JPH0855430A - Information recorder and optical information recording medium - Google Patents

Abstract

PURPOSE:To obtain recording patterns of marks capable of improving detection reliability of special marks, such as center marks, and a detector thereof. CONSTITUTION:Binarized data is recorded and reproduced by circular pits 51 corresponding to its '1' or '0' position along a track 50 on an optical disk. The identification marks consisting of plural pieces of elliptic pits 100 which are longer in the track direction than the circular pits of the data are formed at prescribed intervals along the track 50 on the optical disk and the data is recorded between the dientification marks by detecting these 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 disk, it is useful to mark the starting point of each recording unit in random access, read / write control and the like. Here, the 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. These show examples in which 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
0 ^-8 10 ⁸ about Ella need to make a device such as will allow. Of the above errors, burst error (errors are concentrated in a certain range of bits) is more problematic than random error (errors in bit units occur independently).

The reliability of 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 interleave method of recording data in a dispersed manner, 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 improving 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 along a track on an optical disk in a circular pit shape corresponding to its "1" or "0" position. In the optical information recording / reproducing method of reproducing, at predetermined intervals along the track on the optical disc,
An identification mark composed of a plurality of elliptical pits whose length in the track direction is longer than the circular pit of data is formed,
When the identification mark is characterized by detecting the identification mark and recording data between the identification marks, 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 sequence in which a pattern is connected in series with a specific array 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. Comparing the number of parallelized detection signals with a predetermined threshold value, a means for binarizing the detected signal, a means for detecting each mark element pattern from the binarized signal and parallelizing the detection signals. And a logic means for obtaining a detection signal of the identification mark.

[0011]

The condition required for an identification mark such as a sector mark is that even if the medium has a defect, it can be correctly detected within a certain limit, and a false detection signal is output at a point other than the original position. 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 such that it does not cause a large disturbance to the automatic focus control and tracking control in the optical disc device. Therefore, in the present invention, as a method of detecting the mark pattern, (1) an element pattern having a shape that cannot occur in any combination of data in the data part is used as a constituent element (2) 1 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 shapes are connected in series in a specific arrangement including the intervals between them as a mark. Record each (4)
While detecting each of the above element patterns, (5) some of the plurality of element patterns are erroneously detected,
Even if it is not detected, it is detected by means such as threshold value logic so that correct detection can be performed.

[0012]

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 performed 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 0, sync signal 30, and address 40 parts are built in the disk 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 a 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. FIG.
(A) is a code word, and FIG. 3 (B) is recording information on the disc. In FIG. 3, reference numeral 50 is information indicating a track.
Is the recording information (the deformed state of the recording film). A blank is recorded at a position corresponding to the code word “0”, and record 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 of FIG. 3B, the element pattern 100 of FIG. 3C cannot be formed by any combination of 51, which facilitates the identification of 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 the detection of the sector mark and enables the detection without using the clock. Further, in the present invention, the sector mark element pattern 1
00 is an element pattern 51 of data as shown in FIG.
Longer in the track direction. With this 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, for the portion of the sector mark 1 in FIG. 4A, five element patterns such as 100 in FIG. 3C are used. 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 between 103 and 104 and 104 and 105 are 4 code bits.

FIG. 5 is a block diagram of a detection circuit for the mark 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 condition of the sector mark. 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 structure 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 value logic circuit 65 to obtain the sector mark detection signal 10. The threshold logic circuit generates 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 is omitted.

FIG. 9 is an explanatory diagram of the operation of detecting the sector mark signal 10 from the serial / parallel circuit 64 and the threshold value logic circuit 65. (A) is a mark recorded on the same track 50 as in (B) of FIG. . When the mark portion is read while the disk is rotated and is tracked by the optical head, the detection signals of r = 6 and r = 4 are generated from the width detection circuit with respect to time t.
640 signal lines 01, 0 through the shift register circuit
2, 03, 04 and 05 occur with the pulse time t shown in FIG. For example, the r = 6 signal detected from the pattern 101 passes through 6301 and then shift register 6
41, and as a result, output line 01 pulse 011
Generate a pulse 012 on output 05. Pattern 10
For 2, the r = 4 detection signal is taken into the shift register 642 via 6302, and the pulse 021 is output to the output line 02.
, A pulse 022 is generated on the output line 03, and a pulse 023 is generated on the output line 04.

Similar operations are 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 apparent 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 the medium or the like.

An 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 a false signal is not output when t ≠ 0 is shown in Fig. 9 (c).
This is because, except t ≠ 0, only one line number has a property of "1" at most. 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 that the mark pattern area is shortened while having the self-orthogonal property. 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 101 and 105 are overlapped as parallel outputs with their phases shifted, pulses do not overlap except for the overlapped pulses. Similarly, the three pulses showing the short element patterns of 102, 103, and 104 do not cause pulse overlap, except that the pulses overlap at the time of t = 0. In this way, a typical pattern is one in which three second patterns are arranged at unequal intervals between two first patterns.

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.

[0028]

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 influenced 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 significantly reduced and the probability of generation of a false signal at a point other than the normal point is also significantly 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.

FIG. 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 (6)

[Claims] 1. An identification mark comprising five mark element patterns arranged at predetermined intervals along a track,
When the mark element patterns are numbered from the beginning,
The distance between the second and third mark element patterns is the longest,
An information recording apparatus for recording information between the identification marks of a recording medium on which a pattern sequence of the identification marks is formed so that the interval between the third and fourth mark element patterns is the shortest. And has means for recording on the recording medium as a pattern sequence of data element patterns by encoding
The information recording apparatus is characterized in that the means performs code conversion in which the mark element pattern does not exist in the pattern sequence of the data element pattern. 2. An identification mark comprising five mark element patterns arranged at predetermined intervals along a track,
When the mark element patterns are numbered from the beginning,
Information is provided between the identification marks of the recording medium in which the identification mark pattern sequence is configured such that the first and fifth mark element patterns have the longest length and three shorter mark element patterns are present therebetween. An information recording device for recording, comprising means for encoding the information and recording it on the recording medium as a pattern sequence of data element patterns, wherein the means includes the mark element patterns in the pattern sequence of the data element patterns. An information recording device characterized by performing code conversion that does not exist. 3. An identification mark composed of five mark element patterns arranged at predetermined intervals along a track, and when the mark element patterns are sequentially numbered from the beginning, the second and third marks are provided. Three mark elements with the longest element pattern intervals, the shortest intervals between the third and fourth mark element patterns, and the longest first and fifth mark element patterns, and between them. An information recording device for recording information between the identification marks of a recording medium in which a pattern sequence of the identification marks is formed so that patterns exist, and is used as a pattern sequence of data element patterns by encoding the information. It has a means for recording on the recording medium, and the means performs code conversion in which the mark element pattern does not exist in the pattern sequence of the data element pattern. Broadcast recording device. 4. When the mark element patterns are sequentially numbered from the beginning, the distance between the third and fourth mark element patterns and the distance between the fourth and fifth mark element patterns are equal to each other. 4. The information recording apparatus according to claim 1, wherein a pattern row of identification marks is formed. 5. The means for encoding the above information and recording it on the above recording medium as a pattern sequence of data element patterns has a circular pit shape corresponding to the "1" or "0" position of the binarized data. The information recording apparatus according to claim 1, wherein the information is recorded on a recording medium. 6. Binarized data 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, the optical information recording medium is composed of plural kinds of elliptical pits having a length in the track direction longer than the circular pit along the track. 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.