KR20080062360A - Hologram recording apparatus and method - Google Patents

Abstract

A hologram recording apparatus and a hologram recording method are provided to record track information by causing reference beam, signal beam, and control beam of recording data information to interfere with the hologram medium so as to drive an actuator by using the accurate track information, and to detect position, tilt angle and track interval of the hologram medium by using a PD array whose response speed is fast. A hologram recording apparatus comprises light sources(104,105,106), a first light receiving device(109), a second light receiving device(110), and an actuator. The light sources generate reference beam, signal beam of recording data information, and control beam of recording track information. The first light receiving device receives the reference beam of irradiating the former track and generates the information for track interval control. The second light receiving device receives the control beam and generates current state information. The actuator adjusts position and tilt angle of the hologram medium based on the information from the first light receiving device.

Description

Hologram recording apparatus and method

1A and 1B show a data recording operation of a hologram recording apparatus according to an embodiment of the present invention.

Fig. 2 shows the state of the hologram medium when recording data on the nth track during recording of the hologram recording device according to the present invention.

3 shows the configuration of a hologram recording device according to another embodiment of the present invention.

4 shows a hologram reproducing apparatus according to an embodiment of the present invention.

5 shows a multi-divided PD array that can be used as a light receiving element in the present invention.

※ Description of main part of drawing ※

101,318: signal beam 102,312: reference beam

103,313: control beam 104,105,106,301,401: light source

107,314,414: hologram medium 108, 112: recording spot

109,316: first light receiving element 110,315,416: second light receiving element

304, 404: polarization beam splitter 303,305,403,405: polarization element

The present invention relates to a data recording apparatus and method of a holographic medium.

More specifically, in the storage device using a hologram as a mass storage device, a control beam is additionally generated in addition to the reference beam and the signal beam, and the track information is generated during reproduction and recording of the hologram medium using the track, and the track A hologram capable of controlling the interval and correcting the tilt relates to a data recording apparatus and method.

A hologram storage device modulates two-dimensional data using a SLM (Spatial Light Modulator) to generate a signal beam, and records the data by interfering with the reference beam in a storage medium.

When the reference beam is projected onto the hologram storage medium under the same conditions as in writing, a diffracted signal beam is generated, and data is obtained by using a CCD or a CMOS as a data readout device.

In the conventional optical storage device, since the wobble (track information) pattern is pre-formed on the media itself, the speed, position, tracking, and focusing can be achieved through a three-beam method (CD) or a one-beam method (DVD) based on a phase difference method. I'm in control.

However, since the hologram recording medium is transparent when the recording method is recorded on the hologram storage medium, it is difficult to control the wobble signal on the medium in the pre-format.

In addition, it is not suitable as a storage device for finding an accurate position by using a CCD or CMOS, which has a slow response time, using a data reading device when the hologram storage medium is reproduced. To this end, the approach of dividing and extracting a part of the beam by a beam splitter, etc. and processing it into a PD array has been introduced in the prior art, but there is a disadvantage in terms of efficiency.

In addition, in order for a hologram storage device to be commercially available, data must be recorded on a actually rotating medium, and at the same time, the data can be read at an accurate position. In other words, track information should be recorded at intervals that minimize crosstalk with adjacent tracks on a medium, and a technique for accurately following the tracks is required.

According to the present invention, when recording data through interference of a reference beam and a signal beam on a hologram medium, the control beam having the same polarization state as that of the reference beam is interfered together, thereby accurately detecting the position, tilt angle and track interval of the hologram medium during recording and playback. It is an object of the present invention to provide a hologram recording apparatus and method capable of driving an actuator.

In addition, the present invention provides a hologram recording apparatus and method capable of driving an actuator using accurate track information during reproduction by recording track information together by interfering a control beam in addition to the reference beam and the signal beam on the hologram medium. The purpose.

It is also an object of the present invention to provide a hologram recording apparatus and method capable of detecting the position, tilt angle and track interval of a hologram medium using a PD array with a fast response speed as a light receiving element for receiving a control beam.

According to an embodiment of the present invention, a hologram recording apparatus includes: a light source unit generating a reference beam, a signal beam interfering with the reference beam to record data information, and a control beam interfering with the reference beam to record track information; A first light receiving element that receives a reference beam irradiating a previous track and generates information for track interval control; And an actuator for adjusting the position and tilt of the hologram medium based on the information generated by the first light receiving element.

Hologram recording method according to an embodiment of the present invention, generating a reference beam, a signal beam and a control beam; Irradiating the reference beam, the signal beam, and the control beam to a previous track of a hologram medium to record data and track information; And recording data and track information in the current track.

According to one or more exemplary embodiments, a hologram reproducing apparatus includes: a light source unit generating a reference beam; A light receiving element receiving the reference beam passing through the track of the hologram medium to generate the hologram medium current state information; An actuator for controlling the position of the hologram medium based on the information generated by the light receiving element; And a reading element for receiving the reference beam passing through the track of the hologram medium to read information.

Hologram reproduction method according to an embodiment of the present invention, generating a reference beam; Receiving a reference beam that has passed through the track of the hologram medium to generate tilt state information of the hologram medium; Driving an actuator to compensate for the tilt of the medium based on the generated information; And receiving and reading a reference beam that has passed through the hologram medium.

A hologram storage medium according to an embodiment of the present invention includes data information recorded by interference between a reference beam and a signal beam; And track information recorded by the reference beam and the control beam interference is recorded.

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

1A and 1B show a data recording operation of a hologram recording apparatus according to an embodiment of the present invention.

1A and 1B, a hologram recording apparatus according to the present invention includes a signal beam light source 104 for generating a signal beam 101, a reference beam light source 105 for generating a reference beam 102, and a control beam ( The first light receiving element 109 that receives the control beam light source 106 for generating 103 and the control beam 103 passing through the track currently being recorded on the hologram medium 107 to generate information for controlling the interval between tracks. It is configured to include.

More preferably, to control the position and tilt of the hologram medium 107 by receiving the control beam 103 passing through the previous track in which the track information by the interference of the reference beam 102 and the control beam 103 is recorded. It includes a second light receiving element 110 for generating information for.

Fig. 1A shows an operation of recording data and track information (wobble) together on the previous track ((n-1) th track), and Fig. 1B shows data on the next track, i.e., the current track (nth track). Indicates the operation of recording track information.

In Fig. 1A, the signal beam 101, the reference beam 102 and the control beam 103 are irradiated to the previous track at the same time to form the recording spot 108. The signal beam 101 and the reference beam 102 interfere with each other to form data information. Like the reference beam 102, the control beam 103 is unmodulated light and generates track information indicating the presence and location of data by interfering with the reference beam 102. The signal beam 101 is a beam modulated according to the data information to be recorded.

The signal beam 101 and the reference beam 102, or the control beam 103 and the reference beam 102 cause interference in the hologram medium 107, and the motion inside the hologram medium depends on the intensity of the interference fringes generated. A light induction phenomenon of a mobile charge occurs and data information and track information are recorded through this process.

The second light receiving element 110 receives the control beam 102 passing through the track currently being recorded on the hologram medium 107 and checks whether the position and the tilt state of the current medium 107 are correct to display the current state information on the hologram medium ( It transmits to the actuator (not shown) which controls the position of 107, or the control part (not shown), and can control the position of the hologram medium 107 correctly. The second light receiving element 110 recognizes the position where the intensity of the control beam 103 received is the maximum as the correct position.

In Fig. 1B, the signal beam 101, the reference beam 102, and the control beam 103 are irradiated simultaneously to the next track, i.e., the nth track, to form a recording spot 112. Figs. Similarly, the signal beam 101 and the reference beam 102 interfere with each other to form data information, and the track information (wobble) is formed by the interference between the control beam 103 and the signal beam 101, and the recording spot 112 The data information and track information are recorded together in the nth track to be examined.

At the same time, the reference beam 102 is irradiated to the (n-1) th track in which the track information is recorded, and the reference beam 102 passes through the (n-1) th track of the hologram medium 107 to make the first track. The light receiving element 109 is received.

The first light receiving element 109 receives the reference beam 102 passing through the (n-1) th track and generates information on whether the track interval is correct. Using this information, an actuator (not shown) or a control unit (not shown) of the hologram recording device is driven to accurately maintain the distance between the track currently being recorded and the previous track.

Similarly, the first light receiving element 110 determines the position where the intensity of the received reference beam 102 is the maximum as a state in which the accurate track interval is maintained accurately. Even while data is recorded on the nth track of FIG. 1B, the second light receiving element 110 receives the reference beam 102 passing through the hologram medium 107 to check the current data recording state, and thereby the hologram medium 107. Should be recorded at the correct position and tilt.

A laser diode may be used as the light sources 104, 105, and 106, and a multi-divided PD array as shown in FIG. 5 may be used as the first light receiving element 109 or the second light receiving element 110. By using the multi-divided PD array as shown in FIG. 5, it is possible to detect and compensate an accurate beam roughness or media inclination through the difference in light intensity between PD elements constituting the PD when the medium 107 rotates.

Fig. 2 shows the state of the hologram medium 107 at the time of recording data on the nth track during the recording of the hologram recording device according to the present invention.

In Fig. 2, data information and track information are recorded at a position where a reference beam, a control beam, and a signal beam are irradiated simultaneously to form a recording spot 112 in the nth track, and track information of the (n-1) th track. In the recorded position 108, the reference beam spot 113 is irradiated to read the track information.

As shown in Fig. 2, the diameter of the spot formed on the hologram medium by the signal beam and the control beam for generating data information is within about 1 mm, and the diameter of the spot 113 generated by the reference beam is about 5 mm. to be. The track spacing is about 1 mm.

Therefore, since the diameter of the reference beam is larger than the track interval, it is irradiated to cover two tracks. In the nth track where data recording is performed, data information and track information are recorded by interfering with the signal beam and the control beam, and (n In the first track, track information can be read.

3 shows the configuration of a hologram recording device according to another embodiment of the present invention.

In the embodiment shown in Fig. 3, without polarizing the light source of the reference beam and the control beam, polarized light from one light source is polarized and used as the reference beam and the control beam, respectively.

As shown in Fig. 3, the hologram recording apparatus according to the present invention includes a signal beam light source 310 for generating a signal beam 318, a light source 301 for generating a reference beam 312 and a control beam 313. And a first light receiving element 316 for receiving the reference beam 312 passing through the previous track of the hologram medium 314 to generate information for adjusting the track interval.

More preferably, receiving the control beam 313 passing through the previous track in which the track information by the interference of the reference beam 312 and the control beam 313 is recorded to control the position and tilt of the hologram medium 107 It includes a second light receiving element 315 for generating information for.

For example, the vertical light (S wave) generated by the light source 301 passes through the first polarizing element 302 and becomes, for example, light in which vertical light (S wave) and horizontal wave (P wave) are mixed. The middle vertical light is reflected by the polarization beam splitter 304 and directed to the lens 307, and the horizontal wave passes through the beam splitter 304.

According to an embodiment, the light source 301 may further include a collimated lens 302 that makes the light generated by the parallel light.

The vertical light reflected by the beam splitter 304 is used as the control beam 313, and the horizontal light transmitted through the beam splitter 304 becomes vertical light while passing through the second polarizing element 305 again. Is used as the reference beam 312. As a result, the control beam 313 and the reference beam 312 have the same polarization state.

According to the exemplary embodiment, the reference beam 312 and the control beam may be adjusted by adjusting an angle of polarized light by the first polarization element 303, thereby adjusting a ratio of vertical light and horizontal light of light passing through the first polarization element 303. The intensity of 313 can be adjusted. For example, when the polarization of the light is rotated by 45 degrees by the first polarization element 303, the ratio of the reference beam 312 and the control beam 313 is 1: 1. At this time, the polarization state of the signal beam 318 generated by the light source 310 should also be vertical light. The signal beam 318 is focused by the focusing lens 311 and is irradiated to the hologram medium 314.

In addition, the recording operation is the same as the recording apparatus shown in Figs. 1B and 1B.

4 shows a hologram reproducing apparatus according to an embodiment of the present invention.

The hologram reproducing apparatus according to the present invention shown in FIG. 4 receives a light source 401 for generating a reference beam and a reference beam passing through a track of the hologram medium 414 to generate the hologram medium current state information. 416, an actuator (not shown) for controlling the position of the hologram medium 416 based on the information generated by the light receiving element 416, and receiving a reference beam passing through the track of the hologram medium 416. It consists of a reading element 417 for reading information.

As the reading element 416, a CMOS or CCD camera can be used.

According to the exemplary embodiment, the collimating lens 402 which makes the light generated by the light source 401, for example, the vertical light into the parallel light, and the first polarizing element 403 that polarizes the light into the mixed light of the vertical light and the horizontal light ), A polarizing beam splitter 404 for transmitting only horizontal light among the light passing through the first polarizing element 403, and a second polarizing element for making the light passing through the polarizing beam splitter 404 into vertical light to make the reference light ( 406).

In addition, the hologram reproducing apparatus according to the present invention may include mirrors 406 and 408 which reflect the reference light passing through the second polarizing element 406 and irradiate the hologram medium 414.

In addition, the light passing through the hologram medium 414 may include a collimated lens 411 that makes the parallel light, or focuses and irradiates the reading element 417.

The hologram recording apparatus according to the present invention shown in Figs. 1A, 1B or 3 can also be used as a playback apparatus by mounting only the reading element 417. Figs. However, the control beam and the signal beam are not used during the reproduction operation.

As the light receiving element 416, a multi-divided PD array as shown in FIG. 5 may be used. When the hologram medium 414 is rotated, a tracking error can be compensated for by the difference in the light intensity of the beams detected by each PD element constituting the PD array, and when the difference value is generated, the tracking error can be detected to compensate for the media tilt.

If the current position or tilt of the hologram medium 414 is detected using the PD array, accurate tracking and tilt compensation is possible through the PD array with high sensitivity and response speed rather than finding the exact position with a slow response CCD or CMOS. It can provide accurate data acquisition and trigger source.

According to the hologram recording apparatus and method of the present invention, by recording track information on a hologram medium, it can also be used for tracking, media tilt and focus compensation during recording and playback.

According to the hologram recording apparatus and method of the present invention, hologram media recording and reproducing can be performed more accurately and efficiently by grasping the state of the hologram medium using a PD array having a faster response speed than CCD or CMOS at the time of data reproduction.

According to the hologram recording apparatus and method of the present invention, data and track information can be recorded while maintaining the same interval.

Claims (15)

A light source unit generating a reference beam, a signal beam interfering with the reference beam to record data information, and a control beam interfering with the reference beam to record track information; A first light receiving element that receives a reference beam irradiating a previous track and generates information for track interval control; And An actuator for adjusting the position and tilt of the hologram medium based on the information generated by the first light receiving element; Hologram recording device comprising a. The method of claim 1, And a second light receiving element for receiving the control beam passing through the current track to generate current state information. The method of claim 1, The light source unit, A light source for generating light; A first polarizer for polarizing the light generated by the light source; A polarizing beam splitter which reflects a part of the light passing through the first polarizer and transmits a part thereof; And A second polarizer for polarizing the light transmitted through the polarization beam splitter to generate a reference beam; Hologram recording device further comprising a. The hologram recording apparatus of claim 1, wherein the control beam has the same polarization state as that of the reference beam. The method of claim 1, The light source unit further comprises a light source for generating a signal beam. Generating a reference beam, a signal beam, and a control beam; Irradiating the reference beam, the signal beam, and the control beam to a previous track of a hologram medium to record data and track information; And Recording data and track information in the current track; Hologram recording method comprising a. The method of claim 6, The step of recording data and track information in the current track, Receiving the reference beam irradiated to the previous track to generate information for track interval control; And Driving an actuator to maintain a gap between a previous track and a current track based on the generated information; Hologram recording method comprising a. The method of claim 6, The step of recording data and track information in the current track, And receiving the control beam irradiated to the current track to generate information for position and tilt control of the hologram medium. The method of claim 6, Generating the reference beam, the signal beam and the control beam, Polarizing the light generated from the light source, Reflecting and transmitting a portion of the first polarized light; And Polarizing the transmitted light to generate a reference beam; Hologram recording method comprising a. A light source unit generating a reference beam; A light receiving element receiving the reference beam passing through the track of the hologram medium to generate the hologram medium current state information; An actuator for controlling the position of the hologram medium based on the information generated by the light receiving element; And A reading element that receives a reference beam that has passed through the track of the hologram medium to read information; Hologram playback device comprising a. The method of claim 10, The light source unit, A light source for generating light; A first polarizer for polarizing the light generated by the light source; A polarizing beam splitter which reflects a part of the light passing through the first polarizer and transmits a part thereof; And A second polarizer for polarizing the light transmitted through the polarization beam splitter to generate a reference beam; Hologram playback device comprising a. Generating a reference beam; Receiving a reference beam that has passed through the track of the hologram medium to generate tilt state information of the hologram medium; Driving an actuator to compensate for the tilt of the medium based on the generated information; And Receiving and reading a reference beam that has passed through the hologram medium; Hologram playback method comprising a. The method of claim 12, Generating the reference beam, Generating light; A first polarizer for polarizing the light generated by the light source; Reflecting and partially transmitting some of the light polarized by the first polarizing element; And Polarizing the transmitted light to generate a reference beam; Hologram playback method comprising a. Data information recorded by the reference beam and the signal beam interference; And Track information recorded by the reference beam and the control beam interference; Hologram storage medium, characterized in that recorded. The method of claim 14, The reference beam and the control beam is a hologram storage medium, characterized in that the same polarization state.

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