示していないが、透過する参照光があても構わなく、参照光の一部が反射すれば傾き検出が可能である。 In FIG. 5, the reference light that passes through the hologram recording medium 1 is not shown. However, there may be reference light that passes through, and the inclination can be detected if a part of the reference light is reflected.
　図６はホログラム記録媒体の傾きを検出するために用いる参照光がホログラム記録媒体で反射する位置をホログラム記録媒体の断面で示した図である。ホログラム記録媒体１は透明保護層６０１、記録層６０２、透明保護層６０３から構成され、参照光は透明保護層６０１、記録層６０２、透明保護層６０３の順に透過するものとする。 FIG. 6 is a cross-sectional view of the hologram recording medium showing the position at which the reference light used for detecting the tilt of the hologram recording medium is reflected by the hologram recording medium. The hologram recording medium 1 includes a transparent protective layer 601, a recording layer 602, and a transparent protective layer 603, and the reference light passes through the transparent protective layer 601, the recording layer 602, and the transparent protective layer 603 in this order.
　図６Ａは透明保護層６０１の表面で反射した参照光をホログラム記録媒体の傾き検出に利用する例である。通常、不要反射を防止するためＡＲ（Ａｎｔｉ　Ｒｅｆｌｅｃｔｉｏｎ）コートを透明保護層６０１の表面に付けるが、僅かに参照光は反射するため、この参照光を用いてホログラム記録媒体１の傾き検出を行うことができる。また、記録再生には用いない領域に位置する透明保護層６０１の表面に反射膜を付ける、もしくはＡＲコートを付けないことによって反射させた参照光を用いて傾き検出を行っても良い。 FIG. 6A shows an example in which the reference light reflected by the surface of the transparent protective layer 601 is used for detecting the tilt of the hologram recording medium. Usually, in order to prevent unnecessary reflection, an AR (Anti Reflection) coat is applied to the surface of the transparent protective layer 601, but since the reference light is slightly reflected, the inclination of the hologram recording medium 1 is detected using this reference light. Can do. In addition, tilt detection may be performed using reference light reflected by attaching a reflective film to the surface of the transparent protective layer 601 located in an area not used for recording / reproducing or by attaching an AR coat.
　図６Ｂは記録層６０２の中央の一部に反射膜６０４を配置し、反射膜６０４で反射した参照光をホログラム記録媒体の傾き検出に利用する例である。ホログラム記録媒体１の製造コストが上がるものの、ホログラム記録位置に近い領域を用いた検出が行えるため、より効果の高い傾き検出を行うことができる。 FIG. 6B shows an example in which a reflective film 604 is disposed at a part of the center of the recording layer 602, and the reference light reflected by the reflective film 604 is used for detecting the tilt of the hologram recording medium. Although the manufacturing cost of the hologram recording medium 1 is increased, detection using a region close to the hologram recording position can be performed, so that more effective tilt detection can be performed.
　なお、この他にも透明保護層６０１と記録層６０２との界面、記録層６０２と透明保護層６０３との界面、もしくは透明保護層６０３の表面等を用いてホログラム記録媒体１の傾き検出を行うことも可能である。 In addition, the inclination of the hologram recording medium 1 is detected using the interface between the transparent protective layer 601 and the recording layer 602, the interface between the recording layer 602 and the transparent protective layer 603, the surface of the transparent protective layer 603, or the like. It is also possible.
　図７は第１の実施例におけるホログラム記録媒体の傾き検出を行うための動作フローの一例を示した図である。処理が開始されると、まずホログラム記録媒体１の傾き検出の対象となる領域が対物レンズ２１５の光軸とレンズ２２２の光軸の交差する位置の近傍に配置されるようにディスク回転モータ制御回路８８とアクセス制御回路８１を用いて制御する（７０１）。次にディスクチルト制御回路９１により設定可能な下限の角度にホログラム記録媒体１の角度を設定する（７０２）。次に参照光をレンズ２２２の光軸と一致する角度でホログラム記録媒体１に照射する（７０３）。次にホログラム記録媒体１で反射した参照光を光検出器２２５で受光する（７０４）。次に受光した情報を基に、第１の実施例で記述した方法でホログラム記録媒体の傾きを算出する（７０５）。次にディスクチルト制御回路９１の設定角度が設定可能な上限の角度より大きいか判断を行う（７０６）。７０６で上限の角度以下であれば、ホログラム記録媒体１の傾きをディスクチルト制御回路により所定量増加させる（７０７）。７０６で上限の角度より大きい場合は、設定したホログラム記録媒体１の角度と算出されたホログラム記録媒体１の傾きとの関係からホログラム記録媒体１の傾きが最小となる設定角度を算出し、ディスクチルト制御回路９１により設定し処理を終了する（７０８）。 FIG. 7 is a diagram showing an example of an operation flow for detecting the inclination of the hologram recording medium in the first embodiment. When the processing is started, first, the disk rotation motor control circuit is arranged so that the area to be detected for tilt of the hologram recording medium 1 is arranged in the vicinity of the position where the optical axis of the objective lens 215 and the optical axis of the lens 222 intersect. 88 and the access control circuit 81 (701). Next, the angle of the hologram recording medium 1 is set to the lower limit angle that can be set by the disc tilt control circuit 91 (702). Next, the hologram recording medium 1 is irradiated with reference light at an angle that coincides with the optical axis of the lens 222 (703). Next, the reference light reflected by the hologram recording medium 1 is received by the photodetector 225 (704). Next, based on the received information, the tilt of the hologram recording medium is calculated by the method described in the first embodiment (705). Next, it is determined whether the set angle of the disc tilt control circuit 91 is larger than a settable upper limit angle (706). If the angle is equal to or smaller than the upper limit angle at 706, the tilt of the hologram recording medium 1 is increased by a predetermined amount by the disc tilt control circuit (707). When the angle is larger than the upper limit angle at 706, a set angle at which the tilt of the hologram recording medium 1 is minimized is calculated from the relationship between the set angle of the hologram recording medium 1 and the calculated tilt of the hologram recording medium 1, and the disc tilt The setting is made by the control circuit 91 and the processing is terminated (708).
　本実施例によれば、光情報記録再生装置１０において記録再生に必要な基本的な構成のみでホログラム記録媒体１の傾きを検出することが可能であり、一度装置から取り外した記録媒体を再度取り付けた場合に良好な品質で再生可能となる。 According to the present embodiment, the optical information recording / reproducing apparatus 10 can detect the inclination of the hologram recording medium 1 only with a basic configuration necessary for recording / reproducing, and the recording medium once removed from the apparatus is attached again. In this case, it can be reproduced with good quality.
　第２の実施例における装置構成は第１の実施例と同様である。 The apparatus configuration in the second embodiment is the same as that in the first embodiment.
　図８は第２の実施例におけるホログラム記録媒体の傾き検出を行うための動作フローの一例を示した図である。処理が開始されると、まずホログラム記録媒体１の傾き検出の対象となる領域が対物レンズ２１５の光軸とレンズ２２２の光軸の交差する位置の近傍に配置されるようにディスク回転モータ制御回路８８とアクセス制御回路８１を用いて制御する（８０１）。次に参照光がレンズ２２２の光軸と一致する角度でホログラム記録媒体１に照射する（８０２）。次にホログラム記録媒体１で反射した参照光を光検出器２２５で受光する（８０３）。次に受光した情報を基に、ホログラム記録媒体１の傾きを算出する（８０４）。次にホログラム記録媒体１の傾きが所定の範囲に入っているか判断を行う（８０５）。所定の範囲に入っていれば処理を終了し、入っていなければ、検出された傾きの量に応じてホログラム記録媒体の傾きをディスクチルト制御回路９１により調整する（８０６）。その後再度８０２～８０５の処理を繰り返し、ホログラム記録媒体１の傾きが
所定の範囲内に入るようにする。 FIG. 8 is a diagram showing an example of an operation flow for detecting the inclination of the hologram recording medium in the second embodiment. When the processing is started, first, the disk rotation motor control circuit is arranged so that the area to be detected for tilt of the hologram recording medium 1 is arranged in the vicinity of the position where the optical axis of the objective lens 215 and the optical axis of the lens 222 intersect. 88 and the access control circuit 81 (801). Next, the reference light is irradiated onto the hologram recording medium 1 at an angle that coincides with the optical axis of the lens 222 (802). Next, the reference light reflected by the hologram recording medium 1 is received by the photodetector 225 (803). Next, the inclination of the hologram recording medium 1 is calculated based on the received information (804). Next, it is determined whether the inclination of the hologram recording medium 1 is within a predetermined range (805). If it is within the predetermined range, the process is terminated, and if not, the tilt of the hologram recording medium is adjusted by the disc tilt control circuit 91 in accordance with the detected tilt amount (806). Thereafter, the processes of 802 to 805 are repeated again so that the inclination of the hologram recording medium 1 falls within a predetermined range.
　本実施例によれば、光情報記録再生装置１０において記録再生に必要な基本的な構成のみでホログラム記録媒体１の傾きを検出することが可能であり、一度装置から取り外した記録媒体を再度取り付けた場合に良好な品質で再生可能となる。また、所定回数の傾き検出を行う必要が無いため、第１の実施例と比べて短時間で処理を終えられる利点がある。 According to the present embodiment, the optical information recording / reproducing apparatus 10 can detect the inclination of the hologram recording medium 1 only with a basic configuration necessary for recording / reproducing, and the recording medium once removed from the apparatus is attached again. In this case, it can be reproduced with good quality. Further, since there is no need to perform a predetermined number of inclination detections, there is an advantage that the processing can be completed in a short time compared to the first embodiment.
　図９は第３の実施例におけるピックアップ１１の構成を示した図である。図９において、光源９０１を出射した光ビームはコリメートレンズ９０２を透過し、シャッタ９０３に入射する。シャッタ９０３が開いている時は、光ビームはシャッタ９０３を通過した後、例えば１／２波長板などで構成される光学素子９０４によってｐ偏光とｓ偏光の光量比が所望の比になるように偏光方向を制御された後、偏光ビームスプリッタ９０５に入射する。 FIG. 9 is a diagram showing the configuration of the pickup 11 in the third embodiment. In FIG. 9, the light beam emitted from the light source 901 passes through the collimator lens 902 and enters the shutter 903. When the shutter 903 is open, after the light beam passes through the shutter 903, the optical element 904 composed of, for example, a half-wave plate or the like adjusts the light quantity ratio of p-polarized light and s-polarized light to a desired ratio. After the polarization direction is controlled, the light enters the polarization beam splitter 905.
　偏光ビームスプリッタ９０５を透過した光ビームは、偏光ビームスプリッタ９０７を経由して空間光変調器９０８に入射する。空間光変調器９０８によって情報を付加された信号光９０６は偏光ビームスプリッタ９０７を反射し、所定の入射角度の光ビームのみを通過させるアングルフィルタ９０９を伝播する。その後、信号光ビームは対物レンズ９１０によってホログラム記録媒体１に集光する。 The light beam transmitted through the polarization beam splitter 905 enters the spatial light modulator 908 via the polarization beam splitter 907. The signal light 906 to which information is added by the spatial light modulator 908 is reflected by the polarization beam splitter 907 and propagates through an angle filter 909 that passes only a light beam having a predetermined incident angle. Thereafter, the signal light beam is focused on the hologram recording medium 1 by the objective lens 910.
　一方、偏光ビームスプリッタ９０５を反射した光ビームは参照光９１２として働き、偏光方向変換素子９１９によって記録時又は再生時に応じて所定の偏光方向に設定された後、ミラー９１３ならびにミラー９１４を経由してレンズ９１５に入射する。レンズ９１５は参照光９１２を対物レンズ９１０のバックフォーカス面に集光させる役割を果たしており、対物レンズ９１０のバックフォーカス面にて一度集光した参照光は、対物レンズ９１０によって再度、平行光となってホログラム記録媒体１に入射する。 On the other hand, the light beam reflected by the polarization beam splitter 905 acts as reference light 912, and is set to a predetermined polarization direction according to recording or reproduction by the polarization direction conversion element 919, and then passes through the mirror 913 and the mirror 914. The light enters the lens 915. The lens 915 plays a role of condensing the reference light 912 on the back focus surface of the objective lens 910, and the reference light once condensed on the back focus surface of the objective lens 910 is converted again into parallel light by the objective lens 910. Is incident on the hologram recording medium 1.
　ここで、対物レンズ９１０又は光学ブロック９２１は、例えば符号９２０に示す方向に駆動可能であり、対物レンズ９１０又は光学ブロック９２１の位置を駆動方向９２０に沿ってずらすことにより、対物レンズ９１０と対物レンズ９１０のバックフォーカス面における集光点の相対位置関係が変化するため、ホログラム記録媒体１に入射する参照光の入射角度を所望の角度に設定することができる。
なお、対物レンズ９１０又は光学ブロック９２１を駆動する代わりに、ミラー９１４をアクチュエータにより駆動することで参照光の入射角度を所望の角度に設定しても構わない。 Here, the objective lens 910 or the optical block 921 can be driven in the direction indicated by reference numeral 920, for example, and the objective lens 910 and the objective lens are shifted by shifting the position of the objective lens 910 or the optical block 921 along the driving direction 920. Since the relative positional relationship of the condensing points on the back focus surface 910 changes, the incident angle of the reference light incident on the hologram recording medium 1 can be set to a desired angle.
Instead of driving the objective lens 910 or the optical block 921, the incident angle of the reference light may be set to a desired angle by driving the mirror 914 with an actuator.
　このように、信号光と参照光をホログラム記録媒体１において、互いに重ね合うように入射させることで、記録媒体内には干渉縞パターンが形成され、このパターンを記録媒体に書き込むことで情報を記録する。また対物レンズ９１０又は光学ブロック９２１の位置を駆動方向９２０に沿ってずらすことによって、ホログラム記録媒体１に入射する参照光の入射角度を変化させることができるため、角度多重による記録が可能である。 In this way, by causing the signal light and the reference light to enter the hologram recording medium 1 so as to overlap each other, an interference fringe pattern is formed in the recording medium, and information is recorded by writing this pattern on the recording medium. . Further, by shifting the position of the objective lens 910 or the optical block 921 along the driving direction 920, the incident angle of the reference light incident on the hologram recording medium 1 can be changed, so that recording by angle multiplexing is possible.
　記録した情報を再生する場合は、前述したように参照光をホログラム記録媒体１に入射し、ホログラム記録媒体１を透過した光ビームをガルバノミラー９１６にて反射させることで、その再生用参照光を生成する。この再生用参照光によって再生された再生光は、対物レンズ９１０、アングルフィルタ９０９を伝播する。その後、再生光は偏光ビームスプリッタ９０７を透過して光検出器９１８に入射し、記録した信号を再生することができる。 When reproducing the recorded information, the reference light is incident on the hologram recording medium 1 as described above, and the light beam transmitted through the hologram recording medium 1 is reflected by the galvanometer mirror 916 so that the reproduction reference light is reflected. Generate. The reproduction light reproduced by the reproduction reference light propagates through the objective lens 910 and the angle filter 909. Thereafter, the reproduction light passes through the polarization beam splitter 907 and enters the photodetector 918, and the recorded signal can be reproduced.
　図９で示した光学系は、信号光と参照光を同一の対物レンズに入射させる構成とすることで、図２で示した光学系構成に比して、大幅に小型化できる利点を有する。 The optical system shown in FIG. 9 has an advantage that it can be significantly reduced in size as compared with the optical system configuration shown in FIG. 2 by making the signal light and the reference light incident on the same objective lens.
　図１０Ａ、図１０Ｂはピックアップ１１において、第３の実施例におけるホログラム記録媒体の傾きを検出するための原理を示した図である。図１０Ａはホログラム記録媒体１に傾きが無い基準の状態を示す。参照光のホログラム記録媒体１への入射角をθ０とする。ホログラム記録媒体１に傾きが無い場合は反射した参照光と対物レンズ９１０の光軸とがなす角はθ０となる。反射した参照光は対物レンズ９１０により集光しアングルフィルタ９０９と偏光ビームスプリッタ９０７を透過して光検出器９１８に入射する。集光した光が光検出器９１８に入射する位置と対物レンズ９１０の光軸との距離をｘ０とする。対物レンズ９１０の焦点距離をｆとして光軸からθだけ傾いた参照光が光検出器で光軸からｘだけずれて集光する場合に、一例としてｘ＝ｆ・ｓｉｎθの関係となっているものとすると、ｘ０＝ｆ・ｓｉｎθ０となる。 10A and 10B are diagrams showing the principle for detecting the tilt of the hologram recording medium in the third embodiment in the pickup 11. FIG. 10A shows a reference state in which the hologram recording medium 1 has no inclination. The incident angle of the reference light on the hologram recording medium 1 is θ 0 . When the hologram recording medium 1 is not inclined, the angle formed by the reflected reference light and the optical axis of the objective lens 910 is θ 0 . The reflected reference light is collected by the objective lens 910, passes through the angle filter 909 and the polarization beam splitter 907, and enters the photodetector 918. The distance between the optical axis position of the objective lens 910 focused light is incident on the light detector 918 and x 0. When reference light tilted by θ from the optical axis with the focal length of the objective lens 910 as f is condensed by a photodetector with a deviation of x from the optical axis, the relationship x = f · sin θ is given as an example. Then, x 0 = f · sin θ 0 .
　図１０Ｂはホログラム記録媒体１に傾きがある場合の状態を示す。図１０Ｂではホログラム記録媒体の角度が図１０Ａの基準状態からΔθだけずれているものとする。このとき、角度θ０の参照光はホログラム記録媒体１で反射した際にθ０＋２Δθだけ対物レンズの光軸から傾くため、反射した参照光が光検出器９１８に集光する位置の基準状態からのずれをΔｘとすると、ｘ＋Δｘ＝ｆ・ｓｉｎ（θ０＋２Δθ）の関係となる。これより、Δθ＝｛ｓｉｎ-１（（ｘ０＋Δｘ）／ｆ）－θ０｝／２であるため、ホログラム記録媒体１の基準状態からの角度ずれ量を算出することができる。 FIG. 10B shows a state where the hologram recording medium 1 is tilted. In FIG. 10B, it is assumed that the angle of the hologram recording medium is shifted by Δθ from the reference state of FIG. 10A. At this time, the reference light having the angle θ 0 is tilted from the optical axis of the objective lens by θ 0 + 2Δθ when reflected by the hologram recording medium 1. Assuming that the deviation is Δx, the relationship is x + Δx = f · sin (θ 0 + 2Δθ). Accordingly, since Δθ = {sin −1 ((x 0 + Δx) / f) −θ 0 } / 2, the amount of angular deviation from the reference state of the hologram recording medium 1 can be calculated.
　第３の実施例におけるホログラム記録媒体の傾き検出を行うための動作フローとしては第１の実施例や第２の実施例で用いた動作フローを適用することができる。 As the operation flow for detecting the tilt of the hologram recording medium in the third embodiment, the operation flow used in the first embodiment or the second embodiment can be applied.
　第４の実施例における装置構成は第１の実施例と同様である。 The apparatus configuration in the fourth embodiment is the same as that in the first embodiment.
　図１１は第４の実施例において参照光の基準となる角度をオフセットさせるための動作フローの一例を示した図である。処理が開始されると、まずホログラム記録媒体１の傾き検出の対象となる領域が対物レンズ２１５の光軸とレンズ２２２の光軸の交差する位置の近傍に配置されるようにディスク回転モータ制御回路８８とアクセス制御回路８１を用いて制御する（１１０１）。次に参照光がレンズ２２２の光軸と一致する角度でホログラム記録媒体１に照射する（１１０２）。次にホログラム記録媒体１で反射した参照光を光検出器２２５で受光する（１１０３）。次に受光した情報を基に、ホログラム記録媒体１の傾きを算出する（１１０４）。１１０２では参照光がレンズ２２２の光軸と一致する角度を基準としていたが、算出したホログラム記録媒体１の傾きの情報を基に、基準となる角度をオフセットさせて終了する（１１０５）。 FIG. 11 is a diagram showing an example of an operation flow for offsetting an angle that is a reference light reference in the fourth embodiment. When the processing is started, first, the disk rotation motor control circuit is arranged so that the area to be detected for tilt of the hologram recording medium 1 is arranged in the vicinity of the position where the optical axis of the objective lens 215 and the optical axis of the lens 222 intersect. 88 and the access control circuit 81 (1101). Next, the reference light is irradiated onto the hologram recording medium 1 at an angle that coincides with the optical axis of the lens 222 (1102). Next, the reference light reflected by the hologram recording medium 1 is received by the photodetector 225 (1103). Next, the inclination of the hologram recording medium 1 is calculated based on the received information (1104). In 1102, the angle at which the reference light coincides with the optical axis of the lens 222 is used as a reference. However, the reference angle is offset based on the calculated information on the tilt of the hologram recording medium 1, and the process ends (1105).
　図１２は図１Ａ、図１Ｂと同様の構成において、ホログラム記録媒体の傾きの情報を基に基準となる角度をオフセットさせる量を示した図である。光情報記録媒体に傾きΔθがある場合には、図１Ｂで示したように参照光が光検出器で光軸からΔｘ＝ｆ・ｓｉｎ２Δθだけずれて検出される。このとき、１１０４でΔθ＝｛ｓｉｎ-１（Δｘ／ｆ）｝／２としてホログラム記録媒体の傾きを算出することができる。１１０５で参照光の基準となる角度を図１２に示すようにΔθオフセットさせることで、ホログラム記録媒体と参照光の基準となる角度との関係を適正に保つことができる。 FIG. 12 is a diagram showing an amount of offsetting the reference angle based on the information on the inclination of the hologram recording medium in the same configuration as in FIGS. 1A and 1B. When the optical information recording medium has an inclination Δθ, the reference light is detected by being shifted by Δx = f · sin 2 Δθ from the optical axis by the photodetector as shown in FIG. 1B. At this time, in 1104, the inclination of the hologram recording medium can be calculated as Δθ = {sin −1 (Δx / f)} / 2. By offsetting the angle that becomes the reference light reference in 1105 by Δθ as shown in FIG. 12, the relationship between the hologram recording medium and the angle that becomes the reference light reference can be properly maintained.
　なお、このようにして基準となる角度をオフセットさせた場合、ホログラム記録媒体で反射した参照光は対物レンズ２１５の光軸からΔθだけずれているため、光検出器２２５上で参照光はΔｘ１＝ｆ・ｓｉｎΔθだけずれて検出される。１１０５の後にΔｘ１を検出し、意図した通りに参照光がオフセットしているかを確認しても構わない。 When the reference angle is offset in this way, the reference light reflected by the hologram recording medium is shifted by Δθ from the optical axis of the objective lens 215, so that the reference light on the photodetector 225 is Δx 1 = It is detected with a deviation of f · sin Δθ. Δx1 may be detected after 1105 to check whether the reference light is offset as intended.
　本実施例によれば、一度装置から取り外した記録媒体を再度取り付けた場合に良好な品質で再生可能となるだけでなく、ホログラム記録媒体の角度を制御する機構が不要となるため、低コストで光情報記録再生装置１０を構成することができる。 According to this embodiment, when a recording medium once removed from the apparatus is reattached, not only can it be reproduced with good quality, but also a mechanism for controlling the angle of the hologram recording medium is not required, so that the cost can be reduced. The optical information recording / reproducing apparatus 10 can be configured.
　以上の説明では検出したホログラム記録媒体１の傾きの情報を用いてホログラム記録媒体１の傾きを補正するものとして説明を行ったが、必ずしもホログラム記録媒体１の傾き補正のために利用しなくても良く、例えば検出されたホログラム記録媒体の傾きの情報を基に光検出器における再生像の位置検出に利用しても構わない。 In the above description, the description has been made on the assumption that the tilt information of the hologram recording medium 1 is corrected using the detected information of the tilt of the hologram recording medium 1. However, the information is not necessarily used for correcting the tilt of the hologram recording medium 1. For example, it may be used for detecting the position of the reproduced image in the photodetector based on the detected tilt information of the hologram recording medium.
　なお、以上の説明では参照光の多重方向と同じ方向の角度のホログラム記録媒体の傾きについて説明を行ったが、これと垂直な方向のホログラム記録媒体の傾きについても同様の原理を用いて検出可能である。 In the above description, the inclination of the hologram recording medium having the same angle as the reference light multiplexing direction has been described, but the inclination of the hologram recording medium in the direction perpendicular thereto can also be detected using the same principle. It is.
　また、以上の説明では記録や再生に先立って行う学習処理における動作として説明を行ったが、記録中や再生中に同様のホログラム記録媒体の傾き検出を行い、適宜、ホログラム記録媒体の角度を制御しても構わない。記録中の場合には、通常光検出器は利用していないため、参照光の偏光状態を制御することで、ホログラム記録媒体１で反射した参照光の一部を光検出器で検出することができる。再生中の場合には、再生されたデータとホログラム記録媒体１で反射した参照光が同時に光検出器で検出されるが、反射した参照光は高い輝度で検出されるため、例えば閾値を設けて、光検出器において検出された光強度が閾値以上の画素の情報を参照光の情報と考えて傾き検出を行えば良い。
　上記記載は実施例についてなされたが、本発明はそれに限らず、本発明の精神と添付の請求の範囲の範囲内で種々の変更および修正をすることができることは当業者に明らかである。 In the above explanation, the operation in the learning process prior to recording and reproduction was explained. However, the inclination of the same hologram recording medium is detected during recording and reproduction, and the angle of the hologram recording medium is controlled appropriately. It doesn't matter. In the case of recording, since a normal photodetector is not used, a part of the reference light reflected by the hologram recording medium 1 can be detected by the photodetector by controlling the polarization state of the reference light. it can. In the case of reproduction, the reproduced data and the reference light reflected by the hologram recording medium 1 are simultaneously detected by the photodetector. However, since the reflected reference light is detected with high luminance, for example, a threshold is provided. The inclination detection may be performed by regarding the information of the pixels whose light intensity detected by the photodetector is equal to or greater than the threshold value as the information of the reference light.
While the above description has been made with reference to exemplary embodiments, it will be apparent to those skilled in the art that the invention is not limited thereto and that various changes and modifications can be made within the spirit of the invention and the scope of the appended claims.
　１　ホログラム記録媒体
　１０　光情報記録再生装置
　１１　ピックアップ
　１２　再生用参照光光学系
　１３　ディスクＣｕｒｅ光学系
　１４　ディスク回転角度検出用光学系
　５０　回転モータ
　８１　アクセス制御回路
　８２　光源駆動回路
　８３　サーボ信号生成回路
　８４　サーボ制御回路
　８５　信号処理回路
　８６　信号生成回路
　８７　シャッタ制御回路
　８８　ディスク回転モータ制御回路
　８９　コントローラ
　２０１　光源
　２０２　コリメートレンズ
　２０３　シャッタ
　２０４　１／２波長板
　２０５　偏光ビームスプリッタ
　２０６　信号光
　２０７　参照光
　２０８　ビームエキスパンダ
　２０９　フェーズ（位相）マスク
　２１０　リレーレンズ
　２１１　偏光ビームスプリッタ
　２１２　空間光変調器
　２１３　リレーレンズ
　２１４　空間フィルタ
　２１５　対物レンズ
　２１６　偏光方向変換素子
　２１７　ミラー
　２１８　ミラー
　２１９　ミラー
　２２０　アクチュエータ
　２２１　レンズ
　２２２　レンズ
　２２３　アクチュエータ
　２２４　ミラー
　２２５　光検出器
　９０１　光源
　９０２　コリメートレンズ
　９０３　シャッタ
　９０４　偏光方向変換素子
　９０５　偏光ビームスプリッタ
　９０６　信号光
　９０７　偏光ビームスプリッタ
　９０８　空間光変調器
　９０９　アングルフィルタ
　９１０　対物レンズ
　９１１　アクチュエータ
　９１２　参照光
　９１３　ミラー
　９１４　ミラー
　９１５　レンズ
　９１６　ミラー
　９１７　アクチュエータ
　９１８　光検出器
　９１９　偏光方向変換素子
　９２０　駆動方向
　９２１　光学ブロック
  DESCRIPTION OF SYMBOLS 1 Hologram recording medium 10 Optical information recording / reproducing apparatus 11 Pickup 12 Reference light optical system for reproduction | regeneration 13 Disc Cure optical system 14 Optical system for disc rotation angle detection 50 Rotation motor 81 Access control circuit 82 Light source drive circuit 83 Servo signal generation circuit 84 Servo Control circuit 85 Signal processing circuit 86 Signal generation circuit 87 Shutter control circuit 88 Disc rotation motor control circuit 89 Controller 201 Light source 202 Collimate lens 203 Shutter 204 1/2 wavelength plate 205 Polarizing beam splitter 206 Signal light 207 Reference light 208 Beam expander 209 Phase mask 210 Relay lens 211 Polarizing beam splitter 212 Spatial light modulator 213 Relay lens 214 Spatial filter 215 Objective lens 216 Polarization direction conversion Child 217 Mirror 218 Mirror 219 Mirror 220 Actuator 221 Lens 222 Lens 223 Actuator 224 Mirror 225 Photodetector 901 Light source 902 Collimator lens 903 Shutter 904 Polarization direction conversion element 905 Polarization beam splitter 906 Signal light 907 Polarization beam splitter 908 Spatial light modulator 909 Angle filter 910 Objective lens 911 Actuator 912 Reference beam 913 Mirror 914 Mirror 915 Lens 916 Mirror 917 Actuator 918 Photo detector 919 Polarization direction conversion element 920 Drive direction 921 Optical block

Claims (8)

  1. 　信号光と参照光との干渉パターンがページデータとして記録されているホログラム記録媒体から情報を再生するホログラフィックメモリ再生装置であって、
    　レーザ光を出射するレーザ光源と、
    　前記レーザ光を参照光と信号光に分離する光学素子と、
    　前記参照光により再生されたページデータと前記ホログラム記録媒体で反射した参照光の強度分布とを検出する光検出器と、を備え、
    　前記光検出器により前記反射した参照光の前記光検出器上の位置を検出し、検出した位置情報を基に前記ホログラム記録媒体の傾きを検出することを特徴とするホログラフィックメモリ再生装置。     A holographic memory reproducing device for reproducing information from a hologram recording medium in which an interference pattern between signal light and reference light is recorded as page data,
    A laser light source for emitting laser light;
    An optical element for separating the laser light into reference light and signal light;
    A photodetector for detecting the page data reproduced by the reference light and the intensity distribution of the reference light reflected by the hologram recording medium;
    A holographic memory reproducing apparatus, wherein a position of the reflected reference light on the photodetector is detected by the photodetector, and an inclination of the hologram recording medium is detected based on the detected position information.
  2. 　前記反射した参照光はホログラム記録媒体の表面で反射することを特徴とする請求項１に記載のホログラフィックメモリ再生装置。 2. The holographic memory reproducing device according to claim 1, wherein the reflected reference light is reflected by a surface of a hologram recording medium.
  3. 　前記反射した参照光はホログラム記録媒体の記録材料の厚み方向における中央近傍で反射することを特徴とする請求項１に記載のホログラフィックメモリ再生装置。 The holographic memory reproducing device according to claim 1, wherein the reflected reference light is reflected near the center in the thickness direction of the recording material of the hologram recording medium.
  4. 　請求項１記載のホログラフィックメモリ再生装置であって、
    　ホログラム記録媒体の傾きを補正するアクチュエータを備え、
    　前記検出したホログラム記録媒体の傾きの情報を基に前記ホログラム記録媒体の傾きを前記アクチュエータにより補正することを特徴とする請求項１に記載のホログラフィックメモリ再生装置。     The holographic memory reproducing device according to claim 1,
    An actuator for correcting the tilt of the hologram recording medium,
    2. The holographic memory reproducing device according to claim 1, wherein the actuator corrects the inclination of the hologram recording medium based on the detected information of the inclination of the hologram recording medium.
  5. 　請求項１記載のホログラフィックメモリ再生装置であって、 
    　参照光角度を調整するミラーを備え、
    　前記検出したホログラム記録媒体の傾きの情報を基に前記ホログラム記録媒体の傾きを前記ミラーにより補正することを特徴とする請求項１に記載のホログラフィックメモリ再生装置。     The holographic memory reproducing device according to claim 1,
    It has a mirror to adjust the reference beam angle,
    The holographic memory reproducing apparatus according to claim 1, wherein the tilt of the hologram recording medium is corrected by the mirror based on the detected tilt information of the hologram recording medium.
  6. 　信号光と参照光とを用いたホログラフィを利用して、ホログラム記録媒体から情報を再生するホログラフィックメモリ再生方法において、
    　前記ホログラム記録媒体に参照光を照射する工程と、
    　前記ホログラム記録媒体において反射した参照光の強度分布を検出する工程と、
    　前記検出した強度分布に基づいて前記ホログラム記録媒体の傾きを検出する工程と、を含むことを特徴とするホログラフィックメモリ再生方法。     In a holographic memory reproducing method for reproducing information from a hologram recording medium using holography using signal light and reference light,
    Irradiating the hologram recording medium with reference light; and
    Detecting an intensity distribution of reference light reflected on the hologram recording medium;
    Detecting the tilt of the hologram recording medium based on the detected intensity distribution.
  7. 　信号光と参照光との干渉パターンをページデータとして記録するホログラム記録媒体であって、
    　表面の少なくとも一部に参照光を反射させるための領域を設けていることを特徴とするホログラム記録媒体。     A hologram recording medium for recording an interference pattern of signal light and reference light as page data,
    A hologram recording medium comprising a region for reflecting reference light on at least a part of a surface.
  8. 　信号光と参照光との干渉パターンをページデータとして記録するホログラム記録媒体であって、
    　記録材料の厚み方向の中央近傍の少なくとも一部に参照光を反射させるための領域を設けていることを特徴とするホログラム記録媒体。
          A hologram recording medium for recording an interference pattern of signal light and reference light as page data,
    A hologram recording medium, characterized in that an area for reflecting reference light is provided at least in the vicinity of the center of the recording material in the thickness direction.
PCT/JP2012/061039 2011-09-16 2012-04-25 Holographic memory playback device, holographic memory playback method, and hologram recording medium WO2013038745A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2011202550A JP5802494B2 (en) 2011-09-16 2011-09-16 Holographic memory reproducing device, holographic memory reproducing method and hologram recording medium
JP2011-202550 2011-09-16

Publications (1)

Publication Number Publication Date
WO2013038745A1 true WO2013038745A1 (en) 2013-03-21

Family

ID=47882991

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2012/061039 WO2013038745A1 (en) 2011-09-16 2012-04-25 Holographic memory playback device, holographic memory playback method, and hologram recording medium

Country Status (2)

Country Link
JP (1) JP5802494B2 (en)
WO (1) WO2013038745A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004110931A (en) * 2002-09-18 2004-04-08 Ricoh Co Ltd Optical pickup and optical information recording and reproducing device
JP2008287077A (en) * 2007-05-18 2008-11-27 Canon Inc Optical information recording and reproducing apparatus
JP2010250908A (en) * 2009-04-17 2010-11-04 Sony Corp Hologram device, tilt detection method, and tilt correction method

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5125351B2 (en) * 2007-09-25 2013-01-23 株式会社日立製作所 Optical information recording / reproducing apparatus
JP5187925B2 (en) * 2008-05-28 2013-04-24 石福金属興業株式会社 Conductive material
JP4969558B2 (en) * 2008-11-26 2012-07-04 株式会社日立製作所 Optical information reproducing apparatus, optical information recording / reproducing apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004110931A (en) * 2002-09-18 2004-04-08 Ricoh Co Ltd Optical pickup and optical information recording and reproducing device
JP2008287077A (en) * 2007-05-18 2008-11-27 Canon Inc Optical information recording and reproducing apparatus
JP2010250908A (en) * 2009-04-17 2010-11-04 Sony Corp Hologram device, tilt detection method, and tilt correction method

Also Published As

Publication number Publication date
JP2013064810A (en) 2013-04-11
JP5802494B2 (en) 2015-10-28

Similar Documents

Publication Publication Date Title
JP5358530B2 (en) Optical information recording / reproducing apparatus and reproducing apparatus
JP5037391B2 (en) Optical pickup, optical information recording / reproducing apparatus, and optical information recording / reproducing method
JP5096191B2 (en) Optical pickup, optical information reproducing apparatus and optical information recording / reproducing apparatus using the same
JP5183667B2 (en) Playback apparatus and playback method
JP4881914B2 (en) Optical information recording / reproducing apparatus and optical information recording method
JP5125351B2 (en) Optical information recording / reproducing apparatus
JP4969558B2 (en) Optical information reproducing apparatus, optical information recording / reproducing apparatus
JP6134738B2 (en) Optical information recording / reproducing apparatus and optical information recording / reproducing method
US7903526B2 (en) Recording/reproducing apparatus, method of reproducing data, and servo controlling method
JP5320343B2 (en) Optical information recording / reproducing apparatus and optical information recording / reproducing method
JP5104695B2 (en) Information recording device
JP2014026706A (en) Holographic memory apparatus and method for adjusting incident angle of reference beam
JP2013109794A (en) Optical information recording/reproducing apparatus, optical information recording/reproducing method, and optical information recording medium
JP5557787B2 (en) Optical information reproducing apparatus, optical information recording / reproducing apparatus
JP2009087447A (en) Apparatus and method for recording/reproducing optical information, and optical information recording medium
JP5211816B2 (en) Optical information recording / reproducing apparatus
JP5075556B2 (en) Optical information recording / reproducing apparatus and disc discrimination method
JP5802494B2 (en) Holographic memory reproducing device, holographic memory reproducing method and hologram recording medium
WO2014091531A1 (en) Optical information reproduction device and optical information reproduction method
JP2012069207A (en) Holographic memory using holography
JP4861951B2 (en) Optical information recording / reproducing device
WO2014097412A1 (en) Optical information reproduction apparatus and optical information reproduction method
JP5542739B2 (en) Holographic memory reproducing apparatus and holographic memory reproducing method
JP5647965B2 (en) Optical information recording / reproducing apparatus, optical information recording apparatus, optical information recording / reproducing method, and optical information recording medium
JP2012138148A (en) Apparatus and method for recording and reproducing information

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12831439

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12831439

Country of ref document: EP

Kind code of ref document: A1