JP5320343B2 - Optical information recording / reproducing apparatus and optical information recording / reproducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology and an optical information recording/reproducing device, capable of quickly retrieving desired retrieval information and information similar to this retrieval information from an angle multiple hologram which records a plurality of pieces of data with overlapping on the same place by changing an incident angle of reference light to an optical information recording medium. <P>SOLUTION: In a retrieval processing at the optical information recording/reproducing device which reproduces the optical information recording medium recorded by the angle multiplex, the optical information recording medium is irradiated from a route of a signal light with light added with the desired retrieval information, and an existence of the information similar to the retrieval information in the multiplex recorded information is judged by using a light quantity of diffraction light to be reproduced, and when the similar information is existent, the incident angle of the reference light optimum for reproducing the similarity and similar information is searched by using the light quantity and an emission angle of the diffraction light. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

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

  In recent years, Blu-ray Disc (BD) using a blue-violet semiconductor laser has made it possible to record and reproduce about 50 GB on an optical disc even for consumer use.

  In the future, even for optical discs, it will be necessary to increase the capacity of 100 GB to 1 TB to the same level as the HDD (Hard Disc Drive) capacity.

  However, in order to realize such an ultra-high density with an optical disk, a new storage technology different from the trend of the conventional high-density technology due to the shorter wavelength and the higher objective lens NA is required. .

  While research on next-generation storage technology is being conducted, there is a hologram recording technology that records digital information using holography.

  As a hologram recording technique, for example, there is JP-A-2004-272268 (Patent Document 1). In this publication, a signal beam is condensed on an optical information recording medium by a lens, and simultaneously, a hologram is recorded by irradiating and collimating a reference beam of a parallel beam, and further determining the incident angle of the reference beam on the optical recording medium. A so-called angle multiplex recording method is described in which multiplex recording is performed by displaying different page data on a spatial light modulator while changing. Furthermore, in this publication, the distance between adjacent holograms can be shortened by condensing the signal light with a lens and providing an aperture (spatial filter) in the beam waist, which is compared with the conventional angle multiplex recording system. A technique for increasing the recording density / capacity is described.

  Further, as a hologram recording technique, for example, there is WO2004-102542 (Patent Document 2). 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.

  As a search method for hologram recording information, for example, there is JP-A-2009-216759 (Patent Document 3). According to this publication, “hologram recording layer 21 of holographic recording medium 20 is recorded with hologram 24 formed by interference of reference light and information light spatially modulated by two-dimensional pattern information for recording. The light emitted from the CW laser 54 is spatially modulated by the two-dimensional pattern information for search to generate search light, the search light is irradiated to the hologram recorded in the hologram recording layer, and the recording medium The reproduction light detector 59 detects the light intensity of the reproduction light reproduced from the hologram, and collates the two-dimensional pattern information for recording with the two-dimensional pattern information for search using the value of the light intensity of the reproduction light. Is described.

JP 2004-272268 A WO2004-102542 JP 2009-216759 A

  By the way, even in an optical information recording / reproducing apparatus using angle-multiplexed recording holography in which the incident angle of the reference light to the optical information recording medium is changed and a plurality of data is recorded in the same place, the retrieval of recorded information is performed at high speed. It is desirable to be able to do it.

  However, a technology relating to an optical information recording / reproducing device that satisfies the above requirements and a technology relating to the device configuration have not been disclosed.

  An object of the present invention is to retrieve desired recording information from a hologram recorded by angle multiplexing at high speed.

  An object of the present invention is to irradiate the optical information recording medium with light to which desired search information is added and retrieve information from the reproduced diffracted light in a search process from an optical information recording medium recorded by angle multiplexing as an example. This can be achieved by searching.

  According to the present invention, desired recording information can be retrieved at high speed from a hologram recorded by angle multiplexing.

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 A flowchart showing an example of an operation flow of the optical information recording / reproducing apparatus. Schematic showing an embodiment of a pickup when searching for information in an optical information recording / reproducing apparatus Schematic showing an embodiment of a pickup when searching for information in an optical information recording / reproducing apparatus Schematic showing an embodiment of a pickup when searching for information in an optical information recording / reproducing apparatus Schematic showing an embodiment of a pickup when searching for information in an optical information recording / reproducing apparatus Schematic showing an embodiment of a pickup when searching for information in an optical information recording / reproducing apparatus Schematic showing an embodiment of a pickup when searching for information in an optical information recording / reproducing apparatus Flowchart representing an embodiment of information search flow of optical information recording / reproducing apparatus Schematic showing an embodiment of recording / reproducing and information retrieval of an optical information recording / reproducing apparatus Schematic showing an embodiment of information retrieval of an optical information recording / reproducing apparatus Schematic showing an example of information search results of an optical information recording / reproducing apparatus Schematic showing the relationship between the angle of diffracted light and the detection position during information retrieval by an optical information recording / reproducing apparatus Flowchart representing an embodiment of information search flow of optical information recording / reproducing apparatus Schematic showing an example of information search results of an optical information recording / reproducing apparatus

  Examples of the present invention will be described below.

  Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a recording / reproducing apparatus of an optical information recording medium for recording and / or reproducing digital information using holography.

  The optical information recording / reproducing apparatus 10 includes a pickup 11, a phase conjugate optical system 12, a disk cure optical system 13, a disk rotation angle detection optical system 14, and a rotation motor 50, and the optical information recording medium 1 is a rotation motor 50. It is the structure which can be rotated by.

  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 in the optical information recording medium 1, the phase conjugate light of the reference light emitted from the pickup 11 is generated by the phase conjugate optical system 12. Here, the phase conjugate light is a light wave that travels in the opposite direction while maintaining the same wavefront as the input light. Reproduction light reproduced by the phase conjugate light is detected by a photodetector 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 disk 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 disk 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 quantity. be able to.

Further, the pickup 11 and the disk 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 position control is performed via the access control circuit 81.
By the way, the recording technique using the principle of angle multiplexing of holography tends to have a very small tolerance for the deviation of the reference beam angle.

  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. A servo mechanism for this purpose may be provided in the optical information recording / reproducing apparatus 10.

  The pickup 11, the disk 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.

  FIG. 2 shows an example of a basic optical system configuration of the pickup 11 in the optical information recording / reproducing apparatus 10. The light beam emitted from the light source 201 passes through the collimator lens 202 and enters the shutter 203. When the shutter 203 is open, after the light beam passes through the shutter 203, the optical element 204 composed of, for example, a half-wave plate or the like, adjusts the light quantity ratio of p-polarized light and s-polarized light to a desired ratio. After the polarization direction is controlled, the light beam enters a PBS (Polarization Beam Splitter) prism 205.

  The light beam that has passed through the PBS prism 205 functions as signal light 206, the light beam diameter is enlarged by the beam expander 208, and then passes through the PBS prism 209 and enters the spatial light modulator 210.

  The signal light to which information is added by the spatial light modulator 210 is reflected by the PBS prism 209 and propagates through the relay lens 211 and the spatial filter 212. Thereafter, the signal light is condensed on the optical information recording medium 1 by the objective lens 213. The spatial modulator 210 may be configured to incorporate a phase mask function.

  On the other hand, the light beam reflected from the PBS prism 205 acts as reference light 207, which is set to a predetermined polarization direction according to recording or reproduction by the polarization direction conversion element 214, and then galvanically passed through the mirror 215 and the mirror 216. Incident on the mirror 217. Since the angle of the galvanometer mirror 217 can be adjusted by the actuator 218, the incident angle of the reference light incident on the optical information recording medium 1 after passing through the lens 219 and the lens 220 can be set to a desired angle.

  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. In addition, since the incident angle of the reference light incident on the optical information recording medium 1 can be changed by the galvanometer mirror 217, recording by angle multiplexing is possible. In the future, in holograms recorded with different reference beam angles in the same area, each hologram corresponding to one reference beam angle will be called a page, and a group of pages angle-multiplexed in the same area will be called a book. To.

  FIG. 3 shows the optical path particularly related to reproduction in the optical system of FIG. 2 by a solid line, and shows the optical path not related to reproduction by a dotted line. When reproducing the recorded information, for example, the polarization direction is controlled by the optical element 204 so that the amount of s-polarized light is maximized, and the light beam of the s-polarization method is reflected by the PBS prism 205 to obtain the reference light 207 for reproduction. To do. Thereafter, the polarization direction conversion element 214 converts the polarization direction of the reference light 207 into p-polarized light, and the reference light 207 is incident on the optical information recording medium 1 and transmitted through the optical information recording medium 1 in the same manner as in the recording described above. The phase conjugate light is generated by reflecting the beam by the galvano mirror 222 whose angle can be adjusted by the actuator 221.

  The signal light reproduced by the phase conjugate light propagates through the objective lens 213, the relay lens 211, and the spatial filter 212. Thereafter, the signal light passes through the PBS prism 209 and enters the photodetector 223, and the recorded signal can be reproduced.

  The optical system configuration of the pickup 11 is not limited to FIG. 2 or FIG.

  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 (S301), the optical information recording / reproducing apparatus 10 discriminates whether or not the inserted medium is a medium for recording or reproducing digital information using holography, for example. (S302).

  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, for example, Information relating to the optical information recording medium and information relating to various setting conditions during recording and reproduction, for example, are acquired (S303).

  After reading out the control data, various adjustments according to the control data and learning processing related to the pickup 11 are performed (S304), and the optical information recording / reproducing apparatus 10 is ready for recording or reproduction (S305).

  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, and information corresponding to the data is sent to the spatial light modulator in the pickup 11 ( S306).

  After that, various learning processes are performed in advance as necessary so that high-quality information can be recorded on the optical information recording medium (S307), and the pickup 11 and the disc are repeated while repeating the seek operation (S308) and the address reproduction (S309). The position of the cure optical system 13 is arranged at a predetermined position on the optical information recording medium.

  Thereafter, a predetermined area is pre-cured using a light beam emitted from the disk cure optical system 13 (S310), and data is recorded using reference light and signal light emitted from the pickup 11 (S311).

  After the data is recorded, the data is verified as necessary (S312), and post-cure is performed using the light beam emitted from the disk Cure optical system 13 (S313).

  As shown in FIG. 4C, the operation flow from the ready state to the reproduction of the recorded information is performed in advance with various learning processes as necessary so that high-quality information can be reproduced from the optical information recording medium. (S314). Thereafter, the positions of the pickup 11 and the phase conjugate optical system 12 are arranged at predetermined positions on the optical information recording medium while repeating the seek operation (S315) and the address reproduction (S316).

  Thereafter, reference light is emitted from the pickup 11 and information recorded on the optical information recording medium is read (S317).

  In the description of the following embodiments, the description of the components common to the basic optical system of FIGS. 2 and 3 is omitted.

  FIG. 5 shows an example of the first embodiment of the optical system configuration of the pickup 11 in the optical information recording / reproducing apparatus 10. In the embodiment shown in FIG. 5, in addition to the basic optical system configuration shown in FIG. 2, the reference light diffracted from the optical information recording medium 1 is reflected by the galvanometer mirror 222 and then incident on the lens 230 to obtain a photodetector. In this configuration, the light is condensed at 231.

  When searching for desired information, a part or all of the pixels of the spatial light modulator 210 are made into a two-dimensional pattern of ON and OFF corresponding to the desired information, and the light beam is moved from the optical path of the signal light to the optical information recording medium 1. The diffracted light is regenerated by irradiating. Hereinafter, the light beam for search is referred to as search light. The reproduced diffracted light is reflected by the galvanometer mirror 222, enters the lens 230, and is condensed on the photodetector 231.

  The reason why information search is possible by irradiation of search light with desired search information added will be described. As described above, when information is recorded on an optical information recording medium using holography, the information is recorded by changing the incident angle of the reference light according to the recording information as shown in FIGS. 12 (a1) to (a3). The added signal light is caused to interfere in the optical information recording medium, and the interference fringes are recorded on the optical information recording medium. When reproducing, the reference light having the same amplitude distribution and phase distribution as that recorded on the optical information recording medium on which information is recorded as shown in FIGS. 12 (b1) to (b3) is applied to the optical information recording medium. The signal light can be diffracted and reproduced by irradiating it as phase conjugate light at the same incident angle as when recording. On the other hand, as shown in FIGS. 12C1 to 12C3, when the optical information recording medium is irradiated with a light beam having the same amplitude distribution and phase distribution as the signal light at the time of recording, the reference light at the time of recording is recorded. Diffracted light having the same amplitude distribution and phase distribution can be diffracted at substantially the same angle as the reference light when recording. In this embodiment, a method and apparatus for searching for desired information using this phenomenon is proposed. That is, by adding desired search information to the search light using a spatial light modulator and irradiating the search light to the optical information recording medium, when similar information to the search information is recorded, Diffracted light similar to the reference light when similar information is recorded can be obtained. In FIG. 12, the relay lens 211 and the spatial filter 212 are omitted.

  For example, assuming the optical system shown in FIG. 13A, the search light is optical information as a pattern similar to that when recording desired information for searching the ON and OFF two-dimensional patterns of the spatial light modulator 210. When incident on the recording medium 1, the same light as the reference light at the time of recording by angle multiplexing at the same location of the optical information recording medium 1 is simultaneously diffracted with a light quantity corresponding to the similarity to the search information. As shown in FIG. 13B, the reproduced diffracted light is condensed on the photodetector 231 at a position corresponding to the angle by the lens 230, so that the position and light amount of each bright spot collected on the photodetector. By detecting this, it is possible to determine the presence or absence of similar information with the search information, and when there is similar information, it is possible to obtain the incident angle information of the reference light at the time of recording. Also, the higher the similarity between the light quantity distribution of the signal light during recording and the light quantity distribution of the search light during search, the stronger the diffracted light quantity reproduced during information retrieval. By detecting it, it is possible to obtain information on the degree of similarity between the search information and the searched similar information. In FIG. 13, the relay lens 211 and the spatial filter 212 are omitted.

  FIG. 14 shows an example of the relationship between the position x of the bright spot condensed on the photodetector and the amount of light I detected by the photodetector during information retrieval. The similarity between the search information and the information recorded on the optical recording medium 1 as a hologram is detected as the reproduction light quantity I. At this time, a reference value for an arbitrary reproduction light quantity is provided, and information having a light quantity larger than the reference value is similar information, and information having a light quantity smaller than the reference value is determined not to be similar information. The presence or absence of similar information in the hologram can be checked. For information exceeding the reference value, it is possible to obtain the position at which the reproduction light amount is maximum, and to calculate the optimum reference light incident angle for reproducing similar information from this position information.

  Here, an example of a method for obtaining the reference light angle at the time of recording from the position of the bright spot focused on the photodetector will be described. As shown in FIG. 15, a lens 230 is disposed at a focal distance f of the lens 230 from the hologram in the optical information recording medium 1 to be searched, and a photodetector 231 is parallel to the lens 230 at the position f. Arrange so that When the center position of the photodetector 231 is aligned with the axis of the lens 230 and the angle of diffracted light from the axis is φ, the position x of the bright spot on the photodetector is expressed by, for example, Expression (1). In FIG. 15, reflection at the galvanometer mirror 222 is omitted.

x = fsinφ (1)
Further, the relationship between the angle θ of the diffracted light and the angle φ of the diffracted light and the above φ is such that the angle formed by the surface perpendicular to the optical axis of the lens 230 and the surface perpendicular to the rotational axis of the optical information recording medium 1 is ψ. For example, it is represented by Formula (2).
θ = φ + ψ (2)

  Accordingly, by detecting the position x of the bright spot by the photodetector 231, angle information of the reproduced diffracted light can be obtained, and an optimum reference light angle for reproduction can be calculated from this information. Similarly, information on the angle in the direction orthogonal to the multiplex direction can also be obtained by detecting the position of the bright spot in the y direction, where y is the direction orthogonal to x on the detection surface of the photodetector 231. it can.

  By performing the above-described reproduction operation after controlling the galvanometer mirror 217 and the galvanometer mirror 222 to a desired angle based on the angle information and the similarity obtained in this way, the search information is obtained with the optimum reference beam angle. Similar information can be reproduced. When information is recorded using a phase mask at the time of recording, the diffracted light is detected when the phase information of the light beam applied to the optical information recording medium 1 matches the phase information of the signal light at the time of recording. Is reproduced, it is necessary to match part or all of the phase of the signal light during recording.

  When reproducing similar information, the angles of the galvano mirror 217 and the galvano mirror 222 may be set so as to be the reference light angle obtained by the main search as described above, or the reference light angle obtained by the main search is set to the reference light angle. The closest reference light angle at the time of recording may be calculated, and the angles of the galvano mirror 217 and the galvano mirror 222 may be set so as to be the reference light angle at the time of recording. Further, the calculated angle may be compared with an angle table at the time of recording, and the page number corresponding to the closest angle may be held as a search result.

  Here, the light detector 231 may be a light detector capable of detecting light information two-dimensionally as represented by a CMOS image sensor, or one-dimensionally detecting light information such as a line sensor. Possible photodetectors may be used. The advantage of using a photodetector capable of detecting light information two-dimensionally is that not only the angle information in the direction of angle multiplexing but also the angle information orthogonal thereto can be obtained for the optimum angle of the reference light. is there. The pixel size of the photodetector 231 may be a pixel size corresponding to the angular resolution necessary for optimally controlling the angle of the reference light, or the position information and luminance information of each pixel of the photodetector 231 are used. If the necessary angular resolution can be obtained by calculating the centroid of the bright spot, the pixel size may be larger. Also, if necessary, the resolution of angle information detection may be increased by increasing the focal length of the lens 230 to form an enlargement system.

  An example of an operation for searching for desired information is shown in FIG. In step 401, the disc rotation motor control circuit 88 and the access control circuit 81 are controlled so that the book to be reproduced faces the objective lens, and the disc is positioned. In step 402, the actuator 221 is controlled so that the angle of the galvanometer mirror 222 becomes an angle suitable for information retrieval. In step 403, the diffracted light reproduced by irradiating the optical information recording medium 1 on which the information is recorded with the search light to which the desired search information is added is detected by the photodetector 231 and the amount of the diffracted light is detected. Determine the presence or absence of similar information. In step 404, the process branches depending on the presence / absence of similar information, and if there is no similar information, the process proceeds to a search for another book in step 405. If there is similar information, the light quantity and angle of diffracted light are determined in step 406. Get similarity and playback conditions from After obtaining the similarity and the reproduction condition, the similarity information to be reproduced is determined from the similarity in step 407, and the galvanometer mirror 217 and the optimum reference beam angle for reproducing the similarity information determined in step 408 are obtained. The angle of the galvanometer mirror 222 is set. In step 409, the hologram recorded in the optical information recording medium 1 is irradiated with reference light to reproduce similar information. In step 410, it is determined whether or not other similar information is to be reproduced. If other similar information is to be reproduced, the process returns to step 407. If reproduction of other similar information is not to be continued, step 405 is performed to reproduce another similar information. Proceed to determine whether to search. If it is determined in step 405 that another book is to be searched, the process returns to step 401. If no other book is to be searched, the search process is terminated.

  In consideration of the compatibility of the optical information recording / reproducing apparatus or the optical information recording medium, when the optical information recording medium 1 is irradiated with the light beam in order to detect the optimum reference light angle, the optical beam and the optical information recording medium 1 are used. When it is necessary to match the relative positional relationship and the angular relationship with the optical information recording / reproducing apparatus 10 or the pickup 11, the optical information recording medium 1 or the pickup 11 is provided with a mechanism capable of adjusting the position and angle of the optical information recording medium 1 or the pickup 11. It doesn't matter.

  FIG. 6 shows a first modification of the first embodiment of the optical system configuration of the pickup 11 in the optical information recording / reproducing apparatus 10. In FIG. 6, instead of the mirror 222 in the optical system configuration of FIG. 5, a transmission / reflection variable element 232 capable of electrically changing the transmission / reflection state of light is arranged, and the lens 230 and the photodetector 231 are mirrors. The configuration is arranged behind 232. At the time of reproduction, the transmission / reflection variable element 232 functions as a reflecting plate, and the reference light transmitted through the optical information recording medium 1 is reflected by the transmission / reflection variable element 232 and recorded again on the optical information recording medium 1 as phase conjugate light. The signal light is reproduced by entering the hologram. The transmissive / reflective variable element 232 is, for example, a transparent state depending on the voltage application direction described in K. Tajima et al .: Electrochem. Solid-State Lett., Volume 10, Issue 3, pp. J52-J54 (2007). A light control mirror film capable of switching the mirror state can be used.

  When searching for information, the spatial light modulator 210 is used to add desired search information to the search light and irradiate the optical information recording medium 1 with the search light to reproduce the diffracted light. At this time, the transmission / reflection variable element 232 functions as a transmission plate, and the reproduced diffracted light passes through the transmission / reflection variable element 232, enters the lens 230, and is condensed on the photodetector 231. The reason why the optimal reference light angle can be detected by the light detector 231 and the arrangement configuration of the light detector 231 are the same as those in the first embodiment, and a description thereof will be omitted.

  The transmission / reflection variable element 232 may be configured to electrically change the state of light transmission / reflection as described above, or may be a mirror that can transmit part of the light.

  In this modification, there is an advantage that it is possible to shorten the process and time required for the preparation for the search because it is not necessary to adjust the angle of the galvanometer mirror when searching for information.

  FIG. 7 shows a second modification of the first embodiment of the optical system configuration of the pickup 11 in the optical information recording / reproducing apparatus 10. In FIG. 7, a lens 233, a transmission / reflection variable element 232, and a photodetector 231 are arranged instead of the galvanometer mirror 222 and the actuator 221 in the optical system configuration of FIG. At the time of reproduction, the reference light transmitted through the optical information recording medium 1 enters the lens 233 and is condensed on the transmission / reflection variable element 232. At this time, the transmission / reflection variable element 232 functions as a reflecting plate, and the reference light reflected by the transmission / reflection variable element 232 is incident on the hologram recorded on the optical information recording medium 1 again as phase conjugate light and signal light. Play back.

  When searching for information, the spatial light modulator 210 is used to add desired search information to the search light and irradiate the optical information recording medium 1 with the search light to reproduce the diffracted light. It is assumed that the transmission / reflection variable element 232 functions as a transmission plate during information retrieval. The diffracted light reproduced from the optical information recording medium 1 enters the lens 233, passes through the transmission / reflection variable element 232, and is collected on the photodetector 231. The reason why the optimal reference light angle can be detected by the light detector 231 and the arrangement configuration of the light detector 231 are the same as those in the first embodiment, and a description thereof will be omitted.

  The transmission / reflection variable element 232 may be configured to electrically change the transmission / reflection state of light as described above, or may be a mirror capable of transmitting a part of light.

  In this modification, the galvanometer mirror for phase conjugate light is not required, so that the optical system can be downsized, and the control can be easily performed because only one 217 galvanometer mirror is adjusted during reproduction. There are advantages.

  FIG. 8 shows a second embodiment of the optical system configuration of the pickup 11 in the optical information recording / reproducing apparatus 10. In FIG. 8, a lens 233 and a mirror 234 are arranged instead of the galvanometer mirror 222 and the actuator 221 in the optical system configuration of FIG. Further, a transmission / reflection variable element 232 is arranged instead of the galvano mirror 217, and a lens 235 and a photodetector 236 are arranged behind the transmission / reflection variable element 232. At the time of reproduction, the transmission / reflection variable element 232 functions as a reflection plate, and reflects the reference light from the light source 201 toward the optical information recording medium 1. The reference light transmitted through the optical information recording medium 1 enters the lens 233 and is collected on the mirror 234. The reference light reflected by the mirror 234 is incident on the hologram recorded on the optical information recording medium 1 again as phase conjugate light to reproduce the signal light.

  When searching for information, the spatial light modulator 210 is used to add desired search information to the search light and irradiate the optical information recording medium 1 with the search light to reproduce the diffracted light. It is assumed that the transmission / reflection variable element 232 functions as a transmission plate during information retrieval. The diffracted light reproduced from the optical information recording medium 1 enters the lens 233 and is condensed on the mirror 234. The diffracted light reflected by the mirror 234 enters the lens 233 and passes through the optical information recording medium 1 again. Thereafter, the diffracted light passes through the lens 220, the lens 219, and the transmission / reflection variable element 232, is collected by the lens 235, and is detected by the photodetector 236. The reason why the optimum reference beam angle can be detected by the photodetector 236 and the arrangement configuration of the photodetector 236 are the same as those in the first embodiment, and the description thereof will be omitted.

  The transmission / reflection variable element 232 may be configured to electrically change the transmission / reflection state of light as described above, or may be a mirror capable of transmitting a part of light.

  In this embodiment, since the galvanometer mirror for the phase conjugate light is not required, the apparatus can be miniaturized. Further, since only one 217 galvanometer mirror is required for adjustment during reproduction, there is an advantage that control can be facilitated.

  FIG. 9 shows a first modification of the second embodiment of the optical system configuration of the pickup 11 in the optical information recording / reproducing apparatus 10. In the optical system configuration of FIG. 5, in FIG. 9, a lens 237 and a mirror 238 are additionally provided in the optical path of the signal light. Further, a transmission / reflection variable element 232 is arranged instead of the galvano mirror 217, and a lens 235 and a photodetector 236 are arranged behind the transmission / reflection variable element 232. At the time of reproduction, the transmission / reflection variable element 232 functions as a reflection plate, and reflects the reference light from the light source 201 toward the optical information recording medium 1. The reference light transmitted through the optical information recording medium 1 is reflected by the galvanometer mirror 222 and incident on the hologram recorded on the optical information recording medium 1 again as phase conjugate light to reproduce the signal light.

  When searching for information, the spatial light modulator 210 is used to add desired search information to the search light and irradiate the optical information recording medium 1 with the search light to reproduce the diffracted light. It is assumed that the transmission / reflection variable element 232 functions as a transmission plate during information retrieval. The light transmitted through the optical information recording medium 1 enters the objective lens 237 and is reflected by the mirror 238. The light reflected by the mirror 238 is incident on the objective lens 237 again and irradiated on the optical information recording medium 1 to reproduce the diffracted light. The reproduced diffracted light passes through the lens 220, the lens 219, the transmission / reflection variable element 232, and the lens 235, and is condensed on the photodetector 236. The reason why the optimum reference beam angle can be detected by the photodetector 236 and the arrangement configuration of the photodetector 236 are the same as those in the first embodiment, and the description thereof will be omitted.

  The transmission / reflection variable element 232 may be configured to electrically change the transmission / reflection state of light as described above, or may be a mirror capable of transmitting a part of light.

  In this modification, since it is not necessary to adjust the galvanometer mirror, the time required for preparation for information retrieval can be shortened. Further, in the reproduction, in addition to the signal light by the phase conjugate light by the mirror 222, the signal light by the mirror 238 can be used, so there is an advantage that the reproduction efficiency can be improved.

  FIG. 10 shows a third embodiment of the optical system configuration of the pickup 11 in the optical information recording / reproducing apparatus 10. In FIG. 10, a quarter wavelength plate 239 is arranged on the front surface of the galvano mirror 222 instead of the polarization direction conversion element 214 in the optical system configuration of FIG. 5. At the time of reproduction, the reference light transmitted through the optical information recording medium 1 is transmitted through the quarter wavelength plate 239, reflected by the galvano mirror 222, and again transmitted through the quarter wavelength plate 239. By passing through the quarter-wave plate 239 twice, the polarization direction of the reference light is changed from s-polarized light to p-polarized light, and is incident again on the hologram recorded on the optical information recording medium 1 as phase conjugate light, and the signal light is Played.

  When searching for information, the spatial light modulator 210 is used to add desired search information to the search light and irradiate the optical information recording medium 1 with the search light to reproduce the diffracted light. The diffracted light reproduced from the optical information recording medium 1 is transmitted through the quarter wavelength plate 239, reflected by the galvanometer mirror 222, and again transmitted through the quarter wavelength plate 239. By passing through the quarter-wave plate 239 twice, the diffracted light is converted from s-polarized light to p-polarized light, and is incident on the hologram recorded on the optical information recording medium 1 again as phase conjugate light to reproduce the signal light. Is done. The reproduced signal light passes through the objective lens 213, the relay lens 211, and the spatial filter 212 and enters the polarization beam splitter 209. At this time, since the reproduction light is p-polarized light, it passes through the polarization beam splitter 209 and enters the photodetector 223. At the time of this search, the angle of the galvanometer mirror is continuously changed within the angle scanning range of the reference light, and the reproduction light amount at that time is detected by the photodetector 223. The presence or absence of similar information can be determined from the amount of reproduction light detected by the photodetector 223. When there is similar information, the optimum reference light angle for reproducing the similarity between the search information and the similar information and the similar information can be obtained from the light amount and the angle of the galvanometer mirror.

  FIG. 17 shows an example of the relationship between the light amount I detected by the photodetector 223 and the reference light angle θ calculated from the angle of the galvanometer mirror during information retrieval. The similarity between the search information and the information recorded on the optical recording medium 1 as a hologram is detected as the reproduction light quantity I. At this time, a reference value for an arbitrary reproduction light quantity is provided, and information having a light quantity larger than the reference value is similar information, and information having a light quantity smaller than the reference value is determined not to be similar information. The presence or absence of similar information in the hologram can be checked. For information that exceeds the reference value, it is possible to obtain an optimum reference light incident angle for reproducing similar information by obtaining the reference light angle when the reproduction light amount peak becomes maximum.

  FIG. 16 shows an example of an operation for searching for desired information according to this embodiment. In step 501, the disk rotation motor control circuit 88 and the access control circuit 81 are controlled so that the book to be reproduced faces the objective lens, and the disk is positioned. In step 502, the optical information recording medium 1 is irradiated with the search light with the desired search information added, and the reproduced diffracted light is reflected by the galvano mirror 222 and detected by the photodetector 223. Judgment is made. In step 503, the process branches depending on the presence / absence of similar information. If there is no similar information, the process proceeds to a search for another book in step 505. If there is similar information, in step 504, the light quantity and the galvano at that time The optimum reference beam angle for reproducing the similarity and the similar information is acquired from the angle of the mirror 222. In step 506, a reproduction page is determined from the similar information. After the reproduction page is determined, in step 507, the angles of the galvanometer mirror 217 and the galvanometer mirror 222 are set based on the optimum reference light angle information acquired in step 503. In step 508, the reference light is irradiated onto the hologram recorded on the optical information recording medium 1 to reproduce the signal light. In step 509, it is determined whether or not other similar information is to be reproduced. If other similar information is to be reproduced, the process returns to step 506. Proceed to determine whether to search. If it is determined in step 505 that another book is to be searched, the process returns to step 501, and if no other book is to be searched, the search process is terminated.

In this embodiment, the optical system can be configured with the same number of parts as the optical system configuration of FIG. 2, and there is an advantage that the apparatus can be downsized.
As described above, according to the optical information recording / reproducing apparatus according to the present invention, by detecting the diffracted light reproduced by irradiating the optical information recording medium with the search light added with the desired search information, The presence or absence of information similar to the search information in the irradiated hologram can be checked, and if there is similar information, information on the similarity and the optimum reference beam angle for reproduction can be obtained.

  Although the description has been mainly given of the case of the recording / reproducing apparatus so far, the present invention can be similarly applied to the case of the reproducing apparatus and the search apparatus.

DESCRIPTION OF SYMBOLS 1 ... Optical information recording medium, 10 ... Optical information recording / reproducing apparatus, 11 ... Pickup,
12 ... Phase conjugate optical system, 13 ... Disc Cure optical system,
14 ... Optical system for detecting the disk rotation angle, 50 ... Rotation motor,
81 ... Access control circuit, 82 ... Light source driving circuit, 83 ... Servo signal generation circuit,
84 ... Servo control circuit, 85 ... Signal processing circuit, 86 ... Signal generation circuit,
87 ... Shutter control circuit, 88 ... Disc rotation motor control circuit,
89 ... Controller,
201 ... light source, 202 ... collimating lens, 203 ... shutter,
204 ... 1/2 wavelength plate (optical rotator), 205 ... polarizing beam splitter,
206: Signal light, 207: Reference light, 208: Beam expander,
209 ... Polarizing beam splitter, 210 ... Spatial light modulator, 211 ... Relay lens,
212 ... Spatial filter, 213 ... Objective lens, 214 ... Polarization direction conversion element,
215 ... mirror, 216 ... mirror, 217 ... mirror, 218 ... actuator,
219 ... lens, 220 ... lens, 221 ... actuator, 222 ... mirror,
223 ... photodetector, 230 ... lens, 231 ... photodetector,
232 ... Transmission / reflection variable element, 233 ... lens, 234 ... mirror, 235 ... lens,
236 ... photodetector, 237 ... objective lens, 238 ... mirror, 239 ... 1/4 wavelength plate

Claims (7)

In an optical information recording / reproducing apparatus that records information on an optical information recording medium and reproduces information from the optical information recording medium using holography using signal light and reference light,
A light source;
A mechanism for forming reference light from the light source;
A mechanism for forming signal light from the light source;
A spatial light modulator for adding information to search light, which is a search light beam that passes through the same path as the signal light and the signal light;
A mechanism for irradiating the optical information recording medium with the signal light to which information is added and the search light;
An angle control mechanism for irradiating the optical information recording medium with the reference light from a desired angle;
A first detection mechanism for detecting signal light reproduced by irradiating the optical information recording medium with the reference light;
A mechanism for performing signal processing for processing information received by the first detection mechanism and reproducing the information;
A second detection mechanism that irradiates the optical information recording medium with the desired search information added thereto and receives a plurality of diffracted lights with different exit angles reproduced from the optical information recording medium;
The second detection mechanism includes a mirror, an actuator that controls the angle of the mirror, a lens, and a photodetector. When searching for desired information, the angle of the reproduced diffracted light is fixed by the actuator. Reflected by the mirror, and collected and detected by the lens on the photodetector,
The information similar to the search information in the information multiplexed and recorded on the optical information recording medium is checked using the light amounts of the plurality of diffracted lights received by the second detection mechanism, and the similar information is present. In this case, the light intensity of the diffracted light is used to find the similarity between the search information and the similar information, and the refracted light emission angle information is used to find the optimum reference light incident angle for reproducing the similar information. An optical information recording / reproducing apparatus. In an optical information recording / reproducing apparatus that records information on an optical information recording medium and reproduces information from the optical information recording medium using holography using signal light and reference light,
A light source;
A mechanism for forming reference light from the light source;
A mechanism for forming signal light from the light source;
A spatial light modulator for adding information to search light, which is a search light beam that passes through the same path as the signal light and the signal light;
A mechanism for irradiating the optical information recording medium with the signal light to which information is added and the search light;
An angle control mechanism for irradiating the optical information recording medium with the reference light from a desired angle;
A first detection mechanism for detecting signal light reproduced by irradiating the optical information recording medium with the reference light;
A mechanism for performing signal processing for processing information received by the first detection mechanism and reproducing the information;
A second detection mechanism that irradiates the optical information recording medium with the desired search information added thereto and receives a plurality of diffracted lights with different exit angles reproduced from the optical information recording medium;
The second detection mechanism includes a transmission / reflection variable element that can switch between transmission and reflection, an actuator that controls the angle of the transmission / reflection variable element, a lens, and a photodetector, and reproduces desired information. The transmission / reflection variable element functions as a reflection plate, and when the desired information is searched, the reproduced diffracted light is transmitted by the transmission / reflection variable element and collected by the lens to the photodetector. Detect light,
The information similar to the search information in the information multiplexedly recorded on the optical information recording medium is checked by using the light amounts of the plurality of diffracted lights received by the second detection mechanism, and the similar information is present. In this case, the light intensity of the diffracted light is used to find the similarity between the search information and the similar information, and the refracted light emission angle information is used to find the optimum reference light incident angle for reproducing the similar information. An optical information recording / reproducing apparatus. In an optical information recording / reproducing apparatus that records information on an optical information recording medium and reproduces information from the optical information recording medium using holography using signal light and reference light,
A light source;
A mechanism for forming reference light from the light source;
A mechanism for forming signal light from the light source;
A spatial light modulator for adding information to search light, which is a search light beam that passes through the same path as the signal light and the signal light;
A mechanism for irradiating the optical information recording medium with the signal light to which information is added and the search light;
An angle control mechanism for irradiating the optical information recording medium with the reference light from a desired angle;
A first detection mechanism for detecting signal light reproduced by irradiating the optical information recording medium with the reference light;
A mechanism for performing signal processing for processing information received by the first detection mechanism and reproducing the information;
A second detection mechanism that irradiates the optical information recording medium with the desired search information added thereto and receives a plurality of diffracted lights with different exit angles reproduced from the optical information recording medium;
The second detection mechanism includes a transmission / reflection variable element that can switch between transmission and reflection, a lens, and a photodetector. When reproducing desired information, the transmission / reflection variable element functions as a reflection plate. When searching for desired information, the reproduced diffracted light is incident on the lens, transmitted by the transmission / reflection variable element, condensed on the photodetector, and detected.
The information similar to the search information in the information multiplexedly recorded on the optical information recording medium is checked by using the light amounts of the plurality of diffracted lights received by the second detection mechanism, and the similar information is present. In this case, the light intensity of the diffracted light is used to find the similarity between the search information and the similar information, and the refracted light emission angle information is used to find the optimum reference light incident angle for reproducing the similar information. An optical information recording / reproducing apparatus. In an optical information recording / reproducing apparatus that records information on an optical information recording medium and reproduces information from the optical information recording medium using holography using signal light and reference light,
A light source;
A mechanism for forming reference light from the light source;
A mechanism for forming signal light from the light source;
A spatial light modulator for adding information to search light, which is a search light beam that passes through the same path as the signal light and the signal light;
A mechanism for irradiating the optical information recording medium with the signal light to which information is added and the search light;
An angle control mechanism for irradiating the optical information recording medium with the reference light from a desired angle;
A first detection mechanism for detecting signal light reproduced by irradiating the optical information recording medium with the reference light;
A mechanism for performing signal processing for processing information received by the first detection mechanism and reproducing the information;
A second detection mechanism that irradiates the optical information recording medium with the desired search information added thereto and receives a plurality of diffracted lights with different exit angles reproduced from the optical information recording medium;
The second detection mechanism includes a first lens, a mirror, a second lens, and a photodetector, and the angle control mechanism includes a transmission / reflection variable element capable of switching between transmission and reflection, and the transmission / reflection. The actuator is configured to control the angle of the variable element. When reproducing desired information, the transmission / reflection variable element functions as a reflector, and when retrieving desired information, the reproduced diffracted light is used. , Condensed on the mirror by the first lens, reflected by the mirror, transmitted through the transmission / reflection variable element, condensed on the photodetector by the second lens, and detected.
The information similar to the search information in the information multiplexedly recorded on the optical information recording medium is checked by using the light amounts of the plurality of diffracted lights received by the second detection mechanism, and the similar information is present. In this case, the light intensity of the diffracted light is used to find the similarity between the search information and the similar information, and the refracted light emission angle information is used to find the optimum reference light incident angle for reproducing the similar information An optical information recording / reproducing apparatus. In an optical information recording / reproducing apparatus that records information on an optical information recording medium and reproduces information from the optical information recording medium using holography using signal light and reference light,
A light source;
A mechanism for forming reference light from the light source;
A mechanism for forming signal light from the light source;
A spatial light modulator for adding information to search light, which is a search light beam that passes through the same path as the signal light and the signal light;
A mechanism for irradiating the optical information recording medium with the signal light to which information is added and the search light;
An angle control mechanism for irradiating the optical information recording medium with the reference light from a desired angle;
A first detection mechanism for detecting signal light reproduced by irradiating the optical information recording medium with the reference light;
A mechanism for performing signal processing for processing information received by the first detection mechanism and reproducing the information;
A second detection mechanism that irradiates the optical information recording medium with the desired search information added thereto and receives a plurality of diffracted lights with different exit angles reproduced from the optical information recording medium;
The second detection mechanism includes a first lens, a mirror, a second lens, and a photodetector, and the angle control mechanism includes a transmission / reflection variable element that can switch between transmission and reflection, and transmission / reflection. It is composed of an actuator that controls the angle of the variable element, and when reproducing desired information, the transmission / reflection variable element functions as a reflector, and when searching for desired information, instead of the diffracted light, When the search light to which the search information is added is irradiated onto the optical information recording medium, the transmitted light transmitted from the optical information recording medium is converted into parallel light by the first lens, reflected by the mirror, and Condensed on the optical information recording medium by the lens of, and regenerated diffracted light is transmitted through the transmission / reflection variable element, and is condensed and detected by the second lens on the photodetector,
The information similar to the search information in the information multiplexedly recorded on the optical information recording medium is checked by using the light amounts of the plurality of diffracted lights received by the second detection mechanism, and the similar information is present. In this case, the light intensity of the diffracted light is used to find the similarity between the search information and the similar information, and the refracted light emission angle information is used to find the optimum reference light incident angle for reproducing the similar information. An optical information recording / reproducing apparatus. In an optical information recording / reproducing apparatus that records information on an optical information recording medium and reproduces information from the optical information recording medium using holography using signal light and reference light,
A light source;
A mechanism for forming reference light from the light source;
A mechanism for forming signal light from the light source;
A spatial light modulator for adding information to search light, which is a search light beam that passes through the same path as the signal light and the signal light;
A mechanism for irradiating the optical information recording medium with the signal light to which information is added and the search light;
An angle control mechanism for irradiating the optical information recording medium with the reference light from a desired angle;
A first detection mechanism for detecting signal light reproduced by irradiating the optical information recording medium with the reference light;
A mechanism for performing signal processing for processing information received by the first detection mechanism and reproducing the information;
A second detection mechanism that irradiates the optical information recording medium with the desired search information added thereto and receives a plurality of diffracted lights with different exit angles reproduced from the optical information recording medium;
The first detection mechanism is configured by a photodetector, and the second detection mechanism is configured by a quarter wavelength plate, a mirror, an actuator for controlling the angle of the mirror, and the photodetector. When retrieving information, the reproduced diffracted light is transmitted through the quarter-wave plate, reflected by the mirror, transmitted through the quarter-wave plate again, and irradiated to the optical information recording medium,
Reproduction light diffracted from the optical information recording medium is detected by the photodetector,
The information similar to the search information in the information multiplexedly recorded on the optical information recording medium is checked by using the light amounts of the plurality of diffracted lights received by the second detection mechanism, and the similar information is present. In this case, the light intensity of the diffracted light is used to find the similarity between the search information and the similar information, and the refracted light emission angle information is used to find the optimum reference light incident angle for reproducing the similar information. An optical information recording / reproducing apparatus. In an optical information recording / reproducing method for recording information on an optical information recording medium and reproducing information from the optical information recording medium using holography using signal light and reference light,
Adding desired search information to search light that is a search light beam that passes through the same path as the signal light, and irradiating the optical information recording medium with the search light;
A plurality of diffracted lights having different emission angles reproduced from the optical information recording medium are sequentially reflected by an angle variable mirror and incident on the optical information recording medium, and the light information recording medium is used by using the amount of the diffracted reproducing light. Checking the presence or absence of similar information with the search information in the information recorded in multiple
When there is the similar information, the similarity information is reproduced using the similarity between the search information and the similar information using the light quantity of the reproduction light, and the angle of the mirror when the reproduction light is generated. And an optical information recording / reproducing method including a step of finding an optimum reference light incident angle in order to achieve this.

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