JP2006251340A - Recording medium reproducing apparatus using hologram and angle deviation adjusting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording medium reproducing apparatus using holograms to enable sure reading of data information recorded in multiplex on a recording medium page by page, and to provide an angle deviation adjusting method. <P>SOLUTION: A movable base 40 is moved by a tracking drive means to a position where the amount of light received in a main imaging element 55 gets maximal, and subsequently, the movable means 40 is moved to a position where any of photodetecting means 56 to 56 can detect at least one or more data light among a plurality of the data light. Next, the main imaging element 55 is moved by a focus drive means to the position where all the light detecting means 56a to 56d can receive the data light, respectively. Finally, when an angle deviation adjusting means 60 is driven, the spot of the data light is adjusted so as to move to the central position of the respective light detecting means 56a to 65a corresponding thereto. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a recording medium reproducing apparatus using a hologram for reading data information from a recording medium using a hologram, and an angle deviation adjusting method.

FIG. 9 is an explanatory diagram showing the principle of operation when recording and reproduction are performed using a hologram.
As shown in FIG. 9, at the time of recording, the first object light 1a including the recording data and the first reference light 2a are incident on the recording medium 3. At this time, since the first interference fringes 4a are formed by the two lights, the first interference fringes 4a representing the contents of the first object light 1a are recorded as the first page inside the recording medium 3. The

  On the other hand, when the first object beam 1a is not incident and only the first reference beam 2a is incident at the time of reproduction, the first interference fringe (first page) 4a is reproduced by the hologram principle and the first reproduction is performed. Light (diffracted light) 5a appears. Since the first reproduction light 5a at this time represents the same content as the first object light 1a recorded on the recording medium 3, an image sensor made up of a CCD, a CMOS, or the like is provided on the first reproduction light 5a. By arranging, the contents of the first page recorded on the recording medium 3 can be read out.

  Further, the second reference light 2b having an incident angle different from that of the first reference light 2a is incident on the recording medium 3 during recording, and the second reference light 2b having information different from that of the first object light 1a is input. When the second object light 1b is incident at the same incident angle as that of the first object light 1a, the second reference light 2b and the second object light 1b interfere with each other, and the second interference fringes 4b Two pages are formed. Therefore, the second page, which is the second interference fringe 4b, can be recorded in a superimposed manner in the same area as the position on the recording medium 3 where the first interference fringe 4a is recorded. When only the second reference light 2b is incident upon reproduction, the second reproduction light (diffracted light) 5b having the same information as the second interference fringe (second page) 4b appears. By using the image sensor, the contents of the second page recorded on the recording medium 3 can be read.

  That is, in the recording medium using the hologram, it is possible to multiplex-record two or more pieces of information for each page in the same recording area on the recording medium by using the above principle.

As a prior art using such a hologram, for example, the following Patent Document 1 exists.
JP 2001-93157 A

  The data recorded and reproduced using the hologram as described above is planar two-dimensional image data information, but the size of one pixel of the image sensor that reads the image data information is as small as about several μm to several tens of μm. For this reason, in order to read out data information (interference fringes) recorded on the recording medium 3, it is necessary to irradiate the recording medium 3 with reference light at a predetermined angle of incidence with extremely high accuracy. However, it is necessary to reliably capture the reproduction light (diffracted light) output from the recording medium 3 for each page.

  That is, a part constituting an optical system for reproduction, that is, a light emitting element such as a laser diode that emits reference light, an actuator (optical pickup) equipped with the imaging element and various lenses, and a record in which data information is recorded If the relative positional relationship with the medium 3 is not accurately adjusted for each page (interference fringe indicating data information), the SN ratio of the reproduced data signal is lowered, and each image data information cannot be read correctly. There's a problem.

  Such an actuator generally has both a tracking drive that is a horizontal alignment with respect to the recording medium 3 and a focusing drive that is a vertical alignment. It is difficult to set the relative positional relationship between the actuator and the recording medium with high accuracy only by moving in the vertical direction.

  The present invention is for solving the above-described conventional problems, and a recording medium reproducing apparatus using a hologram capable of reliably reading out data information for each page recorded in a multiplexed manner on a recording medium, and An object of the present invention is to provide a method for adjusting an angular deviation.

  The recording medium reproducing apparatus using the hologram of the present invention obtains reproducing light generated by diffracting the reference light by an interference fringe recorded on the recording medium, and a light emitting means that emits coherent light as reference light. Imaging means, a movable base on which the imaging means is mounted, an angle deviation adjusting means for adjusting an inclination angle of the imaging means, and the received light intensity of the reproduction light acquired by the imaging means is maximized. And a control means for controlling the angle deviation adjusting means.

  In the above, it is preferable that the light emitting unit and the imaging unit are mounted on the same movable base.

  Further, on the recording medium, page unit data information is recorded in multiple in a predetermined recording area, and each page is provided with two or more adjustment marks for detecting the received light intensity of the reproduction light. The movable base is provided with light detecting means for detecting data light generated due to the reference light being diffracted by the adjustment mark among the reproduction light.

  Further, the light detection means may be formed as a dedicated area in the imaging means allocated for each data light.

  Alternatively, the light detection means may be provided as a dedicated imaging means different from the imaging means.

  In the above, the angle deviation adjusting means is controlled so that two or more data lights move to a predetermined position of the corresponding light detecting means.

  Alternatively, the angle deviation adjusting means is controlled so that the spot diameters of the two or more data lights detected by the detecting means have a predetermined size.

  Furthermore, the angle deviation adjusting means is controlled so that the spot diameters of the two or more data lights detected by the light detecting means are equal to each other.

  Alternatively, the angle deviation adjusting means is controlled so that the spot diameter of the focal point of the data light is minimized.

  Further, the angle deviation adjusting means for adjusting the movable base can be a piezoelectric actuator utilizing distortion deformation of a piezoelectric element.

  Furthermore, the angle deviation adjusting means for adjusting the movable base can be an electromagnetic actuator using an electromagnetic force generated between a coil and a magnet.

  In the above, the movable base includes tracking drive means for moving the movable base in a horizontal direction in a plane parallel to the recording medium, and focusing drive for moving the movable base in a vertical direction perpendicular to the horizontal direction. Those provided with means are preferred.

The imaging means can be a CCD or CMOS image sensor.
In addition, the angle deviation adjusting method of the recording medium reproducing apparatus using the hologram of the present invention includes a light emitting unit that emits coherent light as reference light, and the reference light is diffracted by any of a plurality of interference fringes recorded on the recording medium. Imaging means for acquiring reproduced light generated by the operation, a movable base on which each means is mounted, an angle deviation adjusting means for adjusting an inclination angle of the imaging means, and the movable base as the recording medium Tracking drive means for moving in a horizontal direction within a parallel plane, focusing drive means for moving the movable base in a vertical direction perpendicular to the horizontal direction, control means for driving and controlling each means, and page unit Each page of the recording medium on which the data information is recorded in multiple is provided with two or more adjustment marks for detecting the light receiving intensity of the reproduction light. Ri, and a light detecting means for receiving a plurality of data light produced due to the adjustment marks of the reproducing light,
(1) a coarse tracking adjustment step of moving the movable base to a position where the amount of light received by the imaging means is maximized;
(2) a tracking fine adjustment step in which the light detection means moves the movable base to a position where at least one of the plurality of data lights can be received;
(3) a focus fine adjustment step of moving at least the imaging unit to a position where the light detection unit can receive all the data light, respectively;
(4) a tilt angle fine adjustment step of driving the angle deviation adjusting means so that each data light spot moves to a predetermined position of the light detecting means corresponding thereto;
It is characterized by having.

  Instead of the step (4), there may be a tilt angle fine adjustment step of driving the angle deviation adjusting means in which the spot diameters of the data light at two or more places have predetermined sizes, respectively.

  Alternatively, instead of the step (4), there may be a tilt angle fine adjustment step of driving the angle deviation adjusting means so that the spot diameters of the two or more data lights coincide with each other. it can.

  Alternatively, instead of the step (4), there is a tilt angle fine adjustment step of driving the angle deviation adjusting means so that the spot diameters of the data light at all locations are minimized. There may be.

  In the present invention, since the angular deviation of the actuator can be finely adjusted, the relative positional relationship between the actuator and the recording medium can be set with high accuracy. For this reason, the data information recorded in a multiplexed manner in the recording medium can be reliably read for each page.

  FIG. 1 is a sectional view schematically showing a recording medium reproducing apparatus using a hologram as an embodiment of the invention, FIG. 2 is a block diagram showing reproducing mechanism means for a recording medium mounted on a movable base, and FIG. 3 is imaging means. FIG. 4 is a plan view showing an example of two-dimensional image data information (hologram information) used in the embodiment of the present invention.

  A recording medium reproducing apparatus A shown in FIG. 1 includes a holding unit 10 that holds the recording medium 1 and a reproducing mechanism unit 20 provided above the holding unit 10.

  The holding means 10 differs depending on the type of the recording medium, but if the recording medium is a disc-shaped disk alone or a disk cartridge type, it is a disk driving means comprising a clamper, a turntable and a spindle motor. When the recording medium is planar such as a chip shape or a card shape, the operation is as follows.

  A holding means 10 shown in FIG. 1 has a base 11, wall surfaces 12 and 12, and a pair of upper plates 13 and 13 that are provided on the upper surfaces of the wall surfaces 12 and 12 and press the edge of the recording medium 1. An opening 10 </ b> A is formed between the upper plate 13 and the other upper plate 13.

  Biasing members 14 and 14 are provided in the base 11, and the recording medium 1 is urged in the Z1 direction in the figure while being placed on the urging members 14 and 14. In this state, both edge portions of the edge of the recording medium 1 are in contact with the lower surfaces of the pair of upper plates 13 and 13, and the surface of the recording medium 1 is directed in the Z1 direction through the opening 10A. Exposed.

  The regeneration mechanism means 20 has a holder 30 formed in a U-shaped cross section and a movable base 40 provided inside the holder 30. Legs 30A and 30B are provided at both ends in the X direction of the holder 30, and through holes 30a and 30b penetrating in the Y direction are formed in the leg portions 30A and 30B in parallel with each other. Yes.

  A female screw is threaded on the inner wall of one through hole 30a, and a screw shaft 31 having a male thread threaded on the outer peripheral surface is inserted into the through hole 30a. A guide shaft 32 is inserted through the other through hole 30b. The screw shaft 31 and the guide shaft 32 are installed on a support member (not shown) in a parallel and horizontal state, and one screw shaft 31 is rotatably supported by the support member. The support member is provided with a drive motor, a reduction gear mechanism, and the like (not shown), and the screw shaft 31 and the motor output shaft of the drive motor are connected via the reduction gear mechanism. For this reason, when the drive motor rotates, the driving force is transmitted to the motor output shaft, the reduction gear mechanism, the screw shaft 31 and the internal thread of the through hole 30a of the holder 30, so that it depends on the rotation direction of the motor output shaft. Thus, the holder 30 can be screwed forward and backward in the Y direction in the figure. That is, the pair of screw shafts 31 and guide shafts 32, the drive motor, the motor output shaft, the reduction gear mechanism, and the like constitute first transfer means for screw-feeding the holder 30 in the Y-axis direction.

  On the other hand, between one leg 30A and the other leg 30B of the holder 30, a pair of screw shafts 41 and guide shafts 42 extending in the X direction shown in the drawing are spaced from each other at a predetermined interval in the Y direction shown in the drawing. The screw shaft 41 and the guide shaft 42 are respectively inserted into through holes (not shown) provided in the movable base 40. In addition, a drive motor, a reduction gear mechanism, and the like (not shown) constituting second transfer means are mounted in the holder 30, and the movable base 40 is screwed in the X-axis direction shown in the drawing according to the rotation direction of the drive motor. It can be done.

  That is, the first transfer means can move the holder 30 on which the movable base 40 is mounted in the Y direction, and the second transfer means can move only the movable base 40 in the X direction. The first transfer means and the second transfer means function as tracking drive means for moving the movable base 40 in the horizontal direction (X and Y directions).

  When the recording medium is a disc-shaped disk and is configured to be held and rotated between the clamper and the turntable (disk drive means), the movable base is simply moved in the radial direction of the disk. Therefore, the tracking drive means can cope with the structure by moving one of the first and second transfer means in the radial direction.

  The movable base 40 is provided with a case 40A having a substantially box shape, and a reproducing unit 50 is provided in the case 40A. The case 40A can be moved in the Z1-Z2 direction by a focus driving means (not shown). The focus driving means can be constituted by, for example, an electromagnetic driving mechanism composed of a magnet and a coil, and an angle deviation adjusting means 60 described later may also serve as the focus driving means.

  As shown in FIGS. 1 to 3, the reproducing unit 50 passes through a laser light source 51, a beam expander 52 that expands the size of laser light (coherent light) generated from the laser light source 51, and the beam expander 52. An optical scanner 53 that changes the direction of the reference light B1 and sends it in an arbitrary direction, a focusing lens 54 that sends incident light to a certain point on the recording medium 1, and reproduction light diffracted by the recording medium 1 The main image sensor (imaging means) 55 that reads the information of B2 and converts it into an electrical signal, and the received light intensity of the data light D (respectively indicated as Da, Db, Dc, Dd) included in the reproduction light B2 are detected. A plurality of light detection means 56 (four in the present embodiment, which are individually indicated as 56 a, 56 b, 56 c, 56 d), and inclinations of the main image sensor 55 and the light detection means 56. Has various members of the optical system, such as angular displacement adjusting means 60 for adjusting. The laser light source 51, the beam expander 52, the optical scanner 53, and the focusing lens 54 constitute light emitting means 50A that irradiates the recording medium 1 with laser light as reference light B1. For example, a galvanometer mirror can be used as the optical scanner 53.

  As the main image sensor 55 and the light detection means 56, a CCD, a CMOS image sensor, or the like can be used. However, as shown in FIG. 3, the number of pixels included in the light detection units 56 a, 56 b, 56 c, and 56 d is smaller than the number of pixels included in the main imaging element 55 and is small. The main image pickup device 55 is fixed to a central portion of a flat pedestal 57, and the four photodetecting means 56a, 56b, 56c, 56d are on the same pedestal 57 and at the four corners outside the main image pickup device 55. It is fixed to. The four light detection means 56a, 56b, 56c and 56d detect data light Da, Db, Dc and Dd output corresponding to adjustment marks Ma, Mb, Mc and Md, which will be described later, of the reproduction light B2, respectively. To do. In addition, as the light detection means 56a to 56d, a split type PD (photodiode) having a plurality of light receiving portions may be used.

  The angle deviation adjusting means 60 is provided on the lower surface of the case 40A, and adjusts the inclination angle of the pedestal 57 to which the main image sensor 55 and the light detecting means 56a, 56b, 56c, 56d are fixed with respect to the case 40A. Is. The angle deviation adjusting means 60 is constituted by, for example, an actuator using a piezoelectric element that causes distortion when a voltage is applied, or an actuator using a magnet and a coil and using electromagnetic force.

  The recording medium reproducing apparatus A is provided with control means (not shown) for controlling operations of the tracking drive means, focus drive means control means, reproduction mechanism means 20, and angular deviation adjustment means 60, and the like. .

  On the recording medium 1, for example, interference fringes generated by reference light as shown in FIG. 4 and object light including information to be recorded are recorded as planar two-dimensional image data information (hologram information) M. Yes. During recording, a large number of two-dimensional image data information M is superimposed in the same recording area on the recording medium by changing the incident angle or wavelength of the reference light for each object light (each information to be recorded). Has been recorded.

  Here, the two-dimensional image data information (hologram information) M shown in FIG. 4 includes a code M0 formed in a certain area, and black circle-shaped adjustment marks Ma provided at four corners outside the area. It has Mb, Mc and Md. The code M0 is planar image data in which white points and black points indicating signals “1” and “0” are arranged in a matrix. The adjustment marks Ma, Mb, Mc and Md are for setting the relative positional relationship between the reproducing unit 50 and the recording medium 1 with high accuracy.

Note that the distance between a group of parallel lattice planes (interference fringes) in the spatial lattice of the crystal of the recording medium 1 is d, and when the reflected wave by this lattice plane group is considered, the viewing angle (cosine of the incident angle φ) ) Is θ (= π / 2−φ), the wavelength of the reference light B1 is λ, and n is a positive integer, the Bragg conditional expression 2dsinθ = nλ is satisfied. It becomes phase and strengthens, and diffraction appears in that direction. Therefore, assuming that the values of n and d are constant, not only the method of changing the direct viewing angle θ of the reference light but also the wavelength λ is changed from the relationship of θ = sin ⁻¹ (nλ / 2d). As a result, information to be recorded by changing the interval d between the lattice planes (interference fringes) formed in the recording medium 1 is recorded in the same recording area on the recording medium 1 in a multiplexed manner.

  Further, when reading information recorded by wavelength multiplexing in this way, even if light having a wavelength different from the desired wavelength is incident, the desired angle can be adjusted by adjusting the incident angle θ to satisfy the black conditional expression. It is possible to read the information.

  Next, a method for reading information (two-dimensional image data information M) recorded on the recording medium 1 using the recording medium reproducing apparatus A will be described. In the following, one recording area in the recording medium 1 is referred to as a book (book), and one interference fringe recorded in a plane in the book for each angle is referred to as a page (page). explain.

  The laser light emitted from the laser light source 51 passes through the beam expander 52 and enters the optical scanner 53 as the reference light B1. Then, by adjusting the optical scanner 53, the reference light B1 incident on the optical scanner 53 is reflected or refracted at a specific angle. The reference light B1 refracted at this specific angle is incident on the recording medium 1 by the focusing lens 54.

  For example, when reproducing the information recorded on the nth page, the reference beam B1 is incident on the recording medium 1 at the same incident angle φ (n) as that recorded on the nth page. The reference light B1 (n) incident on the recording medium 1 is diffracted in the recording medium 1 by the hologram principle, and at this time, the light is diffracted by the corresponding interference fringes, and the light is used as the reproducing light B2 (n). And enters the main imaging means 55. Then, the main imaging means 55 converts the optical information obtained from the reproduction light B2 (n) into an electrical signal, whereby the hologram information recorded on the nth page of the recording medium 1 is converted into the two-dimensional image data information M. Can be read out.

  For example, when information recorded on the (n + 1) th page is reproduced, the optical scanner 53 is adjusted to generate reference light B1 (n + 1) having an incident angle of φ (n + 1) and the recording. When incident on the medium 1, the reproduction light B 2 (n + 1) corresponding to the interference fringes recorded on the (n + 1) th page is emitted from the recording medium 1. Therefore, the information recorded on the (n + 1) th page of the recording medium 1 is converted into the two-dimensional image data information by converting the optical information obtained from the reproduction light B2 (n + 1) by the main imaging means 55 into an electrical signal. It can be read as M.

  Similarly, when reproducing other information, by adjusting the optical scanner 53 and appropriately changing the incident angle φ of the reference light B1 incident on the recording medium 1, different angles are applied to the recording medium 1. It is possible to reproduce other information recorded in

  As described above, a large number of interference fringes are recorded on the recording medium 1 as two-dimensional two-dimensional image data information M for each page in each book. In order to reproduce such interference fringes recorded in the recording medium 1 as the two-dimensional image data information M without error, it is necessary to improve the SN ratio during reproduction. Therefore, at the time of reproduction, the relative position relationship between the reproducing unit 50 and the recording medium 1 is set with high accuracy by making full use of the tracking drive unit and the focus drive unit.

  However, when one of the reproducing unit 50 or the recording medium 1 is tilted, the relative positional relationship between the reproducing unit 50 and the recording medium 1 can be set with high accuracy only by the tracking driving unit and the focus driving unit. Difficult to do.

  Therefore, the angle adjustment using the angle deviation adjusting means 60 is necessary. First, the flow of the angle deviation adjusting method will be described with reference to FIG. FIG. 5 is a flowchart showing a rough flow of the angle deviation adjusting method, and ST in the flowchart indicates a step (STEP) number.

  As shown in FIG. 5, the control means confirms whether or not the card-like recording medium 1 is loaded in the holding means 10. When the control unit confirms that the recording medium 1 is loaded in the holding unit 10, the control unit turns on the laser light source 51. The reference light B1 emitted from the laser light source 51 is reflected by the galvanometer mirror of the optical scanner 53 set to an arbitrary initial angle and set to a state in which the recording medium 1 is irradiated (initial setting).

  The control means roughly drives the tracking drive means as ST1 to move the movable base 40 to the initial position on the recording medium 1 in the horizontal direction. At this time, the main image pickup device 55 has acquired the reproduction light B2 output from the recording medium 1, and the control means stops the movable base 40 at a position where the amount of received light of the reproduction light B2 becomes maximum ( Tracking coarse adjustment).

  In ST2, the tracking driving means is further finely driven. At this time, the control means is one of the four light detection means 56a, 56b, 56c and 56d, and the data light Da, Db, Dc, which is output corresponding to the adjustment marks Ma, Mb, Mc and Md. The movable base 40 is moved to a position where at least one data light of Dd can be received (tracking fine adjustment).

  In ST3, the focus driving means is mainly driven. At this time, the control means adjusts so that all the light detection means 56a, 56b, 56c, and 56d move to positions where they can receive the data light Da, Db, Dc, and Dd, respectively. Adjustment). However, at this time, it is preferable to perform the tracking fine adjustment together so that the data light aligned in the focus fine adjustment in ST2 does not deviate from the light detection means 56.

  Next, as shown in ST4, the control means drives the angle deviation adjusting means 60, and the inclination of the pedestal 57 on which the main image sensor 55 and the four light detecting means 56a, 56b, 56c, 56d are fixed. By finely adjusting the angle, the relative positional relationship between the reproducing unit 50 and the recording medium 1 is set with high accuracy.

  In ST3, all the light detection means 56a, 56b, 56c, and 56d may not receive the data light Da, Db, Dc, and Dd at a time. Therefore, after processing ST3, ST4 → ST1 → ST2 → ST3. By repeating the loop, all the light detection means 56a, 56b, 56c and 56d may receive the data light Da, Db, Dc and Dd.

  Finally, as shown in ST5, the control means reads the code M included in the reproduction light B2 using the main imaging element 55.

Next, the method for adjusting the angle deviation in ST4 will be described in detail.
FIG. 6 is a flowchart showing the first embodiment of the angle deviation adjusting method.

  As shown in FIG. 6, the position of each data beam Da, Db, Dc, Dd on each photodetecting means 56a, 56b, 56c, 56d is detected (ST4-1-1).

  Then, the control means determines whether or not the position of each data beam Da, Db, Dc, Dd is at a predetermined position (center position in the present embodiment) of each light detection means 56a, 56b, 56c, 56d. Perform (ST4-1-2). When the light detection means 56 is an array type formed of an assembly of a large number of light receiving elements such as a CCD or CMOS image sensor, each light detection means 56a, 56b, 56c, 56d is illuminated. It is easy to detect the positions of the data beams Da, Db, Dc, Dd.

  At this time, if the position of each data beam Da, Db, Dc, Dd is deviated from the center position of each light detection means 56a, 56b, 56c, 56d (in the case of No), the control means The driving direction and the driving amount of the angle deviation adjusting means 60 necessary for the data light Da, Db, Dc, Dd to move to the center position of the respective light detecting means 56a, 56b, 56c, 56d are calculated (ST4-1). -3).

  Then, the control means drives the angle deviation adjusting means 60 based on the driving direction and the driving amount so that all the data light approaches the center position of all the light detecting means 56a, 56b, 56c, 56d. (ST4-1-4). After driving, the control of ST4-1-4 to ST4-1-3 is performed again.

  On the other hand, in the determination in ST4-1-2, when it is determined that the position of each data beam Da, Db, Dc, Dd is located at the center of each light detection means 56a, 56b, 56c, 56d (Yes) In the case of (3), the process proceeds to ST5, where the main image pickup device 55 reads the code M0 included in the reproduction light B2.

  In this way, by adjusting the data light Da, Db, Dc, Dd, which are part of the reproduction light, to be moved to the optimum positions, the main image sensor 55 provided in the reproduction unit 50 and the recording are recorded. It becomes possible to match the relative positional relationship with the medium 1 with high accuracy.

  Next, as a second embodiment, an angle deviation adjusting method when the reproduction light is focused light will be described. FIG. 7 is a flowchart showing a second embodiment of the angular deviation adjusting method.

  In the case of hologram reproduction, when reference light having the same incident angle and wavelength as the reference light used for recording is incident on the same recording area of the recording medium 1, it is diffracted by the interference fringes in the recording medium 1. The reproduction light is output as light showing the same contents as the object light at the time of recording. At this time, if the object light at the time of recording is divergent light, the reproduction light at the time of reproduction becomes divergent light, and if the object light is a focused light, the reproduction light at the time of reproduction becomes focused light.

  For this reason, if there is a shift in the relative position between the main image pickup device 55 mounted on the reproducing unit 50 and the recording medium 1, each of the light detection means 56a, 56b, 56c and 56d detected by the four light detection means 56a, 56b, 56c and 56d. The data beams Da, Db, Dc, Dd are output with different spot diameters.

  First, the control unit acquires the light reception patterns of the data lights Da, Db, Dc, and Dd detected by the light detection units 56a, 56b, 56c, and 56d, respectively. At this time, the control means calculates the size (diameter dimension) of the spot diameter of each data light Da, Db, Dc, Dd in each light detection means 56a, 56b, 56c, 56d from the acquired light receiving pattern ( ST4-2-1).

  When the reproduction light B2 is diffused light, the spot diameters differ in the respective light detection means 56a, 56b, 56c, and 56d in accordance with the amount of the relative positional deviation. Therefore, the control means calculates an average value of the spot diameters of the respective data lights, and the spot diameters of the respective data lights Da, Db, Dc, Dd are within a predetermined allowable value based on the average value. It is determined whether or not (ST4-2-2). In addition, since it is difficult to determine when the number of each data beam is small, a predetermined allowable value that is held in advance may be compared with the spot diameter of each data beam.

  In any case, when the size of the detected spot diameter exceeds the predetermined allowable value (in the case of No), the size of each data light Da, Db, Dc, Dd is the predetermined allowable value. A driving direction and a driving amount necessary to be within the value are calculated (ST4-2-3). Then, the control means determines that the spot diameters of all the data light beams Da, Db, Dc, Dd formed on all the light detection means 56a, 56b, 56c, 56d based on the driving direction and the driving amount have a predetermined tolerance. The angular deviation adjusting means 60 is driven so as to be within the value, that is, so that the sizes of the spot diameters coincide with each other (ST4-2-4). After driving, the control in ST4-1-1 to ST4-1-3 is performed again.

  On the other hand, if it is determined in ST4-2-2 that the spot diameter is determined to be within a predetermined allowable value (in the case of Yes), the process proceeds to ST5, and the main image sensor 55 is The code M0 included in the reproduction light B2 is read.

  Next, as a third embodiment, an angle deviation adjusting method in the case where the reproduction light is focused light will be described. FIG. 8 is a flowchart showing a third embodiment of the angular deviation adjusting method.

  When the reproduction light B2 is a focused light, a defocusing (blooming) occurs in which the focal points of the four data light beams Da, Db, Dc, Dd do not coincide with the light receiving surfaces of the respective light detection means 56a, 56b, 56c, 56d. The size of the spot diameter of each data light is different for each light detection means 56a, 56b, 56c, 56d.

  Therefore, the control means obtains the light reception patterns of the data beams Da, Db, Dc, Dd detected by the respective light detection means 56a, 56b, 56c, 56d, as in ST4-2-1. ST4-3-1) From the acquired light receiving pattern, the spot size (diameter size) of each data beam Da, Db, Dc, Dd in each light detection means 56a, 56b, 56c, 56d is calculated. (ST4-3-2). And a control means determines whether the magnitude | size of the spot diameter of each data beam | light Da, Db, Dc, Dd is settled in the range of the predetermined | prescribed appropriate value (ST4-3-3).

  At this time, when the spot diameter exceeds the predetermined range of the appropriate value (in the case of No), the focal points of the four data beams Da, Db, Dc, Dd are different from each other due to the difference in the spot diameters. The drive direction and drive amount of the angle deviation adjusting means 60 necessary for matching the light receiving surfaces of the light detecting means 56a, 56b, 56c, 56d are calculated (ST4-3-4). The control means is configured so that the spot diameters of all the data lights formed in all the light detection means 56a, 56b, 56c, and 56d are minimized based on the driving direction and the driving amount. The angle deviation adjusting means 60 is driven (ST4-3-5). After driving, the control of ST4-3-1 to ST4-3-3 is performed again.

  On the other hand, in the determination in ST4-3-3, when the spot diameter is determined to be within a predetermined appropriate value (in the case of Yes), the process proceeds to ST5, and the main imaging element 55 is transferred. Reads the code M0 included in the reproduction light B2.

  By the angle deviation adjusting method shown in FIGS. 5 to 8, the relative position deviation between the main image sensor 55 and the recording medium 1 can be eliminated or set to the minimum. At this time, since the received light intensity of the reproduction light B2 received by the main imaging element 55 is in a maximum state, the main imaging element 55 uses the two-dimensional image data information of the code M0 included in the reproduction light B2. It is possible to read the data reliably.

  In the above-described embodiment, the configuration in which the light detection means 56a, 56b, 56c, and 56d as dedicated image pickup means provided separately and independently from the main image pickup device 55 as means for detecting data light is shown and described. However, the present invention is not limited to this, and a configuration in which a dedicated area for receiving the data light is allocated in the main image sensor 55 may be used. In this case, since each of the four light detection means 56a, 56b, 56c, and 56d can be made unnecessary, cost reduction and reduction in size and weight can be promoted.

  In the above-described embodiment, the adjustment marks are recorded at four positions on each page and four data lights are acquired based on the adjustment marks. However, the present invention is not limited to this, and the adjustment marks are not limited thereto. The number of may be two or more.

Sectional drawing which shows the outline of the recording-medium reproducing | regenerating apparatus using a hologram as embodiment of invention, The block diagram which shows the reproduction | regeneration mechanism means for recording media mounted in the movable base, A plan view showing the arrangement of the imaging means and the light detection means, The top view which shows an example of the two-dimensional image data information (hologram information) used for embodiment of this invention, A flowchart showing a rough flow of an angle deviation adjustment method; The flowchart which shows 1st Embodiment of an angle shift adjustment method, The flowchart which shows 2nd Embodiment of an angle shift adjustment method, The flowchart which shows 3rd Embodiment of an angle shift adjustment method, Explanatory drawing which shows the principle of operation in the case of performing recording and reproduction using a hologram,

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording medium 10 Holding means 10A Opening part 11 Base 12 Wall surface 13 Upper plate 14 Energizing member 20 Reproducing mechanism means 30 Holder 31 Screw shaft 32 Guide shaft 40 Movable base 51 Laser light source (light emitting means)
52 Beam Expander 53 Optical Scanner (Galvano Mirror)
54 focusing lens 55 main image sensor (imaging means)
56, 56a, 56b, 56c, 56d Light detection means 57 Base 60 Angle deviation adjustment means A Recording medium reproduction device B1 Reference light B2 Reproduction light M Two-dimensional image data information (hologram information)
Ma, Mb, Mc, Md Adjustment mark M0 code

Claims (17)

  Light emitting means for emitting coherent light as reference light, imaging means for acquiring reproduction light generated by diffracting the reference light by interference fringes recorded on a recording medium, and a movable device equipped with the imaging means A base, an angle deviation adjusting means for adjusting an inclination angle of the imaging means, and a control means for controlling the angle deviation adjusting means so that the received light intensity of the reproduction light acquired by the imaging means is maximized. A recording medium reproducing apparatus using a hologram.   The recording medium reproducing apparatus using a hologram according to claim 1, wherein the light emitting means and the imaging means are mounted on the same movable base.   In the recording medium, data information in units of pages is recorded in multiple in a predetermined recording area, and each page is provided with two or more adjustment marks for detecting the received light intensity of the reproduction light, 2. The movable base is provided with light detection means for detecting data light generated due to diffraction of the reference light among the reproduction light by the adjustment mark. Alternatively, a recording medium reproducing apparatus using the hologram described in 2.   4. The apparatus for reproducing a recording medium using a hologram according to claim 3, wherein the light detection means is formed as a dedicated area in the imaging means assigned to each data light.   4. The recording medium reproducing apparatus using a hologram according to claim 3, wherein the light detecting means is provided as a dedicated imaging means different from the imaging means.   6. The hologram according to claim 3, wherein the angle deviation adjusting means is controlled so that two or more data lights move to a predetermined position of the light detecting means corresponding thereto. Recording medium playback device using   6. The angle deviation adjusting means is controlled so that the spot diameters of the two or more data lights detected by the detecting means have a predetermined size, respectively. A recording medium reproducing apparatus using the hologram described above.   6. The angle deviation adjusting means is controlled so that the spot diameters of the two or more data lights detected by the light detecting means are equal to each other. A recording medium reproducing apparatus using the hologram described in 1.   6. The recording medium using the hologram according to claim 3, wherein the angle deviation adjusting unit is controlled so that a spot diameter of the focal point of the data light is minimized. Playback device.   10. The hologram according to claim 1, wherein the angle deviation adjusting means for adjusting the movable base is formed by a piezoelectric actuator using distortion deformation of a piezoelectric element. Recording medium playback device.   The angle deviation adjusting means for adjusting the movable base is formed by an electromagnetic actuator using an electromagnetic force generated between a coil and a magnet. Recording medium reproducing apparatus using the hologram.   The movable base is provided with tracking drive means for moving the movable base in a horizontal direction within a plane parallel to the recording medium, and focusing drive means for moving the movable base in a vertical direction perpendicular to the horizontal direction. A recording medium reproducing apparatus using a hologram according to claim 1, wherein the recording medium reproducing apparatus is a hologram recording apparatus.   The recording medium reproducing apparatus using a hologram according to claim 1, wherein the imaging unit is a CCD or a CMOS image sensor. Light emitting means for emitting coherent light as reference light, imaging means for acquiring reproduction light generated by diffracting the reference light by any of a plurality of interference fringes recorded on a recording medium, and each of the means , An angle deviation adjusting unit that adjusts an inclination angle of the imaging unit, a tracking drive unit that moves the movable base in a horizontal direction in a plane parallel to the recording medium, and the horizontal direction Focusing driving means for moving the movable base in a vertical direction orthogonal to the control means, control means for driving and controlling the respective means, and each reproduction of each page of the recording medium on which the page-unit data information is recorded in a multiplexed manner Two or more adjustment marks for detecting the light reception intensity of light are provided, and a plurality of data generated due to the adjustment marks of the reproduction light are generated. And a light detection means for receiving a data light,
(1) a coarse tracking adjustment step of moving the movable base to a position where the amount of light received by the imaging means is maximized;
(2) a tracking fine adjustment step in which the light detection means moves the movable base to a position where at least one of the plurality of data lights can be received;
(3) a focus fine adjustment step of moving at least the imaging unit to a position where the light detection unit can receive all the data light, respectively;
(4) a tilt angle fine adjustment step of driving the angle deviation adjusting means so that each data light spot moves to a predetermined position of the light detecting means corresponding thereto;
A method of adjusting an angular deviation of a recording medium reproducing apparatus using a hologram, comprising:   The step (4) has a tilt angle fine adjustment step of driving the angle deviation adjusting means so that the spot diameters of two or more data lights have predetermined sizes, respectively. 14. A method for adjusting an angle deviation of a recording medium reproducing apparatus using the hologram according to 14.   The step (4) includes a tilt angle fine adjustment step of driving the angle deviation adjusting means so that the spot diameters of two or more data beams coincide with each other. 14. A method for adjusting an angle deviation of a recording medium reproducing apparatus using the hologram according to 14.   The step (4) includes a tilt angle fine adjustment step of driving the angle deviation adjusting means so that the spot diameters of the data light at all locations are minimized. 14. A method for adjusting an angle deviation of a recording medium reproducing apparatus using the hologram according to 14.

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