KR100420135B1 - Composite volume holographic digital storage/reproducing system - Google Patents

Abstract

PURPOSE: A complicated volume holographic digital data storage/reproducing system is provided to diverge a vertically polarized recording reference light from a horizontally polarized reproducing reference light, thereby simultaneously recording holographic data on one storage medium and reproducing holographic data recorded on the other storage medium. CONSTITUTION: In a recording mode of a recording/reproducing path(P1), two shutters(108,118) are open/shut according to a control signal received from a system controller. A vertically polarized light diverged from a polarized optical splitter(104) by being created from a light source(102) is incident on an optical separator(106). The optical separator(106) separates the vertically polarized light into a recording reference light and an object light. The reference light is provided to a reference light processing path(PS1), and the diverged object light is supplied to an object light processing path(PS2).

Description

Compound Volume Holographic Digital Storage and Playback System {COMPOSITE VOLUME HOLOGRAPHIC DIGITAL STORAGE / REPRODUCING SYSTEM}

FIELD OF THE INVENTION The present invention relates to a volume holographic digital data storage / reproducing system, and more particularly to holograms on one storage medium (e.g., optical refractive crystal) in a storage and reproduction system. A multi-volume holographic digital storage and reproducing system suitable for recording data and at the same time reproducing holographic data recorded on another storage medium.

Recently, the field of technology using volume holographic digital data storage has been actively researched everywhere due to the remarkable development of semiconductor laser, charge coupled device (CCD), liquid crystal display (LCD), etc. As a result of these studies, fingerprint recognition systems for storing and reproducing fingerprints have been put to practical use, and are being expanded to various fields that can apply the advantages of large capacity and ultra-fast data transfer rate.

The volume holographic digital storage and reproducing system as described above is a storage medium, for example, a crystal, in which an interference fringe generated when the object light and the reference light from the target object are interfered with each other is sensitive to the amplitude of the interference fringe. By recording in a storage medium such as a crystal or the like, by recording the intensity and direction of the object light by a method of changing the angle of the reference light or the like, a three-dimensional image of the object can be displayed and a page composed of binary data (page Hundreds to thousands of holograms organized in units can be stored in the same location.

FIG. 2 illustrates a typical conventional volume holographic digital storage for storing three-dimensional hologram data (ie, interference fringes) in a storage medium by using interference between object light and reference light, and reproducing three-dimensional hologram data stored in the storage medium. And an overall schematic of the regeneration system.

As shown in the figure, a conventional volume holographic digital storage and reproducing system includes a light source 202 for generating laser light required in holography and a storage medium for storing three-dimensional hologram data (i.e., interference fringes). 230 (eg, a light refractive crystal), and between the light source 202 and the storage medium 230, two paths including respective optical systems, that is, the reference light processing path PS1 and the object light processing path PS2 is formed.

Referring to FIG. 2, the optical separator 204 separates the incident laser light generated from the light source 202 into the reference light and the object light, wherein the divided reference light is provided to the reference light processing path PS1 and branched. The object light is provided to the object light processing path PS2.

Next, on the reference light processing path PS1, a waste construction lens 206, a beam expander 207 of two lenses, and a reflecting mirror 208 are sequentially provided in the emission direction of the reference light, and the reference light processing path having such an optical structure. In PS1, reference light required for recording or reproducing hologram data is generated and provided to the storage medium 230.

That is, the reference light branched from the optical separator 204 is adjusted through the waste construction lens 206 and then expanded to a predetermined size through the beam expander 207, for example, a beam in the object light processing path PS2 described later. When expanded to a size sufficient to cover the size of the object light extending through the expander, this expanded reference light is transmitted to the reflector 208.

On the other hand, the reflector 208 deflects the reference light (beam) extended to a predetermined size through the beam expander 207 at a predetermined angle, for example, a recording angle during recording or a predetermined reproduction angle for reproduction. Reference light deflected at an angle or reproduction angle is provided to the storage medium 230.

At this time, the reference light used during recording or reproduction is controlled by rotating the reflector 208 to change the deflection angle θ each time binary data of each page unit is recorded. Hundreds to thousands of holograms can be stored or played back on the storage medium 230.

Here, the angle adjustment of the reflector 208 is performed by the motor 210 driven by the actuator 210, the deflection angle θ of the reference light is an angle measuring device (for example, attached to a predetermined portion of the motor). , Encoder).

On the other hand, on the object light processing path PS2, a reimaging lens 214, a beam expander 216, a reflector 218, a beam expander 220, and a spatial light modulator 222 are sequentially provided in the emission direction of the object light. In addition, a field lens 224 and a Fourier lens 226 are sequentially provided between the spatial light modulator 222 and the storage medium 230. In the object light processing path PS2 having such an optical structure, In recording, the storage medium 230 stores signal light (modulated object light) obtained by modulating the object light in units of one page of light and dark binary data constituting pixels according to external input data applied to the spatial light modulator 222. To provide.

That is, the object light branched from the optical separator 204 is reimaged through the reimaging lens 214, and firstly expanded to a predetermined size through the beam expander 216. Reflected through 218 at a predetermined deflection angle. The primary extended object light reflected by the reflector 218 is then second extended through the beam expander 220 and then transmitted to the spatial light modulator 222 (eg, LCD).

At this time, extending the object light to a predetermined size through the two beam expanders 216 and 220 is a source of laser light from the light source 202 and the size of the object light branched through the light separator 204 is very small, the spatial light modulator 222 This is because it is inadequate to perform light modulation, and thus the object light is extended to a size corresponding to the size of the spatial light modulator 222 through this second-order expansion.

On the other hand, the spatial light modulator 222 modulates the extended object light transmitted from the beam expander 220 in units of one page of binary data of light / dark data formed by pixels according to data input from the outside. When the data is image data in units of one frame of the image, the extended object light incident on the spatial light modulator 222 is modulated in units of one frame.

Then, the signal light modulated in units of one page of binary data output from the spatial light modulator 222 is adjusted to be suitable for storage in the storage medium 230 through the field lens 224 and the Fourier lens 226. Then, the light is incident on the storage medium 230 in synchronization with the reference light incident on the reflector 208 of the reference light processing path PS1.

Therefore, in the storage medium 230, in the recording mode, the signal light provided from the Fourier lens 226 is obtained through the interference between the recording reference light incident from the reflector 208 with the corresponding deflection angle θ. Interference fringes are recorded. That is, the light induced phenomenon of the kinetic charge occurs in the storage medium 230 according to the intensity of the interference fringe obtained by the interference between the signal light and the recording reference light. An interference fringe of the hologram data is recorded.

Further, in the storage medium 230, in the reproducing mode, the recorded interference fringe diffracts the reproducing reference light when the reproducing reference light is incident from the reflecting mirror 208 at a predetermined deflection angle [theta]. Demodulate one page of binary data (that is, a checkered pattern) composed of light and dark.

Therefore, in the reproducing mode, the image is reimaged through the reimaging lens 232 on a three-dimensional demodulated image in units of one page of binary data reproduced from the storage medium 230, and then CCD (Charge Coupled Device: 234) or the like. By irradiation, the original data, i.e., the electric signal, is restored. At this time, the reference light used to reproduce the data recorded in the storage medium 230 should be a reference light having substantially the same angle as the reference light applied when recording the hologram data in the storage medium 230.

On the other hand, in recent years, as a television for satisfying various needs of a user, for example, a composite television having two tuners has been developed and spread. In such a composite television having two tuners, a single tuner is provided. The user may tune and watch a desired broadcast channel, and may record another broadcast channel broadcast at the same time through another tuner. In other words, when a user wants to watch a program of two broadcasting channels broadcasted at the same time, one TV program can watch a broadcast program while the other broadcast program is recorded and watched. It satisfies user needs.

Therefore, in view of the above, if it is possible to mount two storage media in a volume holographic digital storage and reproduction system, record hologram data in one storage medium, and reproduce hologram data recorded in another storage medium, As a result, user convenience may be improved.

For example, assuming that there is hologram data to be recorded on one storage medium and that there is hologram data to be played back on another storage medium, recording and reproducing of the data by causing both storage media to simultaneously record and reproduce data And the total time required for regeneration can be significantly reduced.

However, in the conventional storage and reproducing system as described above, there is currently no consideration in terms of a technique related to simultaneously recording and reproducing hologram data in two storage media as described above.

Accordingly, the present invention has been made in view of the above-mentioned point, and it divides the vertically polarized recording reference light and the horizontally polarized reproducing reference light, records hologram data in one storage medium, and simultaneously records the data in another storage medium. The objective is to provide a complex volume holographic digital storage and playback system capable of reproducing hologram data.

In order to achieve the above object, the present invention, the laser light generated by the light source is divided into the reference light and the object light, and the target hologram data by interfering the branched reference light with the signal light obtained by the modulation between the branched object light and the input data A volume holographic digital storage and reproducing system for recording a recording medium into a storage medium, the volume holographic digital storage and reproducing system comprising: a polarizing light separator for generating a vertically polarizing beam for recording and a horizontally polarizing beam for reproduction by vertically and horizontally polarizing a laser beam generated from the light source; A first shutter for selectively opening and closing the emission of the horizontally polarized beam corresponding to the setting mode of the system; In the recording operation, the vertically polarized beam is branched into reference light and object light, and the vertically polarized reference light having a predetermined predetermined deflection angle and signal light generated through modulation between the branched object light and external input data are removed. 1, recording the desired hologram data by entering the storage medium, and during the reproduction operation, the branched object light is blocked and the branched reference light that is vertically deflected is incident on the first storage medium at a predetermined predetermined deflection angle. A recording and reproducing path for reproducing the recorded recorded hologram data; A second shutter for selectively opening and closing output of data reproduced from the first storage medium in correspondence with a setting mode of the system; In the reproducing operation, the target hologram recorded in the second storage medium is generated by reflecting the horizontally polarized beam incident from the first shutter into the second storage medium by reflecting it to the reproduction reference light having a predetermined deflection angle. A reproduction path for reproducing data; Optical output selecting means for selecting an output of reproduction hologram data reproduced in the first storage medium and provided through the opening of the second shutter or reproduction data reproduced in the second storage medium in a reproduction operation; And a CCD for converting the regenerated hologram data selected and exited from the light output selecting means into an electrical signal in a reproducing operation.

1 is an overall schematic diagram of a complex volume holographic digital storage and playback system in accordance with a preferred embodiment of the present invention;

2 is an overall schematic diagram of a typical conventional volume holographic digital storage and playback system.

<Description of the code | symbol about the principal part of drawing>

102 light source 104 polarized light separator

106,156 Optical Separator 108,118,138,142 Shutter

110,144: Waist configuration lens 112,122,126,146: Beam expander

114,124,148 Reflector 116,150 Actuator

120,140,154: reimaging lens 128: spatial light modulator

130: field lens 132: Fourier lens

136,152 storage medium 158 CCD

160: shielding film

The above and other objects and various advantages of the present invention will become more apparent from the preferred embodiments of the present invention described below with reference to the accompanying drawings by those skilled in the art.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 illustrates an overall schematic diagram of a complex volume holographic digital storage and playback system in accordance with a preferred embodiment of the present invention.

As shown in the figure, the most essential technical aspect of the present invention is provided with one storage medium in each of the recording and reproducing paths and the reproducing paths, and when recording and reproducing are to be performed in the two storage media, the light source is separated from the light source. The generated laser light is split into two reference lights, that is, the laser light is vertically polarized to generate the recording reference light, and the laser light is horizontally polarized to generate the reference light for reproduction, and the recording reference light generated here is one storage medium. It is transmitted to the recording and reproducing path, which is used for recording in the hologram data, and the reference light for reproduction is transmitted to the reproducing path having another storage medium newly constructed according to the present invention, and used for reproducing the hologram data.

The composite storage and reproducing system of the present invention has a recording mode, a reproducing mode, and a composite mode (i.e., a mode for simultaneously performing recording and reproduction). In FIG. 1, P1 represents a recording and reproduction path through which vertically polarized light is emitted, and P2 represents a reproduction path through which horizontally polarized light is emitted.

Here, the recording and reproducing path P1 configured on the exit side of the shutter 108 has a structure substantially the same as that of the conventional system described above.

In addition, the reproduction output path includes an optical separator 156 disposed between the reimaging lens 140 and the CCD 158, and the optical separator 156 is used in the storage medium 136 of the recording and reproduction path P1. The reproduction of the above-described conventional system except that the reproduced hologram data is transferred to the CCD 158 and the hologram data reproduced in the storage medium 152 of the reproduction path P2 is reflected to the CCD 158. It is almost identical to the output path.

On the other hand, the reproduction path P2 is a signal processing path newly added according to the present invention, and the shutter 142, the waste configuration lens 144, two in the direction in which the horizontally polarized light is emitted from the polarized light separator 104. It consists of a beam expander 146 of four lenses, a reflector 148 having an actuator 150, a storage medium 152 and a reimaging lens 154, and this reproduction path P2 is preset in the reproduction mode. Reproducing reference light having a deflection angle is generated and incident on the storage medium 152 to reproduce hologram data recorded on the storage medium 152.

Moreover, the composite storage and reproducing system of the present invention is provided so that the light (recording light or reproduction light) used in recording or reproducing data does not interfere with data recorded or to be recorded in each storage medium 136, 152. A shielding film 160 for shielding between the 136 and 152 is provided.

Referring to FIG. 1, in the recording mode in the recording and reproducing path P1, the two shutters 108, 118 are opened and the two shutters 138, 142 are blocked according to a control signal from a system controller, not shown. . Thus, the vertically polarized light generated from the light source 102 and branched at the polarized light separator 104 is incident on the light separator 106.

In this case, the optical separator 106 separates the vertically polarized light into the recording reference light and the object light, wherein the divided reference light is provided to the reference light processing path PS1 and the branched object light is the object light processing path PS2. Is provided.

Therefore, as already described in detail in the above-described conventional system, between the reference light for recording reflected at the predetermined deflection angle θ1 in the reflector 114 and the extended object light reflected by the reflector 124 and external input data Since the signal light obtained through the modulation is incident on the storage medium 136, the hologram data to be recorded is recorded in the storage medium 136.

Next, in the reproducing mode in the recording and reproducing path P1, the two shutters 108, 138 are opened and the two shutters 118, 142 are blocked in accordance with a control signal from a not shown system controller. Thus, the vertically polarized light generated from the light source 102 and branched at the polarized light separator 104 is incident on the light separator 106.

Then, the reproduction reference light branched from the optical separator 106 is transmitted to the reflector 114 via the opening of the shutter 108, the waste construction lens 110, and the beam expander 112 of two lenses.

Next, the reflector 114 uses the reproduction reference light transmitted from the beam expander 112 at a predetermined reproduction angle (that is, the deflection angle θ1 of the recording reference light used when recording the hologram data to be reproduced at present). Deflecting and entering the storage medium 136.

At this time, the reference light used at the time of reproduction is controlled by rotating the reflector 114 whenever the binary data of each page unit is recorded to change the deflection angle θ1 (angle superimposition recording technique). The angle adjustment of 114 is performed by a motor driven by actuator 116.

As a result, in the storage medium 136, when the reproduction reference light is incident at the predetermined deflection angle θ1, the recorded interference fringe is diffracted by the reproduction reference light incident on the one-page binary data composed of original pixel contrast. (I.e., checkerboard pattern), and the reproduced data demodulated therein is transmitted to the CCD 158 via the opening of the shutter 138, the reimaging lens 140, and the light separator 156.

Therefore, the three-dimensional image demodulated in units of one page of binary data in the storage medium 136 on the recording and reproduction path P1 side is restored to the original data by irradiating the CCD (Charge Coupled Device) 158. .

On the other hand, in the regeneration mode in the regeneration path P2, the shutter 142 is opened and the two shutters 108, 118 are blocked in accordance with a control signal from a system controller (not shown). Accordingly, the horizontally polarized light generated from the light source 102 and branched at the polarized light separator 104 is reflected through the aperture of the shutter 142, the waste construction lens 144 and the beam expander 146 of two lenses. Incident at 148.

Accordingly, in the reflector 148, the deflection of the recording reference light used when recording the reproduction reference light transmitted from the beam expander 146 by driving the actuator 150, that is, the hologram data to be reproduced at present. A deflection at an angle θ2 is made to enter the storage medium 152.

As a result, in the storage medium 152, when the reproduction reference light is incident at a predetermined deflection angle θ2, the recorded interference fringe is diffracted by the reproduction reference light into which the recorded interference fringe is incident. The demodulated data is reflected by the waste component lens 154 and the optical separator 156 and transmitted to the CCD 158.

Therefore, the three-dimensional image demodulated in units of one page of binary data in the storage medium 152 on the reproduction path P2 side is restored to the original data by being irradiated to the CCD (Charge Coupled Device) 158.

On the other hand, the recording mode and the reproduction mode are simultaneously executed, that is, the hologram data is recorded in the storage medium 136 on the recording and reproducing path P1 side, and at the same time, the recording medium is recorded in the storage medium 152 on the reproducing path P2 side. In the complex mode for reproducing the hologram data, the three shutters 108, 118, 142 are opened and the other shutter 138 is blocked in accordance with a control signal from a system controller (not shown).

Accordingly, the horizontally polarized light (light for data reproduction) in the polarized light separator 104 is transmitted to the reflector 148 through the opening of the shutter 142, and the vertically polarized light (light for data recording) is light. The light is transmitted to the separator 106, and the light separator 106 splits the vertically polarized light into the recording reference light and the object light so that the recording reference light is directed to the opening side of the shutter 108, and the object light is directed to the opening side of the shutter 118. Pass each one.

As a result, hologram data targeted for recording is recorded in the storage medium 136 through the same process as in the recording mode in the recording and reproducing path P1 and the reproducing mode in the reproducing path P2 described above. At the same time, the recorded hologram data for reproduction is reproduced in the storage medium 152. That is, in the composite mode according to the present invention, the recording in the storage medium 136 and the reproduction in the storage medium 152 are simultaneously performed.

As described above, according to the present invention, a composite system includes a recording and reproducing path having one storage medium and a reproducing path having another storage medium, and simultaneously performs recording and reproducing on each storage medium. In the mode, the holographic data is recorded on one storage medium by using the vertically polarized light as the reference light for recording, and the horizontally polarized light as the reference light for reproduction and simultaneously entering the respective storage media for recording and reproducing data. At the same time, the recorded hologram data can be reproduced for the purpose of reproduction in another storage medium.

Therefore, in the present invention, when recording hologram data in one storage medium and reproducing hologram data recorded in another storage medium, recording and reproduction of data are performed simultaneously, thereby requiring consumption of recording and reproduction of data. It can save a lot of time.

In addition, the present invention can improve reliability of the entire system by providing two reproduction paths, so that when an abnormality occurs in one reproduction path, the normal reproduction mode can be performed through the other reproduction path. .

Claims (4)

Volume holographic digital for splitting the laser light generated from the light source into the reference light and the object light, and interfering the signal light obtained by the modulation between the branched object light and the input data and the branched reference light to record the target hologram data in the storage medium In the storage and playback system, A polarized light separator for generating a vertical polarization beam for recording and a horizontal polarization beam for reproduction by vertically and horizontally polarizing the laser light generated from the light source; A first shutter for selectively opening and closing the emission of the horizontally polarized beam corresponding to the setting mode of the system; In the recording operation, the vertically polarized beam is branched into reference light and object light, and the vertically polarized reference light having a predetermined predetermined deflection angle and signal light generated through modulation between the branched object light and external input data are removed. 1, recording the desired hologram data by entering the storage medium, and during the reproduction operation, the branched object light is blocked and the branched reference light that is vertically deflected is incident on the first storage medium at a predetermined predetermined deflection angle. A recording and reproducing path for reproducing the recorded recorded hologram data; A second shutter for selectively opening and closing output of data reproduced from the first storage medium in correspondence with a setting mode of the system; In the reproducing operation, the target hologram recorded in the second storage medium is generated by reflecting the horizontally polarized beam incident from the first shutter into the second storage medium by reflecting it to the reproduction reference light having a predetermined deflection angle. A reproduction path for reproducing data; Optical output selecting means for selecting an output of reproduction hologram data reproduced in the first storage medium and provided through the opening of the second shutter or reproduction data reproduced in the second storage medium in a reproduction operation; And A complex volume holographic digital storage and reproducing system comprising a CCD for converting regenerated hologram data selected and output from said light output selecting means into an electrical signal during a reproducing operation. The method of claim 1, The system further comprises a shielding film positioned between the first storage medium and the second storage medium to block optical interference between the respective media. The method according to claim 1 or 2, The recording and playback path is: An optical splitter for splitting the incident vertically polarized beam into a reference light for recording or reproduction and an object light; A third shutter for selectively opening and closing the output of the branched recording or reproduction reference light corresponding to the setting mode of the system; A first reflecting mirror reflecting the branched recording or reproducing reference light at a predetermined deflection angle to enter the first storage medium; A fourth shutter for selectively opening and closing the output of the branched object light corresponding to the setting mode of the system; A second reflecting mirror which reflects the branched object light provided through the opening of the fourth shutter at a predetermined angle during a recording operation; And The reflected object light is modulated by the external input data to generate the signal light modulated by one page unit, and the generated signal light is synchronized with the recording reference light incident on the first storage medium. A composite volume holographic digital storage and playback system comprising a spatial light separator which is incident on a beam. The method according to claim 1 or 2, The playback path is: A lens constituting a waste of the horizontally polarized beam incident from the first shutter; A beam expander for extending the horizontal polarization beam transmitted through the lens to a predetermined size; And And a third reflector reflecting the extended horizontal polarization bin to the second storage medium as a reference light for reproduction having a predetermined deflection angle.

Images