WO2016020994A1

WO2016020994A1 - Otical information recording device and optical information reproduction device

Info

Publication number: WO2016020994A1
Application number: PCT/JP2014/070666
Authority: WO
Inventors: 悠介中村; 誠保坂
Original assignee: 株式会社日立製作所
Priority date: 2014-08-06
Filing date: 2014-08-06
Publication date: 2016-02-11
Also published as: JPWO2016020994A1

Abstract

The present invention addresses the problem of obtaining an optical information recording/reproduction device and an optical information recording/reproduction method with which the media consumption amount of an oscillator page can be reduced significantly in comparison with the media consumption amount of a data page. To solve this problem, this optical information recording device, which uses holography to record information on an optical information recording medium, is characterized in that interference fringes of a signal light radiated from a signal light radiation unit and a reference light radiated from a reference light radiation unit are multiplex-recorded as a signal light hologram on a prescribed region of an optical information recording medium, and interference fringes of an oscillator light radiated from an oscillator light radiation unit and a reference light radiated from the reference light radiation unit are recorded as an oscillator hologram.

Description

Optical information recording apparatus and optical information reproducing apparatus

The present invention relates to a technique for recording information on an optical information recording medium using holography and reproducing information from the optical information recording medium.

As a hologram recording / reproducing technique, there is, for example, WO 2004-102542 (Patent Document 1). In this publication, in one spatial light modulator, light from an inner pixel is signal light, light from an outer ring-shaped pixel is reference light, and both light beams are condensed on an optical recording medium with the same lens. An example is described in which a shift multiplexing method is used in which a hologram is recorded by causing signal light and reference light to interfere with each other in the vicinity of the focal plane of the lens.

Further, for example, as described in Non-Patent Document 1, “However, to detect the phase in a signal beam, the signal should interfere with an additional beam on an imager for converting the phase into intensity information." In order to detect, it is necessary to interfere with the signal light and another light, `` In 「the DRH, a signal beam with data to be recorded and a phantom beam without signal information are holographically multiplexed at the same spot of the medium, and then these holograms are read out simultaneously from the medium and the diffracted beams propagate in the same optical path toward the imager for yielding the interference fringe. '(double-referential holography (DRH)) There is a description of a phase recording / reproducing method in which light interferes.

WO2004-102542

However, in the method described in Non-Patent Document 1, one phantom light is required for reproducing one data page, and the consumption of the recording medium is large.

The above problem is solved by the following configuration, for example.

In an optical information recording apparatus that records information on an optical information recording medium using holography, a light source that generates reference light, signal light, and oscillator light, and a signal light modulation unit that adds information to the signal light generated by the light source A signal light irradiation unit that irradiates the optical information recording medium with the signal light modulated by the signal light modulation unit; an oscillator light irradiation unit that irradiates the optical information recording medium with the oscillator light generated by the light source; A reference light irradiation unit that irradiates the optical information recording medium with the reference light generated by the light source, the signal light emitted from the signal light irradiation unit, and the reference light emitted from the reference light irradiation unit Are recorded as a signal light hologram in a predetermined area of the optical information recording medium, the oscillator light irradiated from the oscillator light irradiation unit, and the reference light irradiation unit irradiated from the reference light irradiation unit Recording the interference fringes between the light as the oscillator hologram.

According to the present invention, it is possible to greatly suppress the media consumption of the oscillator page (phantom light) compared to the consumption of the recording medium of the data page, and to realize a highly efficient phase recording / reproducing method. Become.

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 the Example of the signal generation circuit in an optical information recording / reproducing apparatus Schematic showing the Example of the signal processing circuit in an optical information recording / reproducing apparatus Schematic diagram showing an example of the operation flow of book recording Schematic showing an example of the operation flow of book reproduction Schematic representing an example of oscillator page recording Schematic diagram representing an example of data page recording Schematic representing an embodiment of oscillator page and data page playback Schematic representing an example of the page structure in a book Schematic showing the Example of the relationship between the reference beam angle for oscillators, and the reference beam angle for pages Schematic representing an example of the configuration of a half mirror Schematic representing an example of the configuration of a half mirror Schematic representation of an example oscillator page Schematic showing an embodiment of a pickup in an optical information recording / reproducing apparatus Schematic representing an embodiment of oscillator page and data page playback Schematic showing an embodiment of a pickup in an optical information recording / reproducing apparatus Schematic representing an example of oscillator page recording Schematic representing an embodiment of oscillator page and data page playback Schematic showing an embodiment of a pickup in an optical information recording / reproducing apparatus Schematic representing an embodiment of oscillator page and data page playback Schematic showing an example of the operation flow of book reproduction Schematic showing an embodiment when recording a phase difference detection pattern Schematic showing an embodiment when reproducing a phase difference detection pattern Schematic representing an example of the relationship between phase delay and evaluation index Schematic representing an example of the page structure in a book Schematic showing an example of the operation flow of book reproduction Schematic showing an embodiment of signal point arrangement of amplitude modulation and phase modulation Schematic representing an example of an amplitude modulation and phase modulation data page

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a recording / reproducing apparatus that performs at least one process of recording or reproducing digital information from an optical information recording medium using holography.

The optical information recording / reproducing device 10 is connected to an external control device 91 via an input / output control circuit 90. In the case of recording, 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. When reproducing, 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 reproduction reference light optical system 12, a cure optical system 13, a disk rotation angle detection optical system 14, a position detection optical system 15, and a rotation motor 50. The recording medium 1 can be rotated by a rotary motor 50.

The pickup 11 plays a role of emitting reference light and signal light to the optical information 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.

When reproducing the information recorded on the optical information recording medium 1, the reproduction reference light optical system 12 generates a light wave that causes the reference light emitted from the pickup 11 to enter the optical information recording medium in a direction opposite to that during recording. Generate. 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 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. When adjusting the optical information recording medium 1 to a predetermined rotation angle, 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.

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 optical information recording medium 1, and the position is controlled via the access control circuit 81.

By the way, 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.

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.

Also, the pickup 11, the cure optical system 13, the disk rotation angle detection optical system 14, and the position detection optical system 15 may be simplified by combining several optical system configurations or all optical system configurations.

FIG. 2 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, it enters a PBS (Polarization Beam Splitter) prism 205.

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 at least one of phase or intensity information is added by the spatial light modulator 212 is reflected by the PBS prism 211 and propagates through the relay lens 213 and the spatial filter 214. Thereafter, the signal light is condensed on the optical information recording medium 1 by the objective lens 215.

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 optical information 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.

In this way, the signal light and the reference light 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 recorded by writing this pattern on the recording medium. To do. Moreover, since the incident angle of the reference light incident on the optical information recording medium 1 can be changed by the galvanometer mirror 219, recording by angle multiplexing is possible.

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. .

FIG. 3 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 optical information recording medium 1 and the light beam transmitted through the optical information recording medium 1 is transmitted to the galvanometer mirror 226 via the lens 223 and the lens 224 as described above. Incident. The galvanometer mirror 226 adjusts the angle by the actuator 225, and the light that has passed through the lens 224 and the lens 223 enters the optical information recording medium 1 as reproduction reference light.

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 228, and the recorded signal can be reproduced. As the photodetector 228, for example, an image sensor such as a CMOS image sensor or a CCD image sensor can be used, but any element may be used as long as the data page can be reproduced.

FIG. 4 shows an operation flow of recording and reproduction in the optical information recording / reproducing apparatus 10. Here, a flow relating to recording / reproduction using holography in particular will be described.

FIG. 4A shows an operation flow from the insertion of the optical information recording medium 1 into the optical information recording / reproducing apparatus 10 until the preparation for recording or reproduction is completed. FIG. FIG. 4C shows an operation flow until information is recorded on the information recording medium 1, and FIG. 4C shows an operation flow until the information recorded on the optical information recording medium 1 is reproduced from the ready state.

When a medium is inserted as shown in FIG. 4A (401), the optical information recording / reproducing apparatus 10 discriminates whether the inserted medium is a medium for recording or reproducing digital information using holography, for example. (402).

As a result of disc discrimination, when it is determined that the optical information recording medium records or reproduces digital information using holography, the optical information recording / reproducing apparatus 10 reads control data provided on the optical information recording medium (403). ), For example, information relating to the optical information recording medium and information relating to various setting conditions during recording and reproduction, for example.

After reading the control data, various adjustments according to the control data and learning processing (404) related to the pickup 11 are performed, and the optical information recording / reproducing apparatus 10 is ready for recording or reproduction (405).

As shown in FIG. 4B, the operation flow from the ready state to recording information is as follows. First, data to be recorded is received (411), and information corresponding to the data is received from the spatial light modulator in the pickup 11. To send.

Thereafter, various recording learning processes such as optimization of the power of the light source 301 and optimization of exposure time by the shutter 303 are performed in advance so that high-quality information can be recorded on the optical information recording medium (412). ).

Thereafter, in the seek operation (413), the access control circuit 81 is controlled to position the pickup 11 and the cure optical system 13 at predetermined positions on the optical information recording medium. When the optical information recording medium 1 has address information, it reproduces the address information, checks whether it is positioned at the target position, and calculates the amount of deviation from the predetermined position if it is not positioned at the target position. And repeat the positioning operation.

Thereafter, a predetermined region is pre-cured using the light beam emitted from the cure optical system 13 (414), and data is recorded using the reference light and signal light emitted from the pickup 11 (415).

After recording the data, post cure is performed using the light beam emitted from the cure optical system 13 (416). Data may be verified as necessary.

As shown in FIG. 4C, the operation flow from the ready state to the reproduction of the recorded information is as follows. First, in the seek operation (421), the access control circuit 81 is controlled, and the pickup 11 and the reproduction reference light are reproduced. The position of the optical system 12 is positioned at a predetermined position on the optical information recording medium. When the optical information recording medium 1 has address information, it reproduces the address information, checks whether it is positioned at the target position, and calculates the amount of deviation from the predetermined position if it is not positioned at the target position. And repeat the positioning operation.

Thereafter, reference light is emitted from the pickup 11, information recorded on the optical information recording medium is read (422), and reproduction data is transmitted (423).

FIG. 5 is a block diagram of the signal generation circuit 86 of the optical information recording / reproducing apparatus 10.

When the input of user data to the output control circuit 90 is started, the input / output control circuit 90 notifies the controller 89 that the input of user data has started. In response to this notification, the controller 89 instructs the signal generation circuit 86 to record data for one page input from the input / output control circuit 90. A processing command from the controller 89 is notified to the sub-controller 501 in the signal generation circuit 86 via the control line 508. Upon receiving this notification, the sub-controller 501 controls each signal processing circuit via the control line 508 so that the signal processing circuits are operated in parallel. First, the memory control circuit 503 is controlled so that user data input from the input / output control circuit 90 via the data line 509 is stored in the memory 502. When the user data stored in the memory 502 reaches a certain amount, the CRC calculation circuit 504 performs control to convert the user data into CRC. Next, the scramble circuit 505 scrambles the CRC-converted data by adding a pseudo-random data sequence, and the error correction encoding circuit 506 performs error correction encoding by adding a parity data sequence. Finally, the pickup interface circuit 507 reads out the error correction encoded data from the memory 502 in the order of the two-dimensional data on the spatial light modulator 212, adds a reference marker at the time of reproduction, Two-dimensional data is transferred to the spatial light modulator 212. This two-dimensional data is called a data page.

FIG. 6 is a block diagram of the signal processing circuit 85 of the optical information recording / reproducing apparatus 10.

When the photodetector 228 in the pickup 11 detects the image data, the controller 89 instructs the signal processing circuit 85 to reproduce the data for one page input from the pickup 11. A processing command from the controller 89 is notified to the sub-controller 601 in the signal processing circuit 85 via the control line 611. Upon receiving this notification, the sub-controller 601 controls each signal processing circuit via the control line 611 so as to operate each signal processing circuit in parallel. First, the memory control circuit 603 is controlled to store the image data input from the pickup 11 via the pickup interface circuit 610 via the data line 612 in the memory 602. When the data stored in the memory 602 reaches a certain amount, the image position detection circuit 609 performs control to detect a marker from the image data stored in the memory 602 and extract an effective data range. Next, using the detected marker, the image distortion correction circuit 608 performs distortion correction such as image inclination, magnification, and distortion, and controls to convert the image data into the expected two-dimensional data size. Each bit data of a plurality of bits constituting the size-converted two-dimensional data is decoded by the decoding circuit 607 by determining multi-value data, and control is performed so that the data is stored in the memory 602 in a sequence of output reproduction data. . Next, the error correction circuit 606 corrects the error included in each data string, the scramble release circuit 605 releases the scramble to add the pseudo random number data string, and then the CRC calculation circuit 604 causes an error in the user data on the memory 602. Check not included. Thereafter, the user data is transferred from the memory 602 to the input / output control circuit 90.

Here, the principle of phase recording / reproducing which is a feature of this embodiment will be described. In the case of the data page subjected to amplitude modulation (intensity modulation and luminance modulation) shown in FIG. 31A, information can be detected by the photodetector 228 as described above. However, in the case of the phase-modulated data page shown in FIG. 31 (b), since the amplitude is uniform, the photodetector 228 that integrates and detects light over time cannot directly obtain phase information. . Therefore, the oscillator light having uniform luminance and uniform phase shown in FIG. 31C and the reproduced data page are caused to interfere on the photodetector 228. As a result, pixels having the same phase between the oscillator light and the reproduced data page are detected as intensified and high luminance, and pixels in the opposite phase are detected as weak and low luminance. In this way, phase information can be converted into intensity information and detected. The same applies to phase multilevel modulation and amplitude phase multilevel modulation.

However, the problem with this method is the wavefront shift between the reproduced data page and the oscillator light. If the wavefront deviation occurs, it is impossible to determine whether the detected information is recorded information or due to the wavefront deviation, so that the reading accuracy is lowered. Research has also revealed that this wavefront shift is caused mainly by expansion and contraction due to the temperature of the recording medium.

Therefore, first, information is recorded as a data hologram by the interference between the data page and the data reference beam. Next, the oscillator light is recorded as an oscillator page by an interference with an oscillator reference light having a reference light angle different from that of the data page. As a result, even if the medium expands and contracts due to temperature or the like, each hologram expands and contracts in the same manner, so that the reproduction light is distorted in the same manner. Therefore, by simultaneously reproducing the oscillator hologram and the data hologram, it is possible to cause interference by the photodetector 228 without wavefront deviation, and phase information can be detected as intensity with high accuracy.

In addition, since the angle multiplexing method is used to record a large number of data pages at the same position, it is not necessary to record the oscillator page for each data page, and the consumption of the recording medium can be extremely reduced. The above can be applied not only to the angle multiplexing method but also to any method that multiplexes a plurality of information at the same location, such as a phase code multiplexing method, a wavelength multiplexing method, and a polarization multiplexing method.

This oscillator page can be generated by displaying information on the spatial light modulator 212 with uniform luminance and uniform phase. The uniform brightness and uniform phase are convenient for interference with the data page during reproduction, but are not limited. Further, the oscillator light may be generated and recorded by another optical system.

The data recording process (415) using this method will be described in detail. FIG. 7 is a processing flow of the data recording process (415), FIG. 9 is a schematic diagram when recording an oscillator page, and FIG. 10 is a schematic diagram when recording a data page.

At the time of recording, the galvanometer mirror 219 is set to the reference light incident angle for the oscillator page recording (701), and the interference fringes between the signal light 901 of the oscillator page and the reference light 902 for the oscillator are recorded on the optical information recording medium 1 as a hologram. (702). Next, the galvanometer mirror 219 is set to the reference light incident angle for data page recording (703), and the interference fringes between the signal light 1001 of the data page and the data reference light 1002 are recorded on the optical information recording medium 1 as a hologram. (704). The

processes

703 and 704 are performed on all data pages in one book (705). Through the above processing, one oscillator page and a plurality of data pages are recorded in one book.

Next, the data reproduction process (422) using this method will be described in detail. FIG. 8 is a processing flow of the data reproduction process (422), and FIG. 11 is a schematic diagram at the time of reproduction.

At the time of reproduction, the galvanometer mirror 219 is set to the same incident angle as that at the time of recording the oscillator page (801), and the reproduction reference beam 1101 is irradiated to the optical information recording medium 1. The light transmitted through the medium passes through the lens 223, is reflected by the half mirror 227, becomes 1102, and the oscillator reference light 1104 that passes through the lens 223 again irradiates the optical information recording medium 1. The oscillator reference light 1104 is a traveling wave in the opposite direction of the oscillator reference light 902, and the oscillator reference light 1104 is diffracted to reproduce the reproduction light 1105 of the oscillator page and propagate to the photodetector 228.

On the other hand, the light 1103 transmitted through the half mirror 227 passes through the lens 224, is reflected by the galvano mirror 226, becomes 1106, and the data reference light 1107 that passes through the

lenses

224 and 223 irradiates the optical information recording medium 1. The data reference beam 1107 is a traveling wave in the reverse direction of the data reference beam 1002, and the data reference beam 1107 is diffracted to reproduce the data page reproduction beam 1108 and propagate it to the photodetector 228. Therefore, the galvanometer mirror 226 must be controlled so that the data reference beam 1107 has the same incident angle as the data reference beam 1002 (802).

Since the polarization state of the oscillator reference light 1104 and the data reference light 1107 are the same, the polarization state of the oscillator page reproduction light 1105 and the data page reproduction light 1108 propagated to the photodetector 228 is the same and interferes. Phase information can be detected as intensity. (803). The processes of 802 and 803 are performed on all data pages in one book (804).

According to the above circuit configuration and processing procedure, an optical information recording / reproducing apparatus capable of causing interference on the photodetector 228 without wavefront deviation between the oscillator page and the data page and capable of detecting phase information as intensity is realized. can do. In addition, since a plurality of data pages can be reproduced from one oscillator page, consumption of the recording medium by the oscillator page can be suppressed extremely small.

In the control of the galvanometer mirror 219 and the galvanometer mirror 226, “the same incident angle” is used. However, in order to compensate for expansion and contraction of the medium, the reference beam incident angle may be changed between recording and reproduction. May be read as “incident angle required to reproduce the oscillator page or data page”.

In the above description, an example in which the oscillator page is recorded first is shown, but the order is not limited. If FIG. 12A is the arrangement shown in FIGS. 9 and 10, the arrangement shown in FIGS. 12B, 12C, and 12D may be used. With the arrangement shown in FIG. 12B, the oscillator page can be arranged at an angle with low reference light angle selectivity, so that an angle adjustment accuracy margin with respect to the oscillator page can be ensured. By arranging the oscillator page at an angle that becomes the center of the book as shown in FIG. 12C, the reference light angle difference between the oscillator page and the data page can be reduced, and therefore the possibility of wavefront deviation can be suppressed. This is because if the reference light angle is different, the influence of the expansion and contraction of the medium changes, and there is a possibility of causing a wavefront shift. From this point of view, if a plurality of oscillator pages are recorded in the book as shown in FIG. 12D, it is possible to select and use the oscillator page with the smallest wavefront deviation. When recording a plurality of oscillator lights, it is possible to simplify each process by inserting them at regular intervals, such as inserting one oscillator light into 10 pages.

The relationship between the reference light incident angle and the signal light incident angle corresponding to FIGS. 12 (a) to 12 (d) is shown in FIGS. 13 (a) to 13 (d). The one-dot chain line in the figure indicates the optical axis of the reference light. The configuration of the half mirror 227 is shown in FIGS. As shown in the figure, the half mirror 227 is not formed of a half mirror on the entire surface, but has a reflectance of about 50% only in the region 1401 where the oscillator reference light is collected, and the data reference light is collected. The region 1402 to be transmitted is configured to be almost transparent. Note that the transmittance of the region 1401 may be freely changed according to the design of the optical system. Since the region where the oscillator reference light is collected depends on the incident angle of the oscillator reference light, it must be changed depending on the arrangement of the oscillator pages. If it is dynamically changed, the reflection region can be electrically changed by a device such as a dimming mirror, or mechanically moved to make it variable. In addition, when angle multiplexing is also performed in a direction orthogonal to the angle multiplexing direction shown in FIG. 13 (perpendicular to the paper surface), the region 1401 in FIG. 14 is not belt-shaped, but is limited to a region as 1501 in FIG. It is also possible to multiplex in the direction perpendicular to the page.

In phase recording / reproduction, the phase mask 209 may not be used in order to prevent the wavefront of the oscillator light and the data page from deviating from each other. However, the signal light of the oscillator page 901 having uniform luminance and uniform phase may be used as the objective lens. When the light is condensed at 215, local energy concentration occurs, and the consumption of the recording medium becomes uneven. In order to avoid this, a phase mask 209 may be inserted in this method. This is because even if the phase of the phase mask is added, the phase is added to the oscillator page and the data page in the same manner, so that there is no influence.

Also, instead of inserting a phase mask, two pages in which 0 and 1 are inverted as shown in FIGS. 16A and 16B can be used as an oscillator page. In the case where the luminance / phase is a random or periodic pattern, since it contains a high frequency component, the energy concentration at the focal point of the objective lens 215 can be reduced. However, since phase information cannot be detected correctly in this state, two pages with at least one of luminance or phase inverted as shown in FIGS. 16A and 16B are recorded at the same location with the same reference beam angle. If this is reproduced, two pages are reproduced at the same time and interfere on the photodetector 228. However, because of the inverted pattern, the interference results in uniform brightness and phase distribution, and this interferes with the data page. By doing so, the phase information can be correctly detected as the intensity.

The above is similarly applicable to other embodiments.

This embodiment differs from the first embodiment in the reference light generation method during reproduction. In the first embodiment, the scanner optical system is arranged on the back side of the medium in order to change the data page reference light angle while fixing the oscillator reference light angle. However, the size of the optical system becomes large. Therefore, the present embodiment aims to reduce the size of the medium back surface optical system.

The data reproduction process in the present embodiment will be described in detail. FIG. 17 is a schematic diagram of the pickup 11, and FIG. 18 is an enlarged view of the periphery of the recording medium. Since the recording is the same as in the first embodiment, the description is omitted.

At the time of reproduction, the reference light whose polarization plane is inclined by 45 ° from the P-polarized light is incident on the PBS 1701 by the polarization direction conversion element 216, the reflected S-polarized component is reflected by the mirror 1702, passes through the lens 1703, is reflected by the PBS 1704, 1801 that has passed through the lens 222 irradiates the optical information recording medium 1. The light transmitted through the medium passes through the lens 223, is transmitted through the quarter-wave plate 1803, is reflected by the mirror 1804, and is transmitted through the quarter-wave plate 1803 again. , And becomes an oscillator reference beam 1806, which irradiates the optical information recording medium 1. The oscillator reference light 1806 is a traveling wave in the opposite direction of the oscillator reference light 902, and the P-polarized oscillator page reproduction light 1807 is reproduced by the diffraction of the oscillator reference light 1806 and propagates to the photodetector 228. . Note that the area of the quarter-wave plate 1803 may be larger than the area where the reference light for the oscillator is condensed as described in FIG.

On the other hand, the P-polarized light component transmitted through the PBS 1704 is reflected by the galvanometer mirror 219 set to have the same medium incident angle as that at the time of data page recording, transmitted through the lens 221 and the

PBS

1704, and 1802 transmitted through the lens 222 is light. The information recording medium 1 is irradiated. The light transmitted through the medium passes through the lens 223, is reflected by the

mirror

1804, and 1808, which is P-polarized light, passes through the lens 223 and becomes data reference light 1809 to irradiate the optical information recording medium 1. The data reference light 1809 is a traveling wave in the reverse direction of the data reference light 1002, and the reproduction light 1810 of the P-polarized data page is reproduced by the diffraction of the data reference light 1809 and propagates to the photodetector 228. .

Since the polarization state of the oscillator reference light 1806 and the data reference light 1809 are the same, the polarization state of the oscillator page reproduction light 1807 and the data page reproduction light 1810 propagated to the photodetector 228 is the same and interferes. Phase information can be detected as intensity.

According to the above circuit configuration and processing procedure, an optical information recording / reproducing apparatus capable of causing interference on the photodetector 228 without wavefront deviation between the oscillator page and the data page and capable of detecting phase information as intensity is realized. can do. In addition, since a plurality of data pages can be reproduced from one oscillator page, consumption of the recording medium by the oscillator page can be suppressed extremely small. Furthermore, by configuring the optical system using polarized light, the size of the medium back surface optical system can be reduced.

Note that the quarter wave plate 1803 is used to cause the polarization state of the reproduction light of the oscillator page and the data page to be the same and interfere with each other. If this can be realized, the configuration is limited to this configuration. Instead, the polarization state may be changed by an element using a photonic crystal.

Also, it is not limited to the polarization direction used in the description. For example, the roles of the reference light for the oscillator and the reference light for the data can be switched by replacing the galvanometer mirror 219 and the mirror 1702. In this way, if the output of the polarization direction conversion element 216 is S-polarized light during recording, the energy of the reference light is incident on the galvanometer mirror 219 without being branched, and the configuration of FIG. Similarly, it is possible to record an oscillator page and a data page.

Also, the smaller the optical path length difference between the oscillator reference beam 1806 and the data reference beam 1809, the higher the coherence and the higher quality reproduced image can be obtained. Therefore, it is possible to adjust the optical path length by a method such as inserting a phase adjusting element in one or both optical paths, or changing the arrangement of optical components such as a mirror.

The above is similarly applicable to other embodiments.

This embodiment differs from the first embodiment in an oscillator page recording method and a reference light generation method. In the first embodiment, since the reference light is branched for the oscillator and the data during reproduction, the energy utilization efficiency is poor. Therefore, the present embodiment aims to record and reproduce the oscillator page without branching the reference light.

The data recording process in this embodiment will be described in detail. FIG. 19 is a schematic view of the pickup 11, and FIG. 20 is an enlarged view around the recording medium.

At the time of recording, the galvano mirror 219 is set to the reference light incident angle for oscillator page recording, the angle of the galvano mirror 226 is set so that the light reflected by the galvano mirror 226 becomes a traveling wave in the opposite direction, and the reference light 2001 is emitted. The information recording medium 1 is irradiated. The light transmitted through the medium passes through the

lenses

223 and 224, is reflected by the galvanometer mirror 226, becomes 2002, and the oscillator reference light 2003 that passes through the

lenses

224 and 223 again irradiates the optical information recording medium 1. Interference fringes between the signal light 2004 of the oscillator page and the oscillator reference light 2003 are recorded on the optical information recording medium 1 as a hologram. The data page recording method is the same as in the first embodiment.

Next, the data reproduction process in this embodiment will be described in detail. FIG. 21 is an enlarged view around the recording medium.

During reproduction, the galvanometer mirror 219 is set to the same incident angle as that for recording the oscillator page, and the optical information recording medium 1 is irradiated with the reference light 2101 for the oscillator. Oscillator page reproduction light 2102 is reproduced by diffracting 2101 and propagates to the photodetector 228.

On the other hand, the light transmitted through the medium passes through the

lenses

223 and 224, is reflected by the galvano mirror 226 to become 2103, and the data reference light 2104 that has passed through the

lenses

224 and 223 irradiates the optical information recording medium 1. Reference numeral 2104 denotes a traveling wave in the reverse direction of the data reference light 1002, and the reproduction light 2105 of the data page is reproduced as 2104 is diffracted and propagates to the photodetector 228. Therefore, the galvanometer mirror 226 must be controlled so that 2104 has the same incident angle as that of the data reference light 1002.

Since the polarization state of the oscillator reference light 2101 and the data reference light 2104 is the same, the polarization state of the reproduction light 2102 of the oscillator page and the reproduction light 2105 of the data page propagated to the photodetector 228 are the same and interfere with each other. Phase information can be detected as intensity.

According to the above circuit configuration and processing procedure, an optical information recording / reproducing apparatus capable of causing interference on the photodetector 228 without wavefront deviation between the oscillator page and the data page and capable of detecting phase information as intensity is realized. can do. In addition, since a plurality of data pages can be reproduced from one oscillator page, consumption of the recording medium by the oscillator page can be suppressed extremely small. Furthermore, since the reference light is not branched, the energy utilization efficiency is high, and it is effective when the laser output is small.

In the case of recording an oscillator page, the description has been given of the configuration in which the oscillator reference light is incident from the back surface of the recording medium. However, the present invention is not limited to this. Conversely, when recording a data page, the data reference light is recorded. You may make it the structure which injects from a medium back surface.

The above is similarly applicable to other embodiments.

This embodiment differs from the first embodiment in the phase adjustment method of the reproduced oscillator page and data page. In the first embodiment, in some cases, the phase of the oscillator page and the data page may not match during reproduction, and phase information may not be converted into intensity information. Accordingly, an object is to adjust the phase of the reproduced oscillator page and data page.

The data recording process in this embodiment is the same as that in the first embodiment, but recording is performed by adding the phase difference detection pattern 2501 shown in FIG. 25 to a part of the data page. The phase difference detection pattern 2501 is a pattern having four types of phases as shown in the figure, and 0, π / 2, π, 3π / 2 from the reference phase plane can be used for the fringe scanning method at the time of detection. Therefore, it is convenient, but the present invention is not limited to this, and any pattern may be used as long as the reference phase can be determined.

Next, the data reproduction process in this embodiment will be described in detail. 22 is a schematic diagram of the pickup 11, FIG. 23 is an enlarged view around the recording medium, and FIG. 24 is a processing flow of data reproduction processing.

On the other hand, the light that has passed through the half mirror 227 passes through the lens 224 to become 2301, passes through the phase adjustment element 2201, is reflected by the galvano mirror 226, passes through the phase adjustment element 2201 again, becomes 2302, and the

lenses

224 and 223. The data reference beam 2303 that has passed through the optical information recording medium 1 is irradiated. Here, the phase adjustment element 2201 is assumed to be an element that can electrically control the amount of phase delay, but any element that can adjust the optical path length may be used. In addition, although the galvano mirror 226 and the phase adjustment element 2201 have been described at close positions, the present invention is not limited to this, and it may be inserted into the optical path.

The data reference light 2303 is a traveling wave in the opposite direction of the data reference light 1002, and the data reference reproduction light 2304 is diffracted to reproduce the data page reproduction light 2304 and propagate to the photodetector 228. Therefore, the galvanometer mirror 226 must be controlled so that the data reference beam 2303 has the same incident angle as the data reference beam 1002 (2401).

Here, the reproduction light of the oscillator page and the data page propagated to the photodetector 228 is caused to interfere with the photodetector 228 and the phase information is detected as intensity, but the two lights may not be in phase. . Therefore, in the phase difference detection circuit 2202 of FIG. 22, the phase difference Δφ is calculated according to (Equation 1) from the detection intensities I0 to I3 of the phase difference detection pattern 2601 of FIG. 26 detected on the photodetector 228 (2402). ).

Next, the compensation amount calculation circuit 2203 in FIG. 22 controls the phase delay amount of the phase adjustment element 2201 based on this phase difference Δφ (2403).

The subsequent processing is the same as the processing of 802 to 804 in the first embodiment.

According to the above circuit configuration and processing procedure, an optical information recording / reproducing apparatus capable of causing interference on the photodetector 228 without wavefront deviation between the oscillator page and the data page and capable of detecting phase information as intensity is realized. can do. In addition, since a plurality of data pages can be reproduced from one oscillator page, consumption of the recording medium by the oscillator page can be suppressed extremely small. Furthermore, since the phase of the reproduced oscillator page and the data page coincide with each other, the phase information can be efficiently converted into intensity information.

Note that there are a plurality of phase difference detection patterns 2501 in FIG. 25 because the phase difference Δφ is not always uniform within the page. Therefore, the phase difference Δφ is calculated from each phase difference detection pattern 2601, and each phase difference Δφ is two-dimensionally linearly interpolated to obtain the phase difference distribution in the page. Based on this, the phase adjustment element 2201 is obtained. It is also effective to two-dimensionally control the phase delay amount.

Further, the phase difference detection pattern 2501 is not limited to the pattern shown in FIG. For example, highly accurate detection is possible by increasing the types of phases, and noise tolerance can be improved by using a result obtained by enlarging the phase difference detection pattern and averaging within the same phase.

Further, although an example in which the phase adjustment element 2201 is controlled using the phase difference detection pattern 2501 has been described, control may be performed without using the phase difference detection pattern 2501. For example, the phase difference detection circuit 2202 calculates evaluation indices such as the SNR, normalized noise, and luminance of the image, and performs feedback control so that the evaluation index becomes optimal as indicated by 2701 in FIG. Changes the phase delay amount of the phase adjustment element 2201. Thereby, the phase difference detection pattern 2501 becomes unnecessary.

Also, the page used for phase difference adjustment is more advantageous for the reproduction time because it is only necessary to change the reference light angle in order in the reproduction data in the first data page. However, considering the possibility of the phase difference changing in the book, the phase difference in the book can be reduced by adjusting the data page at the angle at the center of the book.

Further, although the above phase difference adjustment method has been described with an example of performing once in a book as shown in FIG. 24, the present invention is not limited to this. Adjustments can be made on all pages, and adjustments can be made more accurately if adjustments are made once on multiple pages. Conversely, if adjustments are made once at the start of playback or on multiple books, the time required for adjustments can be shortened. It becomes possible. Further, by interpolating values adjusted for a plurality of pages or a plurality of books and applying the values to intermediate pages or books, it is possible to achieve both high accuracy of phase difference adjustment and shortening of the adjustment time.

Furthermore, the phase difference adjustment is not performed at a fixed timing, but may be performed as appropriate when the possibility that a phase difference occurs becomes high. For example, the medium may expand and contract when the temperature changes, and the influence of expansion and contraction can be suppressed by changing the reference light wavelength. However, changing the wavelength requires changing the delay amount, and it is better to perform the phase difference adjustment again.

The above is similarly applicable to other embodiments.

This embodiment differs from the fourth embodiment in the phase adjustment method of the reproduced oscillator page and data page. In the fourth embodiment, the phase adjustment element 2201 is used for the adjustment, but the cost is high. Therefore, an object is to adjust the phase without using the phase adjustment element 2201.

The data recording process in the present embodiment is the same as that in the first embodiment, but a plurality of oscillator pages having different phases are recorded as shown in FIG. FIG. 28 shows an example in which four oscillator pages are recorded. It is assumed that each oscillator page has a phase difference of 0, π / 2, π, and 3π / 2 from the reference phase plane. Although four types of oscillator pages are used here, it is preferable to record more types of phases because the adjustment resolution can be increased.

Next, the data reproduction process in this embodiment will be described in detail. FIG. 29 is a processing flow of data reproduction processing.

At the time of reproduction, the galvano mirror 219 is set to reproduce the first oscillator page (2901), and the galvano mirror 226 is set to reproduce the data page (2902). This processing is performed for all the oscillator pages (2903), the optimum oscillator page having the best evaluation index such as the SNR, the normalized noise, and the luminance of the image is determined (2904), and this optimum oscillator page is reproduced. The galvanometer mirror 219 is set (2905).

According to the above circuit configuration and processing procedure, an optical information recording / reproducing apparatus capable of causing interference on the photodetector 228 without wavefront deviation between the oscillator page and the data page and capable of detecting phase information as intensity is realized. can do. In addition, since a plurality of data pages can be reproduced from one oscillator page, consumption of the recording medium by the oscillator page can be suppressed extremely small. Furthermore, the phase of the reproduced oscillator page and the data page can be matched without using the phase adjustment element 2201.

In the description, the optimal oscillator page is determined so that the evaluation index is the best. However, as described in the fourth embodiment, the phase difference Δφ can be calculated by using the phase difference detection pattern 2501, and therefore the phase difference Δφ matches. An oscillator page having a phase difference may be set as the optimum oscillator page. Thereby, it is not necessary to perform reproduction for all the oscillator pages, and the reproduction time can be shortened.

The above is similarly applicable to other embodiments.

This embodiment is different from the first embodiment in the light amount ratio between the reproduced oscillator page and the data page. In the first embodiment, since the phase information is converted into the intensity information, it is assumed that the light quantity ratio between the reproduced oscillator page and the data page is equal. However, if the light quantity of the oscillator page is increased, the reproduced data page can be amplified and detected. Therefore, an object is to amplify the reproduced data page.

First, the principle of this embodiment will be described. 30A shows the signal point arrangement of the amplitude modulation data page (FIG. 31A), FIG. 30B shows the signal point arrangement of the phase modulation data page (FIG. 31B), and FIG. The signal point arrangement of the oscillator page (FIG. 31 (c)) is shown. The signal points are arranged so that the distance between the two signals (3001 and 3002, 3004 and 3003) is equal. “I” indicates an in-phase component of the waveform, and “Q” indicates a quadrature component, and a signal is considered on the complex plane.

When the signal in FIG. 30A is detected by the photodetector 228, the square of the complex signal is detected, so that the signal 3002 has the intensity I1 from (Equation 2) and the signal 3001 has the intensity from (Equation 3). I0, and the inter-signal distance ΔIa is (Expression 4).

Next, assuming that the data page of FIG. 30B is converted into intensity by the oscillator page of FIG. 30C and detected by the photodetector 228, the square of the complex signal is detected. The signal 3004 becomes the intensity I1 from (Equation 5), the signal 3003 becomes the intensity I0 from (Equation 6), and the inter-signal distance ΔIb becomes (Equation 7). It is assumed that the data page signal 3004 and the oscillator page are in phase.

From the above, even if the original inter-signal distance is the same, if the phase-modulated data page is reproduced on the oscillator page, the amplification factor α shown in (Equation 8) can be obtained. As shown by this equation, if the light quantity of the oscillator page is larger than the light quantity of the data page, the data page can be amplified with the amplification factor α.

There are two main ways to achieve this. One is a method for increasing the diffraction efficiency of the hologram of the oscillator page, and the other is a method for increasing the amount of the reference light for the oscillator to be irradiated. Of course, these methods may be used in combination.

First, a method for increasing the diffraction efficiency of the hologram on the oscillator page will be described.

For example, in the oscillator page recording process (702) of the first embodiment, a hologram having high diffraction efficiency is formed by increasing the exposure time, which is the time for irradiating the recording medium with light, compared to the data page recording process (704). Can be realized. Further, in the oscillator page recording process (702), it can be realized by increasing the light amount of at least one signal light of the oscillator reference light or the oscillator page.

According to these methods, even when the oscillator reference light having the same light amount as the data reference light is irradiated, the light diffracted from the hologram is larger on the oscillator page than on the data page. Further, although the consumption amount of the recording medium increases, the influence is small because the ratio of the oscillator page to the whole page is still small as described above.

Next, a method for increasing the amount of the reference light for the oscillator to be irradiated will be described.

For example, in the first embodiment, this can be realized by making the transmittance of the half mirror portion of the half mirror 227 of FIG. 11 smaller than 50%. Further, in the second embodiment, it can be realized by adjusting the polarization direction conversion element 216 in FIG. 17 and using the reference light whose polarization plane is inclined from 45 ° to 90 ° from the P-polarized light. In Example 3, this can be realized by reducing the reflectance of the galvanometer mirror 226.

According to these methods, even if an oscillator page having the same diffraction efficiency as that of the data page is recorded, the light diffracted from the hologram is more diffracted from the hologram page than the data page because the amount of reference light for the oscillator to be irradiated is large Becomes larger. It is also possible to suppress an increase in the consumption of the recording medium.

In addition, this invention is not limited to said Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, 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. As modifications, the following configurations can be cited.

As a first modification, in an optical information recording apparatus that records information on an optical information recording medium using holography, a light source that generates reference light, signal light, and oscillator light, and information is added to the signal light generated by the light source A signal light modulating unit that irradiates the optical information recording medium with the signal light modulated by the signal light modulating unit, and an oscillator that irradiates the optical information recording medium with the oscillator light generated by the light source A light irradiation unit; and a reference light irradiation unit that irradiates the optical information recording medium with the reference light generated by the light source. The signal light emitted from the signal light irradiation unit, and the reference light irradiation unit Oscillator light emitted from the oscillator light irradiating unit, which records multiple interference fringes with the irradiated reference light as signal light holograms in a predetermined area of the optical information recording medium, and the reference light irradiating unit Recording the interference fringe between et irradiated reference light as the oscillator hologram, it is an optical information recording apparatus according to claim.

As a second modification, in the optical information recording apparatus described in the first modification, when multiple information is recorded, the angle at which the reference light irradiated from the reference light irradiation unit is incident on the optical information recording medium is changed. There is an optical information recording apparatus characterized by recording while changing.

As a third modification, in the optical information recording apparatus according to the first modification, a phase difference adjustment pattern is embedded in a part of the signal light modulated by the signal light modulation unit. There is a recording device.

As a fourth modification, in the optical information recording apparatus according to the first modification, a plurality of oscillator lights having different phases are multiplexed and recorded in the predetermined area of the optical information recording medium as the oscillator optical hologram. There is an optical information recording apparatus.

Modified example 5 is an optical information recording apparatus according to modified example 1, wherein the signal light hologram and the oscillator hologram are recorded with different diffraction efficiencies.

As a sixth modification, in an optical information reproducing apparatus that reproduces information recorded on an optical information recording medium using holography, a light source that generates reference light and oscillator light, and an oscillator light generated by the light source An oscillator light irradiating unit for irradiating the information recording medium, a reference light irradiating unit for irradiating the optical information recording medium with reference light generated by the light source, and a light detecting unit for detecting light reproduced from the optical information recording medium The optical information recording medium includes an interference fringe between the signal light modulated with information added and the reference light emitted from the reference light irradiation unit as a signal light hologram. Interference fringes between the oscillator light irradiated from the oscillator light irradiating unit and the reference light irradiated from the reference light irradiating unit are recorded as an oscillator hologram. From the reference light that is recorded and reproduced from the signal light hologram by the reference light for signal light generated from the reference light emitted from the reference light irradiation unit, and from the reference light emitted from the reference light irradiation unit An optical information reproducing apparatus, wherein the oscillator light is reproduced from the oscillator hologram by the generated oscillator light reference light, and the reproduced signal light and the oscillator light are detected by the light detection unit.

As a modification example 7, in the optical information reproducing apparatus according to the modification example 6, the signal light reference light and the oscillator light reference light are generated by branching the reference light emitted from the reference light irradiation unit. There is an optical information reproducing apparatus characterized in that.

As a modified example 8, in the optical information reproducing apparatus according to the modified example 6, the reference light for signal light and the reference light for oscillator light branch off the reference light emitted from the reference light irradiating unit and branch the reference There is an optical information reproducing apparatus characterized in that the polarization of light is orthogonal.

As Modification 9, in the optical information reproducing apparatus according to Modification 6, the reference light for oscillator light is generated from the reference light emitted from the reference light irradiation unit, and the reference light for signal light is the reference The reference light emitted from the light irradiation unit is generated from the light transmitted through the optical information recording medium,
There is an optical information reproducing apparatus characterized in that.

As a tenth modification, the optical information reproducing apparatus according to the sixth modification includes a phase adjusting element that adjusts a phase difference between the reference light for signal light and the reference light for oscillator light, and is based on the output of the light detection unit. There is an optical information recording / reproducing apparatus for controlling the phase adjusting element.

As an eleventh modification, there is an optical information reproducing apparatus according to the sixth modification, wherein the optical information recording / reproducing apparatus reproduces the signal light by changing the light amount of the reference light and the reference light for the oscillator light. .

As a modified example 12, in an optical information recording method for recording information on an optical information recording medium using holography, a light generation step for generating reference light, signal light and oscillator light, and information on the signal light generated by the light source A signal light modulation step of adding, a signal light irradiation step of irradiating the optical information recording medium with the signal light modulated in the signal light modulation step, and irradiating the optical information recording medium with the oscillator light generated by the light source An oscillator light irradiating step, and a reference light irradiating step for irradiating the optical information recording medium with the reference light generated by the light source, the signal light irradiated in the signal light irradiating step, and the reference light irradiating The interference fringes with the reference light irradiated in the step are multiplexed and recorded as a signal light hologram on a predetermined area of the optical information recording medium, and the oscillator light irradiation is performed. An oscillator light emitted in step, recording the interference fringes between the irradiated reference light from said reference light irradiating step as oscillator holograms, there are optical information recording method characterized by.

As a modified example 13, in the optical information recording method described in the modified example 12, when information is multiplexed and recorded, the angle at which the reference light irradiated in the reference light irradiation step is incident on the optical information recording medium is changed. There is an optical information recording / reproducing method characterized by recording while changing.

As a modified example 14, in the optical information recording / reproducing method according to the modified example 12, a phase difference adjustment pattern is embedded in one step of the signal light modulated in the signal light modulation step. There is an information recording method.

As a modified example 15, in the optical information recording method described in the modified example 12, a plurality of oscillator lights having different phases are multiplexed and recorded in the predetermined area of the optical information recording medium as the oscillator optical hologram. There is an optical information recording method.

Modified example 16 is an optical information recording method according to modified example 12, characterized in that recording is performed by changing diffraction efficiency of the signal light hologram and the oscillator hologram.

As a modified example 17, in an optical information reproducing method for reproducing information from an optical information recording medium on which information is recorded using holography, a light generating step for generating reference light and oscillator light, and an oscillator generated by the light source An oscillator light irradiating step for irradiating the optical information recording medium with light, a reference light irradiating step for irradiating the optical information recording medium with reference light generated by the light source, and detecting light reproduced from the optical information recording medium The optical information recording medium includes a predetermined region of the optical information recording medium in which interference fringes between the signal light to which information is added and modulated and the reference light are signal light holograms. The interference fringes between the oscillator light and the reference light are recorded as an oscillator hologram and irradiated in the reference light irradiation step. The signal light is reproduced from the signal light hologram by the signal light reference light generated from the generated reference light, and the oscillator light reference light generated from the reference light irradiated in the reference light irradiation step is used to generate the oscillator light. There is an optical information reproducing method characterized in that oscillator light is reproduced from a hologram, and the reproduced signal light and oscillator light are detected in the light detection step.

As a modified example 18, in the optical information reproducing method according to the modified example 17, the reference light for signal light and the reference light for oscillator light are generated by branching the reference light irradiated in the reference light irradiation step. There is an optical information reproducing method characterized by this.

As a modified example 19, in the optical information reproducing method according to the modified example 17, the reference light for signal light and the reference light for oscillator light branch off the reference light irradiated in the reference light irradiation step and branch the reference There is an optical information recording / reproducing method characterized in that the polarization of light is orthogonal.

As a modification 20, in the optical information reproducing method according to the modification 17, the reference light for oscillator light is generated from the reference light emitted from the reference light irradiation step, and the reference light for signal light is the reference There is an optical information recording / reproducing method characterized in that the reference light emitted from the light irradiation step is generated from the light transmitted through the optical information recording medium.

As a modified example 21, in the optical information reproducing method according to the modified example 17, the optical information reproducing method includes a phase adjusting element that adjusts a phase difference between the reference light for signal light and the reference light for oscillator light, and is based on the output of the light detection step. There is an optical information reproduction method characterized by controlling the phase adjusting element.

As a modified example 22, there is an optical information reproducing method according to the modified example 17, wherein the signal light reference light and the oscillator light reference light are reproduced with different amounts of light.

Further, the optical information recording medium is not limited to a recording medium using holography, and may be a DVD (Digital Versatile Disc) or a BD (Blu-ray Disc (registered trademark)), for example.

In addition, each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files that realize each function can be stored in a memory, a hard disk, a recording device such as an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

Also, the control lines and information lines indicate what is considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

DESCRIPTION OF SYMBOLS 1 ... Optical information recording medium, 10 ... Optical information recording / reproducing apparatus, 11 ... Pickup, 12 ... Reference optical system for reproduction | regeneration, 13 ... Disc Cure optical system, 14 ... Disc Rotation angle detection optical system, 15 ... position detection optical system, 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 ... Disk rotation motor control circuit 89 ... Controller 90 ... Input / output control circuit, 91 ... external control device, 201 ... light source, 202 ... collimating lens, 203 ... shutter, 204 ... 1/2 wavelength plate, 205 ... polarizing beam splitter, 206 ... Signal light, 207... Reference light, 208... Beam expander, 209... Phase (phase) mask, 210 ... Relay lens, 211 ... Polarization beam splitter, 212 ... Spatial light modulator 213 ... Relay lens, 214 ... Spatial filter, 215 ... Objective lens, 216 ... Polarization direction conversion element, 217 ... Mirror, 218 ... Mirror, 219 ... Mirror, 220 ... Actuator, 221 ... Lens, 222 ... Lens, 223 ... Lens, 224 ... Lens, 225 ... Actuator, 226 ... Mirror, 227 ... Half mirror, 228 ..Photodetector, 1401... Half mirror region, 1402... Transmission region, 1501... Half mirror region, 1803. 1804: mirror, 2201 ... phase adjustment element, 2202 ... phase difference detection circuit, 2203 ... compensation amount calculation circuit, 2501 ... phase difference detection pattern (recording), 2601 ... phase difference Detection pattern (playback),

Claims

In an optical information recording apparatus that records information on an optical information recording medium using holography,
A light source for generating reference light, signal light and oscillator light;
A signal light modulator for adding information to the signal light generated by the light source;
A signal light irradiation unit that irradiates the optical information recording medium with the signal light modulated by the signal light modulation unit;
An oscillator light irradiation unit for irradiating the optical information recording medium with the oscillator light generated by the light source;
A reference light irradiation unit that irradiates the optical information recording medium with the reference light generated by the light source;
Comprising
As a signal light hologram, interference fringes between the signal light irradiated from the signal light irradiation unit and the reference light irradiated from the reference light irradiation unit are multiplexed and recorded in a predetermined area of the optical information recording medium,
Recording interference fringes between the oscillator light irradiated from the oscillator light irradiation unit and the reference light irradiated from the reference light irradiation unit as an oscillator hologram,
An optical information recording apparatus.
The optical information recording apparatus according to claim 1,
When multiplex recording information, recording while changing the angle at which the reference light irradiated from the reference light irradiation unit is incident on the optical information recording medium,
An optical information recording apparatus.
The optical information recording apparatus according to claim 1,
A phase difference adjustment pattern is embedded in part of the signal light modulated by the signal light modulation unit,
An optical information recording apparatus.
The optical information recording apparatus according to claim 1,
A plurality of oscillator lights having different phases are multiplexed and recorded in the predetermined area of the optical information recording medium as the oscillator optical hologram.
An optical information recording apparatus.
The optical information recording apparatus according to claim 1,
Recording the signal light hologram and the oscillator hologram with different diffraction efficiencies,
An optical information recording apparatus.
In an optical information reproducing apparatus for reproducing information recorded on an optical information recording medium using holography,
A light source for generating reference light and oscillator light;
An oscillator light irradiation unit for irradiating the optical information recording medium with the oscillator light generated by the light source;
A reference light irradiation unit that irradiates the optical information recording medium with the reference light generated by the light source;
A light detection unit for detecting light reproduced from the optical information recording medium;
Comprising
In the optical information recording medium, interference fringes between signal light modulated with information added and reference light emitted from the reference light irradiating unit are multiplexed as a signal light hologram on a predetermined region of the optical information recording medium. Interference fringes between the recorded oscillator light emitted from the oscillator light irradiation unit and the reference light emitted from the reference light irradiation unit are recorded as an oscillator hologram,
The signal light is reproduced from the signal light hologram by the reference light for signal light generated from the reference light emitted from the reference light irradiation unit,
With the reference light for oscillator light generated from the reference light emitted from the reference light irradiation unit, the oscillator light is reproduced from the oscillator hologram,
The reproduced signal light and oscillator light are detected by the light detection unit,
An optical information reproducing apparatus characterized by the above.
The optical information reproducing apparatus according to claim 6,
The signal light reference light and the oscillator light reference light are generated by branching the reference light emitted from the reference light irradiation unit,
An optical information reproducing apparatus characterized by the above.
The optical information reproducing apparatus according to claim 6,
The reference light for signal light and the reference light for oscillator light branch off the reference light emitted from the reference light irradiation unit, and the polarization of the branched reference light is orthogonal,
An optical information reproducing apparatus characterized by the above.
The optical information reproducing apparatus according to claim 6,
The reference light for oscillator light is generated from the reference light irradiated from the reference light irradiation unit,
The signal light reference light is generated from light transmitted from the optical information recording medium by the reference light irradiated from the reference light irradiation unit.
An optical information reproducing apparatus characterized by the above.
The optical information reproducing apparatus according to claim 6,
A phase adjusting element for adjusting a phase difference between the signal light reference light and the oscillator light reference light;
Controlling the phase adjustment element based on the light detection unit output;
An optical information reproducing apparatus characterized by the above.
The optical information reproducing apparatus according to claim 6,
Reproducing by changing the amount of the reference light for signal light and the reference light for oscillator light,
An optical information reproducing apparatus characterized by the above.