KR20080040144A - Recording and playback device and method - Google Patents

Abstract

According to an embodiment of the present invention, a recording and reproducing apparatus includes: a beam separator for separating a beam incident from a light source into a reference beam and a signal beam; A spatial light modulator for modulating data to be recorded in the signal beam; A first Fourier lens for Fourier transforming the signal beam or reference beam; A spatial filter for intermittent movement of a Fourier transformed beam by the first Fourier lens; And a second Fourier lens for inverse Fourier transforming the beam passing through the spatial filter.

Description

Apparatus and method for recording / reproducing

1 is a diagram for explaining a recording and / or reproducing apparatus according to an embodiment of the present invention;

2 shows a spatial filter according to an embodiment of the invention.

3 to 10 are diagrams for explaining a method of recording data and a method of reproducing recorded data according to an embodiment of the present invention.

The present invention discloses an apparatus for recording data or reproducing recorded data.

Representative examples of recording media on which data is recorded include CD (Compact Disc) and DVD (Digital Versatile Disc). CDs and DVDs are recording media that store data using spots of beams emitted from a laser light source.

CD or DVD uses a method of increasing the storage capacity by adjusting the pitch interval or increasing the recording layer, but due to physical limitations, it is no longer possible to increase the storage capacity.

Meanwhile, with the development of multimedia technology, there is a demand for a recording medium capable of storing more data, a data recording device capable of storing data on such a recording medium, and a data reproducing apparatus capable of reproducing the recording medium.

Accordingly, in recent years, research on data recording and reproducing apparatus using holograms has been actively conducted.

The data recording and reproducing apparatus using the hologram records and reproduces information in a storage medium using diffraction and interference effects of light, and is generally generated by interference between a signal beam and a reference beam. Use an interference fringe.

That is, when a signal beam and a reference beam are irradiated on a recording medium, an interference fringe is formed by the interference between the signal beam and the reference beam, and the interference fringe (i.e., hologram data) thus formed is stored. Recorded on the medium. When the reference beam is irradiated to the storage medium storing the interference fringe, the interference fringe stored in the storage medium is reproduced, and the recorded data is reproduced.

At this time, the hologram data recorded on the recording medium can be read only by the reference beam used in the recording process, and cannot be read by the reference beam having a different wavelength or phase from the reference beam used at the time of recording, Pass the hologram data.

By using this hologram property, a large amount of hologram data is recorded in the same place on the recording medium with different reference beams, thereby making it possible to store massive data inside a small recording medium.

In such a hologram storage device, data is recorded in a plurality of page units, and the pages are recorded so as not to overlap each other. Also, even when the book is to be reproduced, the reproduction of data does not occur correctly when the books overlap each other.

In view of this, in the conventional recording and / or reproducing apparatus, there is a limitation in that the capacity of data cannot be increased by a certain amount or more.

In order to solve the conventional problems as described above, a recording and / or reproducing apparatus capable of increasing the capacity of data that can be recorded on a recording medium is proposed.

According to an aspect of the present invention, a recording and reproducing apparatus includes: a beam separator for separating a beam incident from a light source into a reference beam and a signal beam; A spatial light modulator for modulating data to be recorded in the signal beam; A first Fourier lens for Fourier transforming the signal beam or reference beam; A spatial filter for intermittent movement of a Fourier transformed beam by the first Fourier lens; And a second Fourier lens for inverse Fourier transforming the beam passing through the spatial filter.

According to an embodiment of the present invention, a recording and reproducing method includes: recording a first data page on a recording medium by interfering a spatial light modulated signal beam with a reference beam; And recording the second data page by using the signal beam and the reference beam after moving the recording medium in a first direction, wherein the recording of the signal beam or reference beam is performed when the first data page is recorded. The Fourier transformed beam passes through a spatial filter for intermittent beams, and the Fourier transformed beams of the signal beam or reference beam are interrupted by the spatial filter when the second data page is written.

Hereinafter, exemplary embodiments of the inventive concept will be described in detail with reference to the accompanying drawings. However, the spirit of the present invention is not limited to the appended embodiments, and those skilled in the art who understand the spirit of the present invention can easily add, change, delete, and add other embodiments included in the scope of the same idea. I would be able to suggest.

1 is a view for explaining a recording and / or playback apparatus according to an embodiment of the present invention, Figure 2 is a view showing a spatial filter according to an embodiment of the present invention.

In the recording and / or reproducing apparatus according to the present invention, a spatial filter 230 is provided to increase the recording capacity of the data, and the spatial filter 230 has a shape corresponding to the format of the data page used.

The beam for passing through the spatial filter 230 is Fourier transformed by the first Fourier lens 221, and the beam passing through the spatial filter 230 is passed through the second Fourier lens before reaching the image sensor 240. 222) is inverse Fourier transformed.

In the spatial filter 230, holes 231 having a predetermined size are formed at predetermined intervals according to a format of a data page used to pass a Fourier transformed beam by the first Fourier lens 221.

After predetermined data is recorded on the recording medium 200 as a first page, the recording medium 200 is shifted several to several tens of micrometers, and another data is recorded as the second page. Here, predetermined portions of the first page and the second page on which different data are recorded may overlap.

Here, according to the related art, although it is impossible to separately reproduce the overlapped pages, according to an embodiment of the present invention, the control unit (not shown) stores the moving distance of the recording medium 200 when data is recorded. In this case, the recording medium 200 is reversely moved using the moving distance stored during data reproduction. Here, the movement of the recording medium 200 may vary depending on the configuration of the apparatus supporting the recording medium 200, but may be performed by the movement of the pickup base, but is not necessarily limited to this configuration.

When the data is reproduced, the overlapped pages may be distinguished using the spatial filter 230.

Hereinafter, the recording and / or reproducing apparatus of the present invention will be described in more detail.

First, referring to FIG. 1, the recording and / or reproducing apparatus according to the present invention separates a shutter 120 for blocking or passing a beam emitted from a light source 110 and a beam incident from the shutter 120. The first beam splitter 130 is provided.

For example, the light source 110 may be a laser diode that emits a beam of wavelength 405nm or 532nm, the first beam splitter 130 transmits or reflects the beam according to the polarization direction of the incident beam Polarization Beam Splitter (PBS) for splitting beams may be used.

The beam incident to the first beam splitter 130 is divided into a reference beam and a signal beam.

The shutter 120 performs an on / off operation so that the beam emitted from the light source 110 may be intermittently passed. At this time, the progress of the beam may be controlled by controlling the light source 110 on / off without the shutter 1200.

The configuration of the device formed on the movement path of the signal beam and the reference beam separated by the first beam splitter 130 will be described.

The signal beam (first beam) passing through the first beam splitter 130 is reflected by the first reflection mirror 140 and expanded by the beam expander 150.

The signal beam passing through the beam expander 150 is reflected by the second beam splitter 160 and then incident to the spatial light modulator (SLM) 170.

The spatial light modulator 170 may be formed of a liquid crystal on silicon (LCoS) panel, and the signal beam is reflected from the spatial light modulator 170 and modulated. Therefore, data to be recorded is included in the signal beam.

The signal beam reflected by the spatial light modulator 170 and then incident to the second beam splitter 160 includes data to be recorded, and the signal beam passes through the second beam splitter 160 and then It is incident on the objective lens 180.

The signal beam incident on the objective lens 180 is focused and then incident on the recording area on the recording medium 200.

Meanwhile, the reference beam (second beam) reflected by the first beam splitter 130 is reflected by the second reflection mirror 190 and then enters the recording area of the recording medium 200.

The signal beam and the reference beam interfere with each other in the recording area of the recording medium 200 to form an interference pattern.

When the data recorded in the interference pattern is to be reproduced, the data pattern is observed through the image sensor 240 when the reference beam is incident on the recording medium 200.

A method of recording data and a method of reproducing recorded data according to an embodiment of the present invention will be described with reference to FIGS. 3 to 10.

First, when reproducing data recorded on the recording medium 200, a reproduction method using the reference beam will be described.

The data page in the case of reproducing the data recorded on the recording medium 200 has a form as shown in FIG. The data page having this shape becomes a Fourier transformed beam having a shape as shown in FIG. 4 while passing through the first Fourier lens 221.

A collimator lens 210 may be further formed between the recording medium 200 and the first Fourier lens 221 to convert parallel light.

The Fourier transformed beam through the first Fourier lens 221 passes through the hole 231 formed in the spatial filter 230 while passing through the spatial filter 230 as shown in FIG. 5. Here, the shape and position of the hole 231 formed in the spatial filter 230 may be variously changed according to the data format used in the recording and / or reproducing apparatus of the present invention as described above. to be. That is, it is possible to filter by placing a spatial filter according to the characteristics and shape of the SLM.

The Fourier transformed beam passing through the spatial filter 230 is Fourier inversely transformed by the second Fourier lens 222, and the Fourier inversed beam is transformed by the image sensor 240 as shown in FIG. Is observed.

3 to 6 illustrate a case in which a Fourier transformed beam may pass through the spatial filter 230 among the data pages recorded on the recording medium 200. In this case, the recording may be performed. When the medium 200 is moved a predetermined distance (for example, several tens of micrometers), the Fourier transformed beam cannot pass through the hole 231 formed in the spatial filter 230.

According to the present invention, even when a plurality of data pages are recorded overlapping on the recording medium 200, the present invention can reproduce them separately.

A schematic diagram when the Fourier transformed beam by the first Fourier lens 221 passes through the spatial filter 230 is briefly shown in FIG. 7.

When the recorded first data page is reproduced, it is assumed that a Fourier transformed beam of the first data page passes through the spatial filter 230, as shown in FIG. A method of recording a second data page recorded so that predetermined areas overlap.

First, in recording the second data page, when the recording medium 200 is moved a predetermined distance in a specific direction and data is recorded, the beam 300 converted by the first Fourier lens 221 is As shown in FIG. 8, the hole 231 of the spatial filter 230 may not penetrate.

For example, in the case of recording data after moving the recording medium 200 to several tens of micrometers in a predetermined direction in recording the second data page, the Fourier transformed beam 300 of the second data page is The image may not penetrate the spatial filter 230, and thus the image observed through the image sensor 240 may change from the photograph shown in FIG. 6 to the photograph shown in FIG. 9.

In this manner, when the recording medium 200 is further moved in a predetermined direction in recording another third data page, a Fourier transformed beam is transmitted to the spatial filter 230 as shown in FIG. 5 or 7. ) Will be transmitted.

In recording data (or data page) on the recording medium 230, the recording medium 200 is moved a predetermined distance in a predetermined direction, and the movement of the recording medium 200 is Fourier transformed on the data page to be recorded. After the beam has passed through the spatial filter 230, a distance that does not pass through the spatial filter 230 is performed.

That is, the controller of the recording and / or reproducing apparatus stores the shape of the spatial filter 230, that is, the size of the hole 231 and distance information between the holes. The controller may allow the data page to be recorded so that a Fourier transformed beam of the first data page may pass through the spatial filter 230, and the second data page may overlap the first data page. The recording medium 200 is moved to a size smaller than the distance between the holes of the spatial filter 230.

In this case, the control unit stores the distance traveled by the recording medium 200 and records the recording medium 200 using the moving distance information of the recording medium 200 when the second data page is reproduced. Move in the reverse direction to the moving direction.

Accordingly, the Fourier transformed beam of the second data page is moved to a position through which the spatial filter 230 can pass, from which the image sensor 240 can detect the second data page. .

The recording method and the reproduction method by this method will be described in more detail with reference to FIG.

10 is a diagram for explaining a recording and / or reproducing method according to an embodiment of the present invention.

FIG. 10 shows two diagrams that can be distinguished according to whether or not the recording medium 200 is moved. Through the above diagram, the first data is irradiated with a signal beam and a reference beam. You can assume that you are writing a page.

In the following figure, it is assumed that the second data page is recorded by using the interference between the signal beam and the reference beam when the recording medium 200 is moved by W in the x + direction (the first direction). Can be.

In this case, the areas of the first data page and the second data page overlap each other, where the distance W moved by the recording medium 200 may be several to several tens of micrometers. It may be moved smaller than the distance between the holes 231 formed in the spatial filter 230.

When the second data page is recorded by moving the recording medium 200 by W in the x + direction, the recording medium 200 is moved in the x-direction when the second data page is reproduced. After moving by so that the reference beam can be irradiated.

That is, the control unit of the recording and / or reproducing apparatus according to the present invention stores the distance W moved by the recording medium 200 when recording the second data page and then reproduces the second data page. The recording medium 200 is moved in the reverse direction by the distance W and then played back.

In this case, when the recording medium 200 is moved by the distance W to record the second data page, a Fourier transformed beam cannot pass through the spatial filter 230 and is observed through the image sensor 240. The interference pattern is as shown in FIG.

In addition, when the recording medium 200 is moved in the opposite direction by the distance W to reproduce the second data page, a Fourier transformed beam may pass through the spatial filter 2300, and the image sensor 240 may be moved. The interference pattern observed through may be similar to the photograph shown in FIG. 6.

According to the embodiment of the present invention as described above, it is possible to record so that pages which are units of data recording on the recording medium overlap each other, and furthermore, the reproduction of the overlapped data pages is possible.

As a result, there is an advantage that the recording capacity of the data can be increased.

The recording and / or reproducing apparatus as proposed has the advantage of greatly improving the recording capacity of the data.

Claims (7)

A beam splitter separating the beam incident from the light source into a reference beam and a signal beam; A spatial light modulator for modulating data to be recorded in the signal beam; A first Fourier lens for Fourier transforming the signal beam or reference beam; A spatial filter for intermittent movement of a Fourier transformed beam by the first Fourier lens; And And a second Fourier lens for inverse Fourier transforming the beam passing through the spatial filter. The method of claim 1, And a hole through which the Fourier transformed beam passes through the spatial filter according to a data format recorded on the recording medium. The method of claim 1, A control unit for performing recording or reproducing of the recording medium is further included. The controller controls to move the recording medium in a predetermined direction when data is recorded on the recording medium, and controls to move the recording medium in the opposite direction to the moved direction when the data is reproduced. Device. The method of claim 1, And an image sensor for receiving the inverse Fourier transformed beam by the second Fourier lens. Writing a first data page to a record carrier by interfering with the spatial light modulated signal beam and the reference beam; And And recording the second data page using the signal beam and the reference beam after moving the recording medium in a first direction. When the first data page is written, a Fourier transformed beam of the signal beam or the reference beam passes through a spatial filter for controlling the beam. And the Fourier transformed beam of the signal beam or the reference beam is interrupted by the spatial filter during the recording of the second data page. The method of claim 5, wherein And upon reproducing the second data page, the recording medium is moved in a second direction opposite to the first direction. The method of claim 5, wherein And recording data such that the first data page and the second data page overlap a predetermined area.

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