JP4419616B2 - Holographic recording system - Google Patents

Description

  The present invention relates to a holographic recording system.

  One storage technology that can store large amounts of digital information is holographic memory.

  This holographic memory is excellent in that it has a high speed and a large capacity, but there is a problem that the holographic memory system is large and expensive.

  This is because the laser light used at the time of recording requires coherence and wavelength stability, so that the laser light source becomes large and expensive (for example, Patent Document 1).

Japanese Patent Laid-Open No. 2002-207412

  In the holographic memory system as described above, since the laser light sources are large and expensive, it is difficult to provide a plurality of them. Therefore, the recording medium is sequentially irradiated with the laser light from a single light source. Thus, there is a problem in that information is reproduced and the reproduction data rate is limited.

  The present invention has been made in view of the above problems, and can greatly improve the reproduction data rate, and can reproduce information at a plurality of locations at the same time by using a plurality of inexpensive laser diodes. An object of the present invention is to provide a holographic recording system for forming a hologram on a recording medium.

  As a result of earnest research, the present inventor has formed a hologram in a hologram cell arranged in a two-dimensional array, and this hologram cell is used for reproduction from a servo mirror in which a plurality of micromirrors are arranged in an array. It was found that information can be reproduced simultaneously from a plurality of image sensors by irradiating light simultaneously.

  That is, the following object can be achieved by the present invention described below.

(1) A laser light source, a signal optical system branched from the laser light from the laser light source, modulated in accordance with digital information to be recorded and guided to a recording medium, and branched from the laser light A reference optical system for guiding reference light to the recording medium, and a hologram for forming a hologram on the recording medium by optical interference when the signal light and reference light are simultaneously irradiated onto the recording medium. In the graphic recording system, the recording medium includes a plurality of hologram cells arranged in a two-dimensional array with the X-axis direction as a row and the Y-axis direction as a column, and each hologram cell receives signal light from the Y-axis direction. And a hologram can be formed when reference light is simultaneously irradiated from the Z-axis direction. In the reference optical system, a servo mirror array and a lens array are arranged in this order from the laser light source side. The servo mirror array is provided so as to be spaced apart from the recording medium in parallel in the Z-axis direction, and corresponds to a linear array in the Y-axis direction corresponding to one row of hologram cells in the recording medium. disposed Jo, and the Y-axis direction of the reference light, the corresponding oN position to reflect the hologram cell direction, a selectively controllable to the OFF position that does not reflect in the same direction, before Kiho program cell consists as many micromirrors column, the lens array, the number of columns of the between the servo mirror array and the recording medium, disposed in a linear array in the Y-axis direction, before Kiho program cell The holographic recording system is characterized in that each lens guides the reference light reflected from the corresponding micromirror to the corresponding hologram cell. Temu.

  (2) In the recording medium, the reference light can be selectively incident on any row corresponding to each row of the hologram cell with respect to the laser light source, the signal optical system, and the reference optical system. A translational actuator is provided that is movable in the X-axis direction and that drives at least one of the recording medium, the laser light source, the signal optical system, and the reference optical system in the X-axis direction. The holographic recording system according to (1).

(3) A laser light source, a signal optical system branched from the laser light from the laser light source, modulated in accordance with digital information to be recorded and guided to a recording medium, and branched from the laser light A reference optical system for guiding reference light to the recording medium, and a hologram for forming a hologram on the recording medium by optical interference when the signal light and reference light are simultaneously irradiated onto the recording medium. In the graphic recording system, the recording medium includes a plurality of hologram cells arranged in a two-dimensional array with the Z-axis direction as a row and the Y-axis direction as a column, and each hologram cell receives signal light from the Y-axis direction. And a hologram can be formed when reference light is simultaneously irradiated from the Z-axis direction, and the signal optical system receives signal light from the laser light source in the hologram cell in the recording medium. Branches to as many branch signal light of a row, and, which, the result with the branch optical system is provided to guide to enter the Y-axis direction in each row of hologram cells, the said reference optical system, wherein A servo mirror array and a lens array are provided in this order from the laser light source side, and the servo mirror array is provided so as to be separated from the recording medium in parallel in the Z-axis direction. Corresponding to the hologram cell, the Y-axis direction is arranged in a linear array, and the reference light in the Y-axis direction is selected as an ON position that reflects in the corresponding hologram cell direction and an OFF position that does not reflect in the same direction. a controllable, prior consists as many micromirrors columns of Kiho program cell, the lens array, between said servo mirror array said recording medium, Y-axis direction Arranged in a linear array, it consists as many lenses string before Kiho program cell, each lens, the reference light reflected from the corresponding micro-mirror, which is to guide the corresponding hologram cells A holographic recording system characterized by that.

  (4) The signal optical system is provided in the same number as the number of rows of the hologram cell, and is provided in the same number as the mirror group including the mirrors for branching the signal light, and each branch signal light should be recorded. A spatial light modulator that modulates according to digital information, and each branching optical system includes one combination of the mirror and the spatial light modulator. The holographic recording system according to 3).

  (5) The reference optical system is provided so that the reference light is incident in the Y-axis direction from the hologram cell at one end of one row in the recording medium and is transmitted through the hologram cell at the other end. The holographic recording system according to any one of (1) to (4).

  (6) The lens array includes a collimating lens array including a collimating lens that guides the reference light to the hologram cell as collimated light, and the servo mirror array and the collimating lens array are arranged on the X axis with respect to the recording medium. The holographic recording system according to any one of (1) to (5), wherein an actuator for angle multiplexing that performs translational driving in at least one of a direction and a Y-axis direction is provided.

  (7) A shift actuator that translates the recording medium in at least one of the X-axis direction and the Y-axis direction with respect to the servo mirror array and the lens array is provided. The holographic recording system according to any one of (5).

  (8) The holographic recording system according to (7), wherein the lens array includes an objective lens array that guides the reference light to the hologram cell as a spherical wave.

  (9) The lens array includes a condensing lens array, the condensing lens array is arranged in a linear array corresponding to the servo mirror array, and collects the reference light reflected from the servo mirror array. It comprises a condensing lens that illuminates, and the reference optical system is provided with a pinhole array comprising pinholes arranged at the focal position of each condensing lens that constitutes the condensing lens array (6) ), (7) or (8).

  (10) A polarization controller for adjusting the beam intensity and polarization state of reference light incident on the servo mirror array according to the position of the hologram cell in the Y-axis direction is disposed in the reference optical system. The holographic recording system according to any one of (1) to (9).

  The recording medium on which the hologram is formed by the holographic recording system according to the present invention reproduces a plurality of pieces of information simultaneously by irradiating a plurality of reference beams simultaneously from a diode array in which inexpensive laser diodes are arranged in an array. Possible recording media can be formed.

  The holographic recording system includes a laser light source, a signal optical system branched from the laser light from the laser light source, modulated in accordance with digital information to be recorded and guided to a recording medium, and the laser light. A reference optical system for guiding the branched reference light to the recording medium.

  The recording medium is composed of a plurality of hologram cells arranged in a two-dimensional array with the X-axis direction as rows and the Y-axis direction as columns, and irradiates signal light from one direction to the hologram cells in one row. A hologram can be formed when one hologram cell in the row is simultaneously irradiated with reference light from the Z-axis direction.

  In the reference optical system, a servo mirror array and a lens array are provided in this order from the laser light source side, and the servo mirror array is provided to be separated from the recording medium in parallel in the Z-axis direction. Corresponding to the hologram cells in a row, they are arranged in a linear array in the Y-axis direction, and the reference light in the Y-axis direction is selected as an ON position that reflects in the corresponding hologram cell direction and an OFF position that does not reflect in the same direction The number of micromirrors is the same as the number of hologram cells in one row.

  The lens array includes a collimating lens array that is arranged in a linear array in the Y-axis direction between the servo mirror array and the recording medium and includes the same number of collimating lenses as the micromirrors. The lens guides the reference light reflected from the corresponding micromirror to the corresponding hologram cell. The recording medium is moved in the X-axis direction by an actuator with respect to the signal optical system and the reference optical system, and a hologram can be formed by changing rows.

  Hereinafter, the holographic recording system 10 according to the first embodiment of the present invention shown in FIGS. 1 to 3 will be described.

  The holographic recording system 10 includes a laser light source 12, a polarization beam splitter 14 that splits laser light emitted from the laser light source 12 into transmitted signal light and reflected light reference light, and the signal light. Is provided with a signal optical system 18 for guiding the reference light to the recording medium 16 and a reference optical system 20 for guiding the reference light to the recording medium 16.

  In the signal optical system 18, a mirror 18A, a beam expander 19, a mirror 18B, a spatial light modulator 18C, a mirror 18D, and a Fourier lens 18E are arranged in this order from the polarization beam splitter 14 side. The beam expander 19 is for enlarging the beam diameter of signal light, and includes a lens 19A, a pinhole 19B, and a lens 19C from the mirror 18A side.

  The signal light from the signal optical system 18 that has passed through the Fourier lens 18E enters the hologram cells 17 in one row of the recording medium 16 arranged in a two-dimensional array in FIG. 1 and FIG. Is irradiated simultaneously in the right direction.

  As schematically shown in FIGS. 2 and 3, the recording medium 16 has four rows A to D, and one to eight columns, where the X-axis direction is a row and the Y-axis direction is a column. A total of 32 hologram cells 17 are formed. Here, as shown in FIG. 2, for example, the hologram cell 17 in the sixth column of the B row is set to B6.

  In the reference optical system 20, a polarization control device 22, a reference light control device 24, and a collimating lens array 26 are arranged in this order from the polarizing beam splitter 14 side.

  The polarization controller 22 is configured to adjust the polarization state and light intensity of the reference light (details will be described later). The reference light control device 24 includes a servo mirror array 30, a condenser lens array 32, and a pinhole array 34 that are attached and fixed to a housing 28 (see FIG. 5) from the polarization control device 22 side.

  The servo mirror array 30 is provided to be separated from the recording medium 16 in parallel in the Z-axis direction, and is arranged in a linear array in the Y-axis direction corresponding to the hologram cells 17 in the one row. It is composed of eight micromirrors 31. These micromirrors 31 are turned on by the control device 40 so as to reflect the reference light incident in the Y-axis direction through the polarization control device 22 in the direction of the corresponding hologram cell 17 (FIGS. 1 and 5). ), And can be selectively controlled to an OFF position (see the two-dot chain line in FIGS. 1 and 5) that does not reflect in the same direction.

  The condensing lens array 32 is formed by arranging eight condensing lenses 33 in the Y-axis direction in the same manner as the micro mirror 31 in the servo mirror array 30, and each condensing lens 33 is connected to the corresponding micro mirror 31. It is arranged on the optical axis passing through the hologram cell 17.

  The pinhole array 34 includes eight pinholes 35 and is arranged in parallel with the servo mirror array 30, the condensing lens array 32, and the collimating lens array 26, and each pinhole 35 includes a condensing lens 33. At the focal position. On the bottom surface of the housing 28, the same number of emission windows 36 as the number of the pinholes 35 are provided for emitting reference light that has passed through the pinholes 35.

  The recording medium 16 includes A1 to A8 rows, B1 to B8 rows, and C1 to C8 rows among hologram cells arranged in a two-dimensional array by a translational movement actuator 38 according to a signal from the control device 40. The hologram cell 17 in any one of the rows or rows D1 to D8 can be moved to a position where the reference light is incident.

  As shown in FIGS. 6 and 7, the polarization controller 22 includes a half-wave plate 22A and a polarization filter 22B, which are rotated around the optical axis by rotation mechanisms 23A and 23B, respectively. Thus, linearly polarized light having an arbitrary beam intensity and polarization direction can be formed regardless of the polarization state of incident light.

  The rotation mechanisms 23A and 23B are controlled by the control device 40, and are modulated according to the beam diameter of the signal light in the hologram cell 17. As shown in FIG. 2, the beam diameter of the signal light incident from the signal optical system 18 varies depending on the position of the hologram cell 17 in the Y direction, that is, the column. Since the power density increases as the beam diameter decreases, the light intensity of the reference light needs to be set higher as the beam diameter of the signal light decreases. Thereby, the contrast of the optical interference fringes can be increased.

  The hologram cell 17 constituting the recording medium 16 uses, for example, a photorefractive crystal such as LiNbO3 as a recording material as it is, and in Example 1, each hologram cell 17 has a cubic shape.

  Incidentally, as in the recording medium 44 shown in FIG. 4, each hologram cell 45 has a planar recording formed along the X-axis direction and at an angle of 45 ° with respect to the Y-axis direction and the Z-axis direction. A layer 45A may be provided. In this case, the recording layer 45A may be a coating layer such as a photopolymer.

4, the adhesive layer for sign-4 4B is for bonding each hologram cell, 44C covers the entire recording medium 44, for preventing deterioration due to protection or environmental exposure of the surface AR (anti-reflective) coated respectively Show.

  Next, a process of forming a hologram in the hologram cell 17 of the recording medium 16 by the holographic recording system 10 will be described.

  The laser light emitted from the laser light source 12 is branched into signal light as transmitted light and reference light as reflected light in the beam splitter 14.

  The signal light enters the signal optical system 18 and irradiates the recording medium 16 via a mirror 18A, a beam expander 19, a mirror 18B, a spatial light modulator 18C, a mirror 18D, and a Fourier lens 18E.

  The signal light is given a signal by a data page displayed on the spatial light modulator 18C, for example, corresponding to the digital information to be recorded in the spatial light modulator 18C.

  The reflected light from the polarization beam splitter 14 enters the reference optical system 20 as reference light (for example, s-polarized light), passes through the polarization controller 22, and is included in the eight micromirrors 31 of the servo mirror array 30. , One of the micromirrors 31 that is turned on is reflected, passes through the corresponding condensing lens 33, the pinhole 35, and the collimating lens 27, and passes through one hologram cell 17 in the recording medium 16 as collimated light. In FIG. 1, irradiation is performed from above.

  On the other hand, the transmitted light in the polarizing beam splitter 14 is applied to one row of the recording medium 16 after being given a signal by the spatial light modulator 18C as signal light (for example, p-polarized light). In the example shown in FIG. 2, the recording medium 16 is moved to a position where the hologram cell 17 in the row B, that is, B1 to B8 is irradiated with the signal light by the translational movement actuator 38.

  At this time, if, for example, the micromirror 31 numbered 6 in FIG. 1 is turned on by the control device 40, the incident reference light is reflected here, and the sixth B6 in the corresponding row B is reflected. Is incident on the hologram cell 17 and interferes with the signal light, and a hologram is formed by the optical interference fringes.

  As described above, the micromirrors 31 are sequentially turned on and off, for example, after the hologram cells 17 from B1 to B8 in row B are recorded, the recording medium 16 is moved to X by the translational movement actuator 38. Driving in the direction, the rows of the hologram cells 17 to be irradiated with the signal light and the reference light are switched, the above steps are repeated, and the recording of the hologram cells 17 in all rows is completed.

  When information is reproduced from the recording medium 16 on which the hologram is recorded, a two-dimensional array is formed in the X-axis direction (row) and Y-axis direction (column) corresponding to the 32 hologram cells 17 of A1 to D8. 32 laser diode arrays are provided, and each of the rows, for example, a total of four laser diodes irradiates hologram cells 17 of A1, B1, C1, and D1 from the Z-axis direction. Diffracted light is generated in the Y-axis direction of FIG. 2, and if this is provided with an imaging lens 46A and an image sensor 46B for each row as shown by a two-dot chain line in FIG. Can be played independently at the same time.

  Since the laser diode does not require strict wavelength characteristics like a laser light source at the time of recording, there is no particular problem in reproduction.

  In the hologram recording on the recording medium 16 by the holographic recording system 10, one hologram is formed in each hologram cell 17, and many holograms are recorded in each hologram cell 17 by angle multiplexing recording. Can do.

  In the case of angle multiplex recording, as shown in FIG. 5, the casing 28 is movable in the Y-axis direction by the translation base 29 and is translated in the Y-axis direction by the angle multiplex actuator 39. .

  FIG. 8 shows the relationship between the movement of the reference light in the Y direction and the modulation of the incident angle with respect to the hologram cell 17 during angle multiplexing recording. The position of the reference light incident from the polarization controller 22 reflected by the micromirror 31 in the ON state is translated by ΔY in the Y direction. At the same time, the condenser lens 33 and the pinhole 35 are also moved by ΔY in the Y axis direction. To do. On the other hand, the collimating lens array 26 is fixed, and the incident angle of the reference light from the condenser lens 33 to the collimating lens 27 is modulated by the movement in the Y-axis direction. Therefore, it is possible to modulate the incident angle θ to the hologram cell 17 shown in FIG. 8 according to ΔY, and the number of angular multiplexing recording stages can be determined by the number of modulation stages.

  Thus, when information is reproduced from the hologram cell 17 recorded by angle multiplexing, the laser diode is irradiated with the laser diodes arranged in a two-dimensional array as described above, instead of the micromirror 31, and the laser diode array. If the condensing lens 33 and the pinhole 35 are translated in the Y-axis direction with respect to the collimating lens 27, information can be reproduced from the hologram recorded in a multiple manner corresponding to the incident angle at the time of recording. .

  Next, a holographic recording system 50 according to Embodiment 2 of the present invention shown in FIG. 9 will be described.

  This holographic recording system 50 performs shift multiplex recording on each hologram cell. Instead of the collimating lens array 26, the holographic recording system 10 of the first embodiment shown in FIGS. The objective lens array 52 is provided, and other configurations are the same as those of the holographic recording system 10.

  Therefore, in the second embodiment, the same components as those of the holographic recording system 10 of the first embodiment are denoted by the same reference numerals as those in FIG.

  In the holographic recording system 50 according to the second embodiment, the objective lens array 52 includes the same number of objective lenses 53 in parallel to the condenser lens 33 and the micromirrors 31, and the hologram on the recording medium 16. The reference light incident on the cell 17 is a spherical wave.

  In the second embodiment, instead of the angle multiplexing actuator 39, there is provided a shift multiplexing actuator 54 that translates the recording medium 16 in the Y-axis direction. The shift multiplexing actuator 54 is set on the translational movement actuator 38. Alternatively, this translational movement actuator 38 may also serve as a shift multiplexing actuator.

  When the holographic recording system 50 performs shift multiplex recording on the hologram cell 17, for example, when the sixth micromirror 31 is turned ON and the reference light irradiates the hologram cell 17 in row B, column 6, that is, B6. , While irradiating the hologram cell 17 in the row B with the signal light, the recording medium 16 is moved to the right in FIG. 9, for example, by the shift multiplexing actuator 54, and then the sixth micromirror 31 is turned OFF. The third micro mirror 31 in the servo mirror array 30 is turned on so that the reference light is incident on the hologram cell 17 of B3. At this time, shift multiplex recording is performed while moving the recording medium 16 leftward in FIG. .

  In addition, when the shift multiplexing in the X-axis direction is preferentially performed, the ON position of the micromirror 31 may be fixed and the recording medium 16 may be moved in the X-axis direction by the translational movement actuator 38.

  Next, a holographic recording system 60 according to Embodiment 3 of the present invention shown in FIG. 10 will be described.

  In this holographic recording system 60, the recording medium 16 is set in the Z-axis-Y-axis plane, the hologram cells are arranged in a two-dimensional array with the Z-axis direction as rows and the Y-axis direction as columns, and the Z-axis direction. 1 and a plurality of branched signal lights in the Y-axis direction are respectively incident on the recording medium 16 to form a hologram. The holographic recording system of the first embodiment shown in FIGS. 10, the reference optical system 20 and the signal optical system 62 are disposed in the Z-axis / Y-axis plane including the recording medium 16, and the signal optical system 62 is branched halfway to form a branching optical system 64 </ b> A, The other configurations are the same as those of the holographic recording system 10.

  Accordingly, in the third embodiment, the same components as those of the holographic recording system 10 of the first embodiment are denoted by the same reference numerals as those in FIG.

The signal optical system 62 is provided in the same number as the number of rows of the hologram cell, and is provided in the same number as the mirror group 66 including mirrors 66A, 66B, 66C, and 66D for branching the signal light, and the mirrors 66A to 66D. Spatial light modulators 68A, 68B, 68C, and 68D that modulate each branched signal light according to digital information to be recorded, and the branched signal light modulated by the spatial light modulators 68A to 68D of the recording medium 16. Each of the branch optical systems 64A includes four mirrors 67 reflecting toward each row, and four Fourier lenses 69 arranged between these mirrors 67 and each row of the recording medium 16. ˜64D are composed of one combination of each of the mirrors 66A to 66D, the spatial light modulators 68A to 68D, the mirror 67, and the Fourier lens 69.

  In the third embodiment, the recording medium 16 is arranged such that a hologram can be formed when each hologram cell irradiates signal light from the Y-axis direction and reference light from the Z-axis direction simultaneously. The branch optical systems 64 </ b> A to 64 </ b> D branch the signal light from the laser light source 12 into the same number of branch signal lights as the number of rows of the hologram cells 17 in the recording medium 16 between the beam expander 19 and the recording medium 16. In addition, this is provided so as to be incident on each row of the hologram cell 17 in the Y-axis direction.

Here, the hologram cell 17 is arranged such that a hologram is formed by the signal light from the Y-axis direction and the reference light from the Z-axis direction. For example, when the recording layer 45A as shown in FIG. 4 is provided, the recording layer 45A is disposed so as to intersect the Y axis and the Z axis at about 45 °.

  Further, the mirrors 66A to 66D constituting the mirror group 66 are configured such that the light intensity of each branched signal light is equal. Specifically, the transmittances of the mirrors 66A to 66C are sequentially decreased from the mirror 66A toward the mirror 66C. The mirrors 66A to 66D, the spatial light modulators 68A to 68D, and the Fourier lens 69 may be integrally configured in a linear array.

  Next, a process of forming a hologram in the hologram cell 17 of the recording medium 16 by the holographic recording system 60 will be described.

  The laser light emitted from the laser light source 12 is branched into signal light as transmitted light and reference light as reflected light in the beam splitter 14.

  The signal light enters the signal optical system 18 and is made into four branched signal lights by the mirrors 18A, the beam expander 19, and the mirrors 66A to 66D of the mirror group 66, respectively, and the spatial light modulators 68A to 68D, respectively. Each row of the recording medium 16 is irradiated in the Y-axis direction via the mirror 67 and the Fourier lens 69.

  The branched signal light is given a signal corresponding to the digital information to be recorded in the spatial light modulators 68A to 68D.

  Reflected light from the polarization beam splitter 14 enters the reference optical system 20 as reference light, passes through the polarization controller 22, and is turned on among the eight micromirrors 31 of the servo mirror array 30. Reflected by one micromirror 31, passes through the corresponding condenser lens 33, pinhole 35 and collimator lens 27, and as a collimated light, one hologram cell 17 in the recording medium 16 is moved upward (Z Irradiate from the axial direction.

  At this time, if, for example, the micromirror 31 numbered 6 in FIG. 10 is turned ON by the control device 40, the incident reference light is reflected here, and four (A6, A6, B6, C6, and D6) are incident on the hologram cell 17 and interfere with the signal light, and a hologram is simultaneously formed in each hologram cell by the optical interference fringes.

  As described above, the micromirrors 31 are sequentially turned on and off, and the above process is repeated to complete the recording of the hologram cells 17 in all rows.

  When information is reproduced from the recording medium 16 on which the hologram is recorded, eight pieces are arranged in a linear array in the Y-axis direction (column) at the position of the micromirror 31 corresponding to the number of columns of the hologram cell 17. 2 is provided. When one of the laser diodes irradiates, for example, the hologram cell 17 in the column 6 from the Z-axis direction, the four hologram cells in the column 6 Diffracted light is generated in the Y-axis direction, and as shown by a two-dot chain line in FIG. 10, four holograms are simultaneously reproduced independently by the imaging lens 46A and the image sensor 46B provided for each row. be able to.

  In the first, second, and third embodiments, the recording medium 16 is composed of a total of 32 hologram cells 17 in rows A to D and columns 1 to 8. Corresponding to this, the servo mirror array 30 and the collection are arranged. Although the optical lens array 32, the pinhole array 34, or the objective lens array 52 is set, the present invention is not limited to this, and the hologram cell 17 of the recording medium 16 is set in a two-dimensional array. There is no limitation on the number of rows and the number of columns.

  In the first and second embodiments, the recording medium 16 can be moved in the X-axis direction by the translation actuator 38 with respect to the laser light source 12, the polarization beam splitter 14, the signal optical system 18, and the reference optical system 20. However, the present invention is not limited to this, and the recording medium 16 may be fixed and the reference optical system 20 may be translated in the X-axis direction. The same applies to the Y-axis direction.

1 is an optical system diagram showing a holographic recording system according to Embodiment 1 of the present invention. The top view which shows typically the relationship between the recording medium, the actuator for translation, and signal light in the holographic recording system A perspective view showing a recording medium in the holographic recording system Sectional drawing which shows the modification of the recording medium typically FIG. 3 is a schematic cross-sectional view including a partial block diagram showing an enlarged reference light control device portion in the first embodiment. Sectional drawing which shows typically the polarization control apparatus 22 in the Example 1 Side view along line VII-VII in FIG. Optical system diagram schematically showing the relationship between the reference light and the hologram cell at the time of angle multiplexing recording in Example 1 Optical system diagram showing a holographic recording system according to Example 2 of the present invention Optical system diagram showing a holographic recording system according to Example 3 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 50, 60 ... Holographic recording system 12 ... Laser light source 14 ... Polarization beam splitter 16, 44 ... Recording medium 17, 45, 62 ... Hologram cell 18 ... Signal optical system 18C ... Spatial light modulator 20 ... Reference optical system 22 ... polarization controller 24 ... reference light controller 26 ... collimator lens array 28 ... housing 29 ... base for translation 30 ... servo mirror array 31 ... micro mirror 32 ... condensing lens array 33 ... condensing lens 34 ... pinhole array 35 ... pinhole 38 ... translational actuator 39 ... angle multiplexing actuator 40 ... control device 45A ... recording layer 52 ... objective lens array 53 ... objective lens 54 ... shift multiplexing actuator

Claims (10)

A laser light source, a signal optical system branched from the laser light from the laser light source, modulated in accordance with digital information to be recorded and guided to a recording medium, and a reference light branched from the laser light A holographic recording system comprising: a reference optical system that leads to the recording medium, and forming a hologram on the recording medium by optical interference when the signal light and the reference light are simultaneously irradiated onto the recording medium Because
The recording medium includes a plurality of hologram cells arranged in a two-dimensional array with the X-axis direction as rows and the Y-axis direction as columns, and each hologram cell has signal light from the Y-axis direction and reference light from the Z-axis direction. A hologram can be formed when
The reference optical system is provided with a servo mirror array and a lens array in this order from the laser light source side,
The servo mirror array is provided to be separated from the recording medium in parallel in the Z-axis direction, and is arranged in a linear array in the Y-axis direction corresponding to one row of hologram cells in the recording medium, and, the Y-axis direction of the reference light, the corresponding oN position to reflect the hologram cell direction, a selectively controllable to the OFF position that does not reflect in the same direction, the same number of columns in front Kiho program cell Made of micromirrors,
The lens array is between the servo mirror array and the recording medium, disposed in a linear array in the Y-axis direction consists of the same number of lens columns in the previous Kiho program cell, each lens, A holographic recording system characterized in that reference light reflected from a corresponding micromirror is guided to a corresponding hologram cell. In claim 1,
The recording medium corresponds to each row of the hologram cell with respect to the laser light source, the signal optical system, and the reference optical system, at a position where the reference light can be selectively incident on an arbitrary row in the X-axis direction. And a translational actuator that drives at least one of the recording medium, the laser light source, the signal optical system, and the reference optical system in the X-axis direction. Graphic recording system. A laser light source, a signal optical system branched from the laser light from the laser light source, modulated in accordance with digital information to be recorded and guided to a recording medium, and a reference light branched from the laser light A holographic recording system comprising: a reference optical system that leads to the recording medium, and forming a hologram on the recording medium by optical interference when the signal light and the reference light are simultaneously irradiated onto the recording medium Because
The recording medium is composed of a plurality of hologram cells arranged in a two-dimensional array with the Z-axis direction as rows and the Y-axis direction as columns, and each hologram cell has signal light from the Y-axis direction and reference light from the Z-axis direction. A hologram can be formed when
In the signal optical system, the signal light from the laser light source is branched into the same number of branch signal lights as the number of rows of hologram cells in the recording medium, and this is divided into each row of the hologram cells in the Y-axis direction. A branching optical system that guides the light to enter is provided.
The reference optical system is provided with a servo mirror array and a lens array in this order from the laser light source side,
The servo mirror array is provided to be separated from the recording medium in parallel in the Z-axis direction, and is arranged in a linear array in the Y-axis direction corresponding to one row of hologram cells in the recording medium, and, the Y-axis direction of the reference light, the corresponding oN position to reflect the hologram cell direction, a selectively controllable to the OFF position that does not reflect in the same direction, the same number of columns in front Kiho program cell Made of micromirrors,
The lens array is between the servo mirror array and the recording medium, disposed in a linear array in the Y-axis direction consists of the same number of lens columns in the previous Kiho program cell, each lens, A holographic recording system characterized in that reference light reflected from a corresponding micromirror is guided to a corresponding hologram cell. In claim 3,
The signal optical system is provided in the same number as the number of rows of the hologram cell, and is provided in the same number as the mirror group composed of mirrors for branching the signal light, and each branch signal light is converted into digital information to be recorded. A holographic recording system, wherein each branching optical system includes a combination of each of the mirror and the spatial light modulator. . In any one of Claims 1 thru | or 4,
The signal optical system is provided so that the signal light is incident in the Y-axis direction from a hologram cell at one end of one row of the recording medium and is transmitted through the hologram cell at the other end. Graphic recording system. In any one of Claims 1 thru | or 5,
The lens array includes a collimating lens array including a collimating lens that guides the reference light to the hologram cell as collimated light,
A holographic recording system comprising an angle multiplexing actuator that translates the servo mirror array and the collimating lens array in at least one of an X-axis direction and a Y-axis direction with respect to the recording medium. In any one of Claims 1 thru | or 5,
A holographic recording system comprising a shift multiplexing actuator that translates the recording medium in at least one of an X-axis direction and a Y-axis direction with respect to the servo mirror array and the lens array. In claim 7,
The holographic recording system, wherein the lens array includes an objective lens array that guides the reference light to the hologram cell as a spherical wave. In claim 6, 7 or 8,
The lens array includes a condensing lens array. The condensing lens array is arranged in a linear array corresponding to the servo mirror array, and collects the reference light reflected from the servo mirror array. Consisting of a light lens,
A holographic recording system, wherein the reference optical system is provided with a pinhole array including pinholes arranged at a focal position of each condenser lens constituting the condenser lens array. In any one of Claims 1 thru | or 9,
A holographic device, wherein a polarization control device for adjusting a beam intensity and a polarization state of reference light incident on the servo mirror array in accordance with a position of the hologram cell in a Y-axis direction is disposed in the reference optical system. Recording system.

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