Abstract:
The optical information recording and reproducing device utilizing holography requires the optical system to generate the signal beam and the reference beam to be irradiated to the holographic storage medium as well as another optical system to generate the curing light beam to be irradiated to the holographic storage medium. Furthermore, from the viewpoint of backward compatibility, if the same device is used for recording or reproduction on the conventional optical discs represented by Blu-ray Disc, another optical system adaptable to recording and reproduction on these optical disks is required. This means the optical system configurations become complicated and larger in size. One solution for downsizing is to use the reference beam also as the curing light beam. Another way is sharing of optical path for curing light beam and for the reference beam. Furthermore, it is possible to share the light source for generating the curing light beam and for generating the recording or reproducing light beam. In such way, optical system configurations become simple.

Description:
BACKGROUND 
     This invention relates to devices of recording and/or reproducing information on holographic storage medium. 
     It is desired that in the near future, optical disks will be enlarged in capacity to a level of 100 GB to 1 TB, that is, to the same level as a HDD (Hard Disk Drive). 
     However, in order to realize such a large capacity optical disk, it will be necessary to develop a new storage technology different from the past trend of high-density technology as indicated by the use of shorter wavelength and higher NA objective lenses. 
     Holographic recording is a promising technology for future optical data storage with larger capacity and higher transfer rate. 
     In the holographic technology, data information is recorded through interference patterns of signal beam modulated two-dimensionally by a spatial light modulator and reference beam in holographic storage medium. 
     And data information is reproduced two-dimensionally by means of CMOS, CCD, and other photo detectors 
     These features are effective for large-capacity, high-speed recording and reproduction of information. 
     The hologram recording technology is referred to, for example, in Japanese Patent Application Laid-open Publication No. 2004-272268-A (Patent Document 1) and Non-Patent Document 1. These documents carry descriptions about the so-called angular multiplexing recording method. Furthermore, the same Patent Document 1 also describes a technology that can make array distances between adjoining holograms narrower by placing a spatial filter (polytopic filter) at the beam waist of the signal beam and can increase recording density and capacity as compared with the conventional angular multiplexing recording method. 
     The hologram recording technology is also taken up, for example, in WO 2004-102542 (Patent Document 2). This Patent Document 2 describes an example about shift multiplexing method. In this method, hologram is recorded by interference of signal beam from the inner pixels in a spatial light modulator and reference beam from the outer pixels in the ring-belt shape zone in the same modulator. 
     Another related art is also found in Japanese Patent Application Laid-open Publication No. 11-311938-A (Patent document 3). This Patent Document 3 discloses an example about cure system to cure a recorded hologram.
     [Patent Document 1] Japanese Patent Application Laid-open Publication No. 2004-272268-A   [Patent Document 2] WO 2004-102542   [Patent Document 3] Japanese Patent Application Laid-open Publication No. 11-311938-A   [Non-patent Document 1] “The InPhase Professional Archive Drive OMA; Design and Function,” Ian Redmond; Optical Data Storage Topical Meeting 2006.   

     SUMMARY 
     Incidentally, as described in “The InPhase Professional Archive Drive OMA; Design and Function,” Ian Redmond; Optical Data Storage Topical Meeting 2006, (Non-patent Document 1), it becomes necessary to separately prepare an optical system to create light beam for cure, namely, for pre-cure and post-cure, and irradiate the recording medium, in addition to the optical system to generate the signal beam and the reference beam to irradiate the recording medium. The Patent Document 3 combines the above two optical systems together into one optical system. However, this configuration has a problem in performing uniform cure treatment, because the cure beam is irradiated with a convergent beam and, therefore, is difficult to be distributed evenly in light intensity in its irradiating ambits in the recording medium, thus causing a mixture of insufficiently cured ambit and overly cured ambit. 
     Furthermore, if we desire to record and reproduce the conventional optical disks as represented by Blu-ray Disc on the same device, it is necessary to add an optical system adaptable to recording and reproduction on these conventional optical discs from the viewpoint of backward compatibility. 
     For the purpose of downsizing drive system, it is desirable that optical system should be made as sharable as possible, but the technology on the optical system configuration to satisfy the above-mentioned requirement have not been disclosed at all in the past. 
     The present invention has been made in view of the foregoing problems, with the aim of achieving simplification of drive system. 
     The aim of the present invention can be attained, for example, by sharing the same optical path for both of the reference light beam and the curing light beam. 
     According to the present invention, we can downsize the optical information recording and reproducing device utilizing holography, and achieve backward compatibility. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, objects and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings wherein: 
         FIG. 1  is a block diagram showing an example of optical information recording and reproducing device; 
         FIG. 2  is a schematic diagram illustrating an example of pickup of an optical information recording and reproducing device; 
         FIG. 3  is a schematic diagram illustrating an example of pickup of an optical information recording and reproducing device; 
         FIG. 4  is a schematic diagram illustrating an example of pickup of an optical information recording and reproducing device; 
         FIG. 5  is a schematic diagram illustrating an example of pickup of an optical information recording and reproducing device; 
         FIG. 6  is a schematic diagram illustrating an example of pickup of an optical information recording and reproducing device; 
         FIG. 7  is a block diagram showing an example of operational flow of an optical information recording and reproducing device; 
         FIG. 8  is a schematic diagram illustrating an example of pickup of an optical information recording and reproducing device; 
         FIG. 9  is a schematic diagram illustrating an example of pickup of an optical information recording and reproducing device; and 
         FIG. 10  is a schematic diagram illustrating an example of pickup of an optical information recording and reproducing device. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Explanation is made below of the examples of the present invention. 
       FIG. 1  shows the overall configuration of an optical information recording and reproducing device which utilizes holography to record and/or reproduce digital information. 
     The optical information recording and reproducing device  10  includes the pickup  11 , the phase conjugate optical system  12 , the disk cure optical system  13 , the disk rotating angle detecting optical system  14 , and the rotating motor  50 . The optical information recording medium  1  is configured rotatable by the rotating motor  50 . 
     The pickup  11  has the functions to output the reference light and the signal light to the optical information recording medium  1  so as to record digital information by utilizing the holography. 
     In this case, the information signal to be recorded is sent out from the controller  89  and via the signal generating circuit  86  to the spatial light modulator (to be described later) located within the pickup  11 , where the signal light is modulated. 
     In order to reproduce the information stored in the light information recording medium  1 , the phase conjugate light of the reference light outputted from the pickup  11  is to be generated by the phase conjugate optical system  12 . The phase conjugate light referred to above is the light wave that has the same wave surface as the input light but moves toward the opposite direction. The reconstruction light reconstructed by the above phase conjugate light is to be detected by the light detector (to be described later) located within the pickup  11  and reconstructed by the signal treating circuit  85 . 
     The irradiation time during which the reference light and the signal light are irradiated to the optical information recording medium  1  is adjustable by controlling the opening-closing cycle of the shutter (to be described later) within the pickup  11 , by means of the controller  89  via the shutter control circuit  87 . 
     The disk cure optical system  13  plays the role of creating a light beam used for precure and post-cure of the optical information recording medium  1 . What is called “precure” here is the preliminary process wherein, when recording of certain optical information is to be made in a desired position within the optical information recording medium  1 , a predetermined light beam is irradiated to that desired position before irradiation of the reference light and the signal light to that desired position. Likewise, “post-cure” means the post-process wherein, after recording of certain optical information has been made in a desired position within the optical information recording medium  1 , a predetermined light beam is irradiated to that desired position to make it write prohibit. 
     The disk rotation angle detecting optical system  14  is used to find out the rotation angle of the optical information recording medium  1 . When to adjust the optical information recording medium  1  to a predetermined rotation angle, the disk rotation angle detecting optical system  14  functions to detect the signal corresponding to the rotation angle, and the detected signal is used to operate the controller  89  and, via the disk rotating motor control circuit  88 , to be able to control the rotation angle of the optical information recording medium  1 . 
     From the light source drive circuit  82 , predetermined light source drive current is supplied to the light sources in the pickup  11 , the disk cure optical system  13 , and the disk rotation angle detecting optical system  14 , thus enabling each light source to emit light with predetermined light intensity. 
     Also, the pickup  11 , the phase conjugate optical system  12 , or the disk cure optical system  13  has a mechanism to make each position slidable in the radius direction of the optical information recording medium  1  with position control undertaken by the access control circuit  81 . 
     By the way, because the recording technology based on the holography is a technology that can record ultra-high-density information, allowable margin of error in regard to gradient and shift of the optical information recording medium  1 , for example, is inclined to become extremely small. Therefore, it may well be practiced firstly to provide, in the pickup  11 , some mechanism to detect amount of shift derived from causes of shift for which allowable margin of error is small, such as gradient and displacement of the optical information recording medium  1 , secondly to generate servo control signal in the servo signal generating circuit  83 , and thirdly to provide a servo mechanism in the optical information recording and reproducing device  10  so as to correct such amount of shift through the servo control circuit  84 . 
     From the viewpoint of downsizing of the optical information recording and reproducing device  10 , it may well be exercised to do simplifying by grouping some or all of the optical systems in regard to the pickup  11 , the phase conjugate optical system  12 , the disk cure optical system  13 , and the disk rotation angle detecting optical system  14 . 
     An example of the optical system configuration in case the pickup  11  and the disk cure optical system  13  are grouped into one is shown in  FIG. 2 . 
     In  FIG. 2 , the light beam outputted from the light source  301  is transmitted through the collimator lens  302  and is incident on the shutter  303 . When the shutter  303  is open, the light beam after transmitted through the shutter  303  is to be regulated as to the polarization direction by the optical element  304  composed of, for example, a ½ wavelength plate, etc., so that ratio of P-polarized to S-polarization by light volume may become as desired, and then, to be incident on the PBS (polarization beam splitter) prism  305 . 
     The light beam transmitted through the PBS prism  305  is expanded in light beam diameter by the beam expander  309 . After that and through the phase mask  311 , the relay lens  310 , and the PBS prism  307 , the light beam is to be incident on the spatial light modulator  308 . 
     The signal light beam with the information added by the spatial light modulator  308  is transmitted through the PBS prism  307 , and propagated through the relay lens  312  and the spatial filter  313 . The signal light beam is then collected at the optical information recording medium  1  by means of the objective lens  325 . 
     On the other hand, the light beam reflected by the PBS prism  305  is to function as the reference light beam, to be set as to its polarization direction depending on whether for recording or for reproduction by the polarization direction transformation unit  324 , and then to be incident on the mirrors  314  and  315  through the galvano-mirror  316 . Since the angle of the galvano-mirror  316  is adjustable by the actuator  317 , the reference light beam which is to incident on the information recording medium  1  after transmitted through the lenses  319  and  320  can be set as desired in respect of its incident angle. 
     By making the signal light beam and the reference light beam are thus made to be incident on the optical information recording medium  1  in such manner that each light beam overlap the other, patterns of interference fringes are formed inside the recording medium, and recording of the information is finished by writing these patterns in the recording medium. Further, recording in multiple angles is possible, since angle of incidence of the reference light beam to be incident on the optical information recording medium  1  can be varied by means of the galvano-mirror  316 . 
     In the case of reproducing recorded information, the reference light beam is made to be incident on the optical information recording medium  1 , and when the light beam having been transmitted through the optical information recording medium  1  is reflected by the galvano-mirror  321 , its phase conjugate light is to be created. 
     The reconstruction light beam reconstructed by the above phase conjugate light is to be propagated through the objective lens  325 , the relay lens  312 , and the spatial filter  313 . After that, the reconstruction light beam is reflected by the PBS prism  307  before being incident on the light detector  318  for reproduction of the recorded signal. 
     In order to perform precure and post-cure of the optical information recording medium  1 , the reference light beam is to be used as the curing light beam and irradiated in a state of parallel beam to the optical information recording medium  1  for curing, realizing common use of the light path. In this manner, the curing light beam can be made even in terms of light intensity in the irradiation ambits, bringing about advantage in making the curing treatment uniform without leaving mixture of insufficiently cured portions and overly cured portions. 
     Also, the light beam for cure treatment traces the light path, which the above reference light beam has just followed, for at least a part of that light path from the above splitter to the recording medium, and attains the aim of applying the cure treatment to the recording medium, thereby realizing downsizing of the device. 
     Generally speaking, the signal light beam and the reference light beam are required to be light beams of high coherence such as tunable laser beams from the holographic viewpoint, but from the viewpoint of signal quality, the curing light beam is required to be a light beam of low coherence so as not to form futile holograms causative of noises. 
     To satisfy the above requirements, it may well be exercised, as shown in  FIG. 3 , for example, to provide the laser light source  331  which can output a light beam of lower coherence than the laser light source  301 . As  FIG. 3  shows, the curing light beam  333  is outputted from the laser light source  331 , goes through the collimator lens  332  and the diffuser plate  334 , and reaches the PBS prism  335  where the curing light beam is combined with the light path of the reference light beam by the PBS prism  335  to be finally irradiated to the optical information recording medium  1 . 
     Although each light beam is required to have different characteristic in point of coherence as explained above, the provisions of two laser light sources, such as the high-coherent laser light source  301  and the low-coherent laser light source  331 , can realize an optical system configuration satisfying the requirements regarding coherence, while sharing is made of the optical system. Most of the light path is shared by the curing light beam and the reference light beam, offering advantage in achieving downsizing of the device. 
     Further, by developing the optical system configuration shown in  FIG. 3 , the present invention is capable to record or reproduce information in the optical disks of BDs or HD-DVDs. Further explanation is given below with reference to  FIG. 8 . 
     When the holography is utilized for recording or reproducing signals, explanation has been made in the present example and referring to  FIG. 3 ; that is, the light beam outputted from the laser light source  301  which produces a light beam of high coherence is used for the signal light beam as well as the reference light beam, while the light beam outputted from the laser light source  331  which produces a light beam of lower coherence than the laser light source  301  is used for the curing light beam. 
     When recording or reproduction of information is made on the optical disk  101  such as BD and HD-DVD in the present example, the light beam outputted from the laser light source  331  is used since the low-coherent light beam has to be used to suppress laser noises. In other words, the present example is characterized in that the light source producing light beam is shared between the curing light beam and the light beam for recording or reproduction of BDs and HD-DVDs. The driver circuit for the laser light source  331  may well be connected with a high frequency superposed circuit so as to produce a laser light of low coherence. 
     Which the light beam outputted from the laser light source  331  is irradiated to, the optical information recording medium  1  as the light beam for curing or to the optical disk  101  as the light beam for recording or reproduction on BDs or HD-DVDs, is to be chosen by controlling the light volume irradiated according to the combination of the polarization direction transformation unit  334  and the PBS prism  335 . The polarization direction transformation unit  334  can achieve its purpose by insertion or withdrawal of a liquid crystal element and a wavelength plate. 
     In case information is recorded or reproduced on the optical disks  101  such as BDs and HD-DVDs, the polarization direction is to be controlled so that the light beam exiting from the polarization direction transformation unit  334  may have P-polarization. This enables the light beam to be incident on the PBS prism  335  and the PBS prism  404  to be transmitted through and to be led to the light path of the beam expander  405 . 
     The light beam transmitted through the beam expander  405  proceeds, via the starting mirror  406  and the ¼ wavelength plate  407 , to be incident on the objective lens  408  in a state of circularly polarized light and is to be collected on the information recording plane of the optical disk  101 . The light beam reflected on the optical disk  101  takes the light path it has come reversely, and is transmitted through the objective lens  408 , the ¼ wavelength plate  407 , the starting mirror  406 , and the beam expander  405 , and is reflected at the beam splitter  404 . The light beam after reflected at the beam splitter  404  is transmitted through the collimator lens  409 , and a required light beam is diffraction-split by the diffraction grating  410  on the detection side and collected at the photodetector  411  so as to be able to detect required servo signals. 
     In the case of curing the optical information recording medium  1 , the light beam exiting from the polarization direction transformation unit  334  is so controlled in polarization direction as to become S-polarized light; thus the light beam is to be reflected upon being incident on the PBS prism  335  and is able to be led to the light path of the reference light beam. By utilizing the light path for the reference light beam, the light beam from the laser light source  331  is led to the optical information recording medium  1  to carry out precuring and post-curing of the recording medium  1 . 
     As described above, the same light source is shared for generating the light beams for curing and for recording or reproducing on BDs or HD-DVDs. Moreover, sharing of a large portion of the light path is also made for the curing light beam and the reference light beam. Such sharing in the light source and the light path makes it possible to wrap up a plurality of optical system configurations rationally in one cabinet, offering a great advantage in downsizing of the device. 
     Besides, the same rotary motor may well be used in the present invention for the optical information recording medium  1  as well as the optical disk  101  such as BDs or HD-DVDs. Or otherwise, separate rotary motors may well be provided for individual uses and driven by the disk rotating motor control circuit. 
     Also, the optical information recording medium  1  in the present invention may well take the shape of a card. 
     The optical system configuration is not limited to what are shown in  FIG. 2  and  FIG. 3 , but may well be set up as shown in  FIG. 4 . Now, explanation is given hereinbelow in reference to  FIG. 4 . 
     The light beam outputted from the light source  201  is transmitted through the collimator lens  202  to be incident on the shutter  203 . When the shutter  203  is open, the light beam after passing through the shutter  203  is to receive control on polarization direction by the optical element  204  composed of a ½ wavelength plate, for example, and others so that the ratio of P-polarized light and S-polarized light in terms of light volume may become as required. The light beam is then incident on the PBS prism  205 . 
     The light beam transmitted through the PBS prism  205  proceeds through the PBS prism  207  to be incident on the spatial light modulator  208 . 
     The signal light beam  206  with information added by the spatial light modulator is reflected at the PBS prism  207  and propagated through the angle filter  209  which admits only the light beam having a certain predetermined angle of incidence. After that, the signal light beam collects on the optical information recording medium  1 . 
     On the other hand, the light beam reflected at the PBS prism  205  functions as the reference light beam  212  and is set up by the polarization direction transformation unit  219  so as to have a predetermined polarization direction depending on whether for recording or for reproduction. The polarized light beam then advances via the mirrors  213  and  214  before being incident on the lens  215 . 
     The lens  215  performs the role of collecting the reference light beam  212  on the back focus plane of the objective lens  210 , and the reference light beam that has once focused on the back focus plane of the objective lens  210  is again turned into a nearly parallel light beam by the objective lens  210 , in which form it is to be incident on the optical information recording medium  1 . 
     The objective lens  210  or the optical block  221  is movable, for example, in the direction indicated by the arrow mark  220 . By sliding the position of the objective lens  210  or the optical block  221  along the movable direction  220 , the relative positions of the objective lens  210  and the focus point in the back focus plane of the objective lens  210  changes, thereby allowing the angle of incidence to be set at a desired angle when the reference light beam is to be incident on the optical information recording medium  1 . 
     By making the signal light beam and the reference light beam enter the optical information recording medium  1  together overlapping each other, interference fringe patterns are to be formed. Writing these patterns in the recording medium completes recording of information. Also, by sliding the position of the objective lens  210  or the optical block  221  along the movable direction  220 , the angle of incidence at which the reference light beam is to be incident on the optical information recording medium can be changed, and this enables multi-angle recording. 
     In case of reproducing recorded information, as above-mentioned, the reference light beam is made to be incident on the optical information recording medium  1 , and the light beam which is transmitted through the optical information recording medium  1  is to be reflected by the galvano mirror  216 , thereby producing its phase conjugate light. 
     The reconstruction light beam reconstructed by the phase conjugate light is propagated through the objective lens  210  and the angle filter  209 . After that, the reconstruction light beam is transmitted through the PBS prism  207 , is incident on the light detector and is able to reproduce recorded signals. 
     Since the optical system shown in  FIG. 4  is of the configuration in which both the signal light beam and the reference light beam are made to enter the same objective lens, it has a merit in that it can be downsized drastically as compared with the optical system configurations shown in  FIG. 2  and  FIG. 3 . 
     When to conduct precure and post-cure of the optical information recording medium  1  in the above regard, the reference light beam is used as the light beam for curing. 
     Also, from the viewpoint of coherence mentioned above, the light source for the curing light beam as referred to in  FIG. 5  may well be served by the additionally installed laser light source  331  which can emit a light beam of lower coherence than the laser light source  201 . As  FIG. 5  shows, the curing light beam  333  comes out from the laser light source  331 , and is propagated through the collimator lens  332 , and the diffuser plate  334 , before it is combined with the light path of the reference light beam by the PBS prism  205  and irradiated to the optical information recording medium  1 . 
     By making two laser light sources available, it becomes possible to realize the optical system configuration that can meet what is required of the light beam in regard to coherence while keeping sharing the optical system. Furthermore, the fact that the curing light beam and the reference light beam share most of their light paths is advantageous for downsizing of the device. 
     In addition, the present invention has the possibility of developing the optical system configuration shown in  FIG. 5  and enabling recording and reproducing information on the optical disks such as BDs and HD-DVDs. Explanation is given below referring to  FIG. 6 . 
     In case of recording or reproducing information on the basis of holography, as explained in the present example and in reference to  FIG. 5 , the light beam outputted from the laser light source  201  which emits a high-coherent light beam is to be used as the signal light beam and the reference light beam, and the light beam outputted from the laser light source  331  which emits a light beam of lower coherence than the laser light source  201  is to be used as the light beam for curing. 
     In case of recording or reproducing information on the optical disk  101  such as BDs or HD-DVDs in the present example, the light beam having low coherence, that is, the light beam outputted from the laser light source  331 , is used to suppress laser noise. In other words, the present invention is characterized in that the light source is shared for generating the light beam for curing as well as for generating the light beam for recording and reproducing on BDs and HD-DVDs. 
     Whether the light beam outputted from the laser light source  331  is to be irradiated to the optical information recording medium  1  as the curing light beam or to be irradiated to the optical disk  101  as the light beam for recording or reproducing on BDs or HD-DVDs can be selected by controlling the light volume for irradiation by properly combining the polarization direction transformation unit  403  with the PBS prism  404 . The function of the polarization direction transformation unit  403  can be attained by means of the liquid crystal element or the wavelength plate to be inserted or withdrawn. 
     For example, in case information is recorded or reproduced on the optical disk  101  such as BDs or HD-DVDs, polarization direction is to be controlled so that the light beam outputted from the polarization direction transformation unit  403  may become S-polarized light. Thereby, the light beam incident on the PBS prism  404  can be reflected and guided to the light path of the beam expander  405 . 
     The light beam transmitted through the beam expander  405  proceeds via the starting mirror  406  and the ¼ wavelength plate  407 , before being incident on the objective lens  408  in a state of circularly polarized light and being collected on the information recording plane of the optical disk  101 . The light beam reflected on the optical disk  101  takes the light path it has come reversely, and is transmitted via the objective lens  408 , the ¼ wavelength plate  407 , the starting mirror  406 , and the beam expander  405 , and further through the beam splitter  404 . The light beam after transmitted through the beam splitter  404  is further transmitted through the collimator lens  409 , and a required light beam is diffraction-split by the detection-side diffraction grating  410  and collected at the photodetector  411  so as to be able to detect required servo signals. 
     When to apply curing to the optical information recording medium  1 , polarization direction is to be controlled so that the light beam outputted from the polarization direction transformation unit  403  may become P-polarized light. Thereby, the light beam incident on the PBS prism  404  can be transmitted through and guided to the light path of the reference light beam. By guiding the light beam from the laser light source  331  to the optical information recording medium  1  availing of the light path of the reference light beam, it becomes possible to exercise precure and post-cure of the optical information recording medium  1 . 
     As described above, the light source is shared for generating the light beam for curing as well as for generating the light beam for recording and reproducing of BDs or HD-DVDs, and at the same time, most of the light path is also shared for the curing light beam and for the reference light beam. Such sharing in the light source and the light path makes it possible to wrap up a plurality of optical system configurations rationally in one cabinet, offering a great advantage in downsizing of the device. 
     Besides, the same rotary motor may well be used in the present invention for driving the optical information recording medium  1  as well as for driving the optical disk  101  such as BDs or HD-DVDs. Or otherwise, separate rotary motors may well be provided for individual uses and driven by the disk rotating motor control circuit. 
     Also, the optical information recording medium  1  in the present invention may well take the shape of a card. 
     In  FIG. 1 , each configuration has been explained as related to recording and reproduction utilizing holography, but the same configurations are of course adaptable to recording and reproduction of BDs and HD-DVDs. 
     The optical information recording and reproducing device or the optical information reproducing device according to the present invention which device utilizes holography in recording and reproducing signals and also uses BDs, HD-DVDs, and other optical disks as recording or reproducing media is not limited to the optical system configurations shown in  FIG. 6  and  FIG. 8 , but may as well take such optical system configurations as shown in  FIG. 9  and  FIG. 10 , for example. Detailed explanation is omitted here about the optical system configuration as it is based on the  FIG. 4  about which explanation was already made, but  FIG. 9  illustrates the state that the light beam outputted from the laser light source  201  is split into the signal light beam and the reference light beam by means of the polarization beam splitter  205 , with the signals being recorded on the optical information recording medium  1  based on holography. Also,  FIG. 10(   a ) illustrates the state that the optical information recording medium  1  is cured by the light beam outputted from the laser light source  331  which emits a light beam of lower coherence that the laser light source  201 ;  FIG. 10(   b ) likewise indicates the state that recording or reproduction of information is made on the optical disk  101  such as a BD or a HD-DVD. 
     In the configurations in  FIG. 6  and  FIG. 8  above-mentioned, the objective lens used to collect light beams on the optical disk  101  in recording or reproducing information on the optical disks such as BDs and HD-DVDs has been the objective lens  408  which is different from the objective lens  210  used for recording or reproducing signals based on holography. On the other hand, the examples shown in  FIG. 9  and  FIG. 10  are characterized in that the objective lens  210  used for recording or reproducing of signals based on holography is also used for collecting the light beams on BDs, HD-DVDs, and other optical disks  101 . 
     To realize the above feature, the present example provides the holder  413  having the aperture  412  and the lens  215  and also provides a mechanism which enables displacement of the position of the holder  413  along the movable direction  414 . By adoption of such mechanism, change-over is possible for the light beam either to go through the lens  215  or not to go through the lens  215  when the light beam reflected at the mirror  214  is transmitted through the holder  414 . In other words, when the light beam reflected at the mirror  214  is incident on the objective lens  210 , selection is available for the light beam either to be transmitted through the lens  215  and made to focus once on the back focus plane of the objective lens  210  as shown in  FIG. 10(   a ), or to be made incident on the objective lens  210  directly without going via the lens  215  as shown in  FIG. 10(   b ). Additionally in the present example, the objective lens  210  has a mechanism by which the position of the lens  210  is made adjustable along the movable direction  220 . Therefore, the objective lens  210  is adjustable in its position so that the light beam incident on the entrance pupil of the objective lens  210  may be incident fittingly on a desired position. 
     The present example also provides the beam expander  405  so that the light beam  212  proceeding to the mirror  214  after reflected at the polarization beam splitter  205  may be given a desired diameter of luminous flux. More specifically, the beam expander  405  is so designed that the luminous flux of the light beam incident on the objective lens  210  may have a diameter equivalent to a numerical aperture of 0.85 when the system is in charge of recording or reproduction of BDs. Since displacing the position of the lens in the beam expander  405  enables adjustment in convergence, divergence, and parallelism, it is made also possible to adjust correction amount of spherical aberration. 
     And in  FIG. 7 , shown is the operational flow of recording and reproduction in the optical information recording and reproducing device  10 . Explanation is made in particular about the flow of recording and reproduction utilizing holography. 
       FIG. 7(   a ) indicates the operational flow starting from immediately after the optical information recording medium  1  is inserted in the optical information recording and reproducing device  10  till the preparation for recording and reproduction is finished.  FIG. 7(   b ) covers the operational flow from the state of the preparation finished till recording of information done on the optical information recording medium  1 . And,  FIG. 7(   c ) shows the operational flow from the state of the preparation finished till reproduction of information recorded in the optical information recording medium  1 . 
     As shown in  FIG. 7(   a ), when a recording medium is inserted, the optical information recording and reproducing device  10  conducts disk identification to find out, for example, whether or not the inserted disk is the medium on which digital information is recorded or reproduced by utilization of holography. 
     If the disk is identified, as a result of disk identification, to be an optical information recording medium used to record or reproduce digital information by utilizing holography, the optical information recording and reproducing device  10  is to read out the control data contained in the optical information recording medium to acquire, for example, the information on the optical information recording medium and various set-up conditions applicable to recording or reproducing operation. 
     After readout of the control data, various adjustments corresponding to the control data and the learning and processing relating to the pickup  11  are undertaken inducing the optical information recording and reproducing device  10  into a ready mode for recording and reproduction. 
     The operational flow from the ready mode till data recording is as shown in  FIG. 7(   b ). In the first place, the data to be is received, and the information according to that data is to be supplied to the spatial light modulator in the pickup  11 . 
     Then, in order that high quality information can be recorded, various matters of learning are processed in advance according to need; and while seek operations and address reproductions are being repeated, the pickup  11  and the disk cure optical system  13  are to be arranged in certain proper positions in relation to the optical information recording medium. 
     Following the above, required ambits are to be precured with the light beam outputted from the disk cure optical system  13 , and recording of the data is made by using the reference light beam and the signal light beam emitted from the pickup  11 . 
     After recording of the data, such data maybe verified as needed, and post-curing is conducted with the light beam outputted from the disk cure optical system  13 . 
       FIG. 7(   c ) shows the operational flow from the ready mode till reproduction of the recorded data. In order to realize reproduction of high-quality information from the optical information recording medium, various matters of learning are processed in advance according to need; and while seek operations and address reproductions are being repeated, the pickup  11  and the phase conjugate optical system  12  are to be arranged in certain proper positions in relation to the optical information recording medium. 
     Subsequently, the reference light beam is emitted from the pickup  11  to read out the information recorded in the optical information recording medium. 
     While we have shown and described several embodiments in accordance with our invention, it should be understood that disclosed embodiments are susceptible of changes and modifications without departing from the scope of the invention. Therefore, we do not intend to be bound by the details shown and described herein but intend to cover all such changes and modifications that fall within the ambit of the appended claims.