KR20070090578A - Optical information reproducing apparatus, optical information recoding/reproducing apparatus and method of optical information reproducing using the same - Google Patents

Abstract

An optical information reproducing apparatus, optical information recording/reproducing apparatus, and optical information reproducing method using the same are provided to use an assist beam in order to control the incident position of a reference beam. A beam is emitted(S110). The beam is split into a reference beam and an assist beam(S120). The assist beam is split into a plurality of assist beams(S130). The assist beam and the reference beam overlap with each other with respect to a parallel beam axis(S140). The overlapping assist beam and reference beam are incident on a storage medium(S150). The intensity and the position of the assist beam passing through the storage medium are read(S160). The incident angle of the reference beam is controlled according to the information of the assist beam(S170).

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 of optical information reproducing using the same}

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

2 is a simplified diagram showing an auxiliary optical split optical system in an optical information reproducing apparatus according to an embodiment of the present invention.

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

4A to 4B are graphs showing angular selectivity according to the amount of light in the optical information reproducing apparatus according to the embodiment of the present invention.

5 is a schematic diagram showing an optical information recording and reproducing apparatus according to another embodiment of the present invention.

6 is a schematic diagram showing an optical information recording and reproducing apparatus according to another embodiment of 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 optical separation optical system

140: superposition optical system

160: focus optical system

170: reading optical system

The present invention relates to an optical information reproducing apparatus, and more particularly, to an optical information reproducing apparatus, an optical information recording and reproducing apparatus, and an optical information reproducing method using the same, which can provide an auxiliary light for reading the incident position of the reference light. .

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.

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. As a result, the diffraction efficiency of the light may continuously change.

Furthermore, in the case of the volume hologram as described in the patent, the reproduction efficiency of the reproduction light is excellent only when the reference light is incident on the volume holographic region having sharp angular selectivity. Otherwise, if the incident angle of the reference light deviates only a little from the Bragg angular, the light exits the volume hologram region, and thus the diffraction efficiency of the reference light drops sharply.

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 to provide an auxiliary light for controlling the incident position of the reference light when the optical information is reproduced.

Another object of the present invention is to provide an optical information recording and reproducing apparatus which provides an auxiliary light for controlling the incident position of the reference light when the optical information is reproduced.

Another object of the present invention is to provide an optical information reproducing method using auxiliary light to control the incident position of the reference light when the optical information is reproduced.

An optical information reproducing apparatus according to the present invention for achieving the above object, the light source; A polarized light splitter that separates the light emitted from the light source into a reference light and an auxiliary light source; An auxiliary optical separation optical system for diffusing and separating the separated auxiliary light sources at an angle symmetric with respect to an optical axis of the auxiliary light source to form a plurality of auxiliary lights; An incident optical system in which the reference light and the auxiliary light are superimposed on a parallel optical axis and incident at the same position on a storage medium in which optical information is stored; And a reading unit which detects reproduction light reproduced in the storage medium by the reference light, reads an auxiliary light passing through the storage medium, and reads an incident angle of the reference light.

The auxiliary light split optical system includes: an auxiliary light source expander for expanding the width of the auxiliary light source; And an auxiliary light separator for separating the auxiliary light source expanded by the expander into a plurality of auxiliary lights having the same light quality.

Preferably, the auxiliary light splitter is a prism of a reverse conical shape having a symmetrical cross section to diffusely separate the incident auxiliary light source.

The incident optical system may include: an overlapping optical system for allowing the auxiliary light to pass and refracting the reference light to overlap the auxiliary light with the reference light so as to have a parallel optical axis; And a focusing optical system for allowing the superimposed light and the reference light to be incident on the storage medium at the same position.

Between the overlapping optical system and the focusing optical system, the reference light and the auxiliary light superimposed in the overlapping optical system refracting to pass through the focusing optical system to adjust the incident angle of the reference light and the auxiliary light incident on the storage medium and the galvan It is preferable that a no mirror be further provided.

The reading unit may include: a read light splitter configured to separate the reproduced light reproduced from the storage medium and an auxiliary light transmitted through the storage medium; A reproduction light reader for reading the reproduction light separated by the read light splitter; It is preferable to include an auxiliary light reader for reading the auxiliary light separated by the read light splitter.

The information of the auxiliary light read by the auxiliary light reader is preferably the intensity and position of the auxiliary 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 polarization light splitter that separates the remaining light separated from the non-polarization light splitter into a reference light and an auxiliary light source; An auxiliary optical separation optical system for diffusing and separating the separated auxiliary light sources at an angle symmetric with respect to an optical axis of the auxiliary light source to form a plurality of auxiliary lights; An incident optical system in which the reference light and the auxiliary light are superimposed on a parallel optical axis and incident at the same position on a storage medium in which optical information is stored; And a reading unit which detects reproduction light reproduced by the storage medium by the reference light, reads an auxiliary light passing through the storage medium, and reads an incident angle of the reference light.

The signal optical system includes: a light source adjusting member configured to polarize one light separated by the non-polarization light splitter to form signal light; A spatial light modulator for loading data into the signal light; And a Fourier transform lens for injecting the signal light loaded with data into the storage medium.

Preferably, a shutter member is further provided to block the signal light when the storage medium is reproduced.

Preferably, a shutter member is further provided to block the auxiliary light source when recording the storage medium.

The auxiliary light split optical system includes: an auxiliary light source expander for expanding the width of the auxiliary light source; And an auxiliary light separator for separating the auxiliary light source expanded by the expander into a plurality of auxiliary lights having the same light quality.

Preferably, the auxiliary light separator is an inverted conical prism having a symmetrical cross section to diffusely separate the incident auxiliary light source.

The incident optical system may include: an overlapping optical system for allowing the auxiliary light to pass and refracting the reference light to overlap the auxiliary light with the reference light so as to have a parallel optical axis; And a focusing optical system for allowing the superimposed light and the reference light to be incident on the storage medium at the same position.

Between the overlapping optical system and the focusing optical system, the reference light and the auxiliary light superimposed in the overlapping optical system refracting to pass through the focusing optical system to adjust the incident angle of the reference light and the auxiliary light incident on the storage medium and the galvan It is preferable that a no mirror be further provided.

The reading unit may include: a read light splitter configured to separate the reproduced light reproduced from the storage medium and an auxiliary light transmitted through the storage medium; A reproduction light reader for reading the reproduction light separated by the read light splitter; It is preferable to include an auxiliary light reader for reading the auxiliary light separated by the read light splitter.

The information of the auxiliary light read by the auxiliary light reader is preferably the intensity and position of the auxiliary light.

Optical information reproduction method according to the present invention for achieving the above object, the light emitting step of emitting a light source; Splitting the emitted light into a reference light and an auxiliary light source; An auxiliary light splitting step of dividing the divided auxiliary light sources into a plurality of auxiliary lights; An optical overlapping step of overlapping the divided auxiliary light and the reference light with parallel optical axes; An incident step of injecting the superimposed light and the reference light into a storage medium; An auxiliary light reading step of reading the intensity and position of the auxiliary light passing through the storage medium; And controlling the incident angle of the reference light according to the information of the auxiliary light to be read.

The incidence step is; It is preferable to further include a refracting step of refracting the reference light and the auxiliary light superimposed in the optical overlapping step toward the storage medium by a refraction mirror.

In the refraction step, the angle of incidence of the reference light is controlled by controlling the refraction mirror in accordance with the information of the auxiliary light read in the auxiliary light reading step.

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 some modified configuration of the drawings are employed, it can be seen as an equivalent configuration if the functional similarity and identity. .

First, the optical information reproducing apparatus according to the present invention will be described with reference to FIGS.

1 is a block diagram showing an optical information reproducing apparatus according to an embodiment of the present invention, Figure 2 is a simplified diagram showing an auxiliary optical separation optical system in the optical information reproducing apparatus according to an embodiment of the present invention. Here, the optical information reproducing apparatus in this embodiment may be a device for reproducing optical information recorded with a holographic interference fringe.

As shown, the optical information reproducing apparatus 100 according to an embodiment of the present invention, the light source 110 for generating light (L), and the light (L) generated from the light source 110, the reference light (S) And an auxiliary light splitting optical system 130 for separating the auxiliary light source A separated by the auxiliary light source A and the auxiliary light source A separated from the polarizing light splitter 120 into a pair of auxiliary lights A1 and A2. In the superposition optical system 140 and the superposition optical system 140 to superimpose the auxiliary light A1 and A2 separated by the auxiliary optical split optical system 130 and the reference light S separated by the polarized light splitter 120 into parallel optical axes. Focus optical system 160 for injecting the auxiliary light (A1, A2) and the reference light (S) superimposed on the parallel optical axis to the storage medium (D), and the reference light (S) and auxiliary light (A1,) incident on the storage medium (D) A reading optical system 170 for reading A2) is 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 separates the light L generated by the light source 110 into a reference light S for reproducing optical information and an auxiliary light source A for generating auxiliary lights A1 and A2. The polarization splitting surface 120a has a polarization splitting surface 120a that polarizes and splits incident light L in a structure in which two or more kinds of materials having different refractive indices are repeatedly deposited. The polarization splitting surface 120a has an auxiliary light source (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 S and the 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 or a photosensitive filter. The light source adjusting member 124 may be installed when precise adjustment of the intensity, uniformity, etc. of the reference light S and the auxiliary lights A1 and A2 is required. If the characteristics of the reference light (S) and the auxiliary light source (A) is guaranteed, it may not be installed.

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 S and the auxiliary light source A divided by the non-polarization light splitter into S polarization and P polarization, respectively. Since various implementations can be changed, detailed description thereof will be omitted.

The auxiliary optical split optical system 130 is for separating the auxiliary light source A separated by the polarized light splitter 120 into a pair of auxiliary lights A1 and A2 for sensing in the read optical system 170 to be described later. As shown in FIG. 2, the auxiliary light source expander 132 is provided on a path through which the auxiliary light source A passes and expands the width of the auxiliary light source A, and the auxiliary light source A having a wider width includes a pair of auxiliary lights ( The auxiliary light separator 134 which separates into A1 and A2 is provided.

Here, the auxiliary light source expander 132 is composed of a plurality of lenses to expand the incident light source (A) incident to a size suitable to separate into a pair of auxiliary light (A1, A2), which is that in the auxiliary light separator (134) This is because the light is separated into a pair of auxiliary lights A1 and A2 in a reduced state.

The auxiliary light separator 134 separates the auxiliary light source A extended by the auxiliary light source expander 132 into a pair of auxiliary lights A1 and A2 having the same optical quality. It is preferred to be provided with a reverse conical prism that diffuses and separates at an angle. In addition, the auxiliary light separator 134 is further provided with a separate light blocking member (not shown) between the auxiliary light (A1, A2) to be separated in order to prevent the emission of light generated when the auxiliary light (A1, A2) is separated. Can be.

Referring back to FIG. 1, the reference light S separated by the polarization light splitter 120 is incident to the superposition optical system 140, which will be described later, by the plurality of reflection 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 superimposition optical system 140 is for superimposing a pair of the auxiliary light A1 and A2 and the reference light S in parallel optical axes, and overlaps the auxiliary light A1 and A2 with the reference light S. 142, the refraction mirror 150 for refracting the reference light S superimposed by the optical overlapper 142 and the pair of auxiliary lights A1 and A2 with a focusing optical system to be described later, and the tip of the optical overlapping machine 142. And a plurality of focusing lenses 146 provided at the rear end.

Here, the optical overlapper 142 is an overlapping surface for passing through the auxiliary light (A1, A2) incident in a structure in which two or more kinds of materials having different refractive indices are repeatedly deposited, and at the same time reflects the incident reference light (S) ( 142a) is formed.

Meanwhile, as described above, the reference light S and the auxiliary lights A1 and A2 superimposed by the optical overlapper 142 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 S and the auxiliary lights A1 and A2.

The focus optical system 160 allows the reference light S and the auxiliary lights A1 and A2 reflected by the refractive mirror 150 to enter the storage medium D, and includes a plurality of focus lenses 162. On the other hand, it is preferable that the lengths of the optical paths of the auxiliary lights A1 and A2 passing through the focusing optical system have the same length as possible. In addition, the intensities of the auxiliary lights A1 and A2 incident on the storage medium D should be as identical as possible or within an error range.

The read optical system 170, the read light splitter 172 for separating the reproduction light formed by the reference light (S) incident on the storage medium (D) and the auxiliary light (A1, A2) passing through the storage medium (D). ), A reproducing light reader 174 which reads out the reproduced light separated by the read light splitter 172, and an auxiliary light reader 176 which reads the auxiliary lights A1 and A2 separated by the read light splitter 172). It is provided.

Here, the read light splitter 172 is for separating the auxiliary light (A1, A2) passing through the storage medium (D) and the reproduction light reproduced while the reference light (S) passes through the storage medium (D), Auxiliary light (A1, A2) is passed through the incident light to the auxiliary light reader 176, the reference light (S) is reflected and incident to the reproduction light reader 174 in a structure in which two or more kinds of materials having different refractive indices are repeatedly deposited.

The reproducing light reader 174 detects reproducing light reproduced by the reference light S 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 auxiliary lights A1 and A2 diffracted together with the reference light S when the optical information is reproduced by the reference light, Accordingly, to determine the diffraction efficiency of the reference light S, a plurality of photodiodes or a single CCD (or CMOS) having a low density pixel combination arranged in the rotation direction of the refractive mirror 150 may be adopted.

On the other hand, the photodiode or CCD (or CMOS) or the like used as the auxiliary light reader 176 should be formed larger than the scanning distance of the auxiliary lights A1 and A2 incident on the auxiliary light reader 176 by the refractive mirror 150. In addition, a separate analog / digital converter may be used to digitize the detected value. Since various embodiments are possible, detailed description thereof will be omitted.

The intensity and position of the auxiliary lights A1 and A2 detected by the auxiliary light reader 176 are used to determine the diffraction efficiency of the reference light, and the refraction mirror provided by the galvano mirror according to the diffraction efficiency of the reference light S. It is provided to rotate the 150 to adjust the incident angle of the reference light (S).

Accordingly, the operation of the optical information reproducing apparatus according to an embodiment of the present invention will be described in detail with reference to the embodiment. Each element mentioned below should be understood with reference to the above description and FIGS. 1 to 2.

3 is a flowchart illustrating a method of reproducing optical information of an optical information reproducing apparatus according to an embodiment of the present invention, and FIGS. 4A to 4B are angular selectivity according to the amount of light in the optical information reproducing apparatus according to an embodiment of the present invention. Is a graph.

First, light L is emitted from the light source 110 to reproduce the optical information (step S110). The light (L) emitted therefrom is separated into the reference light (S) and the auxiliary light source (A) by the polarized light splitter 120, the separated reference light (S) and the auxiliary light source (A) is a light source control member 124 The characteristic (for example, intensity, uniformity, polarization, etc.) is adjusted by this (step S120).

Then, the adjusted auxiliary light source A is separated into a pair of auxiliary lights A1 and A2 by the auxiliary light splitting optical system 130. At this time, the auxiliary light source (A) is separated into a pair of auxiliary light (A1, A2) in which the width is reduced by the auxiliary light separator 134 in the state that the width is extended by the auxiliary light source expander 132 of the auxiliary light split optical system 130. (Step S130).

Meanwhile, the pair of auxiliary lights A1 and A2 separated as described above are incident to the superposition optical system 140 to overlap with the reference light S (step S140). Auxiliary light (A1, A2) incident to the superposition optical system 140 is superimposed on the optical axis parallel to the reference light (S) and proceeds to the refractive mirror 150, the reference light (S) and the reference light (S) by the refractive mirror 150 Auxiliary light (A1, A2) superimposed on the () is incident on the storage medium (D) (step S150).

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

Thereafter, the pair of 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 the position of the detected auxiliary light A1 and A2 (step S160).

The intensity and position information of the auxiliary lights A1 and A2 sensed by the auxiliary light reader 176 are used as data for controlling the angle of incidence of the reference light S incident on the storage medium D by the refraction mirror 150. (Step S170).

On the other hand, the step of measuring the light intensity of the above-described auxiliary light will be described with reference to Figures 4s to 4b. 4A to 4B are graphs showing angular selectivity according to the intensity of light in the optical information reproducing apparatus according to the present invention. FIG. 4A shows a normal state of incidence angles of the reference light and the auxiliary light. 4b shows a state in which an error occurs between the reference light and the auxiliary light. Here, it is assumed that the light intensity of the reference light and the auxiliary light incident on the storage medium is the same.

As shown in FIG. 4A, when the intensities of the light of the first auxiliary light A1 and the second auxiliary light A2 incident at the same angle are located at the same position on both inclined surfaces of the peak curve, the diffraction efficiency of the reference light P is the most. Because of its size, the reference light P is located at the peak (the angle of incidence of the reference light is "Bragg angular").

On the other hand, when the reference light P is not a peak and the diffraction efficiency is not a peak as shown in FIG. 4B, the first auxiliary light A1 is located further below the reference light R in the curve, and the second auxiliary light ( A2) is rather close to the peak.

That is, in the case of FIG. 4B, since the incident angle of the reference light P is shifted to the left, the incident light intensity of the reference light P may be tilted to the right to obtain more improved light intensity of the reference light P.

This determination can be obtained by measuring the light intensity of the pair of auxiliary lights A1 and A2 sensed by the auxiliary light reader 176. That is, the diffraction efficiency of the reference light P can be obtained by comparing the intensity of the light with respect to the first auxiliary light A1 and the second auxiliary light A2 by measuring it in the auxiliary light reader 176, and in the embodiment of the present invention, The determination of the incident angle control of the reference light P is performed based on the data obtained at this time.

5 to 6, an optical information recording and reproducing apparatus according to the present invention will be described.

FIG. 5 is a schematic diagram showing an optical information recording and reproducing apparatus according to another embodiment of the present invention, and FIG. 6 is a schematic diagram showing an optical path when recording optical information, and FIG. 6 shows an optical information recording and reproducing apparatus according to another embodiment of the present invention. Fig. 1 is a schematic diagram showing the optical path when optical information is reproduced.

The optical information recording and reproducing apparatus 200 to be described below is an optical system for generating the signal light P for recording the 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.

As shown in FIGS. 5 to 6, the optical information recording and reproducing apparatus 200 according to the present invention separates the light source 210 for generating light L and the light L generated by the light source 210. In the non-polarization light splitter 220a, the polarization light splitter 220b for separating the auxiliary light source A from the light L separated from the non-polarization light splitter 220a, and the polarization light splitter 220b. In the auxiliary light splitting optical system 230 for separating the separated auxiliary light source A into a pair of auxiliary light beams A1 and A2, and in the auxiliary light beams A1 and A2 and the polarized light splitter 220b separated from the auxiliary light splitting optical system 230, The superposition optical system 240 overlapping the separated reference light S, the refraction mirror 250 limiting the paths of the auxiliary lights A1 and A2 and the reference light S superimposed in the superposition optical system 240, and the refraction mirror ( A focusing optical system 260 for injecting the auxiliary light A1 and A2 and the reference light S refracted by the light into the storage medium D, and the reference light S and the auxiliary light A1, incident to the storage medium D. Plate A2) And a read optical system 270.

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

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

Here, a light source control member 221 is further provided between the non-polarization light splitter 220a and the polarization light splitter 220b to convert optical characteristics of the temporary light A split by the non-polarization light splitter 220a. The light source control member 221 may be provided with a λ / 2 wave plate.

In addition, 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 crystal (LC), polymer dispersion (PDLC; Polymer) Dispersed Liquid Crystal, and plasma address liquid crystal (PALC) may be employed.

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

First, 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 P and the reference light S, and one light is a light source adjusting member. Polarized by P 222a to be converted into signal light P. FIG.

The signal light P thus converted is loaded by the spatial light modulator while passing through the spatial light modulator 228, and the signal light P loaded with data is incident on the storage medium D by the Fourier lens 229. do.

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

Meanwhile, the reference light S separated from the polarized light splitter 220b is incident to the superposition optical system 240 by the plurality of reflection mirrors 226, and the reference light S 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 P and the reference light S incident on the storage medium D. This holographic interference fringe is data for reproducing the storage medium (D).

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

First, 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 P and the reference light S. However, one light for generating the signal light P is blocked by the shutter 224a so that its progress is limited.

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

On the other hand, the auxiliary light source (A) separated by the polarized light splitter (220b) is separated into a pair of auxiliary light (A1, A2) by the auxiliary light separation optical system 230, the separated pair of auxiliary light (A1, A2) is superimposed optical system The light is incident on the light source 240 and overlaps the reference light S so that the path is switched by the refractive mirror 250.

Accordingly, the reference light S and the auxiliary light A1 and A2 whose paths are switched by the refractive mirror 250 are incident on the storage medium D by the focusing optical system 260, and the reference light incident on the storage medium D S) is converted into reproduction light by the interference fringe formed on the storage medium D, and the converted reproduction light and the auxiliary light A1 and A2 passing through the storage medium D are incident to the read optical system 270.

Thereafter, the reproduction light and the auxiliary light A1 and A2 incident on the reading optical system 270 are separated by the reading light separator 272 so that the reproduction light is read by the reproduction light reader 274 and the auxiliary light A1 and A2. ) Is read by the auxiliary light reader 276.

At this time, the intensity and position information of the auxiliary light (A1, A2) detected by the auxiliary light reader 276 is used as data for controlling the incident angle of the reference light (S) incident on the storage medium (D) by the refractive mirror 250. .

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 depart from the technology of the present invention.

For example, in the optical information reproducing apparatus and the optical information recording and reproducing apparatus according to the present invention, components having other additional functions are added. Or it may be replaced by another component. However, other modified embodiments include the essential components of the present invention, and if a pair of auxiliary light to control the angle of incidence of the reference light should be considered to be included in the technical scope of the present invention.

As described above, according to the optical information reproducing apparatus and the optical information recording and reproducing apparatus according to the present invention, two auxiliary lights in addition to the reference light when the optical information is reproduced are measured after passing through the optical information storage medium. By comparing the intensity and position of the auxiliary light to control the incident angle of the reference light, the diffraction efficiency of the reference light and the reproduction efficiency of the optical information can be further improved.

Claims (18)

Light source; A polarized light splitter that separates the light emitted from the light source into a reference light and an auxiliary light source; An auxiliary optical separation optical system for diffusing and separating the separated auxiliary light sources at an angle symmetric with respect to an optical axis of the auxiliary light source to form a plurality of auxiliary lights; An incident optical system in which the reference light and the auxiliary light are superimposed on a parallel optical axis and incident at the same position on a storage medium in which optical information is stored; And And a reading unit which detects the reproduction light reproduced by the storage medium by the reference light, reads the auxiliary light passing through the storage medium, and reads the incident angle of the reference light. The method of claim 1, wherein the auxiliary optical split optical system, An auxiliary light source expander for extending the width of the auxiliary light source; And And an auxiliary light separator for separating the auxiliary light source extended by the expander into a plurality of auxiliary lights having the same light quality. The method of claim 2, And the auxiliary light separator is a reverse conical prism having a symmetrical cross section to diffusely separate the incident auxiliary light source. The method of claim 1, wherein the incident optical system, An overlapping optical system for passing the auxiliary light and refracting the reference light to overlap the auxiliary light with the reference light so as to have a parallel optical axis; And And a focusing optical system for injecting the superimposed light and the reference light into the storage medium at the same position. The method according to claim 4, wherein between the superposition optical system and the focus optical system, And a galvano mirror further configured to adjust the incident angles of the reference light and the auxiliary light incident through the focusing optical system by refracting the reference light and the auxiliary light superimposed by the superposition optical system. Information player. The method of claim 1, wherein the reading unit, A read light splitter configured to separate the regenerated light reproduced from the storage medium and an auxiliary light transmitted through the storage medium; A reproduction light reader for reading the reproduction light separated by the read light splitter; And an auxiliary light reader for reading the intensity and the position of the auxiliary light separated by the read light splitter. 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 polarization light splitter that separates the remaining light separated from the non-polarization light splitter into a reference light and an auxiliary light source; An auxiliary optical separation optical system for diffusing and separating the separated auxiliary light sources at an angle symmetric with respect to an optical axis of the auxiliary light source to form a plurality of auxiliary lights; An incident optical system in which the reference light and the auxiliary light are superimposed on a parallel optical axis and incident at the same position on a storage medium in which optical information is stored; And And a reading unit which detects the reproduction light reproduced by the storage medium by the reference light, reads the auxiliary light passing through the storage medium, and reads the incident angle of the reference light. . The method of claim 7, wherein the signal optical system, A light source adjusting member for polarizing one light separated by the non-polarization light splitter to form signal light; A spatial light modulator for loading data into the signal light; And And a Fourier transform lens for injecting the signal light loaded with data into the storage medium. The method of claim 8, And a shutter member for blocking the signal light when the storage medium is reproduced. The method of claim 8, And a shutter member for blocking the auxiliary light source when recording the storage medium. The method of claim 7, wherein the auxiliary optical separation optical system, An auxiliary light source expander for extending the width of the auxiliary light source; And And an auxiliary light separator for separating the auxiliary light source extended by the expander into a plurality of auxiliary lights having the same optical quality. The method of claim 11, wherein the auxiliary light splitter And the auxiliary light separator is a reverse conical prism having a symmetrical cross section to diffusely separate the incident auxiliary light source. The method of claim 7, wherein the incident optical system, An overlapping optical system for passing the auxiliary light and refracting the reference light to overlap the auxiliary light with the reference light so as to have a parallel optical axis; And And a focusing optical system for injecting the superimposed light and the reference light into the storage medium at the same position. The method according to claim 13, wherein between the superposition optical system and the focus optical system, And a galvano mirror further configured to refract the superimposed reference light and the auxiliary light in the superimposed optical system to adjust the incident angles of the reference light and the auxiliary light passing through the focus optical system to the storage medium. Information recording and reproducing apparatus. The method of claim 7, wherein the reading unit, A read light splitter configured to separate the regenerated light reproduced from the storage medium and an auxiliary light transmitted through the storage medium; A reproduction light reader for reading the reproduction light separated by the read light splitter; And an auxiliary light reader for reading the intensity and the position of the auxiliary light separated by the read light splitter. A light emitting step of emitting a light source; Splitting the emitted light into a reference light and an auxiliary light source; An auxiliary light splitting step of dividing the divided auxiliary light sources into a plurality of auxiliary lights; An optical overlapping step of overlapping the divided auxiliary light and the reference light with parallel optical axes; An incident step of injecting the superimposed light and the reference light into a storage medium; An auxiliary light reading step of reading the intensity and position of the auxiliary light passing through the storage medium; And And controlling the incident angle of the reference light according to the information of the auxiliary light to be read. The method of claim 16, wherein the step of entering; And a refraction step of refracting the reference light and the auxiliary light superimposed in the optical overlapping step toward the storage medium by a refraction mirror. The method of claim 17, wherein the refraction step, And controlling the incidence angle of the reference light by controlling the refractive mirror according to the information of the auxiliary light read in the auxiliary light reading step.

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