Method and apparatus for recovering TOC and user information from an optical disk and using the TOC information to access user tracks

Abstract

An optical disk having a diameter less than 140 mm and, a thickness of 1.2 mm±0.1 mm, with a plurality of record tracks having data recorded thereon as embossed pits representing information and exhibiting a track pitch in the range between 0.646 μm and 1.05 μm; with the tracks being divided into a lead-in area, a program area and a lead-out area. The data includes table of contents (TOC) information recorded in a plurality of sectors in at least one TOC track and user information recorded in a plurality of sectors in user tracks; with the TOC information including addresses of start sectors recorded in the user tracks. The data (both user and TOC information) is encoded in a long distance error correction code having at least eight parity symbols, and is run length limited (RLL) modulated.

What is claimed is:  
     
       1. A method of reproducing data from an optical disk having a diameter less than 140 mm, a thickness of 1.2 mm±0.1 mm and a recording area divided into a lead-in area, a program area and a lead-out area, and wherein said data is recorded as embossed pits representing modulated, error-correction encoded user information in sectors in user tracks in said program area and representing modulated, error-correction encoded table of contents (TOC) information in sectors in at least one TOC track in said lead-in area with said TOC information including addresses of respective start sectors of said user tracks, the tracks having a track pitch in the range of 0.646 μm to 1.05 μm, said method comprising the steps of rotating said disk to obtain a constant linear velocity; projecting a pickup light beam through a lens for optically reading the rotating disk, said pickup light beam having a spatial frequency 1=λ/2NA, where the spatial frequency 1 is less than the track pitch, λ is the wavelength of the pickup light beam and NA is the numerical aperture of the lens; demodulating the data read from said disk; error correcting the demodulated data; separating the error corrected data into TOC information and user information; and using said TOC information to access and read selected user tracks in response to access instructions from a user. 
     
     
       2. The method of  claim 1  wherein said embossed pits have a linear density in the range between 0.237 μm per bit and 0.378 μm per bit. 
     
     
       3. The method of  claim 1  wherein said program area is located in a portion of the disk having a radius of from 20 mm to 65 mm. 
     
     
       4. The method of  claim 1  wherein each sector of said user and TOC tracks includes a sector header at a leading portion thereof, said sector header containing a sector sync pattern, a sector address, an error detection code, and subcode data. 
     
     
       5. The method of  claim 4 , wherein said subcode data in a given sector includes a subcode identifier and subcode information of a type identified by said subcode identifier. 
     
     
       6. The method of  claim 5  wherein said subcode identifier is a subcode address. 
     
     
       7. The method of  claim 5  wherein said subcode information includes track identifying data which identifies the track in which said given sector is recorded, copyright data which indicates whether user information in said track is permitted to be copied, and application identifying data which identifies a predetermined application allotted to said user information in said track. 
     
     
       8. The method of  claim 5  wherein said user information is picture information representing a respective picture, said picture information being recorded in at least one sector in a user track, and wherein said subcode information includes first distance information representing the distance from said given sector to the sector in which picture information representing a next preceding picture is recorded and second distance information representing the distance from said given sector to the sector in which picture information representing a next following picture is recorded. 
     
     
       9. The method of  claim 8  wherein said picture information is recorded in a lead sector and at least one following sector; and each said distance information represents the distance from said given sector to a next lead sector. 
     
     
       10. The method of  claim 9  wherein said picture information is compressed picture data selectively comprised of intraframe encoded picture data or predictively encoded picture data; and said first and second distance information each represents the distance from said given sector to the next lead sensor in which intraframe encoded picture data is recorded. 
     
     
       11. The method of  claim 5  wherein said user information is compressed picture data selectively comprised of different compression-encoded data representing respective pictures having a predetermined display sequence, and said subcode information includes type identifying information for identifying the type of compression-encoded data that is recorded in said given sector and sequence information for identifying the location in said display sequence of the picture represented by the compression-encoded data that is recorded in said given sector. 
     
     
       12. The method of  claim 5  wherein said user information is variable over time, and said subcode information includes time code data representing time information at which said user information is recorded. 
     
     
       13. The method of  claim 1  wherein said TOC information is representative of record/playback characteristics, diameter, recording capacity and number of record tracks of said disk. 
     
     
       14. The method of  claim 13  wherein said record/playback characteristics of said optical disk represent a read only disk, a write once disk or an erasable disk. 
     
     
       15. The method of  claim 1  wherein said TOC information includes TOC identification data for identifying a location of said at least one TOC track, data configuration of said at least one TOC track, and sector configuration of each of said plurality of sectors. 
     
     
       16. The method of  claim 1  wherein said TOC information includes data representative of disk size. 
     
     
       17. The method of  claim 1  wherein said TOC information includes data representative of a time code associated with said user information. 
     
     
       18. The method of  claim 1  wherein said user information is reproducible at a selected one of plural playback speeds; and said TOC information includes data representative of said selected playback speed. 
     
     
       19. The method of  claim 1  wherein said error-correction encoded information is formed of a pre-established number of C 1  code words, each C 1  code word containing information symbols, C 2  parity symbols each of which is derived from an information symbol included in a preassigned number of C 1  code words, and C 1  parity symbols each of which is derived from a predetermined number of symbols, including information symbols and C 2  parity symbols in said C 1  code word; and wherein said step of error correcting comprises using said C 1  parity symbols to error correct the C 1  code word which contains said C 1  parity symbols, using said C 2  parity symbols in said C 1  code word to error correct respective information symbols included in said preassigned number of C 1  code words, and forming an error corrected C 1  code word from the information symbols that had been corrected as a result of using said C 2  parity symbols. 
     
     
       20. The method of  claim 19  wherein said information symbols are recorded in a disarranged order, and wherein the step of error correcting further comprises rearranging the order of the symbols included in said error corrected code word to an arranged sequence. 
     
     
       21. The method of  claim 20  wherein said disarranged order is formed of odd information symbols recorded in an odd group and even information symbols recorded in an even group, and said arranged sequence is formed of sequential alternating odd and even information symbols. 
     
     
       22. The method of  claim 21  wherein each C 1  code word is formed of m symbols including n informational symbols, where m and n are integers; and wherein: 
       
         
           i=(k/m)−(kmod2)+1  
         
       
       
         
           j=(m/2)×(kmod2)+(kmodm)/2  
         
       
       where i is the sequential order of the error-corrected C 1  code words, j is the sequential order of the arranged sequence of m symbols in each error-corrected C 1  code word, and k is the disarranged order in which the m symbols are recorded on the disk. 
     
     
       23. The method of  claim 1  wherein the error correction encoded data is in a convolution code. 
     
     
       24. The method of  claim 1  wherein said data on the disk is modulated as a run length limited (RLL) code; and said step of demodulating includes decoding said RLL data. 
     
     
       25. The method of  claim 24  wherein said RLL code is (2,10) RLL code, such that successive data transitions are separated by no less than 2 data bit cells and by no more than 10 data bit cells. 
     
     
       26. The method of  claim 24  wherein said RLL code is recorded as 2n-bit information words, and said step of demodulating converts said 2n-bit information words into n-bit information words. 
     
     
       27. The method of  claim 26  wherein said step of demodulating comprises storing in each of a plurality of tables several n-bit information words, selecting a particular table as a function of a preceding 2n-bit information word read from said disk, and reading out from the selected table an n-bit information word which corresponds to the 2n-bit information word presently read from said disk. 
     
     
       28. The method of  claim 27  wherein at least one 2n-bit information word read from the disk corresponds to two different n-bit information words a first of which is stored in a first table and a second of which is stored in a second table, and wherein said step of selecting further comprises examining the 2n-bit information word which next follows said presently read 2n-bit information word to select said first or said second table as a function of said next-following 2n-bit information word. 
     
     
       29. The method of  claim 28  wherein said step of examining comprises sensing predetermined bits in said next-following 2n-bit information word to determine the table to be selected for said next-following 2n-bit information word, and selecting said first or said second table for said presently read 2n-bit information word depending upon the table to be selected for said next following 2n-bit information word. 
     
     
       30. Apparatus for reproducing data from an optical disk having a diameter less than 140 mm, a thickness of 1.2 mm±0.1 mm and a recording area divided into a lead-in area, a program area and a lead-out area, and wherein said data is recorded as embossed pits representing modulated, error-correction encoded information user information in sectors in user tracks in said program area and representing modulated, error-correction encoded table of contents (TOC) information in sectors in at least one TOC track in said lead-in area with said TOC information including addresses of respective start sectors of said user tracks, the tracks having a track pitch in the range of 0.646 μm to 1.05 μm, said apparatus comprising means for rotating said disk to obtain a constant linear velocity; pickup means for projecting a pickup light beam through a lens to optically read the rotating disk, said pickup light beam having a spatial frequency 1=λ/2NA, where the spatial frequency 1 is less than the track pitch, λ is the wavelength of the pickup light beam and NA is the numerical aperture of the lens; demodulating means for demodulating the data read from said disk; error correcting means for error correcting the demodulated data; means for separating the error corrected data into TOC information and user information; and control means responsive to said TOC information to access and read selected user tracks in response to access instructions from a user. 
     
     
       31. The apparatus of  claim 30  wherein said embossed pits have a linear density in the range between 0.237 μm per bit and 0.378 μm per bit. 
     
     
       32. The apparatus of  claim 30  wherein said program area is located in a portion of the disk having a radius of from 20 mm to 65 mm. 
     
     
       33. The apparatus of  claim 30  wherein each sector of at least said user tracks includes a sector header at a leading portion thereof, said sector header containing a sector sync pattern, a sector address, an error detection code, and subcode data. 
     
     
       34. The apparatus of  claim 33  wherein said subcode data in a given sector includes a subcode identifier and subcode information of a type identified by said subcode identifier. 
     
     
       35. The apparatus of  claim 34  wherein said subcode identifier is a subcode address. 
     
     
       36. The apparatus of  claim 34  wherein said subcode information includes track identifying data which identifies the track in which said given sector is recorded, copyright data which indicates whether user information in said track is permitted to be copied, and application identifying data which identifies a predetermined application allotted to said user information in said track. 
     
     
       37. The apparatus of  claim 34  wherein said user information is picture information representing a respective picture, said picture information being recorded in at least one sector in a user track, and wherein said subcode information includes first distance information representing the distance from said given sector to the sector in which picture information representing a next preceding picture is recorded and second distance information representing the distance from said given sector to the sector in which picture information representing a next following picture is recorded. 
     
     
       38. The apparatus of  claim 37  wherein said picture information is recorded in a lead sector and at least one following sector; and each said distance information represents the distance from said given sector to a next lead sector. 
     
     
       39. The apparatus of  claim 38  wherein said picture information is compressed picture data selectively comprised of intraframe encoded picture data or predictively encoded picture data; and said first and second distance information each represents the distance from said given sector to the next lead sector in which intraframe encoded picture data is recorded. 
     
     
       40. The apparatus of  claim 34  wherein said user information is compressed picture data selectively comprised of different compression-encoded data representing respective pictures having a predetermined display sequence, and said subcode information includes type identifying information for identifying the type of compression-encoded data that is recorded in said given sector and sequence information for identifying the location in said display sequence of the picture represented by the compression-encoded data that is recorded in said given sector. 
     
     
       41. The apparatus of  claim 34  wherein said user information is variable over time, and said subcode information includes time code data representing time information at which said user information is recorded. 
     
     
       42. The apparatus of  claim 30  wherein said TOC information is representative of record/playback characteristics, diameter, recording capacity and number of record tracks of said disk. 
     
     
       43. The apparatus of  claim 42  wherein said record/playback characteristics of said optical disk represent a read only disk, a write once disk or an erasable disk. 
     
     
       44. The apparatus of  claim 30  wherein said TOC information includes TOC identification data for identifying a location of said at least one TOC track, data configuration of said at least one TOC track, and sector configuration of each of said plurality of sectors. 
     
     
       45. The apparatus of  claim 30  wherein said TOC information includes data representative of disk size. 
     
     
       46. The apparatus of  claim 30  wherein said TOC information includes data representative of a time code associated with said user information. 
     
     
       47. The apparatus of  claim 30  wherein said user information is reproducible at a selected one of plural playback speeds; and said TOC information includes data representative of said selected playback speed. 
     
     
       48. The apparatus of  claim 30  wherein said error-correction encoded information is formed of a pre-established number of C 1  code words, each C 1  code word containing information symbols, C 2  parity symbols each of which is derived from an information symbol included in a preassigned number of C 1  code words, and C 1  parity symbols each of which is derived from a predetermined number of symbols, including information symbols and C 2  parity symbols in said C 1  code word; and wherein said error correcting means includes C 1  parity correction means to error correct a C 1  code word with C 1  parity symbols included therein, C 2  parity correction means to error correct respective information symbols included in said preassigned number of C 1  code word with C 2  parity symbols included in the error corrected C 1  code word, and means for forming an error corrected C 1  code word from the information symbols that had been corrected by using said C 2  parity correction means. 
     
     
       49. The apparatus of  claim 48  wherein said information symbols are recorded in a disarranged order; and wherein said error correcting means further includes rearranging means for rearranging the order of the symbols included in said error corrected C 1  code word to an arranged sequence. 
     
     
       50. The apparatus of  claim 49  wherein said disarranged order is formed of odd information symbols recorded in an odd group and even information symbols recorded in an even group, and said arranged sequence is formed of sequential alternating odd and even information symbols. 
     
     
       51. The apparatus of  claim 50  wherein each C 1  code word is formed of m symbols including n information symbols, where m and n are integers; and wherein: 
       
         
           i=(k/m)=(kmod2)+1  
         
       
       
         
           j=(m/2)×(kmod2)+(kmodm)/2  
         
       
       where i is the sequential order of the error-corrected C 1  code words, j is the sequential order of the arranged sequence of m symbols in each error-corrected C 1  code word, and k is the disarranged order in which the m symbols are recorded on the disk. 
     
     
       52. The apparatus of  claim 30  wherein the error correction encoded data is in a convolution code. 
     
     
       53. The apparatus of  claim 30  wherein said data on the disk is modulated as a run length limited (RLL) code; and said demodulating means includes an RLL decoder. 
     
     
       54. The apparatus of  claim 53  wherein said RLL code is (2,10) RLL code, such that successive data transitions are separated by no less than 2 data bit cells and by no more than 10 data bit cells. 
     
     
       55. The apparatus of  claim 53  wherein said RLL code is recorded as 2n-bit information words, and said RLL decoder converts said 2n-bit information words into n-bit information words. 
     
     
       56. The apparatus of  claim 55  wherein said RLL decoder comprises a plurality of storage tables, each for storing several n-bit information words, means for selecting a particular table as a function of a preceding 2n-bit information word read from said disk, and means for reading out from the selected table an n-bit information word which corresponds to the 2n-bit information word presently read from said disk. 
     
     
       57. The apparatus of  claim 56  wherein at least one 2n-bit information word read from the disk corresponds to two different n-bit information words a first of which is stored in a first table and a second of which is stored in a second table, and wherein said means for selecting includes means for examining the 2n-bit information word which next follows said presently read 2n-bit information word to control the selection of said first or said second table as a function of said next-following 2n-bit information word. 
     
     
       58. The apparatus of  claim 57  wherein said means for examining comprises means for sensing predetermined bits in said next-following 2n-bit information word to determine the table to be selected for said next-following 2n-bit information word, and means for controlling said selecting means to select said first or said second table for said presently read 2n-bit information word depending upon the table to be selected for said next following 2n-bit information word. 
     
     
       59. A method of reproducing data from an optical disk having a diameter less than  140  mm and a recording area divided into a lead- in area, a program area and a lead - out area, and wherein said data is recorded as pits representing modulated, error - correction encoded user information in sectors in user tracks in said program area and representing modulated, error - correction encoded control information in sectors in at least one control information region in said lead - in area or said program area with said control information including addresses of respective start sectors of said user tracks, the tracks having a track pitch in the range of  0 . 646  μm to  1 . 05  μm, said method comprising the steps of rotating said disk; projecting a pickup light beam through a lens for optically reading the rotating disk, said pickup light beam having a spatial frequency  1 =λ/ 2 NA, where the spatial frequency  1  is less than the track pitch, λ is the wavelength of the pickup light beam and NA is the numerical aperture of the lens; demodulating the data read from said disk; error correcting the demodulated data; separating the error corrected data into control information and user information; and using said control information to access and read selected user tracks in response to access instructions from a user.    
     
     
       60. Apparatus for reproducing data from an optical disk having a diameter less than  140  mm and a recording area divided into a lead- in area, a program area and a lead - out area, and wherein said data is recorded as pits representing modulated, error - correction encoded user information in sectors in user tracks in said program area and representing modulated, error - correction encoded control information in sectors in at least one control information region in said lead - in area or said program area with said control information including addresses of respective start sectors of said user tracks, the tracks having a track pitch in the range of  0 . 646  μm to  1 . 05  μm, said apparatus comprising means for rotating said disk; pickup means for projecting a pickup light beam through a lens for optically reading the rotating disk, said pickup light beam having a spatial frequency  1 =λ/ 2 NA, where the spatial frequency  1  is less than the track pitch, λ is the wavelength of the pickup light beam and NA is the numerical aperture of the lens; demodulating means for demodulating the data read from said disk; error correcting means for error correcting the demodulated data; means for separating the error corrected data into control information and user information; and control means responsive to said control information to access and read selected user tracks in response to access instructions from a user.    
     
     
       61. A method of reproducing data from an optical disk having a diameter less than  140  mm and a recording area divided into a lead- in area, a program area and a lead - out area, and wherein said data is recorded as pits representing modulated, error - correction encoded user information in sectors in user tracks in said program area and representing modulated, error - correction encoded control information in sectors in at least one control information region in said lead - in area or said program area with said control information, the tracks having a track pitch in the range of  0 . 7  μm to  0 . 9  μm, said method comprising the steps of rotating said disk; projecting a pickup light beam through a lens for optically reading the rotating disk, said pickup light beam having a spatial frequency  1 =λ/ 2 NA, where the spatial frequency  1  is less than the track pitch, λ is the wavelength of the pickup light beam and NA is the numerical aperture of the lens; demodulating the data read from said disk; error correcting the demodulated data; and separating the error corrected data into control information and user information.    
     
     
       62. Apparatus for reproducing data from an optical disk having a diameter less than  140  mm and a recording area divided into a lead- in area, a program area and a lead - out area, and wherein said data is recorded as pits representing modulated, error - correction encoded user information in sectors in user tracks in said program area and representing modulated, error - correction encoded control information in sectors in at least one control information region in said lead - in area or said program area with said control information, the tracks having a track pitch in the range of  0 . 7  μm to  0 . 9  μm, said apparatus comprising means for rotating said disk; pickup means for projecting a pickup light beam through a lens for optically reading the rotating disk, said pickup light beam having a spatial frequency  1 =λ/ 2 NA, where the spatial frequency  1  is less than the track pitch, λ is the wavelength of the pickup light beam and NA is the numerical aperture of the lens; demodulating means for demodulating the data read from said disk; error correcting means for correcting the demodulated data; and means for separating the error corrected data into control information and user information.