Record carrier having a servo track with position information in accordance with a modulation type and permanent information in accordance with a different modulation type, and apparatus for scanning the record carrier

Abstract

A record carrier ( 1 ) has a servo track ( 4 ) indicating an information track ( 9 ) intended for recording information blocks. The servo track ( 4 ) has a periodic variation of a physical parameter at a predetermined frequency, usually called wobble. The servo track has modulated parts for encoding position information according to a predetermined type of modulation. The record carrier includes a management area in which the servo track includes permanent data. The permanent data is encoded using a different type of modulation, but using the variations of the same physical parameter. Direct digital modulation ( 41 ) is proposed for the different type of modulation.

1. A record carrier comprising a servo track indicating an information track intended for recording information blocks represented by marks, said servo track having a periodic variation of a physical parameter at a predetermined frequency and modulated parts for encoding position information according to a predetermined type of modulation, characterized in that the record carrier further comprises a management area in which the servo track comprises permanent data represented by further variations of said physical parameter, the further variations being modulated in accordance with a type of modulation different from said predetermined type of modulation. 
     
     
       2. The record carrier as claimed in  claim 1 , wherein the predetermined type of modulation is a type of frequency or phase modulation of the periodic variation and/or the different type of modulation is direct digital modulation in which logical values of bits are represented by displacements of the servo track in a transverse direction. 
     
     
       3. The record carrier as claimed in  claim 2 , wherein the direct digital modulation is a run-length limited modulation (RLL). 
     
     
       4. The record carrier as claimed in  claim 1 , wherein the permanent data comprises key blocks for copy-protection and/or digital rights management. 
     
     
       5. The record carrier as claimed in  claim 1 , wherein the management area is not intended for recording information. 
     
     
       6. A record carrier comprising a servo track indicating an information track intended for recording information blocks represented by marks, said servo track having a periodic variation of a physical parameter at a predetermined frequency and modulated parts for encoding position information according to a predetermined type of modulation, characterized in that the record carrier further comprises a management area in which the servo track comprises permanent data represented by further variations of said physical parameter, the further variations being modulated in accordance with a type of modulation different from said predetermined type of modulation,
 wherein the management area has a track pitch between neighboring tracks larger than the track pitch in the area of the record carrier covered by the servo track indicating the information track intended for recording information blocks.   
     
     
       7. A recording and/or playback device comprising means for writing and/or reading information blocks in an information track on a record carrier having a servo track ( 4 ) indicating the information track ( 9 ), said recording and/or playback device comprises means for scanning the servo track, and demodulation means for retrieving position information from a signal generated by a variation of a physical parameter of the servo track at a predetermined frequency, said servo track having modulated parts for encoding position information according to a predetermined type of modulation, characterized in that the recording and/or playback device further comprises further demodulation means of a type different from said demodulation means for retrieving management data from a management area in which the servo track comprises the management data represented by further variations of said physical parameter, the further variations being modulated in accordance with the different type of modulation. 
     
     
       8. The recording and/or playback device as claimed in  claim 7 , wherein the demodulation means demodulates frequency or phase modulation of the periodic variation and/or the further demodulation means demodulates direct digital modulation in which logical values of bits are represented by displacements of the servo track in transverse direction. 
     
     
       9. The recording and/or playback device as claimed in  claim 7 , wherein the further demodulation means decodes run-length limited modulation (RLL). 
     
     
       10. A method of manufacturing a record carrier, in which the record carrier is provided with a servo track indicating an information track intended for recording information blocks, said servo track being provided with a variation of a physical parameter at a predetermined frequency and modulated parts for encoding position information according to a predetermined type of modulation, characterized in that the record carrier comprises a management area in which the servo track comprises management data represented by further variations of said physical parameter, the further variations being modulated in accordance with a type of modulation different from said predetermined type of modulation. 
     
     
       11. Record carrier comprising a servo track indicating an information track for recording information blocks represented by marks, which servo track has a periodic variation of its lateral position at a predetermined frequency and modulated parts for encoding position information according to a predetermined type of modulation, being a type of frequency or phase modulation of the periodic variation, and
 wherein the record carrier comprises a management area in which the servo track comprises permanent data represented by further variations of its lateral position, the further variations being according to a different type of modulation, being a direct digital modulation.   
     
     
       12. Record carrier as claimed in claim 11, wherein the direct digital modulation is realized in that logical values of bits are represented by displacements of the servo track in a transverse direction. 
     
     
       13. Record carrier as claimed in claim 11, wherein the direct digital modulation is realized in that a transition from one side to another represents a 1 and no transition represents a 0. 
     
     
       14. Record carrier as claimed in claim 11, wherein the permanent data comprises key blocks for copy-protection and/or digital rights management. 
     
     
       15. Record carrier as claimed in claim 11, wherein there is an indication that the management area is not for recording information blocks. 
     
     
       16. Record carrier as claimed in claim 11, wherein the management area has a track pitch between neighboring tracks larger than the track pitch in the area of the record carrier covered by the servo track indicating the area of the information track for recording information blocks. 
     
     
       17. Recording and/or playback device comprising means for writing and/or reading information blocks in an information track on a record carrier that comprises a servo track indicating the information track, which device comprises means for scanning the servo track and demodulation means for retrieving position information from a signal generated by a periodic variation of its lateral position of the servo track at a predetermined frequency, which servo track has modulated parts for the encoding position information according to a predetermined type of modulation, being a type of frequency or phase modulation of the periodic variation, wherein the device comprises further demodulation means of a different type for retrieving management data from a management area in which the servo track comprises the management data represented by further variations of its lateral position, the further variations being according to the different type of modulation, being a direct digital modulation. 
     
     
       18. Device as claimed in claim 17, wherein the further demodulation means are suitable for demodulating a direct digital modulation in which logical values of bits are represented by displacements of the servo track in a transverse direction. 
     
     
       19. Device as claimed in claim 17, wherein the further demodulation means are suitable for demodulating a direct digital modulation wherein a transition from one side to another represents a 1 and no transition represents a 0. 
     
     
       20. Method of manufacturing a record carrier, in which the record carrier is provided with a servo track (4) indicating an information track for recording information blocks, which servo track is provided with a periodic variation of its lateral position at a predetermined frequency and modulated parts for encoding position information according to a predetermined type of modulation, being a type of frequency or phase modulation of the periodic variation, and
 wherein the record carrier comprises a management area in which the servo track comprises management data represented by further variations of its lateral position, the further variations being according to a different type of modulation, being a direct digital modulation.   
     
     
       21. Recording and/or playback device comprising:
 a read or write/read head for scanning an information track indicated by a servo track on a record carrier while providing a radiation beam for writing and/or reading information blocks in the information track and reading signals from the servo track,   a first demodulator for retrieving position information from one of the signals read from the servo track, the signal being generated by a periodic variation of its lateral position of the servo track at a predetermined frequency, which servo track has modulated parts for the encoding position information according to a predetermined type of modulation, being a type of frequency or phase modulation of the periodic variation,   a second demodulator of a different type for retrieving management data from a management area of the servo track from one of the signals read from the servo track, the signals being generated by further variations of the lateral position of the servo track, the management data being different than the position information, the further variations being according to the different type of modulation, being a direct digital modulation.