WO2020008496A1

WO2020008496A1 - Hologram recording device, hologram reproducing device, hologram recording method, and hologram reproducing method

Info

Publication number: WO2020008496A1
Application number: PCT/JP2018/025050
Authority: WO
Inventors: 利樹石井
Original assignee: 株式会社日立製作所
Priority date: 2018-07-02
Filing date: 2018-07-02
Publication date: 2020-01-09

Abstract

The purpose of the present invention is to improve recording density with a simple configuration in the art of hologram recording. Provided is a hologram recording device for recording information by emitting signal light and reference light onto a recording medium, and is characterized by having: a light source unit that emits a light beam; an optical separation unit that separates the light beam into the signal light and the reference light; a spatial light modulation unit that modulates the signal light; an objective lens through which the signal light and the reference light pass; a position control unit that controls the positions of a signal light emission region, that is, an emission region of the signal light on the objective lens, and a reference light emission region, that is, an emission region of the reference light on the objective lens; and an angle control unit that controls the incident angle of the reference light on the recording medium, wherein the angle control unit causes the reference light to be incident on the recording medium at multiple different angles by changing the incident angle while the signal light that has passed through the signal light emission region, the position of which has been fixed by the position control unit, is incident on the recording medium.

Description

Hologram recording device, hologram reproducing device, hologram recording method, and hologram reproducing method

The present invention relates to a hologram recording device, a hologram reproducing device, a hologram recording method, and a hologram reproducing method.

ホログラム Hologram recording technology that can increase the recording capacity is attracting attention.

Patent Document 1 discloses a technique relating to dynamic aperture holography. Paragraph 0053 of the document states, “Operation 301 passes the first signal beam 243A through the objective lens 245 of the first embodiment, and then projects the first signal beam 243A onto the photosensitive recording medium 258 with the first signal beam angle aperture 270A. Including. " In addition, the paragraph 0055 states that “the first reference beam 233A is projected through the objective lens 245 of the first embodiment onto the photosensitive recording medium 258 with the first reference beam angle aperture 276A. The first signal beam 243A and The first reference beams 233A interfere with each other to generate a first interference pattern 248A, and a portion of the first interference pattern 248A present in the photosensitive recording layer 260 of the recording medium 258 is partially embedded in the photosensitive recording medium 258. It is recorded as the first hologram 249A. "

Japanese Unexamined Patent Publication No. 2016-510931

In hologram recording technology, it is expected to increase the number of multiplexes and increase the recording density without complicating the apparatus.

In the technique according to Patent Literature 1, since the size of the signal light is changed to increase the number of multiplexes, the page format of the signal included in the signal light changes, and the load of signal processing increases.

The present invention has been made in view of the above points, and has as its object to improve the recording density with a simple configuration in a hologram recording technique.

Although the present application includes a plurality of means for solving the above-mentioned problems, examples thereof are as follows.

In order to solve the above problem, a hologram recording device according to one embodiment of the present invention is a hologram recording device that records information by irradiating a recording medium with signal light and reference light, and a light source unit that emits a light beam An optical separation unit that separates the light beam into the signal light and the reference light, a spatial light modulation unit that modulates the signal light, an objective lens that transmits the signal light and the reference light, A position control unit configured to change a position of a signal light irradiation area that is an irradiation area of the signal light on the objective lens and a reference light irradiation area that is an irradiation area of the reference light on the objective lens; An angle control unit that controls an incident angle with respect to the recording medium, wherein the signal light transmitted through the signal light irradiation area whose position is fixed by the position control unit is transmitted to the recording medium. Before the incident By changing the angle of incidence, and wherein the incident the reference light beam onto the recording medium at a plurality of different angles.

According to the present invention, in the hologram recording technology, the recording density can be improved with a simple configuration.

The problems, configurations, and effects other than those described above will be apparent from the following description of the embodiments.

FIG. 3 is a diagram illustrating an example of functional blocks of the hologram recording / reproducing device. FIG. 2 is a diagram (part 1) illustrating a configuration example of a pickup according to the first embodiment. FIG. 3 is a diagram (part 2) illustrating a configuration example of a pickup according to the first embodiment. FIG. 3 is a diagram illustrating an example of an arrangement of signal light and reference light in the objective lens according to the first embodiment. FIG. 3 is a block diagram of a signal generation circuit of the hologram recording / reproducing device. FIG. 3 is a block diagram of a signal processing circuit of the hologram recording / reproducing apparatus. 4 is a flowchart illustrating an example of preparation for recording processing and reproduction processing in the hologram recording / reproduction device. 9 is a flowchart illustrating an example of a recording process. It is a flow chart which shows an example of reproduction processing. It is a flowchart which shows an example of a signal generation process. It is a flowchart which shows an example of a signal reproduction process. 5 is a flowchart illustrating an example of a data recording process according to the first embodiment. It is a figure showing the example of composition of the pickup in a 2nd embodiment. It is a figure showing an example of arrangement of signal light and reference light in the objective lens of a 2nd embodiment. 9 is a flowchart illustrating an example of a data recording process according to the second embodiment. It is a figure showing the example of composition of the pickup in a 3rd embodiment. It is a figure showing the example of composition of the pickup in the modification of a 3rd embodiment. FIG. 3 is a diagram illustrating a configuration example of a pickup and a recording principle. FIG. 3 is a diagram illustrating a configuration example of a pickup and a principle of reproduction.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an example of functional blocks of the hologram recording / reproducing device 10. The hologram recording / reproducing apparatus 10 is a recording / reproducing apparatus for the hologram recording medium 1 for recording and / or reproducing digital information using holography. The hologram recording / reproducing device 10 is communicably connected to an external control device 91 via an input / output control circuit 90.

When recording information, the hologram recording / reproducing apparatus 10 receives a signal (user data) indicating information to be recorded from the external control device 91 via the input / output control circuit 90. When reproducing information, the hologram recording / reproduction device 10 transmits a signal indicating the reproduced information to the external control device 91 via the input / output control circuit 90.

The hologram recording and reproducing apparatus 10 includes a pickup 11, a reproducing reference light optical system 12, a cure optical system 13, a disk rotation angle detecting optical system 14, a rotation motor 50, an access control circuit 81, and a light source driving circuit. 82, a servo signal generation circuit 83, a servo control circuit 84, a signal processing circuit 85, a signal generation circuit 86, a shutter control circuit 87, a disk rotation motor control circuit 88, a controller 89, and an input / output control circuit 90.

The pickup 11 irradiates reference light and signal light obtained from the light generated by the light source drive circuit 82 onto the optical recording medium to generate a hologram, and plays a role of recording digital information on the recording medium. The information to be recorded is sent to a spatial light modulator (described later) in the pickup 11 by the controller 89 via the signal generation circuit 86 and modulated.

(4) The pickup 11 causes the reference light generated using the reproduction reference light optical system 12 to enter the hologram recording medium 1 in a direction opposite to the direction at the time of recording. The pickup 11 detects the reference light for reproduction by a light detection unit described later, and reproduces a signal by the signal processing circuit 85.

The irradiation time of the reference light and the signal light irradiated on the hologram recording medium 1 can be adjusted by controlling the opening and closing time of the shutter in the pickup 11 by the controller 89 via the shutter control circuit 87.

The 光学 cure optical system 13 has a role of generating a light beam used for pre-curing and post-curing of the hologram recording medium 1. Precuring is a pre-process of irradiating a predetermined light beam before irradiating a desired position with reference light and signal light when recording information at a desired position in the hologram recording medium 1. The post cure is a post-process in which information is recorded at a desired position in the hologram recording medium 1 and then a predetermined light beam is irradiated to make it impossible to additionally record at the desired position.

The disk rotation angle detecting optical system 14 is used to detect the rotation angle of the hologram recording medium 1. The hologram recording medium 1 is configured to be rotatable by a rotation motor 50. When adjusting the hologram recording medium 1 to a desired rotation angle, the disk rotation angle detecting optical system 14 detects a signal corresponding to the rotation angle. Thereafter, under the control of the controller 89, the rotation angle can be adjusted via the disk rotation motor control circuit 88 using the detected signal.

Further, under the control of the controller 89, a predetermined light source drive current is supplied from the light source drive circuit 82 to the light sources in the pickup 11, the cure optical system 13, and the optical system 14 for detecting the rotation angle of the disk. Can emit a light beam. The pickup 11, the cure optical system 13, and the disk rotation angle detection optical system 14 may be simplified by combining two or more optical system configurations into one optical system configuration.

The pickup 11 and the cure optical system 13 are provided with a mechanism capable of sliding the positions of the hologram recording medium 1 in the radial direction, and the position is controlled through the access control circuit 81 under the control of the controller 89.

FIG. 15 is a diagram showing a configuration example of the pickup 11 and a recording principle. The light beam emitted from the light source 301 passes through the collimator lens 302 and enters the shutter 303. When the shutter 303 is open, the light beam passes through the shutter 303 and then enters the optical element 304. The optical element 304 is, for example, a half-wave plate, and controls the polarization direction such that the light amount ratio between the p-polarized light and the s-polarized light becomes a predetermined desired ratio.

The light beam whose polarization direction has been controlled by the optical element 304 then enters the optical separation unit 305. The optical separation unit 305 is, for example, a PBS (Polarizing Beam Splitter) prism.

The light beam transmitted through the optical separation unit 305 functions as a signal light 306. After the light beam diameter is expanded by a beam expander 308, the light beam passes through a phase mask 309, a relay lens 310, and a PBS prism 311 to generate spatial light. The light enters the modulator 312.

The spatial light modulator 312 adds information to the signal light 306 and emits it. The emitted signal light 306 is reflected by the PBS prism 311 and propagates through the relay lens 313 and the spatial filter 314. After that, the signal light 306 is focused on the hologram recording medium 1 by the objective lens 315.

On the other hand, the light beam reflected by the optical separation unit 305 functions as the reference light 307, and after being set to a predetermined polarization direction by the polarization direction conversion element 316 according to recording or reproduction, the mirror 317 and the mirror 318 are turned on. The light then enters the angle control unit 319. As the angle control unit 319, for example, a galvanomirror can be used. The angle control unit 319 can adjust the angle by the actuator 320. That is, the incident angle of the reference beam 307 that is transmitted through the lens 321, reflected by the mirror 322, transmitted through the objective lens 315, and then incident on the hologram recording medium 1 can be controlled to a desired angle.

In order to control the incident angle of the reference light 307, an element that converts the wavefront of the reference light 307 may be used in the angle control unit 319 instead of the galvanomirror.

In this way, by causing the signal light 306 and the reference light 307 to be incident on the hologram recording medium 1 so as to overlap each other, an interference fringe pattern is formed inside the hologram recording medium 1. By writing the interference fringe pattern on the hologram recording medium 1, information is recorded as a hologram.

Note that the angle control unit 319 can change the incident angle of the reference beam 307 incident on the hologram recording medium 1, so that recording by angle multiplexing is possible.

Hereinafter, a hologram recorded in the same area on the hologram recording medium 1 at a different angle of the reference light will be described as a hologram corresponding to a certain angle, and a set of pages recorded by angle multiplexing in the same area. Will be described as a book.

FIG. 16 is a diagram showing a configuration example of the pickup 11 and a principle of reproduction. This drawing is a diagram for explaining the principle of reproduction in the pickup 11 having the same configuration as that of FIG. When information recorded on the hologram recording medium 1 is reproduced, a reference beam is made incident on the hologram recording medium 1, and a light beam transmitted through the hologram recording medium 1 is reflected by an actuator 323 to an angle control unit 324 whose angle can be adjusted. Generates a reference light for reproduction.

In other words, the reference light for reproduction is obtained by irradiating the reference light from the surface of the hologram recording medium 1 opposite to the surface irradiated with the reference light during recording. That is, the hologram recording medium 1 is irradiated with the reference light in a direction opposite to that of the recording.

The reference light 326 reproduced by the reference light for reproduction propagates through the objective lens 315, the relay lens 313, and the spatial filter 314. After that, the reference light 326 passes through the PBS prism 311 and enters the light detection unit 325. When the light detection unit 325 detects the reference light 326, the signal recorded by the signal processing circuit 85 can be reproduced as described above.

As the light detection unit 325, for example, an imaging element such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor can be used, but the element is not limited as long as page data can be reproduced. .

(4) In order to record information on the hologram recording medium 1, further improvement in recording density is desired. Therefore, the present invention improves the recording density by using the following representative means.

FIG. 2 is a diagram (part 1) illustrating a configuration example of the pickup 11 in the first embodiment. Hereinafter, points different from the configuration example of the pickup 11 illustrated in FIG. 15 will be described. In the first embodiment, a lens 501 having a larger aperture is used instead of the lens 321 shown in FIG. In the first embodiment, a mirror 502 extending in the scanning direction of the reference light is used instead of the mirror 322 shown in FIG. With this configuration, the incident angle of the reference light incident on the hologram recording medium 1 can be changed more greatly than in the case shown in FIG.

The reference light shown in FIG. 2 is transmitted through the left side of the objective lens 315. The signal light shown in FIG. 2 is transmitted through the right side of the objective lens 315.

FIG. 3 is a diagram (part 2) illustrating a configuration example of the pickup 11 in the first embodiment. This figure shows an example in which the control of the signal light and the reference light is changed in the configuration shown in FIG. As a result, the reference light shown in FIG. 3 passes through the right side of the objective lens 315. The signal light shown in FIG. 3 is transmitted through the left side of the objective lens 315.

照射 By changing the angle of the angle control unit 319, the irradiation position of the reference light on the mirror 502 can be changed. By changing the irradiation position of the reference light, the incident angle of the reference light incident on the hologram recording medium 1 can be changed.

In the present embodiment, the controller 89 functions as a position control unit that controls the change of the irradiation position of the reference light. In the configuration examples shown in FIGS. 2 and 3, the incident angle of the reference light incident on the hologram recording medium 1 is inverted.

{Circle around (5)} The controller 89 changes the area of the signal light to be modulated by the spatial light modulator 312, and changes the irradiation position of the signal light to the mirror 502. That is, the controller 89 also functions as a position control unit that controls the change of the irradiation position of the signal light. In the configuration examples shown in FIGS. 2 and 3, the incident angle of the signal light incident on the hologram recording medium 1 is inverted by changing the irradiation position.

In the configuration examples shown in FIGS. 2 and 3, the signal light modulated by the spatial light modulator 312 and the reference light reflected by the mirror 502 are guided coaxially and transmitted through the objective lens 315.

In addition, in order to reproduce the hologram recording medium 1 on which information is recorded by the hologram in the present embodiment, the hologram recording medium 1 is referred to in the opposite direction to the recording as in the case described with reference to FIG. Irradiate light. In this case, the controller 89 changes the position of the reference light irradiation area as in the case of recording.

The setting information such as the timing and the incident angle regarding the change of the position of the reference light irradiation area is predetermined. For example, the controller 89 may specify the setting information by referring to the management information of the hologram recording medium 1. Alternatively, the controller 89 may refer to setting information defined by a standard defined for recording and reproduction using a hologram.

FIG. 4 is a diagram illustrating an example of an arrangement of signal light and reference light in the objective lens 315 of the first embodiment. The upper part of FIG. 4 is a diagram showing the arrangement of the signal light and the reference light when the objective lens 315 shown in FIGS. 2 and 3 is viewed from the signal light irradiation direction (that is, the optical axis direction of the objective lens 315). . That is, the upper part of FIG. 4 shows a state in which the objective lens 315 is viewed from the upper side to the lower side of the paper of FIGS. 2 and 3.

The lower part of FIG. 4 shows the hologram recording medium 1, the signal light, and the reference light from the near side to the far side of the paper surface of FIGS. 2 and 3 (that is, from the same direction as FIGS. 2 and 3). Indicates the status. That is, the lower part of FIG. 4 illustrates a state in which the signal light and the reference light applied to the hologram recording medium 1 are viewed from a direction orthogonal to a plane including the signal light and the reference light transmitted through the objective lens 315. It can be said that there is. First, the upper and lower views on the left side of FIG. 4 will be described.

(4) As shown in the upper left of FIG. 4, the objective lens 315 and the mirror 502 are arranged so that the rectangular mirror 502 can be seen in the effective diameter 101 when the objective lens 315 is viewed from the optical axis direction. 4 shows the rear surface of the mirror 502, and does not show the reflection surface on the rear side of the rear surface. When the reference light is scanned by the control of the angle control unit 319, the position of the reference light changes on a line connecting the

points

503a and 504a on the reflection surface of the mirror 502. When the position of the reference light on the reflecting surface of the mirror 502 changes, the position of the reference light reflected on the reflecting surface on the objective lens 315 changes. The irradiation area of the reference light on the objective lens 315 is defined as a reference light irradiation area.

4 As shown in the lower left side of FIG. 4, the scanning of the reference light changes the incident angle of the reference light on the hologram recording medium 1 from the innermost angle 505a to the outermost angle 506a.

{Circle around (4)} The signal light is arranged in a region 507a shown on the upper left side of FIG. The irradiation area of the signal light on the objective lens 315 is defined as the signal light irradiation area. The signal light is emitted toward the objective lens 315 from the rear side of the mirror 502. That is, the signal light is not reflected on the reflection surface of the mirror 502.

(4) When the signal light is applied to the inside of the effective diameter 101 of the objective lens 315, the signal light is not applied to the shadowed area of the mirror 502. Therefore, the spatial light modulator 312 includes information in the signal light irradiated on the focal plane of the objective lens 315 excluding a region that is a shadow of the mirror 502. As shown on the lower left side of FIG. 4, the incident angle of the signal light on the hologram recording medium 1 is in a range from the innermost angle 508a to the outermost angle 509a.

角度 Angle multiplex recording is performed by changing the incident angle of the reference light from the innermost angle 505a to the outermost angle 506a. During that time, the position of the signal light irradiation area 507a is fixed. That is, while the signal light transmitted through the signal light irradiation area 507a whose position is fixed is incident on the recording medium 1, the angle control unit 319 changes the incident angle of the reference light. Thereby, the reference light is incident on the recording medium 1 at a plurality of different angles, and angle multiplex recording is performed.

(4) After that, the controller 89 reverses the arrangement of the signal light and the reference light. The result of reversing the arrangement will be described with reference to the upper and lower diagrams on the right side of FIG.

4 As shown on the upper right side of FIG. 4, the position of the reference light changes on the line connecting the

points

503b and 504b on the reflection surface of the mirror 502 under the control of the angle controller 319. Thereby, as shown in the lower right side of FIG. 4, the incident angle of the reference light on the hologram recording medium 1 changes from the innermost angle 505b to the outermost angle 506b.

The signal light is arranged in an area 507b shown on the upper right side in FIG. The incident angle of the signal light on the hologram recording medium 1 ranges from the innermost angle 508b to the outermost angle 509b. While the signal light transmitted through the signal light irradiation area 507b having a fixed position and size is incident on the recording medium 1, the angle control unit 319 changes the incident angle of the reference light from the innermost angle 505b to the outermost angle 506b. As a result, angle multiplex recording is performed on the signal light irradiated to the signal irradiation area 507b.

As described above, in the present embodiment, the positions of the signal light irradiation area and the reference light irradiation area are switched under the control of the controller 89. It is desirable that the size of the signal light irradiation region be constant before and after the position of the signal light irradiation region and the reference light irradiation region are changed. As a result, the magnitude of the signal light on the hologram recording medium 1 becomes constant. With this configuration, it is not necessary to change the page format, and it is possible to increase the recording density without increasing the load of signal processing.

Additionally, the signal light irradiation region and the reference light irradiation region are located at positions facing each other with the optical axis of the objective lens 315 as the center, as shown in the upper two figures of FIG. In addition, as an example, the shape of the signal light irradiation region is a line-symmetric shape with respect to a certain straight line passing through the optical axis of the objective lens 315.

When the positions are changed, it is preferable that the positions of the signal light irradiation region and the reference light irradiation region are changed so as to rotate around the optical axis of the objective lens 315. As a result, the effect of peristrographic multiplexing is obtained, and the recording density can be increased.

(4) The width 509 of the mirror 502 is a size that includes most (for example, 95%) of the reference light applied to the mirror 502. That is, the width 509 of the mirror 502 is configured to substantially include the reference light. The irradiation range of the reference light with respect to the mirror 502 is maximized when the incident angle is maximized. That is, the width 509 of the mirror 502 is large enough to substantially reflect the reference light when the incident angle is the maximum.

(4) Here, the focusing position of the reference light is considered. It is preferable that the reference light be condensed at any part on the mirror 502 and then converted into parallel light by the objective lens 315. When irradiating the reference light to the mirror 502 under the control of the angle control unit 319, when the reference light is irradiated so as to be condensed at a position closer to the left or right on the mirror 502, the light at the converging position is not At the end of the mirror 502, the irradiation range of the reference light becomes the largest.

For example, when the reference light is condensed at the position of the point 504a in the upper left diagram of FIG. 4, the irradiation range of the reference light becomes the largest at the point 504b in the upper right diagram of FIG. On the other hand, when the reference light is condensed at the center of the mirror 502, the irradiation range of the reference light is the largest at both ends of the mirror 502 (that is, at the

points

504a and 504b). It becomes smaller than the irradiation range at the point 504b when the condensing position is the point 504a.

中央 The center of the mirror 502 indicates a position on the mirror 502 where the reference light reflected by the mirror 502 is irradiated near the center of the objective lens 315.

As described above, since the signal light is not irradiated to the shadow area of the mirror 502, it is desirable to make the mirror 502 thinner when the signal light contains a lot of information. Therefore, in the present embodiment, it is desirable to design the reference light condensing position at the center of the mirror 502. As a result, a portion of the mirror 502 that becomes a shadow can be reduced, so that a reduction in the page data capacity of the signal light can be suppressed.

FIG. 5 is a block diagram of the signal generating circuit 86 of the hologram recording / reproducing apparatus 10. When the user data is input from the external control device 91 to the input / output control circuit 90, the input / output control circuit 90 notifies the controller 89 that the input of the user data has started. The controller 89 receives the notification and instructs the signal generation circuit 86 to record and process one page of data input from the input / output control circuit 90.

The processing command from the controller 89 is sent to the sub-controller 701 in the signal generation circuit 86 via the control line 708. Upon receiving the notification, the sub-controller 701 controls via the control line 708 such that the signal processing circuits 85 operate in parallel. Under the control of the sub-controller 701, the memory control circuit 703 controls to store user data input from the input / output control circuit 90 via the data line 709 in the memory 702.

When the user data stored in the memory 702 reaches a certain amount, a CRC (Cyclic Redundancy Check) operation circuit 704 controls the user data to be converted into a CRC. Next, a scramble circuit 705 performs scrambling to add a pseudo-random number data sequence to the CRC-converted user data, and an error correction coding circuit 706 controls to perform error correction coding to add a parity data sequence. Next, the pickup (spatial light modulator) interface circuit 707 reads the error-corrected coded data from the memory 702 in the arrangement order of the two-dimensional data on the spatial light modulator 312, and specifies a marker that is a reference at the time of reproduction. Add. After that, the two-dimensional data is transmitted to the spatial light modulator 312 in the pickup 11.

FIG. 6 is a block diagram of the signal processing circuit 85 of the hologram recording / reproducing apparatus 10. When the light detector 325 in the pickup 11 detects image data included in the reference light for reproduction, the controller 89 instructs the signal processing circuit 85 to reproduce one page of image data input from the pickup 11. . The processing command from the controller 89 is notified to the sub-controller 801 in the signal processing circuit 85 via the control line 811.

(4) Upon receiving the notification, the sub-controller 801 controls each signal processing circuit 85 via the control line 811 so that the signal processing circuits 85 operate in parallel. First, the sub-controller 801 controls to store image data input from the pickup 11 via the pickup (photodetector) interface circuit 810 in the memory 802 via the control line 811.

When the image data stored in the memory 802 reaches a certain fixed amount, the sub-controller 801 performs control to detect a marker from the image data stored in the memory 802 and extract a valid data range by using an image position detection circuit. 809 is performed. Next, using the detected marker, the image distortion correction circuit 808 performs distortion correction such as image tilt, magnification, and distortion, and performs control to convert the image data into a desired two-dimensional data size.

Next, a binarization circuit 807 performs a binarization process of determining each bit data of a plurality of bits forming two-dimensional data in two-dimensional data whose size has been converted as “0” or “1”. An operation of storing data in the order of reproduction data output on the 802 is performed. Next, an error included in each data string is corrected by an error correction circuit 806, and a scramble descramble circuit 805 descrambles the pseudo random number data string. Thereafter, the CRC calculation circuit 804 checks whether or not the user data on the memory 802 contains an error. Thereafter, the user data is transmitted from the memory 802 to the input / output control circuit 90.

FIG. 7A is a flowchart illustrating an example of preparation for recording processing and reproduction processing in the hologram recording / reproduction device 10. The following processing is executed in the hologram recording / reproducing apparatus 10 under the control of the controller 89.

First, when detecting the installation of the disk, the hologram recording / reproduction device 10 determines whether the inserted disk is the hologram recording medium 1 for recording or reproducing digital information using holography (step S701). ).

Next, the hologram recording / reproducing apparatus 10 reads the disk information (control data) included in the hologram recording medium 1 (Step S702). The hologram recording / reproducing apparatus 10 acquires, for example, information on the hologram recording medium 1 itself and information on various setting conditions during recording or reproduction.

Next, the hologram recording / reproducing apparatus 10 performs various adjustments according to the control data and learning processing related to the pickup 11 (step S703). After that, the hologram recording / reproducing apparatus 10 completes preparations for recording or reproduction (Ready state) (step S704). Thereafter, in the hologram recording / reproducing apparatus 10, the processing of this flowchart ends.

FIG. 7B is a flowchart illustrating an example of the recording process. The following processing is executed in the hologram recording / reproducing apparatus 10 under the control of the controller 89, similarly to the processing shown in FIG. This process is executed after the completion of the preparation process shown in FIG.

First, the hologram recording / reproducing apparatus 10 receives recording data from the external control device 91 (Step S711). The received recording data is then sent to the spatial light modulator 312 in the pickup 11.

Next, the hologram recording / reproducing apparatus 10 executes a learning process for recording (step S712). Specifically, the hologram recording / reproducing apparatus 10 performs various recording learning processes as needed in order to record high-quality information on the hologram recording medium 1. The recording learning process includes, for example, a process of optimizing the power of the light source 301 and a process of optimizing the exposure time by the shutter 303.

Next, the hologram recording / reproducing device 10 performs a seek process (Step S713). Specifically, the hologram recording / reproducing apparatus 10 controls the access control circuit 81 to position the pickup 11 and the cure optical system 13 at predetermined positions on the hologram recording medium 1. When the hologram recording medium 1 has the address information, the address information is reproduced and it is confirmed whether or not the hologram recording medium 1 is positioned at a target position. If the position is not positioned at the target position, the amount of deviation from the target position is calculated, and the operation of positioning again is repeated.

Next, the hologram recording / reproducing apparatus 10 performs a precure process (step S714). Specifically, the hologram recording / reproducing apparatus 10 precurs a predetermined area using a light beam emitted from the cure optical system 13.

Next, the hologram recording / reproducing device 10 performs a data recording process (Step S715). This processing will be described later in detail.

Next, the hologram recording / reproducing device 10 performs a post cure process (step S716). Specifically, the hologram recording / reproducing apparatus 10 performs post cure using a light beam emitted from the cure optical system 13. At that time, data can be verified as needed. Thereafter, the hologram recording medium 1 ends the processing of this flowchart.

FIG. 7C is a flowchart illustrating an example of the reproduction process. The following processing is executed under the control of the controller 89 in the hologram recording / reproducing apparatus 10 as in the processing shown in FIGS. 7A and 7B. This process is executed after the completion of the preparation process shown in FIG.

First, the hologram recording / reproducing device 10 performs a seek process (Step S721). More specifically, the hologram recording / reproducing apparatus 10 controls the access control circuit 81 to position the pickup 11 and the reference light beam system for reproduction 12 at predetermined positions on the hologram recording medium 1. When the hologram recording medium 1 has the address information, the hologram recording / reproducing apparatus 10 reproduces the address information and checks whether the hologram recording medium 1 is positioned at a target position. If the position is not positioned at the target position, the amount of deviation from the target position is calculated, and the operation of positioning again is repeated.

Next, the hologram recording / reproducing device 10 performs a data reproducing process (Step S722). Specifically, the hologram recording / reproducing apparatus 10 emits reference light from the pickup 11 and detects reference light for reproduction. The hologram recording / reproducing apparatus 10 reads information recorded on the hologram recording medium 1 from the detected reproduction reference light.

Next, the hologram recording / reproducing device 10 transmits the reproduced data (Step S723). Specifically, the hologram recording / reproducing device 10 transmits the read information to the external control device 91. Thereafter, the hologram recording medium 1 ends the processing of this flowchart.

FIG. 8A is a flowchart illustrating an example of the signal generation process. This figure shows an example of processing in the signal generation circuit 86 after the data reception processing in step S711 in FIG. 7B until the received data is converted into two-dimensional data output from the spatial light modulator 312. It is shown.

処理 The processing in step S801 is the same as the processing in step S711, and a description thereof will not be repeated. The received data is notified to the signal generation circuit 86 via the input / output control circuit 90.

Next, the signal generation circuit 86 performs a CRC adding process (step S802). Specifically, the signal generation circuit 86 divides the received data into a plurality of data strings, and converts each data string into a CRC so that an error can be detected during reproduction.

Next, the signal generation circuit 86 converts the data into scrambled data (step S803). Specifically, the signal generation circuit 86 adds a pseudo-random number data sequence to the data sequence for the purpose of making the number of on-pixels and the number of off-pixels of the CRC-converted data substantially equal, and preventing the same pattern from being repeated.

Next, the signal generation circuit 86 performs error correction coding (step S804). Specifically, the signal generation circuit 86 performs error correction coding such as Reed-Solomon code so that error correction can be performed during data reproduction.

Next, the signal generation circuit 86 performs two-dimensional data conversion (step S805). Specifically, the signal generation circuit 86 converts the data sequence into M × N two-dimensional data, and repeats the conversion for one page, thereby generating one page of two-dimensional data.

Next, the signal generation circuit 86 performs marker addition (step S806). More specifically, the signal generation circuit 86 adds, to the two-dimensional data, a marker that is used as a reference in image position detection during reproduction and image distortion correction.

Next, the signal generation circuit 86 performs pattern transfer to the spatial light modulator 312 (Step S807). The signal generation circuit 86 transmits the two-dimensional data with the marker added to the spatial light modulator 312. Thereafter, the processing of this flowchart ends.

FIG. 8B is a flowchart illustrating an example of the signal reproduction process. This figure shows an example of the processing performed by the signal processing circuit 85 after the two-dimensional data is detected by the light detection unit 325 in step S722 in FIG. 7C and before the reproduction data is transmitted in step S723. It is shown.

First, the photodetector acquires a reproduced image (step S811). Specifically, the signal processing circuit 85 acquires data detected by the photodetector.

Next, the signal processing circuit 85 detects an image position (step S812). The signal processing circuit 85 detects an image position based on a marker included in the data.

Next, the signal processing circuit 85 performs image distortion correction (step S813). More specifically, the signal processing circuit 85 corrects distortion such as image inclination, magnification, and distortion.

Next, the signal processing circuit 85 performs a binarization process (step S814).

Next, the signal processing circuit 85 removes the marker (Step S815).

Next, the signal processing circuit 85 acquires two-dimensional data (step S816). Specifically, the signal processing circuit 85 acquires one page of two-dimensional data from which the marker has been removed. The signal processing circuit 85 converts the obtained two-dimensional data into a plurality of data strings.

Next, the signal processing circuit 85 performs an error correction process (step S817). The signal processing circuit 85 removes the parity data sequence by performing an error correction process.

Next, the signal processing circuit 85 performs descrambling (step S818).

Next, the signal processing circuit 85 performs error detection (step S819). Specifically, the signal processing circuit 85 performs an error detection process using the CRC and deletes the CRC parity.

Next, the signal processing circuit 85 transmits the reproduced data (step S820). The processing performed in this step is the same as the processing performed in step S723 shown in FIG. Thereafter, the processing of this flowchart ends.

FIG. 9 is a flowchart illustrating an example of a data recording process according to the first embodiment. This figure shows the processing performed in step S715 of FIG. 7B in more detail. The following processing is executed in the hologram recording / reproducing apparatus 10 under the control of the controller 89.

First, the hologram recording / reproducing apparatus 10 positions the hologram recording medium 1 on the first page (Step S901). Specifically, the hologram recording / reproducing apparatus 10 positions the hologram recording medium 1 at the position where the first page is recorded, and controls the angle of the reference light using the angle control unit 319. The angle of the reference light is the angle at which the first page is recorded.

Next, the hologram recording / reproducing apparatus 10 performs page recording (step S902). Specifically, the hologram recording / reproducing apparatus 10 performs page recording by modulating page data using the spatial light modulator 312 and causing the signal light and the reference light to interfere with each other in the hologram recording medium 1.

Next, the hologram recording / reproducing apparatus 10 determines whether or not it is the last angle multiplexing (Step S903). Specifically, the hologram recording / reproducing apparatus 10 determines whether or not the angle of the reference light is the last angle at which angle multiplexing is performed.

If the hologram recording / reproducing device 10 determines that the angle of the reference light is not the last angle (“No” in step S903), the hologram recording / reproducing device 10 changes the angle of the reference light (step S904). Specifically, the hologram recording / reproducing apparatus 10 changes the angle of the reference light to the angle to be recorded next, and performs a page recording process in Step 902.

When the hologram recording / reproducing apparatus 10 determines that the angle of the reference light is the last angle (in the case of “Yes” in step S903), the hologram recording / reproducing apparatus 10 determines whether or not the last perisotropic multiplexing is performed. Is determined (step S905). Specifically, the hologram recording / reproducing apparatus 10 determines whether or not the arrangement of the signal light and the reference light is an arrangement for performing the last peristroic multiplexing.

If the hologram recording / reproducing apparatus 10 determines that the last peristrographic multiplexing is not performed ("No" in step S905), the hologram recording / reproducing apparatus 10 changes the use area of the spatial light modulator 312 (step S906). ). As a result of this processing, the position of the signal light irradiation area on the objective lens 315 is changed.

Next, the hologram recording / reproducing device 10 changes the use area of the reference light (Step S907). As a result of this processing, the position of the reference light irradiation area on the objective lens 315 is changed. After that, the hologram recording / reproduction device 10 shifts the processing to step S902.

When the hologram recording / reproducing apparatus 10 determines that the last peristrographic multiplex is performed (in the case of “Yes” in step S905), the hologram recording / reproducing apparatus 10 determines whether the book recorded in step S902 is the last book. It is determined whether or not it is (step S908). If the hologram recording / reproducing apparatus 10 determines that the book is the last book (“Yes” in step S908), the processing of this flowchart ends. That is, the data recording ends.

If the hologram recording / reproducing apparatus 10 determines that the book is not the last book ("No" in step S908), the hologram recording / reproducing apparatus 10 changes the recording position (step S909). Specifically, the hologram recording / reproducing apparatus 10 changes the recording position of the hologram recording medium 1. Thereafter, the hologram recording medium 1 returns the process to step S902. As a result, the peristrographic multiplexing process is continuously performed.

In the present embodiment, as an example of shortening the time required for changing the angle of the reference light and the time required for changing the book position, an example in which processing is performed in the order of angle multiplexing, peristrographic multiplexing, and book position change Was explained. However, the order of the processes may be changed, or the processes may be performed alternately so that a desired book is finally recorded.

As described above, according to the present embodiment, it is possible to perform recording by combining angle multiplexing and peristlographic multiplexing with a simple configuration. Thereby, the recording density can be improved with a simple configuration.

Hereinafter, a second embodiment will be described. The pickup 11 in the present embodiment has two angle control units that control the incident angle of the reference light. The scanning directions of the reference light by the two angle controllers are orthogonal to each other. Hereinafter, points different from the first embodiment will be described.

FIG. 10 is a diagram illustrating a configuration example of the pickup 11 according to the second embodiment. The pickup 11 shown in FIG. 10 has an angle control unit 1101 instead of the mirror 318, and has a + type mirror 1103 instead of the mirror 502. The pickup 11 shown in FIG. 10 has a polarization direction controller 1104. As an example, a 波長 wavelength plate is used for the polarization direction controller 1104.

The angle control unit 1101 can adjust the angle by the actuator 1102. It is desirable that the angle adjustment direction of the angle control unit 1101 is perpendicular to the angle adjustment direction of the angle control unit 319. That is, the scanning direction of the reference light scanned on the + mirror 1103 by the angle control unit 1101 and the scanning direction of the reference light scanned on the + mirror 1103 by the angle control unit 319 are orthogonal to each other. As an example, a galvanomirror can be used for the angle control unit 1101.

The + type mirror 1103 has a shape of + (plus), and has the same function as that of two mirrors 502 arranged orthogonally. With this configuration, the reference light can be made to enter the hologram recording medium 1 from four different directions. As a result, the reference light can be scanned two-dimensionally. Note that, with the change in the scanning direction of the reference light, the spatial light modulator 312 changes the position of the signal light irradiation region formed by irradiating the objective lens 315 with the signal light.

In the case where information recording processing is performed by the angle multiplexing method, it is desirable to cause the signal light and the reference light to interfere with each other by s-polarization from the viewpoint of maintaining high diffraction efficiency. However, when the arrangement of the signal light and the reference light is rotated by 90 degrees, the s-polarized light becomes the p-polarized light, and the diffraction efficiency decreases. Therefore, the polarization direction control unit 1104 changes the azimuth of the polarization of the signal light 306 and the reference light 307 reflected by the + type mirror 1103, so that the s-polarized light is obtained.

In the present embodiment, the scanning direction of the reference light is changed using two angle control units. However, an element capable of controlling scanning in a two-dimensional direction can be used instead of the angle control unit. is there.

Note that, similarly to the first embodiment, it is necessary to irradiate the hologram recording medium 1 with the reference light at the time of reproduction in a direction opposite to that at the time of recording. Therefore, when the incident angle is changed two-dimensionally during recording, it is necessary to change the scanning direction of the reference light two-dimensionally also during reproduction. For this reason, an angle control unit (not shown) is further added to the angle control unit 324 so that the reference light can be two-dimensionally scanned. Alternatively, an element capable of controlling the reflection direction in two dimensions may be used instead of the angle control unit 324.

FIG. 11 is a diagram illustrating an example of an arrangement of signal light and reference light in the objective lens 315 of the second embodiment. This figure is a diagram showing the arrangement of the signal light and the reference light when the objective lens 315 shown in FIG. 10 is viewed from the signal light irradiation direction (that is, the optical axis direction of the objective lens 315). That is, FIG. 11 shows a state in which the objective lens 315 is viewed from the upper side to the lower side in FIG. It should be noted that the back of the + type mirror 1103 is shown in FIG. The back side of the back is the reflection surface.

において In FIG. 11, a positive mirror 1103 is arranged in the effective diameter 101 of the objective lens 315. When the reference light is scanned two-dimensionally by the angle control unit 1101 and the angle control unit 319, the reference light is reflected by the reflection surface of the + type mirror 1103. The position of the reference light changes on the

lines

1203a, 1203b, 1203c, and 1203d by scanning. It can be said that the + type mirror 1103 is configured to extend along the reference beam scanned orthogonally. Further, according to this configuration, it can be said that the reference light enters the hologram recording medium 1 from four different directions (upward, downward, rightward, and leftward directions shown in FIG. 11).

While the reference light is moving on the line 1203a on the reflection surface, the spatial light modulator 312 arranges the signal light in the area 1204a. Similarly, when the reference light is moving on the line 1203b, the spatial light modulator 312 places the signal light in the region 1204b. When the reference light is moving on the line 1203c, the signal light is arranged in the region 1204c. When the reference light is moving on the line 1203d, the signal light is arranged in the region 1204d. Note that, as an example, even after the position is changed, as shown in FIG. 11, the signal light irradiation region and the reference light irradiation region are at positions facing each other around the optical axis of the objective lens 315. The change in the positions of the signal light irradiation region and the reference light irradiation region is not limited to the order shown in FIG.

角度 Angle multiplexing is possible for each of the four combinations of the signal light and the reference light shown in FIG. In the present embodiment, the arrangement of the signal light and the reference light is rotated by 90 degrees around the optical axis of the objective lens 315. In addition, similarly to the first embodiment, the spatial light modulator 312 records the signal light on the focal plane of the objective lens 315, which is applied to the area excluding the shadow area of the + type mirror 1103. Include information.

Also in this embodiment, since the size of the signal light irradiation area is constant, it is possible to increase the recording density without increasing the signal processing load by fixing the page format.

Additionally, when the numerical aperture of the signal light is large, crosstalk is likely to occur between adjacent peristrographically multiplexed holograms. The signal light irradiation region does not have to have the shape shown in FIG. 11, and may have any shape for suppressing crosstalk.

FIG. 12 is a flowchart illustrating an example of a data recording process according to the second embodiment.

The processing performed in steps S1221 to S1225 is the same as the processing performed in steps S901 to S905 shown in FIG.

In step S1225, when the hologram recording / reproducing apparatus 10 determines that the data is not the last perisotropic multiplexing (“No” in step S1225), the hologram recording / reproducing apparatus 10 changes the polarization of the signal light and the reference light. (Step S1231). Specifically, the hologram recording / reproducing apparatus 10 controls the polarization using the polarization direction control unit 1104 so that the signal light and the reference light become s-polarized light.

Thereafter, the processing performed in steps S1226 to S1229 is the same as the processing performed in steps S906 to S909 in FIG.

In the present embodiment, by changing the arrangement positions of the signal light and the reference light, the effect of peristlographic multiplexing in which recording is performed by rotating the hologram with respect to the optical axis is obtained. it can. In the present embodiment, four multiplexes can be performed.

Also, even if it becomes p-polarized light due to the rotation of the arrangement of the signal light and the reference light, it is changed to s-polarized light. As a result, it is possible to prevent a reduction in diffraction efficiency. In the present flowchart, the positions of the signal light irradiation area and the reproduction light irradiation area are changed after the polarization is changed, but the order of these processes is not limited to the order shown in FIG.

Next, a third embodiment will be described. In the third embodiment, a half beam splitter 1401 is arranged instead of the mirror 502 or the + type mirror 1103. Hereinafter, points different from the first embodiment and the second embodiment will be described.

FIG. 13 is a diagram illustrating a configuration example of the pickup 11 according to the third embodiment. The half beam splitter 1401 reflects the reference light and guides it to the objective lens 315. The half beam splitter 1401 transmits the signal light and guides the signal light to the objective lens 315. That is, the reference light and the signal light are guided coaxially by the half beam splitter 1401 and pass through the objective lens 315.

In the second embodiment, the reference beam is scanned in two orthogonal directions to use the + type mirror 1103. However, since the half beam splitter 1401 has a reflecting surface on the surface, the reference beam can be arbitrarily set. Can be scanned in the direction of. That is, more peristroic multiplexing than four multiplexing is possible.

On the other hand, approximately half of the light amount of the signal light is reflected by the half beam splitter 1401, and approximately half of the reference light is transmitted by the half beam splitter 1401. That is, the light amounts of the signal light and the reference light are reduced by half. In order to maintain the diffraction efficiency of the recorded hologram, it is preferable to double the recording exposure time.

FIG. 14 is a diagram illustrating a configuration example of the pickup 11 according to a modified example of the third embodiment. The pickup 11 according to the present modification includes a reproduction reference optical system 12 including an angle control unit 324 and an actuator 323 for recording information on the hologram recording medium 1, and a reproduction reference optical system including an angle control unit 1505 and an actuator 1504. The optical optical system 12 is included. Further, it further includes a polarization direction controller 1502 for controlling the polarization of the signal light and the reproduction light, and an objective lens 1503.

The reference light transmitted through the half beam splitter 1401 without being reflected is transmitted through the polarization direction control unit 1502 and irradiated on the objective lens 1503. In addition, the signal light reflected without being transmitted through the half beam splitter 1401 is transmitted through the polarization direction controller 1502 and is irradiated on the objective lens 1503. That is, the signal light and the reference light are guided coaxially by the half beam splitter 1401. The signal light and the reference light transmitted through the objective lens 1503 interfere with each other on the hologram recording medium 1501 to form a hologram.

When reproducing the recorded hologram, the reference light for reproduction can be generated by reflecting the reference light to the angle control unit 1505 whose angle can be adjusted by the actuator 1504.

In this modification, the hologram same as that of the hologram recording medium 1 is stored in the hologram recording medium 1501. Thus, the signal light and the reference light that have not been used for recording in the third embodiment can be used for recording on the hologram recording medium 1501, and the light use efficiency is improved.

As described above, by using the hologram recording / reproducing device 10 according to the first to third embodiments, holograms of various angles are multiplexed and stored at predetermined positions of the hologram recording medium 1 by peristlographic multiplexing. can do.

The hologram recording / reproducing apparatus 10 described above is used for recording digital data, and for forming and printing an arbitrary hologram such as a hologram for an ornament or a display, and a hologram of a hologram light guide plate used for a head-mounted display. It can be widely applied.

Although the embodiments and the modified examples according to the present invention have been described above, the present invention is not limited to the above-described example of the embodiment, and includes various modified examples. For example, the example of the above-described embodiment has been described in detail in order to make the present invention easy to understand, and the present invention is not limited to one having all the configurations described here. Further, a part of the configuration of one example of an embodiment can be replaced with the configuration of another example. Further, it is also possible to add another example configuration to the example configuration of one embodiment. Further, for a part of the configuration of an example of each embodiment, another configuration can be added, deleted, or replaced. Further, each of the above-described configurations, functions, processing units, processing means, and the like may be partially or entirely realized by hardware, for example, by designing an integrated circuit. Further, control lines and information lines in the figure indicate those considered to be necessary for the description, and do not necessarily indicate all of them. Almost all configurations may be considered interconnected.

The above configurations, functions, and the like may be realized by software by a processor interpreting and executing a program for realizing each function. Information such as programs for realizing each function should be recorded in a memory, a hard disk, a recording device such as SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD, and read and used. Can be.

The functional configuration of the hologram recording / reproducing apparatus 10 is classified according to main processing contents for easy understanding. The invention of the present application is not limited by the way of classification and names of the components. The configuration of the hologram recording / reproducing apparatus 10 can be further classified into more components according to the processing content. In addition, it can be classified so that one component performs more processing.

1: hologram recording medium, 10: hologram recording / reproducing device, 11: pickup, 12: reference optical system for reproduction, 13: cure optical system, 14: optical system for detecting disk rotation angle, 50: rotation motor, 81: access Control circuit, 82: light source drive circuit, 83: servo signal generation circuit, 84: servo control circuit, 85: signal processing circuit, 86: signal generation circuit, 87: shutter control circuit, 88: disk rotation motor control circuit, 89: Controller, 90: input / output control circuit, 91: external control device, 101: effective diameter, 301: light source, 302: collimating lens, 303: shutter, 304: optical element, 305: optical separation unit, 306: signal light, 307 308: beam expander 309: phase mask 310/313: relay lens 311: PBS pre 312: Spatial light modulator, 314: Spatial filter, 315/1503: Objective lens, 316: Polarization direction conversion element, 317/318/322/502: Mirror, 319/324/1101/1505: Angle control unit, 320, 323, 1102, 1504: actuator, 321, 501: lens, 325: photodetector, 503a, 504a, 503b, 504b: point, 507a, 507b: area, 505a, 508a, 505b, 508b: innermost angle, 506a · 509a · 506b · 509b: outermost angle, 509: width, 701 · 801: sub-controller, 702 · 802: memory, 703 · 803: memory control circuit, 704 · 804: CRC operation circuit, 705: scramble circuit, 706: Error correction coding circuit, 707: pickup ( Intermediate light modulator) interface circuit, 708/811: control line, 709/812: data line, 805: descrambling circuit, 806: error correction circuit, 807: binarization circuit, 808: image distortion correction circuit, 809 : Image position detection circuit, 810: Pickup (photodetector) interface circuit, 1103: + type mirror, 1104, 1502: Polarization direction control unit, 1203a, 1203b, 1203c, 1203d: Line, 1204a, 1204b, 1204c, 1204d: Area, 1401: half beam splitter

Claims

A hologram recording device that records information by irradiating a recording medium with signal light and reference light,
A light source unit for emitting a light beam;
An optical separation unit that separates the light beam into the signal light and the reference light,
A spatial light modulator for modulating the signal light,
An objective lens that transmits the signal light and the reference light,
A position control unit that changes the position of the signal light irradiation area that is the irradiation area of the signal light on the objective lens, and the reference light irradiation area that is the irradiation area of the reference light on the objective lens.
An angle control unit that controls an incident angle of the reference light with respect to the recording medium,
The angle control unit changes the incident angle while the signal light transmitted through the signal light irradiation area whose position is fixed by the position control unit is incident on the recording medium, so that the angle is changed at a plurality of different angles. A hologram recording device, wherein the reference light is incident on the recording medium.
The hologram recording device according to claim 1,
The hologram recording device, wherein the position control unit changes the positions such that the positions of the signal light irradiation region and the reference light irradiation region rotate around the optical axis of the objective lens.
The hologram recording device according to claim 1,
The hologram recording apparatus, wherein the position control unit changes the position such that the signal light irradiation area and the reference light irradiation area face each other with the optical axis of the objective lens as a center.
The hologram recording device according to claim 1,
Reflecting the reference light controlled by the angle control unit on a reflecting surface, having a mirror unit disposed at a position that does not reflect the signal light on the reflecting surface,
The hologram recording device, wherein the objective lens transmits the reference light reflected by the mirror unit.
The hologram recording device according to claim 4,
The hologram recording device, wherein the mirror section has a width that reflects the reference light when the incident angle is maximum.
The hologram recording device according to claim 4,
The hologram recording apparatus, wherein the spatial light modulator includes information in the signal light irradiated to a region on the focal plane of the objective lens excluding a region serving as a shadow of the mirror unit.
The hologram recording device according to claim 1,
Two angle controllers,
Extending along the reference light scanned orthogonally, and a mirror unit that reflects the reference light,
The angle control unit controls the scanning directions of the reference light to be orthogonal to each other,
The hologram recording device, wherein the objective lens transmits the reference light reflected by the mirror unit.
The hologram recording device according to claim 1,
A mirror unit that reflects the reference light controlled by the angle control unit and transmits the signal light,
The hologram recording device, wherein the objective lens transmits the reference light reflected by the mirror unit and the signal light transmitted through the mirror unit.
The hologram recording device according to claim 1,
A hologram recording device, comprising: a polarization control unit that controls polarization of the signal light and the reference light in accordance with a change in the position between the signal light irradiation region and the reference light irradiation region.
A hologram reproducing apparatus that reproduces the information from a recording medium on which information is recorded by irradiating signal light and reference light,
A light source unit for emitting a light beam;
An optical separation unit that generates reference light from the light beam,
A light detection unit that detects a reproduction light obtained as a result of the reference light being applied to the recording medium,
An objective lens that transmits the reference light and the reproduction light,
A position control unit that changes a position of a reference light irradiation area that is an irradiation area of the reference light on the objective lens,
A hologram reproducing device, comprising:
A hologram recording method for recording information by irradiating a recording medium with signal light and reference light,
Emitting a light beam from a light source;
Separating the light beam into the signal light and the reference light,
Modulating the signal light;
Recording the hologram by interfering the signal light and the reference light using an objective lens,
Changing the position of the signal light irradiation area that is the irradiation area of the signal light on the objective lens, and the reference light irradiation area that is the irradiation area of the reference light on the objective lens,
Controlling the angle of incidence of the reference light on the recording medium,
In the step of recording the hologram, by changing the incident angle while the signal light transmitted through the signal light irradiation area having a fixed position is incident on the recording medium, the reference of a plurality of different angles is performed. A hologram recording method, wherein light is incident on the recording medium.
A hologram reproducing method for reproducing the information from a recording medium on which information is recorded by irradiating signal light and reference light,
Emitting a light beam from a light source;
Generating reference light from the light beam;
Transmitting the reference light through an objective lens;
Reproducing light obtained as a result of irradiating the recording medium with the reference light is transmitted through the objective lens;
Detecting the reproduction light to reproduce the information;
Changing the position of the reference light irradiation area, which is the irradiation area of the reference light on the objective lens,
A hologram reproducing method, comprising: