JP2006251355A - Information reproducing apparatus and information reproducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information reproducing apparatus and an information reproducing method capable of performing the alignment of an information recording medium and a mask aperture highly precisely at a high speed and improving an information processing speed. <P>SOLUTION: The information reproducing apparatus 10A drives an X-Y biaxial stage, as a first step, to move an integrated imager 11 and liquid crystal mask 12 to a region desired to be reproduced (a portion where diffracted light Fa is emitted) of a hologram information recording medium 50. Thereby, the diffracted light Fa is detected in a photodetector in the imager 11 and rough positioning is performed. Next, the information reproducing apparatus 10A controls switching of the transmission and shut off of the light in the liquid crystal mask 12, as a second stage, thereby performing micronic positioning. As a result, the aperture 15a is finely adjusted to the position of the aperture intrinsically ought to exist with respect to a hologram 20a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an information reproducing apparatus and an information reproducing method, and more particularly to an information reproducing apparatus and an information reproducing method for reproducing information recorded on a multiple hologram recording medium.

  Conventionally, a magnetic card such as a telephone card has been generally used as an information card that can be carried in a pocket. In recent years, IC (Integrated Circuit) cards have appeared in addition to magnetic cards, and application to electronic commerce is considered. However, although magnetic cards are inexpensive, there is a high risk of information deterioration or counterfeiting due to external magnetization. An IC card is highly secure and difficult to counterfeit, but the cost per sheet is high, and the bit price is high as an information recording medium.

  In order to overcome such a problem, a planar waveguide hologram information recording medium has been devised in which a planar single-mode optical waveguide including a diffraction grating for generating a hologram image is laminated in multiple layers. The planar waveguide hologram information recording medium is described in detail in Patent Documents 1 to 3, and will be briefly introduced below.

  A planar single mode optical waveguide is a so-called slab optical waveguide in which a plate-like transparent medium such as quartz or plastic is used as a core layer, and a medium having a lower refractive index is sandwiched from both sides as a cladding layer. The slab optical waveguide can propagate light in the in-plane direction by confining light in the core layer, and is applied to components for optical communication such as a semiconductor laser. The planar waveguide hologram information recording medium is characterized in that the slab optical waveguides are stacked in layers and each waveguide layer has a hologram.

  FIG. 8 is a cross-sectional view showing the configuration of a conventional information reproducing apparatus 100 that reproduces information from a planar waveguide hologram information recording medium 500. The information reproducing apparatus 100 includes an image sensor 110, a mask 120 having an opening 150, and a cylindrical lens 17.

  The hologram information recording medium 500 has a structure in which a clad layer and a core layer having a refractive index higher than that of the clad layer are alternately laminated, and a 45-degree reflection mirror 18 is formed on the end face. Information is recorded as a scattering factor (hologram) 200 in the waveguide layer 23 which is one of the core layers. The hologram 200 is formed in advance by a method such as modulating the refractive index. Information is recorded on the information recording medium 500 by a multiplexing method having areas in which holograms that diffract independent independent reproduction images overlap each other.

  Referring to FIG. 8, a planar light wave PL emitted from a light source (not shown) is collected by a cylindrical lens 17 as a linear beam PF having a cylindrical wavefront on a 45-degree reflection mirror 18. The linear beam PF is reflected by the 45-degree reflection mirror 18 and is coupled to the waveguide layer 23 to become the guided light PW. The guided light PW is scattered by the hologram 200 formed in the waveguide layer 23 and is emitted from the upper surface of the hologram information recording medium 500 as diffracted light DF.

  Most of the diffracted light DF is blocked by the mask 120 disposed above the hologram information recording medium 500. A reproduced image to be combined on the image sensor 110 is selected by the opening 150 provided in the mask 120. Thus, the mask 120 functions as a spatial light modulator. Further, as shown in FIG. 8, the reproduced image is larger than the opening 150 of the mask 120. The information reproducing apparatus 100 can combine different images for each core layer by diffraction of the guided light PW coupled to the waveguide layer 23.

  FIG. 9 is a top perspective view showing a configuration of a conventional information reproducing apparatus 100 that reproduces information on a planar waveguide type hologram information recording medium 500. However, the image sensor 110 is not shown. As shown in FIG. 9, the size of the hologram 200 that creates the wavefront of the opening 150 is larger than the opening 150 of the mask 120. Therefore, the diffracted light DFt that passes through the opening 150 includes only the information of the hologram 200.

  With reference to FIG. 8, the information reproducing apparatus 100 can change the position where the linear beam PF is condensed by moving the cylindrical lens 17 in the X direction. As a result, it is possible to individually read out information recorded in each of the laminated waveguide layers by changing the waveguide layer to which the planar lightwave PL is coupled. In this way, by arranging the mask 120 between the hologram information recording medium 500 and the image sensor 110 and changing the opening pattern of the openings 150 of the mask 120, images to be combined on the image sensor 110 one by one. Can be separated and regenerated.

  As shown in FIG. 9, in the information reproducing apparatus 100, the entire hologram information recording medium 500 is covered with a mask 120, and a mask 120 having almost the same size as the hologram information recording medium 500 is required. In addition, the information reproducing apparatus 100 needs to change the opening pattern of the opening 150 of the mask 120 every time one image is reproduced. As a result, the information reproducing apparatus 100 has a problem of high cost.

  To solve the above problem, it is conceivable to reduce the size of the mask 150 to such an extent that diffracted light from other than the hologram to be reproduced does not enter the image sensor 110. When the size of the mask 150 is reduced, in order to read all the information recorded on the hologram information recording medium 500, it is necessary to read the information by moving the mask on the hologram information recording medium 500. At this time, it is important to accurately move the opening 150 and the image sensor 110 to an arbitrary position where information to be read is recorded.

  When the positions of the opening 150 and the image sensor 110 are shifted, a plurality of hologram images are overlapped, and the reproduced image is deteriorated. This is referred to as crosstalk, but in order to reduce crosstalk, it is necessary to accurately control the positional relationship between the opening 150 and the hologram information recording medium 500. In order to accurately control these positional relationships, a method of moving the mask and the image sensor while detecting positional information is employed.

  As one of position control methods by detecting position information of a mask and an image sensor, there is a method described in Patent Document 3. In this method, a hologram for information recording and a hologram for alignment are formed in one waveguide hologram. The alignment hologram is designed to selectively diffract and collect light in one direction.

The light diffracted by the alignment hologram is controlled using a photodetector such as a two-dimensional optical array detector or a light spot position detection element. Specifically, it is detected where the condensing point is located on the photodetector, and the mask and the image sensor are moved in parallel to a predetermined position. Thereby, the positional relationship between the mask opening and the information recording medium is accurately controlled.
JP-A-11-345419 Japanese Patent Laid-Open No. 2001-210088 JP 2001-52128 A

  As a means for moving the mask and the image sensor, a mechanical driving method using a stepping motor or the like can be considered. However, when a mechanical driving method is used, a driving method using two controls of coarse position adjustment and fine position adjustment must be taken for each position control. In this case, there is a problem that the structure of the control device becomes large and complicated. In addition, there is a problem that the information processing speed is slowed down because the drive time of the device required for position control is required.

  Further, when reading information in an arbitrary area and then reading information recorded in the adjacent area, the mask and the image sensor are moved again onto the recording area to be read out of the adjacent information recording medium, and the mask It is necessary to align the opening and the information recording medium. When a plurality of pieces of information are sequentially read in this way, it is necessary to adjust the position of the mask opening and the information recording medium for each area. In this case, since it takes time to adjust the position for each region, there is a problem that the information processing speed is further reduced.

  The present invention has been made in view of the above circumstances, and an information reproducing apparatus and an information reproducing method capable of accurately and rapidly aligning an information recording medium and a mask opening and improving an information processing speed. The purpose is to provide.

  The present invention relates to an information reproducing apparatus for reproducing information recorded on a planar waveguide type information recording medium in which a scattering factor is formed in a waveguide layer, and makes light incident on the waveguide layer of the information recording medium. An optical system, a mask that partially shields light scattered by a scattering factor while propagating through a waveguide layer, and an imaging device that receives a hologram image of reproduction light emitted through an opening of the mask. The imaging device includes a photodetector that detects light scattered from the alignment scattering factor included in the scattering factor. The information reproducing apparatus moves the opening from the predetermined position of the scattering factor to an adjacent position by moving the opening of the mask by electrical control based on the detection result from the photodetector.

  Preferably, the apparatus further includes a two-axis stage that roughly adjusts a predetermined position of the scattering factor by moving the mask by mechanical control based on the detection result from the photodetector.

  Preferably, the information reproducing apparatus adjusts the predetermined position of the scattering factor more accurately by performing a fine position adjustment in which the opening of the mask is moved by electrical control after the coarse position adjustment by the biaxial stage. Identify.

  Preferably, the information reproducing apparatus performs fine position adjustment by electrically moving the opening of the mask in units of pixels.

  Preferably, the mask has the same size as the image sensor and is integrally formed with the image sensor.

  Preferably, the mask is a spatial light modulator using liquid crystal.

  Preferably, the mask is a spatial light modulator using a magnetic material.

  According to another aspect of the present invention, there is provided an information reproducing method for reproducing information recorded on a planar waveguide type information recording medium in which a scattering factor is formed in a waveguiding layer, the information reproducing method comprising: Receiving light on the layer, partially shielding the light scattered by the scattering factor while propagating through the waveguide layer with a mask, and receiving a hologram image of the reproduction light emitted through the opening of the mask And a step of performing. The step of receiving the hologram image includes a detection step of detecting light scattered from the alignment scattering factor included in the scattering factor, and moving the opening of the mask by electrical control based on the detection result of the detection step. And a moving step of moving the opening from a predetermined position of the scattering factor to an adjacent position.

  Preferably, the moving step includes a rough position adjusting step for roughly adjusting a predetermined position of the scattering factor by moving the mask by mechanical control based on the detection result of the detecting step, and the opening of the mask is electrically connected. And a minute position adjusting step for more accurately specifying a predetermined position of the scattering factor by moving the light by such control.

  Preferably, in the fine position adjustment step, the opening of the mask is electrically moved in units of pixels.

  According to the present invention, it is possible to improve the information processing speed by positioning the information recording medium and the mask opening accurately and at high speed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a sectional view showing the structure of an information reproducing apparatus 10A according to Embodiment 1 of the present invention. The information reproducing apparatus 10A according to the first embodiment includes an imaging element 11, a liquid crystal mask 12 having an opening 15a, and a cylindrical lens 17. The image sensor 11 is, for example, a CMOS (Complementary Metal-Oxide-Semiconductor) sensor. The liquid crystal mask 12 may be a spatial light modulator using a magnetic material, for example, besides using liquid crystal.

  A spatial light modulator using a magnetic material is made of a magneto-optical material and utilizes the magneto-optical effect of the magnetic material. The mask by the spatial light modulator is formed by a plurality of pixels that can be controlled independently in the direction of magnetization.

  In a spatial light modulator using the magneto-optic effect, the direction of magnetization in each pixel changes due to the Faraday effect. Accordingly, the spatial light modulator rotates the polarization direction of light passing through each pixel by a predetermined angle in opposite directions. Therefore, it is possible to generate spatially modulated light by controlling the direction of magnetization in each pixel.

  The spatial light modulator using the magneto-optic effect is common to the liquid crystal spatial light modulator in that optical rotation is used, but is different in the following points, for example.

  First, the response speed is several n seconds, which is 1000 times faster than the high-speed liquid crystal, which is about 10 μs. Second, the image resolution can be easily increased to 1000 dpi or more. Thirdly, the bag function (liquid sealing with a glass plate, a plastic plate, etc.) for preventing liquid leakage is unnecessary. Fourthly, a part of the pixel does not become unusable due to a transistor or the like for switching the state of the pixel.

  As described above, the spatial light modulator using the magneto-optical effect is superior to the liquid crystal spatial light modulator in several respects. However, in the embodiment of the present invention, a liquid crystal mask is used as an example.

  The information reproducing apparatus 10A reproduces information recorded on the hologram information recording medium 50. The hologram information recording medium 50 is a removable medium that can be removed from the information reproducing apparatus 10A and carried.

  The hologram information recording medium 50 has an optical waveguide structure in which a clad layer and a core layer having a refractive index higher than that of the clad layer are alternately laminated. The refractive index of the core layer is preferably higher than that of all the cladding layers, but this is not necessarily the case. For example, the refractive index of each core layer must be higher than adjacent cladding layers, but may be lower than non-adjacent cladding layers.

  The hologram information recording medium 50 has a substantially rectangular parallelepiped shape, and a 45-degree reflection mirror 18 with a core layer and a cladding layer exposed to the outside is formed on the end face. The core layer of the hologram information recording medium 50 forms a planar single mode waveguide layer.

  Information is recorded as a scattering factor (hologram) 20a in the waveguide layer 23 which is one of the core layers. The hologram 20a is formed in advance by a method such as modulating the refractive index. Information is recorded on the information recording medium 50 by a multiplexing method having areas in which holograms that diffract independent independent reproduction images overlap each other.

  Referring to FIG. 1, a planar light wave PL emitted from a light source (not shown) is collected by a cylindrical lens 17 as a linear beam PF having a cylindrical wavefront on a 45-degree reflection mirror 18. The linear beam PF is reflected by the 45-degree reflection mirror 18 and is coupled to the waveguide layer 23 to become the guided light PW. The guided light PW propagates in the waveguide layer 23 in the direction parallel to the layer and is scattered by the hologram 20 a formed in the waveguide layer 23. The scattered light is emitted from the upper surface of the hologram information recording medium 50 as diffracted light DF.

  Here, the diffracted light DF is obtained by overlapping the diffracted lights DFa to DFc by the hologram formed for each of the plurality of regions of the core layer. In order to reproduce only the desired diffracted light DFa from the diffracted light DFa to DFc, etc., as shown in FIG. 1, the opening 15a of the image sensor 11 and the liquid crystal mask 12 is moved to the portion where the diffracted light DFa is condensed. Let

  In the information reproducing apparatus 10A of the first embodiment, the image sensor 11 and the liquid crystal mask 12 are integrated, and move on the hologram information recording medium 50 as a unit. By moving the aperture 15a of the image sensor 11 and the liquid crystal mask 12 to a portion where the diffracted light DFa is condensed, the diffracted lights DFb and DFc diffracted from the surrounding hologram are blocked by the liquid crystal mask 12. Therefore, only the information to be reproduced is included in the diffracted light DFa transmitted from the opening 15 a of the liquid crystal mask 12 and is taken into the image sensor 11.

  FIG. 2 is a top perspective view showing the configuration of the information reproducing apparatus 10A according to Embodiment 1 of the present invention. However, the image sensor 11 is not shown. As shown in FIG. 2, the liquid crystal mask 12 of the information reproducing apparatus 10A of Embodiment 1 is smaller than the mask 120 of the conventional information reproducing apparatus 100 shown in FIG. Therefore, as shown in FIG. 1, the diffracted light blocked by the liquid crystal mask 12 is only diffracted light DFb, DFc diffracted from the hologram around the hologram 20a, and the diffracted light from other parts is not blocked.

  However, in the information reproducing apparatus 10 </ b> A according to the first embodiment, the size of the image sensor 11 is reduced to the same extent in accordance with the size of the liquid crystal mask 12. Therefore, as shown in FIG. 1, the diffracted light that is not shielded by the liquid crystal mask 12 does not enter the image sensor 11, and only the diffracted light DFt that has passed through the opening 15 a of the liquid crystal mask 12 reaches the image sensor 11. Therefore, the diffracted light that is not shielded by the liquid crystal mask 12 is not read out by the image sensor 11.

  Referring to FIG. 1, information reproducing apparatus 10A can change the position where linear beam PF is condensed by moving cylindrical lens 17 in the XY directions. As a result, it is possible to individually read out information recorded in each of the laminated waveguide layers by changing the waveguide layer to which the planar lightwave PL is coupled.

  As described above, the information reproducing apparatus 10A according to the first embodiment moves the opening 15a of the liquid crystal mask 12 to the area (hologram 20a) to be reproduced on the hologram information recording medium 50, and the information recorded on the hologram 20a is transferred. Only the diffracted light DFa is selectively passed through the opening 15a of the liquid crystal mask 12. As a result, a hologram image for the region desired to be reproduced on the hologram information recording medium 50 is formed on the imaging surface. By capturing this hologram image with the image pickup device 11, information recorded as the hologram 20 a on the waveguide layer 23 of the hologram information recording medium 50 can be read.

  In order to accurately read the information, when the opening 15a of the liquid crystal mask 12 is moved to the region to be reproduced on the hologram information recording medium 50, the opening 15a and the hologram information recording medium 50 are accurately aligned. It becomes important.

  In the information reproducing apparatus 10A of the first embodiment, when the alignment between the opening 15a and the hologram information recording medium 50 is shifted or when the alignment is not performed, the hologram image is not accurately observed. In this case, since the diffracted beams DFb and DFc including information recorded in the neighboring area are reproduced as crosstalk, a plurality of hologram images are overlapped and read into the image sensor 11. Next, accurate alignment between the opening 15a and the hologram information recording medium 50 in the information reproducing apparatus 10A will be described.

  Referring to FIG. 1, a hologram for positioning is formed on hologram 20a of hologram information recording medium 50 in addition to an information recording hologram. The alignment hologram is recorded so as to be condensed at one point to form a spot. When the guided light PW is diffracted, spherical diffraction light is generated. The image sensor 11 includes a photodetector such as a two-dimensional optical array detector or a light spot position detector (PSD) in order to detect diffracted light diffracted by the alignment hologram.

  At the time of information reproduction, the information reproduction apparatus 10A detects where the alignment hologram spot is located on the photodetector. In the information reproducing apparatus 10A, the image sensor 11 and the liquid crystal mask 12 are fixed on a biaxial stage (not shown) capable of XY biaxial translation. The information reproducing apparatus 10A performs alignment by translating the image sensor 11 and the liquid crystal mask 12 based on the detected position information.

  Hereinafter, the reading operation of the hologram image in the information reproducing apparatus 10A of Embodiment 1 will be described in detail.

  First, as a first stage, the information reproducing apparatus 10A drives the XY biaxial stage, and the imaging element 11 integrated with a region (a portion where the diffracted light DFa is emitted) to be reproduced of the hologram information recording medium 50 is integrated. Then, the liquid crystal mask 12 is moved. Thereby, the diffracted light DFa is detected by the photodetector in the image pickup device 11, and the coarse position is adjusted.

  FIG. 3 is a perspective top view for explaining coarse position adjustment of the information reproducing apparatus 10A according to the first embodiment of the present invention. However, the image sensor 11 is not shown. As shown in FIG. 3, in the coarse position adjustment stage, the opening 15a of the liquid crystal mask 12 is generally slightly shifted in the XY axis direction from the position of the opening 15ac that should be originally located with respect to the position of the hologram 20a. In this state, the reproduced hologram image includes crosstalk in which the diffracted light DFb and DFc including information recorded in the neighboring area are overlapped in addition to the diffracted light DFa.

  In order to eliminate the crosstalk as described above, next, as a second stage, the information reproducing apparatus 10A performs minute position adjustment. FIG. 4 is a transparent top view for explaining the minute position adjustment of the information reproducing apparatus 10A according to the first embodiment of the present invention. However, the image sensor 11 and the hologram 20a are not shown.

  As shown in FIG. 4, the liquid crystal mask 12 includes pixels PX formed in a lattice shape that can control transmission and blocking of light. Switching between transmission and blocking of light in the liquid crystal mask 12 is performed by electrically controlling the liquid crystal mask 12 for each pixel PX. In the liquid crystal mask 12, the opening 15a is controlled to transmit light, and the other portions are controlled to block light. The shape of the opening 15 a can be freely changed according to the electrical control of the liquid crystal mask 12.

  The information reproducing device 10A electrically controls each pixel PX of the liquid crystal mask 12 without using a mechanical driving method with a two-axis stage in fine position adjustment. The information reproducing apparatus 10A controls the opening 15a through which light is transmitted to the position of the opening 15ac that should be originally located with respect to the hologram 20a by moving the position of the opening 15a in two directions in the XY plane.

  The alignment accuracy of the opening 15a by the pixel control depends on the size of the pixel PX of the liquid crystal mask 12, and is approximately 7 to 15 μm. Even in the case where the alignment has to be performed by rotating the opening 15a on the XY plane, the pixel PX can be electrically controlled so that the opening 15a rotates.

  In the moving operation of the opening 15a, the information reproducing apparatus 10A detects the diffracted light diffracted from the alignment hologram included in the hologram 20a by the photodetector of the imaging element 11. The information reproducing apparatus 10A searches for the position of the opening 15ac at which the crosstalk of the hologram image is minimized while reading the signal detected by the photodetector.

  In this way, the information reproducing apparatus 10A performs fine position adjustment by moving the opening 15a of the liquid crystal mask 12 only by control by an electric circuit and without using a mechanical driving method. As a result, fine position adjustment can be performed in a time of several tens of microseconds, which is the scanning speed of the liquid crystal. Therefore, the position of the opening 15a can be adjusted in a shorter time than when the fine position adjustment is performed by mechanical means. As a result, the information processing speed is increased.

  As described above, according to the first embodiment, the size of the liquid crystal mask 12 is reduced by performing the electrical fine position adjustment after the mechanical coarse position adjustment in the alignment between the information recording medium and the mask opening. It can be made as small as the image sensor 11. As a result, the information processing speed of the information reproducing apparatus can be improved, the size of the information reproducing apparatus can be reduced, and the cost can be reduced.

[Embodiment 2]
The information reproducing apparatus 10A according to the first embodiment reads information from the hologram information recording medium 50 by moving the opening 15a of the liquid crystal mask 12 to the hologram 20a that is an area to be reproduced. In the second embodiment, a case where information recorded in a peripheral area adjacent to the hologram 20a is read following the reading operation of the hologram 20a will be described.

  FIG. 5 is a sectional view showing the structure of an information reproducing apparatus 10B according to Embodiment 2 of the present invention. The information reproducing apparatus 10B according to the second embodiment reads information on the hologram 20c adjacent to the hologram 20a from which information is read in the first embodiment. The diffracted light DFc diffracted from the hologram 20 c is selectively read into the image sensor 11 through the opening 20 c of the liquid crystal mask 12. Next, accurate alignment between the opening 15c and the hologram information recording medium 50 in the information reproducing apparatus 10B will be described.

  FIG. 6 is a top perspective view showing a configuration of an information reproducing apparatus 10B according to Embodiment 2 of the present invention. However, the image sensor 11 is not shown. As shown in FIG. 6, the information reproducing apparatus 10B has an opening 15ac in which the crosstalk of the hologram image specified in the first embodiment can be minimized. Move to opening 15cc.

  FIG. 7 is a perspective top view for explaining position adjustment for moving the opening 15ac of the information reproducing apparatus 10B according to Embodiment 2 of the present invention to the opening 15cc. However, the image sensor 11 and the hologram 20c are not shown. Now, since the distance between the opening 15ac and the opening 15cc is determined in advance according to the standard of the hologram information recording medium 50, the moving distance from the opening 15ac to the opening 15cc is determined in advance by pixel control. It is possible to program.

  Therefore, as shown in FIG. 7, in the information reproducing device 10B of the second embodiment, when the opening 15ac is moved to the adjacent opening 15cc, only a predetermined number of pixels (24 pixels in FIG. 7) are controlled by pixel control. It is only necessary to move the opening 15ac. In other words, the information reproducing apparatus 10B in which the position of the opening 15ac where the crosstalk of the hologram image is minimized is specified, and the coarse position adjustment and the minute position are used to move the opening 15ac to the adjacent opening 15cc. Two-stage position adjustment such as adjustment is not necessary.

  Therefore, the information reproducing apparatus 10B can read the information of the hologram 20c adjacent to the hologram 20a in a time of about several tens of microseconds which is the scanning speed of the liquid crystal, and as a result, the information processing speed is increased.

  As described above, according to the second embodiment, when the opening 15ac in which the crosstalk of the hologram image is suppressed to the minimum is moved to the adjacent opening 15cc or the like, the openings are provided by a predetermined number of pixels by pixel control. It is only necessary to move 15ac. Thereby, the information processing speed of the information reproducing apparatus can be further improved.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

It is sectional drawing which showed the structure of 10 A of information reproduction apparatuses by Embodiment 1 of this invention. 1 is a top perspective view showing the configuration of an information reproducing apparatus 10A according to Embodiment 1 of the present invention. It is a see-through | perspective top view for demonstrating the coarse position adjustment of 10 A of information reproduction apparatuses by Embodiment 1 of this invention. It is a transparent top view for demonstrating the fine position adjustment of 10 A of information reproducing apparatuses by Embodiment 1 of this invention. It is sectional drawing which showed the structure of the information reproduction apparatus 10B by Embodiment 2 of this invention. It is the upper surface perspective view which showed the structure of the information reproduction apparatus 10B by Embodiment 2 of this invention. It is a see-through | perspective top view for demonstrating the position adjustment which moves the opening part 15ac of the information reproducing apparatus 10B by Embodiment 2 of this invention to the opening part 15cc. 1 is a cross-sectional view showing a configuration of a conventional information reproducing apparatus 100 that reproduces information from a planar waveguide hologram information recording medium 500. FIG. 1 is a top perspective view showing a configuration of a conventional information reproducing apparatus 100 that reproduces information of a planar waveguide hologram information recording medium 500. FIG.

Explanation of symbols

  10A, 10B, 100 Information reproducing device, 11, 110 Image sensor, 12 Liquid crystal mask, 15a, 15ac, 15c, 15cc, 150 Aperture, 17 Cylindrical lens, 1845 degree reflection mirror, 23 Waveguide layer, 50, 500 Hologram Information recording medium, 120 mask, 20a, 20c, 200 hologram.

Claims (10)

An information reproducing apparatus for reproducing information recorded on a planar waveguide type information recording medium in which a scattering factor is formed in a waveguide layer,
An optical system for making light incident on the waveguide layer of the information recording medium;
A mask that partially shields light scattered by the scattering factor during propagation through the waveguide layer;
An image sensor for receiving a hologram image of the reproduction light emitted through the opening of the mask,
The imaging device includes a photodetector that detects light scattered from the alignment scattering factor included in the scattering factor,
The information reproducing apparatus moves the opening of the mask from a predetermined position of the scattering factor to an adjacent position by moving the opening of the mask by electrical control based on the detection result from the photodetector. An information reproducing apparatus.   The information according to claim 1, further comprising a biaxial stage that coarsely adjusts the predetermined position of the scattering factor by moving the mask by mechanical control based on a detection result from the photodetector. Playback device.   The information reproducing apparatus adjusts the predetermined position of the scattering factor by performing a fine position adjustment by moving the opening of the mask by electrical control after performing the coarse position adjustment by the biaxial stage. The information reproducing apparatus according to claim 2, wherein the information reproducing apparatus is specified accurately.   The information reproducing apparatus according to claim 3, wherein the information reproducing apparatus performs the minute position adjustment by electrically moving an opening of the mask in units of pixels.   The information reproducing apparatus according to claim 1, wherein the mask has the same size as the imaging element and is integrally formed with the imaging element.   The information reproducing apparatus according to claim 1, wherein the mask is a spatial light modulator using liquid crystal.   The information reproducing apparatus according to claim 1, wherein the mask is a spatial light modulator using a magnetic material. An information reproducing method for reproducing information recorded on a planar waveguide type information recording medium in which a scattering factor is formed in a waveguide layer,
Making light incident on the waveguide layer of the information recording medium;
Partially blocking by a mask light scattered by the scattering factor during propagation through the waveguide layer;
Receiving a hologram image of the reproduction light emitted through the opening of the mask,
The step of receiving the hologram image comprises:
A detection step of detecting light scattered from the scattering factor for alignment included in the scattering factor;
A moving step of moving the opening of the mask from a predetermined position of the scattering factor to an adjacent position by moving the opening of the mask by electrical control based on the detection result of the detection step. Playback method. The moving step includes
A coarse position adjusting step for roughly adjusting the predetermined position of the scattering factor by moving the mask by mechanical control based on the detection result of the detecting step;
The information reproducing method according to claim 8, further comprising: a fine position adjusting step of more accurately specifying the predetermined position of the scattering factor by moving the opening of the mask by electrical control.   The information reproducing method according to claim 9, wherein in the minute position adjusting step, the opening of the mask is electrically moved in units of pixels.

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