WO2017042900A1 - Dispositif d'enregistrement d'informations optiques, dispositif d'enregistrement/reproduction d'informations optiques, et procédé d'enregistrement d'informations optiques - Google Patents

Dispositif d'enregistrement d'informations optiques, dispositif d'enregistrement/reproduction d'informations optiques, et procédé d'enregistrement d'informations optiques Download PDF

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WO2017042900A1
WO2017042900A1 PCT/JP2015/075527 JP2015075527W WO2017042900A1 WO 2017042900 A1 WO2017042900 A1 WO 2017042900A1 JP 2015075527 W JP2015075527 W JP 2015075527W WO 2017042900 A1 WO2017042900 A1 WO 2017042900A1
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Prior art keywords
light
optical information
information recording
phase
signal
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PCT/JP2015/075527
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English (en)
Japanese (ja)
Inventor
啓太 山口
充 永沢
誠 保坂
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株式会社日立製作所
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Priority to PCT/JP2015/075527 priority Critical patent/WO2017042900A1/fr
Publication of WO2017042900A1 publication Critical patent/WO2017042900A1/fr

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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
    • G11B7/0045—Recording
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
    • G11B7/0065—Recording, reproducing or erasing by using optical interference patterns, e.g. holograms
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector

Definitions

  • the present invention relates to an optical information recording apparatus, an optical information recording / reproducing apparatus, and an optical information recording method using holography.
  • Patent Document 1 JP 2008-203503
  • the first reference light is applied to the hologram recording medium 30”.
  • the first reference beam path that guides the laser beam from the laser 11 to irradiate the laser beam, and the diffracted beam that guides the diffracted beam generated from the hologram recording medium 30 by the irradiation of the first reference beam to the CMOS sensor 27 having a plurality of pixels.
  • the delay element 16 and the biaxial rotating mirror 18 are arranged so that the phase of the diffracted light and the second reference light are matched to obtain a favorable DC reproduction characteristic.
  • hologram recording / reproducing technology that records and reproduces information two-dimensionally modulated using holography is attracting attention.
  • two-dimensional information is added to the signal light, and interference fringes formed by superimposing with the reference light are recorded in the recording medium.
  • the diffracted light reproduced by irradiating the interference fringes of the recording medium with reference light is detected by the image sensor, and two-dimensional information is reproduced.
  • phase multilevel technology for adding multilevel phase information to light has been proposed as a technology for adding two-dimensional information to light.
  • light having high coherence oscillator light
  • the phase of the oscillator light is controlled by a phase modulation element, and the phase difference between the diffracted light and the oscillator light can be matched.
  • Patent Document 1 since the technique of Patent Document 1 does not consider the phase difference change between the signal light and the reference light at the time of recording, there is a problem that the deterioration of the reproduction performance due to the phase difference change at the time of recording cannot be sufficiently suppressed. .
  • the present invention provides an optical information recording technique capable of stably reproducing phase multilevel information by correcting a phase difference change between signal light and reference light during recording and recording a high-quality hologram.
  • the purpose is to do.
  • an optical information recording apparatus that causes reference light and signal light to interfere with each other and records the obtained interference fringes as a hologram on a hologram recording medium
  • a light source that emits light, light emitted from the light source, first light and second light
  • a light beam splitting element that splits the first light and the second light to detect interference intensity, and the first light based on the interference intensity detected by the light receiving section.
  • a phase controller that calculates a phase difference of the second light and controls at least a phase of the second light; and a spatial light modulator that adds phase multilevel information to the second light.
  • an optical information recording / reproducing apparatus and recording that can reproduce stable phase multilevel information by correcting a phase difference change between signal light and reference light during recording and recording a high-quality hologram.
  • a playback method can be provided.
  • the figure showing the optical pick-up apparatus in the optical information recording and reproducing apparatus in Example 1 The figure showing the optical information recording and reproducing apparatus in Example 1 Signal point arrangement diagram showing phase four-value recording method in embodiment 1
  • the figure showing the optical pick-up apparatus in the optical information recording and reproducing apparatus in Example 1 Signal point arrangement diagram showing phase four-value reproduction method in embodiment 1 Histogram of interference intensity at the time of quaternary phase reproduction in embodiment 1
  • the figure showing the relationship between the light which injects into the photodetector in Example 1, and a light-receiving part Relationship between interference intensity and phase difference between first detection light and second detection light in Embodiment 1 1 is a configuration diagram of a circuit that performs phase difference control between signal light and reference light during recording in Embodiment 1.
  • FIG. Example 4 recording flow of phase 4 values by two recordings Page / book recording flow in the first embodiment
  • Configuration diagram of polarization direction conversion element in Example 4 The figure showing the production
  • FIG. 2 is a block diagram showing a recording / reproducing apparatus for an optical information recording medium for recording and / or reproducing digital information using holography.
  • the optical information recording / reproducing device 10 is connected to an external control device 91 via an input / output control circuit 90.
  • the optical information recording / reproducing apparatus 10 receives the information signal to be recorded from the external control device 91 by the input / output control circuit 90.
  • the optical information recording / reproducing apparatus 10 transmits the reproduced information signal to the external control apparatus 91 by the input / output control circuit 90.
  • the optical information recording / reproducing apparatus 10 includes a pickup 11, a cure optical system 13, a disk rotation angle detection optical system 14, and a rotation motor 50, and the optical information recording medium 1 can be rotated by the rotation motor 50. ing.
  • the pickup 11 plays a role of irradiating the optical information recording medium 1 with reference light and signal light to record digital information on the recording medium using holography and reproducing information recorded on the optical information recording medium 1.
  • the information signal to be recorded is sent to the spatial light modulator in the pickup 11 by the controller 89 via the signal generation circuit 86, and the signal light is modulated by the spatial light modulator.
  • controller 89 drives the phase modulation element in the pickup 11 via the phase control circuit 92 to control the phase of the signal light and the reference light.
  • the pickup 11 When reproducing the information recorded on the optical information recording medium 1, the pickup 11 causes the reference light to enter the optical information recording medium in the opposite direction to that during recording. Reproduced light reproduced by the reference light is detected by a later-described photodetector 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 optical information recording medium 1 can be adjusted by controlling the opening / closing time of the shutter in the pickup 11 via the shutter control circuit 87 by the controller 89.
  • the cure optical system 13 plays a role of generating a light beam used for pre-cure and post-cure of the optical information recording medium 1.
  • Precure is a pre-process for irradiating a predetermined light beam in advance before irradiating the desired position with reference light and signal light when recording information at a desired position in the optical information recording medium 1.
  • Post-cure is a post-process for irradiating a predetermined light beam after recording information at a desired position in the optical information 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 optical information recording medium 1.
  • a signal corresponding to the rotation angle is detected by the disk rotation angle detection optical system 14, and a disk rotation motor control circuit is detected by the controller 89 using the detected signal.
  • the rotation angle of the optical information recording medium 1 can be controlled via 88.
  • 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 optical information recording medium 1, and the position is controlled via the access control circuit 81.
  • the recording technology 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. 1 shows a recording principle in an example of a basic optical system configuration of the optical pickup device 11 in the optical information recording / reproducing apparatus of the present embodiment.
  • the light beam emitted from the light source 301 passes through the collimator lens 302 and enters the shutter 303.
  • the shutter 303 is open, after the light beam passes through the shutter 303, the optical ratio of the p-polarized light and the s-polarized light becomes a desired ratio by the optical element 304 composed of, for example, a half-wave plate.
  • the polarization direction is controlled, the light enters the polarization beam splitter 305.
  • the light beam that has passed through the polarization beam splitter 305 functions as signal light 306, and after the light beam diameter is expanded by the beam expander 308, the non-polarization beam splitter 326, the phase modulation element 309, the non-polarization beam splitter 332, the polarization direction It passes through the conversion element 310 and the polarization beam splitter 311 and enters the spatial light modulator 312, and becomes two-dimensional data (hereinafter, page data) to which phase information is added for each pixel by the spatial light modulator 312.
  • the phase distribution in the page data is, for example, a phase distribution that removes DC intensity (so-called hot spot) in the light intensity distribution on the Fourier plane of the optical information recording medium 1.
  • the signal light 306 to which page data is added by the spatial light modulator 312 is reflected by the polarization beam splitter 311 and propagates through the relay lens 313 and the spatial filter 314. Thereafter, the light is condensed on the optical information recording medium 1 by the objective lens 315.
  • the light beam reflected from the polarization beam splitter 305 functions as reference light 307, and is set to a predetermined polarization direction according to recording or reproduction by the polarization direction conversion element 316, and then passes through the mirror 317 to the galvanometer mirror 319.
  • the angle of the galvanometer mirror 319 can be adjusted by the actuator 320, the incident angle of the reference light incident on the optical information recording medium 1 after passing through the lens 321 and the lens 322 can be set to a desired angle.
  • an element that converts the wavefront of the reference light may be used instead of the galvanometer mirror.
  • the signal 306 and the reference light 307 are incident on the optical information recording medium 1 so as to overlap each other, whereby an interference fringe pattern is formed in the recording medium, and information is written by writing this pattern on the recording medium. Record.
  • 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. 3 shows a complex plane.
  • the absolute value of a point on the complex plane represents the amplitude of the signal light 306, and the declination represents the phase difference between the signal light 306 and the reference light 307.
  • the phase of the signal light is a value based on the phase of the reference light.
  • FIG. 3A is a signal point arrangement diagram showing an example of binary information added by the spatial light modulator 312 by points on a complex plane.
  • the spatial light modulator 312 adds binary information of a phase 0 signal point 401 and a phase ⁇ signal point 402.
  • the phase modulation element 309 changes the phase of the signal light 306 by ⁇ / 2.
  • the binary information of the signal point 403 of phase ⁇ / 2 and the signal point 404 of phase 3 ⁇ / 2 shown in 3 (b) is recorded in the same location of the optical information recording medium 1.
  • the signal point 405 of phase ⁇ / 4 the signal point 406 of phase 3 ⁇ / 4, and the phase of 5 ⁇ / 4 shown in the signal point arrangement diagram of FIG.
  • a signal point 407 and a signal point 408 having a phase of 7 ⁇ / 4 are recorded.
  • FIG. 4 shows a reproduction principle in an example of a basic optical system configuration of the optical pickup device 11 in the optical information recording / reproducing apparatus of the present embodiment.
  • the reference light 307 enters the optical information recording medium 1.
  • a reproduction method using phase conjugate light is used, and the reference light 307 transmitted through the optical information recording medium 1 is reflected from the galvano mirror 324 whose angle can be adjusted by the actuator 323, and again, the optical information recording medium 1
  • the information is reproduced using the reference light 307 incident on the.
  • the diffracted light 337 reproduced by the reference light 307 enters the photodetector 325 through the objective lens 315, the relay lens 313, the spatial filter 314, the polarization beam splitter 311, and the polarizer 339.
  • interference between the diffracted light 337 and light having high coherence is used.
  • the polarization direction is controlled by the polarization direction conversion element 304, and a desired amount of light is transmitted through the polarization beam splitter 305.
  • the oscillator light 338 transmitted through the polarization beam splitter 305 passes through the beam expander 308, the non-polarization beam splitter 326, the phase modulation element 309, and the non-polarization beam splitter 332, and then the polarization direction is controlled by the polarization direction conversion element 310. Reflects the polarization beam splitter 311. Thereafter, the oscillator light 338 enters the photodetector 325 through the polarizer 339.
  • FIG. 5 is a diagram for explaining a method for reproducing phase information from interference between the diffracted light 337 and the oscillator light, which is a method for reproducing the signal point of the phase multilevel information of the diffracted light 337 in this embodiment.
  • the interference phase [Phi LO oscillator light 338 and the phase of the reference light as a reference, the signal point 405, the signal points 406, signal point 407, the signal points 408, declination It can be regarded as a projection onto an axis 409 having ⁇ LO .
  • the intensity difference between the signal point 405 and the signal point 408 is proportional to the distance 410
  • the intensity difference between the signal point 408 and the signal point 406 is proportional to the distance 411
  • the intensity difference between 406 and signal point 407 is proportional to distance 412.
  • FIG. 6 is a histogram obtained when the signal of FIG. 5 is reproduced.
  • the horizontal axis indicates the light intensity detected by the photodetector 325
  • the vertical axis indicates the number of pixels having each interference intensity in the page data.
  • a histogram is shown in a state where four signal points (405, 406, 407, 408) are arranged in the same number of page data.
  • four signal points (405, 406, 407, 408) are arranged at equal intervals, and the interference intensity corresponding to each signal point can be separated. Reproduction performance is obtained.
  • the present embodiment is not limited to the method of separating the signal point 405, the signal point 406, the signal point 407, and the signal point 408 all at once, but four phases (arbitrary reference phase, reference phase + ⁇ / 2, reference phase). + ⁇ , reference phase + 3 ⁇ / 2) is added to the oscillator light 338 to detect the phase from the principle of fringe scanning generally used in interferometers, etc. The same effect can be obtained by using.
  • the photodetector 325 can be an image sensor such as a CMOS image sensor or a CCD image sensor, for example, but may be any element as long as page data can be reproduced.
  • FIG. 7 (b) shows a state in which these signal points, to play on interference with the oscillator beam having a phase [Phi LO. Projection of the signal point 501, the signal point 502, the signal point 503, and the signal point 504 onto the axis 409 having the declination ⁇ LO is as shown in FIG. 7B, and the distance 507 between the signal point 502 and the signal point 504 is shown in FIG. 6 is smaller than the distance 411 of 6.
  • FIG. 8 shows an interference intensity histogram of the oscillator light added with the diffracted light 337 and the phase ⁇ LO at this time. The difference in interference intensity between the signal point 502 and the signal point 504 decreases, and the reproduction performance of the phase information deteriorates.
  • the amplitudes of the signal point 501 and the signal point 503 are increased, but the amplitudes of the signal point 502 and the signal point 504 are decreased.
  • the amount of light in the portion where the point 504 is added decreases. For this reason, the reproduction performance equivalent to the case of FIGS. 5 and 6 cannot be obtained only by optimizing the phase ⁇ LO of the oscillator light.
  • a part of the signal light 306 is reflected by the non-polarizing beam splitter 326.
  • the reflected light beam is referred to as first detection light 328.
  • the first detection light 328 is reflected by the non-polarizing beam splitter 330 via the mirror 329 and then enters the photodetector 331.
  • a part of the signal light 306 transmitted through the non-polarizing beam splitter 326 reflects the non-polarizing beam splitter 332.
  • the reflected light beam is referred to as second detection light 334.
  • the second detection light 334 passes through the non-polarizing beam splitter 330 and then enters the photodetector 331.
  • FIG. 9 shows the relationship between the light receiving unit 801 of the photodetector 331 and the first detection light 328 and the second detection light 334 incident on the photodetector 331.
  • the light receiving unit 301 detects the interference intensity between the first detection light 328 and the second detection light 334.
  • the photodetector 331 may be an image sensor such as a CMOS image sensor or a CCD image sensor, or may be an element that detects light intensity, such as a photodetector.
  • Equation 1 is an expression representing the interference intensity I between the first detection light 328 and the second detection light 334.
  • E 1 represents the complex amplitude of the first detection light 328
  • E 2 represents the complex amplitude of the second detection light 334
  • ⁇ represents the difference between the initial phase of the first detection light 328 and the initial phase of the second detection light 334.
  • Interference the intensity I is next to the square of the absolute value of the sum of the complex amplitude E 2 of the complex amplitude E 1 and the second detection light 334 of the first detection light 328, the intensity of the first detection light 328
  • FIG. 10 shows the relationship between the interference intensity I and the phase difference ⁇ when
  • the phase modulation element 309 When the phase modulation element 309 is driven before the first recording and the interference intensity detected by the photodetector 331 is maximized, the first detection light 328 and the second detection light 334 are changed as indicated by a point 901 in FIG. The phase difference becomes zero. After the first recording is completed, the phase modulation element 309 is driven so that the interference intensity detected by the photodetector 331 becomes half of the maximum value, and moves to a point 902 in FIG. By performing the second recording in this state, the second recording can be performed in a state where the phase difference between the first detection light 328 and the second detection light 334 is ⁇ / 2.
  • an interference fringe pattern is formed on the optical information recording medium 1 by driving the phase modulation element 309 to move the point 901 in the first recording and the point 902 in the second recording.
  • the phase of the signal light 306 can be changed by ⁇ / 2 between the first recording and the second recording.
  • FIG. 11 shows a configuration of a phase control circuit 92 that controls the phase modulation element.
  • the phase difference calculation circuit 101 calculates a phase difference from the interference intensity detected by the photodetector 331.
  • the memory 102 temporarily records the phase difference calculated by the phase difference calculation circuit 101.
  • the phase modulation element drive amount calculation circuit 103 calculates the drive amount of the phase modulation element 309 based on the phase difference calculated by the phase difference calculation circuit 101 and drives the phase modulation element 309.
  • FIG. 12 shows a four-phase recording flow by two-time recording in this embodiment.
  • of Equation 1 are calculated in advance by the photodetector 331 (interference condition learning 1001).
  • the interference intensity is detected by the photodetector 331 (1002), the phase difference is calculated by the phase difference calculation circuit 101 based on the interference condition learned in 1001, and stored in the memory 102 as the phase difference 1 (1003). ). Thereafter, the interference fringe pattern of the signal light 306 and the reference light 307 is recorded on the optical information recording medium 1 (1004).
  • the phase of the signal light 306 is ⁇ / 2 modulated by the phase modulation element 309 (1005).
  • the photodetector 331 detects the interference intensity between the first detection light 328 and the second detection light 334 (1006), and the phase difference calculation circuit 101 calculates the phase difference (1007).
  • the phase difference calculated in 1007 is defined as phase difference 2.
  • the phase difference 1 stored in the memory 102 in 1003 is compared with the phase difference 2 calculated in 1007, and it is determined whether the difference is within a predetermined range (1008).
  • phase modulation element drive amount calculation circuit 103 calculates the drive amount of the phase modulation element 309 (1009), and the processing from 1005 to 1008 is performed. Try again.
  • phase difference detection and phase control in this embodiment are not performed every time one page data is recorded, and processing 1002 to processing 1003 and processing 1006 to processing 1009 are performed every several pages or every several books. Also good.
  • the learning of the interference condition 1001 is not performed at the time of recording, but may be performed at the time of shipment adjustment or initial adjustment, for example.
  • the control of the phase modulation element 309 is recorded in advance. Set the initial value of the condition.
  • the phase difference between the first detection light 328 and the second detection light 334 at the time of the first recording in which the signal point 401 and the signal point 402 are recorded is calculated.
  • the first recording and the second recording can be performed.
  • the method for obtaining the phase difference between the first detection light 328 and the second detection light 334 from the interference intensity detected by the light detector 331 is not limited to the above means, and for example, the first detection light 328 and the second detection light 334. It may be calculated by adding four phases of 0, ⁇ / 2, ⁇ , 3 ⁇ / 2, etc. to either of them and performing a fringe scan.
  • the phase of the signal light is modulated using the phase modulation element 309 disposed in the optical path of the signal light 306, but the phase of the reference light 307 is disposed by arranging the phase modulation element in the optical path of the reference light 307. It is also possible to use a configuration that modulates.
  • phase four-value recording and phase four-value reproduction by two-time recording have been described, but it goes without saying that this control method can be applied to any recording / reproduction method using phase multivalue. Yes.
  • the phase difference between the signal light and the reference light during recording may be controlled to a predetermined value between pages or books.
  • FIG. 13 shows an example of the recording flow at this time.
  • a page or book is recorded (1304), interference intensity detection (1305), and phase difference 2 calculation (1306) are performed.
  • phase difference of signal points between adjacent pages and adjacent books can be controlled to a predetermined value, and inter-page interference and inter-book interference can be suppressed.
  • the phase difference between the oscillator light and the reference light during reproduction may be controlled.
  • the present embodiment is different from the first embodiment in that the non-polarizing beam splitters 326 and 332 that generate the first detection light 328 and the second detection light 334 are arranged near the optical information recording medium, and the reference light 307 A part of the light is used as the second detection light 334.
  • FIG. 14 shows a recording principle in an example of a basic optical system configuration of the optical pickup device 11 in the optical information recording / reproducing apparatus of the present embodiment.
  • Part of the signal light 306 propagated through the relay lens 313 and the spatial filter 314 is reflected by the non-polarizing beam splitter 326.
  • the reflected light beam is used as the first detection light 328.
  • some of the reference light 307 reflected from the mirror 317 is transmitted through the non-polarizing beam splitter.
  • the equalized light beam is used as the second detection light 334.
  • the signal light path from the light source 301 to the non-polarization beam splitter 326 and the reference light path from the light source 301 to the non-polarization beam splitter 332 are generated. It becomes possible to observe and correct a phase difference change between the signal light 306 and the reference light 307 caused by a change in the optical path length due to disturbance such as air fluctuation, external vibration, thermal expansion / contraction.
  • the optical path length from the polarizing beam splitter 326 to the optical detector 331 is equal to the optical path length from the polarizing beam splitter 326 to the optical information recording medium 1, and the optical path length from the polarizing beam splitter 332 to the optical detector 331 is By making the optical path lengths from the polarizing beam splitter 332 to the optical information recording medium 1 equal, the influence of changes in the optical path length due to disturbance generated in the optical path from the polarizing beam splitter 326 and the polarizing beam splitter 332 to the optical information recording medium 1 is suppressed. can do.
  • This embodiment differs from Embodiments 1 and 2 in that a polarizing beam splitter is used instead of the non-polarizing beam splitter.
  • a polarizing beam splitter is used instead of the non-polarizing beam splitter.
  • FIG. 15 shows a recording principle in an example of a basic optical system configuration of the optical pickup device 11 in the optical information recording / reproducing apparatus of the present embodiment.
  • the polarization beam splitter 340 and the polarization direction conversion element 342 are used.
  • the light quantity ratio between the light transmitted through the polarization beam splitter 340 and the reflected light is adjusted.
  • the polarization direction conversion element 316 and the polarization beam splitter 341 are used.
  • the polarization direction conversion element 316 By adjusting the polarization direction of the reference light 307 by the polarization direction conversion element 316, the light quantity ratio between the light transmitted through the polarization beam splitter 341 and the light reflected is adjusted.
  • the reproduction method using phase conjugate light is used as in the first embodiment, and the information on the optical information recording medium 1 is reproduced using the reference light 307 reflected from the mirror 324.
  • the polarization direction conversion element 316 adjusts the polarization of the reference light 307 so that the reference light 307 passes through the polarization beam splitter 341. Further, the polarization direction conversion element 342 adjusts the polarization of the diffracted light 337 so that the diffracted light 337 reproduced from the optical information recording medium 1 passes through the polarization bee splitter 311.
  • the light amounts of the first detection light 328 and the second detection light 334 can be arbitrarily changed.
  • the first detection light 328 and the second detection light 334 having a minimum amount of light necessary for detecting the interference light by the light detector 331 are generated, and all the remaining light is used for recording optical information on the optical information recording medium 1.
  • the light amount loss of the light used for recording can be suppressed and the recording time of the optical information on the optical information recording medium 1 can be shortened as compared with the first embodiment using the non-polarizing beam splitter.
  • the amount of diffracted light 337 reproduced from the optical information recording medium 1 increases. Can be shortened.
  • the first detection light 328 is obtained by the polarization direction conversion element 316 and the polarization direction conversion element 342 only in the first data recording process 1004 and the second data recording process 1010.
  • the light quantity of the second detection light 334 is adjusted to substantially zero, the light quantity loss of the signal light 306 and the reference light 307 used for optical information recording can be eliminated.
  • the present embodiment is different from the second and third embodiments in that the configuration of the polarization direction conversion element 316 and the polarization direction conversion element 342 is changed so that only part of the signal light 306 and the reference light 307 is ejected and the first detection is performed. This is a point for generating light and second detection light.
  • the light amount loss of the signal light 306 and the reference light 307 used for recording can be eliminated from the first embodiment, and the recording time of optical information on the optical information recording medium 1 can be shortened.
  • the phase difference between the first detection light 328 and the second detection light 334 can be controlled in real time.
  • FIG. 16 shows an example of the configuration of the polarization direction conversion elements 316 and 342 in the present embodiment.
  • the inner 1502 is made of, for example, a half-wave plate, and thus the polarization direction of the transmitted light changes.
  • FIG. 17A shows a configuration of a cross-sectional portion of the signal light 306 after being modulated by the spatial light modulator 312 in the present embodiment.
  • the signal light 306 is made larger than the signal light 306A to which phase information is added by the spatial light modulator 312, and the signal light 306B to which a fixed phase is added is provided on the outer periphery of the signal light 306A.
  • FIG. 17B shows how the first detection light 328 is generated in the present embodiment.
  • the signal light 306 ⁇ / b> B is reflected by the polarization beam splitter 340 because it passes through the outer peripheral portion 1501 of the polarization direction conversion element 342.
  • the signal light 306B reflected by the polarization beam splitter 340 is used as the first detection light 328.
  • the signal light 306 ⁇ / b> A passes through the inside 1502 of the polarization direction conversion element 342, and thus passes through the polarization beam splitter 340 and enters the optical information recording medium 1.
  • FIG. 17C shows how the second detection light is generated in the present embodiment.
  • the reference light 307 is separated into a reference light 307A and a reference light 307B.
  • the reference light 307 B that is not used for optical information recording passes through the outer peripheral portion 1501 of the polarization direction conversion element 316 and is therefore reflected by the polarization beam splitter 341.
  • the reference light 307B reflected by the polarizing beam splitter 341 is used as the second detection light 334.
  • the reference light 307 A used for optical information recording passes through the inside 1502 of the polarization direction conversion element 316, passes through the polarization beam splitter 341, and enters the optical information recording medium 1.
  • FIG. 18 shows an example of the relationship between the light receiving unit 801 of the photodetector 331 and the first detection light 328 and the second detection light 334 incident on the photodetector 331 in this embodiment.
  • phase difference between the first detection light and the second detection light is controlled based on the interference intensity of the portion that does not contribute to the optical information recording, even when the phase information is added to the signal light 306 by the spatial light modulator 312.
  • the phase difference between the first detection light 328 and the second detection light 334 can be calculated and controlled. Therefore, the phase difference between the first detection light 328 and the second detection light 334 can be controlled in real time during optical information recording.
  • the component configuration for ejecting the first detection light 328 and the second detection light 334 and the detection method by the detector 331 are not limited to those shown in FIGS.
  • the present embodiment is different from the first embodiment in that instead of generating the first detection light 328 and the second detection light 334 in front of the optical information recording medium 1 and detecting the interference caused by them by the photodetector 331, This is a point of detecting the interference between the signal light 306 transmitted through the optical information recording medium 1 and the reference light 307.
  • the light amount loss of the signal light 306 and the reference light 307 used for recording can be eliminated compared to the first embodiment, so that the recording time of optical information on the optical information recording medium 1 can be shortened.
  • the phase difference change can be corrected with respect to the second and third embodiments, the accuracy of the phase difference control can be improved.
  • FIG. 19 shows a recording principle in an example of a basic optical configuration of the optical pickup device 11 in the optical information recording / reproducing apparatus of the present embodiment.
  • the photodetector 331 detects the interference intensity between the signal light 306 and the reference light 307 transmitted through the optical information recording medium 1 during recording.
  • the signal light 306 transmitted through the optical information recording medium 1 enters the photodetector 331 through the lens 340, the mirror 341, and the non-polarizing beam splitter 342.
  • the reference light 307 that has passed through the optical information recording medium 1 is reflected by the mirror 324, reflected by the non-polarized beam splitter 342, enters the photodetector 331, and overlaps with the signal light 306. Note that the angle of the mirror 324 can be adjusted by an actuator 323.
  • the mirror 324 is adjusted by the actuator 323 so that the reference light 307 enters the optical information recording medium 1. Similar to the first embodiment, a reproduction method using phase conjugate light is used, and information on the optical information recording medium 1 is reproduced using the reference light 307 reflected from the mirror 324.
  • the recording time of optical information on the optical information recording medium 1 can be shortened.
  • the phase difference change in the signal light optical path after the lens 315 and the reference light optical path after the mirror 319 that cannot be corrected in the first embodiment can be corrected, and the accuracy of the phase difference control between the signal light 306 and the reference light 307 can be corrected. It leads to improvement.
  • the present embodiment is different from the first embodiment in that the optical path of the first detection light 328 or the second detection light 334 is divided into at least two spatially divided phase plates 1701 that add at least two kinds of phases to transmitted light. It is a point to be placed inside.
  • ⁇ can be calculated without obtaining the values of
  • the phase difference control can be speeded up.
  • FIG. 20 shows an example of the divided phase plate 1701 in the present embodiment.
  • a divided phase plate 1701 that is spatially divided into four and adds four types of phases (0, ⁇ / 2, ⁇ , 3 ⁇ / 2) is disposed in the optical path of the first detection light 328.
  • the first detection light 328 transmitted through the divided phase plate 1701 is divided into four regions to which different phases are added.
  • FIG. 21 shows an example of the relationship between the light receiving unit of the photodetector 331 and the first detection light 328 and the second detection light 334 incident on the photodetector 331 in this embodiment.
  • the photodetector 331 includes four light receiving units 801, 802, 803, and 804, and the light receiving unit 801 receives interference between the region 1801 to which the phase 0 is added and the second detection light 334 in the first detection light 328.
  • the unit 802 includes interference between the second detection light 334 and the region 1802 to which the phase ⁇ / 2 is added in the first detection light 328, and the light receiving unit 803 includes the region 1803 to which the phase ⁇ is added from the first detection light 328.
  • the light receiving unit 804 detects interference between the second detection light 334 and the interference between the second detection light 334 and the region 1804 added with the phase 3 ⁇ / 2 in the first detection light 328.
  • the value obtained by subtracting the interference intensity detected by the light receiving unit 802 from the interference intensity detected by the light receiving unit 801 is I 1
  • the value obtained by subtracting the interference intensity detected by the light receiving unit 804 from the interference intensity detected by the light receiving unit 803 is I 2 .
  • Number 2 is a formula representing the first detection light 328 a phase difference ⁇ of the second detection light 334 at I 1 and I 2, can be calculated ⁇ in accordance with the formula from I 1 and I 2.
  • the phase modulation element 309 is controlled so that the difference in ⁇ between the first recording and the second recording becomes ⁇ / 2, thereby correcting the phase difference change between the signal light and the reference light. be able to.
  • ⁇ can be calculated without obtaining the values of
  • the phase difference control can be speeded up.
  • the configuration using the spatially divided phase plate 1701 is described.
  • the number of spatial divisions of the divided phase plate 1701 may be two or more.
  • the number of light receiving units may be two or more.
  • the divided phase plate 1701 may be arranged in the optical path of the second detection light 334 so that a phase is added to the second detection light 334.
  • the present embodiment is different from the first embodiment in that the photodetector 331 is an imaging device such as a CMOS image sensor or a CCD image sensor, and the entire interference light of the first detection light 328 and the second detection light 334 is imaged.
  • phase control is performed using a three-dimensional array type phase modulation element 309.
  • FIG. 22 shows an example of the relationship between the light receiving unit 801 of the photodetector 331 and the first detection light 328 and the second detection light 334 incident on the photodetector 331 in this embodiment.
  • the photodetector 331 is an imaging device such as a CMOS image sensor or a CCD image sensor, and images the entire interference light of the first detection light 328 and the second detection light 334.
  • the interference light is divided into a plurality of regions, and phase differences ⁇ 1 to ⁇ N between the first detection light 328 and the second detection light 334 are calculated in each region (N is the interference light) Division number).
  • phase modulation element 309 controls each of the phase differences ⁇ 1 to ⁇ N to a predetermined value.
  • the phase modulation element 309 is, for example, a two-dimensional array type element such as a phase modulation type spatial light modulator or a deformable mirror, so that an arbitrary position in the plane of the signal light 306 or the reference light 307 can be obtained. Enable to add phase.
  • the in-plane distribution of the phase difference between the first detection light 328 and the second detection light 334 can be calculated, and the phase difference can be controlled for each arbitrary location in the plane.
  • the in-plane wavefront deviation of the signal light 306 and the reference light 307 can be corrected.
  • the photodetector 331 may be configured to detect a phase difference distribution in the plane of the first detection light 328 and the second detection light 334 by arranging a plurality of elements such as a photodetector for detecting the light intensity in the plane.
  • This embodiment is different from the first embodiment in that light obtained by adding phase information to the signal light 306 by the spatial light modulator 306 is incident on the photodetector 331.
  • the phase information added by the spatial light modulator 312 to the signal light 306 can be measured during recording, and the recording quality can be further improved with respect to the first embodiment.
  • FIG. 23 shows a recording principle in an example of a basic optical system configuration of the optical pickup device 11 in the optical information recording / reproducing apparatus of the present embodiment.
  • a part of the signal light 306 transmitted through the polarization direction changing element 310 is reflected by the non-polarizing beam splitter 326 and used as the first detection light 328.
  • the first detection light 328 is reflected by the non-polarizing beam splitter 330 and enters the photodetector 331.
  • the signal light 306 that has passed through the non-polarizing beam splitter 326 passes through the polarizing beam splitter 311, enters the spatial light modulator 312, and page data is added by the spatial light modulator 312.
  • the signal light 306 to which page data is added by the spatial light modulator 312 is reflected by the polarization beam splitter 311, and part of the light is reflected by the non-polarization beam splitter 332.
  • the light reflected by the non-polarization beam splitter 332 is used as the second detection light 334, and the second detection light 334 passes through the non-polarization beam splitter 330 and enters the photodetector 331.
  • the photodetector 331 is an imaging device such as a CMOS image sensor or a CCD image sensor.
  • each pixel of the spatial light modulator 312 adds the phase added to the signal light 306 from the interference intensity of the first detection light 328 and the second detection light 334 detected by the photodetector 331. It becomes possible to measure at the time of recording.
  • the measurement result is compared with the information signal sent from the controller 89 to the spatial light modulator 312 via the signal generation circuit 86, and the spatial light is adjusted so that the difference between the measurement result for each pixel and the information signal is equal to or less than a predetermined value.
  • the modulator 312 may be controlled, or variation information between the measurement result and the information signal is recorded on the optical information recording medium 1, and signal processing is performed based on the variation information between the measurement result and the information signal during reproduction. You can go.
  • the spatial light modulator 312 of the present embodiment is not limited to the one that adds a phase binary value, and may be one that adds, for example, phase quaternary or more phase multilevel information.
  • the present embodiment is different from the second embodiment in that the photodetector 331 includes a plurality of light receiving surfaces 801, and the optical axes of the first detection light 328 and the second detection light 334 incident on the light receiving unit 801 are different. Are inclined at a predetermined angle.
  • FIG. 24A is a diagram showing an example of the relationship between the photodetector 331, the first detection light 328, and the second detection light in the optical information recording / reproducing apparatus of the present embodiment.
  • the first detection light 328 reflected by the non-polarizing beam splitter 330 enters the photodetector 331 perpendicularly.
  • the second detection light 334 transmitted through the non-polarizing beam splitter 330 is incident obliquely on the photodetector 331.
  • FIG. 24B is a diagram showing an example of the relationship between the light receiving unit 801 of the photodetector 331, the first detection light 328, and the second detection light in the optical information recording / reproducing apparatus of the present embodiment.
  • the wavefront of the first detection light and the wavefront of the second detection light are received by the light receiving unit 801 of the photodetector 331 in a state where the wavefronts of the first detection light and the second detection light are inclined at a predetermined angle, and interference fringes between the first detection light 328 and the second detection light 334 are received.
  • the light receiving unit 801 includes a plurality of light receiving units.
  • the light receiving unit receives the bright portions of the interference fringes of the first detection light 328 and the second detection light 334, and includes the first detection light 328 and the second detection light 334. There is a light receiving portion that receives a dark portion of an interference fringe.
  • the contrast of the interference fringes between the first detection light and the second detection light can be measured by the photodetector 331, and the first phase modulation element 309 can adjust the contrast to maximize the contrast.
  • the optical path length difference between the first detection light 328 and the second detection light 334 it is possible to record a hologram on the optical information recording medium 1 with high coherence between the signal light 306 and the reference light 307. Become. Therefore, a strong interference fringe pattern is recorded on the optical information recording medium 1, and the amount of diffracted light 337 during reproduction can be increased, so that high reproduction performance can be obtained.
  • the configuration of the light receiving surface 801 of the photodetector 331 of the present embodiment is not limited to the above. Further, the light incident on the photodetector 331 obliquely is not limited to the second detection light 334, and the first detection light 328 may be incident obliquely on the photodetector 331.
  • the present embodiment is not limited to phase multilevel hologram recording.
  • phase multilevel hologram recording even in amplitude multilevel hologram recording, it is possible to obtain high reproduction performance by increasing the coherence between the signal light 306 and the reference light 307. is there.
  • phase multilevel hologram recording / reproducing apparatus and the phase multilevel hologram recording / reproducing method, it is possible to correct the phase difference change between the signal light and the reference light during recording, and stable phase multilevel Information can be reproduced.
  • a phase control unit that controls the phase of reference light or signal light, light that has passed through the phase control unit, and a light detection unit that detects interference intensity of light that has not passed through the phase control unit
  • a phase difference calculation unit that calculates a phase difference based on the interference intensity detected by the light detection unit
  • a phase difference control amount calculation unit that calculates a phase difference control amount based on the phase difference
  • phase multi-value recording is performed by performing hologram recording twice on the same portion of the hologram recording medium, and the above-mentioned level is recorded during the first hologram recording. Control the phase difference during the second hologram recording so that the difference between the first phase difference control step for controlling the phase difference and the phase difference controlled in the first phase control step is within a predetermined range.
  • An optical information recording / reproducing method comprising: a second phase difference control step.
  • the optical information recording / reproducing method includes the phase difference control step of controlling the phase difference every time a predetermined number of pages or a predetermined number of books are recorded.
  • a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.
  • SYMBOLS 1 Optical information recording medium, 11 ...
  • Optical pick-up apparatus 101 ... Phase difference calculation circuit, 102 ... Memory, 103 ... Phase modulation element drive amount calculation circuit, 301 ... Light source, 302 ... Collimating lens, 303 ... Shutter, 304 ... Half-wave plate, 305 ... Polarizing beam splitter, 306 ... Signal light, 307 ... Reference light, 308 ... Beam Expander, 309 ... phase modulation element, 310 ... polarization direction conversion element, 311 ... polarization beam splitter, 312 ... spatial light modulator, 313 ... relay lens, 314 ... spatial filter 315 ... objective lens, 316 ...
  • Polarization direction conversion element 317 ... mirror, 319 ... mirror, 320 ... actuator, 321 ... lens, 322 ... , 323 ... Actuator, 324 ... Mirror, 325 ... Photodetector, 326 ... Unpolarized beam splitter, 328 ... First detection light, 329 ... Mirror, 330 ... Non-polarizing beam splitter, 331 ... photodetector, 332 ... non-polarizing beam splitter, 334 ... second detection light, 337 ... diffracted light, 338 ... oscillator light, 339 ... polarized light 340: Polarization beam splitter, 341: Polarization beam splitter, 342: Polarization direction conversion element, 801: Light receiving unit, 802 ... Light receiving unit, 803 ... Light receiving unit, 804 ..Light receiving part, 1701 ... Divided phase plate

Abstract

L'invention concerne une technique d'enregistrement d'informations optiques, selon laquelle un changement de différence de phase entre une lumière de signal et une lumière de référence pendant l'enregistrement est corrigé pendant l'enregistrement pour enregistrer un hologramme de haute qualité et, de ce fait, des informations de valeurs multiples de phase peuvent être reproduites de façon stable. Ce dispositif d'enregistrement d'informations optiques enregistre, en tant qu'hologramme dans un support d'enregistrement d'hologramme, une frange d'interférence obtenue en causant une interférence de lumière de référence et de lumière de signal, qui comprend : une source de lumière qui émet une lumière; un élément de division de flux lumineux qui divise la lumière émise depuis la source de lumière en une première lumière et une seconde lumière; une unité de détection de lumière qui reçoit la première lumière et la seconde lumière et détecte une intensité d'interférence; une unité de commande de phase qui calcule la différence de phase entre la première lumière et la seconde lumière à partir de l'intensité d'interférence détectée par l'unité de réception de lumière, et commande au moins la phase de la seconde lumière; et un modulateur spatial de lumière qui ajoute des informations de valeurs multiples de phase à la seconde lumière.
PCT/JP2015/075527 2015-09-09 2015-09-09 Dispositif d'enregistrement d'informations optiques, dispositif d'enregistrement/reproduction d'informations optiques, et procédé d'enregistrement d'informations optiques WO2017042900A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000099982A (ja) * 1998-09-24 2000-04-07 Sanyo Electric Co Ltd 光ピックアップ装置及びそれを用いた光学記録媒体駆動装置
JP2003178460A (ja) * 1998-02-27 2003-06-27 Optware:Kk 光情報記録装置および光情報再生装置
JP2012027996A (ja) * 2010-07-28 2012-02-09 Hitachi Consumer Electronics Co Ltd 光情報記録再生装置及び再生装置
JP2013182653A (ja) * 2012-03-05 2013-09-12 Hitachi Consumer Electronics Co Ltd 光情報再生装置、光情報記録装置及び光情報記録方法
JP2014002823A (ja) * 2012-06-20 2014-01-09 Hitachi Consumer Electronics Co Ltd 光情報記録再生装置および光情報記録再生方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003178460A (ja) * 1998-02-27 2003-06-27 Optware:Kk 光情報記録装置および光情報再生装置
JP2000099982A (ja) * 1998-09-24 2000-04-07 Sanyo Electric Co Ltd 光ピックアップ装置及びそれを用いた光学記録媒体駆動装置
JP2012027996A (ja) * 2010-07-28 2012-02-09 Hitachi Consumer Electronics Co Ltd 光情報記録再生装置及び再生装置
JP2013182653A (ja) * 2012-03-05 2013-09-12 Hitachi Consumer Electronics Co Ltd 光情報再生装置、光情報記録装置及び光情報記録方法
JP2014002823A (ja) * 2012-06-20 2014-01-09 Hitachi Consumer Electronics Co Ltd 光情報記録再生装置および光情報記録再生方法

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