Method and apparatus for correcting edge interval of record signal in an optical record/read-out apparatus

Claim 2

A record signal correcting method for use in an optical recording/read-out apparatus wherein record signals are recorded that have a mark length bound by opposite edges and having an edge width extending therebetween, comprising the steps of: (a) recording N times, where N is an integer, a sequential record pattern B or record signals including a plurality of patterns A each having an n edge width, where n is an integer, and respectively being recorded in various combinations of said n edge widths; (b) reading out said pattern B as a signal thus recorded; (c) classifying the read-out signal into one of said patterns A and obtaining, for each edge position of each said pattern A, a shift quantity associated with said edge position relative to an edge position indicating an ideal edge recording position thereof; (d) generating and storing a table containing relationships between said shift quantities and said patterns A; (e) collating, for a data recording operation, a record signal of said data being recorded and having a pattern of the n edge widths with the patterns stored in said table to obtain a match; and (f) independently correcting head and tail edge shifts for each of said patterns A by a corresponding one of said shift quantities retrieved from said table responsive to the match resulting from said collating.

Claim 3

A record signal correcting method according to claim 1 wherein said table generating step further includes a step of interpolating edge position data based on the edge shift quantity of said pattern A, thereby attaining an edge shift quantity of a pattern D having edge widths not being classified into one of said patterns A.

Claim 4

A record signal correcting method according to claim 2 wherein said table generating step further includes a step of creating a table containing relationships between said patterns A and shift quantities of a last edge for each of said patterns A.

Claim 5

A record signal correcting method according to claim 1 wherein said recording step includes the steps of: recording a predetermined pattern C or record signals while changing a laser power for a recording operation in a stepwise manner; comparing a pulse length of a record signal of said pattern C with a corresponding pulse length of a read-out signal of said pattern C; and selecting as a laser power for use in the recording of said pattern B, based on a result of said comparison, a laser power used to record a pulse of which a difference between said pulse lengths is within an allowable range.

Claim 6

A record signal correcting method according to claim 4 wherein said recording step includes the steps of: recording said predetermined pattern C with a predetermined laser power; comparing a pulse length of the read-out signal of said pattern C with a pulse length of a record signal corresponding thereto; selecting, when a difference between said pulse lengths is within an allowable range as a result of said comparison, said predetermined laser power as a laser power for use in the recording of said pattern B; and recording, when the difference between said pulse lengths is beyond the allowable range as a result of said comparison, said pattern C while changing said predetermined laser power in a stepwise manner.

Claim 7

A record signal correcting method according to claim 5 wherein said pulse length comparing step includes a step of checking a duty ratio between a pulse length and a gap length of said read-out signal.

Claim 8

A record signal correcting method according to claim 3 wherein said table producing step includes the steps of: assigning digital values to a portion of addresses of a memory and data and further assigning the digital values to be associated with lengths respectively of the pulses and gaps constituting said patterns A of said read-out signal; assigning to remaining addresses of said memory a digital value corresponding to a shift quantity of the last edge of said patterns A; and writing said assigned data in the memory at a memory position specified by said assigned address.

Claim 9

A record signal correcting method according to claim 7 wherein said interpolating step includes the steps of: obtaining, for a zero data position in a memory space in which measured data of an edge shift quantity cannot be attained, said measured data for positions in said memory space nearest to said zero data position in a plurality of data address directions; and assigning weights to said plurality of measured data depending on distances respectively from said zero data position to obtain a mean value thereof, and thereafter setting the mean value as data of said zero data position.

Claim 10

A record signal correcting method according to claim 8 wherein said correcting step includes the steps of: reading data from the memory based on a memory address represented by digital values respectively corresponding to the matched pulse and gap lengths; and correcting, based on said data thus read from the memory, an interval of a last edge of said collated record signal.

Claim 11

A record signal correcting apparatus for use in an optical recording/read-out apparatus wherein record signals are recorded that have a mark length bound by opposite edges and having an edge width extending therebetween, comprising: (a) means for recording on an optical disk N times, where N is an integer, a record pattern sequence B of record signals including a plurality of patterns A each having an n edge width, where n is an integer, and respectively being recorded in various combinations of said n edge widths; (b) means for reading out said recorded pattern B as a signal from the optical disk; (c) means for classifying the read-out signal into one of said patterns A and for obtaining for each edge position of each said pattern A, a shift quantity associated with said edge position relative to an edge position indicating an ideal recording position thereof; (d) means for generating and storing therein a table containing relationships between said shift quantities and said patterns A; (e) means for collating a record signal of data being recorded and having a pattern of the n edge widths with the patterns stored in said table to obtain a match; and (f) means for independently correcting head and tail edge shifts for each of said patterns A by a corresponding one of said shift quantities retrieved from said table responsive to the match resulting from said collating.

Claim 12

A record signal correcting apparatus for use in an optical recording/read-out apparatus wherein record signals are recorded that have a mark length bound by opposite edges and having an edge width extending therebetween, comprising: (a) means for recording on an optical disk N times, where N is an integer, a record pattern sequence B of record signals including a plurality of patterns A each having an n edge width, where n is an integer, and respectively being recorded in various combinations of said n edge widths; (b) means for reading out said recorded pattern B as a signal from the optical disk; (c) means for classifying the read-out signal into one of said patterns A and for obtaining for each edge position of each said pattern A, a shift quantity associated with said edge position relative to an edge position indicating an ideal recording position thereof; (d) means for generating and storing therein a table containing relationships between said shift quantities and said patterns A; (e) means for collating a record signal of data being recorded and having a pattern of the n edge widths with the patterns stored in said table to obtain a match; and (f) means for independently correcting head and tail edge shifts for each of said patterns A by a corresponding one of said shift quantities retrieved from said table responsive to the match resulting from said collating.

Claim 13

A record signal correcting apparatus according to claim 10 wherein said shift quantity obtaining means includes: means for interpolating edge position data based on the edge shift quantity of said pattern A, thereby attaining an edge shift quantity of a pattern D having n edge widths and not being classified into said pattern A; and means for writing the value thus obtained through said interpolation as data in said table.

Claim 14

A record signal correcting apparatus according to claim 11 wherein said shift quantity obtaining means includes means for attaining a shift quantity of a last edge of said pattern A.

Claim 15

A record signal correcting apparatus according to claim 9 wherein said record means includes: means for changing the laser power in a stepwise manner when a predetermined pattern C is recorded; means for comparing a pulse length of a read-out signal of said pattern C with a corresponding pulse length of a record signal of said pattern C; and means for selecting a laser power used to record a pulse concerning which a difference between said pulse lengths is within an allowable range as a laser power for use in the recording of said pattern B, based on a result of said comparison.

Claim 16

A record signal correcting apparatus according to claim 13 wherein said record means includes: means for comparing a pulse length of the read-out signal of said pattern C recorded with a predetermined laser power with a pulse length of a record signal corresponding thereto; means for selecting, when a difference between said pulse lengths is within an allowable range as a result of said comparison, said predetermined laser power as a laser power for use in the recording of said pattern B; and means for recording, when the difference between said pulse lengths is beyond the allowable range as a result of said comparison, said pattern C while changing said predetermined laser power in a stepwise manner.

Claim 17

A record signal correcting apparatus according to claim 14 wherein said pulse length comparing means includes means for checking a duty ratio between a pulse length and a gap length of said read-out signal.

Claim 18

A record signal correcting apparatus according to claim 11 wherein said table storing means includes: means for assigning digital values to a portion of addresses of a memory and data, the digital values being respectively associated with lengths respectively of the pulses and gaps constituting said pattern A of said read-out signal; means for assigning to remaining addresses of said memory a digital value corresponding to a shift quantity of the last edge of said pattern A; and means for writing said assigned data in the memory at a memory position specified by said assigned address.

Claim 19

A record signal correcting apparatus according to claim 16 wherein said shift quantity obtaining means includes: means for obtaining, for a 0 data position in a memory space in which measured data of an edge shift quantity cannot be attained, said measured data for positions nearest to said 0 data position in a plurality of directions; and means for assigning weights to said plurality of measured data depending on distances respectively from said 0 data position to obtain a mean value thereof, thereby writing the mean value as data of said 0 data position.

Claim 20

A record signal correcting apparatus according to claim 17 wherein said correcting means includes: means for reading data from the memory based on a memory address represented by digital values respectively corresponding to the matched pulse and gap lengths; and means for correcting, based on said data thus read from the memory, an interval of a last edge of said collated record signal.