# Patent

## Title
Method of transferring data with respect to an optical information storage medium having different track pitches

## Abstract

An optical information storage medium includes a lead-in area, a lead-out area, and a user data area between the lead-in and lead-out areas and in which user data is recorded. Pits are formed in the lead-in area, the user data area, and the lead-out area, and a track pitch in all or a portion of the lead-in area is different from a track pitch in the remaining area of the optical information storage medium.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of application Ser. No. 11/242,886, filed on Oct. 5, 2005, now U.S. Pat. No. 7,411,891, which is a continuation of application Ser. No. 10/633,564, filed on Aug. 5, 2003, now U.S. Pat. No. 7,272,106, which claims the benefit of Korean Patent Application No. 2002-54756 filed on Sep. 10, 2002, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference in their entirety.


BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical information storage medium, and more particularly, to an optical information storage medium in which a track pitch in all or a portion of a lead-in area is different from a track pitch in remaining areas of the optical information storage medium so that the reliability of reproduction of important optical information storage medium-related information can be improved.
2. Description of the Related Art
Optical discs are generally used as information storage media of optical pickup devices, which record information on and/or reproduce information from the optical discs without contacting the optical discs. Optical discs are classified as either compact discs (CDs) or digital versatile discs (DVDs) according to their information recording capacity. CDs and DVDs further include 650 MB CD-Rs, CD-RWs, 4.7 GB DVD+RWs, DVD-random access memories (DVD-RAMs), DVD-R, DVD-rewritables (DVD-RWs), and so forth. Read-only discs include 650 MB CDs, 4.7 GB DVD-ROMs, and the like. Furthermore, high-density digital versatile discs (HD-DVDs) have been developed which have a recording capacity of 20 GB or more.
Various methods of increasing the recording capacity of optical discs have been studied. One method of increasing the recording capacity is to reduce a size of an optical spot focused on an optical disc. To reduce the size of the optical spot, the wavelength of a laser light source should be shortened or a numerical aperture (NA) of an objective lens should be increased. Further, the track pitch of the optical disc should be reduced. The track pitch refers to a minimum distance measured from a central line of one track to a central line of an adjacent track.
FIG. 1 illustrates the structure of a conventional DVD-ROM 110. The DVD-ROM 110 includes a user data area 105 in which user data is recorded. A lead-in area 100 is formed inside the user data area 105. A lead-out area 110 is formed outside the user data area 105. Data is recorded as dots in the lead-in area 100, the user data area 105, and the lead-out area 110. Also, the track pitch is 0.74 μm in the lead-in area 100, the user data area 105, and the lead-out area 110.
The track pitch tends to be reduced when increasing the recording capacity. However, since an optical spot focused on a track may reach an adjacent track, the possibility that cross-talk will occur becomes high as the track pitch is reduced. If cross-talk occurs, an abnormal reproduction signal is output. Thus, as the track pitch is reduced, there is an increase in abnormal reproduction of information.
In particular, if information is abnormally reproduced from an area in which is recorded important information in recording and/or reproducing data, this abnormal reproduction may gravely affect a recording and/or reproduction efficiency of a disc. Accordingly, the track pitch is required to be adjusted in accordance with an increase in the recording capacity of a storage medium and the importance of data.
SUMMARY OF THE INVENTION
The present invention provides an optical information storage medium in which a track pitch in an area in which is recorded important optical information storage medium-related information is different from a track pitch in a user data area in which is recorded user data so that the efficiency and reliability of the reproduction of data can be improved.
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.
According to an aspect of the present invention, an optical information storage medium includes a lead-in area, a lead-out area that is formed outside the lead-in area, and a user data area disposed between the lead-in and lead-out areas and in which user data is recorded where pits are formed in first tracks of the lead-in area, second tracks of remaining area including the user data area, and the lead-out area, and a track pitch of between adjacent first tracks in all or a portion of the lead-in area is different from a track pitch between adjacent second and/or third tracks in the remaining areas of the optical information storage medium.
It is preferable, but not required, that the first track pitch is greater than the second track pitch in the remaining area of the optical information storage medium.
According to an aspect of the invention, the lead-in area includes an area in which optical information storage medium-related information is recorded and an area in which copy protection information is recorded.
It is preferable, but not required, that the first track pitch in at least one of the areas of the lead-in area is greater than the second track pitch in the remaining area of the optical information storage medium.
It is preferable, but not required, that a ratio of tracking error signals detected in the area having the first track pitch to tracking error signals detected in the area having the second track pitch is 1.5 or more.



BRIEF DESCRIPTION OF THE DRAWINGS
The above and/or other features and advantages of the present invention will become more apparent and more readily appreciated by describing in detail exemplary embodiments thereof with reference to the accompanying drawings in which:
FIG. 1 illustrates the schematic structure of a conventional DVD-ROM;
FIG. 2 illustrates the schematic structure of an optical information storage medium according to an embodiment of the present invention;
FIG. 3A illustrates a phase tracking error signal (a differential phase detect (DPD) signal) when a track pitch is 0.32 μm;
FIG. 3B illustrates a phase tracking error signal (a DPD signal) when a track pitch is 0.35 μm; and
FIG. 4 is a block diagram of a recording and/or reproducing apparatus according to an embodiment of the present invention.



DETAILED DESCRIPTION OF THE EMBODIMENTS
Reference will now be made in detail to the present 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.
Referring to FIG. 2, an optical information storage medium 1000 according to an embodiment of the present invention includes a user data area 15, a lead-in area 10 which is formed inside the user data area 15, and a lead-out area 20 which is formed outside the user data area 15 and the lead-in area 10. A first track pitch in all or a portion of the lead-in area 10 is different from a second track pitch in remaining areas of the optical information storage medium 1000 including the user data and lead-out areas 15, 20.
The lead-in area 10 includes areas in which is recorded important data in reproduction from the optical information storage medium. Examples of the important data include optical information storage medium-related information, which is recorded in area 10a, and copy protection information, which is recorded in area 10b. The optical information storage medium-related information contains information on the type of storage medium (such as whether the medium 1000 is a recordable disc, write-once disc, or a read-only disc), information on the number of recording layers, information on the recording speed, and information on the size of the optical information storage medium 1000 (disc).
It is preferable, but not required, that a track pitch in at least one of the areas 10a and 10b is the first track pitch which is greater than the second track pitch in the remaining areas except the areas 10a and 10b. It is understood that additional important information in reproduction from the optical information storage medium 1000 may be recorded, and the track pitch in the entire lead-in area 10 may be the first track pitch which is greater than the second track pitch in the remaining areas of the optical information storage medium 1000.
The optical information storage medium according to an embodiment of the present invention is read-only optical information storage medium. The pits are formed everywhere in the lead-in area 10, the user data area 15, and the lead-out area 20. The pits are formed in a substrate in advance when manufacturing the read-only embodiment of the optical information storage medium 1000. If data is recorded as the pits, the pits can be formed in the lead-in area 10 and the user data area 15 without stopping a process of forming the pits. Thus, a process of manufacturing an optical information storage medium can be simplified and the time required for performing the process can be reduced.
One method of performing a tracking operation using the pits is a differential phase detect (DPD) method. For example, the DPD method is used to realize a track servo depending on the phase shift of an optical spot focused on a quarter photodetector. The DPD method is well known, and thus will not be described in detail herein. According to the DPD method, when track pitches on the optical information storage medium are different, output tracking error signals (such as differential phase tracking error signals) are different. For example, FIG. 3A illustrates a DPD signal when the track pitch is 0.32 μm, and FIG. 3B illustrates a DPD signal when the track pitch is 0.35 μm. Here, when the same reproduction power is output, the amplitude of a phase tracking error signal (a DPD signal) in the track pitch of 0.32 μm was about 1.46V. In contrast, the amplitude of the DPD signal in the track pitch of 0.35 μm was about 2.31V. Thus, the amplitude of the DPD signal when the track pitch is larger increased about 1.58 times the amplitude of the DPD signal when the track pitch is smaller. As can be seen in FIGS. 3A and 3B, as the track pitch is increased, the amplitude of the DPD signal is increased. As the amplitude of the DPD signal is increased, an error detecting efficiency is improved. Thus, the reproduction efficiency and reliability are improved as the track pitch is increased.
According to the result of simulations, it was found that, when the track pitch TP in the area 10a or the area 10b is I and the track pitch TP in the remaining areas of the optical information storage medium is II, it is preferable, but not required, that a ratio of a tracking error signal, particularly, a phase tracking error signal, to each of the track pitches TP is 1.5 or more as expressed by equation 1 set forth below:




  
    
      
        
          
            Tracking
            ⁢
            
              
            
            ⁢
            Error
            ⁢
            
              
            
            ⁢
            
              Signal
              
                TP
                =
                I
              
            
          
          
            Tracking
            ⁢
            
              
            
            ⁢
            Error
            ⁢
            
              
            
            ⁢
            
              Signal
              
                TP
                =
                II
              
            
          
        
        ≥
        1.5
      
    
    
      
        (
        1
        )
      
    
  




The optical information storage medium according to embodiments of the present invention can be applied to an optical information storage medium having one or more recording surfaces. In other words, if the optical information storage medium has a plurality of recording surfaces, the track pitch in all or a portion of a lead-in area of each of the plurality of recording surfaces can be greater than the track pitch in the remaining area of each of the plurality of recording surfaces. Accordingly, the track pitch in a portion of the lead-in area in which important information is recorded can be greater than the track pitch in the remaining area of the optical information storage medium so that the reproduction reliability of the important information can be increased.
While not specifically so limited, it is understood that the information storage medium can include the CD-Rs, CD-RWs, DVD-RWs, DVD-RAMs, DVD+RWs, as well as next generation high definition DVDs, such as Blu-ray discs and Advanced Optical Discs (AODs). Further, it is understood the information storage medium need not include lead-in and/or lead-out areas.
FIG. 4 is a block diagram of a recording and/or reproducing apparatus according to an embodiment of the present invention. Referring to FIG. 4, the recording apparatus includes a recording/reading unit 1001, a controller 1002, and a memory 1003. The recording/reading unit 1001 records data on a disc 1000, which is an embodiment of an information storage medium 1000 of the present invention, and reads the data from the disc 1000. The controller 1002 records and reproduces data from tracks having first and second track pitches according to the present invention as set forth above in relation to FIGS. 2, 3A, and 3B.
While not required in all aspects, it is understood that the controller 1002 can be computer implementing the method using a computer program encoded on a computer readable medium. The computer can be implemented as a chip having firmware, or can be a general or special purpose computer programmable to perform the method.
In addition, it is understood that, in order to achieve a recording capacity of several dozen gigabytes, the recording/reading unit 1001 could include a low wavelength, high numerical aperture type unit usable to record dozens of gigabytes of data on the disc 1000. Examples of such units include, but are not limited to, those units using light wavelengths of 405 nm and having numerical apertures of 0.85, those units compatible with Blu-ray discs, and/or those units compatible with Advanced Optical Discs (AOD).
As described above, in an optical information storage medium according to the present invention, the track pitch in an area, such as an optical information storage medium-related information area or a copy protection information area of a lead-in area, in which important information is recorded, is greater than the track pitch in the remaining areas of the optical information storage medium. Thus, reliable reproduction of the important information can be achieved without deteriorating a signal due to cross-talk occurring between adjacent tracks during reproduction of the important information.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and equivalents thereof.

## Claims

1. A method of transferring data with respect to an optical information storage medium, the medium comprising a single lead-in area, a single lead-out area, a single user data area formed between the lead-in and lead-out areas and in which user data is recorded, the method comprising:
transferring first data with respect to a portion of the lead-in area having a first track pitch between adjacent tracks; and
transferring second data with respect to at least one of the user data area and a remaining area of the lead-in area, the user data area and the remaining area of the lead-in area each having a second track pitch between adjacent tracks, and the second track pitch being other than the first track pitch;
wherein:
the portion of the lead-in area comprises optical information storage medium-related information;
the lead-in area, the user data area, and the lead-out area are arranged in sequence; and
the lead-in area is continuous.

2. The method of claim 1, wherein the first track pitch is greater than the second track pitch.

3. The method of claim 2, wherein the remaining area of the lead-in area comprises copy protection information.

4. The method of claim 3, wherein a ratio of tracking error signals detected in at least the portion of the lead-in area to tracking error signals detected in the remaining area of the lead-in area is 1.5 or more.

5. The method of claim 1, wherein the remaining area of the lead-in area comprises copy protection information.

6. The method of claim 1, wherein the optical information storage medium comprises more than one recording surface.

7. The method of claim 1, wherein the optical information storage medium-related information is recorded as pits in the portion of the lead-in area.

8. The method of claim 1, wherein the portion of the lead-in area having the first track pitch between adjacent tracks and the remaining area of the lead-in area having the second track pitch between adjacent tracks are continuous.

9. The method of claim 1, wherein the optical information storage medium-related information comprises information regarding reproducing speed and/or recording speed.

10. The method of claim 1, wherein the optical information storage medium-related information comprises a type of the optical information storage medium.

11. The method of claim 1, wherein the portion of the lead-in area having the first track pitch between adjacent tracks and the remaining area of the lead-in area having the second track pitch between adjacent tracks are contiguous in the lead-in area so that there is no gap in the lead-in area between the portion of the lead-in area having the first track pitch between adjacent tracks and the remaining area of the lead-in area having the second track pitch between adjacent tracks.

12. A method of transferring data with respect to an optical information storage medium, the medium comprising a single lead-in area, a single lead-out area, a single user data area formed between the lead-in and lead-out areas and in which user data is recorded, the method comprising:
transferring first data with respect to a portion of the lead-in area having a first track pitch between adjacent tracks; and
transferring second data with respect to at least one of the user data area and a remaining area of the lead-in area, the user data area and the remaining area of the lead-in area each having a second track pitch between adjacent tracks, and the second track pitch being other than the first track pitch;
wherein:
the portion of the lead-in area comprises optical information storage medium- related information;
the lead-in area, the user data area, and the lead-out area are arranged in sequence;
the optical information storage medium complies with a single disc format; and
the lead-in area is continuous.

13. The method of claim 12, wherein the single disc format is a CD format or a DVD format.

14. The method of claim 12, wherein the portion of the lead-in area having the first track pitch between adjacent tracks and the remaining area of the lead-in area having the second track pitch between adjacent tracks are contiguous in the lead-in area so that there is no gap in the lead-in area between the portion of the lead-in area having the first track pitch between adjacent tracks and the remaining area of the lead-in area having the second track pitch between adjacent tracks.

15. An optical information storage medium comprising:
a single lead-in area,
a single lead-out area, and
a single user data area formed between the lead-in and lead-out areas and in which user data is recorded;
wherein:
a portion of the lead-in area has a first track pitch between adjacent tracks, the user data area and a remaining area of the lead-in area each have a second track pitch between adjacent tracks, and the second track pitch is different than the first track pitch;
the portion of the lead-in area comprises optical information storage medium- related information, and the lead-in area, the user data area, and the lead-out area are arranged in sequence; and
the lead-in area is continuous.

16. The optical information storage medium of claim 15, wherein the optical information storage medium complies with a single disc format; and
the single disc format is a CD format or a DVD format.

17. The optical information storage medium of claim 15, wherein the optical information storage medium-related information comprises information regarding reproducing speed and/or recording speed.

18. The optical information storage medium of claim 15, wherein the optical information storage medium-related information comprises a type of the optical information storage medium.

19. The optical information storage medium of claim 15, wherein the portion of the lead-in area having the first track pitch between adjacent tracks and the remaining area of the lead-in area having the second track pitch between adjacent tracks are contiguous in the lead-in area so that there is no gap in the lead-in area between the portion of the lead-in area having the first track pitch between adjacent tracks and the remaining area of the lead-in area having the second track pitch between adjacent tracks.

20. An apparatus to optically transfer data with respect to an optical information storage medium comprising a single lead-in area, a single lead-out area, and a single user data area formed between the lead-in and lead-out areas and in which user data is recorded, the apparatus comprising:
an optical unit to emit light to transfer data with respect to the optical information storage medium; and
a controller to control the optical unit to transfer first data with respect to a first subarea of the lead-in area having a first track pitch between adjacent tracks, and second data with respect to a second subarea of the lead-in area, the lead-out area, and the data area each having a second track pitch between adjacent tracks;
wherein:
the second track pitch is different than the first track pitch; the first subarea of the lead-in area comprises optical information storage medium-related information, and the lead-in area, the user data area, and the lead-out area are arranged in sequence: and
the lead-in area is continuous.

21. The apparatus of claim 20, wherein the optical information storage medium complies with a single disc format; and
the single disc format is a CD format or a DVD format.

22. The apparatus of claim 20, wherein the optical information storage medium-related information comprises information regarding reproducing speed and/or recording speed.

23. The apparatus of claim 22, wherein the optical information storage medium-related information comprises a type of the optical information storage medium.

24. The apparatus of claim 20, wherein the first subarea and the second subarea are contiguous in the lead-in area so that there is no gap in the lead-in area between the first subarea and the second subarea.