Compensation method and device for tracking operation of optical storage system

Abstract

An optical storage system includes a pickup head for picking up data from a storage medium. Firstly, the maxima of a tracking error signal and runout are obtained in a calibration procedure in a close loop formed by an optical pickup head, a pre-amplifier, a compensator, a band-pass filter and a maximum detector. A calibration factor is then defined and derived by using the obtained maxima and nominal factors of a power amplifier and the optical pickup head of the optical storage system. The path formed by the series-connected band-pass filter and maximum detector is then disabled, while the calculated calibration factor is then stored in the compensator. The optical storage system may operate in a close loop formed by the optical pick head, pre-amplifier, compensator, a power amplifier under a normal operation procedure so that the optical storage system may record or read data onto/from an optical disc under the compensation provided by the calibration factor.

1. A method for controlling a tracking operation of an optical storage system, said optical storage system comprising a pickup head for picking up data from a storage medium, said method comprising steps of:
 obtaining a maximum of a runout associated with a relative motion between said pickup head and said storage medium;  
 obtaining a maximum of a tracking output signal associated with a relative motion between said pickup head and said storage medium;  
 obtaining a value of a calibration factor by using said maximum of said runout, said maximum of said tracking output signal and element parameters associated with said computer  optical storage system; and  
 actuating said pickup head to operate under a compensation provided by said calibrated  calibration factor.  
 
     
     
       2. The method according to  claim 1  wherein said element parameters include a gain of a power amplifier coupled with said pickup head and a sensitivity of said pickup head. 
     
     
       3. The method according to  claim 1  wherein said maximum runout and maximum tracking output signal are obtained when said pickup head is in a status of focus-on but not track-on. 
     
     
       4. The method according to  claim 1  wherein said calibration factor K is defined by the following formula: 
       K   =         C   NOM     ×     D   NOM         C   ×   D           
 
       where
 C NOM  is a nominal value regarding a gain of a power amplifier coupled with said pickup head,  
 D NOM  is a nominal value regarding a sensitivity of said pickup head,  
 C is an actual gain of said power amplifier in operation,  
 D is an actual sensitivity of said optical pickup head in operation.  
 
     
     
       5. The method according to  claim 4  wherein 
         C   ×   D     ≈       R   MAX       TRO   MAX           
 
       where
 R MAX  is said maximum runout, and  
 TRO MAX  is said maximum of said tracking output signal.  
 
     
     
       6. The method according to  claim 1  wherein said calibration factor is obtained when said pickup head is in a status of track-on. 
     
     
       7. The method according to  claim 1  wherein said optical storage system is a compact disk-read only memory (CD-ROM) drive, a digital versatile disk-read only memory (DVD-ROM) drive, a compact disk-recordable (CD-R) drive, a compact disk-rewritable (CD-RW) drive, a digital versatile disk-recordable (DVD-R) drive, a digital versatile disk-rewritable (DVD-RW) drive, or a digital versatile disk-random access memory (DVD-RAM) drive. 
     
     
       8. A method for controlling a tracking operation of an optical storage system, said optical storage system comprising a pickup head for picking up data from a storage medium, said method comprising steps of:
 performing a calibration procedure for deriving a calibration factor by using nominal values of element parameters of said optical pickup head when said pickup head is in a status of focus-on but not track-on; and  
 performing a normal operation procedure for actuating said pickup head to record data on an optical disc or to read data from said disc.  
 
     
     
       9. The method according to  claim 8  wherein said element parameters include a gain of a power amplifier coupled with said pickup head and a sensitivity of said pickup head. 
     
     
       10. The method according to  claim 8  wherein said calibration procedure comprising steps of:
 obtaining a maximum of a runout associated with a relative motion between said pickup head and said storage medium;  
 obtaining a maximum of a tracking output signal associated with a relative motion between said pickup head and said storage medium; and  
 obtaining a value of a calibration factor by using said maximum of said runout, said maximum of said tracking output signal and element parameters associated with said computer  optical storage system.  
 
     
     
       11. The method according to  claim 8  wherein said calibration factor K is defined by the following formula: 
       K   =         C   NOM     ×     D   NOM         C   ×   D           
 
       where
 C NOM  is a nominal value regarding a gain of a power amplifier coupled with said pickup head,  
 D NOM  is a nominal value regarding a sensitivity of said pickup head,  
 C is an actual gain of said power amplifier in operation,  
 D is an actual sensitivity of said optical pickup head in operation.  
 
     
     
       12. The method according to  claim 10  wherein 
         C   ×   D     ≈       R   MAX       TRO   MAX           
 
       where
 R MAX  is said maximum runout, and  
 TRO MAX  is said maximum of said tracking output signal.  
 
     
     
       13. The method according to  claim 8  wherein said calibration factor is obtained when said pickup head is in a status of track-on. 
     
     
       14. The method according to  claim 8  wherein said optical storage system is a compact disk-read only memory (CD-ROM) drive, a digital versatile disk-read only memory (DVD-ROM) drive, a compact disk-recordable (CD-R) drive, a compact disk-rewritable (CD-RW) drive, a digital versatile disk-recordable (DVD-R) drive, a digital versatile disk-rewritable (DVD-RW) drive, or a digital versatile disk-random access memory (DVD-RAM) drive. 
     
     
       15. A compensation device of an optical storage system, comprising:
 a tracking error signal generator for generating a tracking error signal in responsive  response to a runout associated with a relative motion between a pickup head of said optical storage system and said  a storage medium;  
 a tracking output signal generator for generating a tracking error signal in responsive  response to said tracking error signal; and  
 calibration means for deriving a calibration factor in responsive  response to a maximum of said tracking output signal, a maximum runout, and nominal values of element parameters of said optical storage system, wherein said pickup head operates under a compensation provided by said calibration factor.  
 
     
     
       16. The compensation device according to  claim 15  wherein said tracking error signal generator is a pre-amplifier and said tracking output signal generator includes a compensator. 
     
     
       17. The compensation device according to  claim 15  wherein said element parameters include:
 a gain of a power amplifier that amplifies said tracking output signal for said pickup head; and  
 a nominal sensitivity of said pickup head.  
 
     
     
       18. The compensation device according to  claim 17  wherein said calibration factor K is defined by the following formula: 
       K   =         C   NOM     ×     D   NOM         C   ×   D           
 
       where
 C NOM  is said nominal gain of said power amplifier,  
 D NOM  is said nominal sensitivity of said pickup head,  
 C is an actual gain of said power amplifier in operation,  
 D is an actual sensitivity of said optical pickup head in operation.  
 
     
     
       19. The compensation device according to  claim 18  wherein 
         C   ×   D     ≈       R   MAX       TRO   MAX           
 
       where
 R MAX  is a maximum runout, and  
 TRO MAX  is said maximum of said tracking output signal.  
 
     
     
       20. The compensation device according to  claim 15  wherein said calibration means includes a maximum detector for finding said maximum tracking output signal from said tracking output signal. 
     
     
       21. The compensation device according to  claim 15  wherein said maximum of said tracking output signal and said maximum runout are obtained when said pickup head is in a status of focus-on but not track-on and said calibration factor is obtained when said pickup head is in a status of track-on. 
     
     
       22. The compensation device according to  claim 15  wherein said optical storage system is a compact disk-read only memory (CD-ROM) drive, a digital versatile disk-read only memory (DVD-ROM) drive, a compact disk-recordable (CD-R) drive, a compact disk-rewritable (CD-RW) drive, a digital versatile disk-recordable (DVD-R) drive, a digital versatile disk-rewritable (DVD-RW) drive, or a digital versatile disk-random access memory (DVD-RAM) drive. 
     
     
       23. An optical storage tracking apparatus for controlling a tracking operation of an optical storage system, said optical storage system comprising a pickup head for picking up data from an optical storage medium, comprising:
   means for obtaining a maximum of a runout associated with a relative motion between the pickup head and the storage medium;        means for obtaining a maximum of a tracking output signal associated with a relative motion between the pickup head and the storage medium;        means for obtaining a value of a calibration factor by using the maximum of the runout, the maximum of the tracking output signal and element parameters associated with the optical storage system; and        means for actuating the pickup head to operate under a compensation provided by the calibration factor.      
     
     
       24. The apparatus of  claim 23  wherein the element parameters include a gain of a power amplifier coupled with the pickup head and a sensitivity of the pickup head.  
     
     
       25. The apparatus of  claim 23  wherein the maximum runout and maximum tracking output signal are obtained when the pickup head is in a status of focus- on but not track - on.    
     
     
       26. The apparatus of  claim 23  wherein the calibration factor K is defined by the following formula: 
       K   =         C   NOM     ×     D   NOM         C   ×   D           
 
       
         where  
         
           C 
           NOM  
           is a nominal value regarding a gain of a power amplifier coupled with the pickup head,  
         
         
           D 
           NOM  
           is a nominal value regarding a sensitivity of the pickup head,  
         
         
           C is an actual gain of the power amplifier in operation,  
         
         
           D is an actual sensitivity of the optical pickup head in operation.  
         
       
     
     
       27. The apparatus of  claim 26  wherein 
         C   ×   D     ≈       R   MAX       TRO   MAX           
 
       
         where  
         
           R 
           MAX  
           is the maximum runout, and  
         
         
           TRO 
           MAX  
           is the maximum of the tracking output signal.  
         
       
     
     
       28. The apparatus of  claim 23  wherein the calibration factor is obtained when the pickup head is in a status of track- on.    
     
     
       29. A compensation apparatus of an optical storage system, comprising:
   a tracking error signal generator that generates a tracking error signal in response to a runout associated with a relative motion between a pickup head of the optical storage system and a storage medium that is accessed by the optical storage system;        a tracking output signal generator that generates a tracking error signal in response to the tracking error signal; and        a calibration component that derives a calibration factor based on a function of the tracking output signal, a runout, and nominal values of element parameters of the optical storage system, wherein the pickup head operates with an adjustment based on the calibration factor.      
     
     
       30. The compensation apparatus of  claim 29  wherein the tracking error signal generator is a pre- amplifier and the tracking output signal generator includes a compensator.    
     
     
       31. The compensation apparatus of  claim 29  wherein the element parameters include: a gain of a power amplifier that amplifies the tracking output signal for the pickup head; and a nominal sensitivity of the pickup head.  
     
     
       32. The compensation apparatus of  claim 31  wherein the calibration factor K is defined by the following formula: 
       K   =         C   NOM     ×     D   NOM         C   ×   D           
 
       
         where  
         
           C 
           NOM  
           is the nominal gain of the power amplifier,  
         
         
           D 
           NOM  
           is the nominal sensitivity of the pickup head,  
         
         
           C is an actual gain of the power amplifier in operation,  
         
         
           D is an actual sensitivity of the optical pickup head in operation.  
         
       
     
     
       33. The compensation apparatus of  claim 32  wherein the function is 
         C   ×   D     ≈       R   MAX       TRO   MAX           
 
       
         where  
         
           R 
           MAX  
           is a maximum runout, and  
         
         
           TRO 
           MAX  
           is a maximum of the tracking output signal.  
         
       
     
     
       34. The compensation apparatus of  claim 29  wherein the calibration component includes a maximum detector for finding a maximum tracking output signal from the tracking output signal.  
     
     
       35. The compensation apparatus of  claim 29  wherein the tracking output signal and the runout are obtained when the pickup head is in a status of focus- on but not track - on and the calibration factor is obtained when the pickup head is in a status of track - on.    
     
     
       36. A method for controlling a tracking operation of an optical storage system, the optical storage system comprising a pickup head for picking up data from a storage medium, comprising:
   deriving a calibration factor by using nominal values of element parameters of the optical pickup head when the pickup head is in a status of focus - on but not track - on; and        performing a normal operation procedure for actuating the pickup head to record data on an optical disc or to read data from the disc.      
     
     
       37. The method of  claim 36  wherein the element parameters include a gain of a power amplifier coupled with the pickup head and a sensitivity of the pickup head.  
     
     
       38. The method of  claim 36  wherein the deriving includes:
   obtaining a maximum of a runout associated with a relative motion between the pickup head and the storage medium;    
   obtaining a maximum of a tracking output signal associated with a relative motion between the pickup head and the storage medium; and    
   obtaining a value of a calibration factor by using the maximum of the runout, the maximum of the tracking output signal and element parameters associated with the optical storage system.    
 
     
     
       39. The method of  claim 36  wherein the calibration factor K is defined by the following formula: 
       K   =         C   NOM     ×     D   NOM         C   ×   D           
 
       
         where  
         
           C 
           NOM  
           is a nominal value regarding a gain of a power amplifier coupled with the pickup head,  
         
         
           D 
           NOM  
           is a nominal value regarding a sensitivity of the pickup head,  
         
         
           C is an actual gain of the power amplifier in operation,  
         
         
           D is an actual sensitivity of the optical pickup head in operation.  
         
       
     
     
       40. The method of  claim 39  wherein 
         C   ×   D     ≈       R   MAX       TRO   MAX           
 
       
         where  
         
           R 
           MAX  
           is the maximum runout, and  
         
         
           TRO 
           MAX  
           is the maximum of the tracking output signal.  
         
       
     
     
       41. The method of  claim 36  wherein the calibration factor is obtained when the pickup head is in a status of track- on.