KR20070117744A - Data recording media - Google Patents

Abstract

A data recording medium is provided to enable the focusing and tracking servo drive, and to display a data storing address by forming grooves and lands on both surfaces of reflection layers. A data recording medium comprises first and second recording layers(110,120), and a reflection layer(130). Data is recorded in the first and the second recording layers by the interference between reference and signal beams. The reflection layer is formed between the first and the second recording layers to reflect the reference and the signal beams passing through the first and the second recording layers. Glass covers(111,121) are formed at both sides of the first and the second recording layers. Grooves and lands are formed on both surfaces of the reflection layer at predetermined intervals.

Description

Data recording media

1 is a block diagram schematically showing a data recording and reproducing apparatus of a first embodiment according to the present invention;

FIG. 2 is a diagram schematically showing the structure of a data recording medium of a first embodiment according to the present invention; FIG.

Fig. 3 is a diagram explaining that data is recorded on the data recording medium of the first embodiment according to the present invention.

4 is a diagram for explaining reproduction of data stored in a data recording medium of a first embodiment according to the present invention;

Fig. 5 is a configuration diagram schematically showing a data recording and reproducing apparatus of a second embodiment according to the present invention.

FIG. 6 is a diagram schematically showing the structure of a data recording medium of a second embodiment according to the present invention; FIG.

The present invention relates to a data recording medium.

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 a large amount of data inside a small recording medium.

In the conventional recording medium used in such a hologram storage device, since the layer on which the hologram data is recorded is composed of one layer, there is a problem that the capacity of the hologram data stored in one recording medium cannot be increased by more than a predetermined capacity. .

The present invention provides a recording medium capable of increasing storage capacity in a data recording and reproducing apparatus capable of recording and reproducing a large amount of data.

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 configuration diagram schematically showing a data recording and reproducing apparatus according to the present invention.

Referring to FIG. 1, a data recording or reproducing apparatus according to the present invention includes a shutter 20 for blocking or passing a beam generated by a light source 10, and a beam incident from the shutter 20 to a signal beam and a reference beam. A beam splitter 30 which is separated into a signal, a processing path S1 of the signal beam, a processing path S2 of the reference beam, and hologram data generated by interference between the signal beam and the reference beam (that is, an interference pattern Recording medium 100 is recorded.

In detail, the light source 10 may be a laser diode emitting a beam having a wavelength of 405 nm or 532 nm, and the beam splitter 30 transmits the beam by reflecting the incident beam according to the polarization direction. A polarization beam splitter (PBS) for separating may be used.

In addition, the shutter 20 performs an on / off operation so that the beam emitted from the light source 10 may be intermittently passed. At this time, the progress of the beam may be controlled by controlling the light source 10 on / off without providing the shutter 20. Then, the data recording and reproducing apparatus according to the present invention can be stored or reproduced in units of pages during data recording and reproducing.

In addition, the signal beam processing path S1 includes a spatial light modulator (SLM) 50 for loading input data to be recorded in the signal beam separated from the beam splitter 30, and the spatial light modulator. And a splitter 60 for passing the signal beam output from 50 and an objective lens (not shown) for focusing the signal beam passing through the splitter 60 and entering the recording medium 100.

In detail, the spatial light modulator 50 may be formed of a liquid crystal on silicon (LCoS) panel, and may include input data, that is, data stored in units of pages, in the signal beam passing through the beam separator 30. give. The signal beam, into which the data is input, passes through the splitter 60 and is focused by the objective lens (not shown) to be incident on the recording medium 100. Preferably, a driving device for driving the objective lens (not shown) may be further included.

Therefore, the signal beam processing path S1 serves to provide the recording medium 40 with a signal beam required for recording hologram data.

In addition, the processing path S2 of the reference beam includes an actuator 40 for changing the traveling angle of the reference beam separated from the beam splitter 30. Then, the incident position or angle of incidence of the reference beam incident on the recording medium 100 may be changed by the actuator 40.

Accordingly, the reference beam processing path S2 functions to provide the recording medium 100 with a recording or reproducing reference beam required for recording or reproducing hologram data.

In addition, the recording medium 40 is located on an optical path where the signal beam incident from the spatial light modulator 50 and the reference beam incident from the actuator 40 cross each other, and the signal beam and the reference beam The interference fringe generated by the interference is recorded, and the interference fringe recorded by the incident of the reference beam is restored.

In addition, in the data recording and reproducing apparatus according to the present invention, an image for reproducing data from a reference beam (hereinafter referred to as a reproducing beam) including data recorded on the recording medium 100 by being incident on an interference fringe of the recording medium 100. The sensor 70 is included.

In detail, the reproduction beam is reflected from the recording medium 100 to reverse the signal beam processing path S1. In addition, the splitter 60 reflects the reproduction beam to the image sensor 70, and the image sensor 70 restores the reproduction beam reflected by the splitter 60 and converts the reproduction beam into an original electric signal.

Therefore, the data recorded on the recording medium 100 can be restored by converting the original electrical signal by the image sensor 70. Here, the splitter 60 passes a signal beam for recording data on the recording medium 100 and reflects the reproduction beam reflected from the recording medium 100.

Next, the operation of the data recording and reproducing apparatus according to the present invention configured as described above will be described.

First, the laser beam generated by the light source 10 passes through the shutter 20 and is separated into a reference beam and a signal beam by the beam splitter 30.

In addition, the signal beam separated by the beam splitter 30 is incident to the spatial light modulator 50, and after passing the splitter 60 after the data to be recorded is recorded to the objective lens (not shown). It is focused by the incident to the storage medium 100.

In addition, the reference beam separated by the beam splitter 30 is changed into a predetermined position and angle by the actuator 40 and is incident to the recording medium 100.

Then, the signal beam and the reference beam cause interference in the recording medium 100, and the interference fringes generated at this time are recorded on the recording medium 100.

In addition, only a reference beam may be incident on the recording medium 100 to reproduce data recorded on the recording medium 100. Here, the reference beam incident on the recording medium 100 during reproduction should be incident at the same position and angle as the reference beam incident upon recording, which may be adjusted by the actuator 40.

When a reference beam having the same position and angle as the reference beam at the time of recording is incident on the recording medium 100, the data recorded on the recording medium 100 is included in the reference beam.

Then, the reference beam including data, that is, the reproduction beam, is reflected from the recording medium 100 to move the signal beam processing path S1 in reverse, and is reflected by the splitter 60 to reflect the image sensor 70. By being incident on, the original recorded data can be reproduced.

2 is a view for explaining the structure of the data recording medium of the first embodiment according to the present invention.

Referring to FIG. 2, the recording medium 100 according to the present invention includes first and second recording layers 110 and 120 in which interference fringes of a signal beam and a reference beam, that is, data are recorded, and the first and second recording layers 110.120. And a reflection surface 130 reflecting the signal beam and the reference beam. Glass covers 111 and 121 are formed on both sides of each of the first and second recording layers 110 and 120.

In detail, the first and second recording layers 110 and 120 may be formed of a photosensitive material such as a polymer, and the reflective surface 130 may be formed of aluminum to reflect the signal beam and the reference beam. Can be. The glass covers 111 and 121 may prevent breakage of the first and second recording layers 110 and 120 or distinguish the first and second recording layers 110 and 120 from the reflective surface 130.

Therefore, since the recording medium 100 according to the present invention has two recording layers in which data is recorded, the data storage capacity of the recording medium 100 can be doubled.

Hereinafter, with reference to FIGS. 3 and 4, data is recorded and reproduced on the recording medium 100.

3 is a view for explaining that data is recorded on a data recording medium according to the present invention.

As described with reference to FIG. 1, the reference beam 101 incident from the actuator 40 and the signal beam 102 focused by the objective lens 80 are formed on one side of the recording medium 100. 1 is incident on the recording layer 110.

Then, an interference pattern 103 is formed on the first recording layer 110 by the signal beam 102 and the reference beam 101 being incident and interfered with each other. Data included in the signal beam 102 is stored in the recording medium 100.

Meanwhile, the signal beam 102 and the reference beam 101 forming the interference pattern 103 are reflected by the reflective surface 130. Therefore, the second recording layer 120 formed on the opposite side of the first recording layer 110 with respect to the reflective surface 103 is not affected by the signal beam 102 and the reference beam.

In addition, in order to store the data in the second recording layer 120, the user takes the recording medium 100 from the data recording and reproducing apparatus and rests it on the opposite side, so that a new signal beam and a reference beam are stored in the second recording layer ( 120 may cause interference. Then, new data may be recorded in the second recording layer 120 by the new signal beam and the reference beam.

Even in this case, the signal beams and the reference beams having the interference pattern formed on the second recording layer 120 are reflected by the reflecting surface 130, thereby having no effect on the data recorded on the first recording layer 110. Does not have

As such, since the data recording medium 100 according to the present invention can store new data in the first and second recording layers 110 and 120 without affecting each other, the conventional recording in which only one recording layer exists. Twice as much data as the media can be stored, thus doubling the storage capacity.

4 is a view for explaining the reproduction of data stored in a data recording medium according to the present invention.

The reference beam 101 is generated and proceeds as described with reference to FIGS. 1 and 3, and is incident on the recording medium 100 in the direction as shown in FIG. 4.

In order to reproduce data from the interference pattern 103 formed on the first recording layer 110, the reference beam 101 is incident in the same direction as the incident direction when the interference pattern 103 is formed.

The reference beam 101 passing through the interference pattern 103 is reflected by the reflecting surface 130 and is incident to the objective lens 80. In this case, the reference beam 101 is converted into a reproduction beam 104 including data recorded in the first recording layer 110.

In addition, the reproduction beam 104 incident to the objective lens 80 reverses the movement path of the signal beam, is reflected by the splitter 60, and is incident to the image sensor 70. Then, the image sensor 70 detects the incident beam as an electrical signal so that the data stored in the recording medium 100 can be reproduced. Here, the image sensor 70 may be a CMOS image sensor.

Meanwhile, in order to reproduce the data recorded on the second recording layer 120, the user takes out the recording medium 100 so that a reference beam for reproducing the recorded data on the opposite second recording layer 120 is incident. In this case, the data recorded in the second recording layer 120 may be reproduced in the same manner as the data recorded in the first recording layer 110 is reproduced.

Accordingly, the recording medium 100 according to the present invention can be reproduced without mutually affecting the data recorded in the first and second recording layers 110 and 120.

5 is a configuration diagram schematically showing a data recording and reproducing apparatus of a second embodiment according to the present invention.

The data recording and reproducing apparatus according to the present embodiment differs only in that the servo beam processing path S3 is further included as compared with the first embodiment. Reference is made to the description and reference numerals in the first embodiment.

Referring to FIG. 5, in the data recording and reproducing apparatus according to the present embodiment, when the recording medium 200 is inclined by external vibration or pressure, a signal beam and a reference beam are incident on the recording medium 200. Servo beam processing path (S3) for adjusting the position and the angle is further included.

When the recording medium 200 is inclined by an external vibration or pressure, the incident position and angle of the signal beam and the reference beam incident on the recording medium 200 may be changed. Then, an error may occur when data is recorded on the recording medium 200 or when the recorded data is reproduced, which may cause problems during recording and reproduction.

Therefore, in order to keep the position and angle of the signal beam and the reference beam incident on the recording medium 200 when the recording medium 200 is inclined, it is determined how much the recording medium 200 is inclined. I need information.

To this end, the present embodiment further includes a servo beam processing path S3 for obtaining information on how inclined the recording medium 200 is.

In general, a blue beam having a wavelength of 480 nm or a green beam having a wavelength of 532 nm is used as a beam for recording and reproducing data, and a servo beam has a red beam having a wavelength of 650 nm. beam may be used. In addition, a control device (not shown) and a drive for adjusting the incidence positions and angles of the signal beam and the reference beam according to the information on the inclination of the recording medium 200 obtained by the servo beam processing path S3. A device (not shown) is further included.

In detail, the servo beam processing path S3 includes first and second splitters for passing a second light source 250 for generating a servo beam and a servo beam generated at the second light source 250 along the polarization direction. 252 and 253 and a photo detector 251 for determining the degree of inclination of the recording medium 200 from the servo beam incident and reflected on the recording medium 200.

Here, the second light source 250 may be a laser diode emitting a red beam having a wavelength of 650nm, the first light source 10 may be a laser diode emitting a green beam having a wavelength of 532nm. have.

In addition, the first splitter 252 passes the servo beam generated by the second light source 250, and the second splitter 253 reflects the servo beam passed through the first splitter 252. In this case, the splitter 60 is formed to pass the servo beam reflected by the second splitter 253.

Then, the servo beam may be focused on the objective lens 80 by moving in the same optical path as the signal beam and incident on the recording medium 200.

In addition, the servo beam is reflected from the recording medium 200, and reverses the servo beam processing path S3. Here, the servo beam reflected from the recording medium 200 includes information about how inclined the recording medium 200 is.

Then, the servo beam reflected by the recording medium 200 passes again through the splitter 60, is reflected by the second splitter 253, and is reflected by the first splitter 252 to be reflected by the light detector 251. Incident.

In addition, the light detector 251 determines whether the recording medium 200 is inclined from the servo beam incident from the first splitter 252.

In general, the light detection unit 251 may be a divided light detection sensor consisting of a four-segment photodiode or the like. For example, the light detector 251 is divided into four divided sensor areas A, B, C, D, and compares the amount of light detected in each area with the amount of light in the horizontal and vertical sensor areas, and the recording medium 200. ) To determine if it is tilted.

6 is a diagram schematically showing the structure of a data recording medium in the second embodiment according to the present invention.

The data recording medium 200 according to the second embodiment of the present invention has a dichroic mirror 240 and a reflective layer (compared with the structure of the data recording medium 100 according to the first embodiment). Since only 230 is different, other descriptions refer to the description in the first embodiment.

Referring to FIG. 6, in the data recording medium 200 according to the second embodiment, a dichroic mirror 240 is formed between the first and second glass covers 211 and 221 and the reflective layer 230, and the reflective layer 230 is formed. Grooves 231 and lands 232 are formed on both surfaces at predetermined intervals, and a spacer layer 241 is formed between the dichroic mirror 240 and the reflective layer 230. do.

In detail, the dichroic mirror 240 is formed to reflect or pass depending on the wavelength of the beam. Here, the dichroic mirror 240 is configured to reflect the blue beam of 480nm wavelength or the green beam of 532nm wavelength, and to pass the red beam of 650nm wavelength.

Then, the signal beam and the reference beam formed of the blue beam or the green beam are reflected by the dichroic mirror 240 through the first recording layer 210 or the second recording layer 220, and the servo beam formed of the red beam. May pass through the dichroic mirror 240.

In addition, both surfaces of the reflective layer 230, that is, the surface on which the groove 231 and the land 232 are formed, are formed of aluminum so that the servo beam passing through the dichroic mirror 240 is reflected. Then, the servo beam passing through the dichroic mirror 240 is reflected on the surface of the reflective layer 230 to move the servo beam processing path S3 in reverse.

In addition, the groove 231 is formed to be recessed with respect to the surface of the reflective layer 230, and the land 232 is formed to protrude relative to the groove 231. The groove 231 and the land 232 may be formed in a spiral shape from the inside of the recording medium 200 to the outside in accordance with the rotation of the recording medium 200.

Further, the pitch of the grooves 231 and the lands 232 may be formed to be longer or shorter than the wavelength of the servo beam, or may be formed to be long and short.

Then, the servo beam reflected from the surface of the reflective layer 230 may include information on the inclination of the recording medium 200 when the recording medium 200 is inclined by an external vibration or pressure, the recording medium 200 Information about the address of the data recorded in may be included.

As a result, the servo beam passing through the dichroic mirror 240 is reflected on the surface of the reflective layer 230, thereby enabling focusing and tracking servo driving of the recording medium 200. Since the address of the data recorded on the recording medium 200 can be known, the data to be played back can be easily found during playback.

In the present embodiment, like the first embodiment, the first and second recording layers 210 and 220 are formed, and the signal beams and the reference beams for data recording and reproduction are reflected by the dichroic mirror 240. Since the servo beam is reflected on the surface of the reflective layer 230, each of the first and second recording layers 210 and 220 does not affect each other and data may be recorded or reproduced.

Therefore, in the present exemplary embodiment, the information on the degree of inclination of the recording medium 200 and the storage address of the data may be displayed, but the recording layer on which the data is recorded may be doubled. However, in the present embodiment, the intervals or shapes of the grooves 231 and the lands 232 are the same on both surfaces of the reflective layer 230, but differently to suit the first and second recording layers 210 and 220. It may be formed.

In the data recording medium according to an embodiment of the present invention, the data capacity of one data recording medium can be doubled by forming two layers in which data is recorded.

In addition, in the data recording medium according to the embodiment of the present invention, grooves and lands are formed in the reflective layer to enable focusing and tracking servo driving, and to indicate an address where data is stored.

Claims (8)

First and second recording layers on which data is recorded due to interference between the reference beam and the signal beam; And a reflective surface formed between the first recording layer and the second recording layer to reflect a reference beam and a signal beam past the first recording layer or the second recording layer. The method of claim 1, And a glass cover is formed on both sides of the first and second recording layers. The method of claim 1, And the reflective surface is made of aluminum. The method of claim 1, And the recording layer is made of a polymer. First and second recording layers in which interference fringes of the reference beam and the signal beam are recorded; A dichroic mirror which reflects the reference beam and the signal beam passing through the first recording layer or the second recording layer and passes the servo beam; And And a reflecting surface for reflecting the servo beam passing through the dichroic mirror. The method of claim 5, Grooves and lands are formed on both surfaces of the reflective surface at predetermined intervals. The method of claim 6, And the pitch of the grooves and lands is formed longer or shorter than the wavelength of the servo beam. The method of claim 5, The dichroic mirror is configured to reflect the green beam or the blue beam, and to pass the red beam.

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