JPH06215486A - Information recording medium - Google Patents

Abstract

PURPOSE:To remove a limitation on a format by providing a wobble mark group generating tracking error signals with reverse polarities each other alternately and so that the total number of the wobble mark groups per one track become an odd number. CONSTITUTION:The first wobble mark groups 11a, 11b, 12a, 12b and the second wobble mark groups 13a, 13b, 14a, 14b are formed alternately. At this time, the number of wobble mark pairs constituting the wobble mark groups is defined M, and the number of the wobble mark groups per one track period is defined N. In such a case, though the N must be the odd number, the M need not be the odd number. Thus, when the M is defined an even number, the even number pieces of the wobble mark pairs per one track are arranged finally since the number of pieces of the wobble mark pairs per one track is MXN, and the limitation on the format as usual is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc-shaped information recording medium capable of optical or magnetic high density recording.

[0002]

2. Description of the Related Art In recent years, optical or magnetic information recording media have been steadily on the road to higher density.

An example of the above-mentioned conventional information recording medium will be described below with reference to the drawings.

FIG. 4 is a block diagram showing the essential parts of an information recording medium in a conventional example. In FIG. 4, 100 is a part of the track center line provided in a spiral shape. 1
Reference numerals 11a and 111b are first wobble mark pairs formed along the track center line 100, and 112a and 112b are second wobble mark pairs formed along the same track center line 10. The distance of the wobble mark from the track center line is 1/2 track pitch. The first wobble mark pair 111a, 111b and the second
The difference from the wobble mark pairs 112a and 112b is that the wobble marks are arranged in the opposite positions, as clearly shown in FIG. That is, the tracking error signals obtained from the second wobble mark pairs 112a and 112b have opposite polarities to the tracking error signals obtained from the first wobble mark pair 111a and 111b. Further, the first wobble mark pair 111a and 111b and the second wobble mark pair 11 are
2a and 112b are alternately formed, and the total number of the first and second wobble mark pairs is an odd number per track period (track for one round). Note that reference numeral 20 denotes recording information, which is provided between the wobble mark pair and the wobble mark pair.

The operation of the conventional information recording medium configured as described above will be briefly described. First, when a recording / reproducing head such as an optical head or a magnetic head scans the wobble marks 111a and 111b, a (positive polarity) tracking error signal is obtained from the pair of wobble marks. Next, the head is the wobble mark pair 112a,
When scanning over 112b, these polarities are reversed because they provide tracking error signals of opposite polarity (negative polarity). By doing so, tracking error signals having the same polarity can be obtained. Therefore, if the position of the recording / reproducing head is controlled so that the tracking error signal is always 0, the recording / reproducing head can always record or reproduce information along the spiral track.

Thus, if the head scans one track period, the head comes on the adjacent track, but as described above, the total number of positive and negative wobble mark pairs per track period is an odd number. , The position of the positive wobble mark pair on the adjacent track is the preceding track 1
It comes to the position next to the pair of negative wobble marks at 00. The wobble mark 112a forming the negative wobble mark pair in the preceding track forms one corner of the positive wobble mark pair in the adjacent track. The same thing can be said for adjacent tracks.
Eventually, all tracks will be continuously formed in a spiral shape. At this time, the positive wobble marks and the negative wobble marks are arranged in a zigzag pattern.

In the above-mentioned manner, it is possible to realize an information recording medium in which all tracks are continuously connected in a spiral shape even with a narrow track pitch (for example, Japanese Patent Laid-Open No. Hei 4).
No. 319532).

[0008]

However, in the above-mentioned structure, the number of wobble mark pairs is limited to an odd number, which causes a problem that the physical format of the information recording medium is restricted.

[0009]

In order to solve the above-mentioned problems, the information recording medium of the present invention is such that, when M is an even number and N is an odd number, the opposite polarities respectively constituted by M wobble mark pairs. Alternating first wobble mark groups and second wobble mark groups that generate the tracking error signal of
It is arranged so that it becomes an individual.

[0010]

According to the present invention, since the wobble mark groups having the positive and negative tracking error polarities are arranged in a zigzag pattern by the above-described structure, even if the total number per track period is even, Can be spiral-formatted at track pitch.

[0011]

FIG. 2 is a top view of an information recording medium in this embodiment, and FIG. 1 is a configuration diagram of the main part thereof. In FIG. 1, 10 is a part of a track center line provided in a spiral shape. 11a, 11b and 12a, 12b
Are wobble mark pairs formed along the track center line 10, respectively, and these constitute a first wobble mark group. Reference numerals 13a, 13b and 14a, 14b are wobble mark pairs formed along the same track center line 10, and these compose a second wobble mark group. The distance of the wobble mark from the track center line is 1/2 track pitch. The difference between the first wobble mark groups 11a, 11b, 12a, 12b and the second wobble mark groups 13a, 13b, 14a, 14b is that, as clearly shown in FIG. That is. That is, the tracking error signal obtained from the second wobble mark group has the opposite polarity to the tracking error signal obtained from the first wobble mark group. Further, the first wobble mark groups 11a, 11b, 12a, 1
2b and the second wobble mark groups 13a, 13b, 14
It is characterized in that a and 14b are alternately formed, and the total number of the first and second wobble mark groups is an odd number per track period (track for one round). Note that reference numeral 200 is recorded information.

The operation of the conventional information recording medium having the above structure will be described below with reference to FIGS. 1 and 2. First, the heads are wobble mark groups 11a, 11b,
It is assumed that a positive tracking error signal is obtained from these wobble mark groups when scanning 12a and 12b. Next, the head moves to the wobble mark group 13a, 13b, 1
4a, 14b are scanned, but since they provide tracking error signals of opposite polarity (negative polarity), this polarity is reversed. By doing so, tracking error signals having the same polarity can be obtained.

Further, if the head scans one track period, the head comes on the adjacent track, but as described above, one of the positive and negative wobble mark groups is used.
Since the total number per track cycle is an odd number, the position of the positive wobble mark group on the adjacent track comes to the position next to the negative wobble mark group on the preceding track 10. The wobble marks 13b and 14b, which constitute the negative wobble mark group in the preceding track, form one corner of the positive wobble mark pair in the adjacent track. The same applies to the adjacent tracks, and eventually all the tracks are continuously formed in a spiral shape. At this time, the positive wobble marks and the negative wobble marks are arranged in a zigzag pattern.

Here, the number of wobble mark pairs forming the wobble mark group is M, and the number of wobble mark groups per one track period is N. As mentioned above, N
Must be odd, but M need not be odd. Therefore, if M is an even number, the number of wobble mark pairs per one track period is M × N, so that it becomes possible to arrange an even number of wobble mark pairs per one track, which is the case in the conventional example. There is no such format restriction.

Next, a second embodiment of the present invention will be described. FIG. 3 is a top view of the second embodiment of the present invention. Figure 3
, 11a, 11b and 12a, 12b are wobble mark pairs forming the first wobble mark group, and 13a, 13b and 14a, 14b are second wobble mark pairs.
Wobble marks forming a wobble mark group, and these wobble marks are formed along the track 10 and have the same function as that shown in the first embodiment. The difference from the first embodiment is that the truck 10
Along the track 15 formed on the inside of the wobble mark pair 16a, 16b and the wobble mark pair 17a,
17b are provided so that the polarities thereof are alternately inverted. Furthermore, the number of wobble mark pairs per track period is half that of the track 10.

The second embodiment of the present invention constructed as above will be described in detail below. The information recording medium in this embodiment is premised on being formatted so that the linear recording densities of the inner and outer circumferences are substantially constant. That is, in the information recording medium shown in FIG. 3, assuming that the length of one circumference of the outer track 10 is approximately twice the length of one inner track 15, the outer track 10 has almost the same length as the inner track 15. Double the amount of information can be recorded. At this time, the number of wobble mark pairs per track is twice as large as the inner circumference at the outer circumference, but in the present embodiment, the number M of wobble mark pairs in one wobble mark group out of the total number M × N.
This is dealt with by doubling. That is, in the example of FIG. 3, (M =) 1 × (N =) on 15 tracks on the inner circumference side.
3 = 3 wobble mark pairs are provided, and the outer track 1
0 (M =) 2 × (N =) 3 = 6 wobble mark pairs are provided. As a result, as shown in FIG. 3, the inner circumference side wobble mark pair 16a, 16b, the outer circumference side wobble mark pair 12a, 12b, and the inner circumference side wobble mark pair 17
a, 17b and the outer side wobble mark pair 14a, 14b,
Will be provided on the same radial line (dotted line in the figure).

By arranging the wobble mark pairs on the inner and outer tracks as described above, it is possible to realize an information recording medium which is synchronized over the entire recording area. In other words, the recording / reproducing head frequently travels between the inner and outer tracks and must track the tracks 10 and 15 each time. At this time, if the wobble mark pair 1
If the wobble mark pairs 2a and 12b and the wobble mark pair 16a and 16b are not on the same radial line, the wobble mark pair is lost when the recording / reproducing head accesses the track 10 to the track 15 or the track 15 to the track 10 as a result. The rapid tracking operation will not be performed. According to the present embodiment, the access and tracking operations can be executed quickly by using the inner-outer circumference synchronization format.

Further, in this embodiment, the number M of wobble mark pairs per wobble mark group is increased or decreased to set the number of wobble mark pairs per inner / outer track. It is also possible to synchronize the wobble mark polarity inversion rule in the track. Now referring to FIG. 3, the inner and outer track 10,
The polarity of the wobble mark in 15 is track 10 positive positive negative negative negative positive positive track 15 positive − negative − positive −. That is, both tracks have the same wobble mark polarity inversion count and inversion timing. Therefore, according to this embodiment, it is not necessary to change the tracking polarity inversion rule on the inner and outer circumferences, and a simple format can be achieved.

[0019]

As described above, according to the present invention, wobble mark groups for generating tracking error signals having polarities opposite to each other are alternately provided, and the total number of wobble mark groups per track period is an odd number. It is possible to realize an information recording medium in which the track density is double that of the conventional one, and the number of polarity inversions for obtaining the tracking signal can be reduced, and all the tracks are continuously connected in a spiral shape.

[Brief description of drawings]

FIG. 1 is a configuration diagram of essential parts of an information recording medium in a first embodiment of the present invention.

FIG. 2 is a top view of the information recording medium in the first embodiment of the present invention.

FIG. 3 is a top view of the information recording medium in the second embodiment of the present invention.

FIG. 4 is a configuration diagram of main parts of a conventional information recording medium.

[Explanation of symbols]

 10 Track center lines 11a, 11b Wobble marks of the first group 12a, 12b Wobble marks of the first group 13a, 13b Wobble marks of the second group 14a, 14b Wobble marks of the second group 20 Recording information

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shinichi Kadowaki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (6)

[Claims] 1. An information recording medium in which M × N tracking marks per track unit are periodically and discretely arranged along a spirally provided track center line, wherein Is an odd number,
The information recording medium is characterized in that the tracking marks are provided by reversing the polarity thereof every M integers of 2 or more. 2. The M is an even number.
Information recording medium described. 3. The information recording medium according to claim 1, wherein each of the tracking marks comprises a pair of wobble marks. 4. An information recording medium in which tracking marks are periodically and discretely arranged along a track center line provided in a spiral shape, each of which is composed of at least two zones each composed of a plurality of tracks. The number of tracking marks provided per track unit in the inner peripheral zone is Mi × N, and the number of tracking marks provided per track unit in the outer peripheral zone is Mo × N.
When N is set, the tracking mark in the inner peripheral zone is provided by inverting the polarity for each Mi, and the tracking mark in the outer peripheral zone is provided by inverting the polarity for each Mo. And an information recording medium characterized in that Mo ≧ 2 × Mi. 5. The information recording medium according to claim 4, wherein Mi = 1 and Mo = 2. 6. The information recording medium according to claim 4, wherein each of the tracking marks comprises a pair of wobble marks.