KR100727779B1 - Optical information reproducing apparatus, optical information recoding/reproducing apparatus and method for reproducing of optical information by using the same - Google Patents

Abstract

An optical information reproducing apparatus, an optical information recording and reproducing apparatus, and an optical information reproducing method using the same are provided to sense a tilt error by using a reference beam and a pair of auxiliary beams when optical information is reproduced and correct the tilt error when the tilt error is generated. A beam splitter(120) splits a beam emitted from a light source(110) into a reference beam and a temporal beam. An auxiliary beam splitter(130) splits the temporal beam and generates a pair of auxiliary beams. An incident optical system having an overlap optical system(140) and a focus optical system(160) inputs the reference beam and the auxiliary beams to a storing medium which stores optical information. A reproduction beam reader(174) reads a reproduction beam reproduced by the reference beam, and sets a signal area by using a reproduction beam for emitting the maximum light quantity among the reproduction beams as a reference position. An auxiliary beam reader(176) compares the light strength of a pair of the auxiliary beams inputted to the signal area, and sets an incident angle of the reference beam.

Description

Optical information reproducing apparatus, optical information recording and reproducing apparatus, and optical information reproducing apparatus using the same {Optical information reproducing apparatus, optical information recoding / reproducing apparatus and method for reproducing of optical information by using the same}

1 is a block diagram showing an optical information reproducing apparatus according to the present invention.

2A is a block diagram showing an optical information recording and reproducing apparatus according to the present invention, and is a simplified diagram showing an optical path when recording optical information.

2B is a block diagram showing an optical information recording and reproducing apparatus according to the present invention, which is a simplified diagram showing an optical path when optical information is reproduced.

3 is a flowchart illustrating a method of reproducing optical information according to the present invention.

4A to 4B are simplified diagrams showing an optical intensity-angle selectivity curve for correcting a tilt error in the optical information reproducing method according to the present invention.

5A to 5B are exemplary views illustrating detection of auxiliary light in the optical information reproducing method according to the present invention.

** Description of the symbols for the main parts of the drawings **

100: optical information reproducing apparatus

110: light source

120: polarized light splitter

130: auxiliary light separator

140: superposition optical system

160: focus optical system

170: reading unit

The present invention relates to an optical information reproducing apparatus, and more particularly, an optical information reproducing apparatus for detecting a tilt error by using a reference light and a pair of auxiliary lights and correcting a tilt error when optical information is reproduced. An information recording and reproducing apparatus and an optical information reproducing method using the same.

Optical data processing apparatuses include Digital Versatile Disc (DVD), HD-DVD, Blu-ray Disc (BD), near field light processing apparatus, holographic light processing apparatus, and the like.

The holographic light processing apparatus irradiates an optical information storage medium with a signal beam that is optically modulated and a reference beam that intersects the signal light to form an interference pattern on the optical information storage medium. Save it.

In the reproduction of data, only the reference light is irradiated to the optical information storage medium, the reproduced light reproduced in the optical information storage medium is detected by a detector, and the detected information is processed to obtain input data.

In addition, the optical information processing apparatus using the hologram may store the data at the same position of the optical information recording medium by using various multiplexing techniques. As a result, even if the optical information recording medium having the same area can be dramatically increased storage capacity. Known multiplexing techniques include angle multiplexing, phase-code multiplexing, wavelength multiplexing, fractal multiplexing, shift multiplexing, peristrophic multiplexing ).

Meanwhile, the optical information may not be stored in only one place of the optical information storage medium. That is, various information is stored in different locations of the optical information storage medium. Therefore, in order to reproduce the optical information input to the optical information storage medium, the optical information storage medium has to be moved to the optical information reproducing position. For example, in the case of a disc-shaped optical information storage medium, optical information is reproduced while rotating the disc.

A prior art for moving optical information storage media is U.S. Patent No. 5,978,112, entitled "NON-VOLATILE READOUT OF SHIFT MULTIPLEXED HOLOGRAMS," filed by Psaltis et al.

The patent discloses a structure and method for tilting an optical information storage medium. That is, when storing the optical information, the optical information storage medium is moved by using the shift servo according to the storage position of the optical information on the optical information storage medium.

As described in the above patent, the optical information storage medium whose position is continuously changed for the reproduction of the optical information is essentially accompanied by mechanical operation such as rotational or linear motion. Accordingly, the tilt state of the reference light and the storage medium may change continuously.

Furthermore, in the case of the volume hologram as described above, the reproduction efficiency of the reproduction light is improved only when the reference light is incident on the volume holographic region having sharp angular selectivity.

That is, when the incident angle of the reference light incident on the storage medium storing the optical information is incident within the Bragg angular, the reproduction efficiency of the reproduced light reproduced by the reference light increases.

Therefore, the angle of incidence of the reference light is determined according to the tilt state of the storage medium. The diffraction efficiency of the reference light incident on the storage medium largely depends on the angle of incidence of the reference light (ie, the tilt state of the storage medium).

 Therefore, when the incident angle of the reference light, which changes according to the tilt state of the storage medium, is out of the Bragg angle, there is a problem that the regeneration efficiency of the reproduced light is significantly lowered.

Accordingly, it is necessary to detect and correct whether a tilt error occurs between the reference light and the storage medium when recording data to or reproducing the data of the storage medium.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an optical information reproducing apparatus capable of correcting a tilt error by injecting an auxiliary light into a storage medium when optical information is reproduced.

Another object of the present invention is to provide an optical information recording and reproducing apparatus capable of correcting an optical information tilt error by injecting auxiliary light into a storage medium when optical information is reproduced.

Another object of the present invention is to provide an optical information reproducing method capable of correcting an optical information tilt error by injecting auxiliary light into a storage medium when optical information is reproduced.

An optical information reproducing apparatus according to the present invention for achieving the above object, the light source; A light splitter separating the light emitted from the light source into reference light and temporary light; An auxiliary light separator for separating the temporary light to form a pair of auxiliary lights; An incident optical system for incident the reference light and the auxiliary light onto a storage medium storing optical information; A reproduction light reader which reads out the reproduction light reproduced by the reference light and sets the signal area with the reproduction light emitting the maximum amount of light out of the reproduction light as a reference position; And an auxiliary light reader configured to set the incident angle of the reference light by comparing the light intensities of the pair of auxiliary lights incident to the signal region.

The auxiliary light is preferably inclined at a corresponding angle at different positions with respect to the reference light to be incident on the storage medium.

The optical information recorded on the storage medium is a holographic interference fringe, and the auxiliary light is incident to a position where the reference light is incident and diffracted together with the reference light.

Preferably, the reference light and the auxiliary light are incident to the same point of the storage medium, and a read light splitter is further provided to separate the reproduced light reproduced from the storage medium and the auxiliary light transmitted through the storage medium.

The auxiliary light reader preferably includes a plurality of photodiodes arranged in a tilting direction in which the reference light is controlled.

The length of the photodiode is preferably greater than the sum of the distance between the incident points of the auxiliary lights and the moving distance of the incident points in the tilting control of the reference light.

An optical information recording and reproducing apparatus according to the present invention for achieving the above object comprises a light source;

A non-polarization light splitter that separates light emitted from the light source; A signal light optical system for loading data into one light separated by the non-polarization light splitter to form a signal light and to enter the storage medium; A polarized light splitter that separates the remaining light separated by the non-polarized light splitter into a reference light and a temporary light; An auxiliary light separator configured to diffuse and separate the separated temporary light at an angle symmetrical with respect to an optical axis of the temporary light to form a plurality of auxiliary lights; An incident optical system for incident the reference light and the auxiliary light onto a storage medium storing optical information; A reproduction light reader which reads out the reproduction light reproduced by the reference light and sets the signal area with the reproduction light emitting the maximum amount of light out of the reproduction light as a reference position; And an auxiliary light reader configured to set the incident angle of the reference light by comparing the light intensities of the pair of auxiliary lights incident to the signal region.

The auxiliary light is preferably inclined at a corresponding angle at different positions with respect to the reference light to be incident on the storage medium.

The optical information recorded on the storage medium is a holographic interference fringe, and the auxiliary light is incident to a position where the reference light is incident and diffracted together with the reference light.

Preferably, the reference light and the auxiliary light are incident to the same point of the storage medium, and a read light splitter is further provided to separate the reproduced light reproduced from the storage medium and the auxiliary light transmitted through the storage medium.

And the auxiliary light reader includes a plurality of photodiodes arranged in a tilting direction in which the reference light is controlled.

The length of the photodiode is arranged is greater than the sum of the distance between the incident point of the auxiliary light and the moving distance of the incident point in the tilting control of the reference light.

According to an aspect of the present invention, there is provided a method of reproducing optical information, the method comprising: incident a reference light onto a storage medium storing multiplexed optical information; Tilting the reference light to scan the multiplexed optical information; Finding a reference position emitting the maximum amount of light by the reference light in the scanned light information; Setting a signal area based on the reference position; Injecting a pair of auxiliary light into the signal region at the same position as the reference light; Measuring an amount of light of each auxiliary light; And comparing the amount of light of the respective auxiliary lights with each other to set an incident angle of the reference light.

The auxiliary lights are preferably inclined at corresponding angles at different positions to be incident on one point of the storage medium.

The measurement of the auxiliary light is preferably performed by a plurality of photodiodes extending to the moving region of the auxiliary light.

The photodiodes are divided into a plurality of sensing units, and the light intensity of the auxiliary light measured in the sensing unit is calculated by adding to the photodiodes forming the sensing unit.

Preferably, the slope of the storage medium is read by comparing the sensing unit having the largest sensing value and the sensing unit having the second largest sensing value among the sensing units.

The setting of the incident angle of the reference light is preferably set in a direction in which the difference in the amount of light of the respective auxiliary lights decreases.

Hereinafter, an optical information reproducing apparatus, an optical information recording and reproducing apparatus, and an optical information reproducing method using the same will be described in detail with reference to the accompanying drawings.

In the description of the present invention, the names of the elements defined are defined in consideration of functions in the present invention, and should not be understood as meanings that limit the technical elements of the present invention. May be referred to by other names in the art. In addition, the code added to each component is described for convenience of description, and the contents shown in the drawings in which these codes are described do not limit each component to the range in the drawing. In addition, as long as the functional similarity and identity thereof, even if the modified embodiment is adopted, it can be seen as an equivalent configuration, and even if the embodiment in which the modified part of the configuration is employed, it can be seen as an equivalent configuration.

First, the optical information reproducing apparatus according to the present invention will be described with reference to FIG. 1 is a block diagram showing an optical information reproducing apparatus according to the present invention.

As shown, the optical information reproducing apparatus 100 according to the embodiment of the present invention includes a light source 110, a polarized light splitter 120, an auxiliary light separator 130, an overlapping optical system 140, and a focus. The optical system 160 and the reading unit 170 are provided.

The light source 110 generates light L having a predetermined wavelength, and the light L generated by the light source 110 is a parallel light beam, which is a plane wave-type laser light having excellent coherent. It is preferred, for example, to have the wavelength required for holographic data storage.

The polarized light splitter 120 may convert the light L generated by the light source 110 into reference light R for reproducing optical information and temporary light A for generating first and second auxiliary lights A1 and A2. ), Which has a polarization splitting surface 120a for polarizing splitting incident light L in a structure in which two or more kinds of materials having different refractive indices are repeatedly deposited, and the polarization splitting surface 120a is temporary. The light (P polarization) A transmits and the reference light (S polarization) S reflects.

In addition, a separate light source adjusting member 124 may be provided to adjust the reference light R and the first and second auxiliary lights A1 and A2 separated from the polarized light splitter 120. The light source adjusting member 124 may be provided as a polarizing plate, a photosensitive filter, and the like. The light source adjusting member 124 may precisely adjust the intensity and uniformity of the reference light R and the first and second auxiliary lights A1 and A2. It is installed if necessary, and may not be installed if the characteristics of the reference light (R) and the temporary light (A) is guaranteed.

In addition, the aforementioned polarized light splitter 120 may also be provided as a non-polarizer beam splitter (not shown). In this case, the light source adjusting member 124 may be provided as an S polarizing plate and a P polarizing plate for polarizing the reference light R and the temporary light A divided by the non-polarization light splitter into S-polarized light and P-polarized light, respectively. Since various implementations can be changed, detailed description thereof will be omitted.

The auxiliary light splitter 130 is to separate the temporary light A separated by the polarized light splitter 120 into first and second auxiliary lights A1 and A2 for sensing by the reading unit 170 to be described later. The light A may be provided in a path through which the light A passes, and may be provided as a prism spectrometer or a hologram spectrometer for separating incident light A into first and second auxiliary lights A1 and A2.

On the other hand, the reference light (R) separated from the polarized light splitter 120 is incident to the overlapping optical system 140 to be described later by a plurality of reflecting mirrors (126). In this case, the plurality of reflection mirrors 126 are preferably galvano mirrors for adjusting the optical path of the reference light.

The superposition optical system 140 superimposes the first and second auxiliary lights A1 and A2 and the reference light R on a parallel optical axis, and the first and second auxiliary lights A1 and A2 and the reference light R. And a refraction mirror 150 that refracts the reference light R and the first and second auxiliary lights A1 and A2 superimposed by the optical overlapper 142 with a focusing optical system to be described later. And a plurality of focusing lenses 146 provided at the front and rear ends of the optical overlapper 142.

Here, the optical overlapper 142 reflects the reference light R incident at the same time as passing through the first and second auxiliary lights A1 and A2 that are incident on the structure of repeatedly depositing two or more kinds of materials having different refractive indices. An overlapping surface 142a is formed.

Meanwhile, as described above, the reference light R superimposed by the optical overlapper 142 and the first and second auxiliary lights A1 and A2 are incident on the focus optical system 160 by the refraction mirror 150 rotatably provided. . The refractive mirror 150 is preferably a galvano mirror for adjusting the optical paths of the superimposed reference light R and the first and second auxiliary lights A1 and A2.

The focus optical system 160 allows the reference light R reflected by the refraction mirror 150 and the first and second auxiliary lights A1 and A2 to enter the storage medium D. It is provided. On the other hand, it is preferable that the lengths of the optical paths of the first and second auxiliary lights A1 and A2 passing through the focusing optical system have the same length as possible. The intensities of the first and second auxiliary light beams A1 and A2 incident on the storage medium D should be as much as possible or within the error range.

The reading unit 170 reads the incident reference light R passing through the storage medium D and the first and second auxiliary lights A1 and A2. The reference light R incident to the storage medium D is read. The read light splitter 172 separating the regenerated light formed by the first and second auxiliary lights A1 and A2 passing through the storage medium D, and the regenerated light separated by the read light splitter 172. And a secondary light reader 176 for reading the first and second auxiliary lights A1 and A2 separated by the read light splitter 172.

Here, the read light splitter 172 separates the first and second auxiliary lights A1 and A2 passing through the storage medium D and the reproduction light reproduced while the reference light R passes through the storage medium D. The first and second auxiliary lights A1 and A2 pass through the auxiliary light reader 176, and the reference light R is reflected to reproduce the light by repeatedly depositing two or more kinds of materials having different refractive indices. And enters the reader 174.

The reproduction light reader 174 is used to detect the reproduction light reproduced by the reference light R in the optical information storage medium D, and includes a charge-coupled device (CCD) and a complementary metal-oxide semiconductor (CMOS). An image sensing device having the same pixel array may be adopted.

In addition, the auxiliary light reader 176 detects the intensity and position of the first and second auxiliary lights A1 and A2 diffracted together with the reference light R when the optical information is reproduced by the reference light, and in the auxiliary light reader 176 The tilt error of the reference light D and the storage medium D is determined according to the detected result, and arranged to correspond to the moving areas of the first and second auxiliary lights A1 and A2 passing through the storage medium D. A plurality of photodiodes P1... Pn are used (see FIGS. 5A-5B).

The arrangement of the photodiodes P1... Pn is based on a distance d between at least the incident points of the first and second auxiliary lights A1 and A2 and the moving distance of the first and second auxiliary lights A1 and A2 during tilting. It must be longer than the combined length. In addition, at least several to several tens of photodiodes P1... Pn may be provided in combination.

Meanwhile, in another embodiment, the auxiliary light reader 176 may employ a CCD having a low density pixel combination in addition to the photodiodes P1... Pn. If the CCD is adopted, it is possible to output the detected light intensity as an analog value without using a separate analog / digital converter. The auxiliary light reader 176 may also employ a CMOS having a low density pixel combination. In this case, the intensity of light may be determined by the number of pixels in which light is detected. Any of them may be adopted in a form suitable for implementation.

The intensity and position of the first and second auxiliary lights A1 and A2 detected by the auxiliary light reader 176 may be determined by the reference light R and the storage medium D through which the first and second auxiliary lights A1 and A2 pass. Used to determine the tilt error. A more detailed description for reading the tilt error will be described later in detail with the tilt error correction method.

On the other hand, the above-described storage medium (D) may store the holographic optical information by angular multiplexing or may be stored by the above-described recording and reproducing apparatus. In addition, the storage medium (D) may be a kind of photopolymers (photopolymers). Such a storage medium (D) may be, for example, the product name "HRR-660" manufactured by Dupont or the product name "ULSH-500" manufactured by Aprilis, or polymethylmethacrylate (PMMA). have. And other kinds of photopolymer may be adopted, and may be formed in the form of a disk.

Thus, the optical information reproduction of the optical information reproducing apparatus according to the present invention will be briefly described.

First, the light L is emitted from the light source 110 to reproduce the optical information. The light L emitted therefrom is separated into the reference light R and the temporary light A by the polarized light splitter 120, and the separated reference light R and the temporary light A are the light source adjusting member 124. The characteristic (for example, intensity | strength, uniformity, polarization, etc.) is adjusted by this. Then, the adjusted temporary light A is separated into first and second auxiliary lights A1 and A2 by the auxiliary light separator 130.

Meanwhile, the first and second auxiliary lights A1 and A2 separated as described above are incident to the overlapping optical system 140 to overlap with the reference light R. The first and second auxiliary light beams A1 and A2 incident on the superposition optical system 140 overlap the optical axis parallel to the reference light beam R and proceed toward the refractive mirror 150, and the reference light beam R is provided by the refractive mirror 150. And first and second auxiliary lights A1 and A2 superimposed on the reference light R are incident on the storage medium D.

Here, the reference light R incident on the storage medium D is diffracted by the interference fringe formed on the storage medium D, and the reproduced light is formed, and the reproduced light is read by the reproduced light reader 174.

Meanwhile, the first and second auxiliary lights A1 and A2 are incident at the same position of the storage medium D to which the reference light R is incident. In this case, the reference light R may be incident together with the first and second auxiliary lights A1 and A2, and only the first and second auxiliary lights A1 and A2 may be incident. In addition, the incident first and second auxiliary lights A1 and A2 should have the same intensity of light at the time of incidence or within the error range.

Thereafter, the first and second auxiliary lights A1 and A2 incident on the storage medium D pass through the storage medium D and are detected by the auxiliary light reader 176. At this time, the auxiliary light reader detects the intensity and position of the detected first and second auxiliary lights A1 and A2. At this time, the intensity and position information of the first and second auxiliary lights A1 and A2 sensed by the auxiliary light reader 176 are used as data for reading the tilt error.

Hereinafter, the optical information recording and reproducing apparatus according to the present invention will be described with reference to FIGS. 2A to 2B.

FIG. 2A is a schematic diagram showing an optical information recording and reproducing apparatus according to the present invention. FIG. 2A is a schematic diagram showing an optical path when recording optical information. FIG. 2B is a schematic diagram showing an optical information recording and reproducing apparatus according to the present invention. This is a simplified diagram showing the optical path during reproduction.

The optical information recording and reproducing apparatus 200 to be described below is an optical system for generating the signal light S for recording optical information in the optical information reproducing apparatus 100 described above. Therefore, the detailed description of the same configuration as that of the optical information reproducing apparatus 100 will be omitted.

2A to 2B, the optical information recording and reproducing apparatus 200 according to the present invention includes a light source 210, a non-polarization light splitter 220a, a polarization light splitter 220b, and an auxiliary light separator ( 230, an overlapping optical system 240, a refractive mirror 250, a focusing optical system 260, and a reading unit 270.

Here, the light source 210, the polarized light splitter 220b, the auxiliary light splitter 230, the superposition optical system 240, the refractive mirror 250, the focus optical system 260, and the readout unit 270 are described above. Detailed description of the same structure as that of one optical information reproducing apparatus is omitted.

The non-polarization light splitter 220a separates the light L emitted from the light source 210 to form the signal light S and the reference light R. The separated light is a light source control member 222a. Polarized light is formed into the signal light S, and the remaining light is incident on the polarization splitter 220b to be separated into the reference light R and the temporary light A.

On the other hand, in the non-polarization light splitter 220a, one of the lights is polarized into P-polarized light by the light source control member 222a and is formed as the signal light S. In addition, on the optical path of the signal light (S), a separate shutter 224a for blocking the optical path of the signal light (S) at the time of reproducing the storage medium (D), and a spatial light modulator for loading data into the signal light (S) 228 and a Fourier transform lens 229 for injecting the signal light S loaded with data into the storage medium D.

Here, the spatial light modulator 228 is a typical TFT LC (thin film transistor liquid crystal) of the active matrix, super twisted nematic liquid crystal (STN LC) of the passive matrix, ferroelectric liquid crystal (LC), polymer dispersion (PDLC; Polymer) Dispersed Liquid Crystal, and plasma address liquid crystal (PALC) may be employed.

Hereinafter, recording and reproduction of optical information in the optical information recording and reproducing apparatus according to the present invention will be described.

First, when the light information is recorded, as the light L is emitted from the light source 210, the unpolarized light splitter 220a is separated into a pair of light for generating the signal light S and the reference light R. The light is polarized into P polarized light by the light source adjusting member 222a and is converted into the signal light S.

The converted signal light S passes through the spatial light modulator 228 and data is loaded by the spatial light modulator. The signal light S loaded with data enters the storage medium D by the Fourier lens 229. do.

At the same time, the other light separated from the non-polarization light splitter 220a is incident to the polarization light splitter 220b and separated into the reference light R and the temporary light A. At this time, since the temporary light A to be separated is unnecessary at the time of recording optical information, the temporary light A is blocked by the shutter 224b, and its progress is limited.

Meanwhile, the reference light R separated by the polarized light splitter 220b is incident to the superposition optical system 240 by the plurality of reflection mirrors 226, and the reference light R incident to the superposition optical system 240 is the refractive mirror ( The path is switched by 250 and is incident on the storage medium D by the focusing optical system 260.

Accordingly, the holographic interference fringe is formed on the storage medium D by the signal light S and the reference light R incident to the storage medium D. This holographic interference fringe is data for reproducing the storage medium (D).

On the other hand, as the light L is emitted from the light source 210, the light information is separated into a pair of light for generating the signal light S and the reference light R in the non-polarization light splitter 220a. However, one light for generating the signal light S is blocked by the shutter 224a, and its progress is limited.

Thereafter, the other light separated by the non-polarization light splitter is incident to the polarization light splitter 220b and separated into the reference light R and the temporary light A. In this case, the separated reference light R is incident to the overlapping optical system 240 by the plurality of reflection mirrors 226 and overlaps the first and second auxiliary lights A1 and A2 which will be described later.

Meanwhile, the temporary light A separated by the polarized light splitter 220b is separated into the first and second auxiliary lights A1 and A2 by the auxiliary light splitting optical system 230, and the separated first and second auxiliary lights A1 and A2. ) Is incident on the superposition optical system 240 and overlaps with the reference light R so that the path is switched by the refractive mirror 250.

Accordingly, the reference light R and the first and second auxiliary lights A1 and A2 whose paths are switched by the refraction mirror 250 are incident on the storage medium D by the focusing optical system 260, and then enter the storage medium D. The incident reference light R is converted into reproduction light by an interference fringe formed on the storage medium D, and the converted reproduction light and the first and second auxiliary lights A1 and A2 passing through the storage medium D are read out. The light is incident on the optical system 270.

Thereafter, the regenerated light incident on the read optical system 270 and the first and second auxiliary lights A1 and A2 are separated by the read light separator 272 so that the regenerated light is read by the read light reader 274. The first and second auxiliary lights A1 and A2 are read by the auxiliary light reader 276.

In this case, the intensity and position information of the first and second auxiliary lights A1 and A2 sensed by the auxiliary light reader 276 is used as data for reading the tilt error.

Hereinafter, the tilt error of the storage medium by the optical information reproducing apparatus and the optical information recording and reproducing apparatus according to the present invention as described above will be described. Each component to be described below refers to the configuration and code of the above-described optical information reproducing apparatus. However, the configuration of the optical information recording and reproducing apparatus can be referred to. It is also possible to implement these modified embodiments.

Hereinafter, an optical information reproducing method according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a flowchart illustrating a method of reproducing optical information according to the present invention.

As shown, in the optical information reproducing method according to the present invention, first, the reference light (R) is incident on the optical information storage medium (D) (step S110). Here, the first auxiliary light A1 and the second auxiliary light A2 may be incident together as the reference light R incident to the storage medium D.

At this time, the holographic interference fringe is formed in the storage medium D by angular multiplexing so that light diffraction occurs, and the first auxiliary light A1 and the second auxiliary light A2 are located at the same position on the storage medium D. The first and second auxiliary lights A1 and A2 should be identical to each other or within the error range.

Thereafter, the reference light R incident on the storage medium D and the first and second auxiliary lights A1 and A2 are tilted to scan the optical information stored by angle multiplexing at the position where the reference light R is incident (step S120). ).

 In this case, the light intensity-angle selectivity curve of the scanned optical information may be represented as shown in FIGS. 4A to 4B. 4A to 4B are simplified diagrams showing an optical intensity-angle selectivity curve for correcting a tilt error of a storage medium in the optical information reproducing method according to the present invention.

4A is a light intensity-angle selectivity curve when the optical information stored in the storage medium is not multiplexed, and FIG. 4B is a light intensity-angle selectivity curve when the optical information stored in the storage medium is angularly multiplexed.

In addition, it is assumed that the reference light (R) and the first and second auxiliary light incident on the storage medium (D) have the same intensity, and "θ" is the first, second auxiliary light (A1, A2) to the storage medium (D). The incident angle is displayed.

If the intensities of the light of the first auxiliary light A1 and the second auxiliary light A2 incident at the same angle as shown in FIG. 4A are located at the same position on both slopes of the peak curve, the slope of the storage medium D is stored. The diffraction efficiency of the reference light R incident to the medium D is greatest so that the incident angle of the reference light R formed by the inclination of the storage medium D is located at “Bragg angular”.

On the other hand, when the light amount of the first auxiliary light A1 and the second auxiliary light A2 incident at the same angle is positioned in a state having a predetermined difference t, the reference light formed by the inclination of the storage medium D ( Since the incident angle of R) is not located at "Bragg angular", it means that the diffraction efficiency of the reference light R is lowered.

Subsequently, as the optical information of the storage medium D is scanned, a reference position of the reproduction light that emits the maximum amount of the reproduction light measured by measuring the amount of reproduction light generated by diffraction by the optical information of the storage medium D is measured. Rmax) (step S130). In this case, the reference position of the reproduction light may be measured by the reproduction light reader 176, and may be provided with a separate reader (not shown) for finding the reference position Rmax.

After finding the reference position Rmax of the reproduction light emitting the maximum amount of the reproduction light reproduced by the reference light R, the signal region l of the other reproduction lights is defined based on the reference position Rmax ( Step S140).

Here, the signal region l may be determined by a constant value k which is preset based on the reference position. Here, the constant value k is a value between 0 and 1, and the position of the reproduction light located in the signal region l is always formed at a position lower than the reference position Rmax.

This process may be performed when the storage medium D is first read or when the storage medium D is separated from the signal region L due to an external shock or the like during the reproduction of the optical information stored in the storage medium D.

 In this case, when the reference position Rmax is measured as described above, the first and second auxiliary light reference positions A1max and A2max of the maximum amount of light of the first and second auxiliary lights A1 and A2 corresponding to the reference position may be measured. . Here, the first and second auxiliary lights A1 and A2 are detected by a plurality of photodiodes P1... Pn provided in the auxiliary light reader 176, and the first and second auxiliary lights A1 by the auxiliary light reader 176. The reading of A2) will be described separately with reference to Figs. 5A to 5B.

 The first and second auxiliary light reference positions A1max and A2max may be used as defining elements, such as the reference position Rmax, when defining the signal region l. That is, the signal region l may be limited to an area satisfying R > k Rmax, A1 > k A1max, and A2 > A2 Rmax.

After that, when the signal region L is defined by the above-described process, the first and second auxiliary lights A1 and A2 are incident as the reference light R incident to the signal region L of the optical information (step S150). ). Here, the first and second auxiliary lights A1 and A2 may be incident together when the first reference light R is incident.

The amount of light of each of the first and second auxiliary lights A1 and A2 incident thereto is read by the auxiliary light reader 176 (step S160). Here, the first and second auxiliary lights A1 and A2 are detected by a plurality of photodiodes P1... Pn provided in the auxiliary light reader 176, and the first and second auxiliary lights A1 by the auxiliary light reader 176. The reading of A2) will be described separately with reference to Figs. 5A to 5B.

 The incident angle of the reference light R is set by the difference in the amount of light of the first and second auxiliary lights A1 and A2 to be read later (step S170). That is, the incident angle of the reference light R may be calculated by comparing the amounts of light of the first and second auxiliary lights A1 and A2 that are incident together with the reference light R. In this case, in the comparison between the first and second auxiliary lights A1 and A2, the incident angle of the reference light R may be selected as a position where there is no difference or the least difference between the first and second auxiliary lights A1 and A2.

Hereinafter, the measurement of the first and second auxiliary light by the auxiliary light reader will be described with reference to FIGS. 5A to 5B.

5A to 5B are exemplary views illustrating detection of auxiliary light in a method of reproducing an optical information storage medium according to the present invention.

First, the first auxiliary light A1 and the second auxiliary light A2 passing through the storage medium D are sensed by the auxiliary light reader 176. The auxiliary light reader 176 is composed of a plurality of photodiodes P1... Pn, and each photodiode P1... Pn is partitioned into a plurality of sensing units U1... Un. .

The sensing units U1 ... Un detect the first and second auxiliary lights A1 and A2 that have passed through the storage medium D, and the first and second auxiliary lights U1 ... Un of the sensing units U1 ... Un are detected. The detection unit U1 having the maximum detection value for detecting A1 and A2 and the detection unit U2 having the second detection value are found. The detection unit U1 having the maximum detection value and the detection unit U2 having the second detection value are found, and then the values of each detection unit U1 and U2 are compared with each other.

On the other hand, it is necessary to set the detection unit Un when the first and second auxiliary lights A1 and A2 are respectively incident on exactly one photodiode Pn, and one auxiliary light A1 or A2 is two. This is because the case where the light is incident on the photodiodes Pn and Pn + 1 may be incident simultaneously.

That is, when the first and second auxiliary lights A1 and A2 are sensed by one photodiode Pn as shown in FIG. 5A and the first and second auxiliary lights A1 and A2 as shown in FIG. 5B, respectively. One or more of these may occur when the auxiliary light is sensed by overlapping the plurality of photodiodes Pn and Pn + 1.

Accordingly, when one auxiliary light of one of the first and second auxiliary lights A1 and A2 is detected by one photodiode, the largest detection value among the photodiodes P1... Pn arranged in the auxiliary light reader 176 is first detected. Find a photodiode (hereinafter referred to as "P2"). Based on this P2, the first sensing unit (U1) is set together with two photodiodes located on both sides, and based on this, three peripheral photodiodes are grouped into one unit and these sensing units (U2 .. Uniting ..Un)

After that, the light quantity values in each of the sensing units U1 and U2 are calculated, and among them, the sensing unit U1 having the largest light quantity value and the sensing unit U2 having the second light quantity value are found. Thereafter, the light quantity values of the first sensing unit U1 and the second sensing unit U2 are compared.

On the other hand, even when the auxiliary light (A1, A2) is formed by overlapping one or more of the photodiodes (P1 ... Pn) as shown in Figure 5b, the auxiliary light (A1, A2) is formed on one photodiode When the photodiodes P1... Pn are sensed units U2... Un in the same manner as described above, accurate light intensity of the first and second auxiliary lights A1 and A2 can be measured.

In addition, the distance d between the first and second auxiliary lights A1 and A2 sensed by the auxiliary light reader 176 is measured. The distance between the first and second auxiliary lights A1 and A2 can be obtained by calculating the distance between the photodiode for detecting the largest light intensity and the photodiode for detecting the next light intensity, and the detected first and second light sources. The distance between the auxiliary lights A1 and A2 may be determined by comparing the distance between the first and second auxiliary lights A1 and A2.

The reason for measuring the distance between the first and second auxiliary lights A1 and A2 is that the auxiliary light of any one of the first and second auxiliary lights A1 and A2 when the inclination of the storage medium D is excessively inclined. Occasional departures from the region of the auxiliary light reader 176 may occur. In this case, the auxiliary light reader 176 may detect any one of the auxiliary light detected and the other light detected by the auxiliary light reader 176 (eg, noise light generated during diffraction) as the auxiliary light.

Although described in detail with respect to preferred embodiments of the present invention as described above, those of ordinary skill in the art, without departing from the spirit and scope of the invention as defined in the appended claims Various modifications may be made to the invention. Therefore, changes in the future embodiments of the present invention will not be able to escape the technology of the present invention.

For example, the optical information reproducing apparatus, the optical information recording and reproducing apparatus, and the optical information reproducing method using the same may be implemented by adding a component having another additional function or by replacing with another component. However, all other modified embodiments include the essential elements of the present invention should be considered to be included in the technical scope of the present invention.

As described above, according to the optical information reproducing apparatus, the optical information recording and reproducing apparatus according to the present invention, and the optical information reproducing method using the same, the reference light and each of the reference light passing through the storage medium and passing the reference light and the pair of auxiliary light through the storage medium, respectively. When the auxiliary light is detected and the data of the storage medium is reproduced, it is possible to detect whether a tilt error occurs and correct it.

Claims (18)

Light source; A light splitter separating the light emitted from the light source into reference light and temporary light; An auxiliary light separator for separating the temporary light to form a pair of auxiliary lights; An incident optical system for incident the reference light and the auxiliary light onto a storage medium storing optical information; A reproduction light reader which reads out the reproduction light reproduced by the reference light and sets the signal area with the reproduction light emitting the maximum amount of light out of the reproduction light as a reference position; And And an auxiliary light reader configured to set the incident angle of the reference light by comparing the light intensities of the pair of auxiliary lights incident to the signal region. The method of claim 1, And the auxiliary lights are incident on the storage medium by being inclined at corresponding angles at different positions with respect to the reference light. The method of claim 2, And the optical information recorded on the storage medium is a holographic interference fringe, and the auxiliary light is incident to a position where the reference light is incident and diffracted together with the reference light. The method of claim 1, The reference light and the auxiliary light is incident to the same point of the storage medium, the optical information further comprises a read light splitter for separating the reproduction light reproduced from the storage medium and the auxiliary light transmitted through the storage medium; Playback device. The method of claim 4, wherein And the auxiliary light reader includes a plurality of photodiodes arranged in a tilting direction in which the reference light is controlled. The method of claim 5, And a length at which the photodiode is arranged is greater than a sum of the distance between the incident points of the auxiliary lights and the moving distance of the incident points in the tilting control of the reference light. Light source; A non-polarization light splitter that separates light emitted from the light source; A signal light optical system for loading data into one light separated by the non-polarization light splitter to form a signal light and to enter the storage medium; A polarized light splitter that separates the remaining light separated by the non-polarized light splitter into a reference light and a temporary light; An auxiliary light separator configured to diffuse and separate the separated temporary light at an angle symmetrical with respect to an optical axis of the temporary light to form a plurality of auxiliary lights; An incident optical system for incident the reference light and the auxiliary light onto a storage medium storing optical information; A reproduction light reader which reads out the reproduction light reproduced by the reference light and sets the signal area with the reproduction light emitting the maximum amount of light out of the reproduction light as a reference position; And And an auxiliary light reader for comparing the light intensities of the pair of auxiliary lights incident to the signal region to set an incident angle of the reference light. The method of claim 7, wherein And the auxiliary lights are incident on the storage medium by being inclined at corresponding angles at different positions with respect to the reference light. The method of claim 8, And the optical information recorded on the storage medium is a holographic interference fringe, and the auxiliary light is incident to a position where the reference light is incident and diffracted together with the reference light. The method of claim 7, wherein The reference light and the auxiliary light is incident to the same point of the storage medium, the optical information further comprises a read light splitter for separating the reproduction light reproduced from the storage medium and the auxiliary light transmitted through the storage medium; Record and playback device. The method of claim 10, And the auxiliary light reader includes a plurality of photodiodes arranged in a tilting direction in which the reference light is controlled. The method of claim 11, And a length at which the photodiode is arranged is greater than a sum of the distance between the incident points of the auxiliary lights and the moving distance of the incident points in the tilting control of the reference light. Injecting the reference light into a storage medium storing the multiplexed optical information; Tilting the reference light to scan the multiplexed optical information; Finding a reference position emitting the maximum amount of light by the reference light in the scanned light information; Setting a signal area based on the reference position; Injecting a pair of auxiliary light into the signal region at the same position as the reference light; Measuring an amount of light of each auxiliary light; And comparing the amount of light of each of the auxiliary lights with each other to set an angle of incidence of the reference light. The method of claim 13, And the auxiliary lights are inclined at corresponding angles at different positions to be incident on one point of the storage medium. The method of claim 14, The measurement of the auxiliary light is performed by a plurality of photodiodes extending to the movement region of the auxiliary light. The method of claim 15, The photodiodes are divided into a plurality of sensing units, The light intensity of the auxiliary light measured in the sensing unit is calculated by adding to the photodiode forming the sensing unit. The method of claim 16, And comparing the sensing unit having the largest sensing value among the sensing units with the sensing unit having the second largest sensing value and reading the slope of the storage medium. The method of claim 13, The step of setting the incident angle of the reference light, the optical information reproducing method, characterized in that it is set in a direction in which the difference in the amount of light of the respective auxiliary light decreases.

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