KR20090062641A - A recording/reproducing method and an apparatus - Google Patents

A recording/reproducing method and an apparatus Download PDF

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Publication number
KR20090062641A
KR20090062641A KR1020070130010A KR20070130010A KR20090062641A KR 20090062641 A KR20090062641 A KR 20090062641A KR 1020070130010 A KR1020070130010 A KR 1020070130010A KR 20070130010 A KR20070130010 A KR 20070130010A KR 20090062641 A KR20090062641 A KR 20090062641A
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KR
South Korea
Prior art keywords
recording
signal
frequency distribution
state
frequency
Prior art date
Application number
KR1020070130010A
Other languages
Korean (ko)
Inventor
이정욱
Original Assignee
엘지전자 주식회사
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Application filed by 엘지전자 주식회사 filed Critical 엘지전자 주식회사
Priority to KR1020070130010A priority Critical patent/KR20090062641A/en
Publication of KR20090062641A publication Critical patent/KR20090062641A/en

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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/10009—Improvement or modification of read or write signals
    • G11B20/10037—A/D conversion, D/A conversion, sampling, slicing and digital quantisation or adjusting parameters thereof
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
    • G11B7/1353—Diffractive elements, e.g. holograms or gratings
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
    • G11B7/1395—Beam splitters or combiners
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B2220/00—Record carriers by type
    • G11B2220/20—Disc-shaped record carriers
    • G11B2220/25—Disc-shaped record carriers characterised in that the disc is based on a specific recording technology
    • G11B2220/2537—Optical discs

Abstract

In the recording / reproducing method and apparatus according to an aspect of the present invention, determining whether or not to synchronize the frequency distribution of the signal generated by the light reflected / diffracted from the recording medium and the parameter value of the recording technique for data recording / reproducing. And setting / changing them.

Description

Recording / Reproducing Method and Apparatus

The present invention relates to a recording / reproducing method and apparatus for setting / changing parameter values of a recording technique for data recording / reproducing by determining whether or not to synchronize a frequency distribution of a signal generated by light reflected / diffracted from a recording medium. A recording / reproducing method and apparatus.

A recording / reproducing apparatus using light records data on the recording medium or reproduces the recorded data by using a recording medium such as various disc types. Recently, high-quality video processing is required due to the advancement of consumer's preference, and as the video compression technology is developed, the recording medium is also required to be high in density. To this end, as a technology for high-density recording media, recently, near-field recording (Near Field Recording) by near-field optics such as Blue-ray Disc, HD-DVD, etc. NFR) devices are being developed. In addition, a recording medium having a multilayer recording layer has been developed.

The NFR applies SIL to the objective lens of the optical unit to increase the NA to record and reproduce. This NFR is a Gap Servo Controller that records the SIL of the pickup and the Gap of the media while maintaining a few tens of nanometers. Performance will be determined.

Here, while the pulse is being recorded, the specific pulse is weakened by the characteristics of the system and the disk, which causes a problem in that the data recording quality is lowered and the overall performance of the near field optical recording device is degraded.

Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to improve the performance of the system by obtaining values optimized for the system and disk while changing the write strategy of individual pulses. It is an object of the present invention to provide a recording / reproducing method and apparatus.

According to an aspect of the present invention, there is provided a recording / reproducing method for determining whether to synchronize with a frequency distribution of a signal generated by light reflected / diffracted from a recording medium and for recording / reproducing data. Setting / changing parameter values of the recording technique.

The recording / reproducing method may include storing parameter setting values of the recording technique of the state when the frequency of the signal indicates an optimal distribution state and the signal is in a synchronized state.

The recording / reproducing method may include changing parameter values of the recording technique of the state if the frequency of the signal does not represent an optimal distribution state or if the signal does not indicate a synchronized state.

The recording / reproducing method determines whether the frequency distribution of the signal is optimal based on the frequency distribution width and the peak-to-peak value, and whether the synchronization state is symmetric about the reference frequency. You can judge whether or not.

The recording / reproducing method is synchronized when the frequency distribution of the signal is narrow and the peak-to-peak value is maximum, and the frequency distribution is symmetrical about the reference frequency. A data recording / reproducing method, characterized in that.

The recording / reproducing method may further include measuring whether the signal is synchronized with the frequency distribution.

The recording / reproducing method may further include recording / reproducing an individual pulse to measure whether the signal is synchronized with a frequency distribution of the signal.

The recording / reproducing method may further include determining whether all parameter values of the recording technique of the other individual pulses are set.

The recording / reproducing method may further include recording / reproducing with the parameter setting values of the stored recording technique.

The parameter value of the recording technique may include at least one of a write pulse width, a power, a write speed, and a light source voltage.

 The recording / reproducing apparatus according to another aspect of the present invention for achieving the above object is an optical pickup that collects the light reflected / diffracted from the recording medium to generate a signal and whether or not synchronized with the frequency distribution of the signal generated from the optical pickup And a controller for setting / changing parameter values of a recording technique for data recording / reproducing.

The recording / reproducing apparatus may further include an external device that measures whether or not the signal is synchronized with the frequency distribution of the signal.

In this case, the external device may be a Time Inverval Analyzer.

The recording / reproducing method and apparatus according to the present invention as described in detail above has the effect of improving the performance of the entire system by recording and reproducing the individual pulses in an optimized state for the system.

Hereinafter, an embodiment of a recording / reproducing method and apparatus constituting the present invention will be described in detail. In adding reference numerals to the components of the following drawings, the same components are used the same reference numerals as much as possible even if they are displayed on different drawings. In this specification, for convenience of description, an example of a recording method and apparatus will be described in detail.

1 is a block diagram showing a system diagram of a recording / reproducing apparatus according to an embodiment of the present invention. The recording / reproducing apparatus will be described in detail with reference to the other drawings as follows.

Referring to FIG. 1, the recording / reproducing apparatus according to the present invention includes an optical pickup 100, a signal generator 110, a controller 120, a gap servo driver 130, a tracking servo driver 140, and a tilt servo driver 150. ), The microcomputer 160, the ATAPI I / F 170, the external device 180, and the like.

The optical pickup 100 is a portion for irradiating light to a recording medium and receiving light reflected on the recording medium to generate an electrical signal corresponding to the reflected light. The configuration of the optical pickup 100 will be described in detail later with reference to FIG. 2.

The signal generator 110 uses the electrical signal generated by the optical pickup 100 to record and reproduce a signal for data reproduction (also referred to as an 'RF signal') and a gap error signal (Gap error singal) required for servo control. It generates a "GE" and will be described later in detail), a tracking error signal (hereinafter referred to as "TE"), a tilt error signal (hereinafter referred to as "TE2") and the like.

The controller 120 receives the signal generated by the signal generator 110 and generates a control signal or a drive signal. For example, the controller 120 processes the GE to output a drive signal for controlling the gap between the lens unit 104 and the recording medium to the gap servo driver 130. Alternatively, the TE is processed to output a driving signal for tracking control to the tracking servo driver 140. Alternatively, the signal TE2 is processed to output a driving signal for tilt control to the tilt servo driver 150. In addition, the controller 120 may output a driving signal for varying the position focused on the recording medium to the gap servo driver 130 or a focus driver (not shown) provided separately.

In addition, the control unit 120 according to an embodiment of the present invention may determine / synchronize with the frequency distribution of the signal generated from the optical pickup to set / change parameter values of a recording technique for data recording / reproducing. have. If the frequency of the signal indicates an optimal distribution and the signal is in a synchronized state, the parameter setting value of the recording technique of the state is stored, and the frequency of the signal does not represent an optimal distribution or the signal is synchronized. If not, the parameter values of the recording technique of the state may be changed. The determination of the control unit 120 regarding whether the state is synchronized with the frequency distribution state will be described later with reference to FIGS. 4 and 5.

The gap servo driver 130 moves the optical pickup 100 or the lens unit 104 of the optical pickup up and down by driving an actuator (not shown) in the optical pickup 100. As a result, the distance between the lens unit 104 and the recording medium can be kept constant. The gap servo driver 130 may also serve as a focus servo. For example, the optical pickup 100 or the lens unit 104 of the optical pickup may follow the up and down movement along with the rotation of the recording medium according to a signal for focus control of the controller 120.

The tracking servo driver 140 corrects the position of the light by moving the optical pickup 100 or the lens unit 104 of the optical pickup in the radial direction by driving a tracking actuator (not shown) in the optical pickup 100. do. As a result, the optical pickup 100 or the lens unit 104 of the optical pickup can follow a predetermined track provided on the recording medium. In addition, the tracking servo driver 140 may move the optical pickup 100 or the lens unit 104 of the optical pickup in the radial direction corresponding to the movement command of the track.

The tilt servo driver 150 corrects the inclination between the lens unit and the recording medium, which will be described later, of the optical pickup 100 by driving or giving an offset to an actuator (not shown) in the optical pickup 100. Through this, an error due to the tilt between the lens unit and the recording medium (hereinafter referred to as 'tilt') that occurs when the recording medium itself is bent or tilted and seated in the drive can be corrected.

A host such as a PC may be connected to the recording and reproducing apparatus as described above. The host transmits a recording / reproducing command to the microcomputer 160 through the interface, receives the reproduced data from the decoder, and transmits data to be recorded to the encoder.

The microcomputer 160 controls the decoder, the encoder, and the controller 120 according to the recording / reproducing command of the host. In this case, the interface may generally use ATAPI (Advanced Technology Attached Packet Interface, 160).

ATAPI 170 is an interface standard between an optical recording / playback device such as a CD or DVD drive and a host, and is proposed to transmit data decoded by an optical recording / playback device to a host. It converts data into a packet protocol and transmits it.

The external device 180 measures whether or not to synchronize the frequency distribution of the signal generated by the light reflected / diffracted from the recording medium. In one embodiment of the present invention, the external device may include a Time Inverval Analyzer, which receives the signal from the signal generator 110 and peak-to-frequency the frequency and intensity of the measured frequency for each input signal. The result of the change to the peak value and the frequency numerical value width is transmitted to the controller 120.

2 is a block diagram showing an embodiment of the optical pickup 100 provided in the recording and reproducing apparatus of the present invention.

Referring to FIG. 2, the optical pickup 100 may include a light source 101, a separate combining unit 102 and 103, a lens unit 104, a light detecting unit 105, 106, and the like.

As the light source 101, a laser or the like having good directivity may be used. Therefore, the light source 101 is specifically a laser diode. The light emitted from the light source 101 to be irradiated onto the recording medium may be composed of parallel light. Therefore, it can be configured to include a lens, such as a collimate, to parallel the path of light on the path of light emitted from the light source.

The separate combining units 102 and 103 separate portions of paths of light incident in the same direction or synthesize paths of light incident in different directions. In the present embodiment, since the first separation synthesis unit 102 and the second separation synthesis unit 103 are provided, each of them will be described. The first separation synthesis unit 102 is a part that passes a part of the incident light and reflects some of the incident light (in this embodiment, the first separation synthesis unit 102 is a non-polarized beam splitter (NBS)). In addition, the second separation synthesis unit 103 is a portion that passes only polarization in a specific direction according to the polarization direction (in this embodiment, the second separation synthesis unit 103 is a polarized beam splitter (PBS)). For example, when using linear polarized light, the second separation synthesis unit 103 may be configured to pass only the polarization component in the vertical direction and reflect the polarization component in the horizontal direction. Alternatively, it may be configured to pass only the polarization component in the horizontal direction and reflect the polarization component in the vertical direction.

The lens unit 104 is a portion that irradiates the recording medium with the light emitted from the light source 100 and condenses the light reflected from the recording medium again. In the present embodiment, the lens unit is a portion forming a near field, which will be described below in detail with reference to FIG. 3.

The light detectors 105 and 106 are parts for receiving and photoelectrically converting the reflected light to generate an electrical signal corresponding to the light amount of the reflected light. In the present embodiment, the first light detector 105 and the second light detector 70 are provided. The first photodetector 105 and the second photodetector 106 may be configured by two photodetectors (PDA, PDB) that are specifically divided, for example, divided in the signal track direction or the radial direction of the recording medium. have. The photodetectors PDA and PDB generate electrical signals A and B proportional to the amount of light received. Alternatively, the light detectors 105 and 106 may be composed of four light detectors (PDA, PDB, PDC, PDD) divided into two in the signal track direction and the radial direction of the recording medium. Here, the configuration of the photodetecting elements constituting the photodetectors 105 and 106 is not limited to this embodiment, and various modifications may be made as necessary.

3 is a cross-sectional view schematically showing the lens unit 104 of the optical pickup constituting an embodiment of the present invention.

Referring to FIG. 3, the lens unit 104 may include an objective lens 104a and a high refractive index lens 104b.

The lens unit 104 further includes a lens having a high refractive index in addition to the objective lens 104a to increase the numerical aperture, thereby forming an evanescent wave, thereby forming a near field. Specifically, as shown in FIG. 3, the objective lens 104a and the high refractive index lens 104b provided on the path through which the light passing through the objective lens 104a enters the recording medium are included. In the present invention, the objective lens 104a and the high refractive index lens 104b provided in the lens unit 104 may be variously modified.

Here, the high refractive index lens 104b is referred to as a "near lens forming lens" for convenience of description. In a recording and reproducing apparatus using a near field, the near field forming lens 104b needs to be located very close to the recording medium. As shown in Fig. 3, the spacing (the spacing indicated by H) between the near field forming lens 104b and the recording medium should be maintained at the nanometer to micrometer level spacing. Specifically, the relationship between the lens unit 104 and the recording medium will be described as an example.

When the lens unit 104 and the recording medium are brought close to about 1/4 (or λ / 4) or less of the optical wavelength, a part of the light incident on the lens unit 104 at a critical angle or more is formed at the surface of the recording medium. A dissipation wave is formed without total reflection, and passes through the recording medium to reach the recording layer. The dissipated wave that has reached the recording layer can be used for recording and reproducing. This makes it possible to store high density bit information with light below the diffraction limit. However, when the distance between the lens unit 104 and the recording medium is greater than λ / 4 or more, the wavelength of the light loses the property of the dissipation wave and returns to the original wavelength, and the surface of the recording medium or the near field forming lens 104b Total reflection at the surface. In this case, dissipation waves cannot be formed, and recording and reproduction by the near field cannot be performed. Therefore, in the recording / reproducing apparatus using the near field, the lens section 104 is controlled so that the distance from the recording medium does not exceed approximately? / 4. Is the limit of the near field. That is, in order to use the near field, the lens unit 104 and the recording medium need to maintain a nanometer distance. In this embodiment, a gap error signal (hereinafter, referred to as 'GE') may be used as a method of maintaining the nanometer-level spacing. In addition, the objective lens 104a must maintain an alignment relationship with the near field forming lens 104b, and this alignment relationship can be easily disturbed when the objective lens 104a is moved. Therefore, the objective lens 104a is configured to be fixed and not to move. For example, one lens unit may be set by combining the objective lens 104a and the near field forming lens 104b with a barrel (not shown).

4 is a diagram showing the frequency distribution of individual pulses according to the present invention.

When the recording medium is stimulated with an individual pulse, a recording / reproducing signal is generated from the recording medium. The frequency distribution of the recording / reproducing signal can be represented by a time axis (x axis) and an intensity axis (y axis) as shown in FIG. have.

5 is a view showing a result of measuring the frequency distribution and synchronization of individual pulses according to the present invention through an external device. FIG. 5 is a diagram illustrating a result measured by a time interval analyzer in an external device, but the present invention is not limited to the embodiment shown in FIG. 5, and various modifications may be made as necessary.

With the frequency distribution of FIG. 4, the intensity of an individual frequency is represented on each x-axis of FIG. 5, and the frequency of the corresponding frequency is represented on each y-axis. By repeatedly measuring these individual frequency intensities and frequencies, the width of the parabola as shown in FIG. 5 is represented by a range of frequency distributions, and the vertical width is represented by a peak-to-peak value that is a difference between the highest and lowest values of the individual frequency intensities. Can be. In addition, the reference value may be represented by a reference frequency arbitrarily set by the user to find a parameter setting value of an optimal recording technique different for each disc.

At this time, whether the frequency distribution of the signal is optimal is determined by the frequency distribution width and the peak-to-peak value, and whether the synchronization state is determined by whether the frequency distribution state is symmetric about the reference frequency. can do. In more detail, whether or not the frequency distribution is optimal may be determined as a case where the frequency distribution width of the signal is narrow and the peak-to-peak value is maximum. It can be judged whether it is symmetrical about the center.

For example, three different types of results graphs are shown in FIG. 5, which shows that FIG. 5A has a narrower frequency distribution and a larger peak-to-peak value than FIG. 5B, and FIG. 5A shows a better frequency distribution. Indicates the state. That is, the frequency of the same or similar measurement in Figure 4 is repeated so that the graph of Figure 5a can be obtained. In addition, while FIG. 5A is symmetrical with respect to the reference frequency, FIG. 5C shows that the frequency distribution curve is shifted from the reference frequency, and FIG. 5A can be regarded as being synchronized unlike FIG. 5C. In summary, FIG. 5A has a better frequency distribution than FIG. 5B, and is in a synchronized state compared with FIG. 5C, showing the most optimal state among these three graphs.

A recording and reproducing method according to an embodiment of the present invention corresponding to the operation of the component of FIG. 1 will be described with reference to FIG.

6 is a flowchart illustrating an operation of a recording / playback method according to an embodiment of the present invention.

Referring to FIG. 6, when the optical pickup 100 collects and reflects the light reflected / diffracted from the recording medium due to the recording / reproducing when the individual pulses are recorded / reproduced in the recording medium (S10), the external device 180 generates a signal. In operation S20, the frequency distribution of the signal is measured and synchronized. The result of the synchronization with the frequency distribution measured by the external device 180 is as described above with reference to FIGS. 4 and 5.

The controller 120 determines whether the measurement result indicates synchronization with an optimal frequency distribution state (S30). In this case, whether the frequency distribution of the signal is optimal is determined by the frequency distribution width and the peak-to-peak value, and whether the synchronization state is represented by whether the frequency distribution state is symmetric about the reference frequency.

As a result of the determination, if the frequency of the signal does not represent an optimal distribution state or the signal does not indicate a synchronized state, the parameter values of the recording technique are changed by adjusting the recording pulse width, power, recording speed, light source voltage, etc. in the state. (S40). After changing the parameter, the external device 180 re-measures whether the signal is synchronized with the frequency distribution of the signal based on the changed parameter values to determine whether the controller 120 is in an optimal frequency distribution state or not. To judge.

However, as a result of the determination, if the frequency of the signal indicates an optimal distribution and the signal is synchronized, the parameter setting value of the recording technique of the state is stored (S50). The storage means that the parameter setting is optimized for a disc recorded with a specific T individual pulse, so a process of optimizing the parameter setting value in another T individual pulse state is necessary. Therefore, it is determined whether all parameter values of other individual pulse recording techniques are obtained (S60). Go through the process of S50. For example, a system capable of storing recording patterns from 2T to 8T would optimize parameter settings on discs recorded with 2T individual pulses and then set the parameter settings on discs recorded with all other individual pulses, such as the remaining 3T and 5T. To optimize.

If all the parameter values of the recording technique of all the individual pulses are set, this means that the current disk system is optimized, and then recording / reproducing using the stored parameter values (S80).

1 is a block diagram showing a system diagram of a recording / reproducing apparatus according to an embodiment of the present invention.

Fig. 2 is a block diagram showing an embodiment of the optical pickup 100 provided in the recording and reproducing apparatus of the present invention.

3 is a sectional view schematically showing a lens unit 104 of an optical pickup constituting an embodiment of the present invention.

4 shows the frequency distribution of individual pulses in accordance with the present invention.

5 is a view showing a result of measuring the frequency distribution and synchronization of individual pulses according to the present invention through an external device.

6 is a flowchart showing an operation of a recording / playback method according to an embodiment of the present invention;

Claims (13)

Determining whether to synchronize with a frequency distribution of a signal generated by the light reflected / diffracted from the recording medium; And Setting / changing parameter values of a recording technique for data recording / reproducing. The method of claim 1, And storing the parameter setting values of the recording technique of the state if the frequency of the signal indicates an optimal distribution state and the signal is in a synchronized state. The method of claim 1, Changing parameter values of a recording technique of the state if the frequency of the signal does not represent an optimal distribution state or the signal is in a synchronized state. The method of claim 2 or 3, Whether or not the frequency distribution of the signal is optimal is determined by the frequency distribution width and the peak-to-peak value, and whether or not the synchronization state is indicated is whether or not the frequency distribution state is symmetric about a reference frequency. How to play. The method of claim 4, wherein The frequency distribution is optimal when the frequency distribution width of the signal is narrow and the peak-to-peak value is maximum, and data recording is synchronized when the frequency distribution state is symmetrical about the reference frequency. How to play. The method according to any one of claims 1 to 3, And measuring whether or not the signal is synchronized with the frequency distribution of the signal. The method of claim 6, And recording / reproducing the individual pulses to measure whether or not the signal is synchronized with the frequency distribution of the signal. The method of claim 7, wherein And determining whether all parameter values of another individual pulse recording technique have been set. The method according to claim 1, wherein And recording / reproducing with the parameter setting values of the stored recording technique. The method of claim 1, The parameter value of the recording technique includes at least one of a recording pulse width, a power, a recording speed, and a light source voltage. An optical pickup for condensing the light reflected / diffracted from the recording medium to generate a signal; And And a controller for determining / synchronizing the frequency distribution of the signal generated from the optical pickup and setting / changing parameter values of a recording technique for data recording / reproducing. The method of claim 11, And an external device for measuring whether the signal is synchronized with the frequency distribution of the signal. 13. The data recording / reproducing apparatus according to claim 12, wherein said external device is a Time Inverval Analyzer.
KR1020070130010A 2007-12-13 2007-12-13 A recording/reproducing method and an apparatus KR20090062641A (en)

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