JP2006267842A - Hologram reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hologram reproducing device which couples incident laser light to a desired coupling position in a waveguide layer while holding the intensity of the incident laser light and also suppressing intensity unevenness of the incident laser light in a different coupling region on an incidence surface of a waveguide hologram memory. <P>SOLUTION: The hologram reproducing device 100 deflects 1st laser light 21 in an xy plane by an optical deflecting element 11. Then 2nd laser light 22 emitted by the optical deflecting element 11 is made incident on an optical deflecting element 12. The 2nd laser light 22 incident on the optical deflecting element 12 is deflected in the xy plane. The hologram reproducing device 100 can hold the intensity of the incident laser light without widening the width of the incident laser light and suppress the intensity unevenness of the incident laser light in the different coupling region, so the laser light can be coupled to desired coupling positions in a desired waveguide layer and a coupling plane of the waveguide layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hologram reproducing apparatus, and more particularly to a desired waveguide layer of a waveguide hologram memory and a hologram reproducing apparatus for coupling incident laser light to a desired coupling position in a coupling plane of the waveguide layer.

  In recent years, with the development of mobile devices typified by mobile phones whose functions are remarkably improved, the demand for small and large-capacity memory media has increased rapidly. Waveguide hologram memories are attracting attention as memory media that meet demand.

  A waveguide hologram memory is an optical recording medium in which a plurality of concave and convex shapes are formed in the core portion of a waveguide layer. When laser light is incident on the waveguide layer, the laser light is diffracted by a plurality of concave and convex shapes. The diffracted laser light travels in a direction perpendicular to the waveguide layer, exits the waveguide hologram memory, forms an image on an image pickup device such as a CCD (charge coupled device), and reproduces information.

  On the other hand, in the development field of a liquid crystal display device that does not require a backlight, which is a development field different from the memory field, a liquid crystal display device in which a hologram is arranged instead of a backlight has been devised. In each of these two fields, it is essential to increase the size of the hologram in order to increase the capacity of the memory and the liquid crystal display device.

  Conventionally, with an increase in the size of the waveguide hologram memory, the width of the incident laser light has been increased in accordance with the width of the waveguide layer in order to couple the incident laser light to the waveguide hologram memory. For example, Japanese Patent Laid-Open No. 2003-316244 (Patent Document 1) discloses an optical input device for an optical reproducing apparatus and an optical input method for an optical reproducing apparatus using incident laser light whose width is widened by a lens.

  FIG. 13 is a top view showing a structure of an optical input device for an optical regenerator disclosed in Japanese Patent Laid-Open No. 2003-316244 (Patent Document 1). Referring to FIG. 13, a semiconductor laser having an oscillation wavelength of 660 nm is used as the semiconductor laser 101. The semiconductor laser 101 oscillates in a single longitudinal mode. The vibration direction of the electric field of the laser beam is arranged so as to be parallel to the paper surface. The laser beam 102 emitted from the semiconductor laser 101 is spread by the lens 103 so that the spread angle becomes 32 °. The spread laser beam 104 is coupled to the optical recording medium 105.

Japanese Patent Application Laid-Open No. 2003-295153 (Patent Document 2) discloses an optical deflecting device and an optical deflecting method that can have a simple structure suitable for miniaturization and weight reduction and can achieve a high-definition and high-deflection angle. ing. FIG. 14 is a diagram showing a cross-sectional structure of a liquid crystal optical phase modulation element disclosed in Japanese Patent Laid-Open No. 2003-295153 (Patent Document 2). Referring to FIG. 14, liquid crystal layer 111 is aligned by alignment layer 112 when no voltage is applied. When a voltage is applied to the liquid crystal layer 111 by the electrode 113, a refractive index distribution is formed in the liquid crystal layer 111, and the incident linearly polarized light 114 is deflected and emitted.
JP 2003-316244 A JP 2003-295153 A

  When the width of the incident laser beam is increased by a lens as in the prior art disclosed in Japanese Patent Application Laid-Open No. 2003-316244 (Patent Document 1), the intensity of the laser beam at the coupling position increases as the hologram memory becomes larger. It becomes weaker than before widening the light. Furthermore, unevenness in intensity occurs in different coupling regions as the width of the laser beam is increased.

  An object of the present invention is to maintain the intensity of the incident laser beam and suppress the occurrence of uneven intensity of the incident laser beam in different coupling regions on the incident surface of the waveguide hologram memory. It is an object of the present invention to provide a hologram reproducing apparatus that couples incident laser light to a desired coupling position.

  In summary, the present invention relates to a hologram reproducing apparatus that makes laser light incident on a waveguide hologram memory, a light source that emits laser light, a first optical system that makes the laser light parallel light, and a first optical system. The direction of the laser light emitted from the first direction is changed by the first deflection angle with respect to the incident direction, and the direction of the laser light emitted from the first light deflection element and the first light deflection element are changed. A second optical deflection element that emits laser light by changing only the second deflection angle with respect to the incident direction, and a waveguide layer that includes the laser light emitted from the second optical deflection element in the waveguide hologram memory And a second optical system optically coupled to the first optical system.

  Preferably, the first deflection angle and the second deflection angle are opposite in sign and have the same absolute value.

  More preferably, the first light deflection element changes the first deflection angle in accordance with the applied first drive voltage. The second optical deflection element changes the second deflection angle according to the applied second driving voltage. The hologram reproducing device further includes a drive unit that controls the first drive voltage and the second drive voltage.

  More preferably, the drive unit controls the first drive voltage and the second drive voltage to couple the laser beam to a desired coupling position in the coupling plane of the waveguide layer.

  More preferably, the waveguide hologram memory includes a plurality of waveguide layers, and the drive unit controls the first drive voltage and the second drive voltage, and the desired waveguide of the plurality of waveguide layers is controlled. A laser beam is coupled to the layer.

  Preferably, the waveguide hologram memory includes a first surface on which the laser light is incident and a second surface opposite to the first surface, and the laser light is incident from the second surface side. Then, the side of the waveguide hologram memory proceeds toward the first surface, and the hologram reproducing device includes an optical path conversion unit for bending the traveling direction of the laser light that has passed through the side and coupling the laser light to the first surface. Further prepare.

  According to another aspect of the present invention, there is provided a hologram reproducing apparatus that makes a laser beam incident on a waveguide hologram memory, a light source that emits a laser beam polarized in a first direction, and a first light that converts the laser beam into parallel light. An optical system, a first optical deflection element that emits laser light by changing the direction of laser light emitted from the first optical system by a first deflection angle with respect to the incident direction, and a first optical deflection element The direction of the laser light emitted from the second direction is changed by the second deflection angle with respect to the incident direction, and the second light deflection element that emits the laser light, and the polarization direction of the laser light emitted from the second light deflection element The half-wave plate rotating from the first direction to the second direction, and changing the direction of the laser light emitted from the half-wave plate by the third deflection angle with respect to the incident direction, The third light deflecting element to be emitted and the third light deflecting element to be emitted The direction of the laser beam is changed by the fourth deflection angle with respect to the incident direction, and the fourth optical deflection element that emits the laser beam and the laser beam that is emitted from the fourth optical deflection element are converted into the waveguide hologram. And a second optical system optically coupled to a waveguide layer included in the memory.

  Preferably, the first deflection angle and the second deflection angle are opposite in sign and have the same absolute value.

  Preferably, the third deflection angle and the fourth deflection angle are opposite in sign and have the same absolute value.

  Preferably, the second light deflection element, the half-wave plate, and the third light deflection element are integrally formed.

  Preferably, the second light deflection element and the half-wave plate are integrally formed.

  Preferably, the half-wave plate and the third light deflection element are integrally formed.

  Preferably, the first to fourth optical deflection elements change the first to fourth deflection angles in accordance with the applied first to fourth drive voltages, respectively. The hologram reproducing device further includes a drive unit that outputs first to fourth drive voltages.

  More preferably, the drive unit controls at least two of the first to fourth drive voltages to couple the laser beam to a desired coupling position in the coupling plane of the waveguide layer.

More preferably, the driving unit controls the first driving voltage and the second driving voltage among the first to fourth driving voltages, and couples the laser beam to a desired coupling position.
More preferably, the drive unit controls the third drive voltage and the fourth drive voltage among the first to fourth drive voltages, and couples the laser beam to a desired coupling position.

  More preferably, the waveguide hologram memory includes a plurality of waveguide layers, and the drive unit controls at least two of the first to fourth drive voltages, and a desired one of the plurality of waveguide layers is selected. Laser light is coupled to the waveguide layer.

  More preferably, the drive unit controls the first drive voltage and the second drive voltage among the first to fourth drive voltages, and couples the laser beam to a desired waveguide layer.

  More preferably, the drive unit controls the third drive voltage and the fourth drive voltage among the first to fourth drive voltages, and couples the laser light to a desired waveguide layer.

  Preferably, the waveguide hologram memory includes a first surface on which the laser light is incident and a second surface opposite to the first surface, and the laser light is incident from the second surface side. Then, the side of the waveguide hologram memory proceeds toward the first surface, and the hologram reproducing device includes an optical path conversion unit for bending the traveling direction of the laser light that has passed through the side and coupling the laser light to the first surface. Further prepare.

  According to the hologram reproducing apparatus of the present invention, the intensity of incident laser light is maintained by deflecting laser light emitted from a light source using a plurality of light deflecting elements, and incident laser light in different coupling regions is maintained. Laser light can be coupled to a desired coupling position or a desired waveguide layer in the waveguide hologram memory while suppressing occurrence of unevenness in intensity.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

[Embodiment 1]
FIG. 1 is a schematic view of a hologram reproducing apparatus of the present invention as viewed from the side of a hologram medium. FIG. 2 is a schematic view of the hologram reproducing apparatus of FIG. 1 as viewed from above the hologram medium.

  Referring to FIGS. 1 and 2, hologram reproducing apparatus 100 reproduces information from waveguide hologram memory 1. A waveguide layer 3 is provided in the waveguide hologram memory 1. Specifically, the waveguide hologram memory 1 is a slab type single mode waveguide hologram.

  The hologram reproducing apparatus 100 includes a light source 10 that emits laser light, optical deflection elements 11 and 12, a collimating lens 10A, a driving unit 15, and a cylindrical lens 2.

  When reproducing information from the waveguide hologram memory 1, laser light is emitted from the light source 10. The laser light is converted into parallel light having a predetermined width by the collimating lens 10A. The first laser beam 21 converted into parallel light by the collimator lens 10A is deflected in the xy plane by the light deflection element 11. The second laser light 22 emitted from the light deflection element 11 is incident on the light deflection element 12. The second laser light 22 incident on the light deflection element 12 is deflected in the xy plane.

  The optical deflection elements 11 and 12 deflect the laser beam when the drive voltages V1 and V2 are applied, respectively. The deflection angle also changes according to the change of the drive voltage. The drive unit 15 controls the deflection angles of the optical deflection elements 11 and 12 by controlling the drive voltages V1 and V2.

  The third laser beam 23 emitted from the light deflection element 12 is incident on the cylindrical lens 2. The third laser beam 23 is converted by the cylindrical lens 2 into a fourth laser beam 24 that is focused in the z-axis direction without being focused in the xy in-plane direction. The fourth laser beam 24 is incident on the waveguide hologram memory 1. The fourth laser beam 24 has a polarization component in the y-axis direction.

  Hereinafter, a region where the fourth laser light 24 is coupled on the incident end face of the waveguide layer 3 is referred to as a “coupling region”, and a position where the laser light is coupled inside the waveguide layer 3 is referred to as a “coupling position”. In addition, the planar region where the coupling position exists is hereinafter referred to as a “coupling surface”.

  The incident position is determined by the relationship between the deflection angle of the light deflection element 11 and the deflection angle of the light deflection element 12. More specifically, the first deflection angle formed by the first laser beam 21 and the second laser beam 22 at the emission position of the second laser beam 22 and the second deflection position at the emission position of the third laser beam 23 are described. The second deflection angle formed by the laser beam 22 and the third laser beam 22 have opposite signs and have the same absolute value. For example, if the first deflection angle is + A degrees, the second deflection angle is -A degrees, and if the first deflection angle is -A degrees, the second deflection angle is + A degrees.

  The drive unit 15 controls the drive voltages V1 and V2 so that the first deflection angle and the second deflection angle change while satisfying the above relationship. Therefore, the hologram reproducing apparatus 100 can couple the fourth laser beam 24 in parallel to the waveguide layer 3 and can control the coupling position. As a result, the hologram reproducing apparatus 100 maintains the intensity of the incident laser beam without increasing the width of the incident laser beam, and suppresses the occurrence of unevenness in the intensity of the incident laser beam in different coupling regions. Incident laser light can be coupled to the position.

  The laser light (guided light) propagating through the waveguide layer 3 is diffracted in the z-axis direction by a plurality of projections and depressions formed in the core portion of the waveguide layer 3, and is formed as a reproduced image.

  Next, specific examples of the light deflection elements 11 and 12 shown in FIGS. 1 and 2 will be described. FIG. 3 is a diagram showing a cross-sectional structure of an optical deflection element using liquid crystal.

  Referring to FIG. 3, the light deflection element 11 includes a liquid crystal layer 30. The liquid crystal layer 30 is, for example, a nematic liquid crystal layer and is homeotropically aligned. The alignment film 35 is formed on the surface of the electrode 33 provided on the first transparent substrate 31 and on the surface of the electrode 34 provided on the second transparent substrate 32. In each of the first transparent substrate 31 and the second transparent substrate 32, an antireflection film 36 is formed on the surface opposite to the surface on which the electrodes are provided. Although not clearly shown in FIG. 3, the first transparent substrate 31 and the second transparent substrate 32 are fixed via spacers so that the liquid crystal layer 30 maintains a predetermined constant thickness. For example, glass is used as the transparent substrate.

  FIG. 4 is a diagram illustrating the operation of the liquid crystal layer 30 of FIG. FIG. 5 is a diagram showing an extraordinary refractive index distribution in the y-axis direction of the liquid crystal layer 30 of FIG.

  4 and 5, electrode 34 includes electrodes 34a and 34b. FIG. 4 shows a state in which no voltage is applied to any of the electrodes 34a and 34b. The liquid crystal layer 30 is aligned perpendicular to the first transparent substrate 31 and the second transparent substrate 32.

  The incident linearly polarized light 37 has a polarization component in the y-axis direction. At this time, the incident light 41 having a polarization component perpendicular to the alignment direction of the liquid crystal travels straight as in the case of passing through a simple glass plate. Therefore, the distribution of the extraordinary light refractive index n (y) is uniform in the y-axis direction.

  FIG. 6 is a diagram showing a state in which a voltage is applied only to the electrode 34a of FIG. FIG. 7 is a diagram illustrating the distribution of the extraordinary light refractive index in the y-axis direction of the liquid crystal layer 30 of FIG.

  Referring to FIGS. 6 and 7, the liquid crystal molecules in the portion to which a voltage is applied are aligned parallel to the substrate. In the portion where no electrode is formed, the liquid crystal molecules gradually change direction from vertical to parallel. In the liquid crystal layer 30, an operating point is determined in advance so that the distribution of the extraordinary refractive index n (y) as a function of the position y changes linearly.

  The thickness d of the liquid crystal layer 30 is constant. In the interval L between the electrode 34a and the electrode 34b where the extraordinary refractive index n (y) varies linearly, the incident linearly polarized light 37 propagating through the liquid crystal layer 30 has a large extraordinary refractive index n (y). Propagates slowly and propagates quickly where the extraordinary refractive index n (y) is small. For this reason, the course of light is bent. If the deflection angle when the light path is bent is θ, the deflection angle θ is expressed by the following equation (1).

θ = d × Δn / L [rad] (1)
Here, Δn represents the difference in the extraordinary light refractive index n (y) at the end points a and b which are the end points of the distance L between the electrodes. As described above, if the distribution of the extraordinary refractive index n (y) in the liquid crystal layer 30 of the light deflecting element is linear, the wavefront of the outgoing linearly polarized light 38 is also flat as in the case of the incident linearly polarized light 37. Therefore, the outgoing linearly polarized light 38 can be deflected by the angle θ with respect to the incident linearly polarized light 37.

  FIG. 8 is a schematic diagram showing another configuration of the hologram reproducing apparatus according to the first embodiment when viewed from the side of the hologram medium. FIG. 9 is a schematic view of the hologram reproducing apparatus of FIG. 8 as viewed from above the hologram medium.

  Referring to FIGS. 8 and 9, hologram reproducing apparatus 100 </ b> A is illustrated in that a part of the optical path from optical deflecting element 11 to optical deflecting element 12 is arranged above the medium surface of waveguide hologram memory 1. 1 and the hologram reproducing apparatus 100 shown in FIG. Specifically, the hologram reproducing device 100A is different from the hologram reproducing device 100 in that the light source 10, the light deflecting elements 11 and 12, and the collimating lens 10A are arranged above the medium surface of the waveguide hologram memory 1. The hologram reproducing device 100A is different from the hologram reproducing device 100 in that it further includes two mirror portions 25. Since other parts of hologram reproducing apparatus 100A are the same as those of hologram reproducing apparatus 100, the following description will not be repeated.

  When information is reproduced from the waveguide hologram memory 1, the laser light emitted from the light source 10 is converted into parallel light by the collimator lens 10A. The laser light is emitted from the surface opposite to the incident surface that couples the incident laser light to the waveguide hologram memory 1 toward the incident surface. The first laser light 21 emitted from the collimator lens 10A is deflected in the xy plane by the light deflection element 11. The second laser light 22 emitted from the light deflection element 11 is incident on the light deflection element 12. The second laser light 22 incident on the light deflection element 12 is deflected in the xy plane and emitted from the light deflection element 12.

  The tip of the third laser beam 23 emitted from the optical deflection element 12 is tilted by 45 ° with respect to the traveling direction of the laser beam in order to emit the third laser beam 23 by bending it by 90 °. Two mirror portions 25 are provided. The two mirror parts 25 correspond to the optical path changing part in the hologram reproducing apparatus of the present invention.

  The third laser beam 23 that has passed through the two mirror portions 25 is incident on the cylindrical lens 2. The third laser beam 23 is converted by the cylindrical lens 2 into a fourth laser beam 24 that is focused in the z-axis direction without being focused in the xy in-plane direction. The fourth laser beam 24 is incident on the waveguide layer 3.

  As an example using the light deflection elements 11 and 12, when the thickness d of the liquid crystal layer 30 in FIG. 3 is 200 μm, the distance L between the electrodes is 100 μm, and the refractive index difference Δn of the liquid crystal layer 30 is 0.25, From equation (1), the deflection angle θ is about 28.7 °.

  The value of the deflection angle θ is such that when the hologram reproducing device 100A reproduces a square waveguide hologram memory, the laser beam is coupled to all coupling positions of the waveguide layer 3 without increasing the area on the xy plane. Indicates that control can be performed. Further, in the case of a rectangular waveguide hologram memory, the hologram reproducing apparatus 100A is arranged under the condition of the deflection angle θ by arranging the light source so as to emit laser light from the light source 10 along the long axis direction. It is possible to control the laser beam to be coupled to all coupling positions. If the deflection angle does not reach the desired angle, an optical deflection element identical to the optical deflection elements 11 and 12, or an element such as a prism may be added.

  8 and 9, the optical deflection elements 11 and 12 are arranged along the upper surface of the waveguide hologram memory 1, but a part of the optical path of the laser beam from the optical deflection element 11 to the optical deflection element 12 is as follows. The waveguide hologram memory 1 may be disposed along the side surface or the lower surface. That is, it suffices if a part of the optical path of the laser beam is provided so that the laser beam travels beside the waveguide hologram memory 1.

  As described above, according to the first embodiment, by using two optical deflection elements, the intensity of the incident laser light is maintained without increasing the width of the incident laser light, and the incident laser light is different in different coupling regions. Incident laser light can be coupled to a desired coupling position while suppressing occurrence of unevenness in intensity.

[Embodiment 2]
In the hologram reproducing apparatus according to the first embodiment, the coupling position is controlled in one waveguide layer. The hologram reproducing apparatus according to the second embodiment can couple incident laser light to a desired waveguide layer when selecting a coupling position of laser light in a hologram medium including a plurality of waveguide layers.

  FIG. 10 is a diagram showing a schematic configuration of a hologram reproducing device for coupling incident laser light to a desired waveguide layer among a plurality of waveguide layers.

  Referring to FIG. 10, hologram reproducing apparatus 100 </ b> B is different from hologram reproducing apparatus 100 </ b> A in FIG. 8 in that half-wave plate 42 is further provided on the exit surface side of light deflection element 12. The hologram reproducing device 100B is different from the hologram reproducing device 100A in that the light deflecting elements 11 and 12 deflect the laser light in the yz plane. Since the configuration of other parts of hologram reproducing apparatus 100B is the same as that of hologram reproducing apparatus 100A, the following description will not be repeated.

  Laser light emitted from the light source 10 is collimated by the collimating lens 10A. The first laser light 21 converted into parallel light by the collimator lens 10A is deflected in the yz plane by the light deflection element 11. The second laser light 22 emitted from the light deflection element 11 is incident on the light deflection element 12. The second laser light 22 incident on the light deflection element 12 is deflected in the yz plane, passes through the half-wave plate 42 and is emitted as the third laser light 23.

  Here, the first laser beam 21 and the second laser beam 22 have a polarization component in the z-axis direction. The third laser beam 23 becomes light having a polarization component in the y-axis direction by the half-wave plate 42.

  The third laser beam 23 emitted from the half-wave plate 42 is tilted 45 ° with respect to the traveling direction of the laser beam in order to bend the third laser beam 23 by 90 ° and emit it. Two mirror parts 25 are provided. The third laser beam 23 that has passed through the two mirror portions 25 enters the lens 26. The third laser beam 23 is converted by the lens 26 into the fourth laser beam 24 which is not condensed in the xy plane direction but is condensed only in the z-axis direction. The fourth laser beam 24 is coupled to a desired waveguide layer 3 of the waveguide hologram memory 1.

  The waveguide layer 3 to which the fourth laser beam 24 is coupled is selected according to the relationship between the deflection angle of the optical deflection element 11 and the deflection angle of the optical deflection element 12. More specifically, the first deflection angle between the first laser beam 21 and the second laser beam 22 at the emission position of the second laser beam 22 and the first deflection angle at the emission position of the third laser beam 23 are described. The second deflection angle formed by the second laser beam 22 and the third laser beam 23 has opposite signs and satisfies the relationship in which the absolute values are equal. For example, if the first deflection angle is + A degrees, the second deflection angle is -A degrees.

  The lens 26 has a structure having a plurality of cylindrical lenses. The pitch of the cylindrical lens in the z-axis direction, the pitch between the waveguide layers 3, and the width of the third laser light 23 are equal. When the pitch of the cylindrical lens in the z-axis direction is equal to the pitch between the layers of the waveguide layer 3 and the width of the third laser beam 23 is larger than these two pitches, On the way, the hologram reproducing apparatus 100B controls the laser light contributing to the coupling by newly providing a mechanism for selecting the laser light that can be transmitted or by newly providing a mechanism for deflecting the laser light in the optical path after the lens 26. be able to.

  In order to couple the incident laser beam to the desired waveguide layer 3, the hologram reproducing device 100B does not include the two mirror portions 25, and may have the same configuration as the hologram reproducing device 100 of FIGS. .

  FIG. 11 is a schematic view of the hologram reproducing device of the second embodiment as viewed from the side of the hologram medium. FIG. 12 is a schematic view of the hologram reproducing apparatus of FIG. 11 as viewed from above the hologram medium.

  Referring to FIGS. 11 and 12, hologram reproducing apparatus 100C is different from hologram reproducing apparatus 100B in FIG. 10 in that optical deflection elements 13 and 14 are further provided. Since the configuration of other parts of hologram reproducing apparatus 100C is the same as that of hologram reproducing apparatus 100B, the following description will not be repeated. Since the configuration of each of the optical deflection elements 13 and 14 is the same as that of the optical deflection element 11 shown in FIG. 3, the configuration of each of the optical deflection elements 13 and 14 will not be described hereinafter.

  The light deflection element 12, the half-wave plate 42, and the light deflection element 13 are integrally formed. By configuring the optical deflection elements 12 and 13 and the half-wave plate 42 in this manner, the hologram reproducing device 100C can be reduced in size. The half-wave plate 42 is sandwiched between transparent substrates of the light deflection elements 12 and 13 made of glass. Therefore, even if the half-wave plate 42 is made of resin or the like, it is difficult to be deformed, so that the reliability of the hologram reproducing device is increased.

  As for the light deflection element 12, the half-wave plate 42, and the light deflection element 13, two of the light deflection element 12 and the half-wave plate 42 may be integrated, or a half wavelength. Two of the plate 42 and the light deflection element 13 may be integrated. Even with such a configuration, the hologram reproducing device 100C can be downsized.

  The operation of the hologram reproducing device 100C will be described. The first laser light 21 emitted from the light source 10 and converted into parallel light by the collimator lens 10A is deflected in the yz plane by the light deflecting element 11. The second laser light 22 emitted from the light deflection element 11 is incident on the light deflection element 12. The second laser light 22 incident on the light deflection element 12 is deflected in the yz plane and emitted from the light deflection element 12. Each of the first laser beam 21 and the second laser beam 22 has a polarization component in the z-axis direction.

  The second laser light 22 emitted from the light deflection element 12 has its polarization direction changed by the half-wave plate 42 and has a polarization component in the y-axis direction. The laser light emitted from the half-wave plate 42 is deflected in the xy plane by the light deflecting element 13. The third laser beam 23 emitted from the optical deflection element 13 is incident on the optical deflection element 14. The third laser beam 23 incident on the optical deflection element 14 is deflected in the xy plane and emitted from the optical deflection element 14. The fourth laser light 24 emitted from the light deflection element 14 has a polarization component in the y-axis direction.

  The light deflection elements 13 and 14 can change the deflection angle in accordance with each change in the drive voltages V3 and V4 output from the drive unit 15.

  In front of the emitted fourth laser beam 24, two mirror portions 25 are provided which are inclined at 45 ° with respect to the traveling direction of the laser beam in order to bend and emit the fourth laser beam 24 by 90 °. It is done. The fourth laser light 24 that has passed through the two mirror portions 25 enters the lens 26. The fourth laser beam 24 is converted by the lens 26 into a fifth laser beam 27 that is focused only in the z-axis direction without being focused in the xy in-plane direction. The fifth laser beam 27 is incident on the waveguide hologram memory 1.

  Of the plurality of waveguide layers 3, the waveguide layer 3 on which the fifth laser beam 27 is incident is determined by the relationship between the first deflection angle by the optical deflection element 11 and the second deflection angle by the optical deflection element 12. The coupling position of the fifth laser beam 27 is determined by the relationship between the third deflection angle by the optical deflection element 13 and the fourth deflection angle by the optical deflection element 14.

  Specifically, the first deflection angle in the z-axis direction formed by the first laser beam 21 and the second laser beam 22 at the emission position of the second laser beam 22 and the emission of the third laser beam 23. The second deflection angle in the z-axis direction formed by the second laser beam 22 and the third laser beam 22 at the position is opposite in sign and has the same absolute value. Further, the third deflection angle in the y-axis direction formed by the second laser beam 22 and the third laser beam 23 at the emission position of the third laser beam 23 and the third deflection angle at the emission position of the fourth laser beam 23. The fourth deflection angle in the y-axis direction formed by the third laser beam 23 and the third laser beam 22 is opposite in sign and has the same absolute value.

  Therefore, the hologram reproducing apparatus 100C maintains the intensity of the incident laser light without increasing the width of the incident laser light, and suppresses the occurrence of uneven intensity of the incident laser light in different coupling regions, and the desired coupling position and Incident laser light can be coupled to the desired waveguide layer.

  Note that the hologram reproducing device 100C may be configured such that the light deflection elements 11 and 12 deflect the laser light in the xy plane and the light deflection elements 13 and 14 deflect the laser light in the yz plane.

  In FIGS. 11 and 12, the optical deflection elements 11 to 14 are arranged along the upper surface of the waveguide hologram memory 1. In this case, a part of the optical path of the laser light is disposed on the upper surface of the waveguide hologram memory 1, but a part of the optical path of the laser light may be disposed along the side surface and the lower surface of the waveguide hologram memory 1. Good. That is, it suffices if a part of the optical path of the laser light is provided so that the laser light travels beside the waveguide hologram memory 1.

  As described above, according to the second embodiment, the coupling region is provided by including the two optical deflection elements that deflect the laser light in the yz plane and the two optical deflection elements that deflect the laser light in the xy plane. The incident laser light can be coupled to the desired coupling position and the desired waveguide layer while suppressing the occurrence of uneven intensity of the incident laser light.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is the schematic which looked at the hologram reproducing apparatus of this invention from the side of the hologram medium. It is the schematic which looked at the hologram reproduction apparatus of FIG. 1 from the upper direction of the hologram medium. It is a figure which shows the cross-section of the optical deflection | deviation element using a liquid crystal. FIG. 4 is a diagram illustrating an operation of a liquid crystal layer 30 in FIG. 3. It is a figure which shows the extraordinary-light refractive index distribution of the y-axis direction of the liquid crystal layer 30 of FIG. It is a figure which shows the state which applied the voltage only to the electrode 34a of FIG. It is a figure which shows the extraordinary-light refractive index distribution of the y-axis direction of the liquid crystal layer 30 of FIG. FIG. 8 is a schematic diagram showing another configuration of the hologram reproducing apparatus according to the first embodiment when viewed from the side of the hologram medium. It is the schematic which looked at the hologram reproduction apparatus of FIG. 8 from the upper direction of the hologram medium. It is a figure which shows schematic structure of the hologram reproducing apparatus which couple | bonds an incident laser beam to the desired waveguide layer among several waveguide layers. It is the schematic which looked at the hologram reproduction apparatus of Embodiment 2 from the side of the hologram medium. It is the schematic which looked at the hologram reproducing apparatus of FIG. 11 from the upper direction of the hologram medium. It is a top view which shows the structure of the optical input device for optical reproduction apparatuses disclosed by Unexamined-Japanese-Patent No. 2003-316244 (patent document 1). It is a figure which shows the cross-section of the liquid crystal optical phase modulation element disclosed by Unexamined-Japanese-Patent No. 2003-295153 (patent document 2).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Waveguide hologram memory, 2 Cylindrical lens, 3 Waveguide layer, 10 Light source, 10A Collimate lens, 11-14 Optical deflection element, 15 Drive part, 21 1st laser beam, 22 2nd laser beam, 23 3rd Laser beam, 24 fourth laser beam, 25 mirror part, 26 lens, 27 fifth laser beam, 30 liquid crystal layer, 31 first transparent substrate, 32 second transparent substrate, 33, 34, 34a, 34b electrode, 35 alignment film, 36 antireflection film, 37 incident linearly polarized light, 38 outgoing linearly polarized light, 41 incident light, 42 1/2 wavelength plate, 100, 100A to 100C hologram reproducing device, 101 semiconductor laser, 102, 104 laser light, 103 Lens, 105 optical recording medium, 111 liquid crystal layer, 112 alignment layer, 113 electrode, 114 incident linearly polarized light, a and b ends , L interval.

Claims (20)

A hologram reproducing device for entering laser light into a waveguide hologram memory,
A light source that emits the laser light;
A first optical system that converts the laser light into parallel light;
A first optical deflection element that changes the direction of the laser beam emitted from the first optical system by a first deflection angle with respect to the incident direction, and emits the laser beam;
A second light deflecting element that changes the direction of the laser light emitted from the first light deflecting element by a second deflection angle with respect to the incident direction and emits the laser light;
A hologram reproducing apparatus comprising: a second optical system that optically couples the laser light emitted from the second optical deflection element to a waveguide layer included in the waveguide hologram memory.   The hologram reproducing device according to claim 1, wherein the first deflection angle and the second deflection angle have opposite signs and equal absolute values. The first light deflection element changes the first deflection angle according to a first driving voltage applied,
The second optical deflection element changes the second deflection angle in accordance with an applied second driving voltage,
The hologram reproduction apparatus according to claim 2, further comprising a drive unit that controls the first drive voltage and the second drive voltage.   The said drive part controls the said 1st drive voltage and the said 2nd drive voltage, The said laser beam is couple | bonded with the desired coupling position in the coupling surface of the said waveguide layer. Hologram playback device. The waveguide hologram memory includes a plurality of waveguide layers,
The said drive part controls the said 1st drive voltage and the said 2nd drive voltage, The said laser beam is couple | bonded with the desired waveguide layer of these waveguide layers. Hologram reproducing device. The waveguide hologram memory includes a first surface on which the laser light is incident, and a second surface on the opposite side of the first surface,
The laser light is incident from the second surface side, proceeds sideways of the waveguide hologram memory toward the first surface,
The hologram reproducing apparatus according to claim 1, further comprising an optical path changing unit configured to bend a traveling direction of the laser light that has passed through the side and to couple the laser light to the first surface. A hologram reproducing device for entering laser light into a waveguide hologram memory,
A light source that emits laser light polarized in a first direction;
A first optical system that converts the laser light into parallel light;
A first optical deflection element that changes the direction of the laser light emitted from the first optical system by a first deflection angle with respect to the incident direction, and emits the laser light;
A second light deflecting element that changes the direction of the laser light emitted from the first light deflecting element by a second deflection angle with respect to the incident direction, and emits the laser light;
A half-wave plate for rotating the polarization direction of the laser light emitted from the second light deflection element from the first direction to the second direction;
Changing the direction of the laser beam emitted from the half-wave plate by a third deflection angle with respect to the incident direction, and emitting a laser beam;
A fourth light deflecting element that emits the laser light by changing the direction of the laser light emitted from the third light deflecting element by a fourth deflection angle with respect to the incident direction;
A hologram reproducing apparatus comprising: a second optical system that optically couples the laser light emitted from the fourth optical deflection element to a waveguide layer included in the waveguide hologram memory.   The hologram reproducing apparatus according to claim 7, wherein the first deflection angle and the second deflection angle have opposite signs and equal absolute values.   The hologram reproducing apparatus according to claim 7, wherein the third deflection angle and the fourth deflection angle are opposite in sign and equal in absolute value.   The hologram reproducing apparatus according to claim 7, wherein the second optical deflection element, the half-wave plate, and the third optical deflection element are integrally formed.   The hologram reproducing apparatus according to claim 7, wherein the second light deflection element and the half-wave plate are integrally formed.   The hologram reproducing apparatus according to claim 7, wherein the half-wave plate and the third light deflection element are integrally formed. The first to fourth optical deflection elements change the first to fourth deflection angles, respectively, according to the applied first to fourth drive voltages,
The hologram reproducing apparatus according to claim 7, further comprising a driving unit that outputs the first to fourth driving voltages.   The drive unit controls at least two of the first to fourth drive voltages to couple the laser light to a desired coupling position in a coupling plane of the waveguide layer. Hologram reproducing device.   The drive unit controls the first drive voltage and the second drive voltage among the first to fourth drive voltages, and couples the laser beam to the desired coupling position. 14. The hologram reproducing device according to 14.   The drive unit controls the third drive voltage and the fourth drive voltage among the first to fourth drive voltages, and couples the laser beam to the desired coupling position. 14. The hologram reproducing device according to 14. The waveguide hologram memory includes a plurality of waveguide layers,
The drive unit controls at least two of the first to fourth drive voltages, and couples the laser light to a desired waveguide layer of the plurality of waveguide layers. The hologram reproducing apparatus as described.   The drive unit controls the first drive voltage and the second drive voltage among the first to fourth drive voltages, and couples the laser light to the desired waveguide layer. Item 20. A hologram reproducing device according to Item 17.   The drive unit controls the third drive voltage and the fourth drive voltage among the first to fourth drive voltages, and couples the laser light to the desired waveguide layer. Item 20. A hologram reproducing device according to Item 17. The waveguide hologram memory includes a first surface on which the laser light is incident, and a second surface on the opposite side of the first surface,
The laser light is incident from the second surface side, proceeds sideways of the waveguide hologram memory toward the first surface,
The hologram reproducing apparatus according to claim 7, further comprising an optical path changing unit configured to bend a traveling direction of the laser light that has passed through the side and to couple the laser light to the first surface.

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