HK1087524B - Information storage medium and method and apparatus of recording and/or reproducing data on and/or from the same - Google Patents

Description

Information storage medium, and method and apparatus for recording and/or reproducing data on and/or from the same

Technical Field

The present invention relates to an optical information storage medium on which tracking polarity data (tracking polarity data) corresponding to the form of pits is recorded, and a method and apparatus for recording and/or reproducing data on and/or from the optical information storage medium.

Background

General optical discs as optical information storage media are classified into Compact Discs (CDs) or Digital Versatile Discs (DVDs) according to their information storage capacities. Optical discs may also be classified as Mini Discs (MD) having a diameter of 65mm or less. In addition, a disc having a recording capacity of 20GB or more is being developed.

Optical discs may also be classified as read-only discs or rewritable discs. Examples of read-only disks are CD-ROM (read-only memory) and DVD-ROM. Examples of rewritable disks are CD + -R/RW, DVD + -R/RW and DVD-RAM (random access memory). The CD-R and the DVD-R can perform recording only once, the CD-RW and the DVD-RW can perform recording and/or reproduction about 1000 times, and the DVD-RAM can perform recording and/or reproduction tens of thousands of times.

Generally, data is recorded as pits on a reproduction-only disc or a read-only disc. Since the rewritable disc is coated with the phase change material, data is recorded thereon according to the phase change.

In an apparatus for recording data on or reproducing data from an optical disc, a pickup accurately tracks a track on which user data is recorded and receives a laser beam reflected from the track, thereby reading the user data. A signal used when the pickup tracks a track is called a tracking signal (tracking signal). The tracking signal is obtained from a photodiode having a plurality of portions receiving the laser beam, and signals obtained from light received by the respective receiving portions are added or subtracted. The tracking signal is formed as an S-letter type curve in which left and right polarities are opposite to each other around the center thereof.

The tracking signals have different polarities depending on the type of the optical disc, i.e., physical characteristics of the recording layer, such as physical shapes of pits, physical shapes of tracks, and the like. For example, fig. 1A and 1B show a groove track G and a land track L arranged in an opposite manner. In fig. 1A, the tracking signal has a polarity that changes from (+) to (-) for example. In fig. 1B, the tracking signal has a polarity that changes from (-) to (+). As described above, the polarity of the tracking signal is divided into a polarity changing from (+) to (-) or a polarity changing from (-) to (+). The tracking signal is processed differently according to the polarity of the tracking signal. Therefore, if the polarity of the tracking signal is erroneously recognized, the data cannot be correctly reproduced. Accordingly, when the optical disc is loaded, the conventional recording and/or reproducing apparatus recognizes the polarity of the tracking signal through trial and error and then tracks a track on which user data has been recorded based on information on the recognized polarity. In this way, user data is read from the optical disc.

DISCLOSURE OF THE INVENTION

Technical problem

Therefore, the conventional reproducing apparatus takes a certain time to obtain information on the polarity of the tracking signal before reading out the user data. This prevents immediate reproduction of user data.

The polarity of the tracking signal can be changed by the physical shape of the pits. The physical shape of the pits may be different according to the type of disc. However, in the related art, additional information regarding the polarity of a tracking signal depending on the physical shape of a pit is not recorded on an optical disc, so that the reliability of data recording and/or reproduction is lowered. In addition, the conventional reproducing apparatus takes a few times to obtain information on the polarity of the tracking signal through trial and error, delaying recording and/or reproduction.

Technical solution

The present invention provides an optical information storage medium on which information about a tracking polarity depending on a pit shape, particularly information about a push-pull polarity, has been recorded, and a method of recording and/or reproducing data on and/or from the optical information storage medium.

According to an aspect of the present invention, there is provided an information storage medium having at least one information storage layer, wherein data is recorded in the form of protruding or indented pits in all or a partial area of the information storage medium, and information regarding the protruding or indented pits is recorded.

According to an aspect of the invention, the information on the protruding or indented pits is push-pull polarity information.

According to an aspect of the invention, information regarding the protruding or indented pits is recorded in or before a frame sync.

According to an aspect of the present invention, the information storage medium includes a Burst Cutting Area (BCA) and a lead-in area, one of which stores information regarding the protruding or indented pits.

According to an aspect of the present invention, the protruding or indented pits may be wobble pits.

According to an aspect of the invention, the data is decoded by performing an exclusive or operation on the push-pull polarity information and the data reproduced from the protruding or indented pits.

According to another aspect of the present invention, there is provided a method of recording and/or reproducing data on and/or from an information storage medium having at least one information storage layer, the method including: recording data in the form of protruding or indented pits in all or a partial area of the information storage medium; and recording information on the protruding or indented pits.

The method further comprises the following steps: reproducing push-pull polarity information; and recording or reproducing data on or from the information storage medium by performing tracking on the basis of the reproduced push-pull polarity information.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Advantageous effects

In the information storage medium according to the present invention, tracking polarity information (i.e., push-pull polarity information) regarding protruding and indented pits is recorded so that data is reliably recorded or reproduced without trial and error for obtaining the tracking polarity information. In addition, if data is recorded in the form of pits, each pit may have various shapes, such as indented or protruding pits.

Drawings

The above and/or other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:

fig. 1A and 1B show different tracking polarities depending on the configuration of a groove track and a land track;

FIG. 2A illustrates a protruding pit formed on a substrate of an information storage medium according to an embodiment of the present invention;

FIG. 2B illustrates indented pits formed on a substrate of an information storage medium according to an embodiment of the present invention;

fig. 3A is a graph showing amplitudes of a differential phase identification (DPD) signal and a Radio Frequency (RF) signal versus time in an information storage medium on which data is formed as pits of protrusions;

FIG. 3B is a graph showing amplitudes of DPD signals and RF signals versus time in an information storage medium on which data is formed as indented pits;

fig. 4A is a graph showing a push-pull signal with respect to time in an information storage medium on which data is formed as pits of protrusions;

fig. 4B is a graph showing a push-pull signal with respect to time in an information storage medium on which data is formed as indented pits;

FIG. 5 illustrates an example in which tracking polarity data is recorded in a sync pattern on an information storage medium according to an embodiment of the present invention;

fig. 6A and 6B illustrate different examples of locations of an information storage medium in which tracking polarity information has been recorded in a specific pattern according to an embodiment of the present invention;

FIGS. 7A and 7B illustrate different example layouts of an information storage medium according to another embodiment of the present invention;

fig. 8A schematically shows the structure of an information area of a recordable information storage medium;

FIG. 8B schematically shows the structure of an information area of a reproduction-only information storage medium;

fig. 9A shows a straight arrangement of pits, and fig. 9B shows a wobbling arrangement of pits;

fig. 10 illustrates an example in which tracking polarity information has been recorded on an information storage medium according to another embodiment of the present invention;

fig. 11A and 11B are diagrams illustrating a decoding method based on an exclusive or (XOR) operation of tracking polarity data and data detected from a data frame in an information storage medium according to another embodiment of the present invention;

fig. 12 is a flowchart illustrating a data recording and/or reproducing method according to another embodiment of the present invention; and

fig. 13 schematically illustrates an apparatus for recording and/or reproducing data in and/or from an information recording medium according to the present invention.

Modes for carrying out the invention

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.

As shown in fig. 2A, in the optical information storage medium according to an embodiment of the present invention, data is recorded as protruding pits 10 on a substrate 5. On the other hand, as shown in fig. 2B, data is recorded as indented pits 13 on the substrate 5. Information regarding the protruding pits 10 and the indented pits 13 is recorded in the optical information storage medium.

The information regarding the protruding pits 10 and the indented pits 13 may be tracking polarity information.

When data has been recorded in the form of protruding pits 10, the tracking signal may have a polarity that changes from (+) to (-) for example. When data has been recorded in the form of indented pits 13, the tracking signal may have a polarity that changes from (-) to (+). As described above, since the polarity of the tracking signal changes according to the shape of the pit, the tracking signal must be differently performed according to the shape of the pit so that data can be normally recorded or reproduced.

The conditions and results of the simulations performed to determine the tracking signal characteristics are shown in table 1.

[ Table 1]

LD wavelength (lambda)	400nm
		Numerical aperture of objective lens	0.85
Trench structure	Track pitch: 0.32 μm
		Minimum mark length	0.149μm
Width of mark	0.15μm
		Modulation technique	RLL(1，7)

In table 1, the RLL modulation technique is based on how many bits '0' exist between two bits '1'. RRL (m, k) indicates that at least m bits of '0' exist between two bits of '1' and at most k bits of '0' exist therebetween. For example, RLL (1, 7) indicates that at least one bit '0' exists between two bits '1' and at most 7 bits '0' exists therebetween. According to the RRL (m, k) modulation technique, when m is 1, data '1010101' is recorded, and a pit having a length of 2T exists between two bits '1'. When m is 7, data '10000000100000001' is recorded and a pit having a length of 8T exists between two bits '1'. Here, T denotes the length of the minimum mark, i.e., the minimum pit. Therefore, in the RLL (1, 7) modulation method, data is recorded in the form of pits and spaces ranging in length from 2T to 8T.

Fig. 3A shows a Radio Frequency (RF) signal and a differential phase identification (DPD) signal when data has been recorded in the form of protruding pits 10. Fig. 3B shows the RF signal and the DPD signal when data has been recorded in the form of indented pits 13. Referring to fig. 3A and 3B, the DPD signal does not depend on the shape of the pits.

Fig. 4A shows a push-pull signal when data has been recorded in the form of protruding pits 10, and fig. 4B shows a push-pull signal when data has been recorded in the form of indented pits 13. Referring to fig. 4A and 4B, the push-pull signal depends on the shape of the pits. Therefore, if data is reproduced or tracked by using the push-pull signal, information on the tracking polarity depending on the pit shape needs to be recorded. Thus, the information on the tracking polarity may be information on the polarity of the push-pull signal.

When recording information on the tracking polarity, as shown in fig. 5, the optical information storage medium according to an embodiment of the present invention includes a plurality of data frames 15, and information on the tracking polarity, i.e., push-pull polarity information. The push-pull polarity information may be recorded in a synchronization pattern on a frame sync 14, which frame sync 14 is included in front of an area comprising a predetermined number of data frames 15. The synchronization pattern may be a pattern that is not used as a pattern of user data or a pattern of specific bits. An example of a synchronization pattern is shown in fig. 5.

For example, the synchronization pattern may be formed of the same data repeated to represent tracking polarity information. If the value '1' is read out continuously, this means that data is recorded in the form of protruding pits. If the value '0' is continuously read, it means that data is recorded in the form of indented pits.

On the other hand, tracking polarity information, i.e., push-pull polarity information, may be recorded in a synchronization pattern of a specific pattern. For example, as shown in fig. 6A, data '010' is recorded in the frame sync 14 and represents a polarity changed from (+) to (-) thereof. In this case, if the data '101' is reproduced after tracking, the polarity of the tracking signal is inversely processed so that the data can be correctly reproduced. In fig. 6A, tracking polarity information has been recorded in the frame sync 14. However, as shown in fig. 6B, the tracking polarity information may be recorded in the predetermined area 12 in front of the frame sync 14. As described above, the tracking polarity information may be recorded in a part of the frame sync 14 or an area other than the frame sync 14.

Fig. 7A and 7B illustrate different layouts of an information storage medium according to another embodiment of the present invention. The information storage medium includes a clamping area (clamping area) C, a Burst Cutting Area (BCA) B, a lead-in area LI, a user data area U, and a lead-out area LO. The clamping area C indicates an area pressed down by a clamping means for clamping the disc.

The tracking polarity information may be recorded in the BCA area B. Unique information on the disc, such as a serial number, a manufacturing date/month/year, etc., may also be recorded in the BCA area B. In fig. 7A, the BCA area B is disposed between the clamping area C and the lead-in area LI. However, as shown in fig. 7B, the BCA area B may be disposed in front of the clamping area C.

When the tracking polarity information is recorded in the BCA area B, the tracking polarity information can be read out before the disc is tracked after the disc is loaded on a drive and focused. Therefore, the tracking servo system can be efficiently realized.

The tracking polarity information may also be recorded in the lead-in area LI instead of the BCA area B.

Fig. 8A shows a layout of a recordable information storage medium. Data may be recorded in the form of pits in portions of the recordable information storage medium, for example, in a lead-in area or a lead-out area. Information regarding the pit shape, i.e., tracking polarity information, can be recorded in the lead-in area, preferably, in the disc-related information area.

Fig. 8B shows a layout of a reproduction-only information storage medium. The tracking polarity information may be recorded in a disc-related information area included in the lead-in area. The tracking polarity information includes push-pull polarity information.

If data is recorded in the form of pits, the pits may be arranged in a straight line as shown in fig. 9A or in a wobbled line as shown in fig. 9B. When data has been recorded in the form of straight pits, the data recorded in the pits can be reproduced by using the sum channel, and tracking can be controlled by using the DPD or push-pull technique. If tracking is controlled by using the push-pull technique, information on the tracking polarity, i.e., push-pull polarity information is required.

When data has been recorded in the form of wobbled lines of pits (hereinafter, referred to as wobble pits), additional information can be recorded in the wobble itself. Data recorded in the wobbling pits can be reproduced using the sum channel, and additional information recorded in the wobbles can be reproduced using the push-pull channel.

The wobbling pits may be arranged in a single pattern including pits and spaces each having the same length. In a single pattern of pits, pits have no data, and wobbles may have data. In this case, the push-pull channel can be used as a channel for reproducing data stored in the wobbling pits.

When data is recorded in the form of wobbling pits, the data can be recorded by using various modulation techniques. For example, data may be recorded by using at least one of a phase modulation technique, a frequency modulation technique, and an amplitude modulation technique.

Referring to fig. 10, in an information storage medium according to another embodiment of the present invention, tracking polarity information is recorded in an area in front of a predetermined data frame, and although data is recorded in a different form, the different form of data can be decoded into the same data by performing an exclusive or (XOR) operation on the tracking polarity information and data read out as the tracking polarity information. The tracking polarity information may be recorded in the frame sync.

A method of decoding data by using an XOR operation when data has been recorded in the form of protruding pits or indented pits will now be described. When data recorded in the form of protruding pits is tracked, tracking polarity information is read as, for example, ' 0 ', and data is read as, for example, ' 11001. When the same data is recorded in the form of indented pits, tracking polarity information is read as, for example, ' 1 ', and data is read as, for example, ' 00110.

Referring to fig. 11A, if tracking polarity information on indented pits is recorded as data '0' and data detected from an nth data frame is '11001.', the tracking polarity data and the data detected from the nth data frame are subjected to an XOR operation to obtain decoded data '11001.'.

Referring to fig. 11B, if tracking polarity information on protruding pits is recorded as data '1' and data detected from an nth data frame is '00110.', the tracking polarity data and the data detected from the nth data frame are subjected to an XOR operation to obtain decoded data '11001.'.

As described above, since data is decoded by using an XOR operation on the tracking polarity data and the data reproduced from the pits, the data can be correctly reproduced and restored regardless of whether the pits are protruding pits or indented pits. In addition, decoded data can be obtained without requiring additional changes in the control operation.

In addition, by using the data read out by the tracking polarity information, that is, the push-pull polarity information, as the selection signal, it is possible to output as decoded data either directly or after the polarity of the data is inverted. In other words, if the tracking polarity information is recorded in a predetermined pattern and the read tracking polarity information is the same as the predetermined pattern, the data is directly decoded. However, if the tracking polarity information is recorded in a predetermined pattern and the read-out tracking polarity information is not identical to the predetermined pattern, the data is decoded after the polarity thereof is reversed.

The information storage medium according to the present invention may be used for a multi-layered information storage medium having at least two information storage layers as well as a single-layered information storage medium.

Fig. 12 is a flowchart illustrating a data recording and/or reproducing method according to an embodiment of the present invention. Referring to fig. 12, an information storage medium is loaded on a disc drive in operation 50. In operation 55, an optical pickup included in the disc drive reads tracking polarity information, i.e., push-pull polarity information, from the loaded information storage medium. The tracking polarity information is recorded as described in the above embodiments, and is used as a basis on which a tracking signal is detected or data is recorded and/or reproduced.

Since the tracking polarity is changed according to the protruding pits 10 of fig. 2A or the indented pits 13 of fig. 2B, the tracking signal is differently processed according to the tracking polarity information. If the tracking polarity information is recorded in the BCA area B, the information storage medium is first loaded onto the disc drive, then focus control is implemented, and the tracking polarity information is read from the BCA area B before data is read from the loaded information storage medium. Therefore, tracking control and information reproduction are reliable.

In operation 60, the disc drive records or reproduces data on or from the data area by performing tracking control without trial and error on the basis of the reproduced tracking polarity information, i.e., push-pull polarity information. In other words, the optical pickup provides the reproduced tracking polarity information to the disc drive, and the disc drive controls the optical pickup on the basis of the received information so that data is smoothly recorded on or reproduced from the information storage medium.

Data can be decoded by performing an XOR operation on the tracking polarity data and the data reproduced from the pits. Accordingly, data can be decoded regardless of the tracking polarity.

The data reproduced on the basis of the tracking polarity information may be directly output as decoded data or may be output as decoded data after the polarity thereof is reversed. In other words, if the tracking polarity information is recorded in a predetermined pattern and the read tracking polarity information is the same as the predetermined pattern, the data is directly decoded. On the other hand, if the tracking polarity information is recorded in a predetermined pattern and the read tracking polarity information is not identical to the predetermined pattern, the data is decoded after the polarity thereof is reversed.

Fig. 13 schematically shows an apparatus for recording and/or reproducing data in and/or from an information storage medium according to the present invention, the apparatus including: a pickup 50, a recording/reproducing signal processor 60, and a controller 70. More specifically, the picker 50 includes: a laser diode 51 for emitting light; a collimator lens 52 for collimating the light emitted by the laser diode 51; a beam splitter 54 for changing the path of incident light; and an objective lens 56 for focusing the light passing through the beam splitter 54 onto the information storage medium D.

The light reflected by the information storage medium D is reflected by the beam splitter 54 and received by a photodetector, for example, a 4-division photodetector 57. The light incident on the 4-division photodetector 57 is converted into an electric signal while passing through the arithmetic circuit 58. An RF signal, i.e., a sum signal is output through the first channel Ch1 and a differential signal used in the push-pull technique is output through the second channel Ch 2.

When the information storage medium D is loaded, the controller 70 controls the pickup 50 to project a light beam onto the information storage medium D and read out a signal into which the light beam reflected by the information storage medium D is converted by the signal processor 60. More specifically, the light beam reflected by the information storage medium D is applied to the photodetector 57 through the objective lens 56 and the beam splitter 54. The light incident on the photodetector 57 is converted into an electric signal by the arithmetic circuit 58, and the electric signal is output as an RF signal.

The signal processor 60 processes data according to the tracking polarity information read from the information storage medium D. The controller 70 controls the pickup 50 based on the data signal processed by the signal processor 60.

Claims (7)

1. A method of recording data on an information storage medium having at least one information storage layer, the method comprising:

recording data in the form of protruding or indented pits in all or a partial area of the information storage medium; and

recording tracking polarity information on the protruding or indented pits in a predetermined area of the information storage medium.

2. The method of claim 1, wherein information on the protruding or indented pits is recorded in or before a frame sync.

3. The method of claim 1, wherein a burst cutting area is included in the information storage medium to store tracking polarity information on the protruding or indented pits.

4. The method of claim 1, wherein a lead-in area is included in the information storage medium to store tracking polarity information on the protruding or indented pits.

5. The method of claim 1, wherein the protruding or indented pits are wobble pits.

6. The method of claim 5, wherein the additional information is recorded in a wobble of the wobbling pits.

7. The method of claim 6, wherein the additional information is recorded by using at least one of a phase modulation technique, a frequency modulation technique, and an amplitude modulation technique.