JP4106920B2 - Information playback device - Google Patents

Description

【００８２】
光照射前は、光導波層（光記録層）にはトランス体のアゾベンゼンが多く存在する。これらの分子はランダムに配向しており、マクロに見て等方的である。ある直線偏光を照射すると、それと同じ方位に吸収軸を持つアゾ分子は選択的にトランス体からシス体へ異性化される。シス体は、熱的に不安定なため再びトランス体へ異性化するが、偏光方位と直交した吸収軸を持つトランス体に緩和した分子は、もはや光を吸収せずその状態に固定される。このトランス−シス−トランス異性化サイクルの結果として、マクロに見て吸収係数及び屈折率の異方性、つまり二色性と複屈折が誘起される。このような光異性化基を含む高分子は、光異性化により高分子自身の配向も変化し大きな複屈折を誘起することができる。このように誘起された複屈折は高分子のガラス転移温度以下で安定であり、ホログラムの記録に好適である。
【００８３】
特開平１０−３４０４７９号公報に記載された下記一般式で表す側鎖にシアノアゾベンゼンを有するポリエステルは、上述した機構によってホログラム記録可能である。
【００８４】
【化２】

【００８５】
このポリエステルは室温でホログラム記録可能であり、記録されたホログラムは半永久的に保持される。更にこのポリエステルは強度変調ホログラムと偏光変調ホログラムが同時に記録可能で、かつ、それらの回折効率が等しいことから、偏光状態のホログラム記録も可能である。従って、上記一般式で表されるポリエステルは光導波層に好適である。
【００８６】
また、上記のホログラム再生装置は、特開平９−１０１７３５号公報や特開平１１−３４５４１９号公報に記載されたホログラム記録媒体の再生にも使用することができる。特開平９−１０１７３５号公報記載の記録媒体は、基板及び導波層を有する光導波路が多重に積層され、光導波路の一部または全部が光学記録材料（具体的にはバクテリオロドプシンなどのフォトクロミック材料）から構成されている。光学記録材料により記録された情報は、光導波路を導波する光のエバネッセント光を用いて読み出すことができる。また、特開平１１−３４５４１９号公報記載の記録媒体には、各導波路内のコア層及びクラッド層の少なくとも一方に導波モードの周期と略等しい周期を有する周期的散乱要因によって情報が記録されている。
【００８７】
上記の第１〜第５の実施の形態では、すべてのホログラムからの再生光を同一の光検出手段により検出する構成としたが、複数のブロックに分割して、各ブロックに対応する複数の光検出手段により、複数のホログラムからの再生光を検出する構成としてもよい。
【００８８】
上記の第１〜第５の実施の形態では、面発光レーザが５行４列のマトリックス状に配列された面発光レーザアレイを照明装置に用いる例について説明したが、例えば５行１列のように、面発光レーザ（光源）が積層方向に１次元状に配列された面発光レーザアレイを照明装置として用いてもよい。この場合も、各面発光レーザのオン・オフ制御により、機械的駆動手段を用いずに、ホログラム記録媒体の積層された複数の平面型光導波路から任意の平面型光導波路を選択することができる。また、照明装置をアクチュエータ等の駆動手段を用いて平面型光導波路の面内方向に沿って移動させる、又は各光源からのレーザ光をガルバノミラー等の走査光学系を用いて平面型光導波路の面内方向に沿って走査する等、機械的駆動手段を併用することにより、同じ平面型光導波路の端面の異なる位置からレーザ光を入射させることができる。なお、照明装置を移動させる代わりに、ホログラム記録媒体を移動させてもよい。
【００８９】
【発明の効果】
本発明の情報再生装置によれば、機械的駆動手段を用いずに、ホログラムが記録された複数の平面型光導波路が積層されたホログラム記録媒体から、各平面型光導波路に記録されている情報を選択的に再生することが可能である、という効果を奏する。また、情報を再生する平面型光導波路の切り替えを機械的駆動手段を用いずに行なうことができるので、高速且つ高精度での情報の読み出しが可能である。また、光源からのレーザ光は垂直方向に集光されると共に水平方向には集光されずに平面型光導波路に入射するので、平面型光導波路内での光強度を均一にして、効率良く情報を読み出すことができる。更に、平面型光導波路の各々に対応して配列された光源より照明光を入射するので、平面型光導波路毎に位相が異なる照明光を入射させることができ、クロストーク無く情報を再生することができる。
【図面の簡単な説明】
【図１】ホログラム記録媒体の概略構成を示す斜視図である。
【図２】第１の実施の形態に係るホログラム再生装置の概略構成を示す斜視図である。
【図３】（Ａ）及び（Ｂ）は、第１の実施の形態に係るホログラム再生装置の側面図であり、（Ｃ）は上方から見た平面図である。
【図４】（Ａ）はマイクロレンズが直接形成された照明装置の部分構成を示す斜視図であり、（Ｂ）は第２の実施の形態に係るホログラム再生装置の概略構成を示す斜視図である。
【図５】第２の実施の形態に係るホログラム再生装置の側面図である。
【図６】第３の実施の形態に係るホログラム再生装置の概略構成を示す斜視図である。
【図７】第３の実施の形態に係るホログラム再生装置の側面図である。
【図８】第３の実施の形態に係るホログラム再生装置の上方から見た平面図である。
【図９】第４の実施の形態に係るホログラム再生装置の概略構成を示す斜視図である。
【図１０】第４の実施の形態に係るホログラム再生装置の側面図である。
【図１１】第４の実施の形態に係るホログラム再生装置の上方から見た平面図である。
【図１２】第５の実施の形態に係るホログラム再生装置の概略構成を示す斜視図である。
【図１３】第５の実施の形態に係るホログラム再生装置の側面図である。
【符号の説明】
６ コア層（光導波層）
８ クラッド層
１０ ホログラム記録媒体
１２、１２Ａ 照明装置
１４ コリメートレンズ
１６ 集光レンズ
１８ 光検出手段
２０ 結像光学系
２２ 光源（面発光レーザ）
２４ 駆動制御手段
２６₁₁〜２６₅₄ マイクロレンズ
２８ マイクロレンズアレイ
３０₁₁〜３０₅₄ マイクロレンズ
３２ レンチキュラーレンズ
３４₁〜３４₅ シリンドリカルレンズ
３６、３８ シリンドリカルレンズ[0001]
BACKGROUND OF THE INVENTION
  The present inventionInformation playback deviceIn particular, desired information is reproduced from a hologram recording medium in which a plurality of planar optical waveguides on which information is recorded by a hologram are stacked.The present invention relates to an information reproducing apparatus.
[0002]
[Prior art]
A two-dimensional optical memory represented by a digital versatile disk (DVD) or the like is used as a large-capacity and high-density recording medium. The higher density of these two-dimensional optical memories is achieved by shortening the recording laser wavelength and increasing the numerical aperture (NA) of the objective lens used for the pickup, thereby reducing the laser spot used for data recording / reproduction. Has been realized. Currently, research and development of a two-dimensional optical memory using a blue-violet laser as a light source is actively performed.
[0003]
However, since there is no suitable optical material in the ultraviolet region, and there is no suitable optical material used for recording media, lenses, etc., the shortening of the recording laser wavelength is limited to the use of a blue-violet laser. However, it is considered that it is difficult to further shorten the wavelength. Further, as a method of increasing NA, a numerical aperture is increased by a refractive index multiple of the prism using a solid immersion lens (SIL) that uses a circular prism having a high refractive index to reduce a focused spot. A method has been proposed. In this method, a minute condensing spot is formed using evanescent light formed on the bottom surface of the prism. Since evanescent light is non-propagating light that is localized near the bottom surface (exit end) of the prism and exists only within the region below the wavelength of the light from the exit end of the SIL, the recording medium is arranged very close to the bottom surface of the prism. Recording and playback must be done. For this reason, there are many problems to be solved such as distance control between the recording medium and the prism and establishment of portability of the recording medium. Further, the refractive index of the prism material is at most about 2, and the recording density is improved only up to about 4 times.
[0004]
For the above reasons, there is a limit in improving the recording density in the current two-dimensional optical memory. Therefore, in order to perform high density recording of 50 GB or more per optical disk, it is necessary to record information (volume recording) in three dimensions including the depth direction of the recording medium. One such volume type recording is a holographic memory. The holographic memory is a three-dimensional optical memory that can record in a large capacity, and has high speed by batch recording and reproduction of two-dimensional data in units of pages. That is, a plurality of data pages can be recorded by being multiplexed in the same volume, and the data can be read collectively for each page. For this reason, holographic memory is attracting attention as a next-generation recording medium.
[0005]
In a holographic memory, digital data (binary data of 0 or 1) is converted into an on / off (bright / dark) pattern using a spatial light modulator and incident on a recording medium as object light. Digital hologram recording is also possible. The original binary data can be reproduced from the obtained electrical signal by irradiating the recording medium with the reference light to reproduce the object light, and receiving the reproduced object light with a photodetector and performing photoelectric conversion. Recently, more engineering viewpoints such as S / N, bit error rate evaluation or two-dimensional encoding based on the specific optical system and volume multiplex recording system of this digital holographic memory, the effect of aberration of the optical system, etc. Research from is progressing.
[0006]
As a hologram recording material, attention is paid to a polymer material that is inexpensive and can be easily formed into a disk shape. So-called photopolymers have been actively studied for ROM type media, and photosensitive polymers containing photoisomerizable groups such as azo groups are promising for rewritable media. In order to realize a large capacity with the holographic memory, it is necessary to increase the thickness of the recording layer for recording the hologram and to multiplex-record a plurality of holograms in the same volume. For example, in order to store digital data of 100 GB or more on one disk, the recording layer needs to have a thickness of 1 mm or more. However, it is very difficult and costly to make the recording layer thick while maintaining the optical quality.
[0007]
As an example of realizing a large capacity while avoiding this problem, Japanese Patent Application Laid-Open No. 9-101735 discloses a recording / reproducing method using a multilayered optical waveguide hologram recording medium. In this recording medium, a plurality of optical waveguide layers and recording layers are laminated on a substrate via a cladding layer, and an optical waveguide layer sandwiched between adjacent cladding layers constitutes a core portion of the optical waveguide.
[0008]
Reference light is incident from the end face of the optical waveguide layer of this optical recording medium, and object light (signal light) is incident from the interface of the optical waveguide layer to cause interference between the evanescent light and the object light that have leached into the recording layer. Record the hologram. In this case, the thickness of the recording layer required for recording one hologram may be as thin as several μm, and the film can be formed without impairing optical quality by a spin coating method or a casting method. Multiple hologram recording is possible by laminating a plurality of such thin recording layers. Similarly, reference light (reproduction light) is incident from the end face of the optical waveguide layer, and recorded information can be reproduced without crosstalk. The reference light is deflected by the galvanometer mirror, condensed on the end face of the waveguide, and incident from the end face of the optical waveguide layer. At this time, by adjusting the angle of the galvanometer mirror, the optical waveguide layer on which the reference light is incident can be selected.
[0009]
Japanese Laid-Open Patent Publication No. 11-345419 discloses a read-only multiple hologram information recording medium in which single mode planar optical waveguides are laminated in multiple layers and an information reading method thereof. Information is recorded in at least one of the core layer and the clad layer in each waveguide of the recording medium by a periodic scattering factor (for example, unevenness) having a period substantially equal to the period of the waveguide mode, and the waveguide is guided. Wave light is diffracted out of the waveguide due to periodic scattering factors to form a hologram image. Further, by making the end surface of the recording medium a reflection surface cut at approximately 45 °, light can be incident and guided from a direction perpendicular to the waveguide surface. In this method, the position of the condenser lens is adjusted by a high-precision fine movement mechanism (actuator, etc.) so that the focal point of incident light is coupled to the core layer portion of the desired waveguide, and a layer for reading information is selected Yes.
[0010]
Japanese Laid-Open Patent Publication No. 2000-123108 describes a reading device that reads information recorded on a multiple hologram card having a structure in which a plurality of hologram elements are spread in a card shape. In this reading apparatus, the information reading speed is improved by distributing the light from the reproduction light source and causing it to enter the plurality of hologram elements simultaneously. Each hologram element has a multilayer structure similar to that of the recording medium described in Japanese Patent Laid-Open No. 11-345419. Selection of a layer from which information is read is made by moving the reproduction light source by moving means such as a piezoelectric element. This is done by adjusting the focal position of the light.
[0011]
[Problems to be solved by the invention]
However, in the conventional information reproducing method described above, since mechanical driving means such as a galvanometer mirror or an actuator is used to access desired information, information is continuously reproduced from different optical waveguide layers. There is a problem that it is necessary to move the focused spot while maintaining high positioning accuracy, and there is a limit in improving the information reading speed.
[0012]
Further, in the reading apparatus described in Japanese Patent Application Laid-Open No. 2000-123108, even if a plurality of incident lights distributed from the same light source are simultaneously coupled to each waveguide layer overlapping in the medium thickness direction, Since light interferes with each other, in order to reproduce information without crosstalk, it is necessary to spatially separate reproduced light or to selectively control incident light using an element such as a shutter.
[0013]
  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hologram recording medium in which a plurality of planar optical waveguides on which information is recorded by a hologram are laminated without using a mechanical driving means. Information recorded on each planar optical waveguide can be selectively reproduced.Information playback deviceIt is to provide.
[0015]
[Means for Solving the Problems]
  In order to achieve the above object, the information reproducing apparatus of the present invention uses the light guided through the planar optical waveguide from the hologram recording medium in which a plurality of planar optical waveguides on which information is recorded by the hologram are laminated. An information reproducing apparatus for reproducing information recorded in a planar optical waveguide, having a plurality of light sources that can be controlled on and off independently and arranged in correspondence with each of the planar optical waveguides, Illuminating means for illuminating the hologram recording medium with illumination light from the light source;In order to correspond to a plurality of light sources arranged corresponding to the plurality of planar optical waveguides, a curvature is provided in the laminating direction of the planar optical waveguides of the hologram recording medium and a curvature is orthogonal to the laminating direction. A plurality of lenses that are not arranged in the stacking direction, a condensing optical system that collects illumination light from the light source in the stacking direction and enters the corresponding planar optical waveguide;It is characterized by providing.
[0016]
In the information reproducing apparatus of the present invention, the illumination unit that illuminates the hologram recording medium with illumination light from the light source includes a plurality of light sources that can be controlled on and off independently, corresponding to each of the planar optical waveguides. It is arranged. Accordingly, each of the light sources included in the illuminating means can be turned on / off to turn on the light sources corresponding to the predetermined planar optical waveguide for reproducing information. When the illumination light from the light source is condensed by the condensing optical system and is incident on the corresponding planar optical waveguide, the illumination light is guided through the planar optical waveguide, and the information recorded in the predetermined planar optical waveguide is recorded. Is played.
[0017]
  As a result, it is possible to selectively reproduce information recorded on each planar optical waveguide from a hologram recording medium in which a plurality of planar optical waveguides on which information is recorded by a hologram are laminated without using a mechanical driving means. can do. Further, since switching of the planar optical waveguide for reproducing information can be performed without using a mechanical driving means, information can be read at high speed and with high accuracy.Also, since the laser light from the light source is focused in the stacking direction and is not focused in the in-plane direction, it is incident on the planar optical waveguide, so that the light intensity in the planar optical waveguide is uniform and efficient. Information can be read well.Furthermore, since illumination light is incident from light sources arranged corresponding to each of the planar optical waveguides, illumination light having a different phase can be incident on each planar optical waveguide, and information can be reproduced without crosstalk. Can do.
[0018]
The information reproducing apparatus may further include detection means for detecting a hologram image reproduced by guiding illumination light through the planar optical waveguide.
[0019]
In the illumination means of the information reproducing apparatus, the plurality of light sources are arranged in a one-dimensional shape or a two-dimensional shape. For example, a plurality of light sources can be arranged in a two-dimensional manner so that a plurality of light sources are arranged along a predetermined direction and provided with a plurality of light source rows arranged corresponding to each of the planar optical waveguides. In this case, it is preferable that the number of light source arrays be equal to or more than the number of stacked planar optical waveguides. By providing as many or more light source arrays as the number of planar optical waveguides, it is possible to selectively reproduce information recorded on all the planar optical waveguides of the hologram recording medium. Further, for example, a plurality of light sources may be arranged in a one-dimensional manner along a predetermined direction so as to correspond to each of the planar optical waveguides.
[0020]
The illuminating means can be composed of, for example, a laser array in which a plurality of laser light sources are monolithically formed on the same substrate. As the laser light source, a surface emitting laser that extracts emitted light in a direction substantially perpendicular to the substrate surface is suitable. In the surface emitting laser, since the laser resonator is disposed substantially perpendicular to the substrate surface, two-dimensional arrangement and high integration can be achieved with high positional accuracy.
[0021]
The condensing optical system of the above information reproducing apparatus can include a first optical element having a collimator function and a second optical element having a condensing function. At least one of the first optical element and the second optical element can be configured by a microlens array including a plurality of microlenses corresponding to each of the plurality of light sources. The microlens array can be formed on the exit aperture surface of each of the plurality of light sources. As described above, the microlens array is integrally formed with the illumination unit, whereby the size of the apparatus can be reduced. Further, when the second optical element having a condensing function is configured by a microlens array, the focal length of each microlens can be determined according to the position where the illumination light is incident on the planar optical waveguide. Thereby, illumination light can be efficiently coupled to the planar optical waveguide.
[0023]
A hologram is recorded on a hologram recording medium in which a plurality of planar optical waveguides on which information can be recorded by a hologram are laminated so that hologram images reproduced from each of the planar optical waveguides are detected at the same position. Thus, when information is reproduced by applying the information reproducing apparatus or information reproducing method of the present invention, the hologram image reproduced from each planar optical waveguide can be detected by the same detecting means.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.The first embodiment, the second embodiment, and the fifth embodiment are used as reference examples, and the third embodiment and the fourth embodiment are used as embodiments of the present invention.
[0025]
FIG. 2 shows a schematic configuration of the hologram reproducing apparatus according to the embodiment of the present invention. In this embodiment, the cladding layer 8₁And 8₂First core layer 6 sandwiched between₁, Clad layer 8₂And 8_ThreeSecond core layer 6 sandwiched between₂, Clad layer 8_ThreeAnd 8_FourThird core layer 6 sandwiched between_Three, Clad layer 8_FourAnd 8_FiveFourth core layer 6 sandwiched between_FourAnd cladding layer 8_FiveAnd 8₆Fifth core layer 6 sandwiched between_FiveThe first to fifth core layers 6 are provided.₁~ 6_FiveA case will be described in which information is reproduced from a hologram recording medium in which are sequentially stacked from the lower layer side.
[0026]
The hologram reproducing device includes an illumination device (light supply means) 12 that illuminates the hologram recording medium 10. The hologram recording medium 10 is horizontally held at a predetermined position by a holding member (not shown). Between the illumination device 12 and the medium holding position, the collimating lens 14 that collimates the illumination light and the illumination that is collimated. A condensing optical system including a condensing lens 16 that condenses light on the end face of the planar optical waveguide is disposed. On the diffracted light emission side of the hologram recording medium 10, a light detection means 18 such as a CCD area sensor that detects the reproduced hologram image, a lens that forms an image on the light receiving surface of the light detection means 18, and the like. The imaging optical system 20 is arranged.
[0027]
The illuminating device 12 includes a surface emitting laser array in which a plurality of light sources (surface emitting lasers) 22 (Vertical Cavity Surface Emitting Laser diode: VCSEL) are arranged in a matrix of n rows and m columns on the same substrate 23. . In the surface emitting laser, by arranging the laser resonator perpendicular to the substrate surface, two-dimensional arrangement of elements and high integration can be achieved. An element arranged in n rows and m columns is a surface emitting laser 22._nmIn FIG. 2, 20 surface emitting lasers 22 are shown in FIG.₁₁~ 22₅₄Are arranged in a matrix of 5 rows and 4 columns.
[0028]
Each row of light source columns corresponds to each of the planar optical waveguides. In this example, four surface emitting lasers 22 in the first row.₁₁~ 22₁₄Is the first core layer 6 of the hologram recording medium 10₁Second, the surface emitting laser 22 in the second row_{twenty one}~ 22_{twenty four}Is the second core layer 6₂The surface emitting laser 22 in the third row₃₁~ 22₃₄Is the third core layer 6_ThreeThe surface emitting laser 22 in the fourth row₄₁~ 22₄₄Is the fourth core layer 6_FourThe surface emitting laser 22 in the fifth row₅₁~ 22₅₄Is the fifth core layer 6_FiveAre arranged so as to correspond to each.
[0029]
Surface emitting laser 22₁₁~ 22₅₄Each is connected to the drive control means 24 via a wiring (not shown), and is independently controlled on and off by the drive control means 24. As such a surface emitting laser array, for example, a VCSEL array manufactured by Fuji Xerox Co., Ltd. can be used. This VCSEL array can be driven independently with a light emission period of 1.39 μsec by matrix driving of a total of 1440 elements of 12 × 120.
[0030]
Next, the operation of the hologram reproducing apparatus will be described. FIGS. 3A and 3B are side views from the illumination device 12 to the hologram recording medium 10 of the reproducing device. As shown in FIG. 3A, for example, five surface emitting lasers 22 in the fourth row are driven by the drive control means 24.₁₄~ 22₅₄When is turned on, the laser light output from each surface emitting laser is collimated by the collimating lens 14 and condensed by the condensing lens 16 on the end surface of the planar optical waveguide of the hologram recording medium 10.
[0031]
In this example, five surface emitting lasers 22₁₄~ 22₅₄Each of the five core layers 6 of the hologram recording medium 10.₁~ 6_FiveAre arranged so as to correspond to each of the surface emitting lasers 22.₁₄The laser beam output from the first core layer 6₁The surface emitting laser 22_{twenty four}The laser beam output from the second core layer 6₂The surface emitting laser 22₃₄The laser beam output from the third core layer 6_ThreeThe surface emitting laser 22₄₄The laser beam output from the fourth core layer 6_FourThe surface emitting laser 22₅₄The laser beam output from the fifth core layer 6_FiveCondensed on the end face of
[0032]
5 core layers 6₁~ 6_FiveThe laser light incident from each end face of the light is guided through the planar optical waveguide including each core layer, diffracted by the hologram recorded in each planar optical waveguide, and transmitted through the other core layer and cladding layer. Then, five hologram images are formed on the light receiving surface of the light detection means 18 by the imaging optical system 20. The reproduced hologram images are respectively detected by the light detection means 18. That is, the five core layers 6₁~ 6_FiveAre simultaneously selected, and information recorded as a hologram on the planar optical waveguide including each core layer is simultaneously reproduced.
[0033]
In the above, five surface emitting lasers 22 in the fourth column₁₄~ 22₅₄5 core layers 6 in the ON state₁~ 6_FiveAlthough the example in which the laser beam is incident on each of the end surfaces of the laser beam has been described, the core layer on which the laser beam is incident can be switched by controlling the surface emitting laser on / off by the drive control means 24. For example, as shown in FIG. 3B, two surface emitting lasers 22 among the surface emitting lasers in the fourth column are driven by the drive control means 24.₁₄And 22₃₄Is turned on, and three surface emitting lasers 22_{twenty four}, 22₄₄And 22₅₄Is turned off, the surface emitting laser 22 in the on state is turned on.₁₄The laser beam output from the first core layer 6₁The surface emitting laser 22₃₄The laser beam output from the third core layer 6_ThreeCondensed on the end face of That is, the two core layers 6₁And 6_ThreeAre simultaneously selected, and two hologram images are formed on the light receiving surface of the light detection means 18 by the imaging optical system 20.
[0034]
In addition, when a plurality of holograms are recorded on one planar optical waveguide, each hologram can be reproduced by making a laser beam incident on each recording area. FIG. 3C is a plan view of the reproducing apparatus as viewed from above. For example, as shown in FIG. 3C, four surface emitting lasers 22 in the first row are driven by the drive control means 24.₁₁~ 22₁₄Is turned on, the laser light output from each surface emitting laser is collimated by the collimating lens 14, and the first core layer 6 is collected by the condenser lens 16.₁The light is condensed at different positions on the end face. In this example, four surface emitting lasers 22₁₁~ 22₁₄Are each a core layer 6 of the hologram recording medium 10.₁Are arranged so as to correspond to each of the four recording areas, and the core layer 6₁Each of the laser beams incident from different positions on the end surface of the light is guided through the planar optical waveguide, is diffracted by the hologram recorded in each recording area, and is formed on the light receiving surface of the light detecting means 18 by the imaging optical system 20. Four hologram images are formed. That is, one core layer 6₁A plurality of recording areas are simultaneously selected, and a plurality of information recorded as holograms is simultaneously reproduced for each recording area.
[0035]
As described above, the hologram reproducing apparatus according to this embodiment turns on and off each of the light sources of the illuminating device to guide the illuminating light from a plurality of stacked planar optical waveguides of the hologram recording medium. Two or more planar optical waveguides can be selected, and any hologram (information) recorded in each planar optical waveguide can be selectively reproduced. In addition, when a plurality of holograms are recorded on one planar optical waveguide, each hologram can be reproduced by making a laser beam incident on each recording area.
[0036]
Further, the planar optical waveguide from which information is read can be switched by on / off control of the light source without using a mechanical driving means, and information can be read at high speed and with high accuracy.
[0037]
Further, since the light source column in each row of the illumination light source corresponds to each of the planar optical waveguides, illumination light having a different phase can be incident on each planar optical waveguide, and recorded in a plurality of planar optical waveguides. Even if the information is played back simultaneously, crosstalk does not occur.
[0038]
(Second Embodiment)
In the hologram reproducing device according to the second embodiment, as shown in FIG. 4A, instead of arranging a collimating lens, a surface emitting laser 22 of the illumination device 12 is used.₁₁~ 22₅₄Microlens 30 is located above each exit aperture.₁₁~ 30₅₄Is formed directly. Further, as shown in FIG. 4B, instead of arranging the condenser lens, the surface emitting laser 22 of the illumination device 12 is used.₁₁~ 22₅₄Corresponding to each, microlenses 26 arranged in a matrix of 5 rows and 4 columns₁₁~ 26₅₄The microlens array 28 provided with is arranged.
[0039]
The four surface emitting lasers 22 in the first row of the lighting device 12 are also shown.₁₁~ 22₁₄Is the fifth core layer 6 of the hologram recording medium 10_FiveSecond, the surface emitting laser 22 in the second row_{twenty one}~ 22_{twenty four}Is the fourth core layer 6_FourThe surface emitting laser 22 in the third row₃₁~ 22₃₄Is the third core layer 6_ThreeThe surface emitting laser 22 in the fourth row₄₁~ 22₄₄Is the second core layer 6₂The surface emitting laser 22 in the fifth row₅₁~ 22₅₄Is the first core layer 6₁Are arranged so as to correspond to each.
[0040]
Since other configurations are the same as those of the hologram reproducing apparatus according to the first embodiment, the same portions are denoted by the same reference numerals and description thereof is omitted.
[0041]
As a method for producing a microlens, for example, Yuzo Ishii et al., Ink-Jet Fabrication of Polymer Microlens for Optical-I / O Chip Packaging, Jpn. J. Appl. Phys. Vol. 39 (2000) pp. 1490- A method using an ink jet method as reported in 1493 is suitable. This manufacturing method is a method in which an ultraviolet curable epoxy resin is used as a lens material, and the polymer is ejected and formed on a lens forming portion using an ink jet printer. Since the discharged polymer is held on the hemispherical surface by surface tension, it is cured by being irradiated with ultraviolet rays. By adjusting the discharge amount and the viscosity of the polymer before curing, a microlens can be produced with high accuracy. At this time, it is possible to eliminate the change in the contact angle due to the substrate material by coating the surface of the substrate on which the lens is formed with a fluororesin. By using this lens manufacturing method, it is possible to easily manufacture each of the surface emitting lasers provided with the microlens array and the microlens.
[0042]
Next, the operation of the hologram reproducing apparatus will be described. FIG. 5 is a side view from the illumination device 12 to the hologram recording medium 10 of the reproducing apparatus. As shown in FIG. 5, for example, five surface emitting lasers 22 in the fourth row by the drive control means 24.₁₄~ 22₅₄When the is turned on, the laser light output from each surface emitting laser is the microlens 30 formed above each opening.₁₄~ 30₅₄And the corresponding microlens 26 of the microlens array 28.₁₄~ 26₅₄Thus, the light is condensed on the end face of the planar optical waveguide of the hologram recording medium 10. In this example, five surface emitting lasers 22₁₄~ 22₅₄Each of the five core layers 6 of the hologram recording medium 10.₁~ 6_FiveFor example, a surface emitting laser 22.₁₄The laser light output from the microlens 26₁₄The fifth core layer 6_FiveCondensed on the end face of
[0043]
5 core layers 6₁~ 6_FiveThe laser light incident from each end face of the light is guided through the planar optical waveguide including each core layer, diffracted by the hologram recorded in each planar optical waveguide, and transmitted through the other core layer and cladding layer. Then, five hologram images are formed on the light receiving surface of the light detection means 18 by the imaging optical system 20. The reproduced hologram images are respectively detected by the light detection means 18. That is, the five core layers 6₁~ 6_FiveAre simultaneously selected, and information recorded as a hologram on the planar optical waveguide including each core layer is simultaneously reproduced.
[0044]
The point that the core layer on which the laser beam is incident can be switched by controlling the surface emitting laser on / off by the drive control means 24 is the same as in the first embodiment, and thus the description thereof is omitted.
[0045]
In the hologram reproducing apparatus according to the present embodiment, the same effects as those of the first embodiment can be obtained, and a coupling lens can be obtained by directly forming a microlens above the opening of each surface emitting laser of the illumination apparatus. The system can be made compact.
[0046]
(Third embodiment)
In the multiplex hologram reproducing apparatus according to the third embodiment, as shown in FIG. 6, instead of arranging a collimating lens, a surface emitting laser 22 of the illuminating device 12 is used.₁₁~ 22₅₄Microlens 30 is located above each exit aperture.₁₁~ 30₅₄Is formed directly. Further, instead of disposing a condensing lens, a cylindrical lens 34 having a vertical curvature and a long horizontal direction.₁~ 34_FiveA plurality of lenticular lenses 32 are arranged so as to correspond to each row of the surface emitting laser array of the illumination device 12.
[0047]
The four surface emitting lasers 22 in the first row of the lighting device 12 are also shown.₁₁~ 22₁₄Is the fifth core layer 6 of the hologram recording medium 10_FiveSecond, the surface emitting laser 22 in the second row_{twenty one}~ 22_{twenty four}Is the fourth core layer 6_FourThe surface emitting laser 22 in the third row₃₁~ 22₃₄Is the third core layer 6_ThreeThe surface emitting laser 22 in the fourth row₄₁~ 22₄₄Is the second core layer 6₂The surface emitting laser 22 in the fifth row₅₁~ 22₅₄Is the first core layer 6₁Are arranged so as to correspond to each.
[0048]
Since other configurations are the same as those of the hologram reproducing apparatus according to the first embodiment, the same portions are denoted by the same reference numerals and description thereof is omitted.
[0049]
Next, the operation of the hologram reproducing apparatus will be described. FIG. 7 is a side view up to 10 of the reproducing apparatus. As shown in FIG. 7, for example, the five surface emitting lasers 22 in the fourth row by the drive control means 24.₁₄~ 22₅₄When the is turned on, the laser light output from each surface emitting laser is the microlens 30 formed above each opening.₁₄~ 30₅₄And the corresponding cylindrical lens 34 of the lenticular lens 32.₁~ 34_FiveThus, the light is condensed on the end face of the planar optical waveguide of the hologram recording medium 10. In this example, five surface emitting lasers 22₁₄~ 22₅₄Each of the five core layers 6 of the hologram recording medium 10.₁~ 6_FiveFor example, a surface emitting laser 22.₁₄The laser beam output from the cylindrical lens 34₁The fifth core layer 6_FiveCondensed on the end face of
[0050]
5 core layers 6₁~ 6_FiveThe laser light incident from each end face of the light is guided through the planar optical waveguide including each core layer, diffracted by the hologram recorded in each planar optical waveguide, and transmitted through the other core layer and cladding layer. Then, five hologram images are formed on the light receiving surface of the light detection means 18 by the imaging optical system 20. The reproduced hologram images are respectively detected by the light detection means 18. That is, the five core layers 6₁~ 6_FiveAre simultaneously selected, and information recorded as a hologram on the planar optical waveguide including each core layer is simultaneously reproduced.
[0051]
The point that the core layer on which the laser beam is incident can be switched by controlling the surface emitting laser on / off by the drive control means 24 is the same as in the first embodiment, and thus the description thereof is omitted.
[0052]
A cylindrical lens having a curvature in the vertical direction and long in the horizontal direction collects the laser light in the vertical direction as described above, but has no curvature in the horizontal direction, and therefore collects the laser light in the horizontal direction. Does not shine. FIG. 8 is a plan view of the reproducing apparatus as viewed from above. For example, as shown in FIG. 8, four surface emitting lasers 22 in the first row are driven by the drive control means 24.₁₁~ 22₁₄When the is turned on, the laser light output from each surface emitting laser is the microlens 30 formed above each opening.₁₁~ 30₁₄Are collimated by the cylindrical lens 34 without being condensed in the horizontal direction.₁, And enters the multiple hologram recording medium 10.
[0053]
In the hologram reproducing apparatus according to the present embodiment, the same effects as those of the first embodiment can be obtained, and a coupling lens can be obtained by directly forming a microlens above the opening of each surface emitting laser of the illumination apparatus. The system can be made compact. In addition, the laser light from the light source is condensed in the vertical direction from the cylindrical lens arranged in the lenticular lens and is incident in the planar optical waveguide without being condensed in the horizontal direction. Information can be read efficiently with uniform light intensity.
[0054]
(Fourth embodiment)
In the hologram reproducing apparatus according to the fourth embodiment, as shown in FIG. 9, a surface emitting laser array in which a plurality of surface emitting lasers 22 are arranged in a staggered manner is used for the illumination device 12A. The zigzag pattern is an array form in which the position in the column direction is shifted for every other row in a matrix of n rows and m columns. By arranging the light sources in a staggered manner, the number of holograms that overlap in the thickness direction of the hologram recording medium can be reduced, and the influence of other holograms that the diffracted light receives can be reduced. As in the case where they are arranged in a matrix, elements arranged in n rows and m columns are represented by surface emitting lasers 22._nmRepresented by Further, instead of arranging the collimating lens, the surface emitting laser 22 of the illumination device 12A.₁₁~ 22₅₄Microlens 30 is located above each exit aperture.₁₁~ 30₅₄Is formed directly.
[0055]
Further, instead of disposing a condensing lens, a pair of cylindrical lenses 36 and 38 having different focal lengths, and a cylindrical lens 34 having a vertical curvature and a long horizontal direction.₁~ 34_FiveAre arranged so as to correspond to each row of the surface emitting laser array of the illumination device 12. Each of the pair of cylindrical lenses 36 and 38 includes a cylindrical lens 34.₁~ 34_FiveLike the above, it has a curvature in the vertical direction and extends long in the horizontal direction.
[0056]
Furthermore, the four surface emitting lasers 22 in the first row of the illumination device 12₁₁~ 22₁₄Is the first core layer 6 of the hologram recording medium 10₁Second, the surface emitting laser 22 in the second row_{twenty one}~ 22_{twenty four}Is the second core layer 6₂The surface emitting laser 22 in the third row₃₁~ 22₃₄Is the third core layer 6_ThreeThe surface emitting laser 22 in the fourth row₄₁~ 22₄₄Is the fourth core layer 6_FourThe surface emitting laser 22 in the fifth row₅₁~ 22₅₄Is the fifth core layer 6_FiveAre arranged so as to correspond to each.
[0057]
Since other configurations are the same as those of the hologram reproducing apparatus according to the first embodiment, the same portions are denoted by the same reference numerals and description thereof is omitted.
[0058]
Next, the operation of the hologram reproducing apparatus will be described. FIG. 10 is a side view up to 10 of the reproducing apparatus. As shown in FIG. 10, for example, five surface emitting lasers 22 in the fourth row are driven by the drive control means 24.₁₄~ 22₅₄When the is turned on, the laser light output from each surface emitting laser is the microlens 30 formed above each exit aperture.₁₄~ 30₅₄The collimated laser light is reduced in the vertical direction (stacking direction of the optical waveguide layer) only by the pair of cylindrical lenses 36 and 38, and the corresponding cylindrical lens 34 of the lenticular lens 32 is reduced.₁~ 34_FiveThus, the light is condensed on the end face of the planar optical waveguide of the hologram recording medium 10. In this example, five surface emitting lasers 22₁₄~ 22₅₄Each of the five core layers 6 of the hologram recording medium 10.₁~ 6_FiveFor example, a surface emitting laser 22.₁₄The laser beam output from the cylindrical lens 34_FiveThe first core layer 6₁Condensed on the end face of
[0059]
5 core layers 6₁~ 6_FiveThe laser light incident from each end face of the light is guided through the planar optical waveguide including each core layer, diffracted by the hologram recorded in each planar optical waveguide, and transmitted through the other core layer and cladding layer. Then, five hologram images are formed on the light receiving surface of the light detection means 18 by the imaging optical system 20. The reproduced hologram images are respectively detected by the light detection means 18. That is, the five core layers 6₁~ 6_FiveAre simultaneously selected, and information recorded as a hologram on the planar optical waveguide including each core layer is simultaneously reproduced.
[0060]
The point that the core layer on which the laser beam is incident can be switched by controlling the surface emitting laser on / off by the drive control means 24 is the same as in the first embodiment, and thus the description thereof is omitted.
[0061]
A cylindrical lens having a curvature in the vertical direction and long in the horizontal direction collects the laser light in the vertical direction as described above, but has no curvature in the horizontal direction, and therefore collects the laser light in the horizontal direction. Does not shine. FIG. 11 is a plan view of the reproducing apparatus as viewed from above. For example, as shown in FIG. 11, the four surface emitting lasers 22 in the first row are driven by the drive control means 24.₁₁~ 22₁₄When the is turned on, the laser light output from each surface emitting laser is the microlens 30 formed above each exit aperture.₁₁~ 30₁₄The cylindrical lenses 36 and 38 and the cylindrical lens 34 are not collimated and are not condensed in the horizontal direction.₁And enters the hologram recording medium 10.
[0062]
In the hologram reproducing apparatus according to the present embodiment, the same effects as those of the first embodiment can be obtained, and a coupling lens can be obtained by directly forming a microlens above the opening of each surface emitting laser of the illumination apparatus. The system can be made compact. In addition, the laser light from the light source is condensed in the vertical direction from the cylindrical lens arranged in the lenticular lens and is incident in the planar optical waveguide without being condensed in the horizontal direction. Information can be read efficiently with uniform light intensity.
[0063]
Further, since the laser beam is reduced only in the vertical direction (stacking direction of the optical waveguide layer) by the pair of cylindrical lenses, the density of the focused spot on the end face of the planar optical waveguide of the hologram recording medium is reduced. The thickness of each layer constituting the hologram recording medium can be reduced. Although a surface emitting laser array can be fabricated with an element interval of about several tens of μm, a reduction optical system using a pair of cylindrical lenses is effective for condensing light on a medium having a finer layer structure. is there.
[0064]
(Fifth embodiment)
As shown in FIG. 12, the hologram reproducing apparatus according to the embodiment of the present invention laminates the core layer 6 and the clad layer 8 alternately to make the planar optical waveguide multi-layered, and the end face of the recording medium is substantially the same. The present invention is applied to an information reproducing apparatus for reproducing information recorded as a hologram in each planar optical waveguide from a hologram recording medium 10A having a reflecting surface cut at 45 °. In this medium, it is possible to make light incident and guided from a direction perpendicular to the waveguide surface by using a reflecting surface whose end face is cut at approximately 45 °. Note that the hologram recording medium 10A has five core layers 6 similarly to the recording medium used in the first embodiment.₁~ 6_FiveAnd 6 cladding layers 8₁~ 8₆It has.
[0065]
The hologram reproducing device includes an illumination device 12 that illuminates the hologram recording medium 10. The hologram recording medium 10 is held horizontally at a predetermined position by a holding member (not shown), and the illuminating device 12 reflects the illumination light on the end surface of the hologram recording medium 10 cut at approximately 45 ° to pass through the planar optical waveguide. It is arranged above the hologram recording medium 10 so as to be guided.
[0066]
The illuminating device 12 includes a surface emitting laser array in which a plurality of surface emitting lasers 22 are arranged in a matrix of n rows and m columns on the same substrate 23. In FIG. 12, twenty surface emitting lasers 22₁₁~ 22₅₄Are arranged in a matrix of 5 rows and 4 columns.
[0067]
Each row of light source columns corresponds to each of the planar optical waveguides. In this example, four surface emitting lasers 22 in the first row.₁₁~ 22₁₄Is the fifth core layer 6 of the hologram recording medium 10_FiveSecond, the surface emitting laser 22 in the second row_{twenty one}~ 22_{twenty four}Is the fourth core layer 6_FourThe surface emitting laser 22 in the third row₃₁~ 22₃₄Is the third core layer 6_ThreeThe surface emitting laser 22 in the fourth row₄₁~ 22₄₄Is the second core layer 6₂The surface emitting laser 22 in the fifth row₅₁~ 22₅₄Is the first core layer 6₁Are arranged so as to correspond to each.
[0068]
Surface emitting laser 22₁₁~ 22₅₄Each is connected to the drive control means 24 via a wiring (not shown), and is independently controlled on and off by the drive control means 24. Also, the surface emitting laser 22₁₁~ 22₅₄Above each exit aperture, there is a microlens 30.₁₁~ 30₅₄Is formed directly.
[0069]
In addition, the surface emitting laser 22 of the illumination device 12 is provided between the illumination device 12 and the medium holding position.₁₁~ 22₅₄Corresponding to each, microlenses 26 arranged in a matrix of 5 rows and 4 columns₁₁~ 26₅₄The microlens array 28 provided with is arranged. Micro lens 26₁₁~ 26₅₄Each of these functions as a condenser lens that condenses the collimated illumination light on the end face of the planar optical waveguide. Micro lens 26₁₁~ 26₅₄Each has a different focal length depending on the incident position of the illumination light. On the diffracted light emission side of the hologram recording medium 10, a light detection means 18 such as a CCD area sensor that detects the reproduced hologram image, a lens that forms an image on the light receiving surface of the light detection means 18, and the like. The imaging optical system 20 is arranged.
[0070]
Next, the operation of the hologram reproducing apparatus will be described. FIG. 13 is a side view from the illuminating device 12 of the reproducing apparatus to the end face of the hologram recording medium 10. As shown in FIG. 13, for example, five surface emitting lasers 22 in the fourth row are driven by the drive control means 24.₁₄~ 22₅₄When the is turned on, the laser light output from each surface emitting laser is the microlens 30 formed above each exit aperture.₁₄~ 30₅₄And the corresponding microlens 26 of the microlens array 28.₁₄~ 26₅₄Thus, the light is condensed on the end face of the planar optical waveguide of the hologram recording medium 10. In this example, five surface emitting lasers 22₁₄~ 22₅₄Each of the five core layers 6 of the hologram recording medium 10.₁~ 6_FiveFor example, a surface emitting laser 22.₁₄The laser light output from the microlens 26₁₄The fifth core layer 6_FiveCondensed on the end face of
[0071]
5 core layers 6₁~ 6_FiveThe laser light reflected by each end face of the light is guided through the planar optical waveguide including each core layer, and is diffracted by the hologram recorded in each planar optical waveguide. Five hologram images are formed on the 18 light receiving surfaces. The reproduced hologram images are respectively detected by the light detection means 18. That is, the five core layers 6₁~ 6_FiveAre simultaneously selected, and information recorded as a hologram on the planar optical waveguide including each core layer is simultaneously reproduced.
[0072]
The point that the core layer on which the laser beam is incident can be switched by controlling the surface emitting laser on / off by the drive control means 24 is the same as in the first embodiment, and thus the description thereof is omitted.
[0073]
As described above, the hologram reproducing apparatus according to this embodiment turns on and off each of the light sources of the illuminating device to guide the illuminating light from a plurality of stacked planar optical waveguides of the hologram recording medium. Two or more planar optical waveguides can be selected, and any hologram (information) recorded in each planar optical waveguide can be selectively reproduced. In addition, when a plurality of holograms are recorded on one planar optical waveguide, each hologram can be reproduced by making a laser beam incident on each recording area.
[0074]
Further, the planar optical waveguide from which information is read can be switched by on / off control of the light source without using a mechanical driving means, and information can be read at high speed and with high accuracy.
[0075]
In addition, since the light source column in each row of the illumination light source corresponds to each of the planar optical waveguides, illumination light having a different phase for each planar optical waveguide can be incident and recorded in a plurality of planar optical waveguides. Even if the information is played back simultaneously, crosstalk does not occur.
[0076]
Further, the coupling optical system can be made compact by forming the microlens directly above the opening of each surface emitting laser of the illumination device.
[0077]
Further, since the light is introduced from the vertical direction, a medium structure in which a plurality of the above-described media are bonded in the direction of the optical waveguide layer is possible, and the recording amount in the planar direction can be increased.
[0078]
The hologram reproducing apparatus according to the first to fifth embodiments can be any hologram recording medium that reproduces information recorded by guiding light through the laminated planar optical waveguide. Information can be reproduced even from such a recording medium.
[0079]
For example, it is possible to use a hologram recording medium in which a material that exhibits light-induced birefringence and is held at room temperature is used for the optical waveguide layer. As such a material, a polymer having a photoisomerizable group in the side chain can be used. In addition, the photoisomerizable group preferably includes, for example, an azobenzene skeleton.
[0080]
The principle of light-induced birefringence will be described using azobenzene as an example. As shown below, azobenzene repeats a trans-cis-trans isomerization cycle by irradiation with light.
[0081]
[Chemical 1]

[0082]
Before the light irradiation, a large amount of trans azobenzene exists in the optical waveguide layer (optical recording layer). These molecules are randomly oriented and are isotropic in macro. When irradiated with certain linearly polarized light, azo molecules having an absorption axis in the same direction are selectively isomerized from the trans form to the cis form. The cis isomer is isomerized to the trans isomer again because it is thermally unstable, but the molecule relaxed to the trans isomer having an absorption axis perpendicular to the polarization direction no longer absorbs light and is fixed in that state. As a result of this trans-cis-trans isomerization cycle, anisotropy of absorption coefficient and refractive index, that is, dichroism and birefringence are induced in a macro view. A polymer containing such a photoisomerization group can change the orientation of the polymer itself by photoisomerization and induce a large birefringence. The birefringence induced in this way is stable below the glass transition temperature of the polymer and is suitable for hologram recording.
[0083]
Polyester having cyanoazobenzene in the side chain represented by the following general formula described in JP-A-10-340479 can be recorded on a hologram by the mechanism described above.
[0084]
[Chemical 2]

[0085]
This polyester can record a hologram at room temperature, and the recorded hologram is held semipermanently. Furthermore, this polyester can record an intensity modulation hologram and a polarization modulation hologram at the same time, and since their diffraction efficiencies are equal, it is also possible to record a hologram in a polarization state. Therefore, the polyester represented by the above general formula is suitable for the optical waveguide layer.
[0086]
The hologram reproducing apparatus can also be used for reproducing the hologram recording medium described in JP-A-9-101735 and JP-A-11-345419. A recording medium described in Japanese Patent Application Laid-Open No. 9-101735 includes a plurality of optical waveguides having a substrate and a waveguide layer, and a part or all of the optical waveguide is an optical recording material (specifically, a photochromic material such as bacteriorhodopsin) ). Information recorded by the optical recording material can be read out using evanescent light of light guided through the optical waveguide. In addition, in the recording medium described in JP-A-11-345419, information is recorded on at least one of the core layer and the cladding layer in each waveguide by a periodic scattering factor having a period substantially equal to the period of the waveguide mode. ing.
[0087]
In the first to fifth embodiments, the reproduction light from all the holograms is detected by the same light detection means. However, the light is divided into a plurality of blocks and a plurality of lights corresponding to the respective blocks. It is good also as a structure which detects the reproduction light from a some hologram by a detection means.
[0088]
In the first to fifth embodiments described above, the example in which the surface emitting laser array in which the surface emitting lasers are arranged in a matrix of 5 rows and 4 columns is used for the illumination device has been described. In addition, a surface emitting laser array in which surface emitting lasers (light sources) are arranged one-dimensionally in the stacking direction may be used as an illumination device. In this case as well, an arbitrary planar optical waveguide can be selected from a plurality of planar optical waveguides on which hologram recording media are stacked, by using on / off control of each surface emitting laser, without using mechanical driving means. . In addition, the illumination device is moved along the in-plane direction of the planar optical waveguide using a driving unit such as an actuator, or the laser light from each light source is moved to the planar optical waveguide using a scanning optical system such as a galvanometer mirror. By using a mechanical driving means together, such as scanning along the in-plane direction, laser light can be incident from different positions on the end face of the same planar optical waveguide. Note that the hologram recording medium may be moved instead of moving the illumination device.
[0089]
【The invention's effect】
  According to the information reproducing apparatus of the present invention, information recorded on each planar optical waveguide from a hologram recording medium in which a plurality of planar optical waveguides on which holograms are recorded is laminated without using mechanical driving means. It is possible to selectively reproduce the image. Further, since the planar optical waveguide for reproducing information can be switched without using a mechanical driving means, information can be read at high speed and with high accuracy.Also, since the laser light from the light source is focused in the vertical direction and is not focused in the horizontal direction, it is incident on the planar optical waveguide, so that the light intensity in the planar optical waveguide is made uniform and efficient. Information can be read out.Furthermore, since illumination light is incident from light sources arranged corresponding to each of the planar optical waveguides, illumination light having a different phase can be incident on each planar optical waveguide, and information can be reproduced without crosstalk. Can do.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic configuration of a hologram recording medium.
FIG. 2 is a perspective view showing a schematic configuration of the hologram reproducing apparatus according to the first embodiment.
3A and 3B are side views of the hologram reproducing apparatus according to the first embodiment, and FIG. 3C is a plan view as viewed from above.
4A is a perspective view showing a partial configuration of an illumination device in which a microlens is directly formed, and FIG. 4B is a perspective view showing a schematic configuration of a hologram reproducing device according to a second embodiment. is there.
FIG. 5 is a side view of a hologram reproducing device according to a second embodiment.
FIG. 6 is a perspective view showing a schematic configuration of a hologram reproducing apparatus according to a third embodiment.
FIG. 7 is a side view of a hologram reproducing device according to a third embodiment.
FIG. 8 is a plan view seen from above of a hologram reproducing apparatus according to a third embodiment.
FIG. 9 is a perspective view showing a schematic configuration of a hologram reproducing apparatus according to a fourth embodiment.
FIG. 10 is a side view of a hologram reproducing device according to a fourth embodiment.
FIG. 11 is a plan view seen from above of a hologram reproducing device according to a fourth embodiment.
FIG. 12 is a perspective view showing a schematic configuration of a hologram reproducing apparatus according to a fifth embodiment.
FIG. 13 is a side view of a hologram reproducing device according to a fifth embodiment.
[Explanation of symbols]
6 Core layer (optical waveguide layer)
8 Clad layer
10 Hologram recording medium
12, 12A Lighting device
14 Collimating lens
16 Condensing lens
18 Light detection means
20 Imaging optical system
22 Light source (surface emitting laser)
24 Drive control means
26₁₁~ 26₅₄  Micro lens
28 Micro lens array
30₁₁~ 30₅₄  Micro lens
32 Lenticular lens
34₁~ 34_FiveCylindrical lens
36, 38 Cylindrical lens

Claims (6)

An information reproducing apparatus for reproducing information recorded on a planar optical waveguide from a hologram recording medium in which a plurality of planar optical waveguides on which information is recorded by a hologram are laminated, with light guided through the planar optical waveguide Because
A plurality of light sources that can be independently turned on / off and arranged corresponding to each of the planar optical waveguides, and illuminating means for illuminating the hologram recording medium with illumination light from the light sources;
In order to correspond to a plurality of light sources arranged corresponding to the plurality of planar optical waveguides, a curvature is provided in the laminating direction of the planar optical waveguides of the hologram recording medium and a curvature is orthogonal to the laminating direction. A plurality of lenses that are not arranged in the stacking direction, a condensing optical system that collects illumination light from the light source in the stacking direction and enters the corresponding planar optical waveguide;
An information reproducing apparatus comprising:   The information reproducing apparatus according to claim 1, further comprising detection means for detecting a hologram image reproduced by guiding illumination light through the planar optical waveguide. The information reproducing apparatus according to claim 1, wherein the illumination unit is a laser array in which a plurality of surface emitting lasers are monolithically formed on the same substrate. The information reproducing apparatus according to claim 3, wherein the plurality of surface emitting lasers are laser arrays arranged in a staggered manner. 5. The information reproducing apparatus according to claim 3, further comprising a microlens array formed of a plurality of microlenses having a collimating function, which is formed on an emission opening surface of each of the plurality of surface emitting lasers. The information reproducing apparatus according to claim 1, wherein the condensing optical system determines a focal length of each lens in accordance with a position where the illumination light is incident on the planar optical waveguide.

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