JPH05189882A - Recorder/reproducer - Google Patents

Abstract

PURPOSE:To provide a mark recording pattern in which reliability can be enhanced in the detection of special mark such as a sector mark and a recording pattern detector. CONSTITUTION:In an optical information recording/reproducing method wherein binary coded data along a track 50 on an optical disc are recorded/reproduced in circular pits 51 corresponding to '1' or '0' position thereof, identification marks each comprising a plurality of pits 100 elongated in the track direction are formed at predetermined intervals along the track 50 on the optical disc. The identification marks are then detected and data is recorded between thus detected identification marks.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording detection device for special marks such as sector marks on an optical disk.

[0002]

2. Description of the Related Art When recording and reproducing information on an optical disc, it is useful to mark the starting point of each recording unit in random access, read / write control and the like. Here, the above recording unit is called a sector, and the mark is called a sector mark. The sector mark is effective not only for the above control but also for facilitating the timing control at the time of reading and writing data and making the detection of the periodic signal highly reliable.

Incidentally, as a conventional technique relating to the synchronization signal,
JP-A-57-164443 and JP-A-56-10165
2 and JP-A-56-137531. In these examples, one type of long pattern is used as the synchronization signal.

Further, Japanese Patent Publication No. 56-4888 discloses a magnetic recording technique using a mark having a pulse pattern which does not appear in data.

[0005]

As described above, the sector mark is effective for access control and signal detection during read / write, but the detection reliability must be sufficiently high for that reason. By the way, it is difficult to sufficiently reduce defects such as recording film defects and noise in an optical disc, and the pit error rate is 1
It is necessary to make a device that allows an error of about 0 ^-8 to 10 ⁸ . Of the above errors, burst errors (errors are concentrated in a certain range of bits) are more problematic than random errors (errors in bit units independently occur).

The reliability of the recorded data is improved by adding an error correction code. Further, with respect to burst error, it is possible to disperse the burst error by an interleaving method of dispersively recording data, and it is possible to cope with a considerably long burst error. However, the above method cannot be applied to the sector mark detection, and therefore cannot be put to practical use without some kind of high reliability means.

In contrast to the above situation, the conventional apparatus has a problem in that there is no means for increasing the reliability of detecting the mark.

It is an object of the present invention to provide a mark recording pattern which can improve the detection reliability of the special mark such as the sector mark and a detecting device therefor.

[0009]

In order to solve the above problems, the present invention records binary data in a circular pit shape corresponding to the "1" or "0" position along a track on an optical disk. In the optical information recording / reproducing method for reproducing, at predetermined intervals along the track on the optical disc,
An identification mark composed of a plurality of oval pits whose length in the track direction is longer than the circular pit of data is formed.
This identification mark is detected and data is recorded between the identification marks.

When the identification mark is detected, the length of the elliptical pit in the track direction is identified to detect the identification mark.

In the optical disk device of the present invention, the mark element pattern having a shape different from the data element pattern forming the coded information to be recorded and the combination thereof is used as a constituent element, a plurality of mark element patterns are used, and the distance between them is used. A pattern array that is connected in series with a specific array including is recorded as an identification mark for each predetermined recording unit, and is read from a disc medium having a recording area for recording coded information between the identification marks. Means for binarizing the generated signal, means for detecting each of the mark element patterns from the binarized signal and parallelizing the detected signals, and comparing the number of the parallelized detected signals with a predetermined threshold value. And a logic means for obtaining a detection signal of the identification mark.

[0012]

The condition required for the identification mark such as the sector mark is that even if there is a defect in the medium, if it is within a certain limit, it can be detected correctly, and a false detection signal is output at a point other than the original place. It is necessary not to. Furthermore, unlike the data reproduction method, it is possible to use a specific timing of the clock signal.
It is necessary to be able to detect without using the method of judging 1 "" 0 ". In addition, it is also necessary to make the pattern of the mark part so as not to give a large disturbance to the automatic focus control and tracking control in the optical disc device. Therefore, in the present invention, as a method for detecting the mark pattern, (1) the element part is an element pattern having a shape that cannot occur in any combination of data in the data part (2) One to several types of shape element patterns are used. (3) A predetermined recording unit with a pattern row in which a plurality of element patterns of the above shape are connected in series in a specific array including the mutual intervals as marks. (4) each of the above element patterns is detected, and (5) some of the plurality of element patterns are erroneously detected or not detected. It is characterized in that detecting by means of the threshold logic such as to allow also the correct detection.

[0013]

The present invention will be described in detail with reference to the following examples.
FIG. 1A is a diagram showing an example of a recording format on an optical disc. Recording is done along spiral or concentric tracks on the disk surface, each track being divided into sectors.

FIG. 1 shows an example of a sector recording format. There is a sector mark 1 at the beginning of a sector, and an address area 40 for identifying recorded information is recorded. After that, there are a VFO area 20 for clocking when reading the address information 40 and the like, and a sync signal section 30 indicating the start point of the address. In most cases sector mark 1, VFO2
The portion of 0, the synchronizing signal 30, and the address 40 is built in the disc in advance (preformat). On the other hand, the latter half data section 41 is an area of data to be recorded. Reference numerals 21 and 31 are the VFO (clocking portion) 21 and the synchronization signal portion 31 for reading the recorded data 41 with the same functions as the VFO 20 and the synchronization signal 30. The sector mark 1 indicates the start of a sector, and is specifically used for control for reading the address portion and for writing and reading the data portion.

That is, as shown in FIG. 1B, the sector mark detection signal 10 is used to control the clock recovery circuits 200 and 210, and the synchronization signal detection gate signals 300 and 31.
0 and write sequence activation signal 410 for writing
And so on, and the read / write operation is executed. Obviously, the sector mark 1 serves as a reference for the subsequent clock generation, and therefore, the sector mark 1 itself needs to be detected without using the clock.

FIG. 2 shows an example of the data coding rule in this embodiment. A data word is converted into a code word in units of 2 to 4 bits, and information is recorded on the disc in a portion corresponding to "1" of the code word. The coding rule as shown in FIG. 2 is called a (2,7) modulation method.

FIG. 3 shows a data recording method. Figure 3
(A) is a code word, and FIG. 3 (B) is recording information on the disc. In FIG. 3, reference numeral 50 denotes information indicating a track.
Is recording information (a deformed state of the recording film). A blank is recorded at a position corresponding to the code word “0”, and recording information 51 is recorded at a position corresponding to “1” in the form of hole formation or phase change.

FIG. 3C shows an embodiment of the element pattern of the sector mark according to the present invention. Since the element pattern of the data is recorded in the form of 51 in FIG. 3B, the element pattern 100 of FIG. 3C cannot be formed by any combination of 51, which makes it easy to identify the data and the mark. ing. In the present invention, a plurality of element patterns 100 as described above are combined to form a sector mark. The sector mark is detected by recognizing the length of the element pattern 100 and the interval between the element patterns 100. Therefore, the recording principle is different from the element pattern 51 of the data indicating the position of the data "1", which facilitates detection of the sector mark and enables detection without using a clock. In the present invention, the sector mark element pattern 1
00 is the element pattern 51 of the data as shown in FIG.
Longer in the track direction. With such a pattern configuration, the signal from the sector mark has a higher intensity than the signal from the data. Therefore, the detection of the sector mark becomes more stable. Unlike data, sector marks cannot be corrected even if there are errors. This is because the sector mark is located at the beginning of the data and it is necessary to recognize the sector mark at the same time as the detection because it is used as a reference for the subsequent clock and data, and there is no room for re-reading and error correction. .. Therefore, the larger the signal output, the better.

FIG. 4 shows an embodiment of the sector mark pattern. Specifically, the sector mark 1 portion in FIG. 4A uses five element patterns such as 100 in FIG. 3C. Here, two types of element patterns are used, and the lengths of 101 and 105 are 6 code bits in code word units,
The other three, 102, 103 and 104, have a 4 code bit length. As the sector mark pattern, the intervals between the above element patterns also have an important meaning. In FIG. 4B, 10
The distance between 1 and 102 is 6, the distance between 102 and 103 is 10,
The intervals 103 and 104 and 104 and 105 are 4 code bits.

FIG. 5 is a block diagram of a detection circuit for the mark shown in FIG. Reference numeral 60 denotes a signal detected by the optical head, which passes through an amplifier 61 and is converted into a width signal by a binarizing circuit 62. The circuit 63 detects that the signal read by the width detection circuit has a width satisfying the sector mark condition. Reference numeral 64 is a circuit for parallelizing the width detection output by 63 based on the pattern detection and the time relationship, and outputs five outputs simultaneously (in parallel) corresponding to the five patterns in FIG. 4B. Reference numeral 65 denotes a threshold value logic circuit, which determines a sector mark when three or more of the above five detection signals are present and outputs the detection signal 10.

FIG. 6A shows a concrete configuration of the binarizing circuit 62 shown in FIG. The output waveform 610 of the amplifier 61 is shown in FIG.
It is shown in (b). The differential or differentiating circuit 621 forms the waveform as shown in FIG. 6C, and the peak detection circuit 622 forms the width signal 620 as shown in FIG. 6D corresponding to the negative and positive peak points.

FIG. 7 shows a specific structure of the width detection circuit 63. Reference numeral 631 is a sufficiently fast clock generator, which counts this with a counter 632, but controls the width with a width signal 620 to detect the width. At the end of the width signal, the decoder 633 determines the contents of the counter 632 and outputs the width detection signal 630.
Since the width detection signal is generated in time series corresponding to the pattern of FIG. 4, it is parallelized by the serial-parallel circuit 64.

FIG. 8 shows a specific example of the serial-parallel circuit. Of the width detection outputs, the detection outputs of patterns 101 and 105 (width 5 code pits r = 5) of FIG.
Detection outputs of 103 and 104 (width 4 code pits r = 4) are 6302, and two shift registers 641 and 64 are provided.
2 and in parallel on output 640. This parallel signal is judged by the threshold logic circuit 65 to obtain the sector mark detection signal 10. The threshold logic circuit produces an output when m or more (m <n) of n inputs are satisfied, and (n, m) + (n, m + 1) + ... + (n,
It is possible to combine the logic circuit with the combination of n). If n = 5 and m = 3, (5,3) + (5,4) +
(5,5) = 16 ways. There is no particular problem with this method of implementation, so description thereof will be omitted.

FIG. 9 is a diagram for explaining the operation of detecting the sector mark signal 10 from the serial / parallel circuit 64 and the threshold logic circuit 65.

The mark (a) is a mark recorded on the same track 50 as that shown in FIG. When the mark portion is read while the disk is rotated and is tracked by the optical head, a detection output of r = 6 and r = 4 is generated from the width detection circuit with respect to time t, and each signal line 640 is passed through the shift register circuit. 0
1, 02, 03, 04, 05 occur with the pulse time t shown in FIG. For example, pattern 101
The r = 6 signal detected from is sent to the shift register 641 via 6301, and as a result, the output line 01 is pulsed to 0.
11 produces a pulse 012 on output 05. Regarding the pattern 102, the r = 4 detection signal is taken into the shift register 642 via 6302, and the pulse 0 is output to the output line 02.
21, pulse 022 on output line 03 and pulse 023 on output line 04.

The same operation is performed for other signals, and as a result, all the output lines 01 to 05 simultaneously become "1" at t = 0. When t ≠ 0, at most one signal line becomes “1”. This state is shown in FIG. Therefore, if the output pulse 10 is obtained by the threshold value logic circuit 55 when the number that becomes "1" at the same time is 3 or more, the mark detection pulse can be obtained only at t = 0. As is clear from the above description, the output pulse 10 can be obtained without any two of the five signals 01 to 05. That is, normal mark detection can be performed even if two arbitrary patterns cannot be detected due to lack of a medium or the like.

The important point here is that no false signal is generated at a point other than t ≠ 0 even if an error occurs due to the above-mentioned lack. The pattern arrangement of the embodiment of FIG. 4 is defined from this point. The reason why the false signal is not output when t ≠ 0 is that there is a property that at most one signal line becomes "1" except t ≠ 0 in FIG. 9C. This property is derived from the fact that the mark arrangement pattern in FIG. 4 has the property of "self orthogonal". Therefore, as long as it has the property of being self-orthogonal, the same effect can be obtained not only in the arrangement of the embodiment of FIG. 4 but also in other pattern arrangements. The reason why two types of patterns of r = 6 and r = 4 are used in FIG. 4 is to have the above-described self-orthogonal property and to shorten the mark pattern area. That is, the two types of patterns may be orthogonal to each other.

Specifically, as shown in FIG. 9, a pulse indicating the position of the element pattern is formed. Next, for example, when pulses of long element patterns of 101 and 105 are overlapped as parallel outputs with their phases being shifted, the pulses do not overlap except for the overlapped pulses. Similarly, the three pulses indicating the short element patterns of 102, 103, and 104 do not overlap each other except at the time t = 0. As described above, the pattern in which the three second patterns are arranged at unequal intervals between the two first patterns is typical.

However, there is a possibility that one pattern cannot be distinguished from another type pattern due to an error. The mark pattern arrangement is determined in consideration of these points. The mark length in the embodiment of FIG. 4 is 48 code bits. In this pattern, even if an error occurs up to two arbitrary patterns or a single burst error with a length of 1 byte (= 16 code bits) or less occurs, the correct mark is generated. It can be detected. The mark pattern length may be increased to further improve the error resistance capability.

[0030]

As described above, according to the present invention, a special mark different from data such as a sector mark can be detected with high reliability without being affected by a defect of a medium or noise. In other words, a pattern that does not occur due to any combination of data in a format different from the data modulation method is used as a mark configuration pattern, and a plurality of these patterns are used to determine the mark detection by the threshold logic. Thus, the probability of loss of the detection signal at the normal time is remarkably reduced and the probability of generation of a false signal at a point other than the normal point is remarkably reduced, so that read / write control in the optical disk device can be facilitated and highly reliable.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a recording format on an optical disc.

FIG. 2 is a code diagram showing an example of a recording data encoding method.

FIG. 3 is a plan view of a mark pattern according to the present invention.

FIG. 4 is a conceptual diagram of a sector mark pattern showing an embodiment of the present invention.

FIG. 5 is a block diagram showing an embodiment of the configuration of a mark detection circuit.

6 is a conceptual diagram showing a configuration of a pattern binarization circuit in FIG.

7 is a block diagram showing a configuration of a width detection circuit in FIG.

8 is a block diagram showing a configuration of a serial-parallel conversion circuit and a mark output circuit in FIG.

FIG. 9 is an operation explanatory diagram of FIG. 8;

[Explanation of symbols]

1 ... Sector mark, 20 ... Clock signal part, 50 ... Track, 101 ... Pattern, 102 ... Pattern, 103 ... Pattern, 104 ... Pattern, 105 ... Pattern

Claims (31)

[Claims] 1. A mark element pattern having a shape different from that of a data element pattern and a combination thereof constituting coded information to be recorded is used as a constituent element, and a plurality of mark element patterns are used and specified including their mutual intervals. A signal read from a disc medium having a recording area for recording the above-mentioned coded information between the identification marks, which is recorded in each predetermined recording unit as an identification mark of a pattern string connected in series in the arrangement of For binarizing, the means for detecting each of the mark element patterns from the binarized signal and parallelizing the detected signals, and the number of the parallelized detected signals as a predetermined threshold value. A recording / reproducing apparatus having a logic means for comparing and obtaining a detection signal of the identification mark. 2. The recording / reproducing apparatus according to claim 1, wherein the identification mark is a pattern sequence in which the plurality of mark element patterns are arranged so that the detection signals are orthogonal to each other. 3. The recording / reproducing apparatus according to claim 1, wherein each of the mark element patterns is longer than a data element pattern forming the coded information. 4. The recording / reproducing apparatus according to claim 1, wherein two types of mark element patterns having different lengths are used. 5. The recording / reproducing apparatus according to claim 4, wherein the number of the mark element patterns is five. 6. A mark element pattern 3 between two mark element patterns of the first kind.
6. The recording / reproducing apparatus according to claim 5, wherein the recording / reproducing apparatus has a pattern row in which the second type mark element patterns are arranged. 7. When the mark element patterns are sequentially numbered from the beginning, the distance between the second and third mark element patterns is the longest, and the distance between the third and fourth mark element patterns is the shortest. 7. The recording / reproducing apparatus according to claim 5, wherein the pattern row of the identification marks is configured as described above. 8. When the mark element patterns are sequentially numbered from the beginning, the intervals between the third and fourth mark element patterns and the intervals between the fourth and fifth mark element patterns are equal to each other. 8. The recording / reproducing apparatus according to claim 5, wherein a pattern row of identification marks is formed. 9. When the mark element patterns are sequentially numbered from the beginning, the first and fifth mark element patterns are the longest, and there are three shorter mark element patterns between them. 9. The recording / reproducing apparatus according to claim 5, wherein a pattern array of identification marks is formed. 10. When the mark element patterns are sequentially numbered from the beginning, the identification mark is such that the ratio of the lengths of the mark patterns is 6, 4, 4, 4, 6 in order from the first mark pattern. 10. The recording / reproducing apparatus according to any one of claims 5 to 9, wherein the recording / reproducing apparatus comprises a pattern array of. 11. When the mark element patterns are sequentially numbered from the beginning, the ratio of the lengths of intervals of the mark patterns is
The recording / reproducing apparatus according to any one of claims 5 to 10, wherein the pattern row of the identification marks is configured so as to be 6, 10, 4, 4 in order from the first side. 12. Address information, clocking for reading the address information, and synchronization information indicating a starting point of the address information are preliminarily built in the disk medium by being connected in series to the identification mark, and the logical 12. The recording / reproducing apparatus according to claim 1, wherein a detection signal of an identification mark obtained from the means is used for reading control of the clocking and synchronizing signals. 13. The parallelizing means detects the width of the binarized signal, obtains the detection signal at each end of the element pattern, and outputs the detection signals for a predetermined time respectively. 13. The recording / reproducing apparatus according to claim 1, comprising a means for delaying. 14. The recording / reproducing apparatus according to claim 1, wherein when the number of element patterns constituting the identification mark is 5, the threshold value is 3. 15. A disc-shaped recording medium, and an identification mark composed of five mark element patterns arranged on the recording medium at predetermined intervals along a track, and information is recorded between the identification marks. In the information recording apparatus, when the mark element patterns are sequentially numbered from the beginning, the distance between the second and third mark element patterns is the longest, and the distance between the third and fourth mark element patterns is the shortest. An information recording apparatus, characterized in that a pattern row of the identification marks is formed so as to make it difficult. 16. A disc-shaped recording medium, and an identification mark composed of five mark element patterns arranged on the recording medium at predetermined intervals along a track, and information is recorded between the identification marks. In the information recording apparatus, when the mark element patterns are sequentially numbered from the beginning, the first and fifth mark element patterns are the longest, and three mark element patterns shorter than that are present between them. An information recording apparatus comprising a pattern array of the identification marks. 17. A disc-shaped recording medium, and an identification mark composed of five mark element patterns arranged on the recording medium at predetermined intervals along a track, and information is recorded between the identification marks. In the information recording apparatus, when the mark element patterns are sequentially numbered from the beginning, the distance between the second and third mark element patterns is the longest, and the distance between the third and fourth mark element patterns is the shortest. Information that is characterized in that the pattern row of the identification mark is configured such that the first and fifth mark element patterns are the longest and three mark element patterns shorter than that are present between them. Recording device. 18. When the mark element patterns are sequentially numbered from the beginning, the intervals between the third and fourth mark element patterns and the intervals between the fourth and fifth mark element patterns are equal to each other. 18. The information recording apparatus according to claim 15, wherein a pattern row of identification marks is formed. 19. A code conversion method for encoding the above information and recording it on the recording medium as a pattern sequence of data element patterns, wherein the means does not include the mark element pattern in the pattern sequence of the data element patterns. The information recording apparatus according to any one of claims 15 to 18, characterized in that: 20. A mark element pattern having a shape different from that of a data element pattern constituting the coded information to be recorded and a combination thereof is used as a constituent element, and a plurality of the mark element patterns are used and specified including their mutual intervals. A signal read from a disc medium having a recording area for recording the above-mentioned coded information between the identification marks, which is recorded in each predetermined recording unit as an identification mark of a pattern string connected in series in the arrangement of Is binarized, each of the mark element patterns is detected from the binarized signal, the detection signals are parallelized, and the number of the parallelized detection signals is compared with a predetermined threshold value to identify the identification mark. A detection method of a mark, characterized by obtaining a detection signal of. 21. The mark detecting method according to claim 20, wherein a pattern row in which the plurality of mark element patterns are arranged so that the detection signals are orthogonal to each other is used as the identification mark. 22. The mark detecting method according to claim 20, wherein each of the mark element patterns is longer than a data element pattern forming the coded information. 23. The mark element pattern according to claim 20, wherein two types having different lengths are used.
2. The mark detection method according to any one of 2 above. 24. The mark detecting method according to claim 23, wherein the number of mark element patterns is five. 25. The mark detecting method according to claim 24, wherein a pattern row in which three mark element patterns of the second type are arranged between two mark element patterns of the first type is used. 26. An optical information recording / reproducing method for recording and reproducing binarized data in a circular pit shape corresponding to the "1" or "0" position along a track on the optical disk, At predetermined intervals along the track, identification marks made of plural kinds of elliptical pits having a length in the track direction longer than the circular pits are formed,
An optical information recording / reproducing method of detecting the identification mark and recording the data between the identification marks. 27. The optical information recording / reproducing method according to claim 26, wherein the identification mark is detected by identifying the length of the elliptical pit in the track direction. 28. An optical information recording / reproducing method for recording and reproducing binarized data in a circular pit shape corresponding to a "1" or "0" position along a track on the optical disk, An identification mark composed of plural kinds of elliptical pits having a length in the track direction longer than the circular pits and a clock generation signal thereafter are formed at predetermined intervals along the track, and the identification signal is sent from the identification mark. An optical information recording / reproducing method of detecting, generating a clock according to the identification signal and the clock generating signal, and recording or reproducing the data based on the clock. 29. An optical information recording / reproducing method for recording and reproducing binarized data in a circular pit shape corresponding to the "1" or "0" position along a track on the optical disk, An identification mark composed of plural kinds of elliptical pits having a length in the track direction longer than the circular pits and a synchronizing signal after that are formed at predetermined intervals along the track, and the identification signal is detected from the identification mark. An optical information recording / reproducing method for detecting the synchronization signal based on the identification signal. 30. The binarized data is recorded along the track.
In an optical information recording medium for recording and reproducing in a circular pit shape corresponding to a 1 "or" 0 "position, it is composed of a plurality of kinds of elliptical pits having a length along a track which is longer in the track direction than the circular pit. An optical system in which an identification mark is formed, a clock generation signal is formed after the identification mark, a synchronization signal is formed after the clock generation signal, and the binarized data recording area is formed after the synchronization signal. Information recording medium. 31. Binarized data is recorded along a track.
In an optical information recording medium for recording and reproducing in a circular pit shape corresponding to a 1 "or" 0 "position, it is composed of a plurality of kinds of elliptical pits having a length along a track which is longer in the track direction than the circular pit. An identification mark is formed, a first clock generation signal is formed after the first identification mark, a first synchronization signal is formed after the first clock generation signal, and the first synchronization signal is formed. Is formed after the address signal, the second clock generation signal is formed after the address signal, the second synchronization signal is formed after the second clock generation signal, and the second synchronization signal is formed after the second synchronization signal. An optical information recording medium in which a recording area for the binary data is formed.